CA2253098A1 - Process for producing reactive silane oligomers - Google Patents
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Abstract
The invention is directed to a process for making a reactive silane oligomer having low polydispersity, viscosity and volatility. The process utilizes reacting unsymmetrical difunctional silane monomers with water, diol monomers, or a combination thereof to make the reactive silane oligomer. The unsymmetricaldifunctional silane monomers are with silane reactive groups having significantly different reactivities. Use of such reactive silane oligomers results in multi-component coating compositions having high miscibility, low VOC, low viscosity and high percentage of solids.
Description
CA 022~3098 1998-11-09 TITLE
PROCESS FOR PRODUCING
REACTIVE SILANE OLIGOMERS
Ba~k~round Of The Invention This invention concerns a composition comprising reactive silane oligomers having low polydispers ty, viscosity and volatility. Such oligomers are useful for multi-component silicon modified organic co~tings with low volatile organic content (VOC), improved mar and etch resistance.
A number of clear and pigmented coating coll.posilions are utilized in various coatings, such as, for example, automotive coatings. Such coatings, typically applied as OEM coatings (original e~ l manufacturer), are generally solvent based. However, due to increasing conccl~l over the excessive release of volatile organic co.llponent (VOC) in the atmosphere, significant research is being conducted for developing low VOC, solvent-based coating compositions, generally with less than 0.6 kilograms of organic solvent per liter of coating composition (5 pounds per gallon), as determined under ASTM D3960 Test.
One of the approaches used in reducing the amount of VOC released by a coating composition during its application on a substrate, such as an automobilebody, involves adding a silicon-containing reactive diluent to the coating composition. A number of patents disclose low VOC silicon-containing curable coating compositions, such as, for example, U.S. Patent 4,467,081.
However, none of the approaches disclosed in the prior art improves miscibility in multi-component formulations while still m~int~ining OptilllUIll balance of coating p~ope- lies, such as good mar and chemical resistance, high gloss and durability. Further limiting factor in the use of silane-based reactive diluents in coating compositions is the poor process control of silane functionalities during the ~lcpal~lion of conventional reactive ~ ent.~, which results in a broad distribution of silane functionalities.
The present invention ovelcolnes the foregoing problems, by providing low VOC silane-based coating compositions that result in coqtings having improved mar, chemical and envh~onl--ental etch re~i~t~ e, a~pea.a,lcc and durability while still providing improved miscibility in multi-cGmponent formulations, as compared to conventional coating co.-.l)osilions.
Statement Of In-~ention The present invention is directed to a process for making a reactive silane oligomer, said process comprising:
CA 022~3098 1998-11-09 ~ contacting one or more unsymmetrical difunctional silane monomers with water, with one or more diol monomers, or with a combination thereof, wherein:
said diol monomer is:
Rl -(OH)z, wherein Rl is selected from the group consisting of:
a) C2 to C20 alkylene, cycloaliphatic ringS or aromatic rings, each optionally substituted with at least one member selected from the group consisting of O,N,PandS;
b) two or more cycloaliphatic or aromatic rings connected to each other through a covalent bond, or through an alkylene group of 1 to 5 carbon atoms, orthrough a heteroatom, or fused together to share two or more carbon atoms, each optionally substituted with at least one member selected from the group consisting of O, N, P and S; and c) a linear polyester, branched polyester, a combination of said linear and said branched polyesters, polyacrylate, polyolefin, polyether, polycarbonate, polyurethane, or polyamide, each having a GPC weight average molecular weight in the range of from about 200 and 10,000; and said difunctional silane monomer is:
H H
XPYP25i--Cp--R2_Cs--SiYs2Xs wherein Cp is a primary carbon atom, Cs is a secondary carbon atom and R2 is selected from the group consisting of:
a) C3 to C20 alkylene, C~ to C~0 alkyl substituted cycloaliphatic rings or C~ to Cl0 alkyl substituted aromatic rings, each optionally substituted with at least one member selected from the group consisting of O, N, P and S;
b) Cl to Clo alkyl substituted two or more cycloaliphatic rings, or Cl to C1o alkyl substituted two or more aromatic rings conn~cte~l to each other through a covalent bond, or through an alkylene group of 1 to 5 carbon atoms, or through aheteroatom, or fused together to share two or more carbon atoms, each optionallysubstituted with at least one member selected from the group con~icting of O, N, P
and S; and c) a combination of (a) and (b);
R3, R4 and Rs each is independently selected from the group consisting of:
Hydrogen, C~ to C20 alkyl, C~ to C~0 alkyl substituted cycloaliphatic rings or C, to C,0 alkyl substituted aromatic rings, each optionally substituted with at least one member selected from the group consisting of O, N, P and S;
CA 022~3098 1998-11-09 XP and Xs being independently selected from the group consisting of alkoxy containing I to 20 carbon atoms, acyloxy containing 1 to 20 carbon atoms,- phenoxy, halogen, amine, amide, urea, imidazole, carbamate, ketoximine, oxazolidinone, and a combination thereof; and YP and Ys being independently selected from the group consisting of alkyl containing 1 to 12 carbon atoms, alkoxy containing 1 to 20 ~arbon atoms, acyloxycontaining I to 20 carbon atoms, phenoxy, halogen, amine, amide, urea, imidazole, carbamate, oxazolidinone, and a combination thereof;
for producing said reactive silane oligomer having a GPC weight average molecular weight of less than 10,000 and having a polydispersity of less than 3.The present invention is also directed to a reactive silane oligomer of the forrnula:
XsY 52Si _~5--R2 _(;p--SiYP2 --O--Rl--O--SiYP2 --~p--R2--l~s--SlYs2Xs Rs_~--R3 H H R --~--R
when the unsymmetrical difunctional silane monomer is contacted with the diol monomer in the foregoing process.
The present invention is also directed to a reactive silane oligomer of the formula:
XsYS2Si--Cs--R2_Cp--SiYP2 0--SiYP2--Cp--R2_Cs--SiYs2Xs when the unsymmetrical difunctional silane monomer is contacted with water in the foregoing process.
The present invention is further directed to a coating colllposilion containing the reactive silane polymer made in ac~ ce with the foregoing process.
The present invention advantageously provides for a low VOC coating composition having high solids content.
The process of the present invention optimally and efficiently converts the re~t~ntc into a reactive silane oligomer having lower polydi~ ily, viscosity andvolatility than a conventional silane oligomer.
The process of the present invention further advantageously produces a re~tive silane oligomer having a low GPC weight average molecular weight of less than 10,000. Such a reactive silane oligomer, when included as a reactive diluent in a coating composition, lowers VOC while .cimlllt~nçously in~ ,asing the CA 022~3098 1998-11-09 solids content of the composition. As a result, users can efficiently apply suchcoating compositions by conventional means, such, as by spraying, dipping, roller coating, brushing or by electro-coating, and still produce durable coatings withlow mar, etch and chemical resistance, and glossy appearance on conventional 5 substrates, such automotive bodies.
Detailed Description of the Invention As used herein:
"High solids composition" is a coating composition having more than 40 weight percent, preferably in the range of from 60 to 100 weight percent of total 10 solids based on the total weight of the composition.
"Low VOC composition" is a coating composition having less than 0.6 kilograms of solvent per liter of the coating composition.
"Low viscosity composition" is a coating composition having viscosity in the range of from I to 10,000 centipose as measured under ICI cone and plate 1 5 viscometer.
"GPC weight average molecular weight" means weight average molecular weight as determined by gel permeation chromatography (GPC) using polystyrene standard.
"Polydispersity" means GPC weight average molecular weight divided by 20 GPC number average molecular weight.
"Reactivity" means a degree of chemical activity of silane groups attached to carbon atoms in the backbone of a silane monomer.
"Primary carbon atom (Cp)" is a carbon atom in the backbone, shown below, of an unsymmetrical difunctional silane monomer having only one carbon 25 atom attached to it.
IH
I P
H
"Secondary carbon atom (Cs)" is a carbon atom in the backbone of the unsymmetrical difunctional silane monomer, shown below, having one hydrogen atom and two carbon atoms attached to it.
CA 022~3098 1998-11-09 I S--I
-f It is believed, without reliance thereon, that the presence of two carbon attached to Cs, due to steric factors, makes the silane groups attached to Cs chemically less reactive than the silane groups attached to Cp. The presence of Cp S and Cs, preferably provided with the same silane groups (SiY2X), produces the asymmetric reactivity in the unsymmetrical difunctional silane monomer.
This invention is directed to a process for making reactive silane oligomers having low polydispersity of less than 3. Inclusion such reactive silane oligomers in a coating composition results in a low VOC coating composition having low 10 viscosity and high solids. The process utilizes unsymmetrical difunctional silane monomers preferably provided with two structurally identical silane reactive groups attached to Cs and Cp for inducing significantly different reactivities, mostly resulting from the steric factors. The process of the invention results in a low dispersity reactive silane oligomer having low GPC weight average molecular weight in the range of 200 to 10,000, preferably in the range of from 400 to 5000, and more preferably in the range of from 500 to 2000. The polydispersity of the reactive silane oligomer is in the range of from 1.1 to 3, preferably in the range of from I.1 to 1.8, and more preferably in the range of from 1.1 to 1.5.
The process of the invention includes contacting one or more unsymmetrical difunctional silane monomers with one or more diol monomers or with water, or with a combination thereof, to produce the reactive silane oligomer.
The preferred reactive silane oligomers are dimers resulting from the reaction of disilane monomers with water and trimers resulting from the reaction of a disilane monomers with diol monomers.
The diol monomer suitable for use in the present invention is typically provided with a hydroxyl equivalent weight in the range of from 30 to 2500, preferably in the range of from 50 to 500 and has the following formula:
Rl-(OH)2 (I) Rl group in foregoing formula I may include:
(a) C2 to C20 alkylene; aromatic or preferably cyclo~liph~tic rings.
Some of the suitable C2 to C20 alkylene include ethylene, propylene, butylene, pentylene and hexylene groups.
Some of the suitable cycloaliphatic ring groups include cyclopentylene, cyclohexylene, terpinylene. Cyclohexylene is preferred.
.
CA 022~3098 1998-11-09 - Some of the suitable aromatic ring groups include phenylene, naphtylene, anthracylene.
Each member in the foregoing (a) group may optionally be substituted with at least one member selected from the group consisting of O, N, P and S, N and O5 are preferred, O is more preferred.
Some examples of the simple diols include 2,3-dimethyl-2,3-butanediol(pinacol), 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2-ethyl-2-methyl-1,3-propanediol, 2,5-dimethyl-2,5-hexanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, l,10-dec~rle-liol, 10 1,12-dodecanediol, and cycloaliphatic diols such as 1,4-cyclohe~ e-~im~.thanol, 4,4'-isopropylidenedicyclohexanol, 4,8-bis(hydroxymethyl)tricyclodecane.
Neopentyl glycol and cycloaliphatic diols, such as 4,4'-isopropylidenedicyclohexanol are preferred.
R' may also include:
(b) 2 to S, preferably 2 to 3, cycloaliphatic rings or aromatic rings connected to each other through a covalent bond, or through an alkylene group ofI to 5 carbon atoms, or through a heteroatom, or fused together to share in the range of from 2 to 8 carbon atoms. The cycloaliphatic rings or aromatic rings connected to each other through the alkylene group or the covalent bond are 20 preferred, those connected through the alkylene group are more preferred. Thecycloaliphatic rings or aromatic rings suitable for the foregoing group are the same as those described earlier.
Each member in the foregoing (b) group may optionally be substituted with at least one member selected from the group consisting of O, N, P and S. O
25 and N are preferred, O is more preferred.
Rl may also include:
(c) a linear polyester, branched polyester, a combination of the linear and the branched polyesters, polyacrylate, polyolefin, polyether, polycarbonate, polyurethane, or polyamide group, each having a GPC weight average molecular 30 weight in the range of from about 300 and 10,000, preferably in the range of from 300 to 4000, more preferably in the range of from 300 to 3000.
Linear polyester diols are generally known and are prepared by conventional methods using simple diols known in the art, including but not limited to the previously described simple diols and dicarboxylic acids. Examples 35 of suitable dicarboxylic acids include but are not limited to: hexahydro-4-methylphtalic acid; hexahydrophtalic acid; phtalic acid; isophtalic acid;
terephtalic acid; adipic acid; azelaic acid; sebasic acid; succinic acid; maleic acid;
glutaric acid; malonic acid; pimelic acid; suberic acid; fumaric acid; and itaconic CA 022~3098 1998-11-09 acid. Anhydrides of the above acids, where they exist, can be also employed and are encompassed by the term "dicarboxylic acids".
In addition, multifunctional monomers which contain both hydroxyl and carboxyl functionalities, or their derivatives are also useful. Such monomers 5 include but are not limited to:
Lactones, such as, caprolactone, butyrolactone, valerolactone, propiolactone; and hydroxyacids, such as, 2-hydroxyc~,oic acid.
Polyester diols are preferably prepared by first reacting simple diols known in the art, including but not limited to the previously described simple diols, with 10 diacid anhydrides known in the art, including but not limited to the previously described anhydrides. One of the preferred polyester diol is prepared by reacting hexahydromethylphtalic anhydride with water to provide a co,~ onding dicarboxylic acid. Such a dicarboxylic acid when reacted with an alkylene oxide,preferably with the glycidyl esters of organic acids, such as, for example, 15 CARDURA-E~ glycidyl ester, supplied by Shell Chemical Company, Houston, Texas, results in a preferred polyester diol.
Polyether diols are generally known and are plc~a~ed by conventional methods, typically by the ring opening polymerization of cyclic ethers, acteals, or a combination thereof. Cyclic ethers are known in the art, such as, for example,20 epoxides (having a 3 member ring), oxetanes (having a 4 member ring), furanes(having a 5 member ring) and higher cyclic ethers having in the range of from 6 to 10 member rings. Ethylene and propylene oxide and tetrahydlorul~le are preferred, tetrahydrofurane is more preferred. Optionally, simple diols, such as, those described previously, may be used for introducing the hydroxyl end groups 25 and for controlling the molecular weight of the polyether diols. Examples of useful polyether polyols include the generally known poly(tell~lethylene oxide) diols, available commercially as TERATHANE0 poly(tetla~llethylene oxide) diol, supplied by DuPont Company of Wilmington, Delaware. TERATHANE~
poly(tetramethylene oxide) diol is prepared by polymerizing tetrahydrofurane in 30 the presence of cationic catalysts. Other useful polyether diols also include the poly(propylene oxide) diols prepared by cationic or anionic polymerization or copolymerization of propylene oxide. The simple diols known in the art, including but not limited to the previously described simple diols may be used as initiators or telogens to provide controlled linear structures to the r~-snlting35 polyether diols.
Linear amide-cont:~ining diols are generally known and are typically prepared by analogous processes described previously in the plt;l)~a~ion of the polyester diols from any of the aforedescribed diacids, diols or lactones.
CA 022=,3098 1998-11-09 Additional amounts, in the range of from 10 to 80, preferably in the range of from 20 to 70, all in weight percentages based on the total weight of monomer mixture, of diamines, aminoacids, lactams, or aminoalcohols or a combination thereof are also typically utilized.
Polycarbonate diols are generally known and are prepared conventionally by reacting previously described simple diols with carbonates. Aliphatic polycarbonate diols may also be prepared from 1,3-dioxan-2-one or derivatives thereof. Current conventional methods for the pl.,palalion of the aliphatic polycarbonate diols include tr~n~estçrification of simple diols with lower 10 carbonates of dialkyl preferably having in the range of from 1 to 4 carbon atoms;
dioxolanones; or diphenyl carbonates, in the presence of conventional catalysts,such as alkali metal, tin, and titanium compounds.
Polyurethane diols are generally known and are prepared conventionally by reacting previously described simple diols, polyester diols, amide-containing 15 diols, polycarbonate diols, polyhydrocarbon diols with organic polyisocyanates.
The organic polyisocyanate can be reacted with the diol either directly to form the polyurethane diol or by the generally known prepolymer method wherein the diol and polyisocyanate are reacted in relative plopollion to first produce an isocyanate terminated prepolymer with subsequent reaction of the prepolymer with the same 20 or different additional diol to form the polyurethane diol. The polyisocyanate which is reacted with the diol may be any organic polyisocyanate such as, for example, aromatic, aliphatic, cycloaliphatic, or heterocyclic polyisocyanate, which may be unsubstituted or substituted with alkyl groups, preferably having 1 to 4 carbon atoms. Many such organic polyisocyanates are generally known, examples 25 of which include: toluene diisocyanate isomers, diphenylmethane diisocyanate isomers, biphenyl diisocyanate, tetramethylene-1,4-diisocyanate, hexamethylene-1,6-diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate isomers, hexahydrotoluene diisocyanate isomers and mixtures thereof.
Polyhydrocarbon diols are generally known and are prepared 30 conventionally by polymerizing simple olefins, such as isoprene, butadiene and styrene usually, in the presence of difunctional anionic initiators, followed byhydroxylation with epoxides. Alternatively, such simple olefins may be polymerized in the presence of multifunctional cationic initiators for monomers,such as isobutylene or styrene, followed by hydroxylation of olefin t~nnin~l 35 groups. Polyhydrocarbon diols are generally known and available commercially, as KRATON LIQUI~ polyhydrocarbon diol, supplied by Shell Chemical Company, Houston, Texas.
CA 022~3098 1998-11-09 Most preferred diol monomers include 1,4 cyclohexane dimethanol, hydrogenated bisphenol A, or a combination thereof.
The unsymmetrical difunctional silane monomers suitable for use in the present invention has a weight average molecular weight in the range of from 300S to lS00, preferably in the range of from 350 to 1000. It is of the following formula:
IH IH
XY2Si--Cp--R2_Cs--SiY2X
R (II) In formula II, Cp is a primary carbon atom and Cs is a secondary carbon atom. R2 in formula II is selected from one or more of following:
a) C3 to C20 alkylene, C~ to C~o alkyl substituted cycloaliphatic rings or Cl to C~0 alkyl substituted aromatic rings, Each member in the foregoing (a) group may optionally be substituted with at least one member selected from the group consisting of O, N, P and S. O and Nare preferred, O is more preferred.
b) C~ to Clo alkyl substituted two or more cycloaliphatic rings, or Cl to C10 alkyl substituted two or more aromatic rings connected to each other through a covalent bond, or through an alkylene group of 1 to 5 carbon atoms, or through aheteroatom, or fused together to share two or more carbon atoms, Each member in the foregoing (b) group may optionally be substituted with at least one member selected from the group consisting of O, N, P and S. O
and N are preferred, O is more preferred; and c) a combination of (a) and (b).
Preferred (a) in the foregoing R2 are cyclohexylene and terpinylene, more preferred being cyclohexylene.
Preferred (b) in the foregoing R2 is norbornylene.
R3, R4 and R5 each is independently selected from the group consisting of:
Hydrogen, Cl to C20 alkyl, Cl to C~0 alkyl substituted cycloaliphatic rings or Cl to C~0 alkyl substituted aromatic rings, each optionally substituted with at least one member selected from the group consisting of O, N, P and S, O and N
30 are preferred and O is more preferred.
XP and Xs each in formula II is independently selected from the group consisting of alkoxy containing 1 to 20 carbon atoms, acyloxy cont~ining 1 to 20 carbon atoms, phenoxy, halogen, amine, amide, urea, imidazole, carbamate, ketoximine, imidazole, oxazolidinone, and a combination thereof.
CA 022~3098 1998-11-09 YP and Ys each in formula II is independently selected from the group consisting of alkyl containing 1 to 12 carbon atoms, alkoxy containing 1 to 20 carbon atoms, acyloxy containing 1 to 20 carbon atoms, phenoxy, halogen, amine, amide, urea, imidazole, carbamate, ketoximine, oxazolidinone, and a combination S thereof. Alkoxy is preferred and methoxy is more preferred.
Examples of the preferred unsymmetrical difunctional silane monomers include but are not limited to bis(trimethoxysilyl) derivatives of the followingpolyolefins: limonene and other terpines, 4-vinyl-1-cyclohexene, S-vinyl-2-norbornene. The preferred unsymmetrical difunctional silane monomers include 10 4-(2-trimethyoxysilylethyl)-1-trimethoxysilylcyclohexane, S-(2-trimethoxysilylethyl)-trimethoxysilyl norbornane, or a combination thereof.
When the diol monomers are contacted with the unsymmetrical difunctional silane monomers in accordance with the process of the present invention, resulting reactive silane oligomers usually contain variable levels, 15 generally in the range of from I to lO0 weight percent, preferably in the range of from 3 to 80 weight percent based on the total weight of monomer mixture of their corresponding hydrolysis and condensation products from the reaction with water,which may be added purposely or may be adventitiously introduced from the ambient moisture or with other components, particularly with the diol monomers 20 whose commercial grades usually contain significant levels of water. As a result of the aforedescribed hydrolysis/condensation processes more stable -Si-O-Si-linkages are advantageously introduced in the resulting reactive silane oligomeralong with an increase in weight average molecular weight, and a relative reduction in viscosity compared over convention reactive silane oligomers 25 prepared from symmetrical disilane monomers The oligomerization of the diol monomers with the difunctional silane monomers resulting in the C-O-Si formation is an equilibrium process. As a result, the output of the process can be controlled to achieve higher yield of the desired Rl-C-O-Si-R2 by using a stoichiometric excess of the difunctional silane30 monomers, removing a volatile X-H byproduct from the reaction mixture, or by utilizing both of the foregoing steps.
The silylation/oligomerization of the diol with disilane mol~ol"el~ usually results in a complex mixture composed of various oligomers and isomers, shown by mass spectrographic analysis. This is due to the random nature of the silylation 35 involving multifunctional reactants and a contribution of the silane hydrolysis/condensation processes, usually due to the adventitious formation of water. An attractive coating plop~l~y balance invention, such as scratch, chemical etch resistance and appearance, of a coating composition containing the reactive CA 022~3098 1998-11-09 silane oligomer of the present invention is often obtained by a narrow operational window of a specific product mixture composition. The oligomer composition can be varied widely by the molar ratio of the reactants and the extent of the oligomerization controlled by the catalyst choice, reaction time and reaction 5 temperature.
Thus, the process of the present invention may be further improved by any one or a combination of the following steps for producing the reactive silane oligomers:
I. By adjusting the reactivity ratio (CptCs) between the silane groups (XY2Si-) attached to Cp and Cs in the range of from 1.1 to 100,000, preferably in the range of 1.1 to 10,000, more preferably in the range of from 2 to 1000. It was unexpectedly discovered that by utilizing the difference between the higher reactivity of the silane group attached to the Cp and the lower reactivity of the identical silane group attached to the Cs, the reactive silane oligomers of the present invention are produced. The reactivity ratio may be further increased bysubstituting one or more hydrogen atoms on carbon atoms connected to Cs with moieties selected from the group consisting of Cl to C20 alkyl or aryl groups, or a combination thereof. Cl to C20 alkyl groups are plc;felled.
II. By adjusting the molar ratio of disilane to hydroxy groups in the range from 0.7 to 4, preferably in the range of from 0.7 to 3, more preferably in the range of from 0.9 to 1.4 between:
i) the difunctional silane monomers and 2 times water, ii) the difunctional silane monomers and 2 times the diol monomers, or iii) difur~tional silane Ill~)l~lllelD
2 (water and diol Illo~ D) III. By increasing the conversion of the unsymmetrical difunctional silane monomers into the reactive silane oligomer in the range of from 50 percent to 100 percent, preferably in the range of from 60 percent to 95 percent, more preferably in the range of from 65 percent to 90 percent. The foregoing increase in the conversion is accomplished by increasing the catalyst reactivity and concentration, increasing the reaction tel,lpe,~tule during the oligomerization, and increasing the reaction time.
IV) By utili7ing a combination of said steps I, II, and m.
The reaction may be carried out with or without a catalyzing amount of a catalyst, primarily depending on the reactivity of the SiX. The catalyzing amount of the catalyst used is typically in the range of from 0.01 percent to 5 percent, preferably in the range of from 0.01 percent to 2 percent and more preferably inthe range of from 0.01 percent to 0.5 percent, all in weight percentages based on ll CA 022~3098 1998-11-09 the total weight of starting reaction mixture. It is desired for the storage stability, particularly moisture stability to prepare the reactive silane oligomer essentially free of a catalyst. Therefore, catalysts which can be effectively and conveniently removed from the products, by conventionally means, such as ion exchange or S absorbing media, are preferred. Particularly useful catalysts include heterogeneo~s catalysts, such as, fluoroalkylsulfonic acid NAFION~9 NR-50 supplied by DuPont Company of Wilmington, Delaware, which can be easily separated from the product. Other preferred catalysts are volatile catalysts, such as, trifluoroacetic acid; amines or thermofugitive catalysts, such as, 10 tetraalkylammonium hydroxides, which can be substantially removed by a post-heating. Many other useful catalysts can be employed and can be optionally removed by passing the product through an app.o~liate ion exchange or absorbing media. Examples of other useful catalysts include but are not limited to, essentially any medium or strong acids with pKa below 8, preferably in the range15 of from 2 to 5, such as, sulfonic acids; alkali bases; ammonium salts; tin containing compounds, such as, dibutyltin dilaurate, dibutyltin ~ cet~te, dibutyltin dioctoate and dibutyltin dioxide; titanates, such as, tetraisopropyl titanate, TYZOR~ tetrabutyl titanate supplied by DuPont Company of Wilmington, Delaware, aluminum titanate; aluminum chelates, and zirconium 20 chelate.
Typically the silylation reaction is conducted in a substantially moisture free atmosphere, usually under a blanket of an inert dry gas, such as nitrogen. The reaction mixture which includes the diol and disilane monomers, optionally with a catalyst, is heated for several hours, typically in the range of from 3 to 8 hours, at a 25 temperature ranging from 60~C to 200~C with the ~ till~tion and removal of the low boiling, volatile reaction byproduct, such as an alcohol, typically methanol.
The progress of reaction is monitored by measuring the amount of the byproduct alcohol collected, reaction mixture viscosity changes, and optionally by substrate conversion and product formation by using conventional gas chromatography, 30 nuclear mass resonance and mass spectroscopy. Optionally, to minimi7- color in the resulting reactive silane oligomer, some conventional methods may be employed, such as, by adding anti-color additives cont~ining active P-H groups to the reaction mixture or by filtration of the reaction mixture through active carbon, silica or other standard decolorizing media. To reduce the VOC of the resnlting 35 reactive silane oligomer, the process of the invention is preferably carried in the absence of solvent. However, to further reduce the viscosity of the oligomer, a small amount, generally less than 50 percent by weight percent based on the total weight of composition of an organic solvent, such as aliphatic hydrocarbon, CA 022~3098 1998-11-09 preferably methylethyl ketone, xylene, ether, ester may be added. Typically, thereactive silane oligomer made by the process of the present invention useful forhigh solids coatings has viscosity in the range of from 1 to 10,000, preferably in the range of from 10 to 5000, more preferably in the range of from 10 to 5000, all 5 in centipoise as measured by using ICI cone and plate viscometer supplied by Gardner Laboratory.
The reactive silane oligomers are generally storage stable. To enhance the storage stability, the reactive silane oligomers are preferably stored in airtight containers to prevent the introduction of moisture. Thus, conventional moisture 10 scavengers, such as, orthoformates, orhto~ret~tes or some alcohols, p,~;feldbly propanol or butanol may optionally be added to further extend the storage stability. The storage stability may be further enh~n~e~l by storing the reactive silane oligomers in sealed containers under dry inert gas, such as, nitrogen.
Moreover, it is desired for improved storage stability to have the stored reactive 15 silane oligomers to be essentially free of any catalyst that were used during the oligomerization process.
The present invention is also directed to a reactive silane oligomer made according to the process of the invention. Thus, a reactive silane oligomer of the following formula is obtained when the unsymmetrical difunctional silane 20 monomer is contacted with the diol monomer:
XsY 525i --/~5--R2 _~p--siyP2 --O--R --O--SiYP2 It;p R ~s SiY 2X
Rs--~--R3 H /;
A reactive silane oligomer of the following formula is obtained when the unsymmetrical difunctional silane monomer is contacted with water:
XsYs25i--Cs--R2_Cp--SiYP2 0--SiYP2--Cp--R2_Cs--SjyS Xs Reactive silane oligomer mixtures, particularly first order homologs enriched in low molecular weight oligomers, preferably with GPC weight average molecular weight in the range of from 500 to 3000 are preferred.
The present invention is further directed to a coating colllposilion, such as, an automotive coating composition, cont~ining the reactive silane oligomer, as areactive diluent. Typically, the coating composition contains in the range of from 3 to 90, preferably in the range of from 10 to 90 and more preferably in the range _ CA 022~3098 1998-11-09 of from 20 to 80, all in weight percentages based on the total weight of the composition of the reactive silane oligomer to produce a coating composition having high solids in the range of from 40 percent to 100 percent, preferably in the range of from 50 percent to 100 percent and more preferably in the range of from60 percent to 100 percent; low viscosity in the range of from 10 to 3000, preferably in the range of from 10 to 2000 and more preferably in the range of from 10 to 1000, all in centipoise. B, using the reactive silane oligomers of the present invention in a multi-component coating composition, the degree of miscibility of the multiple polymeric components of such a coating composition is 10 significantly improved.
The coating composition containing the reactive silane monomer may contain additional conventional additives in suitable amounts. Such additives include pigments, stabilizers, rheology control agents, flow agents, toughening agents and fillers. The use of such additional additives will, of course, depend on 15 the intended use of the coating composition. Fillers, pigments, and other additives that would adversely effect the clarity of the cured coating will not be included if the composition is intended as a clear coating.
The reactive silane oligomers made in accordance with the process of this invention is suitable for coating compositions containing a variety of conventional 20 binders, such as, acrylic polymers as solutions or dispersions; polyisocyanates;
polyolefins, polyesters.
If desired, the coating compositions containing the reactive silane oligomer may also include conventional co-solvents, generally organic solvents in amountsthat do not produce high VOCs. Some of such solvents are aromatic 25 hydrocarbons, such as, petroleum naphtha or xylenes; ketones, such as, methylamyl ketone, methyl isobutyl ketone, methyl ethyl ketone or acetone; esters, such as, butyl acetate or hexyl acetate; and glycol ether esters, such as, propylene glycol monomethyl ether acetate.
The reactive silane oligomers are particularly suitable for coating 30 compositions used in automotive OEM and re~lni~h~s, as primers, basecoats, undercoats and overcoats. These oligomers may be also used as reactive diluents in high solids coating compositions used in marine applications, Illailll~.,ancecoatings, or coating compositions, such as those used in coating metal substrates, such as steel and aluminum or non-metallic substrates, such as, wood and 35 concrete.
CA 022~3098 1998-11-09 EXAMPLES AND PROCEDURES
F,Y~nPIe 1 (Dif ~nct~ al Silane Monomer 1) A 2-neck 100 ml round-bottom flask was equipped with a magnetic stirring bar, heating mantle, solids addition funnel, and condenser. The condenser was fitted with a Claisen adapter and a polytetrafluoroethylene-clad thermocouple was inserted through the Claisen adapter and cond~nser to reach the liquid layer of the flask. The other arm of the Claisen adapter was connected to a 50 ml liquid addition funnel fitted with a Dewar condenser. The entire assembly was purged with nitrogen prior to the reaction and a positive pressure of nitrogen was 10 maintained during the reaction.
The round bottom flask was charged with 4-vinyl-1-cyclohexene (22 g, 0.20 mole). The solids addition funnel was charged with 3g of Vazo~64 initiator,supplied by DuPont Company of Wilmington, Delaware. The liquid addition funnel was charged with trichlorosilane (57 g, 0.42 mole). The condenser on the 15 flask and the condenser on the solids addition funnel were cooled to - 10~C.
Stirring was started and the flask contents were heated. Once the flask temperature exceeded 90~C, enough trichlorosilane was added to bring the flask temperature to about 85~C. Small quantities of Vazo~64 initiator from the solidsaddition funnel were added intermittently to the reaction mixture. The 20 telllpelature was maintained between 85-95~C by adding trichlorosilane and small amounts of the initiator as needed.
Excess trichlorosilane in the reaction mixture was evaporated by passing nitrogen over the reaction mixture and recondensing trichlorosilane in the liquid addition funnel. At this point, the temperature was allowed to rise to 125~C, then 25 held for 1 hour. The total reaction time was 15 hours. The reaction mixture was then cooled to ambient temperature and the product isolated by standard inert atmosphere techniques. After isolation, the GC analysis, using decane as an internal standard, indicated that the vinylcyclohexene was consumed giving both monosubstituted product: 4-(2-trichiorosilylethyl)cyclohex-1-ene and isomers 30 thereof and disubstituted product: 4-(2-trichlorosilylethyl)-1-trichlorosilylcyclohexane and isomers thereof. Bis(trimethoxysilylated) reactivemonomer, namely 4-(2-trimethoxysilylethyl)-1-trimethoxysilylcyclohexane (4-VCHSi2), was obtained by a conventional methoxylation of the reaction mixture and then isolated by a vacuum lli.ctill~tion.
ExamPle 2 (Difunctional Silane Monomer 2) A mixture of 5-vinyl-2-norbornene (100 g, 0.83 mole), trichlorosilane (320 g, 2.36 mole) and platinum divinyl complex supplied by Gelest, Inc., of Tullytown, Pennsylvania (0.6 g 2-3 % in xylene) was heated in a pressure reactor CA 022~3098 1998-11-09 at 115~C for 4 hours. The excess trichlorosilane was stripped under vacuum. A
gas chromatography analysis showed the disilylated product purity to be greater than 96 %. To the reaction product ,a mixture of anhydrous methanol (115 g, 3.6 mole) and trimethylorthoformate (530 g, 5.0 mole) was added dropwise under vacuum. After the addition was complete, triethylamine (15 g, 0.15 mole) was added and the reaction mixture was refluxed for 2 hours. The volatiles were distilled off and the solids were filtered off. The reaction mixture was distilled at 80-100~C under a vacuum of 0.03-0.10 Torr, collecting about 10 % of the first fraction (forecut). A gas chromatography, mass spectroscopy (K+IDS) and lH
10 NMR analysis indicated the products having the desired disilane structure with >
97 % purity composed of four isomers in ratio 7/113/1 (measured by GC). The monomer obtained, namely 5-(2-trimethoxysilylethyl)-trimethoxysilylnorbornane, (280 g) was a colorless liquid having a viscosity of < 0.1 poise at room temperature.
Oli~omer of ExamPle 3 In a five-liter flask equipped with a magnetic stirrer, Vigreux 287300 fractional distillation head, supplied by Kontes under a nitrogen blanket, a reaction mixture of hydrogenated bisphenol A HBPA (700g, 2.91 mole), difunctional silane monomer 1 of Example 1 above-(2400 g, 6.82 mole of 1 4-VCH-Si2), 20 Nafion'9 NR-50 (100 g) catalyst supplied by DuPont Company of Wilmington, Delaware and trifluoroacetic acid (TFAA, Sg) was heated at 100-120~C. After about 6 hours, the pot temperature was increased from 105 to 119~C and about 240 ml MeOH was collected as a byproduct. The resulting crude reaction product had a viscosity of 12 poise, color a=-1.3, b=+6.4 (as measured by Minolta 25 Colorimeter). The crude product was diluted with about 500 ml hexanes, filtered through a multilayer system composed of: a Whatman 50 filter paper supplied by VWR Scientific Products of Philadelphia, Pennsylvania: silica gel desiccant, grade 12 (EM-SX0143J-3); silica gel 60 (EM#9385-3) supplied by VWR Scientific Products; decolorizing carbon supplied by VWR Scientific Products, Norit 211 30 (EK-1133099) supplied by VWR Scientific Products. Volatiles were removed in 1 hour at 75~C under vacuum (20 Torr) on a rotary-evaporator supplied by VWR
Scientific Products. The resulting reactive silane oligomer obtained by reactingthe diol with the difunctional silane monomer and water had a yield of 2700 g, viscosity of 15 poise, Mn = 1750, Mw/Mn = 1.45 (as det~".~hled by Matrix 35 Assisted Laser Desorption Ion Mass Spectroscopy (MALDI MS), color of a=-0.79, b=+ 3.8 (as determined by Minolta Colorimeter).
The following is a representative reaction mech~ni~m, based on the foregoing Example 3 for specific oligomerization providing a narrow CA 022~3098 1998-11-09 polydispersity oligomer mixture enriched in low oligomers and particularly the desired reactive silane trimer, which was a 4-(2-trimethoxysilylethyl)- 1-trimethoxysilylcyclohexane/hydrogenated bisphenol A (hereafter-VCH-Si2/HBPA/VCH-Si2):
Scheme 1. Hybrid silane reactive oligomers in the VCH-SiJHBPA/H20 system.
HO~' + (MeO)3Si~Si(OMe)3 + H20 HBPA VCH-Si2 OMe OMe OMe OM~
XQ~,OSi~S,I-- Y + Ml OSi~Si-- OMe - OMe n - OMe ll where, X y la: ( MeO)3Si-VCH-(MeO)2Si- OMe Ib: (MeO)3Si-VCH-(MeO)2Si-O-Si(OMe)2-VCH-(MeO)2Si- OMe Ic: (MeO)3Si-VCH-(MeO)2Si-O-Si(OMe)2-VCH-(MeO)2Si- O-Si(OMe)2-VCH-Si(OMe)3 Id: H OMe n = 1 , 2, 3...
MALDI and LDI MS analysis revealed that the reactive silane oligomers were composed of 5 homologue series with several major components (22%) of molecular weights in the 350-3000 range (Example 3, Table 1). Data indicated that the final products were combinations of two VCH-Si2 silane oligomers, i.e.,by silication of HBPA and by hydrolysis/condensation with adventitious H2O
shown in Scheme 1.
Although MALDI discrimin~tes against low molecular mass components, combined with GC, it gave a good approximation of the oligomeric composition.
The reactive hybrid oligomers contain 13 major components (22 wt %) (Example 3, Table 1), which represented 5 homologue series (Scheme 1). There are three oligomer classes, i.e., unreacted VCH-Si2 (~25 wt %), HBPA/VCH-Si2 oligomers (~Ia+Id ~ 50 wt %) and H2O/VCH-Si2 oligomers ( +Ic+II(n>~) ~ 25 wt %).
20 The oligomerization process was not complete, because ~6% hydroxyl groups of HBPA remained unsilylated in the Id oligomers. At higher conversions, oligomer viscosity drastically increased, which is detrimental for coating reproducibility and VOC. There are three types of reactive bonds to the silicon, which determine thereactivity/stability balance of the hybrid oligomers, i.e., original Si-OCH3 (88.5 25 mol %), Si-OC(cyclohexyl in HBPA) (9.3 mol %) and Si-OSi (2.2 mol %) from adventitious H2O, which were in the 1/0.11/0.025 molar ratio, respectively. The CA 022~3098 1998-11-09 oligomers had a narrow polydispersity (Mw/Mn < 1.5 by MALDI at Mn = 1800), which is critical for high solidsAow viscosity balance and good compatibility with other coating composition components. The key to achieving the narrow Mw/Mn is a selective oligomerization pattern due to the asymmetrical VCH-Si2 structure, 5 which had two trimethoxysilyl groups of different reactivities. The silicon group attached to the primary carbon atom (Cp)was significantly more reactive than thesilyl group connected to the secondary carbon atom (Cs) of the cyclohexane ring.Table 1 shows the major col,lponents (--2%) of the silane reactive oligomers in the VCH-Si2/HBPA/H2O system, as detellllined by MALDI MS
10 (Scheme 1) of example 3.
Example 3 of Table 1.
Oligomer II Id II Ia II Id Ib Ia Ic Ib Ia Ib Ia DP(n) 1 1 2 1 3 2 1 2 1 2 3 3 4 M.W. 352 560 658 880 9641088 11861408 14921714 19362242 2464 (wt %) 233 2.7 9.5 28 3.4 2.4 4.8 11 2.1 3.6 5.5 1.9 2.5 (mol %)46 3.4 10 22 2.5 1.6 2.8 5.5 1.0 1.5 2.0 0.6 0.7 SiOCH3b27.41.7 0.122.3 3.4 1.4 3.9 7.6 1.8 2.6 3.5 1.2 1.5 SiOCHBPA 0 0.3 0 4.5 0 0.3 0.6 1.6 0.2 0.4 0.8 0.2 0.3 SiOSi 0 0 1.0 0 0.5 0 0.3 0 0.2 0.1 0 0.1 0 a) by GC
b) SiOCH3 (mol %) = 100%xSiOCH3/3x ~Si (mol/mol) 15 SiOCHBPA (mol %) = 100%xSiOCHBPA/3x~;Si (mol/mol) SiOSi (mol %) = 100%xSiOSi/3x~Si (mol/mol) c) Dp (n) degree of polymerization Oli~omers of ExamPles 4-16 The procedure described earlier in Example 3 was followed in plepaling 20 the oligomers of Examples 4-16 shown in Table 2 below, where Component I (as in Scheme 1, shown above) is 4-VCH-Si2/HBPA.
. .
CA 022~3098 1998-11-09 Table 2 Ex. A Ba ca D E Fb Gc HC I J Kd 4 1.17 3.1 0.19 119 ,6 22 73 22 1.8 s 1.17 3.1 o.ls 120 5 86 120 7 89 66 0.8714 3.9 1.2f 6 1.17 3.1 o.l9 120 3 82 120 s 86 64 0.8712 2.7 0.7f 7 1.20 0.77 0.77 120 5 87 5.6 6.s 120 8 89 6s 0.887.0 7.6 1.8 8 1.20 0.77 120 s 84 6.2 7.s 120 8 89 61 0.827.0 10.1 1.6 9 1.20 0.15 142 2 82 4.9 3.1 42 s 87 60 0.837.3 6.6 0.8 o 1.20 0.15 135 s 87 s.o 2.1 +o.ls136 9 so 60 0.807.6 2.7 O.Se P-Hf 0.78 o.so o.10 140 2 78 80 0.8083 2.9 0.3 2 o.so o.so 0.10 120 5 66 18 8 73 75 o.s 30 2.6 0.8 3 l.lo 3.8 0.15 120 5 87 15 4.7 8 so 82 o.ss19 5.5 2.7 4 1.15 3.8 0.15 120 5 87 lo 6.9 8 so 75 0.9615 8.9 3.7 1.20 3.8 0.15 120 5 89 8.0 5.8 8 92 72 0.9412 8.0 3.
6 1.25 3.8 0.15 120 5 86 5.4 6.6 120 8 89 73 1.037.8 8.s 3.
Ex. means Examples A Molar ratio of disilane to hydroxyls of diol monomers B Catalyst 5 C Catalyst co-component (TFA) D Reaction temperature in degrees Centigrade E Reaction time in hours F byproduct in weight percentage formed during oligomerization G VCH weight percentage conversion 10 H VCH/OH conversion ratio oligomer viscosity in poise J (b) color reading of crude oligomer CA 022~3098 1998-11-09 K (b) color reading of filtered oligomer a Nafion(~) NR-50 catalyst; TFA = CF3CO2H both supplied by DuPont Company of Wilmington, Delaware b MeOH yield (%) = MeOH collected/2XHBPA (mole/mole) X 100%
5 c VCH conversion (%) by GC; VC/OH = VCH conversion/MeOH yield (mole/mole) d color value after filtration through carbon/celite/silica/f1lter paper e color value after filtration through celite/silica/filter paper only f color value with Decolorizer added (P-H = 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide) The forgoing Table 2 illustrates that the oligomer composition and properties, such as optical clarity can be varied widely by varying the molar ratio and the extent of the oligomerization as controlled by the catalyst choice, reaction time and temperature.
The procedure described earlier in Example 3 was followed in p~cp~illg ; the oligomers of Examples 17-20 shown in Table 3 below, where Component I (as in Scheme 1, shown above) is 4-VCH-Si2/HBPA.
Table 3 Ex. A Ba C D E Fb Gc H I Jd 171.20 0.26 105 5 68 4.8 1.3f (Me) 110 7 71 5.2 l.lf 140 9 75 590.94 6.3 1.4f 0.5 181.20 0.30 107 5 79 5.1 1.2f (Me) 145 8 85 530.75 5.6 l.1f o.5e /MS
191.20 0.19 106 5 74 6.0 1.3f (Bu) 135 7 81 580.86 8.1 2.5f 0.10 201.20 0.19 110 5 79 5.3 1.0 (Bu)/ 110 7 80 0.9 MS 138 8.5 84 610.87 7.3 1.2 0.02 Ex. means Examples 20 A Molar ratio of disilane to hydroxyls of diol monomers B Catalyst C Reaction tt;lllpeld~ul~ in degrees Centigrade D Reaction time in hours E byproduct in weight percentage formed during oligom~ri7~tion 25 F VCH weight percentage conversion G VCH/OH conversion ratio H oligomer viscosity in poise (b) color reading of crude oligomer J (b) color reading of filtered oligomer 30 a R4NOH, where R = Me,Bu MS = purified over molecular sieves CA 022~3098 1998-11-09 b MeOH yield (%) = MeOH collected/2X HBPA (mole/mole) X 100%
c VCH conversion (%) by GC
VC/OH = VCH conversion/MeOH yield (mole/mole) d color value after filtration through carbon/celite/silica/filter paper S e color value after filtration through celite/silica/filter paper only f hazy From the forgoing data, it is seen that the reactive silane oligomers of the present invention having low polydispersity are produced when the control of themolar ratios between the difunctional silane monomers, water and the diol 10 monomers as well as the reactivity ratio of disilane to hydroxyls (Cp/Cs) in the claimed ranges is ~l~ili7ed Furthermore, higher the molar ratio, lower will be the viscosity. By including such oligomers in a coating composition, its viscosity is reduced and its miscibility is improved.
Oli~omer of ExamPle 21 A mixture of bis(trimethoxysilyl)-limonene (470 g, 1.24 mole), water (16 g, 0.89 mole) and dodecylbenzenesulfonic acid amine salt (5.0 g) was reacted for12 hours at room telllpe.alu.~ Volatiles (57.6 g) were removed under vacuum.
The cloudy reaction product was diluted with 500 ml of anhydrous hexanes and filtered through dry silica gel 60 and dry decolorizing activated carbon under nitrogen. Volatiles were removed under vacuum. The filtered reaction product was a colorless liquid having viscosity of 6.4 poise, containing c 7 % starting monomer, as measured by GC, a dimer as a major component and a small amount of trimer, as measured by KIDS mass spectroscopy. The reactive silane oligomers obtained by reacting disilylated limonene with water showed significantly enhanced solids residue at 93.6 % vs. that of the starting monomers, when small samples were heated for I hour at 100~C (220~F). Additional reactive silane oligomers were also made by using the foregoing process where the viscosities were measured at 1.0, 1.4, 3.2, 5.2, 6.1, 14, 15 and 16 in poises.
Oli~omer of ExamPle 22 A mixture of 5-(2-trimethoxysilylethyl)-trimethoxysilylnorbornane (290 g, 0.80 mole), water (9.0 g, 0.50 mole) and dodecylbenzenesulfonic acid amine salt (3.0 g) was reacted for 12 hours at room te-~ lul~;. Volatile were removed under vacuum. The cloudy reaction product was diluted with 300 ml of anhydrous hexanes and filtered through dry silica gel 60 and dry decolorizing activated carbon under nitrogen. Volatiles were removed under vacuum. A yield of 170 g the filtered reaction product was obtained. It was a colorless liquid having a viscosity of 1.6 poise, containing < 15 % of starting monomers, as measured by GC, a dimer as a major component and a small amount of trimer, as measured by KIDS mass spectroscopy. The reactive silane oligomers obtained by reacting 5-(2-trimethoxysilylethyl)-trimethoxysilylnorbornane with water showed CA 022~3098 1998-11-09 ~ significantly enhanced solids residue vs. that of the starting monomers, when small samples were heated for 1 hour at 100~C (220~F). Additional reactive silane oligomers were also made by using the foregoing process where the viscosities were measured at 1.2 and 1.5 in poises.
S OliYomer of ExamPle 22 To a two-liter, three-neck flask, equipped with a magnetic stirrer, reflux condenser, addition funnel under nitrogen blanket, a reaction mixture of 2-trimethoxysilylethyl-trimethoxysilylcyclohexane (930 g, 2.66 mole) and dodecylbenzenesulfonic acid aminoplul)allol salt (10 g) was added. With stirring, the contents of the flask were heated at 70~C and water (32 g, 2.0 mole) was added dropwise at the rate 4 g/10 min. After the addition of 16 g water, the reaction mix became cloudy. Nafion~ NRS0 (3.7 g) catalyst was added and then the remaining 16 g water was added over the 10 minutes. The reaction was continued at 70~C for another 12 hours. Volatiles (157 g) were removed at 80~C
under vacuum. The cloudy reaction product was diluted with 400 ml anhydrous hexanes and filtered through dry silica gel 60 (EM Science # 9385-3) and dry charcoal (activated Darco G-60, EM Science # CX0645-1). Volatiles were removed under vacuum. A yield of 483 g of almost colorless filtered reaction product was obtained. It was a liquid having a viscosity of 4.3 poise cont~ining 4 % starting disilane, as measured by GC. The reactive silane oligomers obtained by reacting 2-trimethoxysilylethyl-trimethoxysilylcyclohexane with water showed significantly enhanced solids residue vs. that of the starting monomers, when small samples were heated for 1 hour at 100 ~C (220~F). Additional reactive silane oligomers were also made by using the foregoing process where the viscosities were measured at were 0.6, 0.8, 1.2, 1.6, 2.1 and 3.2 in poises
PROCESS FOR PRODUCING
REACTIVE SILANE OLIGOMERS
Ba~k~round Of The Invention This invention concerns a composition comprising reactive silane oligomers having low polydispers ty, viscosity and volatility. Such oligomers are useful for multi-component silicon modified organic co~tings with low volatile organic content (VOC), improved mar and etch resistance.
A number of clear and pigmented coating coll.posilions are utilized in various coatings, such as, for example, automotive coatings. Such coatings, typically applied as OEM coatings (original e~ l manufacturer), are generally solvent based. However, due to increasing conccl~l over the excessive release of volatile organic co.llponent (VOC) in the atmosphere, significant research is being conducted for developing low VOC, solvent-based coating compositions, generally with less than 0.6 kilograms of organic solvent per liter of coating composition (5 pounds per gallon), as determined under ASTM D3960 Test.
One of the approaches used in reducing the amount of VOC released by a coating composition during its application on a substrate, such as an automobilebody, involves adding a silicon-containing reactive diluent to the coating composition. A number of patents disclose low VOC silicon-containing curable coating compositions, such as, for example, U.S. Patent 4,467,081.
However, none of the approaches disclosed in the prior art improves miscibility in multi-component formulations while still m~int~ining OptilllUIll balance of coating p~ope- lies, such as good mar and chemical resistance, high gloss and durability. Further limiting factor in the use of silane-based reactive diluents in coating compositions is the poor process control of silane functionalities during the ~lcpal~lion of conventional reactive ~ ent.~, which results in a broad distribution of silane functionalities.
The present invention ovelcolnes the foregoing problems, by providing low VOC silane-based coating compositions that result in coqtings having improved mar, chemical and envh~onl--ental etch re~i~t~ e, a~pea.a,lcc and durability while still providing improved miscibility in multi-cGmponent formulations, as compared to conventional coating co.-.l)osilions.
Statement Of In-~ention The present invention is directed to a process for making a reactive silane oligomer, said process comprising:
CA 022~3098 1998-11-09 ~ contacting one or more unsymmetrical difunctional silane monomers with water, with one or more diol monomers, or with a combination thereof, wherein:
said diol monomer is:
Rl -(OH)z, wherein Rl is selected from the group consisting of:
a) C2 to C20 alkylene, cycloaliphatic ringS or aromatic rings, each optionally substituted with at least one member selected from the group consisting of O,N,PandS;
b) two or more cycloaliphatic or aromatic rings connected to each other through a covalent bond, or through an alkylene group of 1 to 5 carbon atoms, orthrough a heteroatom, or fused together to share two or more carbon atoms, each optionally substituted with at least one member selected from the group consisting of O, N, P and S; and c) a linear polyester, branched polyester, a combination of said linear and said branched polyesters, polyacrylate, polyolefin, polyether, polycarbonate, polyurethane, or polyamide, each having a GPC weight average molecular weight in the range of from about 200 and 10,000; and said difunctional silane monomer is:
H H
XPYP25i--Cp--R2_Cs--SiYs2Xs wherein Cp is a primary carbon atom, Cs is a secondary carbon atom and R2 is selected from the group consisting of:
a) C3 to C20 alkylene, C~ to C~0 alkyl substituted cycloaliphatic rings or C~ to Cl0 alkyl substituted aromatic rings, each optionally substituted with at least one member selected from the group consisting of O, N, P and S;
b) Cl to Clo alkyl substituted two or more cycloaliphatic rings, or Cl to C1o alkyl substituted two or more aromatic rings conn~cte~l to each other through a covalent bond, or through an alkylene group of 1 to 5 carbon atoms, or through aheteroatom, or fused together to share two or more carbon atoms, each optionallysubstituted with at least one member selected from the group con~icting of O, N, P
and S; and c) a combination of (a) and (b);
R3, R4 and Rs each is independently selected from the group consisting of:
Hydrogen, C~ to C20 alkyl, C~ to C~0 alkyl substituted cycloaliphatic rings or C, to C,0 alkyl substituted aromatic rings, each optionally substituted with at least one member selected from the group consisting of O, N, P and S;
CA 022~3098 1998-11-09 XP and Xs being independently selected from the group consisting of alkoxy containing I to 20 carbon atoms, acyloxy containing 1 to 20 carbon atoms,- phenoxy, halogen, amine, amide, urea, imidazole, carbamate, ketoximine, oxazolidinone, and a combination thereof; and YP and Ys being independently selected from the group consisting of alkyl containing 1 to 12 carbon atoms, alkoxy containing 1 to 20 ~arbon atoms, acyloxycontaining I to 20 carbon atoms, phenoxy, halogen, amine, amide, urea, imidazole, carbamate, oxazolidinone, and a combination thereof;
for producing said reactive silane oligomer having a GPC weight average molecular weight of less than 10,000 and having a polydispersity of less than 3.The present invention is also directed to a reactive silane oligomer of the forrnula:
XsY 52Si _~5--R2 _(;p--SiYP2 --O--Rl--O--SiYP2 --~p--R2--l~s--SlYs2Xs Rs_~--R3 H H R --~--R
when the unsymmetrical difunctional silane monomer is contacted with the diol monomer in the foregoing process.
The present invention is also directed to a reactive silane oligomer of the formula:
XsYS2Si--Cs--R2_Cp--SiYP2 0--SiYP2--Cp--R2_Cs--SiYs2Xs when the unsymmetrical difunctional silane monomer is contacted with water in the foregoing process.
The present invention is further directed to a coating colllposilion containing the reactive silane polymer made in ac~ ce with the foregoing process.
The present invention advantageously provides for a low VOC coating composition having high solids content.
The process of the present invention optimally and efficiently converts the re~t~ntc into a reactive silane oligomer having lower polydi~ ily, viscosity andvolatility than a conventional silane oligomer.
The process of the present invention further advantageously produces a re~tive silane oligomer having a low GPC weight average molecular weight of less than 10,000. Such a reactive silane oligomer, when included as a reactive diluent in a coating composition, lowers VOC while .cimlllt~nçously in~ ,asing the CA 022~3098 1998-11-09 solids content of the composition. As a result, users can efficiently apply suchcoating compositions by conventional means, such, as by spraying, dipping, roller coating, brushing or by electro-coating, and still produce durable coatings withlow mar, etch and chemical resistance, and glossy appearance on conventional 5 substrates, such automotive bodies.
Detailed Description of the Invention As used herein:
"High solids composition" is a coating composition having more than 40 weight percent, preferably in the range of from 60 to 100 weight percent of total 10 solids based on the total weight of the composition.
"Low VOC composition" is a coating composition having less than 0.6 kilograms of solvent per liter of the coating composition.
"Low viscosity composition" is a coating composition having viscosity in the range of from I to 10,000 centipose as measured under ICI cone and plate 1 5 viscometer.
"GPC weight average molecular weight" means weight average molecular weight as determined by gel permeation chromatography (GPC) using polystyrene standard.
"Polydispersity" means GPC weight average molecular weight divided by 20 GPC number average molecular weight.
"Reactivity" means a degree of chemical activity of silane groups attached to carbon atoms in the backbone of a silane monomer.
"Primary carbon atom (Cp)" is a carbon atom in the backbone, shown below, of an unsymmetrical difunctional silane monomer having only one carbon 25 atom attached to it.
IH
I P
H
"Secondary carbon atom (Cs)" is a carbon atom in the backbone of the unsymmetrical difunctional silane monomer, shown below, having one hydrogen atom and two carbon atoms attached to it.
CA 022~3098 1998-11-09 I S--I
-f It is believed, without reliance thereon, that the presence of two carbon attached to Cs, due to steric factors, makes the silane groups attached to Cs chemically less reactive than the silane groups attached to Cp. The presence of Cp S and Cs, preferably provided with the same silane groups (SiY2X), produces the asymmetric reactivity in the unsymmetrical difunctional silane monomer.
This invention is directed to a process for making reactive silane oligomers having low polydispersity of less than 3. Inclusion such reactive silane oligomers in a coating composition results in a low VOC coating composition having low 10 viscosity and high solids. The process utilizes unsymmetrical difunctional silane monomers preferably provided with two structurally identical silane reactive groups attached to Cs and Cp for inducing significantly different reactivities, mostly resulting from the steric factors. The process of the invention results in a low dispersity reactive silane oligomer having low GPC weight average molecular weight in the range of 200 to 10,000, preferably in the range of from 400 to 5000, and more preferably in the range of from 500 to 2000. The polydispersity of the reactive silane oligomer is in the range of from 1.1 to 3, preferably in the range of from I.1 to 1.8, and more preferably in the range of from 1.1 to 1.5.
The process of the invention includes contacting one or more unsymmetrical difunctional silane monomers with one or more diol monomers or with water, or with a combination thereof, to produce the reactive silane oligomer.
The preferred reactive silane oligomers are dimers resulting from the reaction of disilane monomers with water and trimers resulting from the reaction of a disilane monomers with diol monomers.
The diol monomer suitable for use in the present invention is typically provided with a hydroxyl equivalent weight in the range of from 30 to 2500, preferably in the range of from 50 to 500 and has the following formula:
Rl-(OH)2 (I) Rl group in foregoing formula I may include:
(a) C2 to C20 alkylene; aromatic or preferably cyclo~liph~tic rings.
Some of the suitable C2 to C20 alkylene include ethylene, propylene, butylene, pentylene and hexylene groups.
Some of the suitable cycloaliphatic ring groups include cyclopentylene, cyclohexylene, terpinylene. Cyclohexylene is preferred.
.
CA 022~3098 1998-11-09 - Some of the suitable aromatic ring groups include phenylene, naphtylene, anthracylene.
Each member in the foregoing (a) group may optionally be substituted with at least one member selected from the group consisting of O, N, P and S, N and O5 are preferred, O is more preferred.
Some examples of the simple diols include 2,3-dimethyl-2,3-butanediol(pinacol), 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2-ethyl-2-methyl-1,3-propanediol, 2,5-dimethyl-2,5-hexanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, l,10-dec~rle-liol, 10 1,12-dodecanediol, and cycloaliphatic diols such as 1,4-cyclohe~ e-~im~.thanol, 4,4'-isopropylidenedicyclohexanol, 4,8-bis(hydroxymethyl)tricyclodecane.
Neopentyl glycol and cycloaliphatic diols, such as 4,4'-isopropylidenedicyclohexanol are preferred.
R' may also include:
(b) 2 to S, preferably 2 to 3, cycloaliphatic rings or aromatic rings connected to each other through a covalent bond, or through an alkylene group ofI to 5 carbon atoms, or through a heteroatom, or fused together to share in the range of from 2 to 8 carbon atoms. The cycloaliphatic rings or aromatic rings connected to each other through the alkylene group or the covalent bond are 20 preferred, those connected through the alkylene group are more preferred. Thecycloaliphatic rings or aromatic rings suitable for the foregoing group are the same as those described earlier.
Each member in the foregoing (b) group may optionally be substituted with at least one member selected from the group consisting of O, N, P and S. O
25 and N are preferred, O is more preferred.
Rl may also include:
(c) a linear polyester, branched polyester, a combination of the linear and the branched polyesters, polyacrylate, polyolefin, polyether, polycarbonate, polyurethane, or polyamide group, each having a GPC weight average molecular 30 weight in the range of from about 300 and 10,000, preferably in the range of from 300 to 4000, more preferably in the range of from 300 to 3000.
Linear polyester diols are generally known and are prepared by conventional methods using simple diols known in the art, including but not limited to the previously described simple diols and dicarboxylic acids. Examples 35 of suitable dicarboxylic acids include but are not limited to: hexahydro-4-methylphtalic acid; hexahydrophtalic acid; phtalic acid; isophtalic acid;
terephtalic acid; adipic acid; azelaic acid; sebasic acid; succinic acid; maleic acid;
glutaric acid; malonic acid; pimelic acid; suberic acid; fumaric acid; and itaconic CA 022~3098 1998-11-09 acid. Anhydrides of the above acids, where they exist, can be also employed and are encompassed by the term "dicarboxylic acids".
In addition, multifunctional monomers which contain both hydroxyl and carboxyl functionalities, or their derivatives are also useful. Such monomers 5 include but are not limited to:
Lactones, such as, caprolactone, butyrolactone, valerolactone, propiolactone; and hydroxyacids, such as, 2-hydroxyc~,oic acid.
Polyester diols are preferably prepared by first reacting simple diols known in the art, including but not limited to the previously described simple diols, with 10 diacid anhydrides known in the art, including but not limited to the previously described anhydrides. One of the preferred polyester diol is prepared by reacting hexahydromethylphtalic anhydride with water to provide a co,~ onding dicarboxylic acid. Such a dicarboxylic acid when reacted with an alkylene oxide,preferably with the glycidyl esters of organic acids, such as, for example, 15 CARDURA-E~ glycidyl ester, supplied by Shell Chemical Company, Houston, Texas, results in a preferred polyester diol.
Polyether diols are generally known and are plc~a~ed by conventional methods, typically by the ring opening polymerization of cyclic ethers, acteals, or a combination thereof. Cyclic ethers are known in the art, such as, for example,20 epoxides (having a 3 member ring), oxetanes (having a 4 member ring), furanes(having a 5 member ring) and higher cyclic ethers having in the range of from 6 to 10 member rings. Ethylene and propylene oxide and tetrahydlorul~le are preferred, tetrahydrofurane is more preferred. Optionally, simple diols, such as, those described previously, may be used for introducing the hydroxyl end groups 25 and for controlling the molecular weight of the polyether diols. Examples of useful polyether polyols include the generally known poly(tell~lethylene oxide) diols, available commercially as TERATHANE0 poly(tetla~llethylene oxide) diol, supplied by DuPont Company of Wilmington, Delaware. TERATHANE~
poly(tetramethylene oxide) diol is prepared by polymerizing tetrahydrofurane in 30 the presence of cationic catalysts. Other useful polyether diols also include the poly(propylene oxide) diols prepared by cationic or anionic polymerization or copolymerization of propylene oxide. The simple diols known in the art, including but not limited to the previously described simple diols may be used as initiators or telogens to provide controlled linear structures to the r~-snlting35 polyether diols.
Linear amide-cont:~ining diols are generally known and are typically prepared by analogous processes described previously in the plt;l)~a~ion of the polyester diols from any of the aforedescribed diacids, diols or lactones.
CA 022=,3098 1998-11-09 Additional amounts, in the range of from 10 to 80, preferably in the range of from 20 to 70, all in weight percentages based on the total weight of monomer mixture, of diamines, aminoacids, lactams, or aminoalcohols or a combination thereof are also typically utilized.
Polycarbonate diols are generally known and are prepared conventionally by reacting previously described simple diols with carbonates. Aliphatic polycarbonate diols may also be prepared from 1,3-dioxan-2-one or derivatives thereof. Current conventional methods for the pl.,palalion of the aliphatic polycarbonate diols include tr~n~estçrification of simple diols with lower 10 carbonates of dialkyl preferably having in the range of from 1 to 4 carbon atoms;
dioxolanones; or diphenyl carbonates, in the presence of conventional catalysts,such as alkali metal, tin, and titanium compounds.
Polyurethane diols are generally known and are prepared conventionally by reacting previously described simple diols, polyester diols, amide-containing 15 diols, polycarbonate diols, polyhydrocarbon diols with organic polyisocyanates.
The organic polyisocyanate can be reacted with the diol either directly to form the polyurethane diol or by the generally known prepolymer method wherein the diol and polyisocyanate are reacted in relative plopollion to first produce an isocyanate terminated prepolymer with subsequent reaction of the prepolymer with the same 20 or different additional diol to form the polyurethane diol. The polyisocyanate which is reacted with the diol may be any organic polyisocyanate such as, for example, aromatic, aliphatic, cycloaliphatic, or heterocyclic polyisocyanate, which may be unsubstituted or substituted with alkyl groups, preferably having 1 to 4 carbon atoms. Many such organic polyisocyanates are generally known, examples 25 of which include: toluene diisocyanate isomers, diphenylmethane diisocyanate isomers, biphenyl diisocyanate, tetramethylene-1,4-diisocyanate, hexamethylene-1,6-diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate isomers, hexahydrotoluene diisocyanate isomers and mixtures thereof.
Polyhydrocarbon diols are generally known and are prepared 30 conventionally by polymerizing simple olefins, such as isoprene, butadiene and styrene usually, in the presence of difunctional anionic initiators, followed byhydroxylation with epoxides. Alternatively, such simple olefins may be polymerized in the presence of multifunctional cationic initiators for monomers,such as isobutylene or styrene, followed by hydroxylation of olefin t~nnin~l 35 groups. Polyhydrocarbon diols are generally known and available commercially, as KRATON LIQUI~ polyhydrocarbon diol, supplied by Shell Chemical Company, Houston, Texas.
CA 022~3098 1998-11-09 Most preferred diol monomers include 1,4 cyclohexane dimethanol, hydrogenated bisphenol A, or a combination thereof.
The unsymmetrical difunctional silane monomers suitable for use in the present invention has a weight average molecular weight in the range of from 300S to lS00, preferably in the range of from 350 to 1000. It is of the following formula:
IH IH
XY2Si--Cp--R2_Cs--SiY2X
R (II) In formula II, Cp is a primary carbon atom and Cs is a secondary carbon atom. R2 in formula II is selected from one or more of following:
a) C3 to C20 alkylene, C~ to C~o alkyl substituted cycloaliphatic rings or Cl to C~0 alkyl substituted aromatic rings, Each member in the foregoing (a) group may optionally be substituted with at least one member selected from the group consisting of O, N, P and S. O and Nare preferred, O is more preferred.
b) C~ to Clo alkyl substituted two or more cycloaliphatic rings, or Cl to C10 alkyl substituted two or more aromatic rings connected to each other through a covalent bond, or through an alkylene group of 1 to 5 carbon atoms, or through aheteroatom, or fused together to share two or more carbon atoms, Each member in the foregoing (b) group may optionally be substituted with at least one member selected from the group consisting of O, N, P and S. O
and N are preferred, O is more preferred; and c) a combination of (a) and (b).
Preferred (a) in the foregoing R2 are cyclohexylene and terpinylene, more preferred being cyclohexylene.
Preferred (b) in the foregoing R2 is norbornylene.
R3, R4 and R5 each is independently selected from the group consisting of:
Hydrogen, Cl to C20 alkyl, Cl to C~0 alkyl substituted cycloaliphatic rings or Cl to C~0 alkyl substituted aromatic rings, each optionally substituted with at least one member selected from the group consisting of O, N, P and S, O and N
30 are preferred and O is more preferred.
XP and Xs each in formula II is independently selected from the group consisting of alkoxy containing 1 to 20 carbon atoms, acyloxy cont~ining 1 to 20 carbon atoms, phenoxy, halogen, amine, amide, urea, imidazole, carbamate, ketoximine, imidazole, oxazolidinone, and a combination thereof.
CA 022~3098 1998-11-09 YP and Ys each in formula II is independently selected from the group consisting of alkyl containing 1 to 12 carbon atoms, alkoxy containing 1 to 20 carbon atoms, acyloxy containing 1 to 20 carbon atoms, phenoxy, halogen, amine, amide, urea, imidazole, carbamate, ketoximine, oxazolidinone, and a combination S thereof. Alkoxy is preferred and methoxy is more preferred.
Examples of the preferred unsymmetrical difunctional silane monomers include but are not limited to bis(trimethoxysilyl) derivatives of the followingpolyolefins: limonene and other terpines, 4-vinyl-1-cyclohexene, S-vinyl-2-norbornene. The preferred unsymmetrical difunctional silane monomers include 10 4-(2-trimethyoxysilylethyl)-1-trimethoxysilylcyclohexane, S-(2-trimethoxysilylethyl)-trimethoxysilyl norbornane, or a combination thereof.
When the diol monomers are contacted with the unsymmetrical difunctional silane monomers in accordance with the process of the present invention, resulting reactive silane oligomers usually contain variable levels, 15 generally in the range of from I to lO0 weight percent, preferably in the range of from 3 to 80 weight percent based on the total weight of monomer mixture of their corresponding hydrolysis and condensation products from the reaction with water,which may be added purposely or may be adventitiously introduced from the ambient moisture or with other components, particularly with the diol monomers 20 whose commercial grades usually contain significant levels of water. As a result of the aforedescribed hydrolysis/condensation processes more stable -Si-O-Si-linkages are advantageously introduced in the resulting reactive silane oligomeralong with an increase in weight average molecular weight, and a relative reduction in viscosity compared over convention reactive silane oligomers 25 prepared from symmetrical disilane monomers The oligomerization of the diol monomers with the difunctional silane monomers resulting in the C-O-Si formation is an equilibrium process. As a result, the output of the process can be controlled to achieve higher yield of the desired Rl-C-O-Si-R2 by using a stoichiometric excess of the difunctional silane30 monomers, removing a volatile X-H byproduct from the reaction mixture, or by utilizing both of the foregoing steps.
The silylation/oligomerization of the diol with disilane mol~ol"el~ usually results in a complex mixture composed of various oligomers and isomers, shown by mass spectrographic analysis. This is due to the random nature of the silylation 35 involving multifunctional reactants and a contribution of the silane hydrolysis/condensation processes, usually due to the adventitious formation of water. An attractive coating plop~l~y balance invention, such as scratch, chemical etch resistance and appearance, of a coating composition containing the reactive CA 022~3098 1998-11-09 silane oligomer of the present invention is often obtained by a narrow operational window of a specific product mixture composition. The oligomer composition can be varied widely by the molar ratio of the reactants and the extent of the oligomerization controlled by the catalyst choice, reaction time and reaction 5 temperature.
Thus, the process of the present invention may be further improved by any one or a combination of the following steps for producing the reactive silane oligomers:
I. By adjusting the reactivity ratio (CptCs) between the silane groups (XY2Si-) attached to Cp and Cs in the range of from 1.1 to 100,000, preferably in the range of 1.1 to 10,000, more preferably in the range of from 2 to 1000. It was unexpectedly discovered that by utilizing the difference between the higher reactivity of the silane group attached to the Cp and the lower reactivity of the identical silane group attached to the Cs, the reactive silane oligomers of the present invention are produced. The reactivity ratio may be further increased bysubstituting one or more hydrogen atoms on carbon atoms connected to Cs with moieties selected from the group consisting of Cl to C20 alkyl or aryl groups, or a combination thereof. Cl to C20 alkyl groups are plc;felled.
II. By adjusting the molar ratio of disilane to hydroxy groups in the range from 0.7 to 4, preferably in the range of from 0.7 to 3, more preferably in the range of from 0.9 to 1.4 between:
i) the difunctional silane monomers and 2 times water, ii) the difunctional silane monomers and 2 times the diol monomers, or iii) difur~tional silane Ill~)l~lllelD
2 (water and diol Illo~ D) III. By increasing the conversion of the unsymmetrical difunctional silane monomers into the reactive silane oligomer in the range of from 50 percent to 100 percent, preferably in the range of from 60 percent to 95 percent, more preferably in the range of from 65 percent to 90 percent. The foregoing increase in the conversion is accomplished by increasing the catalyst reactivity and concentration, increasing the reaction tel,lpe,~tule during the oligomerization, and increasing the reaction time.
IV) By utili7ing a combination of said steps I, II, and m.
The reaction may be carried out with or without a catalyzing amount of a catalyst, primarily depending on the reactivity of the SiX. The catalyzing amount of the catalyst used is typically in the range of from 0.01 percent to 5 percent, preferably in the range of from 0.01 percent to 2 percent and more preferably inthe range of from 0.01 percent to 0.5 percent, all in weight percentages based on ll CA 022~3098 1998-11-09 the total weight of starting reaction mixture. It is desired for the storage stability, particularly moisture stability to prepare the reactive silane oligomer essentially free of a catalyst. Therefore, catalysts which can be effectively and conveniently removed from the products, by conventionally means, such as ion exchange or S absorbing media, are preferred. Particularly useful catalysts include heterogeneo~s catalysts, such as, fluoroalkylsulfonic acid NAFION~9 NR-50 supplied by DuPont Company of Wilmington, Delaware, which can be easily separated from the product. Other preferred catalysts are volatile catalysts, such as, trifluoroacetic acid; amines or thermofugitive catalysts, such as, 10 tetraalkylammonium hydroxides, which can be substantially removed by a post-heating. Many other useful catalysts can be employed and can be optionally removed by passing the product through an app.o~liate ion exchange or absorbing media. Examples of other useful catalysts include but are not limited to, essentially any medium or strong acids with pKa below 8, preferably in the range15 of from 2 to 5, such as, sulfonic acids; alkali bases; ammonium salts; tin containing compounds, such as, dibutyltin dilaurate, dibutyltin ~ cet~te, dibutyltin dioctoate and dibutyltin dioxide; titanates, such as, tetraisopropyl titanate, TYZOR~ tetrabutyl titanate supplied by DuPont Company of Wilmington, Delaware, aluminum titanate; aluminum chelates, and zirconium 20 chelate.
Typically the silylation reaction is conducted in a substantially moisture free atmosphere, usually under a blanket of an inert dry gas, such as nitrogen. The reaction mixture which includes the diol and disilane monomers, optionally with a catalyst, is heated for several hours, typically in the range of from 3 to 8 hours, at a 25 temperature ranging from 60~C to 200~C with the ~ till~tion and removal of the low boiling, volatile reaction byproduct, such as an alcohol, typically methanol.
The progress of reaction is monitored by measuring the amount of the byproduct alcohol collected, reaction mixture viscosity changes, and optionally by substrate conversion and product formation by using conventional gas chromatography, 30 nuclear mass resonance and mass spectroscopy. Optionally, to minimi7- color in the resulting reactive silane oligomer, some conventional methods may be employed, such as, by adding anti-color additives cont~ining active P-H groups to the reaction mixture or by filtration of the reaction mixture through active carbon, silica or other standard decolorizing media. To reduce the VOC of the resnlting 35 reactive silane oligomer, the process of the invention is preferably carried in the absence of solvent. However, to further reduce the viscosity of the oligomer, a small amount, generally less than 50 percent by weight percent based on the total weight of composition of an organic solvent, such as aliphatic hydrocarbon, CA 022~3098 1998-11-09 preferably methylethyl ketone, xylene, ether, ester may be added. Typically, thereactive silane oligomer made by the process of the present invention useful forhigh solids coatings has viscosity in the range of from 1 to 10,000, preferably in the range of from 10 to 5000, more preferably in the range of from 10 to 5000, all 5 in centipoise as measured by using ICI cone and plate viscometer supplied by Gardner Laboratory.
The reactive silane oligomers are generally storage stable. To enhance the storage stability, the reactive silane oligomers are preferably stored in airtight containers to prevent the introduction of moisture. Thus, conventional moisture 10 scavengers, such as, orthoformates, orhto~ret~tes or some alcohols, p,~;feldbly propanol or butanol may optionally be added to further extend the storage stability. The storage stability may be further enh~n~e~l by storing the reactive silane oligomers in sealed containers under dry inert gas, such as, nitrogen.
Moreover, it is desired for improved storage stability to have the stored reactive 15 silane oligomers to be essentially free of any catalyst that were used during the oligomerization process.
The present invention is also directed to a reactive silane oligomer made according to the process of the invention. Thus, a reactive silane oligomer of the following formula is obtained when the unsymmetrical difunctional silane 20 monomer is contacted with the diol monomer:
XsY 525i --/~5--R2 _~p--siyP2 --O--R --O--SiYP2 It;p R ~s SiY 2X
Rs--~--R3 H /;
A reactive silane oligomer of the following formula is obtained when the unsymmetrical difunctional silane monomer is contacted with water:
XsYs25i--Cs--R2_Cp--SiYP2 0--SiYP2--Cp--R2_Cs--SjyS Xs Reactive silane oligomer mixtures, particularly first order homologs enriched in low molecular weight oligomers, preferably with GPC weight average molecular weight in the range of from 500 to 3000 are preferred.
The present invention is further directed to a coating colllposilion, such as, an automotive coating composition, cont~ining the reactive silane oligomer, as areactive diluent. Typically, the coating composition contains in the range of from 3 to 90, preferably in the range of from 10 to 90 and more preferably in the range _ CA 022~3098 1998-11-09 of from 20 to 80, all in weight percentages based on the total weight of the composition of the reactive silane oligomer to produce a coating composition having high solids in the range of from 40 percent to 100 percent, preferably in the range of from 50 percent to 100 percent and more preferably in the range of from60 percent to 100 percent; low viscosity in the range of from 10 to 3000, preferably in the range of from 10 to 2000 and more preferably in the range of from 10 to 1000, all in centipoise. B, using the reactive silane oligomers of the present invention in a multi-component coating composition, the degree of miscibility of the multiple polymeric components of such a coating composition is 10 significantly improved.
The coating composition containing the reactive silane monomer may contain additional conventional additives in suitable amounts. Such additives include pigments, stabilizers, rheology control agents, flow agents, toughening agents and fillers. The use of such additional additives will, of course, depend on 15 the intended use of the coating composition. Fillers, pigments, and other additives that would adversely effect the clarity of the cured coating will not be included if the composition is intended as a clear coating.
The reactive silane oligomers made in accordance with the process of this invention is suitable for coating compositions containing a variety of conventional 20 binders, such as, acrylic polymers as solutions or dispersions; polyisocyanates;
polyolefins, polyesters.
If desired, the coating compositions containing the reactive silane oligomer may also include conventional co-solvents, generally organic solvents in amountsthat do not produce high VOCs. Some of such solvents are aromatic 25 hydrocarbons, such as, petroleum naphtha or xylenes; ketones, such as, methylamyl ketone, methyl isobutyl ketone, methyl ethyl ketone or acetone; esters, such as, butyl acetate or hexyl acetate; and glycol ether esters, such as, propylene glycol monomethyl ether acetate.
The reactive silane oligomers are particularly suitable for coating 30 compositions used in automotive OEM and re~lni~h~s, as primers, basecoats, undercoats and overcoats. These oligomers may be also used as reactive diluents in high solids coating compositions used in marine applications, Illailll~.,ancecoatings, or coating compositions, such as those used in coating metal substrates, such as steel and aluminum or non-metallic substrates, such as, wood and 35 concrete.
CA 022~3098 1998-11-09 EXAMPLES AND PROCEDURES
F,Y~nPIe 1 (Dif ~nct~ al Silane Monomer 1) A 2-neck 100 ml round-bottom flask was equipped with a magnetic stirring bar, heating mantle, solids addition funnel, and condenser. The condenser was fitted with a Claisen adapter and a polytetrafluoroethylene-clad thermocouple was inserted through the Claisen adapter and cond~nser to reach the liquid layer of the flask. The other arm of the Claisen adapter was connected to a 50 ml liquid addition funnel fitted with a Dewar condenser. The entire assembly was purged with nitrogen prior to the reaction and a positive pressure of nitrogen was 10 maintained during the reaction.
The round bottom flask was charged with 4-vinyl-1-cyclohexene (22 g, 0.20 mole). The solids addition funnel was charged with 3g of Vazo~64 initiator,supplied by DuPont Company of Wilmington, Delaware. The liquid addition funnel was charged with trichlorosilane (57 g, 0.42 mole). The condenser on the 15 flask and the condenser on the solids addition funnel were cooled to - 10~C.
Stirring was started and the flask contents were heated. Once the flask temperature exceeded 90~C, enough trichlorosilane was added to bring the flask temperature to about 85~C. Small quantities of Vazo~64 initiator from the solidsaddition funnel were added intermittently to the reaction mixture. The 20 telllpelature was maintained between 85-95~C by adding trichlorosilane and small amounts of the initiator as needed.
Excess trichlorosilane in the reaction mixture was evaporated by passing nitrogen over the reaction mixture and recondensing trichlorosilane in the liquid addition funnel. At this point, the temperature was allowed to rise to 125~C, then 25 held for 1 hour. The total reaction time was 15 hours. The reaction mixture was then cooled to ambient temperature and the product isolated by standard inert atmosphere techniques. After isolation, the GC analysis, using decane as an internal standard, indicated that the vinylcyclohexene was consumed giving both monosubstituted product: 4-(2-trichiorosilylethyl)cyclohex-1-ene and isomers 30 thereof and disubstituted product: 4-(2-trichlorosilylethyl)-1-trichlorosilylcyclohexane and isomers thereof. Bis(trimethoxysilylated) reactivemonomer, namely 4-(2-trimethoxysilylethyl)-1-trimethoxysilylcyclohexane (4-VCHSi2), was obtained by a conventional methoxylation of the reaction mixture and then isolated by a vacuum lli.ctill~tion.
ExamPle 2 (Difunctional Silane Monomer 2) A mixture of 5-vinyl-2-norbornene (100 g, 0.83 mole), trichlorosilane (320 g, 2.36 mole) and platinum divinyl complex supplied by Gelest, Inc., of Tullytown, Pennsylvania (0.6 g 2-3 % in xylene) was heated in a pressure reactor CA 022~3098 1998-11-09 at 115~C for 4 hours. The excess trichlorosilane was stripped under vacuum. A
gas chromatography analysis showed the disilylated product purity to be greater than 96 %. To the reaction product ,a mixture of anhydrous methanol (115 g, 3.6 mole) and trimethylorthoformate (530 g, 5.0 mole) was added dropwise under vacuum. After the addition was complete, triethylamine (15 g, 0.15 mole) was added and the reaction mixture was refluxed for 2 hours. The volatiles were distilled off and the solids were filtered off. The reaction mixture was distilled at 80-100~C under a vacuum of 0.03-0.10 Torr, collecting about 10 % of the first fraction (forecut). A gas chromatography, mass spectroscopy (K+IDS) and lH
10 NMR analysis indicated the products having the desired disilane structure with >
97 % purity composed of four isomers in ratio 7/113/1 (measured by GC). The monomer obtained, namely 5-(2-trimethoxysilylethyl)-trimethoxysilylnorbornane, (280 g) was a colorless liquid having a viscosity of < 0.1 poise at room temperature.
Oli~omer of ExamPle 3 In a five-liter flask equipped with a magnetic stirrer, Vigreux 287300 fractional distillation head, supplied by Kontes under a nitrogen blanket, a reaction mixture of hydrogenated bisphenol A HBPA (700g, 2.91 mole), difunctional silane monomer 1 of Example 1 above-(2400 g, 6.82 mole of 1 4-VCH-Si2), 20 Nafion'9 NR-50 (100 g) catalyst supplied by DuPont Company of Wilmington, Delaware and trifluoroacetic acid (TFAA, Sg) was heated at 100-120~C. After about 6 hours, the pot temperature was increased from 105 to 119~C and about 240 ml MeOH was collected as a byproduct. The resulting crude reaction product had a viscosity of 12 poise, color a=-1.3, b=+6.4 (as measured by Minolta 25 Colorimeter). The crude product was diluted with about 500 ml hexanes, filtered through a multilayer system composed of: a Whatman 50 filter paper supplied by VWR Scientific Products of Philadelphia, Pennsylvania: silica gel desiccant, grade 12 (EM-SX0143J-3); silica gel 60 (EM#9385-3) supplied by VWR Scientific Products; decolorizing carbon supplied by VWR Scientific Products, Norit 211 30 (EK-1133099) supplied by VWR Scientific Products. Volatiles were removed in 1 hour at 75~C under vacuum (20 Torr) on a rotary-evaporator supplied by VWR
Scientific Products. The resulting reactive silane oligomer obtained by reactingthe diol with the difunctional silane monomer and water had a yield of 2700 g, viscosity of 15 poise, Mn = 1750, Mw/Mn = 1.45 (as det~".~hled by Matrix 35 Assisted Laser Desorption Ion Mass Spectroscopy (MALDI MS), color of a=-0.79, b=+ 3.8 (as determined by Minolta Colorimeter).
The following is a representative reaction mech~ni~m, based on the foregoing Example 3 for specific oligomerization providing a narrow CA 022~3098 1998-11-09 polydispersity oligomer mixture enriched in low oligomers and particularly the desired reactive silane trimer, which was a 4-(2-trimethoxysilylethyl)- 1-trimethoxysilylcyclohexane/hydrogenated bisphenol A (hereafter-VCH-Si2/HBPA/VCH-Si2):
Scheme 1. Hybrid silane reactive oligomers in the VCH-SiJHBPA/H20 system.
HO~' + (MeO)3Si~Si(OMe)3 + H20 HBPA VCH-Si2 OMe OMe OMe OM~
XQ~,OSi~S,I-- Y + Ml OSi~Si-- OMe - OMe n - OMe ll where, X y la: ( MeO)3Si-VCH-(MeO)2Si- OMe Ib: (MeO)3Si-VCH-(MeO)2Si-O-Si(OMe)2-VCH-(MeO)2Si- OMe Ic: (MeO)3Si-VCH-(MeO)2Si-O-Si(OMe)2-VCH-(MeO)2Si- O-Si(OMe)2-VCH-Si(OMe)3 Id: H OMe n = 1 , 2, 3...
MALDI and LDI MS analysis revealed that the reactive silane oligomers were composed of 5 homologue series with several major components (22%) of molecular weights in the 350-3000 range (Example 3, Table 1). Data indicated that the final products were combinations of two VCH-Si2 silane oligomers, i.e.,by silication of HBPA and by hydrolysis/condensation with adventitious H2O
shown in Scheme 1.
Although MALDI discrimin~tes against low molecular mass components, combined with GC, it gave a good approximation of the oligomeric composition.
The reactive hybrid oligomers contain 13 major components (22 wt %) (Example 3, Table 1), which represented 5 homologue series (Scheme 1). There are three oligomer classes, i.e., unreacted VCH-Si2 (~25 wt %), HBPA/VCH-Si2 oligomers (~Ia+Id ~ 50 wt %) and H2O/VCH-Si2 oligomers ( +Ic+II(n>~) ~ 25 wt %).
20 The oligomerization process was not complete, because ~6% hydroxyl groups of HBPA remained unsilylated in the Id oligomers. At higher conversions, oligomer viscosity drastically increased, which is detrimental for coating reproducibility and VOC. There are three types of reactive bonds to the silicon, which determine thereactivity/stability balance of the hybrid oligomers, i.e., original Si-OCH3 (88.5 25 mol %), Si-OC(cyclohexyl in HBPA) (9.3 mol %) and Si-OSi (2.2 mol %) from adventitious H2O, which were in the 1/0.11/0.025 molar ratio, respectively. The CA 022~3098 1998-11-09 oligomers had a narrow polydispersity (Mw/Mn < 1.5 by MALDI at Mn = 1800), which is critical for high solidsAow viscosity balance and good compatibility with other coating composition components. The key to achieving the narrow Mw/Mn is a selective oligomerization pattern due to the asymmetrical VCH-Si2 structure, 5 which had two trimethoxysilyl groups of different reactivities. The silicon group attached to the primary carbon atom (Cp)was significantly more reactive than thesilyl group connected to the secondary carbon atom (Cs) of the cyclohexane ring.Table 1 shows the major col,lponents (--2%) of the silane reactive oligomers in the VCH-Si2/HBPA/H2O system, as detellllined by MALDI MS
10 (Scheme 1) of example 3.
Example 3 of Table 1.
Oligomer II Id II Ia II Id Ib Ia Ic Ib Ia Ib Ia DP(n) 1 1 2 1 3 2 1 2 1 2 3 3 4 M.W. 352 560 658 880 9641088 11861408 14921714 19362242 2464 (wt %) 233 2.7 9.5 28 3.4 2.4 4.8 11 2.1 3.6 5.5 1.9 2.5 (mol %)46 3.4 10 22 2.5 1.6 2.8 5.5 1.0 1.5 2.0 0.6 0.7 SiOCH3b27.41.7 0.122.3 3.4 1.4 3.9 7.6 1.8 2.6 3.5 1.2 1.5 SiOCHBPA 0 0.3 0 4.5 0 0.3 0.6 1.6 0.2 0.4 0.8 0.2 0.3 SiOSi 0 0 1.0 0 0.5 0 0.3 0 0.2 0.1 0 0.1 0 a) by GC
b) SiOCH3 (mol %) = 100%xSiOCH3/3x ~Si (mol/mol) 15 SiOCHBPA (mol %) = 100%xSiOCHBPA/3x~;Si (mol/mol) SiOSi (mol %) = 100%xSiOSi/3x~Si (mol/mol) c) Dp (n) degree of polymerization Oli~omers of ExamPles 4-16 The procedure described earlier in Example 3 was followed in plepaling 20 the oligomers of Examples 4-16 shown in Table 2 below, where Component I (as in Scheme 1, shown above) is 4-VCH-Si2/HBPA.
. .
CA 022~3098 1998-11-09 Table 2 Ex. A Ba ca D E Fb Gc HC I J Kd 4 1.17 3.1 0.19 119 ,6 22 73 22 1.8 s 1.17 3.1 o.ls 120 5 86 120 7 89 66 0.8714 3.9 1.2f 6 1.17 3.1 o.l9 120 3 82 120 s 86 64 0.8712 2.7 0.7f 7 1.20 0.77 0.77 120 5 87 5.6 6.s 120 8 89 6s 0.887.0 7.6 1.8 8 1.20 0.77 120 s 84 6.2 7.s 120 8 89 61 0.827.0 10.1 1.6 9 1.20 0.15 142 2 82 4.9 3.1 42 s 87 60 0.837.3 6.6 0.8 o 1.20 0.15 135 s 87 s.o 2.1 +o.ls136 9 so 60 0.807.6 2.7 O.Se P-Hf 0.78 o.so o.10 140 2 78 80 0.8083 2.9 0.3 2 o.so o.so 0.10 120 5 66 18 8 73 75 o.s 30 2.6 0.8 3 l.lo 3.8 0.15 120 5 87 15 4.7 8 so 82 o.ss19 5.5 2.7 4 1.15 3.8 0.15 120 5 87 lo 6.9 8 so 75 0.9615 8.9 3.7 1.20 3.8 0.15 120 5 89 8.0 5.8 8 92 72 0.9412 8.0 3.
6 1.25 3.8 0.15 120 5 86 5.4 6.6 120 8 89 73 1.037.8 8.s 3.
Ex. means Examples A Molar ratio of disilane to hydroxyls of diol monomers B Catalyst 5 C Catalyst co-component (TFA) D Reaction temperature in degrees Centigrade E Reaction time in hours F byproduct in weight percentage formed during oligomerization G VCH weight percentage conversion 10 H VCH/OH conversion ratio oligomer viscosity in poise J (b) color reading of crude oligomer CA 022~3098 1998-11-09 K (b) color reading of filtered oligomer a Nafion(~) NR-50 catalyst; TFA = CF3CO2H both supplied by DuPont Company of Wilmington, Delaware b MeOH yield (%) = MeOH collected/2XHBPA (mole/mole) X 100%
5 c VCH conversion (%) by GC; VC/OH = VCH conversion/MeOH yield (mole/mole) d color value after filtration through carbon/celite/silica/f1lter paper e color value after filtration through celite/silica/filter paper only f color value with Decolorizer added (P-H = 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide) The forgoing Table 2 illustrates that the oligomer composition and properties, such as optical clarity can be varied widely by varying the molar ratio and the extent of the oligomerization as controlled by the catalyst choice, reaction time and temperature.
The procedure described earlier in Example 3 was followed in p~cp~illg ; the oligomers of Examples 17-20 shown in Table 3 below, where Component I (as in Scheme 1, shown above) is 4-VCH-Si2/HBPA.
Table 3 Ex. A Ba C D E Fb Gc H I Jd 171.20 0.26 105 5 68 4.8 1.3f (Me) 110 7 71 5.2 l.lf 140 9 75 590.94 6.3 1.4f 0.5 181.20 0.30 107 5 79 5.1 1.2f (Me) 145 8 85 530.75 5.6 l.1f o.5e /MS
191.20 0.19 106 5 74 6.0 1.3f (Bu) 135 7 81 580.86 8.1 2.5f 0.10 201.20 0.19 110 5 79 5.3 1.0 (Bu)/ 110 7 80 0.9 MS 138 8.5 84 610.87 7.3 1.2 0.02 Ex. means Examples 20 A Molar ratio of disilane to hydroxyls of diol monomers B Catalyst C Reaction tt;lllpeld~ul~ in degrees Centigrade D Reaction time in hours E byproduct in weight percentage formed during oligom~ri7~tion 25 F VCH weight percentage conversion G VCH/OH conversion ratio H oligomer viscosity in poise (b) color reading of crude oligomer J (b) color reading of filtered oligomer 30 a R4NOH, where R = Me,Bu MS = purified over molecular sieves CA 022~3098 1998-11-09 b MeOH yield (%) = MeOH collected/2X HBPA (mole/mole) X 100%
c VCH conversion (%) by GC
VC/OH = VCH conversion/MeOH yield (mole/mole) d color value after filtration through carbon/celite/silica/filter paper S e color value after filtration through celite/silica/filter paper only f hazy From the forgoing data, it is seen that the reactive silane oligomers of the present invention having low polydispersity are produced when the control of themolar ratios between the difunctional silane monomers, water and the diol 10 monomers as well as the reactivity ratio of disilane to hydroxyls (Cp/Cs) in the claimed ranges is ~l~ili7ed Furthermore, higher the molar ratio, lower will be the viscosity. By including such oligomers in a coating composition, its viscosity is reduced and its miscibility is improved.
Oli~omer of ExamPle 21 A mixture of bis(trimethoxysilyl)-limonene (470 g, 1.24 mole), water (16 g, 0.89 mole) and dodecylbenzenesulfonic acid amine salt (5.0 g) was reacted for12 hours at room telllpe.alu.~ Volatiles (57.6 g) were removed under vacuum.
The cloudy reaction product was diluted with 500 ml of anhydrous hexanes and filtered through dry silica gel 60 and dry decolorizing activated carbon under nitrogen. Volatiles were removed under vacuum. The filtered reaction product was a colorless liquid having viscosity of 6.4 poise, containing c 7 % starting monomer, as measured by GC, a dimer as a major component and a small amount of trimer, as measured by KIDS mass spectroscopy. The reactive silane oligomers obtained by reacting disilylated limonene with water showed significantly enhanced solids residue at 93.6 % vs. that of the starting monomers, when small samples were heated for I hour at 100~C (220~F). Additional reactive silane oligomers were also made by using the foregoing process where the viscosities were measured at 1.0, 1.4, 3.2, 5.2, 6.1, 14, 15 and 16 in poises.
Oli~omer of ExamPle 22 A mixture of 5-(2-trimethoxysilylethyl)-trimethoxysilylnorbornane (290 g, 0.80 mole), water (9.0 g, 0.50 mole) and dodecylbenzenesulfonic acid amine salt (3.0 g) was reacted for 12 hours at room te-~ lul~;. Volatile were removed under vacuum. The cloudy reaction product was diluted with 300 ml of anhydrous hexanes and filtered through dry silica gel 60 and dry decolorizing activated carbon under nitrogen. Volatiles were removed under vacuum. A yield of 170 g the filtered reaction product was obtained. It was a colorless liquid having a viscosity of 1.6 poise, containing < 15 % of starting monomers, as measured by GC, a dimer as a major component and a small amount of trimer, as measured by KIDS mass spectroscopy. The reactive silane oligomers obtained by reacting 5-(2-trimethoxysilylethyl)-trimethoxysilylnorbornane with water showed CA 022~3098 1998-11-09 ~ significantly enhanced solids residue vs. that of the starting monomers, when small samples were heated for 1 hour at 100~C (220~F). Additional reactive silane oligomers were also made by using the foregoing process where the viscosities were measured at 1.2 and 1.5 in poises.
S OliYomer of ExamPle 22 To a two-liter, three-neck flask, equipped with a magnetic stirrer, reflux condenser, addition funnel under nitrogen blanket, a reaction mixture of 2-trimethoxysilylethyl-trimethoxysilylcyclohexane (930 g, 2.66 mole) and dodecylbenzenesulfonic acid aminoplul)allol salt (10 g) was added. With stirring, the contents of the flask were heated at 70~C and water (32 g, 2.0 mole) was added dropwise at the rate 4 g/10 min. After the addition of 16 g water, the reaction mix became cloudy. Nafion~ NRS0 (3.7 g) catalyst was added and then the remaining 16 g water was added over the 10 minutes. The reaction was continued at 70~C for another 12 hours. Volatiles (157 g) were removed at 80~C
under vacuum. The cloudy reaction product was diluted with 400 ml anhydrous hexanes and filtered through dry silica gel 60 (EM Science # 9385-3) and dry charcoal (activated Darco G-60, EM Science # CX0645-1). Volatiles were removed under vacuum. A yield of 483 g of almost colorless filtered reaction product was obtained. It was a liquid having a viscosity of 4.3 poise cont~ining 4 % starting disilane, as measured by GC. The reactive silane oligomers obtained by reacting 2-trimethoxysilylethyl-trimethoxysilylcyclohexane with water showed significantly enhanced solids residue vs. that of the starting monomers, when small samples were heated for 1 hour at 100 ~C (220~F). Additional reactive silane oligomers were also made by using the foregoing process where the viscosities were measured at were 0.6, 0.8, 1.2, 1.6, 2.1 and 3.2 in poises
Claims
1. A process for making a reactive silane oligomer, said process comprising:
contacting one or more unsymmetrical difunctional silane monomers with water, with one or more diol monomers, or with a combination thereof, wherein:
said diol monomer is:
R1-(OH)2, wherein R1 is selected from the group consisting of:
a) C2 to C20 alkylene, cycloaliphatic rings or aromatic rings, each optionally substituted with at least one member selected from the group consisting of O, N, P and S;
b) two or more cycloaliphatic or aromatic rings connected to each other through a covalent bond, or through an alkylene group of 1 to 5 carbon atoms, orthrough a heteroatom, or fused together to share two or more carbon atoms, each optionally substituted with at least one member selected from the group consisting of O, N, P and S; and c) a linear polyester, branched polyester, a combination of said linear and said branched polyesters, polyacrylate, polyolefin, polyether, polycarbonate, polyurethane, or polyamide, each having a GPC weight average molecular weight in the range of from about 200 and 10,000; and said difunctional silane monomer is:
wherein Cp is a primary carbon atom, Cs is a secondary carbon atom and R2 is selected from the group consisting of:
a) C3 to C20 alkylene, C1 to C10 alkyl substituted cycloaliphatic rings or C1 to C10 alkyl substituted aromatic rings, each optionally substituted with at least one member selected from the group consisting of O, N, P and S;
b) C1 to C10 alkyl substituted two or more cycloaliphatic rings, or C1 to C10 alkyl substituted two or more aromatic rings connected to each other through a covalent bond, or through an alkylene group of 1 to 5 carbon atoms, or through aheteroatom, or fused together to share two or more carbon atoms, each optionallysubstituted with at least one member selected from the group consisting of O, N, P
and S; and c) a combination of (a) and (b);
R3, R4 and R5 each is independently selected from the group consisting of:
hydrogen, C1 to C20 alkyl, C1 to C10 alkyl substituted cycloaliphatic rings or C1 to C10 alkyl substituted aromatic rings, each optionally substituted with at least one member selected from the group consisting of O, N, P and S;
X p and X s being independently selected from the group consisting of alkoxy containing 1 to 20 carbon atoms, acyloxy containing 1 to 20 carbon atoms,phenoxy, halogen, amine, amide, urea, imidazole, carbamate, ketoximine, oxazolidinone, and a combination thereof; and Y p and Y s being independently selected from the group consisting of alkyl containing 1 to 12 carbon atoms, alkoxy containing 1 to 20 carbon atoms, acyloxycontaining 1 to 20 carbon atoms, phenoxy, halogen, amine, amide, urea, imidazole, carbamate, oxazolidinone, and a combination thereof;
for producing said reactive silane oligomer having a GPC weight average molecular weight of less than 10,000 and having a polydispersity of less than 3. 2. The process of claim 1 further comprising:
I. adjusting the reactivity ratio (Cp/Cs) between the silane groups (XY2Si-) attached to Cp and Cs in the range of from 1.1 to 100,000;
II. adjusting the molar ratio in of disilane to hydroxy groups the range of from 0.7 to 4 between:
i) said difunctional silane monomers and 2 times water, ii) said difunctional silane monomers and 2 times said diol monomers, or iii) ;
III. increasing in the range of from 50 percent to 100 percent the conversion of said unsymmetrical difunctional silane monomers into said reactivesilane oligomer; or IV) utilizing a combination of said steps I, II, and III.
3. The process of claim 1 wherein said reactivity ratio is increased by substituting one or more hydrogen atoms on carbon atoms connected to Cs with moieties selected from the group consisting of C1 to C20 aryl and alkyl and a combination thereof.
4. The process according to Claim 1 wherein said unsymmetrical difunctional silane monomer has a molecular weight in the range of from 300 to 1500.
5. The process according to Claim 1 wherein said diol monomer has a GPC weight average molecular weight of less than 3,000.
6. The process according to Claim 1 wherein said unsymmetrical difunctional silane monomer is 4-(2-trimethoxysilylethyl)-1-trimethoxy-silylayclohexane, 5-(2-trimethoxysilylethyl)-trimethoxysilylnorbornane, bis(trimethoxysilylated) limonene, or a combination thereof.
7. The process according to Claim 1 wherein said diol monomer is hydrogenated bisphenol A, cyclohexane dimethanol, or a combination thereof.
8. The process according to Claim 1 wherein said unsymmetrical difunctional silane monomer is contacted with said diol monomer, water or a combination thereof, in the presence of a catalyzing amount of a catalyst.
9. The process according to claim 8 wherein said catalyst is selected from the group consisting of fluorosulfonic acid, fluoroalkyl sulfonic acid, trifluoroacetic acid, tetraalkylammonium hydroxide, ammonium hydroxide, sulfonic acid, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate and dibutyltin dioxide, tetraisopropyl titanate, tetrabutyl titanate, aluminum titanate;
aluminum chelate, and zirconium chelate.
10. The process according to claim 8 wherein said catalyzing amount of said catalyst is in the range of from 0.01 percent to 5 percent, all in weight percentages based on the total weight of reaction mixture.
11. The process according to claim 8 further comprising separating said catalyst from said reactive silane oligomer.
12. A reactive silane oligomer made in accordance with the process of claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11.
13. The reactive silane oligomer of claim 12 is of the formula:
when said unsymmetrical difunctional silane monomer is contacted with said diol monomer.
14. The reactive silane oligomer of claim 12 is of the formula:
when said unsymmetrical difunctional silane monomer is contacted with water.
15. A coating composition having a low viscosity and low VOC
comprising a reactive silane oligomer made in accordance with the process of
claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US6499597P | 1997-11-10 | 1997-11-10 | |
| US60/064,995 | 1997-11-10 |
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| Publication Number | Publication Date |
|---|---|
| CA2253098A1 true CA2253098A1 (en) | 1999-05-10 |
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ID=29547862
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2253098 Abandoned CA2253098A1 (en) | 1997-11-10 | 1998-11-09 | Process for producing reactive silane oligomers |
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| CA (1) | CA2253098A1 (en) |
| MX (1) | MX217495B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20200331242A1 (en) * | 2017-12-05 | 2020-10-22 | Cryovac, Llc | Sealable and easy opening polyester films |
-
1998
- 1998-11-09 CA CA 2253098 patent/CA2253098A1/en not_active Abandoned
- 1998-11-09 MX MX9809341A patent/MX217495B/en not_active IP Right Cessation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20200331242A1 (en) * | 2017-12-05 | 2020-10-22 | Cryovac, Llc | Sealable and easy opening polyester films |
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| Publication number | Publication date |
|---|---|
| MX217495B (en) | 2003-11-11 |
| MX9809341A (en) | 2000-04-30 |
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