WO2001010954A1

WO2001010954A1 - Polymerizable compositions

Info

Publication number: WO2001010954A1
Application number: PCT/US2000/019061
Authority: WO
Inventors: Ronald E. Johnson; Khalil M. Moussa; Kimberly S. Wayman
Original assignee: Corning Incorporated
Priority date: 1999-08-05
Filing date: 2000-07-13
Publication date: 2001-02-15
Also published as: AU6093700A

Abstract

The present application describes a composition which includes a carboxylic acid terminated fluoropolyether and a cycloaliphatic epoxy resin as well as objects which includes a polymerization product of such a composition. Materials prepared by a method which includes providing a composition containing a carboxylic acid terminated fluoropolyether and a cycloaliphatic epoxy resin and polymerizing the composition are also disclosed. In addition, the present application describes the use of such materials in optical system which include a first optical component, a second optical component, and the material disposed between the first and second optical components. The compositions of the present invention can be polymerized without use of light or heat.

Description

POLYMERIZABLE COMPOSITIONS

FIELD OF THE INVENTION

The subject invention relates to a polymerizable composition and, more particularly, to a polymerizable composition which includes a carboxylic acid terminated fluoropolyether and a cycloaliphatic epoxy resin.

BACKGROUND OF THE INVENTION

In recent times, the use of optical fiber communications has increased dramatically, and the promise of increased signal transmission speed and clarity makes it likely that the use of optical fibers for signal transmission will continue to increase in the future. Optical fiber technology can be used to transmit a variety of signals. For example, telecommunication, sensor, medical, and video transmissions can all take advantage of optical technology, particularly where virtually unlimited bandwidth and low attenuation are beneficial . Cable television systems are one example where optical fiber technology is providing efficient and economical alternatives to prior coaxial cable distribution schemes. Optical devices for transmitting, conducting, and receiving data are of great interest because of the potential for replacing many electrical circuits with optical circuits. The optical circuits are light in weight, secure, resistant to many types of radiation, and of small dimension. Moreover, more information can be transmitted through an optical line than through an electrical line of comparable size and weight.

In systems designed to optically transmit signals, light is guided through the optical system using optical fibers and waveguides. These optical fibers and waveguides typically include an inner glass core of transparent material surrounded by a glass cladding layer having a lower refractive index than the core. Due to this difference between the index of refraction of the core and the cladding, total internal reflection occurs, and the light entering one end of the fiber or waveguide is internally reflected along .its length. According to the principle of total internal reflection, light entering the fiber or waveguide with the proper entry angle will be internally reflected at the interface between the core and the cladding and will proceed down the length of the fiber or waveguide with multiple internal reflections from the cladding layer surrounding the core, without any loss of intensity regardless of the number of multiple reflections . If the fiber or waveguide is long, there must be such total internal reflection for the fiber or waveguide to be operable, as even a small percentage reduction of light intensity on each reflection would result in insufficient intensity of the beam emerging from the fiber or waveguide. Consequently, the optical fiber or waveguide must be carefully constructed so as to avoid any loss or leakage of light from the waveguide. Therefore, the glass used to construct an optical fiber or waveguide is highly perfect, having a low density of imperfections that could scatter light in a direction which would result in less than total internal reflection at the core/cladding interface.

Presently, optical fibers and waveguides having the necessary low density of imperfections are well known, and losses in signal strength occur primarily at the junction of two optical elements rather than over the even great distances of a single optical fiber. The problem of signal loss at the junctions of optical elements in an optical transmission system is intensified by the fact that optical systems are being increasingly used for local signal transmission. In contrast to long-haul transmissions, where signals are intended to be transmitted many miles without interruption, local transmission systems require many more optical fiber splices .

One method for making optical splices between optical fibers and/or waveguides involves the use of adhesives. Although a wide variety of adhesives having varied refractive indices, optical losses, adhesive strengths, flexibilities, and heat resisting properties are known, those having the optical properties needed for use as an optical adhesive for joining fibers and waveguides in an optical signal transmission system require the use of either heat or light to cure. In many circumstances, the use of heat and/or light is inconvenient, especially in cases where splices need to be made in the field under adverse conditions, frequently without access to specialized equipment. Moreover, the application of heat and light, in some instances, can causes damage to the components being joined.

Accordingly, a need exists for materials that bond optical components, such as fibers and waveguides together without heating, without the use of light, and without causing loss in signal strength or signal quality. The present invention is directed to meeting this need.

SUMMARY OF THE INVENTION

The present invention relates to a composition which includes a carboxylic acid terminated fluoropolyether and a cycloaliphatic epoxy resin.

The present invention also relates to an object which includes a polymerization product of a composition which includes a carboxylic acid terminated fluoropolyether and a cycloaliphatic epoxy resin.

Further, the present invention relates to a material prepared by a method which includes providing a composition which includes a carboxylic acid terminated fluoropolyether and a cycloaliphatic epoxy resin and polymerizing the composition.

The present invention is also directed to an optical system which includes a first optical component, a second optical component; and a material disposed between the first optical component and the second optical component. The material is prepared by providing a composition which includes a carboxylic acid terminated fluoropolyether and a cycloaliphatic epoxy resin and polymerizing the composition.

The compositions of the present invention can be polymerized without the use of light or heat. Accordingly, they are particularly useful as molding compositions or as adhesive compositions, especially for the fabrication of optical components or systems, in cases where it may be desirable to polymerize the composition without the use of light or heat. DETAILED DESCRIPTION OF THE INVENTION

Carboxylic acid terminated fluoropolyethers are meant to include polyethers which have at least one terminal carboxylic acid group and at least one fluorine atom. Preferably, the at least one fluorine atom is bonded to a carbon atom in an ether unit of the polyether, and, more, preferably, the carboxylic acid terminated fluoropolyether has at least 25% of the hydrogen atoms in its ether units replaced with fluorine atoms. For example, carboxylic acid terminated fluoropolyethers useful for the practice of the present invention include those which have more than 25 .mole %, preferably more than 60 mole %, more preferably more than 90 mole %, of ether units selected from: -CF₂-CF₂-0-, -CF₂-0-, -CF(CF₃)-0-, and -CF₂-CF (CF₃) -O- . Such compounds can be made by processes as described in U.S. Patent No. 5,446,205 to Marchionni et al . , which is hereby incorporated by reference and, preferably, have a molecular weight of about 300 to 5000.

Particularly preferred carboxylic acid terminated fluoropolyethers are carboxylic acid terminated perfluoropolyethers, illustrative examples of which are the Fomblin MF series of compounds manufactured by Ausimount Inc. (e.g., Fomblin MF 300) and the Fluorolink series of compounds manufactured by Ausimount Inc. (e.g., Fluorolink C) . As used herein, carboxylic acid terminated fluoropolyethers are meant to include the salts (e.g., the alkali metal and ammonium salts) of the corresponding carboxylic acid terminated fluoropolyethers . Combinations of these and other carboxylic acid terminated fluoropolyethers can also be employed in the compositions of the present invention.

Cycloaliphatic epoxy resins are those containing a cycloaliphatic group (e.g., cyclohexane, cyclopentane) in which hydrogen atoms on each of two adjacent carbons are replaced with a bridging oxygen atom (-0-) . Preferred cycloaliphatic epoxy resins are those which have an epoxy equivalent weight of about 100-300. Commercial examples of representative suitable cycloaliphatic epoxies include 3 , 4-epoxycyclohexylmethyl- 3 , 4-epox cyclohexane carboxylate (e.g. "ERL-4221" from Union Carbide Corp.); bis (3 , 4-epoxycyclohexylmethyl) adipate (e.g. "ERL-4299" from Union Carbide Corporation) ; 3 , 4-epoxy-6-methylcyclohexylmethyl-3 , 4 -epoxy-6- methylcyclohexane carboxylate (e.g. "ERL-4201" from Union Carbide Corp. ) ; bis (3 , 4-epoxy-6-methylcyclohexylmethyl) adipate (e.g. "ER -4289" from Union Carbide Corp.); bis(2,3- epoxycyclopentyl) ether (e.g. "ER -0400" from Union Carbide Corp.); dipentene dioxide (e.g. "ERL-4269" from Union Carbide Corp.); 2- (3 , 4-epoxycyclohexyl-5 , 5-spiro- 3 -4 -epoxy) cyclohexane-metadioxane (e.g. "ERL-4234" from Union Carbide Corp.) . Other commercially available cycloaliphatic epoxies are available from Ciba-Geigy Corporation, such as CY 192, a cycloaliphatic diglycidyl ester epoxy resin having an epoxy equivalent weight of about 154. Other cycloaliphatic epoxy resins can be prepared according to standard methods, such as those set forth in U.S. Patent Nos . 2,750,395, 2,884,408, 2,890,194, 3,027,357, and 3,318,822, which are hereby incorporated by reference. Combinations of these and other cycloaliphatic epoxy resins can also be employed in the compositions of the present invention. Cycloaliphatic polyepoxy resins (i.e., cycloaliphatic epoxy resins which contain two or more epoxide moieties, either on the same cycloaliphatic ring or on different cycloaliphatic rings) , particularly, 3 , 4-epoxycyclohexylmethyl -3 , 4-epoxycyclohexane carboxylate, are preferred. The ratio of cycloaliphatic epoxy resins to carboxylic acid terminated fluoropolyethers present in the composition of the subject invention is generally selected such that the ratio between the number of epoxy moieties and the number of terminal acid moieties is between about 0.2 and about 5, preferably between about 0.5 and about 2, more preferably between about 0.9 and 1.1, and most preferably about 1. When the cycloaliphatic epoxy resin is 3 , 4-epoxycyclohexylmethyl- 3 , 4-epoxycyclohexane carboxylate and the carboxylic acid terminated fluoropolyether is Fluorolink C, the weight ratio of 3,4- epoxycyclohexylmethyl- 3 , 4-epoxycyclohexane carboxylate to Fluorolink C is preferably from about 5:1 to about 2:1, more preferably about 3:1.

The composition of the present invention can also include other ingredients, depending on the intended method of polymerization and the desired properties of the polymerized product produced therefrom.

For example, the compositions of the present invention can further include a non-cycloaliphatic epoxy monomer or oligomer. As used herein, "non-cycloaliphatic epoxy monomer or oligomer" is meant to include any epoxy resin which is not a cycloaliphatic epoxy resin, as described above. Examples of suitable non-cycloaliphatic epoxy monomers and oligomers include non-cycloaliphatic polyepoxides, such as aliphatic and aromatic polyepoxies, such as those prepared by the reaction of an aliphatic polyol or polyhydric phenol and an epihalohydrin. Other useful epoxies include epoxidized oils and acrylic polymers derived from ethylenically unsaturated epoxy- functional monomers such as glycidyl acrylate or glycidyl methacrylate in combination with other copolymerizable monomers such as the (meth) acrylic and other unsaturated monomers. Representative useful (meth) acrylic monomers include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, ethyl hexyl acrylate, amyl acrylate, 3 , 5 , 5-trimethylhexyl acrylate, methyl methacrylate, lauryl methacrylate, butyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, and methacrylamide . Other copolymerizable monomers include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl benzoate, vinyl m-chlorobenzoate, vinyl p-methoxy benzoate, vinyl chloride, styrene, α-methyl styrene, diethyl fumarate, dimethyl maleate, etc. The epoxy-functional monomers, when-used, should normally not contain acid functionality or other functionality reactive with epoxide groups. Particular examples of non- cycloaliphatic epoxy resins suitable for use in the compositions of the present invention include epoxy derivative resins, such as Polyset PC-1000 (available from

Polyset Comapny, Inc., Mechanicsville, New York), EPALLOY™ 5000 (available from CVC, Cherry Hill, New Jersey), bisphenol-A epoxy resins, and novalac epoxy resins. Typically, use of non-cycloaliphatic epoxy resins decreases the rate at which the composition of the present invention cures when compared to compositions containing cycloaliphatic epoxy resins, carboxylic acid terminated fluoropolyethers, and no non-cycloaliphatic epoxy resins. In the case where the polymerization product of the composition is to be used in optical signal transmission, it may be desirable to add materials which are known to reduce optical loss, for example, colloidal silica to the compositions of the present invention. Another component that can optionally be included in the composition of the present invention is a catalyst for the reaction of epoxy and acid groups. Tertiary amines, secondary amines, quaternary ammonium salts, and nucleophilic catalysts, such as lithium iodide, phosphonium salts, and phosphines (e.g., triphenyl phosphine) are especially useful as catalysts for epoxy/acid reactions. The catalyst for the epoxy/acid reaction, if used, will typically be present at a level of at least 0.01% by weight of the total acid-functional polymer and epoxy- functional compound and will preferably be present at about 0.1 to about 3.0%.

The compositions of the present invention can also include a polymerization initiator, such as a photoinitiator or a thermal initiator. For example, in circumstances where the composition of the present invention is to be light-cured, cationic photoinitiators, such as Sartomer CD1010, can be advantageously employed. However, as described in more detail below, the compositions of the present invention can be polymerized at room temperature without the use of light or heat. Accordingly, it is expected that the compositions of the present invention will be substantially free of photoinitiators. For the purposes of the present application, a composition is considered to be substantially free of photoinitiator when the amount of photoinitiator present has an insubstantial effect (e.g., less than 10% increase) on the rate of polymerization when compared to a composition which is completely free of photoinitiator. Further, it is expected that the compositions of the present invention will be substantially free of thermal initiators. For the purposes of the present application, a composition is considered to be substantially free of thermal initiator when the amount of thermal initiator present has an insubstantial effect (e.g., less than 10% increase) on the rate of polymerization when compared to a composition which is completely free of thermal initiator. Compositions of the present invention can also be substantially free of both thermal initiators and photoinitiators .

The composition of the present invention can optionally contain a curing agent, such as a cross-linking agent, for example, anhydrides, particularly, dianhydrides of diacids. In certain applications, particularly in cases where the compositions are being used to form materials to be used in optical signal transmission, it is advantageous to use anhydrides containing chlorine atoms, such as chlorendic anhydride, because, it is believed, the halogenation further reduces optical losses. Moreover, the use of chlorine-containing anhydrides is advantageous, because the chlorine content of the anhydride facilitates counterbalancing the fluorine content of the carboxylic acid terminated fluoropolyethers when attempting to adjust the composition's index of refraction. Examples of suitable anhydrides that can be included in the compositions of the present invention are chlorendic anhydride and hexahydrophthalic anhydride. The composition of the present invention can also include two anhydrides, for example, both chlorendic anhydride and hexahydrophthalic anhydride. Compositions in which chlorendic anhydride and hexahydrophthalic anhydride are present in weight ratios of from about 30:70 to about 50:50 are illustrative of a preferred embodiment of the present invention, as are compositions in which chlorendic anhydride and hexahydrophthalic anhydride are present in weight ratios of about 40:60 and those in which chlorendic anhydride and hexahydrophthalic anhydride are present as a eutectic mixture. Other anhydride-functional compounds which are useful in the practice of this invention include any aliphatic or aromatic compound having at least two cyclic carboxylic acid anhydride groups in the molecule. Polymeric anhydrides, such as acrylic polymers having anhydride functionality and having number average molecular weights between 500 and 7,000 are also useful. These are conveniently prepared, as is well known in the art, by the polymerization under free radical addition polymerization conditions of at least one unsaturated monomer having anhydride functionality, such as maleic anhydride, citraconic anhydride, itaconic anhydride, propenyl succinic anhydride, etc. optionally with other ethylenically unsaturated monomers such as the esters of unsaturated acids, vinyl compounds, styrene-based materials, allyl compounds an other copolymerizable monomers. Other polyanhydrides can also be optionally utilized in the practice of this invention. Ester anhydrides can be prepared, as is known in the art, by the reaction of e.g. trimellitic anhydride with polyols.

Still other representative, suitable anhydrides include poly-functional cyclic dianhydrides such as cyclopentane tetracarboxylic acid dianhydride, diphenyl -ether tetra-carboxylic acid dianhydride, 1 , 2 , 3 , 4 , -butane tetracarboxylic acid dianhydride, and the benzophenone tetracarboxylic dianhydrides, such as 3, 3 ',4,4'- benzophenone tetracarboxylic dianhydride, and 2- bromo-3 , 3 ', 4 , 4 ' -benzophenone tetracarboxylic acid dianhydride . Trianhydrides such as the benzene and cyclohexene hexacarboxylic acid trianhydrides are also useful. When the composition of the present invention includes an anhydride-functional compound along with the cycloaliphatic epoxy resins and carboxylic acid terminated fluoropolyethers compound, the ratios of anhydride to acid to epoxy groups can be widely varied to give any desired level of crosslinking. Typically, the anhydride should be present in an amount to provide at least about 0.01 anhydride groups for each epoxy group in the reactive coating. It is preferred, however, to provide from about 0.3 to about 6.0 acid groups and from about 0.6 to about 12.0 epoxy groups for each anhydride group in the composition. For example, in the case where the composition contains chlorendic anhydride and hexahydrophthalic anhydride in a weight ratio of about 40:60, it is preferred that the ratio of the weight of anhydride mixture to the combined weight of cycloaliphatic epoxy resins and carboxylic acid terminated fluoropolyethers be from about 5 to about 25 %, preferably from about 10 to about 15 %.

The use of cross-linkers, such as the anhydrides discussed above are particularly advantageous in cases where it is desirable that the products of polymerization of the compositions of the present invention have higher Tg ' s . When the composition of the present invention incorporates an anhydride-functional compound along with the acid-functional polymer and the epoxy-functional compound, the ratios of anhydride to acid to epoxy groups can be widely varied to give any desired level of crosslinking within the practice of this invention. Typically, the polyanhydride should be present in an amount to provide at least about 0.01 anhydride groups for each epoxy group in the reactive coating. It is preferred, however, to provide about 0.3 to about 6.0 acid groups and about 0.6 to about 12.0 epoxy groups for each anhydride group in the reactive system. An especially preferred formulation range provides 2.0 to about 5.0 acid groups and 3.0 to about 8.0 epoxy groups for each anhydride group. Typically, when the compositions of the present invention include anhydrides, they usually require a post cure step, for example, using heat or light or both (as discussed further below), to achieve optimal Tg's. Alternatively, higher Tg's can be achieved by including in the composition materials known to promote curing of resins containing cycloalkene oxide (e.g., cyclohexene oxide and cyclopentene oxide) groups. Especially suitable for achieving higher Tg's are metal salts, such as a metal carboxylic acid salts, metal alcoholates, and metal phenolates), particularly metal linear alkanoic acid salts (e.g., zinc octoate and stannous octoate) . Typically, these materials are used in an amount of 0.1 to 1.0 part by weight per 100 parts of composition. The composition of the present invention can be made from its components by combining them using a suitable mixer to form a mixture, preferably a homogenized mixture. For example, the mixing can be carried out with an in-line mixer, especially in cases where the composition is to be used in a process such as reactive injection molding or reactive transfer molding. Optionally, one or more of the components of the composition can be dissolved or suspended in a suitable solvent prior to being mixed with the other components of the mixture.

The compositions of the present invention can be used to produce a variety of articles of manufacture including molded articles, cast articles, sheet materials, sealants, adhesives, encapsulants, coatings, paints (i.e., coatings containing a pigment), and the like.

Applications that will particularly benefit from the compositions of the invention include those which relate to optical signal transmission. Depending on the ultimate use to which the composition is to be put, the composition, prior to polymerization can be formed into a mold, cast into sheets, or disposed on or between other materials. For example, in the case where the composition of the present invention is to be formed into a waveguide it can be cast into an appropriate mold by conventional methods, such as by injection molding. Alternatively, in the case where the composition is to be used as an adhesive between two materials, it is positioned between the materials prior to polymerization.

Once the composition of the present invention is thus provided, it is polymerized to produce a polymerization product. Polymerization can be permitted to take place at room temperature without the use of heat and without the use of light. , For purposes of the present invention, "polymerization" is meant to include partial polymerization to a gel state rather than a hardened state, such as, for example in the case where from about 50% to about 90% of the reactive acid (i.e., the carboxylic acid terminated fluoropolyether) and epoxy groups in the composition have reacted) . For the purposes of the present invention, "without the use of heat" is meant to include situations in which the composition warms to greater than room temperature by the heat produced by polymerization. For the purposes of the present invention, "without the use of heat" is also meant to include situations in which the composition is polymerized at an elevated temperature (i.e., greater than room temperature) , so long as the rate of polymerization of the composition at such elevated temperature is not significantly greater (i.e., less than 10% greater) than the rate of the composition's polymerization at room temperature. For the purposes of the present invention, "without the use of light" is meant to include situations in which the composition is exposed to light, such as ambient lighting conditions, so long as the rate of polymerization of the composition when so exposed to light is not significantly greater (i.e., less than 10% greater) than the rate of the composition's polymerization in the complete absence of light. Further, "polymerization . . . without the use of heat" and "polymerization . . . without the use of light" does not refer to post -curing steps. Post curing steps, as used herein, refer to those steps carried out after the composition is sufficiently polymerized to be handled or, where appropriate, demolded (e.g., typically, after from about 50% to about 90% of the reactive acid (i.e., the carboxylic acid terminated fluoropolyether) and epoxy groups in the composition have reacted) . As will be explained.in greater detail below, polymerization can be effected "without the use of heat" and "without the use of light" and subsequently followed with a post cure step which involves the use of heat or light or both.

Typically, polymerization without the use of heat and without the use of light is carried out over a period of from about a few hours to about a few days . Usually, polymerization can be effected in about one day. Alternatively, the compositions of the present invention can be polymerized using heat or light or both. Typically, when light is used, the light is ultraviolet and a photoinitiator is included in the composition. Although, as one skilled in the art will note, the amount of exposure needed will depend on a variety of factors, suitable exposures for polymerizing the compositions of the present invention range from about 0.4 to about 80 Joules per square centimeter, typically from about 2 to about 10 Joules per square centimeter. Still alternatively, the composition of the present invention can be polymerized without the use of heat and without the use of light and then post-cured using heat or light or both. Post curing is particularly advantageous when materials having higher Tg's and improved long term stability are desired. For example, post curing can be carried out by heating the polymerized composition at from about 100 °C to about 250 °C for from about 1 minute to about 5 hours, preferably for from about 15 minutes to about 2 hours. Thermal post curing can also be carried out on compositions which have been polymerized using light.

As indicated above, the compositions of the present invention, when polymerized, are particularly useful in systems that transmit optical signals. In particular, they can be used i -an optical system to join together two or more optical components thereof. For example, in one embodiment of this aspect of the present invention, the optical system includes a first component and a second optical component and, disposed therebetween, a material prepared by polymerizing a composition according to the present invention, as described above. Illustrative optical components that can be joined in this fashion are two optical fibers, two waveguides, and an optical fiber and a waveguide. As one skilled in the art will recognize, optimization of this system would require that the indices of refraction of the two optical components being joined be substantially the same, so as to minimize reflection at the joint. Further, optimization would require that the composition be formulated so that its polymerization product would have substantially the same refractive index as the components being joined. As indicated above, the refractive index of the composition can be generally controlled by adjusting, 17 for example, the amount of chlorinated anhydride in the composition. In addition, as one skilled in the art would further appreciate, optimization of a process using adhesive to join optical components, such as two optical fibers, requires that the components be substantially aligned along their axes, so that signal passing through one fiber, for example, completely enters the second fiber. Methods for aligning optical components, particularly optical fibers, are well known in the art. For example, a device similar to the one used in the

Norland self-aligning UV curable splice system (see, e.g., U.S. Patent No. 4,960,316 to Berkey, which is hereby incorporated by reference) and the Lightlinker fiber optic splice system (see, e.g., U.S. Patent No. 4,889,405 to Walker et al . and U.S. Patent No. 4,506,946 to Hodge, which are hereby incorporated .by_ reference) . These splices include a central glass alignment guide composed of four tiny glass rods which have been fused together to provide a hollow core containing four V-grooves at the fused tangential points. The ends of the guide are bent somewhat along the longitudinal axis. This forms a fiber deflecting elbow on either side of a straight central portion of the guide. When fibers are inserted into the guide, the upward or downward slope of the ends forces the fibers to orient themselves in the uppermost or lowermost V-grooves of the guide, respectively. When the fibers meet at the center portion, they are both tangent to the guide surfaces so that the ends thereof abut each other. The splice is used by first filling the central opening with a composition of the present invention. After the fibers are prepared by stripping any exterior resin coating and squaring of the ends, they are inserted into the splice so as to be aligned when they contact each other. The composition of the present invention is then allowed to polymerize or is polymerized by exposing the composition to light (e.g., UV light) as discussed above, thus encapsulating the fiber and providing handling strength. Other methods for aligning optical fibers for splicing are described in, for example U.S. Patent No. 5,042,902 to Huebscher et al . and U.S. Patent No. 4,690,316 to Berkey, which are hereby incorporated by reference .

Optical waveguides or other optical fibers that are suitable for use in the optical systems of the present invention can be made by conventional methods, such as those set forth in U.S. Patent Nos . 3,659,915 and 3,884,550 to Maurer et al . ; U.S. Patent Nos. 3,711,262, 3,737,292, and 3,775,075 to Keck et al . ; U.S. Patent No. 3,737,293 to Maurer; U.S. Patent No. 3,806,570 to

Flamenbaum et al . ; U.S. Patent. No. 3,859,073 to Schultz, each of which is hereby incorporated by reference.

The present invention is further illustrated by the following non-limitative examples.

EXAMPLES

Example 1 -- Room Temperature and Anhydride Cure Compositions

Three compositions, denoted Sample 2, Sample 5, and Sample 6, were prepared using ERL-4221 (3,4- epoxycyclohexylmethyl-3 , 4-epoxycyclohexane carboxylate from Union Carbide, Inc.), Fluorolink C (a carboxylic acid terminated perfluoropolyethers from Ausimount Inc.), a 40:60 (w/w) mixture of chlorendic anhydride ("CA") and hexahydrophthalic anhydride ("HHPA"), and zinc octoate. The compositions were allowed to polymerize at room temperature for 24 hours and then post-cured at 150°C for 15 minutes, at 150°C for 15 minutes followed by 200°C for 15 minutes, at 150°C for 1 hour, and/or at 200°C for 15 minutes. The weights of the various components in each of Samples 2, 5, and 6 and the Tg (measured by dynamic mechanical analysis ("DMA")) and modulus (at 25°C) are reported in Table 1, below.

Table 1

Sample 2 Sample 5 Sample 6

ERL-4221 (wt%) 71.4 60 54.5

Fluorolink C 28.6 27.3 30.5

CA/HHPA (40:60) ( t%) 0 12.7 14.5 zinc octoate (wt%) 0 0 0.5

RT/24 hours

DMA Tg (DC) -48.6 &. -14 modulus (at 25DC) 2.7 x 10⁶ pa

150DC/15 minutes

DMA Tg (DC) 25 54 modulus (at 25DC) 3.7 x 10⁷ pa 6.4 x 10⁸ pa

150DC/15 minutes + 200nc/15 minutes

DMA Tg (DC) 78.9 59 modulus (at 25_C) 1.6 x 10⁷ pa 1 x 10⁹ pa

150__C/1 hour

DMA Tg (DC) -16 53.6 84 modulus (at 25DC) 3 x 10⁶ 3.47 x 10⁸ pa 1.61 x 10⁹ pa

200DC/15 minutes

DMA Tg (DC) 38.1 65 modulus (at 25IC) -2 x 10⁸ pa 9.4 x 10⁸ pa Example 2 -- UV Curable Compositions

Three compositions, denoted Sample 1, Sample 3, and Sample 7, were prepared using ERL-4221, Fluorolink C, CDIOIO (a cationic photoinitiator from Sartomer) , and PC- 1000 (a non-cycloaliphatic epoxy derivative resin available from Polyset Comapny, Inc. (Mechanicsville, New York) under the tradename Polyset PC-1000) . The compositions were exposed to two passes of ultraviolet light at an intensity of 4.0 J/cm² and then post-cured at

150°C for 1 hour. The weights of the various components in each of Samples 1, 3, and 7 and the Tg (measured by DMA) and modulus (at 25°C) are reported in Table 2, below.

Table 2

Sample 1 Sample 3 Sample 7

ERL-4221 ( t%) 69.7 34.6 84.6

Fluorolink C 29.9 30.3 14.9 CDIOIO ( t%) 0.5 0.5 0.5 PC-1000 (wt%) 0 34.6 0

UV-2 passes at 4.0 J/cm²

DMA Tg (°C) 101 & 168 34 168

modulus (at 25°C) 1.2 x 10⁹ pa -2 x 10⁸ pa 2.4 x 10⁹ pa

UV + 150°C/1 hour

DMA Tg (°C) 197.8 98.6 223.2

modulus (at 25°C) 1.6 x 10⁹ pa 1 x 10⁹ pa 2.4 x 10⁹ pa

Although the invention has been described in detail for the purpose of illustration, it is understood that such detail is solely for that purpose, and variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention which is defined by the following claims.

Claims

WHAT IS CLAIMED:

1. A composition comprising: a carboxylic acid terminated fluoropolyether; and a cycloaliphatic epoxy resin.

2. A composition according to claim 1, wherein said cycloaliphatic epoxy resin is a cycloaliphatic polyepoxy resin.

3. A composition according to claim 1, wherein said cycloaliphatic epoxy resin is selected from the group consisting of a 3 , 4-epoxycyclohexylmethyl- 3, 4 -epoxy cyclohexane carboxylate; a bis (3 , 4-epoxycyclohexylmethyl).adipate; a

3 , 4-epoxy-6-methylcyclohexylmethyl a

3 , 4 -epoxy-6-methylcyclohexane carboxylate; a bis (3 , 4 -epoxy- 6 -methyleyelohexylmethyl) adipate; a bis (2 , 3-epoxycyclopentyl) ether; a dipentene dioxide; a 2- (3 , 4-epoxycyclohexyl-5 , 5-spiro-3-4-epoxy) cyclohexane-metadioxane; and a cycloaliphatic diglycidyl ester epoxy resin.

4. A composition according to claim 1, wherein said cycloaliphatic epoxy resin is a 3 , 4-epoxycyclohexylmethyl -3 , 4 -epoxy cyclohexane carboxylate .

5. A composition according to claim 1, wherein said carboxylic acid terminated fluoropolyether is a carboxylic acid terminated perfluoropolyether .

6. A composition according to claim 1, wherein said carboxylic acid terminated fluoropolyether is a carboxylic acid terminated perfluoropolyether having a molecular weight of from about 300 to about 5000.

7. A composition according to claim 1 further comprising : a non-cycloaliphatic epoxy monomer or oligomer.

8. A composition according to claim 1 further comprising : a photoinitiator.

9. A composition according to claim 1 further comprising: a curing agent .

10. A composition according to claim 1 further comprising: an anhydride .

11. A composition according to claim 10, wherein said anhydride is a chlorine-containing anhydride.

12. A composition according to claim 10, wherein said anhydride is chlorendic anhydride.

13. A composition according to claim 10 further comprising: a second anhydride.

14. A composition according to claim 13, wherein said first anhydride is chlorendic anhydride and wherein said second anhydride is hexahydrophthalic anhydride .

15. A composition according to claim 14, wherein the chlorendic anhydride and hexahydrophthalic anhydride are present as a eutectic mixture.

16. A composition according to claim 14, wherein the chlorendic anhydride and hexahydrophthalic anhydride are present in a weight ratio of 40:60.

17. A composition according to claim 1, wherein said composition is substantially free of photoinitiators.

18. A composition according to claim 1, wherein said composition is substantially free of thermal initiators .

19. A composition according to claim 1, wherein said composition is substantially free of photoinitiators and thermal initiators.

20. An object comprising a polymerization product of a composition according to claim 1.

21. A material prepared by a method comprising: providing a composition according to claim 1 and polymerizing the composition.

22. A material according to claim 21, wherein said polymerizing step is carried out without the use of light.