WO2010008174A2 - Photocurable coating composition which provides a coating layer having improved hot water resistance - Google Patents
Photocurable coating composition which provides a coating layer having improved hot water resistance Download PDFInfo
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- WO2010008174A2 WO2010008174A2 PCT/KR2009/003853 KR2009003853W WO2010008174A2 WO 2010008174 A2 WO2010008174 A2 WO 2010008174A2 KR 2009003853 W KR2009003853 W KR 2009003853W WO 2010008174 A2 WO2010008174 A2 WO 2010008174A2
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- diacrylate
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
- C09D175/04—Polyurethanes
- C09D175/06—Polyurethanes from polyesters
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
- C09D175/04—Polyurethanes
- C09D175/14—Polyurethanes having carbon-to-carbon unsaturated bonds
- C09D175/16—Polyurethanes having carbon-to-carbon unsaturated bonds having terminal carbon-to-carbon unsaturated bonds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/48—Polyethers
- C08G18/4854—Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/67—Unsaturated compounds having active hydrogen
- C08G18/671—Unsaturated compounds having only one group containing active hydrogen
- C08G18/672—Esters of acrylic or alkyl acrylic acid having only one group containing active hydrogen
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/75—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic
- C08G18/751—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring
- C08G18/752—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group
- C08G18/753—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group containing one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group having a primary carbon atom next to the isocyanate or isothiocyanate group
- C08G18/755—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group containing one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group having a primary carbon atom next to the isocyanate or isothiocyanate group and at least one isocyanate or isothiocyanate group linked to a secondary carbon atom of the cycloaliphatic ring, e.g. isophorone diisocyanate
Definitions
- the present invention relates to a photocurable coating composition which provides upon curing a coating layer having improved hot water resistance, and to an optical fiber comprising the coating layer.
- a coating layer which is formed on a glass fiber core on the preparation of optical fibers is required to have high adhesion strength thereto even after being dipped in hot water.
- U.S. Patent No. 6,599,956 discloses a photocurable coating composition comprising oligomers synthesized from specific amounts of crystalline polyols and non-crystalline polyols.
- EP Patent No. 1362016 discloses a photocurable coating composition comprising photocurable urethane oligomers made of polyester polyols in an amount of 50 to 70% by weight, which provides upon curing a coating layer with good water resistance when dipped in 60 ° C water.
- coating layers formed from these compositions show some improvements in terms of adhesion strength to a glass fiber core or hot water resistance, they need a prolonged curing time and still undergo gradual deterioration of hot water resistance during a long-term dipping, thereby being easily separated from the glass fiber.
- a photocurable coating composition comprising: (A) 30 to 90 % by weight of a photopolymerizable urethane acrylate oligomer which is synthesized using a polyol copolymer, a polyisocyanate, an acrylate alcohol, a urethane reaction catalyst, and a polymerization inhibitor; (B) 5 to 60 % by weight of a reactive monomer containing at least one acrylate, methacrylate, or vinyl group; and (C) 1 to 15 % by weight of a photoinitiator.
- Fig. 1 shows a schematic illustration of the curing process of a coating composition coated onto a glass fiber core of an optical fiber by UV irradiation.
- a photocurable coating composition of the present invention is characterized in comprising a urethane acrylate oligomer composed of copolymerized polyester polyol and polyether polyol, which is synthesized using a polyol copolymer, a polyisocyanate, an acrylate alcohol, a urethane reaction catalyst, and a polymerization inhibitor.
- a photocurable coating composition of the present invention is essentially composed of (A) 30 to 90 % by weight of a photopolymerizable urethane acrylate oligomer; (B) 5 to 60 % by weight of a reactive monomer containing at least one acrylate, methacrylate, or vinyl group; and (C) 1 to
- a photoinitiator 15 % by weight of a photoinitiator, but may further comprise (D) 0.01 to 0.5 % by weight of an amine-additive, and (E) 1 to 5 % by weight of a silane-based monomer, a stabilizer, or a mixture thereof.
- Photopolymerizable urethane acrylate oligomer (A) Photopolymerizable urethane acrylate oligomer
- the photopolymerizable urethane acrylate oligomer used in the present invention is synthesized using (i) a polyol copolymer, (ii) a polyisocyanate, (iii) an acrylate alcohol, (iv) a urethane reaction catalyst, and (v) a polymerization inhibitor.
- the photopolymerizable urethane acrylate oligomer may be composed of 10:90 to 30:70 weight ratio of polyether polyol and polyester polyol, and have a number average molecular weight of 5,000 to 50,000 (determined by gel permeation chromatography (GPC)) and a viscosity of 10,000 to 30,000 cps (determined by Brookfield viscometer HB type, spindle #51, at 40°C).
- GPC gel permeation chromatography
- the photopolymerizable urethane acrylate oligomer is used in an amount ranging from 30 to 90 % by weight based on the total weight of the coating composition.
- amount is less than 30 % by weight, there might occur a loss during microbending, and when more than 90 % by weight, the workability becomes poor as the result of high viscosity.
- the polyol copolymer (i) has a number average molecular weight of 100 to 10,000, and preferably comprises a repeating unit of -CH 2 CH 2 O- or - CH 2 CH(CH 2 CH 3 )O-.
- polyol copolymer examples include polyester polyol, polyether polyol, polycarbonate polyol, polycarprolactone polyol, a tetrahydrofuran propylene oxide ring opening copolymer, ethylene glycol, propylene glycol, 1 ,4-butanediol, 1 ,5-pentanediol, 1 ,6-hexandiol, neopentyl glycol, 1 ,4-cyclohexane dimethanol, bisphenol-A type of diols, and a mixture thereof.
- polyether polyol and a mixture of 10 to 30 % by weight of a tetrahydrofuran propylene oxide ring opening copolymer and 70 to 90 % by weight of polyester polyol.
- the polyol copolymer is preferably used in an amount ranging from 30 to 75 % by weight based on the total weight of the photopolymerizable urethane acrylate oligomer.
- polyisocyanate (ii) used in the present invention include 2,4-tolyenediisocyanate, 2,6-tolyenediisocyanate, 1,3- xylenediisocyanate, 1,4-xylenediisocyanate, 1 ,5-naphthalenediisocyanate, 1,6- hexanediisocyanate, isophoronediisocyanate (IPDI), and a mixture thereof.
- the polyisocyanate is preferably used in an amount ranging from 10 to 40 % by weight based on the total weight of the photopolymerizable urethane acrylate oligomer.
- Preferred examples of the acrylate alcohol (iii), which comprises at least one (meth)acrylate and hydroxy group include 2- hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2- hydroxybutyl(meth)acrylate, 2-hydroxyethylacrylate, 2-hydroxypropylacrylate, 2-hydroxy-3-phenyloxypropyl(meth)acrylate, 4-hydroxybutylacrylate, neopentylglycolmono(meth)acrylate, 4-hydroxycyclohexyl(meth)acrylate, 1 ,6- hexanediolmono(meth)acrylate, pentaerythritolpenta(meth)acrylate, dipentaerythritolpenta(meth)acrylate, and a mixture thereof.
- the acrylate alcohol is preferably used in an amount ranging from 10 to 35 % by weight based on the total weight of the photopolymerizable urethan
- Preferred examples of the urethane reaction catalyst (iv), which is used in the urethane reaction include copper naphthenate, cobalt naphthenate, zinc naphthenate, n-butyltinlaurate, dibutyltindilaurate, tristhylamine, 2- methyltriethylenediamide, and a mixture thereof.
- the urethane reaction catalyst is preferably used in an amount ranging from 0.01 to 1 % by weight based on the total weight of the photopolymerizable urethane acrylate oligomer.
- Preferred examples of the polymerization inhibitor (v) include hydroquinone, hydroquinone monomethylether, para-benzoquinone, phenothiazine, and a mixture thereof.
- the polymerization inhibitor is preferably used in an amount ranging from 0.01 to 1 % by weight based on the total weight of the photopolymerizable urethane acrylate oligomer.
- Said photopolymerizable urethane acrylate oligomer (A) may be synthesized using above components as follows: A polyisocyanate (ii) is added in a round-bottom flask equipped with a stirrer. While stirring, a part or all of a urethane reaction catalyst (iv) is added and a polyol copolymer (i) is slowly added thereto. The mixture is allowed to react at about 70 to 80°C until the NCO concentration of the resulting product reaches a predetermined level, to obtain a urethane prepolymer.
- a polymerization inhibitor (v), an acrylate alcohol (iii) and, if necessary, the remaining amount of the urethane reaction catalyst (iv) are slowly added to the flask containing the urethane prepolymer, and the mixture is allowed to react at 80 0 C.
- the reaction is allowed to terminate after disappearance of an NCO peak at about 2270cm "1 is confirmed by an infrared spectrometer, to obtain a photopolymerizable urethane acrylate oligomer.
- the reactive monomer (B) used in the present invention which has at least one acrylate group, methacrylate group or vinyl group serves as a diluent to adjust a viscosity of the oligomer component to an appropriate level for working, and thus preferably has a low number average molecular weight of 100 to 300.
- the reactive monomer may contain one or more and various functional groups, preferably 1 to 8 propylene oxide groups (-OC 3 H 6 -).
- a reactive monomer which can provide a film having a high tensile strength and low curing shrinkage is preferred.
- Preferred examples thereof include phenoxyethylacrylate, phenoxyethyleneglycolacrylate, phenoxytetraethyleneglycolacrylate, phenoxyhexaethyleneglycolacrylate, isobonylacrylate (IBOA), isobonylmethacrylate, N-vinylpyrrolidone (N-VP), N-vinylcaprolactam (N-VC), acryloyl morpholine (ACMO), bisphenol ethoxylate diacrylate, ethoxylate phenol monoacrylate, polyethyleneglycol 400 diacrylate, tripropyleneglycol diacrylate, trimethyl propane triacrylate (TMPTA), polyethyleneglycol diacrylate, ethyleneoxide-addition triethylpropantriacrylate, pentaerythritol tetraacrylate (PETA), 1 ,4-butanediol diacrylate, 1,6-hexanediol diacrylate, ethoxylated pen
- a monomer which enhances adhesion strength to a substrate may further used.
- the reactive monomer is used in an amount ranging from 5 to 60 % by weight based on the total weight of the coating composition.
- amount is less than 5 % by weight, it may be difficult to lower a viscosity of the oligomer component to a level suitable for working, i.e., a range of 3,000 to 10,000 cps (25 "C), and when more than 60 % by weight, poor properties such as high viscosity, enlargement of particles, unbalanced surface upon curing, and optical losses occur, due to decreases of the curing shrinkage and thermal stability at high temperature.
- the photoinitiator (C) is used to help a fast curing speed of a resin itself, in order to keep a pace with optical fiber coating speed of l,500m/min or higher.
- the photoinitiator forms free radicals by UV energy and attacks double bonds in resins to induce polymerization.
- Preferred examples thereof include Irgacure #184
- the photoinitiator is used in an amount ranging from 1 to 15 % by weight based on the total weight of the coating composition.
- the amine additive is used to prevent a coating composition from polymerization caused by a high temperature or a light before cured, from a hydrogen gas release after cured, and from transmission losses, as well as to provide a fast curing speed.
- Preferred examples thereof include diallylamine, diisopropylamine, diethylamine, diethylhexylamine, triethylamine, N-methyldiethanolamine, ethanolamine, diethanolamine, and a mixture thereof.
- the amine additives are preferably used in an amount ranging from 0.01 to 0.5 % by weight based on the total weight of the coating composition.
- the photocurable coating composition of the present invention may comprise a silane-based monomer, a stabilizer or a mixture thereof to inhibit decrease of adhesion strength between the coating layer and glass fiber substrate.
- the silane-based monomer, the stabilizer or the mixture thereof may be used in an amount ranging from 1 to 5 % by weight based on the total weight of the coating composition. When the amount is out of the above scope, lowering of a curing speed may occur.
- the silane-based monomer functions to enhance adhesion strength between the coating layer and glass fiber substrate as well as to lower a water absorption ratio of a resin composition.
- Representative examples of the silane-based monomer include vinyl trimethoxy silane commercially available from Chisso Co. (Japan), vinyl trimethoxy silane from others, vinyl tri(methoxyethoxy)silane, gamma-methacryl oxypropyltrimethoxy silane, gamma-glycid oxypropylmethoxy silane, gamma-aminopropyltriethoxy silane, gamma-mercaptopropyltrimethoxy silane, and a mixture thereof.
- stabilizer which acts to improve thermal, oxidative and storage stabilities of a coating composition
- Irganox 1010, Irganox 1035, and Irganox 1076 which are commercially available from Ciba Geigy Co, and a mixture thereof.
- a method for preparing the inventive photocurable coating composition is as follows:
- a photopolymerizable urethane acrylate oligomer (A), a reactive monomer (B), a photoinitiator (C), optionally an amine-additive (D) and other additives (E) are added to a reactor.
- the mixture is stirred under a temperature of 15 to 50 0 C, a humidity of 60% or less and a homogeneous speed of l,000rpm or higher, by using a dispersion impeller.
- the viscosity of the photopolymerizable urethane acrylate oligomer (A) increases, resulting in unsmooth processing, and when the reaction is carried out at a temperature higher than 50°C, the photoinitiator (C) may cause undesirable curing due to the formation of radicals.
- the reaction is carried out at a humidity higher than 60%, bubbles may be generated from a resin composition during a subsequent coating process and a side-reaction that non-reactants react with moistures in air may occur. Further, when the mixture is stirred at a speed lower than l,000rpm, unsatisfactory mixing may be achieved.
- the inventive coating composition is used to prepare a coating layer or film, and the coating layer or film has the following characteristics:
- the film remains tightly adhered on the glass even after being dipped in 45 to 85°C water for a prolonged time (e.g., at least 60 days). If the composition is used to prepare a lOO ⁇ m-thick film coated on a glass fiber substrate by curing, the film has a 2.5% secant modulus of 0.1 to 0.3 kgf/mm 2 and an adhesion strength to the glass fiber substrate of 1 to 3 N (Newton).
- An optical fiber having a 10 to 30 ⁇ m-thick coating layer can be prepared by coating the inventive coating composition on a glass fiber and curing the coating by light irradiation (exposure to a UV lamp) ⁇ see Fig. 1). On curing with a UV-lamp, a D-bulb having a light intensity of 0.5 ⁇ 3 J/cm 2 and a speed of 30 ⁇ 150fpm may be used.
- the optical fiber prepared by above method has improved hot water resistance, without causing the photosignal loss or reduction of adhesion strength even when dipped in hot water for a prolonged time. Accordingly, the inventive optical fiber shows improved thermal, mechanical, and chemical stabilities, in particular, no delamination when dipped in 45 ⁇ 85°C water for a prolonged time (e.g., at least 60 days).
- Preparation Example 1 Preparation of a photopolymerizable urethane acrylate oligomer (A) 138.32g (0.62 mole) of isophoronediisocyanate (IPDI; Lyondell chemical Co.) and 0.17g of dibutyltindilaurate (Songwon industrial Co.) were added to a 2L round-bottom flask equipped with a stirrer. The mixture was heated to 80 0 C, and 109.03g (0.11 mole) of polytetramethyleneglycol polyol (PTMG; BASF Co.) with a number average molecular weight of 1000 was added thereto.
- IPDI isophoronediisocyanate
- PTMG polytetramethyleneglycol polyol
- the NCO concentration (theoretically 8.67%) of the resulting product was adjusted to 7.5 to 8.5%.
- 716.5Og (0.36 mole) of polypropyleneglycol polyol (PPG; Korea Polyol Co.) with a number average molecular weight of 2000 was added thereto.
- the NCO concentration (theoretically 1.07%) of the resulting product was adjusted to 0.7 to 1.0% to obtain a urethane prepolymer.
- the oligomer obtained above has a number average molecular weight of 23,000g/mol (determined by gel permeation chromatography (GPC)), a viscosity of 14,000cps at 25 °C, and an average urethane bonding number of 4.
- the NCO concentration (theoretically 1.08%) of the resulting product was adjusted to 0.7 to 1.0% to obtain a urethane prepolymer.
- 2.15g of hydroquinonemonomethylether (HQMME; Eastman Co.), 38.5 Ig of 2- hydroxyethylacrylate (2-HEA; Nippon shokubai Co.) and O. lg of dibutyltindilaurate were slowly added thereto.
- the mixture was allowed to react at 80 0 C for 1 hour.
- the reaction was allowed to terminate after disappearance of an NCO peak at 2270cm '1 is confirmed by an infrared spectrometer, to obtain a photopolymerizable urethane acrylate oligomer.
- the oligomer obtained above has a number average molecular weight of 21,000g/mol (determined by gel permeation chromatography (GPC)), a viscosity of 12,100cps at 25°C, and an average urethane bonding number of 4.
- the reaction was allowed to terminate after disappearance of an NCO peak at 2270cm "1 is confirmed by an infrared spectrometer, to obtain a photopolymerizable urethane acrylate oligomer.
- the oligomer obtained above has a number average molecular weight of 21,000g/mol (determined by gel permeation chromatography (GPC)), a viscosity of 12,000cps at 25°C, and an average urethane bonding number of 4.
- the mixture was allowed to react at 80°C for 3 hour.
- the reaction was allowed to terminate after disappearance of an NCO peak at 2270cm "1 is confirmed by an infrared spectrometer, to obtain a photopolymerizable urethane acrylate oligomer.
- the oligomer obtained above has a number average molecular weight of 22,000g/mol (determined by gel permeation chromatography (GPC)), a viscosity of 15,200cps at 25 °C, and an average urethane bonding number of 4.
- the mixture was allowed to react at 80°C for 3 hour.
- the reaction was allowed to terminate after disappearance of an NCO peak at 2270cm '1 is confirmed by an infrared spectrometer, to obtain a photopolymerizable urethane acrylate oligomer.
- the oligomer obtained above has a number average molecular weight of 24,000g/mol (determined by gel permeation chromatography (GPC)), a viscosity of 18,200cps at 25 "C, and an average urethane bonding number of 4.
- a viscosity of a composition sample was measured in a torque ranging from 50 to 90% by using a Brookfield DV III+ viscometer, #31 spindle, according to ASTM D-2196.
- a composition sample was coated on a 20x20 cm glass plate by using a bar coater having a fixed thickness of 7 to 1 Omil. After being placed into a fixing frame, the coated film was cured under a nitrogen gas (401pm) by using a 600W and 9mm D-bulb (model DRSl 0/12-QN; Fusion Co.) with a light intensity of 2.5 J/cm 2 and a speed of 30fpm to obtain a cured lOO ⁇ m-thick film. The cured film was separated from the glass plate and cut into a 13mm- width film by using a JDC cutter. The cut film was equilibrated in a desiccator of 23 0 C and RH 50% for one day. Then, 2.5% secant modulus was measured by pulling the film at a speed of 25mm/min by using 4443 UTM (Instron Co.).
- a composition sample was coated on a 20x20 cm glass plate by using a bar coater having a fixed thickness of 5mil. Then, a secondary coating was coated in a thickness of lOmil thereon. After being placed into a fixing frame, the coated film was cured under a nitrogen gas (401pm) by using a 600W and 9mm D-bulb (model DRS10/12-QN; Fusion Co.) with a light intensity of 2.5 J/cm 2 and a speed of 30fpm to obtain a cured lOO ⁇ m-thick film. The cured film was separated from the glass plate and cut into a 20mm-width film by using a JDC cutter.
- the cut film was equilibrated in a desiccator of 23°C and RH 50% for one day. Then, a degree of adhesion strength to a glass fiber substrate was measured by pulling the film at an angle of 90° and a speed of 25mm/min by using 4443 UTM (Instron Co.).
- Tg Glass transition temperature
- a composition sample was coated on a 20x20 cm glass plate by using a bar coater. After being placed into a fixing frame, the coated film was cured under a nitrogen gas (401pm) by using a 600W and 9mm D-bulb (model DRS10/12-QN; Fusion Co.) with a light intensity of 2.5 J/cm 2 and a speed of 30fpm to obtain a cured 600 ⁇ m-thick film. The cured film was cut into a 15mm-length and 10mm- width film. The cut film was placed in DMTA IV (Dynamic mechanical temperature analysis; Rheometry) and geometrical values for the film were input thereto. The measurement was carried out by cooling the film to about -100°C and warming it to about 60°C by 2°C/min. The test frequency was 1.0 radian/sec. A glass transition temperature was calculated from a tan delta peak in the graph obtained.
- a glass fiber having a diameter of 125 ⁇ m was passed through a syringe (2 mL) containing a coating composition and the coated glass fiber was UV- cured, as shown in Fig. 1.
- the UV-curing was carried out under a light intensity of 1.0 J/cm 2 (UVA region) and a speed of 150fpm using a D-bulb of a Fusion UV apparatus.
- the thickness of the coating layer was in the range of 10 to 30 ⁇ m.
- the coated and cured fiber was dipped in each of 45, 65 and 85°C water. After 10, 30 and 60 days from the dipping, the fiber was pulled out from water, dried at room temperature for 10 minutes and cut into lOcm-long fragments. Then, for ten fiber fragments, an interface between the glass fiber and the coating layer was observed by an optical microscope (200-fold magnification), to count the number of droplet penetrated at the interface.
- the coating layers obtained from the compositions of Examples 1 to 9 exhibited high hot water resistance and adhesion strength to the glass fiber substrate even after being dipped in hot water for a prolonged time, while those obtained from the compositions of Comparative Examples 1 to 6, a phenomenon (delamination) separated from the glass fiber substrate with the dipping time.
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Abstract
The present invention provides a photocurable coating composition comprising a urethane acrylate oligomer which is synthesized using a polyol copolymer, a polyisocyanate, an acrylate alcohol, a urethane reaction catalyst, and a polymerization inhibitor, and an optical fiber using the same, the optical fiber showing improved water resistance and excellent thermal, mechanical and chemical stabilities.
Description
PHOTOCURABLE COATING COMPOSITION
WHICH PROVIDES A COATING LAYER HAVING IMPROVED HOT WATER RESISTANCE
FIELD OF THE INVENTION
The present invention relates to a photocurable coating composition which provides upon curing a coating layer having improved hot water resistance, and to an optical fiber comprising the coating layer.
BACKGROUND OF THE INVENTION
A coating layer which is formed on a glass fiber core on the preparation of optical fibers is required to have high adhesion strength thereto even after being dipped in hot water.
Hitherto, various photocurable coating compositions for forming such a coating layer have been reported. Among them, however, a coating layer prepared from a UV-curable coating composition comprising oligomers synthesized from crystalline polyols undergoes undesired crystallization at a low temperature, which causes significant loss in optical efficiency of the resulting optical fiber.
In order to lower the freezing point of a coating layer for an optical fiber and enhance low temperature stability thereof, U.S. Patent No. 6,599,956 discloses a photocurable coating composition comprising oligomers synthesized from specific amounts of crystalline polyols and non-crystalline polyols. In addition, EP Patent No. 1362016 discloses a photocurable coating composition comprising photocurable urethane oligomers made of polyester polyols in an amount of 50 to 70% by weight, which provides upon curing a coating layer with good water resistance when dipped in 60 °C water. Although coating layers formed from these compositions show some improvements in terms of adhesion strength to a glass fiber core or hot water resistance, they need a prolonged curing time and still undergo gradual
deterioration of hot water resistance during a long-term dipping, thereby being easily separated from the glass fiber.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a photocurable coating composition which, upon curing, provides a coating layer having improved physical properties in terms of hot water resistance and adhesion strength to the glass fiber substrate, even after being dipped in hot water during a prolonged period.
It is another object of the present invention to provide an optical fiber comprising the coating layer.
In accordance with one aspect of the present invention, there is provided a photocurable coating composition comprising: (A) 30 to 90 % by weight of a photopolymerizable urethane acrylate oligomer which is synthesized using a polyol copolymer, a polyisocyanate, an acrylate alcohol, a urethane reaction catalyst, and a polymerization inhibitor; (B) 5 to 60 % by weight of a reactive monomer containing at least one acrylate, methacrylate, or vinyl group; and (C) 1 to 15 % by weight of a photoinitiator.
BRIEF DESCRIPTION OF DRAWINGS
The above and other objects and features of the present invention will become apparent from the following description of the invention, when taken in conjunction with the accompanying Fig. 1, which shows a schematic illustration of the curing process of a coating composition coated onto a glass fiber core of an optical fiber by UV irradiation.
DETAILED DESCRIPTION OF THE INVENTION
A photocurable coating composition of the present invention is characterized in comprising a urethane acrylate oligomer composed of
copolymerized polyester polyol and polyether polyol, which is synthesized using a polyol copolymer, a polyisocyanate, an acrylate alcohol, a urethane reaction catalyst, and a polymerization inhibitor.
A photocurable coating composition of the present invention is essentially composed of (A) 30 to 90 % by weight of a photopolymerizable urethane acrylate oligomer; (B) 5 to 60 % by weight of a reactive monomer containing at least one acrylate, methacrylate, or vinyl group; and (C) 1 to
15 % by weight of a photoinitiator, but may further comprise (D) 0.01 to 0.5 % by weight of an amine-additive, and (E) 1 to 5 % by weight of a silane-based monomer, a stabilizer, or a mixture thereof.
Hereinafter, each component is described in detail.
(A) Photopolymerizable urethane acrylate oligomer The photopolymerizable urethane acrylate oligomer used in the present invention is synthesized using (i) a polyol copolymer, (ii) a polyisocyanate, (iii) an acrylate alcohol, (iv) a urethane reaction catalyst, and (v) a polymerization inhibitor. Preferably, the photopolymerizable urethane acrylate oligomer may be composed of 10:90 to 30:70 weight ratio of polyether polyol and polyester polyol, and have a number average molecular weight of 5,000 to 50,000 (determined by gel permeation chromatography (GPC)) and a viscosity of 10,000 to 30,000 cps (determined by Brookfield viscometer HB type, spindle #51, at 40°C).
The photopolymerizable urethane acrylate oligomer is used in an amount ranging from 30 to 90 % by weight based on the total weight of the coating composition. When the amount is less than 30 % by weight, there might occur a loss during microbending, and when more than 90 % by weight, the workability becomes poor as the result of high viscosity.
(i) Polyol copolymer
The polyol copolymer (i) has a number average molecular weight of 100 to 10,000, and preferably comprises a repeating unit of -CH2CH2O- or -
CH2CH(CH2CH3)O-.
Preferred examples of the polyol copolymer include polyester polyol, polyether polyol, polycarbonate polyol, polycarprolactone polyol, a tetrahydrofuran propylene oxide ring opening copolymer, ethylene glycol, propylene glycol, 1 ,4-butanediol, 1 ,5-pentanediol, 1 ,6-hexandiol, neopentyl glycol, 1 ,4-cyclohexane dimethanol, bisphenol-A type of diols, and a mixture thereof. Among them, more preferred are polyether polyol, and a mixture of 10 to 30 % by weight of a tetrahydrofuran propylene oxide ring opening copolymer and 70 to 90 % by weight of polyester polyol. The polyol copolymer is preferably used in an amount ranging from 30 to 75 % by weight based on the total weight of the photopolymerizable urethane acrylate oligomer.
(ii) Polyisocyanate Preferred examples of the polyisocyanate (ii) used in the present invention include 2,4-tolyenediisocyanate, 2,6-tolyenediisocyanate, 1,3- xylenediisocyanate, 1,4-xylenediisocyanate, 1 ,5-naphthalenediisocyanate, 1,6- hexanediisocyanate, isophoronediisocyanate (IPDI), and a mixture thereof. The polyisocyanate is preferably used in an amount ranging from 10 to 40 % by weight based on the total weight of the photopolymerizable urethane acrylate oligomer.
(iii) Acrylate alcohol
Preferred examples of the acrylate alcohol (iii), which comprises at least one (meth)acrylate and hydroxy group, include 2- hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2- hydroxybutyl(meth)acrylate, 2-hydroxyethylacrylate, 2-hydroxypropylacrylate, 2-hydroxy-3-phenyloxypropyl(meth)acrylate, 4-hydroxybutylacrylate, neopentylglycolmono(meth)acrylate, 4-hydroxycyclohexyl(meth)acrylate, 1 ,6- hexanediolmono(meth)acrylate, pentaerythritolpenta(meth)acrylate, dipentaerythritolpenta(meth)acrylate, and a mixture thereof. The acrylate alcohol is preferably used in an amount ranging from 10 to 35 % by weight
based on the total weight of the photopolymerizable urethane acrylate oligomer.
(iv) Urethane reaction catalyst
Preferred examples of the urethane reaction catalyst (iv), which is used in the urethane reaction, include copper naphthenate, cobalt naphthenate, zinc naphthenate, n-butyltinlaurate, dibutyltindilaurate, tristhylamine, 2- methyltriethylenediamide, and a mixture thereof. The urethane reaction catalyst is preferably used in an amount ranging from 0.01 to 1 % by weight based on the total weight of the photopolymerizable urethane acrylate oligomer.
(v) Polymerization inhibitor
Preferred examples of the polymerization inhibitor (v) include hydroquinone, hydroquinone monomethylether, para-benzoquinone, phenothiazine, and a mixture thereof. The polymerization inhibitor is preferably used in an amount ranging from 0.01 to 1 % by weight based on the total weight of the photopolymerizable urethane acrylate oligomer.
Said photopolymerizable urethane acrylate oligomer (A) may be synthesized using above components as follows: A polyisocyanate (ii) is added in a round-bottom flask equipped with a stirrer. While stirring, a part or all of a urethane reaction catalyst (iv) is added and a polyol copolymer (i) is slowly added thereto. The mixture is allowed to react at about 70 to 80°C until the NCO concentration of the resulting product reaches a predetermined level, to obtain a urethane prepolymer. A polymerization inhibitor (v), an acrylate alcohol (iii) and, if necessary, the remaining amount of the urethane reaction catalyst (iv) are slowly added to the flask containing the urethane prepolymer, and the mixture is allowed to react at 800C. The reaction is allowed to terminate after disappearance of an NCO peak at about 2270cm"1 is confirmed by an infrared spectrometer, to obtain a photopolymerizable urethane acrylate oligomer.
(B) Reactive monomer
The reactive monomer (B) used in the present invention which has at least one acrylate group, methacrylate group or vinyl group serves as a diluent to adjust a viscosity of the oligomer component to an appropriate level for working, and thus preferably has a low number average molecular weight of 100 to 300.
Besides at least one acrylate group, methacrylate group or vinyl group, the reactive monomer may contain one or more and various functional groups, preferably 1 to 8 propylene oxide groups (-OC3H6-). In particular, a reactive monomer which can provide a film having a high tensile strength and low curing shrinkage is preferred. Preferred examples thereof include phenoxyethylacrylate, phenoxyethyleneglycolacrylate, phenoxytetraethyleneglycolacrylate, phenoxyhexaethyleneglycolacrylate, isobonylacrylate (IBOA), isobonylmethacrylate, N-vinylpyrrolidone (N-VP), N-vinylcaprolactam (N-VC), acryloyl morpholine (ACMO), bisphenol ethoxylate diacrylate, ethoxylate phenol monoacrylate, polyethyleneglycol 400 diacrylate, tripropyleneglycol diacrylate, trimethyl propane triacrylate (TMPTA), polyethyleneglycol diacrylate, ethyleneoxide-addition triethylpropantriacrylate, pentaerythritol tetraacrylate (PETA), 1 ,4-butanediol diacrylate, 1,6-hexanediol diacrylate, ethoxylated pentaerythritol tetraacrylate, ethoxylated nonylphenol acrylate, 2-phenoxyethyl acrylate, ethoxylated bisphenol A diacrylate, alkoxylated nonylphenol acrylate, alkoxylated trifunctional acrylate ester, metallic diacrylate, trifunctional acrylate ester, trifunctional methacrylate ester, and a mixture thereof.
If needed, a monomer which enhances adhesion strength to a substrate may further used.
The reactive monomer is used in an amount ranging from 5 to 60 % by weight based on the total weight of the coating composition. When the amount is less than 5 % by weight, it may be difficult to lower a viscosity of the oligomer component to a level suitable for working, i.e., a range of 3,000 to 10,000 cps (25 "C), and when more than 60 % by weight, poor properties such as high viscosity, enlargement of particles, unbalanced surface upon curing, and optical losses occur, due to decreases of the curing shrinkage and
thermal stability at high temperature.
(C) Photoinitiator
In the present invention, the photoinitiator (C) is used to help a fast curing speed of a resin itself, in order to keep a pace with optical fiber coating speed of l,500m/min or higher. The photoinitiator forms free radicals by UV energy and attacks double bonds in resins to induce polymerization. Preferred examples thereof include Irgacure #184
(hydroxy cyclohexylphenylketone), Irgacure #907 (2-methyl-l [4- (methylthio)phenyl]-2-morpholino-propan-l-one), Irgacure #500 (hydroxy- ketones and benzophenone), Irgacure #651 (benzildimethylketone), Darocure #1173 (2-hydroxy-2-methyl-l-phenyl-propan-l-one), Darocure TPO (2,4,6- trimethylbenzoyldiphenylphosophine oxide), Darocure CGI#1800 (bisacylphosphineoxide)) and Darocure CGI#1700 (bisacyl phosphine oxide and hydroxycyclohexylphenylketone), which are commercially available from Ciba Geigy Co, and a mixture thereof.
The photoinitiator is used in an amount ranging from 1 to 15 % by weight based on the total weight of the coating composition.
(D) Amine additive
The amine additive, an optional component, is used to prevent a coating composition from polymerization caused by a high temperature or a light before cured, from a hydrogen gas release after cured, and from transmission losses, as well as to provide a fast curing speed. Preferred examples thereof include diallylamine, diisopropylamine, diethylamine, diethylhexylamine, triethylamine, N-methyldiethanolamine, ethanolamine, diethanolamine, and a mixture thereof. The amine additives are preferably used in an amount ranging from 0.01 to 0.5 % by weight based on the total weight of the coating composition.
(E) Other additives - silane-based monomer, stabilizer, or mixture thereof
Further, the photocurable coating composition of the present invention may comprise a silane-based monomer, a stabilizer or a mixture thereof to inhibit decrease of adhesion strength between the coating layer and glass fiber substrate. The silane-based monomer, the stabilizer or the mixture thereof may be used in an amount ranging from 1 to 5 % by weight based on the total weight of the coating composition. When the amount is out of the above scope, lowering of a curing speed may occur.
The silane-based monomer functions to enhance adhesion strength between the coating layer and glass fiber substrate as well as to lower a water absorption ratio of a resin composition. Representative examples of the silane-based monomer include vinyl trimethoxy silane commercially available from Chisso Co. (Japan), vinyl trimethoxy silane from others, vinyl tri(methoxyethoxy)silane, gamma-methacryl oxypropyltrimethoxy silane, gamma-glycid oxypropylmethoxy silane, gamma-aminopropyltriethoxy silane, gamma-mercaptopropyltrimethoxy silane, and a mixture thereof.
Representative examples of the stabilizer, which acts to improve thermal, oxidative and storage stabilities of a coating composition, include Irganox 1010, Irganox 1035, and Irganox 1076, which are commercially available from Ciba Geigy Co, and a mixture thereof.
A method for preparing the inventive photocurable coating composition is as follows:
A photopolymerizable urethane acrylate oligomer (A), a reactive monomer (B), a photoinitiator (C), optionally an amine-additive (D) and other additives (E) are added to a reactor. The mixture is stirred under a temperature of 15 to 500C, a humidity of 60% or less and a homogeneous speed of l,000rpm or higher, by using a dispersion impeller. When the reaction is carried out at a temperature lower than 15°C, the viscosity of the photopolymerizable urethane acrylate oligomer (A) increases, resulting in unsmooth processing, and when the reaction is carried out at a temperature higher than 50°C, the photoinitiator (C) may cause undesirable curing due to the formation of radicals. When the reaction is carried out at a humidity
higher than 60%, bubbles may be generated from a resin composition during a subsequent coating process and a side-reaction that non-reactants react with moistures in air may occur. Further, when the mixture is stirred at a speed lower than l,000rpm, unsatisfactory mixing may be achieved.
The inventive coating composition is used to prepare a coating layer or film, and the coating layer or film has the following characteristics:
If the composition is used to prepare a 10 to 30μm-thick film coated on a glass fiber substrate by curing, the film remains tightly adhered on the glass even after being dipped in 45 to 85°C water for a prolonged time (e.g., at least 60 days). If the composition is used to prepare a lOOμm-thick film coated on a glass fiber substrate by curing, the film has a 2.5% secant modulus of 0.1 to 0.3 kgf/mm2 and an adhesion strength to the glass fiber substrate of 1 to 3 N (Newton). An optical fiber having a 10 to 30μm-thick coating layer can be prepared by coating the inventive coating composition on a glass fiber and curing the coating by light irradiation (exposure to a UV lamp) {see Fig. 1). On curing with a UV-lamp, a D-bulb having a light intensity of 0.5 ~ 3 J/cm2 and a speed of 30 ~ 150fpm may be used. The optical fiber prepared by above method has improved hot water resistance, without causing the photosignal loss or reduction of adhesion strength even when dipped in hot water for a prolonged time. Accordingly, the inventive optical fiber shows improved thermal, mechanical, and chemical stabilities, in particular, no delamination when dipped in 45~85°C water for a prolonged time (e.g., at least 60 days).
The following Examples are intended to further illustrate the present invention without limiting its scope.
Preparation Example 1; Preparation of a photopolymerizable urethane acrylate oligomer (A)
138.32g (0.62 mole) of isophoronediisocyanate (IPDI; Lyondell chemical Co.) and 0.17g of dibutyltindilaurate (Songwon industrial Co.) were added to a 2L round-bottom flask equipped with a stirrer. The mixture was heated to 800C, and 109.03g (0.11 mole) of polytetramethyleneglycol polyol (PTMG; BASF Co.) with a number average molecular weight of 1000 was added thereto. After completion of the addition, the NCO concentration (theoretically 8.67%) of the resulting product was adjusted to 7.5 to 8.5%. In addition, 716.5Og (0.36 mole) of polypropyleneglycol polyol (PPG; Korea Polyol Co.) with a number average molecular weight of 2000 was added thereto. After completion of the addition, the NCO concentration (theoretically 1.07%) of the resulting product was adjusted to 0.7 to 1.0% to obtain a urethane prepolymer. 2.15g of hydroquinonemonomethylether (HQMME; Eastman Co.), 37.96g (0.33 mole) of 2-hydroxyethylacrylate (2- HEA; Nippon shokubai Co.) and O.lg of dibutyltindilaurate were slowly added thereto. The mixture was allowed to react at 800C for 1 hour. The reaction was allowed to terminate after disappearance of an NCO peak at 2270cm'1 is confirmed by an infrared spectrometer, to obtain a photopolymerizable urethane acrylate oligomer. The oligomer obtained above has a number average molecular weight of 23,000g/mol (determined by gel permeation chromatography (GPC)), a viscosity of 14,000cps at 25 °C, and an average urethane bonding number of 4.
Preparation Example 2
121.55g of isophoronediisocyanate (IPDI; Lyondell chemical Co.) and
0.17g of dibutyltindilaurate (Songwon industrial Co.) were added to a 2L round-bottom flask equipped with a stirrer. The mixture was heated to 800C, and 112.13g of polytetramethyleneglycol polyol (PTMG; Hodogaya Co.) with a number average molecular weight of 850 was added thereto. After completion of the addition, the NCO concentration (theoretically 8.97%) of the resulting product was adjusted to 7.5 to 8.5%. In addition, 755.33g of polypropyleneglycol polyol (PPG; Korea Polyol Co.) with a number average
molecular weight of 2000 was added thereto. After completion of the addition, the NCO concentration (theoretically 1.08%) of the resulting product was adjusted to 0.7 to 1.0% to obtain a urethane prepolymer. 2.15g of hydroquinonemonomethylether (HQMME; Eastman Co.), 38.5 Ig of 2- hydroxyethylacrylate (2-HEA; Nippon shokubai Co.) and O. lg of dibutyltindilaurate were slowly added thereto. The mixture was allowed to react at 800C for 1 hour. The reaction was allowed to terminate after disappearance of an NCO peak at 2270cm'1 is confirmed by an infrared spectrometer, to obtain a photopolymerizable urethane acrylate oligomer. The oligomer obtained above has a number average molecular weight of 21,000g/mol (determined by gel permeation chromatography (GPC)), a viscosity of 12,100cps at 25°C, and an average urethane bonding number of 4.
Preparation Example 3
115.24g of isophoronediisocyanate (IPDI; Lyondell chemical Co.) and 0.17g of dibutyltindilaurate (Songwon industrial Co.) were added to a 2L round— bottom flask equipped with a stirrer. The mixture was heated to 80°C, and 102.15g of polytetramethyleneglycol polyol (PTMG; Korea Polyol Co.) with a number average molecular weight of 650 was added thereto. After completion of the addition, the NCO concentration (theoretically 8.97%) of the resulting product was adjusted to 7.5 to 8.5%. In addition, 760.5Og of polypropyleneglycol polyol (PPG; Korea Polyol Co.) with a number average molecular weight of 2000 was added thereto. After completion of the addition, the NCO concentration (theoretically 1.08%) of the resulting product was adjusted to 0.7 to 1.0% to obtain a urethane prepolymer. 2.15g of hydroquinonemonomethylether (HQMME; Eastman Co.), 39.11g of 2- hydroxyethylacrylate (2-HEA; Nippon shokubai Co.) and O.lg of dibutyltindilaurate were slowly added thereto. The mixture was allowed to react at 800C for 1 hour. The reaction was allowed to terminate after disappearance of an NCO peak at 2270cm"1 is confirmed by an infrared spectrometer, to obtain a photopolymerizable urethane acrylate oligomer.
The oligomer obtained above has a number average molecular weight of 21,000g/mol (determined by gel permeation chromatography (GPC)), a viscosity of 12,000cps at 25°C, and an average urethane bonding number of 4.
Comparative Preparation Example 1
150.0g (2 mole) of isopropyldiisocyanate and 0.05g of dibutyltindilaurate were added to a 3L round-bottom flask equipped with a stirrer. The mixture was heated to 800C, and 771.Og (1 mole) of mixed polyether/ester polyol with a number average molecular weight of 2000 was added thereto. After completion of the addition, the NCO concentration (theoretically 0.6%) of the resulting product was adjusted to 0.1 to 0.3% to obtain a urethane prepolymer. 2.13g of hydroquinonemonomethylether (HQMME) and 78.Og (1 mole) of 2-hydroxyethylacrylate were slowly added thereto. The mixture was allowed to react at 80°C for 3 hour. The reaction was allowed to terminate after disappearance of an NCO peak at 2270cm"1 is confirmed by an infrared spectrometer, to obtain a photopolymerizable urethane acrylate oligomer. The oligomer obtained above has a number average molecular weight of 22,000g/mol (determined by gel permeation chromatography (GPC)), a viscosity of 15,200cps at 25 °C, and an average urethane bonding number of 4.
Comparative Preparation Example 2
136.84g of isopropyldiisocyanate and 0.05g of dibutyltindilaurate were added to a 2L round-bottom flask equipped with a stirrer. The mixture was heated to 800C, and 821.86g of polytetramethyleneglycol polyol (PTMG; BASF Co.) with a number average molecular weight of 2000 was added thereto. After completion of the addition, the NCO concentration (theoretically 0.6%) of the resulting product was adjusted to 0.4 to 0.6% to obtain a urethane prepolymer. 2.01g of hydroquinonemonomethylether (HQMME) and 41. Ig of 2-hydroxyethylacrylate were slowly added thereto.
The mixture was allowed to react at 80°C for 3 hour. The reaction was allowed to terminate after disappearance of an NCO peak at 2270cm'1 is confirmed by an infrared spectrometer, to obtain a photopolymerizable urethane acrylate oligomer. The oligomer obtained above has a number average molecular weight of 24,000g/mol (determined by gel permeation chromatography (GPC)), a viscosity of 18,200cps at 25 "C, and an average urethane bonding number of 4.
Examples 1 to 9 and Comparative Examples 1 to 6
Various photocurable coating compositions were obtained by combining each of the photopolymerizable urethane acrylate oligomers prepared in Preparation Examples 1 to 3 and Comparative Preparation Examples 1 and 2 together with other ingredients, in amounts shown in Table 1.
<Table 1>
Experimental Example; Evaluation on properties of photocurable coating compositions
In order to investigate physical properties and hot water resistance of the photocurable coating compositions prepared in Examples 1 to 9 and Comparative Examples 1 to 6, a viscosity, and a tensile strength, an adhesion strength to a glass fiber substrate, a glass transition temperature and a hot water resistance after cured were measured for the compositions as follows, and the results were shown in Table 2.
(1) Viscosity
A viscosity of a composition sample was measured in a torque ranging from 50 to 90% by using a Brookfield DV III+ viscometer, #31 spindle, according to ASTM D-2196.
(2) Tensile strength after cured: 2.5% secant modulus
A composition sample was coated on a 20x20 cm glass plate by using a bar coater having a fixed thickness of 7 to 1 Omil. After being placed into a fixing frame, the coated film was cured under a nitrogen gas (401pm) by using a 600W and 9mm D-bulb (model DRSl 0/12-QN; Fusion Co.) with a light intensity of 2.5 J/cm2 and a speed of 30fpm to obtain a cured lOOμm-thick film. The cured film was separated from the glass plate and cut into a 13mm- width film by using a JDC cutter. The cut film was equilibrated in a desiccator of 230C and RH 50% for one day. Then, 2.5% secant modulus was measured by pulling the film at a speed of 25mm/min by using 4443 UTM (Instron Co.).
(3) Adhesion strength to a glass fiber substrate after cured
A composition sample was coated on a 20x20 cm glass plate by using a bar coater having a fixed thickness of 5mil. Then, a secondary coating was coated in a thickness of lOmil thereon. After being placed into a fixing frame, the coated film was cured under a nitrogen gas (401pm) by using a 600W and
9mm D-bulb (model DRS10/12-QN; Fusion Co.) with a light intensity of 2.5 J/cm2 and a speed of 30fpm to obtain a cured lOOμm-thick film. The cured film was separated from the glass plate and cut into a 20mm-width film by using a JDC cutter. The cut film was equilibrated in a desiccator of 23°C and RH 50% for one day. Then, a degree of adhesion strength to a glass fiber substrate was measured by pulling the film at an angle of 90° and a speed of 25mm/min by using 4443 UTM (Instron Co.).
(4) Glass transition temperature (Tg) A composition sample was coated on a 20x20 cm glass plate by using a bar coater. After being placed into a fixing frame, the coated film was cured under a nitrogen gas (401pm) by using a 600W and 9mm D-bulb (model DRS10/12-QN; Fusion Co.) with a light intensity of 2.5 J/cm2 and a speed of 30fpm to obtain a cured 600μm-thick film. The cured film was cut into a 15mm-length and 10mm- width film. The cut film was placed in DMTA IV (Dynamic mechanical temperature analysis; Rheometry) and geometrical values for the film were input thereto. The measurement was carried out by cooling the film to about -100°C and warming it to about 60°C by 2°C/min. The test frequency was 1.0 radian/sec. A glass transition temperature was calculated from a tan delta peak in the graph obtained.
(5) Hot water resistance
A glass fiber having a diameter of 125μm was passed through a syringe (2 mL) containing a coating composition and the coated glass fiber was UV- cured, as shown in Fig. 1. The UV-curing was carried out under a light intensity of 1.0 J/cm2 (UVA region) and a speed of 150fpm using a D-bulb of a Fusion UV apparatus. The thickness of the coating layer was in the range of 10 to 30μm.
In order to investigate hot water resistance of the coating layer, the coated and cured fiber was dipped in each of 45, 65 and 85°C water. After 10, 30 and 60 days from the dipping, the fiber was pulled out from water, dried at room temperature for 10 minutes and cut into lOcm-long fragments. Then,
for ten fiber fragments, an interface between the glass fiber and the coating layer was observed by an optical microscope (200-fold magnification), to count the number of droplet penetrated at the interface.
<Table 2>
As shown in Table 2, the coating layers obtained from the compositions of Examples 1 to 9 exhibited high hot water resistance and adhesion strength to the glass fiber substrate even after being dipped in hot water for a prolonged time, while those obtained from the compositions of Comparative Examples 1 to 6, a phenomenon (delamination) separated from the glass fiber substrate with the dipping time.
Further, comparing the results derived from Examples 1 to 9, it is confirmed that increase of the amount of the photopolymerizable urethane acrylate oligomer leads to lowering of a glass transition temperature which provides an effect for preventing increase of optical loss at low temperature in the final optical fiber, increase of adhesion strength to the glass fiber substrate, and increase of secant modulus within 0.2 kgf/mm2 or less.
While the invention has been described with respect to the above specific embodiments, it should be recognized that various modifications and changes may be made to the invention by those skilled in the art which also fall within the scope of the invention as defined by the appended claims.
Claims
1. A photocurable coating composition comprising:
(A) 30 to 90 % by weight of a photopolymerizable urethane aery late oligomer which is synthesized using a polyol copolymer, a polyisocyanate, an acrylate alcohol, a urethane reaction catalyst, and a polymerization inhibitor;
(B) 5 to 60 % by weight of a reactive monomer containing at least one acrylate, methacrylate, or vinyl group; and
(C) 1 to 15 % by weight of a photoinitiator.
2. The composition of claim 1, wherein in the component (A), the polyol copolymer, the polyisocyanate, the acrylate alcohol, the urethane reaction catalyst and the polymerization inhibitor are used in amounts ranging from 30 to 75 % by weight, 10 to 40 % by weight, 10 to 35 % by weight, 0.01 to 1 % by weight and 0.01 to 1 % by weight, respectively, based on the total weight of the photopolymerizable urethane acrylate oligomer.
3. The composition of claim 1, wherein the photopolymerizable urethane acrylate oligomer has a number average molecular weight ranging from 5,000 to 50,000.
4. The composition of claim 1, wherein the photopolymerizable urethane acrylate oligomer is composed of 10:90 to 30:70 weight ratio of poly ether polyol and polyester polyol.
5. The composition of claim 1, wherein the polyol copolymer has a number average molecular weight ranging from 100 to 10,000 and contains a repeating unit Of-CH2CH2O- or -CH2CH(CH2CH3)O-.
6. The composition of claim 1, wherein the reactive monomer has 1 to 8 propylene oxide (-OC3H6-) functional groups.
7. The composition of claim 1, wherein the reactive monomer is selected from the group consisting of phenoxyethylacrylate, phenoxyethyleneglycolacrylate, phenoxytetraethyleneglycolacrylate, phenoxyhexaethyleneglycolacrylate, isobonylacrylate, isobonylmethacrylate, N-vinylpyrrolidone, N-vinylcaprolactam, acryloyl morpholine, bisphenol ethoxylate diacrylate, ethoxylate phenol monoacrylate, polyethyleneglycol 400 diacrylate, tripropyleneglycol diacrylate, trimethyl propane triacrylate, polyethyleneglycol diacrylate, ethyleneoxide-addition triethylpropantriacrylate, pentaerythritol tetraacrylate, 1 ,4-butanediol diacrylate, 1 ,6-hexanediol diacrylate, ethoxylated pentaerythritol tetraacrylate, ethoxylated nonylphenol acrylate, 2-phenoxyethyl acrylate, ethoxylated bisphenol A diacrylate, alkoxylated nonylphenol acrylate, alkoxylated trifunctional acrylate ester, metallic diacrylate, trifunctional acrylate ester, trifunctional methacrylate ester, and a mixture thereof.
8. The composition of claim 1, which further comprises 0.01 to 0.5 % by weight of an amine additive, or 1 to 5 % by weight of a silane-based monomer, a stabilizer or a mixture thereof, or both thereof.
9. The composition of claim 8, wherein the amine additive is selected from the group consisting of diallylamine, diisopropylamine, diethylamine, diethylhexylamine, triethylamine, N-methyldiethanolamine, ethanolamine, diethanolamine, and a mixture thereof.
10. The composition of claim 1, wherein the composition is used to prepare a 10 to 30 μm-thick film coated on a glass fiber substrate by curing, and the film remained tightly adhered on the glass after being dipped in 45 to 850C water for at least 60 days.
11. The composition of claim 1 , wherein the composition is used to prepare a 100 μm-thick film coated on a glass fiber substrate by curing, the film having a 2.5% secant modulus ranging from 0.1 to 0.3 kgf7mm2.
12. The composition of claim 1, wherein the composition is used to prepare a 100 μm-thick film coated on a glass fiber substrate by curing, and the film having an adhesion strength to the glass of 1 to 3 N (Newton).
13. An optical fiber comprising a coating layer which is obtained by coating the photocurable coating composition of claim 1 on a glass fiber and curing the coating.
14. The optical fiber of claim 13, wherein the coating layer has a thickness ranging from 10 to 30 μm.
15. The optical fiber of claim 14, wherein the coating layer remains tightly adhered on the glass after being dipped in 45 to 85°C water for at least 60 days.
16. The optical fiber of claim 13, wherein the curing of the photocurable coating composition is performed by exposure to a D-bulb of a UV-lamp having a light intensity of 0.5 ~ 3 J/cm2 and a speed of 30 ~ 150fpm.
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TWI425060B (en) * | 2010-01-25 | 2014-02-01 | Bridgestone Corp | A photopolymerizable composition and a functional panel using the same |
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EP2995656A1 (en) * | 2014-09-12 | 2016-03-16 | Nidek Co., Ltd | Composition for hard coat |
US20170247589A1 (en) * | 2014-09-05 | 2017-08-31 | 3M Innovative Properties Company | Heat conformable curable adhesive films |
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KR101501499B1 (en) * | 2014-04-07 | 2015-03-12 | 윤학중 | Ultraviolet Curable Resin Composition |
CN106478862A (en) * | 2016-10-24 | 2017-03-08 | 中科院合肥技术创新工程院 | The quick Actinochemical synthesis of polymer and the reaction unit for the method |
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EP1209132A1 (en) * | 2000-11-22 | 2002-05-29 | Dsm N.V. | Coated optical fibers, primary coating composition, method for curing, as well as an assembly and a method for measuring |
WO2002042383A1 (en) * | 2000-11-22 | 2002-05-30 | Dsm N.V. | Radiation curable compositions |
KR20030066762A (en) * | 2000-12-29 | 2003-08-09 | 디에스엠 아이피 어셋츠 비.브이. | Non-crystal-forming oligomers for use in radiation-curable fiber optic coatings |
KR100926714B1 (en) * | 2002-05-10 | 2009-11-17 | 디아이씨 가부시끼가이샤 | Resin composition for optical fiber coating and coated optical fiber and optical fiber unit using the same |
KR100579007B1 (en) * | 2003-08-13 | 2006-05-12 | 주식회사 루밴틱스 | Photocurable and antistatic resin composition for optical fiber coating |
KR100596492B1 (en) * | 2003-11-28 | 2006-07-04 | 주식회사 루밴틱스 | Photocurable polymeric resin composition for optical fiber in-line coating |
KR100793597B1 (en) * | 2005-06-02 | 2008-01-10 | 주식회사 엘지화학 | Coating composition for ultraviolet-curable film type and film prepared from it |
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2008
- 2008-07-16 KR KR1020080069201A patent/KR101018357B1/en active IP Right Grant
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2009
- 2009-07-14 WO PCT/KR2009/003853 patent/WO2010008174A2/en active Application Filing
- 2009-07-14 CN CN2009801359837A patent/CN102159656A/en active Pending
- 2009-07-14 EP EP09798077A patent/EP2310464A4/en not_active Withdrawn
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US8859634B2 (en) * | 2007-12-27 | 2014-10-14 | Bridgestone Corporation | Adherent resin composition |
US20100286301A1 (en) * | 2007-12-27 | 2010-11-11 | Bridgestone Corporation | Adherent resin composition |
CN102190915A (en) * | 2010-01-25 | 2011-09-21 | 株式会社普利司通 | Light polymerization composition and functional panel having the same |
TWI425060B (en) * | 2010-01-25 | 2014-02-01 | Bridgestone Corp | A photopolymerizable composition and a functional panel using the same |
CN102190915B (en) * | 2010-01-25 | 2014-06-25 | 株式会社普利司通 | Light polymerization composition and functional panel having the same |
US9708491B2 (en) * | 2014-06-04 | 2017-07-18 | Corning Incorporated | Optical fiber coating and composition |
US20150353757A1 (en) * | 2014-06-04 | 2015-12-10 | Corning Incorporated | Optical fiber coating and composition |
US10377915B2 (en) | 2014-06-04 | 2019-08-13 | Corning Incorporated | Optical fiber coating and composition |
US20170247589A1 (en) * | 2014-09-05 | 2017-08-31 | 3M Innovative Properties Company | Heat conformable curable adhesive films |
US10982122B2 (en) * | 2014-09-05 | 2021-04-20 | 3M Innovative Properties Company | Heat conformable curable adhesive films |
US20160075908A1 (en) * | 2014-09-12 | 2016-03-17 | Nidek Co., Ltd. | Composition for hard coat, dyed resin body with hard coat, and method for producing dyed resin body with hard coat |
US9951246B2 (en) | 2014-09-12 | 2018-04-24 | Nidek Co., Ltd. | Composition for hard coat, dyed resin body with hard coat, and method for producing dyed resin body with hard coat |
EP2995656A1 (en) * | 2014-09-12 | 2016-03-16 | Nidek Co., Ltd | Composition for hard coat |
Also Published As
Publication number | Publication date |
---|---|
KR101018357B1 (en) | 2011-03-04 |
WO2010008174A3 (en) | 2010-04-22 |
EP2310464A4 (en) | 2013-01-23 |
KR20100008633A (en) | 2010-01-26 |
CN102159656A (en) | 2011-08-17 |
EP2310464A2 (en) | 2011-04-20 |
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