Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Compositions to be polymerized by wave energy wherein said...
Reexamination Certificate
2000-07-20
2003-03-04
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Compositions to be polymerized by wave energy wherein said...
C522S090000, C522S097000, C522S182000, C522S120000, C522S121000, C522S028000, C522S173000, C522S174000, C428S378000, C428S380000, C428S388000, C428S426000, C428S441000
Reexamination Certificate
active
06528553
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a curable composition having high speed curing and capable of producing cured products by polymerization without impairing mechanical properties. In particular, the curable composition of the present invention is a liquid curable composition that can be formulated for use in a wide variety of applications including, for example, coatings and/or binders. In particular, these curable compositions offer relatively fast cure speeds that offer advantages in many application such as in the production of fiber optics wherein production speeds make it desirable to utilize primary coatings, secondary coatings (including, for example transparent and/or colored secondary coatings), inks, matrix materials and/or bundling materials that can be cured rapidly.
BACKGROUND OF THE INVENTION
In the production of optical fibers, a resin coating is applied immediately after spinning molten glass fibers for protection and reinforcement. A known structure of the resin coating has been a double-layered coating structure consisting of a primary coating layer of a flexible resin which is coated on the surface of optical fibers and a secondary coating layer of a rigid resin which is provided over the primary coating layer. A so-called optical fiber ribbon has been known in the art in the application of optical fibers provided with such a resin coating. The optical fiber ribbon is made from several optical fibers, e.g., four or eight optical fibers, arranged on a plane and secured with a binder to produce a ribbon structure having a rectangular cross section. A resin composition for forming the primary coating layer is called a soft coating, a resin composition for forming the secondary coating layer is called a hard coating, and a material for binding several optical fibers to produce the optical fiber ribbon structure is called a ribbon matrix material. Often, the fibers for identification purposes will be further coated with an ink, which is a curable resin comprising a colorant (such as a pigment and/or a dye), or the secondary coating may be a colored secondary coating (i.e, comprise a colorant). In addition, a material for the further binding of several optical fiber ribbons to produce multi-core optical fiber ribbons is called a bundling material.
Characteristics required for curable resins used as coating materials for optical fibers include: being a liquid at room temperature and having a sufficiently low viscosity for excellent coating; exhibiting superior storage stability and no compositional distribution as a liquid; providing good productivity owing to a high cure speed; having sufficient strength and superior flexibility after curing; exhibiting very little physical change during wide range temperature changes, in particular primary coatings should have very low Tg; having superior heat resistance and superior resistance to hydrolysis; showing superior long term reliability due to little physical change over time; showing superior resistance to chemicals such as acids and alkalis; absorbing only a small amount of moisture and water; exhibiting superior light resistance; exhibiting high oil resistance; producing little hydrogen gas which adversely affects optical fibers; and the like.
In the production of optical fibers and optical fiber assemblies, one of the limitations on how fast the production line can be operated is the cure speed of the coatings and/or binder. Accordingly, it is desirable to develop coatings and/or binders with faster cure speed.
The resin composition for coating optical fibers must remain a liquid during production of the coating, and after being stored for a long period of time. If the resin composition solidifies entirely or partially during storage by (e.g.) flocculation or crystallization, the composition must be heated to avoid any problems in the coating process of the optical fibers, thereby impairing handling of the resin composition.
An object of the present invention is to provide a liquid curable resin composition which exhibits a faster cure speed and better aging characteristics, for example, lower yellowing of the cured composition. A further object of the present invention is to provide coatings having a low Tg (glass transition-temperature).
SUMMARY OF THE INVENTION
The present invention provides a curable composition, comprising: a (meth)acrylate urethane compound derived from a polypropylene glycol or a copolymer comprising propyleneoxide and ethyleneoxide (herein after also just named polypropyleneglycol) having a molecular weight between 1,000 and 13,000 and an amount of unsaturation less than 0.01 meq/g, and/or mixtures of (meth)acrylate urethane compounds derived from such a polypropylene glycol and other polyols. The liquid curable resin composition of the present invention has improved liquid stability, and improved cure speed; the cured products have superior mechanical characteristics. The liquid curable resin composition can be used as a coating material for optical fibers, adhesives, and the like. The composition is particularly suitable as a coating material for optical fibers for which long-term stability is required. Also, the composition can be formulated to achieve low Tg, e.g. between −70° C. and −30° C.
In particular, the compositions of the present invention offer relatively fast cure speeds which offer advantages in many applications, including the production of fiber optics wherein production speeds make it desirable to utilize primary coatings, secondary coatings (including, for example transparent and/or colored secondary coatings), inks, matrix materials and/or bundling materials that can be cured rapidly.
Furthermore, the present invention provides a method for forming the curable composition of the present invention comprising a process for forming the urethane compound by reacting
(a.1) a polypropylene glycol or a polypropylene/ethylene glycol copolymer having a molecular weight between 1,000 and 13,000 and an amount of unsaturation less than 0.01 meq/g, and
(a.2) optionally, a further polyol or mixture of polyols;
(b) a polyisocyanate, and
(c) a (meth)acrylate containing a hydroxyl group, wherein the process includes (i) reacting said glycol (a.1 and if applicable a.2), the polyisocyanate, and the hydroxyl group-containing (meth)acrylate altogether; (ii) reacting said glycol and the polyisocyanate, and reacting the resulting product with the hydroxyl group-containing (meth)acrylate; (iii) reacting the polyisocyanate and the hydroxyl group-containing (meth)acrylate, and reacting the resulting product with said glycol; or (iv) reacting the polyisocyanate and the hydroxyl group-containing (meth)acrylate, reacting the resulting product with said glycol, and reacting the hydroxyl group-containing (meth)acrylate once more.
In a further aspect of the invention, a radiation curable resin is provided, for a primary coating of an optical fiber comprising (a) 40-95 wt % of polyurethane having a polyoxyalkylene structure, in which the weight ratio of propylene oxide and ethylene oxide is 100:0 to 80:20, and an ethylenically unsaturated group, (b) 3-50 wt % of mono-functional (meth)acrylate of which the homopolymer has a glass transition temperature of 20° C. or less, and (c) 0.01-5 wt % of primary or secondary amine compound, wherein wt % is based on the total amount of the components (a), (b), and (c).
A DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
(Meth)acrylic—as used herein is understood to represent separately and collectively acrylic, methacrylic and mixtures thereof. Similarly, (meth)acrylate as used herein is understood to represent separately and collectively acrylate, (meth)acrylate, and mixtures thereof.
Polypropylene glycol or polypropylene/ethylene copolymer glycol (having a specified molecular weight and a specified amount of unsaturation)—as used herein is understood to refer to a polypropylene glycol comprising composition having a plurality of polypropylene glycol moieties and optionally ethylene glycol moieties that on average hav
Abel Adrianus G. M.
Alkema Duurt P. W.
Komiya Zen
Mase Masahito
Ukachi Takashi
DSM N.V.
McClendon Sanza L.
Pillsbury & Winthrop LLP
Seidleck James J.
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