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
  • C09J5/00—Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers
  • C09J5/02—Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers involving pretreatment of the surfaces to be joined
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/28—Surface treatment of glass, not in the form of fibres or filaments, by coating with organic material
  • C03C17/30—Surface treatment of glass, not in the form of fibres or filaments, by coating with organic material with silicon-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/28—Surface treatment of glass, not in the form of fibres or filaments, by coating with organic material
  • C03C17/32—Surface treatment of glass, not in the form of fibres or filaments, by coating with organic material with synthetic or natural resins
  • C03C17/322—Polyurethanes or polyisocyanates
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/28—Surface treatment of glass, not in the form of fibres or filaments, by coating with organic material
  • C03C17/32—Surface treatment of glass, not in the form of fibres or filaments, by coating with organic material with synthetic or natural resins
  • C03C17/328—Polyolefins
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/34—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions
  • C03C17/3405—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions with at least two coatings of organic materials
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L11/00—Compositions of homopolymers or copolymers of chloroprene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L15/00—Compositions of rubber derivatives
  • C08L15/02—Rubber derivatives containing halogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/26—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers modified by chemical after-treatment
  • C08L23/28—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers modified by chemical after-treatment by reaction with halogens or compounds containing halogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2312/00—Crosslinking
  • C08L2312/08—Crosslinking by silane
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
  • C08L61/20—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen
  • C08L61/26—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds
  • C08L61/28—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds with melamine
• • 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
  • C09J2423/00—Presence of polyolefin
• • 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
  • C09J2461/00—Presence of condensation polymers of aldehydes or ketones

Definitions

• the present invention relates to a method for bonding a thermoplastic vulcanizate (TPV) to glass, metal or painted metal surfaces.
• the method of the invention allows to bond TPV to the surface of glass substrates in the manufacture of automotive windshields, rear windows or quarter-lights that comprise a glass substrate and a TPV.
• encapsulation means that the glass is placed in a steel or aluminum mould, the mold is closed and then the polymer is injected into the cavity of the mold.
• the encapsulation of glass is performed by injection molding or robotic extrusion, as described in United States Patent No. 5,336,349, using thermoplastic vulcanizates (TPV) such as Santoprene ® rubbers and suitable adhesion promoting compositions.
• TPV thermoplastic vulcanizates
• One alternative of improving the adhesion of vinyl polymers to glass surfaces is disclosed in United States Patent No. 3,998,985 which relates to the incorporation of certain polyaminosilane compounds into the vinyl polymer to be bonded.
• the vinyl polymer is mixed with a combination of a polyaminosilane and a primer that contains an epichlorohydrin-bisphenol A resin, N-aminoethyl-gamma- aminopropyltrimethoxysilane, ethyleneglycolmono-methylether, and ethyleneglycolmonoethylether acetate.
• vinyl polymer-glass adhesives are disclosed in United States Patent No. 3,666,539 that discloses epoxy reactive silanes which act as coupling agents for adhering various polymers to glass; United States Patent No. 3,362,843 that discloses a mixture of an aminoalkylalkoxysilane and an epoxy resin-methyl methacrylate primer; and United States Patent No. 3,734,763 that discloses the use of N-[beta-(N'- para-vinylbenzyI) - aminoethyl] -gamma-amino- propyltrimethoxysilane hydrochloride as a vinyl polymer-glass coupling agent.
• Polyurethane adhesive systems are commonly used to promote adhesion between glass surfaces of automotive windscreens, side windows, etc. and the surrounding TPV seals are known from United States Patent No. 5,336,349.
• United States Patent Nos. 5,102,937 and 5,051 ,474 disclose formulations useful as coating, primer or adhesive including a linear polyester polyurethane, a halogenated polyolefin, an alkoxy silane compound, and a cross-linker.
• the formulations are preferably utilized as two-component adhesive for bonding vinyl polymers such as polyvinyl chloride or thermoplastic elastomers to various substrates such as glass or metal.
• United States Patent No. 5,102,937 discloses an adhesive composition for bonding vinyl compounds to glass substrates.
• the adhesive com position comprises a crosslinkable polyester polyurethane, a halogenated polyolefin, an alkoxy silane primer and an isocyanate crosslinker.
• Japanese published patent application JP-10-158619 discloses an adhesive composition comprising a crosslinkable acrylic resin, a chlorinated polypropylene and a polyisocyanate crosslinking agent.
• Japanese published patent application JP-55-018462 discloses an adhesive composition comprising a crosslinkable EVA or acrylic resin, a chlorinated polypropylene and an isocyanate crosslinker.
• Japanese published patent application JP-60- 135471 discloses an adhesive latex composition com prising a crosslinkable melamine resin, a polychloroprene latex and an isocyanate crosslinker.
• UV-stabilizers are commonly added to the TPV compositions.
• Sterically hindered amines that are known in the prior art by the abbreviation HALS (hindered amine light stabilizer) have been established as suitable light stabilizers for TPV gaskets that are applied, for example, to an automobile glazing as a frame along its border.
• HALS hindered amine light stabilizer
• polyurethane based adhesive systems suffer from the substantial drawback to react with moisture (penetrating, for instance, the TPV matrix under humid conditions) and/or with the am ine-groups of the above-mentioned HALS stabilizers. This interaction often results in complete bonding failures.
• HALS stabilizers that are extracted from the TPV result in alkaline solutions that may cause further adhesion problems, i.e., by cleavage of the urethane bond.
• thermoplastic vulcanizate to a glass surface that obviates the above disadvantages and drawbacks, i.e., a method involving an adhesion promoting com position that is less sensitive to moisture and that shows a high com patibility with HALS.
• the object of improving adhesion between TPV and glass surfaces has been solved by a method of bonding a TPV to the surface a glass substrate said method comprising the steps of: (I) applying a silane primer to the glass surface, (II) applying an adhesive composition comprising (A) a halogenated polyolefin; ( B) a crosslinkable resin; and (C) an isocyanate crosslinker, on top of the primer; and (II I) applying the TPV to the treated surface.
• the invention relates to a method of bonding a TPV to the surface a glass substrate said method comprising the steps of: (I) applying an adhesive composition comprising: (A) a halogenated polyolefin; (B) a crosslinkable resin; and (C) an isocyanate crosslinker; and (D) a silane primer; to the glass surface; (II) applying said TPV to the treated surface.
• an adhesive composition comprising: (A) a halogenated polyolefin; (B) a crosslinkable resin; and (C) an isocyanate crosslinker; and (D) a silane primer; to the glass surface; (II) applying said TPV to the treated surface.
• the silane primer can be applied to the glass surface or, alternatively, it can be contained in the adhesive composition.
• the silane primer can be present on the glass surface and in the adhesive composition.
• the composite structure obtainable by said method comprises a glass substrate, a thermoplastic vulcanizate, and an adhesive arranged between the glass substrate and the thermoplastic vulcanizate, wherein the adhesive comprises is as defined above.
• Typical articles of manufacture are those in which a thermoplastic vulcanizate is to be reliably adhered to a glass surface such as in the field of making automotive or aerospace parts, for instance, automotive windshields, side windows, rear windows, quarter lights, aircraft windows, and the like.
• adhesive composition and adhesion promoting composition are used interchangeably.
• composition used in the method of the invention comprising the halogenated and optionally maleated polyolefin, the crosslinkable resin and the isocyanate crosslinker represents an excellent adhesive for bonding a thermoplastic vulcanizate to a glass surface.
• the adhesion promoting composition according to the present invention leads to improved bond strength combined with excellent retention of properties over a long period of time, even if TPVs that are stabilized by carbon black and/or organic stabilizers, such as HALS, are used.
• thermoplastic vulcanizate to be adhered to a glass surface using the adhesive composition of the present invention has a combination of both thermoplastic and elastic properties (thermoplastic elastomers; TPE) .
• Thermoplastic vulcanizates are generally obtained by blending a thermoplastic polyolefin with an elastomeric composition (rubber) in a way such that the elastomer is intimately and uniformly dispersed as a discrete particulate phase within a continuous phase of the thermoplastic polyolefin.
• thermoplastic elastomer vulcanizate TPV
• TPV thermoplastic elastomer vulcanizate
• the thermoplastic rubber component (A) may generally be prepared by mixing (a) an uncured rubber, and (b) a thermoplastic polyolefin homopolymer or copolymer and; optionally (c) conventional additives and fillers; melting the mixture under high shear such as kneading until a homogeneous blend is obtained.
• curing agents also referred to as curatives, crosslinking- or vulcanizing agents
• a fully cured also referred to as fully vulcanized or fully crosslinked
• rubber as used herein means any natural or synthetic polymer which can be cured so as to exhibit elastomeric properties.
• elastomer is used interchangeably with the term “rubber”.
• thermoplastic vulcanizate (TPV) thermoplastic vulcanizate
• thermoplastic elastomer thermoplastic elastomer
• thermoplastic rubber thermoplastic rubber
• UV stabilized TPVs comprise stabilizers selected from heat stabilizers, acid scavengers and/or sterically hindered amine stabilizers (HALS) .
• HALS sterically hindered amine stabilizers
• a combination of low molecular HALS that can migrate easier to the surface, such as Tinuvin ® 770, supplied by Ciba Special Chemicals and high molecular HALS, which are more strongly bond to the TPV, such as Chimasorb ® , supplied by Ciba Special Chemicals are used.
• glass used in conjunction with the present invention is meant to relate to any substrate or surface of glass, ceramics, enamel, silicate (coated on plastics or metals) and other silicate containing products such as clay or concrete.
• the adhesive composition used according to the present invention comprises a halogenated polyolefin, preferably chlorinated polyolefin.
• Halogenated polyolefinic materials which are suitable in accordance with the present invention may be generally described as halogenated alpha-mono- olefin polymers having optionally maleic acid groups grafted thereon. Additionally, the halogenated and/or maleated polyolefinic compounds may also be substituted by halosulfonyl groups.
• the halo-substituent may be any of the halogens selected from the group consisting of fluorine, chlorine, bromine and iodine with chlorine being especially preferred.
• specific olefin polymeric materials that fall within the above group of halogenated/maleated polyolefins and that may be employed in the compositions of the present invention may also include chlorosulfonated polymers of ethylene, propylene, isobutylene and the like, chlorinated natural rubber, chlorine- and bromine-containing synthetic rubbers and halogenated polymers derived from dienes having from 4 to 8 carbon atoms, preferably 5 to 7 and most preferred 6 carbon atoms.
• halogenated polyolefins are selected from the group consisting of polychloroprene, chlorinated polychloroprene, chlorinated polypropylene, chlorinated polybutadiene, chlorinated polyisoprene, halogenated polybutylene, halogenated polyhexadiene, chlorinated butadiene styrene copolymers, chlorinated ethylene propylene copolymers and chlorinated ethylene/propylene/non-conjugated diene terpolymers, chlorinated polyethylene, chlorosulfonated polyethylene, halogenated copolymers of alpha-olefins of containing 2 to 8 carbon atoms, preferably 3 to 7 carbon atoms, chlorinated poly(vinyl chloride), and mixtures thereof, and the like, including mixtures of such halogen-containing polymers.
• the halogenated polyolefin of the first component can also be a halogenated vinyl halide polymer including halogenated homopolymers or copolymers of vinyl halide.
• substantially any of the known halogen-containing derivatives of natural and synthetic elastomers can be employed as the halogenated polyolefin in the practice of this invention, including mixtures of such polymers.
• the halogen content of the halogenated polyolefin is from about 5wt .-% to about 50 wt.-%, preferably from about 20 wt.-% to about 30 wt.-% and most preferably about 25 wt.-% .
• Chlorinated and maleated polyolefins i.e. polyolefins that are both chlorinated and grafted with maleic acid (MA) and/or maleic acid anhydride (MAH) are especially preferred.
• Chlorinated and maleated polypropylenes CI-MAH-gr- PP are especially preferred as the constituent of the adhesive compositions used according to the present invention.
• I n an alternative and preferred embodiment there is used chlorinated/maleated polypropylene based on isotactic low molecular weight polypropylenes as described by form ula I
• x is an integer from about 20 to about 500, preferably from about 30 to about 400, most preferably from about 40 to about 300.
• These polymers have an average molecular weight (M w ) of from about 20,000 to about 120,000, preferably from about 30,000 to about 1 10,000, more preferably from about 40,000 to about 100,000.
• the chlorine content of the chlorinated/maleated polypropylene is from about 15 to about 35 wt.-% , preferably from about 18 to about 32 wt.-% and more preferably from about 20 to about 30 wt.-%
• the content of maleic acid anhydride is from about 0.5 to about 5.0 wt.-% , preferably from about 1 to about 3.0 wt .-% and more preferably from about 1 .5 to about 2.0 wt .-%.
• Suitable chlorinated and/or maleated polypropylenes are commercially available from Tramaco under the trade designation Trapylene ® 803 LS, 196S, 130X, 135X and 822X or from Siber Hegner under the trade designations Hardlen ® 13MLJ, 15 LP and CY-9122P.
• the adhesive composition used according to the present invention comprises from about 5wt .-% to about 95 wt.-% , preferably from about 25 wt.-% to about 75 wt.-% , most preferably from about 35 wt.-% to about 55 wt.-% of the halogenated polyolefin, based upon the total weight of the adhesive composition comprising the halogenated polyolefin (A), the crosslinkable resin (B), and the isocyanate crosslinker (C) .
• Crosslinkable Resin (B) A further constituent of the adhesive composition used according to the present invention is a crosslinkable resin.
• Crosslinkable resins are polymeric compounds having functional groups that are able to react with the isocyanate group of the isocyanate crosslinking agent (C) .
• the crosslinkable resin may be represented by com pounds obtainable by the reaction of melamines, urea, benzoguanamine, glycoluril or mixtures thereof with formaldehyde.
• epoxy- and/or acrylic resins can be used as ⁇ osslinkable resins (B) according to the present invention.
• melamine resins are used as crosslinkable resins (B).
• Preferred melam ine resins are selected from the group consisting of hexamethoxymethylmelamine resins, high solids methylated melamine resins, high solids mixed ether melamine resins and butylated melamine resins, wherein hexamethoxymethylmelamine (HMMA) resins are highly preferred.
• HMMA hexamethoxymethylmelamine
• “High solids” means that the solid content is generally above 70 to 98 wt.-%, based on organic volatile m easurements.
• Said crosslinkable resins (B) are commercially available, for instance, from SOLUTIA under the trade designation Resimene ® or from CYTEC under the trade designation Cym el ® .
• the hexamethoxymethylmelamine resins Resimene ® 745 and Resimene ® 3521 are used.
• acrylic resins having crosslinkable hydroxyl groups may be used as the crosslinkable resin ( B) .
• Acrylic resins that can be used according to the present invention are available by polymerizing monomers which contain a vinyl group and which may be described as resinous polymers of esters of alpha, beta-ethylenically unsaturated monocarboxylic acids and saturated aliphatic alcohols containing from 1 to about 10 carbon atoms, preferably from 1 to 8 carbon atoms, more preferably from 2 to 6 carbon atoms.
• the monomers from which these esters are obtained may be described by the following general formula I I
• R and R 1 independently represent hydrogen or alkyl groups, preferably methyl, or straight or branched chain alkyl groups having up to 10 carbon atoms, preferably from 1 to 8 carbon atoms, more preferred from 2 to 6 carbon atoms
• Ff is a straight or branched alkyl group having up to 10 carbon atoms, preferably from 1 to 8 carbon atoms, more preferred from 2 to 6 carbon atoms.
• acrylic resins having a crosslinkable hydroxyl group are especially preferred.
• Such acrylates are commercially available from SOLUTIA under the trade designation Macrynal ® SM540/60X. Compared to the melamine resins the use of acrylic resins leads to adhesion promoting compositions which are more sensitive to moisture.
• epoxy resins having crosslinkable groups may be used as crosslinkable resins (B) .
• Epoxy resins are prepolymers that contain on the average two or more epoxide groups per molecule. Their reaction with a variety of curing agents, for instance, with diols, such as bisphenol A leads to cross-linked or thermoset plastics with excellent strength, toughness and chemical resistance.
• Suitable epoxy resins are known from the prior art and are commercially available. For instance there can be used D.E.R. ® , D.E.N.
• Araldite GT6097CH ® supplied by Ciba Geigy is used.
• the adhesive composition according to the present invention co prises about 10 wt.-% to about 60 wt.-% , preferably about 15 wt.-% to about 50 wt.-%, most preferably about 20 wt.-% to about 30 wt.-% of the crosslinkable resin (B), based upon the total weight of the chlorinated polyolefin (A), crosslinkable resin (B) and the isocyanate crosslinker (C) .
• the adhesive composition used according to the present invention further comprises an isocyanate crosslinking agent that is capable of reacting with both the functional groups of cross- linkable resin (B) and with the silane primer (iii) comprised in the adhesion system used according to the present invention.
• any diisocyanate having two reactive isocyanate groups can be used in order to react with the hydroxyl groups of the acrylic or epoxy resin or the amino group of the melamine resin.
• Exemplary representative diisocyanates are typically selected from diisocyanates such as 1 ,6 - hexamethylene diisocyanate, 1 ,8 -octomethylene diisocyanate, 1 , 12- dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate and sim ilar isocyanates, 3,3'-diisocyanatodipropyl ether, 3- isocyanatomethyl-3,5,5'-trimethylcyclohexyl isocyanate, cyclopentalene- 1 ,3-diisocyanate, cyclohexylene- 1 ,4-diisocyanate, methyl-2,6- diisocyanatocaprolate, bis-(2- isocyanatoethyl)
• blocked isocyanates having reduced reactivity compared to unblocked diisocyanate are used as crosslinking agents (C) . Due to the low reactivity of the blocked isocyanates the adhesion promoting compositions of the present invention have significantly increased open times and improved storability.
• Blocked isocyanates which are preferably used in conjunction with the present invention are based on isophorone diisocyanate (3-isocyanatomethyl-3,5,5 - trimethylcyclohexyl isocyanate; I PDI) and supplied by Degussa under the trade designations Vestanat ® I PDI and Vestanat ® T 1890/1 00.
• the adhesive composition typically comprises the isocyanate crosslinker in an amount of about 10 wt.-% to about 60 wt.-%, preferably about 15 wt.-% to about 50 wt.-% , most preferably about 25 wt.-% to about 30 wt.-% , based upon the total weight of the adhesive composition comprising the chlorinated polyolefin (A), the crosslinkable resin (B) and the isocyanate crosslinker (C) .
• the adhesion system used according to the invention can further comprise a silane primer that is applied to the glass surface to which the TPV is to be adhered. Therefore, primers that can be used in conjunction with the adhesion promoting composition of the present invention have to be capable of interacting with both the glass surface and the functional groups of the isocyanate crosslinker (C) and/or with the crosslinkable resin (B) .
• the silane primer is selected from the group consisting of epoxy-silanes of formula (III), mercapto-silanes of formula (IV) and amino-silanes of formula (V) as shown herein below:
• n, m and p are integers from 1 to 12, preferably 2 to 8, more preferably 3 to 5 and the substituents R 3 to R 11 are each individually selected from linear and branched alkyl groups having from 1 to 12, preferably from 2 to 8, most preferably 3 to 4 carbon atoms and substituents R 12 and R 13 are independently selected from hydrogen and linear and branched alkyl groups having from 1 to 12, preferably from 2 to 8, most preferably 3 to 4 carbon atoms, preferably R 12 and F are both hydrogen.
• the silane primer is a compound selected from the group consisting of 3-aminopropyl- triethoxysilane and 3-mercaptopropyl-triethoxysilane which are supplied by Sivento under the trade names Dynasylan ® 3201, Dynasylan ® AMEO.
• a further silane primer is 3-glycidyloxypropyl-trimethoxysilane commercially available from Sivento under the trade designation Dynasylan ® GLYMO.
• suitable silane primers are commercially available from DOW Chemical under the trade designation Betawipe VP ® 046404, from SI KA under the trade designation Sika ® -Activator and from Teroson under the designation Terostat ® -8540.
• the silane primers may be dissolved in suitable solvents such as alcohols, preferably ethanol, methanol, n- or isopropanol.
• a thin layer of the silane primer is applied to the glass surface to be adhered to the TPV.
• the primer is usually dissolved suitable in a solvent, such as methyl-, ethyl- or isopropyl alcohol to give a 1 to 5 wt.-% solution. That solution is then applied to the glass surface as thinly as possible by spraying, brushing or wiping.
• wipe on/wipe off techniques are used, wherein the applied film is wiped off immediately after its application.
• the wet coating thickness of the primer is in the range of about 0.3 ⁇ m to about 5 ⁇ m , preferably about 0.5 ⁇ m to about 3 ⁇ m, most preferably about 0.8 ⁇ m to about 2 ⁇ m .
• the silane primer is admixed with the adhesion promoting composition.
• the application of the primer to the glass surface simultaneously occurs with the adhesive composition and, as a consequence, a separate coating step is redundant.
• the adhesive composition according to the invention is prepared by admixing the chlorinated polyolefin (A) , the crosslinkable resin (B) , the isocyanate crosslinker (C) and, in the alternative embodiment of the invention described above, the silane primer.
• an organic solvent is used in order to facilitate mixing of the compounds and application of the adhesion promoting composition.
• solvents suitable for the adhesion promoting com position are selected from polar and aromatic organic solvents such as n-butylacetate, benzene, tetrahydrofurane, trichloroethane, trichloroethylene, dichloromethane, methylene chloride, xylene and toluene, with toluene being preferred.
• the silane primer may be present in said solution in an amount of from about 0.1 wt.-% to about 5 wt.-% , preferably from about 0.5 wt.-% and 2.5 wt.-% , most preferably from about 0.7 wt.-% and 1 .2 wt.-% , based on the total weight of the solution.
• the solvent is utilized in an am ount sufficient to provide a solution of the adhesion promoting composition having a total solids content (TSC) of about 5 wt.-% to about 30 wt.-% , preferably about 8 wt.-% to about 20 wt.-% , most preferably about 10 wt.-% to about 16 wt .-% .
• TSC total solids content
• the adhesive form ulation used according to the present invention may optionally contain other well-known and common additives including plasticizers, fillers, pigments, reinforcing agents, and the like, in amounts employed by those skilled in the art in order to obtain the desired color and consistency.
• the isocyanate crosslinker (C) is preferably stored separately from the precursor comprising the chlorinated and optionally maleated polyolefin (A) , the crosslinkable resin (B) and the silane primer. Prior to its application to the substrate the precursor and the crosslinker (C) are thoroughly m ixed in the amounts described above.
• the formulation is applied to the glass substrate immediately after mixing the components in order to avoid any increase in viscosity that might create problems associated with the corresponding application technique.
• the form ulation may be applied to a desired substrate by techniques commonly known in the art such as by wiping, brushing, spraying, or dipping the substrate with the form ulation.
• the form ulation is applied to the surface by spraying or brushing.
• the amount of adhesion promoting composition applied to the substrate surface is from about 5 to about 50 ⁇ m , preferably about 10 to about 40 ⁇ m , most preferably about 15 to about 30 ⁇ m, based upon the total adhesive (wet state) of the adhesion promoting composition
• the TPV is applied to the pre- coated glass surface using conventional state of the art injection molding, robotic extrusion or any other suitable method. If the adhesive composition has been dissolved in a solvent the formulation is dried for a time sufficient to evaporate the solvent prior to applying the TPV. After having applied the adhesive composition on top of the silane primer coating, or if the silane primer is comprised in the composition on top of the glass surface, the adhesive composition is dried by an air or a hot air stream .
• the TPV can be applied to the treated surface at room tem perature or, alternatively, at an elevated temperature.
• the glass surface prior to the application of the TPV the glass surface can be pre- heated to a tem perature of about 80 to about 100°C, preferably to about 85 to 95 °C, most preferably to about 90°C. Thereafter the TPV is applied to the pre- treated surface by injection molding, (robotic) extrusion as disclosed in United states Patent No. 5,336,349 the content which is fully incorporated by reference, laminating welding or any other method known in the art.
• injection molding, (robotic) extrusion as disclosed in United states Patent No. 5,336,349 the content which is fully incorporated by reference, laminating welding or any other method known in the art.
• the silane primer in the adhesion promoting composition can be the same or different from the silane primer used to pre-treat the glass surface.
• the method of the invention has proven beneficial when bonding TPV to the surface of glass substrates such as, for instance, in the manufacture of automotive and aerospace/aircraft windows such as windshields, rear windows or quarter-lights that comprise a glass substrate and a TPV.
• the methods of the invention and the compositions employed are likewise and without lim itation applicable to the bonding of TPV to metal substrates such as steel, zinc, copper, aluminum, chromium , nickel, lead, titan, silver, gold, platinum , metal alloys such as brass or bronze, and the respective painted metal substrates. Therefore the term “glass substrate” can interchangeably be used with the term “metal substrate” or “painted metal substrate” in this description and the appending claims.
• the adhesion force between glass and TPE has been determined by the Peel test according to ASTM D429B and DI N 53531 . Therefore, the glass/ ceramic surfaces have been cleaned with pure acetone and coated with a thin layer of Betawipe ® VP 04604 using a felt. After having dried the primer coating the adhesion promoting compositions as described in Table 1 were applied to the surface using a soft polyethylene foam sponge. After having completely dried the adhesion promoting composition Santoprene ® 121 - 50E500 rubber was coated to the surface by extrusion. The test samples were stored for 7 days at 23 °C. Then the init ial peel test (H-0) was performed.
• the bonded specimen was wrapped in a clean cellulose paper so that the edges were covered. The wrapped specimen was then put in a 1 liter polyethylene bag one third thereof being filled with demineralized water (the specimen must not have direct contact with the water) . After a 7 days storage at 70°C (H-7) the test specimen were removed from the plastic bags and cooled to room tem perature. Thereafter, peel tests as described above were performed. I n case of a cohesive rupture the tear occurs within the TPV whereas in case of adhesive rupture the TPV detaches from the glass surface with the TPV staying intact. The following Table summarizes the results obtained: TABLE

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