Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
  • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
  • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
  • C08G59/50—Amines
  • C08G59/504—Amines containing an atom other than nitrogen belonging to the amine group, carbon and hydrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/22—Polysiloxanes containing silicon bound to organic groups containing atoms other than carbon, hydrogen and oxygen
  • C08G77/26—Polysiloxanes containing silicon bound to organic groups containing atoms other than carbon, hydrogen and oxygen nitrogen-containing groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
  • C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
  • C08L79/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
  • C08L79/085—Unsaturated polyimide precursors
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31511—Of epoxy ether
  • Y10T428/31515—As intermediate layer
  • Y10T428/31518—Next to glass or quartz
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31511—Of epoxy ether
  • Y10T428/31515—As intermediate layer
  • Y10T428/31522—Next to metal
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31511—Of epoxy ether
  • Y10T428/31529—Next to metal
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31652—Of asbestos
  • Y10T428/31663—As siloxane, silicone or silane
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31678—Of metal
  • Y10T428/31681—Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31721—Of polyimide

Definitions

• the subject invention relates to thermosetting resin systems which contain certain secondary amine-terminated siloxane modifiers.
• the modified resins find uses as heat-­curable matrix resins in fiber-reinforced prepregs, as lam­inating films, and as structural adhesives.
• thermosetting resin systems contain a variety of heat-curable resins. Among these are epoxy resins, maleimide-group-containing resins, and the cyanate resins. All these resins are noted for their high tensile and compressive strengths and their ability to retain these properties at elevated temperatures, and all find extensive use in the aerospace and transportation industries. Other thermosetting systems which may be useful at lower temperatures or for specific applications include the polyurethanes, polyureas, polyacrylics, and unsaturated polyesters.
• piperazinyl functionalized polysiloxanes involves reaction of 2-aminoethylpiperazine with a previously synthesized carboxy-terminated polysiloxane to form the bis(2-piperazinyl ethyl amide) of the polysiloxane:
• a second approach is to react a large excess (to avoid polymer formation) of piperazine with a bis-epoxy polysiloxane, producing a bis(2-hydroxy-3-piperazinyl) poly­siloxane: This method, of course, requires prior preparation of the epoxy-functional polysiloxane.
• secondary amine-functionalized organosilicones may be used to modify a wide variety of thermosetting resin systems. These secondary amine-functionalized organosilicones may be used as reactive modifiers in any resin system which contains chemical groups which are reactive towards secondary amino groups. Alternatively, the secondary amine-functionalized organosili­cones may be prereacted with a monomeric, oligomeric, or polymeric reagent to form a "prereact" which is compatible but not necessarily reactive with the primary resin. Such modified resins display considerably enhanced toughness while main­taining their elevated temperature performance. Adhesives formulated with such modifiers show surprisingly enhanced lap shear strengths.
• modifiers may be readily prepared in quanti­tative or nearly quantitative yields, by reacting a secondary N-allylamine corresponding to the formula: or an analogous secondary N-( ⁇ -butenyl)- or N-( ⁇ -pentenyl)amine with an Si-H functional organosilicone, preferably a 1,1,3,3-­tetrasubstituted disiloxane or silane functional persubstituted polysiloxane, in the presence of a suitable catalyst.
• Si-H functional organosilicone preferably a 1,1,3,3-­tetrasubstituted disiloxane or silane functional persubstituted polysiloxane
• R1 may be individually selected from the group consisting of alkyl, preferably C1-C12 lower alkyl; alkoxy, preferably C1-C12 lower alkoxy; acetoxy; cyanoalkyl; halogen­ated alkyl; and substituted or unsubstituted cycloalkyl, aryl, and aralkyl; wherein k is an integer from 3 to 5, preferably wherein R3 is selected from the group consisting of alkyl, preferably C1-C12 lower alkyl; alkoxy, preferably C1-C12 lower alkoxy; acetoxy; cyanoalkyl; halogenated alkyl; cyclo
• the secondary amino functional organosilicones are bis[sec­ondary ⁇ -amino-functionalized] organosilicones which correspond to the formula where R may be a substituted or unsubstituted alkyl, cyclo­alkyl, aryl, or aralkyl group which does not carry a primary amino group, and where each R1 may be individually selected from cyano, alkyl halogenated alkyl, preferably C1-C12 lower alkyl, alkoxy, preferably C1-C12 lower alkoxy, acetoxy, cycloalkyl, aryl, or aralkyl groups, and wherein m is an integer from 1 to about 10,000, preferably 1 to about 500.
• the R1 substituents may be the same as each other, or may be different.
• the phrase "may be individu­ ally selected," or similar language as used herein, indicates that individual R1s may be the same or different from other R1 groups attached to the same silicon atom, or from other R1 groups in the total molecule.
• the carbon chain of the ⁇ -aminoalkylene-functional organosilicone may be substituted by inert groups such as alkyl, cycloalkyl, aryl, arylalkyl, and alkoxy groups. References to secondary amino­propyl, aminobutyl, and aminopentyl groups include such substituted ⁇ -aminoalkyl groups.
• tris- or higher analogues may also be prepared by the subject process if branched or multi-functional siloxanes are utilized.
• Such higher func­tionality secondary amino-functionalized siloxanes may be useful as curing agents with resins of lesser functionality.
• Monofunctional N-substituted, secondary 4-­aminobutyl-, 5-aminopentyl, and 3-aminopropylsiloxanes may also be prepared.
• Such monofunctional siloxanes have uses as reactive modifiers in many polymer systems.
• the secondary-amine-functional organosilicone modifiers of the subject invention may be prepared through the reaction of an N-allyl secondary amine with an Si-H functional organosilicone.
• organosilicone reactants in general, are intended to include silanes and di- and polysiloxanes which have Si-H function­ality. The preferred reaction may be illustrated as follows:
• Si-H func­tional organosilicone a variety of products may be obtained.
• a polysiloxane having one or more pendant sec­ondary amino functionalities may be prepared readily from an Si-H functional cyclic siloxane:
• allylamines and corresponding ⁇ -­butenyl and ⁇ -pentenylamines are useful in this synthesis.
• amines such as the secondary alkylamines, for example dimethylamine and dipropylamine, as well as (primary) allylamine itself, fail to react in a satisfactory and reproducible manner.
• U.S. Patent 3,665,027 discloses the reaction of allylamine with a monofunc­tional hydrogen alkoxysilane. Despite the presence of the activating alkoxy groups and exceptionally long reaction times, the reaction provided at most an 85 percent yield. Further­more, the reaction produces considerable quantities of poten­tially dangerous peroxysilanes as by-products.
• the preparation disclosed is not a desirable one for producing even monofunctional ⁇ -aminopropyl trialkoxy silox­anes.
• Attempts to utilize the reaction for the preparation of higher functionality siloxanes, particularly alkyl-substituted siloxanes such as the poly(dimethyl)silicones, have not proven successful. It is also known that use of vinylamine leads only to intractable products of unspecified composition.
• amines which are suitable include N-alkyl-N-allyl amines such as N-­methyl, N-ethyl, N-propyl, N-isopropyl, N-butyl, N-isobutyl, N-­tert-butyl, and N-(2-ethylhexyl)allylamines and the like; cycloaliphatic-N-allylamines such as N-cyclohexyl, N-(2-­methylcyclohexyl), and N-(4-methylcyclohexyl)-N-allylamines; aliphatic cycloaliphatic-N-allylamines such as N-cyclohexyl­methyl and N-(4-methylcyclohexylmethyl)-N-allylamines; aralkyl-N-allyl amines such as N-cyclohexyl­methyl and N-(4-methylcyclohexylmethyl)-N-allylamines;
• N-allyl secondary amines While these and many other N-allyl secondary amines are useful for the practice of the subject invention, it must be recognized that some are more preferred than others.
• the cycloaliphatic and aryl-N-allylamines are pre­ferred. Particularly preferred are N-cyclohexyl-N-allylamine and N-phenyl-N-allylamine.
• the secondary N-allyl amines are more preferred than their ⁇ -butenyl and ⁇ -pentenyl analogues.
• Si-H functional organosilicone may be used compounds of the formula: wherein R2 is selected from the group consisting of hydrogen; alkyl, preferably C1-C12 lower alkyl; alkoxy, preferably C1-C12 lower alkoxy; acetoxy; cyanoalkyl; halogenated alkyl, preferivelyably perhalogenated alkyl; and substituted or unsubstituted cycloalkyl, aryl, or aralkyl; and wherein m and n are natural numbers from 1 to about 10,000, preferably from 1 to about 500 and more preferably from 1 to about 100; wherein p is a natural number from 3 to about 20, preferably from 4 to about 8; and wherein the sum n+m is less than about 10,000, preferably less than about 500, more preferably less than about 100; and wherein at least one R2 is hydrogen.
• R2 is selected from the group consisting of hydrogen; alkyl, preferably C1-C12 lower alkyl; alkoxy,
• the Si-H functional organosilicone is an Si-H functional disiloxane, preferably where R2 is cyanoalkyl, halogenated alkyl, alkyl, alkoxy, cycloalkyl, or aryl.
• Si-H functional organo­silicones are trimethoxy- and triethoxysilane, tetramethyldi­siloxane, tetraethyldisiloxane, 1,1,3,3,5,5-hexamethyltri­siloxane, methyltris(dimethylsiloxysilane), 1,1,3,3,5,5,7,7-­octamethyltetrasiloxane, tetramethoxydisiloxane, tetraethoxy­disiloxane, 1,1-bis(trifluoropropyl)-3,3-dimethyldisiloxane, pentamethylcyclopentasiloxane, heptamethylcyclotetrasiloxane, tetramethylcyclotetrasiloxane, methylhydrosiloxane-dimethyl­siloxane copolymers, tetraphenyldisiloxane,
• tetramethyldisiloxane Particularly preferred because of its low cost and ready availability is tetramethyldisiloxane.
• Mixed-­substituted alkyl-aryl siloxanes such as 1,3-dimethyl-1,3-di­phenyldisiloxane are also useful.
• N-allyl secondary amine and Si-H functional organosilicone are preferably reacted neat, in the absence of solvent.
• solvents which are inert under the reaction conditions may be utilized if desired.
• the use of solvent may affect both the average molecular weight of the product polysiloxane and the molecular weight distribution.
• the reaction temperature is preferably maintained between about 20°C and 150°C depending upon the nature and amount of catalyst and reactants.
• a catalyst is generally necessary to promote reaction between the amine and the Si-H functional organosilicone. Surprisingly, it has been found that even rather inefficient catalysts such as hexafluoro­platinic acid and hexachloroplatinic acid are highly effective, frequently resulting in quantitative yields.
• Other catalysts which are useful include those well known in the art, typically platinum catalysts in which the platinum is present in ele­mental or combined states, particularly di- or tetravalent compounds.
• Useful catalysts are, for example, platinum supported on inert carriers such as aluminum or silica gel; platinum compounds such as Na2PtCl4, and the pre­viously mentioned platinic acids, particularly hexachloro- and hexafluoroplatinic acids.
• alkylplatinum halides siloxyorganosulfur-platinum or aluminoxyorganosulfur­platinum compositions, and those catalysts prepared through the reaction of an olefinic-functional siloxane with a platinum compound as disclosed in U.S. Patents 3,419,593; 3,715,334; 3,814,730; and 4,288,345.
• Other catalysts may also be effec­tive, such as those found in U.S.
• Patent 3,775,452 All the foregoing U.S. Patents are herein incorporated by reference. However, because of its (relatively) low cost and the high yields it produces, hexachloroplatinic acid is the catalyst of choice.
• Purification of the secondary amine-functionalized organosilicone product is accomplished by methods well known to those skilled in the art of purifying silicones. Generally, vacuum distillation is utilized, for example distillation at pressures less than about 1 torr. In some cases, purification may be effectuated by stripping off light fractions under vacuum, optionally with the aid of an inert stripping agent such as nitrogen or argon.
• the secondary amine-functionalized organosilicones may be utilized as such, or they may be further polymerized with additional silicon-containing monomers to produce higher molecular weight secondary amine-functionalized polysilox­anes.
• a secondary amine-functionalized tetra­methyl disiloxane may be converted easily to a secondary amine­terminated poly(dimethylsiloxane) by equilibration with octamethylcyclotetrasiloxane:
• the equilibration co-polymerization is facilitated through the use of catalysts well known to those skilled in the art.
• a particularly useful catalyst which is relatively inexpensive and readily available is tetramethylammonium hydroxide.
• many other catalysts are also suitable, such as potassium hydroxide, cesium hydroxide, tetramethylammonium siloxanolate, and tetrabutylphosphonium hydroxide, which are also preferred.
• a different siloxane comonomer may be added to the reaction mixture.
• a secondary amine-terminated tetra­methyldisiloxane may be reacted on a mole to mole basis with octaphenylcyclotetrasiloxane to produce a copolymer poly­siloxane having the nominal formula:
• the secondary amine-terminated di­siloxane or polysiloxane may be reacted with mixtures of siloxane monomers to form block and block heteric structures.
• N-allylaniline (0.200 mole) and 1,1,3,3-tetramethyl­disiloxane (0.100 mole) are introduced along with 0.05 g hexachloroplatinic acid into a 100 ml cylindrical glass reactor equipped with reflux condenser, nitrogen inlet, and stir bar.
• the contents of the reaction are heated and maintained while stirring, at approximately 70°C, for a period of ten hours.
• the IR spectrum of the resulting viscous oil shows no peaks corresponding to Si-H, indicating completion of the reaction.
• the crude product is mixed with carbon black and stirred overnight at room temperature. The product is filtered through silica gel and the filter cake washed with toluene.
• Volatile fractions are removed by stripping under vacuum at 150°C to give a slightly colored oil.
• the oil is further purified by vacuum distillation at ⁇ 1 torr at 223-230°C.
• the yield of 1,3-­bis(N-phenyl-3-aminopropyl)-1,1,3,3-tetramethyldisiloxane is virtually quantitative.
• N-­allylcyclohexylamine (0.173 mole), 1,1,3,3,-tetramethyldi­siloxane (0.0783 mole), and 0.05 g hexachloroplatinic acid are stirred at 70°C for eight hours at 110°C under nitrogen.
• the product in nearly quantitative yield, is purified by vacuum distillation at ⁇ 1 torr at a temperature of 207-210°C.
• 1,3-Bis(N-phenyl-3-aminopropyl)-1,1,3,3-tetramethyl­disiloxane (30.0 g), octamethylcyclotetrasiloxane (12.0 g), and tetramethylammonium hydroxide (0.06 g) are charged to a 500 ml glass reactor equipped with a reflux condenser, nitrogen inlet, and mechanical stirrer. The contents of the reactor are stirred at 80°C for 30 hours, then at 150°C for four hours under N2 blanket. After filtration, the filtrate was further purified by eliminating volatile fractions under vacuum at 180°C. The resulting oligomer was a colorless viscous oil.
• 1,3-Bis(N-phenyl-3-aminopropyl)-1,1,3,3,-tetramethyl­disiloxane (4.0 g) is treated with octamethylcyclotetrasiloxane (100 g) and tetramethylammonium hydroxide (0.06 g) in a manner similar to that described in Experiment 5.
• the resulting oligomer is a colorless viscous oil having an average molecular weight of about 10,000.
• 1,3-Bis(N-cyclohexyl-3-aminopropyl)-1,1,3,3-tetra­methyldisiloxane (4.0 g) is treated with octamethylcyclotetra­siloxane (100 g) and tetrabutylphosphonium hydroxide (0.06 g) at 110°C for four hours and 150°C for three hours under nitrogen. Filtration followed by elimination of volatile fractions under vacuum at 160°C gives a secondary amine terminated silicone oligomer having an average molecular weight of about 10,000.
• thermosetting resin systems with which the subject invention modifiers are useful include but are not limited to epoxy resins, cyanate resins, maleimide-group-­containing resins, isocyanate resins, unsaturated polyester resins, and the like. Particularly preferred are those resins which are reactive with secondary amines. Most preferred are the epoxy, cyanate, and maleimide resins.
• Epoxy resins are well known to those skilled in the art. Such resins are characterized by having an oxiranyl group as the reactive species.
• the most common epoxy resins are the oligomeric resins prepared by reacting a bisphenol with epichlorohydrin followed by dehydrohalogenation.
• Preferred bisphenols are bisphenol S, bisphenol F, and bisphenol A, particularly the latter.
• Such resins are available in wide variety from numerous sources.
• Aliphatic epoxy resins are also useful, particularly those derived from dicyclopentadiene and other polycyclic, multiply unsaturated systems through epoxida­tion by peroxides or peracids.
• epoxy resins containing dehydrohalogenated epichlorohydrin derivatives of aromatic amines are generally used.
• the most preferred of these resins are the derivatives of 4,4′-­methylenedianiline and p-aminophenol. Examples of other epoxy resins which are useful may be found in the treatise Handbook of Epoxy Resins by Lee and Neville, McGraw-Hill, New York, c. 1967.
• Suitable curing agents include primary and secondary amines, carboxylic acids, and acid anhydrides. Examples of suitable curing agents may be found in Lee and Neville, supra , in chapters 7-12. Such curing agents are well known to those skilled in the art.
• a particu­larly preferred curing agent for elevated temperature use is 4,4′-diaminodiphenylsulfone.
• the maleimide-group containing resins useful for the practice of the subject invention are generally prepared by the reaction of maleic anhydride or a substituted maleic anhydride such as methylmaleic anhydride with an amino-group-containing compound, particularly a di- or polyamine. Such amines may be aliphatic or aromatic.
• Preferred maleimides are the bis­maleimides of aromatic diamines such as those derived from the phenylenediamines, the toluenediamines, and the mehtylenedi­anilines.
• a preferred polymaleimide is the maleimide of polymethylenepolyphenylenepolyamine (polymeric MDA).
• aliphatic maleimides derived from aliphatic di- and polyamines are useful. Examples are the maleimides of 1,6-hexanediamine, 1,8-octanediamine, 1,10-decanediamine, and 1,12-dodecanedi­amine. Particularly preferred are low melting mixtures of aliphatic and aromatic bismaleimides. These and other maleimides are well known to those skilled in the art. Additional examples may be found in U.S. Patents 3,018,290; 3,018,292; 3,627,780; 3,770,691; 3,770,705; 3,839,358; 3,966,864; and 4,413,107.
• polyaminobis­maleimides which are the reaction product of an excess of bismaleimide with a diamine as disclosed in U.S. Patent 3,562,223 may be useful.
• bismaleimide composi­tions containing alkenylphenolic compounds such as allyl and propenyl phenols as disclosed in U.S. Patents 4,298,720 and 4,371,719.
• such comonomers may be useful in resin compositions containing epoxy and cyanate resins.
• Cyanate resins may also be used to advantage in the subject invention. Such resins containing cyanate ester groups are well known to those skilled in the art.
• the cyanates are generally prepared from a di- or polyhydric alcohol by reaction with cyanogen bromide or cyanogen chloride. Cyanate resin preparation is described in U.S. Patent 3,740,348, for example.
• Preferred cyanates are the cyanates derived from phenolic hydrocarbons, particularly hydroquinone, the various bisphenols, and the phenolic novolak resins such as those disclosed in U.S. Patents 3,448,071 and 3,553,244.
• a prereact is prepared by heating to 145°C, for two hours under nitrogen, a mixture containing 15.0 g of the secondary amine-functionalized silicone oligomer of Example 4 and 13.8 g of DER® 332, an epoxy resin which is a diglycidyl ether of bisphenol A available from the Dow Chemical Company, Midland, MI, which has an epoxy equivalent weight of from 172 to 176.
• the resulting product is a homogenous, viscous oil.
• Example 8 To 2.88 g of the prereact of Example 8 is added 2.0 g Tactix® 742, a glycidyl ether of tris(4-hydroxyphenyl)methane, and 2.62 g DER® 332, both products of the Dow Chemical Company. The mixture was stirred at 100°C for 30 minutes. Upon cooling to 70°C, 2.0 g of 4,4′-diaminodiphenylsulfone and 0.5 g of a fumed silica (CAB-0-SIL® M-5, available from Cabot Corporation) are introduced with stirring. A catalyst solution is prepared separately by mixing 0.8 g 2-methylimidazole with 10.0 g DER® 332 at room temperature. Following addition of 0.35 g of the catalyst solution to the resin, the mixture was coated onto a 112 glass fabric.
• Tactix® 742 a glycidyl ether of tris(4-hydroxyphenyl)methane
• 2.62 g DER® 332 both products of the Dow Chemical
• a comparison resin similar to the resin of Example 9 was prepared by coating 112 glass fabric with a similarly prepared mixture containing 2.0 g Tactix® 742, 4.0 g DER® 332, 2.0 g 4,4′-diaminodiphenylsulfone, 0.5 g CAB-0-SIL M-5, and 0.35 g of the catalyst solution as prepared in Example 9.
• Example 9 The adhesive films of Examples 9 and 10 were cured by heating at 177° for four hours, 200°C for two hours, and 250° for one hour. Single lap shear strengths were measured by the method of ASTM D-1002. The comparative test results are presented in Table I below. TABLE I Al/Al Lap Shear Strengths of Cured Adhesive Compositions Test Conditions Lap Shear Strength lb/in2 Example 9 (with modifier) Example 10 (comparative - no modifier) Ambient, initial 2840 2130 177°C, initial 3290 2660 Ambient, aged1 2370 1810 177°C, aged1 3010 2560 1Aging at 177°C for 500 hours
• the secondary amine-functionalized silicone oligomers from Examples 6 and 7 respectively were treated with 0.1 g Tactix® 742 and 0.3 g DER® 332 at 130°C for one hour. Following addition of 0.15 g 4,4′-diaminiodiphenylsulfone, the resulting resin systems were cured at 177°C for two hours and 200°C for three hours. The cured elastomers demonstrated improved strength as compared to cured silicone homopolymers. Thermal stabilities of the cured elastomers were examined by thermogravimetric analysis (TGA). The results are illustrated in Table II. TABLE II TGA (°C) in Air 5% wt. loss 10% wt. loss Example 11 380 405 Example 12 350 380
• Example 13 The prereact of Example 13 (28.5 g) is mixed with Tactix® 742 (12.8 g), DER® 332 (4.3 g), and Compimid® 353 (maleimid resin of Boots-Technochemie, 16.0 g) at 130°C for 30 minutes. At 70°C, 3,3′-diaminodiphenylsulfone (13.8 g), 4,4′-­bis(p-aminophenoxy)-diphenylsulfone (6.1 g), and CAB-O-SIL M-5 (1.8 g) are introduced. The final resin mixture is coated on a 112 glass fabric. The adhesive film is cured by being heated for four hours at 177°C, two hours at 220°C, and one hour at 250°C. The single lap shear strengths (A1/A1) are 2200-psi at 20°C and 2500 psi. at 205°C, respectively.
• Tactix® 742 (12.8 g)
• DER® 332 4.3
• a mixture of the secondary amine-functionalized silicone oligomer (15.0 g) from Example 3, Compimide 353 (10.0 g), and benzoic acid (0.1 g) is heated to 140°C for six hours under N2 with vigorous stirring.
• additional Compimide (10.0 g) and tetra(o-methyl)bis­phenol F dicyanate (70.0 g) are added.
• the mixture is stirred at 120°C for 30 minutes under vacuum.
• CAB-0-SIL N70-TS, 2.6 g0
• dibutyltindilaurate (0.15 g) are intro­duced.
• the final resin mixture is coated on a 112 glass fabric.
• a resin formulation is made in a similar manner to Example 15 from a 2-piperazinyl ethyl amide terminated buta­diene-acrylonitrile copolymer (Hycar® ATBN 1300 x 16, B.F. Goodrich Co.,) (15.0 g), Compimide 353 (20.0 g), tetra(o-­methyl)bisphenol F dicyanate (70.0 g) CAB-0-SIL N70-TS (2.6 g) and the dibutyltindilaurate catalyst (0.15 g).
• pretreatment is carried out by adding the ATBN modifier to Compimide 353 at 120°C under N2 while stirring.
• the adhesive films of Examples 15 and 16 are cured by being heating for four hours at 177°C, four hours at 200°C, and two hours at 230°C.
• the single lap shear strengths (A1/A1) of these formulations are shown in Table III. TABLE III Al/Al Lap Shear Strengths of Cured Adhesive Compositions Test Conditions Shear Strength, lb,/in2 Example 15 (silicone modified) Example 16 (ATBN modified) 20°C 3280 2670 205°C 3800 2900
• the foregoing examples illustrate the versatility of secondary amine-functionalized organosilicones as modifiers for a variety of resin systems.
• the stoichiometry of the systems may be readily adjusted to enable those skilled in the art to produce elastomer modified high strength matrix resins, high-­temperature, high-strength elastomers, and high performance structural adhesives.
• the weight ratio of the heat-­curable resin system and the silicone modifier is between 99:1 and 20:80 in particular between 97:3 and 50:50.
• the term "resin system” is utilized in its con­ventional meaning, i.e. a system characterized by the presence of a substantial amount of a heat curable resin together with customary catalysts and curing agents but devoid of the secondary amine-functionalized silicone modifiers of the subject invention.
• modified resin systems of the subject invention may be used as high performance structural adhesives, matrix resins, and elastomers. These compositions are prepared by techniques well known to those skilled in the art of structural materials.
• the adhesives may be prepared as thin films from the melt, or by casting from solution. Often, the films do not have enough structural integrity to be handled easily. In this case, the adhesive is generally first applied to a lightweight support, or scrim.
• This scrim may be made of a wide variety of organic and inorganic materials, both woven and non-woven, and may be present in an amount of from about 1 to about 25 percent by weight relative to the weight of the total adhesive composition.
• the scrim adds little or no strength to the cured adhesive film, but serves to preserve the integrity of the film in its uncured state.
• Common scrim compositions include fiberglass, carbon/graphite, polyester, and the various nylons.
• the compositions of the subject invention are applied to fiber reinforcement.
• the resin/reinforcement ratio can vary widely, but most prepregs prepared using the subject compositions will contain from 10 to 60 percent by weight, preferably from 20 to 40 percent by weight, and most preferably from about 27 to 35 percent by weight of matrix resin, the balance being reinforcing fibers.
• the reinforcing fibers may be woven or non-woven, collimated, or in the form of two or three dimensional fabric, or may, in the case of casting resins, be chopped.
• the reinforcing fibers in prepregs contribute substantially to the strength of the cured prepreg or composite made from them.
• Common reinforcing fibers utilized are carbon/graphite, fiberglass, boron, and silicon; and high strength thermoplas­tics such as the aramids, high modulus polyolefins; polycarbo­nates; polyphenylene oxides; polyphenylene sulfides; polysul­fones; polyether ketones (PEK), polyether ether ketones (PEEK), polyether ketone ketone (PEKK) and variations of these; polyether sulfones; polyether ketone sulfones; polyimides; and polyether imides.
• Particularly preferred are those thermoplas­tics having glass transition temperatures (Tg) above 100°C, preferably above 150°C, and most preferably about 200°C or higher.
• the modified resins of the subject invention may or may not contain fibrous reinforcement of any of the kinds previously dis­cussed.
• the elastomers In contrast to their matrix resin kindred, the elastomers generally contain much higher proportions by weight of secondary amine-functionalized silicones or prereacts formed from them.

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• 1987
  • 1987-09-24 US US07/100,514 patent/US4847154A/en not_active Expired - Lifetime
• 1988
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