KR20060007896A - Glass forming lubricant - Google Patents

Abstract

The present invention is a glass mold release agent that is applied to a glass mold for molding so that the completed glass can be easily released (or demolded) without sticking to the mold, to minimize the surface defect of the glass molded article, various methods The purpose is to provide a new low-viscosity release agent that can be easily applied to the mold.

The release agent according to the present invention for this purpose is characterized in that the inorganic oxide is dispersed in the form of a slurry in water or an alcoholic solvent, wherein the inorganic oxide is magnesium (Mg), aluminum (Al), silicon (Si), Titanium oxide (Ti), or a mixture of two or more of these inorganic oxides.

Glass Molding, Inorganic Oxide, Release Agent, Mold

Description

Release Agent for Glass Molding {Glass Forming Lubricant}

The present invention relates to a release agent for glass molding, and more particularly to a new low-viscosity release agent for glass molding to minimize the surface defect of the glass molded article, which can be easily applied to the mold in a variety of ways.

In general, in the case of manufacturing a glass molded product using a mold, a mold release agent for glass molding (hereinafter, 'release agent') is used so that the molded glass can be easily released (or demolded) without sticking to the mold. In the case of processing press glass or blow molding by pouring the molten glass from the melting furnace into a mold, or processing automotive glass heated in the form of glass plate, furthermore, to manufacture a molded article having a somewhat complicated shape as a plate shape. In this case, the use of a suitable release agent is an important problem.

Conventionally, as such a release agent, a method of chromium coating the surface of the mold or a mold release agent in the form of a solid wax or a solution diluted in machine oil has been applied to the mold by hand. Heavy metal chromium is used for the environment and human body. Can cause serious problems, and its use is strictly regulated. Graphite, which is included in most release agents as release agents or lubricants, makes the release agent itself black, making it difficult to keep the working environment clean. There was a problem with the glass molded product produced.

In addition, the conventional mold release agent has a problem of causing a defect on the surface of the glass molded article or leaving oil traces or wrinkles on the glass molded article when the release agent applied by hand is not partly applied to the mold surface due to its high viscosity.

The present invention has been proposed to solve this problem, and aims to provide a low release new release agent that can be easily applied to a mold by various methods to minimize the surface defect of the glass molded product due to the graphite contained in the release agent. .

Release agent according to the present invention for achieving the above object, characterized in that consisting of a solution of inorganic oxides dispersed in a slurry form in water or an organic solvent.

Inorganic oxides have the main function of preventing adhesion between glass and mold, but they should be excellent in solvent and dispersibility to evenly coat the glass, and low hardness is important for minimizing wear of mold. Choosing less wear. In this regard, Al ₂ O ₃ or SiO ₂ can be used as a release agent in spite of its high hardness, and magnesium oxide can be used as a releasing agent. Due to its excellent low hardness, it is also suitable as a release agent. Titanium oxide system has the intermediate properties of aluminum oxide and magnesium oxide mentioned above.

Therefore, the inorganic oxide usable as the release agent is preferably an oxide of any one of magnesium (Mg), aluminum (Al), silicon (Si), titanium (Ti) or a mixture of two or more of these inorganic oxides, and the solvent is water or alcohol It is preferable to use a system solvent. In particular, the alcohol solvent is not only excellent in the dispersibility of the above-described inorganic oxide, but also easily dried in the drying process after application to the glass, and has little effect on the glass molded article. Such alcohol solvents include ethanol, methanol, and the like, and an aqueous solution diluted in water is used. The alcohol solvent in the present description shall include not only the pure alcohol solvent itself but also an aqueous solution diluted in water.

In addition, it is preferable that nonionic surface active agents (Nonionic Surface Active Agents) are added to the solution in which the inorganic oxides are dispersed, so that the inorganic oxides are dispersed in the solvent (also prevent precipitation) and serve as a binder when the release agent is applied.

In this case, the nonionic surfactant to be added is added in a minimum amount so that the inorganic oxide can be dispersed in the alcohol solvent and applied to the mold (or glass), and the temperature at which the glass is processed (about 700 to 750 ° C). It is desirable to select a component that does not oxidize with the air and leave no traces. Preferred examples include nonylphenylether surfactants.

Such a release agent does not contain graphite and thus does not cause surface defects of the glass molded article due to graphite. The mold release agent may be directly applied to a mold or glass to be molded or molded by various methods, and may be applied directly to a glass rather than a mold. The high affinity prevents glass from adhering to the metal during glass molding.

Coating methods include dipping, spraying, and printing, and when the release agent is directly applied to a mold, the coating amount is made to be the minimum amount (or optimum amount) to generate steam at the glass forming temperature. Molding defects caused by the mold is not generated, and when the release agent is directly applied to the glass, the release agent is applied and dried in advance before being heated to the glass forming temperature. After molding is completed, it is washed in water to remove the release agent remaining in the glass.

Hereinafter, look at a specific embodiment of the release agent according to the present invention.

Example 1

100 g of finely ground Al ₂ O ₃ is placed in 1 ° C. of water and dispersed in a slurry state. At this time, stirring was continued to prevent the formation of precipitates, and 0.5 g of polyoxyethylene nonylphenyl ether was optionally added as a nonionic surfactant based on nonylphenylether. After sufficiently stirring and spraying the slurryed release agent directly to the glass plate at room temperature, dried at 150 ℃ for 10 minutes, and placed on a glass molding machine (molding) to raise the temperature of the glass molding machine to 750 ℃ to form a glass.

Next, the molded glass was cooled and the glass was taken out from the glass molding machine, and the inorganic oxide applied to the taken out glass was washed with running water for 5 minutes and then dried. At this time, ultrasonic waves were used to completely remove the inorganic oxides. The glass plate used was soda-lime glass, 5 cm wide, 5 cm long, and 1.5 mm thick.

As a result of the experiment, the release agent using Al ₂ O ₃ retained the coating state on the glass as it was, regardless of whether a nonionic surfactant was added during stirring, and the release agent did not adhere to the mold even after molding. The release agent was removed from. In addition, the molding state of the glass molded article was good.

Example 2

The experiment was carried out under the same conditions as in Example 1, but MgO was used as the inorganic oxide, and the washing period was 10 minutes.

As a result of the experiment, as in Example 1, the application state on the glass was maintained as it was, regardless of whether the nonionic surfactant was added, and the release agent did not remain on the mold even after molding, and the release agent was removed from the glass after washing. The molding state of the glass molded article was good.

Example 3

The experiment was carried out under the same conditions as in Example 1, except that TiO ₂ was used as the inorganic oxide, and the washing time was 7 minutes.

As a result, when the nonionic surfactant was not added, the coating state on the glass was partially damaged and the mold was contaminated. When the nonionic surfactant was added, the coating state on the glass was maintained as it is. Of course, in either case, the inorganic oxide was completely removed from the glass after washing, and the shaping state of the glass was also good.

Example 4

The experiment was carried out under the same conditions as in Example 1, except that SiO ₂ was used as the inorganic oxide, and the washing time was 4 minutes.

Experimental results were similar to those of Example 3.

Examples 5-7

The experiment was carried out under the same conditions as in Example 1, but as the inorganic oxide, a mixture of SiO ₂ and TiO ₂ in a weight ratio of 1: 1 was used, and the washing period was 5 minutes each. Similarly, experiments were also conducted for the mixture of MgO and Al ₂ O ₃ (1: 1) and the mixture of MgO and SiO ₂ (1: 1), and the washing time was 6 minutes and 6 minutes, respectively.

Experimental results showed that each release agent remained intact on the glass regardless of whether a nonionic surfactant was added or not, and the mold release agent did not remain on the mold after molding, and the release agent was removed from the glass after cleaning. The molding state of was good.

Comparative example

As a comparative example with the previous example, when the glass was molded without applying a release agent made of an inorganic oxide to the glass, the glass was broken without sticking to the mold.

In addition, when the non-ionic surfactant is added, the release agent containing graphite as in the conventional case is not only stained with the black color peculiar to the release agent and contaminated the mold and glass, and even when the non-ionic surfactant is added, the stain is completely washed. It wasn't. In addition, the washing time took 20 minutes or more, and partial breakage occurred in the glass after molding.

Such a result is shown as a table | surface as follows.

Experiment Kinds Application of release agent to glass (depending on addition of nonionic surfactant) Cleaning time Glass molding radish U Comparative example Graphite Mold / Euro Salt Smudge fine chuck 20 minutes or more Partial glass breakage Example 1 Al ₂ O ₃ Maintain glass coating Maintain glass coating 5 minutes Good Example 3 MgO Maintain glass coating Maintain glass coating 10 minutes Good Example 2 TiO ₂ Partial mold contamination Maintain glass coating 7 minutes Good Example 4 SiO ₂ Partial mold contamination Maintain glass coating 4 minutes Good Example 5 SiO ₂ / TiO ₂ Maintain glass coating Maintain glass coating 5 minutes Good Example 6 MgO / Al ₂ O ₃ Maintain glass coating Maintain glass coating 6 minutes Good Example 7 MgO / SiO ₂ Maintain glass coating Maintain glass coating 6 minutes Good

As a result of Example 1 to Example 4, the coating state on the glass and the forming state of the glass were better than those of graphite, and in particular, the application of the inorganic oxide was good and the molding was poor when the nonionic surfactant was used. Rarely occurred.

In Examples 5 to 7, the inorganic oxides were mixed 1: 1 by weight, but the results were not significantly different. However, when the SiO ₂ / TiO ₂ mixture is used, the cleaning time was slightly shortened.

According to the inorganic mold release agent composed as described above, the adhesion of the mold and the glass is prevented while the glass is molded, thereby minimizing the defects during the glass molding.

In addition, since the release agent does not contain graphite, surface defects exhibited in conventional glass molded articles due to graphite are prevented.

In addition, the release agent may be easily applied by various methods such as dipping, spraying, and printing due to its low viscosity, and in particular, may be directly applied to glass as well as to a mold. The release agent applied to the glass or mold can be completely removed from the glass by washing to improve the product yield and quality of the glass molded article.

Claims (3)

In the mold release agent for glass molding applied to the mold or the glass to be molded in order to prevent the adhesion of the mold and glass, Release agent for glass molding, characterized in that consisting of a solution in which the inorganic oxide is dispersed in a slurry form in water or alcohol solvent. The method of claim 1, The inorganic oxide is a mold release agent for glass molding, characterized in that the oxide of any one of magnesium (Mg), aluminum (Al), silicon (Si), titanium (Ti) or a mixture of two or more of these inorganic oxides. The method of claim 1, A nonionic surfactant is added to the solution in which the said inorganic oxide is disperse | distributed, The mold release agent for glass molding characterized by the above-mentioned.