Multiple-use drinking straws and their production
The present invention deals with a tube ( 1 ) with a tube base body ( 2 ) which consists of glass, wherein at least the inside of the tube base body ( 2 ) is at least partially covered a hydrophobic coating ( 3 ). The use of such tubes ( 1 ) as drinking straws leads to multiple use, ecologically friendly drinking straws which meet hygienic requirements and have a good cleanability. The present invention also deals with a process for producing such tubes.
1 . Process for producing a coated glass tube comprising the following steps:
a) providing a glass tubular base body which is hydrophobized per se;
b) providing a solution or suspension containing a hydrophobic polymer material;
c) contacting the glass tubular base body and the solution or suspension provided in step b) with at least an inner surface of the glass tubular base body by immersing the glass tubular base body in the solution or suspension;
d) optionally drying the glass tubular base body obtained in step c);
e) heat treating the glass tubular base body obtained in step c),
wherein the hydrophobized glass tubular base body is a silanized glass tubular base body.
2 . Process according to claim 1 , wherein the solution provided in step b) is a solution containing 0.5 to 10% by weight of hydrophobic polymer material, and/or wherein the hydrophobic polymer material is selected from the group consisting of silanes, silicone oils, halogenated hydrocarbons and inorganic-organic hybrid polymers.
3 . Process according to claim 2 , wherein the solution provided in step b) is an aqueous solution containing 0.5 to 10% by weight of hydrophobic polymer material dissolved or dispersed in water.
4 . Tube obtained by the process of claim 2 for use as a drinking straw with a tube base body which is made of or consists of glass,
wherein at least an inside of the glass tube base body is at least partially covered with a hydrophobic coating,
wherein the glass tube base body per se is hydrophobized, at least inside portions of the glass tube base body are at least partially covered by the hydrophobic coating,
wherein the coating additionally contains an antibacterial agent, and
wherein the hydrophobized glass tube base body is a silanized glass tube base body.
5 . Tube according to claim 4 , wherein the inside of the tube base body is fully covered with the hydrophobic coating.
6 . Tube according to claim 4 , wherein the silanized glass tube base body is made of soda lime glass, borosilicate glass or quartz glass.
7 . Tube according to claim 4 , wherein the coating comprises a hydrophobic polymeric material, wherein the hydrophobic polymeric material is selected from the group consisting of silanes and silicone oils.
8 . Tube according to claim 4 , wherein the antibacterial agent is selected from the group consisting of silver, copper, and their compounds.
9 . Tube according to claim 8 , wherein the antibacterial agent is selected from the group consisting of elemental silver, colloidal silver, or silver nitrate.
10 . Tube according to claim 4 , the silanized glass tube base body having an inner diameter between 3 and 10 mm, and/or a wall thickness between 0.8 and 3 mm, and/or a length between 100 and 350 mm, and/or wherein the coating has a thickness of between 0.1 μm and 1000 μm.
11 . Tube according to claim 4 , the silanized glass tube base body having a straight cylindrical shape or an angled cylindrical shape or a kinked cylindrical shape.
12 . Tube according to claim 4 , wherein the coating comprises a hydrophobic polymeric material, wherein the hydrophobic polymeric material is selected from the group consisting of halogenated hydrocarbons and hydrophobic inorganic-organic hybrid polymers.
13 . Process according to claim 1 , the solution in step b) further containing an antibacterial agent.
14 . Process according to claim 13 , wherein the antibacterial agent is selected from the group consisting of silver, copper and their compounds.
15 . Process according to claim 14 , wherein the antibacterial agent is selected from elemental silver, colloidal silver, or silver nitrate.
16 . Process according to claim 1 , wherein in step d) a temperature of at least 200° C. is used, and/or wherein the heat treatment in step d) is carried out for at least 5 minutes.
17 . Process according to claim 1 , wherein step c) comprises immersing the silanized glass tubular base body in the solution provided in step b) or vaporizing the silanized glass tubular base body with the solution provided in step b) or surface diffusion.