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Print knowledge--determination of the rheological properties of screen printing ink

    determination of ink properties

    screen printing ink components mainly for the pigment particles, resins, solvents, modifying agents. main role although only display colors of pigment particles, particle size and dispersion has some effect on the rheology of ink. modifier's primary role is to improve some rheological properties of ink.

    principles and process of screen printing

    using Shi, silk printing ink through extrusion through a layer rushed Sun has graphics (hole) of nylon, ink through cloth Shang of small hole printing to objects Shang, formed image. each square inches hole of number decided has printing of quality, while also effect ink of rheological performance. in printing Qian in the, ink tile in screen Shang, cannot through network hole drops Xia. such on requirements ink in low shear force role Xia has high of stick degrees, and in gravity role Xia not flow. using Shi, Wheel pressure had network cloth Shi, ink by extrusion and through network hole. such, ink must in forces Xia shear variable dilute, in revoked forces Xia, can fast recovery original structure, and high stick degrees, not placed ink will through mesh drops Xia. Dang wheel this after network cloth, and put network cloth into pressure in print Shang Shi, ink on will according to network cloth Shang of hole of distribution to dot of form distribution to objects Shang. then, ink structure recovery of time length is key, had short, will led to shortcomings, had long, The resulting scatter. both situations will lead to reduction of image sharpness.

    rheological analysis

    the below mentioned laboratory instrument used to fly Brookfield Boli R/S rheometer. temperature of 25 degrees Celsius.

    relationship between stress and viscosity:

    from Figure 2 of rheological curve displayed has two species different products of stress/stick degrees of rheological figure. in test in the, first on samples, to must of direction imposed forces a time, records Xia shear rate size, that late, stick degrees = shear stress/shear stress. then increased stress size, repeat above steps. Dang stress increased to 5Pa Shi, samples a, of stick degrees almost than samples b high out four a number level, and in high shear Xia variable dilute. from Shang figure can see, Ink in the b will release ink. under high shear viscosity will be a great change. using conventional measurement methods, cannot measure the inks of different structures.

    measuring instrument introduction

    1. Bo force fly R/S rheological instrument Brookfield Bo force fly R/S rheological instrument as performance most excellent of rheological instrument, in with type products performance price than best. it has two species control mode: directly control shear stress mode, and control shear rate mode. for directly control shear stress mode, can directly measurement out samples of yield stress, and stick degrees with stress changes of rheological characteristics. Control shear rate mode, Its usage and the viscometer Brookfield DV series can completely replace the DV series of viscometers.

    2. Brookfield viscometer DV series:

    in this experiment, you can use DV-2+, instead of R/S or DV-3+ viscometer/rheometer rheometer. use suitable accessories and software can also simulate the yield stress, and stress change of viscosity of rheological properties.

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