It is well known that for most PVC products, a certain amount of calcium carbonate is added. As an inexpensive filler, calcium carbonate can be added in small amounts to reduce costs on the one hand, and to improve the modulus, heat resistance and dimensional stability of the product on the other hand, and even some active nano calcium can play an enhancing role. However, with the increase of calcium powder content, the quality of PVC products tends to decrease and the density also increases.
The effect of calcium powder content on the density of PVC products
Calcium powder content (KG) Density of PVC product
25 1.505
50 1.615
75 1.692
100 1.751
125 1.791
150 1.894
175 1.920
200 1.982
225 2.048
250 2.058
275 2.106
300 2.145
Usually the light calcium carbonate refers to the ordinary products in line with the national standard GB4794-84 standard, the density of light calcium is 2.4~2.7g/cm3, settling volume 2.4-2.8mL/g, its long diameter is 5~12μm, short diameter is 1~3μm, the average particle size is 2~3μm. industrial light calcium production method is dominated by the carbonization method, namely: CaCO3 limestone - H2O - Ca(OH)2 quicklime - CO2 - CaCO3 light calcium △ - CaO limestone - H2O - Ca(OH)2 slaked lime - CO2 - CaCO3 light calcium
Bicarbonate can be made from natural calcium carbonate minerals such as calcite, marble and chalk by grinding and grading. Nowadays, calcite is mostly used as raw material for heavy calcium carbonate used in plastics. Physical properties of calcite: density 2.60~2.75g/cm3, sink volume 1.1-1.4mL/g, hardness (Mohs) 3, solubility (18℃) 0.0013g/100g water, decomposition temperature 900℃. Heavy calcium carbonate used to be called single fly powder (200 mesh), double fly powder (320 mesh), four fly powder (400 mesh), and calcite powder.
Generally with light calcium plastic surface is a little smoother, and the density will be lower; using heavy calcium, plastic processing fluidity to be better, and smaller particle size of heavy calcium filled plastic performance is also better.
The relationship between pipe meter weight and density
Meter weight = (outside diameter - wall thickness) X wall thickness X 3.14 X density / 1000
Density = meter weight / (outside diameter - wall thickness) X wall thickness X 3.14/1000
With the density reference table, the actual production meter weight can be weighed and obtained, and according to the wall thickness and outer diameter, it is easy to infer the calcium powder content in the PVC pipe.