Medical glass is mainly used in the manufacture of medical equipment, medical containers, such as medical ampoules, all-glass syringes, thermometers and so on. Commonly used glass composition system is quartz glass, high silica glass. Borosilicate glass, aluminosilicate glass and sodium silicate glass. As some of these systems have been described in detail in other chapters, here mainly describes borosilicate neutral glass. The pH of the solution remains constant and is therefore referred to as "neutral glass". Neutral glass is used to prepare glass instruments, chemical equipment, medical ampoules, syringes and medicinal containers with high chemical stability requirements.

   In order to reduce the thermal expansion coefficient of neutral glass, improve the mechanical strength and toughness, increase the chemical stability and make the glass easy to melt, can be introduced in the neutral glass B20. , Good quality neutral glass contains 6% (mass fraction) above the Bzos. However, since boron ions can form boron trioxide or boron tetrahedron in the glass structure, the effect of these two coordination states on the structure of the glass network is opposite. The basic composition of the neutral glass is borosilicate glass, which has good Of chemical stability, in the possession of chemical reagents and drugs, the glass of alkali ions leaching is very small.

   Therefore, under certain conditions, the partial properties of the glass will change abnormally with the increase of the content of B20s, the so-called "boron anomaly".

Borosilicate glass is one of the characteristics of easy to produce phase separation, so that the chemical resistance of glass significantly decreased. Although the appearance of glass can not be observed with the visual changes, the introduction of CaO to improve the chemical stability of the glass is not too much, its more important role is to reduce the high temperature of the glass viscosity, so that the glass is easy to melt; but short-term use of its surface "Hairy". But also in the glass to introduce a certain amount of divalent metal oxides, such as CaO, MgO, ZnO, BaO, used to replace NazO. The effect of these oxides on the chemical stability of the glass is arranged in the following order: ZnO> BaO> MgO> CaO.

   When using this glass containing a neutral solution of pH 7, the heat treatment at a certain temperature or stored for a long time in order to improve the chemical stability of neutral glass, chemical stability requirements for the high neutral glass , A slight separation can reduce the chemical stability of the glass. In order to prevent the occurrence of glass phase separation, can be introduced in the composition of 5% (mass fraction) around the A1203. Excessive A1203 content will increase the glass viscosity, melting point increased, the process performance deterioration.

   At the same time can improve the low temperature of glass, the glass forming temperature range is reduced, is conducive to improving the speed and reduce the length of the runway. The introduction of a small amount of MgO in the glass composition instead of part of the CaO can reduce the glass crystallization temperature and improve the chemical stability. But easy to produce magnesium silicate off, so most of the composition of neutral glass does not contain MgO. However, the introduction of CaO will reduce the elasticity of the glass, the product is brittle. CaO is rarely used in borosilicate glass.

   Taizhou thousands of Johnson Plastic Co., Ltd. is a commitment to the medical aspects of research and development, production and sales as one of the modern enterprise! The company mainly engaged in: pet chip syringes, medical silicone O-ring, medical medical plastic products!