WO1995033784A1

WO1995033784A1 - Oximino silane terminated polymers and elastomers formed therefrom

Info

Publication number: WO1995033784A1
Application number: PCT/US1995/005473
Authority: WO
Inventors: Dale Russell Flackett; Edward Thanaraj Asirvatham; Chempolil Thomas Mathew
Original assignee: Alliedsignal Inc.
Priority date: 1994-06-07
Filing date: 1995-05-03
Publication date: 1995-12-14
Also published as: CA2190751A1; HU9603384D0; HUT75496A; JPH10502392A; BR9507837A; MX9605594A; NZ285011A; CZ358896A3; EP0764179A1; KR970703377A; CN1149880A; AU2372995A

Abstract

Oximinosilane terminated polymers which are cured at room temperature to become stable elastomers. The polymers have hydrolyzable ketoximino silyl group at each end of each molecule and are prepared by reacting a hydroxyl-terminated liquid polymer with an organic diisocyanate to produce an isocyanate terminated prepolymer. The resulting prepolymer is then converted into a mercaptan terminated polymer either by reacting with a mercapto alcohol or by reacting with an olefinic alkylene alcohol or amine to give an olefin-terminated polymer which is then reacted with a dimercaptan. When the mercaptan terminated polymer is reacted with a vinyl oximino silane or a vinylalkoxyoximino silane, a silane terminated liquid polymer is obtained. Such polymers have improved elongation, moisture resistance, tensile and tear strength properties in adhesive, coating and sealant formulations.

Description

OXIMINO SILANE TERMINATED POLYMERS AND ELASTOMERS FORMED THEREFROM

BACKGROUND OF THE INVENTION

Field of the Invention:

The invention relates to oximinosilane terminated polymers which are cured at room temperature to become stable elastomers. They have improved physical properties such as elongation, moisture resistance, variable cure rate, tensile and tear strength in various formulations. Such polymers have use as adhesives, coatings and sealants.

Description of the Prior Art

It is known in the art that the curing of isocyanate and mercaptan terminated liquid polymers requires amines to form urea/urethanes or peroxides forming disulfides. Both urethane and mercapto type polymers are commonly used in two component sealant systems where the mixing of the main polymer component with a curing catalyst or reactive component is essential prior to use. Incorporating oximesilanes in these liquid polymers has the advantage of moisture cure vulcanization due to the extreme reactivity of oximesilanes with moisture. Room temperature moisture cure of oximesilane terminated polymers eliminates the need for handling toxic isocyanates and peroxides. In the silicone sealant industry, polysiloxane having hydrolyzable silicon-end groups are often used in single-component sealant formulations. Upon exposure to the atmosphere, the polymer undergoes rapid vulcanization with atmospheric moisture. Due to the high cost of polysiloxane polymers, it is desirable to use low-cost organic polymers such as polyethers, polyesters and polysulfides as the polymer backbone. Among the commercially available liquid polymers, silane terminated polymers are the most desirable due to the ease of curing with atmospheric moisture and their low odor and toxicity. However, these silane terminated polymers are in limited use because of their poor physical properties such as low tensile and tear strengths. Therefore it is desirable to produce organic liquid polymers which cure to become elastomeric materials with faster cure rates, hydrolytic stability, good elongation, high tensile and tear strength characteristics. U.S. Patent 3,317,461 discloses oximesilane terminated polysulfides made by reacting a mercaptan terminated polysulfide with a silane having hydrolyzable groups and at least one olefinic double bond. These polymers, when cured, do not have high tensile and tear strength due to the lack of urethane groups. U.S. Patent 4,960,844 discloses silane endcapped polymers with urethane groups in the polymer chain. Hydrolyzable groups attached to the silicon atom are alkoxy groups with lower alkyl groups.

The silane terminated polymers of this invention are easily cured at room temperature in the presence of normal humidity to a hydrolytically stable solid elastomer having high tensile and tear strength and low compression set. No catalyst is required for this cure to take place although a wide variety of catalysts known to the art can be used to decrease cure times. An object of the invention is to provide an organic liquid polymer endblocked with silanes containing ketoximes as the hydrolyzable groups that can be cured at room temperature into a rubber-like elastomer or leathery adhesive when exposed to moisture. SUMMARY OF THE INVENTION The invention provides oximinosilane terminated polymers having the formula:

R4

I R- I -0-C-NH-R¹-NH-C-X-R²-Y-CH2CH2-Si- (0-N=C)_n

I 0 0 (R³)_m R⁵ I

L - Jp

having an average molecular weight of at least about 600; wherein R is an organic polymer containing a backbone of polyether, polythioether or polyester, R¹ is a divalent organic radical, R² is an alkylene group having at least

3 carbon atoms, X is 0 or N ^ where R⁶ is either hydrogen or a monovalent lower alkyl group, Y is sulfur or S-R⁷-S where R⁷ is an alkylene thioether having 4-12 carbon atoms, alkylene having 2 to 10 carbon atoms, or a substituted cyclohexyl ring group having the formula:

CH

CH₂ CH

/ \ / \ CH₂ CH-CH₂-CH₂' or CH₂ CH-

CH₂ CH- CH₂ CH_:

\ / \ / CH CH

CH

/ \ CH CH-

R³ is an alkyl radical of 1 to 7 carbon atoms or an alkoxy radical of 1 to 6 carbon atoms and R⁴ and R⁵ are independently a saturated straight chain or branched alkyl radical of 1 to 7 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl and amyl, or R⁴ and R⁵ taken together form a cyclized group, p is 2 to 3, m is 0 to 2, n is 1 to 3 and the sum of m and n is 3.

The invention further provides a method for the production of the above oximinosilane terminated polymers. A prepolymer is formed by reacting a hydroxyl- terminated polymer with an organic diisocyanate to produce an isocyanate terminated polymer. The isocyanate terminated polyol is reacted with an olefinic alcohol or amine in which the olefinic group is separated by at least one carbon atom to give olefin terminated polyether polyol. One then reacts the olefin-terminated prepolymer with a dimercaptan and a vinyloximesilane.

The invention still further provides a method for the production of the above oximinosilane terminated polymers by reacting the isocyanate terminated polyol with a mercapto alcohol to produce a mercaptan terminated polymer; and then reacting with a vinyloxime silane. The invention also provides a formulated sealant, coating, foam or adhesive composition which comprises the above oximinosilane terminated polymer in admixture with a plasticizer, filler, .and moisture scavenger as well as an optional adhesion promoter, catalyst, rheology modifier and/or crosslinker.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The invention encompasses organic polymers, having hydrolyzable ketoximino silyl group at each end of each molecule as is shown by the formula described above. The ketoximinosilane-terminated polymers are prepared by forming an isocyanate terminated polymer, or prepolymer, having the general formula: R [0- C-NH- R¹ -N=C=0] _p

II

0 where R, R¹ and p have the same meaning as above, by reacting a hydroxyl terminated polymer with an organic diisocyante. In the preferred embodiment, the polymeric backbone, noted as R in the general formula can be such as hydroxyl terminated polypropylene oxide polyols, polybutyleneoxide glycol polyols, polytetramethylene glycol polyols, polyester polyols, polythioether polyols, polyalkylene glycol co-polymer polyols, and polyalkylene glycol-polyester copolymer polyols. These hydroxyl terminated polyols are reacted with an organic diiso¬ cyanate following a procedure known in the prior art. Some examples of the organic diisocyanates are toluene diisocyanate, diphenylmethane 4,4'-diisocyanate, 1,6- hexamethylene diisocyanate and isophorone diisocyanate. The prepolymers can be converted to mercaptan- erminated polymers by either 1) reacting with a mercapto alcohol in which the mercaptan and the hydroxyl groups are separated by at least two methylene groups or 2) or reacting with a olefinic alkylene alcohol or amine of at least three carbon atoms wherein the olefin group is separated from the hydroxyl or amine by at least 1 carbon atom. The resulting olefin-terminated polymer is then reacted with a dimercaptan, in which the mercaptan functionality is separated by alkylenes, alkylene ethers, alkylene thioethers, alkylene esters and substituted cyclohexyl rings to .give mercaptan-terminated polymers. Hydrogen sulfide can also be used to obtain the mercaptan terminated polymer by using at least 1 mole for each equivalent of olefinic polymer to ensure all olefin functionality is terminated with the mercaptan groups. Because of their greater availability, the preferred dimercaptans are 1,2-ethane dithiol, 1,6-hexane dithiol, 1,10-decane dithiol, 2-mercaptoethylether, 2- mercaptoethylsulfide, glycol dimercapto acetate, glycol dimercapto propionate, p-menthane-2,9-dithiol and ethylcyclohexane dithiol. Preferred mercapto alcohols are 2-mercaptoethanol, 3-mercapto-1-propanol. The reactions described above are disclosed in U.S.Patents 3,923,748, 4,366,307 and 4,960,844 the disclosure of which are incorporated herein by reference. Radical initiated coupling reaction between the olefinic compound, i.e., the olefin terminated polymer and an organic compound with 2 to 4 but at least two mercaptan groups will give mercaptan terminated polymer as described in the following equation:

[R⁷-(SH)₂.₄] + R- [0-C-NH-R¹-NH-C-X-CH2-C=C]p -->

R- [0-C-NH-R¹-NH-C-X-CH2-C-C-S-R⁷- (SH)^' ₁.₃].

II

0 0

The above straight forward reaction is catalyzed by 0.1 to 1.0 weight % of radical initiators such as organic peroxides or azobis alkyl nitriles. The reaction temperature is maintained between 55°C and 120°C with the preferred range between 55°C and 85°C.

When the mercaptan terminated polymer is reacted with a vinyl oximino silane, vinylalkyloximino silane, vinylaryloximino silane, vinylalkylalkoxyoximino silane, vinylalkoxyoxi ino silane or vinylarylalkoxyoximino silane, a silane terminated polymer is obtained which is preferably a liquid and preferably has a molecular weight of from about 1200 to about 100,000. This is also a radical initiated addition reaction between the mercaptan group of the polymer and the olefin group of the vinyloximesilane. The preferred silane has the formula, R4

H2C=CH- Si - (0 -N=C) _n i I

(R³ ) m R₅

in which R³, R⁴, R⁵, m and n have the same description as set forth above. The ketoximino silane terminated liquid polymers of the present invention are different from the prior art by having urethane groups and the sulfur atoms separated by just 2 or more carbon atoms in the polymer backbone and also because of at least one fast hydrolyzable neutral ketoximino group attached to the silicon atom.

In the compounding of an adhesive, coating, foam or sealant composition, the oximinosilane terminated polymers may be used alone, but more preferably are blended with additives known in the art for the preparation of such adhesives, sealants and coating compositions. Such non-exclusively include plasticizers, fillers, reinforcing agents, moisture scavengers, rheology modifiers, colorants, uv stabilizers, fungicides, mildewcides, antimicrobial agents, antioxidants, polymers, crosslinkers, coupling agents, adhesion promoters, and catalysts, thixotropic agents, flame retardants, thermal and electrically conductive fillers, blowing agents, surfactants, heat stabilizers, and solvents etc. to tailor the composition to a specifically desired application. These usually may be added at any stage of the mixing operation but care should be taken to add them under anhydrous conditions to avoid introducing additional moisture.

In the preparation of a formulated adhesive, coating, foam or sealant composition, the amount of polymer to be used in this invention ranges from above 5 to about 90 percent by weight of the total composition but preferably ranges from about 15 to about 60 percent by weight of the total composition.

The polymer may be used to create a foam by those skilled in the art through the use of a low boiling point liquid or other suitable blowing agent, an example of which is 1,1-dichloro-l-fluoro ethane in combination with a surfactant as a foam stabilizer.

The composition can contain a filler which may be a reinforcing silica filler, a semireinforcing filler, a non-reinforcing filler or mixtures thereof. Examples of reinforced silica fillers are fumed silica and precipitated silica. Examples of useful silica fillers •are described in U.S. Patents 3,837,878; 2,938,009; 3,004,859, and 3,635,743 which are incorporated by reference. The amounts of reinforcing filler ranges from 0 to about 50 percent by weight of the total composition, preferably from about 0 to about 14 percent by weight and most preferably 2 to 8 percent by weight. Use of reinforcing fillers imparts increased tensile strength of the cured composition as well as providing thixotropic character to the uncured composition. A non-reinforcing or semi-reinforcing filler can also be used at levels up to 75%. These include fillers such as calcium carbonate and ground quartz. Other semi-reinforcing fillers or extending fillers which are known in the art may be used. These include, but are not limited to silica aerogel, diatomaceous earth, iron oxide, titanium oxide, aluminum oxide, zirconium silicate, calcined clay, magnesium oxide, talc, wollastonite, hydrated alumina, and carbon black. The total amount of all fillers in the composition ranges from 0% to about 60% and preferably from about 6% to about 55% by weight of the overall composition.

Methyl tris- (methyl ethyl ketoximino) silane, vinyl tris- (methyl ethyl ketoximino) silane and tetrakis- (methyl ethyl ketoximino) silane are the predominant oxime silanes used commercially as crosslinkers in oxime RTV compounds and are used to speed the cure. Also useful as crosslinklers and herein are those silanes described in U.S. patent 3,189,576 and is hereby incorporated by reference. Crosslinker can be present in an amount of from about 0 to about 10 percent by weight of the total composition, however from about 3 to about 7 percent by weight is preferred and from about 3 to about 6 percent by weight is most preferred. Tetrafunctional alkoxy- ketoxime silanes as disclosed in U.S. Patents 4,657,967 and 4,973,623 can also be used as crosslinkers and are incorporated herein by reference. U.S. Patent 4,705,877 describes aminohydrocarbyl substituted ketoximinosilanes as coupling agents and is incorporated herein by reference.

Additionally, known in the art are organofunctional silanes as adhesion promoters non-exclusively including gamma-aminopropyltriethoxy silane and gamma- aminopropyltrimethoxy silane as described in U.S. Patent 4,720,530. Other adhesion promoters may include 3- glycidoxypropyl trimethoxy silane or gamma-mercaptopropyl trimethoxy silane. The amount of adhesion promoter may range from about 0 to about 5.0 percent by weight of the total composition. Preferably 0.5 to 1.5 percent by weight of the total composition is used.

The composition may further contain an optional catalyst which accelerates the reaction of the polymer. Examples of catalysts, non-exclusively include organotin carboxylates such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate, dibutyltin maleate, dialkyl tin hexoates, dioctyltin dilaurate, iron octanoate, zinc octanoate, lead octanoate, cobalt naphthenate, amines such as diamine, and titanantes. Dibutyltindilaurate is the preferred catalyst. Use levels of catalyst can range from 0 to about 2.0 percent by weight of the total composition, preferably about 0.05 to about 1 percent and most preferably from about 0.2 to about 0.5 weight percent.

The composition may also contain an optional plasticizer to improve the extrusion properties of the composition and to modify the modulus of the cured composition. Such include phthalates, adipates, and aromatic hydrocarbons. Suitable plasticizers include dibutylphthalate, dioctylphthalate, triarylphosphate and substituted analogs thereof. The plasticizer is added in an amount ranging from 0 to 50 weight percent based on the overall composition, preferably from about 10 to about 30 weight percent. Preferred viscosity of the plasticizer ranges from about 100 to about 1000 cps. at 25°C.

Common uv stabilizers include benzophenones and hydroxyphenyl benzotriazoles families, including hydroxyphenyl benzotriazole monomers and dimers. Hydroxyphenyl benzotriazole monomers are disclosed in U.S. Patents 3,204,896; 5,097,041; 4,943,637 and 5,104,992. 2-hydroxy-4-alkoxybenzophenones are useful uv absorbers and light stabilizers. U.S. Patents 3,399,237 and 3,310,525 show compounds having benzophenone functional groups. The uv stability of such materials is improved by mixing the polymer with from about 0.1% to about 5 % based on the weight of the polymer composition of the asymmetrical dimer of this invention. Moisture scavengers are preferably present in an amount of from 0 to about 5% by weight of the composition. Suitable moisture scavengers non-exclusively include trifunctional or greater oximinosilanes, molecular sieves and other moisture reactive materials. Rheology modifiers are preferably present in an amount of from 0 to about 5% by weight of the composition. Suitable rheology modifiers non-exclusively include smectic clay, fumed silica, castor oil, castor wax and fibers.

Preferred colorants for this invention are pigments and dyes. Examples of colorants are titanium dioxide, carbon black, silica, zinc oxide, and clay. It is preferably present in an amount ranging from about 5% to about 10% based on the weight of the solids in the layer. The composition also may contain an optional bacteriostat/fungistat. The most preferred compound is acetoxy-dimethoxydioxane. Such are preferably present in an amount of from about 0.001% to about 1.0% by weight of the composition.

Solvents useful for forming coating compositions include essentially any inert organic solvent that is a solvent for the other composition components. Solvents may be ethers, ketones, hydrocarbons and halocarbons, among others. The amount of solvent can be determined by the skilled artisan depending on the end use. The other optional components may be present in an amount ranging from about 0 to about 10 weight percent based on the entire composition.

The composition of the present invention can be used in the form of a one component room temperature curing composition which is produced by mixing the above described components and various additives in the absence of moisture and storing in a closed vessel which is impervious to moisture. The composition is cured to an elastomer by exposure to atmospheric moisture at the time of use when the package is broken.

The following non-limiting examples serve to illustrate the invention.

EXAMPLE 1 To 2000 grams (0.5 mole) of polyoxypropylene diol having a molecular weight 4000 is added 174.5 grams (1.0 moles) of toluene diisocyanate. The reaction is carried out in the presence of nitrogen in a 3L reaction kettle equipped with a mechanical stirrer and three neck lid. The mixture is heated to 80°C for 1-2 hours in the presence of 2.26 grams DABCO catalyst solution (24% in toluene). To the above obtained prepolymer is mixed 58.1 g (1.0 moles) of allyl alcohol in the presence of 9.3 grams DABCO solution and heated at 80°C for 1-2 hours with continuous stirring. The completion of the reaction is characterized by disappearance of -NCO peak in IR and GPC. To the above obtained olefinic terminated polymer is added 94.2 g (1.0 moles) of 1,2-ethane dithiol and 4.65 g azobisisobutyronitrile and heated to 80-95°C for two hours with slow stirring to prevent vortex formation. The mercaptan content of the polymer is confirmed by iodometric titration and the mercaptan equivalent weight is calculated. To the mercaptan polymer thus obtained is added 267.5 g methyl vinyl bis(2-butanone oxime) silane (1.05 moles, 95% assay) and 5.18 g azobisisobutyronitrile initiator and the mixture is heated at 80-95°C for 2 hours with continuous stirring. The nitrogen blanket is kept throughout the reaction. The M.W. of the polymer at different steps is determined by GPC. The final polymer is moisture sensitive therefore is stored in a nitrogen flushed closed container. The viscosity of the polymer ranges between 900-1100 poise at 23°C (90,000-110,000 cps) . EXAMPLE 2 An olefin terminated polymer is prepared following the procedure described in Example 1. The pre-polymer is prepared from 1,100 grams of polypropylene glycol polyol with hydroxyl number of 28.8, 96 grams of toluene diisocyanate and 0.30 grams of DABCO. The olefin terminated polymer is prepared by reacting the prepolymer with 33.6 grams of allyl alcohol and 1.20 grams of DABCO. To the above polymer, 102.0 grams of ethylcyclohexyldimercaptan and 2.4 grams of azobisisobutyronitrile are added and heated for 4 hours at 80°C to give mercaptan terminated polymer which is then reacted with 147 grams of methyl vinyl bis (2- butanone oxime) silane and 3.0 grams of azobisisobutyronitrile (radical initiator) at 80°C for 4 hours to give oxime silane terminated polymer.

EXAMPLE 3 An olefin terminated polymer is prepared according to the procedure described in Example 1. 1300 Grams of polypropylene glycol polyol with a hydroxyl number of 28.8, 130.5 grams of toluene diisocyanate and 0.36 gram of DABCO catalyst are heated at 80°C for 1 1/2 hours to give isocyanate terminated polymer which is converted to olefin terminated polymer by reacting with 43.6 grams of allyl alcohol and 1.26 grams of DABCO catalyst at 80°C for 4 hours. To the above polymer, 178.8 grams of ethylene bis (3-mercapto propionate) and 3.0 grams of azobisisobutyronitrile are added and heated at 80°C for 4 hours to give mercaptan terminated polymer which is then reacted with 191 grams of methyl vinyl bis (2-butanone oxime) silane and 3.4 grams of azobisisobutyronitrile at 80°C for 4 hours to give oxime silane terminated polymer. EXAMPLE 4 2,4-Toluene diisocyanate (0.123 moles, 21.46 gm) having 20% 2,6-toluene diisocyanate i.e. TDI 80/20 and 0.33 gm 24% solution of DABCO are added to polybutyleneoxide having a molecular weight 4878 (300 g, 0.0615 moles) under nitrogen atmosphere. The mixture is heated to 80°C for 1-2 hours. Allyl alcohol (7.15 gm, 0.123 moles, 99%) and 1.31 gm DABCO solution are added to the above mixture and heated to 80°C for 1-2 hours with continuous stirring. To the polymer thus obtained is added (146 gm 0.123 moles, 99%) 1,2-ethane dithiol and 0.51 gm azobisisobutyronitrile and heated for 2 hours at 80-90°C. Finally (32.9 gm, 0.1292 moles, 95%) methylvinyl bis(2- butanone oxime) silane and 0.56 gm AIBN are added to the mercaptan polymer and heated for 2 hours at 80-90°C. The polymer at different steps is characterized by IR, GPC and volumetric titration. The viscosity of the silyl terminated polymer is 100,000 cps at 24°C.

EXAMPLE 5

To 300 gm (0.14465 moles) propyleneoxide pentanediol and polyester polyol is added 50. 4 gm (0.2893 moles) toluene diisocyanate and 0.37 gm DABCO catalyst solution. The polyester polyol used has a molecular weight of 2074 and hydroxyl number 54.1. The mixture is heated to 80°C for 1-2 hours in a nitrogen atmosphere. Allyl alcohol 16.8 gm (0.2893 moles, 99%) and 1.5 gm DABCO solution is added and heated for 1-2 hours at 80°C with continuous stirring. 27.3 gm (0.2893 mole, 99%) 1,2-ethane dithiol and 0.59 gm AIBN is added to olefin terminated polymer and radical coupling is carried out at 80-90°C for 2 hours with slow stirring. To the mercaptan polymer thus obtained is added 77.4 g (0.3037 moles, 95%) methyl vinyl bis(2-butanone oxime) silane and heated for 2 hours at 80-90°C. The polymer is characterized at different steps by IR and GPC and the -SH content in the mercaptan terminated polymer is determined by volumetric titration. The viscosity of silyl terminated polymer is 140,000 cps. at 24°C.

EXAMPLE 6

297.1 g (0.102 moles) polytetramethyleneglycol having 2914 molecular weight and 385 hydroxy number is melted at 60° and mixed to make a homogeneous liquid and to it is added 356 g (0.204 moles) 80:20 toluene diisocyanate and 0.35 g DABCO solution. The reaction is carried at 80°C for 1-2 hours in nitrogen atmosphere. To this prepolymer is added 11.9 g (0.204 moles) allyl alcohol and 1.45 g DABCO solution. The product is heated to 80°C with continuous stirring for 1 -2 hours. The allyl terminated polymer thus obtained is reacted with 19.2 g (0.2040 moles) 1,2-ethane dimercaptan and 0.55 g AIBN initiator. The temperature of the reaction is kept between 80-90°C for 2 hours. Finally 54.5 g (0.2142 moles) 95% assay methyl vinyl bis(2-butanone oxime) silane and 0.62 g AIBN is added and reacted at 80-90°C for 2 hours. The silyl terminated polymer thus obtained is highly viscous (1 million cps at 24.5°C).

EXAMPLE 7 A polythioether polyol, 300 g (0.15 mole), having hydroxyl number 56 and molecular weight 2000 is reacted with 52.4 g (0.30 mole) of toluene diisocyanate in the presence of 0.37 g DABCO solution at 80°C for 1-2 hours. The prepolymer thus obtained is reacted with 17.4 g (0.30 moles) of allyl alcohol in the presence of 1.5 g DABCO catalyst solution for 1-2 hours. 28.3 g (0.30 moles) of 1,2 ethane dithiol and 0.15 weight% of AIBN are added and stirred slowly for 2 hours at 80-90°C. To this mercaptan terminated polymer is added 93.6 g (0.367 moles, 95% assay) methyl vinyl bis(2-butanone oxime) silane and 0.15 weight % AIBN and reacted at 80-90 C for 2 hours to get oxime terminated polymer having viscosity 220,000 cps at

23 C. Nitrogen atmosphere is kept throughout the reaction process.

Cure Rate Comparison

Cure rate is compared for identical polymers with varying types of silane end capping. The mercaptan terminated polymer prepared as in Example 1 is divided into three reactors designated A, B and C. The polymer in reactor A is capped with methylvinyl bis(methoxy) silane, the polymer in B is capped with methylvinyl bis(ethoxy) silane and the polymer in reactor C capped with methyl vinyl bis(2-butanone oxime) silane as described in Example 1 for ketoximino silane. The capped polymers are prepared as sealants to compare physical properties such as curing rates and strength by the following formu¬ lations and methods.

Formulation 1

COMPONENT WEIGHT %

Polyether polymer of Example 1 30.00

Di-octyl phthalate 24.50

CaC03 42.9 Methyl tri(2-butanone oxime) silane 2.00

Amino propyl triethoxy silane . 0.50 Dibutyl tin dilaurate 0.1

Formulation 2 COMPONENT WEIGHT %

Polyether polymer of Example 1 30.00

Di-octyl phthalate 24.50

CaC03 43.00 Methyl tri(2-butanone oxime) silane 2.00 Amino propyl triethoxy silane 0.50 To a double planetary vacuum mixer are added the polymer and plasticizer. This is mixed under vacuum. Precipitated calcium carbonate is added and mixed under vacuum. Methyloximino silane and amino propyltriethoxy silane (available as A-1100 from OSI) is added to the mixture. Mixing takes place under vacuum. The mixture is discharged into tubes for storage and further evaluation.

Sealant is produced from each polymer using the formulas and methods in Table 1. Cure times, cure though rates and mechanical properties are measured and listed in Table 1. Sealant prepared by formulation 1 or 2 with ethoxy silane capped polymer fails to cure.

Table 1

MECHANICAL PROPERTIES:

POLY^R/FORMITLATION A/l A/2 B/l B/2 C/l C/2 SKIN OVER TIME 210-300 1440-4320 No No 50 135

(Minutes) Cure Cure

TACKFREE TIME 210-300 >4320 50 160

(Minutes)

TENSILE STRENGTH 1.8 No Cure 1.8 1.9

(N/mm2)

ELONGATION 250 250 260

(%)

HARDNESS 45 45 43

(SHORE A)

In the following examples, a number of other polymer backbones are evaluated as starting materials for the silane addition methods and properties are noted as follows. Formulation 3

COMPONENT WEIGHT %

Polyester polymer of Example 5 30.00

Aromatic hydrocarbon oil 24.50 CaC03 43.00 Methyl tri(2-butanone oxime) silane 2.00

A-1100 0.50

To a double planetary vacuum mixer is added 30 parts by weight polymer and 24.5 pbw of plasticizer. This is mixed for 2 to 5 minutes under vacuum. Precipitated calcium carbonate is added and mixed for 15 to 20 minutes under vacuum. Methyloximino silane and A-1100 is added to the mixture. Mixing takes place for approximately five minutes under vacuum. The mixture is discharged into tubes for storage and further evaluation.

Formulation 4

COMPONENT WEIGHT % Polymer of Example 7 30.00

Alkyl aryl phosphate ester 24.50

CaC03 43.00

Methyl tri(2-butanone oxime) silane 2.00 A-1100 0.50

To a double planetary vacuum mixer is added 30 parts by weight polymer and 24.5 pbw of plasticizer. This is mixed for 2 to 5 minutes under vacuum. Precipitated calcium carbonate is added and mixed for 15 to 20 minutes under vacuum. Methyloximino silane and A-1100 is added to the mixture. Mixing takes place for approximately five minutes under vacuum. The mixture is discharged into tubes for storage and further evaluation. TABLE 2

MECHANICAL PROPERTIES:

FORM.2 FORM.3 FORM.42 FORM.4

EXAM.4 EXAM.5 EXAM.6 EXAM.7

SKIN OVER TIME 77 360-840 50 70

(Minutes) TACKFREE TIME 90 360-840 55 80

(Minutes) TENSILE STRENGTH 1.57 0.27 7.73 1.2

(N/mm2) ELONGATION 280 160 460 250

(%) HARDNESS 40 12 56 37

(SHORE A)

Formulation 5

To 50 parts by weight of the polymer of Example 6 is added 50 parts by weight of a modified cumene-indole resin (softening point, Ring and Ball by ASTM E-28 100°C) at a temperature of between 150 and 200°C. The mixture is prepared as a sheet on polypropylene and allowed to cool. The sheet is allowed to cure for 15 days at room temperature after which it is exposed to 100°C for 6 hours followed by an additional 9 days at room temperature. Tensile properties are as follows: tensile strength - 15 N/mm2; elongation - 790%, hardness (Shore A) -17. Formulation 6

COMPONENT WEIGHT %

Polyether polymer of Example 2 40.00 Di-octyl phthalate 14.50 CaC03 43.00

Methyl tri (2-butanone oxime) silane 2.00 A-1100 0.50

To a double planetary vacuum mixer is added 40 parts by weight polymer and 14.5 pbw of plasticizer. This is mixed for 2 to 5 minutes under vacuum. Precipitated calcium carbonate is added and mixed for 15 to 20 minutes under vacuum. Methyloximino silane and A-1100 is added to the mixture. Mixing takes place for approximately five minutes under vacuum. The mixture is discharged into tubes for storage and further evaluation. Beads of sealant are applied to glass and aluminum substrates and allowed to cure at ambient conditions for 7 days. Adhe¬ sion testing consists of an initial starting razor cut at the substrate adhesive interface. Force is applied at 45° and 90° by hand and the failure mode evaluated visually. Adhesion is ranked on a scale of 1 to 6 with 1 being no adhesion and 6 being cohesive failure at both tensile force angles. The samples are then exposed to boiling water for 15 days and re-tested using the same method. The sample consistently exhibits partial cohesive failure at 45° tensile pull and 100% cohesive failure at 90° pull.

INITIAL BOND 15 DAYS

SAMPLE GLASS ALUMINUM GLASS ALUMINUM

Formulation 6 5 5 5 5 Formulation 7

COMPONENT WEIGHT %

Polyether polymer of example 3 30.00

Di-octyl phthalate 24.50 CaC03 43.00 Methyl tri(2-butanone oxime) silane 2.00

A-1100 0.50

To a double planetary vacuum mixer is added 40 parts by weight polymer and 14.5 pbw of plasticizer. This is mixed for 2 to 5 minutes under vacuum. Precipitated calcium carbonate is added and mixed for 15 to 20 minutes under vacuum. Methyloximino silane and A-1100 are added to the mixture. Mixing takes place for approximately five minutes under vacuum. The mixture is discharged into tubes for storage and further evaluation. The sample is cured for 7 days at room temperature and tensile properties determined by DIN 53504 type s2 and Shore a hardness by ASTM C-661.

Formulation 8

COMPONENT WEIGHT % polymer of Example 1 30.00

Di-octyl phthalate 24.00 CaC03 43.00

Moisture scavenger: Oxzolidine (Angus Chemical) 3.00 3-ethyl-2-methyl-2- (3-methyl butyl) -1,3-oxazolidine

To a double planetary vacuum mixer are added the polymer and di-octyl phthalate. This is mixed for 2 to 5 minutes under vacuum. Precipitated calcium carbonate is added and mixed for 15 to 20 minutes under vacuum. The moisture scavenger is then added to the mixture. Mixing takes place for approximately five minutes under vacuum. The mixture is discharged into tubes for storage and further evaluation. Sealant is produced from each composition and the mechanical properties are measured and listed in Table 3 below.

TABLE 3

Polymer From Formul.6 Formul.7 Formul.8

Example 2 Example 3 Example 1 Skin Over Time 100-150 80-100 300 (Minutes)

Tackfree Time 100-150 80-100 300-1,400 (Minutes)

Tensile Strength 2.3 1.3 2.2 (N/Mm2)

Elongation 440 540 750 (%)

Hardness 41 25 20

(Shore A)

Formulation 9

COMPONENT WEIGHT

Polyether polymer of Example 1 49.50

Di-octyl phthalate 9.90

Precipitated hydrated alumina 24.75

Titanium dioxide 14.85

A-1100 0.99

Solvent component parts per hundred mixture:

Methyl chloroform 40

To 49.5 g of polymer is added 9.9 g of dioctyl phthalate and combined at medium speed with a high shear dispersing blade. To this mixture 24.75 g of alumina trihydrate and 14.85 g of titanium dioxide are combined at medium shear for 5 minutes using a high shear blade. 0.99 g of amino ethoxy silane is added and mixed for 1 minute at medium speed. Approximately 40 parts per hundred of methyl chloroform was added to the mixture to obtain a flowable viscosity. Aluminum sheet cleaned with hexane is coated with the mixture to a uniform thickness. The surface is tack free between 120 and 140 minutes after application. A 1/8 inch thick sheet of coating is prepared by casting the compound in a mold.

Tack free time 120-150 minutes

Tensile strength 3.6 N/mm²

Elongation 260

Shore A hardness 42 Bend Pass - no cracking

EXAMPLE 8 A 1 liter three neck reactor flask fitted with an overhead stirrer, thermometer and addition funnel is charged with 17.5 grams of toluene diisocyanate (0.10M) and heated to 80° to 90°C. Polypropylene oxide diol with average molecular weight of 4000, (200 gm, 0.05M) is added slowly. The reaction mixture is refluxed at 80° to 90°C for 2-4 hours and the progress of the condensation is monitored by infrared spectroscopy. 2-mercaptoethanol (7.8 gm. , 0.10M) is added slowly to the reaction mixture and refluxed at 90° to 100°C until the infrared spectrum of the pot sample shows no isocyanate absorption at 2265 cm^"1. Methylvinyl bis(methylethylketoximino)silane (31.3 gm. , 0.10M) and AIBN (460 mg) are added to the mercapto terminated polyol and refluxed at 85-90°C for 3 hours to give an oximesilane terminated liquid polyol polymer. EXAMPLE 9 Example 8 is repeated except 3-mercaptopropanol (92 g, 0.10M) is used. Similar results are noted.

Formulation 10

COMPONENT WEIGHT %

Polymer of Example 8 or 9 30.00

Di-octyl phthalate 24.50

CaC03 43.00 Methyl tri(2-butanone oxime) silane 2.00

A-1100 0.50

To a double planetary vacuum mixer are added 30 parts by weight polymer and 24.5 pbw of plasticizer. This is mixed for 2 to 5 minutes under vacuum. Precipitated calcium carbonate is added and mixed for 15 to 20 minutes under vacuum. Methyloximino silane and amino propyltrimethoxy silane (Available as A-1110 from Union Carbide) is added to the mixture. Mixing takes place for approximately five minutes under vacuum. The mixture is discharged into tubes for storage and further evaluation with the following results.

Table 4

Example 8 Polymer Example 9 Polymer

Strain at Max. Load 370 270

Maximum Stress 1.3 1.6

Skinover Time 93-106 min. 120-150 min.

Tack free Time 107-116 min. 120-150 min.

Shore A Hardness 30 46

Claims

What is claimed is:

1. An oximinosilane terminated polymer having the formula

R- j -0-C-NH-R¹-NH-C-X-R²-Y-CH2CH2-Si- (0-N-C)_n

(R^J)m

_|P

and having an average molecular weight of at least 1,200; wherein R is an organic polymer having a backbone of polyether, polythioether or polyester, R¹ is a divalent organic radical, R² is an alkylene group having at least 2 carbon atoms, X is 0 or NR⁶ where R⁶ is either hydrogen or a monovalent lower alkyl group, Y is sulfur or S-R⁷-S where R⁷ is an alkylene thioether having 4-12 carbon atoms, alkylene having 2 to 10 carbon atoms, or a substituted cyclohexyl ring group having the formula:

/ \ / \

CH₂ CH-CH₂-CH₂- or CH₂ CH-

\ \ /

CH CH

CH

/ \ CH₃ CH₂- R³ is an alkyl radical of 1 to 7 carbon atoms or an alkoxy radical of 1 to 6 carbon atoms and R⁴ and R⁵ are independently a saturated straight chain or branched alkyl radical of 1 to 7 carbon atoms or R⁴ and R⁵ taken together form a cyclized group, p is 2 to 3, m is 0 to 2, n is 1 to 3 and the sum of m and n is 3.

2. The oximinosilane terminated polymer of claim 1 wherein R is hydroxyl terminated polymer selected from the group consisting of polypropylene oxide polyols, polybutyleneoxide glycol polyols, polytetramethylene glycol polyols, polyester polyols, polythioether polyols, polyalkylene glycol co-polymer polyols, and polyalkylene glycol-polyester copolymer polyols.

3. The oximinosilane terminated polymer of claim 1 which is a liquid having a molecular weight in the range of from about 1,200 to about 100,000.

4. A composition comprising: a.) the oximinosilane terminated polymer of claim 1 in an amount of from about 5% to about 90% by weight of the composition; and b.) a moisture scavenger in an amount of from 0% to about 5% by weight of the composition; and c.) a plasticizer in an amount of from 0% to about 50% by weight of the composition; and d.) a filler in an amount of from 0% to about 75% by weight of the composition.

5. A method for the production of oximinosilane terminated polymers having the formula

R⁴ I R- I -0-C-NH-R¹-NH-C-X-R²-Y-CH2CH2-Si- (0-N=C)_n

II

0 (R^J)m R-

_IP

and having an average molecular weight of at least 1,200; wherein R is an organic liquid polymer containing a backbone of polyether, polythioether or polyester, R¹ is a divalent organic radical, R² is an alkylene group having at least 3 carbon atoms, X is 0 or NR⁶ where R⁶ is either hydrogen or a monovalent lower alkyl group, Y is sulfur or S-R⁷-S where R⁷ is an alkylene thioether having 4-12 carbon atoms, alkylene having 2 to 10 carbon atoms, or a substituted cyclohexyl ring group having the formula:

CH-.

CH₂ CH

/ \ / \

CH₂ CH-CH₂-CH₂- or CH₂ CH-

CH₂ CH- CH- CH- \ \ /

/ \

CH CH- ^• R³ is an alkyl radical of 1 to 7 carbon atoms or an alkoxy radical of 1 to 6 carbon atoms and R⁴ and R⁵ are independently a saturated straight chain or branched alkyl radical of 1 to 7 carbon atoms or R⁴ and R⁵ taken together form a cyclized group, p is 2 to 3, m is 0 to 2, n is 1 to 3 and the sum of m and n is 3; the method comprising: a.) reacting an isocyanate terminated polymer having the general formula:

R[0-C-NH-R¹-N=C=0].

with an olefin alcohol or amine in which the olefin group is separated by at least one carbon atom to give olefin terminated polyether polyol; b.) reacting the olefin-terminated polymer with a dimercaptan in which the mercaptan functionality is separated by an alkylene, alkylene ether, alkylene thioether, alkylene ester or substituted cyclohexyl rings to give a mercaptan-terminated polymer; and c.) reacting the mercaptan terminated polymer with a component selected from the group consisting of vinyl oximino silane, vinylalkyloximino silane, vinylaryloximino silane, vinylalkylalkoxyoximino silane vinylalkoxyoximino silane and vinylarylalkoxyoximino silane.

6. The method of claim 5 wherein R is a hydroxyl terminated polymer selected from the group consisting of polypropylene oxide polyols, polybutyleneoxide glycol polyols, polytetramethylene glycol polyols, polyester polyols, polythioether polyols, polyalkylene glycol co- polymer polyols, and polyalkylene glycol-polyester copolymer polyols.

7. The method of claim 5 wherein the dimercaptans are selected from the group consisting of 1,2-ethane dithiol, 1,6-hexane dithiol, 1,10-decane dithiol, 2-mercaptoethylether, 2-mercaptoethylsulfide, glycol dimercapto acetate, glycol dimercapto propionate, p- menthane-2,9-dithiol, ethylene bis (3-mercapto propionate) and ethylcyclohexane dithiol.

8. The method of claim 5 wherein the vinyloximino silane or vinylalkoxyoximino silane has the formula,

R⁴

H2C=CH-Si- (0-N=C)_n

I I (R³)m R₅

9. A method for the production of oximinosilane terminated polymers having the formula R- j - 0- C-NH-R¹ -NH- C-X-R² -Y- CH2CH2 - Si - (0-N=C) _n

II

0 (R^J ) m R-

_ | P

and having an average molecular weight of at least 1,200; wherein R is an organic liquid polymer having a backbone of polyether, polythioether or polyester, R¹ is a divalent organic radical, R² is an alkylene group having at least 2 carbon atoms, X is 0 or NR⁶ where R⁶ is either hydrogen or a monovalent lower alkyl group, Y is sulfur or S-R 7-S where R π' i.s an alkylene thi.oether having 4-12 carbon atoms, alkylene having 2 to 10 carbon atoms, or a substituted cyclohexyl ring group having the formula:

CH₃

CH₂ CH

/ \ / \

CH₂ CH-CH₂-CH₂- or CH₂ CH-

CH₂ CH- CH- CH- \ \ /

/ \

CH₃ CH₂•

R³ is an alkyl radical of 1 to 7 carbon atoms or an alkoxy radical of 1 to 6 carbon atoms and R⁴ and R⁵ are independently a saturated straight chain or branched alkyl radical of 1 to 7 carbon atoms or R⁴ and R⁵ taken together form a cyclized group, p is 2 to 3, m is 0 to 2, n is 1 to 3 and the sum of m and n is 3; the method comprising:

a.) reacting an isocyanate terminated polymer having the general formula:

R[0-C-NH-R¹-N=C=0].

0

with a mercapto alcohol in which the mercaptan and the hydroxyl groups are separated by at least two methylene groups to produce a mercaptan terminated polymer; and b.) reacting the mercaptan terminated polymer with a component selected from the group consisting of vinyl oximino silane, vinylalkyloximi.no silane, vinylaryloximino silane, vinylalkylalkoxyoximino silane vinylalkoxyoximino silane and vinylarylalkoxyoximino silane.

10. The method of claim 9 wherein R is a hydroxyl terminated polymer selected from the group consisting of polypropylene oxide polyols, polybutyleneoxide glycol polyols, polytetramethylene glycol polyols, polyester polyols, polythioether polyols, polyalkylene glycol co- polymer polyols, and polyalkylene glycol-polyester copolymer polyols.