Definition
Ink stirring disperser is a type of laboratory equipment used to efficiently mix and disperse pigments, resins, solvents, and other components in inks. Its core function is to break the pigment aggregates through mechanical action to achieve uniform distribution of particles in the liquid phase, so as to obtain stable and consistent ink samples, providing a basis for subsequent R&D, quality inspection and process adjustment.
Principle
The working principle of this equipment is mainly based on high-speed shearing and cyclic mixing. The motor drives the stirring shaft and drives the dispersion disc or blade at the end to rotate at high speed. The rotation creates a strong shear force that acts directly on the material. At the same time, the equipment design often promotes the formation of an axial and radial circulation of materials, ensuring that components in each area of the container are fully involved in the shear area. The entire process is designed to separate the pigment aggregates into primary particles, which are wetted and encased in a liquid medium to form a stable dispersion system. The shear rate and dispersion effect can be related to the following relationships:τ = μ * γ, where τ represents shear stress, μ is the viscosity of the material, and γ is the shear rate. Higher shear rates help generate greater shear stress, resulting in more efficient dispersion.
Measurement and evaluation methods
The evaluation of the treatment effect of the ink stirrer disperser is usually not directly measured by the equipment itself, but indirectly evaluated by the performance test of the produced ink sample. Common methods include fineness determination, which uses a scraper fineness meter to assess the maximum particle size or degree of agglomeration of pigment particles; Viscosity test, using a rotational viscometer to monitor the changes in rheological properties before and after dispersion and during storage; and color intensity and hue evaluation, comparing the color difference between the standard sample and the test sample by a spectrophotometer. In addition, observing the sedimentation stability of dispersions is also an important means to evaluate the long-term effects of dispersion.
Influencing factors
The dispersion effect is affected by multiple factors. In terms of equipment parameters, the shape, diameter and linear velocity of the dispersion disc directly determine the shear strength. The insertion depth and angle of the stirring shaft affect the flow field circulation mode. Process parameters include dispersion time, temperature control, and batch dosing strategies. The material characteristics involve the properties and concentration of pigments in the ink formulation, the viscosity of the resin solution, and the polarity of the solvent. These factors need to be synergistic optimization according to the specific ink system.
Applications
Ink stirring and dispersing machines are widely used in situations where liquid ink needs to be prepared or studied. In the printing ink R&D laboratory, it is used for the exploration of new formulations and sample preparation. In the manufacturing of packaging materials, textile printing, and electronics such as conductive inks, it is used for pre-production process validation and small-batch prototyping. In the quality inspection department, it is used for incoming material inspection or quality control in the production process to ensure that the dispersion quality of inks meets internal specifications or industry standards.
Selection considerations
Choosing the right ink mixer and disperser requires comprehensive consideration. First, it is necessary to clarify the characteristics of the material being processed, such as the expected throughput, viscosity range, and corrosiveness, to determine the capacity of the equipment, the power of the motor, and the material of the contact parts. Secondly, according to the requirements of dispersion accuracy for experimental purposes, the speed range and control accuracy provided by the equipment are examined. Safety features such as overload protection and emergency braking are necessary considerations. Finally, the ease of use, ease of cleaning and maintenance, and whether it has data logging functions also have an impact on the efficiency of long-term use. It is recommended to refer to the principled requirements for sample preparation equipment in relevant industry standards (such as standards related to physical test methods for coatings and inks) and make decisions based on actual process needs.