MXPA97008761A - Article adhesive protec - Google Patents

Abstract

The present invention relates to an adhesive article, characterized in that it comprises: a) a reinforcement or backing having opposite upper and lower surfaces, and b) a pressure sensitive adhesive on the lower surface of the reinforcement, the pressure sensitive adhesive comprises 1) a substantially uncrosslinked poly-alpha-olefin polymer, having an inherent viscosity of about 1.0 to 5.0 dl / g and selected from the group consisting of polyhexene, polyokene, a copolymer of hexene and octene, a copolymer of hexene and propylene, a copolymer of octene and propylene and mixtures thereof, and 2) an effective amount of a flow restriction agent in fr

Description

PROTECTIVE ADHESIVE ARTICLE BACKGROUND OF THE INVENTION Field of the Invention This invention relates generally to adhesive articles and, more specifically, to adhesive articles that are useful for protecting motor vehicles during manufacture, transportation and storage.

Description of Related Art Motor vehicles are painted at the beginning in the manufacturing process. Once painted, the body of the vehicle moves along an automated assembly line so that other parts can be added. During this process the vehicle can be accidentally hit, nicked, dented, etc., by the workers of the assembly line, by the nearby equipment, tools, etc. Depending on the severity of the damage, it may be necessary to repaint the part of the vehicle, which is an expensive and time-consuming process. Once REF: 25991 manufactured, the vehicles are shipped by rail, truck or boat to the distribution centers, and eventually to the merchants who will sell the vehicles. While in transit, vehicles can become damaged or discolored due to gravel flying on the road, soot, metal particles, exhaust gases, strong sunlight, leaking fluids (for example, from adjacent vehicles or vehicles). carrier), acid rain, bird droppings, numerous chemical products, etc. Severe damage may require vehicles to be repainted. Vehicles can be placed in batches of open-pit dealers for several weeks or more before they are sold. During this time these can be damaged by many of the hazards that arise during shipment, as well as by the incidental contact of sales agents and potential buyers. This could result in part of the vehicle having to be repainted. One way to safeguard automotive vehicles during manufacture, transportation and storage is to use a protective adhesive article such as a protective adhesive sheet or adhesive tape (for example, a liner or reinforcement with an adhesive on it). The adhesive articles useful for the construction of automotive vehicles must have certain attributes. For example, they should not leave a printed pattern on the painted surface of the motor vehicle. Variations in raw materials and in the manufacturing process can cause paints used on some vehicles to heal more slowly than paints used on other vehicles. Partially cured paints can be "softer" than fully cured paints. Also, some manufacturers prefer to use "softer" paints. In addition, when vehicles are being shipped, temperatures can be as high as approximately 80 ° C, which can cause some paints to soften. Consequently, the adhesive used in the protective film should be softer than the paint it touches, since an adhesive with less ability to flow could leave an undesirable printed pattern on the painted surface. The adhesive must provide good adhesion to the painted vehicle, so that the protective article does not come off during use. However, it should not be difficult to remove the item when it is no longer necessary. The protective article must also be removed cleanly without leaving traces of adhesive residue on the painted vehicle. In addition, it is desirable that the protective article be recyclable. The growing interest in the environment has created a demand for waste and packaging that can be recycled. Several methods have been developed to protect automotive vehicles during manufacturing, transportation and storage. For example, water soluble or dispersible compositions have been sprayed as temporary coatings which can then be removed with water or alkali.

See, for example, US Patent No. 4,525,501 (Norman et al.), North American Patent No. 3,642,567 (Rogers, Jr.) and North American Patent No. ,006,578 (Masuda et al.). Another method involves spraying a composition on the surface to be protected, drying or curing the composition, and subsequently removing the resulting film by peeling or peeling. For examples, see British Patent Publications Nos. 2,191,717 and 2,253,401 (each for Gramos Chemical). As suggested above, another protection method uses a tape or sheet that includes a pressure sensitive adhesive (PSA) on a backing or backing. The tape or sheet is removed from the motor vehicle when it is no longer necessary. U.S. Patent No. 5,286,781 (Gotoh et al.) Discloses a tape or sheet having a PSA containing a block copolymer, a thickener resin and a polyolefin. European Patent Publication No. 519,278 (Matsui et al.) Discloses a protective sheet utilizing a rubber-based PSA having a dynamic modulus of 2 x 105 to 7 x 106 dynes / cm2 at 60 ° C. Japanese Patent Application Kokai No. Hei 6 [1994] -128538 (Matsui et al.) Discloses a very similar protective sheet which is supplemented by the addition of an antistatic agent. Japanese Patent Application Kokai No. Hei 6 [1994] -128540 (Tsuchibashi et al.) Discloses a protective film having an adhesive layer containing a polyisobutylene or butyl rubber and a primer for bonding the adhesive to a colored backing film olefin type. Japanese Patent Application Kokai No. Hei 5 [1993] -98223 (Kawabata et al) discusses a surface protection film having an adhesive layer consisting of a block copolymer, a thickener resin, and an ethylene-a copolymer -olefin and / or a propylene-α-olefin copolymer on one side of the polyolefin-type base film.

However, there is still a need for improved, protective adhesive articles that do not print the painted surface of a motor vehicle, have good adhesion, can be cleaned and easily removed when they are no longer needed, and can be recycled.

BRIEF DESCRIPTION OF THE INVENTION In general, in one embodiment, the invention relates to an adhesive article comprising a reinforcement having larger upper and lower opposed surfaces, and a pressure sensitive adhesive on the lower surface of the reinforcement. The pressure sensitive adhesive comprises: a) a substantially uncrosslinked poly-α-olefin polymer, selected from the group consisting of polyhexene, polyokene, a copolymer of hexene and octene, a copolymer of hexene and propylene, an octene copolymer and propylene, and mixtures thereof; and b) an effective amount of a reagent that restricts cold flow. In another embodiment, the adhesive articles of the invention are provided in the form of a roll with a low load of adhesion on the upper surface of the reinforcement.

Very advantageously, the adhesive articles of the invention show a variety of properties that make them especially useful as protective adhesive covers, such as for the protection of a motor vehicle painted from damage during manufacture, transportation and storage. For example, the adhesive articles of the invention do not print the painted metal surfaces. In addition, the protective adhesive articles of the invention show good initial adhesion to painted metal surfaces, so that the protective articles will not be released during use. Furthermore, the protective adhesive articles can be easily and neatly removed from the same surface, without tearing into pieces and without leaving an adhesive residue on the surface. Once removed, the protective adhesive articles of the invention can be recycled, whereby it is understood that these can subsequently be processed in molten form (eg crushed and extruded) and the resulting melt or extrudate can be reused, for example in the manufacture of new protective adhesive articles, as well as in the manufacture of plastic bags and other articles that use raw materials The poly-α-olefin polymer preferably has an inherent viscosity of about 1.0 to 5.0 deciliter / gram, although the range of about 1.5 to 2.6 dl / g is more preferred if the polymer of poly-α-olefin is polyhexene, and the range of about 1.2 to 3.2 dl / g is more preferred if the poly-α-olefin polymer is polyokene. It is also preferred that the poly-α-olefin polymer has a polydispersity index of less than or equal to about 10. The cold flow restriction agent typically has a smoothing point of at least about 80 ° C, and can be a material such as polyethylene, polypropylene, ethylene vinyl acetate, blends of a polyolefin and a thermoplastic elastomer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, and styrene-ethylene / block copolymer butylene-styrene. Preferably, the cold flow restriction agent comprises about 5 to 30 parts by weight per 100 parts by weight of the poly-α-olefin polymer, more preferably about 15 to 20 parts by weight, and still more preferably about 20 parts. in weigh.

The reinforcement is preferably a non-elastic, conformable material, so that it can be stretched to follow the complex contours and multiple planes found in automotive vehicles and, once stretched, retains the three-dimensional state it assumes. Useful reinforcing materials include impact modified polypropylene, polypropylene homopolymer blended with low density polyethylene, and polyethylene-polyokene copolymer blended with low density polyethylene.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES In one embodiment, the adhesive articles of the present invention comprise, and more preferably, consist essentially of a pressure sensitive adhesive placed on the undersurface of a reinforcement having opposed upper and lower surfaces. The adhesive article can be provided as a tape or a sheet, a tape being considered as an adhesive article having a length that is substantially greater than its width, while a sheet has dimensions of length and width that are almost the same. The adhesive articles of the invention are particularly useful as adhesive covers for protecting automotive vehicles during manufacture, transportation and storage. The pressure sensitive adhesive used in the articles of the invention comprises and, more preferably, consists essentially of a) a substantially uncrosslinked poly-α-olefin polymer, selected from the group consisting of polyhexene, polyokene, a hexene copolymer and octene, a copolymer of hexene and propylene, a copolymer of octene and propylene, and mixtures thereof, and b) an effective amount of a cold-flow restriction agent. Preferably, the substantially uncrosslinked poly-α-olefin polymer has a polydispersity index of less than or equal to about 10. The polydispersity index is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn). ) of the polymer, and defines the molecular weight distribution. A narrower molecular weight distribution (eg, a small polydispersity index) produces improved properties. When the polydispersity index is greater than about 10, the amounts of the low and high molecular weight fractions are increased. The low molecular weight fraction can act as a plasticizer, softening the adhesive, reducing its modulus, making it more sticky, and increasing the chance that the adhesive residue will remain after removal of the article. On the other hand, the high molecular weight fraction tends to increase the melt viscosity of the adhesive, and can make processing more difficult. The Mw and the Mn of the poly-α-olefin polymer can be measured by gel permeation chromatography. The substantially non-crosslinked poly-α-olefin polymer has an average inherent viscosity (IV) which is selected to be low enough to facilitate the melt processing of the adhesive, whereby the more easily recycled adhesive articles are made. However, the IV should not be so low that the poly-α-olefin polymer can flow or drain over time at room temperature, resulting in adhesion to painted metal surfaces (such as is found in automotive vehicles). ) being highly coated or the adhesive residue that remains on the painted metal surface after removal of the article. Within these guidelines, the IV of the poly-α-olefin polymer should be in the range of about 1.0 to 5.0 dl / g. However, a more restricted range is desired if the poly-α-olefin polymer is to be processable by hot melt. In this case, the IV must be greater than approximately 1.5 dl / g and less than approximately 3.2 dl / g for the polyoxethane and, for the polyhexene, greater than approximately 1.5 dl / g, and less than about 2.6 dl / g. More preferably, the IV of the poly-α-olefin polymer is about 2.1 dl / g. IV can be measured by ASTM D 2857-93. "Standard Practice for Viscosity in Diluted Polymer Solution". The poly-α-olefin polymer is substantially non-crosslinked, whereby it is understood that while the poly-α-olefin polymer is preferably non-crosslinked, a small amount of crosslinking is permissible so long as the initial adhesion of the article to painted metal surfaces will not become unacceptably high and the item will remain recyclable. The poly-α-olefin polymer thus has a gel content which is preferably less than 2% by weight, more preferably less than 1% by weight. The poly-α-olefin polymer can be prepared by polymerizing the α-olefin monomers in the presence of Ziegler-Natta catalysts over a wide range of temperatures (eg 0 ° to 140 ° C, preferably 30 ° to 90 ° C). ° C). The polymerization can be carried out in bulk or in inert solvents. Suitable examples of inert solvents include aliphatic, aromatic and cycloaliphatic hydrocarbons (for example, pentane, hexane, heptane, benzene, toluene, cyclopentane and cyclohexane). The amount of catalyst is preferably in the range of 0.1 g to 5 g per kg of monomer, more preferably 0.2 g to 3 g per kg of monomer, still more preferably 0.5 to 2 g per kg of monomer. Ziegler-Natta catalysts are well known in the art and are described, for example, in Odian, G., Principies of Polymerization, Chap. 8.4 (Second Edition, J. Wiley & amp;; Sons, NY, 1981) and Boor, J., Ziegler-Natta Catalysts and Polymerizations, Chap. 19 (Academic Press, NY, 1979). For an additional discussion of olefin polymers and methods of preparation, see Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd Edition, Vol. 16, pages 470-484. The pressure sensitive adhesive used in the invention also includes a cold flow restricting agent, which is a solid material that reduces the flow of the adhesive under normal use temperatures, such that the initial adhesion of the article to the surfaces painted metal is not too high, and such that the adhesive residue does not remain on the surface after the article has been removed. Temperatures of normal use can be as high as about 80 ° C when the adhesive article is used to protect automotive vehicles during manufacture, transport and storage. Accordingly, the cold flow restriction agent preferably has a softening point of at least about 80 ° C. Examples of useful cold flow restriction agents include polyolefins such as polyethylene and polypropylene, copolymers of polyolefins such as ethylene vinyl acetate, blends of polyolefins with other polymers such as a blend of polypropylene and thermoplastic elastomer, certain thickener resins , butyl rubber, and block copolymers (which may be hydrogenated or not) such as block copolymers of styrene-butadiene-styrene, styrene-isoprene-styrene, and styrene-ethylene / butylene-styrene. Polypropylene is preferred. The cold flow restriction agent is used in an effective amount. As the amount of the cold flow restriction agent increases, the initial adhesion may be too low and the adhesive can no longer demonstrate the pressure sensitive properties (eg, aggressive tackiness after the application of light pressure alone with the finger) As the amount of the cold flow restriction agent decreases, the adhesive may be too sticky, it may flow cold, or a protective article prepared from the adhesive may leave a residue around the wrinkled and bulged areas in the protective article. In this way the cold flow restriction agent must be used in an amount sufficient to produce a pressure sensitive adhesive that does not have high coating or low adhesion to painted metal surfaces, and which can be neatly removed from the surface . Within these parameters, the cold flow restriction agent is typically used in an amount of about 5 to 30 parts by weight per 100 parts by weight of the poly-α-olefin polymer, more preferably from about 15 to 20 parts by weight. weight, and still more preferably about 20 parts by weight. The pressure sensitive adhesive may optionally contain other ingredients such as antioxidants, ultraviolet light absorbers, antistatic agents, fillers, thickeners, dyes, pigments, and fire retardants. The optional ingredients may be present in any amount, such that the operation of the adhesive articles of the invention (e.g., printing, adhesion, clean removal, and recyclability) is not adversely affected. The thickness of the adhesive layer in the articles of the invention is from about 5 to 50 μm, more preferably from about 5 to 25 μm, and more preferably from about 5 to 18 μm per economy. When the thickness of the adhesive layer is greater than about 50 μm, the amount of cold flow is increased, and the amount of residue remaining after removal of the article is also increased. When the thickness of the adhesive layer is less than about 5 μm, the adhesive may not be able to sufficiently prevent the printing of the painted surface. The adhesive articles of the invention include a reinforcement. Preferably, the reinforcements used in the adhesive articles of the invention are sufficiently conformable and non-elastic, so that they can easily follow the complex contours, of multiple planes, typically found in automotive vehicles. When stretched during the application to conform to a particular three-dimensional geometry, the articles must retain the three-dimensional shape that has been imparted to them. The reinforcements must be flexible and have a resistance to breakage that allows the adhesive articles to flex around the sharp corners and edges, typically found in automotive vehicles, without breaking or tearing. The adhesive items must be capable of being removed from the motor vehicle without tearing in several pieces. Such properties are improved by the use of reinforcements which have good resistance to breakage in the machine direction and, preferably, good resistance to breakage in the machine direction and in the transverse direction. The reinforcements useful in the invention should also have a tensile strength of about 210.92 to 421.84 kg / cm2 (3000 to 6000 psi) and a 1% drying modulus of about 3866.88 to 5273.02 kg / cm2 (55000 to 75000 psi) . Suitable materials for the reinforcement include impact modified polypropylene, such as ethylene / propylene rubber modified polypropylene (E-P) and thermoplastic elastomer modified polypropylene (eg, styrene-butadiene-styrene block copolymer). Examples of commercially available impact modified polypropylene include EP polypropylene modified from Shell Polypropylene Company, Houston, Texas, Himont Company, Houston, Texas, Exxon Chemical Company, Houston, Texas, and Dow Chemical Company, Midland, MI. . The reinforcement may contain additional ingredients (such as those described above as the pressure sensitive adhesive) to add stiffness, to impart resistance to environmental conditions or the ability to reflect heat, and the like. The reinforcement may be oriented, for example uniaxially oriented or biaxially oriented by tubular expansion. The orientation in the machine direction up to 1.2x can improve the impact resistance of the adhesive articles of the invention. If the orientation exceeds 1.2x, the resistance to breakage of the adhesive article may decrease. The thickness of the reinforcement may vary with the intended end use for the article. For example, if the article is used with an anti-mutilation tape (for example, to provide protection from light scratches), the thickness of the reinforcement is preferably about 75 to 150 μm. If the article is used to provide protection on horizontal surfaces (for example, protection of fluids, dirt and light gravel pieces), the thickness of the reinforcement is preferably about 35 to 65 μm. The adhesive articles of the invention may be provided with additional layers. For example, adhesive articles may include a printing layer on the reinforcement, which is especially useful when the adhesive article is used as a label or to provide advertising. The adhesive article may include a release layer such as a low adhesion filler on the backing to facilitate the provision of the roll shaped adhesive article (such as a roll of tape) for ease of storage and assortment. For economy, the thickness of the low adhesion filler may be about 2.5 μm or less. Adhesive articles may include a release liner (e.g., a substrate coated with a release agent such as silicone coated paper) to provide the ability to die-cut adhesive articles in specific forms such as to protect around the handles of the doors.

The adhesive articles of the invention can be prepared by a variety of techniques. For example, the adhesive can be extruded onto a preformed reinforcement or the extruded adhesive, and the preformed adhesive can be held together. In the case of heat-sensitive reinforcements, the reinforcement should be slightly displaced from the extruder to allow the extruded adhesive to cool before coming into contact with the reinforcement. Alternatively, the adhesive articles can be prepared by laminating a preformed film of the pressure sensitive adhesive to a preformed reinforcement using heat and pressure, as necessary to ensure a good bond between the adhesive and the backing. Another useful manufacturing technique involves coating the pressure sensitive adhesive with water or an organic solvent over a preformed reinforcement, and then evaporating the water or the solvent by air drying or a low temperature oven. Alternatively, the pressure sensitive adhesive can be coated with the aid of water or an organic solvent on a release liner, dried and laminated to a preformed reinforcement. However, the most preferred method is the coextrusion of the different layers of the adhesive article such as the coextrusion of the pressure sensitive adhesive, the coating or reinforcement and a low adhesion load either through a feed block die or a multiple pipe die. The combinations of these different manufacturing techniques can also be used, such as the coextrusion of the reinforcement and the low adhesion filler, and then rolling or solvent-coating the pressure sensitive adhesive. Very advantageously, the adhesive articles of the invention show a variety of properties that make them especially useful as protective adhesive covers, such as for the protection of a motor vehicle painted from damage during manufacture, transportation and storage. The adhesive articles of the invention do not print painted metal surfaces such as the finish of a painted automotive vehicle. Adhesive articles are useful with a variety of different paints, often used to finish automotive vehicles, such as polyurethanes, melamine-acrylics, and acid catalyzed epoxides. In addition, the protective adhesive articles of the invention show good initial adhesion to the printed metal surfaces, so that the protective articles will not be released during use. Furthermore, protective adhesive articles can be easily and neatly removed from the same surface without tearing into pieces and leaving no adhesive residue on the surface. Once removed, the protective adhesive articles of the invention can be recycled, whereby it is understood that these can subsequently be processed in molten form (eg, crushed and extruded through a film-forming die, such as that which is described in conjunction with example 6 below, for recycling). The resulting melt or extrudate is sufficiently free of gels (typically less than 15% gel content, either from the adhesive or reinforcement) to allow the melt or extrudate to be reused, for example in the manufacture of new protective adhesive articles as well as in the manufacture of plastic bags and other items that use non-virgin raw materials. In use, the protective adhesive articles of the invention are often provided in the form of giant rolls, with a release liner to protect the pressure sensitive adhesive, or with a low adhesion load on the reinforcement. The protective adhesive article is unwound and, for example, is stretched firmly over those portions of the motor vehicle that are to be protected of the damage. The pressure sensitive adhesive provides good adhesion to the painted metal surface of the automotive vehicle and without printing it. The shaping capacity and the non-resilience of the reinforcement make it possible for the protective adhesive article to closely follow the complex and multi-plane contours of the automotive vehicle and retain the three-dimensional shape it assumes after the application. When the protection provided by the adhesive article is no longer necessary or desired, this can be clean and easily removed without tearing pieces and without leaving an adhesive residue on the motor vehicle. The various advantages of the adhesive articles of the invention are further illustrated by the following non-limiting examples, in which all parts are given as parts by weight, unless stated otherwise. Various abbreviations are used in the examples. The abbreviations are defined according to the following scheme.

Example 1 A protective article according to the invention was prepared by extruding a precomposed pressure sensitive adhesive onto a preformed white pigmented polypropylene reinforcement (Exxon 403). The pressure sensitive adhesive was prepared by mixing 200 parts of a polyhexene polymer, IV equal to 2.1, which has a solids content greater than 99%, and 0.25% Irganox 1010 (based on the amount of solids) of polyhexene) in a PL200 Plasticorder mixer (manufactured by CW Brabender Company) maintained at 190 ° C. 35.3 parts of Escorene PP-3505G were added to the molten polyhexene. The mixture was mixed for 20 minutes at 190 ° C, then cooled to below 100 ° C, and removed from the mixer. The precomposed adhesive was extruded to a thickness of 17.5 μm ± 3 μm on an Exxon 403 preformed reinforcement using a 1.9 cm Haake extruder, which was maintained approximately 2 cm from the reinforcement. The width of the die was 12.7 cm and the temperatures of the extruder zone were maintained as follows: Zone 1 = not heated (but registered at 38 ° C due to heat transfer), Zone 2 = 190 ° C, Zone 3 = 190 ° C, die = 190 ° C. A release liner (unbleached 18.14 kg (40 lbs.) Calendered paper coated with a silicone release agent on a surface) was laminated to the reinforcement at the time of extrusion to facilitate the provision of the roll-shaped guard article.

Example 2 Example 2 was prepared according to the procedure described in Example 1, except that the polyhexene had an IV of about 2.4 to 2.6 dl / g.

Example 3 Example 3 was prepared according to the procedure described in Example 1, except that the polyhexene had an IV of 1.7 dl / g.

Example 4 Example 4 was prepared according to the procedure described in Example 1, except that the adhesive included 22.2 parts of Escorene PP-3505G.

Example 5 Example 5 was prepared according to the procedure described in Example 1, except that the adhesive included 50 parts of Escorene PP-3505G.

Example 6 Example 6 was prepared by coextruding a low adhesion filler, a reinforcement and a pressure sensitive adhesive, using a multiple pipe die that diffused each of the streams in an independent pipeline through the full width of the die . In the final 4 cm of the die, the currents came together and the flow of each stream was stable. The temperature and flow rates were adjusted such that the thickness of each layer across the width of the die was uniform. More specifically, the polyhexene of Example 1 was precomposed with Escorene PP-3505G polypropylene in a continuous process using a 3 cm twin screw, three zone extruder where the temperature was maintained at 190 ° C throughout. The weight ratio of polyhexene to polypropylene was 85% / 15%. The precomposed adhesive was fed into the multiple pipe die with a 5 cm Bonnot feed system. The hose from the Bonnot feed system to the multiple pipe die was heated to 180 ° C. The reinforcement formulation was 75 parts of SRD7-462, 25 parts of Ampacet LR85637 and 5 parts of Ampacet 10478. The spheres of these materials were mixed together and fed through a 4.4 cm Prodex extruder with a polypropylene screw. The temperatures in the extruder were Zone 1 = 180 ° C, Zone 2 = 190 ° C, Zone 3 = 203 ° C, and Zone 4 = 221 ° C. The hot extrudate was fed to the multiple pipe die.

The low adhesion reinforcement comprised Aspun PE6806 with an n-methyl-perfluorooctansulfonamido-ethyl acrylate in the presence of 50/50% by weight of homogeneous mixture of Lupersol 101 and Lupersol 130. All three reagents were added to the first zone of an extruder of twin screws, 1600 mm long, and 40 mm in diameter, Berstorff (Berstorff Corp., Charlotte, NC) fitted with partially interengaged front screws, rotating at 150 revolutions per minute. Fully engaged or intermeshed kneading blocks were located in zones four, six, seven and nine. The complete flow rate of the reagents was 605 g / minute, with Aspun PE6806 constituting 99%, n-methyl-perfluorooctansulfonamido-ethyl acrylate 1%, and the Lupersol 101 / Lupersol 130 0.02% the flow speed. The temperature profile of the extruder for each of the ten 160 mm long zones was: Zone 1 = 25 ° C, Zone 2 = 77 ° C, Zone 3 = 184 ° C, Zone 4 = 180 ° C, Zone 5 = 190 ° C, Zone 6 = 205 ° C, Zone 7 = 203 ° C, Zone 8 = 200 ° C, Zones 9 and 10 = 201 ° C, end cap = 199 ° C, and fusion pump = 200 ° C . Zone 8 was ventilated under vacuum. The Aspun PE6806 grafted extruded from a strand die in a cooling bath with water and the material was then converted into pellets or spheres of generally cylindrical shape of approximately 3 mm in length and 1.5 mm in diameter. The pellets were then dried in an oven for 4 hours at 66 ° C to remove residual moisture. The pellets of grafted Aspun PE6806 were fed to the die in multiple piping by a Killion single screw extruder of 3.1 cm having a Zone 1 = 180 ° C, Zone 2 = 188 ° C, Zone 3 = 190 ° C, and Zone 4 = 206 ° C. The temperature of the multiple piping die was 190 ° C and the extrudate was drawn to a vertical contact point where the release coating was against a smooth silicone roll and the adhesive was against a chromium roller at 19 ° C, the which was wrapped with a film coated with silicone. The liner was run at 10 meters per minute and the extruder flow rates were balanced to give a protective article having a total thickness of 75 μm. The low adhesion filler was 18 μm, the reinforcement was 42 μm, and the pressure sensitive adhesive was 15 μm thick. The ability to 'recycle' the protective articles of the invention was demonstrated by the protective article of this example in a Haake 1.cm extruder having a 12.7 cm wide die, a 125 μm die hole, and the following temperature profile in the different zones: Zone 1 = 180 ° C, Zone 2 = 202 ° C, Zone 3 = 210 ° C, die = 210 ° C. No gels were found after visual examination of the extruded sheet. The leaf was considered useful as a material that could be recycled into several products.

Comparative Example 1 Comparative Example 1 was prepared as described in conjunction with Example 1, except that the adhesive did not include Escorene PP-3505G.

Comparative Example 2 Comparative Example 2 was prepared as described in conjunction with Example 1, except that the adhesive did not include Escorene PP-3505G and Eastoflex D-127S was used in place of the polyhexene.

Comparative Example 3 Comparative Example 3 was Polymask 2476, an adhesive coated article commercially available from The Polymask Corporation, Conover, N.C. to protect automotive vehicles during manufacturing, transportation and storage.

Examples 7 to 12 Examples 7 to 12 were prepared by the coextrusion of a pressure sensitive adhesive, a reinforcement, and a low adhesion filler. In each example, the pressure sensitive adhesive was a mixture of polyhexene and Escorene PP-3505G polypropylene. The IV of the polyhexene and the relative percentages by weight (% by weight) of the polyhexene and polypropylene are shown below in Table 1. The reinforcement in each example was the same and comprised 80 parts of SRD7-C55H, 20 parts of Ampacet. LR85637, and 5 parts of Ampacet 40857. (In Examples 7 to 12"parts" do not refer to "parts by weight"). The low adhesion load in each example was the same as that used in Example 6. More specifically, the pressure sensitive adhesive was prepared by the composition of polyhexene and polypropylene in a continuous process by feeding the molten polyhexene. and the granular polypropylene to a 34 mm Leistritz counter-rotating twin screw extruder (Leistritz LSM 30.34 GC, Nurenberg, Germany, length to diameter ratio = 35) at such a feed rate that it provided the desired weight ratio of polyhexene to polypropylene . For Examples 7 to 9, the 18 temperature zones of the extruder were all adjusted to 177 ° C. For Examples 10 to 12, the 18 temperature zones of the extruder were all adjusted to 193 ° C. The composite adhesive was then fed to a 3 layer Cloeren feed block. The ingredients for the reinforcement were fed to the Cloeren feed block through a Killion extruder of 31.75 mm which had the temperature zones of Zone 1 = 163 ° C, Zone 2 = 202 ° C, and Zones 3 and 4 = 232 ° C. The ingredients for the low adhesion charge were fed to the Cloeren feed block through a 19.05 mm Killion extruder which had Zone 1 temperature zones = 132 ° C, Zone 2 = 166 ° C, and Zones 3 and 4 = 177 ° C. The pressure sensitive adhesive, the reinforcement and the low adhesion filler were put together as they entered the feed block, and were extruded on a roll of chrome laminate with the reinforcement near the chromium roller. The resulting protective adhesive article was wound around a pick-up roller. The thickness of the low adhesion filler was about 2.5 μm, the thickness of the reinforcement was about 53 μm, and the thickness of the pressure sensitive adhesive was about 20 μm.

Table 1 Examples 13 to 16 Examples 13 to 16 were prepared by the coextrusion of a pressure sensitive adhesive, a reinforcement, and a low adhesion filler as described in conjunction with Examples 7 to 12, except that the polyhexene was replaced with 2.8 IV polyokene. and the 18 temperature zones of the Leistri.tz extruder were adjusted to 193 ° C. The relative percentages by weight of the polyoxethane and polypropylene are shown in Table 2 below.

Table 2 Test Procedures Examples 1 to 16 and Comparative Examples (EC.) 1 to 3 were tested to evaluate their usefulness in protecting automotive vehicles from the damage that could occur during manufacturing, transportation and storage. More specifically, these examples were evaluated for printing to paint (for example, the tendency of the article to leave a pattern printed on a surface of a painted automotive vehicle), the transfer of adhesive to the surface of a painted automotive vehicle, and the addition of the film to the surface of a painted automotive vehicle, under different conditions. The test procedures are described more fully below and the results of these tests are shown in Table 3 below.

General Preparation of Test Panels Painted Panels were prepared to simulate the surface of a painted automotive vehicle. More specifically, 10 cm (4 inches) x 30 cm (12 inches) prefabricated cold rolled steel panels having a corrosion inhibiting coating (ED-5000) were obtained from Advanced Coating Technologies, Inc., Hillsdale, Michigan. , available from PPG Industries, Cleveland, Ohio), covered with a black paint basecoat (Black 872AB921, available from EI DuPont of Nemours Company, Inc.) and overcoated with a clear protective coating (RK 7103, available from E. DuPont de Nemours Company, Inc.). A 5 cm (2 in) x 30 cm (12 in) section of the panel was masked and the remaining area of the panel was sprayed with a highly catalyzed repair paint (RK 7103 Low Bake Version, available from EI DuPont de Nemours Company, Inc.). The painted panel was cured at approximately 82-93 ° C (180-200 ° F) for approximately 30 minutes. The crosslink density of the repair paint is typically much lower than in those paints used and cured during the manufacture of the original equipment (which was simulated by the masked portion of the painted panel). Due to the low density of crosslinking, paints for preparation are more likely to exhibit viscoelastic flow and are therefore more susceptible to surface impressions that could be caused by a protective article covering them.

Paint Printing Test A 25 mm x 120 mm sample of the protective article was adhesively applied with thumb pressure to the painted test panel, through repair paint and original equipment paint surfaces. A corner of the protective article on the painting for repair was lifted, placed 15 mm from the remaining corner on the paint for repair, and again pressed with the thumb to form a fold or fold in the article. The process was repeated for the surface painted with original equipment, from the panel. Comparative Example 3 was similarly applied. The tape panel was then placed in an oven at 80 ° C for 24 hours, removed from the oven, and allowed to cool to room temperature for 2 hours. The tapes were removed manually and the depth and sharpness of the printing of the paint in the folded areas of the test panel were visually examined and qualified. It was considered that the protective articles of the invention had passed this test if the folded areas showed less swelling or topological surface change than the commercially available material of Comparative Example 3.

Adhesive Transfer The adhesive transfer refers to the adhesive residue remaining on the painted surface after removal of the protective article, and may result from an adhesive having low cohesive strength, high coating adhesion, too much viscoelastic flow, or combinations thereof. The protective article to be tested was applied to a panel prepared according to the procedure of "General Preparation of a Painted Test Panel" and to the "Paint Printing Test". The protective article was removed from the panel and examined for visible adhesive residue. A panel was considered to pass the test if there was no visible evidence of adhesive residue on the original equipment paint and surfaces with repair paint.

Adhesion of the film at 180 ° A 25 mm x 150 mm sample of the protective article to be tested was adhesively applied using thumb pressure to a test panel that had been prepared according to the procedure of "General Preparation of a Painted Test Panel" and then It was cleaned by rubbing with isopropanol using a clean, free cloth. Once applied, the protective article was free of bubbles and the adhesive was in intimate contact with the panel. After a residence time of 24 hours at room temperature, adhesion of the film to the paint surface of the original equipment was determined by fastening the panel on the jaws of an Instron tension tester and detaching the tape away from the panel at an angle of 180 ° at a crosshead speed of 300 mm / minute. The adhesion value of the film was recorded in grams / 25 mm. Preferably, the adhesion of the film is less than 1000 grams / 25 mm.

Adhesion of the Film to 180 °, Aged The sample was prepared and tested as described in the "Adhesion of 180 ° Film" test. Before measuring the adhesion of the film to the paint surface of the original equipment, The sample was aged at 80 ° C for 24 hours in an air circulation oven, removed from the oven, and allowed to cool to room temperature for 1 hour. Preferably, the aged adhesion is less than 1000 grams / 25 mm. fifteen Table 3 (continued) These data show that the protective adhesive articles according to the invention have good initial adhesion to painted metal surfaces, but can also be easily removed without leaving adhesive residue and without printing the painted surface.

Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the spirit and scope of the invention. It should be understood that this invention is not limited to the illustrative embodiments described herein.

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 (14)

1 . An adhesive article, characterized in that it comprises: a) a reinforcement or backing having opposite upper and lower surfaces; and b) a pressure sensitive adhesive on the bottom surface of the backing, the pressure sensitive adhesive comprises: 1) a substantially uncrosslinked poly-α-olefin polymer, having an inherent viscosity of about 1.0 to 5.0 dl / g and selected from the group consisting of polyhexene, polyokene, a copolymer of hexene and octene, a copolymer of hexene and propylene, a copolymer of octene and propylene, and mixtures thereof; and 2) an effective amount of a cold flow restriction agent.

2. An adhesive article according to claim 1, characterized in that the substantially non-crosslinked poly-α-olefin polymer has a polydispersity index of less than or equal to about 10.

3. An adhesive article according to claim 1, characterized in that the cold flow restriction agent has a softening point of at least about 80 ° C

4. An adhesive article according to claim 1, characterized in that the cold flow restriction agent is selected from the group consisting of polyethylene, polypropylene, ethylene vinyl acetate, blends of a polyolefin and a thermoplastic elastomer, block copolymer of styrene-butadiene-styrene, styrene-isoprene-styrene block copolymer and styrene-ethylene / butylene-styrene block copolymer.

5. An adhesive article according to claim 4, characterized in that the cold flow restriction agent is polypropylene.

6. An adhesive article according to claim 1, characterized in that the cold flow restriction agent comprises about 5 to 30 parts by weight per 100 parts by weight of the poly-α-olefin polymer.

7. An adhesive article according to claim 6, characterized in that the cold flow restriction agent comprises about 15 to 20 parts by weight per 100 parts by weight of the poly-α-olefin polymer.

8. An adhesive article according to claim 1, characterized in that the reinforcement has a tensile strength of about 210.92 to 421.84 kg / cm2 (3,000 to 6,000 psi).

9. An adhesive article according to claim 1, characterized in that the reinforcement is a material selected from the group consisting of impact modified polypropylene, polypropylene homopolymer mixed with low density polyethylene, and polyethylene-polyoxyethane copolymer mixed with low polyethylene. density.

10. An adhesive article according to claim 1, characterized in that the poly-α-olefin polymer is polyhexene with an inherent viscosity of about 1.5 to 2.6 dl / g.

11. An adhesive article according to claim 1, characterized in that the poly-α-olefin polymer is polyokene with an inherent viscosity of about 1.5 to 3.2 dl / g.

12. An adhesive article according to claim 1, characterized in that it is adhesively bonded to a painted surface of a motor vehicle.

13. An adhesive article according to claim 12, characterized in that it can be removed from the painted surface of the automotive vehicle without leaving visible traces of the pressure-sensitive adhesive on the painted surface, and without printing the painted surface.

14. The use of an adhesive article according to any preceding claim, characterized in that it is for the protection of a motor vehicle from damage during manufacture, transportation or storage thereof.