MXPA97007914A - Acrylic adhesives with better adherence - Google Patents

Abstract

The invention provides an adhesive comprising: (A) the polymerization reaction product of starting materials comprising: (a) 25 to 100 parts by weight of a polymerizable component comprising at least one acrylic or methacrylic ester of an alkyl alcohol not tertiary in which the alkyl group contains 4 to 20 carbon atoms, and (b) 0 to 75 parts by weight of a polymerizable component comprising at least one reinforcing monomer, copolymerizable with component (a), the sum of ( a) and (b) constitutes 100 parts by weight, and (B) 1 to 75 parts by weight, per 100 parts by weight of the sum of the components (a) and (b) of a substance that imparts tackiness, wherein the component (B) may or may not be present in the initial materials: the tackifying substance comprises a water-colored hydrogenated resin produced from hydrocarbon raw material, the substance imparting tackiness has: (i) retained aromaticity in a scientific or in weight of monomers on the basis of the raw material of more than 50 percent, (ii) a softening point of 65 to 120 ° C, (iii) an Mz of less than 1800, and (iv) substantially no weight fractions molecular over 70

Description

ACRYLIC ADHESIVES WITH AI FIELD OF THE INVENTION The invention relates to acrylic adhesives with improved adhesion and acrylic adhesives sensitive to pressure with improved adhesion.

ANGECE THE TES OF THE INVENTION Acrylic adhesives, including heat-melting adhesives, heat-activatable adhesives and pressure-sensitive adhesives, are well known in the art to bind a variety of substances such as metals, painted surfaces, plastics and the like. Acrylic adhesives, and particularly acrylic pressure sensitive adhesives are known for their transparency and excellent aging properties. The preparation of pressure-sensitive acrylic adhesives is described in many sources including, for example, the North American patents Re 24,906 (Ulrich), 4,181,752 (Martens et al.), 4,952,650 (Young et al.), And 4,569,960 (Bla e). Despite the versatility of acrylic adhesives, there are certain substances, such as certain types of automotive paints and REF: 25776 low energy olefinic surfaces, to which typical acrylic adhesives do not adhere well. Efforts have been made to improve the adhesion of acrylic adhesives, that is, to develop a more active adherent, for this type of surfaces; the improvement of the adhesion of the base acrylic polymer is commonly practiced. Various types of resins that improve adhesion include phenol modified terpenes, hydrocarbon resins such as polyvinylcyclohexane and poly (t-butyl styrene), and rosin esters such as rosin glycerol esters and rosin pentaerythritol esters. Due to the high solubility parameter of most pressure-sensitive acrylic adhesives and the presence of specific potential interactions between these adhesives and many resins with improved adhesion, a limited selection of resins that improve adhesion is available to formulators. , and especially hydrogenated hydrocarbon resins, are typically not suitable for use in polar acrylic adhesive formulations due to their non-polar character. Resins with improved rosin-based adhesion and selected phenol-modified terpene-based resins and alpha-pinene-based resins work well in various acrylic pressure-sensitive adhesives. However, some problems are still associated with the use of this limited range of resins with improved adhesion and acrylic adhesives. Pressure-sensitive acrylic adhesive formulations with improved adhesion often change color or turn yellow. The yellow appearance of these pressure-sensitive acrylic adhesives with improved adhesion is the direct result of the yellow hue inherent in many of these resins with improved adhesion. With aging and exposure to light, this color change can become more pronounced, even with resin grades with lighter colors. Acrylic adhesives without tackifying substances typically have excellent aging properties. Pressure-sensitive acrylic adhesives with improved adhesion can also give a hazy appearance, demonstrating a characteristic loss in transparency found in many acrylate pressure-sensitive adhesive compositions. The nebulous condition is an indication of limited or incomplete compatibility of the resin that improves adhesion and acrylic polymers. The reduced compatibility can lead to a degradation of the adhesive properties by aging, as becomes evident by a loss of adhesion or a reduced adhesion to the release. In some cases, the addition of the resin that improves adhesion to an adhesive composition has acrylic monomers, polymers, oligomers and a mixture thereof., it can be transparent and appear compatible. However, after removing the solvent, curing the adhesive or aging, the adhesive becomes cloudy, indicating some incompatibility between the tackifying substance and the acrylic based polymer. In addition to these losses in the transparency and stability of acrylic adhesives with improved adhesion, other deleterious effects can be observed when resins which improve adhesion during acrylic polymerization reactions are present in volume. Based on the structure of the resin that improves adhesion, the undesirable effects of adding a resin that improves adhesion include inhibition or retardation of the polymerization reaction and / or alteration of the final polymer structure if the resin that improves the Adherence acts as a chain transfer or chain termination agent. Such effects adversely affect the performance and stability of polymerized acrylates in the presence of these resins that improve adhesion. The chain termination can also result in undesirably high residual volatile materials.

U.S. Patent Nos. 4,243,500 and 4,311,759 (Glennon) discloses an improved adhesion-sensitive adhesive comprising two monofunctional acrylates, an essentially saturated adhesion improving resin, dissolved in the monomer, a non-crystallizing elastomeric material and a sensitive initiator. to irradiation. U.S. Patent No. 5,028,484 (Martin et al.) Discloses the use of 5 to 50 parts of resin that improves the adhesion of poly (t-butyl) styrene to polymerized acrylates. The acrylates have 4 to 12 carbon atoms in the alkyl group and can be copolymerized with 0 to 15 parts of a polar monomer or 0 to 30 parts of a moderately polar monomer. U.S. Patent No. 4,988,742 (Moon et al.) Discloses the use of a resin that improves the adhesion of hydrogenated rosin ester to improve the adhesion of an acrylic terpolymer, U.S. Patent No. 4,726,982 (Traynor et al.) Discloses an acrylic copolymer crosslinked with improved adhesion of an acrylic acid ester and an N-vinyl lactam. The patent application EP 0-342,808 describes an acrylic polymer with improved adhesion with a hydrogenated rosin ester.

U.S. Patent No. 5,130,375 (Bernard et al.) Describes the use of reactive tackifying substances, based on rosin, to modify the properties of pressure sensitive acrylic adhesives, resulting in adhesives with improved high temperature performance and adhesion to release.

By subjecting to radiation curing, the substance that imparts stickiness reticle or grafts form with the polymeric backbone. The patent application EP 196,844 (Jacob et al.) Describes the use of an adherent emulsion to improve the adhesion of acrylic lattices. The tackifying substances are predominantly C-5 or (C-5) 2 combined with 10 to 60 weight percent of an aromatic monomer. The patent application EP 383,497 (Yeadon et al.) Discloses the use of non-hydrogenated hydrocarbon resin with an Mw below 2000 and an aromatic content of from 35 to 85 percent with respect to improving the adhesion of acrylic polymers comprising at least 40 weight percent butyl acrylate. The compatibility of the resins is judged by the transparency of the fresh, dry coating. U.S. Patent Nos. 5,013,784, 5,095,065 and 5,164,441 and PCT patent applications WO 90/15111 'and WO 91/18070 (all assigned to Exxon) disclose compositions and processes for rendering acrylic copolymeric grids with improved adhesion with high release resistance Improved cohesiveness In these process descriptions, the tackifying substance is dissolved in the monomers and is present during the polymerization reaction. The substances that impart stickiness are defined as hydrogenated resins, whether they are hydrocarbons, rosin or polyterpene. Solubility in the monomers at room temperature is used as a criterion for selecting substances that impart tackiness, but no mention is made of the compatibility of the sticking substance in the finished polymer. Hydrocarbons are defined as resins having an average molecular weight of from about 500 to about 5000 and an aromatic content of at least 10 weight percent. Release and tear tests are performed shortly after drying and no long-term aging tests are described, which may reveal compatibility trends of the tackifying substance. In addition, transparency requirements are not established for dry adhesive, ie, an adhesive adhesive, although opalescent or nebulous, will still be acceptable.

There is a current need for an acrylic adhesive composition, with improved, transparent adhesion having excellent aging and light stability properties. There is an additional need for an adhesive composition with improved adhesion, transparent, stable, consisting of a polar acrylic adhesive and a resin that improves the adhesion of hydrocarbon hydrocarbon which resists the lack of miscibility typical of such mixtures. There is a further need for an acrylic adhesive composition with improved adhesion in which the tackifying resin does not substantially interfere with bulk polymerization, particularly with the radiation polymerization of (meth) acrylate and other free radical polymerizable monomers.

BRIEF DESCRIPTION OF THE INVENTION The invention provides an adhesive comprising: (A) the polymerization reaction product of the starting materials comprising: (a) 25 to 100 parts by weight of a polymerizable component comprising at least one acrylic or methacrylic ester of an alcohol of non-tertiary alkyl in which the alkyl group contains 4 to 20 carbon atoms; Y (b) 0 to 75 parts by weight of a polymerizable component comprising at least one reinforcing monomer, copolymerizable with component (a), the sum of (a) and (b) constitutes 100 parts by weight; and (B) 1 to 75 parts by weight, per 100 parts by weight of the sum of the components (a) and (b) of a substance imparting tack. Component (B) may or may not be present in the initial materials. The tackifying substance comprises a water-colored, hydrogenated resin produced from a hydrocarbon feedstock; the substance imparting tackiness has: (i) a retained aromaticity, in a weight percent of monomers based on the raw material, of more than 50 percent; (ii) a softening point of 65 to 120 ° C; (iii) an Mz of less than 1800; and (iv) fractions that substantially do not have a molecular weight greater than 7000. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description or can be learned by practice of the invention.

The objects and other advantages of the invention are carried out and are obtained by the methods and articles that are particularly indicated in the described description and claims for the same. It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are considered to provide an additional explanation to the invention as claimed.

DESCRIPTION rngT &T.T.ana, DE THE INVENTION The adhesives of the present invention are acrylic polymers with improved adhesion with a resin that improves the adhesion of aromatic, hydrogenated, water-colored hydrocarbon having retained aromaticity greater than 50 percent, preferably greater than 70 percent, and more preferably greater than 80 percent, based on the amount of monomer in the raw material. A preferred range of retained aromaticity is from 70 to 95 percent, more preferably from 80 to 95 percent. Useful tackifying resins have an average molecular weight Z ranging from about 500 to 1800, preferably between about 600 and 1500, and more preferably from about 650 to 1200. In a highly preferred embodiment of the invention, the tackifying resin has an average molecular weight Z between about 700 and 1100. It is further preferred that the average molecular weight Z is less than 1500. More preferably less than 1200, and more preferably less than 1000. The resins that improve Useful adhesion also have a narrow molecular weight distribution with a polydispersity (Mw / Mn) of less than 2.5, preferably less than about 2.1 and more preferably less than 1.9. The molecular weight characterizations are determined by gel termination chromatography using a polystyrene calibration base and then performing conversion to a polyisobutylene calibration base, according to the following equation: (1) log (MwpoliisobutUeno) - 1. 1 x log (Mw poUest? Reno) - 0. 517 The process is described in detail in WO-A-91-07472 (Luvinh), which is incorporated herein by reference. The softening points (ring and sphere softening points determined by ASTM E-28) of these tack-improving resins typically fall within the range of from about 40 ° C to about 120 ° C., and preferably from about 65 ° C to about 100 ° C. The resins, after hydrogenation, are transparent and essentially colorless. Preferably, they are water-colored. A "water-colored" resin is defined as a resin having a fused Gardner color of less than about 2. An especially preferred resin has a fused Gardner color of less than 1. The resin preferably also shows an initial color after hydrogenation of more than 24 Saybolt (10% solution), in toluene. Useful resins that improve adhesion are hydrogenated petroleum hydrocarbon resins that can be produced by catalytic polymerization of mainly aromatic monomers. After polymerization and hydrogenation, these aromatic monomers retain at least 20% of aromatic protons, determined by nuclear magnetic resonance (NMR), and preferably with at least 24% of aromatic protons. The aromaticity is measured by NMR analysis (lH-NMR) by generally accepted procedures. The "retained aromaticity" is the ratio of the NMR aromaticity of the proton of the hydrogenated resin to the polymerized resin prior to hydrogenation. The process is described in detail in WO-A-91-07472 (Luvinh).

Resins that improve adhesion can be prepared by the following procedure: (a) polymerizing a steam of cracked distillates under Friedel-Crafts polymerization conditions, or fractions thereof, having boiling points between about 135 ° C and 220 ° C. ° C, and containing at least 40% by weight of a vinylaromatic monomer content, in the presence of 0 to 40% by weight of the polymerization mixture of a chain transfer agent; and (b) catalytically hydrogenating the result of step (a), so that at least 75% of the aromaticity is retained. The resins that improve adhesion are preferably prepared by catalytic polymerization of petroleum fractions identified as middle fraction distillates or HCD, and 0 to 40% by weight of a chain transfer agent. The resins are typically prepared from vinylaromatic streams comprising the following components: Distilled Typical of Components Typical Interval the fraction ia Styrene 1- 15 8 Derivatives alkyl styrene 15-40 25 Indene 5-20 10 Derivatives alkyl indene 3-15 10 Non-reactive components 15-76 47 Such streams may be derived from steam-traced petroleum distillates, or fractions thereof, having boiling points between about 135 ° C and 220 ° C, insofar as they contain or are modified to contain a sufficient vinylaromatic content. For example, an essentially pure styrene component can be added to commercially available petroleum distillate products that conform to this description, except for styrene. Thus, a vinylaromatic stream constituted in percent by weight, 11.4% styrene, 31.6% styrene alkyl derivatives, 17.1% indene, 5% alkyl indene derivatives and 34.9% non-reactive components, confirms as a suitable resin raw material. The polymerization of the hydrocarbon resin is generally carried out in accordance with the teachings of U.S. Patent No. 4,078,132 (Lepert), incorporated herein by reference. According to this teaching, the branched-chain aliphatic olefins are introduced during the polymerization as chain transfer agents to obtain the softened softening point and a narrower molecular weight distribution. Although this document is directed towards the preparation of unsaturated, substantially non-aromatic, thermoplastic resins, the teachings herein are applicable to feed streams comprising medium-range distillates or feed streams comprised of vinylaromatic monomer or monomers to produce a resin highly aromatic precursor, which, when hydrogenated, can produce the aromatic resin that improves adhesion, described herein. The feed streams may contain at least 40% by weight of total polymerizable monomers, vinylaromatic monomers and preferably at least 50%. The polymerization process of US Pat. No. 4,078,132 is particularly suitable when carried out at polymerization temperatures between -20 ° C and 100 ° C, preferably between 30 ° C and 80 ° C, in the presence of a catalyst. from Friedel-Crafts, such as aluminum chloride (A1C13), and in the presence of chain transfer agents of the branched-chain reactive olefin type, which are preferably isoamylenes, dimetics or mixtures thereof. Most branched-chain reactive olefin compounds will be effective when used in appropriate amounts, as described in U.S. Patent No. 4,078,132. Some compounds, such as isoamylenes, are more reactive and can be advantageously used in smaller amounts to control the softening point and the molecular weight distribution. Useful amounts of the reactive chain transfer agents are typically in the range of 10 to 20% by weight, based on the total weight of the distillate of the average fraction of the vinylaromatic feed stream, and preferably in the range of 10 to 15%. The process conditions described in U.S. Patent No. 4, 514, 554 (Hughes et al.), Incorporated herein by reference, also include a description of the polymerization of the raw materials of the petroleum fraction including isoamylenes. Hydrogenation can generally be carried out according to the teachings in U.S. Patent No. 4,629,766 (Malatesta et al.), Incorporated herein by reference, but other conventional means of hydrogenation can also be used. Typically, temperatures of 200 ° C to 300 ° C are used, at pressures of 10 to 300 kg / cm 2, and hydrogenation or hydrogenation catalysts such as Group VIII metals are used, for example, nickel, palladium, cobalt, ruthenium , platinum and rhodium, group VI metals such as tungsten, chromium and molybdenum, and group VII metals such as manganese and copper. These metals can be used alone or in combination of two or more metals, in metallic form or in activated form, and can be used directly or on a solid support such as alumina or silica-alumina. A preferred catalyst is one which is composed of nickel-sulfur-tungsten in a gamma-alumina support having a fresh catalyst surface area ranging from 120 to 300 meters2 / gram, and containing 2 to 10% by weight of nickel and 10 to 25% by weight of tungsten, as described in U.S. Patent No. 4,629,766. Hydrogenation is typically carried out with a hydrogen pressure of 20 to 300 atmospheres (2.03 x 105 to 3.09 x 107 Newtons per square meter), and preferably between 150 to 250 atmospheres (1.52 x 107 to 2.53 x 107 Newtons per square meter). A further description of the hydrogenation of aromatic resins is described in U.S. Patent No. 3,926,878 and WO-A-91/07472. The hydrogenation is preferably carried out at temperatures, pressures and times with the effective catalysts so that at least 75% aromaticity is retained, preferably 80%, more preferably at least 85% and much more preferable at least 90%. The optimization of the hydrogenation process can be carried out empirically, according to the process described in the above. The adhesives of the invention are prepared from starting materials consisting of from about 25 to 100 parts by weight of at least one alkyl acrylate monomer, and from about 0 to 75 parts by weight of a reinforcing comonomer. The acrylate monomers useful in the practice of the invention are those which have a glass transition temperature of homopolymer of less than about 0 ° C, and preferably less than about -20 ° C. Useful alkyl acrylate monomers are monofunctional esters of (meth) acrylic acid or non-tertiary alkyl alcohols having from 4 to 20 carbon atoms in the alkyl portion, preferably from 4 to 18 carbon atoms, and so more preferably from 4 to 14 carbon atoms. Examples of useful alkyl acrylate monomers include, but are not limited to, n-butyl acrylate, n-hexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, acrylate. of n-decyl, n-dodecyl acrylate and mixtures thereof. Preferably, a monoethylenically unsaturated reinforcing comonomer having a glass transition temperature (Tg) of homopolymer greater than about 15 ° C, preferably greater than 25 ° C, is copolymerized with the acrylate monomers. Examples of useful copolymerizable monomers include, but are not limited to, meth (acrylic) acid, itaconic acid, N-vinylpyrrolidone, N-vinylcaprolactam, substituted (meth) acrylamides such as N, N-dimethylacrylamides, acrylonitrile, acrylate 2- carboxyethyl, maleic anhydride and mixtures thereof. Other suitable polar monomers include monofunctional unsaturated monomers in which the relative amount of the hydrocarbon ester group of the alkyl substituents is high, and the monomers have a higher solubility parameter as compared to the higher substituted alkyl acrylates in the vinyl esters. Examples of such monomers are methylacrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinyl acetate, vinyl propionate and the like. Non-polar monomers such as isobl acrylate can also be used. When a reinforcing comonomer is used, the alkyl acrylate is present in the composition in amounts of about 25 to 99 parts by weight, and the reinforcing comonomer is present in amounts of 1 to 75 parts by weight, wherein the amount total in weight is 100. Useful amounts of each type of monomer vary based on the desired properties of the adhesive. Higher amounts, for example, from about 40 to 75 parts by weight of the monomer having a Tg above 15 ° C will provide heat activatable adhesive compositions, while minor amounts, eg, less than about 40 parts by weight, can provide pressure sensitive adhesive compositions. Generally, it is preferred that the starting materials are constituted with at least two parts by weight of comonomer, per 100 parts by weight of monomer and comonomer, more preferably at least 5 parts by weight of comonomer. For pressure sensitive adhesives, a preferred range for the comonomer is between about 1 and about 30 parts by weight per 100 parts of monomer and comonomer. For pressure sensitive adhesives in which the comonomer is acrylic acid or methacrylic acid, a preferred range is between 1 and 15 parts by weight per 100 parts of monomer and comonomer. As used herein, the term "copolymer" includes terpolymers, tetrapolymers, and the like. Polar comonomers include monomers having strong hydrogen bonding capabilities such as acids, amides, anhydrides, lactams, nitriles and moderately polar comonomers such as lower alkyl acrylates (1 to 3 carbon atoms) and vinylalkyl lower esters (1 to 3 carbon atoms). The hydrocarbon resin (i.e., the tackifying substance) can be used in amounts of about 1 to 75 pph (parts by weight per 100 parts of the alkyl acrylate monomer and any optional comonomer). Typically, the hydrocarbon resin is present in the adhesive in amounts from about 2 to 50 pph. Preferably, the hydrocarbon resin is present in amounts from about 3 to 45 pph, and more preferably from about 5 to about 30 pph. In the practice of the invention, the resin that improves adhesion is particularly useful in combination with acrylic adhesives in which the adhesive is a copolymer of at least one alkyl acrylate monomer and a polar comonomer. In general, the addition of a comonomer having a vitreous transition temperature of higher homopolymer, and in particular, a polar comonomer such as acrylic acid, will result in improved cohesiveness of the adhesive which in turn will exhibit increased tear strength. Commercially available hydrocarbon-improving hydrocarbon-improving resins are often not compatible with polar monomers of acrylic polymers having polar monomers bonded by hydrogen, and such adhesion-improving adhesives usually have a low tear strength and show decreased adhesion. to the substrate as the adhesive ages for a period of time. The adhesives of the present invention are preferably transparent and essentially colorless. In the practice of the invention, acrylic polymers can be polymerized by techniques including, but not limited to, conventional techniques of emulsion polymerization, solvent polymerization, volume polymerization and radiation polymerization, including processes using light. ultraviolet, electron beams and gamma radiation. The starting materials may comprise a polymerization initiator, especially a thermal initiator or a photoinitiator of a type and in an amount effective to polymerize polymerizable components (a) and (b). Solvent polymerization is well known in the art and is described in various sources such as U.S. Patent Nos. 24,906 (Ulrich), and 4,554,324 (Husman et al.). Briefly, the process is carried out by adding the monomers, a suitable solvent such as ethyl acetate and an optional chain transfer agent to a reaction vessel, adding a free radical initiator, purging with nitrogen and keeping the vessel in place. reaction at an elevated temperature, typically in the range of about 40 and 100 ° C until the reaction is completed, typically in about 1 to 20 hours, based on the batch size and temperature. Suitable initiators for free radicals are commercially available such as those available from DuPont Company under the trademark designation VAZO. Specific examples include VazoMR64 (2, 2'-azobis (isobutyronitrile)) and VazoMR52. Suitable initiators also include hydroperoxides such as tert-butyl hydroperoxide and peroxides, such as benzoyl peroxide and cyclohexane peroxide. The hydrocarbon resin can either be added to the monomers before the polymerization or it can be added to the adhesive mixture after the polymerization. Emulsion polymerization is also described in US Patent No. Re 24,906 in which the monomers are added to distilled water with an emulsifying agent and the suitable initiators in a reaction vessel, purged with nitrogen and heated, typically to a temperature in the range of about 25 to 80 ° C, until the reaction is complete. Again, the hydrocarbon resin can be added either to the monomers before the polymerization, or it can be added to the adhesive mixture after the polymerization. The adhesives of the invention can also be prepared by volume polymerization methods in which the adhesive composition comprising the monomers, the adhesion improving resin and the free radical initiator is applied as a coating on a flat substrate such as a film. polymer and is exposed to an energy source in a low oxygen atmosphere, for example, less than 1000 parts per million (ppm) and preferably less than 500 ppm, until the polymerization is substantially complete, ie, the monomers residuals are less than 10%, and preferably less than 5%. Alternatively, a sufficiently oxygen-free atmosphere can be provided by enclosing or enclosing the composition with, for example, a polymeric film. In one embodiment, a film may be superimposed on the top of the coated adhesive composition prior to polymerization. In another embodiment, the adhesive composition is placed in bags, which can optionally be sealed, and then exposed to energy, for example heat or ultraviolet radiation, to form the adhesive. The adhesive can be supplied from the bags for use, or * the bags can be fed to a heat fusion coater and coated onto a substrate to make tapes or other types of substrates coated with adhesive. In the latter case, the bag material must be melt-meltable by heat with the adhesive in the bag, and the bag material must not adversely alter the desired final properties of the adhesive. Preferably, the adhesive composition is substantially free of solvent. As used herein "substantially solvent-free" refers to an adhesive that has been prepared without the use of large amounts of solvent, ie, less than 5% by weight of a coating composition, preferably less than about 2%, and more preferably no additional solvent is added. The preparation of the adhesive includes processes used in the polymerization of the monomers used as the adhesive as well as processes in the coating process for making finished articles, for example tapes manufactured with the adhesive. The term "solvent" refers to both water and conventional organic solvents used in the industry which are volatilized in the process. These organic solvents include, for example, toluene, heptane, ethyl acetate, methyl ethyl ketone, acetone and mixtures thereof. Other polymerization methods, such as the continuous free radical polymerization method, are described in U.S. Patent Nos. 4,619,979 (Kotnour et al.) And 4,843,134 (Kotnour et al.), Both incorporated herein by reference, which are also incorporated by reference. they can be used to prepare the adhesives of the invention. The adhesives of the invention can be formulated to be heat-melting adhesives and / or heat-activated adhesives by any of the polymerization methods mentioned above. The heat activated adhesives are those that are substantially non-stick at room temperature, but they become sticky when heated. In a preferred practice of the invention, the resin that improves the adhesion of the hydrocarbon is dissolved in the acrylate monomers or in an acrylic syrup. As used herein, a syrup refers to a mixture in which adhesion has been improved to a viscosity that can be applied as a coating, that is, preferably between about 300 and 10,000 centipoise or greater, based on coating method used, which includes mixtures in which the monomers are partially polymerized to form the syrup, and monomer mixtures which have been thickened with fillers such as silica and the like. Preferably, the syrups of the invention are formed by partial polymerization of the monomers by free radical initiators, which are known in the art and can be activated by thermal energy or radiation such as ultraviolet light. In some cases, it is preferred to add an additional monomer to the syrup, as well as a photoinitiator and other additional adjuvants. An effective amount of at least one free radical initiator is added to the acrylate monomers or syrup. The mixture is then applied as a coating on a substrate such as a transparent polyester film, which can optionally be coated with a release coating, and exposed to ultraviolet radiation in a nitrogen-rich atmosphere to form a sensitive adhesive. the pressure. Alternatively, oxygen can be excluded by superimposing the coated adhesive with a second coated polyester release film. Preferably, ultraviolet radiation is provided by ultraviolet lamps which have the greater part of their emission spectrum between about 280 and 400 nanometers (nm) with a peak at approximately 350 nm, and a lower intensity at approximately 20 milliWatts / cm2 (mW / cm2). The subsequent exposure of the adhesive to a second energy source can be used to crosslink or further cure the adhesive. Such energy sources include heat, electron beams, gamma radiation and high intensity ultraviolet lamps, such as mercury arc lamps. The adhesive compositions of the invention are particularly suitable for ultraviolet radiation polymerization because the tackifying resins of useful hydrocarbons do not phase separate after they have been incorporated into the composition, as evidenced by the opalescent or the opacity in the adhesive, and do not impart color, such as the yellow color which can inhibit (i.e., completely stop) or retard the polymerization process and result in an undesirably high volatile monomer / oligomer residual content. In an alternative embodiment, the adhesive composition utilizes a thermally activated initiator. The composition can be applied as a coating on the film treated for release, covered with a second film treated for release and the composite material placed in a heat transfer fluid and heated to a temperature sufficient to carry out the polymerization. Useful free radical initiators include thermal and photoactive initiators. Examples of useful thermal free radical initiators include those described above for the polymerization of solvents. In a preferred embodiment, the initiator is a photoinitiator and includes, but is not limited to substituted acetophenones such as 2,2-dimethoxy-2-2-phenylacetophenone, benzoin ethers such as benzoin methylether, substituted benzoin ethers such as anisoin methylether and substituted alpha-ketoles such as 2-methyl-2-hydroxypropiophenone. Copolymer photoinitiators are also useful. The photoinitiators can be used in amounts of about 0.001 part by weight per 100 parts of monomer and optional comonomer (pph) to about 5 pph, based on the type and molecular weight of the photoinitiator. The preferred amounts vary between about 0.1 pph and about 1 pph. Pressure sensitive adhesives can also be crosslinked to provide greater tear resistance. For radiation curing, useful crosslinking agents include multifunctional acrylates such as those described in U.S. Patent No. 4,379,201 (Heilman), which include, but are not limited to, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, diacrylate 1,2-ethylene glycol, pentaerythritol tetracrylate and mixtures thereof, photoactive triazines such as those described in U.S. Patent Nos. 4,329,384 (Vesley et al.), 4,330,590 (Vesley), and 4,391,687 (Vesley), copolymerizable aromatic ketone comonomers such as those described in U.S. Patent No. 4,737,559 (Kellen et al.), organosilanes, benzophenones, isocyanates and bisamides. Crosslinking agents are generally included in amounts from about 0.002 pph to about 5 pph, and preferably from about 0.01 pph to about 0.5 pph. The amount used will depend on the amount of functionality and molecular weight of the crosslinking agent, and the desired properties of the adhesive. Physical crosslinking agents such as copolymerizable comonomers described in U.S. Patent No. 4,554,324 (Husman et al.), Incorporated herein by reference, may be used. Useful amounts of macromonomers range from about 1 pph to 20 pph, and preferably from 2 pph to 10 pph. Other adjuvants may be included in the composition in amounts necessary to carry out the desired properties insofar as they do not alter the desired final properties of the adhesive. Useful adjuvants include dyes, pigments, silica, hydrophobic silica, cellulose, fibers, glass or polymer spheres, polymer particles, electrical or thermally conductive particles.

The pressure-sensitive adhesives can be supplied as transfer belts in which the adhesive is provided in strip form on a release liner, a double-coated tape in which a transport or support layer is interposed between the two adhesive layers, or as a pressure sensitive adhesive tape in which the adhesive is provided on a permanent backing or backing. Release coatings include, for example, paper, polymeric films, woven or non-woven fabrics which have been treated on at least one major surface, and preferably on both major surfaces with a release agent such as silicone, perfluoropolyether, TEFLON "11 and the like Permanent tape supports include, but are not limited to, foamed sheets such as acrylic foams, polyethylene foams, urethane foams, polymeric films and sheets, metallic foils and woven and non-woven fabrics The transport layers for the double coated tapes include those useful for permanent tape supports and may have different adhesives on each side of the tape For example, a pressure sensitive adhesive of the invention is placed on one side of the tape. transport layer, and a second adhesive is placed between the other side of the transport layer. r of the same type or of a different type of pressure sensitive adhesive, for example, acrylic, synthetic rubber, natural rubber or silicone pressure sensitive adhesive, a hot melt or thermosetting adhesive. The tapes of the invention can be prepared by laminating an adhesive transfer tape to the backing or transport, or the adhesive composition can be applied as a coating on the backing of a transport and can be cured in situ. When a foam-like pressure-sensitive adhesive tape is desired, the monomers or the syrup may include microspheres. Useful microspheres can have a size ranging from about 5 to 200 micrometers in diameter, and preferably from about 10 to 80 micrometers. Suitable commercially available microspheres include expandable microspheres sold under the trade name "Expancel" of Kema Nords Plastics and those sold under the trade name "Micropearl" of Matsumoto Yushi Seiyaku. The microspheres are expanded by heating and can be incorporated into the adhesive composition in expanded form, or they can be added in unexpanded form to the adhesive composition and subsequently heated, to provide a foam-like tape. Glass or ceramic microspheres can also be used. Useful amounts of microspheres range from about 2% to about 75% by volume of the pressure sensitive adhesive composition. A foam-like tape can also be provided by foaming the pressure-sensitive adhesive composition, as described in U.S. Patent No. 4,415,615 (Esmay et al.), Incorporated herein by reference. Alternatively, tapes using the pressure sensitive adhesives of the invention can also be formed into multiple layer tapes by methods such as those described in U.S. Patent Nos. 4,894,259 (Kuller), 4,818,610 (Zimmerman et al.), and 4,895,738 (Zimmerman et al.). The adhesives of the invention are useful for adhering well to a wide variety of different surfaces including low energy surfaces such as thermoplastic olefins, thermoplastic urethanes, ethylene-propylene-diene monomer rubbers, water-impermeable substances, body side molds automotive, automotive paint surfaces, other plastic and metal surfaces. The adhesives can also be applied to substrates for making labels, medical adhesive tapes, decorative tapes, surgical cures and the like.

The adhesives of the invention are particularly useful in automotive paints as indicated by 90 ° of adhesion to release of at least 11 N / dm after aging for three days at room temperature. The following non-limiting examples serve to further illustrate the present invention in greater detail.

Test Methods Test 1 of Static Tear Resistance A 1.27 cm by 2.54 cm strip of pressure-sensitive adhesive tape is laminated to an anodized aluminum panel 0.51 mm (20 mils) thick measuring approximately 2.54 cm by 5.08 cm. A second panel of the same size is placed on the tape so that there is an overlap of 2.54 cm and the ends of the panels extend opposite to each other. The sample is then moved down with a steel roller of 6.8 kg so that the total contact area of the sample to the panel is 1.27 cm by 2.54 cm. The substrates used for the second panel are stainless steel (SS) or a painted panel indicating the type of paint as described below in the peel adhesion test. The prepared panel is allowed to stand at room temperature, i.e., at about 21 ° C for at least 1 hour. The panel is then placed in an oven at 70 ° C and placed 2 ° to the vertical to avoid a failure in the release mode, and a weight of 500 grams is hung over the free end of the sample. The time required for the heavy sample to fall from the panel is recorded, in minutes. If a failure does not occur in the next 10,000 minutes, the test is suspended and the results recorded as 10,000+ minutes.

Test 2 Static Tear Resistance This test is carried out in accordance with ASTM D3654M-88. A test sample of 1.27 cm wide and approximately 6 cm long is applied to a stainless steel test panel with a minimum pressure and approximately 2 cm of overlap with the test panel. The free end of the tape is held temporarily by a release surface. The sample is moved down with six steps of a steel roller coated with 2 kg hard rubber and the sample is trimmed to provide an overlay of 127 mm x 12.7 mm with the stainless panel.

The stainless panel is then mounted on a test stand at an angle of approximately 2 ° to the vertical (this is done to prevent the adhesive tape from peeling off the stainless panel) and a 1 kg load is applied to the free end of the tape. The failure time is reported in minutes. After 10,000 minutes the test is suspended. If the failure occurs sooner, the failure mode of the adhesive is recorded.

Adhesion to 90 ° Detachment The sheet of pressure-sensitive adhesive is laminated to a sheet or sheet of 0.127 mm thickness (5 mils) of anodized aluminum. A strip of tape measuring 1.27 cm by 11.4 cm is cut from the sheet and applied to a metal substrate that has been painted with one of the following automotive paint compositions of base coat / clear coat: RK-8010, available from DuPont Co. E-176, available from BASF UCC-1000, available from PPG Industries RK-3939, available from DuPont Co. RK-8004, available from DuPont Co. The strip is then moved down using four total passes using a roller of 6.8 kg hard rubber. Before performing the test, the sample is aged under the following conditions: A - 5 seconds at room temperature B - 20 minutes at room temperature C - 3 days at room temperature D - 5 days at 70 ° C. After aging, the panel is mounted on an Instron "Tensile Tester so that the tape is pulled out at a 90 ° angle at a rate of 30.5 cm per minute and at 1.27 cm per minute.The results are determined in pounds per 13 mm (0.5 inches) and converted to Newtons per decimeter (N / dm).

Adhesion to Detachment at 18 ° C This test is carried out in accordance with ASTM D3330-87. A strip of tape 1.27 cm wide and approximately 20 cm long adheres to one end of the test panel. The other end is held so that the tape does not touch the test panel. The strip is then moved down with a steel roller coated with 2 kg hard rubber and allowed to stand for varying periods of time. The test panels used and the resting times are specified in each example. The free end of the tape is then folded back and the 180 ° peel is measured at a backward release rate of 30 cm min "1 from a polypropylene surface or a back peel speed of 228 cm min "1 from a glass surface. Then the release force is recorded. Unless stated otherwise, all failure modes are adhesives from the test substrate.

HYDROCARBON RESINS The resin that improves the aromatic hydrocarbon adhesion used in these examples is prepared according to the above description, and is defined by the properties shown in Table 2.

Table 2 - Properties of Hydrocarbon Resin Softening point 98 ° C Molecular weight by gel permeation chromatography Mw (average weight) 520 Mn (average number) 330 Mw / Mn (polydispersity) 1.6 Mz (average Z) 900 Aromaticity111,% 27 Vitrea transition temperature (midpoint DSC) 51 ° C Color Saybolt (10% solution in toluene) 28 Color Gardner aged (50% solution in solvent) 5 5 hours at 175 ° C Color Gardner cast < 1 Wax turbidity point'2 '70 ° C Volatility, weight percent (5 hours at 175 ° C) 1.2 (1)% of aromatic protons (approximately 95% on an aromatic monomer base) (2) 20 Escorene EVA UL7750, resin 40, paraffin wax 40 (65 ° C MP) Example 1 A pressure sensitive adhesive composition prepared by mixing 54 parts of isooctyl acrylate (IOA), 36 parts of butyl acrylate (BA), 10 parts of acrylic acid (AA), and 0.04 parts of benzyl dimethyl ketal photoinitiator (SCARCARE ^) is prepared. KB-1 available from Sartomer Co.) in a closed container, and purged with nitrogen. As the purging continues with nitrogen, the composition is irradiated with a black ultraviolet light (GE D15T8 BL from General Electric Co.), which is partially inclined with a black ribbon to provide an intensity of approximately 0.15 milliwatts per square centimeter (mW / cm2), measured in accordance with the standard G unit in the industry, to form a syrup having a coating viscosity estimated to be about 3000 centipoise. To the syrup are added 0.16 additional parts of benzyldimethyl ketal, 0.15 parts of 2,4-bis (trichloromethyl) -6- (4-methoxyphenyl) -s-triazine, 20 parts of hydrocarbon resin (described above), and 0.06 parts of 1,6-hexanediol diacrylate. After mixing, the mixture is applied as a blade-type coating to a thickness of approximately 0.076 millimeters on a transparent polyester film that has been coated with a silicone release coating, and then exposed to black fluorescent lamps having 90% of the emission spectrum between 300 and 400 nm with a maximum of about 350 nm, in an inert chamber with nitrogen (50 ppm of oxygen). This process results in a pressure sensitive adhesive transfer tape. The lamps are used above and below the coated network and the intensity of the light is 1.2 mW / cm2 (G units) for 2.2 minutes and increases to 2.2 mW / cm2 for 4.4 minutes. A foam sheet material is prepared as described in U.S. Patent No. 4,415,615 (Esmay et al.), And is primed with a polyamide resin. The pressure sensitive adhesive transfer tape is then heated laminated to the foam sheet material. The foam sheet material coated with the pressure sensitive adhesive is tested in accordance with the procedures described above for adhesion to 90 ° peel and the results are shown in Table 3. The physical appearance of the sensitive adhesive is also noted. to the pressure as well as the amount of volatile substances (Vol.).

Examples 2 - 4 Example 2 is prepared as in Example 1, except that 10 pph of the hydrocarbon resin is used in the adhesive. Examples 3 and 4 are prepared as examples 1 and 2, respectively, except that triazine is omitted and 0.1 pph of 1,6-hexanediol diacrylate and 0.1 pph of trimethylolpropane triacrylate are added. All other samples were laminated to a foam sheet material, prepared as described in Example 1, and tested.

Comparative Examples C1-C7 Comparative examples C1-C3 were prepared as in Example 1, and C4-C7 was prepared as in Example 3, except that the resin that improves adhesion was omitted, or a commercially available resin was used as follows: Cl - Without resin that improves adhesion C2 - 20 parts of Regalrez ^ dlOS (available from Hercules, Inc.) C3 - 20 parts of Regalrezm3102 (available from Hercules, Inc.) C4 - Without resin that improves adhesion C5 - 20 parts of Foral ^ ßS (available from Hercules, Inc.) C6 - 20 parts from Regalrez ^ dlOd C7 - 20 parts from RegalrezMR3102 Table 3 - Test Data 2 Adhesive to detachment 2 Adhesion to detachment E | er nplo Appearance 'Vol - N / dm 30.48 cm / min - N / dm 1 27 cm / min% by weight A B C D A B C D 1 Transparent 1 6 179 294 396 588 151 203 326 333 2 Transparent 1 1 130 168 214 637 63 91 249 364 Cl Transparent 0.5 88 109 158 609 32 39 105 354 C2 Opaque / white 1 2 77 84 193 581 39 39 70 354 C3 Opaque white 1 81 116 129 571 46 60 77 354 Transparent 1.8 175 186 399 627 151 245 298 371 4 Transparent 1.2 121 175 245 641 67 1 19 200 364 C4 Transparent 0.6 84 112 172 571 35 60 109 326 C5 Transparent / yellow 3.8 210 231 533 574 60 1 12 294 343 C6 Opaque / white 1.4 77 109 98 606 42 49 105 350 C7 Opaque / White 1.2 88 88 168 - 46 60 119 350 ^ ol The substances VO látil is determined gravimetrically before and after heating for 2 hours at 121 ° C and are expressed as weight percent. 2 The paint surface for the detachment adhesion test is RK-8010.

The data in Table 3 show that the pressure sensitive adhesives cured by ultraviolet radiation of the invention are transparent and show improved adhesion to detachment on a paint substrate without increasing the amount of volatile substances.

Example 5 A pressure-sensitive adhesive composition is prepared as in Example 3 (with 20 pph of hydrocarbon-improving resin, described above), except that the monomer composition is 46.25 parts of IOA, 46.25 parts of BA and 7.5 parts of AA. The adhesive is heat laminated to a foam prepared as described in example 1, and tested on various automotive paint substrates. The results are shown in table 4.

Comparative Example C8 A tape of pressure sensitive adhesive is prepared as in Example 5, except that 20 parts of hydrocarbon resin are omitted. The results are shown in table 4.

Table 4 - Tests on Automotive Paints Test Substrate Test Example 5 Example C8 E- 176 Adhesion to detachment 90 ° - N / dm - A 242 84 Adhesion to detachment 90 ° - N dm - B 336 133 Adhesion to detachment 90 ° - N / dm - C 525 216 UCC Adhesion to detachment 90 ° - N / dm - A 221 95 Release adhesion 90 ° - N / dm - B 273 133 Release adhesion 90 ° - N / dm - C 501 221 RK-3939 Release adhesion 90 ° - N / dm - A 371 154 Adhesion to detachment 90 ° - N / dm - B 448, 224 Adhesion to detachment 90 ° - N / dm - C 511 529 E- 1"6 Static tear - minutes at 70 ° C (158 ° F) 10,000+ 10,000+ SS Static tear - minutes at 70 ° C (158 ° F) 10,000+ 10,000+ \ 1n2one Volatile Substances -% 1.19 08 The data in Table 4 show that the pressure sensitive adhesives of the invention show superior adhesion buildup to various paint substrates compared to a composition which does not have the hydrocarbon resin.

Flj mplo 6 An adhesive composition is prepared by mixing 45 parts of isooctyl acrylate (IOA), 10 parts of acrylic acid and 0.04 pph of benzyldimethyl ketal photoinitiator (KB-1 available from Sartomer Co.) in a vessel. The vessel is purged with nitrogen and then continuously charged with nitrogen, the mixture is exposed to black ultraviolet light lamps (GE F-15T8BL, available from General Electric Co.) at an intensity in accordance with industry-standard G units. of 0.15 milliwatts per square centimeter (mW / cm2) to form a syrup having a viscosity estimated to be about 3000 centipoise. The following was then added to the syrup: 45 parts of butyl acrylate, 0.1 pph of 1,6-hexanediol diacrylate, 0.1 pph of triacrylate (OTA-480 obtained from Radcure), 16 pph of hydrocarbon tackifier substance (described before) and an additional 0.16 pph of benzyldimethyl ketal photonitizer, and mixed in a horizontal grinding mill for approximately 20 hours until all of the components are dissolved and a clear solution is formed. Just before coating, 0.4 pph of a solution of SnCl2 (propylene glycol (80/20 by weight) is added and mixed in a horizontal mill for approximately 30 minutes. thickness of approximately 0.06 millimeters and is applied as a coating between two transparent polyester films which are coated with a silicone release coating to form a pressure sensitive adhesive, except that the light intensity profile is as follows: 0.75 mW / cm2 for 2.43 minutes, 1.6 mW / cm2 for 2.43 minutes, 2.8 mW / cm2 for 2.44 minutes A pressure sensitive sheet material is prepared and tested as described in example 1. It is determined that the substances Volatile (Vol.) are less than 2% .The adhesion to release on a RK-8004 paint substrate is determined and the test results are as follows: Adhesion to detachment fy. 30.48 cnVmin-N / dm Adhesion to detachment fy 1.27 cm min-N / dm? B C A B C 231 368 385 91 270 263 Example 7 A solution adhesive of a tackifying substance is prepared as follows: 178.43 grams of ethyl acetate are added to a one-liter divided resin flask fitted with a condenser, an addition funnel, a glass stirring rod with a half-moon polytetrafluoroethylene blade, and a mechanical stirrer. Heating is provided by a jacket connected to a variable voltage source. Also 55 grams of a mixture of acrylate monomer of 104.5 grams of isooctyl acrylate (IOA), 99.0 grams of d-butyl acrylate (BA), 16.5 grams of acrylic acid (AA), 2.12 grams of 4-acryloxybenzophenone are added. ("ABP" - 25% solution in ethyl acetate), and 1.01 grams of VAZOMR64 (2, 2'-azobis (isobutyronitrile), a commercially available initiator from DuPont). This solution is stirred at 50 rpm.

This solution is heated to reflux and the remaining acrylate monomer mixture is added dropwise over a period of 60 minutes to the flask through the addition funnel. Once all of the acrylate monomer mixture has been added, the solution is allowed to reflux for 3 hours while increasing the agitation of the solution at 350 rpm. Once cooled to room temperature, the inherent viscosity of the polymer is measured at room temperature in ethyl acetate, at a concentration of 0.5 g / dl, at room temperature. The inherent viscosity is 0.5 dl / g. An adhesive is then prepared in solution with improved adhesion by adding 20 parts per 100 parts of acrylate (alkyl acrylates and comonomers) of the hydrocarbon resin described in the above, to this solution. The adhesive in solution with improved adhesion is then applied as a coating on a transparent polyvinyl chloride film (Scotchcal "# 3334, commercially available from 3M, Co.) and dried in the oven to provide a dry coating thickness of approximately 40 μm. The dry adhesive coating is reticulated by exposure to high intensity UV light (mercury lamps of medium pressure, without inertia), using a dose of approximately 100 m / cm "2 to prepare a sample of tape.The tape sample is applied to a painted metal test panel (E-176, a automotive basecoat / clearcoat paint, commercially available from BASF) using a metal roller coated with 2kg (3 pass) hard rubber and the peel adhesion test is performed at 180 ° C and the release rate of 30 cm sec "1, as described in the above. The results of these tests can be found in table 5.

Comparative Examples C9 v CIO Comparative example C9 is prepared and tested according to example 7, except that the hydrocarbon resin of example 7 is replaced with a resin that improves adhesion, based on hydrogenated rosin (Foral "85, a hydrogenated wood rosin commercially available from Hercules, Inc.) The CIO comparative example is similarly prepared, coated and tested, but no resin is added to improve the adhesion to the solution. Adhesive composition The results of these tests can be found in table 5.

Table 5 Adhesion to detachment (waiting time and aging conditions, in N / dm) min., 3 days, 7 days, Example Ambient temperature Ambient temperature 70 ° C 7 89.8 99.5 129.8 C9 69.7 76.0 118.4 CÍO 53.1 66.0 98.9 The results clearly indicate that the improved adhesion adhesive composition of Example 7 demonstrates superior properties with respect to aging detachment in this polar acrylate adhesive composition. Additionally, Example 7 has a transparency similar to the comparison example CIO to which the adhesion has not been improved, while Example C9 shows some light yellowing.

Examples 8-1Q and Comparative Example CU Water-dispersible, pressure-sensitive adhesive compositions with improved adhesion are prepared according to the method of U.S. Patent No. 4,569,960 (Blake) from 100 parts of a polymerized solution of n-butyl acrylate copolymer: 75:25 acrylic acid, 85 parts of phosphoric acid ester (Rhodafac ^ PE-SlO, a free acid of a complex organic phosphate ester commercially available from Rhone-Poulenc) and 3.6 parts of alkali metal hydroxide (potassium hydroxide) . Various amounts of the hydrocarbon resin described above and the tackifying substance of partially hydrogenated rosin (Foral "AX, commercially available from Hercules, Inc. - Comparative Example Cll), as specified in Table 6, are added. These adhesive compositions These compositions with improved adhesion are applied using a blade-type coating at a thickness of 50-60 μm on a 8.1 kg / ream Cristex® tissue paper (commercially available from Crystal Paper Co.). Tape samples of approximately 2.5 x 10.2 cm are prepared and tests are carried out for immediate adhesion to the 180 ° detachment, as described above, both for stainless steel ("SS") and for polyester cloth ("PET"), commercially available as Wrap Tel Tm from Standard Textiles) as test substrates, additionally, these samples are subjected to industrial laundry tests. As follows: Tape samples are placed in a solution at 80 ° C of 1 gram of a fabric detergent in 200 ml of deionized water (pH = 10.0) for 30 minutes. The samples subjected to washing are classified from 1 (poor) to 5 (excellent), based on the amount of adhesive residue that is in the sample after washing. A rating of "5" is only provided when no adhesive residue can be found in the washed sample, while a rating of "1" indicates that there is no evidence of adhesive dissolution. An intermediate classification indicates some accumulation of the paper tape or fibers.

Table 6 Substance that imparts tackiness Adhesion to detachment Adhesion to detachment Dispersibility Example (parts by weight) (SS, N / dm) (PET, N / dm) in water 8 12.3 64.1 11.6 5 9 24.6 81.0 15.3 5 36.9 83.2 10.4 5 CU 24.6 * 49.9 10.3 3 * Foral ™ AX These results clearly indicate the excellent efficacy or performance of the water-dispersible improved adhesion-sensitive pressure sensitive adhesives of the present invention. Both adhesion to release and dispersibility to water are improved over the formulation with improved adhesion of rosin. In addition, these results are an additional demonstration of this unique combination of a resin with improved hydrogenated hydrocarbon adhesion which provides superior properties and compatibility in a highly polar acrylate pressure sensitive adhesive composition.

Example 11 and Comparative Examples C12-C19 The following examples illustrate the inert chemical condition of the adhesion improving resins of the present invention compared to other classes of commercially available synthetic hydrocarbon tackifying substances used in the acrylate pressure sensitive adhesive formulations. In all of these examples, an IOA / AA 90/10 monomer mixture is polymerized by volume using the UV polymerization method of Example 1, except that crosslinking agents were not used (ie, without triazine or diacrylate of 1, 6-hexanediol). The comparative example C12 is prepared without any resin that improves the adhesion, while 20 parts of the resins that improve the adhesion specified in table 7 were added to the monomer mixtures of example 11 and comparative examples C13-C19 before the polymerization. A crosslinking agent was not used, so that the examples should be analyzed by gel permeation chromatography (GPC) in tetrahydrofuran against polystyrene standards to determine differences in molecular weight. The samples were also checked for transparency after polymerization. The results are shown below in Table 7. Prior to polymerization, all samples were transparent.

Table 7 Example Substance that imparts Mz of GPC Transparency stickiness used Optics 1 1 Hydrocarbon resin 725,000 transparent, colorless C12 None 1,800,000 transparent C13 Foal ^ dS 180,000 transparent, light yellow C14 Regalrez ^ lOlS1 1,360,000 opalescent C15 Regalrez1R 10942 1,200,000 nebulous C16 Regalrez ^ lO 1,250,000 nebulous C17 Regalrez 61084 1,530,000 nebulous C18 Escorez ^ ßO5 1,700,000 opalescent C19 Escorezw53006 1,825,000 nebulous xThe resin that improves the adhesion of transparent hydrocarbon like glass has a softening point ( ring and ball) of 16-20 ° C, commercially available from Hercules, Inc. 2resin that improves the adhesion of transparent hydrocarbon as the glass has a softening point (ring and ball) of 90-98 ° C, commercially available from Hercules , Inc. 3resin that improves the adhesion of transparent hydrocarbon as the glass has a softening point (ring and ball) of 98-106 ° C, commercially available from Hercules, Inc. resin that improves the adhesion of transparent hydrocarbon as the glass has a softening point (ring and ball) of 104-112 ° C, commercially available from Hercules, Inc. 5The resin that improves the adhesion of hydrogenated cyclodiene having a softening point (ring and ball) of 79-90 ° C, and a Gardner color of < 1 in a 50% toluene solution, commercially available from Exxon Chemicals Co.

Resin improving the adhesion of hydrogenated cyclodiene having a softening point (ring and ball) of 105 ° C, and a Gardner color of < 1 in a 50% toluene solution, commercially available from Exxon Chemicals Co. The results show that other synthetic, tackifying substances (comparative examples C14-C19) have little compatibility in this more polar acrylic adhesive and become non-compliant. miscible after polymerization. The substances that impart stickiness Regalrez "1018 and Regalrez" 1094 are completely hydrogenated; the substances that impart stickiness Regalrez 3102 and Regalrez "6108 are partially hydrogenated.

Examples 12-14 A pressure sensitive adhesive in suspension of isooctyl acrylate: methacrylic acid 96: 4, using 0.5% by weight of ZnO suspension as a stabilizer according to the method of example 5 of U.S. Patent No. 4,952,650 (Young et al.) , incorporated herein by reference. The portions of pressure sensitive adhesive in suspension improves its adhesion using 10, 20 and 30 pph of the hydrocarbon resin to form examples 12, 13 and 14, respectively. All the examples demonstrated acceptable adhesion to the skin immediately and in the face of aging.

Example 15 and Comparative Example C2Q Adhesive compositions of IOA / AA 93.5 / 6.5 with improved adhesion were applied with 10 parts of the hydrocarbon resin (example 15) and Foral ^ Sd (comparative example C20) at a thickness of 100 μm. (4 mils) on a PET support primed at 37. 7 μm (1.5 mils) and cured and cross-linked using 0.15% by weight of a triazine crosslinker (2,4-bis (trichloromethyl) -6- (3,4-dimethoxyphenyl) -s-triazine and UV light from low intensity (510 mJ / cm2 PR units and a flat intensity profile of 3.2 mW / cm2) Once cured, these adhesives are transferred to a 2 mil aluminum foil holder. they are tested for adhesion to 90 ° peel and tear adhesion as specified above for various substrates ("SS" = stainless steel; "PC" polycarbonate; MppM = polypropylene). tear results at room temperature (RT), while a load of 500 grams is used for tearing at 70 ° C. The results of the tests are shown below in table 8.

Table fl Test Used Example 15 (N / dm) Example C20 Initial detachment, SS 72.9 73.1 Detachment RT 3 days, SS 135.9 109.7 Detachment 70 ° C 3 days, SS 146.7 129.6 Initial detachment, PC 79.0 76.6 Detachment RT 3 days, PC 87.1 85.8 Detachment 70 ° C, 3 days PC 47.7 42.7 Initial detachment , PP 51.9 47.9 • RT detachment 3 days, PP 61.1 60.2 Detachment 70 ° C, 3 days PP 54.5 64.1 Tear RT, SS (min.) 10,000+ 1,255 * Tear 70 ° C, SS (min) 3,413 * 23 * * PSA cohesive failure Table 8 indicates that the composition with improved adhesion of the present invention matches at least one substance imparting tackiness based on hydrogenated rosin ester, in terms of improved adhesion to release on different surfaces. A surprising result is the remarkable increase in tear strength when the hydrocarbon resin is present during bulk polymerization. It is considered that this improvement in tearing is a result of a very limited interference of this class of hydrocarbon resins with this type of polymerization.

Examples 16-17 v Comparative Examples 2? -C.77 This set of examples illustrates the preparation of heat-activable acrylic adhesive compositions with improved adhesion in formulations containing isobornyl acrylate (IBA) as a reinforcing comonomer. Two solution polymers are prepared by polymerizing IOA / AA / IBA / ABP 50/10/40 / 0.2 (comparative example C21) and BA / AA / IBA / ABP 50/10/40 / 0.2 (comparative example C22) in compositions of monomer at 30% solids in ethyl acetate, according to the method of U.S. Patent No. Re 24,906 (Ulrich). Polymerization starts with 0.3% by weight (based on the monomers) of VAZOMR64 and the reaction is carried out for 20 hours at 55 ° C under an inert atmosphere. A portion of comparative example C21 is improved in strength by 20 parts percent (based on solids) of the hydrocarbon resin, which results in the improved adherent acrylic adhesive of example 16. Similarly, the example is prepared 17 by improving the adhesiveness of a portion of Comparative Example C22 with 20 parts percent of the hydrocarbon resin. All of the four examples were applied as a 38.1 micrometer primed and oven dried polyester (PET) coating. A dry adhesive thickness of approximately 25.4 micrometers is obtained. All tape samples are transparent and essentially non-sticky. Although ABP (4-acryloxy-benzophenone) is incorporated into the adhesive to allow UV crosslinking, UV curing is not used. Strips of 1.25 cm wide adhesive tape of each of these compositions are prepared and the adhesive tapes are heat-laminated to stainless steel test panels for 180 ° peel adhesion and tear adhesion tests. The samples were heat laminated at 90 and 110 ° C by running a tape / test panel construction through the heated narrowing of a laminator (average residence time under narrowing of 2 to 3 seconds). For the detachment adhesion test, a peel rate of 228 cm min "1 was used while the static tear test involved samples that had an overlay of 1.25 cm x 1.25 cm with the test panel and a load of 1 kg applied to the free end of the tape sample.

At 90 ° C, only examples 16 and 17 with improved adhesion can be applied successfully, as demonstrated by the peel test which tore the support. Comparative examples C21 and C22 without improved adhesion applied at this temperature were tested and provide 180 ° release values of approximately 1.1 N / dm. Comparative examples C21 and C22 do not reach this level of adhesion to detachment (ie, the PET support is torn) until the lamination temperature increases to approximately 110 ° C. Static tear was also measured in the examples with improved adhesion and without improved adhesion. No tear failure is observed for examples 16-17 and comparative examples C21, C22, and the test is suspended after 10,000 minutes. These experiments clearly show that the tackifying substance of hydrocarbon resin can be used successfully in a heat activatable adhesive composition. Heat activatable adhesives, with improved adhesion, maintain the optical transparency and tear resistance typical of acrylic adhesive compositions without improved adhesion, but temperature application can be advantageously reduced without adversely affecting performance upon detachment .

It will be apparent to those familiar with the art that various modifications and variations may be made to the present invention without departing from the spirit or scope of the invention. Therefore, it is considered that the present invention covers the modifications and variations of this invention provided to be within the scope of the appended claims and their equivalents. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, property is claimed as contained in the following:

Claims (10)

iis s.

1. A transparent and essentially colorless adhesive, characterized in that it comprises (A) the polymerization reaction product of the starting materials comprising: (a) 25 to 100 parts by weight of a polymerizable component comprising at least one acrylic or methacrylic ester of a non-tertiary alkyl alcohol in which the alkyl group contains from 4 to 20 carbon atoms; Y (b) from 0 to 75 parts by weight of a polymerizable component comprising at least one reinforcing monomer, copolymerizable with component (a), the sum of (a) and (b) constitutes 100 parts by weight; and (B) from 1 to 75 parts by weight, per 100 parts by weight of the sum of the components (a) and (b) of a substance imparting tackiness; the tackifying substance comprises a hydrogenated resin, produced from (1) an aromatic hydrocarbon feedstock containing at least 50% vinylaromatic monomer and (2) from 0 to 40 weight percent transfer agents. olefin chain, the substance imparting tackiness has: (i) a retained aromaticity, in a weight percent of monomers based on the raw material, of more than 30 percent; (ii) a softening point from 65 to 120 ° C; (iii) an Mz of less than 1800; (iv) fractions that substantially do not have a molecular weight greater than 7000; and (v) a fused Gardner color of less than 2.

2. The adhesive according to claim 1, characterized in that the substance imparting tackiness is the substance imparting tackiness described in table 2 - hydrocarbon resin properties.

3. The adhesive according to claim 1, characterized in that the starting materials are substantially free of solvent.

4. The adhesive according to claim 1, characterized in that the initial materials additionally comprise a polymerization initiator.

5. The adhesive according to claim 1, characterized in that the initial materials additionally comprise a thermal initiator or a photoinitiator of a type and in an amount effective to polymerize the polymerizable components (a) and (b).

6. The adhesive according to claim 1, characterized in that the initial materials additionally comprise a crosslinking agent.

7. The adhesive according to claim 1, characterized in that the adhesive is selected from a pressure sensitive adhesive, or a heat activatable adhesive.

8. A sheet material characterized in that it comprises a tape backing or backing or a release liner and an adhesive layer according to claim 1.

9. The adhesive according to claim 1, characterized in that the product of the polymerization reaction is produced by exposing the initial materials to radiation selected from ultraviolet light, electron beam radiation and gamma radiation.

10. The adhesive according to claim 1, characterized in that the component (B) is present in the initial materials during the polymerization.