CN117363093A

CN117363093A - White ink composition for LED and preparation method and application thereof

Info

Publication number: CN117363093A
Application number: CN202311495001.3A
Authority: CN
Inventors: 邵文龙; 曹航超; 陈小朋; 吉祥; 温鼎伦
Original assignee: Corevoxel Hangzhou Technology Development Co ltd
Current assignee: Corevoxel Hangzhou Technology Development Co ltd
Priority date: 2023-11-10
Filing date: 2023-11-10
Publication date: 2024-01-09

Abstract

The invention belongs to the technical field of ink, and particularly relates to a white ink composition for an LED, and a preparation method and application thereof. When the reflectivity of the white ink is improved by more than 4%, the thickness of the whole adhesive layer can be reduced to half of the original thickness, and the raw materials which can be saved can be further realized to be more than 40% of the original thickness. On the premise of not reducing the thickness of the integral adhesive layer, the light efficiency utilization rate can be improved by more than 3%, and the integral display effect is obviously improved; and when the same light efficiency utilization rate is achieved, the service life of the whole device can be prolonged by more than 10 percent. By adopting titanium dioxide with different particle sizes and specific proportions, and adding modified fumed silica and/or other anti-settling agents, and adding dispersing agents, leveling agents and diluents, the white ink product with the thickness of the adhesive layer of more than 94 percent, excellent anti-settling performance, scratch resistance, ageing resistance, durability and high reliability is formed, the viscosity uniformity of the white ink in the standing storage process is effectively improved, and the storage applicable period of the white ink is prolonged.

Description

White ink composition for LED and preparation method and application thereof

Technical Field

The invention belongs to the technical field of ink, and particularly relates to a white ink composition for an LED, and a preparation method and application thereof.

Background

Since the advent of liquid crystal displays, LCD display technology has been applied for more than 20 years. The basic principle of LCD display is that the liquid crystal is turned on when the liquid crystal is electrified, the liquid crystal molecules are arranged orderly, so that the backlight light on the side or the lower side is easy to pass through; when the power is not applied, the liquid crystal molecules are arranged in disorder, light is blocked from passing through, and after the LCD backlight passes through the liquid crystal molecules and the color filters, the color patterning conversion is realized. As the 'behind the scenes' of LCD display, the backlight source is updated in the continuous development of technology and market, from the original CCFL backlight to SMD LED backlight and quantum dot backlight, to the current Mini LED backlight, the continuous development of backlight technology is realized, so that the display effect of LCD is continuously improved, and people can enjoy the feast of ultra-high definition vision.

Compared with the traditional LED backlight source, the Mini LED backlight source has more advantages and is more suitable for a high-end liquid crystal display application scheme: firstly, the Mini LED backlight adopts an LED module of three primary colors of RGB, combines with fine Local Dimming to realize vivid display effect of three primary colors of RGB, realizes million-level contrast, can cover 100% of wide color gamut of BT2020, and has color vividness comparable to OLED; secondly, the Mini LED backlight can realize uniform heat dissipation under high brightness (more than 1000 nit), which cannot be realized by the traditional discrete LED device scheme; finally, compared with a general side-in backlight scheme, the Mini LED backlight can achieve direct type ultrathin LCD display, namely OD is approximately equal to 0mm, and has very broad application prospects in light and thin portable consumer electronics markets, such as AR/VR glasses, mobile phones, televisions and the like.

The light valve action of the liquid crystal in the LCD must be premised on polarized light and LED chips cannot be controlled individually. The light loses about 57% of brightness through the upper and lower polarizers, the loss rate of light reaches 70% when passing through the color filter, and other losses are added, so that the utilization efficiency of the LCD display to the brightness of the backlight source is only 8% at most, namely 92% of energy can be wasted. Compared with LCD, the Mini LED adopts a large number of 50-200 μm LED chips, and can independently control the on-off of the LED chips. Therefore, the Mini LED has the advantage of low power consumption naturally, and the utilization efficiency of the Mini LED to the backlight source can reach 13% or even higher under the condition of displaying the same picture. And the higher the reflectivity of the backlight coating of the Mini LED, the higher the utilization efficiency of the backlight source.

The white ink plays an indispensable role in Mini LED backlight, and is used to coat on the LED chip to provide a uniform, high-brightness white light source, thereby ensuring color reproducibility and brightness of the display screen. Therefore, developing high-quality white ink for LEDs has important significance for popularization and application of Mini LED backlight technology.

At present, researchers often use a mixture of red, green and blue pigments, and add appropriate amounts of binders, solvents and other auxiliary materials, and prepare white ink compositions by mechanical stirring, dispersion and other processes. In addition, some researchers have attempted to use combinations of other pigments, such as yellow, violet, etc., to improve the color rendition of white light. However, the existing white ink generally has the problems of insufficient reflectivity, low light efficiency utilization rate, poor color stability, low luminous efficiency and the like. Accordingly, there is a need for further research and improvement of white inks to meet the demand for high quality white light sources for LED display screens.

Disclosure of Invention

The invention provides a white ink composition for an LED and a preparation method thereof, and the white ink composition is applied to Mini LED backlight coating, LED display, printed electronics and LED illumination, aiming at overcoming the defects that the white ink in the prior art is generally insufficient in reflectivity, low in light efficiency utilization rate, easy to settle after standing and storage, poor in viscosity uniformity, hard after solidification, easy to scratch, not ageing-resistant and easy to generate yellowing.

In order to achieve the aim of the invention, the invention is realized by the following technical scheme:

the white ink composition for the LED comprises the following components in parts by weight:

5-40 parts of epoxy resin;

0.01-20 parts of curing agent;

21.05-70 parts of inorganic filler;

0.1-3 parts of dispersing agent;

0.2-4 parts of leveling agent;

2.94-91.5 parts of diluent;

wherein the epoxy resin is any one or a combination of more of organosilicon modified epoxy resin, mixed epoxy resin, bisphenol A type phenolic epoxy resin and glycidyl ester type epoxy resin with the molecular weight of the epoxy resin less than 1000; the transmittance of the reaction product of the epoxy resin and the curing agent is not less than 99.0%, and more preferably, the transmittance of the reaction product of the epoxy resin and the curing agent is not less than 99.6%.

The invention carries out compound selection on various epoxy resins and curing agents with good stability at normal temperature, tests the transmittance of the cured products when other fillers and solvents are not added, the test sample plate is a common glass slide, the thickness of the cured coating is 1-2 mm, the width of the coating is 2cm, the length of the coating is 4cm, and the formula with the transmittance of more than 99.0% is screened. Thus, a white ink having a reflectance of 93% or more when the thickness of the integral adhesive layer formed was 50 μm and a reflectance of 94% or more when the thickness of the integral adhesive layer formed was 70 μm was obtained. Therefore, when the reflectivity is improved by more than 4%, compared with the traditional white ink, the thickness of the whole adhesive layer can be reduced to half of the original thickness, and the saving of raw materials is further realized to be more than 40% of the original thickness. Meanwhile, the inventor finds according to data test that when the reflectivity reaches more than 80%, the reflectivity is increased by one percentage point, so that the energy consumption is reduced by 0.83% for achieving the same brightness, the overall energy consumption is further reduced by 3.3-8% or more, and the light efficiency utilization rate is improved. In addition, on the premise of not reducing the thickness of the whole adhesive layer, the white ink can improve the light efficiency utilization rate by more than 3%, so that the whole display effect is improved more; and when the same light efficiency utilization rate is achieved, the service life of the whole device can be prolonged by more than 10 percent.

On the basis of the formula, the white ink product with the adhesive layer thickness of more than 94 percent, excellent anti-sedimentation performance, scratch resistance, aging resistance, durability and high reliability is finally formed by adopting the fillers such as titanium dioxide with different particle sizes and the specific proportion, matching with specific modified fumed silica and/or other anti-sedimentation agents, adding the dispersing agent with good dispersing effect on the powder, the leveling agent with good leveling performance and a proper amount of diluent with low viscosity and high purity (purity is more than 98 percent).

Wherein, the optical path schematic diagram in the cured high-transmittance adhesive layer is shown in figure 1, and the incident light L ₀ Emergent ray L _a +absorbed light L _b (the test substrate is proximate to the test surface and therefore does not take into account the reflection of light). At incident ray L ₀ At a certain time, the higher the transmittance of the adhesive layer is, the absorption L of the adhesive layer to light is shown _b The less the light is in the glue layer, the less the refraction loss of the light is, and the emergent light L _a The higher the outgoing light ray L _a The higher the glue layer, the higher the reflectivity after adding the highly reflective material.

After adding the highly reflective material, the schematic diagram of the white ink coating light path is shown in fig. 2: incident ray L ₀ At a certain time, the scattering and loss in the white ink coating prepared by the high-transmittance adhesive can be correspondingly reduced (compared with the coating with common transmittance), and the reflected light L _c Will rise, the reflectance will also become high (reflectance = reflected light L _c Incident ray L ₀ ) And the high-transmittance coating has the advantages that the light scattering and loss are reduced, and the service life of the corresponding coating is prolonged.

In addition, the existing white ink made of epoxy materials is high in hardness after being cured, so that the product formed by the white ink is extremely easy to scratch in the preparation and assembly processes, and the surface quality of the product is reduced. The inventor selects specific epoxy resin after continuous experiments, and matches proper curing agent and inorganic filler, so that the hardness of the cured product is about Shore D40, a certain hardness is maintained to reduce warpage, scraping is reduced to improve the yield of the product, and proper rigidity and toughness are maintained.

In addition, the epoxy resin has excellent adhesiveness, chemical resistance and heat resistance, and is suitable for application in high-temperature environments. And the epoxy resin can provide good electrical insulation performance, protect electronic devices from the external environment, and is widely applied to LCD display technology and LED backlight application. As disclosed in patent CN102757692B, a white ink composition of a thermosetting LED soft light strip plate is disclosed, which uses a flexible composition comprising a polyester resin, an acrylic resin, an epoxy resin as a main resin, and an amino resin as a curing agent, and the white ink prepared from the resin composition has good heat resistance but poor weather resistance and is liable to yellow upon irradiation with ultraviolet light. Wherein the epoxy resin is mainly bisphenol A type phenolic epoxy resin.

Phenolic epoxy resin has good temperature resistance, but the product is brittle, the adhesive force with a base material is reduced, the common bisphenol A epoxy resin has a linear structure, the structure of a crosslinked product is simple, the moisture and heat resistance of the crosslinked product are poor, and the reflectivity of the cured product is reduced by about 2.6 percent when the cured product is aged for 200 hours under double 85 conditions (85 ℃/85%RH); when aged for 1000 hours, the reflectance was reduced by about 5.5%. And the cured product has obvious yellowing in appearance, and is accompanied with the generation of coating cracks, so that the product is invalid. The bisphenol A type phenolic epoxy resin selected by the invention is prepared by comprehensively considering the performances of the two resins, carrying out chemical reaction on hydroxymethyl in the phenolic resin, hydroxyl and epoxy groups in the epoxy resin, carrying out chemical reaction on phenolic hydroxyl in the phenolic resin and epoxy groups in the epoxy resin, finally crosslinking into a complex multilayer body type structure to achieve the aim of improving the wet heat resistance, and then matching with organosilicon modified epoxy resin or mixed epoxy resin to form a high-transmittance formula, so that the cured multilayer body type structure is more compact, and the water-oxygen permeability is effectively reduced. Further testing the product, aging for 1000 hours under double 85 conditions can stably control the reflectivity to be reduced within 2%, and the appearance of the coating surface of the product is kept uniform.

On the other hand, since piezoelectric printing requires a severe requirement for the viscosity uniformity of the white ink material, the viscosity of the white ink material needs to be controlled to about 110 to 200cps with the addition of a large amount of reactive or/and non-reactive diluents. Under the requirement of low viscosity, the fillers such as titanium dioxide and the like contained in the polymer are extremely easy to agglomerate and sink. After the single-component ink product for piezoelectric printing prepared by the existing manufacturer is kept stand for 7-10 days, the upper-layer viscosity of the product can be reduced by more than 20% (the viscosity of the product tested by taking the storage center line of the product storage tank as the center point is called upper-layer viscosity), and the upper-layer viscosity of the product is reduced by more than 30% after the product is kept stand for 1 month. Even if stirring is performed mechanically or manually at a later stage, the filler dispersion is difficult to restore to the original state, further causing the reflectance of the product to decrease.

For the bi-component epoxy white ink, the steps of proportioning weighing and the like before use are complicated, and the service life of the proportioned product further influences the use of materials. After the materials are kept stand for 8-12 h, the viscosity of the materials is greatly increased, so that the materials cannot be used, and further the waste of the materials is caused. More importantly, the two-component epoxy white ink product needs to be cleaned regularly and timely in the use process so as to avoid the problems of needle blocking and the like.

The inventor discovers after further exploration that the viscosity of the upper layer of the single-component white ink product is controlled to be reduced within 7% in the process of standing and storing for 1 month, and the viscosity of the upper layer of the product is controlled to be reduced within 30% after standing and storing for 3 months by adopting specific modified fumed silica and/or other anti-settling agents for compounding use. Therefore, the viscosity uniformity of the white ink product in the standing storage process is effectively improved, the subsequent preparation process of the product is further promoted to be simpler, and the performance of the white ink product is effectively ensured. The modified fumed silica is obtained by modification of dichlorodimethylsilane, so that hydrophilic hydroxyl on the surface of the fumed silica reacts to form a silicon-oxygen bond. After the silica is added into an organic system, the bond energy of a silica bond and other carbon-carbon bonds is different, so that the silica can spontaneously aggregate, and filler particles are wrapped in the silica, thereby greatly improving the anti-sedimentation performance.

Preferably, the inorganic filler is any one or a combination of a plurality of titanium dioxide, barium sulfate and modified fumed silica; the average grain diameter of the titanium dioxide is 25-2000 nm, and the addition amount of the titanium dioxide is 20-55 parts by weight; the average grain diameter of the barium sulfate is 400-3000 nm, and the adding amount of the barium sulfate is 1-10 parts by weight; the average grain diameter of the modified fumed silica is 5-120 nm, and the addition amount of the modified fumed silica is 0.05-5 parts by weight.

The white degree of the white ink can be enhanced by selecting titanium dioxide, barium sulfate and modified fumed silica inorganic filler, the color of the base material is effectively covered, and the light transmission phenomenon is reduced, so that clear and bright images and display effects are provided. Meanwhile, the inorganic filler has higher refractive index, can effectively enhance the optical performance of the white ink coating, and further improves the contrast ratio and the image definition of the display. In addition, the inorganic filler has higher density and weight, can be uniformly distributed in the white ink, and effectively prevents precipitation and layering phenomena, thereby ensuring the uniformity of the white ink. And the stability of the white ink is improved, the sedimentation phenomenon is reduced, and the durability of the white ink are further improved.

Preferably, the epoxy resin is a combination of any one of organosilicon modified epoxy resin and mixed epoxy resin and phenolic epoxy resin;

the curing agent is a latent curing agent, preferably any one or a combination of a plurality of organic phosphorus derivatives, microcapsules, polyamine salts, imidazole adducts and metal complexes.

The mixed epoxy resin, the organosilicon modified epoxy resin, the bisphenol A type phenolic epoxy resin and the glycidyl ester epoxy resin have good ultraviolet resistance and light resistance stability, and effectively prevent fading. Meanwhile, the epoxy resin has higher heat resistance, can keep stability in a high-temperature environment, and effectively avoids losing color or deforming due to high temperature. In addition, the epoxy resin has good chemical corrosion resistance and contributes to prolonging the service life of the white ink. And the epoxy resin has excellent adhesiveness, and is beneficial to improving the stability and durability of the white ink in the LED backlight.

Further preferably, the curing agent is any one or a combination of a plurality of organic phosphorus derivatives, imidazole adducts and microcapsules.

The organic phosphorus derivative, the microcapsule, the polyamine salt, the imidazole adduct and the metal complex latent curing agent have high adaptability, can be compatible with each component in the white ink, and can generate curing reaction on different substrate surfaces. Meanwhile, the curing reaction rate is high, and the production efficiency is improved. In addition, the white ink using the latent curing agent has higher transparency and contributes to providing a clearer and more colorful display effect. In addition, the white ink cured by the latent curing agent has good durability, is not easily influenced by light, moisture, temperature and other environmental factors, and further prolongs the service life of the LED backlight coating.

Preferably, the curing agent comprises 0.01-3 parts of organic phosphorus derivative or 3-20 parts of microcapsule according to parts by weight.

Preferably, the viscosity of the epoxy resin is 300-200000 cps at 25 ℃, and the epoxy value is 0.34-1.05.

The epoxy resin with smaller molecular weight can provide better gluing effect and is helpful for improving the adhesive force of the white ink on the substrate. When the molecular weight of the epoxy resin is more than or equal to 1000 and the viscosity of the epoxy resin at 25 ℃ is higher than 200000cps, the viscosity of the white ink is easy to be too high, the fluidity is reduced, and the coating is not easy to be carried out. Thereby causing coating unevenness and surface defects, further resulting in reduced production efficiency and coating quality. When the viscosity of the epoxy resin is less than 300cps at 25 ℃, the white ink tends to be too thin, the adhesion on the substrate is insufficient, and it is difficult to provide sufficient surface protection to the substrate.

In addition, when the epoxy value of the epoxy resin is less than 0.34, the curing reaction of the white ink is easily affected, resulting in a decrease in hardness and chemical resistance after the white ink is cured. When the epoxy value of the epoxy resin is higher than 1.05, the hardness of the white ink after being cured is easily too high, the flexibility is lost, and the impact resistance of the coating is further reduced.

As a further preference, the epoxy resin has a color value of < 100Hazen.

Still more preferably, the epoxy resin has a color value of < 40Hazen.

When the chromaticity value of the epoxy resin is less than 100Hazen, yellowing or darkening of the epoxy resin can be effectively avoided, and the transparency of the epoxy resin can be enhanced. Meanwhile, the lower chromaticity value enables the white part of the LED backlight to be purer and brighter, and yellow or gray impurities are effectively reduced. The LED backlight module is beneficial to improving the appearance quality of products, enhancing the attractiveness and further improving the color reproducibility and the image definition of the LED backlight.

Still more preferably, the silicone modified epoxy resin has a viscosity of 300 to 500cps at 25 ℃, a molecular weight of 697, and an epoxy value of 0.57.

Still more preferably, the bisphenol A type novolac epoxy resin has a viscosity of 1100 to 1700 at 52 ℃ and an epoxy value of 0.5 to 0.6.

Still more preferably, the viscosity of the mixed epoxy resin is 600 to 900cps at 25 ℃ and the epoxy equivalent is 160 to 180.

Preferably, the dispersing agent is any one or a combination of more of polyether modified organic silicon, urea-formaldehyde resin and phosphate modified acrylic acid.

As a further preference, the dispersant is BYK-110.

The polyether modified organosilicon, urea-formaldehyde resin and phosphate modified acrylic dispersing agent can effectively disperse pigment particles, ensure that the pigment particles are uniformly distributed in the white ink, and effectively avoid the phenomena of agglomeration, sedimentation and the like of the pigment, thereby improving the color uniformity and the display effect of the white ink. The addition of the dispersant also helps to adjust the color of the white ink to achieve the desired color brightness and purity while maintaining color stability. In addition, the dispersing agent plays a role in adjusting viscosity in the white ink, and is helpful for controlling the fluidity of the white ink so as to ensure good coating performance and further improve the processing performance and printing quality of the white ink. In addition, the dispersing agent can effectively enhance the weather resistance of the white ink, so that the white ink can still keep stable color and excellent performance under long-time use and exposure, and the service life of electronic devices such as LED backlight coatings and the like is further prolonged.

Preferably, the leveling agent is any one or a combination of multiple polyether modified organic silicon, urea-formaldehyde resin and phosphate modified acrylic acid.

As a further preferred, the leveling agent is basf leveling agent (Efka SL 3288).

The polyether modified organosilicon, urea-formaldehyde resin and phosphate modified acrylic leveling agent are beneficial to improving the surface smoothness of the formed LED backlight coating, so that the smoothness of the LED backlight coating is improved, and the definition and the image quality of a display are further improved. Meanwhile, the addition of the leveling agent is beneficial to enhancing the fluidity and the distribution uniformity of the white ink, so that the formation of bubbles and other defects is effectively prevented, and the reliability and the service life of the display are further improved.

Preferably, the diluent includes an inactive diluent, and the inactive diluent is added in an amount of 0 to 40 parts by weight.

Further preferably, the inert diluent is any one or a combination of more than one of esters, ketones, amines and alcohols.

Still more preferably, the non-reactive diluent has a boiling point > 80 ℃ and a saturated vapor pressure less than or equal to 0.5kpa at 25 ℃.

Still more preferably, the inactive diluent is any one or a combination of two of propylene glycol methyl ether acetate and cyclohexanone.

Esters, ketones, amines, and alcohol inert diluents can change the viscosity of the white ink and increase the fluidity of the white ink, thereby promoting easier application to a substrate. Helps to ensure that the white ink is evenly distributed over the entire substrate surface, resulting in a better display. Meanwhile, the inactive diluent can effectively prevent each component in the white ink from agglomerating or settling, and is beneficial to improving the uniform stability of the white ink, so that the service life of the white ink is prolonged. In addition, the non-reactive diluent may adjust optical characteristics of the white ink, such as transparency, luminous effect, etc. Further promoting higher brightness and contrast in LCD screen or LED backlight applications.

Preferably, the diluent comprises a reactive diluent, and the addition amount of the reactive diluent is 2.94-51.5 parts by weight. As a further preferred option, the reactive diluent is any one or more of 2-ethyl-hexyl glycidyl ether, styrene oxide, polyethylene glycol diglycidyl ether, diglycidyl aniline.

Still more preferably, the reactive diluent is C ₁₂ ～C ₁₄ Alkyl Glycidyl Ethers (AGEs).

The 2-ethyl-hexyl glycidyl ether, styrene oxide, polyethylene glycol diglycidyl ether, diglycidyl ether and diglycidyl aniline active diluents are beneficial to reducing the viscosity of the white ink, thereby improving the fluidity of the white ink and helping the white ink to be uniformly coated on the surface of a substrate. Meanwhile, the reactive diluent is favorable for accelerating volatilization and drying speed of the white ink and promoting rapid solidification of the white ink, so that the production period is effectively shortened. In addition, the addition of the reactive diluent can effectively improve the adhesion between the white ink and the substrate, and promote the white ink to be firmly adhered to the surface of the substrate, thereby improving the durability of the white ink. And different reactive diluents can also change the color shade and transparency of the white ink, so as to meet the requirements of different applications, such as adjusting the brightness, the color tone and the like of the white ink.

Preferably, the diluent is added in an amount of 10 to 40% by mass of the total mass of the white ink composition for LED.

Further preferably, the storage condition of the white ink composition for an LED is any one of temperatures of-20 to 50 ℃.

As a further preferred aspect, the curing conditions of the white ink composition for LED are:

The curing temperature is any one of 80-170 ℃, and the preferable curing reaction time is any one of 3-80 min.

The preparation method of the white ink composition for the LED comprises the following steps:

(S.1) weighing epoxy resin, and stirring at a high speed to obtain a stirring material I;

(S.2) heating and stirring the stirring material I and the curing agent obtained in the step (S.1) to obtain a stirring material II;

(S.3) adding inorganic filler, dispersant and flatting agent into the stirring material II obtained in the step (S.2) and mixing and stirring to obtain a stirring material III;

(S.4) grinding the stirring material III obtained in the step (S.3) to obtain a stirring material IV;

(S.5) adding a diluent into the stirring material IV obtained in the step (S.4) and mixing and stirring to obtain a stirring material V;

(S.6) filtering and standing the stirring material V obtained in the step (S.5) to obtain the white ink VI for the LED.

As a further preferred, the heating conditions in step (s.2) are: the heating temperature is any temperature less than or equal to 60 ℃.

As a further preferred option, when the curing agent in step (s.2) is a microcapsule curing agent, the heating reaction is optionally not performed.

The white ink composition for LEDs or the preparation method of the white ink composition for LEDs is applied to Mini LED backlight coating, LED display, printed electronics, LED illumination and piezoelectric printing.

Therefore, the invention has the following beneficial effects:

(1) When the reflectivity of the white ink is improved by more than 4%, compared with the traditional white ink, the thickness of the whole adhesive layer can be reduced to half of the original thickness, so that the raw materials can be further saved by more than 40%;

(2) On the premise of not reducing the thickness of the whole adhesive layer, the white ink provided by the invention has the light transmittance of more than 99.6%, and the light efficiency utilization rate can be improved by more than 3%, so that the whole display effect is improved more; when the same light efficiency utilization rate is achieved, the service life of the whole device can be prolonged by more than 10 percent;

(3) According to the invention, titanium dioxide with different particle sizes and specific proportions are adopted, modified fumed silica and/or other anti-settling agents are matched, and a dispersing agent, a leveling agent and a diluting agent are added, so that a white ink product with the adhesive layer thickness of more than 94%, excellent anti-settling performance, scratch resistance, ageing resistance, durability and high reliability is finally formed; (4) The invention adopts specific modified fumed silica and/or other anti-settling agents for compounding use, effectively improves the viscosity uniformity of the white ink in the standing storage process, and further prolongs the storage pot life of the white ink.

Drawings

Fig. 1 is a schematic diagram of the optical path in a cured high-transmittance adhesive layer.

Fig. 2 is a schematic diagram of the optical path of a white ink coating after addition of highly reflective material.

FIGS. 3 to 5 are graphs showing the upper layer viscosity change of the white inks prepared in examples 1 to 9 and comparative examples 1 to 18.

FIGS. 6 to 7 are graphs showing changes in reflectance when the white inks prepared in examples 1 to 9 and comparative examples 1 to 18 were aged at 85℃under 85% RH.

FIG. 8 is a graph of a sample of yellowing cracking of a white ink after aging at 85℃under 85% RH for 1000 hours.

Fig. 9 is a diagram of a sample showing water waves in appearance.

FIG. 10 is a sample view of the presence of a splice seam during printing.

Fig. 11 is a diagram of a printed sample.

Detailed Description

The invention is further described below with reference to the drawings and specific examples. Those of ordinary skill in the art will be able to implement the invention based on these descriptions. In addition, the embodiments of the present invention referred to in the following description are typically only some, but not all, embodiments of the present invention. Therefore, all other embodiments, which can be made by one of ordinary skill in the art without undue burden, are intended to be within the scope of the present invention, based on the embodiments of the present invention.

Example 1

In this example, a white ink composition for LED is provided.

epoxy resin: 25 parts of organosilicon modified epoxy resin (CTS 101) and 8 parts of phenolic epoxy resin (F51);

curing agent: 0.3 part of curing agent 1 (organophosphorus derivative, ICAM-8412);

inorganic filler:

3 parts of titanium dioxide powder 1 (JC-TF 25 with average grain diameter of 20-30 nm);

17 parts of titanium dioxide powder 2 (CR 60-2 with the average particle size of 210 nm);

9 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm);

5 parts of titanium dioxide powder 4 (R960, average particle size is 500 nm);

2.5 parts of barium sulfate powder (HA 08, average particle size of 920 nm);

1 part of modified fumed silica powder (R972, average particle diameter of 16 nm);

dispersing agent: 0.9 part of BYK-110 dispersing agent;

leveling agent: 1.3 parts of Pasteur leveling agent (Efka SL 3288);

a diluent: 18 parts of diluent 1 (propylene glycol methyl ether acetate) and 10 parts of diluent 2 (AGE). Wherein the addition amount of the diluent is 27.72% of the total mass of the white ink composition for LED.

The embodiment also provides a preparation method of the white ink composition for the LED.

A method for preparing a white ink composition for LEDs, comprising the steps of:

(S.1) weighing 25 parts of organosilicon modified epoxy resin (CTS 101) and 8 parts of phenolic epoxy resin (F51), placing the mixture in a stirring tank, and stirring for 2 times under the condition of 160 rpm for 3min to obtain a stirring material I;

(S.2) to the stirred material I obtained in the step (S.1), 0.3 part of a curing agent 1 (an organic phosphorus derivative, ICAM-8412) was added, and a particle was placed in a stirring tank, and the stirred material I was obtained by hermetically placing the stirred material in a water bath at 45℃and hermetically stirring the stirred material for 0.5 hour at 1000 rpm. CoolingThen 3.5 parts of stirring material II is taken and solidified on a glass slide to prepare colorless transparent templates (the number of the templates is more than or equal to 3) with the thickness of 1-2 mm, the width of 2cm and the length of 4cm, the transmittance of different positions of different templates is tested, and then the average value is calculated to obtain the final transmittance before adding powder (transmittance=L) _a /L ₀ )；

(S.3) to the stirred material II obtained in the step (S.2), 3 parts of titanium white powder 1 (JC-TF 25, average particle diameter of 20 to 30 nm), 17 parts of titanium white powder 2 (CR 60-2, average particle diameter of 210 nm), 9 parts of titanium white powder 3 (RT 06, average particle diameter of 360 nm), 5 parts of titanium white powder 4 (R960, average particle diameter of 500 nm), 2.5 parts of barium sulfate powder (HA 08, average particle diameter of 920 nm), 1 part of modified fumed silica powder (R972, average particle diameter of 16 nm), 0.9 part of dispersant BYK-110 and 1.3 parts of Basoff leveling agent (Efka SL 3288) were added, and stirred for 1 time under the condition of 160 rpm for 3min in a mixing machine after sealing. Stirring for 1 time, taking out, manually stirring, scraping the solid at the edge into colloid, stirring for 1 time under the condition of 160 rpm for 3min after scraping, and obtaining a stirring material III;

(S.4) taking the stirring material III obtained in the step (S.3), and grinding the stirring material III in a three-roller stirrer back and forth for 3-5 times to ensure that the discharge grain diameter is less than or equal to 5 mu m, thereby obtaining a stirring material IV;

(S.5) based on the yield of stirred material IV obtained by three-roll grinding, the addition of 18 parts of diluent 1 (propylene glycol methyl ether acetate) and 10 parts of diluent 2 (C) ₁₂ ～C ₁₄ Alkyl glycidyl ether, AGE) in the mixture, after sealing, stirring 2 times in a mixing machine at 160 rpm for 3min to obtain a stirring material V;

and (S.6) taking the stirring material V obtained in the step (S.5), pumping the stirring material V into a filter provided with a filter element (with a filter diameter of 10 mu m) through an air diaphragm pump, filtering, standing the filtered product for 1h, and finally, completing natural defoaming to obtain the white ink VI for the LED, wherein the viscosity of the white ink is 110-200 mpa.s (specific numerical values are generally filled in) at 25 ℃. The white ink VI is solidified on a common glass slide to obtain a white test template (the number of the template is more than or equal to 3) with the width of 2cm and the length of 4cm, the reflectivity of the white ink VI for the LED at the thickness of 70 mu m is tested, and then the average value is calculated to obtain the final reflection after adding powderReflectance (reflectance=l) _c /L ₀ )。

Example 2

This embodiment differs from embodiment 1 in that:

in this example, a white ink composition for LED was provided, in which 10 parts by weight of "novolac epoxy resin (F51), 22 parts by weight of hybrid epoxy resin (LX 8756)," 25 parts by weight of silicone modified epoxy resin (CTS 101), 8 parts by weight of novolac epoxy resin (F51) "were used; diluent 1 (propylene glycol methyl ether acetate) 18 parts, diluent 2 (AGE) 10 parts were "replaced" with diluent 1 (propylene glycol methyl ether acetate) 15 parts, diluent 2 (AGE) 13 parts. The other components are the same as those in example 1. Wherein the addition amount of the diluent is 28% of the total mass of the white ink composition for LED.

Example 3

This embodiment differs from embodiment 1 in that:

in this example, a white ink composition for LED is provided in which "25 parts of silicone modified epoxy resin (CTS 101)" is replaced with "24 parts of silicone modified epoxy resin (CTS 101)" in parts by weight; 0.3 part of curing agent 1 (organophosphorus derivative, ICAM-8412) was replaced with 5 parts of curing agent 2 (microcapsule HX-3742); 3 parts of titanium dioxide powder 1 (JC-TF 25, average grain diameter of 20-30 nm) are replaced by 33 parts of titanium dioxide powder 2 (CR 60-2, average grain diameter of 210 nm); 17 parts of titanium dioxide powder 2 (CR 60-2 with the average particle size of 210 nm); 9 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm); 5 parts of titanium dioxide powder 4 (R960, average particle size is 500 nm), namely, titanium dioxide powder 1, titanium dioxide powder 3 and titanium dioxide powder 4 are not added; diluent 1 (propylene glycol methyl ether acetate) 18 parts, diluent 2 (AGE) 10 parts were "replaced" with diluent 1 (propylene glycol methyl ether acetate) 15 parts, diluent 2 (AGE) 13 parts. The other components are the same as those in example 1. Wherein the addition amount of the diluent is 27% of the total mass of the white ink composition for an LED.

Example 4

This embodiment differs from embodiment 1 in that:

The present example provides a white ink composition for LEDs, wherein, by weight, 3 parts of titanium dioxide powder 1 (JC-TF 25, average particle diameter of 20-30 nm) is replaced by 33 parts of titanium dioxide powder 3 (RT 06, average particle diameter of 360 nm); 17 parts of titanium dioxide powder 2 (CR 60-2 with the average particle size of 210 nm); 9 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm); 5 parts of titanium dioxide powder 4 (R960, average particle size is 500 nm), namely, titanium dioxide powder 1, titanium dioxide powder 2 and titanium dioxide powder 4 are not added; diluent 1 (propylene glycol methyl ether acetate) 18 parts, diluent 2 (AGE) 10 parts were "replaced" with diluent 1 (propylene glycol methyl ether acetate) 15 parts, diluent 2 (AGE) 13 parts. The other components are the same as those in example 1. Wherein the addition amount of the diluent is 28% of the total mass of the white ink composition for LED.

Example 5

This embodiment differs from embodiment 1 in that:

in this example, a white ink composition for LED was provided, in which 14 parts by weight of "novolac epoxy resin (F51), 23 parts by weight of hybrid epoxy resin (LX 8756)," 25 parts by weight of silicone modified epoxy resin (CTS 101), 8 parts by weight of novolac epoxy resin (F51) "were used; 16 parts of titanium dioxide powder 2 (CR 60-2 with the average particle diameter of 210 nm) is used; 17 parts of titanium dioxide powder 3 (RT 06, average particle size of 360 nm) and 8 parts of 'replacement' titanium dioxide powder 2 (CR 60-2, average particle size of 210 nm); 9 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm); 18 parts of diluent 1 (propylene glycol methyl ether acetate), 11 parts of diluent 2 (AGE) and 10 parts of diluent 2 (AGE) are replaced with 18 parts of diluent 1 (propylene glycol methyl ether acetate). The other components are the same as those in example 1. Wherein the addition amount of the diluent is 27.9% of the total mass of the white ink composition for LED.

Example 6

This embodiment differs from embodiment 1 in that:

in this example, a white ink composition for LED was provided, in which 14 parts by weight of "novolac epoxy resin (F51), 22 parts by weight of hybrid epoxy resin (LX 8756)," 25 parts by weight of silicone modified epoxy resin (CTS 101), 8 parts by weight of novolac epoxy resin (F51) "were used; 0.3 part of curing agent 1 (organophosphorus derivative, ICAM-8412) was replaced with 5 parts of curing agent 2 (microcapsule HX-3742); 16 parts of titanium dioxide powder 2 (CR 60-2 with the average particle diameter of 210 nm) is used; 17 parts of titanium dioxide powder 3 (RT 06, average particle size of 360 nm) and 8 parts of 'replacement' titanium dioxide powder 2 (CR 60-2, average particle size of 210 nm); 9 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm); 18 parts of diluent 1 (propylene glycol methyl ether acetate), 11 parts of diluent 2 (AGE) and 10 parts of diluent 2 (AGE) are replaced with 18 parts of diluent 1 (propylene glycol methyl ether acetate). The other components are the same as those in example 1. Wherein the addition amount of the diluent is 26.9% of the total mass of the white ink composition for LED.

Example 7

This embodiment differs from embodiment 1 in that:

in this example, there is provided a white ink composition for LED, wherein "3 parts of curing agent 1 (organophosphorus derivative ICAM-8412) is used in place of 0.3 parts of curing agent 1 (organophosphorus derivative ICAM-8412) in parts by weight"; 3 parts of titanium dioxide powder 1 (JC-TF 25 with average grain diameter of 20-30 nm); 17 parts of titanium dioxide powder 2 (CR 60-2 with the average grain diameter of 210 nm) and 3 parts of titanium dioxide powder 1 (JC-TF 25 with the average grain diameter of 20-30 nm) which are replaced by the titanium dioxide powder; 17 parts of titanium dioxide powder 2 (CR 60-2 with the average particle size of 210 nm); 9 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm); 5 parts of titanium dioxide powder 4 (R960, average particle size is 500 nm), namely, titanium dioxide powder 3 and titanium dioxide powder 4 are not added; 1 part of the modified fumed silica powder (R972, average particle diameter: 16 nm) was replaced with 0 part of the modified fumed silica powder (R972, average particle diameter: 16 nm), i.e., no modified fumed silica powder was added. The other components are the same as those in example 1. Wherein the addition amount of the diluent is 32.4% of the total mass of the white ink composition for LED.

Example 8

This embodiment differs from embodiment 1 in that:

the embodiment provides a white ink composition for LEDs, which comprises the following components in parts by weight:

epoxy resin: 3 parts of organosilicon modified epoxy resin (CTS 101) and 2 parts of phenolic epoxy resin (F51);

curing agent: 0.01 part of curing agent 1 (organophosphorus derivative, ICAM-8412);

inorganic filler:

2 parts of titanium dioxide powder 1 (JC-TF 25 with average grain diameter of 20-30 nm);

8 parts of titanium dioxide powder 2 (CR 60-2 with the average particle size of 210 nm);

6 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm);

4 parts of titanium dioxide powder 4 (R960, average particle size is 500 nm);

1 part of barium sulfate powder (HA 08, average grain size is 920 nm);

0.05 part of modified fumed silica powder (R972, average particle diameter 16 nm);

dispersing agent: 0.1 part of BYK-110 dispersing agent;

leveling agent: 0.2 part of basf leveling agent (Efka SL 3288);

a diluent: 0 part of diluent 1 (propylene glycol methyl ether acetate) and 2.94 parts of diluent 2 (AGE). The other components are the same as those in example 1. Wherein the addition amount of the diluent is 10% of the total mass of the white ink composition for LED.

Example 9

This embodiment differs from embodiment 1 in that:

Epoxy resin: 32 parts of organosilicon modified epoxy resin (CTS 101) and 8 parts of phenolic epoxy resin (F51);

curing agent: 20 parts of curing agent 2 (microcapsule HX-3742);

inorganic filler:

8 parts of titanium dioxide powder 1 (JC-TF 25, average grain size is 20-30 nm);

24 parts of titanium dioxide powder 2 (CR 60-2 with the average particle size of 210 nm);

15 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm);

8 parts of titanium dioxide powder 4 (R960, average particle size is 500 nm);

10 parts of barium sulfate powder (HA 08, average particle size of 920 nm);

5 parts of modified fumed silica powder (R972, average particle diameter 16 nm);

dispersing agent: 3 parts of BYK-110 dispersing agent;

leveling agent: 4 parts of basf leveling agent (Efka SL 3288);

a diluent: 40 parts of diluent 1 (propylene glycol methyl ether acetate) and 51.5 parts of diluent 2 (AGE). The other components are the same as those in example 1. Wherein the addition amount of the diluent is 40% of the total mass of the white ink composition for LED.

Comparative example 1

The difference between this comparative example and example 1 is that:

in this comparative example, a white ink composition for LED was provided in which 25 parts of silicone modified epoxy resin (CTS 101) and 8 parts of novolac epoxy resin (F51) were replaced with 33 parts of "bisphenol a epoxy resin (E51)" in parts by weight; diluent 1 (propylene glycol methyl ether acetate) 18 parts, diluent 2 (AGE) 10 parts were "replaced" with diluent 1 (propylene glycol methyl ether acetate) 15 parts, diluent 2 (AGE) 13 parts. The other components are the same as those in example 1.

Comparative example 2

The difference between this comparative example and example 1 is that:

in this comparative example, a white ink composition for LED was provided in which 25 parts of silicone modified epoxy resin (CTS 101) and 8 parts of novolac epoxy resin (F51) were replaced with 33 parts of "bisphenol a epoxy resin (E51)" in parts by weight; 3 parts of titanium dioxide powder 1 (JC-TF 25, average grain diameter of 20-30 nm) are replaced by 34 parts of titanium dioxide powder 1 (JC-TF 25, average grain diameter of 20-30 nm); 17 parts of titanium dioxide powder 2 (CR 60-2 with the average particle size of 210 nm); 9 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm); 5 parts of titanium dioxide powder 4 (R960, average particle size is 500 nm), namely, titanium dioxide powder 2, titanium dioxide powder 3 and titanium dioxide powder 4 are not added; 0 part of modified fumed silica powder (R972, average particle diameter is 16 nm) is used for replacing 1 part of modified fumed silica powder (R972, average particle diameter is 16 nm), namely, the modified fumed silica powder is not added; diluent 1 (propylene glycol methyl ether acetate) 18 parts, diluent 2 (AGE) 10 parts were "replaced" with diluent 1 (propylene glycol methyl ether acetate) 15 parts, diluent 2 (AGE) 13 parts. The other components are the same as those in example 1.

Comparative example 3

The difference between this comparative example and example 1 is that:

In this comparative example, a white ink composition for LED was provided in which 25 parts of silicone modified epoxy resin (CTS 101) and 8 parts of novolac epoxy resin (F51) were replaced with 25 parts of bisphenol a epoxy resin (E51) and 8 parts of novolac epoxy resin (F51) in parts by weight. The other components are the same as those in example 1.

Comparative example 4

The difference between this comparative example and example 1 is that:

in this comparative example, there is provided a white ink composition for LED, wherein 2.5 parts of "barium sulfate powder (HA 08, average particle diameter: 920 nm)" is replaced with 0 part of "barium sulfate powder (HA 08, average particle diameter: 920 nm)" in parts by weight, that is, no barium sulfate powder is added. The other components are the same as those in example 1.

Comparative example 5

The difference between this comparative example and example 1 is that:

in this comparative example, a white ink composition for LED was provided in which 2.5 parts by weight of "silicone-modified epoxy resin (CTS 101), 1.5 parts by weight of phenolic epoxy resin (F51) were" replaced "with 25 parts by weight of" silicone-modified epoxy resin (CTS 101), 8 parts by weight of phenolic epoxy resin (F51). The other components are the same as those in example 1.

Comparative example 6

The difference between this comparative example and example 1 is that:

in this comparative example, a white ink composition for LED was provided in which 37 parts by weight of "silicone modified epoxy resin (CTS 101), 8 parts by weight of phenolic epoxy resin (F51) were replaced with" 25 parts by weight of "silicone modified epoxy resin (CTS 101), 8 parts by weight of phenolic epoxy resin (F51). The other components are the same as those in example 1.

Comparative example 7

The difference between this comparative example and example 1 is that:

the comparative example provides a white ink composition for LEDs, wherein 1.5 parts of titanium dioxide powder 1 (JC-TF 25, average particle size of 20-30 nm) is used in parts by weight; 9 parts of titanium dioxide powder 2 (CR 60-2 with the average particle size of 210 nm); 4 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm); 2.5 parts of titanium dioxide powder 4 (R960, average grain diameter is 500 nm) and 3 parts of titanium dioxide powder 1 (JC-TF 25, average grain diameter is 20-30 nm) which are replaced by the titanium dioxide powder; 17 parts of titanium dioxide powder 2 (CR 60-2 with the average particle size of 210 nm); 9 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm); titanium pigment powder 4 (R960, average particle diameter 500 nm) 5 parts. The other components are the same as those in example 1.

Comparative example 8

The difference between this comparative example and example 1 is that:

the comparative example provides a white ink composition for LEDs, wherein 9 parts of titanium dioxide powder 1 (JC-TF 25, average particle size of 20-30 nm) is used in parts by weight; 31 parts of titanium dioxide powder 2 (CR 60-2 with the average particle size of 210 nm); 25 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm); 10 parts of titanium dioxide powder 4 (R960, average particle size of 500 nm) and 3 parts of titanium dioxide powder 1 (JC-TF 25, average particle size of 20-30 nm) are replaced; 17 parts of titanium dioxide powder 2 (CR 60-2 with the average particle size of 210 nm); 9 parts of titanium dioxide powder 3 (RT 06, average grain diameter is 360 nm); titanium pigment powder 4 (R960, average particle diameter 500 nm) 5 parts. The other components are the same as those in example 1.

Comparative example 9

The difference between this comparative example and example 1 is that:

in this comparative example, there is provided a white ink composition for LED, in which 2.5 parts of "barium sulfate powder (HA 08, average particle diameter: 920 nm) was replaced" with 0.5 part of "barium sulfate powder (HA 08, average particle diameter: 920 nm) in parts by weight. The other components are the same as those in example 1.

Comparative example 10

The difference between this comparative example and example 1 is that:

in this comparative example, a white ink composition for LED was provided in which 2.5 parts of "barium sulfate powder (HA 08, average particle diameter: 920 nm) was replaced with 15 parts of" barium sulfate powder (HA 08, average particle diameter: 920 nm) in parts by weight. The other components are the same as those in example 1.

Comparative example 11

The difference between this comparative example and example 1 is that:

in this comparative example, there is provided a white ink composition for an LED, in which 1 part of a modified fumed silica powder (R972, average particle diameter 16 nm) is replaced with 0.03 part of a modified fumed silica powder (R972, average particle diameter 16 nm) in parts by weight. The other components are the same as those in example 1.

Comparative example 12

The difference between this comparative example and example 1 is that:

in this comparative example, there is provided a white ink composition for an LED, in which 10 parts by weight of "modified fumed silica powder (R972, average particle diameter 16 nm)" is replaced with 1 part by weight of "modified fumed silica powder (R972, average particle diameter 16 nm)". The other components are the same as those in example 1.

Comparative example 13

The difference between this comparative example and example 1 is that:

in this comparative example, there is provided a white ink composition for LED, wherein, in parts by weight, 0 part of "diluent 1 (propylene glycol methyl ether acetate), 2.5 parts of" diluent 2 (AGE) "are substituted for" 18 parts of "diluent 1 (propylene glycol methyl ether acetate), 10 parts of" diluent 2 (AGE) ". Namely, diluent 1 (propylene glycol methyl ether acetate) was not added. The other components are the same as those in example 1.

Comparative example 14

The difference between this comparative example and example 1 is that:

in this comparative example, a white ink composition for LED was provided in which 45 parts by weight of "diluent 1 (propylene glycol methyl ether acetate), 55 parts by weight of" diluent 2 (AGE) "were substituted for 18 parts by weight of" diluent 1 (propylene glycol methyl ether acetate) and 10 parts by weight of "diluent 2 (AGE)". The other components are the same as those in example 1.

Comparative example 15

The difference between this comparative example and example 1 is that:

in this comparative example, a white ink composition for LEDs was provided in which 0.9 parts of "BYK-110 dispersant" was replaced with 0.05 parts of "BYK-110 dispersant" in parts by weight. The other components are the same as those in example 1.

Comparative example 16

The difference between this comparative example and example 1 is that:

in this comparative example, a white ink composition for LEDs was provided in which 0.9 part of the BYK-110 dispersant was replaced with 4 parts of the BYK-110 dispersant in parts by weight. The other components are the same as those in example 1.

Comparative example 17

The difference between this comparative example and example 1 is that:

in this comparative example, there is provided a white ink composition for LED in which 0.1 part by weight of "basf leveling agent (Efka SL 3288)" was replaced with "basf leveling agent (Efka SL 3288)" 1.3 parts by weight. The other components are the same as those in example 1.

Comparative example 18

The difference between this comparative example and example 1 is that:

in this comparative example, there is provided a white ink composition for LED in which 1.3 parts of the "basf leveling agent (Efka SL 3288) was replaced with 5 parts of the" basf leveling agent (Efka SL 3288) "in parts by weight. The other components are the same as those in example 1.

[ Performance test ]

Different white inks for LED were prepared according to the formulations and the preparation methods in examples 1 to 9 and comparative examples 1 to 18, respectively, and were used as performance test samples. And (3) standing the test samples before curing, storing the test samples, testing and recording initial viscosity, wherein each sample is prepared into 3 parts with the same amount, the first standing sample is used for testing the upper-layer viscosity at 168 hours, the second standing sample is used for testing the upper-layer viscosity at 720 hours, and the third standing sample is used for testing the upper-layer viscosity at 2160 hours. The test results are shown in table 1 below. The upper layer viscosity changes of the white inks prepared in examples 1 to 9 and comparative examples 1 to 18 are shown in FIGS. 3 to 5.

TABLE 1

The glass substrate was subjected to a plasma 100s treatment (argon, 40psi, 200W). The white inks prepared according to the formulations and preparation methods of examples 1 to 9 and comparative examples 1 to 18 were respectively printed on the treated glass substrates by piezoelectric printing, cured in an oven at 150℃for 60 minutes, observed for appearance and tested for the pre-powder transmittance, the post-powder reflectance, the post-aging reflectance at 85 ℃/85% RH for 200 hours and the post-aging reflectance at 85 ℃/85% RH for 1000 hours, respectively, and square blocks of 3cm 1cm were prepared under the same curing conditions to measure Shore D hardness. Wherein the reflectivity test equipment is a color spectrum DS-700D spectrocolorimeter, and the test results are shown in the following table 2. The reflectance changes when the white inks prepared in examples 1 to 9 and comparative examples 1 to 18 were aged at 85℃under 85% RH are shown in FIGS. 6 to 7. FIG. 8 is a graph of a sample of yellowing cracking of a white ink after aging at 85℃under 85% RH for 1000 hours. Fig. 9 is a diagram of a sample showing water waves in appearance. FIG. 10 is a sample view of the presence of a splice seam during printing. Fig. 11 is a diagram of a printed sample.

TABLE 2

From tables 1 to 2 and the data analysis in fig. 3 to 11, it can be seen that: the addition of the modified fumed silica powder in examples 1 to 6 showed a significant decrease in the viscosity value of the upper layer of the white ink as compared with the non-addition in example 7 and comparative example 2, indicating that the addition of the modified fumed silica powder effectively improved the anti-settling effect of the white ink. Too small or too large amounts of the additives in comparative examples 11 and 12 also affect the upper viscosity value of the white ink. When CTS-101, F51 and LX8756 are used for matching (examples 1-9), the transmittance of the adhesive layer is obviously improved, the improvement of the reflectivity is also facilitated, and the overall reflectivity is obviously improved after titanium dioxide powder with different particle sizes is used. And when CTS-101 and F51 and LX8756 are used for the formulation (examples 1 to 9), the hardness of the white ink after curing can be effectively reduced as compared with E51 (comparative examples 1 to 3). And when CTS-101, F51 and LX8756 are used for matching (examples 1-9), compared with E51 (such as comparative examples 1-3), the ageing performance of the white ink under the condition of 85 ℃/85% RH can be effectively improved.

From examples 3 to 7 and comparative examples 2, 7 and 8, it is known that the addition of titanium dioxide powder with different particle diameters and proportions can effectively improve the stability of the white ink, reduce the sedimentation phenomenon, and simultaneously effectively enhance the optical performance of the white ink coating. From example 1, comparative examples 4, 9, and 10, it is understood that the addition and the addition amount of barium sulfate powder also affect the reflectance and the anti-settling property of the white ink. As is clear from examples 1 and comparative examples 13 and 14, the non-reactive diluent can change the viscosity of the white ink, increase the fluidity of the white ink, and effectively prevent the aggregation or sedimentation of the components in the white ink, thereby contributing to the improvement of the uniform stability of the white ink. The addition of reactive diluents helps to optimize the overall formulation, enhancing the adhesion between the white ink and the substrate, and thus improving its durability.

As is clear from examples 1 and comparative examples 15 and 16, the addition amount of the dispersant was too small, the white ink was liable to be agglomerated, settled, and the like, and the viscosity was too high, so that it was difficult to secure the coating performance of the white ink. When the amount of the dispersant added is too large, the fluidity of the white ink is large, color uniformity and stability are difficult to maintain, and weather resistance is poor. As is clear from example 1 and comparative examples 17 and 18, when the amount of the leveling agent added is too small, the fluidity of the white ink is poor, the distribution is uneven, and the formation of a splice line is likely to occur, resulting in poor processing. When the leveling agent is used excessively, the appearance of the color retention ink is deteriorated, and the transmittance of the color retention ink is affected.

The foregoing is only illustrative of the preferred embodiments and principles of the present invention, and changes in specific embodiments will occur to those skilled in the art upon consideration of the teachings provided herein, and such changes are intended to be included within the scope of the invention as defined by the claims.

Claims

1. The white ink composition for the LED is characterized by comprising the following components in parts by weight:

5-40 parts of epoxy resin;

0.01-20 parts of curing agent;

21.05-70 parts of inorganic filler;

0.1-3 parts of dispersing agent;

0.2-4 parts of leveling agent;

2.94-91.5 parts of diluent;

2. The white ink composition for an LED of claim 1, wherein the inorganic filler is any one or a combination of a plurality of titanium white, barium sulfate, and modified fumed silica; the average grain diameter of the titanium dioxide is 25-2000 nm, and the addition amount of the titanium dioxide is 20-55 parts by weight; the average grain diameter of the barium sulfate is 400-3000 nm, and the adding amount of the barium sulfate is 1-10 parts by weight; the average grain diameter of the modified fumed silica is 5-120 nm, and the addition amount of the modified fumed silica is 0.05-5 parts by weight.

3. The white ink composition for an LED of claim 1, wherein the epoxy resin is a combination of any one of a silicone modified epoxy resin and a hybrid epoxy resin with a novolac epoxy resin;

4. A white ink composition for LED according to claim 1 or 3, wherein the epoxy resin has a viscosity of 300 to 200000cps at 25 ℃ and an epoxy value of 0.34 to 1.05.

5. A white ink composition for LED according to claim 1 or 3, wherein the curing agent comprises 0.01 to 3 parts by weight of an organic phosphorus derivative or 3 to 20 parts by weight of a microcapsule.

6. The white ink composition for LEDs of claim 1, wherein said dispersant is any one or more of polyether modified silicones, urea formaldehyde resins, phosphate modified acrylic acid, and the preferred dispersant is BYK-110.

7. The white ink composition for LEDs according to claim 1, wherein the leveling agent is any one or more of polyether modified silicones, urea-formaldehyde resins, phosphate modified acrylic acid, and the preferred leveling agent is basf leveling agent.

8. The white ink composition for LED according to claim 1, wherein the diluent comprises an inactive diluent, and the inactive diluent is added in an amount of 0 to 40 parts by weight, preferably any one or more of esters, ketones, amines, alcohols, and more preferably any one or two of propylene glycol methyl ether acetate and cyclohexanone.

9. The white ink composition for LEDs according to claim 1, wherein the diluent comprises a reactive diluent, and the reactive diluent is added in an amount of 2.94-51.5 parts by weight, preferably any one or more of 2-ethyl-hexyl glycidyl ether, styrene oxide, polyethylene glycol diglycidyl ether, diglycidyl aniline, and more preferably C ₁₂ ～C ₁₄ Alkyl glycidyl ethers.

10. The white ink composition for LED as claimed in claim 8 or 9, wherein the diluent is added in an amount of 10 to 40% by mass of the total mass of the white ink composition for LED.

11. The method for producing a white ink composition for LED according to any one of claims 1 to 10, comprising the steps of:

12. Use of the white ink composition for LEDs according to any one of claims 1 to 10 or the method for preparing the white ink composition for LEDs according to claim 11 in Mini LED backlight coatings, LED displays, printed electronics, LED lighting, piezo printing.