MXPA00006955A - Curable epoxy-based compositions - Google Patents

Abstract

This invention relates to curable epoxy-based compositions for use in the field of microelectronics, such as those having an epoxy compound which has two or more epoxy groups per molecule optionally a polythiol compound which has two or more thiol groups per molecule, a latent hardener, and at least one solid organic acid which is substantially insoluble in a mixture of the foregoing components at room temperature. The solid organic acid may be selected from the group consisting of:aliphatic, cycloaliphatic and aromatic carboxylic acids and derivatives thereof, aliphatic, cycloaliphatic, and aromatic quinones and derivatives thereof, phenols and derivatives thereof and enolisable aliphatic, cycloaliphatic and aromatic compounds and derivatives thereof. The solid organic acid should havea pKa of less than or equal to about 12.0, desirably less than or equal to about 10, and often less than or equal to about 9.0, such as less than or equal to about 7.5. The invention also relates to curable epoxy-based compositions including an epoxy compound, a thixotropy-conferring component, a latent hardener and at least one of the solid organic acids above demonstrating improved rheological properties such as yield point maintenance and viscosity maintenance over time.

Description

COMPOSITION IS EPOXY-BASED CU RABLES BACKGROUND OF THE I NVENTION FIELD OF THE INVENTION This invention relates to epoxy-based curable compositions such as those having an epoxy compound which has two or more epoxy groups per molecule, a polythiol compound which has two or more thiol groups per molecule, a hardener latent, and at least one solid organic acid that is substantially n solvate in a mixture of the above components at room temperature. The solid organic acid may be selected from the group consisting of: aliphatic, cycloaliphatic, and aromatic carboxylic acids and derivatives thereof, aliphatic, cycloaliphatic and aromatic quinones and derivatives thereof, phenols and derivatives thereof and aliphatic, cycloaliphatic and enolizable aromatics and derivatives thereof. The solid organic acid must have a pKa of less than or equal to about 12.0, suitably less than or equal to 10, such as less than or equal to about 9.0, and often less than or equal to about 7.5. In another aspect of this invention, one part epoxy based curable compositions with improved rheological properties are provided, such as improved shelf life stability, particularly with respect to point-in-time maintenance, viscosity maintenance over time, and pot life at room temperature.

BRIEF DESCRIPTION OF RELATIVE TECHNOLOGY Epoxy-based curable compositions are well known. Such compositions are used as adhesives, coating agents, sealing agents, and can also be used as pouring agents.

The epoxy-based compositions are also used in the electronics industry for the manufacture of laminates with heat-resistant printed circuits for tablets with printed circuits (pcbs). One use of the curable epoxy compositions is to glue components for surface mounting to pcbs. The epoxy / polythiol containing compositions have conventionally been used as two part compositions. This was due at least in part to the instability of a one-part composition, which has an epoxy resin and a polythiol component and a liquid (soluble) tertiary amine curing agent or hardener. The compositions of such a part where the epoxy-polythiol resin and the curing agent or hardener were mixed at room temperature had working lives or "pot" in the order of minutes to a few hours. These properties impose practical restrictions on the end-use applications of such compositions. Consequently, many traditional epoxy / polythiol compositions have been formulated as two-part compositions. Commercially available latent curing agents used in one-part epoxy resin adhesive formulations usually provide such formulations with a combination of good storage stability and moderate reactivity at elevated temperatures. Examples of such commercially available latent curing agents include dicyandiamide and dibasic acid dihydrazide. These curing agents are useful in formulating epoxy resin compositions with excellent storage stability. However, to achieve curing, these curing agents ordinarily require heating at temperatures greater than 150 ° C for extended periods of time. U.S. Patent No. 5,430,112 (Sakata) discloses epoxy / polythiol resin compositions that are reported to exhibit improved stability, i.e., extended pot life, if a latent curing accelerator is used. solid dispersion-type amine adduct, or (b) the product of a reaction between a compound containing one or more isocyanate groups in its molecule and a compound having two or more primary and / or secondary amino groups in its molecule. Compounds (a) and (b) above are each reported to act as a "latent hardener", being activated at higher temperatures. In particular, the composition described in the '12 patent contains (1) an epoxy resin having two or more epoxy groups in its molecule, (2) a polythiol compound having two or more thiol groups in its molecule (3) an accelerator that is (a) a latent curing accelerator of solid dispersion-type amine adduct, or (b) the product of a reaction between a compound containing one or more isocyanate groups in its molecule and a compound having less a primary and / or secondary group in its molecule. Examples given of latent-cure accelerators of solid dispersion-type amine adduct are those sold under the trade names Ajicure PN-H or Ajicure PN-23 (commercially available from Ajinomoto Co., Inc., Tokyo, Japan). The compositions containing these latent curing accelerators of amine adduct show improved stability at room temperature over conventional formulations based on tertiary amine curing agents. However, in practice such compositions with a pot life in excess of one week at room temperature, show a poor ability to cure, that is, their ability to cure in less than 30 minutes at 80 ° C is poor. The stability of an epoxy / polythiol resin composition of the '12 Patent is reported to be improved by the use of a latent curing accelerator of solid dispersion-type amine adduct and / or the product of an isocyanate and a group that contains amine, although compositions containing Ajicure PN-23 are not described. However, the improved stability, for at least the commercially available Ajicure PN-H, is achieved at the cost of the gelation time, that is, greater stability is achieved only with an undesirable effect of increase in gelling time. The '12 patent also discloses the use of liquid or solid organic or inorganic acids for surface treatment of the latent hardener (the amine adduct) and for use in the manufacture of the latent hardener. The treatment of hardeners with an acid is designed to neutralize basic active materials on the surface of the hardener particles since the hardener is commonly in a solid state. The organic or inorganic acid is often in a liquid state or in a solution to allow surface treatment, or to make the latent hardener. An abstract in English (produced by Derwent) (adhesion No. 86-229126) for Japanese Patent Application Laid-Open No. S61 -159417 (Japanese Patent No. 92014701) discloses a two part curable epoxy resin composition containing epoxy compounds having an average above one group epoxy in a molecule, thiol compounds containing approximately one thiol group in a molecule such as a hardener (but not a latent one), amines as a curing accelerator, and mercapto-organic acids containing a carboxyl group and a thio group in a molecule such as a curing retarder. With respect to increasing gelation times for two-part epoxy compositions Japanese Patent Publication No. 56057820 discloses such a composition which contains an epoxy compound, a thiol compound as a curing agent, an amine as a curing accelerator, and an acid , added to retard the curing reaction. The composition is not suitable for formulation as a one part composition since the amines used are not latent, and as such cause the composition to cure in a few minutes after the two parts of the composition have been put together. Publication JP '820 appears to be involved with the provision of two-part compositions with increased gelling times achieved when the two parts are joined. This allows the mixed composition to be used for longer periods. Increased gelation times are achieved by the addition of the acid component such as liquid acids and Lewis acids. Publication J P '820 does not appear to be involved with the supply of stable compositions in storage, and does not appear to teach to achieve shelf stability with comitantly with retention of relatively short gelling times. In the electronics industry, it is desirable to provide epoxy-based compositions with custom-made thermal curing profiles for specific application temperature requirements. Such preparation of curing profile helps to maintain the integrity of the electronic components during the process of joining the components to a pcb. Furthermore, it is desirable for such compositions to have pot lives extended at room temperature so that the composition can be repeatedly applied to the surface of the pcb. This prolongs the usable application life of the compositions, thereby ensuring reproducible assortment properties. Advances in the electronics industry have made the precise deposition of surface mount adhesives a critical processing parameter, particularly in view of high production demand and process efficiency. The smaller size microelectronic components of increasing popularity have made the precise deposition of solder or adhesives on circuit boards for chip bonding much more important. When precise adhesive deposition does not occur - either due to inaccurate adhesive deposition technique, or adhesive spraying due to inappropriate rheological properties for the particular application, or both - the surface mounting of components in pcbs may not occur at all. , and even when the assembly occurs, the assembly may not occur in a commercially acceptable manner. With certain applications, such as the applications in the aforementioned electronics industry, it has also become desirable that the epoxy-based compositions have a defined structural integrity. One way to achieve this is through the addition of an agent that confers thixotropy, such as a clay or silica, a large number of which are well known. In fact, Degussa has commercially available a number of calcined silicas treated under the trade name "AEROSI L", and has suggested its use to impart a thickener and thixotropic effect on epoxy resins. See also, C. D. Wright and J. M. Muggee, "Epoxy Structural Adhesives", in Structural Adhesives: Chemistry and Technology, S. R. Hartshorn, Ed., 1 13-79, 131 (1986). Up to now, the desire to balance reactivity with pot life in curable compositions with a one-component epoxy base has been recognized. For example, U.S. Patent No. 3,597,410 (Lieske) discloses a method for prolonging the reaction period of hardenable mixtures based on curable epoxy resins by providing an effective amount of a barbituric compound to retard curing. The compositions are of another form of relatively slow curing at elevated temperatures. The compositions of the '410 Patent include hardenable epoxides containing more than one epoxide group in the molecule, together with an epoxy resin hardener of organic polycarboxylic acid anhydride and an amount of a barbituric compound effective to retard curing. The object of the '410 Patent is said to be to prolong the reaction period or pot life, and to retard the hardening of the epoxy composition at elevated temperatures. U.S. Patent No. 5,130,407 (Lee) relates to an epoxy resin composition used for the manufacture of a heat resistant circuit laminate for printed circuit boards. The composition used is a modified epoxy resin which is obtained by reacting an epoxy resin with a fatty N-heterocyclic compound of a core such as a chain extender, a polyfunctional epoxy resin and curing agents. Barbituric acid is mentioned as a possible chain extender. U.S. Patent No. 5,268,432 (Pan) refers to a heat-resistant adhesive composition containing bismaleimide in a composition that can be modified by barbituric acid to bond a flexible 3-ply printed circuit. U.S. Patent Application No. 2 287 940 relates to a liquid epoxy resin composition for bonding electronic parts to tablets with printed wiring using a dispenser. The composition includes an epoxy resin, an amine agent for curing, an inorganic filler (such as calcined talc) and an organic rheology additive (such as modified castor oil or an organic amide).

European Patent Application No. 459 614 relates to an epoxy resin composition of an epoxy resin, a latent curing agent of the amine type, and a hydrophilic silica. The compositions, which have good shape retention, can be prepared by mixing the components until a thixotropy index of 2 or less is reached. The index of thixotropy is given in the application EP '614 as a ratio of the viscosity measured at 25 ° C and 0.5 rpm on the viscosity measured at 25 ° C and 5 rpm. In addition, an index of the change over time of the viscosity grade ("the rate of change of the thixotropy index") is given in the application EP '614. Without supporting the state of the art it would be desirable to provide epoxy compositions with improved storage stability, such as improved pot life at room temperature and long working lives and relatively short curing times. It would also be desirable to provide compositions with improved rheological properties, such as improved stability of shelf life, particularly with respect to maintaining the yield point over time, maintaining viscosity over time, in addition to storage stability. The compositions having some or all of these properties are very commercially useful, as noted above.

BRIEF DESCRIPTION OF THE INVENTION In a first aspect of the present invention, epoxy / polythiol compositions with improved storage stability are provided, and with long working lives and relatively short curing times at relatively low temperatures. These compositions provide an increase in stability by prolonging pot life without substantially affecting the gelling times. The compositions exhibit good adhesive strengths when cured. More specifically, in this first aspect of the present invention, the epoxy resin compositions include: (a) an epoxy compound having two or more epoxy groups per molecule, (b) a polythiol compound having two or more thiol groups per molecule, (c) a latent hardener, and (d) at least one solid organic acid that is substantially insolubles in a mixture of (a), (b) and (c) above at room temperature Suitably, the solubility of the a mixture of (a), (b) and (c) above is increased to temperature above room temperature. In these inventive compositions, the solid organic acid may have a pKa of less than about 12.0, desirably less than 10, and often less than or equal to about 9.0, such as less than or equal to about 7.5. In addition, the solid organic acid can be selected from at least one of the following solid organic acids: aliphatic, cycloaliphatic, and aromatic carboxylic acids and derivatives of coughs themselves, aliphatic, cycloaliphatic and aromatic quinones and derivatives thereof, phenols and derivatives of the same and aliphatic, cycloaliphatic and aromatic-enolizable compounds and derivatives thereof. Suitably, the selected organic acid is substantially insoluble in a mixture of (a), (b) and (c), at room temperature. The invention also relates to the use of a solid organic acid in the preparation of a one part adhesive composition based on an epoxy resin. The compositions of this first aspect of the invention can be imparted with improved rheological properties by including: (e) an agent imparting thixotropy. The compositions further comprising the agent imparting thixotropy retain their properties such as storage stability and curing at low temperature. In a second aspect of the invention there are provided curable epoxy resin compositions on the one hand comprising: (i) an epoxy component comprising at least one epoxy compound, (ii) a latent hardener component, (ii) a component that confers thixotropy, and (iv) a component of solid organic acid. These compositions show improved rheological properties. The components (i), (ii) and (iv) of this composition correspond to the components (a), (c) and ef acid referred to in component (d) above respectively with respect to the first aspect of the invention. Component (iii) corresponds to the agent (e) that imparts anterior thixotropy. In this second aspect, the solid organic acid is also effective to improve the Theological properties of compositions that do not necessarily contain a polythiol compound. The rheological properties alluded to include those such as improved shelf life stability, particularly with respect to maintaining the yield point over time, maintaining viscosity over time, and pot life at room temperature. In particular, the organic solid acid initially improves the yield point and stabilizes the yield point of the composition over time beyond what is observed in compositions that do not include the solid organic acids used in both aspects of the present invention. The yield point (or effort to yield) can generally be thought of as the minimum effort required to cause a material to flow. The solid organic acid stabilizes both chemical and physical properties of the epoxy resin compositions of the present invention, an effect which is quantifiable by the properties given above. The term "epoxy resin compositions of the present invention" as used herein refers to compositions of the first aspect of the invention including those that further comprise the thixotropy imparting component, and to the compositions of the second aspect of the invention as well. The term also includes such compositions that have one or more additional components added.

The present invention also provides reaction products of the epoxy resin compositions, which exhibit good adhesive strengths when cured. In a practical application, the epoxy resin compositions of the present invention can be used as a sealant resin under load. In this application, the compositions enable a semiconductor device, such as a chip-scale ball array / array array (CSP / BGA) array assembly, which includes a semiconductor chip mounted on a carrier substrate, to be firmly connected to a circuit tablet by short-time heat curing. The invention also provides a method for preparing such epoxy resin compositions, and a method for using such epoxy resin compositions in the fabrication of structures for electronic assembly, such as, for example, surface mount adhesives. The words "comprises / comprising" and the words "having / including" when used herein with reference to the present invention are used to specify the presence of established aspects, integers, steps or components, but do not exclude the presence or addition of one or more other aspects, integers, steps, components or groups thereof. The present invention will be more fully understood by reading the Detailed Description of the Invention, together with the Figures that follow.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is two schematic diagrams A and B showing a substrate with a point of adhesive composition applied thereto and representing point profiles of adhesive compositions, the upper one of which has been stabilized against decreases of the point transferor (Point A) and the lower of which has not been established as such (Point B). Figure 2 is a schematic diagram depicting in an exploded view epoxy resin compositions of the present invention in use for attaching a semiconductor chip to a pcb. Figure 3 is a schematic diagram depicting compositions according to this invention in use for bonding a semiconductor chip to a pcb, between which a sealant has been supplied under load. Figure 4A depicts a time-over-yield plot for a sample composition (Composition 2 of Table 10a below) according to the first aspect of the invention, and including a component conferring thixotropy. Figure 4B depicts a graph of viscosity over time for the sample composition (Composition No. 104 of Table 13 below) according to a first aspect of this invention, and that includes a component that confers thixotropy. Figure 5 depicts a time-over-yield plot for a sample composition (Composition 104 of Table 13 below) according to a second aspect of this invention in contrast to two comparative compositions (Compositions 103 and 105 of Table 13 ).

DETAILED DESCRIPTION OF THE INVENTION Discussion of the epoxy resin compositions of the present invention. The first aspect of the present invention provides an epoxy resin composition comprising an epoxy compound having two or more epoxy groups per molecule, a polythiol compound having two or more thiot groups per molecule, a latent hardener and at least one acid solid organic that is substantially insoluble in a mixture of the epoxy compound, polythiol and hardener. The epoxy resin compositions of the present invention show improved storage stability under ambient conditions and exhibit extended operating temperatures at room temperature. The compositions of the first aspect of the invention comprising a polythiol compound retain good cure at low temperatures, for example 80-85 ° C, even when component (e) the thixotropy-conferring component is added. This composition thus has the desired properties combined: curing at low temperature; storage stability; and Theological stability. The second aspect of the present invention provides an epoxy resin composition comprising an epoxy compound having two or more epoxy groups per molecule, a latent hardener, an agent that confers thixotropy, and at least one solid organic acid that is substantially insoluble desirably in a mixture of the epoxy compound, polythiol and hardener. The epoxy resin compositions of the second aspect of the present invention can be cured in an ordinary manner by heating at a temperature in the range of about 100 to about 180 ° C for a time period of about 0.5 to 60 minutes. However, generally after the application of the composition, a curing time of about 3 minutes at about 125 ° C is sufficient to harden the composition, with full cure observed after about 10 to about 15 minutes at that temperature. Of course, this curing profile may vary depending on the chosen components and the specifications established by the end user. The epoxy resin compositions of the present invention can be used at relatively moderate temperatures and short-time curing conditions, and thus achieve very good productivity. The compositions show good curability at moderate temperatures, and can be formulated as either one-part or two-part compositions. The epoxy resin compositions of the first aspect of the present invention can be produced by the method illustrated in Examples 1 to 49 below. That is to say, to mix the solid organic acid, the latent hardener, the epoxy, the polythiol and optionally the component that confers thixotropy. Desirably, the solid organic acid must be added to the composition before the addition of the latent hardener.

The epoxy resin compositions of the second aspect of the present invention can be produced by the method illustrated in Sections V and VI below. Desirably, the acid component is combined with the epoxy component before the addition of the tixotropta-conferring component.

Discussion of the epoxy resin component; The epoxy component for the epoxy resin compositions of the present invention can be selected from any polymeric epoxide having an average of two or more epoxide groups per molecule, including polyglycidyl ethers of polyhydric phenols, for example polyglycidyl ethers of bisfetiol A, bisphenol F, bisphenol AD, catechol, resorcinof. The epoxy compounds obtained by reacting polyhydric alcohols such as butanediol or polyethylene glycol or glycerin with epichlorohydrin are also suitable. Epoxidized (poly) olefin resins, epoxidized phenolic novoiac resins, cresol novolac resins and cycloaliphatic epoxy resins can also be used. Also included are the glycidyl ether esters, such as those obtained by reacting hydrocarboxylic acid with epichlorohydrin, and polyglycidyl esters, such as those obtained by reacting a polycarboxylic acid with epithorhydrin. Also suitable are epoxy resins modified with urethane. Other suitable epoxy compounds include potypoxy compounds based on aromatic amines and epichlorohydrin, such as N, N'-digiicidyl-aniline; N, N, -dimethyl-N) N'-diglycidyl-4,4'-diaminodiphenyl methane; N, N, N ', N'-tetraglycid »l-4,4'-diaminodiphenyl methane; N-diglycidyl-4-aminodiphenyl glycidyl ether; and N, N, N ', N, -tetraglycidyl-1,3-propylene-4-aminobenzoate. Combinations of these epoxy compounds can be used. Among the epoxy resins suitable for use herein are the derivatives of poiiglicidii of phenolic compounds, such as those commercially available under the tradenames EPON 828, EPON 1001, EPON 1009, and EPON 1031, from Shell Chemical Co .; DER 331, DER 332, DER 334, and DER 542 of Dow Chemical Cp .; and BREN-S from Nippon Kayaku, Japan. Other suitable epoxy resins include polyepoxides prepared from polyols and the like and polyglycidyl derivatives of phenol-formaidehyde novolacs, the latter of which are commercially available under the tradenames DEN 431, DEN 438, and DEN 439 from the Dow Chemical Company. . The cresol analogs are also commercially available as ECN 1235, ECH 1273, and ECN 1299 from Ciba-Geigy Corporation. SU-8 is a bisphenol type A epoxy novolac available from Intrez, Inc. Also useful in this invention are the additives of potassium glycols, aminoalcohols and poficarboxylic acids, commercially available resins including GLYAMINE 135, GLYAMINE 125, AND GLYAMINE. 115 of FIC Corporation; ARALDITE MY-720, ARALDITE 0500, and ARALDITE 0510 from Ciba-Geigy Corporation and PGA-X and PGA-C from Sherwin-Williams Co. Epoxy resins are discussed in U.S. Patent No. 5,430,112 whose entire contents are incorporated by this one to the present. Suitable reactive diluents which include monofunctional or certain multifunctional epoxy resins may be included within the epoxy component. The reactive diluent should have a viscosity that is less than that of the epoxy compounds within the epoxy component having at least two epoxy groups. Ordinarily, the reactive diluent should have a viscosity of less than about 250 mPa.s (cPs). In the event that a monofunctional epoxy resin is included within the epoxy component as a reactive diluent, such a monofunctional epoxy resin should be employed in an amount of up to about 50 parts based on the total epoxy resin component. The monofunctional epoxy resin should have an epoxy group with an alkyl group of about 6 to about 28 carbon atoms, examples of which include alkyl glycidyl ethers of Ce-C28, esters of glycidyl fatty acid of C6-C2e. and alkyl phenol glycidyl esters of Cß-C28. Commercially available monofunctional epoxy resin reactive diluents include those from Pacific Epoxy Polymers, Richmond, Missouri, under the tradenames PEP-6770 (glycidyl ester of neodecanoic acid), PEP-6740 (phenyl glycidyl ether) and PEP-6741 (ether) butyl glycidyl). Commercially available reactive diluents include those from Pacific Epoxy Polymers, under the tradenames PEP-6752 (trimethylol propane tricyclic ether) and PEP-6760 (diglycidyl aniline). The epoxy resin is suitably present in amounts of from about 40 to about 80% based on the total weight of the composition, such as about 45 to about 70%. It should be noted that the amounts of a given component generally mentioned apply to the compositions of the first and second aspects of the invention.

Discussion of the polythiol component; The polythiol component for compositions of the first aspect of the invention can be selected from any mercapto compound which has two or more thiol groups per molecule, such as trimetillol propane tris (β-mercaptopropionate), trimetillol propane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate), pentaerythritol tetrakis (β-mercaptopropionate), dipentaerythritol-poly (β-mercaptopropionate), ethylene glycol bis (β-mercaptopropionate), and alkyl polyols such as butane-1,4-dithiol, hexane-1,6-dithiol, and aromatic polythiols such as p-xylenedithiol and 1, 3,5-tris (mercaptomethyl) benzene. The polythiols can be added in amounts of from about 25 to about 50% based on the total weight of the composition, such as about 33 to about 40%. Suitably the ratio of the epoxy compound to the polythiol compound in the composition is such that the ratio of epoxy equivalents to thiol equivalents is about 0.5: 1 to about 1.5: 1, such as about 0.75: 1 to about 1.3: 1. The politioi component described above can optionally be included in the compositions of the second aspect of the invention. Polythiol compounds suitable for use in the invention are referred to in U.S. Patent No. 5,430,112.

Discussion of the latent hardening component: The epoxy resin compositions of the present invention include at least one latent hardener, which is typically heat activatable. Such a latent hardener must be substantially inactive at room temperature, but must be capable of activation at temperatures above 50 ° C to effect the heat cure of the epoxy resin. Suitable hardeners are described in British Patent 1, 121, 196 (Ciba-Geigy AG), European patent application 138465A (Ajinomoto Co.) or European patent application 193068A (Asahi Chemical), whose description of each are incorporated expressly by this to the present by reference. Other hardeners suitable for use herein include those commercially available, such as Anchor Chemical 2014. British Patent 1, 121, 196 discloses a reaction product of phthalic anhydride and an aliphatic polyamine, more particularly a reaction product of acid proportions. approximately equimolar phthalic and triamine diethylamine. A hardener of this type is commercially available from Ciba-Geigy AG under the trademark CIBA HT9506. Still another type of latent hardener is a reaction product of (i) a polyfunctional epoxy compound, (ii) a Imidazole compound such as 2-ethyl-4-methylimidazole and (iii) italic anhydride. The polyfunctional epoxy compound may be any compound having two or more epoxy groups in the molecule as described in the Patent of E. U-, No. 4,546,155, the disclosure of which is expressly incorporated herein by reference. A hardener of this type is commercially available from Aginomoto Co., Inc. under the trademark AGICURE PN-23, believed to be an adduct of EPON 828 (epoxy equivalent of bisphenot 184-194 epoxy resin, commercially available from Shell Chemical Co.), 2-ethyl-4-methylimidazole and phthalic anhydride. Other suitable hardeners are those given in U.S. Patent No. 5,077,376 and those of the '112 Patent called "latent amine adduct accelerators" or the reaction product of a compound having one or more isocyanate groups in its molecule with a compound having at least one primary or secondary amino group in its molecule. Additional latent hardeners include 2-heptadeoylimidazole, 2-fenif-4,5-dihydroxymethylimidazole, 2-fem-4-benzyl-5-hydroxymethylimidazole, 2,4-diamino-8-2-methylimidazole- (1) -ethyl-5- triazine, additional products of triazine with isocyanuric acid, succino hydrazide, adipo hydrazide, isoftolohydrazide, o-oxybenzohydrazide and salicylohydrazide. Other commercially available latent hardeners from Ajinomoto include AMfCURE MY-24, AMICURE GG-216 and AMICURE ATU CARBAMATO. In addition, NOVACURE HX-372, (commercially available from Asahi Kasei Kogyo, K.K. Japan) can also be used. See European Patent Application No. 459 614 discussed above. The latent hardener may suitably be present in amounts of from about 5 to about 45 parts, desirably from about 1 to about 30 parts, more desirably from about 10 to about 20 parts by weight per 100 parts of the epoxy resin. The latent hardener can be prepared by recognized industrial methods, or it can be obtained commercially where it is available.

Discussion of the solid organic acid component The solid organic acids useful in the epoxy resin compositions of the present invention can also include compounds that do not have one or more acid functional groups, but that have an acidic proton or have an acidic nature, for example , enotizabies materials. The term "atiphatic" as used herein refers to suitable straight or branched chain C 1 -C 40 alkenyl, alkyl or alkynyl which may or may not be interrupted or substituted by one or more heteroatoms, O, N, or S, and fused ring systems containing one or more of these aromatic groups fused together. The term "carboxylic acid" includes acids having one or more carboxylic groups, and if two or more are present, one or more may be optionally esterified, the ester group suitably comprising an alkyl group of suitably an alkyl group of C? C4 The term "quinone" includes compounds having one or more quinone groups and the terms aliphatic, cycloatiphatic, and aromatic when used to describe quinones are used to refer quinones to which the aliphatic, cycloaliphatic and aromatic groups or combinations of these groups are joined by direct ligation or ring fusion. The term "phenol" includes compounds having one or more phenolic groups and the terms aliphatic, cycloaliphatic, and aromatic when used to describe phenols are used to refer to phenols to which the aliphatic, cycloaliphatic and aromatic groups or combinations of these groups are joined by direct ligation or ring fusion. The term "enolizable" includes compounds that have one or more enolizable functional groups. The term "derivatives" refers to substitutions in one or more positions (including directly in a heteroatom) with one or more of the following: C1-C20 alkoxy, CrC20 alkyl, C? -C20 alkenyl, a carbonyl group, a thiocarbonyl group such as group -C = S, a carboxylic group, a C1-C4 alkyl group, which further contains up to three N atoms, phenyl, C1-C4 alkylphenyl, or Ci-Cao alkenylphenyl ", OR, NR, SR, SSR, wherein R is a phenyl, an aliphatic, a cycloaliphatic or an aromatic group, each of which can optionally be further substituted at any position with one or more of C 1 -C 4 alkyl, OH, halogen ( F, Br, Cl, I), phenyl, C 1 -C 4 alkylphenyl, or C 1 -C 4 alkenylphenyl, or OR where R is phenyl, a carboxyl group, carbonyl, or an aromatic group and R is optionally substituted with C 1 alkyl -C4, OH, or halogen, or nitro, nitri, or halogen; or nitro, nitrile, or halogen. Examples of useful solid organic acids are phenols, quinones, carboxylic acids and enolizable materials. An example of an enolizable material is barbituric acid. The term "acid" includes poiimeric acids including polycarboxylic acids and polyphenols. The solid organic acids useful in the first aspect of the invention should be substantially insoluble in a βpoxy / potitiol / latent hardener resin composition at temperatures in the range of about 5 ° C, to about 35 ° C, such as about 15 ° C. at about 30 ° C. For those of the second aspect of the invention the solid organic acid component should be substantially insoluble in a mixture of the epoxy component, the latent hardener and thixotropic component at temperatures in the range of about 5 ° C, to about 35 ° C, tat as about 15 ° C to about 30 ° C. The solid organic acid should be present in concentrations between about 0.1 to 25 parts by weight per 100 parts of the epoxy resin in the epoxy resin compositions of the present invention . While in a first aspect of the invention the pKa of a solid organic acid must be less than that of the particular polythiol used in the composition, however the pKa of the organic acid The solid chosen for the epoxy resin compositions of the first and second aspects of the invention should not be so low as to react with the epoxy compound. The solid organic acid must also have a degree of insolubility in the composition of the first aspect of the invention so that it can act as a reservoir allowing only sufficient acid to be solubilized thereby neutralizing any soluble hardener and / or a polythiol reaction product. and the hardener. Although you do not want to be limited to any theory, you think that, in this way, the solid organic acid can act to avoid the chemical reaction between the soluble hardener and the polyolol component in addition to the hardener to the composition and thus stabilize the composition over time. The solid organic acid which is substantially insoluble, thus remains in effective amounts at temperatures below the elevated activation temperatures necessary to initiate the curing of the composition. Temperatures below the activation temperature referred to include temperatures at or about room temperature. In other words, an amount of the solid organic acid remains in the solid form, the amount being effective to stabilize the composition. Thus, the curing initiator species present in the composition are neutralized by the solubilized acid, in a continuous base. Of course, depending on the particular acid and hardener the stabilization time may vary. Those skilled in the art will readily understand how to vary that time as desired by making appropriate selections of the particular components and using suitable amounts thereof. Solid organic acids that are suitable for use in the compositions of the first aspect of the invention should have a pKa less than the pKa of the polythiol component. Typical thiols have pKas within the range of about 8-1 12. Desirable acids are those that have a pKa less than or equal to about 12.0, desirably less than or equal to 10.0, and often less than or equal to about 9.0 , as less than or equal to approximately 7.5. Where a combination of two or more solid organic acids is used the pKa of the combination must be less than or equal to about 12.0. Ordinarily, at least one of the acids in the solid organic acid component has a pKa lower than that of the polythiol, that is, less than or equal to about 12.0, and suitably less than or equal to about 10.0 and often less than or equal to about 9.0 such as less than or equal to about 7.5. although polythiol is not necessarily a component of the compositions of the second aspect of the invention, it is desirable that acids having the pKa values described above are also used in the second aspect. In the first aspect of the invention the solid organic acid can preferably react with the soluble latent hardener until the concentration of the acid has been exhausted, at which time the latent hardener can react with the potitiot in epoxy / polythiol compositions of the invention for Begin the curing of the composition. In the second aspect of the invention the solid organic acid component remains substantially insoluble in the compositions so that the solid organic acid is present in an amount effective to stabilize the rheological properties of the composition.

Some rheological stabilization can be imparted by neutralization of the soluble latent hardener by the soluble acid. As described above for the first aspect the effective amount of the insoluble solid organic acid in the composition preferably neutralizes at least some curative initiator species in the composition, while retaining a sufficient deposit of solid acid which can be solubilized to replace the soluble acid consumed in the neutralization. It is desirable that the acid have an average particle size in the range of about 0.1 to about 500 microns, suitably about 5 to about 100 microns, and desirably about 10 to about 50 microns. It has been found that particle size influences the effect of solid organic acid as discussed in more detail below. The stabilizing effect is achieved in the compositions of the first aspect of the invention without substantial loss of ability to cure (gel) at temperatures of 80-85 ° C in a reasonable time. The amount of the chosen acid will be influenced by its hydrogen equivalent, degree of solubility and particle size. Certain combinations of acids (such as carboxylic acids and quinones) may show increased effects on the acids used Individually. The solid organic acid can be selected from carboxylic acids of the general Formula I: RiCOaH wherein: trans-CH? CHCO2H, -CH = CHCO2R [R is CH3], -CH2C (OR ') (CO2RB) CH2CO2R "', [R 'is H, C1-C10 alkyl, Ar], R" is H, Ct-Cto alkyl, Ar], [R "'is H, C1-C1 alkyl, Ar], Cu-C2 alkyl, - (CH2)" CO2H. {n is 1-9], - (CHR ) nCO2H [R is H, OH, n is 1 or 2], -CH (OR ') R "fR" is H, alkyl, C-Realkyl, -C10, Ph], -CH = CH-Ar, or Other suitable compounds are benzoic acids of the general Formula II: wherein: R1 is H, alkyl, haloalkonium such as CX3fX is F, Cl, 8r, l], alkenyl, OH, OR [R is alkyl, Ph, Bn, Ar], -SS-Ar-CO2H, -SS- Ar, -SR [R is H, alkyl, haloalkyl, Ph, Bn, Ar], Ph, Bn, Ar, CO2RER is H, alkyl, Ph, Bn, Ar], CO.RJR is H, alkyl, Ph, Bn , Ar], NO2, R2 is H, alkyl, haloalkulto tat as CX3 [X is F, Ct, Br, fj, ayane, Ph, Bn, Ar, OH, OR, [R is afquy, Ph, Bn, Ar] , -CH2Ar, NO2, CO.R [R is C1-C10 alkyl, Ph, Bn, Ar], CHO, CO2R [R is H, alkyl, haloafquifo, Ph, Bn, Ar], or R3 is H, alkyl, haloalkyl such as CX3. { X is F, Cl, Br, I], alkenits, OH, OR [R is alkyl, Ph, Bn, Ar] Ph, Bn, Ar, alkyl, CHO, CO.RfR is alkyl, Ph, Bn, Ar], CO2R [R is H, alkyl, Ph, Bn, Ar ] NO2; R4 is H, alkyl, haloalkyl such as CX3 [X is F, Cl, Br, fj, afkenyl, OH, OR [R is affy, Ph, Bn, Ar] NO2, CO.R [R is alkyl, Ph, Bn, Ar], CHO, CO2R.R is H, alkyl, Ph, Bn, Ar], Ph, Bn, Ar; Rs is H, alkyl, haloalkyl such as CX3 fX is F, Cl, Br, I], alkenyl, OH, OR [R is alkyl, Ph, Bn, Ar], Ph, Bn, Ar, CHO, CO.RfJ is I rent, Ph, Bn, Ar], CO2R [R is H, alkyl, Ph, Bn, Ar], NO2; Quinones of the general Formula III are also suitable for use in the composition of the present invention: where R? > R ?, Rs, and R are independently H, alkyl, haloalkyl, alkenyl, OR [R is H, alkyl, Ar, Ph, BnJ CN, Ph, Ar. Phenoles of the general Formula IV; wherein: R is H, OH; Ri is H, aftyl, haloatchyl such as CX3 [X is F, Cl, Br, l], alkenyl, Cl, F, Br, I, CN, OH, OR [R is alkyl, Ph, Bn, Ar], NO2 , CO2R [R is alkyl, Ph, Bn, Ar], CHO, CO2R [R is H, alkyl, Ph, Bn, Ar], PhOH, R2 is H, alkyl, haloalkyo, alkenyl, OH, OR, [R is alkyl, Ph, Bn, Ar], Ph, Bn, -CH2Ar, CN, F, Cl, Br, I, R3 is H, alkyl, haloalkyl such as CX3 [X is F, Cl, Br, I], alkenyl, NO2, CO.R [R is alkyl, Ph, Bn, Ar] CHO, CO2R [R is alkyl, Ph, Bn, Ar], OH, OR [R is alkyl, Ph, Bn, Ar], Ar, Bn, Ph, wherein: Rβ, and R7 are independently H, alkyl, haloalkyl, alkenyl, OH, ORfR is alkyl, Ar, Ph, Bn]; R4 is H, alkyl, haloalkyl, alkenyl, OH, OR [R is alkyl, Ph, Bn, Ar], F, Cl, Br, I, CN, Ph, Bn, -CH2Ar; Rs is H, alkyl, haloalkyl such as CX3 [X is F, Cl, Br, I], alkenyl, F, Cl, Br, I, CN, OH, OR [R is alkyl, Ph, Bn, Ar], NO2, CO. R [R is alkyl, Ph, Bn, Ar], CHO, CO2R [R is H, alkyl, Ph, Bn, Ar], PhOH, provided that a compound of the general Formula IV having at least one phenolic group present is selected. Enolizable materials such as those of the general Formula V: wherein: Ri or R2 are NR'CO.NR "R" '[R' is H, alkyl, Ph, Ar, R "is H, alkyl, Ph, Ar, R" 'is H, alkyl, Ph, Ar , R "'is H, alkyl, Ph, Ar], OR [R is H, alkyl, Ph, Ar].

X is (CH2) n, C (R) 2 [R is aftyl, Ph, Ar, CN], O, S, NRfR is H, alkyl, Ph, Ar], n is 0-10, can also be used. Et enolizabie material can be selected from the compounds of the general Formula VI: where: (a) X1 = X2 = NH, R = H, R? = O, n * 1; or (b) X ^ Xa ^ NH, R? = O, n is zero so that the cyclic structure has a ring of five members; or (c) X? * X2 = 0, R = H, Rt = (CH3) 2, n = 1; or (d) X? = X2 = O, R = Ph, R? = (CH3) 2, n = 1; they are also suitable for use in the present invention.

In Formulas I through VI above, Ar represents substituted phenyl, substituted or unsubstituted bicyclic or multicyclic aromatic compounds, v. g., naphthalene, substituted naphthalene, and similar ios and Ph is phenyl. Bn is a substituted or unsubstituted benzyl group. Alkyl can be straight or branched chain C 1 -C 20 alkyl, suitably Haloalkyl alkyl should be interpreted as an alkyl substituted one or more times by one or more halogens. Alkenite can be straight or branched chain C2-C2o alkenyl, suitably C2-C10. The groups in which affyl most frequently represents C 1 -C 5 alkyl include the group OR - such as in Formula III, and in the definition of R 'in the group - CH (OR') R * in Formula I. The term "substituted" includes the substitution of the derivatives listed above. The solid organic acid can be selected from, for example: 4-nitroguayacol, 3,4,5-trimethoxy benzoic acid, hexachlorophene, 3,5-dinitrosalicylic acid, 4,5,7-trihydroxyflavanone, 2,2-dithiosalicylic acid, phlorogicin, fumaric acid, 3,4-dihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, trotox, pamico acid, ascorbic acid, saficilic acid, citric acid, 3,4-dihydroxy cinnamic acid, 2,3-dicyanohydroquinone , barbituric acid, tetrahydroxy-p-benzoquinone, parabánfco acid, fenit boronic acid, 5-phenyl acid of Meldrum and Meldrum acid. Of these acids those that exhibit a greater stabilizing effect are barbituric acid, trolox, and fumaric acid, with barbituric acid being the one that exhibits a better stabilizing effect. A number of solid organic acids which are useful in the present invention are discussed below, and to facilitate the discussion herein only, they have been classified into four different groups.

EXAMPLES OF SOLID ORGANIC ACIDS Functional Groups Fenóllcos Functional Groups Carboxy 4-nitroguayacol 3,4,5-trimethoxy benzoic acid hexachlorophene 3,5-dinitrosalicylic acid 4,5,7-trihydroxyf-vanone 2,3-dioctosphite acid ftorogfucinof acid fumaric acid 3 , 4-dihydroxy benzoic acid 3,4,5-trihydroxy benzoic Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) pamico acid ascorbic acid salicylic acid citric acid 3,4-dihydroxy cinnamic acid Quinona Derivatives Enolizable Acids 2,3-dicyanohydroquinone barbituric acid tetrahydroxy-p-benzoquinone parabanic acid phenyl boronic acid 5-phenyl acid Meldrum Meldrum acid Discussion of the Thixotropy-conferring component: The thixotropy-conferring component which is an optional "(e) * component of the composition of the first aspect of the invention, and which is component" (iii) "of the compositions of the second aspect of The invention may often include reinforcing silicas, such as fused or calcined silicas, and may be treated or untreated to alter the chemical nature of its surface Virtually any fused or calcined reinforcing silica may be used. treated silicas treated with polydimethylsiloxane and silicas treated with hexamethyldisilazane, such treated silicas are commercially available, such as from Cabot Corporation under the trade name CAB-O-SIL NB-TS and Degussa Corporation under the trademark AEROSIL, such as AEROSIL R805. Of the untreated silicas, amorphous and hydrated silicas can be used. For example, commercially available amorphous silicas include AEROSI L 300 with an average particle size of the primary particles of about 7 nm, AEROSI L 200 with an average particle size of the primary particles of about 12 nm, AEROSIL 130 with a size average of the primary particles of approximately 16 nm; and commercially available hydrated silicas include NIPSIL E150 with an average particle size of 4.5 nm, NIPSIL E200A with an average particle size of 2.0 nm, and NIPSIL E220A with an average particle size of 1.0 nm, (manufactured by Japan Silica Kogya Inc. .). The desirable ones also have a low ion concentration and are relatively small in particle size (v. Q of the order of about 2 microns), such as the silica commercially available from Admatech, Japan under the trade name SO-E5. Other desirable materials for use as the component conferring thixotropy include those constructed of, or containing, aluminum oxide, silicon nitride, aluminum nitride, and aluminum nitride coated with silica. The agent which confers thixotropy should be used in an amount within the range of 5 to 40 parts, such as about 15-25 parts, per hundred parts of the epoxy component depending on the reoiogy requirements of the application of use finat. The particular set of rheological properties developed for an adhesive may tend to change over time. These properties impact the shelf stability of the adhesive composition, and can affect the ability of the adhesive assortment in its finat applications. Many commercially available adhesives, including normally available epoxy based adhesives, are inherently chemically unstable and, even under refrigerated storage conditions recommended by the manufacturer, may suffer from unstable rheological properties (such as decreasing yield point over time). The degree of this instability often depends on the temperature. Such crossover point instability can affect the composition's assortment ability over time and can result in weaker bond strengths due to changes in the point profile. More specifically, in the context of curable one-part epoxy resins, viscosity increases are often seen over time, with the increase in viscosity being drastic often in a relatively short period of time. In such a case, pot life can be considered very short for wide range commercial application. Such viscosity increases are due at least in part to the start of the polymerization initiation. The dropping point decreases can be observed that also occur over time in such compositions. Such decreases of yield point are prevalent particularly in those compositions whose structure has been increased by the addition of thickeners or components conferring thixotropy. As noted, these changes in rheological properties over time adversely affect the shelf life stability of the adhesive composition. The epoxy resin compositions of the invention comprising this thixotropic conferring agent typically have ceding points in the range of about 30-700 Pa, suitably 150-450 Pa, and a viscosity measured at a temperature of about 25 ° C in the range of approximately 1-5 ° Pa.s, suitably 1 to 25 Pa.s, desirably 1-10 Pa.s. The yield point and viscosity are substantially maintained within those respective ranges over time.

Other ditties; Any number of conventional additives may also be added to the epoxy resin compositions of the present invention including fillers, thixotropy imparting agents (if not already present), reactive substituents, non-reactive diluents, pigments, flexibilizers, and the like, depending on the Use intended finat of the composition.

End-use applications of compositions of the invention: The epoxy resin compositions of the present invention are suitable for use in any conventional application of epoxy compositions, such as adhesive or coating agents. They can be used generally in the electronics industry, including the microelectronics industry. A commercial use of epoxy resins is to attach a surface mount semiconductor device to a pcb in a chip bonding application. A method for using a composition of the invention to achieve such a result typically includes the steps of: (i) filling an appropriate location on a carrier substrate with a sufficient amount of the composition, (ii) placing on the location supporting the composition a electronic component, (iii) equalizing the electronic component with the carrier substrate, and (iv) exposing the matched electronic component / carrier substrate assembly to favorable conditions for curing the composition. Another commercial use is as a sealer under load to seal the space between a semiconductor, a device electrically connected to a circuit board. The epoxy resin compositions of the invention are suitable for this purpose. A method of filling underneath a space between an electronic component and a carrier substrate while the electronic component is mounted on the carrier substrate typically includes passing a quantity of an epoxy resin according to the present invention to the space between the electronic component and the carrier substrate, and it is also provided to expose the epoxy resin compositions to a condition that effect curing. In use, the epoxy resin compositions of the present invention can be applied to a substrate in any conventional manner. Suitable modes of application include syringe assortment, pin transfer, screen printing, and other conventional equipment for adhesive assortment. In a chip sticking application and with reference to Figure 1 (Schematic diagrams A and B showing a substrate with a point of adhesive composition applied to it), a high yield point produces a conical point, which retains its shape over time (Point A). Shape retention occurs because the yield point is large enough to withstand the force of gravity with respect to an application usage time scale. A yield point that is very low results in a point that spills over time giving a low, rounded appearance. (Point B) If the point spills too much in that period can cover the welding areas and avoid good contact of a semiconductor chip with the pcb. Referring to Figure 2 which shows a mounted structure in which an epoxy resin composition 4 according to a second aspect of the invention has been provided, on a carrier substrate 1 (eg, a pcb) between the welding zones 3 . The semiconductor chip 2 is placed on the location of the carrier substrate 1 on the cuat, the epoxy resin composition 4 has been added, and the carrier substrate and semiconductor substrate are thereafter matched. Figure 2 shows the composition 4 of epoxy resin having been dispensed into the carrier substrate 1. In certain cases it may be desirable to apply the composition on the semiconductor chip 2 instead of, or apply the composition on both, the carrier substrate 1 and the 2 semiconductor chip. The epoxy resin composition is then exposed to appropriate conditions to effect curing to bond the carrier substrate and the semiconductor chip together. Ordinarily, these conditions include a heat curing mechanism. In order to improve viability, the space between the semiconductor chip 2 and the carrier substrate 1 can be suitably sealed with a sealant 10 under the load which can be an epoxy resin composition of the present invention. The epoxy resin compositions of the present invention may be used in conjunction with, or in place of, conventional sealers filled below such as any commercially available from Loctite Corporation, including the Loctite product number 3150. (See Figure 3, and the description below). The cured product of the sealant deposited below must completely fill that space. The carrier substrates can be constructed of ceramic substrates of AI2O3, SiN3 and mullite (AI2O3-SIO2): substrates or ribbons of heat resistant resins, such as polyimides; epoxy reinforced with glass; ABS and phenolic substrates that are also commonly used as circuit boards or tablets; and the similar ones. In Figures 2 and 3, the welding zones are represented as the electrical connection means. In the arrangement of Figure 3 the semiconductor device 20 is one formed by connecting a semiconductor chip (called a bare chip) 22, such as LSI, to a carrier substrate 21 using an epoxy resin composition of the invention and sealing the space therebetween. with resin 23. This semiconductor device is mounted in a predetermined position of the circuit board 5, and electrodes 8 and 9 are electrically connected by a suitable connecting means such as welding. In order to improve viability, the space between the carrier substrate 21 and the circuit board 5 is sealed with a sealant filled below and the cuat is the cured product of a thermoset resin composition. The cured product 10 of the thermoset resin composition does not need to completely fill the space between the carrier substrate 1 and the circuit board 5, but can fill it to a degree that relieves the stresses caused by the thermal cycles. The cured reaction products of the epoxy resin compositions of the present invention demonstrate excellent adhesive strength, heat resistance and electrical properties, and acceptable mechanical properties, such as chemical resistance, moisture resistance and similar cough, for the applications for which are used in the present. Although the present invention has been explained in detail above, the following examples further illustrate the benefits and advantages achieved by the compositions of the invention.

EXAMPLES The materials used in the following non-limiting examples are referred to as follows: Epoxy Resins "EP-828" - Epikote 828 (trade name of Shell Chemical Co.) "EPON 862" is an epoxy resin of bisphenol F (trade name of Shell Chemical Co.) "RE-310S" - (trade name of Nippon Kayaku) DEN 438 is an epoxy novolac resin, available from Dow Chemical Company Polythiol Compounds "TMP - trimethylolpropane tris (β-mercaptopropionate) (product of Aldrich Chemical Co.)" PETMP "- pentaerythritol tetrakis (β-mercaptopropionate) (product of Evans Chemetics) Latent hardeners "PN-23" - AJICURE PN-23 (trade name, product of Ajinomoto Co., Inc.) "PN-H" - AJICURE PN-H (trade name, product of Ajinomoto Co., Inc.) Organic Acids Solid Trolox - Trolox is 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid. (Trolox is a registered trademark and product of Aldrich Chemical, Co.) j . Preparation of Compositions with Epoxy Base of Curing at Low Temperature We prepare a control composition of an epoxy resin, a polythiol and a latent hardener. The gel time at 85 ° C and room temperature (and in some cases at 40 ° C) and stability were recorded. The corresponding compositions containing a solid organic acid of the invention were then prepared. Because the solid organic acid is substantially insoluble in the epoxy / polythi mixture it was evenly dispersed before the addition of the hardener. As stated above, in the following examples where a solid organic acid is added we add it to the epoxy-polythiol mixture before the addition of the latent hardener. We prepare the following compositions: Example 1 - Control for cough Examples 2 to 4. 1) We add 4 parts by weight of AJICURE PN-H to a mixture prepared by mixing 100 parts by weight of Epikote 828 and 75 parts by weight of trimetilloi propane tris (β-mercaptopropionate). The components were thoroughly mixed and degassed to obtain composition 1 of control epoxy resin (Table 1a). Composition 1 (Table 1b) was observed to have a gel time of 70 seconds at 85 ° C and an RT stability of 30 days. The stability of the composition at 40 ° C was 4 days.

Examples 2 to 4 2) Preparation 2 of epoxy resin was prepared in the same manner as composition 1 (Table 1 a) with the addition of 0.5 parts by weight of fumaric acid. It was observed that composition 2 (Tabía 1b) has a gel time of 95 seconds at 85 ° C and an RT stability of more than 58 days. The stability of the composition at 40 ° C was 11-14 days. 3) Composition 3 (Table 1a) was prepared as in Example 1 with the addition of 0.5 parts by weight of barbituric acid. It was observed that composition 3 (Table 1b) has a gef time of 160 seconds and an RT stability of more than 58 days. The stability of the composition at 40 ° C was greater than 42 days. 4) The composition 4 (Table 1a) was prepared cpmo in Example 1, but without the addition of 0.5 parts by weight of 3,4-dihydroxy cinnamic acid (Table 1b). It was observed that it has a gel time of 135-160 seconds and an RT stability of more than 42 days. The stability of the composition at 40 ° C was greater than 18-21 days.

Example 5 - * Control for Examples 6 to 11. 5) The composition 5 was prepared by mixing 100 parts by weight of Epikote 828 with 75 parts by weight of trimethylolpropane tris (β-mercaptopropionate) and adding 25 parts by weight of A to this ICURE PN-23. The components were mixed thoroughly and degassed to obtain the control composition of epoxy resin? (Table 1a). Composition 5 (Table 1b) was observed to have a gel time of 12 seconds at 85 ° C and an RT stability of 3 to 16 hours. The stability of the composition at 40 ° C was less than 16 hours.

Examples 6 to 11. 6) The composition 6 of epoxy resin (Table 1a) was prepared as in Example 5 with the addition of 12 parts by weight of fumaric acid. It was observed that the composition 6 (Table 1b) has a gel time of 50 seconds at 85 ° C and an RT stability of more than 30 days. The stability of the composition at 40 ° C was greater than 15 days. 7) Composition 7 (Table 1 a) was prepared as in Example 5 with the addition of 12 parts by weight of burbituric acid. It was observed that composition 7 (Table 1b) has a gei time of 150 seconds at 85 ° C and an RT stability of more than 30 days. The stability of the composition at 40 ° C was greater than 12 days. 8) The composition 8 (Table 1a) was prepared as in Example 5 with the addition of 8 parts by weight of salicylic acid. It was observed that composition 8 (Table 1b) has a gel time of more than 300 seconds at 85 ° C and an RT stability of 4-5 days. The stability of the composition at 40 ° C was less than 24 hours. 9) Composition 9 (Table 1 a) was prepared as in Example 5 with the addition of 8 parts by weight of phenyl boronic acid. It was observed that composition 9 (Table 1 b) has a gel time of 120 seconds at 85 ° C and an RT stability of 4-5 days. The stability of the composition at 40 ° C was less than 24 hours. 10) The composition 10 (Table 1 a) was prepared as in Example 5 with the addition of 8 parts by weight of Meldrum 5-phenyl acid. It was observed that the composition 10 (Table 1b) has a gel time of more than 300 seconds at 85 ° C and an RT stability of more than 9 days. 1 1) The composition 1 1 (Table 1a) was prepared as in Example 5 with the addition of 8 parts by weight of pamico acid. It was observed that the composition 1 1 (Table 1 b) has a gel time of more than 25 seconds at 85 ° C and an RT stability of 6-7 days.

Example 12 - Control for Examples 13 v 14. 12) The epoxy resin composition 12 was prepared by mixing 100 parts by weight of Epikote 828 with 75 parts by weight of trimethylthopropane tris (β-mercaptopropionate) and adding 2 parts by weight thereto of AJICURE PN-23. The components were mixed thoroughly and degassed to obtain the control composition of epoxy resin (Table 2a). Composition 12 (Table 2b) was observed to have a gel time of 90 seconds at 85 ° C and RT stability of 2-3 days. The stability of the composition at 40 ° C was less than 24 hours.

Examples 13 v 14. 13) The composition 13 (Table 2a) was prepared as in Example 12 with the addition of 1 part by weight of phloroglucinol. It was observed that composition 13 (Table 2b) has a gel time of 300 seconds at 85 ° C and an RT stability of 15 days. 14) The composition 14 (Table 2a) was prepared as in Example 12 with the addition of 1 part by weight of tartaric acid. It was observed that composition 14 (Table 2b) has a gef time of 200 seconds at 85 ° C and an RT stability of 10-13 days.

Example 15 - Control for Examples 16 to 18. 15) The epoxy resin composition 15 was prepared by mixing 100 parts by weight of Epikote 828 with 33 parts by weight of pentaerythritol tetrakis tris (β-mercaptopropionate) and adding 20 parts to this mixture. in weight of AJICURE PN-23. The components were mixed thoroughly and degassed to obtain the control composition of epoxy resin (Table 2a). The composition 15 (Table 2b) was observed to have a gel time of 15 seconds at 85 ° C and a stability RT of less than 16 hours. The stability of the composition at 40 ° C was less than 16 hours.

Examples 16 to 18. 16) The composition 16 (Table 2a) was prepared as in Example 15 above with the addition of 8 parts by weight of fumaric acid. It was observed that composition 16 (Table 2b) has a gßl time of 60 seconds at 85 ° C and an RT stability of 30 days. The stability of the composition at 40 ° C was less than 9 days. 17) The epoxy resin composition 17 was prepared by mixing 100 parts by weight of Epikote 828 with 33 parts by weight of pentaerythritol tetrakis tris (β-mercaptopropionate) and adding 12 parts by weight of AJICURE PN-23 to this mixture. The components were thoroughly mixed and degassed to obtain the control composition of epoxy resin (Table 2a). Composition 17 (Table 2b) was observed to have a gel time of 35 seconds at 85 ° C and an RT stability of 4-7 days. The stability of the composition at 40 ° C was 2-4 days. 18) The composition 18 (Table 2a) was prepared as in Example 17 above with the addition of 4.64 parts by weight of fumaric acid. It was observed that the composition 18 (Table 2b) has a get time of 60 seconds at 85 ° C and a stability at room temperature of more than 30 days. The stability of the composition at 40 ° C was 7 days.

Comparative Example 19 19) Composition 19 (Table 2a) was prepared by mixing 100 parts by weight of Epikote 828 with 50 parts by weight of pentaerythritol tetrakis tris (β-mercaptopropionate) and 20 parts by weight of AJICURE PN-23, and with the addition of 4.0 parts by weight of barbituric acid. The composition 19 (Tabfa 2b) was observed to have a gel time of 90 seconds at 85 ° C and an RT stability of more than 17 days. The stability of the composition at 40 ° C was more than 17 days.

Example 20 - Control for Example 21. 20) The epoxy resin composition 20 was prepared by mixing 100 parts by weight of Epikote 828 with 50 parts by weight of pentaerythritol tetrakis tris (β-mercaptopropionate) and adding to this mixture 8 parts by weight of AJICURE PN-H. The components were mixed thoroughly and degassed to obtain the epoxy resin control composition (Table 2a). Composition 20 (Table 2b) was observed to have a gel time of 30 seconds at 85 ° C and an RT stability of 8 days. The stability of the composition at 40 ° C was 2-4 days.

Example 21. 21) Composition 21 (Table 2a) was prepared as in Example 20 above, but with the addition of 3.62 parts by weight of barbituric acid. It was observed that composition 21 (Table 2b) has a gel time of 70 seconds at 85 ° C and an RT stability of more than 30 days. The stability of the composition at 40 ° C was 8 days.

Example 22 - Control for Example 23. 22) The epoxy resin composition 22 was prepared by mixing 100 parts by weight of Epikote 828 with 50 parts by weight of pentaerythritol tetrakis tris (β-mercaptopropionate) and adding 30 parts by weight to this mixture. of AJICURE PN-H. The components were mixed thoroughly and degassed to obtain the epoxy resin control composition 22 (Table 2a). Composition 22 (Table 2b) had a gel time of 20 seconds at 85 ° C and an RT stability of 3-4 days. The stability of the composition at 40 ° C was less than 16 hours.

Example 23. 23) The composition 23 (Table 2a) was prepared as in Example 22 above, but with the addition of 8 parts by weight of 3,4-dihydroxy-cinnamic acid. It was observed that composition 23 (Table 2b) has a gßl time of 120 seconds at 85 ° C and an RT stability of 11 days. The stability of the composition at 40 ° C was 6 days.

Example 24 - Control for Example 25. 24) The epoxy resin composition 24 (Table 2a) was prepared by mixing 100 parts by weight of Epikote 828 with 50 parts by weight trimethyltolpropane tris (β-mercaptopropionate) and adding to this mixture. parts by weight of AJICURE PN-23. The components were mixed thoroughly and degassed to obtain the control composition of epoxy resin. Composition 24 (Table 2b) had a gef time of 25 seconds at 85 ° C and an RT stability of 3-16 hours. The stability of the composition at 40 ° C was less than 16 hours.

Example 25 ) The composition 25 (Table 2a) was prepared as in Example 24 above, but with the addition of 8 parts by weight of Trolox. It was observed that composition 25 (Table 2b) has a gel time of 120 seconds at 85 ° C and an RT stability of 21 days. The stability of the composition at 40 ° C was 3-4 days.

Example 26 - Control for Examples 27 to 40. 26) The epoxy resin composition 26 (Table 3a) was prepared by mixing 100 parts by weight of Epikote 828 with 50 parts by weight of pentaerythritol tetrakis (β-mercaptopropionate) and adding to this mix 20 parts by weight of AJICURE PN-23. The components were thoroughly mixed and degassed to obtain the epoxy resin control composition. It was observed that the composition 26 (Table 3b) has a gel time of 20 seconds at 85 ° C and a stability RT of 3-16 hours.

Examples 27 to 40. 27) Composition 27 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of 3,4,5-trimethoxy benzoic acid. It was observed that composition 27 (Table 3b) has a gel time of 200 seconds at 85 ° C and an RT stability of 25 days. 28) The composition 28 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of fumaric acid. It was observed that composition 28 (Table 3b) has a gel time of 120 seconds at 85 ° C and an RT stability of 48 days. 29) Composition 29 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of 2,3-dicyanohydroquinone. It was observed that composition 29 (Table 3b) has a gel time of 150 seconds at 85 ° C and an RT stability of 11 days. 30) The composition 30 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of hexachlorophene. It was observed that the composition 30 (Table 3b) has a gel time of 30 seconds at 85 ° C and an RT stability of 9 days. 31) The composition 31 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of 2,2'-dithiosalicylic acid. It was observed that composition 31 (Table 3b) has a gef time of 25-30 seconds at 85 ° C and an RT stability of 11 days. 32) The composition 32 (Table 3a) was prepared as in the Example 26 above, but with the addition of 8 parts by weight of 3,4-dihydrocinnamic acid. It was observed that composition 32 (Table 3b) has a gel time of 20 seconds at 85 ° C and RT stability of 11 days. 33) The composition 33 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of 3,4-dihydroxy benzoic acid, It was observed that the composition 33 (Table 3b) has a time of ge! of 60-90 seconds at 85 ° C and RT stability of 13 days. 34) The composition 34 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of 4,5,7-tri- hydroxyflavanone acid. It was observed that the composition 34 (Table 3b) has a gel time of 35 seconds at 85 ° C and a stability RT of 1.5 days. 35) The composition 35 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of 3,5-dinitrosaticilic acid. It was observed that composition 35 (Table 3b) has a gel time of 60-90 seconds at 85 ° C and an RT stability of 4 days. 36) The composition 36 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of 3,4,5-trihydroxybenzoic acid. It was observed that composition 36 (Table 3b) has a gel time of 120 seconds at 85 ° C and an RT stability greater than 12 days. 37) Composition 37 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of barbituric acid. It was observed that composition 37 (Table 3b) has a gel time of 90 seconds at 85 ° C and an RT stability greater than 12 days. 38) The composition 38 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of parabanic acid. It was observed that composition 38 (Table 3b) has a gef time of 90 seconds at 85 ° C and RT stability greater than 12 days. 39) Composition 39 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of tetrahydroxy-p-banzoquinone. It was observed that composition 39 (Table 3b) has a gßl time of 60 seconds at 85 ° C and RT stability greater than 19 days. 40) The composition 40 (Table 3a) was prepared as in Example 26 above, but with the addition of 8 parts by weight of 4-nitroguaiacol. It was observed that the composition 40 (Table 3b) has a gel time of 60-80 seconds at 85 ° C and a stability RT of 6-7 days.

Example 41 - Control for Example 42. 41) The epoxy resin composition 41 (Table 4a) was prepared by mixing 100 parts by weight of RE-310S epoxy resin with 50 parts by weight of pentaerythritol tetrakis (β-mercaptopropionate) and adding to Mix 5 parts by weight of AJICURE PN-23. The components were thoroughly mixed and degassed to obtain the control composition 41 of epoxy resin. It was observed that composition 41 (Table 4b) has a gßl time of 37 seconds at 85 ° C and an RT stability of less than 24 hours.

Example 42. 42) The composition 42 (Table 4a) was prepared as in Example 41 above, but with the addition of 2 parts by weight of barbituric acid. It was observed that the composition 42 (Table 4b) has a gel time of 80 seconds at 85 ° C and an RT stability greater than 35 days. The stability of the composition at 40 ° C was 25 days.

Example 43 - Control for Example 44. 43) The epoxy resin composition 43 was prepared by mixing 100 parts by weight of RE-310S epoxy resin with 50 parts by weight of pentaerythritol tetrakis (β-mercaptopropionate) and adding 5 parts to this mixture. in weight of AJICURE PN-H. The components were thoroughly mixed and degassed to obtain the control composition 43 of epoxy resin. It was observed that composition 43 (Table 4b) has a gel time of 55 seconds at 85 ° C and an RT stability of 4 days. The stability of the composition at 40 ° C was less than 24 hours.

Example 44. 44) Composition 44 (Table 4a) was prepared as in Example 43 above, but with the addition of 2 parts by weight of barbituric acid. It was observed that composition 44 (Table 4b) has a gel time of 105 seconds at 85 ° C and an RT stability greater than 35 days. The stability of the composition at 40 ° C was 25 days.

Example 45 - Control for Examples 46 and 47. 45) The epoxy resin composition 45 (Table 4a) was prepared by mixing 100 parts by weight of epoxy resin RE-310S with 100 parts by weight of trimethylolpropane tris (β-mercaptopropionate) and adding 20 parts by weight of AJICURE PN-H to this mixture. The components were thoroughly mixed and degassed to obtain the epoxy resin control composition. It was observed that the composition 45 (Table 4b) has a gel time of 42 seconds at 85 ° C and an RT stability of 5 days. The stability of the composition at 40 ° C was 2 days.

Examples 46 and 47. 46) The composition 46 (Table 4a) was prepared as in Example 45 above, but with the addition of 8 parts by weight of fumaric acid. It was observed that the composition 46 (Table 4b) has a gel time of 54 seconds at 85 ° C and an RT stability greater than 30 days. The stability of the composition at 40 ° C was 5 days. 47) The composition 47 (Table 4a) was prepared as in Example 45 above, but with the addition of 8 parts by weight of barbituric acid. It was observed that composition 47 (Table 4b) has a gal time of 150 seconds at 85 ° C and an RT stability greater than 30 days. The stability of the composition at 40 ° C was 6 days.

Example 48 - Control for Eiempfo 49. 48) The epoxy resin composition 48 (Table 4a) was prepared by mixing 100 parts by weight of RE-310S epoxy resin with 50 parts by weight of trimethylolpropane tris (β-mercaptopropionate) and adding to This mixture 50 parts by weight of AJICURE PN-23. The components were thoroughly mixed and degassed to obtain the control composition of epoxy resin. It was observed that composition 48 (Table 4b) has a gel time of 58 seconds at 85 ° C and an RT stability of 5-6 days. The stability of the composition at 40 ° C was less than 24 hours.

Example 49. 49) The composition 49 (Table 4a) was prepared as in Example 48 above, but with the addition of 2 parts by weight of barbituric acid. It was observed that composition 49 (Table 4b) has a gel time of greater than 300 seconds at 85 ° C and a stability of RT greater than 30 days. The stability of the composition at 40 ° C was greater than 25 days. These forty-nine compositions, along with certain physical properties, are tabulated in Tables 1-4 attached. As can be seen from the previous Examples, the stabilizing effect is achieved even with the more reactive latent hardener AJICURE PN-23. The AJICURE PN-23 is more reactive than the AJICURE PN-H.

II. Physical Properties We review each composition in its gelling and stability times ('life in ofla') at room temperature ("RT"). A control experiment not containing solid organic acid was prepared simultaneously and using materials from the same batches of potiol resin / hardener and was used to compare gel time and stability with the composition containing organic acid base. Eff gel time at 85 ° C was determined by applying a spot of adhesive composition on a glass slide maintained at a temperature of 85 ° C. The slide was then placed on the surface of a thermostatically controlled hot plate maintained at 85 ° C, from which time the gelling time was recorded. Each composition was then stored at both ambient temperatures and 40 ° C. The time required for the initial viscosity of each composition to reach the gel point (gelled) was recorded. The viscosity was used to indicate gelling (a point beyond which the composition is unusable). In Examples RT is 20-25 ° C. In the following Tables the stability of each composition is measured as "pot life".

TABLE 1 TABLE 1b TABLE 2a TABLE 2b TABLE 3a TAB 3b TABLE 3A (continued) TABLE 3b (continued) 10 TABLE 4a TABLE 4b Tables 5a and 5b below expose the shear strengths for compositions in pot lives and gel times., 6, 24, 25, 26, 19, 27, 30, and 39 above respectively. We determine the adhesive bond strength by tensioning a simple adhesive overlap joint with the application of a parallel tension force to the joining area and further away from the lap cut according to the procedure detailed in the recognized ASTM D1002 test method. internationally. Five tests were conducted for each composition and the result presented in Table 5b is the average of the five results. The compositions 5, 24 and 26 represent the control compositions. Compositions 6, 25, 19, 27, 30 and 39 are compositions of the present invention. As seen in Table 5b the compositions of the invention form unions of comparable shear strength compared to the bonds formed by the control compositions. Their gel times remain relatively low, while their pot lives at 25 ° C-40 ° C show a substantial increase. t? l Tables 6a and 6b below disclose a composition containing a combination of solid organic acids, Trofox and tetrahydroxy benzoquireone. We prepared a control composition (composition 1) (Table 6a) containing 100 parts by weight of Epikote 82ß, 75 parts by weight of trimethylolpropane tris (β-mercaptopropium αto), and 25 parts by weight of Ajicure PN-23. The composition was tested as before for cut resistance, gef time, life in RT at RT and pot life at 40 ° C. Composition 2 (Table 6a) was prepared as composition 1, but adding 2 parts by weight of Trolox, before the addition of the hardener. Composition 3 (Table 6a) was prepared as composition 1, but adding 1 part by weight of tetrahydroxy benzoquinone, before the addition of the hardener. Cut resistance, gef times, and pot life at RT and 40 ° C, for compositions 2 and 3 are also shown ßrt fa Table 6b. Composition 4 (Table 6a) was prepared as composition 1, but with both 2 parts by weight of Trolox and one part by weight of hydroxy benzoquinone, before the addition of the hardener. The cut resistance, gel times, and life in oila at RT and 40 ° C for composition 4 (Tabfa ßa) show an increase in pot life at 40 ° C compared to control compositions 2 and 3 each containing only one of the solid organic acids.

TABLE 6a TABLE 6b III. Effect of particle size of solid organic acid. Tables 7a and 7b refer to a control composition, composition 6 and compositions 6 (a) to 6 (d) of the invention. We prepare and test these compositions as described below: The control composition was prepared as described in Example 5 above. Composition 6 is a composition prepared as described in example 6 above (which has added fumaric acid). The added fumaric acid was supplied (by Aldrich Chemical Co.), ie, without milling. An analysis of the particle size of fumaric acid as supplied showed that the solid has a wide range of particle sizes from 0.4 to 400 microns in size. The average particle size was determined to be 108.9 microns. The compositions 6 (a) to 6 (d) were prepared as in Example 6, (each composition 6 (a) to 6 (d) contains fumaric acid which was milled and passed through a series of sieves to obtain milled fumaric acid having a particle size of 53-75 microns.Frumed fumaric acid was used in compositions 6 (a) to 6 (d) inclusive in amounts of 1, 2, 8 and 20 parts by weight of the composition Gel times and shear strengths were determined as described above. You can see that very low concentrations of finely ground fumaric acid (compositions 6 (a), 6 (b) and 6 (c) in particular) can achieve gel times, shear strengths and stability comparable to those compositions containing higher levels of Unmilled fumaric acid (composition 6) The composition 6 (d) in particular illustrates that in order to obtain the best combination of gel time, stability and binding strengths the particle size should be considered. stabilizer men or they can improve their effect without altering the amount of the solid acid used by reducing the particle size of the solid organic acid by grinding or in any other way.

TAB 7a without mofer refers to material used as a supplier redbe def. 10 Ú 7b fifteen Tables 8a and 8 (b) illustrate how controlling the particle size of barbituric acid affects both stability (pot life) and gel time.

Preparation of compositions: We prepare and test these compositions as described below: The compositions in Table Sa were prepared by mixing together 100 parts by weight of each of the poxy resins EP 828 and EPON 862 and heating the mixture at 60 ° C. To this mixture was added 25 parts by weight of DEN 438 epoxy resin preheated to 60 ° C to lower its viscosity. The resins were mixed and 40 parts by weight of trimethyol propane tris (b-mercaptopropionate) and 125 parts by weight of pentaerythritol tetrakis (b-ercaptOpropionate) were added and mixed. The mixture was allowed to cool to room temperature before adding the specified amount of barbituric acid. Barbituric acid was not added to one of these compositions which was used as a control. The barbituric acid was prepared by passing it through a triple roller mill as a 10% dispersion in epoxy resin EP 828. This step reduced the particle size of the barbituric acid. Six compositions 1 (a) to 3 (b), divided into 3 pairs, each pair with roller-ground acid dispersions with different average particle sizes (5.54, 6.97 and 7.84 microns) were added to either 0.9 or 1.8 parts in weight level. The latent hardener was then added at a 62.3 parts level and mixed into the mixture. The term "parts by weight" refers to parts by weight of the total composition.

Results: Table 8a illustrates the results of the tested compositions. Each of the compositions showed excellent storage stability as evidenced by pot life results. Stability is achieved with relatively small amounts of the acid. The results compare favorably with those achieved with the addition of fumaric acid (Table 7). Minor amounts of barbituric acid of a smaller particle size were observed that give similar results with larger amounts of barbituric acid of larger particle size. All the compositions of the invention showed much improved pot lives compared to the control compositions. The results are not adversely affected by the use of two potitols and three epoxy resins. The gel times are very favorable also in comparison with the control composition.

TABLE 8a TABLE 8b Tables 9a and 9b further illustrate how controlling the particle size of barbituric acid affects both stability (pot life) and gel time.

Preparation of compositions: We prepare and test these compositions as described below; Compositions 2 (a) and 2 (b) were prepared as in Example 7 except that the unmilled barbituric acid was replaced with a sample of barbituric acid as a 10% dispersion in EP 828 epoxy resin to reduce particle size of the acid (as described above). It was determined that the acid has an average particle size of 5.54 microns with confidence limits greater than 95% that all particles are less than 13.4 microns. Compositions 3 (a) and 3 (b) were also prepared as in Example 7 except for the use of ground acid with an average particle size of 14.0 microns with confidence limits greater than 95% that all particles are lower of 34.9 microns. The control composition of Example 5 and the composition det Example 7 are included in Tables 9a and 9b for comparative purposes. Ef average particle size of the unmilled acid was determined to be 45 μm with a broad particle distribution of up to 200 μm.

Results: Tabta 9a shows that by controlling the particle size of the acid used as a stabilizer, relatively rapid gel times can be obtained without compromising the life of the system. All compositions show a significant improvement over the control composition. Barbituric acid with particle size reduced in substantially smaller amounts achieves a very significant stabilizing effect compared to the larger particle size.

TABLE 9a TABLE 9b IV. Experimental data relative to compositions containing both, an olitiol and a component that confers thixotropy. Tables 10a and 10b further demonstrate the effect of particle size on the pot life of two compositions and the shear strength of bonds formed using these compositions. Table 10c gives the rheological properties of the compositions. The information is graphed in Figures 4A and 4B.

Preparation: We prepare and test these compositions as described below: Composition 1 (Table 10a / b) was prepared by mixing 100 parts of epoxy resin EP 828 and 75 parts of trimethylol propane tris (b-mercaptopropionate). This was followed by the addition and dispersion of 0.50 parts by weight of barbituric acid. Then 15.6 parts by weight of the thixotropic component AEROSIL 202 was added to the composition. Finally, 25 parts by weight of the latent hardener was added. Composition 2 was prepared by mixing 100 parts of epoxy resin EP 828 and 94.5 parts of trimethylol propane tris (b-mercaptopropionate). The temperature of the mixture was raised to 60 ° C before the addition of 30.26 parts ert weight of epoxy resin novolak DEN 438 which had previously been preheated to 60 ° C to lower its viscosity. When cooling to room temperature, 0.635 parts by weight of barbituric acid followed by 20.57 parts by weight of the component that confers thixotropy AEROSIL 202 were mixed in the mixture. Finally, 33.26 parts by weight of the latent hardener was added to the composition. The barbituric acid used in each case had an average particle size of 14.0 μm with 95% confidence that all the acid had a particle size less than 34.9 μm. The shear strength was measured by the method described above.

Results: Compositions 1 and 2, both, showed very good stability and both form unions that have good cut resistance. The yield point and viscosity of the 2 compositions remained at desirable levels throughout the duration of the tests.

The values given in Table 10c are plotted in Figures 4A and 4B. A control composition was prepared without adding barbituric acid. The comparative information with the control composition is not given since the control had a viscosity that rendered it unusable after 16 hours and therefore was not useful for inclusion in Tables 10a-c or Figures 4A or 4B.

TABLE 10a TABLE 10b TABLE 10c V- RHEOLOGICAL STABILITY The reoigy of the assorted epoxy resin composition should be adjusted appropriately to provide the desired point profile. In addition, the quantity supplied must also be adjusted according to the design parameters of the electronic component. Such adjustments are left to persons of ordinary skill in the art, and of course, they depend on the specifications set by the end user of the composition. In an on-chip application the compositions of the invention comprise a component which confers thixotropy can be advantageously deposited in a 3-dimensional manner when used with the template provided by European Patent No. 770,006, the description of which is expressly incorporated herein by reference. the present by reference. In this way, not only two-dimensional deposits are produced according to the location and density of holes in the template, but also their heights can vary over the pattern area. This is particularly attractive when assembling electronic components because often times the components have different heights held at a distance and the electrodes can be separated from each other by different distances. The importance of the shape of the adhesive point can be seen with reference to Figures 1 and 2. In a typical commercial application of such an epoxy-based adhesive composition for surface mounting the chipo on ßt pcb, the point should be sufficiently high with reference to the surface of the substrate or chip to make contact with the chip to be mounted on the surface, but not so high that it would fall to form a dimension that can block the welding zones. The shape of the stitch can be adjusted by the addition of builders of suitable structures, such as the thixotropy conferring components discussed herein. An epoxy composition that can be supplied over the entire period of its shelf life to give reliable and reproducible points forms is achieved by using a composition that maintains its yielding point with time. For example, the most commercially available epoxy-based compositions should be stored according to the manufacturer's recommendations or below 5 ° C and used within 6-9 months of manufacture. In the event that such conditions of storage and use are not met, you may encounter assortment problems with conventional adhesives whose rheological properties may have changed as a result of not complying with those recommendations. As such, an assorted point of adhesive may tend to disperse in shape and therefore, not meet the desired point profile specified for the particular commercial application. Such adhesivot therefore has not maintained its yielding point over time. The compositions of this invention are less prone to undergo cedential point decreases or viscosity increases in the probable case that the end user does not use the compositions in accordance with the conditions of storage and use recommended by the manufacturer. As the shape of the point loses its height (which has been chosen to join the chip, at a particular maintained height), its base is expanded to block the welding zones. The blocking of the welding zone by the adhesive could cause the electrical discontinuity in the assembly device thus formed, so that a failure is created and, very important, the interruption in the manufacturing cycle.

SAW. PREPARATION OF COMPOSITIONS BASED ON EPQXI. We prepare compositions according to the second aspect of this invention, and also prepare known compositions of epoxy resin to compare their observed rheological properties, such as yield point and viscosity over time. Most of the information reported is taken from observations at room temperature, although some of the information is taken from conditions with accelerated aging (at a temperature of about 40 ° C) to provide a guide to how an adhesive composition can go in the market. More specifically, we prepare epoxy resin compositions with the following components in the amounts indicated below in Table 11.

TABLE 1 1 These compositions were prepared by mixing the epoxy component, the thixotropy-conferring component and the solid organic acid in a vessel under ambient temperature conditions for a period of time of about 2 hours. Then, the latent hardener component was added. Vacuum was applied to the mixing vessel at appropriate times during the preparation of the sample composition in order to deaerate the compositions. Mixing was allowed to continue, under intermittent vacuum, under ambient temperature conditions, for a period of time of about 3 hours. We initially measured fiow curves for compositions Nos. 101 and 102 using a Haake cone and a plate viscometer (Model No. Haake PK 100, Karlsruhe, Germany), along with curve fitting software (Rotovisco RV20, vßr.ROT 2.4 .3.) Provided with the viscometer, to determine the cedential point and viscosity of the compositions. The shear stress in the compositions was measured as a function of the cutoff rate and the information was adjusted to the mathematical mode of Casson using the curve fitting software from which the yield point and the viscosity are determined. The Haake PK 100 system is fixed using the anterior head and cone, the composition is loaded and the excess material is removed. The composition is allowed to equilibrate at the test temperature of 25 degrees C for 5 minutes and then the composition is reconditioned running a tension / time ramp for 5 minutes at 0.5 S "1. Following immediately to the conditioning period a curve of flow rate of tension / cut of 0.3 s "1 to 40 s_ for 6 minutes collecting 40 points of information. The information is stored then. A plot of shear stress (Pa) versus shear rate (s "1) is made on the log scale before carrying out a regression using the Casson model on the range of 0.4 to 30.0 s * 1. The regression should be simulated to the region before the start of the cut fracture (if present) This analysis will give the Casson yield value (Pa) and the Casson infinite cut viscosity (Pa.s). be 0.98 or greater, then filter the compositions Nos. 101 and 102, and again measured flow curves.The dropping point is observed in an ordinary way that falls after filtering.Filtration is important in the repair of adhesives for chip bonding. , or for that matter of any adhesive to be supplied from a narrow meter tip, due to the possibility of blocking the assortment path with, for example, harmful material.We then store the compositions at room temperature and measure their flow curves in Weekly intervals for a period of time of approximately 18 weeks. This information was recorded in Table 12 below.

TABLE 12 However, because compositions Nos. 101 and 102 exhibited different initial values of yield point (446.3 and 889.2 Pa, respectively), we prepared compositions Nos. 103, 104, and 105 for further comparative purposes, with composition No. 105 containing a higher level of the silica component, that is, 28.5 parts.

Table 13 Composition No. 105 (which has an increased level of silica) exhibited an initial cedßntβ point of 855.5 Pa, which is comparable to that initially exhibited by fa composition No. 104. We then filter the compositions, measure their flow curves, and store the compositions at room temperature. We measure your flow curves at weekly intervals over a period of approximately 70 days. These results are presented later in Table 14, and can be more fully appreciated with reference to Figure 5.

TABLE 14 The yield points for compositions Nos. 103 and 105 (each of which are free of the solid organic acid component) show a marked decline at room temperature over time. (See figure 5). Composition No. 104 (with the solid organic acid component), on the other hand, shows a yield point that remains at the same level substantially over time. (See figure 5). Composition No. 105 shows the decrease in yield point more clearly than composition No. 103, since the yield point of composition No. 105 was initially established at a level comparable to that of composition No. 104 under the silica additional added as a component that confers thixotropy. For certain high-speed assortment applications, bonding adhesives must have a yield point in the range of approximately 150-450 Pa (see Table 15 below, compositions Nos. 106 and 107). With that application in mind, two additional compositions were prepared with their components (and amounts) and their rheological properties given below in Tables 15 and 16, respectively.

TABLE 15 TABLE 16 In Table 17, two compositions are shown, one of which contains as a component of solid organic acid fumaric acid (composition No. 108) and the other (composition No. 109) does not contain such solid organic acid is presented for comparative purposes to show the lack of maintenance of the yielding point over time. (See more adejantß Table 18).

TABLE 17 83 TABLE 18 Vile. PHYSICAL PROPERTIES. A. Accelerated Aging Information. We condition the composition No. 106 at a temperature of about 40 ° C to determine the effect of a temperature increase over time. The results are presented later in Table 19.

TABLE 19 From the results presented in this Table, it is seen that the compositions according to this invention work well with time, even in high temperature conditions, such as may be experienced when the end user does not follow the recommended conditions of use and storage. by the manufacturer. 8. Resistance to Cutting The adhesive composition (composition No. 106) was supplied on return cuts which are constructed of mild steel blown with grit and cured at a temperature of about 150 ° C for a period of about 30 minutes. The return cuts with the cured adhesive between an overlapping portion thereof were then maintained at room temperature for a period of about 24 hours. The adhesive bond strength was determined by tensioning a simple adhesive overlap joint with the application of a tension force parallel to the bonding area and the major axis of the return cuts according to the procedure detailed in the recognized ASTM D1002 test method. internationally. Five test specimens were evaluated for composition No. 106 and the results obtained as an average of the five observations show an af adhesive adhesive strength of 24.89 N / mm2. Regardless of the detailed description of the invention given above, the true spirit and scope of the invention is measured by the claims.

Claims (7)

1. CLAIMS 1. An epoxy resin composition comprising: (a) An epoxy compound having two or more epoxy groups per molecule, (b) A polythiol compound having two or more thiol groups per molecule, (c) A latent hardener , and (d) At least one solid organic acid that is substantially insolubles in a mixture of (a), (b) and (c) above, at room temperature.
2. 2. An epoxy resin composition comprising: (a) An epoxy compound having two or more epoxy groups per molecule, (b) A polythio compound; having two or more thiol groups per molecule, (c) A latent ßndurzcedor, and (d) At least one solid organic acid selected from the group consisting of d: aliphatic, cycloaliphatic and aromatic carboxylic acids and derivatives of cough, atypical quinones , cycloaliphatics and aromatics and derivatives thereof, phenols and derivatives thereof and aiiphatic, cycloaliphatic and enolizable aromatic compounds and derivatives thereof.
3. 3. An epoxy resin composition comprising: (a) An epoxy compound having two or more epoxy groups per molecule, (b) A polythiol compound having two or more thiol groups per molecule, (c) A latent hardener, and (d) At least one solid organic acid having a pKa of less than or equal to about 12.0, desirably less than or equal to about 10, more suitably less than or equal to about 9.0, and desirably less than or equal to approximately 7.5.
4. 4. An epoxy resin according to claim 2 or claim 3 wherein the acid (d) is unsolubie substantially in a mixture of (a), (b) and (c), at room temperature.
5. 5. An epoxy resin composition as claimed in any preceding claim wherein the organic acid is selected from: (j) carboxylic acids of the general Formula I: R1CO2H I wherein: Rt is trans-CH = CHCO2H, -CH * CHCO2R [R is CH3], -CH2C (OR ') (CO2R ") - CHaCOaR"', [R 'is H, C 1 -C 10 alkyl, Ar], R "is H, C 1 -C 10 alkyl, Ar ], [R "'is H, C1-C10 alkyl, Ar], Cn-C18 alkyl, - (CH2) nCO2H [n is 1-9], - (CH R) nCO2H [R is H, OH, n is 1 or 2], -CH (OR ') R "[R' is H, alkyl, R "= d-Cio, Ph], -CH = CH-Ar, (ii) benzoic acids of the general Formula 11 wherein: Ri is H, alkyl, haloalkyl such as CX3 [X is F, Cl, Br, I], alkenyl, OH, OR [R is alkyl, Ph, Bn, Ar], -S-S-Ar-CO2H, -S-S-Ar; -SR [R is H, alkyl, haloalkyl, Ph, Bn, Ar], Ph, Bn, Ar, CO2R [R is H, alkyl, Ph, Bn, Ar], CO.R [R is H, alkyl, Ph , Bn, Ar], NO2, R2 is H, alkyl, haloalkyl such as CX3 [X is F, Cl, Br, I], alkenyl, Ph, Bn, Ar, OH, OR, [R is alkyl, Ph, Bn , Ar], -CH2Ar, NO2, CO. R [R is C? -C10 alkyl, Ph, Bn, Ar], CHO, CO2R [R is H, alkyl, haloalkyl, Ph, Bn, Ar], or R3 is H, alkyl, haloatquyl such as CX3 [X is F, Cf, Br, f], alkenyl, OH, OR [R is alkyl, Ph, Bn, Ar] Ph, Bn, Ar, alkyl, CHO, CO. R [R is alkyl, Ph, Bn, Ar], CO2R [R is H, alkyl, Ph, Bn, Ar] NO2; R4 is H, alkyl, hafoacyl such as CX3 [X is F, Cl, Br, I], alkenite, OH, OR [R is alkyl, Ph, Bn, Ar] NO2, CO.RfR is alkyl, Ph, Bn, Ar], CHO, CO2R [R is H, alkyl, Ph, Bn, Ar], Ph, Bn, Ar; Rs is H, alkyl, haloalkyl such as CX3 [X is F, Cl, Br, I], alkenyl, OH, ORfR is alkyl, Ph, Bn, Ar], Ph, Bn, Ar, CHO, CO.R [R is alkyl, Ph, Bn, Ar], CO2R [R is H, alkyl, Ph, Bn, Ar], N02, or (iii) quinones of the general Formula lli: wherein: Ri, 2, R3, and R4 are independently H, alkyl, haloalkyl, atkenyl, ORfR is H, alkyl, Ar, Ph, Bn] CN, Ph, Ar. (iv) phenols of the general Formula IV: wherein: R is H, OH; R 1 is H, alkyl, haloatchyl such as CX 3 [X is F, Cl, Br, I], alkenyl, Cl, F, Br, I, CN, OH, OR [R is alkyl, Ph, Bn, Ar], NO2, CO.RfR is alkyl, Ph, Bn, Ar], CHO, CO2R [R is H, alkyl, Ph, Bn, Ar], PhOH, R2 is H, alkyl, haloalkyl, alkenyl, OH, OR ,. { R is alkyl, Ph, Bn, Ar], Ph, Bn, -CH2Ar, CN, F, Cl, Br, I, R3 is H, alkyl, haloalkyl such as CX3 [X is F, Ct, Br, l], alkenyl,NO2, CO.R [R is alkyl, Ph, Bn, Ar] CHO, CO2R [R is alkyl, Ph, Bn, Ar], OH, OR [R is alkyl, Ph, Bn, Ar], Ar, Bn, Ph, C (R) 2PhOH fR is Me or H], C (R) aAr [R is Me or H] or: wherein: Rβ, and R7 are independently H, alkyl, haloalkyl, alkenyl, OH, OR fR is alkyl, Ar, Ph, Bn]; R4 is H, alkyl, haloalkyl, alkenyl, OH, ORfR is alkyl, Ph, Bn, Ar], F, Cl, Br, I, CN, Ph, Bn, -CH2Ar; Rs is H, alkyl, haloalkyl such as CX3fX is F, Cl, Br, I], alkenyl, F, Cl, Br, I, CN, OH, ORfR is alkyl, Ph, Bn, Ar], NO2, CO.RfR is alkyl, Ph, Bn, Ar], CHO, CO2RfR is H, alkyl, Ph, Bn, Ar], PhOH, provided that a compound of the general Formula V having at least one phenolic group present is selected, or (v) materials enolizables of the General Formula IV: wherein: Ri or R2 are NR'CO.NR "R" 'fR' is H, alkyl, Ph, Ar, R "is H, alkyl, Ph, Ar, R" 'is H, alkyl, Ph, Ar] , ORfR is H, alkyl, Ph, Ar] X is (CH2) n, C (R) 2 [R is alkyl, Ph, Ar, CN], O, S, NRfR is H, alkyl, Ph, Ar], n is 0-10, or (vi) enolizable materials of the general Formula VI: where: (a) X1 = X2 = NH, R = H, R? = O, n = 1; or (b) X1 = X2 = NH, R? = O, n is zero so that the cyclic structure has a ring of five members; or (c) X ^ Xa'O, R = H, R? = (CH3) 2, n = 1; or (d) X ^ X ^ 0, R = Ph, R? = (CH3) 2, n = 1.
6. 6. An epoxy resin composition as claimed in any preceding claim wherein the solid organic acid is selected from the group consisting of: 4-nitroguayacol, 3,4,5-trimethoxy benzoic acid, hexachlorophene, 3,5-dinitrosalicylic acid , 4,5,7-trihydroxyflavanone, 2,2-dithiosalicylic acid, phloroglucinol, fumaric acid, 3,4-dihydroxybenzoic acid, 3,4,5-trihydroxy benzoic acid, β-hydroxy-2,5,7 acid, 8-tetramethyl chroman-2 carboxylic acid, pamico acid, ascorbic acid, salicylic acid, citric acid, 3,4-dihydroxy cinnamic acid, 2,3-dicyan hydroquinone, barbituric acid, tetrahydroxy-p-benzoquinone, parabanic acid, phenyl boronic acid , 5-phenyl d-Meldrum acid and Meldrum acid. An epoxy resin composition as claimed in any preceding claim wherein the epoxy compound is selected from any polymeric epoxide which has an average of 2 or more epoxide groups per molecule, including polyglycidyl ethers of bisphenol A, bisphenol F, bisphenol AD, catechol, resorcinol, or epoxy compounds obtained by reacting polyhydric alcohols such as butanediol or polyethylene glycol with epichlorohydrin, epoxidized olefin resins, novolac phenolic resins, cresol novolac resins, cycloaliphatic epoxy resins, diester glycidyl ether esters, polyglycidium esters , modified urethane esters and paiiepoxy compounds based on aromatic amines and epichlorohydrin. 8. An epoxy resin composition as claimed in any preceding claim wherein the polythioth compound is selected from any mercapto compound having two or more thiol groups per molecule such as trimethyl propane tris (β-mercaptopropionate), trimethylol propane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate), pentaerythritol tetrakis (β-mercaptopropionate), dipentaerythritol poly (β-mercaptopropionate), ethylene glycol bis (β-mercaptopropionate), and alkyl polyols such as butane-1,4- dithiol, hexane-1,6-dithiophy, and polythiol aromatics such as px? lenditiot and 1, 3,5-tris (m? captomethyl) benzene. 9. An epoxy resin composition as claimed in any preceding claim wherein the ratio of the epoxy compound to the polythiot compound in the composition is such that the ratio of epoxy equivalents to thioi equivalents is from about 0.5: 1 to about 1.5: 1. , more suitably from about 0.75: 1 to about 1.3: 1. An epoxy resin composition according to any preceding claim wherein the latent hardener (c) is present in amounts of from about 1 to about 60 parts by weight per 100 parts by weight of the epoxy compound (a), suitably from about 1 to about 45 parts, more suitably from about 1 to about 30, desirably from about 10 to about 20, parts by weight. 11. An epoxy resin composition according to any preceding claim wherein the solid organic acid is present in an amount of from about 0.1 to about 80 parts by weight per 100 parts by weight of the latent hardener (c), suitably from about 0.5 to about about 45 parts by weight, desirably from about 1 to about 5 parts by weight. 12. An epoxy resin composition according to any preceding claim wherein the acid has an average particle size in the range of about 0.1 to about 500 microns, suitably about 5 to about 100 microns, and desirably about 10 to about 50 microns. 13. An epoxy resin composition according to any preceding claim comprising two or more solid organic acids. 14. An epoxy resin composition according to any preceding claim wherein the composition is a one-part adhesive composition. 15. An epoxy resin composition according to any preceding claim wherein the composition further comprises: (e) a component that confers thixotropy. 16. A curable epoxy resin composition on the one hand with improved rheological properties for use as an adhesive for mounting electronic components on a substrate, the composition of a part comprising the components of a composition according to any preceding claim. 17. An epoxy curable composition of a part capable of sealing under the filling between a semiconductor device including a semiconductor chip mounted on a carrier substrate and a circuit board to which said semiconductor device is electrically connected, said composition of a part comprising the components of a composition according to any preceding claim. 18. A composition according to claim 15 which has transfer point maintenance and viscosity maintenance over time. 19. A curable epoxy resin composition on the one hand with improved rheological properties, comprising: (•) An epoxy component comprising at least one epoxy compound, (ii) A latent hardener component, and (iii) A component that It confers thixotropy, and (iv) A component of solid organic acid. wherein the solid organic acid component improves the maintenance of the yield point and the maintenance of the viscosity of the composition over time. 20. A curable epoxy resin composition on the one hand with improved rheological properties suitable for use as an adhesive for assembling electronic components, comprising: (i) An epoxy component comprising at least one epoxy compound, (i) A component of latent hardener, (iii) A component that confers thixotropy, and (iv) A solid organic acid component, where the solid organic acid component improves the maintenance of the yield point and the maintenance of the viscosity of the composition over time. . 21. A curable epoxy resin composition on the one hand with improved rheological properties suitable for use as an adhesive for assembling electronic components, comprising: (i) Approximately 150 parts of an epoxy component comprising at least one epoxy compound, (ii) ) Approximately 42.36 parts of a latent hardener component, (iii) Approximately 19.26 parts of a component that confers dixotropy, and (iv) Approximately one part of a solid organic acid component. 22. A curable composition of epoxy resin on one side with improved rheological properties suitable for use as an adhesive for assembling electronic components, comprising: (i) Approximately 171.67 parts of an epoxy component comprising at least one epoxy compound, (ii) Approximately 42.36 parts of a latent hardener component, (ii) Approximately 19.26 parts of a dixotrope-conferring component, and (iv) Approximately a part of a solid organic acid component. 23. A curable epoxy resin composition on the one hand with improved rheological properties suitable for use as an adhesive for mounting electronic components, comprising: (a) about 100 parts of an epoxy component comprising at least one epoxy compound, (b) ) about 25 parts of a latent hardening component, (c) about 15.6 parts of a dixotropy-conferring component, (d) about 75 parts of a polythiol component, and (e) about 0.5 parts of a solid organic acid component. . 24. A curable composition of epoxy resin on the one hand with improved reogenic properties suitable for use as an adhesive for assembling electronic components, comprising: (a) about 130.26 parts of an epoxy component comprising at least one epoxy compound, (b) ) about 33.26 parts of a latent hardener component, (c) about 20.57 parts of a thixotropy-conferring component, (d) about 94.5 parts of a polythiol component, and (e) about 0.635 parts of a solid organic acid component . 25. A curable epoxy resin composition on the one hand with improved rheological properties suitable for use as an adhesive for assembling electronic components, comprising: (a) an epoxy component comprising at least one epoxy compound, (b) a component of latent hardener, and (c) a component that confers dixotropy, and (d) a solid organic acid component, wherein the composition has a yield point in the range of about 30-700 Pa, suitably about 150-450 Pa, desirably about 300-400 Pa, and a viscosity in the range of about 1 to 50 Pa.s, suitably about 1 to 25 Pa.s, desirably about 1 to 10 Pa.s, more desirably about 3-4 Pa.s, with each one of the guys being substantially maintained within the respective ranges with time. A process for preparing a curable epoxy resin composition on the one hand with improved reofhogenic properties, comprising the steps of: initially combining (i) an epoxy component comprising at least one epoxy component, (iii) a component that confers thixotropy, and (iv) a solid organic acid component, then combine (ii) a latent hardener component, and mix together the components (i), (ii), (iii) and (iv) for a sufficient time to form a Epoxy curable composition on the one hand with improved transfer point maintenance and viscosity maintenance. 27. A mounting structure for semiconductor devices, comprising: A semiconductor device comprising a semiconductor chip mounted on a carrier substrate; and a circuit board to which the semiconductor device is electrically connected, wherein the space between the carrier substrate of the circuit board and the semiconductor device is sealed with the cured product of a composition according to any of claims 1 to 25. 28. An electronic device comprising a semiconductor device and a circuit board to which said semiconductor device is electrically connected, assembled using an epoxy resin composition according to any of claims 1 to 25 for mounting the semiconductor device to the circuit board . 29. A method for using a composition according to any of claims 1 to 25, the method comprising the steps of: dispensing on an appropriate location on a carrier substrate a sufficient amount of the composition, placing on the location supporting the composition. composition an electronic component, equalizing the electronic component with the carrier substrate, and exposing the electronic component / carrier substrate assembly matched to favorable conditions for effecting the curing of the composition. 30. A method for filling underneath a space between an electronic component and a carrier substrate the electronic component being mounted on the carrier substrate, comprising the step of dispensing an amount of a composition according to any of claims 1 to 25 to space between the electronic component and the carrier substrate, and exposing the epoxy resin composition to conditions that effect curing. 31. In use of at least one solid organic acid having a pKa of less than or equal to about 12.0, suitably less than or equal to about 10.0, more adequately less than or equal to about 9.0, and desirably less than or equal to to about 7.5, in an adhesive composition of one part comprising (i) an epoxy compound having two or more epoxy groups per molecule, (ii) a polythiol compound having two or more thiol groups per molecule, and (iii) a latent hardener, to stabilize the chemical and physical properties of the composition. 32. The use of at least one solid organic acid having a pKa of less than or equal to about 12.0, suitably less than or equal to about 10.0, more adequately less than or equal to about 9.0, and desirably less than or equal to to about
7. 7.5, in a one-part adhesive composition comprising (i) an epoxy compound having two or more epoxy groups per molecule, (ii) a latent hardener, and (iii) a thixotropy-conferring component, to stabilize the properties Chemical and physical composition.