Titanium dioxide, a versatile and widely used material, finds its application in various industries including the rubber industry. This white pigment is known for its excellent UV resistance, durability, and opacity, making it an ideal choice for enhancing the properties of rubber products.
Lithopone was discovered in the 1870s by DuPont. It was manufactured by Krebs Pigments and Chemical Company and other companies.[2] The material came in different seals, which varied in the content of zinc sulfide. Gold seal and Bronze seals contain 40-50% zinc sulfide, offering more hiding power and strength.[3] Although its popularity peaked around 1920, approximately 223,352 tons were produced in 1990. It is mainly used in paints, putty, and in plastics.[1]
Skittles has been making headlines in recent weeks and not because a new flavor has been added to the popular taste the rainbow candy.
Titanium dioxide (TiO2) is a fine white powder or dust that occurs naturally. It was first intentionally produced for use as a white pigment in 1923.
R-895:
The surge in demand for interior and exterior paints and use of plastic across various end-use industries drive the global Lithopone market. Lithopone white pigment is used in paints and coating systems that find applications in residential and industrial landscapes. Hence, as the construction & building sector flourishes, the demand for building and architectural materials such as paints and coatings will increase. This trend is conducive for the Lithopone market growth. In addition, white plastic materials are increasingly being used in consumer products. Developments in plastic forming technology is anticipated to indirectly boost plastic production, thus, increasing the demand for white pigments during the forecast period.
if you compare the levels—which went as high as 50,000 milligrams/killigrams per day— to what humans are actually exposed to, we're talking orders of magnitude. It was a huge amount, Norbert Kaminski, PhD, a professor of pharmacology & toxicology and director of the Center for Research on Ingredient Safety at Michigan State University told Health.
Pure PVB is non-toxic and harmless to human body. In addition, ethyl acetate or alcohol can be used as solvent, so PVB is widely used in printing ink of food containers and plastic packaging in European and American countries.
Storage safety properties
PVB can be stored for two years without affecting its quality as long as it is not in direct contact with water; PVB shall be stored in a dry and cool place and avoid direct sunlight. Heavy pressure shall be avoided during PVB storage.
Solubility
PVB is soluble in alcohol, ketone, ester and other solvents. The solubility of various solvents changes according to the functional group composition of PVB itself. Generally speaking, alcohol solvents are soluble, but methanol is more insoluble for those with high acetal groups; The higher the acetal group, the easier it is to dissolve in ketone solvents and ester solvents;
PVB is easily soluble in cellosolve solvents; PVB is only partially dissolved in aromatic solvents such as xylene and toluene; PVB is insoluble in hydrocarbon solvents.
Viscosity characteristics of PVB solution
The viscosity of PVB solution is greatly affected by the formula of solvent and the type of solvent; Generally speaking, if alcohol is used as solvent, the higher the molecular weight of alcohol, the higher the viscosity of PVB solution;
Aromatic solvents such as xylene and toluene and hydrocarbon solvents can be used as diluents to reduce the viscosity of PVB solution; The effect of PVB chemical composition on viscosity is summarized as follows: under the same solvent and the same content of each base, the higher the degree of polymerization, the higher the solution viscosity; Under the same solvent and the same degree of polymerization, the higher the acetal group or acetate group, the lower the solution viscosity.
Dissolution method of PVB
Where mixed solvents are used, the dissolution step is to first put aromatic solvents (such as xylene, toluene, etc.) or ester solvents (such as n-butyl acetate, ethyl acetate, etc.) into the mixing, slowly put PVB into the mixing, and then add alcohol solvents (such as n-butanol, ethanol, etc.) after PVB is dispersed and expanded,
At this time, the dissolution time can be shortened by heating; Using this dissolution method, the formation of lumpy PVB can be avoided (because the dissolution time will be several times after the formation of lumpy PVB), so the dissolution speed can be accelerated. Generally, the ratio of aromatic and alcohol solvents is 60 / 40 ~ 40 / 60 (weight ratio), and PVB solution with low viscosity can be prepared.
The solvent composition contains 2 ~ 3wt% water, which can improve the hydrogen bonding strength of alcohol solvents and help the solubility of PVB.
Processing properties
Although PVB resin is a thermoplastic, it has little processability before plasticizer is added. Once plasticizer is added, its processability is very easy.
The purpose of general coatings and adhesives is to change the resin characteristics by adding plasticizers to meet the application requirements, such as film softness, reducing the TG point of the resin, reducing the heat sealing temperature, maintaining low-temperature softness, etc.
Compatibility
PVB can be compatible with a variety of resins, such as phenolic resin, epoxy resin, alkyd resin and MELAMINE resin.
B-08sy, b-06sy and b-05sy with high acetal degree can be mixed with nitrocellulose in any proportion. PVB and alkyd resin are partially compatible. General PVB is compatible with low molecular weight epoxy resin, while high molecular weight epoxy resin needs PVB with high acetal degree to be compatible with each other.
ZnSO4 – BaS ➔ BaSO4*ZnS
Titanium dioxide has also been classified as a possible human carcinogen by the International Agency for Research on Cancer, which has caused concern about its use in food products. This classification, however, is currently based on limited evidence from animal studies that involved the inhalation of titanium dioxide particles that increased the risk of lung cancer.
Titanium dioxide is a widely used substance in various industries due to its versatility and unique properties. As a result, there are numerous manufacturers of titanium dioxide around the world, catering to the different needs of their customers.
The principal natural source of titanium dioxide is mined ilmenite ore, which contains 45-60 percent TiO2. From this, or an enriched derivative (known as titanium slag), pure TiO2 can be produced using the sulphate or chloride process.
The skin of an adult person is, in most places, covered with a relatively thick (∼10 μm) barrier of keratinised dead cells. One of the main questions is still whether TiO2 NPs are able to penetrate into the deeper layers of the skin. The majority of studies suggest that TiO2 NPs, neither uncoated nor coated (SiO2, Al2O3 and SiO2/Al2O3) of different crystalline structures, penetrate normal animal or human skin. However, in most of these studies the exposures were short term (up to 48 h); only few long-term or repeated exposure studies have been published. Wu et al.83 have shown that dermal application of nano-TiO2 of different crystal structures and sizes (4–90 nm) to pig ears for 30 days did not result in penetration of NPs beyond deep epidermis. On the other hand, in the same study the authors reported dermal penetration of TiO2 NPs with subsequent appearance of lesions in multiple organs in hairless mice, that were dermal exposed to nano-TiO2 for 60 days. However, the relevance of this study for human exposure is not conclusive because hairless mice skin has abnormal hair follicles, and mice stratum corneum has higher lipid content than human stratum corneum, which may contribute to different penetration. Recently Sadrieh et al. performed a 4 week dermal exposure to three different TiO2 particles (uncoated submicron-sized, uncoated nano-sized and coated nano-sized) in 5 % sunscreen formulation with minipigs. They found elevated titanium levels in epidermis, dermis and in inguinal lymph nodes, but not in precapsular and submandibular lymph nodes and in liver. With the energy dispersive X-ray spectrometry and transmission electron microscopy (TEM) analysis the authors confirmed presence of few TiO2 particles in dermis and calculated that uncoated nano-sized TiO2 particles observed in dermis represented only 0.00008 % of the total applied amount of TiO2 particles. Based on the same assumptions used by the authors in their calculations it can be calculated that the total number of particles applied was 1.8 × 1013 /cm2 and of these 1.4 x107/cm2 penetrated. The surface area of skin in humans is around 1.8 m2 and for sun protection the cream is applied over whole body, which would mean that 4 week usage of such cream with 5 % TiO2 would result in penetration of totally 2.6 × 1010 particles. Although Sadrieh et al.concluded that there was no significant penetration of TiO2 NPs through intact normal epidermis, the results are not completely confirmative.
Now if your an Aussie, I am sure you have seen the Bluescope Steel add about how it stands up to the test of time & the elements – but a little bit of titanium dioxide & it’s all over!!!
Nano, or ultrafine, TiO2 comprises primary particles sized less than 100nm. In this grade, titanium dioxide is transparent (colourless) and boasts improved UV scattering and absorbing properties compared with larger particle-size pigmentary TiO2.