lithopone manufacturing process

Polyvinyl Butyral Resin (PVB) is a solvent Resin synthesized by the acetal reaction of Polyvinyl Alcohol (PVA) and butyraldehyde in contact with coal.

Because Pvb Resin itself contains a lot of hydroxyl groups, it can bridge with some thermosetting resins to improve the properties of chemicals and film hardness.

Because PVB resin has the above excellent characteristics, it is widely used in adhesive safety glass intermediate film of automobile and building, rust cutting primer, baking paint, wood paint, printing ink, adhesive of electronic ceramics and printed circuit board, adhesive between metal and metal, between metal and plastic, modifier of hot-melt adhesive, iron dimension waterproof processing of textile, etc. A variety of new industrial applications are also continuously developed and applied.

The general characteristics of PVB are as follows:

The appearance of polyvinyl butyral (PVB) resin is white spherical porous particles or powder, and its specific gravity is 1:1; However, the filling density is only 0.20 ~ 0.35g/ml.

Thermal properties

The glass transfer temperature (TG) of polyvinyl butyral (PVB) resin ranges from 50 ℃ of low degree of recombination to 90 ℃ of high degree of recombination; The glass transfer temperature can also be adjusted by adding an appropriate amount of Plasticizer to reduce it below 10 ℃.

Mechanical properties

The coating of polyvinyl butyral (PVB) resin has good water resistance, water resistance and oil resistance (it is resistant to aliphatic, mineral, animal and vegetable oils, but not to sesame oil). PVB is widely used in printing inks and coatings because it contains high hydroxyl groups and has good dispersibility to pigments.

In addition, its chemical structure contains both hydrophobic acetal and acetic ACID groups and hydrophilic hydroxyl groups, so PVB has good adhesion to glass, metal, plastic, leather and wood.

Chemical reaction

Any chemical that can react with secondary alcohol will also react with PVB. Therefore, in many applications of PVB, it is often used with thermosetting resin to bridge and harden with the hydroxyl group of PVB, so as to achieve the characteristics of chemical resistance, solvent resistance and water resistance.

Of course, films with different characteristics (such as hardness, toughness, impact resistance, etc.) can be prepared according to different types of thermosetting resin and different mixing ratio with PVB.

Safety properties

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In a preferred technical solution, 3⁄40 2 is added to the Lide powder emulsion of the metathesis reaction step, and the mass fraction of 3⁄40 2 added is 10 to 33%, and the lithopone emulsion is desulfurized (mainly hydrosulfate ion or Elemental sulfur), slowly added 3⁄40 2 until the lithopone emulsion is colorless and transparent. The obtained sulfate ion can be recycled and reused in the production process. The chemical reaction equation is: 43⁄40 2 + HS— + OH— → SO/— + 5H 2 0

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The composition of lithopone underscores its superiority in specific applications. Ideally, prepared lithopone consists of 30 to 32 percent sulfide of zinc, and a negligible percentage of zinc oxide (1.5%), with the remaining majority being barium sulfate. These attributes render lithopone nearly comparable to the best grades of French process zinc oxide in terms of whiteness. Furthermore, its oil absorption, which sits between lead carbonate and zinc oxide, solidifies its position as a functional and efficient white pigment.

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TiO2 is also known for its high refractive index, which means that it has the ability to bend and reflect light effectively. This property makes TiO2 an ideal pigment for enhancing the color and print quality of paper products. By using TiO2 in the paper manufacturing process, paper suppliers can achieve vibrant colors and sharp images that stand out on the page. This is particularly important for printed materials such as magazines, brochures, and packaging, where visual appeal is a key factor in attracting consumers.

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