WO1987006927A1 - Method for the application of a polytetrafluoroethylene coating to glass - Google Patents

Method for the application of a polytetrafluoroethylene coating to glass Download PDF

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Publication number
WO1987006927A1
WO1987006927A1 PCT/NL1987/000010 NL8700010W WO8706927A1 WO 1987006927 A1 WO1987006927 A1 WO 1987006927A1 NL 8700010 W NL8700010 W NL 8700010W WO 8706927 A1 WO8706927 A1 WO 8706927A1
Authority
WO
WIPO (PCT)
Prior art keywords
glass
ptfe
drying agent
grease
oil
Prior art date
Application number
PCT/NL1987/000010
Other languages
French (fr)
Inventor
Ignatius Cornelus Johannes Dur
Original Assignee
Rijksuniversiteit Te Utrecht
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rijksuniversiteit Te Utrecht filed Critical Rijksuniversiteit Te Utrecht
Publication of WO1987006927A1 publication Critical patent/WO1987006927A1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
    • C03C17/28—Surface treatment of glass, not in the form of fibres or filaments, by coating with organic material
    • C03C17/32—Surface treatment of glass, not in the form of fibres or filaments, by coating with organic material with synthetic or natural resins
    • C03C17/328—Polyolefins
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2218/00—Methods for coating glass
    • C03C2218/30—Aspects of methods for coating glass not covered above
    • C03C2218/31—Pre-treatment

Definitions

  • the invention relates to a method for the application of a polytetrafluoroethy lene (PTFE) coating to glass, both flat glass and glass objects such as dishes and the like being included under the term "glass".
  • PTFE polytetrafluoroethy lene
  • the method according to the invention described in the introduction is charac-terized in that a) the glass to be coated is subjected to a blasting treatment with an abrasive containing SiO 2 ; b) the blasted surface of the glass is treated with an etchant; c) the treated surface of the glass is exposed to the action of a strong grease-/oil-removing agent; d) the glass with the oil-/grease-free surface is dried with an organic drying agent; e) the glass is then freed from the drying agent in a dry, clean atmosphere; and f) PTFE is applied to the treated surface of the glass. More in particular the following may be stated in relation to the separate steps.
  • Step (a) of the method according to the invention is performed to increase and to roughen the surface of the glass.
  • an abrasive containing SiO 2 is used, the glass receiving a slightly matt surface.
  • aluminium oxide (Al 2 O 3 ) is used for blasting, the surface of the glass becomes completely matt and the strength of the glass decreases considerably because of the great damage produced at the surface.
  • Such an abrasive can therefore not be used in the method according to the invention.
  • step (b) of the method according to the invention the blasted surface of the glass is treated with an etchant in order to clean the glass surface, i.e. to detach loose particles consisting of impurities from the glass surface and to make the roughening produced by the blasting more even.
  • an HF solution in water preferably in a concentration of 5-15%, or a concentrated lye such as NaOH or KOH may be used as etchant.
  • the etched surface of the glass is treated with a grease-/oil-removing agent, advantageously with concentrated acid such as HNO 3 or H 2 SO 4 or concentrated hydrochloric acid.
  • concentrated acid such as HNO 3 or H 2 SO 4 or concentrated hydrochloric acid.
  • a further advantage of using concentrated acids of this type is the replacement of iron ions present in the glass surface by hydrogen ions from the concentrated acid. Said removal of the iron ions from the glass surface is considered useful in view of the fact that the presence thereof is apparently not conducive to the adhesion of the PTFE coating to the glass surface.
  • step (d) the glass with the oil-/grease-free surface is dried with an organic drying agent.
  • An alcohol such as methanol or ethanol or also other organic drying agents such as, advantageously, acetone may be used as the organic drying agent.
  • the viscosity of the drying agent should be low in order that such a drying agent can easily penetrate into the pores of the glass surface and can entrain the residual quantity of water present therein.
  • step (e) the glass is freed from the drying agent in a dry, clean atmosphere.
  • clean air is used for this purpose and preferably purified compressed air.
  • the use of normal compressed air is not advisable in view of the fact that in that case the risk is too great that dirt and oil particles of all types end up on the cleaned glass surface, which is not conducive to the adhesion of the PTFE coating to the glass surface.
  • the products marketed by E.I. du Pont de Nemours & Company under the tradename of "Teflon" may be used as PTFE products.
  • Teflon Pyrex glass pretreated in the manner specified above was coated by means of spraying with Teflon of the type "Bakeware 955-Z-63516".
  • the Teflon coating had a thickness of 4-5 ⁇ m and after drying for 5 minutes at 105°C, was sintered at a temperature of 300°C for
  • Pretreated Pyrex glass was coated by means of spraying with two layers of Teflon material, namely Teflon of the type “Electrical Appliancess 459-520" in a thickness of 4-5 ⁇ m and Teflon of the type “Electrical Appliancess” 456-396", also in a thickness of 4-5 ⁇ m.
  • Teflon material namely Teflon of the type "Electrical Appliancess 459-520" in a thickness of 4-5 ⁇ m and Teflon of the type “Electrical Appliancess” 456-396", also in a thickness of 4-5 ⁇ m.
  • the first Teflon layer was dried for 10 minutes at 105°C.
  • the Teflon coating was sintered at a temperature of 400°C for 15 minutes.
  • test plate obtained in accordance with this example had very good properties as regards the adhesion of the Teflon coating to the glass.
  • Example III
  • pretreated Pyrex glass was provided with two layers of Teflon.
  • the primer laer of Teflon of the type "Industrial Fep 850-314" was applied by dipping, after which the top layer of "Industrial Fep 856-204" was applied by means of spraying.
  • the primer layer was dried for 10 minutes at a temperature of 105°C, the Teflon coating being sintered at a temperature of 315°C for 10 minutes after applying the top layer of Teflon.
  • pretreated Pyrex glass was provided with a Teflon primer of the type "Industrial Fep. 850-314" by means of dipping and, after a drying time of 10 minutes at 105°C with a top layer of Teflon of the type "Topcoat 456/395" by means of spraying.
  • the Teflon coating was then sintered for 10 minutes at 430°C.
  • Symax glass pretreated in the manner specified above was coated with Teflon of the type "Bakeware 955- Z-63516" by means of spraying.
  • the Teflon coating had a thickness of 4-5 ⁇ m and, after drying for 5 minutes at 105°C, was sintered at a temperature of 300°C for 15 minutes. The adhesion of the Teflon coating to the glass was assessed as especially good.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Surface Treatment Of Glass (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Abstract

Method for the application of a polytetrafluorethylene (PTFE) coating to glass i.e. to both flat glass and glass objects such as dishes and the like; said method is characterized in that (a) the glass is subjected to a blasting treatment with an abrasive containing SiO2 preferably quartz glass; (b) the blasted surface of the glass is treated with an etchant like HF; (c) the treated surface of the glass is exposed to the action of a grease-/oil-removing agent such as HNO3 or H2SO4; (d) the glass with the oil-/grease-free surface is dried with an organic drying agent like methanol and acetone; (e) the glass is then freed from the drying agent in a dry, clean atmosphere; and (f) PTFE is applied to the treated surface of the glass.

Description

Method for the application of a polytetrafIuoroethylene coating to glass
The invention relates to a method for the application of a polytetrafluoroethy lene (PTFE) coating to glass, both flat glass and glass objects such as dishes and the like being included under the term "glass".
As is known, it has already been possible for a considerable time to apply a PTFE coating to metal objects, in, inter alia, the household field, for example frying pans and saucepans, and also baking tins, which coating has the great advantage that the cleaning of such objects can take place in a simple and rapid manner after use.
An attempt has therefore been made to provide such an inert PTFE coating on glass objects in addition to the metal objects. However, despite intensive research, this has hitherto not been successful. The reasons for this very probably lie in the fact that the surface of glass which can be described as fairly inert, is completely different from that of metal objects. The problem which occurred in coating glass in particular, was that the PTFE exhibited no, or no satisfactory, adhesion to the glass and consequently easily came off the glass. Surprisingly, the Applicant has now found a method for applying PTFE to glass which has been subjected to a special preliminary treatment.
The method according to the invention described in the introduction is charac-terized in that a) the glass to be coated is subjected to a blasting treatment with an abrasive containing SiO2; b) the blasted surface of the glass is treated with an etchant; c) the treated surface of the glass is exposed to the action of a strong grease-/oil-removing agent; d) the glass with the oil-/grease-free surface is dried with an organic drying agent; e) the glass is then freed from the drying agent in a dry, clean atmosphere; and f) PTFE is applied to the treated surface of the glass. More in particular the following may be stated in relation to the separate steps.
Step (a) of the method according to the invention is performed to increase and to roughen the surface of the glass. However, in order not to damage the glass surface too much, an abrasive containing SiO2 is used, the glass receiving a slightly matt surface. In this connection attention is drawn to the fact that if aluminium oxide (Al2O3) is used for blasting, the surface of the glass becomes completely matt and the strength of the glass decreases considerably because of the great damage produced at the surface. Such an abrasive can therefore not be used in the method according to the invention.
In view of the above, it is emphasized that when an abrasive containing SiO2, which advantageously contains as high a SiO2 content as possible, for example at least 95% SiO2, is used for blasting, the strength of the glass remains ideal. Preferably, quartz glass with a particle size of 70-110 μm is used as abrasive. In step (b) of the method according to the invention the blasted surface of the glass is treated with an etchant in order to clean the glass surface, i.e. to detach loose particles consisting of impurities from the glass surface and to make the roughening produced by the blasting more even. Advantageously, an HF solution in water, preferably in a concentration of 5-15%, or a concentrated lye such as NaOH or KOH may be used as etchant.
In the third step, (c), of the method according to the invention the etched surface of the glass is treated with a grease-/oil-removing agent, advantageously with concentrated acid such as HNO3 or H2SO4 or concentrated hydrochloric acid. This concentrated acid removes in particular the last remnants of grease and oil which are still present on the surface.
A further advantage of using concentrated acids of this type is the replacement of iron ions present in the glass surface by hydrogen ions from the concentrated acid. Said removal of the iron ions from the glass surface is considered useful in view of the fact that the presence thereof is apparently not conducive to the adhesion of the PTFE coating to the glass surface.
In step (d) the glass with the oil-/grease-free surface is dried with an organic drying agent. An alcohol such as methanol or ethanol or also other organic drying agents such as, advantageously, acetone may be used as the organic drying agent. The viscosity of the drying agent should be low in order that such a drying agent can easily penetrate into the pores of the glass surface and can entrain the residual quantity of water present therein.
In step (e) the glass is freed from the drying agent in a dry, clean atmosphere. Advantageously, clean air is used for this purpose and preferably purified compressed air. The use of normal compressed air is not advisable in view of the fact that in that case the risk is too great that dirt and oil particles of all types end up on the cleaned glass surface, which is not conducive to the adhesion of the PTFE coating to the glass surface. The products marketed by E.I. du Pont de Nemours & Company under the tradename of "Teflon" may be used as PTFE products.
The invention is explained in more detail on the basis of the examples below. For this purpose Pyrex glass has been used in Examples I-IV and Symax glass in Example V, which types of glass were subjected to the following pretreatment:
1) Blasting with "industrial" quartz glass with a particle size of 70-110 μm;
2) Rinsing with a 10% HF solution in water for 1 minute;
3) Rinsing with boiling nitric acid for 0.5 minute ; 4 ) Rinsing with methanol for 0.5 minute , and 5) Drying in the air or with well-filtered compressed air.
After the steps 1, 2 and 3 the glass was always rinsed with (double) distilled water. Example I
Pyrex glass pretreated in the manner specified above was coated by means of spraying with Teflon of the type "Bakeware 955-Z-63516". The Teflon coating had a thickness of 4-5 μm and after drying for 5 minutes at 105°C, was sintered at a temperature of 300°C for
15 minutes. The dahesion of the Teflon coating to the glass could be considered as especially good. Example II
Pretreated Pyrex glass was coated by means of spraying with two layers of Teflon material, namely Teflon of the type "Electrical Appliancess 459-520" in a thickness of 4-5 μm and Teflon of the type "Electrical Appliancess" 456-396", also in a thickness of 4-5 μm. Before the second Teflon layer was applied, the first Teflon layer was dried for 10 minutes at 105°C. After applying the second Teflon layer, the Teflon coating was sintered at a temperature of 400°C for 15 minutes.
The test plate obtained in accordance with this example had very good properties as regards the adhesion of the Teflon coating to the glass. Example III
According to this Example, pretreated Pyrex glass was provided with two layers of Teflon. The primer laer of Teflon of the type "Industrial Fep 850-314" was applied by dipping, after which the top layer of "Industrial Fep 856-204" was applied by means of spraying.
The primer layer was dried for 10 minutes at a temperature of 105°C, the Teflon coating being sintered at a temperature of 315°C for 10 minutes after applying the top layer of Teflon.
The Teflon coating exhibited a very good adhesion to the glass surface. E x a mp l e I V
In accordance with the method described in Example III, pretreated Pyrex glass was provided with a Teflon primer of the type "Industrial Fep. 850-314" by means of dipping and, after a drying time of 10 minutes at 105°C with a top layer of Teflon of the type "Topcoat 456/395" by means of spraying. The Teflon coating was then sintered for 10 minutes at 430°C.
In the case of this test plate the adhesion of the Teflon coating to the glass surface is also especially good.
Example V
Symax glass pretreated in the manner specified above was coated with Teflon of the type "Bakeware 955- Z-63516" by means of spraying. The Teflon coating had a thickness of 4-5 μm and, after drying for 5 minutes at 105°C, was sintered at a temperature of 300°C for 15 minutes. The adhesion of the Teflon coating to the glass was assessed as especially good.

Claims

C L A I M S
1. Method for the application of a polytetrafluoroethylene (PTFE) coating to glass, characterized in that a) the glass is subjected to a blasting treatment with an abrasive containing SiO2; b) the blasted surface of the glass is treated with an etchant; c) the treated surface of the glass is exposed to the action of a grease-/oil-removing agent; d) the glass with the oil-/grease-free surface is dried with an organic drying agent; e) the glass is then freed from the drying agent in a dry, clean atmosphere; and f) PTFE is applied to the treated surface of the glass.
2. Method according to Claim 1, characterized in that a material containing SiO2 with a content of at least
95% SiO2 is used as abrasive in step (a).
3. Method according to Claim 2, characterized in that quartz glass is used in step (a).
4. Method according to one or more of Claims 1-3, characterized in that an HF solution in water is used in step (b).
5. Method according to Claim 4, characterized in that a 5-15% HF solution in H2O is used in step (b).
6. Method according to one or more of Claims 1-3, characterized in that a concentrated lye is used in step (b).
7. Method according to one or more of Claims 1-6, characterized in that a concentrated acid is used in step (c) as a grease-/oil-removing agent.
8. Method according to Claim 7, characterized in that HNO3 or H2SO4 is used as concentrated acid.
9. Method according to one or more of Claims 1-8, characterized in that an alcohol such as methanol or ethanol is used in step (d) as organic drying agent.
10. Method according to one or more of Claims 1-8, characterized in that a ketone such as acetone is used in step (d) as organic drying agent.
11. Method according to one or more of Claims 1-10, characterized in that step (e) is performed by means of purified compressed air.
12. Method according to one or more of Claims 1-11, characterized in that the PTFE is applied in step (f) in at most three layers.
13. Glass objects coated with PTFE obtained by use of the method according to one or more of Claims 1-12.
PCT/NL1987/000010 1986-05-14 1987-05-12 Method for the application of a polytetrafluoroethylene coating to glass WO1987006927A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL8601225 1986-05-14
NL8601225A NL8601225A (en) 1986-05-14 1986-05-14 METHOD FOR APPLYING A POLYTETFLUOROETHENE COATING ON GLASS

Publications (1)

Publication Number Publication Date
WO1987006927A1 true WO1987006927A1 (en) 1987-11-19

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WO (1) WO1987006927A1 (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2252333A (en) * 1991-01-29 1992-08-05 Spectra Physics Scanning Syst Scanner window coated with hard material and then with lubricous coating
DE4434207A1 (en) * 1994-09-24 1996-03-28 Blue Planet Ag Solar panel
WO1997027149A1 (en) * 1996-01-29 1997-07-31 E.I. Du Pont De Nemours And Company Method of coating organic polymer onto glass surface, and organic polymer-coated glass
WO2000038845A1 (en) * 1998-12-24 2000-07-06 Sunyx Surface Nanotechnologies Gmbh Method for producing an ultraphobic surface by sand blasting
EP1213269A1 (en) * 2000-12-05 2002-06-12 Heraeus Quarzglas GmbH & Co. KG Fluororesin-coated quartz glass jig and method for producing the same
EP1371617A1 (en) * 2002-05-28 2003-12-17 Heraeus Quarzglas GmbH & Co. KG Method for producing a quartz glass tank for use in ultrasonic cleaning used for fabricating semiconductor and quartz glass tank obtainable from that method
US9630206B2 (en) 2005-05-12 2017-04-25 Innovatech, Llc Electrosurgical electrode and method of manufacturing same
US10308541B2 (en) 2014-11-13 2019-06-04 Gerresheimer Glas Gmbh Glass forming machine particle filter, a plunger unit, a blow head, a blow head support and a glass forming machine adapted to or comprising said filter

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1092473A (en) * 1965-01-23 1967-11-22 W R Midwinter Ltd Improvements relating to ceramic ware
FR2033431A5 (en) * 1969-02-24 1970-12-04 Autolubrification Aps Coating glass with fluorocarbons
FR2103479A1 (en) * 1970-08-25 1972-04-14 Jenaer Glaswerk Schott & Gen Non-stick layer on glass - applied on an intermediate layer

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1092473A (en) * 1965-01-23 1967-11-22 W R Midwinter Ltd Improvements relating to ceramic ware
FR2033431A5 (en) * 1969-02-24 1970-12-04 Autolubrification Aps Coating glass with fluorocarbons
FR2103479A1 (en) * 1970-08-25 1972-04-14 Jenaer Glaswerk Schott & Gen Non-stick layer on glass - applied on an intermediate layer

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2252333A (en) * 1991-01-29 1992-08-05 Spectra Physics Scanning Syst Scanner window coated with hard material and then with lubricous coating
GB2252333B (en) * 1991-01-29 1995-07-19 Spectra Physics Scanning Syst Improved scanner window
DE4434207A1 (en) * 1994-09-24 1996-03-28 Blue Planet Ag Solar panel
WO1997027149A1 (en) * 1996-01-29 1997-07-31 E.I. Du Pont De Nemours And Company Method of coating organic polymer onto glass surface, and organic polymer-coated glass
WO2000038845A1 (en) * 1998-12-24 2000-07-06 Sunyx Surface Nanotechnologies Gmbh Method for producing an ultraphobic surface by sand blasting
EP1213269A1 (en) * 2000-12-05 2002-06-12 Heraeus Quarzglas GmbH & Co. KG Fluororesin-coated quartz glass jig and method for producing the same
EP1371617A1 (en) * 2002-05-28 2003-12-17 Heraeus Quarzglas GmbH & Co. KG Method for producing a quartz glass tank for use in ultrasonic cleaning used for fabricating semiconductor and quartz glass tank obtainable from that method
US9630206B2 (en) 2005-05-12 2017-04-25 Innovatech, Llc Electrosurgical electrode and method of manufacturing same
US10463420B2 (en) 2005-05-12 2019-11-05 Innovatech Llc Electrosurgical electrode and method of manufacturing same
US11246645B2 (en) 2005-05-12 2022-02-15 Innovatech, Llc Electrosurgical electrode and method of manufacturing same
US10308541B2 (en) 2014-11-13 2019-06-04 Gerresheimer Glas Gmbh Glass forming machine particle filter, a plunger unit, a blow head, a blow head support and a glass forming machine adapted to or comprising said filter

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