EP3924413A1 - Adhésifs structuraux syntactiques époxy de faible densité pour des applications automobiles - Google Patents

Adhésifs structuraux syntactiques époxy de faible densité pour des applications automobiles

Info

Publication number
EP3924413A1
EP3924413A1 EP19909618.1A EP19909618A EP3924413A1 EP 3924413 A1 EP3924413 A1 EP 3924413A1 EP 19909618 A EP19909618 A EP 19909618A EP 3924413 A1 EP3924413 A1 EP 3924413A1
Authority
EP
European Patent Office
Prior art keywords
structural adhesive
syntactic structural
syntactic
epoxy resin
low density
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19909618.1A
Other languages
German (de)
English (en)
Inventor
Wenfeng Kuang
Rui Xie
Jose TREVINO III
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huntsman Advanced Materials Americas LLC
Original Assignee
Huntsman Advanced Materials Americas LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huntsman Advanced Materials Americas LLC filed Critical Huntsman Advanced Materials Americas LLC
Publication of EP3924413A1 publication Critical patent/EP3924413A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J163/00—Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
    • C08G59/20—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the epoxy compounds used
    • C08G59/32—Epoxy compounds containing three or more epoxy groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
    • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
    • C08G59/42—Polycarboxylic acids; Anhydrides, halides or low molecular weight esters thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
    • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
    • C08G59/50—Amines
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/32—Phosphorus-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/49—Phosphorus-containing compounds
    • C08K5/51—Phosphorus bound to oxygen
    • C08K5/52—Phosphorus bound to oxygen only
    • C08K5/521—Esters of phosphoric acids, e.g. of H3PO4
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/04—Non-macromolecular additives inorganic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/52—Encapsulations
    • H01L33/56—Materials, e.g. epoxy or silicone resin
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K2003/026—Phosphorus
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/354—Applications of adhesives in processes or use of adhesives in the form of films or foils for automotive applications

Definitions

  • the present disclosure generally relates to a syntactic structural adhesive comprising an epoxy resin, a low density particulate filler and a hardener.
  • the syntactic structural adhesive is particularly useful in automotive applications for bonding and/or sealing metal, plastic and composite parts.
  • the structural adhesives that have replaced or augmented metal fasteners and/or welds during automotive assembly are generally based on epoxy resins, polyurethanes and acrylic resins.
  • epoxy resins polyurethanes
  • acrylic resins acrylic resins
  • WO 2016/108958 discloses a one-component structural adhesive comprising an epoxy resin, a polyurethane based toughener, at least one amphipathic block copolymer and one or more curing agents. This structural adhesive is taught to exhibit improved impact resistance at low temperatures;
  • U.S. Pat. No. 9,534,072 discloses a structural adhesive prepared from the reaction of an organic polyisocyanate with a compound containing isocyanate-reactive hydrogen atoms in the presence of a trimerization catalyst. This structural adhesive is taught to exhibit good adhesion in more severe climate conditions, such as at elevated temperature or in salty conditions;
  • WO 2015/164031 discloses a two-component structural adhesive comprising an acrylate polyurethane, an epoxy resin, a polythiol and a polyamine. This structural adhesive is taught to exhibit reduced read-through;
  • US 2014/0147677 discloses a structural adhesive comprising an epoxy resin and a hardener where the hardener is present in an amount of about equal to or less than the stoichiometric amount relative to the epoxy resin.
  • This structural adhesive is taught to have good humidity resistance, failure mode after curing, crash stability and corrosion resistance;
  • US 2011/0024039 and U.S. Pat. No. 8,618,204 disclose one-component and two-component structural adhesives generally comprising an epoxy resin, a curing agent and a reactive liquid modifier or oil displacing agent. These structural adhesives are taught to exhibit good adherence to clean surfaces as well as to surfaces contaminated with hydrocarbon-containing material;
  • WO 2007/143646 discloses a structural adhesive comprising an epoxy resin, a polyester, a blowing agent and a curing agent.
  • the structural adhesive is taught to exhibit good corrosion resistance due to the presence of the polyester;
  • US 2007/0155879 discloses a two-component structural adhesive comprising a vinyl monomer, a soluble polymer and an acetylenic diol adhesion promoter. This structural adhesive is taught to exhibit an improvement in the ability to bond to a variety of metals.
  • an automotive structural adhesive could be developed having a reduced density without a reduction in mechanical performance, it could allow electric vehicles to reach travel ranges of, for example 400 miles or more/charge, which is similar to those for gasoline-powered vehicles.
  • the present disclosure generally provides a syntactic structural adhesive comprising (a) an epoxy resin, (b) a low density particulate filler, and (c) a hardener where the syntactic structural adhesive, upon curing, exhibits at least the following well-balanced properties: (i) a density less than 1 g/cm 3 ; (ii) a compression modulus greater than 500 MPa; and (iii) a lap shear strength greater than 750 psi.
  • the present disclosure also provides a method of forming a bonded joint between two substrates by providing the syntactic structural adhesive, applying the syntactic structural adhesive to a surface of at least one of the two substrates, joining the two substrates so that the syntactic structural adhesive is sandwiched between the two substrates and curing the syntactic structural adhesive to form a bonded joint between the two substrates.
  • the syntactic structural adhesive may be used as a structural adhesive in a variety of applications, such as in vehicle assembly including, but not limited to, the assembly of: watercraft vehicles; aircraft vehicles; railway vehicles; motorcraft vehicles, such as cars and motorcycles; and bicycles.
  • the present disclosure generally provides a syntactic structural adhesive comprising (a) an epoxy resin, (b) a low density particulate filler, and (c) a hardener. It has been surprisingly found when particular low density particulate fillers are combined with the epoxy resin and hardener and cured, the cured syntactic structural adhesive of the present disclosure exhibits a density that is 30%-60% less than conventional structural adhesives currently used in automotive bonding applications while also exhibiting similar, if not improved, mechanical properties and chemical properties, such as compression modulus, lap shear strength, adhesion to a number of substrates, temperature resistance and flame retardation. Accordingly, the syntactic structural adhesive of the present disclosure unexpectedly exhibits an excellent balance of physical, mechanical and thermal properties as compared to those for state of the art structural adhesives.
  • structural adhesive refers to an adhesive which is capable of bonding substrates together by surface attachment (i.e., the adhesive in the cured state forms a portion of the bearing structure of the bonded substrates).
  • the structural adhesive of the present disclosure encompasses a one-component adhesive and a multi-component adhesive, for example, a two-component adhesive.
  • low density particulate filler means a particulate filler having an average bulk density less than about 0.6 g/cm 3 , for example between 0.01 g/cm 3 - 0.5 g/cm 3 , or between 0.1 g/cm 3 - 0.4 g/cm 3 .
  • high density particulate filler means a particulate filler having an average bulk density of at least 1.5 g/cm 3 , or at least 2.0 g/cm 3 or even at least 2.5 g/cm 3 .
  • curing refers to subjecting the syntactic structural adhesive to curing conditions, such as, but not limited to, thermal curing, leading to the reaction of the reactive functional groups of the adhesive and resulting in polymerization and formation of a polymerizate.
  • curing conditions such as, but not limited to, thermal curing, leading to the reaction of the reactive functional groups of the adhesive and resulting in polymerization and formation of a polymerizate.
  • the syntactic structural adhesive can be subjected to curing conditions until it is at least partially cured.
  • the term“at least partially cured” means subjecting the syntactic structural adhesive to curing conditions, wherein reaction of at least a portion of the reactive groups of the adhesive occurs to form a polymerizate.
  • the syntactic structural adhesive can also be subjected to curing conditions such that a substantially complete cure is attained and wherein further curing results in no significant further improvement in polymer properties, such as compressive strength.
  • reactive refers to a functional group capable of undergoing a chemical reaction with other functional groups spontaneously or upon the application of heat or by any other means known to those skilled in the art.
  • syntactic structural adhesive“applied onto” a substrate does not preclude the presence of one or more other intervening coating layers of the same or different composition located between the syntactic structural adhesive and the substrate.
  • substantially free means, when used with reference to the substantial absence of a material in an adhesive formulation, that such a material is not present, or if present is an incidental impurity or by-product. In other words, the material does not affect the properties of the adhesive formulation.
  • compositions claimed herein through use of the term“comprising” may include any additional additive or compound, unless stated to the contrary.
  • the term,“consisting essentially of’ if appearing herein excludes from the scope of any succeeding recitation any other component, step or procedure, excepting those that are not essential to operability and the term“consisting of’, if used, excludes any component, step or procedure not specifically delineated or listed.
  • an epoxy resin means one epoxy resin or more than one epoxy resin.
  • phrases“in one aspect”,“according to one aspect” and the like generally mean the particular feature, structure, or characteristic following the phrase is included in at least one aspect of the present disclosure, and may be included in more than one aspect of the present disclosure. Importantly, such phrases do not necessarily refer to the same aspect.
  • the present disclosure provides a syntactic structural adhesive comprising (a) an epoxy resin (b) a low density particulate filler and (c) a hardener where a resultant cured product formed by curing the syntactic structural adhesive contains at least the following well-balanced properties: (1) a density of less than 1.0 g/cm 3 ; (2) a lap shear strength greater than 1000 psi; and (3) a compression modulus greater than 750 MPa.
  • any epoxy-containing compound is suitable for use as the epoxy resin in the present disclosure, such as the epoxy-containing compounds disclosed in U.S. Pat. Nos. 5,476,748; 6,506,494; 6,632,893; 6,376,564; 6,348,513; 8,742,018; and 8,440,746, which are incorporated herein by reference.
  • the epoxy resin may be solid or liquid and has at least one oxirane ring that is polymerizable by ring opening, i.e., an average epoxy functionality greater than one, and in some aspects at least two.
  • the epoxy resin can be monomeric or polymeric, and aliphatic, cycloaliphatic, heterocyclic, aromatic, hydrogenated, or mixtures thereof. In some aspects, the epoxy resin contains more than 1.5 epoxy groups per molecule and preferably at least 2 epoxy groups per molecule.
  • the epoxy resin may have a weight average molecular weight of about 150 to about 10,000 or about 180 to about 1,000.
  • the molecular weight of the epoxy resin may also be selected to provide the desired properties of the cured adhesive.
  • the epoxy resin may be a polyglycidyl epoxy compound.
  • the polyglycidyl epoxy compound may be a polyglycidyl ether, ro1g(b- methylglycidyl) ether, polyglycidyl ester or pol y (b -m eth y 1 gl y ci dy 1 ) ester.
  • the synthesis and examples of polyglycidyl ethers, poly ⁇ -methylglycidyl) ethers, polyglycidyl esters and poly ⁇ -methylglycidyl) esters are disclosed in U.S. Pat. No. 5,972,563 which is incorporated herein by reference.
  • ethers may be obtained by reacting a compound having at least one free alcoholic hydroxyl group and/or phenolic hydroxyl group with a suitably substituted epichlorohydrin under alkaline conditions or in the presence of an acidic catalyst followed by alkali treatment.
  • the alcohols may be, for example, acyclic alcohols, such as ethylene glycol, diethylene glycol and higher poly(oxyethylene) glycols, propane- 1,2-diol, or poly(oxypropylene) glycols, propane-1, 3-diol, butane- 1,4-diol, poly(oxytetram ethylene) glycols, pentane- 1, 5-diol, hexane-1, 6-diol, hexane-2, 4, 6-triol, glycerol, 1, 1,1-trimethylolpropane, bistrimethylolpropane, pentaerythritol and sorbitol.
  • acyclic alcohols such as ethylene glycol, diethylene glycol and higher poly(oxyethylene) glycols, propane- 1,2-diol, or poly(oxypropylene) glycols, propane-1, 3-diol, butane- 1,4-diol, poly(oxytetram
  • Suitable glycidyl ethers may also be obtained, however, from cycloaliphatic alcohols, such as 1,3- or 1,4- dihydroxycyclohexane, bis(4-hydroxycyclo-hexyl)methane, 2,2-bis(4- hydroxycyclohexyl)propane or l,l-bis(hydroxymethyl)cyclohex-3-ene, or they may possess aromatic rings, such as N,N-bis(2-hydroxyethyl)aniline or p,p’-bis(2- hydroxyethylamino)diphenylmethane.
  • cycloaliphatic alcohols such as 1,3- or 1,4- dihydroxycyclohexane, bis(4-hydroxycyclo-hexyl)methane, 2,2-bis(4- hydroxycyclohexyl)propane or l,l-bis(hydroxymethyl)cyclohex-3-ene, or they may possess aromatic rings, such as N,N-bis(2-hydroxyeth
  • Particularly important representatives of polyglycidyl ethers or ro1g(b- methylglycidyl)ethers are based on monocyclic phenols, for example, on resorcinol or hydroquinone, on polycyclic phenols, for example, on bis(4-hydroxyphenyl)methane (Bisphenol F), 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A), bis(4- hydroxyphenyl)sulfone (Bisphenol S), alkoxylated Bisphenol A, F or S, triol extended Bisphenol A, F or S, brominated Bisphenol A, F or S, hydrogenated Bisphenol A, F or S, glycidyl ethers of phenols and phenols with pendant groups or chains, on condensation products, obtained under acidic conditions, of phenols or cresols with formaldehyde, such as bisphenol A novolaks and cresol novolaks, or on siloxane diglycidyl
  • the polycarboxylic acid compounds may be, for example, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid or dimerized or trimerized linoleic acid.
  • cycloaliphatic polycarboxylic acids for example tetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid or 4-methylhexahydrophthalic acid.
  • aromatic polycarboxylic acids such as, for example, phthalic acid, isophthalic acid, trimellitic acid or pyromellitic acid, or else carboxyl-terminated adducts, for example of trimellitic acid and polyols, for example glycerol or 2,2-bis(4- hydroxycyclohexyl)propane, may be used.
  • the epoxy resin may be a non-glycidyl epoxy compound.
  • Non-glycidyl epoxy compounds may be linear, branched, or cyclic in structure.
  • Others include an epoxy-containing compound with at least one epoxycyclohexyl group that is bonded directly or indirectly to a group containing at least one silicon atom. Examples are disclosed in U.S. Pat. No. 5,639,413, which is incorporated herein by reference.
  • Still others include epoxides which contain one or more cyclohexene oxide groups and epoxides which contain one or more cyclopentene oxide groups.
  • non-glycidyl epoxy compounds include the following: difunctional non-glycidyl epoxide compounds in which the epoxide groups form part of an alicyclic or heterocyclic ring system: bis(2,3-epoxycyclopentyl)ether, l,2-bis(2,3-epoxycyclopentyloxy)ethane, 3, 4-epoxy cyclohexyl-methyl 3,4- epoxycyclohexanecarboxylate, 3,4-epoxy-6-methyl-cyclohexylmethyl 3,4-epoxy-6- methylcyclohexanecarboxylate, di(3, 4-epoxy cy cl ohexylmethyl)hexanedioate, di(3,4- epoxy-6-methylcyclohexylmethyl) hexanedioate, ethylenebis(3,4- epoxycyclohexanecarboxylate) and ethanediol di(3, 4-
  • the difunctional non-glycidyl epoxy compounds include cycloaliphatic difunctional non-glycidyl epoxies, such as 3,4- epoxycyclohexyl-methyl 3’,4’-epoxycyclohexanecarboxylate and 2,2’-bis-(3,4-epoxy- cyclohexyl)-propane, with the former being most preferred.
  • cycloaliphatic difunctional non-glycidyl epoxies such as 3,4- epoxycyclohexyl-methyl 3’,4’-epoxycyclohexanecarboxylate and 2,2’-bis-(3,4-epoxy- cyclohexyl)-propane, with the former being most preferred.
  • the epoxy resin may be a poly(N-glycidyl) compound or poly(S-glycidyl) compound.
  • Poly(N-glycidyl) compounds are obtainable, for example, by dehydrochlorination of the reaction products of epichlorohydrin with amines containing at least two amine hydrogen atoms. These amines may be, for example, n-butylamine, aniline, toluidine, m-xylylenediamine, bis(4-aminophenyl)methane or bis(4-methylaminophenyl)methane.
  • poly(N-glycidyl) compounds include N,N’-diglycidyl derivatives of cycloalkyleneureas, such as ethyleneurea or 1, 3 -propyl eneurea, and N,N’-diglycidyl derivatives of hydantoins, such as of 5,5-dimethylhydantoin.
  • poly(S- glycidyl) compounds are di-S-glycidyl derivatives derived from dithiols, for example ethane- 1,2-dithiol or bis(4-mercaptomethylphenyl)ether.
  • epoxy resins in which the 1,2-epoxide groups are attached to different heteroatoms or functional groups.
  • examples include the N,N,O-triglycidyl derivative of 4-aminophenol, the glycidyl ether/glycidyl ester of salicylic acid, N-glycidyl-N’-(2-glycidyloxypropyl)-5,5-dimethylhydantoin or 2- glycidyloxy-l,3-bis(5,5-dimethyl-l-glycidylhydantoin-3-yl)propane.
  • epoxide derivatives may also be employed, such as vinyl cyclohexene dioxide, limonene dioxide, limonene monoxide, vinyl cyclohexene monoxide, 3, 4-epoxy cy cl ohexlmethyl acrylate, 3,4-epoxy-6-methyl cyclohexylmethyl 9, 10-epoxystearate, and l,2-bis(2,3-epoxy-2-methylpropoxy)ethane.
  • the epoxy resin may be a pre-reacted adduct of an epoxy resin, such as those mentioned above, with compounds having a free hydrogen that is reactive with an epoxy group. Typically, such reactive hydrogens are found in carboxylic acid groups, aromatic hydroxyl groups, amino groups, and sulfhydryl groups.
  • the syntactic structural adhesive may contain only one epoxy resin while in other aspects, the syntactic structural adhesive may contain a mixture of epoxy resins.
  • the epoxy resin comprises at least one multifunctional epoxy resin.
  • the multifunctional epoxy resin may be a difunctional epoxy resin, a trifunctional epoxy resin, a tetrafunctional epoxy resin or a mixture thereof.
  • difunctional epoxy resins include, but are not limited to, diglycidyl ethers of bisphenol A-based materials (e.g., EponTM 828 epoxy resin, D.E.R.TM 331 and D.E.R.TM 661 epoxy resins, Tactix® 123 epoxy resin, and Araldite® 184 epoxy resin).
  • diglycidyl ethers of bisphenol A-based materials e.g., EponTM 828 epoxy resin, D.E.R.TM 331 and D.E.R.TM 661 epoxy resins, Tactix® 123 epoxy resin, and Araldite® 184 epoxy resin.
  • trifunctional epoxy resins include, but are not limited to, triglycidyl ether of aminophenol, (e.g., Araldite® MY 0510, MY 0500, MY 0600 and MY 0610 epoxy resins).
  • tetrafunctional epoxy resins include, but are not limited to, tetraglycidyl ether of methylene dianiline (e.g., Araldite® MY 9655 epoxy resin), tetraglycidyl diaminodiphenyl methane (e.g., Araldite® MY-721, MY-720, 725, MY 9663, 9634 and 9655 epoxy resins) and sorbitol polyglycidyl ether (e.g., EJ-190 epoxy resin and ERISYS® GE-60 epoxy resin).
  • tetraglycidyl ether of methylene dianiline e.g., Araldite® MY 9655 epoxy resin
  • tetraglycidyl diaminodiphenyl methane e.g., Araldite® MY-721, MY-720, 725, MY 9663, 9634 and 9655 epoxy resins
  • the epoxy resin may be comprised of at least one multifunctional epoxy resin together with at least one monofunctional epoxy resin.
  • monofunctional epoxy resins include, but are not limited to, phenyl glycidyl ether, cresyl glycidyl ether, para-t-butyl phenyl glycidyl ether, C6-C28 alkyl glycidyl ethers, C6-C28 fatty acid glycidyl esters and C6-C28 alkylphenol glycidyl ethers.
  • the amount of epoxy resin used in the syntactic structural adhesive may depend on the targeted molecular weight and epoxy functionality.
  • the syntactic structural adhesive may include the epoxy resin in an amount of from about 10 wt.% to about 90 wt.%, based on the total weight of the syntactic structural adhesive.
  • the syntactic structural adhesive may include the epoxy resin in an amount of from about 12.5 wt.% by weight to about 75 wt.%, or from about 15 wt.% to about 60 wt.%, or from about 17.5 wt.% to about 50 wt.%, or even from about 20 wt.% to about 40 wt.%, where the % by weight is based on the total weight of the syntactic structural adhesive.
  • the syntactic structural adhesive also contains a low density particulate filler.
  • the low density particulate filler includes, but is not limited to, a naturally occurring mineral, a manmade material, silica particles, a lightweight waste product and mixtures thereof.
  • fillers generally include, but are not limited to, pearlite, vermiculite, hollow microspheres and microballons made from glass, ceramics, carbon, metal or synthetic resins, fumed silica, colloidal silicas, precipitated silicas, silica gels, ground up tires, ground up wood fibers, ground up cellulose fibers and ground up polymer foams made from a variety of different polymers including polyesters, polyamides, polystyrenes, polyurethanes and polyisocyanurates.
  • the low density particulate filler may include irregularly shaped particles or spherically shaped particles or mixtures thereof.
  • Irregularly shaped particles include particles which lack a uniform spherical or platelet shape. Irregularly shaped particles are typically obtained through precipitation, grinding or pulverizing, or are comprised of fused or aggregated primary particles, to yield particles with irregular shape or surface texture. The irregularly shaped particles, in general, have a particle size of less than about 300 pm, and even less than about 100 pm.
  • Spherical particles have or substantially have the shape of a sphere and may be hollow or solid.
  • the spherical particles in general, have a particle size of less than about 300 pm, and even less than about 100 pm.
  • the low density particulate filler includes spherical hollow particles, such as for example hollow inorganic particles or hollow organic particles, for example inorganic microspheres or organic microspheres, or combinations thereof.
  • the hollow part of the particles may be filled by a gas or mixture of gases, a liquid or mixture of liquids, or a mixture of one or more gases and one or more liquids, or may be a vacuum.
  • the inorganic microspheres may be selected from a variety of materials including by way of example glass, silica, ceramic (including sol-gel derived), zirconia and combinations thereof.
  • the inorganic particles may comprise silica, a soda-lime borosilicate glass, a silica-alumina ceramic, an alkali alumino silicate ceramic type, aluminum oxide or combinations thereof.
  • the inorganic microspheres may be selected so that they allow the cured syntactic structural adhesive to exhibit low density without compromising compressive strength.
  • the inorganic microspheres will have a density of less than 0.5 g/cm 3 and at least 85 wt.% and even at least 90 wt.% of the inorganic microspheres have a collapse strength of at least 2500 psi or at least 4000 psi, where the wt.% is based on the total weight of the inorganic microspheres.
  • the average particle size for the inorganic microspheres may range from between about 1 pm to about 300 pm, or from between about 10 pm to about 100 pm.
  • the inorganic microspheres are glass microspheres or microbubbles such as those described in U.S. Pat. No.
  • microspheres are made by expanding solid glass particles at temperatures above 1000°C to form tiny hollow spheroids having an apparent density in the range of about 0.14 to about 0.38 g/cm 3 , a wall thickness of about 0.5 to 2.0 microns, and an average particle size of about 60 microns.
  • Other glassy or inorganic microspheres of synthetic fused water-insoluble alkali metal silicate-based glass which may be used are described in U.S. Pat. No. 3,230,184, and microspheres made of sodium silicate which are useful in the present disclosure are described in U.S. Pat. No. 3,030,215, the contents of which are incorporated herein by reference.
  • Microspheres prepared from heat expanded natural minerals such as perlite, volcanic ash, fly ash and vermiculite may also be used.
  • Commercially available inorganic microspheres include those under the trade designation ScotchliteTM glass bubbles, Q-CEL® inorganic microspheres and EXTENDOSPHERES® ceramic microspheres.
  • Organic microspheres include polymeric microspheres made of organic polymers, i.e., materials comprising repeating units derived from monomers containing at least one unsaturated carbon-carbon bond.
  • Typical examples of such polymers include, but are not limited to, acrylonitrile polymers or copolymers, acrylate polymers or copolymers, vinylidene polymers or copolymers, polyacetate polymers or copolymers, polyester polymers or copolymers, vinylidenechloride/acrylonitrile copolymers, acrylate/acrylonitrile copolymers and combinations thereof.
  • the organic microspheres may be unexpanded or preexpanded organic hollow microspheres.
  • Unexpanded organic hollow microspheres sometimes referred to as expandable organic microballoons, are available, for example, under the trade designations EXPANCEL® and MICROPEARL® microspheres.
  • Such microspheres comprise a thermoplastic shell entrapping a volatile liquid, such as a hydrocarbon (e.g., ethane, ethylene, propane, propene, butane, isobutane, neopentane, acetylene, hexane, heptane and isopentane), a chlorofluorocarbon, a tetraalkyl silane (e.g., tetramethyl silane, trimethylethyl silane, trimethylisopropyl silane, and trimethyl n-propyl silane) as well as perfluorocarbons.
  • a volatile liquid such as a hydrocarbon (e.g., ethane, ethylene, propane, propene, butane, isobutane, neopentane, acetylene, hexane, heptane and isopentane), a chlorofluorocarbon, a tetraalkyl
  • the thermoplastic shell may include, but is not limited to, polyvinylidene-polyacrylonitrile, polyvinylidene- polyacrylonitrile-polymethylmethacrylate, and polystyrene-polyacrylonitrile copolymers.
  • Preexpanded organic microspheres are previously expanded through the use of an organic blowing agent (e.g., a hydrocarbon such as described above including pentane, isopentane, butane, or mixtures of these) or an inorganic blowing agent (e.g., air, carbon dioxide, nitrogen, argon, or mixtures of these) to provide a particle having a larger size but a lower density.
  • an organic blowing agent e.g., a hydrocarbon such as described above including pentane, isopentane, butane, or mixtures of these
  • an inorganic blowing agent e.g., air, carbon dioxide, nitrogen, argon, or mixtures of these
  • the preexpanded organic microspheres can be comprised of from 1% to 99%, 25% to 95% or 50% to 90% air by volume.
  • the preexpanded microspheres can be partially expanded (i.e., capable of further expansion) or fully expanded.
  • the microspheres can be greater than 50%
  • the preexpanded organic microspheres described herein can be derived from expandable polymers, including, for example, thermoplastic polymers.
  • expandable polymers including, for example, thermoplastic polymers.
  • examples include polystyrene (e.g., free-radical-polymerized glass-clear polystyrene (GPPS) or anionically polymerized polystyrene (APS)), styrene-based-copolymers (e.g., styrene- maleic anhydride copolymers, styrene-butadiene copolymers, styrene-a-m ethyl styrene copolymers, acrylonitrile-butadiene-styrene (ABS) copolymers, styrene-acrylonitrile (SAN) copolymers, styrene-methyl methacrylate copolymers, acrylonitrile-styren
  • suitable preexpanded microspheres include those derived from polyphenylene oxide, polystyrene-polyphenylene oxide blends, polyoxymethylene, poly(methyl methacrylate), methyl methacrylate copolymers, ethylene-propylene copolymers (e.g., random and block), ethylene-vinyl acetate copolymers, polycarbonate, polyethylene terephthalate, aromatic polyester/polyether glycol block copolymer, polyethylene and polymerized vinyl aromatic resins.
  • vinyl aromatic resins include the solid homopolymers of styrene, vinyltoluene, vinylxylene, ethylvinylbenzene, isopropyl styrene, t-butyl styrene, chlorostyrene, dichlorostyrene, fluorostyrene, bromostyrene; the solid copolymers of two or more monovinyl aromatic compounds, and the solid copolymers of one or more of monovinyl aromatic compounds and a copolymerizable olefmic compound (e.g., acrylonitrile, methyl methacrylate, or ethyl acrylate).
  • a copolymerizable olefmic compound e.g., acrylonitrile, methyl methacrylate, or ethyl acrylate
  • Such preexpanded organic microspheres are commercially available, for example, under the trade designation DUALITE® microspheres, GRAFGUARD® expandable graphite particles and STYROPOR® microspheres.
  • DUALITE® microspheres GRAFGUARD® expandable graphite particles
  • STYROPOR® microspheres STYROPOR® microspheres.
  • the concentration and the nature of the low density particulate fillers for use in the syntactic structural adhesive may be selected such that the density of the syntactic structural adhesive is less than 1 g/cm 3 , or less than 0.8 g/cm 3 , or even between about 0.5 g/cm 3 and 0.75 g/cm 3 or still even between about 0.55 g/cm 3 and 0.65 g/cm 3 .
  • the syntactic structural adhesive of the present disclosure may contain from about 1 wt.% to about 80 wt.%, or from about 2 wt.% to about 60 wt.%, or from about 5 wt.% to about 50 wt.%, or from about 7.5 wt.% to about 45 wt.%, or from about 10 wt.% to about 40 wt.%, or even from about 15 wt.% to about 30 wt.% of the low density particulate filler, based on the total weight of the syntactic structural adhesive.
  • hardening of the syntactic structural adhesive may be accomplished by the addition of any chemical material(s) known in the art for curing such adhesives.
  • materials are compounds that have a reactive moiety that can react with the epoxy group of the epoxy resin and are referred to herein as“hardeners” but also include the materials known to those skilled in the art as curing agents, curatives, activators, catalysts or accelerators. While certain hardeners promote curing by catalytic action, others participate directly in the reaction of the resin and are incorporated into the thermoplastic polymeric network formed by condensation, chain- extension and/or cross-linking of the resin. Depending on the hardener, heat may or may not be required for significant reaction to occur.
  • Hardeners for the epoxy resin include, but are not limited to aromatic amines, cyclic amines, aliphatic amines, alkyl amines, polyether amines, including those polyether amines that can be derived from polypropylene oxide and/or polyethylene oxide, acid anhydrides, carboxylic acid amides, polyamides, polyphenols, cresol and phenol novolac resins, imidazoles, guanidines, substituted guanidines, substituted ureas, melamine resins, guanamine derivatives, tertiary amines, Lewis acid complexes, such as boron trifluoride and boron trichloride and polymercaptans. Any epoxy-modified amine products, Mannich modified products, and Michael modified addition products of the hardeners described above may also be used. All of the above mentioned curatives may be used either alone or in any combination.
  • the hardener is a multifunctional amine.
  • the term“multifunctional amine” as used herein refers to an amine having at least two primary and/or secondary amino groups in a molecule.
  • the multifunctional amine may be an aromatic multifunctional amine having two amino groups bonded to benzene at any one of ortho, meta and para positional relations, such as phenylenediamine, xylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene and 3,5-diaminobenzoic acid, an aliphatic multifunctional amine such as ethyl enediamine and propyl enediamine, an alicyclic multifunctional amine such as 1,2- diaminocyclohexane, 1,4-diaminocyclohexane, piperazine, 1,3-bispiperidylpropane and 4-aminomethylpiperazine, and the like.
  • These multifunctional amines may be
  • Exemplary aromatic amines include, but are not limited to 1,8 diaminonaphthalene, m-phenylenediamine, diethylene toluene diamine, diaminodiphenylsulfone, diaminodiphenylmethane, diaminodiethyldimethyl diphenylmethane, 4,4'-methylenebis(2,6-diethylaniline), 4,4'-m ethyl enebis(2- isopropyl-6-methylaniline), 4,4'-methylenebis(2,6-diisopropylaniline), 4,4'-[l,4- phenylenebis(l-methyl-ethylindene)]bisaniline, 4, 4'-[l, 3-phenyl enebis(l -methyl - ethylindene)]bisaniline, l,3-bis(3-aminophenoxy)benzene, bis-[4-(3- aminophenoxy)
  • cyclic amines include, but are not limited to bis(4-amino-
  • Exemplary aliphatic amines include, but are not limited to di ethyl enetriamine, tri ethyl enetetramine, tetraethyl enepentamine, 3-
  • Exemplary alkyl amines include, but are not limited to methylamine, ethylamine, propylamine, isopropylamine, butylamine, sec-butylamine, t-butylamine, n-octylamine, 2-ethylhexylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, di-sec-butylamine, di-t-butylamine, di-n-octylamine and di-2-ethylhexylamine.
  • Exemplary acid anhydrides include, but are not limited to, cyclohexane-
  • Exemplary imidazoles include, but are not limited to, imidazole, 1- methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-n- propylimidazole, 2-undecylimidazole, 2- heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl -4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1- benzyl -2-methylimidazole, 1 -benzyl -2-phenylimidazole, 1 -isopropyl -2- methylimidazole, 1 -cyanoethyl-2-methylimidazole, 1 -cyanoethyl -2-ethyl -4- methylimidazole, 1 -cyanoethyl -2-undecylimidazole, 1
  • Exemplary substituted guanidines are methylguanidine, dimethylguanidine, trimethylguanidine, tetramethylguanidine, methylisobiguanidine, dimethylisobiguanidine, tetramethylisobiguanidine, hexamethylisobiguanidine, heptamethylisobiguanidine and cyanoguanidine (dicyandi amide).
  • Representatives of guanamine derivatives which may be mentioned are alkylated benzoguanamine resins, benzoguanamine resins or methoxymethylethoxymethylbenzoguanamine.
  • Substituted ureas may include p-chlorophenyl-N, N-dimethylurea (monuron), 3-phenyl-l, 1- dimethylurea (fenuron) or 3, 4-dichlorophenyl-N,N- dimethylurea (diuron).
  • Exemplary tertiary amines include, but are not limited to, trimethylamine, tripropylamine, triisopropylamine, tributyl amine, tri-sec-butylamine, tri-t-butylamine, tri-n-octylamine, N,N-dimethylaniline, N,N-dimethyl-benzylamine, pyridine, N-methylpiperidine, N-methylmorpholine, N,N-dimethylaminopyridine, derivatives of morpholine such as bis(2-(2,6-dimethyl-4-morpholino)ethyl)-(2-(4- morpholino)ethyl)amine, bis(2-(2,6-dimethyl-4-morpholino)ethyl)-(2-(2,6-diethyl-4- morpholino)ethyl)amine, tris(2-(4-morpholino)ethyl)amine, and tris(2-(4-morpholino)ethy
  • Amine-epoxy adducts are well-known in the art and are described, for example, in U.S. Pat. Nos. 3,756,984, 4,066,625, 4,268,656, 4,360,649, 4,542,202,
  • Such amine-epoxy adducts are the products of the reaction between one or more amine compounds and one or more epoxy compounds.
  • the adduct is a solid which is insoluble in the epoxy resin at room temperature, but which becomes soluble and functions as an accelerator to increase the cure rate upon heating.
  • any type of amine can be used (with heterocyclic amines and/or amines containing at least one secondary nitrogen atom being preferred), imidazole compounds are particularly preferred.
  • Illustrative imidazoles include 2-methyl imidazole, 2,4-dimethyl imidazole, 2-ethyl-4-methyl imidazole, 2-phenyl imidazole and the like.
  • Other suitable amines include, but are not limited to, piperazines, piperidines, pyrazoles, purines, and triazoles.
  • Any kind of epoxy compound can be employed as the other starting material for the adduct, including mono-functional, and multi-functional epoxy compounds such as those described previously with regard to the epoxy resin component.
  • the syntactic structural adhesive of the present disclosure may contain up to about 90 wt.% of hardener, based on the total weight of the syntactic structural adhesive.
  • the syntactic structural adhesive may contain up to about 80 wt.%, or up to about 70 wt.%, or up to about 60 wt.%, or up to about 50 wt.% or up to about 40 wt.% or up to about 30 wt.% or up to about 20 wt.% or even up to about 10 wt.% of the hardener, based on the total weight of the syntactic structural adhesive.
  • the syntactic structural adhesive may optionally contain a flame retardant.
  • the syntactic structural adhesives of the present disclosure may include from about 5 wt.% to about 60 wt.% weight of a flame retardant that consists of a mixture of (i) a compound selected from the group of an alkaline earth metal hydroxide and an aluminum group hydroxide and (ii) at least one phosphorous- containing material.
  • the group of compounds selected from alkaline earth metal hydroxides and aluminum group hydroxides are often referred to as smoke suppressants. Examples of such smoke suppressants include, but are not limited to, aluminum trihydrate, aluminum oxide trihydrate (sometimes also referred to as aluminum hydroxide) and magnesium hydroxide.
  • the phosphorous-containing material may be selected from elemental red phosphorous, melamine phosphate, dimelamine phosphate, melamine pyrophosphate and inorganic phosphinates such as, for example, aluminum phosphinates.
  • multi functional acrylate accelerator in the syntactic structural adhesive.
  • multi-functional acrylate refers to compounds that have at least two acrylate functionalities that are reactive, under the conditions used to cure the syntactic structural adhesive, with at least one of the compounds involved in the curing reaction or formed by the curing reaction.
  • acrylate functionality refers to a functional group having the general structure
  • R may be any group which does not substantially interfere with or prevent reaction of the multi-functional acrylate compound with the epoxy resin.
  • R is independently H or a substituted or unsubstituted alkyl, aryl, oxyalkyl, arylalkyl, or oxyalkylaryl.
  • each R is H.
  • Multi-functional acrylates may include aliphatic urethane acrylates, epoxy acrylates, melamine acrylates, methacrylates and ethylenically unsaturated monomers and resins.
  • Particular examples include, but are not limited to, trimethylol propane triacrylate, 1,6-hexanediol diacrylate, hexafunctional urethane acrylate, hexafunctional epoxy acrylate, tripropylene glycol diacrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, propoxylated neopentyl glycol diacrylate and mixtures thereof.
  • the syntactic structural adhesive may include the optional multi functional acrylate accelerator in an amount of about 0.5 wt.% to about 25 wt.%, based on the total weight of the syntactic structural adhesive.
  • the syntactic structural adhesive may include the optional multi-functional acrylate accelerator in an amount of about 1 wt.% to about 20 wt.%, or from about 2 wt.% to about 17.5 wt.% or even from about 3 wt.% to about 15 wt.%, based on the total weight of the syntactic structural adhesive.
  • the syntactic structural adhesive may also contain one or more other additives which are useful for their intended uses.
  • the optional additives useful in the syntactic structural adhesive may include, but are not limited to, diluents, stabilizers, surfactants, flow modifiers, release agents, matting agents, degassing agents, toughening agents (e.g., carboxyl terminated liquid butadiene acrylonitrile rubber (CTBN), acrylic terminated liquid butadiene acrylonitrile rubber (ATBN), epoxy terminated liquid butadiene acrylonitrile rubber (ETBN), liquid epoxy resin (LER) adducts of elastomers and preformed core-shell rubbers), curing initiators, curing inhibitors, wetting agents, processing aids, fluorescent compounds, UV stabilizers, antioxidants, impact modifiers, corrosion inhibitors, adhesion promoters, high density particulate fillers (e.g., various naturally occurring clays, such as kaolin, bentonite
  • CTBN carboxyl terminated
  • the amount of additives included in the syntactic structural adhesive may be at least about 0.5% by weight, or at least 2% by weight, or at least 5% by weight or at least 10% by weight, based on the total weight of the syntactic structural adhesive. In other aspects, the amount of additives included in the syntactic structural adhesive may be no more than about 30 wt.%, or no more than 25 wt.% by weight, or no more than 20 wt.% or no more than 15 wt.%, based on the total weight of the syntactic structural adhesive.
  • the syntactic structural adhesive may be prepared by stirring and mixing the materials in a state where the materials are heated if needed, without particular limitation.
  • the syntactic structural adhesive of the present disclosure may be a multi-component type (e.g., two-component type) adhesive where at least two of the components of the syntactic structural adhesive are prepared separately and packaged in separate containers (or vessels) and the syntactic structural adhesive is obtained by mixing the two or more separately prepared components together, in some aspects immediately prior to use.
  • the two- components include a Part A which is the epoxy resin and a Part B which is the hardener with the low density particulate filler and the optional materials added to Part A, Part B or Part A and Part B.
  • Part A and Part B are mixed together at a predetermined ratio before use.
  • the amounts of Part A and Part B mixed together will depend upon the desired epoxy to hardener reactive hydrogen molar ratio in the syntactic structural adhesive.
  • Part A and Part B may be mixed at a weight ratio of about 0.1 : 1 to about 3 : 1, or about 0.2: 1 to about 2: 1, or about 0.5: 1 to about 1.5: 1, or even still about 1 : 1.
  • the epoxy resin and hardener are combined so that the ratio of the number of the equivalents of reactive hydrogens in the hardener to the number of the equivalents of epoxides present in the syntactic structural adhesive ranges from about 0.2 to about 2, or from about 0.3 to about 1.5, or even from about 0.4 to about 1, or even still from about 0.5 to about 0.85, and in some cases from about 0.6 to about 0.8, and in further cases from about 0.65 to about 0.75.
  • the syntactic structural adhesive is a two-component adhesive where: Part A includes from about 10 wt.% to about 90 wt.% of an epoxy resin, from about 5 wt.% to about 80 wt.% of a low density particulate filler and from about 5 wt.% to about 60 wt.% of a flame retardant, where the wt.% is based on the total weight of Part A; and, Part B includes from about 10 wt.% to about 90 wt.% of a hardener, from about 5 wt.% to about 80 wt.% of a low density particulate filler and from about 5 wt.% to about 60 wt.% of a flame retardant, where the wt.% is based on the total weight of Part B, and where upon mixing Part A and Part B together to form the syntactic structural adhesive and curing provides a cured material that exhibits at least the following well-balanced
  • Part A can include from about 15 wt.% to about 70 wt.% of an epoxy resin, from about 10 wt.% to about 30 wt.% of a low density particulate filler, from about 3 wt.% to about 20 wt.% of a multifunctional acrylate and from about 5 wt.% to about 40 wt.% of a flame retardant, where the wt.% is based on the total weight of Part A; and, Part B includes from about 15 wt.% to about 80 wt.% of a hardener, from about 10 wt.% to about 30 wt.% of a low density particulate filler and from about 5 wt.% to about 40 wt.% of a flame retardant, where the wt.% is based on the total weight of Part B.
  • kit of parts suitable for preparing the syntactic structural adhesive comprises at least two parts, a Part A comprising the epoxy resin and a Part B comprising the hardener, and where at least one of the Parts A and B of the kit further comprises the low density particulate filler.
  • the low density particulate filler can be included in Part A and in Part B.
  • the Parts of the kit may be packaged and sold in cartridges, such as dual cartridges similar to a caulk gun, or in drums or large containers and then dispersed using meter- mix equipment, or in glass or film capsules.
  • the syntactic structural adhesive may be a“one- component” syntactic structural adhesive in which all of the materials are premixed in a container and stored and where the reactive components do not readily react at ambient or low temperature conditions, such as about -18°C, but instead only react upon activation by an external energy source. After all materials have been combined and mixed, the mixture can be degassed and then sealed in a closed container. There is no criticality to the order of mixture, i.e., the materials may be admixed in any order. In the absence of activation from the external energy source, the syntactic structural adhesive will remain largely unreacted for long periods of time until use.
  • the one-component syntactic structural adhesives of the present disclosure are stable (i.e., remain largely unreacted) for at least 18 months when stored at low temperature conditions, such as about -18°C.
  • External energy sources that may be used to promote the curing reaction include, for example, radiation (i.e., actinic radiation such as ultraviolet light) and/or heat.
  • radiation i.e., actinic radiation such as ultraviolet light
  • heat heat
  • ambient conditions generally refer to temperatures of about 10°C to about 25°C, while low temperature conditions are temperatures that are lower than 0°C and above -40°C.
  • the syntactic structural adhesive is a one-component syntactic structural adhesive comprising from about 10 wt.% to about 70 wt.% of an epoxy resin, from about 2 wt.% to about 50 wt.% of a low density particulate filler and up to about 45 wt.% of a hardener, where the wt.% is based on the total weight of the syntactic structural adhesive, and wherein the one-component syntactic structural adhesive, upon curing, exhibits at least the following well-balanced properties: (i) a density less than 1 g/cm 3 ; (ii) a compression modulus greater than 500 MPa; and (iii) a lap shear strength greater than 750 psi.
  • the one-component syntactic structural adhesive comprises from about 20 wt.% to about 40 wt.% of an epoxy resin, from about 10 wt.% to about 30 wt.% of a low density particulate filler and up to about 30 wt.% of a hardener and optionally up to about 40 wt.% of a flame retardant, where the wt.% is based on the total weight of syntactic structural adhesive.
  • the stirring/mixing method for preparing the syntactic structural adhesive is not particularly limited.
  • a known or customary stirring/mixing unit such as a mixer (e.g., a dissolver, a homogenizer or a static mixer), a kneader, a roll, a bead mill, or a planetary stirring apparatus or even hand mixed.
  • a mixer e.g., a dissolver, a homogenizer or a static mixer
  • a kneader e.g., a kneader, a roll, a bead mill, or a planetary stirring apparatus or even hand mixed.
  • the mixture after stirring and mixing may be subjected to defoam in a vacuum.
  • the syntactic structural adhesive of the present disclosure may be used to supplement or completely eliminate a weld and/or mechanical fastener by applying the syntactic structural adhesive between two or more substrates to be joined and curing the syntactic structural adhesive to form a bonded joint.
  • the syntactic structural adhesive may be applied to any substrate.
  • Substrates include, but are not limited to, a metal, carbon fiber, glass, polymeric material, such as hard plastics, cellulosic- containing material, epoxy fiber composite and mixtures thereof.
  • the metals include, but are not limited to, titanium, ferrous metals, aluminum, aluminum alloys, copper, and other metal and alloy substrates.
  • Non-limiting examples of steels include cold rolled steel, galvanized (zinc coated) steel, electrogalvanized steel, stainless steel, pickled steel, zinc-iron alloy such as GALV ANNEAL® steel, and combinations thereof.
  • cellulosic-containing materials include paper, paperboard, cardboard, plywood and pressed fiber boards, hardwood, softwood, wood veneer, particleboard, chipboard, oriented strand board, and fiberboard. Such materials may be made entirely of wood, such as pine, oak, maple, mahogany, cherry, and the like.
  • the materials may comprise wood in combination with another material, such as a resinous material, i.e., wood/resin composites, such as phenolic composites, composites of wood fibers and thermoplastic polymers, and wood composites reinforced with cement, fibers, or plastic cladding.
  • a resinous material i.e., wood/resin composites, such as phenolic composites, composites of wood fibers and thermoplastic polymers, and wood composites reinforced with cement, fibers, or plastic cladding.
  • At least one of the substrates is a metal.
  • the substrates may be the same or dissimilar.
  • the syntactic structural adhesive may be applied as liquid, paste, and semi-solid or solid that can be liquefied upon heating.
  • the syntactic structural adhesive is in a liquid or paste form.
  • the syntactic structural adhesive may be applied onto the surface of the substrate as a continuous bead, in intermediate dots, stripes, diagonals or any other geometrical form.
  • the syntactic structural adhesive may be applied by any known technique such as by dipping, brushing, spray coating, die coating, roll coating, extruding, injection and contacting the substrate with a bath containing the syntactic structural adhesive manually and/or via automatic machine mixing and dispensing.
  • the substrate may be rinsed with deionized water or an aqueous solution of rinsing agents in order to remove any residue.
  • the substrate can be air dried, for example, by using an air knife, by flashing off the water by brief exposure of the substrate to a high temperature or by passing the substrate between squeegee rolls.
  • the surface of the substrate to which the adhesive of the present disclosure is applied may be a bare, cleaned surface; it may be oily, pretreated with one or more pretreatment compositions, and/or prepainted with one or more coating compositions, primers, etc., applied by any method including, but not limited to, electrodeposition, spraying, dip coating, roll coating, curtain coating, and the like.
  • the syntactic structural adhesive placement options may be augmented by welding or mechanical fastening. Welding can occur as spot welds, as continuous seam welds, or any other weld that can cooperate with the syntactic structural adhesive to form a mechanically sound joint.
  • the syntactic structural adhesive may be used as a structural adhesive in vehicle assembly, such as in the assembly of watercraft vehicles, aircraft vehicles, railway vehicles or motorcraft vehicles, for example, cars and motorbikes, or bicycles.
  • vehicle assembly such as in the assembly of watercraft vehicles, aircraft vehicles, railway vehicles or motorcraft vehicles, for example, cars and motorbikes, or bicycles.
  • the syntactic structural adhesive may be used as a structural adhesive in architecture or household and industrial applications.
  • the syntactic structural adhesive may be used as a welding additive.
  • the present disclosure also provides a method of making a composite article comprising applying the syntactic structural adhesive of the present disclosure to a surface of a substrate and curing the adhesive to form a composite article.
  • a method of forming a bonded joint between at least two or more substrates comprising applying the syntactic structural adhesive of the present disclosure to a surface of at least one of the two or more substrates, joining the two or more substrates so that the syntactic structural adhesive is sandwiched between at least two of the two or more substrates and curing the syntactic structural adhesive to form a bonded joint between the two or more substrates.
  • the syntactic structural adhesives of the present disclosure may have, when cured, at least the following properties: a density of less than 1 g/cm 3 , a compression modulus of at least 500 MPa and a lap shear strength of greater than 750 psi, as measured according to the Examples section below.
  • the density of the syntactic structural adhesive, when cured may be less than 0.95 g/cm 3 , or less than 0.9 g/cm 3 , or less than 0.85g/cm 3 , or less than 0.8 g/cm 3 , or less than 0.75 g/cm 3 , or even less than 0.7 g/cm 3 .
  • the density of the syntactic structural adhesive when cured, may range from at least 0.4 g/cm 3 to less than 1 g/cm 3 , such as from about 0.50 g/cm 3 to about 0.95 g/cm 3 , or from about 0.6 g/cm 3 to about 0.85 g/cm 3 or from about 0.65 g/cm 3 to about 0.75 g/cm 3 .
  • the compression modulus of the syntactic structural adhesive when cured, may be greater than 750 MPa, or greater than 1000 MPa, or greater than 1500 MPa, or greater than 2000 MPa, or even greater than 2250 MPa.
  • the lap shear strength of the syntactic structural adhesive, when cured may be greater than 800 psi, or greater than 1000 psi, or greater than 1250 psi, or greater than 1500 psi, or greater than 1750 psi or even greater than 2000 psi.
  • Lap shear strength was measured using ASTM D1002, which is incorporated herein by reference in its entirety. Two metal plates were bonded together with sample and cured as specified. The assembly was then cut into uniform width lap shear specimens. The test specimens were then placed in the grips of a universal testing machine and pulled at 1.3 mm/min (0.05 in/min) until rupture occurred.
  • ASTM D695 which is incorporated herein by reference in its entirety.
  • the sample was placed between compressive plates parallel to the surface.
  • the sample was then compressed at a uniform rate.
  • the maximum load was recorded along with stress-strain data.
  • An extensometer attached to the front of the fixture was used to determine compression modulus.
  • Density was measured using ASTM D792 and ASTM D 1622, which are incorporated herein by reference in their entirety. The sample was weighed in air then weighed when immersed in distilled water at 23°C using a sinker and wire to hold the sample completely submerged as required. A sample was also weighed then dimensioned with calipers. Density was calculated from these values.
  • the cartridge did not have a nozzle. 75 psig to 85 psig air pressure was used to extrude 2 to 3 inches of sample to clear trapped air. The extruded material was then placed onto a tared sheet of paper for about 10 seconds with the sealant gun operating at full rate. While time could be adjusted depending upon how quickly the tube emptied, it was measured to the nearest second. The extruded compound was then weighed and the extrudability was calculated as follows:
  • the sample was aligned vertically and exposed to a small Bunsen burner flame at its lower edge. The flame was applied for 12 seconds or 60 seconds and then pulled away from the sample. If the sample continued to flame, this flame time was recorded, along with any flaming drips that may have occurred. After the test was over, the burn length was measured.
  • the syntactic structural adhesives of Examples 1 to 4 were prepared by combining in each case the materials listed in Tables 1 and 2 in a half gallon container equipped with a high shear mixer with a 2.5 inch Cowles blade, followed by mixing with a planetary mixer.
  • Table 1 the amounts are given in weight percent, based on the total weight of the syntactic structural adhesive, while in Table 2, the amounts are given in weight percent, based on the total weight of either Part A or Part B.
  • All the ingredients, except the low density particulate filler were mixed with the high shear mixer at a speed up to 2000 rpm for about 2 hours. The mixture was then transferred to a planetary mixture and mixed with the low density particulate filler for about 2 hours, followed by mixing under vacuum for about 10-15 minutes.
  • the syntactic structural adhesive of Example 1 was cured at 177°C for one hour before subjecting the cured specimen to the relevant test.
  • the syntactic structural adhesives of Examples 2, 3 and 4 were cured at room temperature for 3-5 days before subjecting the cured specimens to the relevant tests.
  • BetamateTM 1776LWR adhesive (“Comp. 1”) is a one component epoxy-based composition
  • BetamateTM 73326/73327 (“Comp. 2”)
  • BetamateTM 73312/73312 (“Comp. 3”) adhesives are two-component epoxy-based compositions. Typical processing characteristics, mechanical strength, and physical properties reported by the manufacturer are summarized in Table 3.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Adhesives Or Adhesive Processes (AREA)

Abstract

La présente invention concerne un adhésif structural syntactique comprenant une résine époxy, une charge particulaire de faible densité et un durcisseur qui, lors du durcissement, présente au moins les propriétés bien équilibrées suivantes : (i) une densité inférieure à 1 g/cm3 ; (ii) un module de compression supérieur à 500 MPa ; et (iii) une résistance au cisaillement interlaminaire supérieure à 750 psi. L'adhésif structural syntactique peut être utilisé dans diverses applications, telles que dans des applications automobiles pour coller et/ou sceller des pièces métalliques, plastiques et composites.
EP19909618.1A 2019-02-14 2019-02-14 Adhésifs structuraux syntactiques époxy de faible densité pour des applications automobiles Withdrawn EP3924413A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2019/017938 WO2020167308A1 (fr) 2019-02-14 2019-02-14 Adhésifs structuraux syntactiques époxy de faible densité pour des applications automobiles

Publications (1)

Publication Number Publication Date
EP3924413A1 true EP3924413A1 (fr) 2021-12-22

Family

ID=72045160

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19909618.1A Withdrawn EP3924413A1 (fr) 2019-02-14 2019-02-14 Adhésifs structuraux syntactiques époxy de faible densité pour des applications automobiles

Country Status (7)

Country Link
EP (1) EP3924413A1 (fr)
JP (1) JP2022522072A (fr)
KR (1) KR20210127599A (fr)
CN (1) CN111836851A (fr)
PH (1) PH12020551271A1 (fr)
SG (1) SG11202007159YA (fr)
WO (1) WO2020167308A1 (fr)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7244793B2 (en) * 2003-09-26 2007-07-17 Illinois Tool Works Inc. Adhesive compositions
JP6824179B2 (ja) * 2015-03-26 2021-02-03 ハンツマン・アドヴァンスト・マテリアルズ・ライセンシング・（スイッツランド）・ゲーエムベーハー 屋外用製品を製造するための熱硬化性エポキシ樹脂組成物、およびそれから得られる屋外用製品
EP3275915B1 (fr) * 2016-07-29 2022-11-30 3M Innovative Properties Company Durcissement rapide non-halogène adhésif époxy à deux composants présentant des propriétés ignifugeantes

Also Published As

Publication number Publication date
CN111836851A (zh) 2020-10-27
SG11202007159YA (en) 2020-09-29
JP2022522072A (ja) 2022-04-14
PH12020551271A1 (en) 2021-07-05
WO2020167308A1 (fr) 2020-08-20
KR20210127599A (ko) 2021-10-22

Similar Documents

Publication Publication Date Title
CA2753569C (fr) Compositions adhesives de type epoxy dotees d'une resistance mecanique elevee sur une large plage de temperatures
EP3275913B1 (fr) Compositions adhésives époxy haute performance
US20040181013A1 (en) Impact resistant epoxide resin compositions
CN105121498B (zh) 环氧粘合剂用多加速剂体系
US20050022929A1 (en) Multi-phase structural adhesives
JP2010516844A (ja) 高強度エポキシ接着剤及びその使用
JPH11503775A (ja) ジチオオキサミド接着促進剤含有エポキシ接着剤
ZA200102837B (en) Impact-resistant epoxide resin compositions.
JP2004515565A (ja) 耐衝撃性エポキシ樹脂組成物
US20230250274A1 (en) Coating compositions
EP3924413A1 (fr) Adhésifs structuraux syntactiques époxy de faible densité pour des applications automobiles
AU2019422011A1 (en) Low density epoxy syntactic structural adhesives for automotive applications
US20220275148A1 (en) Coating compositions
WO2024206319A1 (fr) Adhésifs époxy durables en cas de collision avec une fenêtre de durcissement étendue
AU2020336147B2 (en) Coating compositions
MXPA01003482A (en) Impact-resistant epoxide resin compositions

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20200721

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20220315