Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/10—Metal compounds
• • 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
  • C08G79/00—Macromolecular compounds obtained by reactions forming a linkage containing atoms other than silicon, sulfur, nitrogen, oxygen, and carbon with or without the latter elements in the main chain of the macromolecule
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
  • B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0091—Complexes with metal-heteroatom-bonds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L85/00—Compositions of macromolecular compounds obtained by reactions forming a linkage in the main chain of the macromolecule containing atoms other than silicon, sulfur, nitrogen, oxygen and carbon; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/56—Organo-metallic compounds, i.e. organic compounds containing a metal-to-carbon bond
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles

Definitions

• the present invention relates to novel compositions which can be formed into metal oxide films having high refractive indices.
• the compositions are useful for forming solid-state devices such as flat panel displays, optical sensors, integrated optical circuits, and light-emitting diodes.
• certain metal oxides most notably those of titanium and zirconium, possess excellent optical clarity when applied as thin films and exhibit refractive indices of 2.0 or more at visible wavelengths. They, unfortunately, must be deposited by expensive and inefficient methods such as evaporation or sputtering, and then can only be applied as thin films (less than 1 ⁇ m in thickness) whereas device makers are often seeking films of several microns to several tens of microns in thickness. Moreover, the deposited metal oxide coatings are brittle and may not adhere well to device surfaces without high-temperature annealing, which may degrade device operation.
• sol-gel coating method has been used to deposit high index metal oxide coatings from solution.
• the coatings tend to be brittle and subject to cracking and require long, complicated curing schedules.
• Sol-gel coating solutions also have limited pot life, making the method difficult to practice on a commercial scale.
• the sol-gel method has been combined with conventional polymer chemistry to prepare inorganic-organic hybrid coatings in which the metal oxide phase, formed by in situ hydrolysis and condensation of a metal alkoxide, is chemically bonded to an organic polymer phase to obtain materials with greater toughness and durability.
• sol-gel compositions are still prone to the pot life problems associated with sol-gel compositions and lend themselves best to silicon dioxide incorporation, which does not promote a high refractive index.
• Inorganic-organic hybrid coatings have also been prepared by dispersing nanosized (1 to 50 nm in diameter) metal oxide particles in a polymer vehicle to produce transparent film compositions.
• the refractive indices of these compositions are largely restricted to the range of 1.55 to 1.70 unless very high metal oxide loadings (80%) are utilized.
• preparation of the coatings requires many steps, including particle synthesis and purification, surface treatment, and dispersion, often under a non- ambient environment.
• the present invention fills this need by broadly providing novel coating compositions for use in optical device applications.
• compositions comprise an organometallic oligomer and an organic polymer or oligomer dispersed or dissolved in a solvent system.
• the organometallic oligomer can be linear or branched and will thermally decompose to a high refractive index metal oxide.
• Preferred organometallic oligomers comprise monomers having the structure
• n is greater than 2 and more preferably 3-10;
• each M is individually selected from the group consisting of Groups 3-5 and 13-15 metals from the Periodic table of elements (more preferably Group 4 and even more preferably titanium or zirconium) other than silicon and having a combining valence of greater than +2; and
• each R 1 is an organic moiety covalently bonded or coordinate-covalently bonded to M.
• Preferred R 1 groups include those which form a —CH 2 —O—M bond (where M is the metal atom as discussed above) such as those selected from the group consisting of alkoxys (preferably C 1 -C 12 , and more preferably C 1 -C 8 ), alkyloxyalkoxys (preferably C 1 -C 12 , and more preferably C 1 -C 8 ), beta-diketones, beta-diketonates, and alkanolamines.
• preferred R 1 groups have a formula selected from the group consisting of
• * represents the covalent bond or coordinate-covalent bond with M
• each R 2 is individually selected from the group consisting of alkyls (preferably C 1 -C 12 , and more preferably C 1 -C 8 , with methyl and ethyl being the most preferred), haloalkyls (preferably C 1 -C 12 , and more preferably C 1 -C 8 ; preferably fluoroalkyls with trifluoromethyl being the most preferred), and —OR 3 , where R 3 is selected from the group consisting of hydrogen, alkyls (preferably C 1 -C 12 , and more preferably C 1 -C 8 ), aryls (preferably C 6 -C 18 , and more preferably C 6 -C 12 ), and alkylaryls (preferably C 1 -C 12 , and more preferably C 1 -C 8 for the alkyl component and preferably C 6 -C 18 , and more preferably C 6 -C 12 for the aryl component); and
• * represents the covalent bond or coordinate-covalent bond with M
• each R 4 is individually selected from the group consisting of hydrogen, alkyls (preferably C 1 -C 12 , and more preferably C 1 -C 8 ), hydroxyalkyls (preferably C 1 -C 12 , and more preferably C 1 -C 8 ), aryls (preferably C 6 -C 18 , and more preferably C 6 -C 12 ), and alkylaryls (preferably C 1 -C 12 , and more preferably C 1 -C 8 for the alkyl component and preferably C 6 -C 18 , and more preferably C 6 -C 12 for the aryl component), with at least one R 4 being selected from the group consisting of hydrogen, alkyls, (preferably C 1 -C 12 , and more preferably C 1 -C 8 ) and hydroxyalkyls (preferably C 1 -C 12 , and more preferably C 1 -C 8 ); and
• R 5 is selected from the group consisting of hydrogen and methyl.
• R 4 groups include 2-hydroxyethyl and 2-hydroxypropyl. In these instances, the R 4 groups may optionally form coordinate-covalent bonds with the same or different metal atoms.
• the organometallic oligomer is preferably present in the composition at a level of at least about 15% by weight, preferably from about 15-35% by weight, and more preferably from about 24-35% by weight, based upon the total weight of the composition taken as 100% by weight.
• the organic polymer or oligomer can be either branched or linear.
• An organic oligomer rather than an organic polymer would typically be used, but the scope of this invention is intended to include both so long as the organic polymer or oligomer comprises a functional group (and preferably three such functional groups) capable of forming covalent or coordinate-covalent bonds with the organometallic oligomer.
• the functional group can be present within the backbone of the organic polymer or oligomer, or it can be present as a group pendantly attached (either directly or through a linking group) to the polymer backbone, provided the functional group meets the other requirements discussed herein.
• Preferred functional groups on the organic polymer or oligomer include those selected from the group consisting of —OH, —SH, and chelating moieties.
• Preferred chelating moieties include those selected from the group consisting of
• m is 1 or 2;
• each R 6 is individually selected from the group consisting of hydrogen and methyl groups
• each R 7 is individually selected from the group consisting of hydrogen and alkyls (preferably C 1 -C 12 , more preferably C 1 -C 8 , and even more preferably methyl).
• Particularly preferred organic polymers or oligomers include those selected from the group consisting of poly(styrene-co-allyl alcohol), poly(ethylene glycol), glycerol ethoxylate, pentaerythritol ethoxylate, pentaerythritol propoxylate, and combinations thereof.
• the organic polymer or oligomer is preferably present in the composition at a level of at least about 3% by weight, preferably from about 3-35% by weight, and more preferably from about 3-20% by weight, based upon the total weight of the composition taken as 100% by weight.
• the organic polymer or oligomer preferably has a weight-average molecular weight of at least about 150 g/mol, preferably at least about 500 g/mol, and more preferably from about 1500-2500 g/mol.
• Suitable solvent systems include most organic solvents such as those selected from the group consisting of alcohols, glycol ethers, esters, aromatic solvents, ketones, ethers, and mixtures thereof. Particularly preferred solvents are ethyl lactate, ethylene glycol ethers, and propylene glycol ethers (e.g., 1-propoxy-2-propanol).
• the solvent system is preferably present in the composition at a level of at least about 10% by weight, preferably from about 10-35% by weight, and more preferably from about 10-28% by weight, based upon the total weight of the composition taken as 100% by weight.
• compositions can include other solvent-soluble ingredients to modify the optical or physical properties of the coatings formed from the compositions.
• the compositions can include other organic polymers and resins, low molecular weight (less than about 500 g/mol) organic compounds such as dyes, surfactants, and chelating agents (e.g., alkanolamines), and non-polymeric metal chelates such as metal alkoxides or metal acetylacetonates.
• compositions are prepared by dissolving/dispersing the organometallic oligomer and organic polymer or oligomer in the solvent system. This can be done simultaneously, or it can be carried out in two separate vessels followed by combining of the two dispersions or solutions. Any optional ingredients are added in a similar manner.
• the total solids content in the composition can vary from about 1-50% by weight, and more preferably from about 10-40% by weight, based upon the total weight of the composition taken as 100% by weight.
• compositions are applied to a substrate by any known method to form a coating layer or film thereon. Suitable coating techniques include dip coating, draw- down coating, or spray coating. A preferred method involves spin coating the composition onto the substrate at a rate of from about 500-4000 rpm (preferably from about 1000-3000 rpm) for a time period of from about 30-90 seconds to obtain uniform films. Substrates to which the coatings can be applied include flat panel displays, optical sensors, integrated optical circuits, and light-emitting diodes.
• the applied coatings are preferably first baked at low temperatures (e.g., less than about 130° C., preferably from about 60-130° C., and more preferably from about 100-130° C.) for a time period of from about 1-10 minutes to remove the casting solvents.
• low temperatures e.g., less than about 130° C., preferably from about 60-130° C., and more preferably from about 100-130° C.
• the coating is then baked at temperatures of at least about 150° C., and more preferably from about 150-300° C. for a time period of at least about 3 minutes (preferably at least about 5 minutes). Baking at the curing temperature for longer than 5 minutes will produce further small reductions in film thickness and small increases in refractive index.
• the film is heated to a temperature of at least about 300° C. for a time period of from about 5-10 minutes in order to thermally decompose essentially all (i.e., at least about 95% by weight, and preferably at least about 99% by weight) of the organic polymer or oligomer so that extremely high metal oxide content (at least about 95% by weight metal oxide) films are formed.
• This high-temperature baking can be carried out after a hybrid conversion bake step as discussed above, or in lieu of such a bake step.
• the baking processes are conducted preferably on a hot plate-style baking apparatus, though oven baking may be applied to obtain equivalent results.
• the initial drying bake may not be necessary if the final curing process is conducted in such a way that rapid evolution of the solvents and curing by-products is not allowed to disrupt the film quality. For example, a ramped bake beginning at low temperatures and then gradually increasing to the range of 150-300° C. can give acceptable results.
• the choice of final bake temperature depends mainly upon the curing rate that is desired. If curing times of less than 5 minutes are desired, then final baking should be conducted at temperatures greater than about 200° C., and more preferably greater than about 225° C.
• the curing process is preferably carried out in air or in an atmosphere where moisture is present to facilitate complete conversion to metal oxide.
• the curing process can also be aided by exposure of the coating to ultraviolet radiation, preferably in a wavelength range of from about 200-400 nm. The exposure process can be applied separately or in conjunction with a thermal curing process.
• Cured coatings prepared according to the instant invention will have superior properties, even at final thicknesses of greater than 1 ⁇ m.
• the cured coatings or films will have a refractive index of at least about 1.65, more preferably at least about 1.70, and even more preferably from about 1.75-2.00, at wavelengths of about 633 nm and thicknesses of about 0.5 ⁇ m or about 1 ⁇ m.
• cured coatings or films having a thickness of about 0.5 ⁇ m or about 1 ⁇ m will have a percent transmittance of at least about 80%, preferably at least about 90%, and even more preferably least about 95% at wavelengths of from about 633 nm.
• the curing process will yield films having a metal oxide content of from about 25-80% by weight, more preferably from about 25-75% by weight, and even more preferably from about 35-75% by weight, based upon the total weight of the cured film or layer taken as 100% by weight.
• a metal oxide content of from about 25-80% by weight, more preferably from about 25-75% by weight, and even more preferably from about 35-75% by weight, based upon the total weight of the cured film or layer taken as 100% by weight.
• a series of hybrid coatings were prepared by first reacting poly(dibutyltitanate) with ethyl acetoacetate to form a beta-diketonate-chelated organometallic oligomer and then combining this product in solution with different proportions of poly(styrene-co-allyl alcohol) as the organic oligomer.
• the coating solutions were applied onto quartz and silicon substrates by spin-coating, soft-baked on a 130° C. hot plate for 120 seconds, and then cured by baking on a 225° C. hot plate for 10 minutes. This cycle was repeated for some of the compositions to increase film thickness.
• the thickness of each resulting film was measured with an ellipsometer (633-nm light source) or by profilometry, and coating transparency (reported as percent transmission at 633 nm) was measured using a UV-visible spectrophotometer with no corrections for scattering or reflective losses.
• the refractive index of each coating was determined with the aid of a variable-angle scanning ellipsometer (VASE). The results are summarized in Table 2. TABLE 2 Property Ex. 1 Ex. 2 Ex.
• a hybrid coating composition resembling that in Example 4 was prepared but, in this instance, poly(styrene-co-allyl alcohol) [SAA101] was first reacted with t-butyl acetoacetate to esterify a portion of the alcohol groups on the polymer, thus creating acetoacetic ester pendant groups that could form chelating bonds with the organometallic oligomer.
• poly(styrene-co-allyl alcohol) [SAA101] was first reacted with t-butyl acetoacetate to esterify a portion of the alcohol groups on the polymer, thus creating acetoacetic ester pendant groups that could form chelating bonds with the organometallic oligomer.
• a freestanding thick film was prepared by casting the coating mixture onto the bottom of a polypropylene beaker and air-drying for 15 minutes, followed by hot blow drying for another 5 minutes. The coating was then peeled from the plastic surface. The film had a light yellow color and was brittle to touch.
• the purpose of this example was to demonstrate how exposure to ultraviolet radiation can effect the conversion of the organometallic oligomer used in the new compositions to the final metal oxide component.
• Four silicon wafers were coated with an ethyl lactate solution of poly(butyltitanate) to which had been added two equivalents of ethyl acetoacetate per equivalent of titanium to form a chelated organotitanium polymer product.
• the coated wafers were soft-baked on a hot plate and then hard-baked at 205° C. for 60 seconds to partially cure the organotitanium polymer.
• the respective average film thicknesses for the four wafers at that point was 1266 ⁇ as determined by ellipsometry.
• Coatings were prepared by first reacting poly(dibutyltitanate) with ethyl acetoacetate to form a beta-diketonate-chelated organometallic oligomer and then combining this product in solution with one of two different organic oligomers.
• the poly(dibutyltitanate) was weighed into a 500-ml closed container, followed by addition of the propylene glycol n-propyl ether. The contents were stirred until a clear, homogeneous solution was obtained. Next, over a period of 2 hours, the ethyl acetoacetate was added through a dropping funnel into the solution while constant stirring was carried out. The contents were allowed to stir overnight after completing the addition to yield the organometallic oligomer solution.

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polymers With Sulfur, Phosphorus Or Metals In The Main Chain (AREA)
• Paints Or Removers (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Surface Treatment Of Optical Elements (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Laminated Bodies (AREA)

Priority Applications (8)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

Family

ID=32776077

Family Applications (2)

Family Applications After (1)

Country Status (7)

Cited By (11)

Families Citing this family (13)

Citations (11)

Family Cites Families (11)

• 2004
  • 2004-01-15 US US10/758,503 patent/US20040171743A1/en not_active Abandoned
  • 2004-01-16 EP EP04703073.9A patent/EP1590100B1/fr not_active Expired - Lifetime
  • 2004-01-16 CN CN2004800059194A patent/CN1756606B/zh not_active Expired - Fee Related
  • 2004-01-16 WO PCT/US2004/001480 patent/WO2004065428A2/fr active Search and Examination
  • 2004-01-16 JP JP2006501060A patent/JP4768596B2/ja not_active Expired - Fee Related
  • 2004-01-16 KR KR1020057013417A patent/KR20050120626A/ko not_active Application Discontinuation
  • 2004-01-20 TW TW093101504A patent/TWI341316B/zh not_active IP Right Cessation
• 2005
  • 2005-10-07 US US11/246,399 patent/US7803458B2/en active Active

Patent Citations (11)

Also Published As

Similar Documents

Legal Events