JPH0134527B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of polyurethane-ureas using alkylated aromatic diamines as crosslinking agents. Polyurethane-urea elastomers are widely used in various molded article manufacturing industries, and are produced from organic polyisocyanates and compounds having active hydrogen atoms that can react with the isocyanate groups. . Compounds having active hydrogen atoms are organic compounds having a molecular weight of 400 to about 12,000, typically polyols of the polyether or polyester polyol type. There are many types of polyurethane, but to distinguish between these polyurethanes, it is often necessary to distinguish between, for example, cast elastomers, which are produced by the casting method, and cast elastomers, which are produced by a technique called reaction injection molding. They are classified by manufacturing method, such as RIM elastomers. Furthermore, foamed elastomers are classified based on their properties, both rigidity and flexibility. Reaction injection molding (RIM) is used today to manufacture molded parts,
Particularly widely used in the automobile industry, molded parts that can be manufactured using this method include, for example, automobile grilles, bumpers, headlights and taillight supports, and typically weigh between 3 and 10 kg. There are large molded products that can weigh up to 100 yen or more. In reaction injection molding, highly reactive raw materials are mechanically mixed by high-speed collision of multiple streams, and the resulting mixture is transferred into a mold within an extremely short time using high-speed and high-pressure supply means and equipment. It consists of ejecting. In this molding, large quantities of liquid, highly reactive raw material are introduced into a mold within a very short time and then hardened. The time is usually about 1 to 5 minutes. Reaction injection molding (RIM) methods are described in the following patents: U.S. Pat. No. 4,218,543 discloses the use of crosslinkers or chain extenders to impart rigidity to the resulting urethane system.
Methylene diphenyl isocyanate-polyol system using aromatic diamine as extender)
Discloses the RIM method. In the preferred embodiment shown in this patent, diethyltoluenediamine, in which the ethyl group is located ortho to each amino group, is used as the chain extender. As disclosed in this patent, toluenediamine and many other aromatic diamines are either too reactive or have too slow cure times for practical RIM processes. U.S. Patent No. 4,374,210
In contrast to the one-shot process shown in US Pat. No. 4,218,543, a special RIM process using prepolymers of reactive isocyanate materials is disclosed.
Many polyisocyanate-prepolymers are
It can be used in the RIM method, however,
All are 4, as isocyanate.
The basic type is 4'-methylenebis(phenyl isocyanate). Aromatic diamines having an alkyl group as a substituent ortho to each amino group are used as chain extenders. An example of an aromatic diamine preferred for this method is diethyltoluenediamine. U.S. Pat. No. 4,048,105 describes the preparation of polyurethane-urea elastomers from aromatic diisocyanates, polyols, and aromatic diamine chain extenders. This elastomer is made by reacting a prepolymer of aromatic diisocyanate and alkanediol with a blend of polyols containing long chain polyols. US Pat. No. 4,440,952 discloses the use of a monoisopropyl derivative of toluenediamine in which the isopropyl group is ortho to the amino group as a chain extender for polyurethane-urea systems. U.S. Pat. No. 4,487,908 discloses the production of reaction injection molded urethane elastomers from organic polyisocyanates, polyols, and aromatic diamine chain extenders. In this case, alkenylsuccinic anhydride is used to increase the green strength of the polymer.
It is said to be preferable as a kind of additive for improving the strength. There are also a number of patents disclosing the use of various aromatic diamines in the production of polyurethane elastomers and foams, including the following: US Pat. No. 3,752,790 discloses chlorinated toluenediamine as an aromatic diamine for crosslinked urethane systems. The electronegative nature of the chlorine atom reduces the activity of the aromatic ring, resulting in a retardation of the reaction rate. Chlortoluenediamine derivatives are preferred for large scale production requiring formulations with a long "pot life". US Pat. No. 4,365,051 discloses various aromatic amine esters and nitriles as urethane crosslinking agents. For example, various alkyl diamino t-butyl benzoates or diamino t-alkyl benzonitriles.
The aforementioned U.S. Pat. No. 4,218,543 and U.S. Pat.
In contrast to the 4374210 specifications, the nitrile and benzoate groups are in the meta position of the amino group and not in the ortho position. Nitrile and ester groups reduce the activity of the aromatic rings and extend the pot life of the formulation. US Pat. No. 3,428,610 discloses the preparation of crosslinked polyurethanes using alkylated toluenediamines in which the alkyl group is attached in the ortho position to the amino group. This patent suggests a number of organic polyisocyanates and polyols as suitable for crosslinking with alkyl aromatic toluenediamine chain extenders. U.S. Patent No. 3,846,351 describes polyurethane
The use of sec-aromatic alkyldiamines as chain extenders and blowing catalysts for compositions for producing urea elastomers is disclosed. N,N'-di-sec-butyl-p-phenyl diamine is an example of an amine with chain extension and catalytic activity. EP 0 069 286 discloses cellular polyurethanes containing alkyl-substituted phenyl diamines as chain extenders. All the diamines shown here have an alkyl substituent in the respective position ortho to the amino group. U.S. Patent No. 3,280,879 describes polyurethane
The use of N-mono-alkyl-aromatic diamines as chain extenders in urea elastomers is disclosed. Additionally, although U.S. Pat. No. 4,482,690 does not correspond to prior art to the present application, it is possible to prepare polyurethane-urea elastomers using t-butylbenzenediamine as a chain extender for polyurethane-urea formulations. discloses a method to do so. T-butylbenzenamino has been shown to be a chain extender diamine that gives a longer "pot life" to the urethane formulation and provides excellent tensile montage to the resulting urethane-urea polymer. The present invention uses an organic polyisocyanate of about 400 to
A process for producing polyurethane-urea elastomers by reacting an organic compound having a molecular weight of 12,000 and having at least two active hydrogen atoms determined by the Tserevitinov method with an aromatic diamine as a chain extender. It is about improvement.
The improvement is that the third
The aim is to use mono-t-alkyltoluene diamines in which the alkyl group is ortho to the amino group. Mono-t-butyl-toluene diamine is preferred as an example of a substituted diamine. Many advantages are obtained when using mono-t-alkyltoluene diamines as the aromatic chain extender or diamine chain extender component in the preparation of polyurethane-urea elastomers. Their advantages include extended pot life of polyurethane-urea elastomer molding compositions compared to both unsubstituted aromatic diamines and mono- and dialkyl-substituted toluene diamines; reduced heat sag; Polyurethane-urea elastomers are produced with good physical properties, including; ease of handling and processing as aromatic diamine chain extenders that do not exhibit mutagenic activity in the Ames test can be used; The above problems are alleviated; the process versatility in producing castable elastomers from toluene diisocyanate systems; the flexibility and variability of the molding process using reaction injection molding (RIM) technology; and the ability to use high levels of chain extender in the polyol to obtain an elastomer with reduced thermal sag without skin core delamination. Figures 1-2 show rheology test data for aromatic diamines shown as a function of time. Figures 3 and 4 show the bending modulus and thermal instability as a function of chain extender concentration in the polyol. In a general embodiment of the present invention, (a) an organic polyisocyanate is combined with (b) a compound having an active hydrogen atom as determined by the Tzelevitinoff method, and (c) an aromatic amine chain extender. A polyurethane-urea elastomer is produced by the reaction. Tselevitinoff's method is one of the methods for quantifying active hydrogen atoms in compounds, in which a solution of methylmagnesium iodide is added to a solution of the compound,
This method collects the generated methane, measures its volume, and then calculates the number of active hydrogen atoms in the compound. The polyisocyanate reaction component (a) used as the raw material compound for the urethane-urea elastomer is aliphatic, cycloaliphatic, araliphatic, aromatic, and heterocyclic isocyanates commonly used in the polyurethane-urea elastomer manufacturing industry. Any of these may be used. As a general rule, it is particularly preferred to use aromatic polyisocyanates with the chain extender systems described herein. These polyisocyanates include toluene, 2,4-
and 2,6-diisocyanate. Others include phenyl diisocyanate, polyphenyl-polymethylene polyisocyanate, 4,4'-
Methylene bis(phenyl isocyanate), naphthalene-1,5-diisocyanate, cyclohexenyl-1,4-diisocyanate, dicyclohexylmethane-4,4-diisocyanate, bis(3-methyl-3-isocyanate phenyl)methane, dianisidine diisocyanate ,and so on. Among these, 4,4'-methylenebis(phenyl isocyanate) (MDI) is preferred. It has excellent RIM method characteristics,
This reduces the risks associated with handling the formulation. Reactant component (b) used in the preparation of polyurethane-urea elastomers is a compound having at least two active hydrogen atoms, as determined by the Zelevitinoff method. Typically polyols such as polyethers, terminal amine polyols, and polyester polyols. The molecular weight of these polyol compounds ranges from about 400 to 12,000, preferably from 1,000 to about 6,000. Examples of polyols suitable for the production of polyurethane elastomers include polyether polyols such as poly(propylene glycol), poly(ethylene glycol), poly(tetramethylene glycol);
There are polyester polyols produced by the reaction of polycarboxylic acids with various polyols.
Polyester polyol systems are well known and include, for example, polycarboxylic acids such as succinic acid, adipic acid, phthalic acid, isophthalic acid,
Some are derived from polyols such as glycerol, ethylene glycol, propylene glycol, 1,4-butanediol, trimethylolpropane, and pentaerythritol. Also,
Polyether polyols can also be reacted with polycarboxylic acids to form polyester polyols. The aromatic amine chain extender in an embodiment of the invention is a mono-t-alkyltoluenediamine in which the tertiary alkyl group is ortho to the amino group. Substituted derivatives of this can also be used. This aromatic amine is used as a chain extender in polyurethaneurea elastomers or as a component of a chain extender that provides urea groups in the elastomer. The few chain extension groups form "hard" portions in the elastomer, improving the structural stability and tensile modulus of the resulting polyurethane-urea elastomer. In order to realize the object of the invention, in the formulation,
At least 50 equivalent %, preferably 100 equivalent % of the chain extender is mono-t-butyltoluenediamine. In many cases, up to 50 equivalent percent of the chain extender system consists of other aromatic diamines. The type and proportion of chain extenders to be used are selected based on desired characteristics such as fast or slow reaction rate. Short or long chain polyols can also be used with mono-t-alkyltoluenediamines to form a mixture of chain extenders. Such polyols include ethylene glycol, propylene glycol, butanediol, glycerol and other conventional ones. Although long chain polyols are generally not preferred as components of chain extenders, they can be used in prepolymer formulations. Typically, if a polyol is used as a component of the chain extender system, at least 25%, and preferably at least 75%, of the free NCO equivalents will be donated by the t-alkyltoluenediamine. If the “one shot” method is used, this release
The NCO content is based on the NCO available after the reaction of the aromatic diisocyanate with the organic compound containing active hydrogen atoms is completed. Examples of the mono-t-alkyltoluenediamine compound used in the method of the present invention include compounds represented by the following formula. [Formula] [Formula] [Formula] In the formula, R ₁ , R ₂ and R ₃ are C ₁ to _{C 3} alkyl groups, or R ₂ and R ₃ together are C ₅ to _{C 6}
Forms a member ring. An important difference between the compositions disclosed by the present invention and those of the prior art is that the compositions of the present invention:
It has only one monoalkyl group, this monoalkyl group is ortho to one amino group, and this alkyl group is a tertiary-alkyl group. As mentioned above, the aromatic diamines include derivatives of 2,4-, 2,6-, 2,3- and 3,4-diaminotoluene.
The methyl group is in position 1 in this case. The toluenediamine compounds of the present invention are synthesized by alkylation of aromatic toluenediamine, in contrast to the alkylation of aromatic hydrocarbons and subsequent amination via a nitration reaction. This is because, in order for the alkyl group in the aromatic composition to be in the ortho position with respect to the amino group, an alkylation reaction can be performed on the aromatic amine. If alkylation is carried out first,
That is, unlike aromatic amines, when an aromatic hydrocarbon or a dinitroaromatic hydrocarbon is subjected to an alkylation reaction, the alkyl group moves to the para position relative to the methyl group. Substituted toluenediamines with available positions ortho to the amino group can be alkylated. of the isocyanate
Substituents inert to the NCO content are unsubstituted t
- It is also possible to change to an aromatic diamine which is more reactive than the alkyltoluene diamine. Such substituents include halogen atoms such as chlorine atoms,
There are ester groups, etc. However, preferred are those having no substituents. In the production of alkylated aromatic diamines, many techniques use homogeneous catalyst systems;
It is not particularly suitable for the production of 2,4-diamine or 1-methyl-3-t-butyl-phenylene-2,6-diamine compositions. Many homogeneous catalyst systems do not have sufficient activity to introduce tertiary butyl groups into aromatic rings. For information on the use of homogeneous catalyst systems, see "J.Org.Chem."
22, 693 (1957). In contrast to previous prior art, t-butyltoluenediamine is capable of producing _C4 - _C10 olefins such as isobutylene, isoamylene, 1-methylcyclopentene, 1-methylcyclohexene, 2-methyl-2-butene in liquid phase or It is produced by reaction with toluenediamine in the gas phase in the presence of an acidic catalyst at temperatures of about 100-250°C. The effective pressure (gauge pressure) for the reaction is approximately 1.06 to 1.41Kg/cm ²
(about 15-2000 psig) preferably about 7-70 Kg/cm ²
(100-1000 psig). Reaction time is usually 2~
48 hours. The reaction molar ratio between olefin such as isobutylene and toluene diamine is approximately 1 to 10:1.
It is. A nitrogen or other inert gas purge is usually used to remove traces of oxygen or moisture from the reactor that would interfere with the reaction. The reaction products are immediately recovered by known techniques. First, the catalyst is removed and then the product is separated, if necessary, by distillation. Acidic catalysts suitable for the practice of this invention are those in the solid phase, including silica-alumina, montmorillonite, diatomaceous earth, kaolin, and natural or synthetic zeolites. Of these catalytic materials, silica-alumina and zeolite are preferred. Particularly suitable are hydrogen and rare earth exchanged mordenite or Y-type zeolite. Montmorillonite and silica-alumina make it possible to produce substantial amounts of di-t-butyltoluenediamine from the 2,6-toluenediamine isomer, and this product, if not separated, will reduce the reactivity of the mixture. It can be changed. The H-Y type zeolite acts particularly selectively on the mono-t-butyltoluenediamine product. The alkylated amines may themselves be blends, e.g., mixtures of 2,4- and 2,6-isomers, or other e.g. 2,3-, 3,
The 4- and 2,5-toluenediamine derivatives may be used in combination with other aromatic diamines and alkylated diamines. The 2,4-isomer is approximately
A mixture of t-butyl-2,4- and 2,6-diaminetoluene isomers consisting of a weight ratio of 65 to 80% and 20 to 35% of the 2,6-isomer is effective. One of the reasons for this is that the commercially available raw material toluenediamine is usually about 80% 2,4-isomer and 20% 2,4-isomer.
6-isomer in trace amounts, e.g. 2-5% of the 2,3-
and 3,4-t-alkyl derivatives. The second reason is
A mixture of 65-80% by weight of 5-t-butyl-2,4-diaminotoluene isomer and 20-35% by weight of 3-t-butyl-2,6-toluenediamine isomer is a 2,4-isomer. Small amounts of the 2,6-isomer are sufficient to extend the reaction time required for larger, more complex, and more precise molding than when using the 2,6-isomer alone or when using diethyltoluenediamine. This is because it is advantageous for reaction injection molding (RIM). Additionally, this 80/20 mixture is a supercooled liquid (mp. 38°C) that can provide great flexibility in handling the urethane formulation. As can be seen from the attached drawings, 3-t-butyl-
The 2,6-diaminotoluene isomer and 5-t-butyl-3,4-diaminotoluene are less active in urethane systems than the 5-t-butyl-2,4-diaminotoluene isomer. If 5-tert-butyl-2,4-diaminotoluene cannot be used because of its reactivity, the former isomer is often
Each can be used to manufacture RIM molded products. The general method of elastomer production is typically 5
It consists of preparing a prepolymer containing ~25% by weight of free isocyanate and then reacting this prepolymer with a stoichiometric amount of an aromatic amine chain extender. In this process, the free isocyanate content of the prepolymer within this range varies depending on the type of molding process performed. Higher levels of free isocyanate, for example 15-23% by weight, are acceptable in the production of small rigid molded articles. For the production of large, flexible products, lower isocyanate contents, for example from 5 to 15% by weight, are required. As shown in the aforementioned U.S. Pat. No. 4,374,210, the prepolymer route has the advantage for the molding process that the amounts of reactants fed to the molding machine are substantially equal. ing. Another process used to produce urethane-urea elastomers is the so-called "one shot process." In this type of manufacturing, all the reactants are blended in a nozzle and immediately injected into a mold. This technique is described in the aforementioned U.S. Patent No. 4,218,543.
It is also disclosed in the issue. The use of catalysts is usually essential to the production of polyurethane-urea elastomers. This is because, in the absence of a catalyst, rapid curing molding within industrial molding time ranges and the desired mechanical properties required for polyurethane-urea elastomers are not achieved. Catalytic systems suitable for catalyzing isocyanate hydroxy reactions are known in the art, and generally include organometallic compounds such as organotin compounds. Examples are tin() salts of carboxylic acids such as Sn()octoate and Sn()laurate. Dialkyltin salts of carboxylic acids, such as dibutyl Sn dilaurate, dioctyl Sn diacetate, and dibutyl Sn maleate, are also used. Other catalyst components include tertiary amines such as toluenediamine, triethylamine, N-methyl-N'-(dimethylaminoethyl)piperazine and N-ethylmorpholine. Tertiary amines also include triethanolamine, triisopropanolamine, N-methyl-diethanolamine and similar compounds thereof. Catalysts are generally used in amounts ranging from 0.01 to 10% by weight, preferably from 0.05 to about 1% by weight, based on the polyol used in the reaction system. For the production of polyurethane-urea elastomer,
A foaming agent may be used for the purpose of forming bubbles inside the molded product. The blowing agents commonly used are water or volatile organic systems, including acetone, methanol, chloroform,
Included are halogen-substituted alkanes such as monofluorotrichloromethane and chlorodifluoromethane, and ethers such as diethyl ether. Additionally, various surface-active additives, foam stabilizers, and foam control agents can be used in the production of elastomers. An alkali metal or ammonium salt of sulfonic acid, such as dodecylbenzenesulfonic acid, is an example of a surface-active additive. Water-soluble polyether siloxanes are commonly used as foam stabilizers and fatty alcohol paraffin or dimethylpolysiloxanes as foam control agents. A mold release agent is used to facilitate recovery of the cured polyurethane-urea elastomer from the mold. Conventional mold release agents can also be used. The following examples illustrate embodiments of the present invention for the synthesis of alkylated aromatic diamines and polyurethanes.
The use of these alkylated diamines in the production of urea elastomer systems is shown. Example 1 Synthesis of 3-t-butyl-2,6-toluenediamine This synthesis of ortho-t-butyltoluenediamine (hereinafter referred to as t-butyl TDA) was carried out in approximately 1 gallon equipped with a mechanical stirrer. The reaction was carried out using a pressurized stainless steel reactor. The reactor was charged with 150 g of a powdered commercially available silica-alumina catalyst containing 13% alumina and 1500 g.
(12.24 mol) of 2,6-toluenediamine was charged. The autoclave was sealed and purged with nitrogen. After that, the pressure is approximately 1.13Kg/cm ² (16psig)
And so. The contents of the reactor are stirred at a constant rate.
Heated to 200°C. Next, 870 g (15.5 mol) of isobutylene was fed into the reactor over 30 minutes.
added. Initial reaction pressure is approximately 68.19Kg/cm ²
(970 psig). The reaction mixture was kept at a temperature of 200° C. for about 45 hours with constant stirring. After 45 hours, the contents of the reactor were cooled to approximately 150°C and
Stirring was stopped. The reactor was opened and the contents were collected. The catalyst was recovered from the reaction mixture by filtration. The reaction product was analyzed by gas chromatography, and the following analytical results were obtained. Table: Both mono and di-t-butyltoluenediamine products were produced. The product was separated by distillation to obtain the 3-tert-butyl-2,6-toluenediamine isomer as the chain extender. Example 2 Synthesis of 5-t-butyl-2,4-toluenediamine A 300 c.c. Hestalloy C pressure reactor equipped with a mechanical stirrer was used for the production of t-butyltoluenediamine. Approximately 100 g (0.819 mol) of 2,4-toluenediamine is charged to the reactor, and 5 g of 36% aqueous hydrochloric acid are added at the same time. The reactor was sealed and purged with nitrogen gas. Approximately 2.32 Kg/cm ² (33 psig).
The contents of the reactor are then continuously stirred
Heated to 180°C. Isobutylene was fed into the reactor and 53.4 g (0.96 mole) was added over 15 minutes. During the course of this isobutylene addition, the pressure within the reactor increased to approximately 53.85 Kg/cm ² (766 psig). The reaction mixture was then heated to 180°C with constant stirring.
It was kept for 24 hours. Then increase the pressure to approximately 36.8Kg/cm ²
(524 psig). The contents were cooled to 160°C and stirring was stopped. The reaction vessel was opened and the reaction products were analyzed. Its composition is as follows. Table: 5-tert-butyl-2,4-toluenediamine isomer was recovered by distillation. Example 3 Synthesis of 3-t-butyl-2,6-toluenediamine 15.0 g of powdered H-Y type zeolite catalyst,
140.0 g (1.15 moles) of 2,6-toluenediamine was added to a 1000 c.c. Hastalloy pressure reactor (similar to Example 2) with a mechanical stirrer.
It was loaded into The reactor was sealed and purged with nitrogen gas to a pressure of about ²⁰⁰ psig at room temperature. The contents were heated to 180°C with stirring. Isobutylene (267 g, 4.76 mol) was added to the reaction mixture over 20 minutes. The initial reaction pressure was approximately 77.33 Kg/cm ² (1100 psig). This resulted in an isobutylene:toluene molar ratio of 41:1. Add the reaction mixture under constant stirring.
It was kept at 180℃ for 30 hours. The reaction products were separated by the procedure of Example 2. The product had the following composition: [Table] The results in terms of conversion and selectivity to the mono-t-butyl-toluene diamine isomer were better than those obtained with the conversion of the 2,6-diaminotoluene isomer in Example 1. . The 3-t-butyl-2,6-toluenediamine product was recovered by distillation. 80/20 of 2,4- and 2,6-tBTDA isomers
A mixture can be made by substituting an 80/20 mixture for the 2,6-tBTDA isomer in this example. Example 4 A series of polyurethane preparations using various chain extenders.
A urea elastomer was produced. To determine the reactive activity of chain extenders in correlated standard urethane formulations, pot life was evaluated by a pot life test. Polyurethane-urea elastomer is a 2,4-
The NCO content of poly(1,4-oxytetramethylene) glycol end-capped with toluene diisocyanate is approximately 5 to 5.
A prepolymer at 7% was prepared by reacting with the chain extender aromatic diamine and diol to be tested. The standard stoichiometric equivalence ratio of isocyanate: diamine chain extender: diol is 2:1:1. In actual production, the prepolymer is manufactured by DuPont (EIduPont de
Poly(ε-caprolactone) diol is commercially available under the trade name ADIPRENE L-167 from Interox Chemicals Co., Ltd.
Limited)'s CAPA 200 is available as a commercially available product. The test system for measuring pot life is 7g.
A constant temperature (50
It consists of a heated test chamber in a temperature range (°C) and is equipped with a vertically penetrating piston. This piston moves up and down inside the test sample over time. (Temperature increases due to exothermic reactions are discounted.) The force required to move the piston inside the polymer sample is measured in arbitrary units. Display the interconnectedness of this force as a function of time.
This force-pot life interaction for urethane during curing is then related to the force-viscosity interaction for urethane-urea production. [Table] Min

Table 1 provides numerical values of the experimental model coefficients, expressed as the 10 logarithm of viscosity, as a polynomial function of the three-element force of time for several chain extenders. The coefficient is given as: log (viscosity) = I + A (time) + B (time) ² + C (time)
³ The first force (A) coefficient is a "quasi" reaction rate constant that estimates the initial reactivity. A smaller value for the "quasi" rate constant (A) indicates a longer and more desirable pot life. The value of T-5000 is the time at which the reaction product has a relative viscosity of 5000 units. Although this value is arbitrary, it is suitable for use in determining the performance of test materials in RIM or cast elastomer processes. For relatively small and simple molded products, the J-5000 can be used in about 2.5 minutes, but for large or complex molded products, it can take up to 5 minutes.
More T-5000 time may be required, such as more than 10 minutes. Figures 1 and 2 show the results obtained for the test substances. These figures illustrate the use of another type of aromatic diamine chain extender, tBTDA.
5-t-butyl-2,4-diaminotoluene (5tB24TDA) and 3-t-toluene diamine product compared to an 80/20 mixture of
The relative potency of the butyl-2,6-diaminotoluene isomer (3tB26TDA) is shown. As Figure 1 shows, 3tB26TDA (curve 4) is
Diethyltoluenediamine (DETDA), which shows an almost linear increase in strength and is the reference material of the prior art.
Rather, the reaction has been slow in practice.
The 80/20 mixture (curve 2) also reaches the liquid state later than DETDA (curve 1). On the other hand, G-t
The -2,6-isomer reacts much faster than the mono-t-isomer (T-5000 in Figure 1 is replaced by T-5000 in Figure 2).
–5000). mono-t-butyl-2,
4-diamino-meta-xylene isomer is 80/20
It reacts much faster than the mixture or the 2,6-isomer itself. In summary, Figures 1 and 2 illustrate the balance between steric delay reactions and electron donating effects. If the 2,6-TDA isomer is alkylated with isobutylene in two ortho positions instead of one, the reactivity in the production of polyurethane/urea is increased rather than reduced. For example, T
-5000 is from 17.8 minutes of mono-substituted 2,6-TDA.
decreases to 11.3 min for the disubstituted compound. Steric hindrance blocking around less reactive amino groups is
The same is true in each case ( _-NH2 group is surrounded by _-CH3 groups and the nearest -C( _CH3 ) ₃ groups). however,
In the case of 35DtB26TDA, the second −C(CH ₃ ) ₃
The alkyl group provides extra electron donation that promotes the reaction. This means that 5-t-
Butyl-2,4-benzenediamine (T-5000=
10.7 min) versus 5-t-butyl-2,4-diamino-
It can also be seen for meta-xylene (T-5000 = 2.6 minutes). In the case of meta-xylene derivatives, the steric blocking effect of one t-butyl group is counteracted by the activating effect of amine reactivity upon addition of two methyl groups to the aromatic ring. That's what happens. If the t-butyl group is not in the ortho position of the reactive amine substituent, there is only an activating effect due to the alkyl substituent. This means that 4-t-butyl-2,6-toluenediamine produced by nitration/reduction of para-t-butyltoluene reacts very quickly, and T-5000 is
This is proven by the fact that it is only 0.5 minutes and A (time) is 3.87. Example 5 Physical testing was performed on a series of polyurethane-urea cast elastomer samples using a handmix technique. More specifically, a prepolymer capped with a conventional isocyanate (Adiprene L-
167] was degassed at a temperature of 90 to 100°C and a pressure of 5 to 14 mmHg. The bubbling process was stopped and the sample was used immediately. A preselected amount of isocyanate prepolymer was then mixed with the chain extender at 75° C. and under atmospheric pressure. As the chain extender used, T-5000 shown in Example 4 was used for 10 minutes or more. After mixing the chain extender with the prepolymer, the resulting mixture was poured into an aluminum mold and cured by applying pressure to about 175.75 Kg/cm ² (2500 psig) with a hydraulic press at a temperature of 100°C. After 2 hours, the samples were removed from the mold and cured in an air oven for 22 hours at 100°C.
Post-curing was carried out at room temperature of 25-30°C for 7 days. Prior to testing, the sample was heated to a temperature of 23 ± 2°C and a relative temperature of 50 ±
It was left under the conditions of 5 for 24 hours. Table 2 shows the tensile modulus, tensile strength at break,
Physical property test results are shown for elongation at break, tear resistance and durometer hardness, measured according to ASTM methods. To explain in more detail, the tensile strength at a given elongation and failure is determined by ASTM
Tear resistance is ASTM D per D 1708
624 (Die C), and the durometer hardness is
Measured according to ASTM D 2240. EXAMPLE 6 Physical testing was performed on a series of polyurethane-urea elastomer samples using reaction injection molding (RIM) techniques. For this purpose, the diethyltoluenediamine isomer (2,4-
and 80/20 mixture of 2,4- and 2,6-isomers), the usual chain extenders for RIM production.
Each was compared with an 80/20 mixture of 6-mono-t-butyl-toluenediamine isomers. In addition, a specific t-butyltoluenediamine isomer was evaluated for DETDA. The method of urethane synthesis was the same, and direct comparisons were made with different polyols and isocyanates. More specifically, reaction injection molded (RIM) elastomers are manufactured by the SA8-20 experimental machine (LIM Kunststoff Technology) suitable for binary mixture processes.
Technologie GmbH, Kittsee, Austria). This experimental machine uses two 10-30 c.c. metering pumps for component "A" (methylene diphenyl diisocyanate, MDI) and component "B" (polyol + chain extender + catalyst). . This pump is simultaneously driven by a chain gear driven according to the mixture by a variable speed (50-250 rpm) motor. Components A and B are each directed to the mixing chamber by controlled compressed air operated valves. Continuously by frequency converter
A high speed rotor that can be adjusted to 10,000-18,000 rpm mixes these components. After mixing,
The pump block and mixing head are automatically advanced to stationary form by means of compressed air. Although the flow temperature can be controlled, it was set to 50°C. The mold is self-temperatured throughout the injection molding operation, even before it is placed on the jig through which the mixing head is guided. These molds are made of 100 x 26 x 27 x 4 cm aluminum.
The cavities were 200 x 2 mm and 200 x 200 x 3 mm. Prior to the injection operation, the mold was treated with a release agent. In some cases, an isocyanate index of 1.05 was attempted for all elastomers, and a mechanical check was performed for unmixed components A and B through the sampling port. In other cases, an isocyanate index of 0.94 was sought to determine the effect of isocyanate on the physical performance of urethane/urea elastomers. After the injection was completed, while the mold was being lowered and opened, the mixing rotor was cleaned with dioctyl phthalate and purged with nitrogen in preparation for the next injection shot. The molded product is heated at 60℃ for 12 hours as shown in the table.
After curing for 1 hour at 23 ± 2 °C or 1 h at 125 °C to remove the mold release agent, 2 mm thick specimens were prepared at a temperature of 23 ± 2 °C, 50 ± 5 °C for curing, tensile, and tear tests.
% relative humidity. The physical properties are
Measured according to ASTM method. Among these are hardness (ASTM D 2240) and tensile (ASTM D 1708) (measurements are the average of five determinations), tear resistance (ASTM D 624, die
C) (average of three determinations). Additionally, yield tensile is reported for crosslinked RIM elastomers based on the shape characteristics of Instron stress-strain curves. Also, bending modulus and maximum stress (ASTM D 1708) (five 2.54×
Measured on each of the 7.62cm (1″ x 3″) pieces) and sag, 100mm using 3mm thick moldings
Thermal stability values (ASTM D 3769) measured for 4 inch overhang specimens are also shown in the table. Tables 3, 4, and 5 below are the results of these tests. [TABLE] [TABLE] [TABLE] [TABLE] [TABLE] All test specimens were prepared using Updillon diisocyanate and Dow polyol. The catalyst was Dabco's 33-LV toluethylenediamine in propylene glycol and M
&T T-12 dibutyl dilaurate, each used at 0.05% by weight of the polyol. The temperature of the component stream is 50℃ for each purpose, the mold temperature is 70℃, and the demolding time is 2-3
The post-curing was carried out at 125° C. for 1 hour. Tensile and tear data are for 2mm thickness, 200
The bending modulus and sag are from a 3 mm thick, 200 mm x 200 mm molded product. Thermal stability was measured on 3 mm thick specimens with a 10.2 cm (4'') overhang. The mold release agent was Chemtrend 136.
DETDA was diethyltoluenediamine, commercially available from Ethyl Corp. t
-BTDA is t-butyltoluenediamine. The equivalent weight of each is 89.1 g. The subscript /L is tBTDA produced in the laboratory.
, /P indicates a pilot plant material similar to that used in liquid injection molding machines.
Only tBTDA acts as a chain extender in polyols above 30 pph. At this level,
The DETDA specimen has reached skin-core delamination. From Table 3, it appears that the physical properties of equivalent amounts of DETDA and tBTDA are similar, but they are strikingly different for the four polyols tested.
tBTDA's RIM elastomer exhibits superior extensibility (less stress at the same strain) and greater maximum elongation. However, it has slightly lower thermal stability. The contribution to physical properties based on each t-butylated toluenediamine isomer is shown in Table 4. The 0.95 and 1.05 data shown for isocyanate confirm that slightly more isocyanate is advantageous over slightly less. Of the two isomers of tBTDA, 3-t-butyl-2,6-toluenediamine acts to increase thermal instability, and the tensile strength and maximum % elongation are also reduced. This may be due to the fact that 3tB26TDA has poor symmetry between the two isomers. In Table 4, the data for 4tBTDA is shown at a level of chain extender of 22 pph (parts by weight chain extender/100 parts by weight polyol) in the polyol.
It is compared with. This tBTDA isomer exhibits a slightly larger bending modulus and also DETDA
For sag (Sag) 0.46cm (0.18 inch)
0.84cm (0.33 inch) and 0.51cm (0.20 inch)
Slightly less thermal stability as indicated by sag. At 30 pph relative to polyol, DETDA is difficult to mold and pre-gelation occurs, with test moldings approaching skin-core delamination. At this level of chain extender, the bending modulus is
The reduction in thermal sag is also much greater for the tBTDA isomer than for DETDA, which is 0.15 cm (0.06 inch) for a 10.2 cm (4″) overhang specimen.
and an excellent 0.10 cm (0.04 inch). At a level of 35 pph of chain extender,
Manufacturing with DETDA is not possible and the bending modulus of tBTDA is dependent on the NCO index.
72,000 to 82,000, and the thermal sag is very small, down to 0.02 for an NCO index of 1.05. Similarly low thermal sag values and high flexural modulus values are also achieved with amine-terminated polyol-MDI prepolymer systems.
The 50% slower reactivity of tBTDA relative to DETDA allows for slower processing of comparable strength components or comparable reaction rate systems for higher strength component formulations. be.

[Brief explanation of drawings]

Figures 1 and 2 show rheometer data for polyurethanes using various aromatic amine chain extenders, and Figures 3 and 4 show the tBTDA of the present invention as a chain extender. and polyurethane using DETDA as a control.
This shows the bending modulus and thermal instability of urea elastomer.

Claims (1)

[Scope of Claims] 1. A method for producing a polyurethane-urea elastomer, comprising (a) an organic polyisocyanate, (b) at least two polyisocyanates having a molecular weight of 400 to 12,000 and determined by the Tselevitinov method. When reacting with an organic compound containing an active hydrogen atom and (c) an aromatic diamine chain extender and curing the resulting reaction product, at least a portion of the aromatic diamine used as the chain extender is a tertiary diamine. _The following formula in _{which the} alkyl group is ortho to the _amino group: A method for producing a polyurethane-urea elastomer, characterized in that the polyurethane-urea elastomer is a mono-tertiary-alkyltoluenediamine represented by ( ₂ and _R3 taken together to form a _C5-6 membered ring). 2. At least 50 equivalent % of the total amount of aromatic diamine chain extender used in the reaction with free isocyanate.
The method according to claim 1, wherein is a tertiary-alkyltoluenediamine. 3. Reacting an isocyanate with said organic compound to form a prepolymer having a free isocyanate content of 5 to 25% by weight, and then treating this prepolymer with said aromatic diamine chain extender consisting of a mono-tertiary-alkyltoluenediamine. The method according to claim 2, wherein a polyurethane-urea elastomer is produced by reaction. 4 Mono-tertiary-alkyltoluenediamine is 2,
4. The method according to claim 3, wherein 6-diamino-3-tert-butyltoluene is used. 5 Mono-tertiary-alkyltoluenediamine is 2,
4. The method according to claim 3, wherein 4-diamino-5-tert-butyltoluene is used. 6 Claim 4 in which the isocyanate is 4,4'-methylenebis(phenyl isocyanate)
The method described in section. 7. Claim 5 in which the isocyanate is 4,4'-methylenebis(phenyl isocyanate)
The method described in section. 8 Mono-tert-butyltoluenediamine is 65-80
wt% 2,4-diamino-5-tert-butyltoluene and 20-35 wt% 2,6-diamino-3-
The method according to claim 3, which is a mixture containing tert-butyltoluene.