Application of all-water ink in intaglio printing on plastic film

1.

Water-based ink is abbreviated as "water-based ink", which uses water as the solvent, replacing the organic solvent which accounts for about 30% to 70% in traditional solvent-based inks

Water-based acrylic inks are mostly used in relatively common printing, such as: supermarket shopping bags, sanitary consumables, industrial packaging bags and other surface printing coatings online coatingol.

Water-based polyurethane inks have a wide range of uses, especially in flexible food packaging.

At present, whether it is an acrylic system or a polyurethane system, the water-based ink can be integrated with OPP, PET, and NY, and the polyurethane system can also be boiled in water, high temperature, and high pressure at about 121~131 ℃ without any problem

Hybrid resin-based water-based inks are unique in their application in the field of laminating composites

2.

The production and application of all-water inks do not add toxic organic solvents, fundamentally eliminate the volatilization of harmful gases, and are truly green and environmentally friendly materials

At present, there are two ways to solve the pollution of VOCs in the printing industry: one is source treatment, and the other is end treatment

I think the root of all problems is that there is a problem with ink and wash cognition and thinking
.
If you want to completely solve the problem of VOCs emissions, you should first change your thinking, learn from the pain, and make up your mind
.

The method has the following two points:

First: re-understand what kind of ink is good ink
.
What kind of ink and wash is the true meaning of ink and wash
.
How to choose a good ink? This is the first step
.

The second is to change your thinking and re-understand the application methods of ink and wash.
Otherwise, even the best ink and wash will not work well
.

Third, the performance that a good water-based ink should have

A good water-based ink must have the following points:

1.
High color density, high solid content, stable viscosity;

2.
Bright colors, strong color development, stable L, a, and b values ​​to facilitate the color management of the color printing factory;

3.
The printing adaptability of ink should be strong, the fatigue resistance should be good, and there should be no problems such as cutting lines in long-term printing;

4.
Good leveling, adhesion, water resistance, quick-drying, and transferability;

5.
OPP, PET, NY integration, easy to use, easy to manage and apply;

6.
You can print with water, don't let the printing factory spend money on alcohol;

7.
The overall cost is lower than that of solvent ink, which is beneficial to the cost control of the printing plant;

8.
The printed matter should be able to meet the customer's requirements, especially the problem of light shifting in the light screen (the reflection of highlights and shadows)
.

Fourth, how to use ink well

First of all, you must accept ink and wash, make up your mind to change to ink and wash, and then choose ink and wash
.
Judging and choosing ink and wash is a technical task, and finally how to use ink well, that is, the application of ink and wash is very important
.

To make good use of ink and wash printing is a systematic project, not just ink and wash itself
.
The quality of the ink, the drying system of the printing press, the production of printing plates, the surface characteristics of different films, the operating methods of the employees, the adjustment of operating habits and the subsequent lamination requirements must be organically connected together in order to make good use of the ink and achieve the best Good condition
.
Otherwise, as long as there is a problem in one of the links, other problems will occur correspondingly, which is not good
.
This is why there is often a saying in the market that ink and wash are immature
.

1.
Choose good ink products

Choosing a good ink is to judge the quality of ink
.
This is a problem that the ink factory must solve, and it is also the most basic requirement
.

A good water-based ink must be integrated, that is, it can be printed on different plastic films.
OPP, PET, NY can all meet the printing requirements.
This will help the management of the printing plant to avoid different films to prepare different inks.
This is much more complicated and the cost waste is also great
.
Fujian Green Spring has successfully made breakthroughs in this area of ​​technology, and can even perform high-temperature and high-pressure cooking
.

2.
Drying of ink

Next, we must consider the problem of ink drying.
At present, more than 95% of the printing equipment on the market is not configured for ink
.
The volatilization conditions of water are more demanding than the volatilization conditions of solvents
.
As long as the solvent has a certain temperature and air volume, it evaporates quickly, and the saturated vapor pressure of water is too different from the saturated vapor pressure of the solvent
.
Water can only volatilize quickly under certain conditions of temperature, pressure, wind speed, and air volume
.
But the drying system of the existing printing presses can hardly meet the requirements
.
The only way is to transform the drying system and spend a small amount of money to do big things.
It is more than enough to spend one-tenth of the investment of buying RTO and RCO to transform the drying system of the printing press
.

Solving the dryness problem of ink printing has nothing to do with the brand of the printing machine, but is often directly related to the drying ability of the printing machine itself
.
Generally, the drying system of a printing press meets the following conditions, and the speed of ink printing should be no problem:

1.
The temperature of the oven: OPP film, NY film printing temperature 60~65℃, PET film 65~75℃;

2.
The pressure of the oven: the pressure of each part of the air box reaches 1.
5~2kPa evenly;

3.
Air volume of the oven: 4000~4500m3/h;

4.
The wind speed of the oven: the direction of the tuyere and the wind speed of 30~40m/s;

5.
Negative pressure of the oven: There must be a certain slight negative pressure to discharge the water vapor in the oven;

6.
The length of the oven: generally above 1.
5m;

7.
The air outlet of the oven should be designed as reasonably as possible
.

To meet the above conditions, the dryness problem of ink printing should be solved
.

At the same time, we also need to consider the thorough dryness of ink printing, that is, whether the ink still contains a certain amount of moisture after printing and rewinding.
This is very important
.
Because this will affect the subsequent process of composite bag making at any time, generally speaking, even if the drying system of the printing equipment is good in the process of high-speed printing, 100% drying cannot be guaranteed
.
That will affect the subsequent solvent-free compounding.
Therefore, it is recommended to install a cold air drying system on the printing machine to help the moisture completely dry and an online moisture content detection system before rewinding, so as to better understand whether the printed product is Contains water, if so, how much to make a correct judgment
.