COATING WITH THERMAL STABILITY AND ANTI-SCRATCH PROPERTIES, GLASS PRODUCT HAVING SUCH COATING, VARNISH PRODUCT FOR PRODUCING SUCH COATING AND METHOD FOR PROTECTING A GLASS SURFACE AND IN PARTICULAR A PHARMACEUTICAL PRIMARY GLASS CONTAINER

Abstract

The present invention describes a coating with lubricating and anti-scratch properties, comprising glycidoxypropyltrimethoxysilane and phenyltriethoxysilane. The present invention further describes a varnish product for producing such coating and a glass product, in particular a pharmaceutical primary glass container having such coating. Last, but not least, a method is disclosed for protecting a glass surface.

Claims

1. A coating with lubricating and anti-scratch properties, comprising glycidoxypropyltrimethoxysilane and phenyltriethoxysilane.

2. A glass product having a coating according to claim 1.

3. A pharmaceutical primary glass container having a coating according to claim 1.

4. The pharmaceutical primary glass container according to claim 3, wherein said coating has a thickness less than 50 nm.

5. A varnish product for making a coating, comprising glycidoxypropyltrimethoxysilane and phenyltriethoxysilane and a solvent.

6. The varnish product for making a coating according to claim 5, wherein said glycidoxypropyltrimethoxysilane and said phenyltriethoxysilane are each in a weight percentage between 2% and 8%.

7. The varnish product for making a coating according to claim 6, further comprising HCl (0.1N) in a weight percentage between 1% and 2%, and a photoinitiator in a weight percentage between 0.1% and 1%.

8. The varnish product for making a coating according to claim 5, wherein said solvent is either ethanol or propylene glycol methyl ether.

9. The varnish product for making a coating according to claim 5, wherein the varnish product is derived from a sol-gel varnish synthesis.

10. A method for protecting the glass surface of a glass product comprising applying a varnish product according to claim 5 to the glass surface.

Description

[0025] Specific embodiments of the production process of the coating and the application thereof according to the present invention are described below.

Configuration A

[0026] Such configuration consists of a single-layer coating.

[0027] The general formulation of the varnish product contains: [0028] glycidoxypropyltrimethoxysilane due to its mechanical properties [0029] phenyltriethoxysilane due to its thermal stability

Configuration ASynthesis of the Varnish

[0030] A varnish formulation has been developed based on a mixture between glycidoxypropyltrimethoxysilane and phenyltriethoxysilane. The implied solvent (ethanol or propylene glycol methyl ether) depends on the coating process used: [0031] For immersion coating, ethanol is used as the solvent. [0032] For spray coating, propylene glycol methyl ether is used as the solvent.

[0033] The different weight percentages in the general formulation of the varnish are listed below:

TABLE-US-00001 Compound Percentage by weight Glycidoxypropyltrimethoxysilane 2-8.00% Phenyltriethoxysilane 2-8.00% Solvent (propylene glycol methyl ether or 60-96.0% ethanol according to the process) HCl (0.1N) 1-2% Photoinitiator 0.1-1%

[0034] Glycidoxypropyltrimethoxysilane and phenyltriethoxysilane are hydrolyzed separately with hydrochloric acid (10%) in stoichiometric proportion for at least 1 hour under magnetic agitation at ambient temperature.

[0035] Hydrolyzed glycidoxypropyltrimethoxysilane and phenyltriethoxysilane are then mixed together and the solvent is added. The solution is agitated for a number of minutes. A photoinitiator, for example Irgacure PAG 290, is then added to the formulation. Such photoinitiator guarantees the cross-linking of the organic portions under UV light.

[0036] At this point the varnish formulation is ready to use.

[0037] The specific varnish formulations and their characteristics are listed below.

Specific Varnish Formulation A1 (Intended Use for Immersion Coating)

[0038]

TABLE-US-00002 Precursor role (3-Glycidyloxypropyl)trimethoxysilane Glymo Precursor .sup.4% Phenyltriethoxysilane Precursor .sup.4% Hydrochloric acid (0.1N) activator 1.9% PAG 290 UV Photoinitiator 0.1% Ethanol Solvent 90%

100 g Synthesis of Varnish Formulation A1.

[0039] Introduction of 4 g of Glymo in a first glass beaker and addition of 0.9 g of hydrochloric acid.

[0040] In a second glass beaker, addition of 4 g of phenyltriethoxysilane and 1 g of hydrochloric acid.

[0041] Mixture of the beakers for 1 hour under magnetic agitation (250-300 rpm).

[0042] Mixture of the beaker with Glymo with one of phenyltriethoxysilane until homogenization (1 minute at 250-300 rpm).

[0043] Addition of 90 g of ethanol and 0.1 g of PAG 90. The solution is left for 10 minutes under magnetic agitation (250-300 rpm).

[0044] As mentioned, the varnish is then coated onto the glass substrate through immersion coating and then hardened with UV (60 secondsmercury lamp).

Properties of the Varnish Formulation A1 (Liquid Phase)

[0045]

TABLE-US-00003 Density 0.811 Solid content 0.95% Viscosity 1.5 cP Colour/appearance Transparent/colourless Surface tension (mN/m) 21.3 pH 2.5

Specific Varnish Formulation A2 (Intended Use for Spray Coating)

[0046]

TABLE-US-00004 Precursor role (3-Glycidyloxypropyl)trimethoxysilane Glymo Precursor .sup.4% Phenyltriethoxysilane Precursor .sup.4% Hydrochloric acid (0.1N) Activator 1.9% PAG 290 UV Photoinitiator 0.1% Propylene glycol monomethyl ether acetate Solvent 90% Dowanol

100 g Synthesis of Varnish Formulation A2.

[0047] Introduction of 4 g of Glymo in a first glass beaker and addition of 0.9 g of hydrochloric acid.

[0048] In a second glass beaker, addition of 4 g of phenyltriethoxysilane and 1 g of hydrochloric acid.

[0049] Mixture of beakers for 1 hour under magnetic agitation (250-300 rpm).

[0050] Mixture of the beaker with Glymo with one of phenyltriethoxysilane until homogenization (about 1 minute at 250-300 rpm).

[0051] Addition of 90 g of Dowanol and 0.1 g of PAG 90. The GFD solution is left for 10 minutes under magnetic agitation (250-300 rpm).

[0052] As mentioned, the varnish is then coated onto the glass substrate through spray coating and then hardened with UV (60 secondsmercury lamp).

Properties of the Varnish Formulation A2 (Liquid Phase)

[0053]

TABLE-US-00005 Density 0.973 Dry matter content 0.62% Viscosity 1.5 cP Colour/appearance Transparent/slightly yellow Surface tension (mN/m) 25.2 pH 1.6

Coating Process

[0054] The process described below refers to pharmaceutical primary glass containers only by way of example, since the application may, as mentioned, also include other types of substrates.

Cleaning/Degreasing

[0055] For glass bottles, the pretreatment process is the same for every configuration.

[0056] Before being coated, each bottle is degreased with fabric and ethanol. Subsequently, the bottles are treated by atmospheric plasma with air for 30 s. In a different embodiment, a low pressure plasma treatment with a mixture of N.sub.2/H.sub.2 gas may be performed.

[0057] The bottles are coated following this treatment.

Coating

[0058] In configuration A with propylene glycol methyl ether, the coating process is performed through spray coating. In that case, the spraying is performed for 0.4 s at a pressure at the nozzle of 50 psi. While the varnish is sprayed, the bottle rotates at a speed of 480 rpm.

[0059] In configuration A with ethanol, the coating process is performed through immersion coating. In that case the extraction speed is 50 mm/min.

Hardening

[0060] After the deposition process, the coatings must be hardened under UV light with the following wavelengths, UVA (320-390 nm), UVB (280-320 nm), UVC (250-260 nm), UVV (395-445 nm) for 3 min.

[0061] It is to be understood that changes and variations that are not beyond the scope of the invention as defined in the appended claims may be made to the coating and to the related production method described and illustrated herein.