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
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/4009—Two or more macromolecular compounds not provided for in one single group of groups C08G18/42 - C08G18/64
  • C08G18/4045—Mixtures of compounds of group C08G18/58 with other macromolecular compounds
• • 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
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/83—Chemically modified polymers
  • C08G18/831—Chemically modified polymers by oxygen-containing compounds inclusive of carbonic acid halogenides, carboxylic acid halogenides and epoxy halides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
  • C08L75/04—Polyurethanes
• • 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
  • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
  • C09J175/04—Polyurethanes
• • 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
  • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
  • C09J175/04—Polyurethanes
  • C09J175/06—Polyurethanes from polyesters
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/38—Improvement of the adhesion between the insulating substrate and the metal
  • H05K3/386—Improvement of the adhesion between the insulating substrate and the metal by the use of an organic polymeric bonding layer, e.g. adhesive

Definitions

• This invention is directed to three-dimensional polymeric adhesive materials and methods for producing such materials.
• Adhesive materials and systems that are currently available meet some of the requirements for such properties as peel strength, chemical resistance, moisture resistance, high temperature stability, dimensional stability, especially in the Z-axis direction, and ease of processing. However, these materials and systems typically fail to meet one or more of these requirements. Therefore, a need exists for an adhesive material that meets all of the requirements for use under severe environmental conditions while retaining ease of application.
• One aspect of the present invention is a process for producing a three-dimensional polymeric adhesive material.
• the process comprises:
• the starting polymer can contain an active hydrogen and have a maximum acid value of 2.
• a starting polymer can be selected from the group consisting of polycarboxylic acids, polyesters, polyamides, polyacrylics, polyfunctional phenolic resins, and mixtures thereof.
• the starting polymer is a high molecular weight polyester.
• the starting polymer can be a polyfunctional hydroxy-containing polymer having a hydroxy number of at least 10.
• the polyfunctional hydroxy-containing polymer is selected from the group consisting of polyols, polyesters, polyurethanes, and mixtures thereof.
• the polyfunctional nucleophile is a polyfunctional nitrogen-containing compound. More preferably, the polyfunctional nitrogen-containing compound is selected from the group consisting of polyamines, polyaziridines, polyisocyanates, and mixtures thereof. Most preferably, the polyfunctional nitrogen- containing compound is a polyisocyanate.
• the polyelectrophile comprises at least one polyepoxide. More preferably, the polyepoxide is selected from the group consisting of bisphenol A- epichlorohydrin epoxies, novolac epoxies, and mixtures thereof. Most preferably, the polyexpoxide comprises a mixture of bisphenol A-epichlorohydrin epoxies and novolac epoxies.
• the step of reacting the adduct product with the at least one polyepoxide comprises heating a mixture of the adduct product and the at least one polyepoxide to a temperature between about 250°F and about 400°F.
• the high molecular weight polyester comprises from about 50% to about 90% by weight of the three-dimensional polymeric adhesive material and the polyepoxide comprises from about 10% to.about 50% by weight of the three-dimensional polymeric adhesive material.
• Another aspect of the present invention is a process for bonding at least two substrates.
• the process comprises the steps of:
• the substrates are selected from the group consisting of film substrates, foil substrates, and hardboard substrates.
• the adhesive comprises: (1) at least two linear polymer moieties, each moiety comprising a polymer containing nucleophilic nitrogen atoms capable of reaction with an electrophile; and
• the linear polymer moieties are selected from the group consisting of polycarboxylic acids, polyesters, polyamides, polyacrylics, polyfunctional phenolic resins, and mixtures thereof.
• the linear polymer moieties are formed by reaction of a hydroxy-containing polymer with a polyfunctional nitrogen-containing nucleophile.
• the polyfunctional nitrogen- containing nucleophile is selected from the group consisting of polyamines, polyaziridines, polyisocyanates, and mixtures thereof.
• One preferred version of the three-dimensional polymeric adhesive of the present invention comprises:
• cross-links between the nitrogens of the urethane linked polymer moieties each cross-link comprising a phenyl-containing polymer linked to the nitrogen atoms of the urethane linkages by -CH 2 -CH0H- linkages, with the methylene groups of the linkages being bonded directly to the nitrogen atoms such that the cross-links form a three-dimensional polymeric structure.
• the cross— links preferably comprise at least one polyepoxide selected from the group consisting of bisphenol A-epichlorohydrin epoxies, novolac epoxies, and mixtures thereof.
• the polyepoxide comprises a mixture of bisphenol A-epichlorohydrin epoxies having the formula
• n is an integer from 1 to about 20, n being independently chosen for the bisphenol A-epichlorohydrin epoxies and for the novolac epoxies.
• the adhesive material of the present invention can be used to bond at least two substrates, thereby forming a composite structure.
• a composite structure formed according to the invention comprises: (1 ) at least two bondable substrates; and
• the adhesive material comprising:
• cross-links between the nitrogens of the polymer moieties each cross-link comprising a polymer linked to the nitrogen atoms of the polymer moieties through reaction of an electrophile with the nitrogen atoms.
• One aspect of the present invention is a process for producing a three-dimensional polymeric adhesive material.
• the polymeric adhesive material produced by this process has improved peel strength, chemical resistance, moisture resistance, high temperature stability, and dimensional stability. It is- easy to process and is particularly suitable for use with electronic construction materials, such as printed circuit boards.
• this process comprises:
• the starting polymer can contain an active hydrogen, with a maximum acid value of 2.
• Such polymers can be polycarboxylic acids, polyesters, polyamides, polyacrylics, polyfunctional phenolic resins, or mixtures thereof.
• the starting polymer can be a polyfunctional hydroxy-containing polymer having a hydroxy number of at least 10.
• the polyfunctional hydroxy-containing polymer can be a polyol, a polyester, a polyurethane, or a mixture thereof.
• the starting polymer is a high molecular weight polyester with hydroxyl end-group functionality of the alcohol type.
• the polyfunctional nucleophile can be a polyfunctional nitrogen-containing compound.
• Such compounds include polyamines, polyaziridines, polyisocyanates, and mixtures thereof.
• the polyfunctional nitrogen-containing compound is a polyisocyanate.
• a particularly suitable starting polymer is a polyester resin such as DuPont 49002 base.
• a particularly suitable polyelectrophile is a polyfunctional isocyanate sold by Mobay.Chemical Corp., Pittsburgh, Pennsylvania, under the name of Mondur MRS, which is a polymethylene polyphenylene ester of isocyanic acid.
• Carbon atoms of alkyl and/or aryl moieties within the starting polymer or polyfunctional nucleophile can be optionally substituted with methyl and/or C 2 -C 5 alkyl.
• the terms "starting polymer” and “polyfunctional nucleophile”, as used herein, include compounds optionally substituted with methyl and/or C 2 -C 3 alkyl.
• reaction of the starting polymer with the polyfunctional nucleophile takes place slowly at room temperature and takes place more rapidly at about 250°F. Typically, this reaction is performed in a solvent, such as a 90%:10% mixture of methylene chloride:cyclohexanone.
• the second stage of the process comprised is reacting the adduct product with a polyelectrophile to generate the three-dimensional polymeric adhesive material.
• the polyelectrophile is preferably a polyepoxide. More preferably, it is a polyepoxide selected from the group consisting of bisphenol A- epichlorohydrin epoxies, novolac epoxies, or a mixture thereof. Most preferably, the polyelectrophile is a mixture of ⁇ bisphenol A— epichlorohydrin epoxy, such as Celanese Epi-Rez-51 32, and a novolac epoxy, such as Dow DEN 438.
• the bisphenol A-epichlorohydrin epoxy has the following structure:
• n is an integer from 1 to about 20.
• the novolac epoxy has the following structure:
• n is an integer from 1 to about 20.
• the values of n are independently chosen for the bis-epi and novolac epoxies.
• the high molecular weight polyester comprises from about 50% to about 90% by weight of the three-dimensional polymeric adhesive material and the polyepoxide comprises from about 10% to about 50% by weight of the three-dimensional polymeric adhesive material.
• the pressure at which the reaction occurs is generally not critical .
• the reaction typically takes place at atmospheric pressure.
• the reaction typically occurs in an aprotic, moderately polar solvent or a mixture of such solvents .
• exemplary solvents are a mixture of methylene chloride and cyclohexanone or methyl ethyl ketone, or a mixture of methylene chloride and cyclohexanone together with methyl ethyl ketone.
• suitable solvents are not to be limited to these combinations,- the choice of solvent is generally not critical .
• the process of producing the adhesive of the present invention can be incorporated into a process for bonding at least two substrates.
• this bonding process comprises of the steps of:
• the substrates used for this procedure can be film substrates, foil substrates, or hardboard substrates.
• a typical example of a film substrate is polyimide film.
• the substrates can be of the same materials or different materials.
• the substrates can be electronic circuit boards or other electronic structural components.
• Another aspect of the invention is an improved three-dimensional polymeric adhesive material comprising:
• the adhesive comprises:
• cross-links between the nitrogen of the urethane linked polymer moieties comprising a phenyl-containing polymer linked to the nitrogen atoms of the polyurethanes by -CH 2 -CH0H- linkages with the CH 2 moieties being located adjacent to the nitrogen atoms.
• this adhesive material can be formed in situ for bonding at least two substrates.
• the substrates can be film substrates, foil substrates, or hardboard substrates.
• the composite material comprises:
• An example of the adhesive material of the present invention includes the following components: (1) a polyester resin having a solids content of 17-20% comprised of Dupont 49002 base in a solvent mixture of 90%: 10% (w/w) methylene chloride: cyclohexanone;
• the adhesive coating composition is made by adding 80% by solids of the polyester component, 10% by solids of the epoxy novolac, 10% by solids of the bis- epi epoxy, and 1.2 parts by weight of the isocyanate in an open container without agitation. The composition is then agitated well for 1 to 5 minutes. The container is then capped with an airtight lid for 30 minutes to allow for the onset of the isocyanate/polyester reaction.
• polyester and isocyanate are combined, thoroughly mixed, and then allowed to stand at room temperature for a minimum of 30 minutes prior to the epoxy addition to allow onset of the isocyanate/polyester reaction.
• the adhesive coating composition is then applied by means of the reverse roll coating technique to a 1 mil polyimide film to yield a 1 mil dry coat weight. Drying (i.e., removal of the solvents) is accomplished through a 75-foot, 3-zone oven at 212°F and 25 feet per minute.
• the coated substrate is then positioned next to the treated side of a 1 ounce copper foil, where the copper foil surface is treated with Oak CMC-111 compound to enhance bondability.
• the polyimide film and copper foil are heated to a temperature of 225°F to 400°F with an applied pressure of 80 psi (pounds/square inch) to 120 psi through a coater/laminator combining station as part of a continuous operation.
• the resulting roll is brought onto a six inch core, left at room temperature for 1 to 7 days, then post cured as follows: 2 hours at 150°F, 2 hours at 275°F, and 2 hours at 350°F.
• a composite structure was prepared according to the first of the above procedures.
• the resulting composite structure exhibited the properties shown in Table 1 when tested per ANSI/IPC-FC-232B and 241B procedures:
• the present invention provides an adhesive system with extremely balanced properties and the added benefit of superior Z-axis stability through a unique curing mechanism. More specifically, the present invention provides an epoxy-based laminating adhesive that can be continuously processed and cured without the evolution of byproducts to provide a flexible bond-ply with superior overall properties, including excellent Z- axis stability.
• the adhesive material is applicable to film substrates such as polyimide, foil substrates such as copper, and hardboard substrates, such as FR4
• the adhesive of the present invention also possesses superior peel strength, chemical resistance, moisture resistance, and temperature stability. It is particularly suitable for use in the bonding of electronic construction materials, such as those intended for use in severe environmental conditions. In particular, the adhesive of the present invention is suitable for use in under-the-hood automotive and military applications.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• General Chemical & Material Sciences (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Laminated Bodies (AREA)

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Citations (5)

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• 1993
  • 1993-04-06 CA CA002133839A patent/CA2133839A1/en not_active Abandoned
  • 1993-04-06 EP EP93909150A patent/EP0635035A4/de not_active Withdrawn
  • 1993-04-06 WO PCT/US1993/002677 patent/WO1993020123A1/en not_active Ceased
  • 1993-04-06 JP JP5517523A patent/JPH07509010A/ja active Pending

Patent Citations (5)

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