Showing papers on "Epoxy published in 1969"
TL;DR: A low-viscosity embedding medium based on ERL-4206 is recommended for use in electron microscopy and has a long pot life of several days and infiltrates readily because of its low viscosity.
12,930 citations
TL;DR: In this paper, an experimental technique was developed to determine the condi tions for the onset of reinforcement unbonding in composite materials, based upon the continuous measurement of the d...
Abstract: An experimental technique was developed to determine the condi tions for the onset of reinforcement unbonding in composite materials. The technique is based upon the continuous measurement of the d...
111 citations
TL;DR: In this article, a modi-fied two-dimensional theory for fiber buckling is presented, which is in good agreement with the experimental data obtained from two epoxy matrix systems (AF-126 and BP-907).
Abstract: The compressive strength of fibrous composites is strongly de pendent upon the effectiveness of the matrix in supporting the fibers against buckling. Proper support of boron filaments by an epoxy matrix has resulted in average compressive fiber stresses of as high as 1,330,000 psi at failure. Experimental data obtained from two epoxy matrix systems (AF-126 and BP-907) is in good agreement with a modi fied two-dimensional theory for fiber buckling.
84 citations
TL;DR: A combination of dynamic mechanical and swelling properties has been used to elucidate the structure of epoxy resin systems as a function of time and temperature of cure, concentration of flexibilizer, and curing agent concentration as discussed by the authors.
Abstract: A combination of dynamic mechanical and swelling properties has been used to elucidate the structure of epoxy resin systems as a function of time and temperature of cure, concentration of flexibilizer, and curing agent concentration. The dynamic properties of the resin in the rubbery region were used to determine the molecular weights between cross-links. The poor network structure formed with epoxies is shown by the dynamic and swelling tests. The existence of heterogeneity or two phases has been found in the epoxy resin system under certain polymerization conditions. Broad damping peaks may not be due to chemical heterogeneity but may be the result of the curing reaction continuing during the tests.
83 citations
TL;DR: In this article, the fracture energy of cast epoxy resin was measured by a novel method in the presence of various agents, and the crack spontaneously rehealed under heating to above the heat distortion temperature to give a fresh joint of about the same fracture energy as the virgin material.
Abstract: The fracture energy of cast epoxy resin was measured by a novel method in the presence of various agents. The crack spontaneously rehealed under heating to above the heat distortion temperature to give a fresh joint of about the same fracture energy as the virgin material.
73 citations
TL;DR: In this article, the storage and loss moduli were measured for laminated glass fiber reinforced epoxy composite beams at frequencies up to 9400 Hz, with relatively insensitive storage moduli.
Abstract: Measurements of storage and loss moduli are reported for laminated glass fiber reinforced epoxy composite beams at frequencies up to 9400 Hz. The storage moduli were relatively insensitive and the ...
66 citations
TL;DR: In this paper, a system comprised of approximately 50% by volume glass fibers in an epoxy resin matrix was used for measuring the orientation of short fibers during flow of short fiber composites.
Abstract: A method for characterizing the orientation of short fibers during flow of short fiber composites is described. A system comprised of approximately 50% by volume glass fibers in an epoxy resin matrix was used for this study. A glass rheometer was used to observe steel tracer fibers, which were incorporated into feed particles with the glass. By reacting the epoxy resin with a secondary amine, a product was obtained which did not react further during the measurements. The product also had a viscosity at room temperature similar to com mercial systems at processing temperatures; this made flow measure ments at room temperature possible. A technique of data reduction for the orientation measurements is described.Early results show that, at these high fiber loadings, plug flow with little change in orientation occurs above and below the constriction in the rheometer tube. At the constriction, particles are sheared into strands. If feed particles containing pre-oriented fibers are not used, a "log jam" results...
49 citations
TL;DR: In this paper, a method for determining the relative amount of alcohol side reaction which occurs in reactions of epoxy compounds with active hydrogen compounds has been investigated, which involves determining the ratio of rates of the successive reaction, epoxide-active hydrogen compound and epoxide generated secondary alcohol, in the reaction of epoxide and active hydrogen compound at respectively a 2:1 mole ratio.
Abstract: A method for determining the relative amount of alcohol side reaction which occurs in reactions of epoxy compounds with active hydrogen compounds has been investigated. It involves determining the ratio of rates of the successive reaction, epoxide-active hydrogen compound and epoxide-generated secondary alcohol, in the reaction of epoxide and active hydrogen compound at respectively a 2:1 mole ratio. Rate ratios are reported for the bulk reaction of bisphenol-A and the diglycidyl ether of bisphenol-A under different reaction conditions. The data correlated with the properties of high molecular weight polymers. Amines with β-hydroxyl groups were very selective catalysts.
42 citations
TL;DR: The preparation of various epoxy resins containing acidic and basic curing agents was investigated and the addition basic and acidic curing agents in the resins was observed to influence their solubility in acidic and alkaline buffer, respectively.
40 citations
TL;DR: The importance of the rate of loading on the fracture characteristics of a unidirectional composite is shown by forming a small notch at one side of each specimen and a tensile crack then spread in the resin to the opposite side.
Abstract: A SIMPLE experiment has been carried out which shows the importance of the rate of loading on the fracture characteristics of a unidirectional composite. Three specimens of flexibilized epoxy resin, 12.7 mm × 6.4 mm in cross-section and 50 mm test length reinforced with 3 volumes per cent continuous silica fibres in unidirectional array, were loaded to fracture at 0.051 mm/min, 5.1 mm/min, 510 mm/min respectively, at room temperature. Fracture was deliberately encouraged by forming a small notch at one side of each specimen and a tensile crack then spread in the resin to the opposite side. Fibre fracture did not coincide with resin fracture but was spread over a region on either side of the resin crack.
32 citations
Patent•
24 Apr 1969TL;DR: In this paper, a curable epoxy composition comprising an epoxy resin, a polycarboxylic acid anhydride curing agent, and a polyvalent metal complex of acetylacetone is presented.
Abstract: A curable epoxy composition comprising an epoxy resin, a polycarboxylic acid anhydride curing agent, and, as a cure catalyst, a polyvalent metal complex of acetylacetone said composition, having improved storage stability, and thermoset properties, and a process for the preparation thereof.
Patent•
17 Nov 1969TL;DR: In this paper, a modified EPOXY RESIN COMPOSITION is described, which is part of an ORGANIC ISOCYANATE and has an average MOLECULAR WEIGHT of at least 500 but less than 5000.
Abstract: WHERE X AND X'' IS SH, OH, NH2 AND COOH AND R IS ALKYL, ARYL, ALIPHATIC, AROMATIC, AND BRANCHED ALIPHATIC; WHEREIN SUCH POLYMERIC MODIFIER HAS AN AVERAGE MOLECULAR WEIGHT OF AT LEAST ABOUT 500 BUT LESS THAN 5000 AND IS COMPATIBLE WITH THE EPOXY RESIN; AND WHEREIN THE MODIFIED EPOXY RESIN COMPOSITION ARE PARTICULARLY USEFUL IN ADHESIVE FORMULATIONS. X-R-X'' THIS INVENTION ID DIRECTED TO THERMOSETTABLE RESIN COMPOSITIONS COMPRISING ESSENTIALLY AN EPOXY RESIN AND BETWEEN ABOUT 5 TO 50 PARTS PER HUNDRED PARTS OF EPOXY RESIN OF A REACTIVE TERMINATED URETHANE TYPE POLYMERIC MODIFIER FOR SUCH EPOXY RESIN WHEREIN SUCH MODIFIER IS THE REACTION PRODUCT OF APPROXIMATELY TWO MOLAR EQUIVALENTS OF AN ORGANIC ISOCYANATE, APPROXIMATELY ONE MOLAR EQUIVALENT OF A POLYMERIC "BACKBONE" MATERIAL HAVING AN AVERAGE MOLECULAR WEIGHT OF FROM ABOUT 500 TO 5000, WHICH IS TERMINATED WITH AN ACTIVE HYDROGEN CAPABLE OF REACTING WITH SAID ORGANIC ISOCYANATE AND WHICH CONTAINS FLEXIBILIZING GROUPS IN THE MAIN POLYMER CHAIN, AND APPROXIMATELY ONE MOLAR EQUILVALENT OF A "CAPPANT" MATERIAL OF THE GENERAL FORMULA
TL;DR: In this paper, internal friction and creep measurements have been used to reveal the mechanism of cure in epoxy resins cross-linked with diethylene triamine (DETA), and the β-relaxation is associated with the main glass transition of the undercured resin network.
Abstract: Internal friction and creep measurements have been used to reveal the mechanism of cure in epoxy resins cross-linked with diethylene triamine (DETA). The β-relaxation is associated with the main glass transition of the undercured resin network. The glass transition temperature (Tg) is about 40° C above the maximum temperature of cure and the curing reaction slows down about 2 h after each increase of the temperature. At 25° C the cure is only about half complete and since in this resin, when fully cross-linked, Tg is at about 140° C, temperatures of 100° C or over are needed to complete cure.
Patent•
21 Aug 1969
TL;DR: In this paper, the application of environmental protection for discrete electrical components mounted on a circuit substrate is precisely controlled by first forming a thermosetting material, such as a bisphenol epoxy resin, into a body having a cavity sufficient to accommodate the electrical component, preferably by mechanical compaction of the material in powder form, placing the preformed body in the inverted position over the circuit element, and then heating the assembly to cure the material to at least a semi-hardened state.
Abstract: The application of environmental protection for discrete electrical components mounted on a circuit substrate is precisely controlled by first forming a thermosetting material, such as a bisphenol epoxy resin, into a body having a cavity sufficient to accommodate the electrical component, preferably by mechanical compaction of the material in powder form, placing the preformed body in the inverted position over the circuit element, and then heating the assembly to cure the thermosetting material to at least a semi-hardened state. In one embodiment, a second thermosetting material, having a coefficient of thermal expansion closely approximating that used for the preformed body in order to minimize internal stresses during thermal cycling of the completed assembly, is used as a protective overcoating.
Patent•
22 Jul 1969
TL;DR: A FLUID, HEAT CURABLE MAGNETIC COATING COMPOSITION as discussed by the authors is a three-part partitioning EPOXY binder, in which magnetic particles are dispersed in three different parts of the binder.
Abstract: A FLUID, HEAT CURABLE MAGNETIC COATING COMPOSITION IN WHICH MAGNETIC PARTICLES ARE DISPERSED IN A THREE COMPONENT THERMOSETTING EPOXY BINDER. THE COATING ALSO CONTAINS VOLATILE SOLVENTS. THE EPOXY BINDER CONTAINS (1) A HIGH EQUIVALENT WEIGHT EPOXY WITH A MOLECULAR WEIGHT OF ABOUT 400-4,000 PER EPOXY GROUP, (2) A LOW EQUIVALENT WEIGHT EPOXY WITH AMOLECULAR WEIGHT OF ABOUT 130211 PER EPOXY GROUP. AND (3) AN AROMATIC POLYAMINE CURING AGENT HAVING AT LEAST TWO PRIMARY AMINE GROUPS PER MOLECULE.
Patent•
21 Aug 1969
TL;DR: In this article, the authors describe a COATING COMPOSITION SUITABLE for COATING or painting WET OR DAMP SUBSTRATES, which is capable of CURING to a HARD FILM under water, using an EPOXY RESIN and a SUBSTANTIALLY WATER-INSENSITIVE CURing AGENT.
Abstract: THIS INVENTION RELATES TO A COATING COMPOSITION SUITABLE FOR COATING OR PAINTING WET OR DAMP SUBSTRATES WHICH IS CAPABLE OF CURING TO A HARD FILM UNDER WATER COMPRISING AN EPOXY RESIN AND A SUBSTANTIALLY WATER-INSENSITIVE CURING AGENT FOR SAID RESIN COMPRISING A REACTION PRODUCT OF A POLYAMINE AND A MONOFUNCTIONAL EPOXIDE-CONTAINING MATERIAL.
Patent•
22 Dec 1969
TL;DR: MECHANICAL FASTENERS and Stable PRESSure-ACTivatable ADHESIVE System as discussed by the authors are based on ENCAPSULATED RESIN, Pas discussed by the authorsERABLY EPOXY and NON-VOLATILE CURATIVE.
Abstract: MECHANICAL FASTENERS AND STABLE PRESSURE-ACTIVATABLE ADHESIVE SYSTEM THEREFORE BASED ON ENCAPSULATED RESIN, PREFERABLY EPOXY AND NON-VOLATILE CURATIVE THEREFOR, PREFERABLY AN AMINE SUCH AS 1,3-BIS-4-PIPERIDYLPROPANE OR IMIDAZOLE, THE CAPSULES AND CURATIVE BEING CONTAINED IN POLAR SOLVENT-FREE BINDER WHICH CAN HOLD SYSTEM ON A BUTMENT SURFACES OF FASTENER.
Patent•
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23 Jul 1969
TL;DR: In this article, Seikan et al. presented a method for prepping metal sheets with a curable precondensate of a phenolic resol (I) and an epoxy resin (II).
Abstract: 1,254,048. Laminates. TOYO SEIKAN K.K. 12 July, 1969, No. 35220/69. Heading B5N. [Also in Divisions B1-B2, B8 and C3] Metal sheets, e.g. of steel or aluminium, which are laminated together with a polyamide adhesive are first primed with a curable precondensate of a phenolic resol (I) and an epoxy resin (II). I is prepared by condensing formaldehyde with a mixture of 50-90% by wt. of p-cresol and 50-10% by wt. of another phenol which has at least 3 positions capable of reaction with HCHO, e.g. phenol, m-cresol or bisphenol A. II is a condensate of a p,p 1 -dihydroxydiphenylalkane, e.g. bisphenol A and an epihalohydrin. The wt. ratio of I: II may be from 20: 80 to 60: 40. II may have an epoxide equivalent of 450-5500. In preferred precondensates 750% of the epoxy groups of II remain uncondensed. In an example, a steel sheet is first coated at 8-10 A with a precondensate of a bisphenol A polyglycidyl ether and a resol prepared from a mixture of m- and p-cresol. The polyamide adhesive was a polymer of 12-aminolauric acid at a thickness of 50 A. The laminate was prepared by contacting two such coated surfaces under pressure in a high frequency heater for 50 milliseconds.
TL;DR: In this paper, the temperature dependence of relative modulus observed in filled thermoset, thermoplastic, and polyelectrolyte salt matrices is explained on the basis of induced stresses produced by the differences in the thermal expansion coefficients of the constituent materials.
Abstract: The temperature dependence of relative modulus observed in filled thermoset, thermoplastic, and polyelectrolyte salt matrices is explained on the basis of induced stresses produced by the differences in the thermal expansion coefficients of the constituent materials. The analysis is based on the assumption that the modulus of the matrix in a filled polymer is less than that of the unfilled polymer. The temperature dependence of relative modulus is expressed as a function of the difference in thermal expansion coefficients, the volume fraction, the relative modulus in the unstressed state, and mechanical properties of the phases. Agreement is good between the analysis and experimental results for three systems: epoxy and glass, polyethylene and wollastonite, and a polyelectrolyte salt with mica and asbestos.
Patent•
05 May 1969
TL;DR: In this article, a method of bonding materials, particularly wood, using foamed gap-filling adhesives is disclosed, which are prepared using amine-modified aldehyde condensation polymers in which a foaming agent or agents have been incorporated.
Abstract: A method of bonding materials, particularly wood, using foamed gap-filling adhesives is disclosed. The adhesives are prepared using amine-modified aldehyde condensation polymers in which a foaming agent or agents have been incorporated. The resins cure rapidly at ambient temperature and make excellent construction adhesives.
Patent•
05 Dec 1969
TL;DR: In this paper, an ablative coating composition and a substrate coating with such composition are disclosed, which includes an epoxy resin, a curing agent, a silicone resin, fibrous reinforcing material and a salt mixture containing at least one non-alkali metal inorganic phosphate and borate.
Abstract: An ablative coating composition and a substrate coating with such composition are disclosed. The composition includes an epoxy resin, a curing agent, a silicone resin, fibrous reinforcing material and a salt mixture containing at least one non-alkali metal inorganic phosphate and borate.
Patent•
21 Apr 1969
TL;DR: An ELASTOMERIC reaction product of an EPOXY RESIN and at least one AMINE HAVING A MINIMUM OF 2 AMINO HYDROGEN ATOMS per MOLECULE, at least 1 PORTION OF SAID AMINE BEING A POLYETHER DISECONDARY AMINE as mentioned in this paper.
Abstract: AN ELASTOMERIC REACTION PRODUCT OF AN EPOXY RESIN AND AT LEAST ONE AMINE HAVING A MINIMUM OF 2 AMINO HYDROGEN ATOMS PER MOLECULE, AT LEAST ONE PORTION OF SAID AMINE BEING A POLYETHER DISECONDARY AMINE.
Patent•
06 Nov 1969
TL;DR: In this paper, a mixture of an EPOXY resin and an ORGANOIMIDAZOLIUM salt is used to create a stable, stable, and CURABLE EPIRE RESIN COMPOSITIONS.
Abstract: STORAGE-STABLE, CURABLE EPOXY RESIN COMPOSITIONS COMPRISE A MIXTURE OF AN EPOXY RESIN AND AN ORGANOIMIDAZOLIUM SALT. PREFERABLY, THE COMPOSITION INCLUDES A NITROGENOUS COMPOUND, SUCH AS UREA, DICYANDIAMIDE, MELAMINES OR THIOUREAS. THESE COMPOSITIONS ARE STORAGE-STABLE IN THE CURED STATE FOR LONG PERIODS OF TIME AT ROOM TEMPERATURE, BUT CAN BE EASILY CURED AT ELEVATED TEMPERATURES TO PROVIDE PRODUCTS HAVING EXCELLENT SHEER STRENGTH, PEEL STRENGTH AND OTHER PROPERTIES. THESE EPOXY RESIN COMPOSITIONS CAN BE USED AS COATINGS, ADHESIVES, POTTING COMPOUNDS, IN CASTINGS AND LAMINATES, AND FOR SIMILAR PURPOSES.
TL;DR: In this article, a torsion pendulum has been used to detect the first steps of pyrolysis in resin heated in air, and embrittlement due to these crosslinks starts on the surface of the resin and progresses inwards with time.
Abstract: A torsion pendulum has been found to be a sensitive tool to detect the first steps of pyrolysis. It has been shown that some primary bonds break at elevated temperatures, but in the presence of oxygen, new crosslinks can form simultaneously. In resin heated in air, embrittlement due to these crosslinks starts on the surface of the resin and progresses inwards with time.
Patent•
19 Mar 1969TL;DR: In this paper, the reaction products of APPROXIMATELY EQUIMOLECULAR PROPORTIONS of ACID ANHYDRIDE, SUCH AS PHTHALIC ANHY DRIDE, and a POLYAMINE, as well as DIETHYLENETRIAMINE are LATENE HARDENERS for EPOXY RESINS.
Abstract: THE REACTION PRODUCTS OF APPROXIMATELY EQUIMOLECULAR PROPORTIONS OF AN ACID ANHYDRIDE, SUCH AS PHTHALIC ANHYDRIDE, AND A POLYAMINE, SUCH AS DIETHYLENETRIAMINE, ARE LATENE HARDENERS FOR EPOXY RESINS HAVING MORE THAN ONE 1,2-EPOXY GROUPS PER MOLECULE AND, WHEN COMBINED WITH AN EPOXY RESIN, PROVIDE SYSTEMS WHICH ARE STABLE FOR LONG PERIODS WHEN STORES AT AMBIENT OR MODERATELY ELEVATED TEMPERATURES WHILE PROVIDING ON CURING FOR RELATIVELY SHORT PERIODS AT ELEVATED TEMPERATURES, ON THE ORDER OF 100150*C., HARDENED PRODUCTS OF GOOD PROPERTIES.
Patent•
24 Jul 1969
TL;DR: In this article, the appearance of spots or stars under the surface of a resin portion of an epoxy-glass fiber laminate, is prevented or significantly diminished by a laminating process which includes curing plies of glass cloth and epoxy resin at an elevated temperature, e.g., 300 DEG to 400 DEG F., at a high pressure, i.e., 750 to 1,500 pounds per square inch.
Abstract: Measling, the appearance of spots or stars under the surface of a resin portion of an epoxy-glass fiber laminate, is prevented or significantly diminished by a laminating process which includes curing plies of glass cloth and epoxy resin at an elevated temperature, e.g., 300 DEG to 400 DEG F., at an elevated pressure, e.g., 750 to 1,500 pounds per square inch, until gel formation occurs by reaction of the epoxy resin and curing agent, after which heating is continued at approximately the same temperature but at a lower pressure, e.g., 50 to 400 lbs./sq. in. Suitably, the initial curing step lasts for about 30 to 80 minutes and the subsequent step takes about 20 to 50 minutes, such times varying with the thickness of the laminate, the nature of the expoxy resin, the temperature employed, the geometry of the laminate, the type of reinforcing cloth, the curing apparatus used and the presence or absence of metal molded into the plastic. After completion of heating, the laminate is cooled in the press and is then removed.
Patent•
28 Nov 1969
TL;DR: The Self-Stable EPOXY RESIN COMPOSITION as discussed by the authors is a self-stabilizing epoxy resin that can be applied to a DRY POWDER for FLUIDIZED BED or DRY SPRAYCOATING of HEATED OBJECTS to provide THROUGH FLEXIBLE PROTECTIVE COATINGS.
Abstract: SHELF-STABLE EPOXY RESIN COMPOSITION THAT CAN BE PULVERIZED TO A DRY POWDER FOR FLUIDIZED BED OR DRY SPRAYCOATING OF HEATED OBJECTS TO PROVIDE THROUGH FLEXIBLE PROTECTIVE COATINGS. THE COMPOSITION COMPRISES A HIGH-MELTING DIGLYCIDYL ETHER OF A DIHYDRIC PHENOL AND AN ADDUCT ONE MOL OF TRIMELLITIC ANHYDRIDE PER HYDROXYL EQUIVALENT OF A POLYALKYLENE GLYCOL, ESPECIALLY POLYETHYLENE GLYCOL.
Patent•
26 Sep 1969TL;DR: In this article, a 1,2-EPOXY resin compositions where the EPOXY RESIN CONTAINS more than one 1 2 -EPOY GROUPS per MOLECULE, are discussed.
Abstract: THIS INVENTION RELATES TO 1,2-EPOXY RESIN COMPOSITIONS WHEREIN THE EPOXY RESIN CONTAINS MORE THAN ONE 1,2-EPOXY GROUPS PER MOLECULE, WHICH COMPOSITIONS CONTAIN NOVEL ADVANCEMENT CATALYSTS SELECTED FROM THE GROUP CONSISTING OF IMIDAZOLES, BENZIMIDAZOLES, DIHYDROPYRIMIDINES, IMIDAZOLINES, TETRAHYDROPYRIMIDINES, DIHYDROQUINAZOLINES, THEIR SALTS AND MIXTURES THEREOF; AND TO A PROCESS FOR PREPARING HIGHER 1,2-EPOXY RESINS FROM LOWER EPOXY RESINS EMPLOYING SAID ADVANCEMENT CATALYSTS. THE COMPOSITION CAN BE SUITABLY USED AS INTERMEDIATES IN THE PREPARATION OF CURED EPOXY RESINS OF HIGH MOLECULAR WEIGHT WHICH ARE USED AS COATINGS, ADHESIONS, ELECTRICAL INSULATORS AND THE LIKE.