A method for preparing low-boron volatilization medical glass

Abstract

The present invention discloses a low-boron volatilization pharmaceutical glass and a preparation method thereof, comprising the following components in weight percentage: 55-70wt% SiO2, 15-20wt% Al2O3, 0.1-5wt% B2O3, 3-8wt% Na2O, 0.5-5.5wt% K2O, 0.5-6wt% CaO, 0.5-6wt% BaO, 0.1-2wt% P2O5, 0.1-3wt% ZrO2, 0-2% NaCl, 0-2% CeO2, 0-2% NaNO3, and then adopting multi-stage gradient melting molding. Compared with the traditional neutral borosilicate glass, the present invention greatly reduces the boron volatilization, the glass composition is stable, and the thermal expansion coefficient is 4.6-5.2×10 –6 / ℃, water resistance and acid resistance reach level 1, alkali resistance reaches level 2, the finished product rate is high quality and stable, the process is simple and the cost is low, which is suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of medical glass, and in particular to a method for preparing medical glass with low boron volatilization. Background Art

[0002] China attaches great importance to drug supervision. In May 2020, injections were officially included in the consistency evaluation, stipulating that the quality and performance of the packaging materials and containers used for injections shall not be lower than those of the reference preparations to ensure that the quality of the drugs is consistent with the reference preparations. At the same time, on the one hand, the demand for vaccines and key drugs has surged, and on the other hand, the production capacity of borosilicate glass tubes is insufficient, which has brought a great impact on the entire glass pharmaceutical packaging material industry chain. In addition, with the development of the pharmaceutical industry and the enrichment of pharmaceutical products, more acidic or alkaline drugs have appeared, and the problem of delamination caused by the incompatibility of drugs and glass is increasing. Therefore, it is necessary to research and develop pharmaceutical glass with higher chemical stability and thermal stability to ensure the safety of drugs and protect people's lives and health.

[0003] Pharmaceutical glass has many excellent properties, such as transparency, smoothness, barrier properties, chemical stability, temperature resistance, light blocking, compatibility, and regeneration. It is an irreplaceable packaging container for many pharmaceutical products and biological preparations, and is widely used in the packaging of vaccines, high-end infusions, antibiotics, general powders, freeze-dried products, blood, biological preparations, and other pharmaceuticals.

[0004] The basic component of pharmaceutical glass is borosilicate glass, which has good chemical stability. When containing chemical reagents and medicines, the amount of alkali ions leached from the glass is very small. Long-term contact with the liquid medicine will not cause changes in the pH value, and there will be no precipitation or glass chips falling off. Pharmaceutical glass has the following advantages: (1) Low expansion coefficient, strong resistance to extreme cold and heat, suitable for freeze-dried products. (2) Not easy to explode during processing, strong impact resistance. (3) Good chemical stability, high acid, alkali and water resistance.

[0005] However, due to the high boron content in borate glass, B2O3 is very easy to volatilize during the melting process, and the general volatilization amount is 10-15%. It will not only consume a large amount of raw materials, but also easily corrode refractory materials and shorten the service life of the melting furnace. This will also cause the actual composition of the glass to be very different from the designed composition, and it is difficult to control the B2O3 content in the glass, thus affecting the physical and chemical properties of the glass. In addition, the volatilization of B2O3 will still cause stratification of the glass liquid in the kiln, and stripes will still appear on the surface of the glass liquid, which will cause uneven melting of the glass, and defects such as bubbles and stripes will easily appear during the tube drawing process, making it difficult to control medical glass tubes and bottle making, resulting in a decrease in the yield rate and product quality. Summary of the invention

[0006] The purpose of the present invention is to solve the problem that boron volatilization in the preparation process of pharmaceutical glass easily causes defects, and to provide a method for preparing pharmaceutical glass with low boron volatilization.

[0007] To achieve the purpose of the present invention, the present invention adopts the following technical solutions:

[0008] A method for preparing low-boron volatilization medical glass, characterized by comprising the following steps:

[0009] S1. Prepare batch materials: according to weight percentage, take 55-70wt% SiO2, 15-20wt% Al2O3, 0-7wt% B2O3, 0-5wt% Li2O, 1-8wt% Na2O, 0.5-5.5wt% K2O, 0.5-6wt% CaO, 0.5-6wt% BaO, 0.1-3wt% ZrO2, 0.1-2wt% TiO2, 0-2.5% NaCl, 0-2% CeO2, and 0-2.5% NaNO3 as raw materials, wherein the value of SiO2+Al2O3 is 73-87%, the value of Li2O+Na2O+K2O is 5-12.5%, and the value of NaCl+CeO2+NaNO3 is 0.05-3%.

[0010] S2. Glass melting: the batch materials prepared in S1 are mixed and put into a crucible, and a multi-stage gradient melting process is adopted to form a clarified glass liquid. The glass liquid is stirred evenly and cooled to form, and then annealed at 550° C. to obtain a pharmaceutical glass.

[0011] In the present invention, the multi-stage gradient melting system in S2 is as follows: (1) heating stage: starting from room temperature to 1050-1150°C, the heating time is 1.5-2.5h; (2) melting stage: continuing to heat to 1550-1640°C, the heating time is 2-3h; (3) holding stage: holding at 1550-1640°C, the holding time is 1-4h; (4) annealing stage: transferring to 550°C for annealing, the holding time is 0.5-2.5h.

[0012] In the present invention, SiO2 is the main component of glass, and SiO2 is one of the main determinants of glass melting process performance and physical and chemical properties. If the content of SiO2 is too little, the chemical stability of the medical glass tube decreases, increasing the potential safety hazard of glass flakes when containing medicines. On the other hand, if the content of SiO2 is too much, the melting temperature and processing temperature increase significantly, the glass is difficult to clarify, and the manufacturing difficulty and production cost are increased. The SiO2 content of the medical glass is 55-70wt%.

[0013] In the present invention, Al2O3 helps to enhance the density of the glass network structure and improve the chemical stability of the glass. Too much Al2O3 will increase the difficulty of melting and clarifying the glass. The Al2O3 content of the pharmaceutical glass is 15-20wt%.

[0014] In the present invention, B2O3 can reduce the brittleness of glass and improve the chemical stability of glass. Meanwhile, B2O3 is also a good fluxing agent, which can greatly reduce the melting temperature of glass and is also beneficial to the vitrification process. The content of B2O3 in the pharmaceutical glass is 0-7wt%.

[0015] In the present invention, Na2O and K2O can reduce the viscosity of glass, and appropriately increasing the alkali metal content can promote the melting process of glass and reduce the melting temperature, but too much content will reduce the chemical stability of glass. The content of Na2O in the pharmaceutical glass is 1-8wt%, and the content of K2O is 0.5-5.5wt%.

[0016] In the present invention, CaO and BaO can be adjusted to reduce high temperature viscosity and improve glass melting performance without reducing the glass strain point, but excessive content will reduce the chemical stability of the glass. The CaO content of the pharmaceutical glass is 0.5-6wt%, and the BaO content is 0.5-6wt%.

[0017] In the present invention, ZrO2 can improve the chemical stability of glass, especially alkali resistance. If the content of ZrO2 is too little, it cannot play the role of improving the chemical stability of glass; if it is too much, it will increase the viscosity of glass, increase the melting temperature, and increase the difficulty of melting. The content of ZrO2 in the pharmaceutical glass is 0.1-3wt%.

[0018] In the present invention, the introduction of P2O5 can reduce the melting temperature and forming temperature of the glass and increase the thermal expansion coefficient, but excessive introduction may cause the glass to crystallize and reduce chemical stability. The content of P2O5 in the pharmaceutical glass is 0.1-2wt%.

[0019] In the present invention, the pharmaceutical glass preferably comprises the following components in weight percentage: 57–68wt% SiO2, 17–20wt% Al2O3, 0–5wt% B2O3, 0–3wt% Li2O, 3–8wt% Na2O, 0.5–4wt% K2O, 0.5–4wt% CaO, 0.5–4wt% BaO, 0.1–2wt% ZrO2, 0–2% NaCl, 0–1.5% CeO2, and 0–2% NaNO3, wherein the value of SiO2+Al2O3 is 75-85%, the value of Li2O+Na2O+K2O is 6–12%, and the value of NaCl+CeO2+NaNO3 is 0.05–2%.

[0020] In the present invention, the medical glass is characterized in that the thermal expansion coefficient (20-300°C) of the low-boron volatilization medical glass is 4.6-5.2×10 －6 / ℃, water resistance, acid resistance reach level 1, alkali resistance reach level 2, operating temperature T w <1240℃, melting temperature T m <1710℃.

[0021] In the present invention, by limiting (Na2O+K2O+CaO+BaO) / Al2O3 to 0.6-1.05, B2O3 / (ZrO2+P2O5) to 0.03-3.5, (CaO+BaO) / (Na2O+K2O) to 0.1-1.25, and adjusting the ratio of alkali metal, alkaline earth metal and network external oxide glass composition, boron volatilization can be effectively inhibited, and P2O5 is introduced to reduce the viscosity of the glass, reduce the melting temperature and the forming temperature, and increase the thermal expansion coefficient. A multi-stage gradient melting process is adopted to reduce the temperature of the heating section as much as possible, shorten the heating section time, reduce the boron volatilization reaction amount and reaction time, extend the melting section and the insulation section, reduce the influence of the increase in glass viscosity and the increase in melting temperature caused by the composition, so that the glass liquid is fully melted and the glass melting is guaranteed to be uniform.

[0022] The advantages of the present invention are that compared with traditional medical glass, the boron content is greatly reduced, the tube drawing and bottle making are more stable, the product quality and yield rate are improved, and the thermal expansion coefficient and melting temperature are guaranteed to meet the use and preparation requirements, the water resistance and acid resistance reach level 2, and the alkali resistance reaches level 1. The multi-stage melting process of the present invention further reduces the boron volatilization amount, can ensure that the glass liquid is fully melted and melted evenly, and the preparation process operation process is simple, the cost is low, and it is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The thermal expansion curves of the pharmaceutical glasses of Examples 1, 4 and 8 of the present invention;

[0024] Figure 2 1 is the high temperature viscosity curve of the pharmaceutical glass of Examples 1, 4 and 8 of the present invention. Implementation

[0025] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with examples, but the present invention is not limited to the following embodiments.

[0026] A method for preparing a low-boron volatilization medical glass, wherein the medical glass comprises the following components in weight percentage: 55-70wt% SiO2, 15-20wt% Al2O3, 0-7wt% B2O3, 0-5wt% Li2O, 1-8wt% Na2O, 0.5-5.5wt% K2O, 0.5-6wt% CaO, 0.5-6wt% BaO, 0.1-2wt% % P2O5, 0.1-3wt% ZrO2, 0-2% NaCl, 0-2% CeO2, 0-2% NaNO3, wherein SiO2+Al2O3 value is 75-85%, (Na2O+K2O+CaO+BaO) / Al2O3 is 0.6-1.05, B2O3 / (ZrO2+P2O5) value is 0.03-3.5, (CaO+BaO) / (Na2O +K2O) is 0.1-1.25, and NaCl+CeO2+NaNO3 value is 0.5-2%. The prepared batch materials are mixed according to this composition and put into a crucible, and a multi-stage gradient melting process is adopted to form a clarified glass liquid. After the glass liquid is stirred evenly and cooled to form, it is annealed at 550°C to obtain a pharmaceutical glass. The components and properties of the obtained glass samples of Examples 1 to 14 and Comparative Examples 1 to 4 are shown in Tables 1, 2, and 3.

[0027] The boron volatilization rate is calculated based on the change in boron content before and after glass melting, and the unit is %.

[0028] The thermal expansion coefficient of glass at 20-300°C was measured using a dilatometer according to GB / T 7962.16-2010, with the unit being ×10 －6 / ℃.

[0029] The high temperature viscosity-temperature curve of glass was measured using a rotary high temperature viscometer, referring to ASTM C-965, where 10 1 The temperature corresponding to the viscosity of Pa·s is the melting temperature T m , 10 2.8 The temperature corresponding to the viscosity of Pa·s is the operating temperature T w , unit is ℃

[0030] Water resistance is tested according to YBB00252003 and is divided into levels 1, 2 and 3.

[0031] Acid resistance is tested according to YBB00342004 and is divided into levels 1, 2, and 3.

[0032] Alkali resistance is tested according to YBB00352004 and is divided into levels 1, 2 and 3.

[0033] Table 1 Components and properties of Examples 1 to 7

[0034]

[0035] Table 2 Components and properties of Examples 8 to 14

[0036]

[0037] Table 3 Components and properties of Comparative Examples 1 to 4

[0038]

[0039] In Examples 1-14 and Comparative Examples 1-4, the boron volatilization rate is reduced from 10% to 8%~5%. It can be seen that adjusting the ratio of alkali metal, alkaline earth metal and network external oxide glass composition can effectively inhibit boron volatilization. At the same time, in order to control the thermal expansion coefficient of glass and the glass melting temperature, P2O5 is introduced to effectively reduce the glass viscosity, melting temperature and molding temperature. It can be clearly seen from the Examples and Comparative Examples that the boron content of the Examples is low, resulting in a low boron volatilization rate of 8%~5%.

[0040] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form; any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the above disclosed methods and technical contents without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing low-boron volatilization medical glass, characterized in that: The following steps are involved: S1. Prepare a batch material according to the following weight percentages: 55–70wt% SiO2, 15–20wt% Al2O3, 0–7wt% B2O3, 1–8wt% Na2O, 0.5–5.5wt% K2O, 0.5–6wt% CaO, 0.5–6wt% BaO, 0.1–2wt% P2O5, 0.1–3wt% ZrO2, 0–2.5% NaCl, 0–2% CeO2, and 0–2.5% NaNO3; Among them, the SiO2+Al2O3 value is 75–85%, (Na2O+K2O+CaO+BaO) / Al2O3 is 0.6–1.05, B2O3 / (ZrO2+P2O5) value is 0.03–3.5, (CaO+BaO) / (Na2O +K2O) is 0.1–1.25, NaCl+CeO2+ NaNO3 values ​​are 0.5–2%; S2, glass melting: the batch materials prepared in S1 are mixed and put into a crucible, and a multi-stage gradient melting process is adopted to form a clear glass liquid, the glass liquid is stirred evenly and cooled to form, and then annealed at 550°C to obtain a pharmaceutical glass; The multi-stage gradient melting system is as follows: (1) heating stage: starting from room temperature to 1050-1150°C, the heating time is 1.5-2.5 hours; (2) melting stage: continuing to heat to 1550-1640°C, the heating time is 2-3 hours; (3) holding stage: holding at 1550-1640°C, the holding time is 1-4 hours; (4) annealing stage: transferring to 550°C for annealing, the holding time is 0.5-2.5 hours.

2. The method for preparing a low-boron volatilization medical glass according to claim 1, characterized in that: The raw materials include the following components in weight percentage: 57–68wt% SiO2, 17–20wt% Al2O3, 0–5wt% B2O3, 0–3wt% Li2O, 3–8wt% Na2O, 0.5–4wt% K2O, 0.5–4wt% CaO, 0.5–4wt% BaO, 0.1–1.5wt% P2O5, 0.1–2.5wt% ZrO2, 0–2% NaCl, 0–1.5% CeO2, and 0–2% NaNO3. Among them, SiO2+Al2O3 is 75–83%, (Na2O+K2O+CaO+BaO) / Al2O3 is 0.65–1.0, B2O3 / (ZrO2+P2O5) is 0.05–3.25, (CaO+BaO) / (Na2O +K2O) is 0.15–1.2, NaCl+CeO2+NaNO3 is 0.5–1.75%.

3. A method for preparing a low-boron volatilization medical glass according to claim 1 or 2, characterized in that: The thermal expansion coefficient of the medical glass at 20°C to 300°C is 4.6 to 5.2×10 －6 / ℃, water resistance, acid resistance reach level 1, alkali resistance reach level 2, operating temperature T w <1240℃, melting temperature T m <1710℃.

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