Showing papers on "Epoxy published in 1971"

Fracture energy of an epoxy composite system

Abstract: Fracture energy data are presented for an epoxy-alumina trihydrate composite system in which both the volume fraction and particle size of the dispersion were changed. These data show that the fracture energy of a brittle epoxy composite can be significantly increased by choosing the proper volume fraction and particle size of the dispersed second phase. The results are discussed in terms of several mechanisms which could account for the observed increase in fracture energy. A recently proposed mechanism of crack interaction with a second phase dispersion is qualitatively consistent with these results.

Stress Distribution in Bonded Joints

Abstract: Stress distribution in plates and tubes bonded by stepped joints, assuming generalized plane stress

The mechanical properties of an epoxy resin with a second phase dispersion

Abstract: The mechanical strength of an anhydride-cured epoxy resin was studied by means of tensile tests as a function of particle size and volume fraction of an alumina trihydrate particulate-dispersed phase. These results and those of the microscopic examination imply that the poor strength of the system may be attributed to the intrinsically low strength of the dispersion. The tensile strength can be maximised by correct formulation on the basis of either particle size or volume fraction of the dispersed second phase. The modulus increases with increasing volume fraction, but is unaffected by particle-size variation at a constant volume fraction. The addition of a silane coupling agent increases the modulus of the composite, while having a negligible or adverse effect on the other properties.

Structural material and method

Abstract: A composition comprising an intimate bonded mixture of (a) a major portion of a particulate reinforcement filler formed of the pyrolysis or incineration residue of industrial or municipal solid waste products and (b) a minor portion of a resinous thermosetting (e.g. polyester or epoxy) or thermoplastic (e.g. nylon) adhesive polymer. Also, a process in which the binder in a flowable castable polymerizable state is mixed with the above filler and molded into a desired shape prior to solidification.

Metal salt complexes of imidazolium salts as curing agents for one part epoxy resins

Abstract: EPOXY RESINS ARE BLENDED WITH METAL SALT COMPLEXES OF IMIDAZOLES TO FORM COMPOSITIONS WHICH REMAIN IN THE UNCURED STATE FOR LONG PERIODS OF TIME AT ROOM TEMPERATURE AND CURE CONVENIENTLY AT ELEVATED TEMPERATURES. THESE EPOXY RESIN COMPOSITIONS MAY BE USED AS COATINGS, ADHESIVES, POTTING COMPOUNDS, CASTINGS AND LAMINATES.

Process for preparing reinforced laminates in situ with epoxy-polyhydric phenol condensates

Abstract: LAMINATES, PARTICULARLY GLASS REINFORCED ELECTRICAL LAMINATES, ARE PREPARED IN SITU BY IMPREGNATING A GLASS CLOTH WITH A VARNISH COMPRISING (1) AN EPOXY RESIN CONTAINING AN ORGANIC PHOSPHINE OR A PHOSPHONIUM HALIDE, (2) A PHENOL, (3) A SOLVENT, (4) AN EPOXY CURING AGENT, AND OPTIONALLY (5) AN ACCELERATOR.

Reinforced concrete construction

Abstract: A reinforced concrete construction formed of a plurality of alternate, integrally bonded layers of epoxy resin-containing concrete and fiber-reinforced epoxy resin. The epoxy resin-containing concrete is a hardened mixture of hydraulic cement, aggregate, water in an amount sufficient to harden the cement, and a minor proportion of epoxy resin. Optionally, short pieces of epoxy resin coated glass fiber can be dispersed within the epoxy resin-containing concrete. The construction can be formed into a relatively thin-walled, laminated article of any desired size and configuration. Also disclosed is a method for fabricating the constructions of this invention.

Electrodeposition of epoxy compositions

Abstract: Synthetic resins which are water-dispersible epoxy resins having epoxy groups, chemically-bound quaternary ammonium base salts, can be dissolved or dispersed in water to provide aqueous coating compositions. Such compositions, in which these resins are the major resinous component, can be applied by electrodeposition and deposit on the cathode to provide coatings of improved properties, including a high degree of resistance to corrosion or staining.

Epoxy imidazole adducts as curing agents for epoxy resins

Abstract: THE ADDUCTS OF MONO- AND POLYEPOXIDES WITH IMIDAZOLES HAVING A SECONDARY AMINO GROUP IN THE RING ARE EXCELLENT LATENT CURING AGENTS FOR EPOXY RESINS AND ACCELERATORS FOR ANHYDRIDE CURING OF POLYEPOXIDES.

Imido-substituted polyester compositions

Abstract: POLYESTERS HAVING AT LEAST ONE CHEMICALLY COMBINED ALIPHATICALLY UNSATURATED IMIDO RADICAL, SUCH AS A MALEIMIDO RADICAL ARE PROVIDED AND A METHOD FOR MAKING SUCH MATERIALS. REACTION CAN BE EFFECTED BETWEEN A POLYESTER AND AN IMIDO-SUBSTITUTED ACYLHALIDE, SUCH AS A MALEIMIDOBENZOYLCHLORIDE IN THE PRESENCE OF AN ACID ACCEPTOR. BLENDS OF THE IMIDO-SUBSTITUTED POLYESTER AND A VARIETY OF ALIPHATICALLY UNSATURATED ORGANIC MONOMERS, SUCH AS STYRENE, CHLORO STYRENE, DIALLYLPHTHALATE, N-PHENYLMALEIMIDE, BIS MALEIMIDES OR ORGANIC POLYMERS SUCH AS POLYSTYRENES, STYRENE-BUTADIENE BLOCK COPOLYMERS, POLYVINYLFLUORIDE, POLYVINYLCHLORIDE, POLYESTERS, POLYSULFONE, POLYSULFONE ETHERS, POLYCARBONATE, POLYPHENYLENE OXIDES, EPOXY RESINS, PHENOL-FORMALDEHYDE RESINS, ACRYLONITRILE BUTADIENE STYRENE TERPOLYMERS, ETC., ALSO ARE PROVIDED. THE IMIDO-SUBSTITUTED POLYESTER COMPOSITIONS OF THE PRESENT INVENTION CAN BE EMPLOYED AS COATINGS, VARNISHES, INJECTION MOLDING COMPOUNDS, LAMINATING COMPOUNDS, ETC.

Effect of joint geometry on the toughness of epoxy adhesives

Abstract: Increasing joint thickness was shown to increase the toughness of epoxy joints hardened with either tetraethylenepentamine (TEPA) or hexahydrophthalic anhydride (HHPA) The increased toughness was associated with a marked increase in macroroughness An upper limit of joint thickness and hence toughness occurred because very thick joints could not be produced Residual stresses developed during cooling from the curing temperature caused the latter to separate at the interface Stress corrosion cracking resistance was also found to depend on bond thickness For the TEPA-hardened system, bond thickness had only a minor influence for thicknesses up to 25 mils; and for the HHPA-hardened system, this persisted to bond thickness of 50 mils Further increases in bond thickness for both systems caused an abrupt rise in resistance to stress corrosion cracking

Water-dispersible cationic polyurethane resins

Abstract: WATER-DISPERSIBLE CATIONIC RESINS, AND ESPECIALLY POLYURETHANE RESINS, ARE PROVIDED BY REACTING A RESIONOUS POLYEPOXIDE WITH A STOICHIOMETRIC DEFICIENCY OF PPOLYISOCYANATE TO PROVIDE AN HYDROXY-FUNCTIONAL POLYURETHANE IN WHICH TERTIRY AMINE FUNCTIONALITY IS GENERATED BY REACTION WITH A MONOSECONDARY AMINE TO PROVIDE DISPERSIBILITY IN WATER WITH THE AID OF AN ACID. SOME OF THE EPOXY FUNCTIONALITY IS CONSUMED BY ESTERIFICATION WITH A MONOCARBOXYLIC ACID TO PROVIDE INTERNAL PLASTICIZATION AND ENHANCE FILM FORMATION. THIS IS ESPECIALLY IMPORTANT WHEN THE RESINS ARE ELECTRODEPOSITED AT THE CATHODE. THE MONOCARBOXYLIC ACID MAY BE UNSATURATED TO PROVIDE A BASIS FOR CURE WHICH IS INDEPENDENT OF THE HYDROXY FUNCTIONALITY.

Epoxide blend radiation sensitive catalyst precursor

Abstract: A BLEND OF EPOXIDE MATERIAL IS PROVIDED WHICH, ALTHOUGH ESSENTIALLY FREE TO VOLATILE SOLVENTS, IS LIQUID AND TRACTABLE FOR COATING AND RELATED APPLICATIONS AT OR NEAR ROOM TEMPERATURE. THE EPOXIDE MATERIALS INCLUDE AN EPOXY PREPOLYMER OF THE TYPE OF GLYCIDYL-BISPHENOL A RESINS, EPOXIDIZED NOVOLAKS, POLYGLYCIDYL ETHERS AND ALICYCCLIC DIEPOXIDES, BLENDED WITH A BIS(EPOXYCYCLOALKYL) ESTER AND IN MANY CASES ALSO WITH A LOW VISCOSITY MONOEPOXIDE IN LIMITED PROPORTIONS. THE COMPOSITIONS PREFERABLY INCLUDE ADDITIONALLY A CATIONIC POLYMERIZATION INITIATOR, PREFERABLY A RADIATION-SENSITIVE CATALYST PRECURSOR, AND EPOXIDE POLYMERS ARE PRODUCED BY COATING SUCH COMPOSIONS ON A SUBSTRATE, FOLLOWED BY APPLICATION OF ENERGY THROUGH HEAING OR PREFERABLY THROUGH IRRADIATION, TO EFFECT SUBSTANTIAL POLYMERIZATION OF THE EPOXIDIC MATERALS OF THE COATING.

Heat curing adhesive

Abstract: An adhesive material having a long storage life is prepared by applying to a carrier, a coating composition comprising a blend of a solid epoxy resin, solid curing agent for the expoxy resin, a film-forming binder, and a dispersing medium and drying the coating to a tack-free film. The adhesive-coated carrier or the film without the carrier may be used to bond substrates by pressing the substrates together with the adhesive film between them at elevated temperatures.

Compositions for powder coatings containing acrylate polymers or esters of fluorinated fatty acids as flow control agents

Abstract: POWDER COATING COMPOSITIONS ARE DISCLOSED. IN GENERAL, INDIVIDUAL POWDER COATING COMPOSITIONS ARE A MIXTURE OF THE FOLLOWING MATERIALS. A COPOLYMER OF GLYCIDYL METHACRYLATE AND AN ETHYLENICALLY UNSATURATED COMPOUND IS FORMED IN SUCH PROPORTIONS AS TO OBTAIN A COPOLYMER WITH A GLASS TRANSITION TEMPERATURE IN THE RANGE OF 40* C. TO 90*C. AND A MOLECULAR WEIGHT ($N) IN THE RANGE OF 2500 TO 8500. THE GLYCIDYL METHACRYLATE IS PRESENT IN THE COPOLYMER FROM AT LEAST ABOUT 8% BY WEIGHT TO NO MORE THAN ABOUT 30% BY WEIGHT. ANOTHER MATERIAL OF THE COATING COMPOSITION IS A CROSS LINKING AGENT CONTAINING 90 TO 98% BY EQUIVALENT WEIGHT OF A SATURATED, STRAIGHT CHAIN, ALIPHATIC, DICARBOXYLIC ACID CONTAINING 4 TO 20 CARBON ATOMS PER MOLECULE AND 10 TO 2% BY EQUIVALENT WEIGHT OF A SATURATED, STRAIGHT CHAIN, ALIPHATIC, MONOCARBOXYLIC ACID CONTAINING 10-22 CARBON ATOMS PER MOLECULE, THE CROSS LINKING AGENT BEING PRESENT IN THE AMOUNT OF 0.8 TO 1.1 CARBOXYLIC GROUPS FOR EACH EPOXY GROUP IN THE COPOLYMER. A THIRD MATERIAL UTILIZED IN FORMING THE POWDER COATING MIXTURE IS A FLOW CONTROL AGENT WHICH FORMS AT LEAST 0.05% BY WEIGHT OF THE MIXTURE. THE FLOW CONTROL AGENT IS A POLYMER HAVING A MOLECULAR WEIGHT ($N) OF AT LEAST 1000. THE FLOW CONTROL AGENT ALSO HAS, AT THE BAKING TEMPERATURE OF THE POWDER COATING COMPOSITION, A LOWER SURFACE TENSION THAN THE SURFACE TENSION OF THE COPOLYMER.

Thermal Erosion of Electrical Insulating Materials

Abstract: The erosion of synthetic insulating materials by surface discharges constitutes an important problem in the application of these materials for high-voltage outdoor applications. A method of erosion testing is described that simulates the heat flux from surface discharges by radiant energy from a thermal imaging source. This permits accurate measurement of erosion. A theory of erosion is developed that is found to agree well with experiments performed on several cycloaliphatic epoxy resin systems.

A method of glazing greenware with an ambient epoxy resin curing composition

Abstract: An ambient cure glaze composition particularly adapted for decorating and strengthening greenware comprising a flowable composition containing a reactive epoxy liquid polymer, non-volatile diluents, coloring agents and viscosity controlling agents. The flowable composition is cured and hardened by combination with a curing agent which is absent free amine groups. The composition is non-toxic and has low dermal sensitivity.

Diagonal Tension Behavior of Boron-Epoxy Shear Panels

Abstract: In previous articles [1, 2, 3, 4, 5, 6], analysis procedures and experimental results have been presented for the buckling, vibration, and bending behavior of thin laminated composite plates. All of these papers have dealt with linear, small deflection behavior. The post-buckling, large-deflection behavior of laminated plates has not been considered, and in fact, such behavior has been virtually ignored since the low interlaminar strengths of these plates was thought to preclude appreciable post buckling strength. The present paper presents an experimental study of the post shear buckling, diagonal tension behavior of rectangular laminated boron-epoxy plates clamped on each edge. The linear theory buckling load is also compared to the experimental results.

Acoustic Emission Studies of a Boron-Epoxy Composite

Abstract: Acoustic emission and stress wave emission are terms used to describe the release of stored acoustic energy from a material when it undergoes plastic deformation, phase transformation, or fracture. This energy is released in discrete pulses characteristic of the process. If a transducer is attached to a specimen of the material emission above the threshold of the transducer can be amplified and read as acoustic emission counts. The response of the count rate measuring device depends upon the amplifier gain setting, and the number and amplitude of the pulses monitored by the transducers. Using a totalizer, the count rate can be integrated to give the sum of counts. Count rate and sum of counts (2:AE) printouts produce a pattern of energy release characteristic of a given process. This note describes how acoustic emission has been correlated with the breaking of fibers during the fracture of a boron-epoxy composite. The boron-epoxy composite material containing 66 volume percent of aligned fiber

Method for stabilizing pigmented polycarbonate resins

Abstract: A method is provided for stabilizing polycarbonate resin tinted with ultramarine pigment, involving the incorporation of the ultramarine pigment into the polycarbonate resin as an arylsiloxane-pigment blend. There also is employed with the arylsiloxane-pigment blend, polycarbonate resin stabilizers such as triorganophosphite, and a cyclo aliphatic epoxy compound. The stabilized resin can be remolded without a significant increase in the Yellow Index of the resin.

Photopolymerizable epoxy systems containing cyclic amide gelation inhibitors

Abstract: POLYMERIZATION OF EPOXIDE MONOMERS AND PREPOLYMERS, AND OF OTHER MATERIALS POLYMERIZABLE THROUGH THE ACTION OF CATIONIC CATALYSTS, IS CONTROLLED BY PROVIDING, IN ASSOCIATION WITH A RADIATION-SENSITIVE CATALYST PRECURSOR, A GELATION INHIBITOR IN THE FORM OF A CYCLIC AMIDE, SUCH AS AN N-SUBSTITUTED 2-PYRIDONE, OR A 2-PYRROLIDINONE MONOMER OR POLYMER SUBSTITUTED IN THE 1-POSITION.

Compositions containing epoxy resin, chain extender, functionally terminated elastomer and curing agent

Abstract: Hard and strong epoxy resin products of high impact resistance are made from a di-epoxy compound, a smaller than equivalent proportion of chain extender which is preferably a bis-phenol, and about 5% (based on the amount of the di-epoxy compound) of a functionally terminated elastomer which is preferably a phenol terminated liquid copolymer of butadiene and acrylonitrile, together with a curing agent active at elevated temperatures.

Stress-Rupture of S-Glass Epoxy Multifilament Strands

Abstract: The stress-rupture behavior of filamentary composites is of great concern in many long-term applications. We have begun a program to collect reliable stress-rupture data on very simple composites such as various fiber strands impregnated with an epoxy matrix. We de veloped a tensile test method for fibers, designed a stress-rupture test apparatus and verified its performance, and installed 400 test apparatuses in a controlled-environment building. This paper dis cusses the data collected to date on single-end S-glass/epoxy strands at three load levels: 83.8, 74.5, and 65.2% (based on the average breaking load). Using at least 100 specimens at each load level, we found that the time-to-break values consistently varied by a factor of 1000. The data clearly indicate a shorter life at higher loads. We are collecting data at three lower load levels: 50, 40, 33%. We are attempting to characterize the distribution function of the stress- rupture life but are not yet able to draw any conclusions.

Glass-epoxy laminates for high temperature use

Abstract: A LAMINATE IS MADE COMPRISING A PLURALITY OF BONDED LAYERS OF SHEET MATERIAL IMPREGNATED WITH A CURED RESINOUS COMPOSITION, COMPRISING A CURED ADMIXTURE OF A LIQUID LOW VISCOSITY EPOXY RESIN, NADIC METHYL ANHYDRIDE AND BENZOPHENONE-TETRACARBOXYLIC DIANHYDRIDE.