First, the concept and application of nanometer
The word "nano" has attracted a lot of attention, but one important point is that we should not stick to the size of nanometers. We only emphasize that nanotechnology is below 100nm. What matters is that the fineness of size can bring us benefits, such as The improvement of pigment properties by nano-particles is an expected benefit.
There are a lot of nano-products, and throughout the industry, from 2001, the global nano-industry has about 26.5 billion US dollars, its application in the product area is mostly a powder structure, in the application will be limited due to aggregation, so how to break through this Applying technology to disperse the powder to the fineness we need will be the focus of this stage. Looking at the scope of nanospecialized products, the proportion of ink coatings in the overall output value is quite large, and each product is also related to each other. Therefore, nano-ink coating will be a very important part of nanospecific products. field. The UnitProcess of nanospecialized products mainly deals with powders. The processes such as grinding, manufacturing, and processing into finished products can all show the characteristics of the products, and examples include inkjet inks, paint plastics, and pharmaceutical products.
Second, nano-dispersion technology
There are two main problems in nano-dispersion technology. The first is to disaggregate and deagglomerate large particles to enhance their original characteristics. The second is to re-disperse small nano-sized powders in order to achieve mass production, low cost, and small amounts of additives. effective. In the nano-dispersion of pigments, the dispersion of powder is the most difficult point, and there are also technical bottlenecks that must be overcome. It is not easy for a traditional ball-milled bead mill to reach 200 nm. To achieve smaller particles, it is necessary to rely on grinding and dispersing technology. The particles of the grinding ball must be fine and the energy transfer must be sufficient to increase the collision frequency and obtain smaller particles. The smaller the particles, the stronger the aggregation effect. Therefore, we must use the interface point of view to stabilize the particles. Stabilizers, dubbed products such as inks, coatings, etc.
Traditional bead mills use beads to collide at high speeds, but the separation nets block the beads inside, and the technology of separating the nets is still insurmountable. Since the smallest beads are currently about 0.05 mm, the grinding balls are not small enough to separate the particles. It is very small, so it limits the development of technology, and because its equipment is expensive, it is not easy to maintain, and it cannot meet even more subtle needs, so new equipment must be developed. And decentralized equipment must pay attention to:
1. The internal design of the grinding tank.
2. The grinding tank drives the shaft material.
3. Kind of grinding media.
4. Dispersion and grinding media separation mechanism and pore size.
5. Operation method.
The nano-beads grinding and dispersing system adopts materials with wear-resisting and high-heat-transmission effects to manufacture tanks, low-cost grinding media, and high energy density stirring shafts, blades, and tank bodies. The principle is to use a single agitating tank to place fine grinding balls and transfer it into the agitator with a high blade speed of mechanical force >15~30m/s. The dispersion effect created by microbead mill has two main points:
(1) The increase of the collision point: the collision point is closely related to the diameter, and the smaller the diameter of the grinding media, the collision point will also increase. Take the 0.05mm grinding media as an example, the collision point is far more than 0.5mm grinding media. Times.
(b) Increased effective shear surface: The smaller the beads, the greater the number, and the shear force will increase.
However, it must be noted that although small grinding media have a good effect on microbead grinding, they cannot be dispersed if the grinding media and the volume of the powder are not far apart. In general, the size of the powder is 1/3-1/10 of the grinding media, and the hardness, ph value, color deviation, cost, and contamination of the grinding media are also required. What is also worth noting is the interface stabilization technology of nanopowders. When the particles become smaller, the distance between the particles also decreases, and the stability decreases accordingly. Therefore, the amount of dispersant must also be increased.
The criteria for the selection of dispersants should be from the application point of view. For example, for the application of ink-jet inks, the HLB value should be similar to the HLB value of the pigment demand in terms of the need for grinding and dispersion; and good wetting and dispersing properties and low foaming properties should be considered. In terms of ink function requirements, storage and stability of additives, stability of ink transport in ink cartridges, and anti-blocking properties should be considered. Ink spraying on paper requires good water resistance and rub resistance and has anti-solvent properties. And heat resistance and so on.
Third, pigment coating ink nano-application
In practical verification of pigment nanocrystallization, the color appearance of nanometer pigments is far darker than that of submicron pigments. The main reason is that the particles of the pigment are large, and the light will break through and the light will be scattered out of the light. The light penetrates through. The nanopigment has a small particle size, weak light scattering, a small spectral absorption area, and a light reflectance of less than 1%, so the appearance of the color is significantly deeper than the submicron pigment.
Nano-pigmented pigments have a wide range of applications, such as ink-jet inks, coatings, inks, and optoelectronic displays. In the manufacturing process of products, the addition of nano pigments with a small proportion of 3%-5% can improve inks. Shading rate, saturation, anti-rotation, water resistance and other issues.