WO2005047393A1 - Adhésif thermofusible réactif - Google Patents

Adhésif thermofusible réactif Download PDF

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Publication number
WO2005047393A1
WO2005047393A1 PCT/EP2004/012476 EP2004012476W WO2005047393A1 WO 2005047393 A1 WO2005047393 A1 WO 2005047393A1 EP 2004012476 W EP2004012476 W EP 2004012476W WO 2005047393 A1 WO2005047393 A1 WO 2005047393A1
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WIPO (PCT)
Prior art keywords
composition
epoxy resin
softening point
temperature
ethylene
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PCT/EP2004/012476
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English (en)
Inventor
Franciscus J. T. Krabbenborg
Philippe Belot
Jacobus Jan Houg
Martine Rousse
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Dow Global Technologies Inc.
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Publication of WO2005047393A1 publication Critical patent/WO2005047393A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F299/00—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers
    • C08F299/02—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers from unsaturated polycondensates
    • C08F299/022—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers from unsaturated polycondensates from polycondensates with side or terminal unsaturations
    • C08F299/024—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers from unsaturated polycondensates from polycondensates with side or terminal unsaturations the unsaturation being in acrylic or methacrylic groups
    • 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
    • C09J123/00—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers
    • C09J123/02—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers not modified by chemical after-treatment
    • C09J123/04—Homopolymers or copolymers of ethene
    • C09J123/08—Copolymers of ethene
    • C09J123/0846—Copolymers of ethene with unsaturated hydrocarbons containing other atoms than carbon or hydrogen atoms
    • C09J123/0869—Acids or derivatives thereof
    • 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
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
    • C08L2205/035—Polymer mixtures characterised by other features containing three or more polymers in a blend containing four or more polymers in a blend
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
    • C08L2666/02—Organic macromolecular compounds, natural resins, waxes or and bituminous materials
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
    • C08L2666/02—Organic macromolecular compounds, natural resins, waxes or and bituminous materials
    • C08L2666/14—Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
    • C08L2666/22—Macromolecular compounds not provided for in C08L2666/16 - C08L2666/20
    • 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
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers

Definitions

  • This invention relates to adhesive compositions, and in particular to compositions of the type able to form an initial bond between the parts to be bonded such that the parts can be handled after the initial bonding process, and which subsequently form a permanent bond by a reactive curing process.
  • adhesives are generally known as reactive hot melt adhesives (RHMAs).
  • RHMAs may find application, for example as "sealer" adhesives for use in an automotive body shop or paint-shop (for example to protect weld-points or flange/gaps from corrosive attacks and humidity, water, dust particles intrusion), or to bond two metal or plastics substrates and/or to increase damping or stiffening.
  • compositions with paste-like or liquid consistency with a range of viscosity depending on the application.
  • existing reactive compositions are based on rubber, PVC, epoxy resins, acrylics or mixtures thereof.
  • these liquid adhesives have a number of problems or difficulties associated with them.
  • liquid adhesives may be difficult or messy to handle or apply, may be flammable, may present environmental concerns involving volatile organic compounds (“VOCs”) and solvent recovery, or may present toxicological concerns.
  • VOCs volatile organic compounds
  • liquid and low viscous adhesives When used to adhere steel and or aluminium, liquid and low viscous adhesives have a tendency to "bleed through” other areas which can . destroy the visible decorative surface.
  • the "bleed through” problem associated with liquid adhesives can be solved to some extent using thickeners. Often, due to its high viscosity, the paste needs to be heated to allow efficient application, narrowing the utilization window of the formulated paste.
  • WO02/50184 discloses a vibration damping composition which is typically in the form of a paste comprising an epoxy resin, a crosslinking agent and a thermoplastic alpha-olefin/vinyl aromatic interpolymer.
  • a vibration damping composition which is typically in the form of a paste comprising an epoxy resin, a crosslinking agent and a thermoplastic alpha-olefin/vinyl aromatic interpolymer.
  • compositions need to have enough viscosity/strength after application in order to withstand the panel degreasing and pre-treatment process (so called wash-off resistance to dipping and jet-spray of water/alkaline/dispersion solutions).
  • a post-application pre-curing step prior to the final cure, to eliminate the above mentioned issues would affect the cycle time, space requirement, and quality of the parts produced.
  • WO-A-0172922 discloses a so-called "dryblend” adhesive, comprising thermoplastic polymer particles. Such adhesives require to be shipped in the absence of air and moisture, and require high shear melting before application. As soon as such blending has taken place, the curing action begins, and therefore the adhesives must be homogenised immediately before use. They are applied immediately after they are homogenised, because after homogenisation, the reaction is initiated and the batches only have a limited pot life. The homogenised composition does not have the lapshear strength required for use as so-called “semi-structural" adhesives.
  • a "semi- structural" adhesive is generally considered to be one with a Lap Shear strength of at least 4 MPa.
  • DE3938376 discloses a one component heat-curing powder adhesive comprising a mixture of solid and liquid epoxy resins and a polyvinyl acetate plastomer. This adhesive is useful for bonding friction linings with steel, especially in brake and clutch linings for vehicles. A two-step process is used to produce the adhesive, and the resulting composition is not storage stable under pressure, such as when it is stored in large quantities.
  • US4,517,340 discloses an adhesive composition
  • a thermoplastic polyamide a thermoplastic copolymer of an alkene with an unsaturated ester of an alfanol and a carboxylic acid
  • a thermoplastic epoxy resin a thermoplastic epoxy resin
  • a reactive hot melt composition which is a solid at ambient temperature (20°C), and which has excellent initial adhesion as well as excellent properties of the final cured composition.
  • the composition can be formulated into free-flowing pellets or beads, which can be heated to form an extrudable mass, and thereafter applied using conventional extrusion techniques. It can also, if desired, be formulated into sheets or films for use between two parts to be adhered.
  • the composition therefore overcomes many of the difficulties encountered by prior art reactive hotmelt adhesives for "semi-structural" applications used in car body construction.
  • a reactive hot melt composition having a softening point of at least 45°C, preferably at least 50°C comprising: an epoxy resin having a softening point of at least 45°C, preferably at least 50°C, and at least one random inte ⁇ olymer of ethylene with at least one additional comonomer, which is an olefinically unsaturated carboxylic acid or anhydride, an olefinically unsaturated carboxylic acid ester, or a vinyl ester.
  • the epoxy resin is such that the composition may be caused to adhere to a surface by heating the composition to an application temperature in excess of the softening point of the composition, to IO ⁇ . a eit ⁇ auuesive composition.
  • Tue composition is thereafter curable by heating to a curing temperature to cure the epoxy resin, the curing temperature being in excess of the application temperature.
  • the composition maybe melted, extruded and applied to a surface at a temperature of from 110 to 140°C without curing, and the composition is thereafter curable by heating to a curing temperature of greater than 140°C, preferably greater than 180°C for a time of more than 5 minutes.
  • softening point as used herein is intended to refer to "Mettler Softening Point”, as determined by ASTM D3104-99
  • the composition consists of the epoxy resin, the at least one random inte ⁇ olymer of ethylene, optionally a polyester, and optionally a curing agent. More preferably, the composition consists essentially of the epoxy resin, the at least one random inte ⁇ olymer of ethylene, optionally the polyester and optionally the curing agent. In a particularly preferred embodiment, the composition consists essentially of the epoxy resin, the at least one random inte ⁇ olymer of ethylene, the curing agent and optionally the polyester.
  • the ethylene inte ⁇ olymer serves to increase and control the viscosity of the composition at low shear rates, and so increase polymer bead stability both during pellet formation and on application to a surface for bonding at 100 to 150°C.
  • the comonomer is preferably selected from acrylic acid, methacrylic acid, methylacrylate, methylmethacrylate, ethylacrylate, ethylmethacrylate, butylacrylate, butylmethacrylate, vinyl acetate, maleic anhydride, and/or glycidyl methacrylate.
  • the ethylene inte ⁇ olymer may be, for example, an ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, an ethylene-acrylic acid-methacrylic acid te ⁇ olymer, an ethylene- vinyl acetate copolymer, an ethylene-methyl acrylate copolymer an ethylene-ethyl acrylate copolymer, an ethylene-maleic anhydride copolymer, an ethylene-glycidyl methacrylate copolymer, an ethylene-vinyl acetate- maleic anhydride te ⁇ olymer or ethylene-ethyl acrylate-glycidyl methacrylate te ⁇ olymer.
  • the preferred ethylene inte ⁇ olymers are made by free-radical polymerisation and contain 20-30% of a comonomer selected from alkyl acrylates, alkyl methacrylates, vinyl esters, olefinically unsaturated carboxylic acids, glycidyl methacrylate and maleic anhydride.
  • the ethylene inte ⁇ olymer maybe used in a total an amount of from 10 to 60 %, preferably from 10 to 30 %, more preferably from 10 to 20 % by weight, based on the total composition.
  • the ethylene inte ⁇ olymer is an ethylene-acrylic acid (EAA) copolymer
  • the copolymer preferably contains from 10 to 30%, preferably 20 to 30% by weight acrylic acid.
  • the EAA has a melt flow rate (MFR), when measured according to ISOl 133 at 190°C and 2.16 kg, of more than 100 g/10 (more preferably from 300 to 1300g/10 min).
  • MFR melt flow rate
  • suitable commercially available ethylene- acrylic acid or ethylene-methacrylic acid copolymers are PrimacorTM 5980 and 5990 from The Dow Chemical Company, NucrelTM from Dupont and EscorTM from Exxon Mobil Chemical. Particularly preferred is PrimacorTM 5990.
  • the ethylene inte ⁇ olymer is an ethylene-methacrylic acid (EMAA) copolymer
  • the copolymer preferably contains from 10 to 30%, preferably 20 to 30% by weight methacrylic acid.
  • the EMAA preferably has a MFR, when measured according to ISOl 133 at 190°C and 2.16 kg, of from 300 to 1300g/10min.
  • An example of a suitable commercially available ethylene-methacrylic acid copolymer is NucrelTM 2940 from Dupont.
  • the ethylene inte ⁇ olymer is an ethylene-vinyl acetate copolymer
  • the copolymer preferably has a vinyl acetate content of greater than 20%, preferably from 30 to 40% by weight.
  • the EVA copolymer preferably has a MFR when measured according to ISO 1133 at 190°C and 2.16kg of greater than 50 g 10min., more preferably from 200 to 600 g/min.
  • Suitable commercially available EVA copolymers include EvataneTM from Atofina and Escor ⁇ neTM from Exxon Mobil. Particularly preferred are EscoreneTM UL05540 (MFR of 60g/10 min.) and EvataneTM 33400 (MFR of 350 to 450 g/10 min. and a vinyl acetate content of 30%).
  • the inte ⁇ olymer When the ethylene inte ⁇ olymer is a copolymer having a monomer selected from the acrylate, or methacrylate, the inte ⁇ olymer has an acrylate content of greater than 18%, preferably 20-30%.
  • Suitable inte ⁇ olymers are, for example, ethylene- methylacrylic ester copolymers, ethylene-ethylacrylic ester copolymers, or ethylene- butylacrylic ester copolymers.
  • Commercially available examples of suitable inte ⁇ olymers include LotrylTM from Atofina, EnableTM and OptemaTM from Exxon Mobil Chemical and Amplify EA series from The Dow Chemical Company (Amplify EA 100, 101, 102 and 104).
  • Suitable te ⁇ olymers are ethylene- vinyl-acetate-maleic anhydride polymers (for example Orevac TTM ), ethylene-acrylate-maleic anhydride polymers (for example LotaderTM AX4720), ethylene-acrylate-glycidyl methacrylate polymers (for example LotaderTM AX8900 and AX8950) and te ⁇ olymers containing acrylate and/or methacrylate units and/or methyl acrylate units (for example EscorTM te ⁇ olymer from Exxon Mobil Chemical).
  • Orevac TTM ethylene-acrylate-maleic anhydride polymers
  • ethylene-acrylate-maleic anhydride polymers for example LotaderTM AX4720
  • ethylene-acrylate-glycidyl methacrylate polymers for example LotaderTM AX8900 and AX8950
  • Methacrylate and/or acrylate-containing polymers for example ethylene-acrylic ester- glycidyl methacrylate polymers, preferably contain at least 25% by weight of ethylenically unsaturated monomer units and have an MFR when measured according to ISO 1133 of less than 10 g/lOmin. at 190°C and 2.16kg.
  • Preferred commercial polymers include LotaderTM AX 8900 which has a MFR of 6 g/10 min. and 32% by weight of ethylenically unsaturated monomer units and AX4720 which has a MFR of 7 g/10 min. and 30 % by weight of ethylenically unsaturated monomer units.
  • Iono er resins of carboxylic copolymers for example Surlyn resins from Dupont
  • sodium, zinc, lithium or other inorganic salts have been found to be useful optional ethylene copolymers for use in the composition.
  • the composition may also include minor amounts of additional polymers and copolymers, for example non-random copolymers, e.g., grafted copolymers.
  • additional polymers and copolymers for example non-random copolymers, e.g., grafted copolymers.
  • grafted copolymers which may be used are maleic anhydride grafted elastomers with a high content of maleic anhydride, for example having a maleic anhydride content of from 0.5 to 2 weight %.
  • maleic anhydride grafted elastomers include LotaderTM 8200, LotrylTM 35BA, LotrylTM28BA 175 and OrevacTMte ⁇ olymer EVA 9305 from ATO, ExxelorTM VA1801 (Semi crystalline) and ExxelorTM 1803(Amo ⁇ hous) from Exxon, FusabondTM N series: MF416D, MN493D, MN494D and MO525D and Fusabond TM C series MCI 90D and MC250D from Dupont.
  • polymers which may be useful in addition to the ethylene inte ⁇ olymers include other olef ⁇ nic and or styrenic base adhesive polymers which have carboxylic acid functionality and/or anhydride functionality.
  • examples include polybutylene- maleic anhydride, polybutylene-graft-maleic anhydride, polypropylene-graft-maleic anhydride, and styrenic-butadiene block copolymer-graft-maleic anhydride.
  • Such additional polymers and copolymers are preferably present in an amount of from 5 to 10 percent, based on the total composition.
  • the composition preferably comprises less than 10 percent by weight of a thermoplastic polyamide and more preferably is substantially free of thermoplastic polyamide.
  • the ethylene inte ⁇ olymer(s) should preferably have a melting point less than 105°C and preferably less than 95 °C. Additionally the inte ⁇ lymer(s) should preferably have a melt index of at least 2 g 10 minutes, more preferably at least 5 g/10 minutes and most preferably at least 20 g/10 minutes when tested according to ASTM D-1238 (190°C, 2.16kg). If the melt index of the ethylene inte ⁇ olymers is too low, it will result in insufficient flow and poor wet-out of the composition at application.
  • the ethylene inte ⁇ olymer having a relatively high melt index. This is because of the reaction between carboxylic acid and epoxy resin which occurs during compounding and results in an increase of viscosity.
  • the ethylene inte ⁇ olymers are chosen to allow high levels of epoxy resin (up to 90% by weight), along with the optional curing agent and polyester to be used, and the yet still be able to produce the composition in a one step mixing process
  • the composition includes an epoxy resin which has a softening point of at least 50°C, and thus is solid at ambient temperature (20°C).
  • the solid epoxy resin preferably constitutes from 40 to 90%, more preferably from 60 to 80 % and most preferably from 70 to 80 % based on the total weight of the composition.
  • the use of a material with a softening point of at least 50°C enables the composition to be produced in the form of hard granules which are non blocking, i.e., free flowing at room temperature.
  • the solid epoxy resin may be any resin known by those skilled in the art having one or more epoxy groups, and may include aromatic and aliphatic types, and mixtures thereof.
  • Preferred aromatic epoxy resins are epoxy resins having bisphenol moieties in the backbone of the epoxy resin.
  • Representative of preferred bisphenol resins useful in this invention are those disclosed in U.S. Patent No. 5,308,895 at column 8, line 6 and represented by Formula 6.
  • the most preferred aromatic epoxy resins are bisphenol-A based epoxy resins and bisphenol-F based epoxy resins.
  • Bisphenol-A based epoxy resin are preferred.
  • Particularly preferred epoxy resins include resins based on diglycidyl ethers of Bisphenol A, for example the products supplied by The Dow Chemical Company under the Trade Marks D.E.R. or DERAKANE (in particular D.E.R. 662) and Novalac modified epoxy resins, for example, products supplied by The Dow Chemical Company under the Trade Mark D.E.N.
  • a further epoxy resin with a lower softening point may also be employed, provided that the overall softening point of the composition is not less than 50°C.
  • additional epoxy resins are the reaction product of DGEBA, bis-A and a fatty acid and or a dimer fatty acid derived from a natural oil such as for example linseed, tall, or castor oil fatty acids. Those resins are typically highly viscous liquids to solids at room temperature. Processes for making such resins are described in column 8, line 6 of U.S. Patent No. 5,308,895. Such fatty acid modification of a bisphenol-A epoxy resin, as well as other known modifications, permit the adjustment of the mechanical performance of the final cured product
  • epoxy resins which may be used either alone or in combination with bisphenol-A based epoxies , those are for example, so called novolac epoxy resins, reaction products of epichlorohydrin with a novolac resins (e.g. type D.E.R.* 642U, available from The Dow Chemical Company ), and vinylester resins, (i.e., the reaction of product of acrylic acid/methacrylic acid with an epoxy resin).
  • novolac epoxy resins reaction products of epichlorohydrin with a novolac resins (e.g. type D.E.R.* 642U, available from The Dow Chemical Company ), and vinylester resins, (i.e., the reaction of product of acrylic acid/methacrylic acid with an epoxy resin).
  • Example are Derakane* grades from The Dow Chemical Company.
  • suitable epoxy resins are bisphenol-A type solid epoxy resins might be modified by aliphatic epoxy resins derived from containing polyether chains. Such epoxy resins are preferably prepared from one or more alkylene oxides. Representative examples of such aliphatic epoxy resins are those described in U.S. Patent No. 5,308,895 at column 8, line 9 and formula 9 and the description thereof following. Preferably, the aliphatic epoxy resin contains in its backbone ethylene oxide, propylene oxide or a mixture thereof.
  • the epoxy resin may also include a mixture of a bisphenol-A type epoxy resin and an aliphatic epoxy resin.
  • Example of such mixtures are the materials described in WO 99/16840.
  • the more flexible aliphatic epoxy resin is used in combination with the more rigid bisphenol-A based epoxy resin in a ratio which provide the desired the glass transition temperature of the final cured product.
  • the aliphatic epoxy resin can be included as a reactive partner during the manufacturing process of the bisphenol-A based epoxy resin together with the DGEBA and bisphenol-A reactants. In this case aromatic-aliphatic hybrid epoxy resin structures are obtained.
  • the number average molecular weight (M n ) of the bisphenol-A based epoxy resin is preferably greater than 700, more preferably greater than 800, and more preferably still, greater than 900. Such resins show decreased tendency to skin-sensitizing. Generally M n is in the range of from 700 to 5000, preferably from 800 to 5000, more preferably from 900 to 3000, and more preferably still from 900 to 2000.
  • the molecular weight of the additional (normally aliphatic) liquid epoxy resin is generally from 300 to 4000, preferably from 500 to 2000, and more preferably from 500 to 1000.
  • the epoxy resin is preferably one which is non-irritating and non-sensitizing by skin contact.
  • a curing agent (also referred to as a cure initiator) may be used to cure the epoxy resin between 180 to 190°C thereby developing final adhesive strength.
  • Curing agents useful in the present invention include amines, amides, amidoamine, onium halides, boron trifluorides or hydrazides.
  • Preferred curing agents are dicyandiamine (for example Dyhard 100S supplied by SKW Trostberg) and crosslinking catalysts (for example 2-methylimidazole) and TDI-uron latent accelerators (e.g., Dyhard UR 500 supplied by SKW Trostberg).
  • the curing agent is preferably used in an amount of from 3 to 5 weight % of the total composition.
  • Curing accelerators or catalysts can be used in addition to or instead of the curing agent to lower the curing temperature of the reactive hotmelt composition.
  • Preferred curing accelerators are imidazoles and modified imidazoles, such as 2-methylimidazole, onium halides, such as tetrabutyl ammonium bromide, tetrabutyl phosphonium bromide or ethyltriphenylphosphonium acetate and epoxy amine adducts such as Ajicure My-24 available from Ajinomoto.
  • a particular preferred accelerator is 2-methylimidazole (for example Dyhard UR500).
  • the curing initiator can act as a latent catalyst in the reactive hotmelt composition, and is effective to accelerate the curing reaction of the epoxy resin and lower the curing reaction, for example to 140-150°C.
  • the curing accelerator is preferably employed in an amount of from 0.5 to 1 weight % of the total reactive hotmelt composition.
  • a melt rheometer such as a Brabender Plasticorder Rheometer or a Haake Rheometer can be used to monitor rheological changes with respect to time and or temperature.
  • a Rheometrics RDS-2 parallel plate rheometer can be utilized with a dynamic temperature ramp to evaluate melt viscosity versus increasing temperature.
  • a non-curing composition will typically decrease in viscosity as temperature is increased, while a curable composition will initially exhibit a viscosity reduction with increasing temperature until the cure reaction is initiated, whereupon the viscosity will increase as the temperature (or time) is increased.
  • the composition may preferably also comprise from 0 to 40 % based on the total weight of the composition, of a polyester.
  • a polyester resins can serve to improve the adhesion of the composition, in particular to steel substrates, both before and after curing.
  • the polyester is preferably poly-e-caprolactone (for example those available from The Dow Chemical Company under the tradename ToneTM, in particular those sold under the designations Tone P-737, P-752, P-767 and P-787) Tone P-767 is particularly preferred.
  • An alternative preferred polyester is polyepoxyundecylenic acid (PEUDA).
  • the polyester resin serves to improve the adhesion of the composition, in particular to steel substrates, at temperatures above 70-80°C and also increase the storage stability of the reactive hotmelt granulate at room temperature.
  • the polyester is used in an amount of from 5 to 20 weight %, most preferably 5 to 10 weight %
  • the composition of the invention optionally also contains a filler.
  • the filler serves to decrease the tendency of the molten material to form threads and tails when the molten material is applied to a surface by extrusion. Certain fillers can also increase the viscosity at low shear rates by producing a thixotropic effect.
  • the filler may preferably be employed in an amount of from 0 % to 40 %, more preferably from 0 % to 25 %, and most preferably from 0 to 15 %, by weight, based on the total composition.
  • the filler is typically an inorganic mineral, such as calcium carbonate, magnesium silicate (talc), or calcium silicate (wollastonite).
  • Suitable fillers are precipitated calcium carbonate or ground calcium carbonate, magnesium silicate, and calcium silicate.
  • compositions of the above type have been found to have good initial adhesion properties to steel, particularly oily steel, whilst being capable of formulation into pellets which can be conveniently handled. They can be easily melted and applied, using conventional extrusion apparatus.
  • compositions of the present invention are useful as RHMAs, in particular as adhesives for oily steel parts in car assembly plants, and have the advantage that because they are solids ad ambient temperatures, they maybe shipped and stored in a more convenient manner than conventional liquid or pasty resins.
  • a method of preparing a reactive hot melt composition comprising compounding together a solid epoxy resin, and at least one random inte ⁇ olymer of ethylene as described above, together with, if desired, one or more of the optional additional ingredients referred to above.
  • the compounded composition may be pelletised to produce a dry free-flowing material.
  • the composition may generally be prepared by compounding the ingredients using any conventional form of compounding apparatus, for example single screw extruders, twin screw extruders, planetary extruders, ring extruders, batch internal mixers, kneaders or mixers such as those sold by Banbury, Farrell, Buss, or Kobe.
  • the mixing process preferably has a maximum processing temperature of less that 150°C, more preferably less than 130°C and a mixing time of less than 5 minutes, more preferably less than 2 minutes.
  • the processing temperature and mixing time are important to ensure that the epoxy resin has not been activated during the production of the RHMA composition.
  • all of the components with the exception of the curing agent can be compounded initially to form a pre-blend and then the curing agent may be added separately in a hotmelt extrusion or hot melt film extrusion step.
  • the more preferable method of producing the reactive hot melt adhesive is by compounding all of the ingredients together at process conditions such that the curing reaction does not take place until a the heat activation step.
  • the ingredients are melt blended and compounded in a Twin Screw Extruder (TSE) with a residence times of less than two minutes in the extruder and subsequently pelletised under water using a GalaTM Underwater granulator.
  • TSE Twin Screw Extruder
  • compositions according to the invention generally have excellent shelf life, and can be processed as hotmelt adhesives in a hotmelt extruder or extruded into a reactive hotmelt film at temperatures above the melting point of the composition (typically 90°C) and below the cure activation temperature of the composition (typically 180°C). Extruding the reactive composition at a temperature below the normal curing temperature of the composition minimizes the amount of curing that takes place during extrusion.
  • the extruded adhesive bead or film can be applied at a higher temperature than the curing temperature, causing the adhesive to cure.
  • Pelletised compositions of the present invention are free flowing at room temperature but may be transported in large containers, in which temperatures can reach 40 to 50 °C. In order to improve the free-flowing properties of the pellets, it may be desirable to apply a coating.
  • the pellet coating is preferably a powder coating comprising the filler, applied to the composition in an amount of from 0.2 to 2.0 % based on the weight of the composition.
  • an anti-cluster additive maybe inco ⁇ orated in the water into which the pellets are extruded.
  • the water additive may be a siloxane oil (for example those supplied under the trade Marks DC290 or DC200/350 from Dow Corning), an oxyalkylate (for example EC9092ATM from Nalco Exxon) or a water dispersion of polyethylene (for example Hordammer PE 03TM from Hoechst).
  • siloxane oil for example those supplied under the trade Marks DC290 or DC200/350 from Dow Corning
  • oxyalkylate for example EC9092ATM from Nalco Exxon
  • a water dispersion of polyethylene for example Hordammer PE 03TM from Hoechst.
  • the composition may be processed to form a film, for example by melt compounding the ingredients using an extruder fitted with a film die. The entire mix is melt blended and extruded directly into reactive hotmelt film. As before, the resulting film can be applied onto steel as steel coating and stored prior to use in a particular application.
  • Granules and films of the present invention are non blocking and storage stable.
  • storage stable it is meant that the granules can be stored at room temperature (22.2°C (72°F), 50 percent relative humidity) for long periods of time until needed in a particular application, without spontaneously blocking or curing.
  • a method of adhering a first component to a second component comprising the steps of melting a composition as described above, contacting the first and second components with the melted composition to form an initial bond between the components; and applying heat to cure the composition.
  • the composition is applied to a substrate at a temperature of from 110 to 140°C and is cured at a temperature above 140 °C, preferably above 180 °C for a time of more than 5 minutes.
  • the composition of the present invention is preferably applied to a substrate by means of an applicator which limits the temperature and time exposure of the composition as the composition is applied to the substrate.
  • an applicator which limits the temperature and time exposure of the composition as the composition is applied to the substrate.
  • Conventional RHMA equipment can be used if the temperature of application is less than 150°C, preferably less than 130°C and the time at the temperature of application is less than 10 minutes, preferably less than 3 minutes.
  • a preferred application system uses a heated pumping screw equipped with an accumulator which feeds the RHMA directly onto the substrate.
  • the compositions of the present invention When cured the compositions of the present invention generally have excellent Lap Shear Strength (LSS) (measured according to DIN EN 1465) and a strong cohesive bond strength, particularly with steel or aluminium, as determined by 180° peel strength (measured according to DIN 53282). This test is generally referred to herein as "T-Peel" strength).
  • LSS Lap Shear Strength
  • T-Peel This test is generally referred to herein as "T-Peel” strength.
  • the preferred compositions according to the invention after curing at 190 to 200°C for between 5 and 20 minutes, can achieve LSS values of from 4 to 30 MPa and T-Peel strengths of from 3.5 to 10 N/mm.
  • the cured adhesive can also provide desirable characteristics such as excellent temperature and chemical resistance, and excellent dimensional stability.
  • the uncured adhesive bead or film exhibits significantly excellent "green strength” and “melt strength” at application temperatures, which prevents adhesive bleed through.
  • green strength and the phrase “melt strength” refer to an adhesive 's bond strength and dimensional stability respectively while still in a molten state.
  • Adhesive beads or films of the present invention can be used to bond two pieces of steel together or bond aluminium with steel or other metals in car body construction replacing or partially replacing hem flanges and welding operations.
  • compositions according to the invention were prepared by compounding the components shown in Table 1, in a Twin Screw Extruder (TSE) at melt temperature of 110 to 120°C with a residence time of less than two minutes, and subsequently pelletising the composition using a GalaTM Underwater granulator.
  • TSE Twin Screw Extruder
  • compositions were processed to produce granular adhesives, having a granular particle size 2-3mm.
  • the compositions were storage stable at temperatures of up to 30°C without blocking or becoming sticky. They could however be melted, by heating to temperatures of approximately 100°C and applied onto steel as a hotmelt adhesive and subsequently adhere steel panels before and after curing as shown in Table 2.
  • Table 2 shows the Yield (MPa), the Elongation (%) and the T-peel strength (N/mm) before curing and T-peel strength (N/mm) and Lapshear strength (MPa) after curing.
  • T-peel The adhesive properties ("T-peel” strength) of the compositions of Examples 1 to 6 were tested according to DIN 53253, before and after oven curing at 200°C for 20 minutes.
  • Lap shear test degreased steel samples were used and the shear strength test was performed at lOmm/minute.
  • the polymer adhesive film was 1-1.5mm thick, 25 mm wide and bond line length was 10mm. Samples are cured at 200°C for 30 minutes to obtain bond line thickness of 0.5mm. The results are reported as force in Newtons/surface area.
  • T-peel test again degreased steel samples were used and a peel rate of lOmm/minute.
  • the polymer adhesive film was 1- 1.5mm thick, 25 mm wide and bond line length was 10mm. Samples are pre-cured at 200°C for 5 minutes and post cured at 200°C for 20 minutes to obtain final bond line thickness of 0.5 mm. The results are reported as force in Newton/bond line length.

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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)
  • Adhesives Or Adhesive Processes (AREA)

Abstract

Cette invention concerne une composition thermofusible réactive dont le point de ramollissement est d'au moins 50 °C, comprenant: une résine époxy dont le point de ramollissement est d'au moins 50 °C ; un interpolymère aléatoire d'éthylène et au moins comonomère d'acide carboxylique oléfiniquement insaturé, un comonomère d'ester d'acide carboxylique oléfiniquement insaturé, ou un comonomère d'ester de vinyle. La résine époxy est telle qu'il est possible de faire adhérer la composition sur une surface en la chauffant à une température d'application supérieure au point de ramollissement de manière à obtenir une composition adhésive fondue. Cette composition peut ensuite être durcie par chauffage à une température de durcissement destinée à faire se durcir la résine époxy, la température de durcissement étant supérieure à la température d'application. L'invention concerne également des procédés de fabrication de la composition, ainsi qu'un procédé de fixation d'un premier composant sur un second composant au moyen de cette composition.
PCT/EP2004/012476 2003-11-11 2004-11-04 Adhésif thermofusible réactif WO2005047393A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP03257084.8 2003-11-11
EP03257084 2003-11-11

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WO2005047393A1 true WO2005047393A1 (fr) 2005-05-26

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011087834A1 (de) * 2011-12-06 2013-06-06 Henkel Ag & Co. Kgaa Reaktive 2K-Schmelzklebstoffzusammensetzung
WO2013091575A1 (fr) * 2011-12-22 2013-06-27 Dow Global Technologies Llc Compositions et procédés de production de polyoléfines réticulées
US20140127499A1 (en) * 2012-11-02 2014-05-08 Ashland Licensing And Intellectual Property Llc Two Part Primer Composition
US9096039B2 (en) 2010-03-04 2015-08-04 Zephyros, Inc. Structural composite laminates
US9427902B2 (en) 2009-09-15 2016-08-30 Zephyros, Inc. Cavity filling
WO2017000121A1 (fr) * 2015-06-29 2017-01-05 Dow Global Technologies Llc Compositions et procédés de préparation de polyoléfines réticulées avec un initiateur de type peroxyde
US9688050B2 (en) 2004-06-18 2017-06-27 Zephyros, Inc. Panel structure
US10577523B2 (en) 2013-07-26 2020-03-03 Zephyros, Inc. Relating to thermosetting adhesive films
US11028220B2 (en) 2014-10-10 2021-06-08 Zephyros, Inc. Relating to structural adhesives
US11248145B2 (en) 2008-04-09 2022-02-15 Zephyros, Inc. Structural adhesives

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US4517340A (en) * 1982-08-25 1985-05-14 Raychem Corporation Adhesive composition
EP0343676A2 (fr) * 1988-05-27 1989-11-29 Teroson Gmbh Adhésif structurel réactif s'appliquant à chaud
US5242980A (en) * 1990-02-06 1993-09-07 Exxon Chemical Patents Inc. Ethylene-unsaturated alcohol or acid copolymer and epoxy crosslinker
WO2002050184A2 (fr) * 2000-12-20 2002-06-27 Dow Gloval Technologies Inc Compositions pour amortir des vibrations

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Publication number Priority date Publication date Assignee Title
US4517340A (en) * 1982-08-25 1985-05-14 Raychem Corporation Adhesive composition
EP0343676A2 (fr) * 1988-05-27 1989-11-29 Teroson Gmbh Adhésif structurel réactif s'appliquant à chaud
US5242980A (en) * 1990-02-06 1993-09-07 Exxon Chemical Patents Inc. Ethylene-unsaturated alcohol or acid copolymer and epoxy crosslinker
WO2002050184A2 (fr) * 2000-12-20 2002-06-27 Dow Gloval Technologies Inc Compositions pour amortir des vibrations

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10647083B2 (en) 2004-06-18 2020-05-12 Zephyros, Inc. Panel structure
US9688050B2 (en) 2004-06-18 2017-06-27 Zephyros, Inc. Panel structure
US11248145B2 (en) 2008-04-09 2022-02-15 Zephyros, Inc. Structural adhesives
US11667813B2 (en) 2008-04-09 2023-06-06 Zephyros, Inc. Structural adhesives
US9427902B2 (en) 2009-09-15 2016-08-30 Zephyros, Inc. Cavity filling
US9096039B2 (en) 2010-03-04 2015-08-04 Zephyros, Inc. Structural composite laminates
DE102011087834A1 (de) * 2011-12-06 2013-06-06 Henkel Ag & Co. Kgaa Reaktive 2K-Schmelzklebstoffzusammensetzung
WO2013091575A1 (fr) * 2011-12-22 2013-06-27 Dow Global Technologies Llc Compositions et procédés de production de polyoléfines réticulées
CN104115239A (zh) * 2011-12-22 2014-10-22 陶氏环球技术有限责任公司 用于制备交联的聚烯烃的组合物和方法
US20140127499A1 (en) * 2012-11-02 2014-05-08 Ashland Licensing And Intellectual Property Llc Two Part Primer Composition
US11873428B2 (en) 2013-07-26 2024-01-16 Zephyros, Inc. Thermosetting adhesive films
US10577522B2 (en) 2013-07-26 2020-03-03 Zephyros, Inc. Thermosetting adhesive films including a fibrous carrier
US10577523B2 (en) 2013-07-26 2020-03-03 Zephyros, Inc. Relating to thermosetting adhesive films
US11028220B2 (en) 2014-10-10 2021-06-08 Zephyros, Inc. Relating to structural adhesives
CN107709444A (zh) * 2015-06-29 2018-02-16 陶氏环球技术有限责任公司 用过氧化物引发剂制备交联的聚烯烃的组合物和方法
CN107709444B (zh) * 2015-06-29 2021-06-11 陶氏环球技术有限责任公司 用过氧化物引发剂制备交联的聚烯烃的组合物和方法
US10703890B2 (en) 2015-06-29 2020-07-07 Dow Global Technologies Llc Compositions and methods for making crosslinked polyolefins with peroxide initiator
WO2017000121A1 (fr) * 2015-06-29 2017-01-05 Dow Global Technologies Llc Compositions et procédés de préparation de polyoléfines réticulées avec un initiateur de type peroxyde

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