JPH0648322B2 - Coated optical fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to coated optical fibers. The invention particularly relates to a method of coating an optical fiber with an ultraviolet curable silicone composition to form a flexible, low adhesion coating.

BACKGROUND OF THE INVENTION In the currently developing field of optical telecommunications, light is used to transmit information through transparent media in a manner similar to electricity through copper or aluminum wires. Since the information carrying capacity of electromagnetic radiation increases with frequency, the amount of communication that can be handled in the visible radiation (light) band is potentially several thousand times that of wireless communication.

Since the discovery of suitable light sources for lasers around 1960, the only technical impediment to telecommunications has been the development of suitable transmission media. For example, air is permeable to light, but was unsuitable because rain, fog, and other atmospheric conditions dilute (ie, "attenuate") the light signal. The development of glass fiber optical conductors, or optical fibers, has resulted in excellent transmission media that are relatively inexpensive.

Modern optical fibers are typically constructed by covering a core of highly transparent silica glass that transmits light with a transparent coating having a lower refractive index than the core. The coating acts as an internal mirror and reflects light back into the core, thus preventing the optical signal from being lost out of the optical path.

Although the theory of low refractive index coatings has yielded practical light guides for relatively short distance communications (eg, building-to-building and in-school), long-distance communications (eg, continents) that bundle multiple light guides together. Cross-section), the problem of signal "noise" becomes more important than signal attenuation. For a weak information carrier, any associated lightwave (carrying other information) or signal that disturbs the main lightwave from which the required information must be extracted becomes "noise".

Therefore, research continues to look for coating materials with higher or lower refractive indices than core fiber materials. For silica glass optical fibers, the reference point is 1.47, the index of refraction of the silica glass fibers.

When manufacturing fiber optic cables for telecommunications, the material used for the primary coating is very flexible, does not adhere too closely to the glass fiber core (to allow splicing and other operations), and Its integrity and optical properties must be maintained under varying environments including temperature cycling from -60 ° C to + 80 ° C.

Many optical fiber manufacturers have adopted coating compositions as the primary light guide coating. Typically, uncoated optical fiber is pulled through a silicone composition and then passed through an 800 inch curing 8 inch oven. The time required to completely cure the silicone composition is the limiting factor in increasing the line speed in making optical fibers. Increasing the oven temperature or increasing the oven length will oxidize the silicone and affect the fiber being pulled, thus increasing the line speed above about 30 m / min with commercially available thermoset silicone coatings. I can't.

With the desire to increase the production rate even faster, optical fiber manufacturers have set out to research ultraviolet (UV) curable materials. However, no coating composition has yet been found with a combination of properties comparable to the silicone materials mentioned above.

The inventor has discovered that certain UV curable polysiloxane compositions provide new coating materials for optical fibers that exhibit desirable combinatorial properties for optical fiber coating layers. Both low and high refractive index compositions have been found, all of which cure rapidly with a short exposure to UV light and thus are safer than thermoset silicone materials,
There are significant advantages in terms of cure speed and cost.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a fast setting composition that replaces the thermosetting polydimethylsiloxane composition for the primary coating layer of an optical fiber.

Another object of the present invention is to provide a coating material for optical fibers which can be coated simply and safely and which can be cured with short exposure to UV light.

Another object of the present invention is to provide new low refractive index coating compositions and high refractive index coating compositions.

Still another object of the present invention is to manufacture efficiently and cheaply,
An object of the present invention is to provide a coated optical fiber applicable to various lightwave telecommunications applications.

Yet another object of the present invention is to provide a cured coating that is flexible and does not adhere tightly to the core fiber and that can withstand large changes in environmental conditions, while increasing the speed of production lines. It is to provide a method of coating a primary coating on a fiber core.

A UV-curable coating composition that achieves the above objects and other objects is (A) a formula RR'SiO (wherein R is hydrogen or a monovalent hydrocarbon group having 1 to 8 carbon atoms, and R'is Hydrogen, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent organic group having 2 to 20 carbon atoms having epoxy or vinyl functionality).
(B) Contains a catalytic amount of photoinitiator.

In the present invention, (A) a highly transparent silica glass core, and (B) the core is coated, and (i) the formula RR′SiO (wherein R is hydrogen or a monovalent carbon atom having 1 to 8 carbon atoms). Is a hydrogen radical,
R'is hydrogen, a monovalent hydrocarbon group having 1 to 20 carbon atoms or 2 to 2 carbon atoms having epoxy or vinyl functionality.
A diorganopolysiloxane containing 20 units of monovalent organic groups) and (ii) a UV curable silicone coating composition containing a catalytic amount of a photoinitiator, the coating having a refractive index different from that of the silica glass. A coated optical fiber consisting of, is also considered.

According to still another aspect of the present invention, (1) (i) formula RR′SiO (wherein R is hydrogen or a monovalent hydrocarbon group having 1 to 8 carbon atoms, and R ′ is hydrogen or carbon). Diorganopolysiloxane containing units of 1 to 20 monovalent hydrocarbon radicals or 2 to 20 monovalent organic radicals having epoxy or vinyl functionality) and (ii)
A UV-curable silicone coating composition containing a catalytic amount of a photoinitiator is coated on a core fiber of highly transparent silica glass, and (2) the coated core fiber is exposed to UV light of sufficient intensity for a sufficient time to produce the above-mentioned product. A high-speed method for producing a coated optical fiber, which comprises a step of curing the coating composition on the core fiber to form an environmentally safe coating having a low flexibility and a low adhesiveness on the core fiber and having a low flexibility Provided.

Methods for effectively controlling the refractive index and viscosity of the polysiloxane coating materials disclosed herein are also contemplated.

For purposes of the present invention, the term "low adhesion" relates to the desired properties of the primary coating layer over the glass optical fiber,
It means that the coating layer does not adhere strongly to the core fiber so as to prevent the usual mechanical operations applied to the optical fiber, eg splicing. This term does not relate to the optical relationship between the core and the coating (primary coating) layer. In addition, the term "environmental safety"
Relates to the ability of the coating material of the present invention to maintain its integrity and optical properties through environmental changes normally experienced by the fiber, especially temperature changes between the upper and lower limits of about -60 ° C to + 80 ° C.

DETAILED DESCRIPTION OF THE INVENTION To produce the coated optical fiber of the present invention, UV curing
The curable epoxy-functional or vinyl-functional silicone coating composition is coated on transparent silica glass fiber which is then briefly exposed to UV light. The coated optical fiber of the present invention has all of the desirable properties found in fibers coated with thermoset polydimethylsiloxane, while at the same time increasing manufacturability, reducing energy consumption and ensuring UV cure safety.

Ultraviolet (UV) is one of the most widely used radiations because it is low in cost, easy to manage, and has little potential harm to industrial users. UV curable compositions not only exhibit extremely short cure times, but also avoid the high energy costs, environmental constraints and safety hazards associated with the use of thermosetting materials.

The UV curable composition used in the present invention basically comprises two components: (i) an epoxy functional or vinyl functional organopolysiloxane base polymer and (ii) rapid curing of the composition upon exposure to UV light. In combination with a photoinitiator capable of promoting

The epoxy functional organopolysiloxane based polymers contemplated by this invention consist of units having the general formula RR'SiO. Here, R is hydrogen or a monovalent hydrocarbon group having 1 to 8 carbon atoms, and R'is the same as R or a monovalent organic group having 2 to 20 carbon atoms and having epoxy functionality. The epoxysilicone polymer can have up to about 20% by weight of epoxy functional groups and must be capable of curing or crosslinking when exposed to UV light in combination with a suitable photoinitiator. The cured polymer composition must have a different index of refraction than the optical fiber core and must exhibit flexibility, low adhesion to the core fiber and environmental stability.

Suitable epoxy functional polydiorganosiloxanes contemplated by the present invention are more particularly dialkylepoxy chain-terminated polydialkylalkylepoxysiloxane copolymers in which the polysiloxane units contain lower alkyl substituents, especially methyl groups. To obtain epoxy functionality, some of the hydrogen atoms on the polysiloxane chain of the polydimethyl-methylhydrogen siloxane copolymer may have both ethylenic unsaturation and epoxide functionality in the hydrosilation addition reaction. React with the organic molecules of. The ethylenically unsaturated species is added to the polyhydroalkylsiloxane to form a functionalized polymer in the presence of a catalytic amount of a noble metal catalyst. Although such a reaction is a crosslinking mechanism for other silicone compositions, in the present invention it causes a controlled amount of crosslinking to the silicone precursor or intermediate fluid. This is called "pre-crosslinking". Pre-crosslinking of the silicone precursor fluid means that partial cross-linking or curing of the composition has occurred, which allows for fast UV-initiated curing with little energy consumption and no need for solvent. The advantage of doing so is given to the invention.

The UV curable epoxy functional silicone intermediate fluid consists of a pre-crosslinked epoxy functional dialkylepoxy chain-terminated polydialkyl-alkylepoxy silicone copolymer fluid, which has a vinyl or allyl functional epoxide and a viscosity of 25 ° C. A vinyl functional siloxane cross-linking fluid that is about 1 to 100,000 centipoise;
Accelerates the addition-curable hydrosilation reaction between a hydrogen functional siloxane precursor fluid having a viscosity of about 1 to 10000 centipoise at 25 ° C. and a vinyl functional crosslinking fluid, a vinyl functional epoxide and a hydrogen functional siloxane precursor fluid. Which is a reaction product reacted in the presence of an effective amount of a noble metal catalyst.

The unsaturated epoxides contemplated herein can be any of a number of aliphatic or cycloaliphatic epoxy compounds having an olefin component that readily undergoes an addition reaction with the ≡SiH functional group. Examples of such compounds include 1-methyl-4-isopropenylcyclohexene oxide (limonene oxide; manufactured by SCM Corp.), 2,6-dimethyl-2,3-epoxy-
7-octene (manufactured by SCM Corp.) and 1,4-dimethyl-4
-Vinylcyclohexene oxide (from Viking Chemical Co.). Limonene oxide is preferred.

Noble metal catalysts for hydrosilation reactions related to the present invention include
It can be selected from the group of platinum group metal complexes including complexes of ruthenium, rhodium, palladium, osmium, iridium and platinum.

Specific examples of hydrosilation catalysts suitable for this purpose include U.S. Pat. Nos. 3,220,972 (Lamoreaux), 3,715,334 (Karstedt), and 3,775.
452 (Karstedt) and 3814730 (Ka
rstedt).

In the present invention, the vinyl functional siloxane crosslinking fluid is a dimethylvinyl chain terminated linear polydimethylsiloxane, a dimethylvinyl chain terminated polydimethyl-methylvinylsiloxane copolymer, tetravinyltetramethylcyclotetrasiloxane and tetramethyldivinyldiene. It can be selected from the group consisting of siloxanes. The hydrogen-functional siloxane diprecursor fluid is selected from the group consisting of tetrahydrotetramethylcyclotetrasiloxane, dimethylhydrogen chain terminated linear polydimethylsiloxane, dimethylhydrogen chain terminated polydimethyl-methylhydrogen siloxane copolymer and tetramethyldihydrodisiloxane. can do.

Suitable photoinitiators for the epoxy functional base polymers of the present invention include those having the general formula: Iodonium salts having Where X is SbF ₆ ,
Selected from AsF ₆ , PF ₆ and BF ₄ , R ″ is 4 carbon atoms
To 20 monovalent alkyl or haloalkyl groups, n
Is an integer equal to 1-5. These compounds have U for epoxy functional polysiloxanes as disclosed in US Pat. No. 4,279,717 (Eckberg et al.).
It was confirmed to be extremely efficient in promoting the V-initiated cationic ring-opening curing mechanism.

Among the iodonium salt photoinitiators for use with the epoxy functional silicones of the present invention, the diaryl iodonium salts derived from the "linear alkylate" dodecylbenzene are preferred. Such salts have the general formula: (X in the formula is SbF ₆ , AsF ₆ , PF ₆ or BF ₄ ). These bis (4-dodecylphenyl) iodonium salts are extremely effective initiators for UV curing of a wide range of epoxy functional silicones.

"Linear alkylate" dodecylbenzene is well known in the industry and is prepared by the Friedel-Crafts alkylation reaction of benzene with a C _(11-13) α-olefin fraction. As a result, the alkylate contains a predominant amount of branched-chain dodecylbenzene, but in fact other isomers of dodecylbenzene, such as ethyldecylbenzene and isomers of uredecylbenzene, tridecylbenzene, etc. Exists in large quantities. However, such a mixture contributes to the dispersive nature of the linear alkylate-derived catalyst and helps keep the material in the fluid. These catalysts are viscous fluids that are free flowing at room temperature. The preferred bis (dodecylphenyl) iodonium salt is alkane soluble and water insoluble and is well dispersed in the preferred epoxy functional polysiloxanes used in the coating compositions of the present invention. Most preferred are bis (4-n-tridecylphenyl) iodonium hexafluoroantimonate and bis (4-n-dodecylphenyl) iodonium hexafluoroantimonate.

Vinyl functional base polymers contemplated by the present invention include:
In effect, it is a photoreactive terpolymer that is curable when exposed to UV radiation in the presence of certain radical photoinitiators. The terpolymer is a dimethylvinyl-terminated and trimethyl-terminated linear polydimethyl-methylvinyl-methylhydrogensiloxane terpolymer mixed fluid, which includes polymethylhydrogensiloxane fluid, tetramethyltetravinylcyclotetrasiloxane (methylvinyltetramer) and octamethylcyclohexyl. It can be synthesized by an acid equilibration reaction of tetrasiloxane (dimethyltetramer).

These vinyl functional terpolymers have two or more benzene rings that can be fused or bridged by organic or hetero groups such as oxa, thio and the like. It is curable in the presence of polyaromatic photosensitizers. Among these photosensitizers, benzophenone and t-butylanthraquinone are preferable.

Terpolymers can also be cured in the presence of certain bellbenzoate esters (perbenzoates) having the general formula:

Wherein R ³ is a monovalent alkyl or aryl group,
Are hydrogen, alkoxy, alkyl, halogen, nitro, amino, primary and secondary amino, amide and the like. The nature of Z affects the stability of the peroxy bond, electron deficient substituents stabilize the peroxy bond, while electron rich substituents make the peroxy bond more reactive. Suitable perbenzoate esters include t-butyl perbenzoate and its rose substituted derivatives such as t-butyl per-p-nitrobenzoate, t-butyl per-p-methoxybenzoate, t-butyl per-p-methyl benzoate and t-butyl per ester. -P-chlorobenzoate.
The photoreactive polysiloxane terpolymers of the present invention and the photoinitiators effectively used therewith are filed in US patent application 527 filed on the same date as the US application corresponding to this application.
299.

The amount of photoinitiator used is not critical as long as proper curing is achieved. As with all catalysts, it is preferred to use the minimum effective amount. However, for purposes of illustration, it has been determined that catalyst levels of about 1-5% by weight are suitable for the compounds described above. Combinations of photoinitiators can also be used.

The epoxy-functional and vinyl-functional polysiloxanes described above typically have a low refractive index, ie, below 1.47, when the non-epoxy or non-vinyl substituents along the siloxane polymer chain are hydrogen or lower alkyl. Has a refractive index. The refractive index of polysiloxane can be increased by compositionally blending a polymer that also contains diphenylsiloxy units.

As mentioned above, epoxy-functional polydiorganosiloxanes can be obtained by reacting vinyl-functional epoxides with SiH-containing polydiorganosiloxanes, such as polydimethyl-methylhydrogensiloxane copolymers. To obtain a relatively high refractive index, diphenylsiloxy-containing and SiH-containing polysiloxanes can be synthesized by cohydrolysis of diphenyldichlorosilane, dimethyldichlorosilane and methylhydrogendichlorosilane. It can be reacted with vinyl functional epoxides to impart epoxy functionality to the polymer. However, a small amount of acid residue, which is difficult to remove by stirring into such a linear high-phenyl SiH polymer, acts to cleave the oxirane ring of the epoxide, resulting in a non-photoreactive polysiloxane. Another difficulty of this method is that in order to raise the refractive index to 1.50 or higher, the polymer must contain 30 mol% or more (50 wt% or more) of diphenylsiloxy units. Makes siloxane very expensive.

In a preferred embodiment of the present invention, the SiH containing polysiloxane is used to prepare a composition having a high refractive index, wherein the SiH containing polysiloxane is a vinyl functional aromatic compound having 1 to 20 carbon atoms (to obtain an aromatic substituent on the chain. A) and a vinyl functional epoxide (to obtain epoxy functional substitution).

Vinyl-functional aromatic compounds contain at least one aromatic ring and undergo Si addition via a hydrosilation addition reaction.
It contains at least one aliphatic unsaturated site capable of reacting with the H group to form a carbon-silicon bond. Ethenylbenzene (ie styrene) is most preferred, but
Many other vinyl aromatic compounds will be apparent to those skilled in the art, and these are also included in the above compounds.

In the reaction with the SiH-containing polysiloxane, the vinyl aromatic compound and the unsaturated epoxide can be introduced at the same time (competing for the hydride reaction position) or, preferably, they can be introduced sequentially. The epoxy functionality and refractive index of the final product can be well controlled.
Since increasing the refractive index of the composition is the primary purpose of using such vinyl aromatic compounds, it is most preferred to react the vinyl aromatic compound first and then add the epoxy functionality. The exact relative amounts of the vinyl aromatic compound and vinyl functional epoxide used can vary within wide limits depending on the desired refractive index and the desired reactivity. With the proper choice of reactants, their amounts, and reaction conditions, high refractive index epoxy functional silicones can be produced tailored to specific needs.

From this point of view, it is better to carry out a simple experiment on the reaction parameters.

Combinations of iodonium salt photoinitiators with other known photoinitiators are also contemplated. Among such catalyst blends, the combination of iodonium salts and free radical photoinitiators, such as acetophenone derivatives, is preferred. Most preferred is an equal (1: 1) blend of diaryliodonium salt and diethoxyacetophenone.

The UV-curable silicone coating composition of the present invention is coated on an optical fiber by a method well known in the art. For example, in a typical example, an uncoated optical fiber is passed through a coating solution, then placed on a line and pulled through a curing chamber. As mentioned above, the curing process has heretofore been the limiting cause of the speed at which the coating operation can be carried out. Providing a flexible, low adhesion, environmentally stable primary coating on a silica glass core fiber by using an epoxy functional silicone coating composition that is curable with short exposure to UV light in accordance with the present invention. In addition, the coating can be applied at high line speeds without exposing the coating material or fibers to the high temperatures of the furnace.

It has been found that the viscosity of the coating composition is an additional property that optical fiber manufacturers must consider as the compositions of the present invention allow for increased line speeds (see Examples 1 to 1 below). 3). Generally, at high production speeds, viscosities of less than about 1000 cps "wet" the fiber.
It turns out that (that is, covering) is impossible. About 10,0
At viscosities higher than 00 cps, air bubbles will be entrained in the coating, causing defects in the primary coating that cause signal attenuation.

In the case of epoxy-functional silicones produced via the hydrosilation addition reaction of vinyl-functional epoxides to SiH-containing polysiloxanes, the viscosity of the final product depends not only on the viscosity of the SiH-containing precursor but also on the degree of epoxy functionality. Is also dependent, so it is difficult to predict. For example, a 90 cps precursor fluid containing 10 wt% methyl hydrogen siloxy units will be converted to an epoxy functional silicone containing 18 wt% limonene oxide resulting in a viscosity of about 400 cps containing 10 wt% methyl hydrogen siloxy units. The 200 cps precursor fluid is converted to an epoxy functional silicone with a viscosity of 3,000 cps. Then, when 11.7% by weight of limonene oxide is introduced into a 200 cps precursor fluid containing 6% by weight of methyl hydrogen siloxy units, the viscosity becomes 1000 cps.

Simultaneous addition of vinyl MQ silicone resin and vinyl functional epoxide to a given SiH containing polysiloxane results in
It has been found that a product is obtained whose viscosity depends on the resin content. The vinyl MQ resins considered herein are primarily polysiloxanes having monofunctional (M) or tetrafunctional (Q) units. The vinyl group of this resin competes with the vinyl functional epoxide for available hydride positions in the polysiloxane. The resin is thus incorporated into the epoxy functional polysiloxane product.

Vinyl MQ resins are M units having the formula Y ₃ SiO _1/2 and the formula SiO
It is composed of Q units having _4/2 and the ratio of M to Q units is approximately 0.5 to 1.0, preferably about 0.65. Each Y group independently represents the same or different monovalent hydrocarbon group having 2 or less carbon atoms, and at least one Y group must be vinyl. Such groups include, for example, methyl, ethyl,
There are vinyl or ethynyl. Methyl and vinyl are preferred. A general description of these resins is given by Noll in "Che
MISRY AND TECHNOLOGY OF
Silicones "(2nd edition, 1968), chapters 1 and 6.

In an embodiment of the present invention utilizing the above findings, the final UV-curable polysiloxane product contains side chain siloxy groups corresponding to the introduced MQ resin. In the case of these polysiloxanes, the definition of the R'group in the above formula is
1 to 200 Q siloxy units of O _4/2 and formula Y ₃ SiO
It is extended to include branched organosiloxane groups consisting of _1/2 (wherein Y is a monovalent hydrocarbon group having 1-2 carbon atoms) M siloxy units. The terms "diorganopolysiloxane" and "organopolysiloxane-based polymer" used herein to describe the epoxy and vinyl functional polymer products of the present invention.
Is a sufficiently broad term to also include such branched polysiloxane side groups.

If a high refractive index material is desired, an aromatic glycidyl ether is used as a reactive diluent as an alternative to changing the viscosity of the coating composition-also introducing an index-increasing aromatic group into the system. The aromatic glycidyl ether reactive dilutability also adds epoxy functionality and thus improves the curing properties of the coating composition of the present invention. This is described in US Patent Application No. 375676 (filed May 6, 1982).
As found for silicone paper release compositions with added epoxy polymer.

In order that those skilled in the art may better understand the practice of the present invention, the following examples are given by way of illustration and not limitation.

Examples 1-3 Three epoxy functional silicone coating compositions were prepared as follows for optical fiber coating experiments.

Sample 15 5 parts by weight of 250 cps dimethyl vinyl chain terminated polydimethylsiloxane fluid, 320 parts by weight of limonene oxide, and 1 part by weight of platinum catalyst (platinum-octyl alcohol complex) were added to 1,000 parts by weight of toluene. 1,000 parts by weight of 15 parts of this mixture was stirred at room temperature.
0 cps dimethyl hydrogen chain terminated polydimethyl-methyl hydrogen siloxane copolymer fluid (containing about 8.7 wt% ≡SiH) was added slowly over 1 hour. The reaction mixture was then refluxed at 120 ° C. for 21 hours, at 21 hours 30 parts by weight of n-hexene were added and reflux was continued for another 4 hours. Stripping the solvent under vacuum at 130 ° C
1,00 containing about 17.2% by weight of limonene oxide groups
A 0 cps limonene oxide functional polysiloxane fluid was obtained.

Samples 2 and 3 Two more limonene oxide functional products were prepared as Sample 2 and Sample 3, following the same procedure as for Sample 1 above. Sample 2 was a 680 cps fluid containing about 14.0 wt% limonene oxide groups and Sample 3 was a 700 cps fluid containing about 11.7 wt% limonene oxide groups.

All three compositions were combined with 1.5 wt% bis (dodecylphenyl) iodonium hexafluoroantimonate cationic photoinitiator.

Each coating composition was coated on 10 mil diameter pure silica glass fiber immediately after its drawing. The coating equipment was a 0.025 inch orifice attached to the bottom of a small cup. The coating was performed by pulling the drawn optical fiber downward into the test composition and then pulling through an orifice to adjust the coating thickness. Immediately pass the coated fiber through a nitrogen inerted cure chamber where one focusing 300 watt, 10 inch long Fusion SY Systems
Exposed to "H" UV lamp. The coated fiber was finally wound on a take-up roll.

The coated fiber was observed to see if the coating was fully cured. The line speed was gradually increased in order to determine the line speed at which the coating on the fiber did not cure completely, i.e. to find a point where the line speed exceeded the cure rate.

For each sample examined, the coating composition was fully cured at line speeds that exceeded the coating speed. In other words, the "wetting" (ie, coating) of the optical fiber with the silicone fluid ended at the line speed at which full cure was still observed. Complete cure was observed under the following conditions for the three sample compositions.

These results are advantageous compared to the maximum line speed of about 30 m / min observed with commercial thermoset silicone systems.

Examples 4-7 60 cps containing 10% by weight of methyl hydrogen siloxy units.
600 parts by weight of the linear dimethyl hydrogen chain-stopped polydimethyl-methylhydrogensiloxane fluid of s were dissolved in 600 parts by weight of hexane. To this solution (containing 1.0 mol of active SiH groups), 152 parts by weight of limonene oxide (1 mol),
About 25 ppm platinum in the form of a soluble complex catalyst and various levels of vinyl MQ silicone resin were added. The reaction mixture was refluxed for 4 hours, after which unreacted SiH was removed by reaction with hexene. The solvent, unreacted limonene oxide and hexane were stripped under vacuum to give the epoxy functional polymer below.

100 parts by weight of each sample were added with 1.5 parts by weight of diethyl acetophenone and 1.5 parts by weight of (C ₁₂ H ₂₅ Ph) ₂ ISbF ₆ (epoxy functionality as disclosed in the aforementioned US patent application No. 375,676). Curing was evaluated by blending with a free radical / cationic cocatalyst system for curing silicones.
The complete coating composition was manually applied as a 2 mil coating on polyethylene kraft paper using an adhesive coater to remove PPG.
Exposed to two focusing medium pressure mercury vapor UV lamps fitted to the 1202 UV processor. The cure was qualitatively evaluated by varying the conveyor speed (exposure time), UV intensity and cure environment. The following results were obtained.

By comparison with the control composition (Sample 4), the introduction of the vinyl MQ resin results in a significant qualitative difference in cure, provided that the composition of the epoxy-functional silicone composition is within the specified target viscosity range. I know there isn't.

Example 8 10000 with introduction of 11.3% by weight of limonene oxide
90 parts by weight of cps epoxy-functional polysiloxane 1,2-
Epoxy dodecane (Vikolox 12, Viking Chemical C
o.) Blended with 10 parts by weight of 4200 cps
Got The cocatalyst of Examples 4-7 was added to complete the composition.
In the same manner as in Examples 1-3 above, a 6 mil optical fiber is used.
Coating was carried out at a pulling speed of up to 0 m / min. 60m / min speed
Coating becomes too thin (less than 80 microns)
Since the fibers entering are very hot, the coating composition
Pyrolysis (smoke) was obvious. However, the film is
Even once cured with exposure to a 300 watt UV lamp. This
From these results, with the composition of the present invention, optical fiber
It is possible to double the production speed of the bar with an appropriate composition.
I understand. Further, the above-mentioned US Patent Application No. 375.676.
And a reactive diluent for accelerating cure, as disclosed in
Suitable ω-epoxy C_(8-11)Aliphatic hydrocarbon
As a viscosity modifier for the optical fiber coating composition of the present invention
It is clear from this example that it is useful.

Examples 9-12 75 parts by weight of linear trimethyl chain terminated polydimethyl-methylhydrogensiloxy fluid of 75 cps having 44.9% by weight methylhydrogensiloxy units (1.5 moles of active SiH groups) and 126 parts by weight of styrene (1. 27 mol) together with hexene 40
It was dispersed in 0 parts by weight. When 0.35 part by weight of platinum catalyst was added and the reaction mixture was stirred and heated slowly to 60 ° C, an exothermic reaction occurred at this point, the temperature was raised to 75 ° C, and then the temperature was lowered to around 65 ° C, where the reaction The mixture was maintained for 1 hour. Infrared analysis measured 0.23 moles of unreacted SiH, indicating that the styrene addition was almost complete. Then 60 parts by weight (0.4 mol) of limonene oxide were added and the reaction mixture was brought back to 69 ° C. and kept at this temperature for 64 hours with stirring. The product showed only 0.007 mol of unreacted SiH, which was removed in a short reaction with hexene. The solvent and unreacted monomer were stripped to give a viscous liquid product (11.680 cps) with a refractive index of 1.492. This fluid, designated Sample 9, contained 33.0% by weight styrene and 13.
1% by weight of limonene oxide had been introduced. The other 3
Seed compositions were prepared in a similar manner with the following results.

The above polymer and cresyl glycidyl ether (DY O23, Ci
ba Geigy) to obtain the following composition.

The UV-curing properties of the above β-phenethyl and limonene oxide substituted polysiloxane fluid were determined by adding 4% by weight of a 1: 1 blend of diethoxyacetophenone and (C ₁₂ H ₂₅ Ph) ₂ ISbF ₆ and adding the catalyst containing mixture to a polyethylene kraft group. The material was coated and then qualitatively examined by exposing the coated substrate to UV light as previously described.

The following results were obtained.

It was found that the diaryl salt catalyst was much more soluble in the β-phenethyl epoxy functional silicone, even with the lower refractive index epoxy functional silicones described in the previous examples. This means that curing can be done faster by increasing the catalyst concentration if necessary. Moreover, it is clear that the presence of the β-phenethyl substituent results in faster cure at lower epoxy loadings, and it is clear that the ether blends described above cure equally well in air or an inert atmosphere. This makes the high refractive index composition a very efficient coating composition.

If a large amount of cresyl glycidyl ether such as 25% is present, the curing rate can be kept high. Other aromatic epoxy monomers such as bisphenol A diglycidyl ether and epoxy novolac resins are expected to be compatible with epoxy functional silicones as well.

Example 13 A low refractive index (1.43 or less) polysiloxane composition was prepared as follows.

60 parts by weight of trimethyl chain terminated polydimethylmethyl water
Elemental siloxane fluid (25 cps), 84 parts by weight sym-tet
Lamethyltetravinylcyclotetrasiloxane and 1
056 parts by weight of octamethylcyclotetrasiloxane
6 parts by weight Filtrol 20 Nitrogen in the presence of acid equilibration reaction catalyst
The mixture was stirred at 100 ° C. for 17 hours in an elementary atmosphere. 6 parts by weight
MgO is added to neutralize the acid and the mixture is brought to 100 ° C. once more.
Hold for a while, and then neutralize the reaction product under reduced pressure of 48 mmHg.
Stripped at 165 ° C for 2 hours. 829 parts by weight
Treating the fluid product with 20.8 parts by weight of benzophenone,
Stir at 70 ° C for 75 minutes, then cool to below 50 ° C
It was Add 40 parts by weight of t-butyl berbenzoate,
Stir the entire mixture for 10 minutes, then solidify by filtration.
Filtrol And MgO are removed, and fluid generation of 1800 cps
I got a product.

The composition was applied to polyethylene kraft paper to a thickness of 2 mils and then the total power applied to the PPG1202 processor was 40 watts.
Exposed to a 0 watt UV lamp. Curing at various line speeds gave the following results.

The same composition was coated onto a 10 mil diameter optical fiber as described above and then cured by exposure to one 300 watt "H" lamp (Fusion Systems) in an inert atmosphere. The fiber wets the coating material well up to a pull rate of about 35 m / min. A well cured, 140 micron thick coating was obtained. At higher speeds, the coating material appeared to cure completely at speeds of 40 m / min and above, but the coating thickness decreased rapidly.

High refractive index vinyl functional polymers that are UV curable in the presence of a bell benzoate catalyst are prepared according to the disclosure herein with four different units such as methyl vinyl-, diphenyl-, dimethyl- and methyl hydrogen-siloxy. It is expected that it can be manufactured from the unit.

Example 14 300 parts by weight (2.88 mol) of styrene were added to 800 parts by weight of toluene and a platinum complex catalyst (to give a total mixture of 25 ppm platinum). The solution was heated to 80 ° C. at which point 69% by weight of methyl hydrogen siloxy units (total 4.6%).
400 parts by weight of a 21 cps trimethyl chain-terminated linear polydimethyl-methylhydrogensiloxane fluid with 1 mol SiH) were added slowly over a period of 4 hours while maintaining the reaction mixture at a temperature of 81-84 ° C. After stirring for 15 minutes, 289 parts by weight (1.9 moles) of limonene oxide were added and the reaction mixture was refluxed at 82 ° C. for 17 hours, then 9 minutes.
Refluxed at 0 ° C. for 22 hours. At this point, the unreacted SiH-containing unit had fallen to about 2.4% by weight. Unreacted SiH was removed by reaction with hexene and the product was stripped under vacuum at 140 ° C for 40 minutes to give 880 parts by weight of 18,800 cps.
A fluid is obtained. Assuming styrene was added quantitatively, this product, designated Sample 14, contained 31.9% by weight.
Of styrene and 25.4% by weight of limonene oxide. The refractive index of this material was 1.503.

A coating composition of suitable viscosity was prepared by blending Sample 14 with various epoxy functional reactive diluents selected from the following.

DY023 (Ciba Geigy) ＝Cresyl glycidyl ether CY179 (Ciba Geigy) ＝EPON 825 (Shell Chemicals) ＝Diethoxyacetophenone and (C₁₂H_{twenty five}Ph)₂ISbF₆Add 1% blend of 5% by weight of catalyst
did. The outline of the composition is as follows.

The composition was coated onto a polyethylene kraft substrate to a coating thickness of 1 mil and then cured on a PPG QC 1202 AN processor as described above. The curing performance record is as follows.

Obviously, various changes and modifications of the present invention are possible in light of the above disclosure. For example, in the light of the examples, limonene dioxide (or other polyepoxide monomer) is expected to be an effective epoxy functional diluent for high refractive index epoxy functional polysiloxane compositions. Also, the epoxy-functional or vinyl-functional polysiloxane compositions described herein may be used, for example, in US patent application Ser. No. 375,676 (filed May 6, 1982) and US patents of this application assigned to the applicant. It may also be advantageous in certain circumstances to modify with additives to improve the curing properties, as disclosed in US patent application 527299, filed on the same date as the application. However, it should be understood that these and other additional modifications to the particular embodiments of the invention are also within the scope of the invention.

Continuation of the front page (56) Reference JP-A-54-47667 (JP, A) JP-A-58-30703 (JP, A) JP-A-55-41469 (JP, A) JP-A-60-42711 (JP , A) Japanese Patent Publication Sho 57-30820 (JP, B2)

Claims (10)

[Claims] 1. A coated optical fiber comprising: (A) a core of highly transparent silica glass; and (B) a coating film coated on the core and having a refractive index different from that of the silica glass. A diorganopolysiloxane containing a plurality of RR'SiO units (R in each unit is hydrogen or 1 carbon atom)
~ 8 monovalent hydrocarbon group, R'of each unit is hydrogen,
Selected from the group consisting of monovalent hydrocarbon groups having 1 to 20 carbon atoms, monovalent organic groups having 2 to 20 carbon atoms having epoxy functionality, and branched organosiloxanes derived from vinyl MQ resins, R'is present in an amount sufficient to cause crosslinking due to the epoxy functionality, and the MQ resin allows the viscosity of the coating composition to depend on the MQ resin content,
R'is present in an amount sufficient to control the viscosity of the coating composition in the range of 1,000 cps to 10,000 cps. ), And (ii) a catalytic amount of an initiator, and a coated optical fiber comprising an ultraviolet-curable silicone coating composition. 2. The diorganopolysiloxane is epoxy-functional and the photoinitiator has the formula: (X in the formula is SbF ₆ , AsF ₆ , PF ₆ and BF ₄
R ″ is a monovalent alkyl or haloalkyl group having 4 to 20 carbon atoms, and n is 1 to 5
A coated optical fiber according to claim 1, which comprises a diaryl iodonium salt of an integer equal to 1) or a combination thereof with a free radical photoinitiator. 3. The coated optical fiber according to claim 2, wherein the diaryliodonium salt is a bis (dodecylphenyl) iodonium salt. 4. The coated optical fiber according to claim 2, wherein the photoinitiator comprises a combination of a bis (decylphenyl) iodonium salt and diethoxyacetophenone. 5. Coated optical fiber according to claim 2, wherein the diorganopolysiloxane has up to 20% by weight of epoxy functional groups. 6. The coated optical fiber according to claim 5, wherein the epoxy functional group is a limonene oxide group. 7. The diaryliodonium salt is bis (4
A coated optical fiber according to claim 5 selected from -n-tridecylphenyl) iodonium hexafluoroantimonate and bis (4-n-dodecylphenyl) iodonium hexafluoroantimonate. 8. The coating composition also contains, as component (iii), a reactive diluent selected from polyepoxide monomers and aromatic glycidyl ethers in an amount sufficient to reduce viscosity. A coated optical fiber according to claim 2. 9. The reactive diluent is limonene dioxide, The coated optical fiber according to claim 8, which is selected from the group consisting of: 10. The diorganopolysiloxane is mainly represented by the following formula: The coated optical fiber according to claim 2, which comprises the polymer unit of