WO1996017880A1

WO1996017880A1 - Novel polyurethane toughener, thermosetting resin compositions and adhesives

Info

Publication number: WO1996017880A1
Application number: PCT/US1995/015825
Authority: WO
Inventors: Clarence Lynn Mahoney; David Scott Le Grand
Original assignee: The Dexter Corporation
Priority date: 1994-12-06
Filing date: 1995-12-06
Publication date: 1996-06-13

Abstract

A linear polyurethane polymer containing phenolic hydroxyl functionality for reaction with a thermosetting resins comprising a linear polyurethane of recurring units containing linear ester or ether moieties or a combination of ester and ether moieties which are interbonded through urethane groups and uriedo bonded phenolic hydroxyl-containing terminal groups. The linear polyurethane polymer has formula (I) wherein a and b are each 1, 2 or 3, n is at least 1, each X is a divalent organic radical containing at least two carbon atoms in which the N are bonded to different carbon atoms of X, R is an aliphatic polyester or polyalkylene oxide wherein the aliphatic polyester is a polyester of an alkylene diol and an aliphatic carboxylic acid, or a polycaprolactone polyol, and the alkylene group of the polyalkylene oxide contains on average greater than three carbon atoms and not greater than five carbon atoms, and R° is an organic aromatic containing group in which the OH and N bonded to the R° group are bonded directly to different carbon atoms and the OH is bonded directly to an aromatic containing carbon atom. Adhesives, adhesive films, and thermosetting compositions are described.

Description

Novel Polyurethane Toughener , Thermosetting Resin Compositions And Adhesives

Brief Description Of The Invention

A polymer suitable for use as a toughener for composite and adhesive formulations having the formula :

wherein a and b are each 1, 2 or 3, n is at least 1, X is a divalent organic radical containing at least two carbon atoms in which the N are bonded to different carbon atoms of X, R is an aliphatic polyester or polyalkylene oxide wherein

• the aliphatic polyester is a polyester of an alkylene diol and an aliphatic carboxylic acid, or a polycaprolactone polyol, and

• the alkylene group of the polyalkylene oxide contains on

average greater than three carbon atoms and not greater than five carbon atoms, and

R° is an organic aromatic containing group in which the OH and N bonded to the R° group is bonded directly to different aromatic carbon atoms. A thermosetting resin composition containing the polymer of formula (I) and a cured resin composition containing the polymer of formula (I) .

Synergistic combinations of the polymer of formula (I) and other toughener polymers are useful in improving the

toughening properties of thermosetting resin formulations for making composites and adhesives. Background Of The Invention

Thermosetting polymers have many useful properties for structural applications as adhesives, composite matrices, etc. They have high modulus and strength, low creep and good performance over broad temperature ranges. However, they are often relatively brittle materials and can fail where crack initiation and stress concentration can occur. A major advancement in improved properties and suitability over broader application areas has come about through generation of toughness through incorporation of various rubbery materials which form discrete particle second phases. Through proper selection of both continuous matrix and second phase

materials, a great increase in toughness or insensitivity to stress concentrations can be attained without major impairment of other desirable performance properties. Epoxide resins systems have shown the most useful benefit from incorporation of toughening materials but phenolics, polyimides, polyesters and many thermoplastics also show improved properties.

Materials used to toughen such thermoset and thermoplastic materials include reactive acrylonitrile-butadiene copolymers, solid rubbers, fluoro-elastomers, polysiloxanes, acrylic rubber and polyethers. Solid preformed core-shell polymers are also so used.

The mechanism of toughening property improvement has been much studied over the past 20 years, especially with epoxide resin systems. There finally appears to be extensive

agreement that optimum performance requires close physical interaction between the continuous matrix and the separated discrete particles.

Work summarized by A. J. Kinlock, Rubber-Toughened

Plastics, Ed. C. K. Riew, Advances in Chemistry Series 222.

American Chemical Society, Washington, D.C. 1989, Bascomb, W. D. and Hunston, D. L . , Rubber-Toughened Plastics, Ed. C. K. Riew, Advances in Chemistry Series 222. American Chemical Society, Washington, D.C. 1989, Yee, A.F. , and Pearson, R.A. ., J. Mater. Sci . 1986, 21, 2462, and Levits, G. Rubber- Toughened Plastics, Ed. C.K. Riew, Advances in Chemistry

Series 222. American Chemical Society, Washington, D.C. 1989, indicates that plastic shear yielding in the continuous matrix is the main source of energy dissipation and increased

resistance to crack growth or generation of toughening. Some considerable energy dissipation occurs through particle cavitation and though such stress concentration initiates the shear-yield deformation in the matrix.

Symbols, designations and limitations used herein have the same meaning regardless of how applied unless stated to the contrary herein.

The Invention

It has been determined that a toughener for thermosetting polymers should have a certain solubility relationship with the thermosetting resin matrix that allows phase separation in the matrix resin. The toughener must also provide a certain modulus or rubberiness. Because water can act as a

plasticizer and cause reduction in T_g (for example, moisture in an otherwise dry film will lower the T_g from 250°C. to

175°C), and because in composite formation and adhesives one seeks to minimize moisture absorption, a toughener should possess a certain water resistance.

Generation of optimum toughness from the interdependence of matrix and second phase particle properties requires

careful selection of materials having the proper matching of solubility properties, before and during cure, and modulus, T_g, moisture sensitivity, thermal and hydrolytic stability, and a number of other processing factors. This invention takes such factors into account plus cost, and processing ease during toughener production, composite formulation and adhesive film and/or composite manufacture.

This invention relates to a linear polyurethane polymer containing phenolic hydroxyl functionality for reaction with a thermosetting resins comprising

• a linear polyurethane of recurring units containing

linear ester or ether moieties or a combination of ester and ether moieties

• which are interbonded through urethane groups and

• uriedo bonded phenolic hydroxyl-containing terminal

groups.

This invention relates to a linear polyurethane toughener polymer containing uriedo bonded phenolic hydroxyl-containing terminal groups of the formula:

wherein a and b are each 1, 2 or 3, n is at least 1, each X is a divalent organic radical containing at least two carbon atoms in which the N are bonded to different carbon atoms of X, R is an aliphatic polyester or polyalkylene oxide wherein

• the alkylene group of the polyalkylene oxide contains on

R° is an organic aromatic containing group in which the OH and N bonded to the R° group are bonded directly to different carbon atoms and the OH is bonded directly to an aromatic carbon atom. An improved version of the polymer of formula (I) is the polymer of formula (II).

wherein x and y are 0 or 1, R' is hydrogen or alkyl of 1 to about 3 carbon atoms, and R¹, R², R³ and R⁴ are hydrogen, nitro, halogen or alkyl of 1 to about 4 carbon atoms. In a preferred embodiment of formula (I), the carbons to which the OH and N are bonded are separated from each other by at least one aromatic carbon atom. In a more desirable embodiment, the invention relates to a toughener polymer of the formula:

In this embodiment, R₀₁ is a divalent organic group and c is 0 or 1. In a preferred embodiment of the invention, with

respect to the polymer of formula (II), x and y are each 1, R¹, R², R³ and R⁴ are hydrogen, a and b are 1 and n has a value such that the weight average molecular weight of the polymer is about 20,000 to about 120,000. Incorporating this

preferred embodiment in formula (III), R₀₁ is methylene or c is 0. In a further preferred embodiment of the invention, the polymer has the formula:

wherein n has a value such that the weight average molecular weight of the polymer is about 30,000 to about 110,000 and R is a polyalkylene oxide in which the alkylene groups thereof have an average value of about 3.5 to about 4.5 carbon atoms. A most preferred polymer of the invention has the formula:

wherein n has a value such that the weight average molecular weight of the polymer is about 35,000 to about 100,000 and f has a value of at least 1, preferably from 1 to about 70, more preferably from about 4 to about 55, and most preferably from about 6 to about 42. The terminal hydroxyl groups may be in the ortho, meta or para positions, preferably in the para position.

A preferred polyurethane is one having a molecular weight from about 20,000 to about 120,000, preferably about 30,000 to about 110,000, and most prefereably about 35,000 to about

100,000, formed by the reaction of a poly-1,4-butylene oxide diol having a molecular weight of from about 650 to about 5,000 with a stoichiometric excess of methylene

diphenyldiisocyanate capped by reaction with o, m or p-amino phenol.

The invention also relates to a thermosetting resin composition containing the polymer of the above formulae and a cured resin composition containing the polymer. In addition, the invention relates to adhesive compositions that contain the toughener polymer of the above formulae, and composites made of similar compositions. In addition, the invention relates to reaction products of the toughener polymer to revise its polymerization characteristics when used in epoxy resin compositions. In this respect, the polymer of the invention can be modified by a variety of reactions, such as: or

In particular, the invention relates to cured epoxy resin compositions in which the toughener described herein is used alone or in combination with other compositions to enhance the toughness of the epoxy resin composition. The invention contemplates the interreaction of the polymer of the invention with an epoxy group of an epoxy resin

This invention contemplates thermosetting resin

formulations that possess superior toughening properties by combining the toughener polyurethanes of the invention, as described by formulae I, II, III, IV and V, with other

toughener polymers, particularly those of the block and random copolymer types. As a result, resin formulations are

obtainable possessing synergistic enhancement of the

mechanical properties of the cured version of the resin formulation. Such enhancement is ascertainable from standard methods of toughness measurements, such as the floating roller peel test.

Detailed Description Of The Invention

The polymers of the invention are specially capped linear polyurethanes formed by the reaction of a diisocyanate of the formula O=C=N-X-N=C=O with an alkylene diol of the formula HO- R-OH in the molar ratio 1 ,

such that the resulting polymer equals the value of n as defined above, followed by the reaction with aminophenolic compounds. Diisocyanates suitable for use in the practice of the invention include the following:

The preferred polyisocyanates are TDI, i.e., the mixture of 80% 2, 4-tolylenediisocyanate and 20% 2,6- tolylenediisocyanate, or the individual monomer 2,4- tolylenediisocyanate (2,4-TDI) and 2, 6-tolylenediisocyanate (2.6-TDI) and MDI, i.e., 4,4'-diphenylmethylene diisocyanate and 3,3'-diphenyl-methylene diisocyanate, or the individual monomer 4 ,4'-diphenylmethylene diisocyanate (4,4'-MDI) or 3,3'- diphenylmethylene diisocyanate (3,3'-MDI).

Blocked isocyanates comprising any of the above

polyisocyanates reacted with a monofunctional hydroxy

containing compound may be used instead for making the linear polyurethane. The resultant blocked polyisocyanate is

unreactive towards hydroxyl compounds at room temperature but, at elevated temperatures, will function as an isocyanate to react with the hydroxyl compounds to form the linear polymer. For example, an adduct of tolylene diisocyanate and

trimethylolpropane is first prepared in solution, followed by the addition of phenol to block the remaining isocyanate groups. Illustrative of such a blocked polyisocyanate is a phenol blocked toluene diisocyanate in cellosolve acetate sold by Miles Chemical Co., as Mondur S. Such blocked isocyanates, when mixed with the diols, provide a thermoplastic linear polyurethane toughening resin that is compatible with

thermosetting resins, such as epoxy and polyester resins. The polyalkylene ether or oxide diol comprises a divalent alkylene oxide moiety wherein the alkylene groups contain, on average, greater than three carbon atoms and not greater than five carbon atoms. Typically, they are based on ethylene oxide, 1, 2-propylene oxide, 1,3-propylene oxide, 1,2-butylene oxide, 1,3-butylene oxide, 1,4-butylene oxide, 1,2-pentylene oxide, 1,3-pentylene oxide, 1,4-pentylene oxide, 1,5-pentylene oxide, 1,2-hexylene oxide, generally polymerized alone when the alkylene group contains greater than 3 carbon atoms, or as mixtures, so as to form an number average alkylene carbon content greater than about 3 and as high as about 5,

preferably greater than 3.5 and as high as about 4.5. Many types of alkylene oxide diols are available for urethane production but all of those that have an average alkylene below about 3.5 have too high water absorption properties for use in high performance adhesive applications. Such exclude the polyethylene oxide diol homo-oligomers and the

polypropylene oxide diol homo-oligomers from consideration in forming the polyurethane tougheners of the invention.

All of the polyalkylene oxide diols used in making the polyurethane tougheners of the invention are prepolymers of the alkylene oxide(s), created by the polymerization of the monomeric alkylene oxide. Such prepolymer formation as well as their reactions to form polyurethanes is notoriously well known. Of the prepolymers, a preferred one is based on the polymerization of 1,4-butylene oxide (i.e., tetrahydrofuran) to a molecular weight of from about 650 to about 5,000. Such prepolymers are commercially available from DuPont under the name Terathane®. Terathanes® range in molecular weights as low as about 650 to as high as about 2900, as well as

molecular weight versions of about 1000 and 2000. Higher and lower molecular weight versions are also available. Such prepolymers provide low water absorption, flexible molecular structure, hydrolytic stability, and commercial availability at a moderate cost. Terathanes® have the formula

HO(CH₂CH₂CH₂CH₂O)_tH where t has a value of about 8-9 to about 40, though higher and lower values are available, and such oligomers could be used in making the polyurethanes of the invention.

Terathanes® have been widely recommended for use in making polyurethanes by DuPont. For example, they have been recommended by DuPont for use in forming soft segments in polyurethanes. When used with TDI, DuPont advises that amines such as 4,4'-methylene-bis(2-chloroaniline) are favored as chain extenders or curatives. If 4.4'-MDI is the chain extender, DuPont advises that 1,4-butanediol is the favored chain extender. However, this invention does not rely on other monomers as chain extenders or curatives though chain extenders can be employed to raise the molecular weight of lower polyurethane prepolymers prior to the capping step in making the polyurethanes of the invention. An object of the invention is to produce a polyurethane of the appropriate molecular weight and with the appropriate terminal functional groups, to effect toughening of thermosetting resins.

The polyester diols useful in making the polyurethanes of the invention are based on the reaction products of an

aliphatic dicarboxylic acid derivative (such as the acid halide or ester) and an aliphatic diol derived from an

polyalkylene oxide diol such as an alkylene glycol of 2 to about 5 carbon atoms, or based on the reaction of ε-caprolactone with a starter organic diol. These polyester diols are commercially available materials. They are

typically less hydrolytically stable than the aforedefined polyalkylene oxide diols. Those that are desirable in the practice of the invention are those that possess low water absorption, flexible molecular structure, hydrolytic

stability, and commercial availability at a moderate cost.

The linear polyester resins may be reaction products of saturated and unsaturated aliphatic dicarboxylic acids, such as malonic acid, succinic acid, adipic acid, maleic acid, fumaric acid, hexahydro or tetrahydrophthalic acid, "dimer" acid (dimerized fatty acids), and their respected anhydrides (where chemically possible), acid halides, and esters, with organic diols. The polyester may include in the reaction a minor amount, typically not more than 20 mol %, preferably not more than 10 mol %, of the acid component of the polyester, of an aromatic dicarboxylic acid such as o-phthalic acid or anhydride, isophthalic acid, terephthalic acid, their

respected anhydrides (where chemically possible), acid

halides, and esters. In addition to the above polyesters one may also use dicyclopentadiene modified unsaturated polyesters like those described in U.S. Patent Nos. 3,986,922 and

3,883,612, so long as the polyester is linear. The organic diol employed to produce the polyester may include the

alkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, dipropylene glycol, diethylene glycol, neopentyl glycol, and the like, and the polyalkylene oxide glycols such as triglyme (b.p. 216°C), tetraglyme (b.p.

276°C), tripropylene glycol, tetrapropylene glycol, and the like.

Chain termination of the linear polyalkylene oxide or polyester polyurethanes is effected by reacting more than one mole of the diisocyanate for each mole of the polyalkylene oxide diol and/or polyester diol. The amount of the

stoichiometric excess of the diisocyanate will determine the degree of polymerization (n) of the polyurethane. A

stoichiometric amount of the diisocyanate to the diol is 1 mole of each. If the reaction is conducted under anhydrous conditions, using an excess of diisocyanate over the

stoichiometric amount results in a polymer that is chain terminated with isocyanato groups at each end. If any water is present in the polyurethane formation step, then

stoichiometry should take that into account, because water will generate more near-terminal residing urea, as well as terminating isocyanato groups appended thereto. The level of excess diisocyanate will determine the degree of

polymerization and thus determine the value of n in the above formulas. Such an isocyanato-terminated polymer is not a thermally or chemically stable polymer. This invention provides a mechanism by which a thermally and chemically stable functional polymer capable of operating as a toughener in thermosetting resins can be derived from the isocyanatoterminated polyurethane.

Aromatic isocyanates are much more reactive than

aliphatic isocyanates toward hydroxyl containing compounds. Their reaction with primary hydroxyl groups is much faster than with secondary hydroxyls. Tertiary hydroxyls are much less reactive with isocyanates. The ratio of reactivity with isocyanates of primary hydroxyl groups to secondary and tertiary groups is approximately 1/.3/.005. Phenolic hydroxyl groups are relatively unreactive with isocyanates and often require use of catalysts to get reasonable reaction rates at lower temperatures. Water is similar in reactivity with isocyanates to a secondary alcohol so methods of water removal or exclusion are needed in controlled reaction systems.

High molecular weight urethane polymers from 4,4'-MDI or mixed TDI and the Terathane polyethers can be readily

dissolved in various epoxide resins for formulation into tough adhesives. However, the residual terminal isocyanate groups of the polyurethane resin react during subsequent storage and after several days, the polyurethane resin gels and can not be dissolved in epoxide resins or even active solvents. Thus, the polyurethane has a limited out time and consequently limited commercial utility.

In initial work to provide stable termination for the isocyanate terminated polymers, epoxide oligomers containing secondary hydroxyl groups could be easily reacted to give storage stable polymers and thus conveniently containing added components often needed in practical adhesive formulations. Such epoxide oligomer terminated materials also contained epoxide groups which would be reacted into the adhesive systems.

Subsequent thermal stability tests, however, showed that the urethane linkages thus made from the secondary hydroxyl groups of the epoxide oligomers had reduced thermal stability. An example, summarized in Table 1 below, shows that the original MDI-Terathane polymers, isocyanate terminated, increased in peak molecular (GPC) weight from 55K - 65K to 120-130K when terminated with the epoxide oligomer Epon 1001 sold by Shell Chemical Company, Inc. Aging of the polymer at 150°C, rapidly, in several hours, lowered the peak molecular weight down again to the 55-65K of the original isocyanate terminated polymer (Table 1). It is thus apparent that the urethane groups resulting from isocyanate reaction with secondary hydroxyl groups have much poorer thermal stability than urethanes from primary hydroxyl groups such as present in the Terathane polyether components.

Chemicals suitable for use in termination of isocyanate functional polymers must react selectively with the residual isocyanate groups, be low in reactivity to the epoxide groups present (assuming than an epoxy diluent is used in making the polymer), form thermally and hydrolytically stable linkages, retain solubility in subsequently used resins, and provide functional groups selectively reactive with epoxides during subsequent curing reactions. As shown in Table 2, aromatic amine groups appear to have the reactivity needed for

reasonably rapid reaction with isocyanate groups. However, aliphatic amines are too reactive, react too rapidly with epoxide groups and leave products active in promoting epoxide resin advancement. Hydroxyl groups are too inactive.

Phenolic hydroxyl groups are too unreactive for this termination reaction but would be ideal components of a termination reaction by providing unreacted functionality that is appropriate for incorporation of the toughener materials in the subsequent adhesive cure reactions. Combining these two useful reactivities, aromatic amino and phenolic hydroxyl, as in aminophenolics, provides the stability and reactivity needed for chain termination and subsequent reactivity.

This is demonstrated in the following Table 2. Reactions with amines are generally fast. A rough approximation of the relative rates of reaction of various functional groups is listed below:

By selecting a hydroxy aromatic amino compound, where the hydroxy is a phenolic hydroxyl, and the amine is positioned so as to allow the hydroxyl group to be free for subsequent reaction, the polyurethane can be chain terminated in a way that allows it to be reacted with the thermosetting resin to produce a toughened composite or adhesive.

The hydroxy aromatic amino compounds is preferably a structure of the formula:

wherein the combination of Roo and R₀₂ is equivalent to R° and Roi defined above, and in particular, Roo may be a covalent bond or a divalent non-aromatic group such as alkylene, alkylidene, oxygen, carbonyl, sulfone, and the like, d is 0 or 1 and when it is 1, the hatched line designating a fused ring bond is nonexistent, and when d is 0, the hatched line may exist as a fused ring bond to R₀₂. R₀₂ is aryl, polyaryl, fused ring aryl, polyfused ring aryl, cycloalkyl and the like, and c is 0 or 1. When d is 1, c is 1, and when d is 0, c may be 0 or 1. R₀₃ is hydrogen, or alkyl of 1 to about 14 carbon atoms.

Illustrative examples of suitable amines are the following:

The aminophenols, p, m or o-aminophenol, prove to be effective terminating molecules for the isocyanato capped polyurethanes. Solubility or a low melting point gives the meta product some advantage but the p-aminophenol dissolves readily in the toughener polymer - epoxide reaction system at the temperatures generally used (80-120°C). The low molecular weight of these aminophenols (109.1) means that relatively small amounts can be used for termination, solubility is high, the termination reaction is rapid, governed mostly by the time required to get good dispersion in the high viscosity system. The powdered amino phenol can be added directly to the

reaction mixture or more desirably can be powdered, mixed with a small portion of the low oligomer epoxide resin diluent, discussed below, and then added. Measurement of the IR absorption ratio of the isocyanate group 2240 cm^-1 peak to the 2840 cm^-1 -CH peak can be used to ensure that termination is complete.

During the polymerization of diisocyanates with the hydroxy terminated alkylene oxide or polyester based

materials, high molecular weights are attained (~20K-~120K, more typically in the range of about 30K to about 100K). As a result, viscosities became very high and at rational reaction temperatures (~50-170°C, preferably from about 80°C. -120°C.) stirring in laboratory or production equipment can become difficult. Use of a solvent as a diluent (e.g.,

methylethylketone (MEK), tetrahydrofuran (THF), and the like) of the reactants and the reaction products, though usable in making the polymers of the invention, adds the problem of its subsequent removal with a concomitant increase in production cost. As part of this invention, advantage is taken of the very low reactivity of hydroxyl groups with epoxide groups (unless catalyzed) and also the low reactivity of isocyanate groups with epoxide groups (unless the complex formation of oxazolidone is deliberately forced). Therefore, oligomer-free and thus secondary hydroxyl-free, epoxide resins can be used as unreactive diluents during the polymer formation. Such epoxide resins are subsequently compatible with formulation needs in future adhesive systems. For this dilution during reaction, epoxides as free as possible from oligomers should be used. Shell's Epon® 825 (the diglycidyl ether of bisphenol A) has been successfully used as a diluent even although the small amount of oligomer present (5%) did show some reaction. At 1/1 ratio to total derived polymer, Epon® 825 gave polymer products easily stirred at needed production temperatures and at that level should meet most subsequent formulation needs. D.E.N.® 332 from Dow Chemical should also be suitable. The Bis F resins, such as Epiclon® 830S, if distilled to eliminate oligomers, could also be used.

Illustrative of suitable diluents are epoxy monomers and dimers of the following formula:

wherein R^a and R are each hydrogen, alkyl of 1-3 carbon atoms or phenyl, preferably alkyl such as methyl, and p has a value of 0 to <1, preferably less than about 0.2. Most preferably, p is equal to 0.

The reaction conditions for forming the polyurethane from the diisocyanate and the diol is a temperature of about 50°C. to about 200°C. with mixing in the presence of a diluent, such as a conventional solvent, as indicated above, or the reactive diluent comprising the epoxy monomeric resin indicated above. The reaction should be carried out in the absence of added water, and anhydrous conditions are preferred. Conditions that remove water from the reactants before reaction and during reaction are desirable. No special catalysts are needed to effect the reaction but a catalyst that does not adversely affect the reactions can be employed. Catalysts are needed in polymerization reactions using aliphatic

isocyanates.

Example 1

The reactor used in the experiment was a 30 gal. Meyers Stainless Steel, Triple Range Mixer. The materials reacted comprise -

The crystalline (m.pt. 30-43°C) Terathane® 2900 was melted in a 100°C. oven. It was added to Epon® 825 in the reactor. The mixture was heated to 110°C. and stirred under vacuum for 1 hour to remove traces of water in the raw materials. The mixture was then cooled to 93°C. and the vacuum was released using dry nitrogen. With good stirring and a dry nitrogen sweep, flake MDI was added to the reactor over a 10-minute period. No significant exotherm was noted during the addition of the MDI flakes. The flakes readily dissolved. With

continued stirring and a nitrogen purge, the reaction

temperature was raised to 110°C. over a 30-minute period and the reaction was continued at 110°C. Samples are taken at intervals (40 min.) to follow the progress of the

polymerization. The main peak shown by GPC (gel permeation chromatography) (THF, 1.5 ml/min, linear, 10⁴, 10³, 500A

columns, Nelson GPC software) increased as shown in Table 2. After the main peak molecular weight reached 60-90K (about 7 hours) and the residual isocyanate content (measured by the IR absorbance ratios of 2240/2840 cm^-1) (Table 3) reached a low consistent value, the reaction was terminated by addition of powdered p-aminophenol (suspended in the indicated amount of Epon 825). This method of termination leaves a phenolic group for reaction with epoxide resins during subsequent

condensation reactions or during cure of formulated systems. The reaction system was de-aired by stirring under vacuum and releasing the vacuum under nitrogen.

Example 2

Terathane® 2900, 50g (.0351 eq) was mixed with Epon 825, 50.0g, and reacted with MDI, 5.48g (0.0438 eq); MDI/Terathane® 2900 molar ratio, 5/4. The temperature was controlled at 100-115°C. After 4 hours, the peak molecular weight (GPC) had stabilized at 58-61K and the system had become very viscous.

Calculation of the excess isocyanate theoretically present, 0.0438 eq. MDI - .0351 eq Terathane® 2900 = .0087 eq. excess NCO; .0087 × 54.53 eq. wt . of p-aminophenol = 0.474g. of p-aminophenol to terminate. This amount of p-aminophenol powder was added and stirred into the reaction mixture, at 112°C. for 35 minutes. IR spectra showed no residual -NCO absorption at 2240 cm^-1.

Stability studies at 150°C, summarized in Table 1, shows high stability compared to the epoxide oligomer termination previously made. These aminophenol terminated polymers were storage stable and retained their solubility in epoxide resins over long periods at ambient temperatures.

Toughener Stability

Processing needs and subsequent formulation and adhesive production needs as well as final product environmental performance, require a significant level of thermal, oxidative and hydrolytic stability in the generated toughener. Results of exposure tests to determine such property limits are discussed below.

Thermal Stability

Heat aging of the MDI-Terathane® 2900 toughener product in Epon® 825 diluent at 150°C. showed only a minor reduction of the peak molecular weight (GPC analysis) out to at least 80 hours (Table 1). A moderate further reduction occurred out to the measured data at 175 hours. Several scaled-up batches showed the same results. Use of 1% antioxidant (Irganox®

1010) had at most a modest stabilizing effect. Aging at 150°C. done in the presence of air somewhat discolored the product but little acceleration of molecular weight loss was noticed. Several toughener products made from the aliphatic isocyanate (Desmodur® W, i.e., bis(4-isocyanatocyclohexyl)methane) showed lower retention of properties. Such aliphatic isocyanates were sluggish in their reaction with the primary hydroxyl terminated butylene oxide polymers and catalysts had to be used to attain molecular weights more easily attained using the aromatic diisocyanates. For these reasons, the aromatic diisocyanates are preferred in the practice of the invention.

Hydrolytic Stability

A thin layer (2 mm) of the MDI-Terathane® 2900 toughener in Epon® 825 diluent was exposed at 100% RH and 71.1°C. for an extended time (to 45 days) and showed only a moderate

reduction in the peak molecular weight (Table 4).

Toughener Interaction with Adhesive Formulation Components Frequently in adhesive formulation work, various epoxide resins, diphenols and other reactive components, such as functional tougheners, are reacted in the presence of

catalysts to form an intermediate molecular weight condensate often increasing the effectiveness of tougheners. Work by Yee, A. F. , and Pearson, R . A. , supra , demonstrates the

usefulness of this method of toughener appreciation. The temperature so used, in the range of 150°C, can have some effect on the toughener molecular weight but work in this area suggests that there is some interaction with the condensation reaction components. As shown in Table 5, aging at 150°C. in the presence of Epon® 1001, a diglycidyl ether of bisphenol A oligomer, representative of the epoxide oligomers (containing secondary hydroxyl groups) resulting from such condensation reactions, does moderately increase the rate of polymer molecular weight reduction. An even larger influence was noted when free bisphenol A was present during the aging.

These results suggest that an alternate procedure for introducing the toughener into the formulation would have advantages. Namely, preparation of the condensation reaction and then addition of the toughener under controlled

temperature and times to minimize such chemical interaction and temperature exposure. Such modified preparation methods have proved effective. The condensation reactions have been carried out at 150-160°C, and then the toughener and other resin components added at their 100-120°C temperatures resulting in potential drum out temperatures in the range of 130°C or lower with normal cooling times for drum quantities resulting in temperatures below 100°C in ten to twenty hours.

Such order of preparation has proved to be effective in generation of toughened adhesive film and no reduction in performance has been noted over the more conventional

preparative route. These resultant materials should have stabilities needed for the component mixing and fabrication of adhesive film products.

The typical thermosetting resin is an A-stage resin. In some cases, it may be desirable to utilize a B-stage resin but in the typical case, such is done in combination with an A- stage resin. Such B-stage resin will affect the viscosity of the resin formulation but they are not relied on to achieve the level of flow control for the most effective operation of the invention.

A preferred class of thermosetting resin in the practice of the invention are the epoxy resins. They are frequently based, in ter al ia , on one or more of diglycidyl ethers of bisphenol A (2,2-bis(4-hydroxyphenyl)propane) or sym-tris(4- hydroxyphenyl)propane, tris(4-hydroxyphenyl)methane, their polyepoxide condensation products, cycloaliphatic epoxides, epoxy-modified novolacs (phenol-formaldehyde resins) and the epoxides derived from the reaction of epichlorohydrin with aniline, o-, m- or p-aminophenol, and methylene dianiline.

The epoxy resins suitable in the practice of the

invention include the various established thermosetting epoxy resins conventionally employed in making prepregs, especially carbon and graphite fiber reinforced prepregs and adhesives. It is desirable that the epoxy resin be a low or lower

viscosity version to facilitate film formation. Illustrations of suitable epoxy resins include, e.g., one or more of

diglycidyl ethers of bisphenol A (2,2-bis(4-hydroxyphenyl)propane), such a those of the following formula:

or sym-tris(4-hydroxyphenyl)propane or tris(4-hydroxyphenyl)methane, their polyepoxide condensation

products, cycloaliphatic epoxides, epoxy-modified novolacs (phenol-formaldehyde resins) of the formula:

wherein n is 0-1.8, preferably 0.1-0.5 Other epoxy resins may be combined with the above epoxy resins or used alone. They include, e.g., 3,4-epoxy

cyclohexyl methyl-3,4-epoxy cyclohexane carboxylate, vinyl cyclohexene dioxide, 2-(3,4-epoxy cyclohexyl -5,5-spiro - 3,4 epoxy) cyclohexane - meta - dioxane, bis (3,4-epoxy

cyclohexyl) adipate, and the like.

The epoxy resins of the invention are combined with hardeners which cure the resin to a thermoset condition, The preferred hardeners are amine compounds, ranging from

dicyandiamide, to ureas, to aliphatic and aromatic amines A preferred class of. hardeners are the aromatic amines

encompassed by the formula:

Q is one or more of a divalent group such as -SO₂-, -O-, -RR'C-, -NH-, -CO-, -CONH-, -OCONH-, and the like, R and R' may each independently be one or more of hydrogen, phenyl, alkyl of 1 to about 4 carbon atoms, alkenyl of 2 to about 4 carbon atoms, fluorine, cycloalkyl of 3 to about 8 carbon atoms, and the like, x may be 0 or 1, y may be 0 or 1 and is 1 when x is 1, and z may be 0 or a positive integer, typically not greater than about 5.

Preferred hardeners are diamines of the formula:

Another preferred class of hardeners are the aliphatic amines such as the alkyleneamines. Illustrative of suitable alkyleneamines are the following:

Monoethanolamine Pentaethylenehexamine

Ethylenediamine Diaminoethylpiperazine

N-(2-aminoethyl)ethanolamine Piperazinoethylethylenediamine

Diethylenetriamine 4-Aminoethyltriethylenetetramine

Piperazine Tetraethylenepentamine

N-(2-aminoethyl)piperazine Aminoethylpiperazinoethylethylenediamine

Triethylenetetramine Piperazinoethyldiethylenetriamine

Tetraethylenepentamine

Another class of hardeners, but which can also be used as extender of the epoxy resin, are the higher molecular weight poly(oxyalkylene)- polyamines such as those of the following formulas :

The hardener may be a monoamine such as aniline, para- aminophenol, and alkylated versions of them.

A further class of desirable hardeners are the reaction products of dialkylamines, such as dimethylamine,

diethylamine, methylethylamine, di-n-propylamine, and the like, with a variety of mono and diisocyanates to form mono and diureas. Any of the polyisocyanates listed below may be so reacted for use as a hardener. Specific illustration of useful hardeners are those encompassed by the following formulas and descriptions:

where R is a monovalent organic group;

R' is alkyl, halo, alkoxy, and the

like; R" is methylene, isopropylidene, ethylidene, or a covalent bond; and a

is 0-4.

Preferred urea hardeners are those that are the reaction products of dimethylamine with mixtures of 80% 2,4-tolylenediisocyanate and 20% 2,6-tolylenediisocyanate, polymericisocyanate, p-chlorophenylisocyanate, 3,4- dichlorophenylisocyanate or phenylisocyanate.

The amount of the hardener employed is usually

stoichiometrically equivalent on the basis of one amine group per epoxy group in the resin though reduced amounts of hardener, to 50% of equivalency, can sometimes be usefully employed. If the epoxide is a triepoxide and the hardener is a diamine, then the molar ratio of hardener to epoxide would typically be about 2.5/3 or 0.83. A typical formulation would have a weight ratio of epoxy resin to hardener of about 3/2 to about 4/1. Where any of the hardeners serve primarily as extenders of the epoxide resin, then the amount of the

hardener in the typical case will be less than that generally employed for hardening the epoxide. Mixtures of the above hardeners and with other hardeners are within the

contemplation of this invention.

Other reactive resin systems include the various

thermosetting or thermosettable resins include the

bismaleimide (BMI), phenolic, polyester (especially the unsaturated polyester resins typically used in SMC

production), PMR-15 polyimide and acetylene terminated resins are also suitable.

Polyester resins usable as the thermosetting matrix resin, are typically reaction products of a dicarboxylic acid, acid halide or anhydride, with a polyhydric alcohol. The dicarboxylic acids or anhydrides that are employed to produce the polyester, either singly or in combination, include those that contain olefinic unsaturation, preferably wherein the olefinic unsaturation is alpha, beta- to at least one of the carboxylic acid groups, saturated aliphatic, heteroaliphatic and aromatic polycarboxyiic acids, and the like. Such acids include maleic acid or anhydride, fumaric acid, methyl maleic acid, and itaconic acid (maleic acid or anhydride and fumaric acid are the most widely used commercially), saturated and/or aromatic dicarboxylic acids or anhydrides such as phthalic acid or anhydride, terephthalic acid, hexahydrophthalic acid or anhydride, adipic acid, isophthalic acid, and "dimer" acid (i.e., dimerized fatty acids). They may be cured by providing a polymerization initiator and low viscosity crosslinking monomers in the formulation. Where the resin is a unsaturated polyester or vinyl ester, it is preferred that the monomers contain ethylenic unsaturation such that the monomer is copolymerizable with the polyester and terminally unsaturated vinyl ester resins. Useful monomers include monostyrene, alkyl acrylates and methacrylates such as C_1-12 alkyl acrylates and methacrylates, substituted styrenes such as α-methyl styrene, α-chlorostyrene, 4-methylstyrene, and the like, divinylbenzene, acrylonitrile, methacrylonitrile, and the like. Styrene is the preferred monomer in commercial practice today, although others can be used. Suitable polymerization initiators include t-butyl hydroperoxide, t-butyl perbenzoate, benzoyl peroxide, cumene hydroperoxide, methyl ethyl ketone peroxide, and others known to the art. The polymerization initiator is employed in a catalytically effective amount, such as from about 0.3 to about 2 to 3 weight percent, based on the weight of polyester and the crosslinking monomer.

When desired, a thickening agent can also be employed in the polyester thermosetting compositions. Such materials are known in the art, and include the oxides and hydroxides of the metals of Group I, II and III of the Periodic Table .

Illustrative examples of thickening agents include magnesium oxide, calcium oxide, calcium hydroxide, zinc oxide, barium oxide, magnesium hydroxide and the like, including mixtures of the same. Thickening agents are normally employed in

proportions of from about 0.1 to about 6 weight percent, based upon weight of the polyester resin and crosslinking monomer. Particularly desirable are the polyester systems described in U.S. Patent 4,525,498 and U.S. Patent 4,374,215, in which there is incorporated a low profile additive composition containing a thermosetting unsaturated polyester, a

thermoplastic polymer additive that controls shrinkage, and an ethylenically unsaturated monomer. The polyurethanes of the invention offer the capability of toughening the polyester while enhancing shrinkage reduction of the resin on cure.

The toughener may be used alone or in combination with other polymer types to enhance, in many instances

synergistically, the toughness of the thermosetting resin system. Particular elastomer-type polymers that provide discrete elastomer phases (second phases) in the thermosetting resin matrix may be used in combination with the tougheners of the invention. Such types of tougheners, as pointed out above, contribute enhanced toughening properties to the resin system. Certain of these material may reduce, to some finite degree, the crosslinking density of the thermoset resin (C-stage). Many of these materials introduce very favorable properties to the resulting thermoset resin. For example, a particularly desirable material for this purpose, is an

elastomeric polymer containing soft and hard segments, the hard segments acting like or forming on processing,

crosslinking of the elastomeric type. Some of these

elastomeric types contain functional end groups which allow it to couple with complementary functional monomers or polymers to form the desired elastomer in situ of the thermosetting resin and toughen the cured resin.

One class of suitable elastomer-type thermosplastic ABS (acrylonitrile-1,4-butadiene-styrene) block copolymers that are typically used as modifiers of other resin systems. They are characterized as having a wide range of properties though the preferred systems of the invention utilize copolymers that are high rubber types that, when compared to other copolymers of this type, have a relatively low tensile strength, low tensile modulus, higher impact resistance, low hardness and heat deflection temperature. Another elastomer that is found desirable are the carboxyl and amine terminated liquid

butadiene acrylonitrile copolymers. Such copolymers may contain pendant carboxyl groups in the interior of the polymer structure through the inclusion of methacrylic or acrylic acid in the polymerization or through the hydrolysis of some of the pendant nitrile units. Such polymers react with the epoxy resin and as a result, the epoxy forms the hard segment generating the elastomer properties. This class of toughener can be effectively used in combination with the polyurethane toughener of the inventions to synergistically enhance the toughness of the resin system.

Another class of block thermoplastic elastomers are

Kraton™, available from Shell Chemical Company. These thermoplastic rubber polymers possess usable thermoplastic properties. They can be softened and they flow under heat and pressure. They then recover their structures on cooling. The chemical make-up are of three discrete blocks of the linear or A-B-A type. They are available as styrene-butadiene-styrene (S-B-S) block copolymers, styrene-isoprene-styrene (S-B-S) block copolymers and styrene-ethylene/butylene-styrene (S-EB-S) block copolymers. They are characterized by styrene polymer endblocks and an elastomeric midblock. After

processing, the polystyrene endblocks physically crosslink, locking the rubber network in place. This physical

crosslinking is reversible on heating.

Another series of the Kraton™ thermoplastic rubbers are the diblock polymers in which one block is a hard

thermoplastic and the other is a saturated soft elastomer.

Illustrative of this series is Kraton™ G 1701, a diblock polymer of a hard polystyrene block and a saturated, soft poly(ethylene-propylene) block.

Other rubbers or elastomers include: (a) homopolymers or copolymers of conjugated dienes having a weight average molecular weight of 30,000 to 400,000 or higher as described in U.S. Pat. No. 4,020,036, in which the conjugated dienes contain from 4-12 carbon atoms per molecule such as 1,3- butadiene, isoprene, and the like; (b) epihalohydrin

homopolymers, a copolymer of two or more epihalohydrin

monomer, or a copolymer of an epihalohydrin monomer(s) with an oxide monomer(s) having a number average molecular weight (M_n) which varies from about 800 to about 50,000, as described in U.S. Pat. No. 4,101,604; (c) chloroprene polymers including homopolymers of chloroprene and copolymers of chloroprene with sulfur and/or with at least one copolymerizable organic monomer wherein chloroprene constitutes at least 50 weight percent of the organic monomer make-up of the copolymer as described in U.S. Pat. No. 4,161,471; (d) hydrocarbon polymers including ethylene/propylene dipolymers and copolymers of ethylene/propylene and at least one nonconjugated diene, such as ethylene/propylene/hexadiene/norborn- adiene, as described in U.S. Pat. No. 4,161,471; (e) conjugated diene butyl

elastomers, such as copolymers consisting of from 85 to 99.5% by weight of a C₄ -C₇ isolefin combined with 15 to 0.5% by weight of a conjugated multi-olefin having 4 to 14 carbon atoms, copolymers of isobutylene and isoprene where a major portion of the isoprene units combined therein have conjugated diene unsaturation as described in U.S. Pat. No. 4,160,759.

Specific illustrations of suitable elastomeric polymers are the following:

1. Hycar™ CTBN liquid reactive rubbers, carboxyl terminated butadiene-acrylonitrile copolymers sold by B. F. Goodrich. 2. Hycar™ CTBNX, similar to CTBN except that they contain internal pendant carboxyl groups, also supplied by B. F.

Goodrich.

3. Hycar™ ATBN, amine terminated butadiene-acrylonitrile copolymers sold by B. F. Goodrich.

4. K 1102-28:72 styrene :butadiene linear SBS polymer, available from Shell Chemical Company under the registered trademark "Kraton" 1102.

5. KDX 1118-30:70 styrene :butadiene copolymer containing 20% SBS triblock and 80% SB diblock, available from Shell Chemical

Company under the registered trademark "Kraton" DX 1118.

6. KG 1657-14:86 stryene : ethylene-butylene : styrene copolymer available from Shell Chemical Company under the registered trademark "Kraton" G1657.

7. S 840 A-Stereospecific 43:57 styrene-butadiene SB rubber available from Firestone Synthetic Rubber & Latex Company under the registered trademark "Stereon" 840A.

8. SBR 1006-random 23.5:76.5 styrene : butadiene SB block copolymer rubber available from Goodrich Chemical Company under the registered trademark "Ameripol" 1006.

9. SBR 1502-Random 23.5:77.5 styrene :butadiene rubber

available from Hules Mexicanos, or from Goodrich Rubber

Company as "Ameripol" 1502.

10. Cycolac™ Blendex modifier resins (e.g., 305, 310, 336, 338 and 405) - ABS polymers sold by Borg-Warner Chemicals, Inc.

Different varieties are available and their suitability depends on the properties sought.

The polyurethane toughener of the invention is

incorporated into the thermosetting resin formulation in an amount sufficient to add toughness to the resultant cured resin. Conventional blending equipment and manufacturing procedures can be used in making such a resin formulation.

That amount can be as low as two weight percent or less based on the weight of the resin formulation, to as high as thirty- five weight percent or more based on the weight of the resin formulation. Frequently the toughener of the invention is used in combination with other tougheners, such as the addition polymer types listed above. Such combinations have been found to provide especially superior mechanical

properties to the formulation as noted below. A particularly desirable toughening addition polymer resin is the core-shell particulate ABS types. Frequently, the amount of the

polyurethane toughener of the invention is used in amounts substantially equivalent to that of the other type of

toughener. For example, one may use from about 3 to about 15 weight percent of the toughener of the invention with about 4 to about 20 weight percent by weight of the other type of toughener, basis total weight of the formulation. In the case of an epoxy resin adhesive formualtion, from about 3.5 to 10 weight percent of the polyurethane toughener of the invention can be used with about 5 to 15 percent of a high rubber content core-shell ABS toughener, with a total system weight per epoxy (WPE) of over 400 WPE . Such a system may use a dicyandiamide curing agent in the range of about 50 to 75% of stoichiometry. Urea catalyst or amine catalyst is desirable when the catalysis is initiated below about 121°C. The epoxy resin may be low molecular epoxides such as Epon® 826 and Epon® 828 sold by Shell Chemicals. Bisphenol A may be

provided to increase the molecular weight of the formulation through an addition reaction with the epoxy groups.

The order of addition of the toughener to the epoxy formulation may be critical to control adverse aging. If the epoxy resin is chain extended during the formulation because chain extension benefits properties, then it is desirable to complete chain extension reactions before introducing the toughener of the invention which on cure will chain extend the epoxy resin. Moreover, this prevents reactions between the chain extenders and the toughener of the invention, which reactions could adversely affect the molecular integrity of the toughener. This could occur if there is employed another toughener which possesses functionality complementary to that of the polyurethane toughener of the invention.

A typical formulation incorporating the toughener of the invention includes the following: Part A: Mixed in the following order:

Part A may be stored in drums at ambient temperature until needed to make a formulated product such as an adhesive film. Part B:

Part A and Part B may be metered through a mixing device in exact proportions and the resultant resin/curatives are spread to a thin film by the use two moving rolls between two release papers. A bondline control fabric may or may not be added to the adhesive. The adhesive film is wound onto itself to produce a continuous product typically 350 to 500 foot in length

The polyurethane toughener of the invention has been found to function synergistically with a core-shell ABS particulate toughener. The toughener when used alone provides a good level of toughness when used in an epoxy resin

formulation as the sole toughener, but provides large

increases in performance when used in combination with an ABS type of toughener as shown in Table 6.

Numerous tests can be run to measure toughness. A preferred method for measuring toughness is the floating roller peel test (sometimes called "Bell Peel"). Bell Peel is preferred because of the ease in fabrication of the test specimen for the test and also because the test is the most sensitive to changes in toughness of an adhesive film. As a relative measure, up to 60 pli at room temperature can be achieved with most common tougheners: nitrile rubbers, butyl rubbers, and polyethers. Increasing this value to 80 pli is a large increase in strength. To describe the relative

differences, the two adherands can be pulled apart by an average male with moderate effort at the 60 pli strength. At 80 pli, a person cannot initiate failure and needs pliers to separate the two adherands with great effort.

Mechanical Performance Comparisons:

A study was performed to determine mechanical performance verses state of the art competition with respect to film adhesives. It was found that the toughener provided the following benefits in an epoxy resin film adhesive formulation over state of the art commercial epoxy resin film adhesive formulations :

• Increased toughness without the loss of shear strength

• Increased performance after hot/wet conditioning

• Increased performance after out-time exposure

• Flow control

• Decreased water absorption

Claims

CLAIMS:

1. A linear polyurethane containing phenolic hydroxyl functionality for reaction with a thermosetting resins comprising

a linear polyurethane of recurring units containing linear ester or ether moieties or a combination of ester and ether moieties

which are interbonded through urethane groups and have uriedo bonded phenolic hydroxyl-containing terminal groups.

2. The linear polyurethane containing phenolic hydroxyl functionality of claim 1 having the formula:

• the alkylene group of the polyalkylene oxide contains on

R° is an organic aromatic containing group in which the OH and N bonded to the R° group are bonded directly to different carbon atoms and the OH is bonded directly to an aromatic containing carbon atom.

3. The linear polyurethane containing phenolic hydroxyl functionality of claim 2 having the formula:

wherein x and y are 0 or 1, R' is hydrogen or alkyl of 1 to about 3 carbon atoms, and R¹, R², R³ and R⁴ are hydrogen, nitro, halogen or alkyl of 1 to about 4 carbon atoms.

4. The linear polyurethane containing phenolic hydroxyl functionality of claim 1 wherein the carbons to which the OH and N are bonded are separated from each other by at least one aromatic carbon atom.

5. The linear polyurethane polymer containing phenolic hydroxyl functionality of claim 3 having the formula:

wherein R₀₁ is a divalent organic group and c is 0 or 1

6. The linear polyurethane containing phenolic hydroxyl functionality of claim 3 wherein x and y are each 1, R¹, R², R³ and R⁴ are hydrogen, a and b are 1 and n has a value such that the weight average molecular weight of the polymer is about 20,000 to about 120,000.

7. The linear polyurethane polymer containing phenolic hydroxyl functionality of claim 5 wherein R₀₁ is methylene or c is 0.

8. The linear polyurethane polymer containing phenolic hydroxyl functionality of claim 6 having the formula:

wherein n has a value such that the weight average molecular weight of the polymer is about 30,000 to about 100,000 and R is a polyalkylene oxide in which the alkylene groups thereof have an average value of about 3.5 to about 4.5 carbon atoms and a molecular weight of 300 to 5,000.

9. The linear polyurethane containing phenolic hydroxyl functionality of claim 8 having the formula:

wherein n has a value such that the weight average molecular weight of the polymer is about 35,000 to about 100,000 and f has a value of at least 1.

10. The linear polyurethane of claim 9 wherein f has a value from 1 to about 70.

11. The linear polyurethane of claim 10 wherein f has a value from about 4 to about 55.

12. The linear polyurethane of claim 11 wherein f has a value from about 6 to about 41.

13. The linear polyurethane of claim 9 wherein the terminal hydroxyl groups are in the para position.

14. A thermosetting resin composition containing the polymer of claim 1.

15. A thermosetting resin composition containing the polymer of claim 2.

16. A thermosetting resin composition containing the polymer of claim 3.

17. A thermosetting resin composition containing the polymer of claim 4.

18. A thermosetting resin composition containing the polymer of claim 5.

19. A thermosetting resin composition containing the polymer of claim 6.

20. A thermosetting resin composition containing the polymer of claim 7.

21. A thermosetting resin composition containing the polymer of claim 8.

22. A thermosetting resin composition containing the polymer of claim 9.

23. A thermosetting resin composition containing the polymer of claim 10.

24. A thermosetting resin composition containing the polymer of claim 11.

25. A thermosetting resin composition containing the polymer of claim 12.

26. A thermosetting resin composition containing the polymer of claim 13.

27. An adhesive comprising the thermosetting composition of claim 14.

28. An adhesive comprising the thermosetting composition of claim 15.

29. An adhesive comprising the thermosetting composition of claim 16.

30. An adhesive comprising the thermosetting composition of claim 17.

31. An adhesive comprising the thermosetting composition of claim 18.

32. An adhesive comprising the thermosetting composition of claim 19.

33. An adhesive comprising the thermosetting composition of claim 20.

34. An adhesive comprising the thermosetting composition of claim 21.

35. An adhesive comprising the thermosetting composition of claim 22.

36. An adhesive comprising the thermosetting composition of claim 23.

37. An adhesive comprising the thermosetting composition of claim 24.

38. An adhesive comprising the thermosetting composition of claim 25.

39. An adhesive comprising the thermosetting composition of claim 26.

40. The thermosetting resin composition of claim 14 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

41. The thermosetting resin composition of claim 15 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

42. The thermosetting resin composition of claim 16 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

43. The thermosetting resin composition of claim 17 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

44. The thermosetting resin composition of claim 18 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

45. The thermosetting resin composition of claim 19 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

46. The thermosetting resin composition of claim 20 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

47. The thermosetting resin composition of claim 21 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

48. The thermosetting resin composition of claim 22 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

49. The thermosetting resin composition of claim 23 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

50. The thermosetting resin composition of claim 24 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

51. The thermosetting resin composition of claim 25 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

52. The thermosetting resin composition of claim 26 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

53. The adhesive composition of claim 27 where the

thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

54. The adhesive composition of claim 27 where the

55. The adhesive composition of claim 29 where the

56. The adhesive composition of claim 30 where the

57. The adhesive composition of claim 31 where the

58. The adhesive composition of claim 32 where the

59. The adhesive composition of claim 33 where the

60. The adhesive composition of claim 34 where the

61. The adhesive composition of claim 35 where the

62. The adhesive composition of claim 36 where the

63. A thermosetting resin composition containing the polymer of claim 1 and another resin toughener.

64. A thermosetting resin composition containing the polymer of claim 2 and another resin toughener.

65. A thermosetting resin composition containing the polymer of claim 3 and another resin toughener.

66. A thermosetting resin composition containing the polymer of claim 4 and another resin toughener.

67. A thermosetting resin composition containing the polymer of claim 5 and another resin toughener.

68. A thermosetting resin composition containing the polymer of claim 6 and another resin toughener.

69. A thermosetting resin composition containing the polymer of claim 7 and another resin toughener.

70. A thermosetting resin composition containing the

polymer of claim 8 and another resin toughener.

71. A thermosetting resin composition containing the

polymer of claim 9 and another resin toughener.

72. A thermosetting resin composition containing the

polymer of claim 10 and another resin toughener.

73. A thermosetting resin composition containing the polymer of claim 11 and another resin toughener.

74. A thermosetting resin composition containing the polymer of claim 12 and another resin toughener.

75. A thermosetting resin composition containing the polymer of claim 13 and another resin toughener.

76. The thermosetting resin composition of claim 63 wherein the other resin toughener is an ABS copolymer.

77. The thermosetting resin composition of claim 64 wherein the other resin toughener is an ABS copolymer.

78. The thermosetting resin composition of claim 65 wherein the other resin toughener is an ABS copolymer.

79. The thermosetting resin composition of claim 66 wherein the other resin toughener is an ABS copolymer.

80. The thermosetting resin composition of claim 67 wherein the other resin toughener is an ABS copolymer.

81. The thermosetting resin composition of claim 68 wherein the other resin toughener is an ABS copolymer.

82. The thermosetting resin composition of claim 69 wherein the other resin toughener is an ABS copolymer.

83. The thermosetting resin composition of claim 70 wherein the other resin toughener is an ABS copolymer.

84. The thermosetting resin composition of claim 71 wherein the other resin toughener is an ABS copolymer.

85. The thermosetting resin composition of claim 72 wherein the other resin toughener is an ABS copolymer.

86. The thermosetting resin composition of claim 73 wherein the other resin toughener is an ABS copolymer.

87. The thermosetting resin composition of claim 74 wherein the other resin toughener is an ABS copolymer.

88. The thermosetting resin composition of claim 75 wherein the other resin toughener is an ABS copolymer.

89. The adhesive composition of claim 53 wherein the thermosetting resin is an epoxy resin, the polyurethane toughener is a poly 1,4-butyleneoxide diol reacted with a stoichiometric excess of methylene diphenyl diisocyanate and capped with one or more of o, m and p-aminophenol.

90. The adhesive composition of claim 89 wherein the epoxy resin is a glycidyl ether of bisphenol A.

91. A polyurethane having a molecular weight from about

20,000 to about 120,000 by the reaction of a poly-1, 4-butylene oxide diols having a molecular weight of from about 650 to about 5,000 with a stoichiometric excess of methylene

diphenyldiisocyanate capped by reaction with one or more of ortho, meta and para-amino phenol.

92. The polyurethane of claim 91 wherein the poly-1,4-butylene oxide diol has the formula HO(CH₂CH₂CH₂CH₂O)_tH in which t has a value of about 6 to about 42.

AMENDED CLAIMS

[received by the International Bureau on 6 May 1996 (06.05.96);

original claims 1-92 replaced by amended

claims 1-81 (10 pages)]

1.A linear polyurethane containing phenolic hydroxyl functionality for reaction with a thermosetting resins having the formula:

wherein a and b are each 1, 2 or 3, n is at least 1, x and y are 0 or 1, R is an aliphatic polyester or polyalkylene oxide wherein the aliphatic polyester is a polyester of an alkylene diol and an aliphatic carboxylic acid, or a polycaprolactone polyol, and the alkylene group of the polyalkylene oxide contains on average greater than three carbon atoms and not greater than five carbon atoms, R' is hydrogen or alkyl of 1 to about 3 carbon atoms, and R¹, R¹, R³ and R⁴ are hydrogen, nitro, halogen or alkyl of 1 to about 4 carbon atoms and R° is an organic aromatic containing group in which the OH and N bonded to the R^o group are bonded directly to different carbon atoms and the OH is bonded directly to an aromatic containing carbon atom. 2. The linear polyurethane containing phenolic hydroxyl functionality of claim 1 wherein the carbons of the phenolic terminal groups to which the OH and N are bonded are separated from each other by at least one aromatic carbon atom. 3. The linear polyurethane polymer containing phenolic hydroxyl functionality of claim 1 having the formula :

wherein R_0l is a divalent organic group and c is 0 or 1.

4. The linear polyurethane containing phenolic hydroxyl functionality of claim 3 wherein x and y are each 1, R¹ R², R³ and R⁴ are hydrogen, a and b are 1 and n has a value such that the weight average molecular weight of the polymer is about 20,000 to about 120,000.

5. The linear polyurethane polymer containing phenolic hydroxyl functionality of claim 1 wherein R₀₁ is methylene or c is 0.

6. The linear polyurethane polymer containing phenolic hydroxyl functionality of claim 5 having the formula:

7. The linear polyurethane containing phenolic hydroxyl functionality of claim 6 having the formula;

8. The linear polyurethane of claim 7 wherein f has a value from 1 to about 70.

9. The linear polyurethane of claim 8 wherein £ has a value from about 4 to about 55.

10. The linear polyurethane of claim 9 wherein f has a value from about 6 to about 41. 11. The linear polyurethane of claim 9 wherein the terminal hydroxyl groups are in the para position.

12. A thermosetting resin composition containing the polymer of claim 1.

13. A thermosetting resin composition containing the polymer of claim 2.

14. A thermosetting resin composition containing the polymer of claim 3.

15. A thermosetting resin composition containing the polymer of claim 4. 16. A thermosetting resin composition containing the polymer of claim 5.

17. A thermosetting resin composition containing the polymer of claim 6.

18. A thermosetting resin composition containing the polymer of claim 7.

19. A thermosetting resin composition containing the polymer of claim 8.

20. A thermosetting resin composition containing the polymer of claim 9.

21. A thermosetting resin composition containing the polymer of claim 10.

22. A thermosetting resin composition containing the polymer of claim 11.

23. An adhesive comprising the thermosetting composition of claim 12.

24. An adhesive comprising the thermosetting composition of claim 13.

25. An adhesive comprising the thermosetting composition of claim 14.

26. An adhesive comprising the thermosetting composition of claim 15.

27. An adhesive comprising the thermosetting composition of claim 16. 28. An adhesive comprising the thermosetting composition of claim 17.

29. An adhesive comprising the thermosetting composition of claim 18.

30. An adhesive comprising the thermosetting composition of claim 19.

31. An adhesive comprising the thermosetting composition of claim 20.

32. An adhesive comprising the thermosetting composition of claim 21. 33. An adhesive comprising the thezmosetting composition of claim 22.

34. The thermosetting resin composition of claim 12 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

35. The thermosetting resin composition of claim 13 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

36. The thermosetting resin composition of claim 14 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

37. The thermosetting resin composition of claim 15 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

38. The thermosetting resin composition of claim 16 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

39. The thermosetting resin composition of claim 17 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

40. The thermosetting resin composition of claim 18 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

41. The thermosetting resin composition of claim 19 wherein the thermosetting rssin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

42. The thermosetting resin composition of claim 20 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

43. The thermosetting resin composition of claim 21 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

44. The thermosetting resin composition of claim 22 wherein the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

45. The adhesive composition of claim 23 where the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins. 46. The adhesive composition of claim 24 where the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

47. The adhesive composition of claim 25 where the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

48. The adhesive composition of claim 26 where the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins. 49. The adhesive composition of claim 27 where the thβrmosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

50. The adhesive composition of claim 28 where the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

51. The adhesive composition of claim 29 where the thermosetting resin ie selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

52. The adhesive composition of claim 30 where the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

53. The adhesive composition of claim 31 where the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins. 54. The adhesive composition of claim 32 where the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-15 polyimide and acetylene terminated resins.

55. The adhesive composition of claim 33 where the thermosetting resin is selected from the group consisting of epoxy, bismaleimide, phenolic, polyester, PMR-1S polyimide and acetylene terminated rssins .

56. A thermosetting resin composition containing the polyurethane of claim 1 and another resin toughener.

57. A thermosetting resin composition containing the polyurethane of claim 2 and another resin toughener. 58. A thermosetting resin composition containing the polyurethane of claim 3 and another resin toughener.

59. A thermosetting resin composition containing the polyurethane of claim 4 and another resin toughener.

60. A thermosetting reein composition containing the polyurethane of claim 5 and another resin toughener.

61. A thermosetting resin composition containing the polyurethane of claim 6 and another resin toughener.

62. A thermosetting resin composition containing the polyurethane of claim 7 and another resin toughener. 63. A thermosetting resin composition containing the polyurethane of claim 8 and another resin toughener.

64. A thermosetting resin composition containing the polyurethane of claim 9 and another resin toughener.

6b. A thermosetting resin composition containing the polyurethane of claim 10 and another resin toughener.

66. A thermosetting resin composition containing the polyurethane of claim 11 and another resin toughener. 67. The thermosetting resin composition of claim 56 wherein the other resin toughener is an ABS copolymer.

68. The thermosetting resin composition of claim 57 wherein the other resin toughener is an ABS copolymer.

69. The thermosetting resin composition of claim 58 wherein the other resin toughener is an ABS copolymer.

70. The thermosetting resin composition of claim 59 wherein the other resin toughener is an ABS copolymer. 71. The thermosetting resin composition of claim 60 wherein the other resin toughener is an AES copolymer.

72. The thermosetting resin composition of claim 61 wherein the other resin toughener is an ABS copolymer.

73. The thermosetting resin composition of claim 62 wherein the other resin toughener is an ABS copolymer.

74. The thermosetting resin composition of claim 63 wherein the other resin toughener is an ABS copolymer.

75. The thermosetting resin composition of claim 64 wherein the other resin toughener is an ABS copolymer. 76. The thermosetting resin composition of claim 65 wherein the other resin toughener is an ABS copolymer.

77. The thermosetting resin composition of claim 66 wherein the other resin toughener is an ABS copolymer.

78. The adhesive composition of claim 53 wherein the thermosetting resin is an epoxy resin, the polyurethane toughener is a poly 1,4-butyleneoxide diol reacted with a stoichiometric excess of methylene diphenyl diisocyanate and capped with one or more of o, m and p-aminophenol. 79. The adhesive composition of claim 78 wherein the epoxy resin is a glycidyl ether of bisphenol A.

80. A polyurethane having a molecular weight from about 20,000 to about 120,000 by the reaction of a poly- 1,4-butylene oxide diol having a weight average molecular weight of from about 650 to about 5,000 with a stoichiometric excess of methylene diphenyldiisocyanate terminated by reaction with at least one of ortho, meta and para-amino phenol.

81. The polyurethane of claim 80 wherein the poly1,4-butylene oxide diol has the formula HO(CH₂CH₂CH₂CH₂O)_tH in which t has a value of about 6 to about 42.