CA2034164A1 - Sprayable and pourable polyurea elastomer - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A pourable and/or sprayable polyurea elastomer is disclosed. The elastomer includes an isocyanate, an amine terminated polyoxyalkylene polyol, and a chain extender. The isocyanate is preferably a quasi-prepolymer of an isocyanate and a material selected from at least one polyol, a high molecular weight polyoxyalkyleneamine or a combination thereof.
The chain extender includes at least N,N'-bis(t-butyl)ethylene-diamine. A method for improving the flowability of a polyurea elastomer, thereby permitting the elastomer to be sprayed or, optionally, poured, is also disclosed.

Description

. ~ 203~

SPRAYA8LE AND POIJRABLE POLY~ EI~STOMER
(D#80, 825 -F) !; BACRGROIJND OF l~E INVEN'rION

1. Field of the Invention The present invention relates to sprayable and pourable polyurea elastomers which include novel chain extenders.

2. Descri~tion of Back~round Art Elastomer systems are commonly recognized as, among other things, coating materials, with spray polyurea elastomer systems being particularly useful when employed in this capa-city. One of the considerations confronting the skilled artisan is the sprayability of the elastomer during the critical period, that is, the point at which the reactive components are combined up through the point at which gelation occurs. Similarly, the pourability of the elastomer during the critical period also concerns the skilled artisan where the elastomer is to be poured into an open mold, such as in electric potting type work.
Polyurea elastomer systems are generally prepared by reacting an isocyanate with an active hydrogen component in the presence of a chain extender. Certain known chain extenders react very rapidly with the isocyanate component and, therefore, are not well suited for spray or pour systems, inasmuch as poly-merization or gelation occurs so rapidly that the elastomer is virtually unsprayable and unpourable. One of the most widely employed chain extenders is diethyltoluene diamine (DETDA), a product of Ethyl Corporation. Polyurea elastomer systems fabricated from, among other things, DETDA generally exhibit good processing characteristics.

pr\dgvo2 -1-,, '. . ': '' ': ' . ' ' '' ~ . ' : ' : :

203~164 However, one of the shortcomings associated with elastomer systems fabricated with DETDA, where sprayable and/or pourability are at issue, is the rapid gelation time. The polyurea elastomer system of the present invention includes a chain extender that reacts slower with the isocyanate component and, accordingly, the rate at which the elastomer will gel is reduced resulting in improved flowability, thereby permitting the elastomer to be sprayed and/or poured. In addition, the polyurea elastomer system of the present invent:ion exhibits certain properties which are similar to or better than those exhibited by systems fabricated from DETDA.

U.S. Patent No. 3,979,364 describes the use of aminated polyethers as hereinafter used as a component with a polyol to 15 make an elastomer. U.S. Patent No. 3,666,788 describes the use of cyanoalkylated aminated polyethers in spray systems. The '788 disclosure, in Column 1, states that the aminated polyethers as used hereinafter cannot be used in spray coatings due to very rapid reaction rates with isocyanates.
U.S. Patent Nos. 4,379,729; 4,444,910; and 4,433,067 describe elastomers which are prepared using a high molecular weight amine terminated polyether, an aromatic diamine chain extender and an aromatic polyisocyanate which may merely be a polyisocyanate or a quasi-prepolymer prepared from a polyol reacted with a polyisocyanate wherein some isocyanate groups are still left unreacted. Various patents have been applied for and received using the basic combination recited above as well as various mold release agents and other additives, such as catalysts and fillers, inc}uding glass fibers. For example, see U.S. Patent No. 4,607,090.

U.S. Patent No. 3,714,128 describes cyanoalkylated polyoxyalkylene polyamines which are useful for slowing the gelling or hardening of the polyurea component so that good , pr\d~vO2 -2-.

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~ ~3 3 r mixing of the isocyanate and amine components can be attained, which gives the sprayed material ample time to adhere and level before gelation of ~he polyurea coating occurs. This patent does not describe the particular chain extenders employed in the elastomer of the present invention.

U.S. Patent No. 4,714,778 describes certain alkenylated toluene diamines which are reported as being useful as tri- and tetrafunctional chain extenders for forming polyurethane-urea 10 elastomers.

U.S. Patent No. 4,~16,543 describes a monotertiary-alkyltoluene diamine which is reported as being useful as a chain extending agent for the formation of polyurethane-urea elastomers. At least 50% of the equivalent weight of the chain extending agent is mono-tertiary-butyltoluene diamine.

U.S. Patent No. 4,806,615 describes reaction injection molded (RIM) elastomers consisting of a cured reaction product of primary or secondary amine terminated polyethers of greater than 1500 molecular weight, an aromatic polyisocyanate, a combination of an unsubstituted aromatic diamine chain extender and a substituted acyclic aliphatic diamine chain extender.

U.S. Patent No. 4,218,543 describes the use of high molecular weight polyols, certain aromatic diamines and isocyanates for the production of RIM parts. This patent specifically claims as a chain extender 1-methyl-3,5-diethyl-2,4-diaminobenzene (diethyltoluenediamine) and its isomer.
U.S. Patent No. 4,523,004 discloses a substituted aromatic diamine chain extender in a RIM product.

U.S. Patent No. 4,631,298 discloses blending various slower reacting chain extenders with diethyltoluene diamine in a RIM system using amine terminated polyethers.

pr\dgvO2 -3-.

~3~

Thus, it is our understanding that a polyurea elastomer system which incorporates the particular chain extenders de-scribed hereinbelow and which is sprayable and/or pourable hasheretofore been unavailable.
SUMM~RY OF THE INVENTION

Accordingly, the present invention relates to a polyurea elastomer which comprises an (A) component and a (B) component. The ~A) component includes an isocyanate. Prefer-ably, the isocyanate of component (A) i~cludes a quasi-prepoly-mer of an isocyanate and a material selected from at least one polyol, a high molecular weight polyoxyalkyleneamine or a combination of these materials. The (B) component includes (1) an amine terminated polyoxyalkylene polyol and (2) a chain extender which includes at least N,N'-bis(t-butyl)ethylenediamine Preferably, the chain extender includes a combination of N,N'-bis (t-butyl)ethylenediamine and diethyltoluene diamine (DETDA).

The present invention also relates to a method for improving the flowability of a polyurea elastomer thereby permit-ting said elastomer to be sprayed or, optionally, poured. Speci-fically, the present method comprises incorporating a chain extender including at least N,N'-bis(t-butyl)ethylenediamine into the elastomer. The N,N'-bis(t-butyl)ethylenediamine is employed in an amount sufficient to reduce the time in which the elastomer will gel, thereby improving the flowability of the elastomer. A
first and second reactive stream are directed into mutual contact with each other to effectuate a mixing of the first and second reactive streams. The first reactive stream includes an isocyanate and the second reactive stream includes an amine terminated polyoxyalkylene polyol and the aforedescribed chain extender. The mixed first and second reactive streams are sprayed or, optionally, poured onto or, optionally, into a substrate.

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Advantageously, when ~he chain extenders disclosed herein are used to prepare the elastomer of the present inven-tion, the rate at which gelation will occur is reduced resultingin improved flowability, thereby permitting the elastomer to be sprayed during the aforestated critical period. The reduced reactivity and resulting improved flowability also permits the present elastomer to be used in a pour gun for electrical potting work and small mold filling work. In addition to satisfying the criteria of sprayability and/or pourability, the present elastomer also exhibits improved elongation and spray surface quality, as well as good processability, appearance and toughness.

DESCRIPTION OF T~E PREFERRED EMBODIMENTS

The isocyanates employed in component (A) are those known to one skilled in the art. Thus, for instance, they can include aliphatic isocyanates of the type described in U.S.
Patent No. 4,748,192. Accordingly, they are typically aliphatic diisocyanates, and, more particularly, are the trimerized or the biuretic form of an aliphatic diisocyanate, such as hexamethylene diisocyanate, or the bifunctional monomer of the tetraalkyl xylene diisocyanate, such as the tetramethyl xylene diisocyanate.
Cyclohexane diisocyanate is also to be considered a preferred aliphatic isocyanate. Other useful aliphatic polyisocyanates are 25 described in U.S. Patent No. 4~705,814. They include aliphatic diisocyanates, for example, alkylene diisocyanates with 4 to 12 carbon atoms in the alkylene radical, such as 1,12-dodecane diisocyanate and 1,4-tetramethylené diisocyanate. Also described are cycloaliphatic diisocyanates, such as 1,3 and 1,4-cyclohexane diisocyanate as well as any desired mixture of these isomers, l-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane ~isophorone diisocyanate); 4,4'-,2,2'- and 2,4'-dicyclohexylme-thane diisocyanate as well as the corresponding isomer mixtures, and the like.

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.
A wide variety of aromatic polyisocyanates may be used to form the elastomer of the present invention. Typical aromatic polyisocyanates include p-phenylene diisocyanate, polymethylene polyphenylisocyanate, 2,6-toluene diisocyanate, dianisidine diisocyanate, bitolylene diisocyanate, naphthalene-1,4-diisocy-anate, bis(4-isocyanatophenyl)methane, bis(3-methyl-3-isocyan-atophenyl)methane, bis~3-methyl-4-isocyanatophenyl)-methane, and 4,4'-diphenylpropane diisocyanate.

Other aromatic polyisocyanates used in the practice of the invention are methylena-bridged polyphenyl polyisocyanate mixtures ~hich have a functionality of from about 2 to about 4.
These latter isocyanate compounds are generally produced by the phosgenatio~ of corresponding methylene bridged polyphenyl polyamines, which are conventionally produced by the reaction of formaldehyde and primary aromatic amines, such as aniline, in the presence of hydrochloric acid and/or other acidic catalysts.
Known processes for preparing polyamines and corresponding methylene-bridged polyphenyl polyisocyanates there~`rom are described in the literature and in many patents, for example, U.S. Patent Nos. 2,683,730; 2,950,263; 3,012,008; 3,344,162: and 3,362,979.

Usually methylene-bridged polyphenyl polyisocyanate 25 mixtures contain about 20 to about 100 weight percent methylene diphenyldiisocyanate isomers, with the rPmainder being poIyme-thylene polyphenyl diisocyanates having higher functionalities and higher molecular weights. Typical of these are polyphenyl polyisocyanate mixtures containing about 20 to 100 weight percent'diphenyldiisocyanate isomers, of which 20 to about 95 weight percent thereof is the 4,4'-isomer with the remainder being polymethylene polyphenyl polisocyanates of higher molecu-lar weight and funtionality that have an average functionality of from about 2.1 to about 3.5. These isocyanate mixtures are known, commercially available material's and can be prepared, for instance, by the process described in U.S. Patent No. 3j362,979.

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By far the most preferred aromatic polyisocyanate is methylene bis(4-phenylisocyanate) or MDI. Pure MDI, quasi-prepolymers of M~I, modified pure MDI, etc. are useful.Materials of this type may be used to prepare suitable RIM
elastomers. Since pure MDI is a solid and, thus, often incon-venient to use, liquid products based on MDI or methylene bis(4-phenylisocyanate) are used herein. U.S. Patent No.
3,394,164 describes a liquid MDI product. More generally, uretonimine modified pure MDI is included also. This product is made by heating pure distilled MDI in the presence of a catalyst.
The liquid product is a mixture of pure MDI and modified MDI and is represented as follows:

2[OCN ~ CH2 ~ -NCO]
Catalyst OCN ~ CH2 ~ N- C=N ~ CH2 ~ -NCO + CO2 Carbodiimide C~ 2 (~\ t I N C~ ) CH2 ~ NCO

O=C-N ~ CH2 ~ NCO
Uretonimine Examples of commercial materials of this type are Dow's ISONATE~
125M (pure MDI) and ISONATE 143L ("liquid" MDI). Preferably the amount of isocyanates used is the stoichiometric amount based on all the ingredients in the formulation or greater than the stoichiometric amount.
.:
of course, the term isocyanate also includes quasi-prepolymers of isocyanates or polyisocyanates with active hydrogen containing materials. The active hydrogen containing materials can include, but are not limited to, a polyol or pr\dgvO2 ~7~

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.. . ., .~ ~ . . : ,~ .

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polyo}s, a high molecular wei~ht polyoxyalkyleneamine or combinations thereof.

The polyols include polyether polyols, polyester dioIs, triols, tetrols, etc., having an equivalent weight of at least about 500, and preferably at least about 1,000 up to about 3,000.
Those polyether polyols based on trihydric initiators of about 4,000 molecular weight and a~ove are especially preferred. The polyethers may be prepared from ethylene oxide, propylene oxide, butylene oxide or mixtures of propylene oxide, butylene oxide and/or ethylene oxide. Other high molecular weight polyoIs which may be useful in this invention are polyesters of hydroxyl terminated rubbers, e.g., hydroxyl terminated polybutadiene.
Hydroxyl terminated quasi-prepolymers of polyols and isocyanates are also useful in this invention.

Especially pre~erred are amine terminated polyether polyols, including primary and secondary amine terminated poly-ether polyols of greater than 1,500 average molecular weight20 having from about 2 to about 6 functionality, preferably from about 2 to about 3, and an amine equivalent weight of from about 750 to about 4,000. Mixtures of amine terminated polyethers may be used. In a preferred embodiment the amine terminated poly-ethers have an average molecular weight of at least about 2,500.
These materials may be made by various methods known in the art.

The amine terminated polyether resins useful in thisinvention, for example, are polyether resins made from an appropriate initiator to which lower alkylene oxides, such as ethylene oxide, propylene oxide, butylene oxide or mixtures thereof, are added with the resulting hydroxyl terminated polyol then being aminated.

When two or more oxides are used, they may be present as random mixtures or as blocks of one or the other polyether.
In the amination step it is highly desirable that the terminal pr\dgvo2 -8-::: : .
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hydroxyl groups in the polyol be essentially all secondary hydroxyl groups for ease of amination. Normally, the amination step does not completely replace all of the hydroxyl groups.
However, the majority o~ hydroxyl groups are replaced by amine groups. Therefore, in a preferred embodiment, the amine termin-ated polyether resins useful in this invention have greater than percen~ of their activ~ hydrogens in the form of amine hydrogens. If ethylene oxide is used it is desirable to cap the hydroxyl terminated polyol with a small amount of higher alkylene oxide to ensure that the terminal hydroxyl groups are essentially all secondary hydroxyl groups. The polyols so prepared are then reductively aminated by known technic~es, for example, as described in U.S. Patent No. 3,654,370, the contents of which is incorporated herein b~ reference.

In the practice of this invention, a single high molecular weight amine terminated polyol may be used. Also, mixtures of high molecular weight amine terminated polyols, such as mixtures o~ di-and trifunctional materials and/or different molecular weight or different chemical composition materials, may be used.

Also, high molecular weight amine terminated polyethers or simply polyether amines are included within the scope of our invention and may be used alone or in combination with the afore-stated polyols. The term high molecular weight is intended to include polyether amines having a molecular weight of at least about 2000. Particularly preferred are the JEFFAMINE~ series of polyether amines available from Texaco Chemical Company; they 30 include ~EFFAMINE D-2000, JEFFAMINE D-4000, JEFFAMINE T-3000 and JEFFAMINE T-5000. These polyether amines are described with particularity in Texaco Chemical Company's product brochure entitled THE JEFFAMINE POLYOXYALKYLENEAMINES.

The (B) component of the present polyurea elastomer system includes an amine terminated polyoxyalkylene polyol and a chain extender. The amine terminated polyoxyalkylene polyol pr\dgvO2 ~9~

-. .

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is preferably sel~cted from diols or triols and, most preferably, includes a blend of diols and/or triols. The particular polyols, i.e., diols and/or triols, employed in component ~B) are the same as those described hereinabove in connection with the quasi-pre-polymer of component (A).

The chain extenders useful in this invention include N,N'-bis(t-butyl) ethylenediamine, either used alone or, in a preferred embodiment, in combination with, l-methyl-3,5-diethyl-2,4-diaminobenzene or 1 methyl-3,5-diethyl-2,6-diaminobenzene (both o~ these materials are also called diethyltoluene diamine or DETDA). The N,N'-bis(t-butyl)ethylenediamine component is commercially available from Virginia Chemicals, Portsmouth Virginia. The preferred chain extender includes from about 20 to about 99 parts of N,N'-bis(t-butyl)ethylenediamine to about 80 to about 1 parts of DETDA. ;~

Advantageously, the (A) and (B) components react to form the present elastomer system without the aid of a cata-lyst. However, if desired, a catalyst can be used.

Catalysts such as tertiary amines or an organic tin compound may suitably be a stannous or stannic compound, such -as a stannous salt of a carboxylic acid, a trialkyltin oxide, a dialkyltin dihalide, a dialkyltin oxide, etc., wherein the organic groups o~ the organic portion of the tin compound are hydrocarbon groups containing from 1 to 8 carbon atoms. For example, dibutyltin dilaurate, dibutyltin diacetate, diethyltin diacetate, dihexyltin diacetate, di-2-ethylhexyltin oxide, dioctyltin dioxide, stannous octoate, stannous oleate, etc., or a mixture thereof, may be used.

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Tertiary amine catalysts include trialkylamines (e.g., trimethylamine, triethylamine); heterocyclic amines, such as N-alkymorpholines (e.g., N-me~hylmorpholine, N-ethylmorpholine, dimethyldiaminodiethylether, etc.), 1,4-dimethylpiperazine, trie-thylenediamine, etc.: and aliphat~c polyamines, such as N,N,N'N'tetramethyl-1,3-butanediamine.

Other conventional fomulation ingredients may be employed in component (A) or (B) as needed, such as, for example, foam stabilizers, also known as silicone oils or emulsifiers. The foam stabilizers may be an organic silane or siloxane. For example, compounds may be used having the formula:

RSi[O-(R2SiO)n~(oxyalkylene~mR]

wherein R is an alkyl group containing from 1 to 4 carbon atoms; n is an integer of from 4 to 8; m is an integer of from 20 to ~0: and the oxyalkylene groups are derived from propylene oxide and ethylene oxide. See, for example, U.S. Patent No.
3,194,773.

Pigments, for example titanium dioxide, may be incorporated in the elastomer system, preferably in the (B) component, to impart color properties to the elastomer.

Post curing of the elaskomer of the invention is optional. Post curing will improve some elastomeric proper-ties, such as heat sag. Employment of post curing depends onthe desired properties of the end product.

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The (A) component and (B) component of the present polyurea elastomer system are combined or mixed under high pressure; most preferably, they are impingement mixed directly in the high pressure equipment, which is, for example, a GUSMER~
H-V proportioner fitted, for instance, with a GUSMER Model GX-7 spray gun. In particular, a first and second pressurized stream of components (A) and (B), respectively, are delivered from two separate chambers of the proportioner and are impacted or impinged upon each other at high velocity to effectuate an }O intimate mixing of the two components and, thus, the formation of the elastomer system, which is then coated onto the desired substrate via the spray gun.

As stated above, the polyurea elastomer of the present invention can also be used in a pour gun for electric potting type work or other open mold work that involves pouring. When used in this capacity, the (A) and (B) components are mixed in the same manner as described above. However, the high pressure spray equipment is fitted with a pour g-ln, such as a GUS~IER model AR-C pour gun, instead of a spray gun.

Whether the elastomer of the present invention is to be sprayed or poured, the volumetric ratio of the (A) component to the (B) component is generally from about 30 to 70 percent to about 70 to 30 percent. Preferably, component (A~ and component (B) are employed in a 1:1 volumetric ratio.

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GLOSSARY OF TERMS AND MATERIALS

ISONATE~ 143 L - Carbodiimide modified liquid MDI; a product of the Dow Chemical Company.
THANOL~ SF-5505 - A 5500 molecular weight: polyether triol containing approximately 80% primary hydroxide groups; a product of ARCO Chemical Company.
JEFFAMINE~ T-5000 - Polypropylene oxide triamine of about 5000 molecular weight; a product of Texaco Chemical Company.
~ .
15 JEFFAMINE~ T-3000 - Polypropylene oxide triamine of about 3000 molecular weight; a product of Texaco ;
Chemical Company.

JEFFAMINE~ D-4000 - Polypropylene oxide diamine of about 4000 molecular weight; a product of Texaco Chemical Company.

JEFFAMINE~ D-2000 - Polypropylene oxide diamine of about 2000 molecular weight; a product of Texaco Chemical Company.
-,:
The following examples are provided to further illustrate preferred embodiments of the present invention and should not be construed as limiting the present invention in any way.

pr\dgvO2 -13-, , . , .,- . . . . , . . ~- .,- ~ : ~ - .

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" ~

In the examples, all spray work was performed with a GUSMER H-V high pressure proportioner fitted with a GUSMER model GX-7 spray gun or a GUSMER model AR-C pour gun, where appro-priate. The elastomer systems were sprayed and poured using a block temperature of 160~F on the (A) component side and 150F to 160-F on the (B) component side, with a hose temperature of 160F. The system output ranged from 17.5 lbs/min to 22.5 lbs/min with a line pressure ranging from 1400 to 2800 psig on the (A) component side and (B) component side. Each of the elastomer systems produced in the examples were mixed at an (A):(B) volumetric ratio of 1:1.

EXAMPLE I

The (A) component of a polyurea elastomer was prepared by combining 60 parts of ISONATE 143L and 40 parts of THANOL SF-5505 to form a quasi-prepolymer. The (B) component was prepared by combining 65.5 parts of JEFFAMINE D-4000, 24.5 parts of DETDA and 10 parts of N,N'-bis(t-butyl)ethylenediamine.
The (A) and (B) components were mixed in the high pressure equipment, which was fitted with a spray~ gun. The resulting elastomer was sprayed onto a flat metal substrate coated with a zinc stearate based external mold release agent.

COMPARATIVE EXAMPLE I tA) The (A) component of the polyurea elastomer produced in this example was prepared in accordance with Example I. The (B) component was prepared by combining 65.5 parts of JEFFAMINE
D-4000 with 34.5 parts of DETDA. The resulting elastomer was mixed and sprayed in accordance with Example I.

pr\dgvO2 -14-. , . . . . :: : - : . :- . - ::.
. : , .. ,. : : . .. ~, : ::
:: ~ :. . ,. ~ : : : , . . .
:: . :.. .. - : ,.,: ,,,, , : . : . , .' . ~ , , ' ' ' ', ' ' " ' `

~` 2~3~

The gel times of the polyurea elastomers produced in Example I and Comparative Example I(A) were 2.5 and 2.0 seconds, respectively. Thus, these examples demonstrate that the elastomer of the present invention exhibits a slower gel time relative to an elastomer that is devoid of the chain extenders described herein. Also, a physical inspection of the elastomers produced in Example I and Comparative Example I(A) shows that the elastomer prodl~ced in Example I exhibits improved flexibility when compared with the elastomer produced in Comparative Example I(A).

EXAMPLE II
.
The (A) component of the polyurea elastomer produced in this example was prepared in accordance with Example I. The (B) component was prepared by combininy 65.3 parts of JEFFAMINE
D-4000, 25.6 parts of DETDA and 9.1 parts of N,N'-bis(t-butyl) ethylenediamine. The tA) and (B) components were mixed in the high pressure equipment, which was fitted with a spray yun. The resulting elastomer was sprayed in accordance with Example I and Comparative Example I(A). The gel time was 2.5 seconds. Thus, it is again demonstrated that the elastomer of the present invention exhibits a slower gel time that the elastomer produced in Comparative Example I(A).

EXAMPLE III

The (A) and (B) components of the polyurea elastomer produced in this example were prepared in accordance with Example II. In this example, however, the high pressure proportioner was fitted with a pour gun instead of a spray gun. The resulting elastomer was poured into and filled a 10" x 10" x 0.125" metal mold.

pr\dgvo2 -15-2~3~

COMPARATIVE EXAMPLE I I I ( A ) The (A) component of the polyurea elastomer produced in this example was prepared in accordance with Example I. The (B) component was prepared by combining 65.8 par~s of JEFFAMINE
D-4000 with 34.2 parts of DETDA. The elastomer produced in this example was mixed and poured in accordance with Example III.

The physical properties of the polyurea elastomers produced in Example III and Comparative Example III(A) were analyzed; the results as well as the respective gel times are reported in Table II.

TABLE I

COMPARATIVE
PROPERTIES EX~PLE III EXAMP~E III(A) Gel Time (sec.) 2.2 1.5 20 Tensile (psi) 3198 3402 Elongation ~%) 370 280 Tear (pli) 602 ~39 Shore D hardness (0 sec.) 60 66 (10 sec.) 54 60 25 Flexural Modulus (psi) 66851 63679 (77F) These data further establish the reduced gel time exhibited by the polyurea elastomer of the present invention.
These data also establish the superiority of certain other properties. Additionally, as the molds were being filled with the elastomers produced in Example III and Comparative Example III(A), visual inspection revealed better flowability with the elastomer of Example III. Improved flowability is further pr\dgvo2 -16-.~ . ~ .. . .. . . .. . .... . .. , . : ~, ...

: :i-:, i:: -: . ~ . ~. . -:: . :,.:. , ~ ~ 3 ~
"~

demonstrated by the fact that the elastomer of Example III gave no mix lines after the mold was 100% full, while the elastomer of Comparative Example III(A) did exhibit mix lines with a less than 95% mold fill.
:
EXAMP~E IV

The (A) component if the polyurea elastomer produced in this example was prepared in accordance with Example I. The (B) component was prepared by combining 66.2 parts of JEFFAMINE
T-5000, 24.3 parts of DETDA and 9.5 parts of N,N'-bis(t-butyl) ethylenediamine. The (A) and (B) components were mixed in the high pressure spray equipment and the resulting elastomer was ,~:~
sprayed onto a flat metal substrate coated with a zinc stearate based external mold release agent.
.
COMPARATIVE EXAMPLE IV(A) The (A) component of the polyurea elastomer produced in this example was prepared in accordance with Example I. The (B) component was prepared by combining 66 parts of JEFFAMINE T-5000 and 34 parts of DETDA. The (A) and (B) components were mixed and sprayed as in Example IV.
The physical properties of the polyurea elastomers produced in Example IV and Comparative Example IV(A) were analyzed; the results as welI as the respectve gel times are reported in Table II.
.

pr\dgvO2 -17-2~3~
, TABLE II

COMPARATIVE
PROPERTIES EXAMPLE IV EXAMPLE IV (A) Gel Time (sec.) 2.5 1.5 Tensile (psi) 1746 1918 Elongation (%) 143 117 Tear (pli) 385 403 Shore D hardness(0 sec.) 41 50 (10 sec.)37 47 Flexural Modulus ~psi) (77F) 41543 42900 (158F) 33478 36822 (-20F) 73988 83241 Heat sag (mm) 100 mm -250F~60 min 2.0 0.3 150 mm -311~F/60 min 15.1 1.9 As these data demonstrate, the polyurea elastomer of the present invention ~Example IV) exhibits a gel time that is far slower than that exhibited by an elastomer which is devoid of the chain extenders described herein (Comparative Example IV(A)).
The elastomer of the present invention also exhibits improved elongation.

EXAMPLE V

The (A) component of the polyurea elastomer produced in this example was prepared in accordance with Example I. The (B) component was prepared by combining 30.9 part5 of JEFFAMINE
T-5000, 34.6 parts of JEFF~INE D-4000, 25.4 parts of DETDA, 8.7 parts of N,N'-bis(t-butyl)ethylenediamine and 0.4 parts of a silicone surfactant. The (A) and (B) components were ~ixed and sprayed in accordance with Example IV.

pr\dgvO2 -18-:: . : :~ ,: , ~ . . . ..

. .
, 2 ~ 3 ~

COMPARATIVE EXAMPLE V(A) The (A) component of the polyurea elastomer produced in this example was prepared in accordance with Example I. The (B) component was prepared by combining 16.4 parts of JEFFAMINE
T-5000, 49.2 parts of JEFFAMINE D-4000 ancl 34.4 parts of DETDA.
The (A) and (B) components were m.ixed and sprayed in accordance .:.
with Example IV.

The ~el times of the elastomers produced in Example V
and Comparative V(A) were 2.5 and 1.5 seconds, respectively.

~:

', . . ' pr\dgvO2 -19-'.:

Claims (16)

1. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows;
   
   l. A polyurea elastomer comprising an (A) component which includes an isocyanate and a (B) component which includes (1) an amine terminated polyoxyalkylene polyol and (2) a chain extender, said chain extender including at least N,N'-bis(t-butyl) ethylenediamine.
2. 2. The elastomer of Claim 1 wherein said isocyanate of component (A) comprises a quasi-prepolymer of said isocya-nate and a material selected from at least one polyol, a high molecular weight polyoxyalkyleneamine or a combination of said materials.
3. 3. The elastomer of Claim 2 wherein said at least one polyol of said quasi-prepolymer and said amine terminated polyoxyalkylene polyol of component (B) comprise polyether polyols or polyester polyols having an equivalent weight of at least about 500.
4. 4. The elastomer of Claim 3 wherein said polyester polyols are polyesters of hydroxyl terminated rubbers.
5. 5. The elastomer of Claim 3 wherein said polyether polyols are selected from the group consisting of polyols based on trihydric initiators having a molecular weight of at least about 4000; amine terminated polyether polyols having an average molecular weight greater than 1500, a functionality of from about 2 to about 6 and an amine equivalent weight of from about 750 to about 4000; and mixtures thereof.
6. 6. The elastomer of Claim 5 wherein the functiona-lity of said polyether polyols is from about 2 to about 3.
7. 7. The elastomer of Claim 3 wherein said polyether polyols are derived from amine terminated polyether resins having greater than so percent of their active hydrogens in the form of amine hydrogens.
8. 8. The elastomer of Claim 3 wherein said amine terminated polyoxyalkylene polyol of component (B) is selected from diols, triols or blends thereof.
9. 9. The elastomer of Claim 1 wherein said chain extender further comprises diethyltoluene diamine.
10. 10. The elastomer of Claim 9 wherein said chain extender comprises from about 20 to about 99 parts of N,N'-bis (t-butyl)ethylenediamine to about 80 to about 1 parts of diethyltoluene diamine.
11. 11. The elastomer of Claim 1 wherein the volumetric ratio of the (A) component to the (B) component is from about 30 to about 70 percent of the (A) component to about 70 to about 30 percent of the (B) component.
12. 12. A polyurea elastomer comprising an (A) component which includes a quasi-prepolymer of an isocyanate and a material selected from at least one polyol, a high molecular weight polyoxyalkyleneamine or a combination of said materials; and a (B) component which includes (1) an amine terminated polyoxalkylene polyol and (2) a chain extender including a blend of N,N'-bis(t-butyl)ethylenediamine and diethyltoluene diamine.
13. 13. The elastomer of Claim 12 wherein said chain extender includes from about 20 to about 99 parts of N,N'-bis (t-butyl)ethylenediamine to about 80 to about 1 parts of diethyltoluene diamine.
14. 14. A method for improving the flowability of a polyurea elastomer, thereby permitting said elastomer to be sprayed or, optionally, poured, said method comprising incorporating a chain extender including at least N,N'-bis (t-butyl)ethylenediamine into said elastomer in an amount suficient to reduce the time in which said elastomer will gel, thereby improving the flowability of said elastomer directing a first and second reactive stream into mutual contact with each other to effectuate a mixing of said first and second reactive streams, said first reactive stream including an amine terminated polyoxyalkylene polyol and said chain extender; and spraying or, optionally, pouring said mixed first and second reactive streams onto or, optionally, into a substrate.
15. 15. The method of Claim 14 wherein said chain extender further comprises diethyltoluene diamine.
16. 16. The method of Claim 15 wherein said chain extender comprises from about 20 to about 99 parts of N,N'-bis(t-butyl) ethylenediamine to about 80 to about 1 parts of diethyltoluene diamine.