Talc powder, which is used as a filler, may be second only to calcium carbonate, and is also a more confusing type of filler. First, let's look at the effect of a falling stone powder on the filling masterbatch:
1. The talcum powder is flake-shaped, so it has higher rigidity and good reinforcement effect.
2. Talc has a nucleating effect on polypropylene, while other filler materials have no obvious effect.
A set of data illustrates the above:
The tensile strength of the PP base material was 33.7 MPa, and after filling PP with 20% talc, the tensile strength was 38 MPa.
Another set of data:
15% talc filled with PP can increase the flexural modulus from 1500MPa to 4300MPa. Of course, the latter data is somewhat idealized, but it also explains the filling enhancement of talc to some extent. However, few people can do so now. Why?
The reason is that the problem lies in the talcum powder used. Few people really understand what kind of talcum powder they use. In addition to the number of items and prices, will they care about other factors? This is the key.
chemical composition:
The main component of talcum powder: talc
CASNo.: 14807-96-6
Molecular weight: 260.8617
Talc powder chemical composition: hydrous magnesium silicate
Molecular formula: 3MgO•4Si02•H2O
The theoretical silica content is 63.49%, and the natural talc is crushed, ground, and classified to form talc.
Chemical properties:
The chemical composition of talc in China is as follows: Si0258%-62%, Mg08%-31%, and the loss on ignition is 4.5%~6%.
Other impurities: CaO1.5%, Fe2O30.04%, A12030.3% or so.
Do you know why the composition of talcum powder is analyzed? This is the key to the problem. Many people may not know the most critical characterization parameters of talc. The characterization parameters of talc powder generally use SiO2+Mg0, which indicates the purity and whiteness of talcum powder. The best talcum powder is about 90%.
Application difference:
The standard for measuring talcum powder is SiO2+MgO. The best is 91%. There are two kinds of domestic minerals, one is 6:3, the other is 3:6, and the highest whiteness can reach 98 degrees. Can the talc used achieve this whiteness?
So what is the status of talcum powder on the market? In general, the talc powder sold on the market is usually from 10% to 47%, and the amount of talc is 61%. This is a high-end talcum powder. Some commercial talcum powder does not even Contains silica.
So where is the difference between different talcum powder applications?
Silica (SIO2) content | 27% | 47% | 61% |
Tensile strength (MPa) | 20.1 | 23.52 | 26.77 |
Impact strength (KJ/m2) | 7.2 | 8.9 | 10.6 |
Bending strength (MPa) | 23.24 | 29.13 | 37.24 |
Flexural modulus (MPa) | 1307 | 1547 | 2210 |
I hope that the above data analysis will help your formula.
Source: Network
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