Fluorinated crosslinker and composition

Details Fluorinated crosslinker and composition Fluorinated crosslinker and composition

2002-01-31

2004-02-10

Rotman, Alan L. (Department: 1625)

Organic compounds -- part of the class 532-570 series

Organic compounds

Carboxylic acid esters

Reexamination Certificate

active

06689900

ABSTRACT:

BACKGROUND OF THE INVENTION
The invention is directed to a class of fluorinated multifunctional alcohols and their derivatives such as acrylates and methacrylates, collectively referred to herein as acrylates, epoxies and vinyl ethers. The acrylates, epoxies and vinyl ethers are used as crosslinkers in compositions for optical coatings and waveguide devices.
Prior art references have disclosed that fluorine-containing polymers may be used for coating applications. See, for example, A. A. Wall, Fluoropolymers, Wiley-Interscience, 1972, and T. Deisenroth, Proc. Fluorine in Coatings II, Munich, 1997. The fluorinated polymers offer unique properties such as excellent chemical and thermal stability, good weathering and humidity resistance, low surface tension, low refractive index, and low absorption in the electromagnetic spectral region from 1300 to 1610 nm. The 1300-1610 nm region of the electromagnetic spectrum is particularly useful for fiber optic telecommunication networks. For example fluoropolymers have been used to coat optical fibers as well as to fabricate optical waveguides.
It is well known in the art that actinic radiation such as UV light permits fast curing. UV curable compositions containing fluorinated monomers, oligomers and polymers have been widely reported. See, for example, U.S. Pat. Nos. 4,508,916; 4,511,209; 4,914,171; 5,024,507; 5,062,680; 5,223,593; 5,822,489; 6,133,472; European patent No. 333,464A1; and publications including J. Pacansky, Progress in Organic Coatings, 18 (1990) 79 and R. Bongiovanni, Progress in Organic Coatings, 36 (1999) 70; all of which are herein incorporated by reference. These compositions comprise fluorinated mono- or multi-functional acrylates or vinyl ethers and at least one photoinitiator.
Most of the fluorinated acrylates disclosed in the prior art contain one or two acrylate groups per molecule. However, to achieve fast cure and high crosslinking density it is desirable that multifunctional crosslinkers having at least 3 functional groups per molecule are added to the formulations. Multifunctional hydrocarbon monomers such as acrylates, vinyl ethers and epoxies have been widely used as crosslinkers but their poor solubility in highly fluorinated monomers and polymers limits their applications in fluoro-coatings. Ausimont USA of Thorofare, N.J. provides Fluorolink T and T10, which have four hydroxyl groups per molecule. However two of the four hydroxyl groups are attached to secondary carbon atoms. As is well known to those skilled in the art, due to steric hindrance, it is very difficult to fully convert the secondary hydroxyl groups to other functional groups such as acrylates, epoxies, and vinyl ethers, especially in the presence of primary hydroxyl groups. Incomplete conversion of hydroxyl groups makes it less suitable for applications requiring low moisture uptake and low optical absorption in the 1300-1600 nm wavelength regions.
Therefore there is a need for a fluorinated alcohol having at least 3 primary alcohol groups per molecule. Such alcohol is suitable to being converted to crosslinkers containing at least 3 functional groups selected from the group consisting of acrylate, epoxy and vinyl ether. The crosslinkers may be used in fluorinated optical coating and waveguide compositions.
SUMMARY OF THE INVENTION
A fluorinated multifunctional alcohol having at least 3 primary hydroxyl groups is synthesized. The alcohol is subsequently converted to multifunctional crosslinkers such as acrylates, epoxies and vinyl ethers.
One object of this invention is to provide a new fluorinated multifunctional alcohol having at least three primary hydroxyl groups.
It is another object of the invention to provide a multifunctional alcohol that is a suitable precursor to fluorinated multifunctional acrylates, epoxies, and vinyl ethers.
Another object of the invention is to provide a new fluorinated multifunctional acrylate synthesized from the fluorinated multifunctional alcohol of the present invention.
It is still another object of the invention to provide a coating composition comprising the multifunctional acrylate of the present invention.
Still another object of this invention is to provide a method for producing an optical coating comprising (I) forming a coating composition comprising at least one acrylate and at least one free radical initiator; (II) coating the composition into a film on a substrate having a substantially uniform thickness; and (III) curing the coating composition by exposure to an actinic radiation or heat, depending on the type of the initiator.
Yet still another object of this invention is to provide a waveguide device formed by patterning the coating composition of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The fluorinated multifunctional alcohol of the present invention has at least three primary hydroxyl groups. Its structure can be described using the following formula:
R
F
&Parenopenst;CH
2
OH)
n
0
wherein R
F
is a fluorinated mono- or multi-valent radical such as aromatic and aliphatic esters, ethers, amides, urethanes, and mixtures thereof, and no is an integer of at least 3. Preferably the fluorine content in R
F
is at least 20% by weight to allow for sufficient solubility of the crosslinker in a fluorinated coating composition.
In a preferred embodiment the fluorinated multifunctional alcohol of the present invention has the following formula:
(HOH
2
C&Parenclosest;
n
1
R
1
-Rf-R
2
&Parenopenst;CH
2
OH)
n
1
wherein Rf is a monomeric or polymeric perfluorinated alkylene, oxyalkylene, arylene, oxyarylene, and mixtures thereof; R
1
and R
2
are monomeric or polymeric multi-valent radicals such as aromatic and aliphatic esters, ethers, amides, urethanes, and mixtures thereof; and n
1
is an integer of at least 2, preferably from 2 to 4. Typically Rf has a molecular weight of at least 25% of the molecular weight of the alcohol to allow for sufficient solubility of the crosslinker in a fluorinated coating composition and to reduce optical absorption in the wavelength region of 1300-1600 nm.
In one preferred embodiment the fluorinated multifunctional primary alcohol, A, is synthesized from a fluorinated diol, B, and a carboxylic compound, C, containing one hydroxy-reacting group and at least two primary alcohol groups. B and C react to form an ester.
wherein Rf is a monomeric or polymeric perfluorinated alkylene, oxyalkylene, arylene, oxyarylene, and mixtures thereof; R
3
and R
4
are monomeric or polymeric divalent moieties such as alkylene, oxyalkylene, alkylene sulfide, arylene, oxyarylene, arylene sulfide, siloxane, and mixtures thereof; X stands for a hydroxyl, halide or alkoxy group, R
5
is an aliphatic or aromatic moiety and n
1
ranges from 2 to 4. In the above scheme R
1
and R
2
in A represent the following ester groups formed, respectively:
To avoid polymerization during the reaction it is preferred that the hydroxyl groups in C be protected before the reaction and then de-protected after the reaction.
Examples of suitable fluorinated diols, B, include, but are not limited to, 1H,1H,9H, 9H-perfluoro-1,9-nonanediol, 1H,2H,3H,3H-perfluorononane-1,2-diol, 1H,1H,10H,10H-perfluoro-1,10-decanediol, 1H,1H,12H,12H-perfluoro-1,12-dodecanediol, 1H,1H,16H,16H-perfluoro-1,16-hexadecanediol, 1H 1H,8H,8H-perfluorotetraethyleneglycol, fluoro-poly(alkylene) diol, ethoxylated fluoropoly(alkylene) diols, fluoropoly(oxyalkylene) diols having the following structures:
HOCH
2
O(CF
2
O)
m
CH
2
OH
HOCH
2
CF
2
O(CF
2
CF
2
O)
n
CF
2
CH
2
OH
HOCH
2
CF
2
CF
2
O(CF
2
CF
2
CF
2
O)
n
CF
2
CF
2
CH
2
OH
HOCH
2
CF
2
CF
2
CF
2
O(CF
2
CF
2
CF
2
CF
2
O)
n
CF
2
CF
2
CF
2
CH
2
OH
HOCH
2
CF
2
O(CF
2
CF
2
O)
n
(CF
2
O)
m
CH
2
OH
HOCH
2
CF
2
O(CF
2
CF
2
O)
m
(CF
2
CF
2
CF
2
CF
2
O)
n
(CF
2
CF
2
O)
m
CF
2
CH
2
OH
and
HOCH
2
CF
2
O(CF
2
CF
2
O)
m
(CF
2
CF
2
CF
2
O)
n
CF
2
CF
2
O(CF
2
CF
2
CF
2
O)
n
(CF
2
CF
2
O)
m
CF
2
CH
2
OH
wherein m and n are independent integers, perfluoropolyether diols and ethoxylated perfluoropolyether diols such as Fluorolink D, D10, E and E10 commnercially available

Affiliated with

Also associated with

Rating

Fluorinated crosslinker and composition does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Fluorinated crosslinker and composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fluorinated crosslinker and composition will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3284100