Ink Manufacturing Three Roll Mill

Ink manufacturing process can be described as a mixing process. Pigments, binder and additives are usually separately synthesized beforehand. An important task in this process is pigment dispersion. To break up pigment agglomerates, three roll mill, ball mill, and other type of mills might be employed. Three roll mill provides the highest shear force. It's commonly used in the production of screen-printing inks, pad printing inks, UV inks, glass inks, and other variety of inks.

Three roll mill is especially effective for pigment dispersion in high viscosity paste for heavy offset-litho base inks. It will be difficult to mill a liquid ink on a three roll mill, since the solvent tends to evaporate. Ball mills, instead, have been used to mill liquid inks. However, good dispersion through ball milling could only be obtained at proper viscosity (between 1600 to 2400 cps).

Pigment Dispersion

The primary purpose of the dispersion process is to break down pigment aggregates and agglomerates to their optimum pigment particulate size and distributes these pigment particles evenly throughout the similar medium i.e. the carrier.

Once the varnish (containing the solvent, resin and additives) has been produced the pigment is mixed into it. At this point the pigment particles clump together. These clumps must be broken up and the pigment dispersed evenly through the resin by three roll mills.

Carbon Black Dispersion

Carbon properties influence ink performance. For example, the smaller particle size increases blackness, tint, UV protection and absorption, electrical conductivity. The higher structure could reduce blackness and tint, improve dispersibility, increases vehicle demand and viscosity, and increases electrical conductivity. The higher porosity could increases vehicle demand and viscosity and electrical conductivity and reduce loadings in conductive applications. High surface activity will improve vehicle wetting, reduce viscosity of liquid system and lower electrical conductivity.

Carbon black dispersion include the follow steps: incorporating the carbon black in the vehicle system, dispersion the air entrained in the carbon black with the vehicle (wetting the pigment), and reducing carbon black agglomerates or aggregates through grinding. Good interaction between the vehicle and carbon black will facilitate wetting and accelerate the dispersion process. In other words, better carbon black/resin interaction means better ink stability. The proper choice of effective wetting and dispersing agents can provide vast improvements in ink performance. In the ink industry, the dispersion is usually characterized by Hegman gages.

And as mentioned before, the type of equipment used to disperse carbon black depends on the viscosity of the ink. Ink makers generally use three roll mills to handle high viscosity paste ink formulas at relatively low temperatures.

UV Ink Manufacture

UV curing inks have become one of the fastest growing segments in the graphic industry. UV inks are employed in offset printing and flexo printing as well as in screen printing.

Major benefits offered by UV technology are faster run speeds resulting in improved productivity, quick start-up resulting in less waste, quick turnaround and converting due to instant curing of the ink film, environmentally safe technology without the use of VOCs, and higher print quality (i.e. gloss).

Three roll mills were used for UV inks because bead mills created an uncontrolled thermal reaction which could lead to polymerization.

The composition consists of oligomer, fluorescent dye and photopolymerizable vehicle. Generally, a fluorescent ink concentrate is synthesized first. One example is to combine 38g water with 0.45 g potassium tetraborate, 40.44 g of formaldlehyde, and 104.9 g of toluenesulfonamide. The reaction was heated to 100 C. During the heating process, 26.8 g of Solvent Yellow 85, 3.98 g of Basic Red 1, and 0.7 g of Basci Violet 11 was added and 26.76 g of melamine was added to 85 C. The reaction was held at 100 C, for 5 minutes upon which a solution of 250 g of trimethylolpropane triacrylalte with 0.4 g of hydroquinone was added to the reaction. The mix was heated to 110 C and milled on three roll mill at room temperature, to provide fluorescent orange ink concentrate. The above 7.0 g concentrate was combined with 1.0 g of Ebecryl 3608, a fatty acid modified epoxy acrylate, and 0.3 g of trimethylolpropane triacrylate, to provide a fluorescent ink.

Specifications

Parameter T65 Ink Mill T65B Ink Mill
Diameter of Roller 2.5” (65mm) 2.5" (65mm)
Length of Roller 5.0” (127mm) 10" (254mm)
Roller Speed Ratio (Fixed) 1:2:4 1:2:4
Speed of Roller
RPM
Slow Roller 0~108 0~108
Mid Roller 0~216 0~216
Fast Roller 0~432 0~432
Motor Power 3/4HP / .55kW 3/4HP / .55kW
Weight 165 lbs (75kg) 175 lbs (80kg)
Dimensions 25”x11”x15”
(635mmx280mm
x381mm)
30"x11"x15" (770mmx280mm
x381mm)
Throughput Up to 20 L/h Up to 45 L/h
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Safety Features

  • Large mushroom style red emergency stop button
  • Emergency pull cord
  • VFD enabled wash-up operation mode
  • Nip guard