2.2 Sinks:
A, failure phenomenon:
When the ink is packaged and printed on the vertical surface and the varnish coating and finishing production process flow, the ink or the coating oil tends to flow down due to gravity during the film formation (A. When the ink or oil contacts the substrate and spreads out B. When a certain amount of gravitational force is reached at the last minute; C. Contact with the substrate is gradually spread.) This flow is maintained after the film is formed, resulting in uneven surface flow (spreading), uneven thickness of the upper and lower film, and thickening of the bottom edge. From the above three conditions A, B, and C, we hope to see that the status of C is encouraging. Because from the observed fluidity, the spreading task was completed within the prescribed time, but A often produces water marks, and B often produces cracks. This is based on the above-mentioned shape of the flow mark is divided into the following types: (1) sag: ink and coating oil can not go up (front) flow and gradually thickening, or stranded on the bottom edge, dry curing Afterwards, they are often retained as they are; (2) Rogue: When ink or varnish is mechanically printed on the surface of the substrate, it hangs on a large area and is often called a watermark. (3) Dropping: This is the state of B in this article. Local sagging occurs during printing, painting, or temperature-increasing drying, forming wave-shaped (called watermarks), semi-circular (stripes) or stripe-like secondary waste products.
B. Reasons:
In essence, ink or varnish sag is associated with the fluidity or rheological characteristics of the ink or varnish during printing and coating. Sometimes it is related to the processing quality of the substrate. For example, when the pressure of printing or coating is still on a smooth surface with poor adhesion, the sag situation may easily occur.
When we adjusted the rheological properties of packaging printing inks or coating oils, it greatly promoted the low viscosity of inks or coating oils at high shearing speeds, which in turn facilitates the inks or coating oils. Leveling. At the same time, when we have a high viscosity at a low shear rate (ink or varnish film), it prevents sagging, which is a very difficult task. Most manufacturers use appropriate low-viscosity, high-content resin binders. Choosing a pigment, filler, and adjuvant with a moderate pH, the inks or varnish made to make it thixotropy for general printing. It pursues the unifying purpose of preventing conflicts between sag and leveling.
The viscosity of packaging printing inks and coating oils has a great relationship with the solvent volatilization rate and volatilization gradient in the printing and coating processes. The volatilization of the solvent is fast and the viscosity of the ink is fast, which helps to prevent sagging, but it is not easy to level out. The drying and curing speed of thermosetting or light-curing packaging printing inks or coating oils is directly related to viscosity changes. Slow response, low viscosity, and easy sagging are tasks that we should take seriously.
We know that the temperature and light intensity have a great influence on the viscosity. In the packaging printing ink or varnish system with volatilization and drying properties, oxidative permeation and drying properties, photocurable properties and thermosetting properties, the viscosity of the wet film of the amino ink is high-temperature baking. Falling, often causing sag is one of the headaches. This problem is usually solved with a "wet-to-wet" print production.
This is what we often say that Newtonian fluids flow under gravity in the vertical plane. If the viscosity of the ink film or the oil film is not considered, the speed of the outflow (spreading) of the packaged printing ink or coating oil and the spreading condition of the ink or ink that has flowed out. This is related to the density of ink or varnish, gravitational acceleration: the viscosity of the ink and the varnish film = the thickness of the film.
In fact, the viscosity of packaging printing inks or coating oils is a non-Newtonian type of fluid in the proton acceptor (acid) and electron donor (base) phase equilibrium processes/film formation and drying processes. We can see from the above two forms that it is not suitable for applying inks or coating oils. However, it can be seen that it is proportional to the square of the film thickness n and the third power of Q and n. Therefore, in order to prevent sagging, it is crucial to strictly control the thickness of the ink film or film.
On the other hand, the yield value of the ink or coating can be increased to increase the sag limit, which is a direct relationship between them. There are also new technologies such as “wet touch wet†printing or ultra-high-speed cup type electrostatic printers to achieve their goals.
C. Countermeasures:
Sagging and leveling is one of the most common failures encountered in the development of ink package printing and gloss coating development. The development of inks can meet the requirements of ink printing operations. Varying lustre ink or varnish is required for gloss coating to prevent sagging. . It is an effective way to choose the appropriate components of anti-sagging additives and leveling agents for different inks and varnish. If the two are harmonized together, additives are the direction of development. If the ink is added to TM-200S produced by Tianyang Chemical Plant, solvent-based ink can increase the viscosity and improve gloss by adding TM-27 coupling agent. Gel and gelled ink can flow immediately when added to TM-3. It is not possible to prevent stack printing.
Second, the correct choice of solvents and thinners, to control the viscosity of the ink or coating and changes in the viscosity of the drying process. Thirdly, it is also possible to use the above-mentioned method for a bright thermosetting ink or varnish, a photocurable UV ink or a varnish. Ink film, film reprint, recoating or pre-polished. Its four packaging printing or coating finishing, strict ink film, oil film thickness management, glazing when the operator's skills assessment, the quality of printing materials on the various substrates of the quality control, and air pressure, printing speed, Drying time, blowing angle, overprinting distance should be mastered. Fifth, strictly control the environmental management in the printing and finishing process, including the control of time, temperature, humidity, ventilation, and ventilation.
A, failure phenomenon:
When the ink is packaged and printed on the vertical surface and the varnish coating and finishing production process flow, the ink or the coating oil tends to flow down due to gravity during the film formation (A. When the ink or oil contacts the substrate and spreads out B. When a certain amount of gravitational force is reached at the last minute; C. Contact with the substrate is gradually spread.) This flow is maintained after the film is formed, resulting in uneven surface flow (spreading), uneven thickness of the upper and lower film, and thickening of the bottom edge. From the above three conditions A, B, and C, we hope to see that the status of C is encouraging. Because from the observed fluidity, the spreading task was completed within the prescribed time, but A often produces water marks, and B often produces cracks. This is based on the above-mentioned shape of the flow mark is divided into the following types: (1) sag: ink and coating oil can not go up (front) flow and gradually thickening, or stranded on the bottom edge, dry curing Afterwards, they are often retained as they are; (2) Rogue: When ink or varnish is mechanically printed on the surface of the substrate, it hangs on a large area and is often called a watermark. (3) Dropping: This is the state of B in this article. Local sagging occurs during printing, painting, or temperature-increasing drying, forming wave-shaped (called watermarks), semi-circular (stripes) or stripe-like secondary waste products.
B. Reasons:
In essence, ink or varnish sag is associated with the fluidity or rheological characteristics of the ink or varnish during printing and coating. Sometimes it is related to the processing quality of the substrate. For example, when the pressure of printing or coating is still on a smooth surface with poor adhesion, the sag situation may easily occur.
When we adjusted the rheological properties of packaging printing inks or coating oils, it greatly promoted the low viscosity of inks or coating oils at high shearing speeds, which in turn facilitates the inks or coating oils. Leveling. At the same time, when we have a high viscosity at a low shear rate (ink or varnish film), it prevents sagging, which is a very difficult task. Most manufacturers use appropriate low-viscosity, high-content resin binders. Choosing a pigment, filler, and adjuvant with a moderate pH, the inks or varnish made to make it thixotropy for general printing. It pursues the unifying purpose of preventing conflicts between sag and leveling.
The viscosity of packaging printing inks and coating oils has a great relationship with the solvent volatilization rate and volatilization gradient in the printing and coating processes. The volatilization of the solvent is fast and the viscosity of the ink is fast, which helps to prevent sagging, but it is not easy to level out. The drying and curing speed of thermosetting or light-curing packaging printing inks or coating oils is directly related to viscosity changes. Slow response, low viscosity, and easy sagging are tasks that we should take seriously.
We know that the temperature and light intensity have a great influence on the viscosity. In the packaging printing ink or varnish system with volatilization and drying properties, oxidative permeation and drying properties, photocurable properties and thermosetting properties, the viscosity of the wet film of the amino ink is high-temperature baking. Falling, often causing sag is one of the headaches. This problem is usually solved with a "wet-to-wet" print production.
This is what we often say that Newtonian fluids flow under gravity in the vertical plane. If the viscosity of the ink film or the oil film is not considered, the speed of the outflow (spreading) of the packaged printing ink or coating oil and the spreading condition of the ink or ink that has flowed out. This is related to the density of ink or varnish, gravitational acceleration: the viscosity of the ink and the varnish film = the thickness of the film.
In fact, the viscosity of packaging printing inks or coating oils is a non-Newtonian type of fluid in the proton acceptor (acid) and electron donor (base) phase equilibrium processes/film formation and drying processes. We can see from the above two forms that it is not suitable for applying inks or coating oils. However, it can be seen that it is proportional to the square of the film thickness n and the third power of Q and n. Therefore, in order to prevent sagging, it is crucial to strictly control the thickness of the ink film or film.
On the other hand, the yield value of the ink or coating can be increased to increase the sag limit, which is a direct relationship between them. There are also new technologies such as “wet touch wet†printing or ultra-high-speed cup type electrostatic printers to achieve their goals.
C. Countermeasures:
Sagging and leveling is one of the most common failures encountered in the development of ink package printing and gloss coating development. The development of inks can meet the requirements of ink printing operations. Varying lustre ink or varnish is required for gloss coating to prevent sagging. . It is an effective way to choose the appropriate components of anti-sagging additives and leveling agents for different inks and varnish. If the two are harmonized together, additives are the direction of development. If the ink is added to TM-200S produced by Tianyang Chemical Plant, solvent-based ink can increase the viscosity and improve gloss by adding TM-27 coupling agent. Gel and gelled ink can flow immediately when added to TM-3. It is not possible to prevent stack printing.
Second, the correct choice of solvents and thinners, to control the viscosity of the ink or coating and changes in the viscosity of the drying process. Thirdly, it is also possible to use the above-mentioned method for a bright thermosetting ink or varnish, a photocurable UV ink or a varnish. Ink film, film reprint, recoating or pre-polished. Its four packaging printing or coating finishing, strict ink film, oil film thickness management, glazing when the operator's skills assessment, the quality of printing materials on the various substrates of the quality control, and air pressure, printing speed, Drying time, blowing angle, overprinting distance should be mastered. Fifth, strictly control the environmental management in the printing and finishing process, including the control of time, temperature, humidity, ventilation, and ventilation.
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