Polysiloxane coating with hybrid copolymer.

(54) Title: POLYSILOXANE COATING WITH HYBRID COPOLYMER.

(54) Title: POLYSILOXANE COATING WITH HYBRID COPOLYMER.

(57) Summary

A coating that includes the reaction product of (a) a hybrid copolymer that incorporates (i) a first monomer that includes a hydroxy-functional organoacrylate and (ii) a second monomer that includes an organoalkoxysilane and (b) a second material that includes an organofunctional alkoxysilane. The first monomer can be a hydroxy functional acrylate and / or a hydroxyalkylacrylate. The second monomer can be a trialkoxysilane. The second material can be a trialkoxysilane.

(57) Abstract

A coating ineludes the reaction product of (a) a hybrid copolymer incorporating (i) a first monomer including a hydroxyfunctional organoacrylate and (¡i) a second monomer including an organoalkoxysilane and (b) a second material including an organofuncfional alkoxysilane. The first monomer can be a hydroxy funcfional acrylafe and / or a hydroxyalkylacrylafe. The second monomer can be a trialkoxysilane. The second material can be a trialkoxysilane.

Institute

Mexican Property

Industrial

I KNOW

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PATENT TITLE NO. 344634

Owner (s): PPG INDUSTRIES OHIO, INC.

Address: 3800 West 143rd Street, Cleveland, Ohio, 44111, USA

Denomination: POLYSYLOXANE COATING WITH HYBRID COPOLYMER

Classification: lnt.CI.8: C08G77 / 442; C08L33 / 14; C08L43 / 04; C08L83 / 04; C08L83 / 10; C09D183 / 04; C09D183 / 10

Inventor (s): JOHN D. BASIL; ROBERT M. HUNIA; LAURA B. MCGRADY

REQUEST

Number: International filing date

MX / a / 2012/002025 July 26, 2010

PRIORITY

Country: Date: Number:

US August 19, 2009 12 / 543,615

Validity: Twenty years

Expiration Date: July 26, 2030

The reference patent is granted based on articles 1^or, 2nd fraction V, 6^or fraction lll, and 59 of the Industrial Property Law.

In accordance with Article 23-of the Industrial Property Law, this patent has a validity of one year, non-extendable, counted from the date of presentation of the international application and will be subject to the payment of the tax to keep it in force. rights.

-Whoever signs the titleholder does it based on the provisions of the arucubs S ° fractions ΊΙ and 7 “bis 2 of the Industrial Property Law (Official Gazette of the Federation (DOF) 06/27/1991, amended on 02 / 08/1994, 10/26/1996, 12/26/1987, 05/17/1999, 01/26/2004, 06/16/2005, 01/25/2006, 05/06/2009, 06/01 / 2010, 06/18/2010, 0/28 &amp; 2010, 01/27/2012 and 04/04/2012); items 0, 3^or Section V subsection a), 4 and 12 sections I and III of the Regulation d = l Mexican Institute of Industrial Property (DOF 12/14/1996, amended on 07/01/2002, 07/07/2004, 07/28 / 2004 and 7/09/2007); items 1^or, Vl «M &lt;16 fractions I and lll and 30 of the Organic Elíatuto ¡jdel Instituto Mexicano φ Industrial Property (DOF 12/27/1999, refórmáete« et Wf8 / 2002, 07/29/2004, 08/04/2004 and 09/13/2007); 1^or, 3 ° «5 ° subsection a) of the Agreement that detects powers in the Deputy General Directors, Coordinator, Divisional Directors, Heads of the

Regional Queens, Divisional Deputy Directors, Departmental Coordinators and other subordinates of the Mexican Institute of Industrial Property (DOF 12/15/1999, amended on 02/04/2000, 07/29/2004, 08/04/2004 and 09/13/ 2007).

Issue Date: January 4, 2017

THE DIVISIONAL DIRECTOR OF PATENTS

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POLYSYLOXANE COATING WITH COPOLYMEROTHWW)

BACKGROUND OF THE INVENTION

Field of the invention

The present invention relates generally to protective coatings and, in a particular embodiment, to a flexible siloxane-based polymeric coating incorporating a hybrid polymer.

Technical considerations

In the aviation industry, aircraft windows commonly incorporate a plastic substrate, such as a polycarbonate or a stretched acrylic substrate. These plastic substrates provide excellent safety performance and are lighter than conventional substrates, reducing the overall weight of the aircraft. It is known to apply a protective, abrasion resistant coating on the plastic substrate in order to protect the substrate against mechanical and / or chemical damage during aircraft operation. For example, some commercially available protective coatings contain colloidal silica. However, these coatings can exhibit poor resistance to solvents, such as acetone and sulfuric acid. Other commercially available protective coatings are based on soft organic polymeric systems such as urethanes or melamines.

In an effort to improve the protection of the underlying substrate, tougher and stronger polysiloxane-based coatings have been developed.

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INSTITUTO MEXICANO Dt LA F * 3RIE »AD INDUSTRIAL

These harder coatings provide greater protection compared to the earlier softer coatings. However, these hard coatings are less flexible in nature than earlier softer coatings.

Therefore, it is advantageous to provide a protective coating that provides not only excellent scratch, abrasion and chemical resistance of the polysiloxane coating but also greater flexibility to better withstand the stretching or deformation of the natural substrate that may occur during operation. of the airplane.

SUMMARY OF THE INVENTION

A method of manufacturing a coating that comprises forming a hybrid copolymer comprising (i) a first monomer comprising a hydroxy functional organoacrylate and (ii) a second monomer comprising an organoalkoxysilane. The hybrid copolymer can be formed through free radical polymerization. The method further includes providing a second material (eg, a monomer) capable of reacting with and polymerizing with the hybrid copolymer. The second material is reacted in the presence of the hybrid copolymer, for example, by condensation polymerization, to form the polysiloxane of the invention. This allows the second material to react with the hybrid copolymer as well as undergo polymerization with it, for example by means of condensation polymerization, providing a mechanism for direct chemical bonding between the two polymeric components.

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The first monomer may comprise a hydroxy functional acrylate and / or a hydroxyalkylacrylate. The second monomer may comprise an organofunctional alkoxysilane, such as silicon alkoxide with a polymerizable group. The second material may comprise an alkoxysilane, such as an organoalkoxysilane, such as an alkylalkoxysilane, such as a mono-, di-, tri- and / or tetra-alkoxysilane, or any combination thereof, such as an alkyltrialkoxysilane.

The coating comprises the reaction product of (a) a hybrid copolymer comprising (i) a first monomer comprising a hydroxy functional organoacrylate and (ii) an organoalkoxysilane and (b) a second monomer comprising an organoalkoxysilane. The first monomer may comprise a hydroxy functional acrylate and / or a hydroxyalkylacrylate. The second monomer may comprise an organofunctional alkoxysilane, such as silicon alkoxide with a polymerizable group. The second material may be an alkoxysilane, such as an organoalkoxysilane, such as an alkylalkoxysilane, such as a mono-, di-, tri- and / or tetra-alkoxysilane, or any combination thereof, such as an alkyltrialkoxysilane.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used herein, it is to be understood that all numbers expressing dimensions, physical characteristics, processing parameters, component amounts, reaction conditions, and the like, used in the specification and claims can be modified in all cases for the term approximately.

Accordingly, unless otherwise indicated, the numerical \} ^ res explained in the following specification and in the claims may vary depending on the desired properties that are intended to be obtained by means of the present invention. At least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical value should be interpreted in light of the number of significant digits presented and by the application of common rounding techniques. Furthermore, it is understood that all ranges described herein encompass the start and end values ​​of the range and any sub-ranges subsumed therein. For example, a range from 1 to 10 should be considered to include any sub-ranges between (and including) the minimum value of 1 and the maximum value of 10; that is, all subintervals that start with a minimum value of 1 or more and end with a maximum value of 10 or less, for example 1 to 3.3, 4.7 to 7.5, 5.5 to 10 and the like. Furthermore, as used herein, the terms "formed on, deposited on, or provided on" mean formed, deposited, or provided on an underlying surface by not necessarily in direct contact therewith. For example, a coating layer formed on a substrate does not exclude the presence of one or more layers of another coating or films thereof of different composition located between the coating layer formed and the substrate. As used herein, the term "film" refers to a coating zone of a desired or chosen coating composition. A layer can comprise one or more films. A ¡Nrrrruro Mexican

DE LA FfAflf.DAD liner or stack of liner may comprise ufiQW more layers. As used herein, the terms "polymeric pullller" include oligomers, homopolymers, or polymers made up of two or more types of monomers, such as copolymers, terpolymers, etc. The term "copolymer" means a polymer that has two or more different monomers. The expressions "zone of visible or visible light" refers to electromagnetic radiation that has a wavelength within the range of 380 nm to 780 nm. The terms "infrared zone" or "infrared radiation" refer to electromagnetic radiation having a wavelength within the range of more than 780 nm to 100,000 nm. The terms "ultraviolet zone" or "ultraviolet radiation" mean electromagnetic energy having a wavelength within the range of 100 nm to less than 380 nm. Additionally, all documents, such as, but not limited to, issued patents and patent applications, to which this document refers are to be considered to be incorporated by reference in their entirety.

For the purposes of the following discussion, the in vention is described below with reference to its use as a vehicle transparency element, in particular as a window-shaped aircraft transparency element for aircraft. However, it is understood that the invention is limited to use in aircraft windows, but could be practiced on transparency elements in any desired field, such as, but not limited to, laminated or non-laminated commercial and / or residential windows, insulating glass units and / or transparency elements for vehicles tNSTtTVTO MEX4CAN0 JR tx la rtort «&gt; At Oww'SSLJJSr táourmAi therefore, it must be understood terrestrial, aerial, space, marine or submarine. Because the specifically described exemplary embodiments are presented solely to explain the general concept of the invention and that the invention is not limited to these specific exemplary embodiments.

The coating of the invention incorporates a polymer that exhibits polysiloxane-based hard coating functionality as well as more flexible organopolymer f unctionality, such as but not limited to acrylic or epoxy functionality. Exemplary protective coatings of the invention can be prepared as shown below and as described in the following examples.

A hybrid copolymer is prepared which has at least different monomer units. In a particular non-limiting embodiment, the hybrid copolymer is a copolymer prepared from the reaction product of (i) a first monomer comprising a hydroxy functional organoacrylate and (ii) a second monomer comprising an organofunctional alkoxysilane, such as a silicon alkoxide with a polymerizable group.

In a non-limiting embodiment, the first monomer comprises a hydroxyacrylate and / or a hydroxyalkylacrylate. In general, the alkyl part of the hydroxyalkylacrylate can be represented by the formula C_nH2_n+ i where n is in the range 1-20, such as 1-10 such as 1-5. Specific examples of the first monomer include, but are not limited to, hydroxymethylacrylate, hydroxyethyl acrylate, and hydroxypropylacrylate.

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MEXICAN INSTITUTE

DB LA PHOP1IDAO

INDUSTRIAL

The second monomer is an alkoxide, such as an organofunctional alkoxysilane, such as an organofunctional trialkoxysilane. The alkoxide can contain alkyl or aryl groups. The silanes of the general formula R can be used_xYes (OR ') 4-_x, where R is an organic radical, R 'is a low molecular weight alkyl radial and x is within the range of 1 to 4. The organic radical of R can be vinyl, methoxyethyl, 3-glucidoxypropyl or 3-methacryloxypropyl , to name a few. In a non-limiting embodiment, the second monomer is a trialkoxysilane of the general formula RSi (OR ') 3, where R is a short to medium chain length organic group capable of undergoing polymerization such as vinyl, 3-glucidoxypropyl or 3-methacryloxypropyl. In a particular embodiment, the second monomer is chosen from methacryloxypropyltrimethoxysilane or vinyltrimethoxysilane.

The first and second monomers are combined with an appropriate catalyst, such as azobisisobutyrolnitrile (AIBN), to form a hybrid copolymer. In the broad practice of the invention, the first and second monomers can be combined in any proportion, such as from 1% by weight to 99% by weight of the first comonomer up to an amount of 99% by weight to 1% by weight of the second. monomer, based on the total weight of the combined monomers, such as 40% to 90% by weight of the first monomer, such as 50% to 80% by weight of the first monomer, such as 60% by weight weight to 80% by weight of the first monomer, such as 70% by weight to 80% by weight of the first monomer, such as 75% by weight of the first monomer. The hybrid copolymer can be polymerized by means of free radical polymerization.

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The second material is reacted in the presence of the hybrid copolymer, for example by condensation polymerization in order to form a polysiloxane polymer. This allows the second material to react with the hybrid copolymer as well as undergo polymerization with it, for example by means of condensation polymerization, providing a mechanism for direct chemical bonding between the two polymeric components. The second material can comprise an alkoxide, such as an organoalkoxysilane. The organoalkoxysilane can be an alkylalkoxysilane or an organofunctional alkoxysilane, such as an organofunctional trialkoxysilane, or a mixture thereof. In a non-limiting embodiment, the second material is trialkoxysilane of the general formula RSi (OR ') 3 where R is a short to medium chain length organic group such as alkyl, vinyl, phenyl, 3-glucidoxypropyl or 3-methacryloxypropyl. In a particular embodiment, the second material is methyltrimethoxysilane.

The hybrid copolymer and the second material can be reacted by any known technique, such as a conventional condensation reaction. Examples of conventional techniques are described in US Patent Nos. 5,693,422; 5,401,579; 6,106,605; 6,180,248 and 6,469,119. The hybrid copolymer and the second material can be combined in any desired proportion, such as from 1% by weight to 99% by weight of the hybrid copolymer up to an amount of 99% by weight to 1% by weight of the second material, based on the total weight of the hybrid copolymer and of the second material, such as from% by weight to 50% by weight of the hybrid copolymer, such as from 10% by weight to! κνπ ”· υΐν MEXiCAN · ΓΗ ΓΗ a PROPIBDA» hybrid copolymer, such as from 10% by weight to 30% by weight of the hybrid copolymer, such as from 15% by weight to 20% by weight of the hybrid copolymer, such as 17% by weight of the hybrid copolymer.

The hybrid copolymer resulting from the invention (that is, the polymer formed from the reaction of the first hybrid copolymer and the second material) can be incorporated into a coating composition that provides scratch, abrasion and chemical resistance, sufficient to resist deformation or stretching of the underlying plastic substrate without cracking or breaking the bond. Acrylic functionality provides better weatherability and adhesion to both acrylic and polycarbonate substrates compared to previous protective hardcoats. In the practice of the invention, the shaping of the hybrid copolymer by copolymerizing a hydroxy functional acrylic monomer with a trialkoxysilap provides a copolymer that can undergo subsequent hydrolysis of the alkoxy groups, resulting in a condensation reaction with the matrix. polysiloxane from the coating solution.

While various aspects of the invention have been described, other variations are contemplated within the scope of the invention. For example, but not limited to, the hybrid copolymer need not be limited to a copolymer having two monomers but could include three or more monomers. For example, the resulting hybrid copolymer could be a terpolymer comprising a hydroxy functional organoacrylate, a silicon alkoxide, and a non-hydroxy functional monomer, such as, but not limited to

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MEXICAN INSTITUTE

OF THE PROPERTY limited to, methylmethacrylate or N-vinylpyrrolidone, or any '^^ Tós cteftíós monomers that undergo a polymerization by means of radicalesTíBres "In addition, the hybrid copolymer is not limited to alkylacrylates, but could incorporate other acrylic functional materials, such as, but not limited to, aromatic acrylates or halogenated acrylates, such as fluoroacrylate. Likewise, in addition to the formation of organic / inorganic hybrid copolymers by means of co-polymerization (with hydroxy functional group) of an organic acrylate or methacrylate monomer with a silicon alkoxide with an acrylate or methacrylate functional group, Said organic-inorganic hybrid copolymers can be formed by combining any organic monomer with any alkoxide compound containing a polymerizable group that can undergo the same type of polymerization reaction. For example, vinyl, alkenyl and styryl functional organosilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, p- (t-butyldimethylsiloxy) styrene and vinyl terminated polydimethoxysilane prepolymer can be polymerized with organic monomers via polymerization thermally or UV initiated free radicals, as can be done with organosilanes with acrylic or methacrylic functional group. Similarly, silicon alkoxides with glucidoxy functional group, bis [methyldimethoxysil] propyl] polypropylene oxide and epoxy-terminated polydimethylsiloxane prepolymer can be copolymerized with organic epoxides by cationic UV or UV polymerization. amine addition polymerization. In addition, monomers capable of undergoing condensation polymerization can be used in order

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INSTITUTO MEXICANO M LA ΡΑβΡΙΗΜΕ) HDUSTRIAl to form a hybrid polyimide, polyamide and urethane copolymers with the appropriate amine functional silicon compounds, such as 1,3bis (aminopropyl) tetramethyldisloxane. Monomers capable of undergoing substitution polymerization can be combined with silicon compounds such as b¡s (trimethylsilyl) bisphenol A in order to form copolymers by means of substitution polymerization. As is recognized by those skilled in the art, various techniques can be employed to purify the hybrid copolymer, for example by means of precipitation or fractionation, in order to obtain hybrid copolymer materials with a narrower distribution of properties and therefore which have an effect on the properties of the coating composition.

A coating composition incorporating the resulting hybrid copolymer of the invention can be applied to at least a portion of a substrate by any conventional method such as, but not limited to, spin, dip, spray, or flow coating. , to name a few. In the broad practice of the invention, the substrate may include any desired material exhibiting any characteristics. For example, the substrate can be transparent or translucent to visible light. By transparent it is meant that it has a visible light transmission greater than 0% to 100%. Alternatively, the substrate can be translucent. By translucent we mean allowing electromagnetic energy (for example, visible light) to pass through it, but diffusing this energy in such a way that objects that are on the opposite side to the observer do not

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OF THE NO ^ lERAD

INRUST1IAL are clearly visible. Examples of suitable substrate materials include, but are not limited to, plastic substrates (such as acrylic polymers, such as polyacrylates, polyalkylmethacrylates, such as polymethylmethacrylates, polyethylmethacrylates, polypropylmethacrylates, and the like; polyurethanes, polycarbonate, polyalkylterephthalates such as polyalkylterephthalates (PET) ), polypropylene terephthalates, polybutylene terephthalates and the like, polymers containing polysiloxane; or copolymers of any monomers to prepare these, or any of their mixtures); ceramic substrates; glass substrates; or combinations of any of the above. In a non-limiting embodiment, the substrate is formed of a polymeric material, such as stretched acrylic. However, in other embodiments, the substrate may be a conventional soda-lime-silicate glass, borosilicate glass, lead-containing glass, low-iron glass, lithium doped glass, or lithium alumina silicate glass. The glass layers may be transparent, that is, non-tinted or non-colored glass, or it may be tinted or otherwise colored glass. The glass can be annealed, heat treated or chemically tempered glass. As used herein, the term "heat treated" means tempered or at least partially tempered. The glass can be of any type, such as conventional float glass, and can have any composition having any optical properties, for example, any value of visible transmission, ultraviolet transmission, infrared transmission, and / or total solar energy transmission. The coating of the invention could be used as a single coating stack or it can be combined with other coatings or layers of

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M LA mOWEDAP coating to provide greater functionality. It is also necessary to modify the coating by adding materials such as those normally added to coatings in order to impart additional functionality such as oxide nanoparticles in order to increase hardness and resistance to abrasion. , and UV absorbers and stabilizers.

The following examples illustrate various non-limiting embodiments of the invention. However, it should be understood that the invention is not limited to specific examples.

Hybrid copolymer formation

Example 1

The following ingredients were combined in a glass container: 70 grams (g) of Dowanol PM glycol ether, 22.5 g of 2-hydroxypropylacrylate, 7.5 g of ymethacryloxypropyltrimethoxysilane and 0.06 g of azobisisobutyrolnitrile (AIBN). The solution was degassed for 5 minutes under vacuum, purged with nitrogen by means of a bubbler for 5 minutes, and placed in a nitrogen filled oven at 180 ° F overnight. The mixture was stirred several times during the first hour.

Example 2

45 g of 2-hydroxypropylacrylate, 15 g of γmethacryloxypropyltrimethoxysilane and 0.12 g of azobisisobutyrolnitrile (AIBN) were added to 140 g of glycol ether Dowanol PM in a glass container containing a magnetic stirrer bar. The container was placed in an ultrasound bath for

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INSTITUTE M1XICANC

PROPERTY OF inmistwal 'SCSI- · -five minutes to promote dissolution of AIBN, degassed in a vacuum desiccator for 15 minutes and transferred to a nitrogen purge reaction setup consisting of a 3-minute round bottom flask. 250 milliliter (mi) necks that was equipped with a reflux condenser, a heating device, and a nitrogen sparger and heated to about 80 ° C overnight under nitrogen. The mixture was allowed to cool to room temperature.

Example 3

45 g of hydroxypropylacrylate (mixture of isomers), 15 g of γmethacryloxypropyltrimethoxysilane and 0.12 g of azobisisobutyrolnitrile (AIBN) were added to 140 g of glycol ether Dowanol PM to a glass container containing a magnetic stirrer bar. The solution was stirred for 2-3 minutes to dissolve most of the AIBN, placed in an ultrasonic bath for five minutes, degassed in a vacuum desiccator for 30 minutes, and transferred to a nitrogen purge reaction setup. which consisted of a 250 ml 3 neck round bottom flask equipped with a reflux condenser, a heating device and a nitrogen sparger. After 10 minutes of intense nitrogen purge through the solution, heating with magnetic stirring was started. After 45 minutes of heating, the nitrogen purge was slowed to a minimum and the temperature reached 50 ° C. The heat was increased so that the reaction temperature reached 62 ° C with another 10 minutes, 78 ° C in 20 minutes, at which time the

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reaction was exothermic. The temperature peaked at 107-108 ° C 15 minutes later, after which dlSM influenced the exotherm and the reaction mixture was cooled to 70 ° C. After eight hours, the heat increased again so that the reaction mixture reached 110 ° C in 1 hour, at which time it was removed and the reaction mixture was allowed to cool slightly before use to prepare the solution of coating. Example 4

Azobisisobutyrolnitrile (AIBN) was recrystallized three times from methanol one week before use. Similar to Example 3 above, the three ingredients were directly combined in a 500 ml 3-neck flask equipped with a reflux condenser, heating device, and nitrogen sparger. Γ-Methacryloxypropyltrimethoxysilane was added to the hydroxypropylacrylate, which was subsequently added in 3 minutes to the Dowanol PM glycol ether in the round bottom flask. After five minutes of stirring at room temperature, heating began. Twenty minutes later the temperature of the solution reached 50 ° C and 0.10 g of AIBN dissolved in 10-15 ml of Dowanol PM was added by means of a syringe through a rubber stopper. Forty minutes later the temperature of the reaction mixture had reached the maximum of 119 ° C (60 minutes after the start of the reaction), after which it decreased to 83 ° C and was held until the total reaction time was 16 hours. After cooling to room temperature, the copolymer product was used to prepare a solution of

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IMPI INSTITUTO MEXICANO DE LA MONEDAD INDUSTRIAL polysiloxane coating. Material not used immediately was transferred to a brown glass bottle and stored in a refrigerator. After seven weeks of refrigerated storage, the room temperature viscosity of the product solution was 61.1 centipoise (cps).

Example 5

Azobisisobutyrolnitrile (AIBN) recrystallized once was recrystallized from methanol before use. Similar to Example 3 above, the three ingredients were directly combined in a 250 ml 3-neck round bottom flask. First, γ-methacryloxypropylmethoxysilane was added to the hydroxypropylacrylate and subsequently the mixture of the two monomers was added with stirring to 130 g of Dowanol PM glycol ether solvent (130 g) that had been purged with nitrogen in the 3-neck flask. for 2 hours. Heating began immediately, the reaction solution reaching 56 ° C after 24 minutes, at which time 0.10 g of AIBN was added. The reaction solution reached 117 ° C 45 minutes after the start of the reaction. At approximately 1.25 hours of reaction time, the temperature had dropped to 109 ° F, at which point the heat decreased to maintain the temperature at 86 ° C overnight. After a total time of 16.5 hours from the start of the reaction, the heat was removed to allow the product to cool to room temperature in about one hour. The product was then used to prepare a polysiloxane coating solution or transferred to a brown glass bottle for processing.

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refrigerated storage. After approximately 1 hour of ^^^^^^^^^^^ 0000000 ^ 9000099999999-99999 ^ refrigerated storage, the viscosity of the product at room temperature was 130.6 cps.

Example 6

22.5 g of 2-hydroxypropyl acrylate, 7.5 g γmethacryloxypropyltrimethoxysilane and 0.06 g of dimethoxy-2-phenyl-acetophenone (DMPA) were added to 70.0 g of Dowanol PM glycol ether solvent in a container glass and placed in an ultrasonic bath until DMPA dissolved. Subsequently, the solution was degassed for 10 minutes under vacuum followed by curing for 1 hour at room temperature under a nitrogen atmosphere in an ELC 4001 UV curing unit. The moderately viscous copolymer solution was allowed to cool to room temperature prior to use in preparing the coating solution. Preparation of coating solutions

Method I: In a non-limiting method, copolymer products of the type produced in Examples 1-6 were incorporated into durable, abrasion resistant coating formulations as shown below. In a typical preparation, 15 g of the copolymer product solution was added to 72 g of methyltrimethoxysilane. In a separate container, 15 g of methanol were combined with 44.1 grams of Snowtex O aqueous colloidal silica sol (commercially available from Nissan Chemical) and 3.6 g of glacial acetic acid and 1 drop of concentrated nitric acid. Was added

INSTITUTO MÍXICANO or. the nonWAU slowly the mixture of silane and copolymer to dissolve SRVSS '^ cuo ^ axon magnetic stirring. Stirring continued during the iTOtTreTT ^^ riorml ^ diluted the solution with 125 g of 1-propanol, 0.3 g of BYK-306 (commercially available from BYK Chemie) and 0.75 g of tetramethylammonium hydroxide in methanol (commercially available in Fischer Scientific). Method II: In an alternative non-limiting method, 15 g of copolymer products from Examples 1-6 were combined with 72 g of methyltrimethoxysilane and 45 g of NPC-ST colloidal silica sol in glycol ether PM (commercially available from Nissan Chemical ). In a separate container, 30 g of deionized water were combined with 3.6 g of glacial acetic acid and 1 drop of concentrated nitric acid. The water-acid mixture was slowly added to the silane / copolymer / silica mixture with magnetic stirring, which continued overnight. The solution was subsequently diluted with 100 g of 1-propanol, 0.3 g of BYK-306 (commercially available from BYK Chemie) and 0.75 g of 25% tetramethylammonium hydroxide in methanol (commercially available from Fisher Scientific).

The coatings were applied on acrylic substrates by means of flow coating followed by drying in ambient air for 20-30 minutes and heat cure at 80 ° C for 4 hours.

Test procedures

The properties of the coatings were determined by subjecting them to the following standard procedures.

Adhesion testing was conducted as shown in ASTM D3359

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INSTITUTE msxkano with a modification based on the use of an alternative tape that provides greater adhesion to polysiloxane-type coatings.

Abrasion resistance was measured by Taber abrasion according to ASTM D-1044 using CS-10F wheels, 500 g ea, 100 cycles on 4x4 samples.

Crack resistance was carried out as described in MIL-P25690B but with 75% H2SO4 in place of the organic solvents as the crack initiation medium. For most of the tests, the samples were also subjected to damage by scoring with 0000 steel wool and cutting with a razor prior to testing. Occasionally, samples were preconditioned by immersion for 16 h in water at 60 ° C, continuous moisture condensation at 140 ° F, or 100 h exposure QUV-B313 in accordance with ASTM G-53.

The flexibility of the coatings was determined by fixing 1x12x coated samples^1/4 to different mandrels with a radius of curvature that varied from 14 to 6 and calculating the% stretch at which the coating fractured.

Exposure to condensation moisture was performed on 2 x 6 test specimens evaluated in a Cleveland QCT Q-Panel Condensation Tester at 140 ° F, 100% RH as in ASTM D4584.

Accelerated UV exposure testing was carried out on 3 x 4 test specimens evaluated in an Accelerated Wear Device at

IMPI Mexican institute

Weathering QUV (Q-Panel Company, Cleveland, OH), de ^INS6lT ^ do with the procedure specified in ASTM G-53. The -QUV U ^ Tomblfias UVB313 test and a cycle of 4 hours of condensation at 50 ° C without light, followed by 8 hours of exposure to UV light at 65 ° C.

Test result

Sample 1

Coating compositions were prepared according to Method I described above with the copolymer of Example 1. Samples of 1 x 7 x 0.33 and 4 x 4 x 0.35 of stretched acrylic substrate were coated with the coating composition, they were air dried under ambient conditions for 20 minutes and oven cured for 4 hours at 180 ° F. The coating appeared transparent and smooth. The cured coating exhibited good adhesion and the thickness of the cured coating was measured at 3.75-4.75 microns. After 100 Taber abrasion cycles, 8.2% gloss was measured. No cracking was observed after 1 hr at 3500 psi. After 16 h, no considerable cracking was observed, only two small cracks in a deep line. The coating changed little during the next 17 total days of testing.

Localized substrates were tested according to the QUV test described above and no change was seen after 1600 hours.

Sample 2

Coating compositions were prepared according to Method II described above with the copolymer from Example 3. When applied to a stretched and cured acrylic substrate as described above, the coatings exhibited a US cured film thickness tj micrometers with good adhesion, they exhibited good adhesion. a 4.8% gloss after 500 Taber abrasion cycles and showed no appreciable gloss after 60 minutes.

Sample 3

Coating compositions were prepared according to Method II described above with the copolymer of Example 5 and applied to a stretched acrylic substrate. The coatings were 4 to 7 microns thick and exhibited good adhesion to the substrate, 3 to 5% gloss after 10,500 Taber abrasion cycles, 1.5 to 2% stretch, and more than 1 hour exposure to water. stress test until cracking with sulfuric acid.

Those skilled in the art will readily appreciate that modifications of the invention can be made without departing from the scope of the concepts described in the foregoing description. Accordingly, the particular embodiments described in detail herein are illustrative only and do not limit the scope of the invention which is given by the full breadth of the appended claims and any equivalents thereof.