JPH01160846A - Method for preventing strength of glass bottle bottom from deteriorating - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for preventing strength deterioration of the bottom of a glass bottle by coating the bottom of the bottle with a water-soluble resin to form a film-like coating of the resin. It is something.

(Prior art) Generally, in order to prevent scratches and scratches on the outer surface of glass bottles during inspection and packaging processes after glass bottles are formed, surface treatment is performed at the entrance or exit of the lehr after glass bottles are formed. The process performed at the inlet is called hot-end coating, and the process performed at the outlet is called cold-end coating. In hot-end coating, a thin film of metal oxide such as tin dioxide or titanium dioxide is formed on the external surface, and in cold-end coating, a thin film of an organic compound such as water-insoluble polyethylene wax is formed.

However, cold coating using conventional water-insoluble coating liquids has a small scratch prevention effect, and unless used in combination with hot end coating, sufficient scratch prevention effects cannot be achieved. However, since the thin film formed by the coating did not cover the outer surface of the glass bottle in the form of a film, it had little effect on scratch resistance against sharp protrusions. (Special Publication No. 42-1758) In particular, scratches on the bottom of the bottle are known to be the biggest cause of strength deterioration.
It has been desired to develop a method for preventing deterioration of the strength of the bottom of a glass bottle, which is more effective in preventing scratches than conventional combination coating methods.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems and improves the strength of the bottom of the glass bottle by combining it with a hot-end coating (but still providing sufficient scratch-prevention effects). It was completed with the aim of providing a method for preventing deterioration.

(Means for solving the problems) The present invention is intended to solve the above problems,
After passing through a slow cooling furnace, a water-soluble resin is applied to the bottom of the glass bottle, which is in the temperature range of 50 to 150°C, and then the water-soluble resin is thermally cured using the heat retained by the bottle to form a film-like coating only on the bottom of the bottle. It is characterized by forming.

The above coating resins can be broadly classified into solvent-based, solvent-free, radiation-curable, and water-based resins.The water-soluble resins used in the present invention include alkyds, polyesters, acrylics, epoxies, etc. It is a water-based resin composed of a polymer that can be dissolved. When this water-based resin is thermally cured, it can form a film-like coating that is strong and adheres to the surface of a glass bottle due to its film-forming effect. The thickness of the film-like coating film formed on the bottom of the glass bottle is preferably about 10 μm.

The temperature range of glass bottles to which water-soluble resin should be applied is 50 to 15
The temperature is preferably in the range of 0°C, and the water-soluble resin is thermally cured by the heat retained in the glass bottle. If the temperature is below 50℃, it will take time to dry and harden the water-soluble resin;
If this is the case, there is a risk that the bottle will break due to thermal shock due to the temperature difference with the coating liquid, and there is also a risk that foaming will occur within the coating film due to rapid drying and hardening. Further, by providing an underspray coating process on the conveyor after passing through the slow cooling furnace, online coating processing becomes possible.

In glass bottles with a film-like coating formed on the bottom as described above, unlike cases with conventional cold-end coating, the entire bottom of the bottle is covered with a film, so it has a sufficient scratch-prevention effect. However, even if it is not combined with a hot end coating, it can exhibit even greater scratch resistance. In addition, the coating film applied to the bottom of the bottle is in the form of a film with a thickness of about 10 μm and is firmly and closely attached to the glass bottle, so even if it hits a sharp protrusion on the conveyor, for example, the film will not be damaged. It is possible to fully exhibit the effect of preventing scratches.

(Example) After forming a glass bottle, when the bottle temperature is about 105°C after passing through an annealing furnace, an 8% aqueous solution of water-based polyester resin (Takamatsu oil-based product: trade name "Pess Resin 2000J") is poured into a fountain from below the mesh belt. The aqueous solution was ejected to uniformly wet the bottom of the glass bottle.The coating liquid that adhered to the bottom of the bottle became a tightly adhered, transparent, and uniform film-like coating after about 50 seconds. The thickness was approximately 10μ.

Immediately after forming, the glass bottle has almost no scratches on the bottom (and has an internal pressure resistance of 35 to 40 kg/cd), but after passing through various conveyance lines (the internal pressure strength decreases significantly due to damage to the bottom). It has been found that even glass bottles treated with a combination of conventional hot-end coating and cold-end coating with water-insoluble polyethylene wax had a decrease in internal pressure strength of about 30%. The internal pressure strength of the glass bottles (n=100) treated according to the present invention could be maintained at a minimum of 30 kg/c-, and the down rate could be suppressed to about 15%.

In addition, in the conveyor line, where the internal pressure strength of conventional bottles similar to the above was reduced by about 10%, the reduction rate of the internal pressure strength of the glass bottles treated with the present invention (n = 100 bottles) was about 1%. Yes, it was possible to maintain the internal pressure strength immediately after molding.

(Effects of the Invention) As is clear from the above description, the present invention forms a film-like coating film made of a water-soluble resin on the bottom of a glass bottle, so it is possible to eliminate the conventional combination treatment of hot-end coating and cold-end coating. Even if you don't apply it,
◎1.The present invention can be used as is for online processing by partially changing the nozzle etc. of conventional underspray coating equipment. It also has the advantage of being able to be implemented without requiring major changes to equipment.

As described above, the present invention provides a method for preventing the strength deterioration of the bottom of a glass bottle, which eliminates the conventional drawbacks, and thus makes an extremely large contribution to the industry.

Claims (1)

[Claims] (1) After applying a water-soluble resin to the bottom of the glass bottle, which is in the temperature range of 50 to 150°C after passing through a slow cooling furnace, the water-soluble resin is thermally cured using the heat retained by the bottle to form a film only on the bottom of the bottle. A method for preventing strength deterioration at the bottom of a glass bottle, characterized by forming a coating film.