With the development of printing,the application of pearl pigment in printing line is becoming more widely.From cosmetics, cigarette case,wines ,gift packing,business card to greeting cards and so on begin to use pearl pigment.Pearl pigment can provide a special pearl luster which are different from metal pigment and are accepted by many customers,so the application in printing are becoming popular.

Printing ink is made up of pigment,carrier and additive,the pigment can be powder,or slurry shape.The carrier is made up of resin and solvent,it is slurry shape or fluid substance which can make the operation convenient in printing.

Pearl pigment has excellent dispersibility.Generally it only needs light mill and can mix into printing ink with low viscosity.When we mix the printing ink with high viscosity,we don’t have to mill in a violent manner.Because the grain of pearl pigment is platelet shape,choosing appropriate particle size pearl pigment can make a key role in the transferring of ink and getting best pearl luster effect.

According to distribution’s equality on the printing,we can judge the ink effect.Only pigment wafer are parallel with printing,we can get ideal pearl luster. If the wet between pigment and solvent is not equal,it can make the pearl pigment scatter into the ink asymmetry and reduce pearl luster effect.Choosing appropriate printing can avoid bad influence to  printing effect,glossy and smooth surface can get better printing effect.In addition,the relationship of printing,net lines and pigment particle size,the best viscosity of ink,printing speed,dry condition,avoid pigment flocculation,the distribution of ink are very important.The speciality that pearl pigment needs depends on the mixing condition in ink.

The general printing methods are letterpress,offset, intaglio printing,soft printing, silk screen printing and surface printing.There are differences for pearl pigment in different printing methods.Generally speaking,the major factor that influent printing pearl luster effect are:printing method,the character of ink,transfer of ink,assort of colors and kinds of printing ,etc.

Printing process and recommendation of pearl pigment

A. letterpress

letterpress may be the first printing method that human beings adopt. Letterpress ink is slurry shape,and the viscosity ratio is between 50 and 300 poise,and the average particle size of pearl pigment is below 10-20um,because it will bring problems in printing process when it exceeds this size.The obvious is not good printing effect because of lack of viscosity and bad distribution.The following pearl pigment is our recommendation in letterpress:120,123,111,110 and so on.

B. flexographic printing

flexographic printing also call chry printing.Similar to letterpress,the viscosity ratio of flexographic printing ink is between 50 and 300 poise.It requires smaller grain of pearl pigment which is below 10u-20u.The pearl pigment suitable for letterpress are also suitable for flexographic printing.

C.intaglio printing(except for blink and highlight)

The viscosity ratio of pearl pigment in intaglio printing is very low,it is between 20 and 60 centi poise;There is no limitation to solvent type.Except for blink and highlight type,all the pearl pigment are sutiable for flexographic printing.

The depth of net roll determines the particle size of pearl pigment to a large certain extent.However,the following pigment are suitable for the net line whose depth is between 35-55um,and the net line is 70-120.Different net roll requires different pearl pigment,as following:

D.Soft and surface printing

Similar to intaglio printing,, Soft and surface printing also use ink with low viscosity ratio.So all the pearl pigment are suitable for these two printing except for blink and highlight types.

E.silk screen printing

The mesh of silk screen determines the average particle size of pigment.For example,200 mesh of silk screen (74um)except for blink and highlight can assort with the above pigments stated.But blink and highlight pigment requires bigger silk screen mesh(such as 80 mesh or 177um).All the pearl pigment are suitable for silk screen printing.We should pay attention that pearl pigment with big grain requires coarser silk screen.

F.dispersing of pearl pigment

When we confect pearl ink,we should add the peal pigment in the last period.It also means that when others parts have mixed equally,we can add.In this way it can avoid destroy because of exceed shearing.

When we produce,we should wet the pearl pigment fully with a small amount of solvent,then add a small amount of carrier ink and mix equally.Finally put dispersing ink into transparent ink left to make further mixing and dispersion.According to low shearing power and high speed to mix.It needs about 15minutes to make disperse equally.To avoid pigment being destroyed,the mixing machine with high shearing power are not allowed to be used,such as ball mill,stone mill and three roll machine,etc.