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
  • 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
  • C09J123/18—Homopolymers or copolymers of hydrocarbons having four or more carbon atoms
  • C09J123/20—Homopolymers or copolymers of hydrocarbons having four or more carbon atoms having four to nine carbon atoms
  • C09J123/22—Copolymers of isobutene; Butyl rubber ; Homo- or copolymers of other iso-olefines
• • 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
  • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F210/04—Monomers containing three or four carbon atoms
  • C08F210/08—Butenes
  • C08F210/10—Isobutene
• • 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
  • C08F8/00—Chemical modification by after-treatment
• • 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
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/30—Introducing nitrogen atoms or nitrogen-containing groups
  • C08F8/32—Introducing nitrogen atoms or nitrogen-containing groups by reaction with amines
• • 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
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/46—Reaction with unsaturated dicarboxylic acids or anhydrides thereof, e.g. maleinisation
• • 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
  • C09J123/26—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 modified by chemical after-treatment
• • 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
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
  • C09J7/21—Paper; Textile fabrics
• • 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
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
  • C09J7/22—Plastics; Metallised plastics
• • 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
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/35—Heat-activated
• • 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
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/38—Pressure-sensitive adhesives [PSA]
• • 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
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/38—Pressure-sensitive adhesives [PSA]
  • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • C09J7/383—Natural or synthetic rubber
• • 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
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/38—Pressure-sensitive adhesives [PSA]
  • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • C09J7/387—Block-copolymers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/28—Web or sheet containing structurally defined element or component and having an adhesive outermost layer
  • Y10T428/2809—Web or sheet containing structurally defined element or component and having an adhesive outermost layer including irradiated or wave energy treated component

Definitions

• This invention relates to pressure-sensitive adhesives and adhesive sealants prepared from isobutylene copolymers, and tape articles prepared therefrom.
• the pressure-sensitive adhesives are characterized by exhibiting an overall balance of adhesive and cohesive characteristics and exceptional adhesion to low surface-energy substrates.
• Pressure-sensitive tapes are virtually ubiquitous in the home and workplace.
• a pressure-sensitive tape comprises an adhesive and a backing, and the overall construction is tacky at the use temperature and adheres to a variety of substrates using only moderate pressure to form the bond.
• pressure- sensitive tapes constitute a complete, self-contained bonding system.
• PSAs pressure-sensitive adhesives
• Materials that have been found to function well as PSAs include polymers designed and formulated to exhibit the requisite viscoelastic properties resulting in a desired balance of tack, peel adhesion, and shear holding power.
• PSAs are characterized by being normally tacky at room temperature (e.g., 20°C). PSAs do not embrace compositions merely because they are sticky or adhere to a surface.
• high performance pressure-sensitive tapes are those capable of supporting loads at elevated temperatures for 10,000 minutes. Increased shear holding capability has generally been accomplished by crosslinking the PSA, although considerable care must be exercised so that high levels of tack and adhesion are retained in order to retain the aforementioned balance of properties.
• PSA pressure sensitive adhesive
• tack storage modulus of 3 x 10 6 dynes/cm 2 at room temperature and oscillation frequency of 1 Hz
• the material will not be tacky and is not useful by itself as a PSA material.
• low molecular weight, high T g resin polymers (tackifiers) or low molecular weight, low T g polymers (plasticizers) are often used to modulate the T g and modulus into an optimal PSA range.
• the adhesive (co)polymers of this disclosure comprise: a) an isobutylene copolymer having pendent, free-radically polymerizable, ethylenically unsaturated groups, b) a tackifier, and c) a crosslinking agent.
• the pressure-sensitive adhesive comprises the interpolymerized reaction product of isobutylene and at least one monomer having a pendent, free-radically polymerizable, ethylenically unsaturated group.
• the pressure-sensitive adhesives of this disclosure provide the desired balance of tack, peel adhesion, and shear holding power, and further conform to the Dahlquist criteria; i.e. the modulus of the adhesive at the application temperature, typically room temperature, is less than 3 x 10 6 dynes/cm at a frequency of 1 Hz.
• hot melt adhesive compositions are provided which applied to substrates from the melt. Such hot melt adhesive compositions are substantially solvent-free. Hot melt adhesives are versatile and widely used in industrial applications, such as bookbindings, cardboard boxes, plastic parts and wooden articles, among others. They are generally 100% solid adhesives with application temperatures which vary from about 150 to about 180°C,
• thermoplastics e.g., polyethylene, polypropylene, ethylene propylene diene monomer rubber (EPDM)
• EPDM ethylene propylene diene monomer rubber
• PSA pressure-sensitive adhesive
• PSA tapes are the easiest to use, but for the most part, pressure-sensitive adhesives do not adhere well to low surface energy substrates. Additionally, most PSAs are unsuited for uses requiring good internal (cohesive) strength at elevated temperatures. For example, rubber-resin PSAs tend to soften and degrade when heated. PSAs based on styrene-containing block copolymers also do not retain good internal strength when heated, because styrene has a low T g and so softens at moderately elevated temperatures.
• the bonding to low surface-energy surfaces is achieved by priming the substrate with polar liquid followed by application of PSAs. Even after this two step process, the existing PSAs do not fulfill customer requirements. There is need to develop primerless LSE PSAs at competitive cost but still with the most optimized properties.
• PIB polyisobutylene
• LSE low surface energy
• PIB-based materials have potential use in electronic and photovoltaic encapsulation applications.
• low cohesive strength of the material has limited the uses for high shear applications.
• Another possible application for PIB-based material is in the medical adhesive field.
• Most acrylate -based PSAs are not suitable for medical application since acrylate PSAs tend to give off toxic vapors at elevated temperatures.
• Acrylate-based PSAs typically contain monomeric materials which, even at ordinary room temperatures, exude odors that make acrylate PSA tapes generally unsuitable for medical uses.
• Polyisobutylene PSAs are often used for medical uses because they are physiologically inert, but again they tend to be deficient in internal strength.
• the adhesive compositions of the present disclosure provide an improved pressure- sensitive and hot-melt adhesive composition which may be adhered to a variety of substrates, including low surface-energy (LSE) substrates, within a wide temperature range and provide good adhesive strength and holding characteristics.
• the adhesive compositions are easily handled, and are environmentally friendly due to the low volatile organic compound (VOC) content, such as solvents.
• the adhesive compositions of the present disclosure further provide a pressure-sensitive adhesive article, such as adhesive tapes and sealants.
• the adhesive copolymer comprises an isobutylene copolymer having pendent, free-radically polymerizable, ethylenically unsaturated groups, b) a tackifier, and c) a photocrosslinking agent.
• the pressure-sensitive adhesive comprises the interpolymerized reaction product of isobutylene and at least one monomer having pendent, free-radically polymerizable, ethylenically unsaturated group(s), including alkenyl, allyl and vinyl groups.
• the monomer having pendent, free-radically polymerizable, ethylenically unsaturated groups may be derived from halogenated butyl rubber and is of the general formula:
• Q is a multivalent, preferably divalent linking group and Z is a pendent, free- radically polymerizable, ethylenically unsaturated group and R 7 is H or C3 ⁇ 4. More particularly, the isobutylene copolymer may be of the formula;
• a is at least 20, and at least one of b and c are at least one, Q is a polyvalent linking group and Z is a pendent, free-radically polymerizable, ethylenically unsaturated group; or
• a and d are at least 1, preferably a is at least 20, d is at least one, R is H or CH 3 , Q is a polyvalent linking group and Z is a pendent, free-radically polymerizable, ethylenically unsaturated group.
• the polymerizable Z group is a non-conjugated ethylenically unsaturated group selected from alkenyl, alkynyl and allyl groups, and is preferably not a vinyloxy group, e.g.
• CH 2 CHO- or (meth)acrylate group.
• the -Q-Z moiety may be of the formula:
• the-Q-Z moiety may be of the formula
• the copolymer of Formulas I and II are generally prepared by nucleophilic displacement of commercially available halogenated PIBs, including halogenated poly(isobutylene-co-methylstyrene), halogenated poly(isobutylene-co-isoprene).
• a non-halogenated PIB-based material may be halogenated
• halogen moiety in those materials allows introduction of the pendent ethylenically unsaturated groups.
• the reaction scheme involves a displacement reaction with a "nucleophilic ethylenically unsaturated compound”; an organic compound with at least one nucleophilic functional group and least one ethylenically unsaturated group (hereinafter a "nucleophilic unsaturated compound”).
• the unsaturated group may be an alkenyl, including vinyl, allyl or allyloxy and the nucleophilic functional group may be an amino, carboxyl or hydroxy group.
• carboxyl groups are less nucleophilic than hydroxyl or amines, the nucleophilic substitution may be enhanced by using a phase-transfer catalyst such as tetra-n-butylammonium hydroxide.
• the nucleophilic unsaturated compound is a polyunsaturated compound having a hydroxyl group and one or more unsaturated groups, including terpene alcohols and acids, which are derived from plant materials.
• the nucleophilic unsaturated compound consists of a carboxy group with one or more unsaturated groups such as those carboxy comounds derived from unsaturated fatty acids such as linoleic acid, linolenic acid, and arachidonic acid.
• this disclosure provides an adhesive composition derived from renewable resources.
• the present invention further provides an adhesive article, wherein the substrate or backing is also derived from renewable resources.
• Terpene alcohols and acids are a well-defined class of compounds that are based on five-carbon isoprene units and have at least one hydroxyl, which can be primary, secondary, or tertiary or carboxylic acid group.
• the terpene alcohols and acids are acyclic or mono-, hi- or tricyclic, mono- or po!yo!efinicaUy unsaturated alcohols of vegetable origin containing between 10 and 40 carbon atoms, Terpene alcohols and acids are structurally similar to terpene hydrocarbons except the structure also includes some hydroxyl or carboxyl functionality.
• Terpene alcohols and acids may be found in essential oils and are generally available through commercial sources.
• Examples of unsaturated aliphatic terpene alcohols include geraniol, nerol, citronellol, hydroxycitronellol, linalool, a-terpenol, borneol, isoborneol, terpinen-4-ol, limonen-4-ol, carveol, lavandulol, menthol, 8-p-cymenol, cis-pinanol, trans-pinanol, dihydromyrcenol, myrcenol, dihydrolinalool, isomenthol, neomenthol, isopulegol, trans-p- menthane-3,8-diol, isoborneol, globulol, cedrol, menthol, sobrerol, umbellulol, nerolidol, pinanediol, farnesol, frenchyl alcohol, eugenol, phytol, isophytol
• useful unsaturated nucleophilic compounds include those of the formula: wherein
• R 2 is a multivalent saturated or unsaturated alkylene or arylene, and each R 5 is independently selected from H or C 1 -C4 alkyl, and any two of the R 5 groups may be taken together to form a carbocyclic ring, such as are found in many terpene alcohols, and q is 1 or 2. Preferably q is greater than 1.
• the resulting nucleophilic polyunsaturated compounds allow the addition of multiple crosslinking sites on the copolymer.
• R 2 is a multivalent saturated or unsaturated alkylene or arylene, and each R 5 is independently selected from H or C 1 -C4 alkyl, and any two of the R 5 groups may be taken together to form a carbocyclic ring, such as are found in many terpene alcohols, and q is 1 or 2;
• X 2 is a leaving group such as a halide, and preferably a bromide,
• R 1 is a multivalent alkylene or arylene.
• the isobutylene copolymer having pendent, free-radically polymerizable, ethylenically unsaturated groups is prepared by nucleophilic displacement of a halogenated isobutylene copolymer, with a nucleophilic ethylenically unsaturated compound.
• Compounds of Formula III include terminally mono-, di- or poly- unsaturated ethers of polyols such as 1,3-butylene glycol, 1 ,4-butanediol, 1,6-hexanediol, cyclohexane dimethanol, neopentyl glycol, caprolactone modified neopentylglycol hydroxypivalate, diethylene glycol, dipropylene glycol, bisphenol-A, trimethylolpropane, neopentyl glycol, tetraethylene glycol, tricyclodecanedimethanol, triethylene glycol, tripropylene glycol; glycerol, pentaerythritol, and dipentaerythritol pentaacrylate.
• polyols such as 1,3-butylene glycol, 1 ,4-butanediol, 1,6-hexanediol, cyclohexane dimethanol,
• nucleophilic unsaturated compounds include hydroxyalkenes such as allyl alcohol, methallyl alcohol, allyloxyethyl alcohol, 2-allyloxymethylpropanol (from dimethylolethane), and 2,2-di(allyloxymethyl)butanol (from trimethylolpropane), as well as the corresponding amines, particularly diallylamine.
• the copolymers of isobutylene may include those wherein isobutylene is copolymerized with another monomer, which may be subsequently modified to include the pendent unsaturated group.
• Synthetic rubbers include butyl rubbers which are copolymers of mostly isobutylene with a small amount of isoprene, for example, butyl rubbers available under the tradenames VISTANEX (Exxon Chemical Co.) and JSR BUTYL (Japan Butyl Co., Ltd.).
• the copolymers are substantially homopolymers of isobutylene, for example, polyisobutylene resins, which may be subsequently modified to include the pendent unsaturated group, available under the tradenames OPPANOL (BASF AG) and GLISSOPAL (BASF AG).
• the copolymers also include copolymers of mostly isobutylene with n-butene or butadiene, which may be subsequently modified to include the pendent unsaturated group.
• a mixture of copolymers may be used, i.e., the first polyisobutylene comprises a
• Blends of isobutylene homopolymer and modified poly(isobutylene) are also contemplated.
• the isobutylene copolymer may comprise a random copolymer of isobutylene and modified paramethylstyrene units, wherein said random copolymer contains 1 to 20% by weight of said modified paramethylstyrene units and has a crosslinked structure.
• This random copolymer is, for example, commercially available from Exxon Chemical Co. under the trade name of EXXPRO series, and examples thereof include MDX90-10, MDX89-4.
• a portion of the methyl groups at the para-position of this paramethylstyrene can be brominated to form a site for the subsequent nucleophilic displacement by a compound of Formula III. Accordingly, a crosslinked structure can be formed by the technique described in detail hereinafter.
• copolymer MDX90- 10 1.2% by mol of paramethylstyrene, which is contained in the copolymer in the amount of 7.5% by weight, is brominated.
• MDX89-4 0.75% by mol of
• paramethylstyrene which is contained in the copolymer in the amount of 5% by weight, is brominated.
• bromination of paramethylstyrene and random polymerization between isobutylene and paramethylstyrene, for the purpose of producing a random copolymer can be performed by known techniques.
• Paramethylstyrene monomer units can also impart heat resistance and strength to the copolymer by the cohesive force and hardness of paramethylstyrene itself.
• paramethylstyrene is preferably contained in the copolymer in amounts of greater than zero, preferably about 1 to 20 parts by weight based on the total amount of the copolymer. When the amount of paramethylstyrene is smaller than 1 part by weight, the cohesive force is insufficient and it becomes difficult to obtain enough adhesion to endure practical use.
• tackifiers include phenol modified terpenes, hydrocarbon resins such as polyvinyl cyclohexane and poly(t- butyl styrene), and rosin esters such as glycerol esters of rosin and pentaerythritol esters of rosin.
• tackifiers include phenol-modified terpenes and rosin esters such as glycerol esters of rosin and pentaerythritol esters of rosin that are available under the trade names NurozTM, NutacTM (Newport Industries), PermalynTM, StaybeliteTM, ForalTM (Eastman).
• hydrocarbon resin tackifiers that typically come from C5 and C9 monomers by products of naphtha cracking and are available under the trade names PiccotacTM, EastotacTM, RegalrezTM, RegaliteTM (Eastman), ArkonTM (Arakawa), NorsoleneTM, WintackTM (Cray Valley), Nevtack, LX (Neville Chemical Co.),
• tackified pressure-sensitive adhesives can also appear cloudy, demonstrating a loss in the characteristic transparency found in many conventional pressure-sensitive adhesive compositions.
• the cloudiness is an indication of limited or incomplete compatibility of the tackifier and the polymers.
• the reduced compatibility can lead to a degradation of adhesive properties on aging, as evidenced by a loss of tack or reduced peel adhesion.
• the addition of a tackifier to an adhesive composition can be clear and appear to be compatible.
• the adhesive can become cloudy, indicating some incompatibility between the tackifier and acrylic base polymer.
• the present disclosure provides tackified adhesive compositions that overcome problems noted in the art.
• the tackifier is preferably selected from a material that is essentially free of any ethylenically or acetylenically unsaturated bonds.
• the tackifier includes, but is not limited to, hydrogenated rosin resins,
• the tackifier used is selected from hydrogenated C9 petroleum resins such as but not limited to RegalrezTM tackifiers
• hydrophobic tackifiers may be used in amounts of greater than zero, e.g. 10 to 150 parts, preferably 10 to 100 parts, of said tackifier, relative to 100 parts of said isobutylene co)polymer.
• Plasticizers may also be used in the adhesive formulation to provide wetting action and/or viscosity control. These plasticizers are well known in the art and may include hydrocarbon oils, liquid or soft tackifiers, including liquid hydrocarbon resins, liquid polyterpenes, liquid poly(isobutylenes) such as Glissopal tm , and the like, waxes, and mixtures of oils.
• a plasticizer may be present in the pressure sensitive adhesive of the present invention in an amount of from 0 to about 200 parts by weight per 100 parts by weight of the copolymer.
• the adhesives of the present invention may be coated upon a variety of flexible and inflexible backing materials using conventional coating techniques to produce adhesive-coated materials.
• Flexible substrates are defined herein as any material which is conventionally utilized as a tape backing or may be of any other flexible material.
• plastic films such as polypropylene, polyethylene, polyvinyl chloride, polyester (polyethylene terephthalate), polycarbonate,
• PMMA polymethylmethacrylate
• Foam backings may be used.
• inflexible substrates include, but are not limited to, metal, metallized polymeric film, indium tin oxide coated glass and polyester, PMMA plate, polycarbonate plate, glass, or ceramic sheet material.
• the adhesive-coated sheet materials may take the form of any article conventionally known to be utilized with adhesive compositions such as labels, tapes, signs, covers, marking indices, display components, touch panels, and the like.
• Flexible backing materials having microreplicated surfaces are also contemplated. The above-described compositions are coated on a substrate using conventional coating techniques modified as appropriate to the particular substrate.
• compositions can be applied to a variety of solid substrates by methods such as roller coating, flow coating, dip coating, spin coating, spray coating, knife coating, and die coating. These various methods of coating allow the compositions to be placed on the substrate at variable thicknesses thus allowing a wider range of use of the compositions. Coating thicknesses may vary, but coating thicknesses of 2-500 microns (dry thickness), preferably about 25 to 250 microns, are contemplated.
• the adhesive compositions are applied as a solvent solution or dispersion, the solvent evaporated, and the adhesive composition crosslinked on exposure to actinic radiation, such as UV.
• Crosslinking of such solvent-based compositions may occur before, but preferably occurs after coating and solvent removal.
• Suitable solvents such as alkanes, ethyl acetate, toluene and tetrahydrofuran which are unreactive with the functional groups of the components of the copolymer
• the adhesive is applied from the melt as is solvent-free.
• Hot melt coating a PSA composition eliminates the necessity of solvent processing.
• the composition must not be crosslinked before and during the coating process; however, to achieve a PSA with balanced properties (i.e., peel and shear adhesion), the composition eventually must be crosslinked.
• high energy radiation e.g., E-beam or high intensity ultraviolet radiation.
• a photoactive crosslinking species such as benzophenone is added to the composition.
• the hot melt adhesive compositions require a narrower range of molecular weights for the
• the molecular weight of the unmodified poly(isobutylene) copolymer is from 50,000 to 5,000,000, preferably from 100,000 to 300,000 (M w ).
• the adhesive composition may be combined with a crosslinker and cured by actinic radiation.
• Suitable crosslinkers include, but are not limited to: aldehydes, such as benzaldehyde, acetaldehyde, and their substituted derivatives; ketones such as
• acetophenone, benzophenone and their substituted derivatives quinones such as the benzoquinones, anthraquinone and their substituted derivatives
• thioxanthones such as 2- isopropylthioxanthone and 2-dodecylthioxanthone
• certain chromophore-substituted vinyl halomethyl-sym-triazines such as 2,4-bis-(trichloromethyl)-6-(3',4'- dimethoxyphenyl)-sym-triazine.
• concentration of crosslinkers can be present in the range of 0.05 to 6.0, preferably 0.1 to 2 percent by weight of the polymer, and more preferably 0.5 to 1.5 percent by weight.
• the adhesive composition can be cured using a source of actinic radiation of sufficient energy (i.e., wavelength range) to generate free radicals when incident upon the particular photoactive crosslinking agent selected for use in the composition.
• a source of actinic radiation of sufficient energy (i.e., wavelength range) to generate free radicals when incident upon the particular photoactive crosslinking agent selected for use in the composition.
• the preferable wavelength range for the photoactive crosslinking agents disclosed above is 400 to 250 nm.
• the radiant energy in this preferred range of wavelengths required to crosslink the adhesive film of the invention is 100 to 1500 millijoules/cm 2 and more preferably 200 to 800 millijoules/cm 2 . Details of the photocure process are disclosed in U.S. Pat. No. Nos. 4,181,752 and 4,329,384
• low surface energy substrates are those having a surface energy of less than about 45 dynes per centimeter, more typically less than about 40 dynes per centimeter, and most typically less than about 35 dynes per centimeter. Included among such materials are polypropylene, polyethylene (e.g., high density polyethylene or HDPE), polystyrene and poly(methyl methacrylate) (PMMA). Other substrates may also have properties of low surface energy due to a residue, such as an oil residue or a film such as paint, being on the surface of the substrate.
• a residue such as an oil residue or a film such as paint
• the invention bonds well to low surface energy surfaces
• the invention is not limited to being bonded to low surface energy substrates, as it has been found that the inventive adhesive can also bond well to higher surface energy substrates such as, for example, other plastics, ceramics, glass and metals.
• the substrate is selected depending on the particular application in which it is to be used.
• the adhesive can be applied to sheeting products, (e.g., decorative graphics and reflective products), label stock, and tape backings.
• the adhesive may be applied directly onto a substrate such as an automotive panel, or a glass window so that another substrate or object can be attached to the panel or window.
• the adhesive can also be provided in the form of a pressure-sensitive adhesive transfer tape in which at least one layer of the adhesive is disposed on a release liner for application to a permanent substrate at a later time.
• the adhesive can also be provided as a single-coated or double-coated tape in which the adhesive is disposed on a permanent backing.
• Backings can be made from plastics (e.g., polypropylene, including biaxially oriented polypropylene, vinyl, polyethylene, polyester such as polyethylene terephthalate), nonwovens (e.g., papers, cloths, nonwoven scrims), metal foils, foams (e.g., polyacrylic, polyethylene, polyurethane, neoprene), and the like.
• Foams are commercially available from various suppliers such as 3M Co., Voltek, Sekisui, and others.
• the foam may be formed as a coextruded sheet with the adhesive on one or both sides of the foam, or the adhesive may be laminated to it.
• it may be desirable to treat the surface to improve the adhesion of the adhesive to the foam or to any of the other types of backings.
• Such treatments are typically selected based on the nature of the materials of the adhesive and of the foam or backing and include primers and surface modifications (e.g., corona treatment, surface abrasion).
• Additional tape constructions include those described in U.S. 5,602,221 (Bennett et al), incorporated herein by reference.
• additives such as fillers, antioxidants, stabilizers, and colorants may be blended with the adhesive for beneficial properties.
• the side of the backing surface opposite that where the adhesive is disposed is typically coated with a suitable release material.
• Release materials are known and include materials such as, for example, silicone, polyethylene,
• Double coated tapes are typically carried on a release liner.
• polymer may be a homopolymer or a co-polymer, or a mixture thereof.
• Peel adhesion strength was measured at a 90° angle using an IMASS SP-200 slip/peel tester (available from IMASS, Inc., Accord MA) at a peel rate of 305 mm/minute (12 inches/minute) using the procedure described in ASTM International standard, D3330, Method F.
• Test panels were prepared by wiping the panels with a tissue wetted with the corresponding solvents shown in Table 1 using heavy hand pressure to wipe the panel 8 - 10 times. This procedure was repeated two more times with clean tissues wetted with solvent. The cleaned panel was allowed to dry.
• the adhesive tape was cut into strips measuring 1.27 cm x 20 cm (1/2 in.
• the static shear strength was evaluated as described in the ASTM International standard, D3654, Procedure A at 23°C/50% RH (relative humidity) using a 1000 g load and/or at 70°C using a 500 g load.
• Tape test samples measuring 1.27 cm x 15.24 cm (1/2 in. x 6 in.) were adhered to 1.5 inch by 2 inch stainless steel (SS) panels using the method to clean the panel and adhere the tape described in the peel adhesion test. The tape overlapped the panel by 1.27 cm x 2.5 cm. and the strip was folded over itself on the adhesive side, and then folded again. A hook was hung in the second fold and secured by stapling the tape above the hook.
• the weight was attached to the hook and the panels were hung in a 23°C/50% RH room or a 70°C oven. The time to failure in minutes was recorded. If no failure was observed after 10,000 minutes, the test was stopped and a value of > 10,000 minutes was recorded. The mode of failure described in the peel adhesion test was also noted.
• the percent gel was determined as described in the ASTM International standard, D3616-95.
• a round test specimen measuring 63/64 inch in diameter was die-cut from a tape coated with the polymer and cured. The specimen was placed in a mesh basket measuring 1 1 ⁇ 2 inch x 1 1 ⁇ 2 inch. The basket with the specimen was weighed to the nearest 0.1 mg and placed in a capped jar containing sufficient toluene to cover the sample. After 24 hours the basket (containing the specimen) was removed, drained and placed in an oven at 120°C for 30 minutes. The percent gel was determined by calculating weight % of the remaining, unextracted portion to the original sample. A disc of the uncoated polyester backing material of the same size as the specimen was die-cut and weighed. The formula used for percent gel determination is shown below.
• Percent Gel (wt.%) ((Unextracted sample wt. after extraction - uncoated polyester backing wt.) / (Original sample wt. - uncoated backing wt.)) x 100 Materials used for examples
• Lithium aluminum hydride (Alfa Aesar, Ward Hill, MA)
• the oil was distilled and product collected at a temperature of 79-82 °C and a pressure of 5 mm to provide 14.6 g of 2-allylpent-4-enoic acid ethyl ester as a colorless oil whose structure was confirmed by NMR analyses.
• EXXPRO 3745 co-polymer (6.17 g), diallylamine (0.37 g), TEA (0.31 g), and toluene (55.49 g).
• the contents of the flask were stirred with a magnetic stir bar under nitrogen at room temperature. Once all the components completely dissolved, the flask was heated to 105°C. After 5 hours, the reaction was cooled to room temperature and vacuum filtered with a fritted funnel (5 ⁇ pore size) to remove the HBr-TEA salt which formed during the reaction. The filtrate was poured into acetone to coagulate the modified polymer.
• Polymer 2 was prepared by mixing 14 g of EXXPRO 3745 and 6 g of OPPANOL B15 polyisobutylene in a Brabender mixer 50 °C, with roller blade attachments rotating at 100 rpm. After 8 minutes of mixing, 1.32 g of diallylamine was added drop wise into the mixture and allowed to mix for another 5 minutes. Then 2 g of ESCOREZ-1310 tackifier and 2.2 g GLISSOPAL G1000 plasticizer were added and mixed for 5 minutes. The resulting mixture was removed from the mixer and cooled to room temperature.
• Adhesive compositions were prepared by placing 100 parts of Polymer 1 with 400 parts of toluene, 0.2 pph (parts per hundred parts of polymer) photocrosslinker (2,4-bis- trichloromethyl-6(4-methoxy-phenyl)-S-triazine) and varying amounts of tackifier
• Control compositions having the same amounts and types of tackifiers and plasticizers with unmodified EXXPRO 3745 in toluene were also prepared (CI, C2, C3, C4) and coated into tapes. No cross linker was added. The tapes were conditioned at
• Adhesive compositions for Examples 7 - 8 were prepared as described in Example 3 and coated into tapes, except that different amounts of an unfunctionalized, medium molecular weight polyisobutylene (OPPANOL B15) shown in Table 5 were added with Polymer 1 and the amount of photocrosslinker was varied.
• the amounts of ESCOREZ 1310 tackifier and Glissopal 1000 plasticizer were both maintained at 10 pph.
• the total amount of polyisobutylene in the system remained at 100 parts, but the amount of the modified and unmodified polyisobutylene was varied and shown in Table 4 in parts (parts per 100 parts of polymer).
• Example 9 an adhesive composition was prepared and coated into a tape as described for Example 7 except that Polymer 2 was dissolved in 400 parts of toluene to form a solution of 20% solids solution. Then 15 g of the solution was placed in a glass vial and mixed with 3.5 mg of cross linker (2,4-bis-trichloromethyl-6(4-methoxy-phenyl)- S-triazine) and coated. Test results for Examples 7 - 9 are shown in Table 4. Table 4 - Adhesive Properties with Varied Crosslink Density
• Adhesive tapes were prepared as described in Example 8 except that the amount of UV exposure was varied to change the crosslink density of the adhesive.
• the tapes were tested for shear at room temperature and at 70°C, and 90° peel adhesive properties on various substrates. Test results are shown in Tables 5 and 6, respectively.
• Adhesive compositions and tapes for Examples 13 -15 were prepared as described in Examples 4, 7, and 8, respectively, except that the modified PIB was Polymer 4. Test results for shear at 23°C, 50%RH and peel adhesion are shown in Table 8.
• Adhesive compositions and tapes for Examples 16 - 18 were prepared as described in Examples 13 - 15, respectively except that the modified PIB was Polymer 5. Test results for shear at 23°C, 50%RH and peel adhesion are shown in Table 9.
• Adhesive compositions and tapes for Examples 19 - 21 were prepared as described in Examples 13 - 15, respectively, except that the modified PIB was Polymer 6. Test results for shear at 23°C, 50%RH and peel adhesion are shown in Table 10.
• Adhesive compositions and tapes for Examples 22-24 were prepared as described in Examples 13 - 15, respectively, except that the modified PIB was Polymer 7. Test results for shear at 23°C, 50% RH and peel adhesion are shown in Table 11. Table 1 1 - Tape Adhesive Properties with Polymer 6
• Adhesive compositions and tapes for Examples 25-26 were prepared as described in Table 12 with Polymer 8. Test results for shear at 23°C, 50% RH and peel adhesion are shown in Table 13.
• Adhesive compositions and tapes for Examples 27-28 were prepared as described in Examples 25 - 26, respectively, except that the modified PIB was Polymer 9. Test results for shear at 23°C, 50% RH and peel adhesion are shown in Table 14. Table 14 - Tape Adhesive Properties with Polymer 9
• PIB was Polymer 10. Test results for shear at 23°C, 50% RH and peel adhesion are shown in Table 15.
• Adhesive compositions and tapes for Examples 31-32 were prepared as described in Examples 25 - 26, respectively, except that the modified PIB was Polymer 11. Test results for shear at 23°C, 50% RH and peel adhesion are shown in Table 16.
• the gel content of Polymers 1, and 2- 11 was determined by using only the polymer and a cross linker without tackifier or plasticizer. Each composition was prepared by dissolving 100 parts of the polymer in 400 parts of toluene and adding the cross linker in the amounts shown in pph.
• Crosslinker I was 2,4-bis-trichloromethyl-6(4- methoxy-phenyl)-S-triazine, and Crosslinker II was benzophenone.
• Each composition was coated to the sample thickness indicated and dried in an oven set at 70°C. The compositions were cured with the amounts of UV energy shown in Table 17. The gel content of each cured composition was determined as described in the Test Methods.
• An adhesive composition comprising: a) an isobutylene copolymer having pendent, free-radically polymerizable, ethylenically unsaturated groups, b) a tackifier, and c) a photocrosslinking agent.
• the adhesive composition of embodiment 1 comprising greater than 0% by weight but less than 20% by weight of polymerized monomer units having pendent, free-radically polymerizable, ethylenically unsaturated groups.
• polymerizable, ethylenically unsaturated groups are alkenyl groups. 5.
• the adhesive composition of embodiment 2 wherein the monomer units having pendent, free-radically polymerizable, ethylenically unsaturated groups is of the formula:
• Q is a divalent linking group
• R 7 is H or C3 ⁇ 4 and Z is a pendent, free-radically polymerizable, ethylenically unsaturated group.
• photocrosslinkmg agent is selected from aldehydes; ketones; quinones; thioxanthones and chromophore-substituted vinyl halomethyl-sym-triazines photocrosslinkmg agents.
• a is at least 20, and at least one of b and c are at least one
• Q is a divalent linking groups and Z is a pendent, free-radically polymerizable, ethylenically unsaturated group.
• Q is a polyvalent linking group
• R is H or CH 3 and Z is a pendent, free-radically polymerizable, ethylenically unsaturated group.
• R 1 is a multivalent alkylene or arylene
• R 2 is a multivalent arylene or alkylene, and q is 1 or 2, and R 5 is independently H or a Ci to C4 alkyl
• An adhesive article comprising a crosslinked adhesive composition of embodiment 18 on a backing.
• ethylenically unsaturated compound is of the formula:
• ethylenically unsaturated compound is a terpene alcohol or terpene acid.

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