WO1992021492A1

WO1992021492A1 - Moisture resistant glass article

Info

Publication number: WO1992021492A1
Application number: PCT/US1992/003414
Authority: WO
Inventors: Wells C. Cunningham; Kenneth L. Crouse
Original assignee: Advanced Glass Treatment Systems
Priority date: 1991-05-31
Filing date: 1992-04-27
Publication date: 1992-12-10
Also published as: AU1927092A

Abstract

A glass article having improved resistance to moisture driven strenght degradation includes a glass substrate and a layer of a cured reactive coating composition coated on a surface of the substrate. The reactive coating composition includes from about 10 weight percent to about 74 weight percent of a film forming monomer having two (meth)acryloyl groups per molecule; from about 5 weight percent to about 50 weight percent of a reactive crosslinking monomer having at least three (meth)acryloyl groups per molecule; from about 20 weight percent to about 60 weight percent of a fluorinated (meth)acrylate monomer; from about 1 weight percent to about 30 weight percent of an organosilane monomer having one or more functional groups capable of reacting with the glass substrate and having a nonhydrolyzable organic functional group capable of reacting with a (meth)acryloyl group and an effective amount of a polymerization initiator compound. A method for increasing the resistance of a glass article to moisture driven strength degradation includes applying a layer of the above described reactive coating composition and then curing the layer, preferably by irradiating the coated article with high intensity UV radiation.

Description

MOISTURE RESISTANT GLASS ARTICLE

Technical Field:

The present invention relates to strength

enhancement of glass articles and more particularly to reduction of the detrimental effects of moisture on the strength of glass articles.

Background of the Invention:

It is well known that stress concentration at surface flaws, e.g. nicks, scratches, of a glass article result in a reduction of the strength of the glass article.

It is also known that exposure of a glass article to moisture, e.g. to liquid water or to a humid

environment, results in a gradual degradation of the strength of the article over time. It is believed that chemically adsorbed moisture reacts with siloxane bonds to form hydroxyl bonds at flaw sites on the article surface to form hydroxyl groups, thereby further weakening the flaw sites and gradually degrading the strength of the glass article. Problems associated with reduction in the strength of glass articles due to surface flaws and with time and temperature dependent strength reduction due to gradual moisture driven degradation are particularly acute with regard to glass containers which contain pressurized contents, e.g. bottles for carbonated beverages.

The immediate reduction in container strength due to surface flaws and the time dependent moisture-driven degradation of container strength are conventionally addressed by overdesign, i.e. by taking projected reductions in container strength into account in the design of the container and producing more massive containers having a correspondingly higher initial theoretical strength to compensate for the projected strength reductions. A method which provides an increase in container strength would allow increased efficiency with regard to both material use, i.e. a reduction in container mass, and container production rate, i.e. other factors being equal, a reduction in container mass allows an increase in container

production rate, primarily due to more rapid cooling of the containers during processing.

Flaw-related strength reduction of glass

containers has been addressed in several ways, each typically employed as an adjunct to the above discussed approach of overdesigning the container to compensate for projected strength losses. Damage prevention coatings, i.e. conventional inorganic "hot end"

coatings and organic "cold end" coatings, are used as protective layers to reduce the occurrence of surface flaws. Coatings intended to contain glass fragments from fractured glass bottles are also known. A method for increasing the strength of glass containers which ostensibly allows a reduction in container mass is described in U.S. Patent Nos.

4,891,241 (Hashimoto et al '241) and 4,961,976

(Hashimoto et al '976). The method of Hashimoto et al comprises applying a reactive coating material to a glass container treated with a silane coupling agent or applying a mixture of the coating material and the silane coupling agent to the glass container and then irradiating the coated container to cure the coating.

Hashimoto et al demonstrate an increase in the strength of a container under dry conditions. Hashimoto et al also address short term exposure to "severe

conditions", i.e. hot water and/or hot alkaline water, by introducing an acidic component to the coating material in an attempt to increase adhesion of the coating to the glass surface. However, Hashimoto et al do not address long term moisture-driven degradation of container strength and do not address container

breakage under wet conditions.

While increasing the strength of a glass container should allow a reduction in container mass and a correspondingly increased production rate, it is clear that the problem is not fully addressed by increasing only the short term strength of a dry container and that the time dependent moisture-driven degradation of container strength and the long term strength of the container under humid conditions must be taken into account when attempting to produce lightweight glass containers having a long term strength which exceeds the demands of the particular application of the container by a sufficiently wide margin of safety. Summary of the Invention:

A glass article having improved moisture

resistance is disclosed. The container comprises a glass substrate and a coating layer, comprising the cured reaction product of a reactive liquid coating composition, coating a surface of the substrate. The coating composition comprises:

from about 10 weight percent to about 74 weight percent of a film forming monomer having two

(meth)acryloyl groups per molecule; from about 5 weight percent to about 50 weight percent of a crosslinking monomer having at least three (meth)acryloyl groups per molecule; from about 20 weight percent to about 60 weight percent of a fluorinated (meth) acrylate monomer; from about 1 weight percent to about 30 weight percent of an organosilane monomer having one or more

functional groups capable of reacting with the glass substrate and having a nonhydrolyzable organic

functional group capable of reacting with a

(meth) acryloyl group; and an effective amount of a polymerization initiator compound.

A process for increasing the humidity resistance of a glass substrate is disclosed. The process

includes applying a layer of the above described reactive liquid coating composition to a surface of the glass substrate and curing the layer of coating

composition.

In a preferred embodiment, the layer of coating composition is cured by irradiating the coated

substrate with UV radiation at an intensity effective to cure the above described coating composition. Detailed Description of the Invention:

The glass substrate of the present invention may comprise any silica based glass, e.g. borosilicate, soda-lime-silica or quartz glass. Preferably, the glass substrate comprises soda-lime-silica glass.

While the present invention is specifically described by reference to the preferred embodiment of a moisture resistant glass container, it will be

appreciated that the coating composition and process set forth herein may also be used to increase the resistance of other glass substrates to moisture driven degradation of the tensile and/or flexural strength of the substrate to thereby produce moisture resistant glass articles, e.g. optical fibers, fluorescent lighting tubes, CRT tubes, automobile windshields, and glass sheets, other than glass containers.

The film forming monomer may be any reactive liquid monomer having two (meth)acryloyl groups per molecule. The terminology "(meth) acrylate" as used herein signifies that either the methacrylate or the acrylate form of the compound may be used

interchangeably. Suitable film forming di (meth) acrylate monomers include, e.g. di (meth) acrylic esters and di(meth)acrylamides. Di (meth) acrylic esters of alkyl diols, di (meth) acrylic esters of dicarboxylic acids, di(meth)acrylamides of diamino compounds and mixtures thereof. Specific examples of suitable film forming di (meth) acrylate monomers include ethylene glycol di (meth) acrylate, diethylene glycol di(meth)acrylate, triethyleneglycol di (meth) acrylate, polyethyleneglycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di(meth) acrylate

tripropyleneglycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1, 3 butanediol di(meth)acrylate, 1, 4 butanediol di(meth)acrylate, 1, 6 hexanediol

di(meth)acrylate, bisphenol A di(meth) acrylate,

exthoxylated bisphenol A di(rneth)acrylates,

di(meth)acrylosuccinate, di(meth)acryloadipate, N, N' methylene bis-(meth)acrylamide, N, N' benzilidene bis-(meth)acrylamide, and N, N'

hexamethylene bis-(meth)acryl-amide. Ethylene glycol di (meth)acrylate, 1, 3 butanediol dimethacrylate, 1, 6 hexanediol dimethacrylate, neopentyl glycol diacrylate and ethoxylated bisphenol A dimethacrylate are

particularly preferred as the film forming monomer.

The coating material of the present invention may include from about 10 weight percent to about 74 weight percent of the film forming monomer. Preferably, the coating material of the present invention includes from about 20 weight percent to about 66 weight percent of the film forming monomer.

The crosslinking monomer may by any reactive liquid monomer having three or more (meth)acryloyl groups per molecule. Suitable crosslinking monomers include, e.g. (meth)acrylic esters of polyhydric

alcohols having three or more (meth)acrylic functional groups, (meth)acrylamides having three or more

(meth)acrylic functional groups and mixtures thereof. (Meth)acrylic esters of polyhydric alcohols having an MW less than about 550 are preferred as the

crosslinking monomer. Specific examples of suitable crosslinking monomers include trimethylolpropane

tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate,

ditrimethylolpropane tetra(meth)acrylate. dipentaerythritol hexa (meth)acrylate, tri (meth)acrylate of tris(2-hydroxyethyl) isocyanurate and N, N', N" , N" ' terephthallylidenetetraacrylamide. Trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate and triacrylate of tris

(2-hydroxyethyl) isocyanurate are particularly

preferred as the crosslinking monomer.

The coating material of the present invention may include from about 5 weight percent to about 50 weight percent of the crosslinking monomer. Preferably, the coating material of the present invention includes from about 10 weight percent to about 40 weight percent of the crosslinking monomer.

Increasing the relative amount of acrylate

functional monomer tends to increase the cure speed of the present invention but also tends to decrease the strength of the cured coating under humid conditions. Preferably, a coating composition according to the present invention satisfies a further constraint wherein the combined weight of diacrylate film forming monomer and acrylate crosslinking monomer monoacrylate should not exceed 60% of the total weight of the coating composition. If the combined weight of the difunctional film forming monomer and the

polyfunctional crosslinking monomer monoacrylate exceed 60 % of the coating composition, the excess amount should be selected from the group consisting of

dimethacrylate film forming monomers, methacrylate crosslinking monomers and mixtures thereof.

The fluorinated (meth)acrylate monomer of the prhsent invention may be a fluorinated

mono(meth)acrylate monomer or a fluorinated

di (meth)acrylate monomer. The fluorinated mono(meth)acrylate monomer of the present invention may be any fluorinated

mono(meth)acrylate monomer, e.g. mono(meth)acrylate monomers having fluorine substituted alkyl, cycloalkyl, or alkoxy groups and having no fluorine atoms at the alpha carbon atom. Suitable fluorinated

mono(meth)acrylic monomers include:

a) fluorinated alkyl mono(meth)acrylic esters according to the structural formula: ,

wherein:

X = H or F,

R = H or CH₃, and

m = 1 - 12 ; and b) fluorinated cycloalkyl mono(meth)acrylic esters according to the structural formula:

,

wherein:

R = H or CH₃, and

n = 6 - 12; Preferred fluorinated mono(meth)acrylates include 1,1 dihydroperfluorobutyl(meth)acrylate, 1,1,5

trihydroperfluoropentyl (meth)acrylate, 1,1,7,

trihydroperfluoroheptylacrylate, 1,1

dihydroperfluorooctyl(meth)acrylate and 1,1 dihydroperfluorocyclohexylmethyl (meth)acrylate.

The fluorinated di (meth)acrylate monomer of the present invention may be any fluorinated

di (meth)acrylate monomer. Suitable fluorinated

di (meth)acrylate monomers include; e.g.

a) di (meth)acrylic esters of fluorinated

polyethers according to the structural formulae:

wherein :

R = H or CH₃ ,

m = 1 to 16 ;

n = 1 to 26 ;

x = 2 ; and

y = 1 to 2.

It is preferred that the fluorinated

di(meth)acrylate monomer of the present invention comprises a perfluoropoly-etherdiacrylate having a molecular weight between about 1100 and about 2000.

As mentioned above, increasing the relative amount of acrylate functional monomer tends to increase cure speed of the coating composition of the present

invention but to decrease the strength of the cured coating produced therefrom.

The fluorinated acrylate monomers of the present invention provide a very significant and unexpected advantage in that they may be included in the coating composition in relatively high amounts, thereby

allowing the coating composition to be more rapidly cured, without degrading the strength of the cured coating composition.

The fluorinated acrylate monomer of the present invention provides an unexpectedly rapid cure speed. As discussed below, the coating composition of the resent invention is cured by a free radical

polymerization reaction. It is known that free radical polymerization reactions are inhibited by the presence of oxygen. Since oxygen is more soluble in the

fluorinated acrylate monomers of the present invention than in their corresponding non-fluorinated analogs, substitution of a fluorinated monomer for its

non-fluorinated analog would be expected to slow the cure speed of the curing composition. However, as demonstrated in TABLE 1 of Example 1 below,

substitution of a fluorinated acrylic monomer for a non-fluorinated acrylate monomer is not detrimental to the cure speed, but tends, unexpectedly, to increase the cure speed of the coating composition.

The coating material of the present invention may include from about 20 weight percent to about 60 weight percent of the fluorinated (meth)acrylate monomer.

Preferably, the coating material of the present

invention includes from about 20 weight percent to about 46 weight percent of the fluorinated

(meth)acrylate monomer.

The organosilane coupling agent of the coating composition of the present invention may be any

organosilane monomer having one or more groups capable of reacting with the glass substrate and a

nonhydrolyzable organic functional group capable of undergoing reaction to form a chemical bond with the (meth)acrylate monomers described above. Suitable organosilane coupling agents are those of the general formula:

R

R'n - Si - X_(3-n) wherein:

R is a nonhydrolyzable organic functional group which is capable of reacting with a

(meth)acryloyl group, e.g. (meth)acryloxyalkyl, vinyl, allyl, mercaptoalkyl or aminoalkyl, R' is a nonhydrolyzable nonfunctional organic group, e.g. alkyl,

X is a hydroxyl group or hydrolyzable group, e.g. alkoxy, acetoxy, amino or halo, and

n = 0, 1 or 2.

The hydroxyl or hydrolyzable group X is capable of undergoing reaction with, or of undergoing hydrolysis and subsequent reaction with, silanol groups on the glass substrate to chemically bond the organosilane monomer to the surface of the glass substrate. The nonhydrolyzable organic functional group is capable of undergoing reaction with a (meth)acryloyl group of the coating monomers to chemically bond the organosilane monomer within the coating layer. Respective reactions between the hydroxyl or hydrolyzable group X and the glass substrate and between the functional group R and the monomers of the coating composition chemically bond the cured coating layer to the glass substrate.

Preferably, n = 0 or 1, the organic functional group R is a group capable of undergoing free radical polymerization and the hydrolyzable group X is alkoxy. Most preferably, the organic functional group R is (meth)acryloxyalkyl, the nonfunctional organic group R' is methyl or ethyl and the hydrolyzable group X is methoxy or ethoxy. Specific examples of suitable organosilane coupling agents include

3-(meth)acryloxypropyltrimethoxysilane,

3-(meth)acryloxypropyltriethoxysilane,

3-(meth)acryloxypropylmethyldiethoxysilane,

3-(meth)acryloxypropylmethyldichlorosilane, allyltrimethoxysilane, and

vinylmethyldiethoxysilane,

3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimeth oxysilane and p-aminophenyltrimethoxysilane.

Methacryloxypropyltrimethoxysilane and

methacryloxypropylmethyldiethoxysilane are particularly preferred as the organosilane.

Mixtures of two or more organosilane coupling agents are also suitable as the organosilane coupling agent.

The coating material of the present invention may include from about 1 weight percent to about 30 weight percent of the organosilane. Preferably, the coating material of the present invention includes from about 5 weight percent to about 20 weight percent of the organosilane.

The polymerization initiator of the coating composition of the present invention is preferably a photoinitiator which dissociates or decomposes upon exposure to radiation to yield a free radical.

Conventional photosensitizing compounds may be used in combination with the photoinitiator. Photoinitiators which dissociate upon exposure radiation having a wavelength in the range of 40 nm to 400 nm are

preferred. Suitable photoinitiator compounds include, e.g. benzil, benzophenone, camphorquinone, benzoin n-butyl ether, thioxanthone,

2-hydroxy-2-methyl-1-phenyl-propan-1-one,

1-hydroxycyclohexylphenylketone, isopropyl

thioxanthone, 2,2-dimethoxy-2

phenyl-2-benzyl-2-N-dimethylamino and 1- (4-morpholinophenylbutanone). Preferred photoinitiators include 2-hydroxy-2-methyl-1-phenyl-propan-1-one and 1-hydroxycyclohexylphenylketone.

Alternatively, the coating material of the present invention may be heat cured by including a thermal initiator, i.e. a compound which decomposes upon heating to yield free radical, in the coating

composition. The thermal initiator may be substituted for the photoinitiator to provide heat curable

composition or may be included in addition to the photoinitiator to provide a composition that may be cured by heat and/or radiation. Suitable thermal initiators include, e.g. 2, 2 '-azobis (2, 4

dimethylvaleronitrile), 2-2'-azobis (isobutylnitrile), 2, 2' azobis (methylbutylnitrile), 1,

1'-azobis (cyanocyclohexane) and mixtures thereof. 2, 2' azobis (isobutylnitrile) is preferred as the thermal initiator.

The coating material of the present invention may include any effective amount of the polymerization initiator. Preferably, the coating material of the present invention includes from about 5 weight percent to about 20 weight percent of the polymerization initiator.

Alternatively, the polymerization initiator may be omitted from the coating composition, e.g. if the composition is to be cured by exposure to an electron beam.

The coating composition of the present invention is made by combining the various components of the composition and agitating the resultant combination to form a homogenous mixture.

A layer of reactive liquid coating composition is applied to the glass substrate by any convenient method, e.g. dipping, spray coating, flow coating or roll coating.

The coating composition may be diluted with a suitable solvent, e.g. methylethylketone,

tetrahydrofuran, and various additives known in the art, e.g. leveling agents, surfactants, may be added to the coating composition in accord with the demands of the particular application method.

Preferably, a layer of reactive liquid coating having a thickness of between 0.3 um and 30 urn is applied to a surface of the container. Most

preferably, the layer is between 1 um and 10 um thick.

In the case of a cylindrical container, e.g. a beverage bottle, it is preferred that a solventless layer of the reactive coating composition is applied by roll coating.

Preferably, particularly in the case of glass bottles for containing pressurized liquid, the reactive coating composition is applied to the entire exterior surface of the container. Alternatively, the coating composition may be applied only to those surfaces of the container that are most likely to be damaged, e.g. the circumferential surfaces of a cylindrical container.

Preferably, the coating composition is applied to the container within several hours of heat treating the container as described in copending, coassigned U. S. Application No. 537,507 entitled "Method for Enhancing Strength of A Glass Container and Strength Enhanced Glass Container" by W. C. Cunningham et al.

The '507 application describes a method for

increasing the strength of a glass container by heating the container to a temperature near the annealing temperature of the glass, e.g. above about 500 ºC, applying a polymerizable coating composition to the heat treated container, preferably within six hours after the heat treatment, and curing the coating. The coating step may be carried out at any

convenient temperature, e.g. temperatures between about

0°C and about 50°C. Preferably, the coating step is carried out at a temperature between about 15°C and about 35°C.

Preferably, the layer of coating composition is cured by exposing the coated container to high

intensity UV radiation. Suitable sources of high intensity UV radiation include, e.g. medium pressure mercury vapor lamps and high pressure mercury vapor lamps.

The speed with which a coating composition may be cured is an important variable with regard to the practical application of the process of the present invention. The speed at which a given composition may be cured depends upon several variables, i.e. coating thickness, ambient O₂ concentration and the intensity of the radiation to which the composition is exposed.

The intensity of the radiation and the duration of the exposure are chosen to fully cure the exterior surface of the coating, i.e. to provide a "tack free" surface at the interface between the coating and the surrounding atmosphere. Preferably, the coated surface of the container is exposed in air to UV radiation having an intensity of greater than about 200 mW/cm² at a wavelength of between about 200 and about 450 nm for a time period between 0.1 second and 100 seconds.

As mentioned above, oxygen has an inhibitory effect on the free radical polymerization reaction and consequently the presence of oxygen tends to decrease the speed of cure. The cure speed of a given

composition at a given intensity of radiation may be enhanced by carrying out the curing step in an inert, e.g. N₂ atmosphere. EXAMPLE 1

A series of sample compositions were formulated and tested. Each composition was applied to

microscope slides and cured.

Soda-lime silica microscope slides (nominally 1" ×

3" × lmm) were visually inspected for flaws, e.g.

nicks, scratches. Slides exhibiting visually

detectable flaws were discarded. The thickness of each of the remaining slides was recorded. One side of each of the slides was then abraded with 60 mesh grit at about 80 psi. The abraded slides were then soaked in distilled water for 24 hours, allowed to dry in air at ambient temperature and then heat treated in an oven at about 600°C for 1 hour. The heat treated slides were stored in a dessicator.

Slides were removed from the dessicator and curtain coated with 10g of coating formulation. The coated slides were blotted, hung vertically in air for about 10 minutes and blotted a second time.

The coated slides were aligned in a rack and cured by passing the rack under a FUSION SYSTEMS 300 WPI "H bulb" high pressure mercury lamp. The flawed side of each slide was alternately oriented upwardly and downwardly with the successive passes. The slides were subjected to UV radiation at an intensity of about 550 mW/cm² for 1 second per pass. The number of passes required to obtain a tackfree coating was recorded for each side.

The coated slides were either stored under ambient conditions or soaked in distilled water overnight prior to testing. The slides were tested in a INSTRON 1122 testing apparatus using a 4 point bend flexural test fixture with a span ratio of 2 and a crosshead speed of 0.2 in/min with the flawed side of the slide in tension.

The strength enhancement (S.E.) ratio is

determined by comparing results obtained with coated slides and those obtained with noncoated slides under the same test conditions. "Ambient" strength

enhancement values were derived by testing coated slides that had been stored under ambient conditions and tested under ambient conditions. "High Humidity" strength enhancement values were derived by testing coated slides that had been stored submerged overnight in water and tested wet at room temperature. Five to twenty five samples were tested for each coating composition. Results are expressed as arithmetic averages.

Each of the compositions tested included 10 weight percent crosslinking monomer (trimethylolpropane triacrylate), 14 weight percent organosilane monomer (3-methacryloxypropyltrimethoxysilane) and 6 weight percent photoinitiator (2-hydroxy- 2-methyl-1-phenyl-propan-1-one). The weight percent film forming monomer, weight percent

fluoro(meth) acrylate monomer, number of passes to cure (expressed as flaw side/non flaw side), ambient

strength enhancement ratio and high humidity strength enhancement ratio are set forth in TABLE 1 for each coating composition tested. 492

TABLE I

FLUORO(METH) FILM FORMING AMDIENT

ACRYI.ATE^a MONOMER^c S.E. RATIO

HIGH

FORMULAFILM FORMING NUMDER HUMIDITY TION NO . MONOMER^b OF PASSES S .E. RATIO

1 25 22.5 22.5 3/3 1.42 1.37

2 50 10 10 3/2 1.69 1.59

3 0 35 35 5/2 1.63 1.28

4 25 45 0 5/3 1.69 1.55

5 25 0 45 2/2 1.33 1.24

6 50 20 0 3/3 1.73 1.77

7 50 0 20 2/2 1.55 1.59

8 70 0 0 1/1 1.63 1.46

9 0 70 0 7/3 1.70 1.53

10 0 0 70 3/2 1.53 1.31 a. 1.1,5 trihydroperfluorσpentylacrylate

b. 1,3 butanediol dimethacrylate

c. 1,3 butanediol dlacrylate

The results set forth in Table 1 demonstrate that substitution of a fluorinated acrylate, i.e. 1,1,5 trihydroperfluoropentylacrylate, for a non-fluorinated (meth)acrylate, i.e. 1,3 butanediol dimethacrylate or 1,3 butanediol diacrylate, in the coating composition of the present invention tends, unexpectedly, to increase cure speed. EXAMPLE 2

A series of sample compositions were formulated and tested to demonstrate the effect of increasing the weight percent of fluoro (meth)acrylate monomer in several embodiments of the composition of the present invention.

Each of the compositions tested was applied to microscope slides, cured and tested according to the procedure set forth in EXAMPLE 1.

Each of the compositions included 14 weight percent organosilane monomer

(3-methacryloxypropyltrimethoxysilane) and 10 weight percent photoinitiator (2-hydroxy-2-methyl-1-phenylproρan-1-one). The weight percent film forming

monomer, weight percent cross linking monomer, weight percent fluoroacrylate, number of samples (n), number of passes to cure, mean stress, standard deviation (STD

DEV), ambient strength enhancement ratio and high humidity strength enhancement ratio are set forth in

TABLES 2 - 4 for the coating compositions tested.

TABLES 2

HIGH HUMIDITY

FILM FORMING MEAN PERCENT MONOMER^a STRESS (psi) R.E.

FLUORNUMBER STD S.E.

FORMULAINATED (METH) OF PASSES DEV RATIO TION NO. ACRYLATE

noncoated 14 --- 13600 831 6.1 1.00

11 70 0 8 7/3 23710 2053 8.7 1.74 12 45 25^b 9 5/3 23010 1531 6.7 1.69 13 45 25^c 7 3/2 22350 2280 10.2 1.64 14 45 25^d 8 5/3 23690 1180 5.0 1.74 15 45 25^e 10 5/3 24170 1068 4.4 1.78 16 45 25^f 11 5/3 23720 1509 6.4 1.74 a. 1,3 butyleneglycol dimethacrylate

b. 1,1,5 trihydroperfluoropentylacrylate

c. 1,1,7 trihydroperfluoroheptylacrylate

d. 1,1 dihydroperfluorooctylacrylate

e. 1,1 dihydroperfluorooctylmethacrylate

f. 1,1 dihydroperfluorocyclohexylmethylacrylate TABLE 3

AMB IENT

FILM FORMING n MEAN PERCENT

MONOMER^a STRESS (psi) R.E.

FLUORNUMBER STD S.E.

FORMULAINATED (METH) OF PASSES DEV RATIO TION NO. ACRYLATE noncoated 13 ___ 12769 753 5.9 1.00

17 20 46^b 11 2/2 21464 2261 10.9 1.68

18 20 46^c 13 2/2 15068 1053 7.0 1.18

19 20 46^d 12 2/2 21413 703 3.3 1.68

20 20 46^e 13 4/2 15826 884 5.6 1.24

21 20 46^f 10 2/2 21849 699 3.2 1.71

22 20 46^g 13 8/3 16039 1122 7.0 1.26

23 20 46^h 12 2/2 20576 1634 7.9 1.61

24 20 46ⁱ 6 3/2 20443 1589 7.8 1.60 a. 1,3 butyleneglycol dimethacrylate

b. 1,1 dihydroperfluorocyclohexylmethylacrylate

c. cyclohexyl acrylate

d. 1,1 dihydroperfluorooctylacrylate

e. n-octyl acrylate

f. 1,1 dihydroperfluorooctylmethacrylate

g. n-octyl methacrylate

h . 1 , 1 dihydroperf luorobutylacrylate

i . n-butyl acrylate

TABLE 4

HIGH HUMIDITY

MEAN PERCENT

STRESS (psi) R.E.

n

FORMULANUMBER STD S.E.

TION NO. OF PASSES DEV RATIO noncoated 12 ___ 10817 754 7.0 1.00

17 11 2/2 19859 1182 6.0 1.04

18 13 2/2 12684 616 4.9 1.17

19 11 2/2 18066 1658 9.2 1.67

20 12 4/2 14698 814 5.5 1.36

21 12 2/2 17855 1665 9.3 1.65

22 11 8/3 14791 1091 7.4 1.37

23 12 2/2 18606 1081 5.8 1.72

24 12 3/2 18722 938 5.0 1.73

The results set forth in Table 2 indicate that coating compositions in which a fluorinated acrylate is substituted for a portion of the film forming

non-fluorinated monomer exhibit increased cure speed while maintaining a high strength enhancement ratio under humid conditions. The results also indicate that, unlike non-fluorinated acrylate and methacrylate monomers there is no substantial difference in cure speed between a composition which includes a

fluorinated methacrylate monomer and a composition in which the analogous fluorinated acrylate monomer has been substituted. Furthermore, unlike non-fluorinated acrylate and methacyrlate monomers, there is no

substantial difference in cure speed between a

composition which includes a fluorinated

alkyl (meth)acrylate monomer and a composition in which an analogous fluorinated compound having a longer carbon chain length has been substituted.

The results of Tables 3 and 4 indicate that, in general, coating compositions which include fluorinated acrylate and methacrylate monomers provide a faster cure speed and a higher strength enhancement ratio under both ambient and humid conditions than coating compositions in which a non-fluorinated analog has been substituted.

EXAMPLE 3

A series of sample coating compositions were formulated and tested to demonstrate the performance of fluorinated di (meth)acrylate monomers in the

composition of the present invention. Each composition included 10 weight percent

crosslinking monomer (trimethylolpropanetriacrylate), 14 weight percent organosilane monomer

(3-methacryloxyρroρyltrimethoxysilane) and 6 weight percent photoinitiator (2-hydroxy-2-methyl-1-phenylpropan-1-one).

The weight percent film forming monomer, weight percent fluorinated di(meth) acrylate, number of samples tested (n), number of passes to cure (flawed

side/second side), mean stress at break, standard

deviation (STD DEV), percent relative error (PERCENT R.E.) and ambient strength enhancement ratio (S.E.

RATIO) for each of the compositions tested are set forth in TABLE 5. TABLE 5

AMBIENT

FILM FORMING n MEAN PERCENT

MONOMER^a STRESS (psi) R.E.

FLUORINATED NUMBER STD S.E. FORMULADI (METH) OF PASSES DEV RATIO TION NO. ACRYLATE

noncoated 12 --- 11217 1291 11.5 1.00

25 66 0 11 5/2 19396 1820 9.4 1.73

26 20 46^b 11 3/2 19000 1368 7.2 1.69

27 20 46^c 13 5/5 18934 1136 6.0 1.69

28 20 46^d 12 3/2 19201 2052 10.7 1.71

29 20 46^e 13 3/2 21275 1458 6.9 1.93 a. 1,3 butylene glycol dimethacrylate

b. perfluoropolyether diacrylate (MW = 2000)

c. perfluoropolyether diacrylate (MW = 1000)

d. 1,1 dihydroperfluorocyclohexylmethylmethacrylate

e. 1,1 dihydroperfluorocyclohexylmethylacrylate The results of testing under humid conditions, i.e. number of samples tested (n), number of passes to cure (flawed side/second side), mean stress at break, standard deviation (STD DEV), percent relative error (PERCENT R.E.) and ambient strength enhancement ratio (S.E. RATIO) for each of the compositions tested are set forth in TABLE 6.

TABLE 6

HIGH HUMIDITY

MEAN PERCENT

STRESS (psi) R.E.

n

FORMULANUMBER STD S.E.

TION NO. OF PASSES DEV RATIO uncoated 13 — 11217 1291 11.5 1.00

25 9 5/2 18745 1734 9.3 1.70

26 10 3/2 17024 1221 7.2 1.54

27 10 5/5 17349 544 3.1 1.57

28 10 3/2 18318 849 4.6 1.66

29 13 3/2 19241 1446 7.5 1.74

EXAMPLE 4

The performance of a coating composition of the present invention (FORMULATION NO. 30, set forth below) was compared to that of several embodiments of the coating composition described in Hashimoto et al '241 and Hashimoto et al '976. Formulation No. 30 included (by wt %):

40 1-3-butylene glycol dimethacrylate;

26 1,1 dihydroperfluorocyclohexylmethylacrylate 10 trimethylolpropanetriacrylate;

14 3-methacryloxypropyltrimethoxysilane; and

10 2 hydroxy-2-methyl-1-ρhenyl-propan-1-one.

Comparative formulation 1 (CF1), corresponding to Example 33 of the Hashimoto et al patents, included (by parts):

60 bisphenol "A" (2-hydroxypropyl) methacrylate;

20 trimethylolpropane triacrylate;

20 tetrahydrofurfuryl acrylate;

7 3-methacryloxypropyltrimethoxysilane;

1 fluorinated copolymer leveling agent; and 4 1-hydroxycyclohexylphenylketone.

Comparative formulation 2 (CF2), corresponding to Example 40 of the Hashimoto et al patents, included (in parts):

6 urethane diacrylate (aliphatic urethane diacrylate

8804, Radcure, mw = 12000);

20 trimethylolpropane triacrylate;

7 3-methylacryloxypropyltrimethoxysilane;

20 tetrahydrofurfuryl acrylate;

1 fluorinated copolymer leveler; and

4 1-hydroxycyclohexylphenylketone. Comparative formulation 3 (CF3), corresponding to Example 49 of the Hashimoto et al patents, included (by parts):

40 bisphenol A diacrylate;

10 1,6 hexandiol diacrylate;

10 neopentyl glycol diacrylate;

15 trimethylolpropanetriacrylate;

10.9 pentaerythritol acrylate;

5 tetrahydrofurfuryl acrylate;

5 3-methacryloxyproρyltrimethoxysilane;

0.1 ACRONAL 4F leveling agent;

4 1-hydroxycyclohexylphenylketone; and

0.055 p-toluene sulfonic acid.

Comparative formulation 4 (CF4), corresponding to

Example 67 of the Hashimoto et al patents, included (by parts):

60 neopentyl glycol diacrylate;

30.9 tetrahydrofurfuryl acrylate;

5 3-methacryloxypropyltrimethoxysilane;

0.1 ACRONAL 4F;

4 1-hydroxycyclohexylphenylketone; and

0.055 p-toluene sulfonic acid.

Comparative formulation 5 (CF5), corresponding to Example 69 of the Hashimoto et al patents, included (by parts) :

20 dipentaerythritol pentaacrylate;

70.9 dicyclopentenyl acrylate;

5 3-methacryloxyproρyltrimethoxysilane;

0.1 ACRONAL 4F leveling agent;

4 1-hydroxycyclohexylphenylketone; and

0.055 p-toluene sulfonic acid. Comparative formulation 6 (CF6), corresponding to Example 70 of the Hashimoto et al patents, and included (by parts) :

5 dipentaerythritol pentaacrylate;

85.9 dicyclopentenyl acrylate;

0.1 3-methacryloxyρroρyltrimethoxysilane; 4 ACRONAL 4F;

4 1-hydroxycyclohexylρhenylketone; and

0.055 p-toluene sulfonic acid. Each of the coating compositions were diluted to

40 weight percent solids with methyl ethyl ketone and applied to microscope slides, dried in an oven at

60°C for one minute to evaporate the solvent, cured and then tested under ambient and under high humidity conditions according to the procedure set forth in Example 1 above.

The slides were coated under ambient conditions (about 21°C and about 23 % relative humidity).

The results of testing under ambient conditions, i.e. number of samples (n), mean stress at break, standard deviation, percent relative error (% R.E.), number of passes to cure and ambient strength

enhancement ratio are set forth in TABLE 7 for each of the coating compositions tested. The slides were tested in a controlled atmosphere (27 - 29°C, 31 - 34 % R.H.). TABLE 7

AMBIENT

STD. S.E.

n DEV. RATIO

FORMULAMEAN

TION # STRESS % R.E. PASSES noncoated 12 12895 772 5.99 1.00 __

30 10 21506 1515 7.04 1.67 4/2

CF1 11 21974 1021 4.65 1.70 2/1

CF2 11 19001 1356 7.14 1.47 2/1

CF3 11 22390 1370 6.12 1.74 2/1

CF4 11 16793 1746 10.40 1.30 3/3

CF5 11 21687 1213 5.59 1.68 2/1

CF6 10 19746 1553 7.86 1.53 2/1

The results of testing under highly humid

conditions, i.e. number of samples (n), mean stress at break, standard deviation percent relative error (% R.E.), number of passes to cure and high humidity strength enhancement ratio are set forth in Table 8 for each of the coating compositions tested. The slides were tested wet under controlled conditions (27°C, approximately 100 % R.H.) after overnight storage in water. TABLE 8

HIGH HUMIDITY

(After overnight storage in water)

STD. S E

n DEV. RATIO

FORMULAMEAN

TION # STRESS % R.E. PASSES noncoated 9 12051 677 5.62 1.00 ___

30 10 18093 1020 5.64 1.50 4/2

CF1 11 17061 1353 7.93 1.42 2/1

CF2 11 13790 819 5.94 1.14 2/1

CF3 11 14810 907 6.12 1.23 2/1

CF4 11 15926 1266 7.95 1.32 3/3

CF5 11 16330 1651 10.11 1.36 2/1

CF6 11 13380 1824 13.63 1.11 2/1

The results set forth in TABLES 7 and 8 highlight the differences between an embodiment of the coating composition of the present invention (FORMULATION 30) and a number of examples of the coating composition of Hashimoto et al (COMPARATIVE FORMULATIONS 1 - 6). The compositions of Hashimoto et al tend to provide

somewhat faster cure speed than that of the coating composition of the present invention, and provide ambient strength enhancement values ranging from significantly lower than (e.g. CF 4) to somewhat higher than (e.g. CF 3) those provided by the coating

compositions of the present invention. However, the results of TABLE 8 show the high humidity strength enhancement values provided by the comparative formulations are, in all cases,

significantly lower than that provided by the coating composition of the present invention.

While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been

described by way of illustrations and not limitations.

What is claimed is:

Claims

CLAIM 1. A glass article having improved moisture resistance, comprising:

a glass substrate; and

a coating layer coating a surface of the

substrate;

said coating layer comprising the cured reaction product of a liquid coating composition, said coating composition comprising:

from about 10 weight percent to about 74 weight percent of a reactive film forming monomer having two acryloyl or methacryloyl groups per molecule;

from about 5 weight percent to about 50 weight percent of a crosslinking monomer having at least three acryloyl or methacryloyl groups per molecule;

from about 20 weight percent to about 60 weight percent of a fluorinated acrylate or methacrylate monomer;

from about 1 weight percent to about 30 weight percent of an organosilane monomer having one or more functional groups capable of reacting with the glass substrate and having a

nonhydrolyzable organic functional group capable of reacting with an acryloyl or methacryloyl group; and

an effective amount of a polymerization initiator.

CLAIM 2. The article of Claim 1, wherein the glass substrate comprises a material selected from the group consisting of borosilicate glass, soda-lime-silica glass, and quartz glass.

CLAIM 3. The article of Claim 1, wherein the glass substrate comprises a bottle for containing a liquid at superatmospheric pressure, said bottle exhibiting improved resistance to moisture driven degradation of the burst strength and impact strength of the container,

CLAIM 4. The article of Claim 1, wherein the coating layer has a thickness between about 0.1 um and about 20 um.

CLAIM 5. The article of Claim 1, wherein the coating layer is chemically bonded to the surface of the

substrate.

CLAIM 6. The article of Claim 2, wherein the

functional groups capable of reacting with the glass substrate comprise hydroxyl groups or hydrolyzable groups and the hydroxyl groups or hydrolyzable groups are capable of forming chemical bonds with the silanol groups on the surface of the glass substrate.

CLAIM 7. The article of Claim 1, wherein the film forming monomer is selected from the group consisting of ethylene glycol dimethacrylate, 1, 3-butanediol diacrylate, 1, 3-butanediol dimethacrylate, 1, 6

hexanediol dimethacrylate, neopentyl glycol

dimethacrylate, ethoxylated bisphenol A dimethacrylate and mixtures thereof.

CLAIM 8. The article of Claim 1, wherein the

crosslinking monomers is selected from the group consisting of trimethylolpropane trimethacrylate, trimethylolpropanetriacrylate, ditrimethylolpropane tetraacrylate, triacrylate of tris (2-hydroxyethyl) isocyanurate, pentaerythritol triacrylate and mixtures thereof.

CLAIM 9. The article of Claim 1, wherein the

fluorinated acrylate or methacrylate monomer comprises a fluorinated alkyl mono(meth)acrylate ester or a fluorinated cycloalkyl mono(meth)acrylic ester.

CLAIM 10. The article of Claim 1, wherein the

fluorinated acrylate or methacrylate monomer is selected from the group consisting of 1,1

trihydroperfluorobutyl(meth)acrylate, 1,1,5

trihydroperfluoropentyl(meth)acrylate, 1,1,7

trihydroperfluoroheptyl(meth)acrylate, 1,1

dihydroperfluorooctyl(meth)acrylate and 1,1

dihydroperfluorocyclohexylmethyl(meth)acrylate.

CLAIM 11. The article of Claim 1, wherein the

fluorinated acrylate or methacrylate monomer comprises a di(meth)acrylic ester of a polyether.

CLAIM 12. The article of Claim 1, wherein the

organosilane monomer is selected from the group

consisting of methacrylox- propyltrimethoxysilane, methacryloxypropylmethyldiethoxysilane,

acryloxypropyltrimethoxysi1ane,

mercaptopropyltrimethoxysilane

and mixtures thereof.

CLAIM 13. The article of Claim 1, wherein the polymerization initiator is a photoinitiator selected from the group consisting of benzil, benzophenone, camphorquinone, benzoin n-butyl ether, thioxanthone, isopropyl thioxanthone, 2,2-dimethoxy-2-ρhenyl-2-benzyl-2-N-dimethylamino

1- (4-morpholinophenyl╌butanone)

2-hydroxy-2-methyl-1-phenyl-propan-1-one,

1-hydroxycyclohexyl phenylketone, and mixtures thereof.

CLAIM 14. A process for increasing the humidity resistance of a glass substrate, comprising:

applying a reactive liquid coating composition to a surface of the glass substrate, said coating

composition comprising:

from from about 10 weight percent to about 74 weight percent of a film forming monomer having two acryloyl or methacryloyl groups per molecule; from about 5 weight percent to about 50 weight percent of a crosslinking monomer having at least three acryloyl or methacryloyl groups per molecule;

an effective amount of a polymerization initiator; and

curing the coating composition.

CLAIM 15. The process of Claim 14, wherein the film forming monomer is selected from the group consisting of ethylene glycol dimethacrylate, 1,

3-butanedioldimethacrylate, 1, 3-butanedioldiacrylate, 1, 6 hexanediol dimethacrylate, neopentyl glycol diacrylate, ethoxylated bisphenol A

dimethacrylate and mixtures thereof.

CLAIM 16. The process of Claim 14, wherein the

crosslinking monomers selected from the group

consisting of trimethylolpropane trimethacrylate, ditrimethylolpropane tetraacrylate, triacrylate of tris (2-hydroxyethyl) isocyanurate, pentaerythritol

triacrylate and mixtures thereof.

CLAIM 17. The process of Claim 14, wherein the

fluorinated acrylate or methacrylate monomer comprises a fluorinated alkyl mono(meth)acrylate ester or a fluorinated cycloalkyl mono (meth)acrylic ester.

CLAIM 18. The method of Claim 14, wherein the

fluorinated acrylate or methacrylate monomer is

selected from the group consisting of 1,1

trihydroperfluorobutyl(meth)acrylate, 1,1,5

trihydroperfluoropentyl(meth)acrylate, 1,1,7

trihydroperfluoroheptyl(meth)acrylate, 1,1

dihydroperfluorooctyl(meth)acrylate and 1,1

dihydroperfluorocyclohexylmethyl(meth)acrylate.

CLAIM 19. The method of Claim 14, wherein the

fluorinated acrylate or methacrylate monomer comprises a di (meth)acrylic ester of a polyether.

CLAIM 20. The process of Claim 18, wherein the

organosilane monomer is selected from the group

acryloxypropylmethyldichlorosilane and mixtures thereof,

CLAIM 21. The process of Claim 14, wherein the

polymerization initiator is a photoinitiator selected from the group consisting of benzil, benzophenone, camphorquinone, benzoin n-butyl ether, thioxanthone, isopropyl thioxanthone and 2,2-dimethoxy-2

phenyl-2-benzyl-2-N-dimethylamino 1- (4-morpholinophenyl-butanone)

2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-hydroxycyclohexylphenylketone, and mixtures thereof.

CLAIM 22. The process of Claim 14, wherein the coating composition is cured by exposure to radiation having a wavelength from 200 nm to 450 nm at an intensity of greater than 200 mW/cm ² for a t:ime period of about

0.1 second to about 100 seconds,

CLAIM 23. The process of Claim 22, wherein the coating composition is cured in air to provide a tack free coating surface.

CLAIM 24. A coated glass substrate made by the process of Claim 14.

CLAIM 25. The article of Claim 1, wherein the coating composition consists essentially of:

an effective amount of a polymerization initiator.

CLAIM 26. The process of Claim 14, wherein the coating composition consists essentially of:

from from about 16 weight percent to about 75 weight percent of a film forming monomer having two acryloyl or methacryloyl groups per molecule; from about 5 weight percent to about 50 weight percent of a crosslinking monomer having at least three acryloyl or methacryloyl groups per molecule;

from about 10 weight percent to about 60 weight percent of a fluorinated acrylate or methacrylate monomer;

an effective amount of a polymerization initiator.