Epoxy-modified, two-part acrylic structural adhesives are disclosed. These adhesives are not inhibited by oxygen. Representative embodiments include 2-part acrylic structural adhesives comprising,

Acrylic structural adhesives are extensively used for providing structural strength-imparting bonds to joined metal and or polymer materials. Acrylic structural adhesives are useful for bonding of metal parts in place of welding or mechanical fastening techniques. The structural requirements include high bond strength and good failure mode. A typical method to measure bond strength is the T-peel test. One prevalent use for acrylic structural adhesives is in forming hem flanges in automotive body panels and doors. Exemplary conventional acrylic structural adhesives and methods for using acrylic structural adhesives are disclosed in the following U.S. Patents:
U.S. Pat. No. 6,180,199 entitled Beaded Adhesive And Hem Flanged Part Made Therefrom;
U.S. Pat. No. 6,074,506 entitled Method Of Bonding Using Non-Compressible Beads;
U.S. Pat. No. 5,932,638 entitled Free, Radical Polymerizable Compositions Including Para-Halogenated Aniline Derivatives;
U.S. Pat. No. 5,783,298 entitled Adhesive Mixture With Non-Compressible Beads Therein
U.S. Pat. No. 5,710,235 entitled Olefinic And Urethane-Terminated Ester Polyalkadiene;
U.S. Pat. No. 5,641,834 entitled Modified Polyalkadiene-Containing Compositions; and
U.S. Pat. No. 5,632,413 entitled Adhesive Bonding Apparatus And Method Using Non-Compressible Beads.
Conventional acrylic structural adhesives typically comprise a mixture of one or more olefinic reactive monomers such as methyl methacrylate and methacrylic acid, toughener(s) and redox initiator system. The toughener(s), which may or may not be reactive, or polymerizable with the reactive monomers. Reactive polymers such as unsaturated polyesters, acrylourethane prepolymers may used to grafting onto or crosslink the initiated monomers during polymerization. In addition, fully formulated acrylic structural adhesives typically contain other additives for improving adhesion to substrate materials, environmental resistance, impact strength, flexibility, heat resistance, and the like. Epoxy resins impart improved heat resistance.
U.S. Pat. No. 5,932,638 discloses a structural adhesive which utilizes a redox catalyst system that includes certain para-halogenated aniline reducing agents. U.S. Pat. No. 4,769,419 (xe2x80x9cthe ""419 patentxe2x80x9d), incorporated herein by reference, discloses structural adhesive compositions for metal-metal bonding applications. The adhesives include as tougheners olefinic terminated liquid rubbers which are reacted with monoisocyanate compounds. These tougheners are urethane modified olefinic-termninated liquid elastomer produced from a carboxylic acid-terminated alkadiene or, alternatively, as isocyanate-capped methacrylate-terminated polyalkadiene produced from a carboxylic acid-terminated polyalkadiene. The ""419 patent further describes acrylic adhesives with olefinic monomer, olefinic urethane reaction product of an isocyanate-functional prepolymer and a hydroxy-functional monomer, phosphorus-containing compounds, an oxidizing agent and a free radical source.
U.S. Pat. No. 5,641,834 and U.S. Pat. No. 5,710,235, both incorporated herein by reference, disclose adhesives that include as tougheners an olefinic-terminated polyalkadiene that includes carboxy ester linking groups and at least one nascent secondary hydroxyl group that is capped with a monoisocyanate. These tougheners represented by the formulae for polymer A or polymer B in claim 1 are referred to herein as xe2x80x9colefinic-terminated liquid elastomer produced from a hydroxyl-terminated polyalkadienexe2x80x9d or, alternatively, as xe2x80x9cisocyanate-capped methacrylate-terminated polyalkadiene produced from a hydroxyl-terminated polyalkadienexe2x80x9d. The composition also includes a free radical-polymerizable monomer such as an olefinic: monomer and, optionally, a second polymeric material. In a preferred embodiment the composition is an adhesive that also includes a phosphorus-containing compound and an ambient temperature-active redox catalyst.
U.S. Pat. No. 5,728,759 (xe2x80x9cthe ""759 patentxe2x80x9d) discloses non-structural waterbased pressure sensitive adhesives methods of preparation including an adhesive entity, a tackifier resin, a plasticizer, stabilizer, curing entity and optional additives. Objects of the ""759 patent include providing masking tapes that do not freeze to an automobile body or window on exposure of the tapes to relatively high temperatures while in contact with such surfaces. Elastomeric block copolymers usable in the adhesive entity include block copolymers xe2x80x9cEUROPRENE.TM. Sol T 193Axe2x80x9d from Enichem AMERICAS.
U.S. Pat. No. 5,500,293 is directed to a non-structural adhesive composition suitable for use in an insulating tape having improved plasticizer resistance, including from about 13% to about 42% of a polyisoprene homopolymer, from about 13% to about 42% of a styrene-isoprene-styrene copolymer, and from about 25% to about 55% of an aliphatic tackifying agent. The styrene-isoprene-styrene copolymers disclosed include EUROPRENE.TM.
Huang, Righettini and Dennis disclose in U.S. Pat. No. 6,225,408 as the curable adhesive portion a mixture of 10-90% by weight of at least one free radical-polymerizable monomer, optional adhesion promoter, a primary toughener with a weight average molecular weight (Mw) less than about 18,000 and an auxiliary toughener with a Mw greater than about 18,000.
Peel strength and failure mode of the current acrylic structural adhesives leaves room for improvement. In investigating different principal methacrylic ester monomers from among the myriad methacrylates, many are disqualified due to objectionable odor or lower T-peel strength on electrogalvanized steel. A state of the art epoxy modified acrylic based upon tetrahydrofurfuryl methacrylate yields 39-41 pounds per linear inch T-Peel on electrogalvanized steel. Substitution of certain alcohols in the ester moiety of the methacrylate esterification lead to surprising improvements in T-peel strength, and these monomers providing improved T-Peel do not exhibit objectionable odor. In another aspect, it was discovered that conventional acrylic structural adhesives containing an epoxy curative in a particular mix ratio limiting the epoxy resin content exhibited significantly improved T-peel strength.
In one aspect, the invention resides in an epoxy-modified two-part acrylic structural adhesive characterized by improved T-peel strength, in that the wt. percent of epoxy resin based on the weight of parts A and B of the adhesive is in a range of from 3% to 6%. These adhesives are not inhibited by oxygen. In a 2-pack dispensing system, where parts A and B are mixed in a nozzle equipped with a static mixer, the parts A and B part are combined in a mix ratio of 6:1-14:1 biy volume, preferably from 8:1 to 12:1 and most preferably 9:1-11:1.
In another aspect, the invention is a 2-part acrylic structural adhesive exhibiting improved T-peel strength on galvanized steel and rapid ambient curing via radical polymerization,
(A) in a first package from about 10 to about 90 percent by weight of at least one methacrylate selected from the groups 1) and 2)
1) C3-C10 alkyl, monosubstituted-, C1-C6 alkyl disubstituted-, C1-C4 alkyl tri-substituted, and C1-C4 alkyl tetra-substituted cyclohexyl methacrylate, wherein the substituents are in either the 3, 4, and/or 5 ring position and 2) linear or branched C4-C10 branched alkyl methacrylates; and
(2) from about 10 to about 80 percent by weight of a toughener,
(3) adhesion promotor;
(B) in a second package, a bonding activator, and optional epoxy resin.
An exemplary preferred epoxy-modified two-part acrylic structural adhesive contains about 3 to about 6% by wt. of epoxy resin, which is contained in the B-side.
Comprises:
in the A-side
(a) 10-90, preferably 20-70, weight percent of an olefinic monomer selected from the group consisting of (meth)acrylic acid; esters, amides or nitrites of (meth)acrylic acid; maleate esters; fumerate esters; vinyl esters; conjugated dienes; itaconic acid; styrenic compounds; and vinylidene halides;
(b) 10-80, preferably 20-50, weight percent of the primary toughener;
(c) 0-15, preferably 1-10, weight percent of the auxiliary toughener;
(d) 0-20, preferably 2-10, weight percent of a phosphorus adhesion promotor compound having one or more olefinic groups,
(e) 0.05-10, preferably 0.1-6, weight percent of at least one reducing agent which is interactive with an oxidizing agent to produce free radicals which are capable of initiating and propagating free radical polymerization reactions; and in the B-Side or second package a bonding activator containing an oxidizing agent of a room temperature-active redox couple catalyst system, the oxidizing agent being reactive at room temperature with agent, and 3-6% wt. on total weight of A and B sides, of an epoxy resin.
In the general embodiment containing a specified amount of epoxy resin, the A-side of the two part reactive acrylic structural adhesive contains 10-90% by weight of at least one free radical-polymerizable monomer in a major amount (the primary monomer). Representative monomers include esters of (meth)acrylic acid such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate, butyl acrylate, cyclohexyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, ethyl acrylate, diethylene glycol dimethacrylate, dicyclopentadienyloxyethyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, glycidyl methacrylate and tetrahydrofurfuryl methacrylate (THFMA). The preferred monomer contributes rigidity in the cured polymer and are selected from methacrylic esters exhibiting a homopolymer Tg of at least 80xc2x0 C., preferably 105xc2x0 C. The major monomer may be combined with an ethylenic unsaturated carboxylic monomer such as methacrylic acid, acrylic acid, substituted (meth)acrylic acids such as itaconic acid. Further optional comonomers includable herein are acrylonitrile, methacrylonitrile, acrylamide and methacrylamide; styrene; substituted styrenes such as vinyl styrene, chlorostyrene, methyl styrene and n-butyl styrene; vinyl acetate; vinylidene chloride; and butadienes such as 2,3-dichloro-1,3-butadiene and 2-chloro-1,3-butadiene. Other useful monomers include maleate esters; fumarate esters; and styrenic compounds such as styrene, chlorostyrene, methylstyrene, butylstyrene and vinyl styrene. In one embodiment, a mixture of the monomers tetrahydrofurfuryl methacrylate, methacrylic acid and methyl methacrylate is useful. It is preferred to include a reactive diluent with the primary monomer. In one embodiment the reactive diluent is (meth)acryloyl substituted dibasic acid, such as hydroxyethyl methacryloyl phthalate (HEMA-phthalate).
Comonomers optionally includable with the primary monomer include OH-functional monoethylenic unsaturated monomers like 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl(meth) acrylate, 1,6-hexanediol mono(meth) acrylate, neopentyl glycol inono(meth)acrylate. Preferedly from 2-10 wt % (on wt. of A-side) of a multifunctional crosslinking comonomer is included, such as trimethylohpropane di(meth) acrylate, trimethylolethane di(meth) acrylate, pentaerythritol tri(meth) acrylate, dipentaerythritol penta(meth)acrylate, and epoxy-diacrylates, such as ethoxylated Bisphenol A dimethacrylate.
In the embodiments of the 2-part adhesive exhibiting improved T-peel strength, per se, epoxy resin is optional. The preferred primary monomer contained in the A-side and is distinguished by the moiety in the ester portion, and which exhibits a homopolymer Tg of equal or above 105xc2x0 C. The amount of monomer present is about 10 to about 90 percent by weight of the A-side, and is a least one methacrylate selected from the groups 1) and 2) where group 1) is C3-C10 alkyl monosubstituted cyclohexyl-, or C1-C6 alkyl disubstituted-cyclohexyl-, or C1-C4 alkyl tri-substituted-cyclohexyl-, or C1-C4 alkyl tetra-substituted cyclohexyl methacrylate, and group 2) includes linear or branched C4-C10 alkyl methacrylates. Some specific examples of group 1) and 2) include 3,3,5-trimethylcyclohexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, 3,3,5,5-tetramethylcyclohexyl methacrylate, 3,4,5-trimethycyclohexyl methacrylate, bornyl (C10 H17) methacrylate, isobornyl methacrylate, and (isopropyl methyl) methacrylate. The substituents on the cycloaliphatic group, based on the starting alcohol transesterified with the xcex1,xcex2-unsaturated acid are preferredly in either the 3, 4, and/or 5 ring position. Specific examples or the preferred T-peel improving monomers include 3,3,5-trimethylcyclohexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, 3,3,5,5-tetramethylcyclohexyl methacrylate, 3,4,5-trimethylcyclohexyl methacrylate, bornyl (C10 H17) methacrylate, isobornyl methacrylate, and (isopropyl methyl) methacrylate.
The acrylic adhesive systems of the invention can optionally contain up to about 50, preferably not more than about 25 percent by weight based on total weight of the A-side package of at least one polymerizable olefinic non-acrylic monomer; up to about 60 preferably not more than about 30 percent by weight based on total weight of the A-side package of a polymeric material having an intrinsic viscosity from about 0.1 to about 1.3, such polymeric material being obtained from the polymerization of a styrene monomer, acrylic monomer, substituted acrylic monomer, olefinic non-acrylic monomer or mixtures thereof; up to about 5 percent by weight of an unsaturated dicarboxylic acid ester; up to about 20 percent by weight of an unsaturated carboxylic acid having one or more, preferably one, carboxylic acid group; and up to about 1 percent by weight of a waxy substance selected from the group consisting of paraffin wax, beeswax, ceresin wax and spermaceti wax.
Any suitable toughener can be utilized in the structural adhesives according to the inventions. The toughener examples include various solid and liquid elastomeric polymeric materials, and in particular liquid olefinic-terminated elastomers as described in U.S. Pat. Nos. 4,223,115; 4,452,944; 4,769,419; 5,641,834 and 5,710,235; and olefinic urethane reaction products of an isocanate-functional prepolymer and a hydroxy functional monomer, as described in U.S. Pat. Nos. 4,223,115; 4,452,944; 4,467,071 and 4,769,419, the entire disclosure of each which is hereby incorporated by reference. A-B-A triblock block copolymers are useful tougleners. In one example the A block is polystyrene, alpha-methyl styrene, t-butyl styrene, or other ring alkylated styrenes as well as mixtures of some or all of the above and the B block is an elastomeric segment having a Tg of 0xc2x0 C. or less, such as that derived from a conjugated diene, isobutylene or other olefin, like ethylene-propylene monomer. Commercially available block copolymer tougheners include EUROPRENE(copyright) which are available from Enichem Elastomers Americas, Inc. A preferred toughener is based on a terblock polymer of styrene-[isoprene]-styrene, 25-[550]-25, parts by weight. Other high molecular weight tougheners include, for example, block copolymers and random copolymers including but not limited to polyethylene, polypropylene, styrene-butadiene, polychloroprene, EPDM, chlorinated rubber, butyl rubber, styrene/butadiene/acrylonitrile rubber and chlorosulfonated polyethylene.
Other tougheners include the liquid olefinic-terminated elastomers, wherein the elastomeric moiety is based on homopolymers of butadiene, copolymers of butadiene and at least one monomer copolymerizable therewith, for example, styrene, acrylonitrile, methacrylonitrile (e.g. poly(butadiene-(meth)acrylonitrile or poly(butadiene-(meth)acrylonitrile-styrene) and mixtures thereof; as well as modified elastomeric polymeric materials, such as butadiene homopolymers and copolymers modified by copolymerization therewith of trace amounts of up to about 5 percent by weight of the elastomeric material of at least one functional monomer (such as acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, styrene, and methyl methacrylate to give, for example, methacrylate-terminated polybutadiene homopolyrniers and/or copolymers.
Inclusive as tougheners are the olefinic-terminated polyalkadienes having carboxy ester linking groups and at least one nascent secondary hydroxyl group, such as disclosed in U.S. Pat. No. 5,587,433, incorporated therein by reference. The secondary OH group may be optionally caped using a diiuocyanate as is disclosed in commonly owned U.S. Pat. No. 5,641,834, incorporated herein by reference.
Specific examples of adducted hydroxy-terminated polybutadiene include the reaction of anhydride modified OH-terminal PBD with an epoxy, such as glycidyl substituents.
A preferred toughener system utilizes a combination of two polymers having differing molecular weights as is taught in U.S. Pat. No. 6,225,408. A specific example taught therein is combination of a major amount of a primary toughener with a weight average molecular weight (Mw) less than about 18,000 together with a minor amount of an auxiliary toughener with a Mw greater than about 18,000. A specific example is a 60:40 mixture of glycidyl methacrylate terminated CTBN rubber, and a terblock copolymer of styrene-[isoprene]-styrene, at 25-[75]-25 parts by weight
Adhesion promoters useful herein are the known phosphorus-containing compounds with mono-esters of phosphinic, mono- and diesters of phosphonic and phosphoric acids having one unit of vinyl or allylic unsaturation present. Vinylic unsaturation is preferred. Representative of the phoshorus-containing adhesion promoters are, without limitation, phosphoric acid; 2-methacryloyloxyethyl phosphate; bis-(2-methacryloxyloxyethyl)phosphate; 2-acryloyloxyethyl phosphate; bis-(2-acryloyloxyethyl)phosphate; methyl-(2-methacryloyloxyethyl)phosphate; ethyl methacryloyloxyethyl phosphate; methyl acryloyloxyethyl phosphate; ethyl acryloyloxyethyl phosphate; propyl acryloylbxyethyl phosphate, isobutyl acryloyloxyethyl phosphate, ethylhexyl acryloyloxyethyl phosphate, halopropyl acryloyloxyethyl phosphate, haloisobutyl acryloyloxyethyl phosphate or haloethylhexyl acryloyloxyethyl phosphate; vinyl phosphonic acid; cyclohexene-3-phosphonic acid; (xcex1-hydroxybutene-2 phosphonic acid; 1-hydroxy-1-phenylmethane- 1,1-diphosphonic acid; 1-hydroxy- 1-methyl-1-disphosphonic acid: 1-amino-1phenyl-1,1-diphosphonic acid; 3-amino-3-hydroxypropane-1,1-disphosphonic acid; amino-tris(methylenephosphonic acid); gamma-amino-propylphosphonic acid; gamma-glycidoxypropylphosphonic acid; phosphoric acid-mono-2-aminoethyl ester; allyl phosphonic acid; allyl phosphinic acid; xcex2-methacryloyloxyethyl phosphinic acid; diallylphosphinic acid; xcex2-methacryloyloxyethyl)phosphinic acid and allyl methacryloyloxyethyl phosphinic acid. A preferred adhesion promoter: is 2-hydroxyethylmethacrylate phosphate.
The above reactive phosphorus-containing compounds are illustrated by the formula:
wherein R20 is selected from, the group consisting of hydrogen, an alkyl group having from one to 8, preferably one to 4, carbon atoms, and CH2CHxe2x80x94; R21 is selected from the group consisting of hydrogen, an alkyl group having from one to 8, preferably one to 4 carbon atoms; A is selected from the group consisting of xe2x80x94R22Oxe2x80x94 and R23O)n, wherein R22 is an aliphatic or cycloaliphatic alkylene group containing from one to 9, preferably 2 to 6, carbon atoms; R23 is an alkylene group having from one to 7, preferably 2 to 4, carbon atoms; n is an integer from 2 to 10, and m is one or 2, preferably one.
The initiator system includes at least one oxidizing agent in the B-side and at least one reducing agent in the A-side. This system is co-reactive at ambient conditions on mixture of Parts A and B to initiate addition polymerization reactions and cure the adhesive. Substantially any of the known oxidizing and reducing agents which are co-reactive at ambient conditions in air, can be employed.
Reducing agent is in the A-side at a typical suggested level of from 0.01 to 10, preferably 0.5 to 5, percent by weight, based on the total weight of A-side components. Representative reducing agents include, without limitation, sulfinic acids; azo compounds such as azoisobutyric acid dinitrile; alpha-aminosulfones such as bis(tolysulfonmethyl)-benzyl amine; tertiary amines such as diisopropanol-p-toluidine (DIIPT), diethanol-p-toluidine, dimethyl aniline, p-halogenated aniline derivatives and dimethyl-p-toluidine; and aminealdehyde condensation products, for example, the condensation products of aliphatic aldehydes such as butyraldelyde with primary amines such as aniline or butylamine.
The reducing agents are preferably tertiary amines. Representative preferred reducing agents are illustrated by the structure
wherein Z is methylene; Y is selected from the group consisting of hydrogen, hydroxy, amino, halogen, alkyl having 1 to 8, preferably 1 to 4, carbon atoms, and alkoxy having 1 to 8, preferably 1 to 4, carbon atoms; a is 0 or 1; and b is 1 or 2. Examples include N,N-dimethyl aniline and N,N-dimethylaminomethylphenol.
According to a preferred embodiment of the invention, the A-side contains a parahalogenated tertiary amine reducing agent having the formula:
wherein each of R1 and R2, which may be the same or different, is independently selected from the group consisting of linear or branched, saturated or unsaturated, C1-C10 alkyl and linear or branched, saturated or unsaturated, C1-C10 hydroxyalkyl (i.e., alkyl substituted by xe2x80x94OH); each of R3 and R4 is independently selected from the group consisting of hydrogen and linear or branched, saturated or unsaturated C1-C10 alkyl; and X is halogen, preferably chlorine.
Representative bonding activators are oxidizing agents including, without limitation, organic peroxides, such as benzoyl peroxide and other diacyl peroxides, hydroperoxides such as cumene hydroperoxide, pelresters such as xcex2-butylperoxybenzoate; ketone hydroperoxides such as methyl ethyl ketone hydroperoxide, organic salts of transition metals such as cobalt naphthenate, and compounds containing a labile chlorine such as sulfonyl chloride. Preferably, the oxidizing agent will be present in an amount in the range from about 0.5 to about 50 percent by weight of bonding accelerator, with the amount of reducing agent being in the range from about 0.05 to about 10 preferably about 0.1 to about 6, percent by weight of polymerizable adhesive composition. DIIPT is a preferred reducing agent. The most preferred oxidizing agent is benzoyl peroxide.
The bonding activator is present at from about 0.5 to about 50 percent by weight based on total weight of B-side and from about 30 to about 99.5 percent by weight, based on total weight of B-side can include a carrier vehicle.
The carrier vehicles which are suitable for use in the bonding activators can be a simple inert solvent or diluent such as methylene chloride, or butyl benzyl phthalate, including mixtures of such solvents or diluents. The carrier vehicle should contain no more than 5% by weight of any moiety which is reactive with the oxidizing agent at room temperature. The carrier vehicle can be a more complex mixture including at least one film-forming binder in addition to inert solvent or diluent. The carrier vehicle can contain, in addition to solvent or solvent and film-forming binder, additives such as external plasticizers, flexibilizers, suspenders and, stabilizers, providing that any such additives do not unacceptably adversely affect the stability of the activator composition.
The epoxy compound of the present invention can be any material that contains an epoxy (oxirane) group. Included epoxy resins are epoxy cresol novolacs, epoxy phenol novolacs and blends of either of these with bisphenol A epoxy resins. Monomeric epoxy compounds and epoxides of the polymeric type and can be aliphatic, cycloaliphatic, aromatic or heterocyclic. The xe2x80x9caveragexe2x80x9d number of epoxy groups per molecule is determined by dividing the total number of epoxy groups in the epoxy-containing material by the total number of epoxy molecules present. Useful epoxy materials generally contain on the average at least 1.5 polymerizable epoxy groups per molecule. Preferably two or more epoxy groups per molecule are present. The polymeric epoxides include linear polymers having terminal epoxy groups (e.g., a diglycidyl ether of a polyoxyalkylene glycol), polymers having skeletal oxirane units (e.g., polybutadiene polyepoxide), and polymers having pendent epoxy groups (e.g., a glycidyl methacrylate polymer or copolymer). The epoxides may be pure compounds but are generally mixtures containing one, two, or more epoxy groups per molecule.
The epoxy-containing materials may vary from low molecular weight monomeric materials to high molecular weight polymers and may vary greatly in the nature of their backbone and substituents groups. For example, the backbone may be of any type and substituents groups thereon being free of an active hydrogen atom. Illustrative of permissible substituents groups include halogens, ester groups, ethers, sulfonate groups, siloxane groups, nitro groups, phosphate groups, etc. The molecular weight of the epoxy-containing materials may vary from about 50 to 100,000 or more. Mixtures of various epoxy-containing materials can also be used in the compositions of this invention.
The epoxy compounds of the present invention can be cycloaliphatic epoxides. Examples of cycloaliphatic epoxides include diepoxides of cycloaliphatic esters of dicarboxylic acids such as bis(3,4-epoxycyclohexylmethyl)oxalate, bis(3,4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, bis(3,4-epoxycyclohexylmethyl)pimelate, and the like. Other suitable diepoxides of cycloaliphatic esters of dicarboxylic acids are described in, for example, U.S. Pat. No. 2,750,395, which is incorporated herein by reference.
Other cycloaliphatic epoxides include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxyliates such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate; 3,4-epoxy-1-methylcyclohexylmethyl-3,4-epoxy-1-methylcyclohexane carboxylate; 6-methyl-3,4-epoxycyclohexylmethyl-6-methyl-3,4-epoxycyclohexane carboxylate; 3,4-epoxy-2-niethylcyclohexylmethyl-3,4-epoxy-2-methylcyclohexane carboxylate; 3,4-epoxy-3-niethylcyclohexylmethyl-3,4-epoxy-3-methylcyclohexane carboxylate; 3,4-epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexane carboxylate and the like. Other suitable 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylates are described in, for example, U.S. Pat. No. 2,890,194, which is incorporated herein by reference.
Epoxy resins based on bisphenol A, either solids, per se, and capable of dissolution in a carrier, or liquids per se, are preferred as these are relatively inexpensive. There are a myriad of available epoxy materials, collectively referred to as epoxy resins whether resinous or simple compounds. In particular, simple epoxy compounds which are readily available include octadecylene oxide, glycidylmethacrylate, diglycidyl ether of bisphenol A (e.g., those available under the trade designations EPON from Shell Chemical Co., DER, from Dow Chemical Co.), vinylcyclohexene dioxide (e.g., ERL-4206 from Union Carbide Corp.), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate (e.g., ERL-4221 from Union Carbide Corp.), 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexene carboxylate (e.g., ERL-4201 from Union Carbide Corp.), bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate (e.g. ERL-4289 from Union Carbide Corp.), bis(2,3-epoxycyclopentyl) ether (e.g., ERL-0400 from Union Carbide Corp.), aliphatic epoxy modified with polypropylene glycol (e.g., ERL-4050 and ERL-4052 from Union Carbide Corp.), dipentene dioxide (e.g., ERL-4269 from Union Carbide Corp.), epoxidized polybutadiene (e.g., OXIRON 2001 from FMC Corp.), silicone resin containing epoxy functionality, flame retardant epoxy resins (e.g., DER-580, a brominated bisphenol type epoxy resin available from Dow Chemical Co.), 1,4-butanediol diglycidyl ether of phenolformaldehyde novolak (e.g., DEN-431 and DEN-438 from Dow Chemical Co.), and resorcinol diglycidyl ether.
Still other epoxy-containing materials are copolymers of epoxy (meth)acrylic acid esters, such as glycidylacryiate and glycidylmethacrylate with one or more copolymerizable vinyl compounds. Examples of such copolymers are 1:1 styrene-glycidylmethacrylate, 1:1 methylmethacrylateglycidyl acrylate and a 62.5:24:13.5 methylmethacrylate-ethyl acrylateglycidylmethacrylate.
The A-side can also include up to about 60, preferably not more than about 30, percent by weight based on the total weight of the composition of a polymeric component having an intrinsic viscosity of 0.1 to 1.3. These can be obtained by the polymerization of at least one acrylic, styrene, substituted acrylic and non-acrylic olefinic monomers. Exemplary polymeric materials include poly(methyl methacrylate/n-butylacrylate/ethyl acrylate) (90/5/5); poly (n-butyl methacrylate/isobutyl methacrylate) (50/50); poly(n-butyl methacrylate), poly(ethyl methacrylate), and poly(tetrahydrofurfurylmethacrylate).
The adhesives can optionally contain 0.005 up to 5 weight percent, preferably 0.05 up to 2 weight percent, based on the total weight of the two parts of a cure rate moderator which is a vinyl aromatic compound, as disclosed in U.S. Pat. No. 5,869,160, incorporated herein by reference. The vinyl aromatic rate moderator excludes a polymer or an oligomer and comprises a vinyl functionals group bonded to at least one aryl ring. The compound can be substituted in the sense that another functional group can be bonded to the vinyl-functional group or the aryl ring. Preferably, the vinyl aromatic compound has a structure represented by the following formula:
(CX2=CX)axe2x80x94Arxe2x80x94(Z)b
wherein each X is the same or different and is hydrogen, alkyl, aryl or halogen; Ar is at least one aryl ring; and Z is a substituents on any position of the aryl ring(s) and is alkyl, alkoxy, aryl, aryloxy, halogen, haloalkyl, haloaryl, alkylaryl, arylalkyl, alkanoyl, and oxyalkanoyl; a is 1 or 2; and b is 0 to 9, preferably 1 to 9. X preferably is hydrogen or methyl. Ar preferably is only one aryl ring, but may be up to three rings. Ar also can be an aryl ring that include a heteroatom such as nitrogen, oxygen or sulfur. Z preferably is an alkyl group such as methyl, ethyl or tert-butyl, a halogen such as chlorine or bromine, a haloalkyl such as chloromethyl, or an oxyalkanoyl such as acetoxy. A substituted vinyl aromatic compound (i.e., X is a group other than hydrogen and/or b is at least 1) is preferred. If the substituents groups X or Z contain carbon, the number of carbon atoms can be limited to a reasonable amount (such as 10) to prevent steric hindranrce, reactivity or synthesis problems.
Illustrative vinyl aromatic compounds include (xcex1-methylstyrene, 3-methylstyrene, 4-methylstyrene (i.e., vinyl toluene), 4-tert-butylstyrene, 4-methoxystyrene, 9-vinylanthracene, 2-bromostyrene, 3-bromostyrene, 4-bromostyrene, 4-acetoxystyrene, 4-benzyloxy-3-methoxystyrene, 4-chloromlethylstyrene, 4-vinylpyridine, 1,1-diphenylethylene, styrene, xcex1-methyl-p-methyl styrene, 2-vinyl pyridine and divinyl benzene. Especially preferred are xcex1-methylstyrene and 4-methylstyrene.
Other optional additives which are typically considered in fully formulated adhesives include antioxidants, inhibitors, anti-sag additives, thixotropes, processing aids, waxes, UV stabilizers, arc suppressants, and drip suppressants. Examples of typical additives are fumed silica, alumina, hindered phenols, substituted hydroquinone, silane-treated talc, mica, feldspar, and wollastonite.
Although the adhesive of the present invention may take many forms, the most preferred adhesive systems are provided as multipack or two-part adhesive systems where one package or part contains the polymerizable or reactive components and the reducing agent and a second package or part contains the oxidizing agent. The two parts are mixed together at the time of use in order to initiate the reactive cure. The preferred means for dispensing the adhesive are two-chambered cartridges equipped with static mixers in the nozzle, and for larger scale application, meter mix dispensing equipment. After mixing the individual packages, one or both surfaces to be joined are coated with the mixed adhesive system and the surfaces are placed in contact with each other.
The adhesive systems of the invention may be used to bond metal surfaces, such as steel, aluminum and copper, to a variety of substrates, including metal, plastics, and other polymers, reinforced plastics, fibers, glass, ceramics, wood and the like. The adhesives are particularly useful in hem flange bonding of auto body panels. It is a feature of the present invention that the herein-described adhesive compositions can be employed to bond metal substrates such as steel, aluminum and copper with little, if any, pretreatment of the metal surface prior to application of the adhesive. Thus, bonding can be effected even to oily metal surfaces which are otherwise clean without an extensive pretreatment as is usually required with the vast majority of currently available primers and adhesives. Additionally, the adhesive systems of this invention provide effective bonding at room temperature, thus heat is not required either for applying the adhesive systems to the substrates or for curing.
Although the adhesives of the present invention are preferred for bonding metal surfaces, the present adhesive compositions may be applied as an adhesive, primer or coating to any surface or substrate capable of receiving the adhesive. The metals which are preferred for bonding with the present adhesives include zinc, copper, cadmium, iron, tin, aluminum, silver, chromium, alloys of such metals, and metallic coatings or platings of such metals such as galvanized steel including hot dipped, electrogalvanized steel and galvanealed steel.
The adhesive coatings may be brushed, rolled, sprayed, dotted, knifed, cartridge-applied, especially from a dual cartridge; or otherwise applied to one substrate, but preferably to both substrates to desired thickness preferably not to exceed 60 mils. The substrates may be clamped for firmness during cure in those installations where relative movement of the two substrates might be expected. For example, to adhere metal surfaces, an adherent quantity of the adhesive composition is applied to one surface, preferably to both surfaces, and the surfaces are confronted with the adhesive composition therebetween. The adhesive should have a thickness less than 60 mils for optimum results. The smoothness of the surfaces and their clearance (e.g., in the case of nuts and bolts) will determine the required film thickness for optimum bonding. The two metal surfaces and the interposed adhesive composition are maintained in engagement until the said adhesive composition has cured sufficiently to bond the said surfaces. Incorporation of glass beads to control bondline thickness is preferred especially in hemming operations, as is taught in U.S. Pat. Nos. 5,487,803 and 5,470,416.

Two-part adhesive: part A-monomer, toughener(s), optional adhesion promotor and reducing agent; part B-epoxy resin

Abstract: in a first package

Abstract: C3-C10 alkyl monosubstituted-, C1-C6 alkyl disubstituted-, C1-C4 alkyl tri-substituted, and F1-C4 alkyl tetra-substituted cyclohexyl methacrylate. The ring substituents are prefereably in the 3, 4, and/or 5 ring position, and linear or branched C4-C10 branched alkyl methacrylates;

Abstract: from about 10 to about 80 percent by weight of a toughener, and an adhesion promotor; and


The invention relates to a process for uniformly dispersing a transition metal metallocene complex on a carrier comprising

The invention relates to the production of bimetallic catalyst systems for ethylene polymerization reactions. The catalysts contain two types of transition metals and produce polyethylene resins with broad and/or bimodal molecular weight distribution (MWD) in a single reactor. In a preferred embodiment, the invention relates to the production of titanium/zirconium-based bimetallic catalyst systems that produce broad and/or bimodal MWD polyethylene resins in a single reactor. In the most preferred embodiment, the low molecular weight (LMW) component in the resin is produced by the Zr active centers, while the high molecular weight (HMW) component is produced by the Ti active centers. The relative productivity of the two active centers determines the ratio of the HMW and the LMW components in the final resin.
This invention particularly relates to a new procedure for preparing bimetallic catalysts. This procedure results in bimetallic catalysts with a more uniform inter-particle distribution of the metals. With increasing uniformity in inter-particle distribution of the metals, the gel content in polyethylene resins decreases. The bimetallic catalysts are used in (co)polymerization reactions to produce high molecular weight polyethylene product. Gels are attributable to high molecular weight components in the resins which are substantially greater in molecular weight than the surrounding matrix resin. The presence of gels in a resin results in poor appearance when the resin is fabricated into film. The presence of gels also interferes with the uniform printing on films. Films possessing very high gel levels also suffer in some film performance characteristics, such as tensile strength.
This invention relates to supported titanium-zirconium bimetallic catalysts with an improved inter-particle metal distribution of the Zr active centers and facilitates the scale-up of the catalysts.
This invention also includes a new procedure for preparing bimetallic catalysts. This procedure results in bimetallic catalysts with a more uniform inter-particle distribution of transition metal(s). The process comprises
(1) providing silica which is porous and has a particle size of 1 to 250 microns, having pores which have an average diameter of 50 to 500 Angstroms and having a pore volume of 0.5 to 5.0 cc/g;
(2) slurrying the silica in an aliphatic solvent having a boiling point lower than 110xc2x0 C.;
(3) providing a volume of a solution comprising a metallocene complex, alumoxane of formulas Rxe2x80x94(Al(R)xe2x80x94Oxe2x80x94)xxe2x80x94AlR2 for oligomeric linear alumoxanes and (xe2x80x94Al(R)xe2x80x94Oxe2x80x94)y for cyclic alumoxanes wherein x is 1-40, y is 3-40, and R is a C1-C8 alkyl group in an aromatic solvent wherein the volume of the solution is lower than that required to form a slurry of said silica;
(4) contacting the silica with said volume of said solution (3) and allowing the solution to impregnate the pores of silica, and to disperse the metallocene complex in and on the carrier;
(5) evaporating solvents from the impregnated silica slurry, to recover dry free-flowing catalyst particles.
Catalyst Composition
The invention relates to a supported olefin (co)polymerization catalyst composition which is synthesized to uniformly disperse at least one transition metal component on the support. In preferred embodiments, the catalysts contain at least two transition metals, at least one in the form of a metallocene complex. A second transition metal on the support may be in the form of a non-metallocene component or a second metallocene complex, different from the first mentioned metallocene complex, but is preferably a non-metallocene compound. The catalyst compositions of the invention comprise a cocatalyst comprising an alkyl aluminum compound, such as a trialkylaluminum, free of alumoxane and free of oxygen-containing oligomers and polymers of the alkyl aluminum compounds, and a catalyst precursor comprising a carrier, an alumoxane and at least one metallocene; in one embodiment the catalysts further include a second transition metal source.
In accordance with the invention, these catalysts are made by a process for forming a carrier material impregnated with alumoxane and derivatives thereof comprising the steps
(1) providing silica which is porous and has a particle size of 1 to 250 microns, having pores which have an average diameter of 50 to 500 Angstroms and having a pore volume of 0.5 to 5.0 cc/g;
(2) slurrying the silica in an aliphatic solvent having a boiling point less than 110xc2x0 C., preferably by stirring at a temperature in the range of 20 to 25xc2x0 C.;
(3) providing a volume of a solution comprising a metallocene, alumoxane of formulas Rxe2x80x94(Al(R)xe2x80x94Oxe2x80x94)xxe2x80x94AlR2 for oligomeric linear alumoxanes and (xe2x80x94Al(R)xe2x80x94Oxe2x80x94)y for cyclic alumoxanes wherein x is 1-40, y is 3-40, and R is a C1-C8 alkyl group in an aromatic solvent, wherein the concentration of alumoxane, expressed as Al weight percent is 5 to 20; and wherein the volume of the solution is sufficient to impregnate the pores of silica without forming a slurry of the silica in the solvent;
(4) contacting the silica with said volume of said solution (3);
(5) evaporating solvents from the impregnated silica to recover dry free-flowing catalyst particles.
The metallocene complex becomes more uniformly distributed throughout the support as a result of steps (2) and (4). When two transition metal sources exhibiting different hydrogen responses in ethylene polymerization reactions are supported on the carrier subjected to the process of the invention, the result of the catalyst preparation process is an olefin polymerization catalyst composition which produces less gels in the polyethylene film produced from the polyethylene prepared with the catalyst composition. In the process of the invention, step (2) may be undertaken prior to or after (4).
The carrier material is a solid, particulate, porous, preferably inorganic material, such as an oxide of silicon and/or of aluminum. The carrier material is used in the form of a dry powder having an average particle size of from about 1 micron to about 500 microns, preferably from about 10 microns to about 250 microns. The surface area of the carrier is at least about 3 square meters per gram (m2/g), and preferably at least about 50 m2/g up to about 350 m2/g. The carrier material should be free of absorbed water. Drying of the carrier material can be effected by heating at about 100xc2x0 C. to about 1000xc2x0 C., preferably at about 600xc2x0 C. When the carrier is silica, it is heated to at least 200xc2x0 C., preferably about 200xc2x0 C. to about 850xc2x0 C. and most preferably at about 600xc2x0 C. The carrier material must have at least some active hydroxyl (OH) groups to produce the catalyst composition of this invention.
In the most preferred embodiment, the carrier is silica which, prior to the use thereof in the first catalyst synthesis step, has been dehydrated by fluidizing it with nitrogen and heating at about 600xc2x0 C. for about 4-16 hours to achieve a surface hydroxyl group concentration of about 0.7 mmol/g. The silica of the most preferred embodiment is a high surface area, amorphous silica (surface area=300 m2/g; pore volume of about 1.65 cm3/g), and it is a material marketed under the tradenames of Davison 952 or Davison 955 by the Davison Chemical Division of W. R. Grace and Company. The silica is in the form of spherical particles and obtained by the spray-drying process. As procured, these silicas are not calcined; and this must be dehydrated, as indicated above.
The catalyst synthesis is undertaken under inert conditions in the absence of water and oxygen.
The carrier material having said OH groups is slurried in a non-polar solvent. The slurry of the carrier material is prepared by introducing the carrier into the solvent, preferably while stirring, and heating the mixture to about 25 to about 70xc2x0 C., preferably to about 40 to about 60xc2x0 C. Temperature of the slurry is critical with respect to the activity of the catalyst components added to it. All catalyst precursor synthesis steps should be conducted at temperatures below 90xc2x0 C.
In embodiments of the invention, incorporation of the first transition metal component in the catalyst occurs prior to undertaking steps (3) and (4). In specific embodiments, incorporation of the first transition metal component involves a series of steps. Initially, the carrier is contacted with an organomagnesium compound which has the empirical formula RmMgRxe2x80x2n where R and Rxe2x80x2 are the same or different C2-C12 alkyl groups, preferably C4-C10 alkyl groups, more preferably C4-C8 alkyl groups, and most preferably both R and Rxe2x80x2 are butyl groups, and m and n are each 0, 1 or 2, providing that m+n is equal to the valence of Mg. Optionally, but preferably, the organomagnesium-impregnated carrier is thereafter contacted with an alcohol and lastly with a non-metallocene transition metal source. Most preferably, these steps are undertaken in the order noted and without isolation of a dry product until after the non-metallocene transition metal compound incorporation.
Suitable non-polar solvents for slurrying silica and introduction of the first transition metal component are materials which are liquid at reaction temperatures and in which all of the reactants used herein, i.e., the organomagnesium compound, the alcohol and the transition metal compound, are at least partially soluble. Preferred non-polar solvents are alkanes, such as isopentane, hexane, isohexane, n-heptane, octane, nonane, and decane, although a variety of other materials including cycloalkanes, such as cyclohexane, aromatics, such as benzene, toluene and ethylbenzene, may also be employed. The most preferred non-polar solvent is isopentane. Prior to use, the non-polar solvent should be purified, such as by percolation through silica gel and/or molecular sieves, to remove traces of water, oxygen, polar compounds, and other materials capable of adversely affecting catalyst activity. In certain embodiments of the invention, two aliphatic solvents may be used, one for the incorporation of the non-metallocene transition metal and second aliphatic solvent for use in the incorporation of metallocene with an aromatic solvent. Accordingly, in the embodiment of titanium incorporation into the silica with the aliphatic solvent, that solvent will be referred as the first aliphatic solvent; and when an aliphatic solvent is used in conjunction with metallocene incorporation into the support, the aliphatic solvent will be referred as the second aliphatic solvent.
In the most preferred embodiment of the synthesis of this catalyst it is important to add only such an amount of the organomagnesium compound to the silica slurry that will be deposited, physically or chemically, onto the support since any excess of the organomagnesium compound in the solution may react with the other synthesis chemicals and precipitate outside of the support. The carrier drying temperature affects the number of sites on the carrier available for the organomagnesium compound: the higher the drying temperature the lower the number of sites. Thus, the exact molar ratio of the organomagnesium compound to the hydroxyl groups will vary and must be determined on a case-by-case basis to assure that only so much of the organomagnesium compound is added to the solution as will be deposited onto the support without leaving any excess of the organomagnesium compound in the solution. Thus, the molar ratios given below are intended only as an approximate guideline and the exact amount of the organomagnesium compound in this embodiment must be controlled by the functional limitation discussed above, i.e., it must not be greater than that which can be deposited onto the support. The required amount of the organomagnesium compound can be determined in any conventional manner, e.g., by adding the organomagnesium compound to the slurry of the carrier in the solvent, while stirring the slurry, until the organomagnesium compound is detected in the solvent.
For example, for the silica carrier heated at about 600xc2x0 C., the amount of the organomagnesium compound added to the slurry is such that the molar ratio of Mg to the hydroxyl groups (OH) on the solid carrier is about 0.5:1 to about 4:1, preferably about 0.8:1 to about 3:1, more preferably about 0.9:1 to about 2:1 and most preferably about 1:1. The organomagnesium compound dissolves in the non-polar solvent to form a solution from which the organomagnesium compound is deposited onto the carrier. The amount of the organomagnesium compound based on the amount of silica ranges from 0.2 mmol/g to 2 mmol/g, preferably from 0.4 mmol/g to 1.5 mmol/g, more preferably from 0.6 mmol/g to 1.0 mmol/g, and most preferably from 0.7 mmol/g to 0.9 mmol/g. The RMgRxe2x80x2 provides 0.6 to 1.0 mmol Mg/g silica, or 0.7 to 0.9 mmol Mg/g silica.
It is also possible to add the organomagnesium compound in excess of the amount deposited onto the support and then remove it, e.g., by filtration and washing. However, this alternative is less desirable than the most preferred embodiment described above.
The organomagnesium compound-treated support is contacted with an organic alcohol (ROH) containing RO groups which displace alkyl groups attached to the magnesium atom. The amount of the alcohol is effective to provide a ROH:Mg [mol/mol] ratio which ranges from 0.2 to 1.5, preferably from 0.4 to 1.2, more preferably from 0.6 to 1.1, most preferably from 0.9 to 1.0.
Contact of the silica-supported magnesium compound with the alcohol is also undertaken in the slurry at a temperature ranging from 25xc2x0 C. to 80xc2x0 C., preferably at 40xc2x0 C. to 70xc2x0 C.
The alkyl group in the alcohol can contain 1 to 12 carbon atoms, preferably 1 to 8; in the embodiments below, it is an alkyl group containing 2 to 4 carbon atoms, particularly four carbon atoms (n-butanol). The inclusion of the alcohol addition step in the catalyst synthesis of the invention produces a final catalyst which is much more active, requires much less non-metallocene transition metal compound (e.g., or titanium compound) and is much more active with respect to the the metallocene complex, as opposed to exclusion of the alcohol addition step.
After the addition of the alcohol to the slurry is completed, the slurry is contacted with the first source of transition metal, preferably non-metallocene transition metal compound. The slurry temperature at this stage must be maintained at about 25 to about 70xc2x0 C., preferably to about 40 to about 60xc2x0 C., because temperatures above 80xc2x0 C. can result in deactivation of the non-metallocene transition metal component. Suitable non-metallocene transition metal compounds used herein are compounds of metals of Groups 4A, and 5A, of the Periodic Chart of the Elements, as published by Chemical and Engineering News, 63(5), 27, 1985, providing that such compounds are soluble in the non-polar solvents. Non-limiting examples of such compounds are titanium and vanadium halides, e.g., titanium tetrachloride (TiCl4), vanadium tetrachloride (VCl4), vanadium oxytrichloride (VOCl3), titanium and vanadium alkoxides, wherein the alkoxide moiety has a branched or unbranched alkyl radical of 1 to about 20 carbon atoms, preferably 1 to about 6 carbon atoms. The preferred transition metal compounds are titanium compounds, preferably tetravalent titanium compounds. The most preferred titanium compound is TiCl4. The amount of titanium or vanadium ranges from a Ti/Mg molar ratio of 0.3 to 1.0, preferably from 0.50 to 0.80.
Mixtures of such transition metal compounds may also be used and generally no restrictions are imposed on the transition metal compounds which may be included. Any transition metal compound that may be used alone may also be used in conjunction with other transition metal compounds. After the addition of the first transition metal compound is completed, the solvent is removed by evaporation or filtering to obtain a free-flowing powder of the catalyst intermediate.
Next, incorporation of the metallocene transition metal compound into the catalyst intermediate is undertaken. The metallocene compound is pre-activated with an alkyl alumoxane.
Incorporation of the metallocene complex and its uniform distribution in the support is achieved in a mixed solvent system.
The metallocene compound has the formula CxMAyBz in which C is an unsubstituted or substituted cyclopentadienyl group, M is zirconium or hafnium atom and A and B belong to the group including a halogen atom, hydrogen atom or an alkyl group. In the above formula of the metallocene compound, the preferred transition metal atom M is zirconium. In the above formula of the metallocene compound, the C group is an unsubstituted, a mono- or a polysubstituted cyclopentadienyl group: and x is at least 1. The substituents on the cyclopentadienyl group can be preferably straight-chain C1-C6 alkyl groups. The cyclopentadienyl group can be also a part of a bicyclic or a tricyclic moiety such as indenyl, tetrahydroindenyl, fluorenyl or a partially hydrogenated fluorenyl group, as well as a part of a substituted bicyclic or tricyclic moiety. In the case when x in the above formula of the metallocene compound is equal to 2, the cyclopentadienyl groups can be also bridged by polymethylene or dialkylsilyl groups, such as xe2x80x94CH2xe2x80x94, xe2x80x94CH2xe2x80x94CH2xe2x80x94, xe2x80x94CRxe2x80x2Rxe2x80x3xe2x80x94 and xe2x80x94CRxe2x80x2Rxe2x80x3xe2x80x94CRxe2x80x2Rxe2x80x3xe2x80x94 where Rxe2x80x2 and Rxe2x80x3 are short alkyl groups or hydrogen atoms, xe2x80x94Si(CH3)2xe2x80x94, Si(CH3)2xe2x80x94CH2xe2x80x94CH2xe2x80x94Si(CH3)2xe2x80x94 and similar bridge groups. If the A and B substituents in the above formula of the metallocene compound are halogen atoms, they belong to the group of fluorine, chlorine, bromine or iodine; and y+z is 3 or less, provided that x+y+z equals the valence of M. If the substituents A and B in the above formula of the metallocene compound are alkyl groups, they are preferably straight-chain or branched C1-C8 alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, n-hexyl or n-octyl.
Suitable metallocene compounds include
bis(cyclopentadienyl)metal dihalides,
bis(cyclopentadienyl)metal hydridohalides,
bis(cyclopentadienyl)metal monoalkyl monohalides,
bis(cyclopentadienyl)metal dialkyls and bis(indenyl)metal
dihalides wherein the metal is a zirconium or hafnium atom, halide groups are preferably chlorine and the alkyl groups are C1-C6 alkyls. Illustrative, but non-limiting examples of metallocenes include
Bis(indenyl)zirconium dichloride,
Bis(indenyl)zirconium dibromide,
Bis(indenyl)zirconium bis(p-toluenesulfonate),
Bis(4,5,6,7-tetrahydroindenyl)zirconium dichloride,
Bis(fluorenyl)zirconium dichloride,
Ethylene-bis(indenyl)zirconium dichloride,
Ethylene-bis(indenyl)zirconium dibromide,
Ethylene-bis(indenyl)dimethyl zirconium,
Ethylene-bis(indenyl)diphenyl zirconium,
Ethylene-bis(indenyl)methyl zirconium monochloride,
Ethylene-bis(indenyl)zirconium bis(methanesulfonate),
Ethylene-bis(indenyl)zirconium bis(p-toluenesulfonate),
Ethylene-bis(indenyl)zirconium bis(trifluoromethanesulfonate),
Ethylene-bis(4,5,6,7-tetrahydroindenyl)zirconium dichloride,
Isopropylidene(cyclopentadienyl-fluorenyl)zirconium dichloride,
Isopropylidene(cyclopentadienyl-methylcyclopentadienyl)zirconium dichloride,
Dimethylsilyl-bis(cyclopentadienyl)zirconium dichloride, Dimethylsilyl-bis(methylcyclopentadienyl)zirconium dichloride,
Dimethylsilyl-bis(dimethylcyclopentadienyl)zirconium dichloride,
Dimethylsilyl-bis(trimethylcyclopentadienyl)zirconium dichloride,
Dimethylsilyl-bis(indenyl)zirconium dichloride,
Dimethylsilyl-bis(indenyl)zirconium bis(trifluoromethanesulfonate),
Dimethylsilyl-bis(4,5,6,7-tetrahydroindenyl)zirconium dichloride,
Dimethylsilyl(cyclopentadienyl-fluorenyl)zirconium dichloride,
Diphenylsilyl-bis(indenyl)zirconium dichloride,
Methylphenylsilyl-bis(indenyl)zirconium dichloride,
Bis(cyclopentadienyl)zirconium dichloride,
Bis(cyclopentadienyl)zirconium dibromide,
Bis(cyclopentadienyl)methylzirconium monochloride,
Bis(cyclopentadienyl)ethylzirconium monochloride,
Bis(cyclopentadienyl)cyclohexylzirconium monochloride,
Bis(cyclopentadienyl)phenylzirconium monochloride,
Bis(cyclopentadienyl)benzylzirconium monochloride,
Bis(cyclopentadienyl)zirconium monochloride monohydride,
Bis(cyclopentadienyl)methylzirconium monohydride,
Bis(cyclopentadienyl)dimethylzirconium,
Bis(cyclopentadienyl)diphenylzirconium,
Bis(cyclopentadienyl)dibenzylzirconium,
Bis(cyclopentadienyl)methyoxyzirconium chloride,
Bis(cyclopentadienyl)ethoxyzirconium chloride,
Bis(cyclopentadienyl)zirconium bis(methanesulfonate),
Bis(cyclopentadienyl)zirconium bis(p-toluenesulfonate),
Bis(cyclopentadienyl)zirconium bis(trifluoromethanesulfonate),
Bis(methylcyclopentadienyl)zirconium dichloride,
Bis(dimethylcyclopentadienyl)zirconium dichloride,
Bis(dimethylcyclopentadienyl)ethoxyzirconium chloride,
Bis(dimethylcyclopentadienyl)zirconium bis(trifluoromethanesulfonate),
Bis(ethylcyclopentadienyl)zirconium dichloride,
Bis(methylethylcyclopentadienyl)zirconium dichloride,
Bis(propylcyclopentadienyl)zirconium dichloride,
Bis(methylpropylcyclopentadienyl)zirconium dichloride,
Bis(butylcyclopentadienyl)zirconium dichloride,
Bis(methylbutylcyclopentadienyl)zirconium dichloride,
Bis(methylbutylcyclopentadienyl)zirconium bis(methanesulfonate),
Bis(trimethylcyclopentadienyl)zirconium dichloride,
Bis(tetramethylcyclopentadienyl)zirconium dichloride,
Bis(pentamethylcyclopentadienyl)zirconium dichloride,
Bis(hexylcyclopentadienyl)zirconium dichloride,
Bis(trimethylsilylcyclopentadienyl)zirconium dichloride.
bis(cyclopentadienyl)zirconium dichloride,
bis(cyclopentadienyl)hafnium dichloride,
bis(cyclopentadienyl)zirconium dimethyl,
bis(cyclopentadienyl)hafnium dimethyl,
bis(cyclopentadienyl)zirconium hydridochloride,
bis(cyclopentadienyl)hafnium hydridochloride, bis(n-butylcyclopentadienyl)zirconium dichloride, bis(n-butylcyclopentadienyl)hafnium dichloride, bis(n-butylcyclopentadienyl)zirconium dimethyl, bis(n-butylcyclopentadienyl)hafnium dimethyl, bis(n-butylcyclopentadienyl)zirconium hydridochloride, bis(n-butylcyclopentadienyl)hafnium hydridochloride,
bis(pentamethylcyclopentadienyl)zirconium dichloride,
bis(pentamethylcyclopentadienyl)hafnium dichloride,
bis(n-butylcyclopentadienyl)zirconium dichloride,
cyclopentadienylzirconium trichloride,
bis(indenyl)zirconium dichloride, bis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride, and ethylene-[bis(4,5,6,7-tetrahydro-1-indenyl)] zirconium dichloride.
The metallocene compounds utilized within the embodiment of this art can be used as crystalline solids or solutions in hydrocarbons.
Alumoxanes activate metallocene transition metal compounds. The class of alumoxanes comprises oligomeric linear and/or cyclic alkylalumoxanes represented by the formula: Rxe2x80x94(Al(R)xe2x80x94O)nxe2x80x94AlR2 for oligomeric linear alumoxanes and (xe2x80x94Al(R)xe2x80x94Oxe2x80x94)m for oligomeric cyclic alumoxanes wherein n is 1-40, preferably 10-20, m is 3-40, preferably 3-20 and R is a C1-C8 alkyl group, preferably methyl group. MAO (methylalumoxane)is a mixture of oligomers with a very wide distribution of molecular weights and usually with an average molecular weight of about 1200. MAO is typically kept in solution in toluene. In one embodiment, the amount of Al, provided by alumoxane, is sufficient to provide an Al:transition metal (provided by metallocene) mole ratio ranging from 50 to 500, preferably 75 to 300, more preferably from 85 to 200, and most preferably from 90 to 110.
In accordance with the invention, infusion of the metallocene complex admixed with alumoxane into the carrier is undertaken using the free-flowing powder containing a non-metallocene transition metal compound impregnated into the carrier. The free-flowing powder pre-slurried in a light aliphatic solvent. The pore volume of the carrier is determined and metallocene-alumoxane solution is provided in a volume equal to or less than the total pore volume of the carrier, and recovering a dry catalyst precursor.
The volume of the solution comprising the alumoxane, the metallocene complex and the aromatic solvent therefore can vary. In the preferred embodiment, the volume of the solution comprising the solvent and metallocene-aluminoxane ingredients is lower than that necessary to form a slurry of the carrier material, such as silica, but sufficient to fill the pores of the carrier material. Accordingly and preferably, the maximum volume of the alumoxane-metallocene solution does not exceed the total pore volume of the carrier material. We have found that up to 50% excess of a solvent volume over the total pore volume of the silica can be used without forming a slurry. Accordingly, if the pore volume of the carrier material is 1.65 cm3/l g, then the volume of alumoxane-metallocene solution will be equal to or less than 1.65 cm3/gram of carrier material.
The solvent used to form this solution is one in which each of the metallocene, alumoxane, and activated mixtures thereof are soluble. Preferably, this solvent is an aromatic solvent selected from the group consisting of benzene, xylene or toluene. The most preferred solvent is toluene.
As indicated above, incorporation and uniform dispersion of the metallocene complex in the carrier involves a solvent system consisting of at least two solvents. In accordance with the invention, the first solvent used during the addition of RXgRxe2x80x2, ROH and TiX4 to silica, to form a Ziegler type catalyst intermediate, has a boiling point below 110xc2x0 C. Preferably, the solvent is aliphatic; it may consist of straight or branched chain hydrocarbons with 4 to 7 carbon atoms. Examples include isobutane, pentane, isopentane, hexane, isohexanes, heptane, isoheptanes, methylene dichloride, or chloroform.
The second aliphatic solvent is used to slurry the catalyst intermediate and to receive or to disperse the solution containing the source of metallocene compound in an aromatic solvent. It has a boiling point of less than about 90xc2x0 C. Preferably, its boiling point ranges from xe2x88x9250 to 89xc2x0 C.; more preferably from xe2x88x9225 to 70xc2x0 C., and most preferably from xe2x88x925 to 50xc2x0 C.; in the most preferred embodiments the boiling point of this solvent is in the range of from 10 to 35xc2x0 C.
The second aliphatic solvent is used in the amount required to produce a slurry with a solids content ranging from 10 to 40%, preferably from 15% to 35%. The liquid medium in the final step of catalyst preparation comprises a volume ratio of the light aliphatic solvent to the aromatic solvent which ranges from to 0.5 to 20, preferably from 1.0 to 15, more preferably from 2.0 to 10, most preferably from 2.5 to 8. The slurry is agitated to insure good mixing while the solution of metallocene compound and alumoxane is added to the slurry of the carrier material.
The second aliphatic solvent is evaporated from the slurry to isolate a free-flowing powder containing two sources of transition metal without any filtering. Filtering is avoided to substantially eliminate the loss of catalytic components. The solvent is removed by evaporation at relatively low temperatures, in the range above 40xc2x0 C. and below about 50xc2x0 C. Very short heating time schedules are employed to obviate catalyst degradation.
In a preferred embodiment, the metallocene is added to the solution of the alumoxane prior to impregnating the carrier with the solution. Again, as noted above, the maximum volume of the alumoxane solution also including the metallocene compound should not exceed the total pore volume of the carrier material. The molar ratio of alumoxane, expressed as Al, to metallocene metal expressed as M (e.g. Zr), ranges from 50 to 500, preferably 75 to 300, and most preferably 100 to 200. An added advantage of the present invention is that this Al:Zr ratio can be directly controlled. In a preferred embodiment the alumoxane and metallocene compound are mixed together at a temperature of about 20 to 80xc2x0 C., for 0.1 to 6.0 hours, prior to use in the infusion step. The solvents for the metallocene compound and alumoxane can be hydrocarbons or halogenated aromatic hydrocarbons, preferably it is toluene.
The catalyst precursor component formed from the organomagnesium compound, the non-metallocene transition metal and the activated metallocene complex, must be activated with a cocatalyst, which is an alkylaluminum compound free of oxygen-containing MAO oligomers. Preferably, trimethylaluminum. (TMA) is the cocatalyst. The amount of TMA is sufficient to give an Al:Ti molar ratio of about 10:1 to about 1000:1, preferably about 15:1 to about 300:1, and most preferably about 20:1 to about 100:1. The activated catalyst composition exhibits high activity for long periods of time and shows little deactivation.
The catalyst precursor of this invention comprises a non-metallocene transition metal component, metallocene compound and an alumoxane. It is fed to the fluidized-bed reactor for gas phase polymerization and copolymerization reactions of ethylene in the absence of alumoxane solution.
For the production of ethylene copolymers in the process of the present invention an operating temperature of about 30xc2x0 to 115xc2x0 C. is preferred and a temperature of about 75xc2x0 to 100xc2x0 C. is most preferred. Temperatures of about 75xc2x0 to 90xc2x0 C. are used to prepare products having a density of about 0.91 to 0.92, temperatures of about 80xc2x0 to 100xc2x0 C. are used to prepare products having a density of about 0.92 to 0.94, and temperatures of about 90xc2x0 to 115xc2x0 C. are used to prepare products having a density of about 0.94 to 0.96.
The fluidized-bed reactor is operated at pressures of up to about 1000 psi, and is preferably operated at a pressure of from about 150 to 350 psi, with operation at the higher pressures in such ranges favoring heat transfer since an increase in pressure increases the unit volume heat capacity of the gas.
The partially or completely activated catalyst is injected into the bed at a point above the distribution plate of a fluidized bed reactor at a rate equal to its consumption. Since the catalysts used in the practice of this invention are highly active, injection of the fully activated catalyst into the area below the distribution plate may cause polymerization to begin there and eventually cause plugging of the distribution plate. Injection into the polymer particle bed, instead, aids in distributing the catalyst throughout the bed and precludes the formation of localized areas of high catalyst concentration. Under a given set of operating conditions, the fluidized-bed is maintained at essentially a constant height by withdrawing a portion of the bed as product at a rate equal to the rate of formation of the particulate polymer product.
The production rate of polymer in the bed is controlled by the rate of catalyst injection. Since any change in the rate of catalyst injection changes the rate of generation of the heat of reaction, the temperature of the recycle gas is adjusted to accommodate the change in rate of heat generation. Complete instrumentation of both the fluidized bed and the recycle gas cooling system is necessary to detect any temperature changes in the bed so as to enable the operator to make a suitable adjustment in the temperature of the recycle gas.
Since the rate of heat generation is directly related to the product formation, a measurement of the temperature rise of the gas across the reactor (the difference between the inlet gas temperature and the exit gas temperature) is determinative of the rate of particulate polymer formation at a constant gas velocity.

Bimetallic catalyst for ethylene polymerization reactions with uniform component distribution

Abstract: (2) slurrying the silica in an aliphatic solvent having a boiling point less than 110xc2x0 C.;

Abstract: (3) providing a volume of a solution comprising metallocene and alumoxane wherein the volume of solution is less than that required to form a slurry of the silica, wherein the concentration of alumoxane, expressed as Al weight percent, is 5 to 20; (4) contacting the silica slurry (2) with said volume of said solution (3) and allowing the solution to impregnate the pores of silica and, to disperse the metallocene in and on the carrier; (5) evaporating the solvents from the contacted and impregnated silica to recover dry free-flowing catalyst particles.


A method for valuing a business based on the business generating an acceptable return to an owner during a defined investment period, the method including the steps of assessing the business background for the business to be valued, establishing value optimization factors that determine business value in the light of the business background and the relevant industry of the business to be valued, establishing a business capitalization rate (BCR) appropriate for the business and industry of the business to be valued, calculating a weighted average notional earning before interest and tax (WANEBIT) based on historical financial records of the business to be valued, and calculating the net business value using the WANEBIT and the BCF.

Methods for valuing a business are known. One prior art patent application directed towards such a method is U.S. Pat. No. 6,393,406 to Eder. That document provides an excellent summation of the state of the art as known and a portion of the Background Art section of that patent is reproduced verbatim as follows:
"The valuation of a business is complex and time-consuming undertaking. Business valuations determine the price that a hypothetical buyer would pay for a business under a given set of circumstances. The volume of business valuations being performed each year is increasing significantly. A leading cause of this growth in volume is the increasing use of mergers and acquisitions as vehicles for corporate growth. Business valuations are frequently used in setting the price for a business that is being bought or sold. Another reason for the growth in the volume of business valuations has been their increasing use in areas other than supporting merger and acquisition transactions. For example, business valuations are now being used by financial institutions to determine the amount of credit that should be extended to a company, by courts in determining litigation settlement amounts and by investors in evaluating the performance of company management.
In most cases, a business valuation is completed by an appraiser or a Certified Public Accountant (hereinafter, appraiser) using a combination of judgment, experience and an understanding of generally accepted valuation principles. The two primary types of business valuations that are widely used and accepted are income valuation and asset valuations. Market valuations are also used in some cases but their use is restricted because of the difficulty inherent in trying to compare two different companies.
Income valuations are based on the premise that the current value of a business is a function of the future value that an investor can expect to receive from purchasing all or part of the business. Income valuations are the most widely used type of valuation. They are generally used for valuing businesses that are expected to continue operating for the foreseeable future. In these valuations the expected returns from investing in the business and the risks associated with receiving the expected returns are evaluated by the appraiser. The appraiser then determines the value whereby a hypothetical buyer would receive a sufficient return on the investment to compensate the buyer for the risk associated with receiving the expected returns. Income valuation methods include the capitalization of earnings method, the discounted future income method, the discounted cash flow method, the economic income method and other formula methods. Asset valuations consider the business to be a collection of assets which have an intrinsic value to a third party in an asset sale. Asset valuations are typically used for businesses that are ceasing operation and for specific type of businesses such as holding companies and investment companies. Asset valuation methods include the book value method, the adjusted book value method, the economic balance sheet method and the liquidation method.
Market valuations are used to place a value on one business by using valuations that have been established for comparable businesses in either a public stock market or a recent transaction. This method is difficult to use properly because no two companies are exactly the same and no two transactions are completed for the exact same reasons. Market valuation methods include the price to earnings method, the comparable sales method, industry valuation methods and the comparable investment method.
When performing a business valuation, the appraiser is generally free to select the valuation type and method (or some combination of the methods) in determining the business value. Under the current procedures, there is no correct answer, there is only the best possible informed guess for any given business valuation. There are several difficulties inherent in this approach. First, the reliance on informed guessing places a heavy reliance on the knowledge and experience of the appraiser. The recent increase in the need for business valuations has strained the capacity of existing appraisal organizations. As a result, the average experience level of those performing the valuations has decreased. The situation is even worse for many segments of the American economy where experienced appraisers don't exist because the industries are too new. Another drawback of the current procedures for completing a valuation is that the appraiser is typically retained and paid by a party to a proposed transaction. It is difficult in this situation to be certain that the valuation opinion is unbiased and fair. Given the appraiser's wide latitude for selecting the method, the large variability of experience levels in the industry and the high likelihood of appraiser bias, it is not surprising that it is generally very difficult to compare the valuations of two different appraisers—even for the same business. These limitations in turn serve to seriously diminish the usefulness of business valuations to business managers, business owners and financial institutions.
The usefulness of business valuations to business owners and managers is limited for another reason—valuations typically determine only the value of the business as a whole. To provide information that would be useful in improving the business, the valuation would have to furnish supporting detail that would highlight the value of different elements of the business. An operating manager would then be able to use a series of business valuations to identify elements within a business that have been decreasing in value. This information could also be used to identify corrective action programs and to track the progress that these programs have made in increasing business value. This same information could also be used to identify elements that are contributing to an increase in business value. This information could be used to identify elements where increased levels of investment would have a significant favourable impact on the overall health of the business.
Another limitation of the current methodology is that financial statements and accounting records have traditionally provided the basis for most business valuations. Appraisers generally spend a great deal of time extracting, aggregating, verifying and interpreting the information from accounting systems as part of the valuation process. Accounting records do have the advantage of being prepared in a generally unbiased manner using the consistent framework of Generally Accepted Accounting Principles (hereinafter, GAAP). Unfortunately, these accounting statements have proved to be increasingly inadequate for use in evaluating the financial performance of modem companies.
Many have noted that traditional accounting systems are driving information-age managers to make the wrong decisions and the wrong investments. Accounting systems are "wrong" for one simple reason, they track tangible assets while ignoring intangible assets. Intangible assets such as the skills of the workers, intellectual property, business infrastructure, databases, and relationships with customers and suppliers are not measured with current accounting systems. This oversight is critical because in the present economy the success of an enterprise is determined more by its ability to use its intangible assets than by its ability to amass and control the physical ones that are tracked by traditional accounting systems.
The recent experience of several of the most important companies in the U.S. economy, IBM, General Motors and DEC, illustrates the problems that can arise when intangible asset information is omitted from corporate financial statements. All three were all showing large profits using current accounting systems while their businesses were falling apart If they had been forced to take write-offs when the declines in intangible assets were occurring, the problems would have been visible to the market and management would have been forced to act on them much sooner. These deficiencies of traditional accounting systems are particularly noticeable in high technology companies that are highly valued for their intangible assets and their options to enter new markets rather than their tangible assets.
The accounting profession itself recognizes the limitations of traditional accounting systems. A group of senior financial executives, educators and consultants that had been asked to map the future of financial management by the American Institute of Certified Public Accountants (AICPA) recently concluded that:                a) Operating managers will continue to lose confidence in traditional financial reporting systems,        b) The motto of CFOs in the future will likely be "close enough is good enough", and        c) The traditional financial report will never again be used as the exclusive basis for any business decisions.
The deficiency of traditional accounting systems is also one of the root causes of the short term focus of many American firms. Because traditional accounting methods ignore intangible assets, expenditures that develop a market or expand the capabilities of an organization are generally shown as expenses that only decrease the current period profit. For example, an expenditure for technical training which increases the value of an employee to an enterprise is an expense while an expenditure to refurbish a piece of furniture is capitalized as an asset.
The dependence on accounting records for valuing business enterprises has to some extent been a matter of simple convenience. Because corporations are required to maintain financial records for tax purposes, accounting statements are available for virtually every company. At the same time, the high cost of data storage has until recently prevented the more detailed information required for valuing intangibles from being readily available. In a similar manner, the absence of integrated corporate databases within corporations and the home-grown nature of most corporate systems has until recently made it difficult to compare similar data from different firms.
The lack of a consistent, well accepted, realistic method for measuring all the elements of business value also prevents some firms from receiving the financing they need to grow. Most banks and lending institutions focus on book value when evaluating the credit worthiness of a business seeking funds. As stated previously, the value of many high technology firms lies primarily in intangible assets and growth options that aren't visible under traditional definitions of accounting book value. As a result, these businesses generally aren't eligible to receive capital from traditional lending sources, even though their financial prospects are generally far superior to those of companies with much higher tangible book values."
The system disclosed in Eder then provides a system which measures the financial performance of all the elements of business value for a given enterprise by automating the extraction of transaction data from the databases, tables, and files of the existing computer-based corporate finance, operation, sales, and human resource software databases as required to operate the system. This resulted in a complex and cumbersome model that would likely miscalculate the value of the business due to a lack of a "reasonableness of assumptions" assessment that an experienced operator would apply in consideration as to the nature of the business and the industry in which the business operates for example.
In light of the preceding discussion, it is clear that it would be advantageous to provide a simple, easy to use valuation system which provides the advantages of the Eder system but based on reasonable assumptions from an experienced operator.
It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

Method of business valuation and data processing system


A primarily radial load ball bearing includes an assembly of outer and inner race rings having confronting raceways for a plurality of balls, and a unitary ball separator fabricated of a moldable material such as nylon. The separator is a ring-shaped member having an annular base and annularly spaced fingers projecting axially from the base to provide annularly spaced ball pockets. The separator is configured to be received between the races to separate and space the bearing balls in the bearing. The wall surfaces of the ball pockets may be spherical or may be cylindrical generated about radial axes of the separator. The effective diameter of the pocket wall surfaces is larger than that of the balls to provide a clearance space; and the wall surfaces are provided with projections of several configurations which define ball engaging surfaces having an effective diameter still slightly larger than that of the balls to provide minimal clearance with the balls.

This invention relates to ball separators for use in ball bearings; and more particularly to molded plastic ball separators having means to minimize ball pockets to ball clearance. The term "ball separator" refers to a component of a ball bearing assembly which is also commonly known by the names "ball retainer" and "bearing cage".
A problem with ball separators which are fabricated from molded plastic such as nylon for example, is that, if the clearance between the wall surfaces of the ball pocket and the ball is too small, the bearing will tend to heat up excessively due to the friction between the ball and the pocket wall surfaces, and consequently reduce lubrication. The bearing temperature may increase by 200.degree. F. for example. Excessive heating creates a particular problem in this type of bearing since the separator material expands much more rapidly with heat than the steel bearing races. The inherent result is that the radial expansion of the separator ring is significantly greater than the radial expansion of the races; and with a small clearance between the separator pockets and balls, this movement of the separator relative to the balls creates binding, and more friction, and more heat thereby aggravating the problem.
A related situation which further aggravates the problem is that where the ball sockets are spherical, the relatively sharp edges of the spherical pockets act to wipe lubricant from the balls; and this inherently results in less lubrication and increased friction. This problem is also further aggravated by the greater radial expansion of the separator relative to the races.
While these problems can be alleviated to some extent by increasing the ball to ball pocket clearance, this produces a relatively loose separator in the ball bearing; and this looseness of the separator may result in separator vibration and resultant noise. This separator noise may raise the overall bearing noise to an unacceptable level, particularly at high speed.
A principal object of this invention therefore is to provide a new and improved ball separator which overcomes the disadvantages of the prior art ball separators as discussed above.
Another object of this invention is to provide an improved molded plastic bearing separator with means to minimize ball to pocket wall surface clearance, and at the same time minimize ball to separator friction.
A further object of this invention is to provide an improved ball separator to minimize separator noise due to looseness of the separator, and to minimize heat buildup due to bearing to separator friction.
Still another object of this invention is to provide a molded plastic ball separator having pocket wall surface projections defining the ball engaging surfaces of the ball pockets.
These objects are accomplished in a ball separator for use in a ball bearing which includes an outer race, an inner race, and a plurality of spherical balls coacting with these races. The ball separator includes an annular base, and a plurality of annularly spaced fingers projecting generally axially from the base to define individual annularly spaced ball pockets. The ball separator has inner and outer side walls, and is configured to be received between the inner and outer races with its side walls confronting respective races. Each of the ball pockets is formed to partially enclose a respective ball, and has wall surfaces with an effective diameter larger than the diameter of a bearing ball, thereby providing clearance space between the pocket wall and the bearing ball. Each of the pocket wall surfaces has integral projections formed thereon which define ball engaging surfaces having an effective diameter slightly larger than the diameter of the ball to provide a small clearance between the projections and the ball.
More particularly, the projections for each pocket may comprise a plurality of ribs circumambienting the pocket and generally parallel with the separator side walls, a plurality of ribs traversing the wall surface of the pocket either substantially perpendicular to the separator side walls or inclined relative thereto, a plurality of relatively small pads which may be generally cylindrical in shape or dome-shaped, combinations of such ribs and pads, or traversing angled ribs which intersect one another to define lubricant retaining recesses in the wall surface.
Also more particularly the pocket wall surface may be cylindrical, being formed about a generally radial axis of the separator, or the surface may be spherical.
The novel features and the advantages of the invention, as well as additional objects thereof, will be understood more fully from the following description when read in connection with the accompanying drawings.


Systems and method are provided for generating a record of a medical procedure. A system includes a processor and a non-transitory computer readable medium. The medium includes a graphical user interface configured to display a graphic representing an anatomical region of a patient and accept a gesture from a user comprising a selected procedure and, diagnosis when appropriate, and a location on the displayed anatomical region. A knowledge base stores a plurality of templates, each comprising a set of fields. A record generation engine selects an associated one of the plurality of templates according to each of the selected procedure and, diagnosis when appropriate, and the location on the displayed anatomical region and populates the set of fields associated with the selected template. A database interface formats the populated template into a database record suitable for an electronic health records database associated with the system.

An electronic health record (EHR), or electronic medical record (EMR), is a systematic collection of electronic health information about an individual patient or population. It is a record in digital format that is theoretically capable of being shared across different health care settings. In some cases, this sharing can occur by way of network-connected, enterprise-wide information systems and other information networks or exchanges. EHRs may include a range of data, including demographics, medical history, medication and allergies, immunization status, laboratory test results, radiology images, vital signs, and personal statistics like age and weight.

Graphical generation and retrieval of medical records


An article of flashing for a deck includes a channel with a back leg, a first side leg, and a second side leg and further includes an attachment flange fixedly connected to the channel where the channel is adapted to receive decking. A deck flashing system includes a deck with a surface and at least one edge, decking forming the surface of the deck, and flashing extending along the at least one edge, the flashing having a channel adapted to receive the decking. A method of trimming a deck includes erecting deck framing, installing decking on the framing, and installing flashing on at least one edge or the entire perimeter of the deck.

Deck construction is continually evolving and materials and methods are continually changing. Current residential and commercial applications often involve using composite materials for the decking surface, skirt boards, railings, and other areas of a deck. These composite materials are used in exposed areas for their aesthetic appeal but also because of their alleged maintenance free characteristics. However, composite materials are subject to expansion and contraction due to changes in temperature, which can cause multiple issues with the maintenance of the decking and the framing it is attached to.
Deck construction methods naturally create multiple seams across the surface of the deck as well as gaps to allow for drainage. Debris can become trapped in between the composite materials in these seams and gaps. As the composite materials expand and contract, the debris can be compressed against adjacent surfaces causing unintended shifting and movement. In a particular instance, where a skirt board at the edge of a deck extends up along the edge of the deck surface, the lateral expansion of the decking can simply push the skirt board away from the deck. This unintended shifting and movement can cause members of the deck to become unseated or even loose leading to squeaking and further intrusion of debris and worse yet, moisture.
In many cases, decks are supported off of a ledger board attached to the exterior face of a building. In recent years, increasing numbers of deck failures have occurred due to moisture intrusion in and around these ledger boards. Moreover, moisture intrusion generally has become an increasing concern in building construction.
There is a need in the art for a device or system capable of both accommodating the expansion and contraction issues of composite decking materials as well as preventing the intrusion of debris and moisture. Additionally, there is a need for this device or system to remain consistent with the aesthetic appeal of the deck to which it is applied.