WO1997031034A1 - Method for reducing crazing in a plastics material - Google Patents
Method for reducing crazing in a plastics material Download PDFInfo
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- WO1997031034A1 WO1997031034A1 PCT/AU1997/000101 AU9700101W WO9731034A1 WO 1997031034 A1 WO1997031034 A1 WO 1997031034A1 AU 9700101 W AU9700101 W AU 9700101W WO 9731034 A1 WO9731034 A1 WO 9731034A1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
- C08J7/12—Chemical modification
- C08J7/123—Treatment by wave energy or particle radiation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/46—Polymerisation initiated by wave energy or particle radiation
- C08F2/52—Polymerisation initiated by wave energy or particle radiation by electric discharge, e.g. voltolisation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
- C08J7/12—Chemical modification
- C08J7/16—Chemical modification with polymerisable compounds
- C08J7/18—Chemical modification with polymerisable compounds using wave energy or particle radiation
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D4/00—Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
Definitions
- the present invention relates to a method for reducing crazing in a plastics material, in particular a transparent plastics material.
- Crazing is a phenomenon where microvoids form in the body of the materials. These microvoids may not cause a significant deterioration in mechanical strength of the article, but they do reflect/refract light and decrease the clarity of the article. Ultimately, crazing decreases the strength of the article and can lead to failure.
- the cause of crazing is unknown and may be manifold. It is thought that one cause is the diffusion of small molecules such as water or surfactants into the material which decreases the attractive forces between polymer chains and allows movement of molecules under internal or external stress thus forming microvoids.
- a method for reducing crazing in a plastics material which comprises the steps of:
- the method of the present invention may be used to reduce crazing in a wide variety of plastics materials, such as, for example, acrylics, styrenes, polycarbonates, polyesters or polyurethanes
- plastics material may be an article which is preferably in the form of a laminate or sheet
- transparent plastics material where visual clarity is important
- transparent materials include acrylic or polycarbonate sheets as used for the windows of transport vehicles such as aircraft, boats, trains and motor vehicles, signs or for architectural uses such as in roofing, glazing sheets and light fittings
- the material may be cleaned in step (1) by any method which leaves the surface substantially free of any contamination capable of interfering with the adhesion of the plasma polymer coating
- a preferred method of cleaning the surface is to subject the material to a low pressure plasma of an inert gas such as argon, neon, or nitrogen
- Another preferred method of cleaning the surface involves subjecting the material to a low pressure plasma of an oxidising gas such as air or oxygen Water vapour is also a suitable oxidising gas for this purpose
- the monomer used in step (2) may be any saturated or unsaturated organic compound capable of producing a coating of a substantially non-oxidising polymer containing organic groups
- Suitable saturated monomers include siloxanes, fluorinated compounds, lower hydrocarbons, lower alcohols, lower alkylamines and mixtures thereof
- lower refers to monomers containing 1 to 12 carbon atoms
- Suitable unsaturated monomers include acrylic esters, methacry c esters, vinyl esters, vinyl aromatics, unsaturated or poiyunsaturated hydrocarbons and mixtures thereof
- Plasma polymers from some of these monomer classes typically undergo extensive oxidation on aging (Gegennbach et al, J Polymer Sci, Part A Polymer Chemistry, 32, 1399-1414 (1994); Jacobnbach et al, Surface Interface Analysis, in press 1996). In those cases it is necessary to carefully adjust the plasma deposition parameters until minimal oxidation following ageing in the air is obtained. While substantial oxidation can occur in plasma polymers without affecting their structural integrity, minimal oxidation lessens the danger of adverse changes to the surface or mechanical properties of a plasma polymer as it ages. As used herein, the term "substantially non-oxidising polymer" refers to materials which show such minimal oxidation.
- the substantially non-oxidising polymer coating is preferably hydrophobic.
- Siloxanes or perfluorinated compounds are particularly suitable monomers for producing hydrophobic coatings provided that the resulting polymer contains some organic groups. Examples of such monomers include hexamethyldisiloxane, vinyltrimethoxysilane, perfluorocyclohexane and tetrafluoroethylene.
- hydrophilic coating may be more suitable in which case monomers such as alcohols or alkylamines may be used.
- monomers such as alcohols or alkylamines
- Preferred examples of such monomers include methanol, ethanol and the various isomers of propanol or butanol.
- the plasma polymer coatings produced by the method of this invention are usually highly crosslinked and hence stable. They may also be abrasion resistant.
- the present invention achieves this by ensuring that the plasma polymer coating applied in step (2) is thin and adheres well to the material so that it moves with the material without itself cracking or crazing. It is preferred that the plasma polymer coating has a thickness of about 2 to about 5 500 nm, more preferably about 5 to about 50 nm.
- the method of the present invention may be carried out in any suitable apparatus for performing plasma polymerisation such as that described in AU 654131.
- AU 654131 describes a process for plasma coating polymeric materials in a vapour of an amide monomer so as to provide a coating suitable for the growth of cells on biomedical implants to be administered into the human body.
- low pressure plasma polymerisation is employed in which the 5 pressure is about 0.5 to about 1.0 torr.
- the present invention also provides a craze resistant article comprising a plastics material having a thin coating of a substantially non-oxidizing plasma polymer containing organic groups
- Test strips of 35 cm x 3 cm were cut from a 3 mm thick acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues and repeated twice further with fresh tissues. The final preparation of the surface was achieved by treatment in an air plasma under the following conditions:
- the coating was applied to the air plasma cleaned sample by exposure to a plasma in hexamethyl disiloxane vapour under the following conditions:
- Test strips prepared according to Example 1 were tested for susceptibility to crazing using a modification of the cantilever test method of Burchill, Mathys and Stacewicz (J. Materials Science 22, 483-487 (1987)) which is a modification of the standard test method ANSI/ ASTM F484-77 "Stress crazing of acrylic plastics in contact with liquid or semi-liquid compounds".
- the samples were 35 cm long.
- a weight of 1 kg was suspended from the unsupported end of the test strip. The load was applied for 10 mins before placing the test fluid (iso-propanol) on the tensile surface which was kept wet until examination for crazing (at least a further 20 mins). Uncoated control strips cut from the same sheet crazed within 20 mins. However, the strips prepared in Example 1 did not craze after 6 hrs when the test was halted.
- Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an air plasma under the following conditions:
- the coating was applied to the plasma-cleaned sample by exposure to a plasma in n-heptylamine vapour under the following conditions:
- Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet.
- the coating was applied to the plasma-cleaned sample by exposure to a plasma in n-heptylamine vapour under the following conditions:
- Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an air plasma under the following conditions:
- the coating was applied to the plasma-cleaned sample by exposure to a plasma in n-hexane vapour under the following conditions: 0.11 Torr pressure 200 kHz frequency 20 Watt load power 120 second duration.
- Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an argon plasma under the following conditions:
- the coating was applied to the plasma-cleaned sample by exposure to a plasma in n-hexane vapour under the following conditions:
- Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues Final preparation of the surface was achieved by treatment in an air plasma under the following conditions
- the coating was applied to the plasma-cleaned sample by exposure to a plasma in methanol vapour under the following conditions
- Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an air plasma under the following conditions:
- the coating was applied to the plasma-cleaned sample by exposure to a plasma in perfluorodimethylcyclohexane vapour under the following conditions:
- Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an air plasma under the following conditions.
- the coating was applied to the plasma-cleaned sample by exposure to a plasma in methyl methacrylate vapour under the following conditions:
- Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an air plasma under the following conditions:
- the coating was applied to the plasma-cleaned sample by exposure to a plasma in n-butyl methacrylate vapour under the following conditions:
- Test strips prepared according to Examples 3 - 10 were tested for susceptibility to crazing using a modification of the cantilever test method of Example 2.
- the samples were 35 cm long and a weight of 1 kg was suspended from the unsupported end of the test strip. The load was applied and the test fluid (isopropanol) applied immediately to the tensile surface which was kept wet and under observation until crazing occurred.
- test fluid isopropanol
Abstract
A method for reducing crazing in a plastics material characterised in that it comprises the steps of: (1) cleaning the surface of the material; and (2) exposing the cleaned surface to plasma of a monomer vapour so as to produce a substantially non-oxidising plasma polymer coating on the surface.
Description
METHOD FOR REDUCING CRAZING IN A PLASTICS MATERIAL
The present invention relates to a method for reducing crazing in a plastics material, in particular a transparent plastics material.
When transparent plastics materials are used for windows, roofing, signs or light fittings maintenance of their original optical clarity is important. Unfortunately, under the influence of environmental factors such as light, heat and moisture many plastics materials suffer from crazing. Crazing is a phenomenon where microvoids form in the body of the materials. These microvoids may not cause a significant deterioration in mechanical strength of the article, but they do reflect/refract light and decrease the clarity of the article. Ultimately, crazing decreases the strength of the article and can lead to failure.
As crazing is a visually obvious deterioration in the material, it gives an impression of poor quality or lack of maintenance which is particularly objectionable in applications where visual clarity is desired. Such applications include the windows of transport vehicles, roofing sheets, light fittings or signs. Many signs are made of transparent materials with the graphic material applied to the underside to be viewed through the material. Crazing in vehicle windows interferes with the vision of the occupants decreasing their enjoyment of the journey and may even pose a real safety hazard. Crazing is particularly objectionable in aircraft windows and frequently causes the replacement, at a great expense, of windows which are otherwise sound and serviceable. As a consequence of the crazing problem, the use of glass windows is being considered for aircraft despite the weight penalty that this would impose.
The cause of crazing is unknown and may be manifold. It is thought that one cause is the diffusion of small molecules such as water or surfactants into the material which decreases the attractive forces between polymer chains and allows movement of molecules under internal or external stress thus forming microvoids.
According to the present invention there is provided a method for reducing crazing in a plastics material which comprises the steps of:
(1) cleaning the surface of the material; and
(2) exposing the cleaned surface to plasma of a monomer vapour so as to produce a substantially non-oxidising plasma polymer coating on the surface
The method of the present invention may be used to reduce crazing in a wide variety of plastics materials, such as, for example, acrylics, styrenes, polycarbonates, polyesters or polyurethanes The plastics material may be an article which is preferably in the form of a laminate or sheet The method will have particular value when applied to transparent plastics material where visual clarity is important Examples of transparent materials include acrylic or polycarbonate sheets as used for the windows of transport vehicles such as aircraft, boats, trains and motor vehicles, signs or for architectural uses such as in roofing, glazing sheets and light fittings
The material may be cleaned in step (1) by any method which leaves the surface substantially free of any contamination capable of interfering with the adhesion of the plasma polymer coating A preferred method of cleaning the surface is to subject the material to a low pressure plasma of an inert gas such as argon, neon, or nitrogen Another preferred method of cleaning the surface involves subjecting the material to a low pressure plasma of an oxidising gas such as air or oxygen Water vapour is also a suitable oxidising gas for this purpose These cleaning methods may be advantageously carried out in the same apparatus which is used in step (2) of the method
The monomer used in step (2) may be any saturated or unsaturated organic compound capable of producing a coating of a substantially non-oxidising polymer containing organic groups
Suitable saturated monomers include siloxanes, fluorinated compounds, lower hydrocarbons, lower alcohols, lower alkylamines and mixtures thereof The term "lower" as used herein refers to monomers containing 1 to 12 carbon atoms
Suitable unsaturated monomers include acrylic esters, methacry c esters, vinyl esters, vinyl aromatics, unsaturated or poiyunsaturated hydrocarbons and mixtures thereof Examples of these monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyi acrylate,
methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, vinyl acetate, styrene, p-chloromethylstyrene, 2-vinylpyridine, 4-vinylpyridine, N-vinylpyrrolidone, vinyl halides of the formula C ^CHX wherein X in Cl or F, vinylidene halides of the formula CH2=CX2 wherein X is independently Cl or F, vinyl ethers of the formula
wherein R is alkyl, and allyl derivatives such as allyl ethers, allyl carbonates or diallyl carbonates.
Plasma polymers from some of these monomer classes typically undergo extensive oxidation on aging (Gegennbach et al, J Polymer Sci, Part A Polymer Chemistry, 32, 1399-1414 (1994); Gegennbach et al, Surface Interface Analysis, in press 1996). In those cases it is necessary to carefully adjust the plasma deposition parameters until minimal oxidation following ageing in the air is obtained. While substantial oxidation can occur in plasma polymers without affecting their structural integrity, minimal oxidation lessens the danger of adverse changes to the surface or mechanical properties of a plasma polymer as it ages. As used herein, the term "substantially non-oxidising polymer" refers to materials which show such minimal oxidation.
It has been found that for windows made from acrylic polymers such as those used in aircraft, the substantially non-oxidising polymer coating is preferably hydrophobic. Siloxanes or perfluorinated compounds are particularly suitable monomers for producing hydrophobic coatings provided that the resulting polymer contains some organic groups. Examples of such monomers include hexamethyldisiloxane, vinyltrimethoxysilane, perfluorocyclohexane and tetrafluoroethylene.
For plastics materials where the crazing is caused by exposure to hydrophobic molecules such as petroleum products, a hydrophilic coating may be more suitable in which case monomers such as alcohols or alkylamines may be used. Preferred examples of such monomers include methanol, ethanol and the various isomers of propanol or butanol.
The plasma polymer coatings produced by the method of this invention are usually highly crosslinked and hence stable. They may also be abrasion resistant.
Many of the materials to which the method of the present invention can be applied are subject to varying stresses in service and move or flex slightly as a consequence. Accordingly,
there is a need to match the mechanical compliance of the coating with that of the material. The present invention achieves this by ensuring that the plasma polymer coating applied in step (2) is thin and adheres well to the material so that it moves with the material without itself cracking or crazing. It is preferred that the plasma polymer coating has a thickness of about 2 to about 5 500 nm, more preferably about 5 to about 50 nm.
The prior art methods produce thicker coatings which are unable to follow the movement of the material and crack and/or delaminate.
0 The method of the present invention may be carried out in any suitable apparatus for performing plasma polymerisation such as that described in AU 654131. AU 654131 describes a process for plasma coating polymeric materials in a vapour of an amide monomer so as to provide a coating suitable for the growth of cells on biomedical implants to be administered into the human body. Preferably, low pressure plasma polymerisation is employed in which the 5 pressure is about 0.5 to about 1.0 torr.
The present invention also provides a craze resistant article comprising a plastics material having a thin coating of a substantially non-oxidizing plasma polymer containing organic groups
0 This invention is further explained and illustrated in the following non-limiting examples
Example 1 - Coating of acrylic plastic sheet
Test strips of 35 cm x 3 cm were cut from a 3 mm thick acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues and repeated twice further with fresh tissues. The final preparation of the surface was achieved by treatment in an air plasma under the following conditions:
0.55 Torr pressure of air 225 kHz frequency 10 Watt load power
60 sees duration.
The coating was applied to the air plasma cleaned sample by exposure to a plasma in hexamethyl disiloxane vapour under the following conditions:
0.11 Torr pressure 225 kHz frequency 50 Watt load power 240 sees duration.
A strong adherent coating of plasma polymer was formed.
Example 2 - Evaluation of effect of coatings on craze resistance
Test strips prepared according to Example 1 were tested for susceptibility to crazing using a modification of the cantilever test method of Burchill, Mathys and Stacewicz (J. Materials Science 22, 483-487 (1987)) which is a modification of the standard test method ANSI/ ASTM F484-77 "Stress crazing of acrylic plastics in contact with liquid or semi-liquid compounds". The samples were 35 cm long. A weight of 1 kg was suspended from the unsupported end of the test strip. The load was applied for 10 mins before placing the test fluid (iso-propanol) on the tensile surface which was kept wet until examination for crazing (at least a further 20 mins).
Uncoated control strips cut from the same sheet crazed within 20 mins. However, the strips prepared in Example 1 did not craze after 6 hrs when the test was halted.
EXAMPLE 3 - Coating of Commercial Acrylic Sheet with n-heptylamine polymer after air plasma cleaning
Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an air plasma under the following conditions:
0.50 Torr pressure 200 kHz frequency 10 Watt load power 60 second duration.
The coating was applied to the plasma-cleaned sample by exposure to a plasma in n-heptylamine vapour under the following conditions:
0.40 Torr pressure
200 kHz frequency 10 Watt load power 180 second duration.
A coating of plasma polymer ca 120 nm thick formed.
EXAMPLE 4 - Coating of Commercial Acrylic Sheet with n-heptylamine polymer after argon plasma cleaning
Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet.
Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an
argon plasma under the following conditions:
0.50 Torr pressure 200 kHz frequency 10 Watt load power
60 second duration.
The coating was applied to the plasma-cleaned sample by exposure to a plasma in n-heptylamine vapour under the following conditions:
0.40 Torr pressure 200 kHz frequency 20 Watt load power 180 second duration.
A coating of plasma polymer ca 110 nm thick formed.
EXAMPLE 5 - Coating of Commercial Acrylic Sheet with n-hexane polymer after air plasma cleaning
Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an air plasma under the following conditions:
0.50 Torr pressure 200 kHz frequency 10 Watt load power 60 second duration.
The coating was applied to the plasma-cleaned sample by exposure to a plasma in n-hexane vapour under the following conditions:
0.11 Torr pressure 200 kHz frequency 20 Watt load power 120 second duration.
A coating of plasma polymer ca 140 nm thick formed.
EXAMPLE 6 Coating of commercial acrylic sheet with n-hexane polymer after argon plasma cleaning
Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an argon plasma under the following conditions:
0.50 Torr pressure 200 kHz frequency 10 Watt load power 60 second duration.
The coating was applied to the plasma-cleaned sample by exposure to a plasma in n-hexane vapour under the following conditions:
0.40 Torr pressure 200 kHz frequency
20 Watt load power 120 second duration.
A coating of plasma polymer ca 130 nm thick formed.
EXAMPLE 7 - Coating of commercial acrylic sheet with methanol polymer after air plasma cleaning
Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues Final preparation of the surface was achieved by treatment in an air plasma under the following conditions
0 50 Torr pressure 200 kHz frequency
10 Watt load power 60 second duration
The coating was applied to the plasma-cleaned sample by exposure to a plasma in methanol vapour under the following conditions
0 60 Torr pressure 200 kHz frequency 20 Watt load power 600 second duration
A coating of plasma polymer ca 51 nm thick formed
EXAMPLE 8 Coating of commercial acrylic sheet with perfluorodimethylcyclohexane polymer after air plasma cleaning
Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an air plasma under the following conditions:
0.50 Torr pressure 200 kHz frequency
10 Watt load power 60 second duration.
The coating was applied to the plasma-cleaned sample by exposure to a plasma in perfluorodimethylcyclohexane vapour under the following conditions:
0.2 Torr pressure 200 kHz frequency 5 Watt load power 180 second duration.
A coating of plasma polymer ca 120 nm thick formed.
EXAMPLE 9 - Coating of commercial acrylic sheet with methyl methacrylate polymer after air plasma cleaning
Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an air plasma under the following conditions.
0.50 Torr pressure
200 kHz frequency 10 Watt load power 60 second duration.
The coating was applied to the plasma-cleaned sample by exposure to a plasma in methyl methacrylate vapour under the following conditions:
0.5 Torr pressure 200 kHz frequency 10 Watt load power
60 second duration.
A coating of plasma polymer ca 210 nm thick formed.
EXAMPLE 10 - Coating of commercial acrylic sheet with n-butyl methacrylate polymer after air plasma cleaning
Test strips of 35 cm x 3 cm were cut from 3 mm thick commercial cast acrylic sheet. Each strip was cleaned by wiping with toluene-soaked, lint-free tissues, and wiping repeated twice more with fresh tissues. Final preparation of the surface was achieved by treatment in an air plasma under the following conditions:
0.50 Torr pressure 200 kHz frequency
10 Watt load power 60 second duration.
The coating was applied to the plasma-cleaned sample by exposure to a plasma in n-butyl methacrylate vapour under the following conditions:
0.5 Torr pressure
200 kHz frequency 5 Watt load power 120 second duration.
A coating of plasma polymer ca 125 nm thick formed.
EXAMPLE 11 - Evaluation of effect of coatings on craze resistance to polar materials.
Test strips prepared according to Examples 3 - 10 were tested for susceptibility to crazing using a modification of the cantilever test method of Example 2. The samples were 35 cm long and a weight of 1 kg was suspended from the unsupported end of the test strip. The load was applied and the test fluid (isopropanol) applied immediately to the tensile surface which was kept wet and under observation until crazing occurred.
Although all test strips eventually crazed, all treated strips lasted at least ten times longer than uncoated control strips.
These results demonstrate that the process of the invention enhances the craze resistance of commercial acrylic sheet such as that used for glazing or signs as well as the stretched acrylic sheet used for aircraft windows.
Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.
Claims
CLAΓMS
1 A method for reducing crazing in a plastics material characterised in that it comprises the steps of (1) cleaning the surface of the material; and
(2) exposing the cleaned surface to plasma of a monomer vapour so as to produce a substantially non-oxidising plasma polymer coating on the surface
2. A method as claimed in Claim 1, characterised in that the monomer in step (2) is a saturated or unsaturated organic compound capable of producing a coating of a substantially non-oxidising polymer containing organic groups
3 A method as claimed in Claim 2, characterised in that the monomer is a saturated monomer selected from the group consisting of siloxanes, fluorinated compounds, lower hydrocarbons, lower alcohols, lower alkylamines and mixtures thereof.
4. A method as claimed in Claim 2, characterised in that the monomer is an unsaturated monomer selected from the group consisting of acrylic esters, methacrylic esters, vinyl esters, vinyl aromatics, unsaturated or polyunsaturated hydrocarbons and mixtures thereof.
5. A method as claimed in Claim 4, characterised in that the monomer is selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, vinyl acetate, styrene, -chloromethylstyrene, 2-vinylpyridine, 4-vinylpyridine, N- vinylpyrrolidone, vinyl halides of the formula 
X in Cl or F, vinylidene halides of the formula 
independently Cl or F, vinyl ethers of the formula 
wherein R is alkyl, and allyl derivatives such as allyl ethers, allyl carbonates or diallyl carbonates.
A method as claimed in Claim 1 or Claim 2, characterised in that the plastics material is an acrylic polymer and the polymer coating is a siloxane or perfluorinated compound
7. A method as claimed in Claim 6, characterised in that the polymer is produced from a monomer selected from the group consisting of hexamethyldisiloxane, vinyltrimethoxysilane, perfluorocyclohexane and tetrafluoroethylene.
8. A method as claimed in Claim 1 or Claim 2, characterised in that the plastics material is to be used in an environment where it is exposed to hydrophobic molecules and the polymer coating is a hydrophilic coating.
9. A method as claimed in Claim 8, characterised in that the polymer is produced from a monomer produced from an alcohol or alkylamine.
10. A method as claimed in Claim 9, characterised in that the polymer is produced from an alcohol selected from the group consisting of methanol, ethanol and the various isomers of propanol or butanol.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU17599/97A AU712565B2 (en) | 1996-02-21 | 1997-02-21 | Method for reducing crazing in a plastics material |
| DE19781581T DE19781581T1 (en) | 1996-02-21 | 1997-02-21 | Process for reducing cracking in a plastic material |
| US09/125,023 US6514573B2 (en) | 1996-02-21 | 1997-02-21 | Method for reducing crazing in a plastics material |
| GB9818099A GB2326165B (en) | 1996-02-21 | 1997-02-21 | Method for reducing crazing in a plastics material |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPN8203 | 1996-02-21 | ||
| AUPN8203A AUPN820396A0 (en) | 1996-02-21 | 1996-02-21 | Method for reducing crazing in a plastics material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1997031034A1 true WO1997031034A1 (en) | 1997-08-28 |
Family
ID=3792516
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/AU1997/000101 WO1997031034A1 (en) | 1996-02-21 | 1997-02-21 | Method for reducing crazing in a plastics material |
Country Status (4)
| Country | Link |
|---|---|
| AU (1) | AUPN820396A0 (en) |
| DE (1) | DE19781581T1 (en) |
| GB (1) | GB2326165B (en) |
| WO (1) | WO1997031034A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6108644A (en) * | 1998-02-19 | 2000-08-22 | At&T Corp. | System and method for electronic transactions |
| WO2002004552A1 (en) * | 2000-07-06 | 2002-01-17 | Commonwealth Scientific And Industrial Research Organisation | A process for modifying the surface of a substrate containing a polymeric material by means of vaporising the surface modifying agent |
| US6706320B2 (en) | 2000-07-06 | 2004-03-16 | Commonwealth Scientific And Industrial Research Organisation | Method for surface engineering |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9812457D0 (en) * | 1998-06-10 | 1998-08-05 | Secr Defence | Surface coatings |
| AU2001290097A1 (en) | 2000-10-04 | 2002-04-15 | Dow Corning Ireland Limited | Method and apparatus for forming a coating |
| TW200409669A (en) | 2002-04-10 | 2004-06-16 | Dow Corning Ireland Ltd | Protective coating composition |
| GB0509648D0 (en) | 2005-05-12 | 2005-06-15 | Dow Corning Ireland Ltd | Plasma system to deposit adhesion primer layers |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS588517A (en) * | 1981-07-08 | 1983-01-18 | Sumitomo Electric Ind Ltd | Preparation of composite film with selective permeability for gas |
| EP0176636A1 (en) * | 1984-09-28 | 1986-04-09 | Japan Synthetic Rubber Co., Ltd. | Polymeric thin film and products containing the same |
| WO1989011500A1 (en) * | 1988-05-17 | 1989-11-30 | Commonwealth Scientific And Industrial Research Or | Hydrophilic non-swelling multilayer polymeric materials and process for their manufacture |
| AU7396491A (en) * | 1990-03-30 | 1991-10-03 | Goodyear Tire And Rubber Company, The | Process for the surface treatment of polymers for reinforcement-to-rubber adhesion |
| WO1991016378A1 (en) * | 1990-04-20 | 1991-10-31 | Commonwealth Scientific And Industrial Research Organisation | Cell growth substrates |
| US5494712A (en) * | 1993-08-27 | 1996-02-27 | The Dow Chemical Company | Method of forming a plasma polymerized film |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6013065A (en) * | 1983-07-01 | 1985-01-23 | Stanley Electric Co Ltd | Water repellent treatment of solid surface |
| JPH0222339A (en) * | 1988-07-12 | 1990-01-25 | Hitachi Cable Ltd | Molded product of rubber excellent in ozone resistance |
| IT1244843B (en) * | 1990-11-21 | 1994-09-06 | Donegani Guido Ist | PROCEDURE TO REDUCE THE FRICTION COEFFICIENT AND TO INCREASE THE WATER-REPELLENCE OF BODY SURFACES FORMED IN POLYMERIC MATERIAL |
| US5298587A (en) * | 1992-12-21 | 1994-03-29 | The Dow Chemical Company | Protective film for articles and method |
| EP0705149B1 (en) * | 1993-06-01 | 1998-06-03 | Kautex Textron GmbH & Co. KG. | Method for producing a polymer coating inside hollow plastic articles |
| EP0693975B2 (en) * | 1994-02-16 | 2003-07-30 | The Coca-Cola Company | Hollow containers with inert or impermeable inner surface through plasma-assisted surface reaction or on-surface polymerization |
-
1996
- 1996-02-21 AU AUPN8203A patent/AUPN820396A0/en not_active Abandoned
-
1997
- 1997-02-21 WO PCT/AU1997/000101 patent/WO1997031034A1/en active Application Filing
- 1997-02-21 DE DE19781581T patent/DE19781581T1/en not_active Ceased
- 1997-02-21 GB GB9818099A patent/GB2326165B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS588517A (en) * | 1981-07-08 | 1983-01-18 | Sumitomo Electric Ind Ltd | Preparation of composite film with selective permeability for gas |
| EP0176636A1 (en) * | 1984-09-28 | 1986-04-09 | Japan Synthetic Rubber Co., Ltd. | Polymeric thin film and products containing the same |
| WO1989011500A1 (en) * | 1988-05-17 | 1989-11-30 | Commonwealth Scientific And Industrial Research Or | Hydrophilic non-swelling multilayer polymeric materials and process for their manufacture |
| AU7396491A (en) * | 1990-03-30 | 1991-10-03 | Goodyear Tire And Rubber Company, The | Process for the surface treatment of polymers for reinforcement-to-rubber adhesion |
| WO1991016378A1 (en) * | 1990-04-20 | 1991-10-31 | Commonwealth Scientific And Industrial Research Organisation | Cell growth substrates |
| US5494712A (en) * | 1993-08-27 | 1996-02-27 | The Dow Chemical Company | Method of forming a plasma polymerized film |
Non-Patent Citations (1)
| Title |
|---|
| DERWENT ABSTRACT, Accession No. 90-070437; & JP,A, 02 022 339 (HITACHI CABLE KK), 25 January 1990. * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6108644A (en) * | 1998-02-19 | 2000-08-22 | At&T Corp. | System and method for electronic transactions |
| WO2002004552A1 (en) * | 2000-07-06 | 2002-01-17 | Commonwealth Scientific And Industrial Research Organisation | A process for modifying the surface of a substrate containing a polymeric material by means of vaporising the surface modifying agent |
| US6706320B2 (en) | 2000-07-06 | 2004-03-16 | Commonwealth Scientific And Industrial Research Organisation | Method for surface engineering |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2326165B (en) | 2000-08-09 |
| GB9818099D0 (en) | 1998-10-14 |
| AUPN820396A0 (en) | 1996-03-14 |
| GB2326165A (en) | 1998-12-16 |
| GB2326165A8 (en) | 1999-01-05 |
| DE19781581T1 (en) | 1999-04-29 |
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