Low-temperature curable one-component epoxy composition containing a resin block urea-curable substance

Abstract

This disclosure provides latent curing accelerators and compositions containing such latent curing accelerators together with a substance to be cured (e.g., epoxy resin). The latent curing accelerator comprises a urea compound and an encapsulant system having a polyphenol resin and / or at least one additional excipient. Methods for production and use are further provided.

Description

[Technical Field]

[0001] Background of the Invention Epoxy adhesives are used in a wide range of applications in automotive, electronics, aerospace, and general industry. They are increasingly replacing conventional bonding systems such as soldering, welding, riveting, nails, screws, and bolts to offer advantages over these systems. Some of these advantages include the ability to bond similar and different substrates without damage, better stress distribution over a wide area, better fatigue resistance, and noise and vibration resistance.

[0002] Compositions containing epoxy resins and hardeners have been known for decades. Many hardeners react with epoxy resins at room temperature and must be mixed immediately before use. Other hardeners, known as latent hardeners, are stable at ambient temperature when mixed with epoxy resins and only harden when heated to high temperatures. Some compounds also act as latent hardeners, accelerators of dicyandiamide (DICY), or acid anhydrides, resulting in the hardening of epoxy resins at high temperatures. One-component epoxy adhesive systems are preferred over two-component systems because they eliminate the mixing step, application time, and cooling during storage and transport that are associated with two-component systems.

[0003] U.S. Patent No. 4,866,133 describes the use of a solid solution of polymer polyvalent phenols and polyamines for curing epoxy resins. U.S. Patent No. 4,689,390 describes the preparation of latent curing agents by reacting diamines having tertiary amine groups and primary or secondary amino groups with polyepoxy compounds and phenolic resins or phenolic compounds. A solution of tertiary polyamines in polyphenolic resins made from bisphenol A diglycidyl ether and polyamino secondary amines is described as a latent epoxy curing agent in U.S. Patent Application No. 13 / 075403. U.S. Patent No. 7,910,667 describes a polyphenolic resin solution of a polyurea derivative of a tertiary polyamine used as a latent epoxy curing agent. U.S. Patent No. 9,546,243 describes a polyphenolic resin solution of a specific class of amines used as a sole latent epoxy curing agent and DICY accelerator. Finally, U.S. Patent No. 9,000,120 reports a thermally activated DICY accelerator comprising a tertiary amine and a novolac resin.

[0004] This invention relates to latent curing agents and accelerators for epoxy resins, including 100% solid epoxy compositions and aqueous compositions, particularly one-component 100% solid epoxy compositions. A “latent” curing agent is a curable substance in a compounded epoxy system that remains inert under normal ambient conditions but readily reacts with the epoxy resin at high temperatures. An “accelerator” is a material that promotes the reaction between the epoxy resin and the curing agent. A “one-component” epoxy composition is typically a blend of epoxy resin, curing agent, and optionally an accelerator, as well as additives and fillers. “100% solid” means that the epoxy composition does not contain water or organic solvents. There is a need for latent epoxy curing agents or accelerators that exhibit long-term storage stability at ambient temperatures and rapidly cure above 100°C.

[0005] Summary of the Invention Accordingly, this specification provides epoxy curing agents and related compositions that enable lower curing temperatures without impairing the potential of the epoxy resin composition.

[0006] The inventors have found that it is possible to obtain an epoxy curing agent having improved storage stability and a lower curing temperature through a solution containing a urea compound in combination with a polyphenol resin and / or one or more monomer or polymer compounds, any of which may be functionalized with acidic substituents that can interact with tertiary amines, such as OH, COOH, SO3OH, PO(OH)3, and PO(OH)2. Non-functional compounds or polymers do not have these functional groups and do not interact with tertiary amines.

[0007] In the first aspect, this disclosure is: Urea compounds and, Polyphenol resin and An additional excipient selected from functional and / or non-functional components, The subject is a latent curing accelerator composition [Composition 1] that includes an encapsulating agent system containing the above.

[0008] In some embodiments, composition 1 is defined as follows: 1.1 Composition 1, wherein the urea compound comprises a reaction product of an isocyanate and an alkylated polyalkylene polyamine. 1.2 Composition 1 or 1.1 in which the isocyanate is selected from the group consisting of aliphatic isocyanates, alicyclic isocyanates, and aromatic isocyanates. 1.3 Any of the above compositions, wherein the isocyanate is selected from the group consisting of phenyl isocyanate, toluene diisocyanate (TDI), methylenediphenyl diisocyanate (MDI), and polymer methylenediphenyl diisocyanate. 1.4 Alkylated polyalkylene polyamines are at least one primary or secondary amine and formula (A): [ka] Any of the aforementioned compositions having at least two tertiary amines of the formula (wherein R1, R2, R3, R4, and R5 are independently hydrogen, methyl, or ethyl, m and n are independently integers from 1 to 6, and X is an integer from 1 to 10). 1.5 The aforementioned composition, wherein R1 is hydrogen or methyl, R2 and R4 are methyl, and R3 and R5 are hydrogen or methyl. 1.6 Any of the above compositions, wherein the alkylated polyalkylene polyamine is N'-(3-dimethylaminopropyl)-N,N-dimethylpropane-1,3-diamine (Polycat® 15) or poly-N-methyl-azetidine. 1.7 Composition 1, wherein the urea compound comprises a reaction product of a primary amine having a tertiary amine functional group and urea (carbamide). 1.8 The aforementioned composition, wherein the urea compound is 1,3-bis[3-(dimethylamino)propyl]urea (DABCO NE1082). 1.9 Any of the aforementioned compositions, wherein the urea compound is present in an amount of about 5% to about 75% by weight, based on the total weight of the composition. 1.10 Polyphenol resin is formula (B): [ka] (In the formula, R a , R b , R c and R d Each is independently of hydrogen or branched or unbranched C1-C 17 Any of the aforementioned compositions, which is a phenolic resin (where n is an integer from 0 to 50) that is an alkyl group. 1.11 Any of the above compositions, wherein the polyphenol resin contains or consists of a phenol novolac resin. 1.12 Any of the above compositions, wherein the polyphenol resin is a phenol-formaldehyde resin. 1.13 Any of the above compositions, wherein the polyphenol resin is Alnovol PN320. 1.14 Any of the aforementioned compositions, wherein the polyphenol resin is present in an amount of about 5% to about 75% by weight based on the total weight of the composition. 1.15 Any of the aforementioned compositions, wherein the additional excipient is a functional compound comprising one or more of (a) a monomeric carboxylic acid, sulfonic acid, phosphonic acid, phosphoric acid, or boric acid, (b) a polyester resin, (c) an acrylic resin, (d) a polyether resin, (e) a polybutadiene resin, and (f) a polyamide resin. 1.16 Any of the aforementioned compositions, wherein the additional excipient is present in an amount of about 5% to about 75% by weight based on the total weight of the composition. 1.17 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of a functional compound present in an amount of about 5% to about 75% by weight based on the total weight of the composition. 1.18 Any of the aforementioned compositions, wherein the additional excipient is a monomeric carboxylic acid, sulfonic acid, phosphonic acid, phosphoric acid, or boric acid. 1.19 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of a monomeric carboxylic acid. 1.20 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of a monomeric sulfonic acid. 1.21 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of a monomeric phosphonic acid. 1.22 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of a monomeric phosphoric acid. 1.23 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of a monomeric boric acid. 1.24 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of a polyester resin. 1.25 The polyester resin has the following formula:

Chemical formula

[0009] In a second aspect, this disclosure is: Urea compounds and, An additional excipient selected from functional and / or non-functional components, The subject is a latent curing accelerator composition [Composition 2] that includes an encapsulating agent system containing the above.

[0010] In some embodiments, composition 2 is defined as follows: 2.1 Composition 2, wherein the urea compound comprises a reaction product of an isocyanate and an alkylated polyalkylene polyamine. 2.2 Composition 2 or 2.1, wherein the isocyanate is selected from the group consisting of aliphatic isocyanates, alicyclic isocyanates, and aromatic isocyanates. 2.3 Any of the above compositions, wherein the isocyanate is selected from the group consisting of phenyl isocyanate, toluene diisocyanate (TDI), methylenediphenyl diisocyanate (MDI), and polymer methylenediphenyl diisocyanate. 2.4 Alkylated polyalkylene polyamines comprising at least one primary or secondary amine and formula (A): [ka] Any of the aforementioned compositions having at least two tertiary amines of the formula (wherein R1, R2, R3, R4, and R5 are independently hydrogen, methyl, or ethyl, m and n are independently integers from 1 to 6, and X is an integer from 1 to 10). 2.5 The aforementioned composition, wherein R1 is hydrogen or methyl, R2 and R4 are methyl, and R3 and R5 are hydrogen or methyl. 2.6 Any of the above compositions, wherein the alkylated polyalkylene polyamine is N'-(3-dimethylaminopropyl)-N,N-dimethylpropane-1,3-diamine (Polycat® 15) or poly-N-methyl-azetidine. 2.7 Composition 2, wherein the urea compound comprises a reaction product of a primary amine having a tertiary amine functional group and urea (carbamide). 2.8 The composition described above, wherein the urea compound is 1,3-bis[3-(dimethylamino)propyl]urea (DABCO NE1082). 2.9 Any of the aforementioned compositions, wherein the urea compound is present in an amount of about 5% to about 75% by weight, based on the total weight of the composition. 2.10 Any of the aforementioned compositions, wherein the additional excipient is a functional compound comprising one or more of (a) monomeric carboxylic acid, sulfonic acid, phosphonic acid, phosphoric acid, or boric acid, (b) polyester resin, (c) acrylic resin, (d) polyether resin, (e) polybutadiene resin, and (f) polyamide resin. 2.11 Any of the aforementioned compositions, wherein the additional excipient is present in an amount of about 5 wt% to about 75 wt% based on the total weight of the composition. 2.12 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of a functional compound present in an amount of about 5 wt% to about 75 wt% based on the total weight of the composition. 2.13 Any of the aforementioned compositions, wherein the additional excipient is monomeric carboxylic acid, sulfonic acid, phosphonic acid, phosphoric acid, or boric acid. 2.14 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of monomeric carboxylic acid. 2.15 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of monomeric sulfonic acid. 2.16 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of monomeric phosphonic acid. 2.17 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of monomeric phosphoric acid. 2.18 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of monomeric boric acid. 2.19 Any of the aforementioned compositions, wherein the additional excipient comprises or consists of polyester resin. 2.20 The polyester resin has the following formula: [Chemical formula] (In the formula, R1 is saturated or unsaturated alkyl or aryl, R2 is C 1-10 alkyl or C 1-10 cycloalkyl, and n is from 0 to 20), of the aforementioned composition. 2.21 Any of the above compositions, wherein the polyester resin is a polycondensation product of a polyhydric alcohol and a polyhydric carboxylic acid, for example, a polycondensation product of a polyhydric alcohol and a polyhydric carboxylic acid, for example, a dicarboxylic acid, a di-alcohol (diol), and a trifunctional alcohol or carboxylic acid. 2.22 Any of the above compositions, wherein the additional excipient includes or consists of an acrylic resin. 2.23 Acrylic resin is given by the following formula: [ka] (In the formula, R1 is H or CH3, R2 is C 1-8 The aforementioned composition having a structure that is alkyl. 2.24 Any of the above compositions, wherein the acrylic resin is formed by free radical polymerization of acrylic monomers and vinyl monomers together with unsaturated monomers containing hydroxyl or carboxyl groups. 2.25 Any of the above compositions, wherein the additional excipient comprises or consists of a polyether resin. 2.26 Any of the above compositions, wherein the additional excipient is polyalkylene glycol. 2.27 The aforementioned composition, wherein the polyalkylene glycol has a molecular weight of approximately 1,000D to approximately 100,000D. 2.28 The aforementioned composition, wherein the polyalkylene glycol has a molecular weight of approximately 1,500D to approximately 35,000D. 2.29 The aforementioned composition, wherein the polyalkylene glycol has a molecular weight of approximately 1,500D to approximately 10,000D. 2.30 Any of the above compositions, wherein the additional excipient comprises or consists of a polybutadiene resin. 2.31 The above-mentioned composition, wherein the polybutadiene resin is carboxylated polybutadiene. 2.32 The above-mentioned composition, wherein the carboxylated polybutadiene has a polybutadiene skeleton microstructure consisting of a combination of vinyl 1,2-bonds, trans 1,4-bonds, and cis 1,4-bonds. 2.33 Any of compositions 2.31 to 2.32, wherein the carboxylated polybutadiene has an average molecular weight of approximately 500D to approximately 10,000D. 2.34 Any of compositions 2.31 to 2.33, wherein the carboxylated polybutadiene has a molecular weight of approximately 1,000 D to approximately 7,000 D. 2.35 Any of compositions 2.31 to 2.34, wherein the carboxylated polybutadiene has a molecular structure consisting of 70-90% cis double bonds, 10-30% trans double bonds, and 0-3% vinyl double bonds. 2.36 Any of compositions 2.31 to 2.35, wherein the carboxylated polybutadiene is a maleic anhydride adduct of cis-1,4-polybutadiene (e.g., low molecular weight cis-1,4-polybutadiene) having succinic anhydride pendant groups randomly distributed in the polymer chain. 2.37 Any of the above compositions, wherein the additional excipient comprises or consists of a polyamide resin. 2.38 The aforementioned composition, wherein the polyamide resin is nylon (e.g., nylon-6, nylon-6-6, copolymers of nylon-6 and nylon-6-6, nylon-9, nylon-10, nylon-11, nylon-12, nylon-6-10), aromatic polyamides, elastomer polyamides, and mixtures thereof. 2.39 Any composition from 2.37 to 2.38, wherein the polyamide resin is an acid-functional thermoplastic polyamide. 2.40 Any of the aforementioned compositions, wherein the additional excipient is a non-functional component, which is a polymer compound selected from acrylates, polybutadienes, polyamides, ketone aldehyde condensation resins, polyimides, styrene-butadiene resins, olefin copolymers, and combinations thereof. 2.41 Any of the aforementioned compositions, wherein the additional excipients include or consist of a non-functional compound present in an amount of about 5% to about 75% by weight, based on the total weight of the composition. 2.42 Any of the aforementioned compositions, which do not gel after 4 weeks under accelerated degradation conditions (i.e., storage at 40°C for 4 weeks). 2.43 Any of the aforementioned compositions, wherein the composition is in liquid or solid powder form. 2.44 Any of the above compositions, wherein the composition is in the form of an aqueous solution. 2.45 Any of the above compositions further comprising one or more wetting agents, fillers, defoamers, and rheological modifiers. 2.46 Any of the above compositions, wherein the composition is a latent curing agent for epoxy resin (e.g., a sole latent curing agent).

[0011] In a third embodiment, this disclosure is, Latent curing accelerator compositions (i.e., Composition 1 and subsequent compositions or Composition 2 and subsequent compositions), and This applies to curable epoxy systems [System 1] that include epoxy resin.

[0012] In some embodiments, System 1 is defined as follows: 1.1 System 1, wherein the latent curing accelerator composition is composed of any of the following compositions. 1.2 System 1, wherein the latent curing accelerator composition is composed of any of composition 2 and subsequent compositions. 1.3 Any of the aforementioned systems, wherein the epoxy is a glycidyl ether, a polyhydric phenol, or an alicyclic epoxide (including diepoxides of alicyclic esters of dicarboxylic acids). 1.4 Epoxy is given by the following formula: [ka] Any system that is a polymer of the formula (where m is an integer and R is a divalent hydrocarbon group of divalent phenol). 1.5 The system is one of the aforementioned systems having an onset temperature of approximately 135°C to approximately 142°C. 1.6 is one of the aforementioned systems having a viscosity of approximately 19,000 cP to approximately 21,000 cP. 1.7 One of the aforementioned systems that does not gel after 4 weeks under accelerated degradation conditions (i.e., 4 weeks of storage at 40°C). 1.8 is one of the aforementioned systems that provides a lap shear strength exceeding 700 psi. 1.9 Any of the aforementioned systems, wherein the additional excipient in the latent-enhancing agent composition is an acrylic resin, and the system gives a wrap shear strength of more than 700 psi. 1.10 One of the aforementioned systems that provides an adhesive strength of approximately 60 pli to 120 pli, as determined by a T-type peel test. 1.11 Any of the aforementioned systems, wherein the additional excipient in the latent-enhancing agent composition is an acrylic resin, and the system yields an adhesive strength of approximately 60 pli to 120 pli, as determined by a T-type peel test. 1.12 Any of the above systems further comprising one or more of a wetting agent, a filler, an antifoaming agent, and a rheological modifier. 1.13 Any of the above systems, wherein the latent curing accelerator composition is a latent curing agent for epoxy resins (e.g., a sole latent curing agent). 1.14 Any of the aforementioned systems, further including DICY.

[0013] In a fourth aspect, the present disclosure relates to a method for curing a substance by the use of a latent curing accelerator composition [Method 1], The method relates to a method comprising the steps of combining a substance with a latent curing accelerator composition and heating the resulting mixture.

[0014] In some embodiments, Method 1 is defined as follows: 1.1 Method 1, where the substance is epoxy resin. 1.2 The latent curing accelerator composition is composition 1 and subsequent methods 1 or 1.1. 1.3 The latent curing accelerator composition is Method 1 or 1.1 according to Composition 2 and subsequent methods. 1.4 Any of the methods described above, which involves heating a mixture containing a substance containing a latent curing accelerator to a temperature of approximately 135°C to approximately 142°C. 1.5 Any of the above methods, wherein the latent curing accelerator composition is formed by blending an encapsulating agent system under a nitrogen atmosphere and heating to a temperature of 120°C to 180°C. 1.6 Any of the above methods, wherein the composition is a latent curing agent for epoxy resins (e.g., a sole latent curing agent). 1.7 Any of the above methods, wherein the composition is used as a curing agent such as DICY or as an accelerator for an acid anhydride for epoxy resins. 1.8 Any of the methods described above, in which the composition is used as a latent curing accelerator for structural adhesives and composites, electrical potting and encapsulation, reinforcement and / or damping, in-situ curing pipes, impact adhesives, filament winding, transfer molding powder, prepregs containing solid or liquid epoxy, sheet molding compounds, coatings for concrete, wood, metal, etc., resin transfer molding, and / or battery pack adhesives.

[0015] This disclosure further provides latent curing accelerator compositions for use in methods for curing materials, for example, for use in Method 1 and any of the subsequent methods.

[0016] This disclosure further provides the use of latent curing accelerator compositions in the manufacture of curable formulations, including a substance and a latent curing accelerator composition, for use in Method 1 and any of the subsequent methods.

[0017] All aspects and embodiments of the present invention disclosed herein are to be used individually and in all possible combinations thereof with all other aspects and embodiments of the present invention disclosed herein.

[0018] Detailed description of the invention This disclosure provides latent curing accelerators and compositions containing such latent curing accelerators together with a substance to be cured (e.g., epoxy resin). Methods for manufacturing and using these are further provided.

[0019] The present invention relates to specific urea-(resin 1:resin 2) compound reaction product compositions, and their use as curing agents for curing epoxy resin compositions, or as accelerators for latent curing agents such as dicyandiamide, mercaptan, or acid anhydride.

[0020] In one embodiment, the latent curing agent and the latent curing agent accelerator are compositions which are reaction products of (a) a urea compound and (b) a phenolic resin (resin 1) combined with (c) another type of functional or non-functional monomer compound or polymer resin (resin 2).

[0021] In another embodiment, the latent curing agent and the latent curing agent accelerator are compositions which are reaction products of (a) a urea compound and (c) another type of functional or non-functional monomer compound or polymer resin (resin 2).

[0022] urea compound The latent curing accelerator of this disclosure includes an inclusion agent system containing a urea compound as its main component.

[0023] In one preferred embodiment of the present invention, the urea compound (a) comprises an isocyanate and at least one primary or secondary amine and formula (A): [ka] The reaction product is an alkylated polyalkylene polyamine having at least two tertiary amines of the formula (wherein R1, R2, R3, R4, and R5 independently represent hydrogen, methyl, or ethyl; m and n independently are integers from 1 to 6; and X is an integer from 1 to 10). In another preferred embodiment, R1 represents hydrogen or methyl; R2 and R4 represent methyl; and R3 and R5 represent hydrogen or methyl, i.e., a methylated polyalkylene polyamine.

[0024] For each of the aforementioned embodiments and other preferred embodiments, the R1-R5 substituents are selected individually or in any combination, as long as the amine molecule has one primary or secondary amine and at least two tertiary amines.

[0025] In yet another preferred embodiment of each of the aforementioned aspects and embodiments, integers m, n, and X are selected individually or in any combination with each other over the range described above, where a particular aspect of m and n is 2 or 3, X is 1 to 7, m and n is 3, X is 1, m and n is 3, X is 1 to 7.

[0026] Preferred isocyanates useful for reaction with polyalkylene polyamines are aliphatic isocyanates, alicyclic isocyanates, and aromatic isocyanates in which the isocyanate functional group -NCO is directly bonded to the aromatic ring. Preferred isocyanates include phenyl isocyanate, toluene diisocyanate (TDI) including 2,4-TDI, 2,6-TDI, and 2,4 / 2,6-TDI, and methylenediphenyl diisocyanate (MDI) including its polymethylene polyphenylene poly(isocyanate) polymer homolog, i.e., polymer MDI.

[0027] The urea compounds of the present invention can be prepared by reactions well known to chemists and have been reported in literature such as Jerry March, Advanced Organic Chemistry, Wiley-Interscience, Fourth Edition, page 1299. In one embodiment, the isocyanate and polyamine are reacted at a high temperature of 50-100°C in an inert atmosphere at ambient pressure, optionally in a solvent such as toluene, in a polyamine:isocyanate equivalent ratio of 1:1 for a polyamine having one primary or secondary amine and an isocyanate having one NCO group, 1:2 for a polyamine having a total of two primary and / or secondary amines and an isocyanate having one NCO group, and 2:1 for a polyamine having one primary or secondary amine and an isocyanate having two NCO groups. Furthermore, urea compounds are commercially available from Sigma Aldrich, Evonik Industries AG, Huntsman, and AlChem.

[0028] In one preferred embodiment of the present invention, preferred polyalkylene polyamines for reaction with isocyanates include 3,3'-iminobis(N,N-dimethylpropylamine), also known as N'-(3-dimethylaminopropyl)-N,N-dimethylpropane-1,3-diamine and available from Evonik Industries AG as the Polycat® 15 catalyst, and poly-N-methylazetidine, the preparation and structure of which are taught in U.S. Patent Application Publication No. 2008-0194776 (the disclosure of which is incorporated herein by reference). This embodiment is intended to be combined with all other disclosed aspects and embodiments of the present invention.

[0029] In another preferred embodiment of the present invention, urea compound (a) is a reaction product of a primary amine having a tertiary amine functional group and urea (carbamide). For example, 1,3-bis[3-(dimethylamino)propyl]urea (DABCO NE1082) is an example of this type of urea compound and is available from Evonik Corporation.

[0030] Polyphenol resin In various embodiments, the encapsulating system of the present disclosure further comprises a phenolic resin. The chemical structure of such a phenolic resin is given by the following formula (B): [ka] (In the formula, R a , R b , R c and R d Each is independently of hydrogen or branched or unbranched C1-C 17 It is an alkyl group, and n is an integer from 0 to 50. In a preferred embodiment, R a , R b , R c and R d Each is independently of hydrogen or branched or unbranched C1-C 10 It is an alkyl group, where n is an integer from 1 to 20. In these preferred embodiments, preferred alkyl groups include methyl, ethyl, n-propyl, isopropyl, and all isomers of octyl, decyl, and dodecyl, including butyl, pentyl, hexyl, and 2-ethylhexyl. In another preferred embodiment of the phenolic resin, R a -R d Each of these is hydrogen. In other preferred embodiments of the aforementioned aspects and embodiments, R a -R d Substituents can be selected individually or in any combination.

[0031] In preferred embodiments of the present invention, the phenolic resin is a novolac resin, which is a compound formed by the condensation of phenol with an aldehyde, particularly formaldehyde. The novolac resin is a reaction product of a mono- or dialdehyde, most commonly formaldehyde, with a mono- or polyphenolic material. Preferred examples of monophenolic materials that can be used include phenol, cresol, p-tert-butylphenol, nonylphenol, octylphenol, and other alkyl and phenyl-substituted phenols. Preferred examples of polyphenolic materials include various diphenols, including bisphenol-A and bisphenol-F. Preferred aldehydes that can be used in the novolac resin include formaldehyde, glyoxal, and higher aldehydes up to about C4. A preferred novolac resin is typically a complex mixture having varying degrees of hydroxyl functional groups.

[0032] Preferably, novolac resins can be prepared by the reaction of a phenol or substituted phenol with an aldehyde, particularly formaldehyde, in the presence of an acid or base. Preferred novolac resins are phenol-formaldehyde resins with a weight-average molecular weight of 10,000 to 25,000 (e.g., Alnovol™ PN-320 available from Allnex GmbH).

[0033] Additional excipients In various embodiments, the encapsulation systems of the present disclosure further include additional excipients, which may be functional or non-functional monomer or polymer compounds. Exemplary excipients are provided below. In various embodiments, the additional excipients may be present in an amount of about 5% to about 75% by weight, based on the total weight of the composition. If one or more additional excipients are present, this concentration may refer to the total amount of additional excipients or to individual additional excipients.

[0034] functional compound The functional compounds according to this disclosure preferably include a variety of chemical species such as phenols, alkyl or aryl-substituted carboxylic acids, sulfonic acids, phosphoric acids, phosphonic acids, and boric acids.

[0035] Preferred phenol compounds that can be used include phenols or substituted phenols (substituents include alkyl, aryl ether, amino groups, or halogen atoms), such as p-tert-butylphenol, p-sec-butylphenol, o-tert-butylphenol, o-sec-butylphenol, p-tert-amylphenol, p-tert-octylphenol, p-nonylphenol, p-cumylphenol, p-dodecylphenol, styrylphenol, 2,6-di-tert-butylphenol, 2,4-di-tert-butylphenol, di-sec-butylphenol, 2,4-di-tert-amylphenol, 2,4-di-cumylphenol, o-cumyloctylphenol, α-naphthol, β-naphthol, bis-phenol A, bis-phenol F, bis-phenol TMC, and mixtures thereof, comprising at least one member selected from the group.

[0036] Preferred carboxylic acids that can be used include at least one member selected from the group consisting of acetic acid, propanoic acid, hexanoic acid, 2-ethylhexanoic acid, decanoic acid, stearic acid, benzoic acid, salicylic acid, tall oil fatty acids (TOFAs), dimer acids, and mixtures thereof.

[0037] It is intended that a variety of other acid-functional compounds may be used in the compositions of the present disclosure. Non-limiting examples of such compounds include sulfonic acids, such as p-toluenesulfonic acid, methanesulfonic acid, dodecylbenzenesulfonic acid, trifluoromethanesulfonic acid, phosphonic acid, phosphoric acid, and boric acid.

[0038] Functional polymer compounds include a variety of chemicals, such as polyesters, acrylics, polyethers, polybutadienes, polyamides, and combinations thereof. As used herein, the terms “functional” or “functionalized” refer to a compound or polymer that contains, or is modified to contain, one or both a carboxyl group and / or a hydroxyl group.

[0039] Polyester resin Polyester resins are generally polycondensation products of polyalcohols and polycarboxylic acids. According to this disclosure, the polyester resin is preferably a polycondensation product of a polyhydric alcohol and a polyhydric carboxylic acid, and more preferably a polycondensation product of a dicarboxylic acid, a dihydric alcohol (diol) and a trifunctional alcohol or carboxylic acid.

[0040] The chemical structure of such polyester resins is as follows: [ka] (In the formula: R1 = saturated or unsaturated alkyl or aryl, R²=C 1-10 Alkyl or C 1-10 It is a cycloalkyl, This is shown for n=0 to 20.

[0041] Preferred examples of polycarboxylic acids, particularly dicarboxylic acids that can be used in the preparation of polyester resins, include isophthalic acid, terephthalic acid, hexahydroterephthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4-oxybisbenzoic acid, 3,6-dichlorophthalic acid, tetrachlorophthalic acid, tetrahydrophthalic acid, hexahydroterephthalic acid, hexachloroendomethylenetetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, phthalic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid, maleic acid, fumaric acid, adipic acid, succinic acid, and trimellitic acid. These polycarboxylic acids can be used in their acidic form or in the form of their anhydrides, acyl chlorides, or lower alkyl esters. Mixtures of polycarboxylic acids can also be used. Furthermore, hydroxycarboxylic acids and lactones can be used. Preferred examples include hydroxypivalic acid and ε-caprolactone. Monofunctional carboxylic acids may be used to block polymer chains.

[0042] Polyester resins can be prepared by reacting polyalcohols, particularly diols, with the above-mentioned carboxylic acids or their analogues. Examples of polyalcohols include aliphatic diols, such as ethylene glycol, propane-1,2-diol, propane-1,3-diol, butane-1,2-diol, butane-1,4-diol, butane-1,3-diol, 2,2-dimethylpropane-1,3-diol (neopentyl glycol), hexane-2,5-diol, hexane-1,6-diol, 2,2-bis-(4-hydroxycyclohexyl)-propane (hydrogenated bisphenol-A), 1,4-dimethylolcyclohexane, diethylene glycol, dipropylene glycol, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, hydroxypivalate ester of neopentyl glycol, 4,8-bis-(hydroxymethyl)tricyclo[5,2,1,0]decane (=tricyclodecanedimethylol), and 2,3-butenediol.

[0043] Branched polyesters can be obtained using trifunctional or higher alcohols or carboxylic acids. Preferred examples of suitable trifunctional or higher alcohols or carboxylic acids include, but are not limited to, glycerol, hexanetriol, trimethylolethane, trimethylolpropane, pentaerythritol and sorbitol, trimellitic acid, trimellitic anhydride, pyromellitic acid, and dimethylolpropionic acid (DMPA).

[0044] Polyesters can be prepared by generally known polymerization methods such as conventional esterification and / or transesterification, or by esterification and / or transesterification using catalysts. Useful catalysts include organotin compounds and organotitanium compounds. Polyester resins useful in this invention may be hydroxyl or carboxyl functional. The conditions and COOH / OH ratio for preparing the polyester resin can be selected to obtain a final product having an acid value or hydroxyl value within the intended range. A polyester resin is classified as acid-functional if its hydroxyl value is lower than its acid value (AV). A resin is classified as hydroxyl-functional if its acid value is lower than its hydroxyl value. Hydroxyl-functional resins should have a hydroxyl value greater than about 1 to about 200, and carboxyl-functional polyesters should have an acid value greater than about 1 to about 200. Polyester compounds may be liquids, solids, or solutions in organic solvents.

[0045] Acrylic resin Preferably, acrylic polymers useful in the present invention can be prepared by free radical polymerization of acrylic monomers and vinyl monomers with unsaturated monomers having hydroxyl or carboxyl groups. Preferred acrylic resins include those having hydroxyl functional groups with a hydroxyl value of more than 1 to 200 and carboxyl functional groups with an acid value of more than 1 to 300. The preferred softening point of the acrylic polymer is about 50°C to 200°C.

[0046] Preferred functional monomers are selected from acrylic acid, methacrylic acid, crotonic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate. Other preferred acrylic monomers can be selected from the group consisting of esters of α,β-ethylenically unsaturated carboxylic acids having 3 to 8 carbon atoms. Preferred acrylic monomers are given by formula: [ka] (In the formula: R1 is either H or methyl. R2 is C 1-8 It has (being alkyl).

[0047] Preferred acrylic monomers for the compositions of this disclosure include ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, and lauryl methacrylate.

[0048] In various embodiments, preferred acrylic polymers may optionally contain ethylenically monounsaturated vinyl comonomers distinct from functional monomers and acrylic monomers. Examples of potentially useful and preferred ethylenically unsaturated vinyl comonomers include styrene, propylene, vinyltoluene, dimethylstyrene, α-methylstyrene, and vinyl acetate. Acrylic compounds may be liquids, solids, or solutions in organic solvents.

[0049] Preferably, copolymers can be prepared by free radical polymerization in any known form, preferably in bulk, solution, emulsion, or suspension. Preferably, the reaction is carried out in the presence of a free radical initiator, such as an azo compound, such as benzoyl peroxide, tert-butyl peroxide, decanoyl peroxide, or azobisisobutyronitrile. Preferably, such initiators are present in an amount ranging from 0.1 to about 5% by weight of the total monomers.

[0050] In various embodiments, commercially available acrylic resins used in the compositions of this disclosure include ISOCRYL C-78 (sold by Estron Chemical Inc.), EPOMATT G-152 (sold by Estron Chemical Inc.), and JONCRYL 67 (sold by BASF).

[0051] Polyether resin A preferred polyether resin used in the compositions of this disclosure is polyalkylene glycol. Preferably, the polyalkylene glycol may have a molecular weight of 1,000 to 100,000 D [Daltons], preferably 1,500 to 35,000 D, and particularly preferably 1,500 to 10,000 D. A particularly preferred polyalkylene glycol is polyethylene glycol. Furthermore, polypropylene glycol, polytetrahydrofuran, or polybutylene glycol are also suitable, and these are obtained from 2-ethyloxirane or 2,3-dimethyloxirane. Other suitable polyethers are random or block copolymers of polyalkylene glycols obtained from ethylene oxide, propylene oxide, and butylene oxide, for example, polyethylene glycol-polypropylene glycol block copolymer. The block copolymer may be of type AB or ABA.

[0052] More preferable polyalkylene glycols include those alkylated at one or both terminal OH groups. Suitable alkyl groups include branched or linear C1-~C 22-Alkyl alkyl group, preferably C1-C 18 -Alkyl groups, such as methyl, ethyl, n-butyl, isobutyl, pentyl, hexyl, octyl, nonyl, decyl, dodecyl, tridecyl, or octadecyl groups.

[0053] Preferred polyalkylene glycols also include those that are acid-capped at one or both terminal OH groups. An example of such a preferred polyalkylene glycol is a phosphonic acid-terminated polyether. Another example of a preferred polyalkylene glycol is a polyoxyethylene chain grafted onto a polycarboxylate-type skeleton.

[0054] The method for producing polyether copolymers according to this disclosure is generally known in the prior art. Preparation is preferably carried out by free radical polymerization in solution, in a non-aqueous organic solvent, or in a non-aqueous / aqueous mixed solvent. Suitable preparation processes are described, for example, in International Publication Nos. 2007 / 051743 and International Publication Nos. 2009 / 013202, and the disclosure relating to the preparation processes is incorporated herein by reference in whole.

[0055] Polybutadiene resin Preferred examples of polybutadiene-based polyol resins used in the compositions of the present invention include homopolymers, such as 1,2-polybutadiene polyol and 1,4-polybutadiene polyol; copolymers, such as poly(pentadiene butadiene) polyol, poly(butadiene styrene) polyol and poly(butadiene acrylonitrile) polyol; and hydrogenated polybutadiene-based polyol resins obtained by hydrogenating these polyol resins. These polybutadiene-based polyol resins are commercially available, for example, from Idemitsu Kosan Co., Ltd. as Poly bd R-15HT (hydroxyl value = 102.7 mg KOH / mg, Mw 1200) and Poly bd R-45HT (hydroxyl value = 46.6 mg KOH / mg, Mw 2800).

[0056] Furthermore, due to the advantages of this disclosure, the hydroxyl value of the polybutadiene-based polyol resin is preferably 40 to 330 mg KOH / g, more preferably 40 to 110 mg KOH / g. The polybutadiene-based polyol resin also has a weight-average molecular weight (GPC) of preferably 50 to 3,000, more preferably 800 to 1,500. Other preferred polybutadiene resins suitable for use in the compositions of this disclosure include carboxylated polybutadiene, which may be in the form of a liquid polymer having a polybutadiene skeletal microstructure consisting of a combination of vinyl 1,2-bonds, trans 1,4-bonds, and cis 1,4-bonds, and is transparent at room temperature. The vinyl 1,2-bonds are preferably 30 wt% or less. The cis 1,4-bonds are preferably 40 wt% or more. If the cis 1,4-bonds are less than 40 wt%, it may lead to a decrease in the adhesion of the resulting composition and is therefore undesirable.

[0057] The carboxylated polybutadiene component can be obtained by reacting a carboxyl group-introduced compound with liquid polybutadiene. The 1,3-butadiene and carboxyl group-introduced compound constituting the liquid polybutadiene are preferably used in proportions of 80-98% by mass (1,3-butadiene) and 2-20% by mass (carboxyl group-introduced compound), respectively.

[0058] The liquid polybutadiene used in the reaction preferably has a number-average molecular weight of 500 to 10,000, more preferably 1,000 to 7,000. A broad molecular weight distribution is desirable for the liquid polybutadiene. More preferably, the liquid polybutadiene has an iodine value of 30 to 500 g of iodine per 100 g of material, as determined according to DIN 53241. Preferably, the liquid polybutadiene has a molecular structure consisting of 70 to 90% cis double bonds, 10 to 30% trans double bonds, and 0 to 3% vinyl double bonds.

[0059] Preferred examples of carboxyl group-introduced compounds that can be used include ethylene-based unsaturated dicarboxyl compounds, such as ethylene-based unsaturated dicarboxylic acids, and their anhydrides or monoesters. Specific examples of compounds include maleic acid, fumaric acid, itaconic acid, 3,6-tetrahydrophthalic acid, 1,2-dimethylmaleic anhydride, monomethyl maleic acid, or monoethyl maleic acid. Of these, maleic anhydride is preferred due to its safety, economy, and reactivity (polybutadiene maleic acid is preferred).

[0060] Methods for producing polybutadiene / maleic anhydride adducts are generally known in the prior art.

[0061] Maleic acid liquid polybutadiene has an acid value of preferably 50 to 120 mg KOH / g, more preferably 70 to 90 mg KOH / g, as measured according to DIN ISO 3682. If the acid value is less than 50 mg KOH / g, the adhesiveness of the resulting composition will decrease, but if the acid value exceeds 120 mg KOH / g, it will lead to an increase in the viscosity of the resulting composition, reducing its workability. The maleic acid ratio of maleic acid-coated liquid polybutadiene needs to be considered along with viscosity, but is preferably 6-20%, more preferably 6-15%, and even more preferably 7-10%.

[0062] The viscosity of liquid polybutadiene with maleic acid, as determined by DIN 53214 (at 20°C), is preferably 3 to 16 Pa·s, more preferably 5 to 13 Pa·s, and even more preferably 6 to 9 Pa·s.

[0063] Furthermore, the maleic acid-coated liquid polybutadiene contains 30% or less vinyl double bonds. Liquid polybutadiene with cis double bonds within the above range tends to have higher flexibility and a higher maleic acid ratio (i.e., acid value) compared to liquid polybutadiene with cis double bonds at a lower percentage than the above lower limit. As a result, the composition has high adhesion and sufficient polarity, making it possible to produce a more flexible composition and to easily adjust the flexibility of the composition of this disclosure. Moreover, the resulting composition has improved decorative properties.

[0064] The viscosity of liquid polybutadiene with cis double bonds present in a proportion lower than the lower limit mentioned above increases rapidly with increasing maleic acid content, while the viscosity of liquid polybutadiene with cis double bonds within the above range shows only a slight increase. This low viscosity within the above range ensures high reactivity and improves workability. Furthermore, the resulting composition exhibits improved decorative properties.

[0065] Non-limiting examples of polybutadiene resins provided herein are maleic anhydride adducts of cis-1,4-polybutadiene (e.g., low molecular weight cis-1,4-polybutadiene), which may have succinic anhydride pendant groups randomly distributed in the polymer chain. Examples of such polybutadiene resins include POLYVEST OC 800S, POLYVEST OC 1200S, and POLYVEST MA-75, each manufactured by Evonik Industries.

[0066] Polyamide resin Polyamides are typically condensation copolymers formed by the reaction of dicarboxylic acids with diamines or by ring-opening of lactams. Various polyamides can be produced by adjusting the number of carbon atoms. The nomenclature used herein indicates the number of carbon atoms in the diamine first, followed by the number of carbon atoms in the dicarboxylic acid. Thus, polyamide-6,6 has 6 carbons from the diamine and 6 carbons from the dicarboxylic acid, and polyamide-6,12 has 6 carbons from the diamine and 12 carbons from the dicarboxylic acid. Polyamide-6 is a homopolymer formed by ring-opening polymerization (i.e., ring-opening polymerization of caprolactam). Polyamides may also be nylon-9, nylon-12, nylon-11, nylon-4, 6, nylon-6, 10, or any of the polyamides listed herein.

[0067] Polyamide resins useful in the compositions of this disclosure include nylon-6, nylon-6-6, copolymers of nylon-6 and nylon-6-6, nylon-9, nylon-10, nylon-11, nylon-12, nylon-6-10, aromatic polyamides, elastomer polyamides, and mixtures thereof.

[0068] The conditions and COOH / NH2 ratio for preparing polyamide resins can be selected to obtain a final product with an acid value or amine value within the intended range. A polyamide resin is classified as acid-functional if its amine value is lower than its acid value (AV). Evonik's Ancatherm 592 is an example of an acid-functional thermoplastic polyamide.

[0069] Non-functional polymer compounds Examples of non-functional polymer compounds useful in the compositions of this disclosure include polyimides, styrene-butadiene resins, and copolymers of other olefins and combinations thereof.

[0070] Preferred examples of non-functional resin compounds that can be used in combination with phenolic resins in this disclosure include compounds from Evonik's POLYVEST liquid polybutadiene product line, thermoplastic acrylic resins and MBS polymers from Dow's Paraloid product line, non-functional polyamides from Evonik's Vestamid product line, and styrene-based block copolymers (SBCs) from Kraton, produced from butadiene, styrene, and isoprene raw materials. Finally, ketone-aldehyde condensation resins, such as Evonik's TEGO Variplus AP, can also be used in combination with polyphenols in this disclosure.

[0071] Curable epoxy resin All aspects and embodiments of the present invention disclosed herein are intended to be used individually and in all possible combinations thereof with all other aspects and embodiments of the present invention disclosed herein.

[0072] Solutions of urea compounds with phenolic resins and / or other resins and combinations thereof are used as curing agents for epoxy resins. Epoxy resins commercially available under trade names DER 383 or DER 333 (available from Dow) and EPON 826 or EPON 828 (available from Hexion Specialty Chemicals) are suitable for use with the latent curing accelerator compositions of this disclosure.

[0073] Other epoxy resins include, but are not limited to, bifunctional epoxys, such as bisphenol-A and bisphenol-F resins. When used herein, polyfunctional epoxy resins refer to compounds containing two or more 1,2-epoxy groups per molecule. This type of epoxide compound is well known to those skilled in the art and is described by reference in CAMay, ed., Epoxy Resins Chemistry and Technology, as well as in Y. Tanaka, "Synthesis and Characteristics of Epoxides" (Marcel Dekker, 1988).

[0074] One class of epoxy resins suitable for use in this disclosure comprises glycidyl ethers of polyhydric phenols, including glycidyl ethers of dihydric phenols. Exemplary examples include, but are not limited to, glycidyl ethers such as resorcinol, hydroquinone, bis-(4-hydroxy-3,5-difluorophenyl)-methane, 1,1-bis-(4-hydroxyphenyl)-ethane, 2,2-bis-(4-hydroxy-3-methylphenyl)-propane, 2,2-bis-(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis-(4-hydroxyphenyl)-propane (commercially available as bisphenol A), bis-(4-hydroxyphenyl)-methane (commercially available as bisphenol-F, which may contain varying amounts of 2-hydroxyphenyl isomers), or any combination thereof. Furthermore, in this disclosure: [ka] Highly advanced divalent phenols with the structure (wherein m is an integer and R is the divalent hydrocarbon group of a divalent phenol, for example, the divalent phenol described above) are also useful.

[0075] Materials according to this formula can be prepared by polymerizing a mixture of divalent phenol and epichlorohydrin, or by proceeding with a mixture of diglycidyl ether of divalent phenol and divalent phenol. In any given molecule, the value of m is an integer, but the material is always a mixture that can be characterized by an average value of m, which is not necessarily an integer. Polymer materials having an average value of m from 0 to about 7 may be used in one embodiment of the present disclosure. In other embodiments, the epoxy component may be a polyglycidylamine from one or more of 2,2'-methylenedianiline, m-xylenedianiline, hydantoin, and isocyanates.

[0076] The epoxy component may be an alicyclic epoxide. Examples of suitable alicyclic epoxides include diepoxides of alicyclic esters of dicarboxylic acids, such as bis(3,4-epoxycyclohexylmethyl) oxalate, bis(3,4-epoxycyclohexylmethyl) adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, vinylcyclohexene diepoxide; limonene diepoxide; bis(3,4-epoxycyclohexylmethyl) pimelate; dicyclopentadiene diepoxide; and other suitable alicyclic epoxides. Other suitable diepoxides of alicyclic esters of dicarboxylic acids are described, for example, in International Publication No. 2009 / 089145, which is incorporated herein by reference.

[0077] Other alicyclic epoxides include 3,3-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, e.g., 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate; 3,3-epoxy-1-methylcyclohexylmethyl-3,4-epoxy-1-methylcyclohexanecarboxylate; 6-methyl-3,4-epoxycyclohexylmethylmethyl-6-methyl-3,4-epoxycyclohexanecarboxylate; and 3,4-epoxy-2-methylcyclohexylmethyl-3,4-epoxy-3-methylcyclohexanecarboxylate. Other suitable 3,4-epoxycyclohexylmenthyl-3,4-epoxycyclohexanecarboxylates are described, for example, in U.S. Patent No. 2,890,194, which is incorporated herein by reference. In other embodiments, the epoxy component may include polyol polyglycidyl ethers from polyethylene glycol, polypropylene glycol, or polytetrahydrofuran or a combination thereof.

[0078] Resins 1 and 2 are reacted with the urea compound under nitrogen at a high temperature of 120-180°C. A sufficient amount of resin is reacted to block substantially all of the tertiary amine functional groups in the urea composition. Generally, based on the urea compound, about 25% to 100% by weight of resin is added to the urea composition and reacted with it. If phenol resin 1 is not added sufficiently, the resulting product will be sticky and form lumps. If too much is added, the activation temperature for curing the epoxy resin will be too high. After 1 hour of reaction, the hot solution is poured onto a Teflon block or aluminum sheet and cooled to room temperature. The resin can be added to the reactor undiluted as described above, or dissolved in certain polar solvents such as methanol. In the latter case, the resulting reaction mixture is refluxed for 2 hours to form a clear solution. The mixture is then cooled to room temperature and the solvent is removed by evaporation. The resulting product is further dried under vacuum.

[0079] Once recovered from the reactor, the final curing agent mixture is ground into a fine powder using methods such as spray drying, ceramic bead grinding, jet grinding, or coffee grinding. The powder particle size can range from 1 micron to 100 microns. The powder is then incorporated into the epoxy resin and mixed using a speed mixer, Coles blade mixer, or planetary mixer. Optional additives such as wetting agents, fillers, defoamers, and rheology modifiers may be added as needed.

[0080] In one aspect of the present invention, the urea-(resin 1:resin 2) compound reaction product can be used as an epoxy curing agent in one- and two-component epoxy compositions for epoxy applications such as adhesives and composites, decorative and protective coatings including powder coatings, coatings for concrete, wood, metal, etc., filament winding, printed circuit boards, electrical potting and encapsulation, in-situ cured pipes, impact-resistant adhesives, transfer molding powders, prepregs having solid or liquid epoxy, sheet molding compounds, resin transfer molding, and EV battery pack adhesives. Typically, 0.5 to 10 parts by weight (pbw) of the urea-(resin 1:resin 2) compound reaction product, preferably 2 to 6 pbw, of the urea-(resin 1:resin 2) compound reaction product per 100 parts by weight (pbw) of epoxy resin is used in the epoxy composition.

[0081] In another aspect of the present invention, the urea-(resin 1:resin 2) compound reaction product can also be used as an accelerator for curing agents such as dicyandiamide, mercaptan, and acid anhydrides such as acetic anhydride in epoxy applications such as one- and two-component epoxy compositions such as adhesives and composites, decorative and protective coatings including powder coatings, coatings for concrete, wood, metal, etc., filament winding, printed circuit boards, electrical potting and encapsulation, cured pipes, impact-resistant adhesives, transfer molding powders, prepregs containing solid or liquid epoxy, sheet molding compounds, resin transfer molding, and EV battery pack adhesives. Typically, 0.5 to 10 parts by weight (pbw) of curing agent, preferably 2 to 6 pbw, is used in the epoxy composition per 100 parts by weight of epoxy resin, and 0.5 to 10 parts by weight (pbw) of the urea-(resin 1:resin 2) compound reaction product is used as an accelerator in the epoxy composition per 100 pbw of epoxy resin, preferably 2 to 6 pbw.

[0082] The urea-(resin 1:resin 2) compound reaction product, as a curing agent or accelerator for curing agents, is combined with an epoxy resin, which is a polyepoxy compound containing more than one 1,2-epoxy group per molecule. Such epoxides are well known in the epoxy field and are described in CAMay, ed., Epoxy Resins Chemistry and Technology, and Y. Tanaka, "Synthesis and Characteristics of Epoxides," (Marcel Dekker, 1988). An example is the epoxide disclosed in U.S. Patent No. 5,599,855 (Col 5 / 6~6 / 20), which is incorporated by reference. Preferred polyepoxy compounds are diglycidyl ethers of bisphenol-A, advanced diglycidyl ethers of bisphenol-A, diglycidyl ethers of bisphenol-F, and epoxy novolac resins. Both liquid and solid epoxy resins are suitably used in one-component epoxy compositions. The powder coating composition comprises a solid epoxy resin, a urea compound, and a dicyandiamide.

[0083] In one embodiment of the present invention, a one-component epoxy resin composition comprises a contact product of such urea-(resin 1:resin 2) compound reaction product with an epoxy resin as a curing agent. In another embodiment of the present invention, a one-component epoxy resin composition comprises a contact product of dicyandiamide, mercaptan or acid anhydride as a latent curing agent, for example, a urea-(resin 1:resin 2) compound reaction product as a curing agent accelerator with an epoxy resin.

[0084] In another aspect of the present invention, a one-component 100% solid epoxy composition comprising a urea-(resin 1:resin 2) compound reaction product, a latent curing agent, such as dicyandiamide, mercaptan or acid anhydride, and an epoxy resin that provides low-temperature curing and storage stability, i.e., longer latent curing.

[0085] In another aspect of the present invention, a one-component aqueous epoxy composition comprising a urea-(resin 1:resin 2) compound reaction product, a latent curing agent such as dicyandiamide, mercaptan or acid anhydride, and an epoxy resin that provides low-temperature curing and storage stability, i.e., longer latent curing.

[0086] In another embodiment of the present invention, a one-component 100% solid epoxy composition comprises a urea-(resin 1:resin 2) compound reaction product as a latent curing agent, optionally an accelerator, and an epoxy resin that provides low-temperature curing and storage stability, i.e., longer latent curing.

[0087] In another embodiment of the present invention, a one-component aqueous epoxy composition comprises a urea-(resin 1:resin 2) compound reaction product as a latent curing agent, optionally an accelerator, and an epoxy resin that provides low-temperature curing and storage stability, i.e., longer latent curing.

[0088] The urea-(resin 1:resin 2) compound reaction product of the present invention has been found to cure epoxy resin compositions at low temperatures and can be used as the sole curing agent or accelerator for latent curing agents such as dicyandiamide (DICY), mercaptans, or acid anhydrides in one-component epoxy resin compositions.

[0089] An epoxy composition containing a urea-(resin 1:resin 2) compound reaction product as the sole curing agent or accelerator can provide a long pot life, a low activation temperature, a good glass transition temperature, or a combination of these attributes.

[0090] The term “contact product” is used herein to describe a composition in which components are brought into contact with each other in any order and by any means, over any period of time. For example, components can be brought into contact by compounding or mixing. Furthermore, contact of any component may occur in the presence or absence of any other component of the composition described herein. In addition, when components are brought into contact with each other, two or more components may react to form other components.

[0091] An epoxy composition comprising a urea-(resin 1:resin 2) compound reaction product and an epoxy resin can be formulated with a wide variety of components well known to those skilled in the art of coating formulations, including solvents, fillers, pigments, pigment dispersants, rheology modifiers, thixotropes, flow and leveling aids, and defoamers.

[0092] A one-component epoxy composition can be used, comprising 1 to 90% by weight of an organic solvent, a 100% by weight solids epoxy composition, or an aqueous, water-soluble epoxy composition containing 20 to 80% by weight solids, but the epoxy composition is preferably 100% by weight solids.

[0093] The epoxy compositions of the present invention can be applied as coatings by any number of techniques, including sprays, brushes, rollers, paint mitts, and the like. As is well understood in the art, a number of substrates are suitable for application of the coatings of the present invention with appropriate surface preparation. Such substrates include, but are not limited to, many types of metals, particularly steel and aluminum, as well as concrete.

[0094] The one-component epoxy composition of the present invention can be cured at high temperatures in the range of about 80°C to about 240°C, with a preferred curing temperature of 120°C to 160°C. The two-component epoxy composition of the present invention can be cured at temperatures in the range of about 80°C to about 240°C, with a preferred curing temperature of 80°C to 160°C. [Examples]

[0095] Example 1 208 g of N'-(3-dimethylaminopropyl)-N,N-dimethylpropane-1,3-diamine was placed in a 1 L four-necked glass vessel equipped with a mechanical stirrer, thermocouple, electric heating mantle, addition funnel, reflux condenser, and nitrogen purge. The vessel was heated to 60-70°C under nitrogen. Once the temperature stabilized, 127 g of toluene diisocyanate monomer was slowly weighed in through the addition funnel over 45-60 minutes. After the addition was complete, the mixture was held at 60-80°C for 1 hour. The temperature was raised to 150°C, and 82.5 g of isocryl C-78 acrylic resin was added along with 82.5 g of Arnobol PN320 phenolic resin over 60-90 minutes. After the addition was complete, the mixture was kept at 150°C for another hour with stirring. The product was poured from the reactor at that temperature and cooled to ambient temperature before the product was pulverized.

[0096] Example 2 208 g of N'-(3-dimethylaminopropyl)-N,N-dimethyl-propane-1,3-diamine was placed in a 1 L four-necked glass vessel equipped with a mechanical stirrer, thermocouple, electric heating mantle, addition funnel, reflux condenser, and nitrogen purge. The vessel was heated to 60-70°C under nitrogen. Once the temperature stabilized, 127 g of toluene diisocyanate monomer was slowly weighed in through the addition funnel over 45-60 minutes. After the addition was complete, the mixture was held at 60-80°C for 1 hour. The temperature was raised to 150°C, and 82.5 g of Epomatt G-152 acrylic resin was added along with 82.5 g of Alnovol PN320 phenolic resin over 60-90 minutes. After the addition was complete, the mixture was kept at 150°C for another hour with stirring. The product was poured from the reactor at that temperature and cooled to ambient temperature before the product was pulverized.

[0097] Example 3 208 g of N'-(3-dimethylaminopropyl)-N,N-dimethyl-propane-1,3-diamine was placed in a 1 L four-necked glass vessel equipped with a mechanical stirrer, thermocouple, electric heating mantle, addition funnel, reflux condenser, and nitrogen purge. The vessel was heated to 60-70°C under nitrogen. Once the temperature stabilized, 127 g of toluene diisocyanate monomer was slowly weighed in through the addition funnel over 45-60 minutes. After the addition was complete, the mixture was held at 60-80°C for 1 hour. The temperature was raised to 150°C, and 33 g of Joncryl 67 acrylic resin was added along with 132 g of Alnovol PN320 phenolic resin over 60-90 minutes. After the addition was complete, the mixture was kept at 150°C for another hour with stirring. The product was poured from the reactor at that temperature and cooled to ambient temperature before the product was pulverized.

[0098] Example 4 A mixture of 220.3 g of N'-(3-dimethylaminopropyl)-N,N-dimethyl-propane-1,3-diamine and 50 g of toluene was placed in a 1-liter four-necked glass container equipped with a heating jacket featuring an air-driven mechanical stirrer, thermocouple, water circulation bath, and nitrogen purge. The container was heated to 60-70°C under nitrogen. Once the temperature stabilized, 104.9 g of toluene diisocyanate was weighed into 50 g of toluene over 45-60 minutes. After the addition was complete, the mixture was held at 70°C for 1 hour. The temperature was reduced to 40°C, and the crude liquid product from the reactor was placed in a rotary evaporator to remove all of the toluene. Temperature and vacuum were applied slowly to prevent foaming. The final conditions for distillation were 10-20 mmHg and 80°C, held for 15 minutes. Next, the stripped product was placed in a three-necked flask equipped with a mechanical stirrer, thermocouple, electric heating mantle, and nitrogen purge. The container was stabilized at 140–160°C, and 174.8 g of phenolic resin was added over 30–60 minutes. The mixture was maintained at 160°C and allowed to stand for another hour. The product was then poured from the reactor and cooled to ambient temperature before grinding.

[0099] Example 5 - Differential scanning calorimetry (DSC) of urea-curable resin blocks The reaction products of Examples 1-4 were screened by differential scanning calorimeter (DSC) for their curing profiles as epoxy curing agents. The epoxy formulations contained polyglycidyl ether of bisphenol A resin (Epon 828), 2 phr (parts by weight per 100 parts by weight of resin) of Examples 1-4 as accelerators, 6 phr of dicyandiamide as curing agents, and 2 wt% fumed silica as curing agents. The resulting mixtures were thoroughly blended for 2 minutes using a speed mixer. Immediately after preparation, the mixtures were analyzed by DSC (TA instrument QA20) to determine the curing onset temperature, reaction heat (ΔH), and glass transition temperature (Tg). The DSC was operated according to standard procedures using the software included with the DSC. DSC analysis was performed using a ramp thermal rate of 10°C / min for approximately 10-15 mg of material samples. The obtained data are shown in Table 1 below. [Table 1]

[0100] Example 6: Latency of urea-curable resin block The potential of Examples 1-4 as DICY accelerators was tested at 40°C using an epoxy formulation containing 2 phr of polyglycidyl ether of bisphenol A resin (Epon 828) as an accelerator, 6 phr of dicyandiamide as a curing agent, and 2 wt% fumed silica. Using 0.5 mL samples, the potential was monitored as the viscosity change during aging at 40°C using a Brookfield Cone and Plate viscometer (Model HADV II+CP) with a #52 spindle at 25°C. Storage stability was determined by visual observation to determine the gelation time. Fresh epoxy samples were thoroughly blended for 2 minutes using a speed mixer, cooled to 25°C, and the initial viscosity was measured using a Brookfield Cone and Plate viscometer. The samples were stored in an oven at 40°C, cooled to 25°C, and the viscosity change was measured over time. The obtained data are shown in Table 2. [Table 2]

[0101] Example 7: Adhesion characteristics The adhesive properties of the urea-curable resin block were measured by lap shear strength and T-type peel technique. Lap shear strength measurements were performed at least five times in an Instron Model 1125 apparatus according to ASTM method D1876. The test material was applied to a 1-inch x 0.4-inch x 0.32-inch cold-rolled steel panel (ACT cold-rolled steel 01X04X032 B952 P60DIW: unpolished). The material was applied to the 1 / 2-inch end of a coupon using 10 mil glass beads (1% based on the compound weight). Another coupon was placed so as to overlap the 1 / 2-inch strip of the other coupon. The panel containing the test material was cured at a temperature of 130°C to 160°C for 15 to 30 minutes, and then cooled to room temperature before measurement.

[0102] T-type delamination was measured at least five times in an Instron Model 1125 apparatus according to the ASTM method D1876 for lap shear strength. The test material was applied to a 1-inch x 4-inch x 0.32-inch cold-rolled steel panel (ACT cold-rolled steel 01X04X032 B952 P60DIW: unpolished) that had been pre-bent 7 / 8 inches perpendicularly from the edge, leaving a 3 1 / 8-inch x 1-inch surface. The material was applied using 10 mil glass beads (1% based on the weight of the mixture). The test material was cured at a temperature of 130°C to 160°C for 15 to 30 minutes, and then cooled to room temperature before measurement. The results of the lap shear strength and T-type delamination measurements are shown in Table 3 below: [Table 3]

[0103] While the present invention has been described with reference to specific aspects or embodiments, those skilled in the art will understand that various modifications can be made and elements can be replaced with equivalents without departing from the scope of the invention. Furthermore, many modifications can be made to adapt the teachings of the invention to specific situations or materials without departing from the essential scope of the invention. Thus, the invention is not limited to the specific aspects or embodiments disclosed as the best mode intended for carrying out the invention, and the invention is intended to include all embodiments that fall within the scope of the appended claims, including the use of aspects or embodiments of the invention individually or in combination with each other.

Claims

1. Urea compounds and, Polyphenol resin and An additional excipient selected from functional and / or non-functional components, Including mounting media systems, Latent curing accelerator composition.

2. The composition according to claim 1, wherein the polyphenol resin is a phenol novolac resin.

3. The composition according to claim 2, wherein the phenol novolac resin is a phenol-formaldehyde resin.

4. Urea compounds and, An additional excipient selected from functional and / or non-functional components, Including mounting media systems, Latent curing accelerator composition.

5. The composition according to any one of claims 1 to 4, wherein the urea compound comprises a reaction product of an isocyanate and an alkylated polyalkylene polyamine.

6. The composition according to any one of claims 1 to 5, wherein the isocyanate is selected from the group consisting of aliphatic isocyanates, alicyclic isocyanates, and aromatic isocyanates.

7. The composition according to claim 6, wherein the isocyanate is selected from the group consisting of phenyl isocyanate, toluene diisocyanate (TDI), methylenediphenyl diisocyanate (MDI), and polymer methylenediphenyl diisocyanate.

8. The alkylated polyalkylene polyamine comprises at least one primary or secondary amine and formula (A): 【Chemistry 1】 (In the formula, R １ , R ２ , R ３ , R ４ and R ５ The composition according to any one of claims 5 to 7, wherein is independently hydrogen, methyl, or ethyl, m and n are independently integers from 1 to 6, and X is an integer from 1 to 10.

9. R １ is hydrogen or methyl, R ２ and R ４ are methyl, R ３ and R ５ is hydrogen or methyl, the composition according to claim 8.

10. The composition according to any one of claims 1 to 9, wherein the additional excipient is a functional polymer compound.

11. The composition according to any one of claims 1 to 10, wherein the additional excipient is selected from polyamide resin, polybutadiene resin, polyester resin, polyether resin, and acrylic resin.

12. The composition according to any one of claims 1 to 11, wherein the additional excipient is the acrylic resin.

13. The composition according to any one of claims 1 to 12, wherein a curable epoxy system is formed by combining it with an epoxy resin, and the curable epoxy system does not gel after 4 weeks under accelerated degradation conditions (i.e., storage at 40°C for 4 weeks).

14. The composition according to any one of claims 1 to 13, wherein a curable epoxy system is formed by combining it with an epoxy resin, and the curable epoxy system has a lap shear strength of more than 700 psi.

15. A method for curing a substance by using the latent curing accelerator composition according to any one of claims 1 to 14, wherein the method comprises the step of combining the substance with the latent curing accelerator composition and heating the resulting mixture.

16. The method according to claim 15, wherein the substance is an epoxy resin.

17. The method according to claim 15 or 16, wherein the composition is a latent curing agent for epoxy resins (e.g., a sole latent curing agent), or the composition is used as an accelerator for curing agents such as DICY or for acid anhydrides for epoxy resins.

18. The method according to any one of claims 15 to 17, wherein the composition is used as a latent curing accelerator for structural adhesives and composites, electropotting and encapsulation, reinforcement and / or damping, in-situ curing pipes, impact adhesives, filament winding, transfer molding powder, prepregs containing solid or liquid epoxy, sheet molding compounds, coatings for concrete, wood, metal, etc., resin transfer molding, and / or battery pack adhesives.

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