How are high borosilicate glass bottles made?

The production of high borosilicate glass bottles generally goes through five stages: batching, melting, forming, annealing and post-processing.

Ingredient preparation and melting are the thresholds. After the raw materials (such as quartz sand, borax, soda ash, etc.) are precisely weighed according to the formula, they are sent into a kiln at a temperature above 1500℃ for high-temperature melting. The melting temperature of high borosilicate is higher than that of sodium-calcium glass, and the viscosity of the glass liquid is greater. This poses challenges to the lifespan of the kiln and temperature control, which is also one of the reasons for its high cost.

There are mainly two routes for forming: mechanical forming is suitable for large-scale production of standard-diameter bottle shapes, featuring high efficiency and good dimensional consistency; Manual blowing is suitable for irregular-shaped bottles, thick-walled bottles and small-batch customization. It has a strong artistic sense but limited production capacity. After forming, the glass bottle must be cooled down slowly in an annealing furnace to eliminate internal stress. If this step is not done well, the glass bottle may look intact, but in reality, it will crack when exposed to temperature differences.

Post-processing determines the "appearance level" : Processes such as sandblasting, spraying, silk-screen logo printing, decal application, and electroplating can all achieve brand expression on the bottle body. It should be noted that the compatibility of high borosilicate glass with glazes and inks is different from that of soda-lime glass. After printing, it needs to be sintered at high temperatures to ensure adhesion.

For purchasers engaged in foreign trade, it is recommended to focus on four key matters when inspecting goods

The first is capacity and dimensional tolerance. High borosilicate molding is difficult. The allowable deviations of bottle capacity, diameter and wall thickness should be agreed upon with the factory in advance and the measured data should be verified.

The second is the temperature difference resistance test. The factory is required to provide a third-party test report, or a "boiling water - ice water" cycle test can be conducted on-site on the small sample to directly examine the thermal shock resistance.

The third is the quality of the inner surface. Check if there are any stones, bubbles or cracks in the bottle. These defects may pose a risk of bottle explosion after filling.

The fourth is packaging and transportation. When glass bottles are exported, they have to face the bumpy sea transportation. The inner lining partitions, stretch films and the pressure-bearing grades of the cartons all need to be designed in accordance with the "shatterproof" standard. At the same time, confirm in advance the food contact certification requirements of the destination market (such as FDA, LFGB, etc.).