The gloss of the coating refers to the reflection ability of the surface of the coating to the light that is projected,the stronger the reflection ability,the greater the gloss.
Influence after the film gloss of barium sulfate powder material particle size and dispersion is the main cause of its performance,if the particle size of barium sulfate powder itself is very thin,and can be evenly dispersed to coating,the coating level off,the compact mirror,glossiness is very obvious;
On the other hand,barium sulphate has a coarse and uneven grain size,and the coating is rough and the gloss is reduced and the tone is dark.
Gloss is an important performance indicator of ink,which has a large effect on the appearance of the printed parts.
Traditional precipitate barium sulphate,not only dispersing,but also low gloss,can not be applied to the formulation system of ink.
Better material of barium sulfate in fact is added to the ink formula in the form of concentrated slurry,adding barium sulfate ingredients of the total amount for the slurry~20 wt%70 wt%,the average particle size of nano barium sulfate powder materials for 10 nm~1 microns.
In ink production,different types of ink products have different quality requirements for barium sulfate materials.
In addition,in the process of printing ink,it is also based on the specific characteristics of various kinds of ink and the requirement for the selection of barium sulphate with different properties.
1,the evaluation method of gloss
One way is to do the base barium sulphate compared with standard samples were made into film gloss analysis:barium sulfate sample by sand grinding evenly dispersed in alkyd resin,under controlled conditions in automatic spraying equipment,formed on the aluminium plate uniform film thickness and surface characteristics of wet film coating,and then baked to shape.
Finally use Hunterlab D-48-7 gloss reflectivity measuring 20°,calculate the glossiness ratio with standard sample.
Another system is mixed with Synocyl 9122 x resin made from 40%barium sulfate concentration aqueous acrylic coating volume,with 100 micron bar automatic coating membrane,into clean dry cabinet used after at least 5 h GlossgardⅡgloss measuring 20°glossiness.
Domestic usually will barium sulfate powder materials mixed with refined linseed oil on a flat grinding machine grinding made of plaster,and then use automatically wet film preparation of coating on the glass plate is measured.
It is not completely objective to evaluate the gloss of the coating,but the visual classification by different observers usually has reasonable correlation.
The status of the technology of improving the application of barium sulphate powders in foreign countries
High gloss barium sulfate powder materials are usually coated on the surface of a layer or multilayer metal oxides,such as silica,alumina and other ingredients,through the way of neutralization help or coprecipitation oxide doped wrapped in barium sulfate particles surface,addition amount of barium sulfate 0.5 wt%~3 wt%of the total.
Organic surface coating coated carboxylic acid,silane and siloxane,hydrocarbon wax with barium sulfate crystal particles and surface reaction product of addition amount of barium sulfate 0.5 wt%~1.5 wt%of the total.
Commercial products such as Gemme Micron,single aluminum envelope product b-35,silicon aluminium envelope b-30,b-34 and other types of barium sulphate products of organic silicon surface coating.
The basic b-30 has long occupied China's high-end ink market.
2.1 increases the technology of barium sulfate
Gemme Corp unveiled a high gloss,high weather resistance preparation methods of surface treatment barium sulfate,the product is coated on the surface of porous alumina and dense alumina,of the total mass of alumina concentration for BaSO4(2~6)%,the density of alumina and the quality of the thin diaspore alumina ratio of 8:1~1:2,dense alumina with sulfuric acid root ion mass ratio of 10:1~1.3:1.
Dense alumina is a kind of alumina containing sulfuric acid root ion,which is sulfuric acid root ion adsorption in the form of alumina,alumina and sulfuric acid root ion mass ratio of 10:1~1.3:1.
When(30~65℃),pH value of(5.2~6.5)under the condition of alumina and sulfuric acid root ion contact reaction for a period of time,so as to make the densification of alumina.
The thin water alumina is a crystalline form of alumina,containing adsorption water.
Water is inserted into the Al(OH)six octahedral layer in a random and regular manner.
BaSO4 crystal surface coated with dense alumina makes its durability such as light resistance and improved powder resistance.
On the surface of BaSO4 crystal,the aluminum oxide layer of alumina has improved its gloss and dispersion.
Gemme Corp is another kind of the preparation of barium sulfate has improve gloss,weatherability,surface treatment methods:barium sulfate with a variety of metal salt treatment,such as 1.0%~3.0%Al2O3 aluminium,zirconium,phosphorus compounds,at least one metal salt anions can offer a price.
According to the wet treatment,the average aluminum compound is 1.0%~3.0%Al2O3.
Based on the surface deposition,the addition of zirconium compounds was 0.1%~0.4%.
The amount of phosphorus compounds was 0.1%~0.5%.
The organic coating is 0.2 to 0.4 percent TMP,TME,or pentaerythritol.
Soluble metal salts have been found in the polyvalent anions such as SO42-ion exchange process to coated with attachment in barium sulfate crystal surface,the conventional water indivisible these polyvalent anions cause flocculation,reduce the dispersion and the final product whiteness,glossiness and weather resistance.
The metal salts,which contain an anion,effectively reduce the trend and potential.
Gemme Corp through strict control of barium sulfate slurry pH,temperature,silicon and aluminum in time preparation with surface treatment to improve gloss and weatherability of barium sulfate powder materials:under the condition of 75℃,pH=10.0,pH=9.4,pH=4.9 respectively to join silicon compounds,each step for at least 10~20 min;
PH=5.5~7.5,under the condition of 75℃to aluminum compounds.
The amount of silicon oxide is 2.5 to 3.5 percent of BaSO4 weight,and alumina is 1.6 to 1.9 percent of BaSO4 weight.
Finally,the organic package covered 0.2%to 0.8%of TMP.
Silicon,aluminum deposition time 10~45min,the whole continuous process including no more than 120min.
The surface treatment of barium sulphate has excellent gloss advantage and has excellent compatibility in paint,ink and coating.
The shading force and the hagumann data show that the barium sulphate,which is prepared by the method,is very dispersible and does not appear to be condensed when applied to paint and ink.
It increases barium sulfate and dispersive technology
Gemme Corp processed surface of barium sulfate deposition at least a one yuan amine salt processing,materials applied to the preparation of barium sulfate glossiness and dispersity obviously improved.
Amines can be dihydroxymethylpropionate,DMPA,DMPA+TIPA+TME,DMPA+TIPA+TMP,dihydroxymethyl butyric acid DMBA+TIPA,DMBA+TIPA+TME,DMPA+TIPA+TMP.
The DMPA or DMBA is 1-1:1 to the ratio of TIPA to the mole ratio of TIPA,and the resulting neutral salt is not an excess of alkanamine.
The ratio of amine salt to TME or TMP is 95:5-1:1.
The addition of amine salt to the quality of titanium dioxide is 0.2 wt%.
With untreated barium sulfate and simple by the TME compared treatment or other amine salt barium sulfate,the method could be prepared for the improvement of surface treatment barium sulfate on the dispersion and glossiness is significant,especially when used for water-based coating can significantly reduce the dosage of dispersants,it is also its greatest strength.
Other technologies to improve barium sulfate application
Gemme Corp USES aluminium oxide to wrap up the barium sulphate powder to improve the gloss and dispersibility of its oil systems.
In turn add alkaline aqueous aluminum compounds and acidic compounds,barium sulfate in the total of suspending liquid volume weight of 1 wt%~4 wt%,including the amount of alkaline elements of aluminum compounds in aqueous solution with acid aluminum compounds,the ratio of the amount of aluminum to join in the aqueous solution of 1:1 to 1:3.
The method can be used to handle the barium sulphate pulp made in any form,and the steps can be carried out intermittently.
source：未知
time :2017-06-12 23:28
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