MXPA98007324A - Methods for manufacturing viscoelasti compositions - Google Patents

Abstract

Methods for the preparation of viscoelastic compositions (e.g., adhesives such as hot melt adhesives) in which a foreseeable composition (e.g., a preadhesive composition) is combined with a packaging material and then polymerized are described.

Description

METHODS FOR MANUFACTURING VISCOELASTIC COMPOSITIONS BACKGROUND OF THE INVENTION The present invention relates to the preparation of viscoelastic compositions. Methods for the manufacture of packaged viscoelastic compositions, such as hot melt adhesives and the resulting packaged compositions, are known. German Patent No. 36 25 358 discloses a block of hot melt adhesive, in a thermoplastic film. The film is melted and mixed with the adhesive in an extrusion process. U.S. Patent No. 5,257,491 discloses a method for packaging a thermoplastic or thermosetting hot melt adhesive, wherein a portion of an adhesive composition is surrounded with a plastic packaging material. The packaging material or plastic packaging does not substantially adversely affect the adhesive characteristics of a molten mixture of the adhesive and the plastic packaging or packaging material. ref. 28206 PCT International Publication No. WO 93/23224 discloses a method for packaging or packaging hot melt adhesive compositions in which the hot melt adhesive, cast, is cast into a mold coated with a plastic film. The plastic film is meltable with the adhesive composition and can be mixed in the melted adhesive composition. A method for the production of molding materials, thermoplastics, useful for producing molded articles, is described in German Patent Description 1 694 837, published July 29, 1971. In the method described, the polymerization material is allowed to polymerize in a hollow profile that functions as a polymerization vessel. The hollow profile can be made from the same polymer produced in the polymerization process. Methods for the production of hot melt adhesives in sealed reaction vessels are known. US Patent No. 4,810,523 discloses a method for the production of hot melt adhesives in which a polymerizable monomer composition is introduced into a sealable reaction vessel and polymerized by ionizing radiation. The adhesive is then removed from the reaction vessel prior to hot melt application. The reaction vessel can be a pressure vessel, cylindrical, coated, or a multi-layer bag. See column 8, line 58, to column 9, line 8, of the North American Patent No. 4,810,523. Although methods for producing viscoelastic compositions such as hot melt adhesives and methods of packaging or packaging such compositions are known, there is a need for a simplified process for making such compositions.

BRIEF DESCRIPTION OF THE INVENTION In a first aspect, the invention characterizes a method for the formation of a hot melt adhesive composition, which includes the steps of: a) the combination (i) of a pre-adhesive composition which after exposure to the transmissive energy is polymerized to form a hot melt adhesive composition and (ii) a packaging or packaging material to form a pre-adhesive packaged composition, the packaging material is selected such that it does not substantially adversely affect it. the adhesive properties of the hot melt adhesive composition, when the hot melt adhesive composition and the packaging material are melted and mixed together; and b) exposing the packaged pre-adhesive composition to transmissive energy, to polymerize the pre-adhesive composition, to form a hot melt, packaged adhesive composition. The packaged hot melt adhesive composition can then be melted if desired. In a second aspect, the invention characterizes a method for the formation of a viscoelastic composition that includes the steps of: a) the combination (i) of a prediccoelastic composition which after exposure to transmissive energy, is polymerized to form a viscoelastic composition and, (ii) a packaging material or packaging to form a packaged pre-viscoelastic composition, the packaging material is selected such that it does not substantially adversely affect the viscoelastic properties of the composition viscoelastic, when the viscoelastic composition and the packaging material are melted and mixed together; and b) exposing the packaged pre-viscoelastic composition to transmissive energy to polymerize the pre-viscoelastic composition, to form a packaged viscoelastic composition. In a third aspect, the invention characterizes a method for the formation of an adhesive composition that includes the steps of: a) the combination (i) of a pre-adhesive composition which after exposure to ultraviolet radiation, to the thermal conduction, or a combination thereof, is polymerized to form an adhesive composition and (ii) a packaging material to form a pre-adhesive packaged composition, substantially surrounding the pre-adhesive composition with the packaging material; and b) exposing the pre-adhesive composition packaged to the ultraviolet radiation, to the thermal conduction, or to a combination thereof for polymerizing the pre-adhesive composition, to form a packaged adhesive composition. The packaged composition can then be melted if desired.

A fourth aspect of the invention features a method for the formation of a hot melt adhesive composition that includes the steps of: a) placing a pre-adhesive composition on the surface of a sheet, which after the exposure the transmissive energy is polymerized to form a hot melt adhesive composition; b) exposing the pre-adhesive composition to transmissive energy to polymerize the pre-adhesive composition to form a hot melt adhesive composition; c) removal of the sheet from the hot melt adhesive composition; and d) melting the hot melt adhesive composition. The pre-adhesive composition is preferably placed on the sheet in the form of a layer having a thickness in the range of 1.2 to 8 mm. Examples of preferred sheets include flexible thermoplastic sheets. According to a preferred embodiment, the pre-adhesive composition is placed between a pair of sheets (for example, flexible thermoplastic sheets), and the two sheets are removed before melting the hot melt adhesive composition. In a preferred embodiment, the method includes the steps of placing the molten, hot melt adhesive composition on the surface of a sheet to form a sheet coated with hot melt adhesive, and exposing the sheet coated with the melt adhesive. in hot, ultraviolet radiation or ionizing radiation to form a sheet coated with pressure sensitive adhesive. For example, the method may include the steps of exposing the pre-adhesive composition to ultraviolet radiation, characterized by a first "maximum wave length" (e.g., in the range of 220 to 400 nanometers, with an average luminous intensity in - the range of 0.01 to 20 mW / cm2) to polymerize the pre-adhesive composition, to form a hot melt adhesive composition, the removal of 1-a sheet from the hot melt adhesive composition, the placement of the composition hot-melt adhesive, melted, on the surface ie a sheet, to form a sheet coated with hot-melt adhesive, and the exposure of the sheet coated with the hot-melt adhesive to ultraviolet radiation, characterized by a second maximum wavelength and / or intensity different from the first maximum wavelength and / or intensity (for example, in the range of 2.80 to 400 nanometers, with an average luminous intensity or in the range of 20 to 200 mW / cm2) to form a sheet coated with pressure sensitive adhesive. The hot melt adhesive composition preferably has a weight average molecular weight in the range of 100,000 to 1, 500,000. Additional features and advantages of the invention will be described in the following description, and in part will be apparent from the description, or can be learned by the practice of the invention. The objects and other advantages of the invention will be ascertained and achieved by the methods and articles particularly indicated in the written description and in the claims thereof. It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory, and are intended to provide additional explanation of "the invention, as claimed.

DETAILED DESCRIPTION OF THE INVENTION The present invention provides methods for the manufacture of packaged or packaged viscoelastic compositions, in which the packaging material is either retained after the polymerization (and thus becomes part of the final product) ("Type I Composition "), or is removed after polymerization and before subsequent processing (" Type II Composition "). The two types of products will be explained separately later. The description of the two types of products will be made with particular reference to the hot melt adhesive compositions. However, the principles described below are equally applicable to other types of viscoelastic compositions, including pressure sensitive adhesives in general, processable hot melt sealants, vibration damping materials, and gels for medical applications. .

Compositions Type I The present invention provides a method for the manufacture of a hot melt adhesive, packaged, thermoplastic or thermosettable, comprising: a) the provision of a pre-adhesive composition, which after exposure to transmissive energy is polymerized to provide a thermoplastic or thermosetting hot melt adhesive; b) substantially enclosing the pre-adhesive composition with a packaging material; c) the exposure of the pre-adhesive composition to the transmissive energy, capable of polymerizing the pre-adhesive composition; and d) allowing the polymerization of the pre-adhesive composition to occur to provide the hot melt, thermoplastic or thermosetting adhesive. The packaging material is selected such that it does not substantially adversely affect the desired adhesive properties of the hot melt adhesive composition, when the hot melt adhesive composition and the packaging material are melted and blended together. Preferably, a hot melt coated mixture of the adhesive and the packaging material has a storage modulus, when measured in torsional cut at 25 ° C and at 1 radian / second, between 104 and 108 dynes / cm2, and (in the case of vibration damping materials) a loss factor of at least 0.01, more preferably 0.05 to 10. The desired adhesive properties are determined by the requirements of the end user; the desired adhesive properties include peel strength and cut resistance. The pre-adhesive composition is preferably polymerized to provide a hot melt, thermoplastic adhesive after exposure to transmissive energy. The invention also provides a method for the manufacture of two or more packages of a hot melt, packaged, thermoplastic or thermosetting adhesive. In this method, two or more portions of a pre-adhesive composition are provided, and each of the portions is completely surrounded by a packaging material. These portions are then polymerized as described above. In a preferred embodiment, the pre-adhesive composition is completely surrounded by the packaging material, preferably from 0.1 to 500 g of the pre-adhesive composition are completely surrounded by the packaging material. In another preferred embodiment, from 3 to 100 g of the pre-adhesive composition are completely surrounded by a packaging material. In yet another embodiment of the invention, the "pre-adhesive composition is substantially surrounded by the packaging material." In another embodiment, the pre-adhesive composition is placed on the surface of a sheet, or between a pair of sheets substantially Parallels of the packaging material In yet another embodiment of the invention, the pre-adhesive composition is substantially or completely surrounded by a hollow profile of the packaging material with a length ratio: square root of the cross-sectional area, of at least 30 cm. The pre-adhesive composition preferably has a melting point of 40 ° C or less, more preferably 25 ° C or less.In a preferred embodiment, the melting point of the pre-adhesive composition is 0 ° C. or less, the "pre-adhesive composition preferably has a viscosity at 25 ° C of less than 50,000 centipoise, more preferably 5,000 centipoise. When the pre-adhesive composition is a non-filled monomer mixture, a viscosity of less than 50 centipoise at 25 ° C is preferred. The pre-adhesive composition can be a monomer mixture or a prepolymer mixture. A prepolymer mixture is a syrup formed by the partial polymerization of the monomeric materials that can be polymerized to form a hot melt adhesive. Preferably, the monomeric materials can be polymerized to form a pressure sensitive adhesive composition, hot melt. A small amount of non-polymerizable, volatile solvent may be included in the pre-adhesive composition to dissolve other additives, such as the cross-linking agent. The pre-adhesive composition preferably contains less than 10 weight percent of solvent. In a preferred embodiment, the pre-adhesive composition contains less than 5 percent by weight of solvent, and in another preferred embodiment, the pre-adhesive composition contains less than 1 percent by weight of solvent. The pre-adhesive composition is essentially solvent-free The preferred materials for the production of a hot-melt pressure sensitive adhesive include acrylate and methacrylate polymers or copolymers Such polymers can be formed by polymerization of 50 to 100 parts by weight of one or more acrylic or methacrylic monomeric esters of non-tertiary alkyl alcohols, with alkyl groups having from 1 to 20 carbon atoms (eg, from 3 to 18 carbon atoms) The suitable acrylate monomers they include methyl acrylate, ethyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, isooctyl acrylate, acrylate, octadecyl ilate, nonyl acrylate, decyl acrylate, isobornyl acrylate, and dodecyl acrylate. Also useful are aromatic acrylates, for example, benzyl acrylate and cyclobenzyl acrylate. In some applications, it may be desirable to use less than 50 parts by weight of the monomeric acrylic or methacrylic esters. For example, in the case of gels for medical applications, for example, bioelectrodes, the amount of the monomeric acrylic or methacrylic ester may be in the range of 0 to 50 parts by weight. Optionally, one or more monoethylenically unsaturated comonomers can be polymerized with the acrylate monomers, in amounts of 0 to 50 parts of comonomer. One class of useful comonomers includes those having a vitreous transition temperature of the homopolymer, greater than the glass transition temperature of the acrylate homopolymer. Examples of suitable comonomers falling within this class include acrylic acid, acrylamide, methacrylamide, substituted acrylamides such as N, N-dimethyl-acrylamide, itaconic acid, methacrylic acid, acrylonitrile, methacrylonitrile, vinyl acetate, N-vinyl pyrrolidone. , isobornyl acrylate, cyanoethyl acrylate, N-vini Icaprolactam, maleic anhydride, hydroxyalkyl acrylates, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylacrylamide, beta-carboxyethyl acrylate, vinyl esters of neodecanoic, neononanoic acids , neopentanoic, 2-ethylhexanoic, or propionic (for example, available from Union Carbide Corporation of Danbury, Connecticut under the designation "Vynates"), vinylidene chloride, styrene, vinyl toluene, and vinyl alkyl ethers. A second class of useful comonomers includes those having a vitreous transition temperature of the homopolymer lower than the glass transition temperature of the acrylate homopolymer. Examples of suitable comonomers falling within this class include ethoxyethoxyethyl acrylate (Tg = -71 ° C) and methoxypolyethylene glycol 400 acrylate (Tg = -65 ° C, available from Shin Nakamura Chemical Co., Ltd. under the designation " NK Ester AM-90G "). Depending on the polymerization method, the pre-adhesive composition may include an appropriate initiator. For the polymerization by ultraviolet light a photoinitiator is included. Useful photoinitiators include substituted acetophenones such as benzyl-dimethyl ketal and 1-hydroxycyclohexyl-phenyl-ketone, substituted alpha-ketoles such as 2-methyl-2-hydroxypropiophenone, benzoin ethers such as benzoin methyl ether, isopropyl ether of benzoin, substituted benzoin ethers such as anisoin methyl ether, aromatic sulfonyl chlorides, and photoactive oximes T The photoinitiator can be used in an amount of 0.001 to 5.0 parts by weight per 100 parts of the total monomer, preferably 0.01 to 5.0 parts by weight per 100 parts of the total monomer, and more preferably in an amount of 0.1 to 0.5 parts by weight per 100 parts of the total monomer.

For thermal polymerization, a thermal initiator is included. Thermal initiators useful in the present invention include, but are not limited to, azo, peroxide, persulfate and redox initiators. Suitable azo initiators include, but are not limited to, 2,2-azobis (2,4-di-ethylvaleronitrile) (VAZO 52); 2,2-azobis (isobutyroni trilo) (VAZO 64); 2, 2-azobis-2-methylbutyrylinitrile (VAZO 67); and (1,1-azobis (1-cyclohexanecarbonitrile) (VAZO 88), all of which are available from DuPont Chemicals, and 2,2-azobis (methyl isobutyrate) (V-601) and 2,2-azobis dihydrochloride (2-amidinopropane) (V-50) available from Wako Chemicals Also suitable is 2,2-azobis (4-methoxy-2,4-dimethylvaleronium trile), formerly available from DuPont Chemicals as VAZO 33. The peroxide initiators Suitable include, but are not limited to, benzoyl peroxide, acetyl peroxide, lauroyl peroxide, decanoyl peroxide, dicetyl peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate.

(PERKADOX 16S, available from AKZO Chemicals), di (2-ethylhexyl) peroxydicarbonate, butyl peroxypivalate (Lupersol 11, available from Atochem), t-butylperoxy-2-ethylhexanoate (Trigonox 21-C50, available from Akzo Chemicals, Inc.), and dicumyl peroxide. Suitable persulfate initiators include, but are not limited to, potassium persulfate, sodium persulfate, and ammonium persulfate. Suitable redox (oxide-reduction) initiators include, but are not limited to, combinations of the above persulfate initiators with reducing agents such as sodium metabisulfite and sodium bisulfite; systems based on organic peroxides and tertiary amines (for example, benzoyl peroxide plus dimethylaniline); and systems based on organic hydroperoxides and transition metals, for example, cumene hydroperoxide plus cobalt naphthenate. Other initiators include, but are not limited to, pinacols, such as 1,1,2,2-tetraphenyl ethane diol. Preferred thermal free radical initiators are selected from the group consisting of azo compounds and peroxides. More preferred are Lupersol 11 and Perkadox 16, and mixtures thereof. The thermal initiator may be used in an amount of 0.01 to 5.0 parts by weight per 100 parts of the total monomer, preferably 0.025 to 2 weight percent. A combination of thermal initiation and photoinitiation can also be used to prepare compositions according to the invention. For example, the pre-adhesive composition can be polymerized, for example, in a reactive extruder, at a certain conversion using a thermal initiator, the resulting composition (still in the pre-adhesive state) combined with the packaging material (e.g. in the form of a bag or shell) and a photoinitiator, and the polymerization is completed after exposure to ultraviolet radiation. Conversely, the initial polymerization can be initiated by a photoinitiator, and the polymerization is subsequently completed using a thermal initiator. The thermal initiator and the photoinitiator can also be used together, instead of being added sequentially. Preferably, the composition also includes a chain transfer agent for controlling the molecular weight of the polymer. Chain transfer agents are materials that regulate free radical polymerization and are generally known in the art. Suitable chain transfer agents include halogenated hydrocarbons such as carbon tetrabromide, sulfur compounds such as lauryl mercaptan, butyl mercaptan, ethanethiol, isooctylthioglycolate (IOTG), 2-ethylhexyl thioglycolate, 2-ethylhexyl mercaptopropionate, 2-mercaptoimidazole, and 2-mercaptoethyl ether, and solvents such as ethanol, isopropanol, and ethyl acetate.The amount of the chain transfer agent which is useful, depends on the desired molecular weight and the type of chain transfer agent. The solvents are useful as chain transfer agents, but these in general are not as active for example as the sulfur compounds. The chain transfer agent is typically used in amounts of 0.001 parts to 10 parts by weight per 100 parts of the total monomer, and preferably from 0.01 parts to 0.5 parts, and more preferably from 0.02 parts to 0.20 parts. A preferred pre-adhesive composition comprises: a) 50 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 1 to 20 (for example 3 a 18) carbon atoms; b) from 0 to 50 parts by weight of a polymerizable component comprising at least one modification monomer, different from the acrylic or methacrylic ester, copolymerizable with component (a), representing the sum of (a) and (b) 100 parts in weigh; c) an effective amount of a polymerization initiator; and d) an effective amount of a chain transfer agent. The polymerization initiator is preferably a photoinitiator or a thermal initiator. The pre-adhesive composition may further comprise a. effective amount of a crosslinking agent that can be activated after the adhesive has been hot melt coated. Typically, the amount is in the range of 0.01 to 5.0 parts based on 100 parts of components (a) plus (b). The crosslinking agent can be added to the polymerized adhesive before or during the hot melt coating, or it can be added to the pre-adhesive composition. When added to the pre-adhesive composition, the crosslinking agent can remain intact as a separate species in the adhesive, or can be copolymerized with the monomers. The crosslinking is preferably initiated after the hot melt coating, and the crosslinking is preferably initiated by ultraviolet radiation, or ionizing radiation such as gamma radiation or electron beam (the use of separate crosslinking agents is optional in the case of radiation ionizing). Preferred crosslinking agents that can be added after the polymerization and before the hot melt coating include • the multifunctional acrylates such as 1,6-hexanediol diarylate and trimethylolpropane triacrylate, and substituted triazines such as 2,4-bis (trichloromethyl) -6- (4-methoxyphenyl) -s-triazine and 2,4-bis (trichloromethyl) -6- (3,4-dimethoxy phenyl) -s-triazine, as described in U.S. Patent Nos. 4,329,384 (Vesley et al.) And 4,330,590 (Vesley). Yet another class of preferred crosslinking agents are the monoethylenically unsaturated aromatic ketone comonomers, copolymerizable, free of orthoaromatic hydroxyl groups, such as those described in US Patent No. 4,737,559 (Kellen et al.). Specific examples include para-acryloxybenzophenone, para-acryloxyethoxybenzophenone, para-N- (methylacryloxyethyl) -carbamoylethoxybenzophenone, para-acryloxyacetophenone, orthoacryl lamidoacetophenone, acrylated anthraquinones, and the like. Another suitable crosslinking agent is 1,5-bis (4-benzoylbenzoxy) pentane. Also suitable are hydrogen subtraction carbonyl such as anthraquinone, benzophenone, and derivatives thereof, as described in Martens et al. In US Patent No. 4,181,752. The acrylate copolymers can be crosslinked by exposure to ultraviolet radiation, for example from medium pressure mercury arc lamps. It is preferred that the crosslinking agents activated by ultraviolet radiation are mainly activated by a different wavelength of energy than that used for the polymerization. For example, low intensity black lights can be used for polymerization - and mercury arc lamps can be used for subsequent crosslinking. The pre-adhesive composition may further include thickener resins to increase tackiness of the adhesive. Thickening resins can also be added during the hot melt coating step. Suitable thickener resins include turpentine resin esters, terpenes, phenols, and pure aliphatic, aromatic hydrocarbon resins, or mixtures of synthetic aliphatic and aromatic hydrocarbons. Examples of useful thickener resins that are commercially available include Foral 85 and hydrocarbon resins sold under the trade name Regalrez by Hercules, Inc., ECR-180 available from Exxon Chemicals, and SP553, terpene phenolic resin available from Schenectady International, Inc. If used, the amount of thickener resin may be in the range of 1 part to 50 parts by weight per 100 parts of the total monomer. In some cases, the polymers can be dissolved in the monomers before polymerization, to modify the adhesive characteristics, or to make a syrup or monomer mixture. Examples of such polymers include pressure sensitive silicone adhesives, acrylic polymers and copolymers, ethylene vinyl acetate copolymers, acrylonitrile copolymers, and copolymerizable macromonomers such as those described in US Patent No. 4,554,324 (Hus an et al.). Other additives may be included in the pre-adhesive composition, or added to the hot melt coating time to change the properties of the adhesive. Such additives, or fillers, include plasticizers, pigments, bubbles or spheres of glass or polymer (which can be expanded or not expanded), fibers, reinforcing agents, hydrophobic or hydrophilic silica, calcium carbonate, stiffening agents, fire retardants, antioxidants, finely ground polymer particles such as polyester, nylon, and polypropylene, and stabilizers. The additives are added in sufficient quantities to obtain the desired final properties. The packaging or packaging material is made of a material that when combined with the adhesive, does not substantially adversely affect the desired characteristics of the adhesive. A hot-melt coated adhesive produced from a mixture of the adhesive and the packaging material may have improved adhesive properties compared to the hot melt-coated adhesive produced from the adhesive alone. In one embodiment of the invention, the pre-adhesive composition is substantially surrounded with the packaging material; In yet another embodiment of the invention, the pre-adhesive composition is completely surrounded with the packaging material. In this embodiment, it is intended that the pre-adhesive composition be completely surrounded by the packaging material, but random variations in production may produce occasional pre-adhesive in which the pre-adhesive composition is not completely surrounded by the material of the pre-adhesive composition. packing. In other additional embodiments, the pre-adhesive composition is placed on the surface of a sheet, or between a couple of leaves. The packaging material preferably melts at or below the adhesive processing temperature (in other words, the temperature at which the adhesive flows). The packaging material preferably has a melting point of 200 ° C or less, preferably 170 ° C or less. In a preferred embodiment, the melting point is in the range of 90 ° C to 150 ° C. The packaging material may be a flexible film of thermoplastic polymer. The packaging material is preferably selected from ethylene vinyl acetate, ethylene acrylic acid, polypropylene, polyethylene, polybutadiene, or ionomeric films. In a preferred embodiment, the packaging material is an ethylene acrylic acid or ethylene vinyl acetate film. In the practice of the invention, films in the thickness range of 0.01 mm to 0.25 mm can be used. The thicknesses are preferably in the range of 0.025 mm to 0.127 mm to obtain films that have good strength during processing, while being thin enough to heat seal rapidly and minimize the amount of film material used. The amount of packaging material depends on the type of material and the desired final properties. The amount of packaging material is typically in the range of 0.5 percent to 20 percent of the total weight of the pre-adhesive composition and the packaging material.

Preferably, the packaging material is between 2 percent and 15 percent by weight, and more preferably between 3 percent and 5 percent. Such packaging materials may contain plasticizers, stabilizers, pigments / perfumes, fillers, slip agents, antiblocking agents, flame retardants, antistatic agents, microwave susceptors, thermally conductive particles, electrically conductive particles, and / or other materials to increase the flexibility, handling ability, visibility, or other useful properties of the film, as long as these do not adversely affect the desired properties of the adhesive. The packaging material must be appropriate for the polymerization method used. For example, with photopolymerization, it is necessary to use a film material that is sufficiently transparent to ultraviolet radiation at the wavelengths necessary to effect polymerization. The transmissive energy can be selected from ultraviolet radiation, visible radiation, thermal radiation, or thermal conduction. The transmissive energy is preferably ultraviolet radiation or thermal conduction. Preferably, at least 80 percent of the pre-adhesive is converted to adhesive, more preferably at least 90 percent of the pre-adhesive is converted to adhesive.The thermal polymerization can be effected by immersing the composition packaged in a medium of heat exchange at temperatures between about 40 ° C and 100 ° C for a sufficient time to polymerize the composition.The heat exchange medium can be a forced or shocked gas or a liquid such as water, perfluorinated liquids, glycerin, or propylene glycol The heat required for thermal polymerization can also be provided by a metal platform, heated metal rollers, or microwave energy.The temperature at which the polymerization occurs depends on the activation temperature of the initiator. For example, polymerization using VAZO 64, a commercially available initiator from DuPont Company can be carried out at about 80 ° C, while Vazo 51, also available from DuPont Company, can be used at about 70 ° C. It is preferable to carry out the polymerization in an appropriate liquid heat exchange medium at a controlled temperature. A suitable liquid heat exchange medium is water, heated to the desired reaction temperature. Commercially available heat transfer fluids can also be used. Additional information concerning thermal polymerization can be found in US Patent No. Serial No. 08 / 234,468, filed on April 26, 1994, entitled "Thermal Radiation Adhesives by Free Radicals and Articles Made from Them." Polymerization can also be effected by exposure to ultraviolet (UV) radiation as described in U.S. Patent No. 4,181,752 (Martens et al.). In a preferred embodiment, the polymerization is carried out with black UV lights having above 60 percent, and preferably above 75 percent of its emission spectra between 28"0 to 400 nanometers (nm), with an intensity between 0.1 to 25 mW / cm2 During photopolymerization it is desirable to control the temperature by blowing cooling air around the packaged pre-adhesive composition, by running the pre-adhesive composition packaged on a cooled platform, or by immersion of the packaged or packaged pre-adhesive composition in a water bath or in a heat transfer fluid during the polymerization Preferably, the packaged pre-adhesive compositions are immersed in a water bath, with the water temperatures between 5 ° C and 90 ° C, preferably below 30 ° C. Agitation of water or fluid helps to avoid hot zones during the reaction In a preferred embodiment, after exposure of the pre-adhesive composition to the transmissive energy, and allowing the polymerization of the pre-adhesive composition to occur, at least a portion of the pre-adhesive solution has been converted to an adhesive comprising at least one polymer with a weight average molecular weight of at least 50,000. The weight average molecular weight of the polymerized adhesive composition may be in the range of 5.0,000 to 3,000,000, and preferably from 100,000 to 1,800,000, and more preferably 200,000 to 1,500,000. In a preferred embodiment, the Adhesive is a pressure sensitive adhesive at 25 ° C. In another preferred embodiment, a hot melt coated mixture of the adhesive and the packaging material is a pressure sensitive adhesive at 25 ° C and has a storage modulus when measured in torsional cut at 25 ° C. and 1 radian / second of between about 104 and about 107 dynes / cm2. The polymerized adhesives of the invention preferably have a storage modulus (G) when measured in the torsional cut at 25 ° C and at 1 second (or frequency of 1 radian / second) between about 104 and 108 dynes / cm2 and more preferably between approximately 104 and 107 dynes / cm2. ~ The storage module for a polymerized adhesive having a composition of 90 parts of isooctyl acrylate and 10 parts of acrylic acid is 1.58 x 106 dynes / cm2, and for an adhesive having a composition of 98 parts of isooctyl acrylate and 2 parts of acrylic acid is 2 x 105 dynes / cm2 as determined by means of a Dynamic Thermal Mechanical Analyzer (DTMA) manufactured by Polymer Laboratories. The instrument holds the sample to a small sinusoidal oscillation in - a cutting geometry. The shear storage module is measured at an oscillation frequency of 0.1 to 100 Hertz in a temperature range of -1Q0 ° C to 150 ° C at a heating rate of 2 ° C per minute according to ASTM No. D4065 -82. The polymerized adhesives can be used to make a hot melt adhesive, which can be coated, but thermoplastic or thermosetting, by introducing the adhesive and its packaging material into a container in which the adhesive and its packaging material they are melted This hot melt adhesive can be used to form a sheet of pressure sensitive adhesive, by coating the molten adhesive and its packaging material on a sheet material or other suitable substrate. The sheet material is preferably selected from a tape reinforcement or a release liner. Preferably, the polymerized adhesives are hot melt coated by placing the packaged or packaged adhesive in a hot melt coater at a temperature sufficient to melt the packaged adhesive, and with sufficient mixing to form a coatable blend, which is coated on a substrate. This step can be conveniently carried out in a hot extruder, in a bulk tank melter, on-demand melting equipment, or a hand-held hot melt adhesive gun. If a crosslinking agent is added, the coated adhesive can then be exposed to sufficient UV radiation or ionizing radiation to effect crosslinking. The crosslinking is preferably initiated after coating. The steps can be carried out online, in other words, the pre-adhesive composition can be surrounded by the packaging material, polymerized, hot-melt coated to form a tape, and optionally crosslinked, or the steps can be taken to out individually to times and in separate places. For example, the packaged pre-adhesive composition can be polymerized at a single time, and extruded and cross-linked at another time. In one embodiment of the invention, a ribbon is formed in which the substrate is a tape reinforcement. Typical belt reinforcements include cellulosic materials such as paper, pleated paper, and cloth (including woven and non-woven fabrics); films such as diaxially oriented polyester, polyvinyl chloride, polyurethane, biaxial and monoaxially oriented polypropylene, nylon, foam materials such as polyethylene foams and acrylic foams, and metal foils such as aluminum foil.The reinforcements are usually treated on the "back side, with a release coating such as silicone, and can be treated before hot melt coating, to improve adhesion of the adhesive to the reinforcement." Useful treatments for improving adhesion of the adhesive to reinforcement include Chemical Dressing and Corona Treatment In yet another embodiment of the invention, a transfer ribbon is formed wherein the substrate is a release liner.The release liner can be coated on one or both sides with a release liner, -and the transfer belt is removed from the substrate when it is used by the end user. In addition, the adhesive can be coated on one or both sides of a reinforcement to form a doubly coated tape. In yet another embodiment, the substrate is the surface "of a part to be joined to another part, with the hot melt adhesive, In still another embodiment of the invention, the adhesive or a tape made of the adhesive is used. to dampen vibrations or as a sealant In the practice of one embodiment of the invention, two lengths of the thermoplastic film are heat sealed together through the bottom and on each of the side edges on a form-fill machine. - Sealing of liquid, to form an open end bag The pre-adhesive composition is pumped through a hose to fill the bag, and the bag is then heat sealed through the top to completely surround the adhesive composition Preferably, the form-fill-seal machine is equipped with a pulse sealant to form the upper and lower seal through the bags.Such sealant has one or two groups of man Blocks that hold the bag before sealing. A sealing wire is then heated to effect the seal, and the seal is cooled before the jaws are released. "The sealing temperature is generally above the smoothing point and below the melting point of the film used to form the bag.During the sealing process, it is desirable to get most of the air out of the bag before the A small amount of air is tolerable, as long as the amount of oxygen is not sufficient to substantially interfere with the polymerization process.For ease of handling, it is desirable to seal the bags as soon as they are filled with the composition although the immediate sealing is not necessary in all cases, in some cases the pre-adhesive composition can alter the packaging material, and it is desirable to seal the bags transversely within about 1 minute of filling, more preferably within 30 seconds, and more preferably within 15 seconds.If the pre-adhesive composition decreases the strength of the packaging material, poly is preferable. Make the composition as soon as possible, after the pre-adhesive composition is surrounded by the packaging material. For the combination of the acrylate monomers with ethylene acrylic acid, ethylene vinyl acetate or ionomeric films, it is preferable to polymerize the composition within about 24 hours of bag sealing. Alternatively, a single length of film can be folded longitudinally and sealed on an edge, filled with the pre-adhesive composition, and sealed. In yet another embodiment, a simple length of film can be pulled through a forming collar, sealed to form a tube, filled with the composition, and sealed. Yet another embodiment can be carried out on commercial liquid filling-sealing machines. One source of such machines is Packaging Machinery Division of Eagle Corp. It is contemplated that the seals can be made in any of a number of different configurations to form multiple bags through and down the film lengths. For exampleIn addition to the seals on the side edges, a seal can also be formed towards the center of the "lengths of the film, so that a transverse seal will form two full pockets." The bags can either be left attached to one another by the transverse seals and / or vertical seals, or they can be cut into individual bags or bag strips.The bags can each contain the same or different compositions.The pre-adhesive composition can then be polymerized to form an adhesive within the polymer bag by any of the aforementioned methods.The adhesive within the polymer bag can be used to dampen vibrations.Alternatively, the adhesive itself can be used to dampen vibrations.In yet another embodiment of the invention, the composition adhesive is continuously introduced into a hollow profile of a polymeric film material, continuously exposed to transmissive energy capable of polymerizing said pre-adhesive composition, continuously polymerized to provide a thermoplastic or thermosetting hot melt adhesive, and the polymeric film material and its contents are continuously introduced into a container in which the polymeric film material and its contents are fused. The polymeric film material does not substantially adversely affect the adhesive characteristics of a hot melt coated mixture of the adhesive and the polymeric film material. The hot melt adhesive and the polymeric film material can be melted, mixed and coated onto a sheet material to form a sheet coated with pressure sensitive adhesive. The hollow profile of the polymeric film material is the inside of a continuous tube of polymeric film material. The continuous tube is preferably a cylindrical, elliptical, or continuous rectangular tube. In a preferred embodiment, the continuous tube is an elliptical continuous tube. In one embodiment of the invention, the tube has no transverse seals. The hollow profile of the polymeric film material preferably has a cross-sectional area of 0.5 cm 2 to 25 cm 2, more preferably 1 cm 2 to 10 cm 2. In another embodiment of the invention, the pre-adhesive composition is coated on a carrier network, covered with a sheet material, and polymerized with a transmissive energy, wherein the carrier network, the sheet material, or both, are recoverable by Hot melt with the adhesive. If the carrier network and the sheet material are hot melt coatable, the resulting composite can be fed directly into a hot melt coater, or cut into small strips or pieces and fed to the hot melt coater. only one of the carrier network or the sheet material is hot-melt-coated with the adhesive, the non-coatable entity is removed before the adhesive is hot-melt coated, to facilitate handling after the entity is removed Non-coatable, the polymerized adhesive can be folded on itself so that the coatable entity substantially surrounds the larger surfaces of the coated adhesive The adhesive network can then be fed into a hot melt coater, or it can be cut to strips or pieces smaller before the hot melt coating, if the carrier net or the sheet material is not coated with the adhesive ivo (for example, as in the case of Type II compositions, described below), this should be treated, if necessary, so that the adhesive can be easily removed from it. Such treatments include silicone release coatings, polyfluoropolyether coatings, and polyfluoroethylene coatings. The carrier network must provide sufficient strength to support the coated pre-adhesive composition during polymerization, or it can be supported by a table or platform during the polymerization. The carrier network can be an endless conveyor belt, or it can be a flexible material that can be wound on a roll with the adhesive; the carrier network is itself a sheet material. The endless conveyor belts can be made of silicone elastomers; polymeric films such as those made of polyfluoroethylene, polyester, nylon, polycarbonate, and the like; metals such as stainless steel; rubber; fiberglass; and similar. Useful flexible materials include polymeric paper and films such as those made of polyester, nylon, polycarbonates, polyolefins, ethylene acrylic acid, ethylene vinyl acetate, ionomers, and the like Flexible, recoverable materials include polyolefins such as polypropylene, polyethylene, and polyethylene. polybutadiene, ethylene acrylic acid, ethylene vinyl acetate, and ionomers Likewise, the sheet material can be manufactured from the aforementioned flexible materials, as well as non-flexible plates made of glass, polymers or metals, which can optionally be coated with a release material If the pre-adhesive composition is to be light-cured, the carrier network, the sheet material, or both must be sufficiently transparent to the actinic radiation to effect the polymerization.

In yet another embodiment of the invention, the pre-adhesive composition is coated on a carrier network and polymerized with transmissive energy; The coated pre-adhesive is not covered with a sheet material. The carrier network is recoatable with the adhesive. In a preferred embodiment, when the coated pre-adhesive is not covered with a sheet material, the polymerization is conducted in an inert atmosphere. The invention also provides a hot melt, packaged, thermoplastic or thermosetting pre-adhesive comprising a pre-adhesive composition substantially or completely surrounded by a packaging material; The pre-adhesive composition has a viscosity of less than 50,000 centipoise at 25 ° C and is capable of polymerizing in the presence of transmissive energy to provide a hot melt, thermoplastic or thermosetting adhesive. Preferably, the packaging material does not substantially adversely affect the adhesive properties of a hot melt-coated mixture of the packaging material, and an adhesive produced from the polymerization of the pre-adhesive composition, and a melt-coated mixture. In hot adhesive and packaging material, preferably has a storage module when measured in the torsional cut at 25 ° C and 1 radian / second, between about 104 and about 108 dynes / cm2. The adhesive is obtainable from the pre-adhesive composition by: a) exposing the pre-adhesive composition to transmissive energy, capable of polymerizing the pre-adhesive composition; and b) allowing the polymerization of the pre-adhesive composition to occur to provide the hot melt, thermoplastic or thermosetting adhesive. In another preferred embodiment of the packaged pre-adhesive, the pre-adhesive composition has a viscosity of less than 5,000 centipoise at 25 ° C; in another embodiment, the pre-adhesive composition has a viscosity of less than 50 centipoise at 25 ° C. The packaging material is preferably a flexible thermoplastic polymer film. The packaging material is preferably selected from ethylene vinyl acetate, ethylene acrylic acid, polypropylene, polyethylene, polybutadiene, or ionomeric films. In yet another embodiment of the packaged pre-adhesive, the pre-adhesive composition comprises: a) 50 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 1 to 20 (for example, from 3 to 18) carbon atoms; b) from 0 to 50 parts by weight of a polymerizable component comprising at least one modification monomer, different from the acrylic or methacrylic ester, copolymerizable with component (a), representing the sum of (a) and (b) ) 100 parts by weight; c) an effective amount of a polymerization initiator; and d) an effective amount of a chain transfer agent. In addition to the applications described above, packaged adhesives are useful in other areas. For example, the method described above can be used to prepare useful self-adhesive articles, for example, as labels, gummed labels, side-body molding, decorative molding, electrical tapes, patches for drug administration, mechanical fasteners (for example, SCOTCHMATEMR hook and loop fasteners and fasteners that are repeatedly locked from the DUAL LOCKMR brand, sold by the Minnesota Mining and Manufacturing Company of Saint Paul, Minnesota), abrasive articles (eg, sanding discs) , form-in-place packaging, medical tapes, films for marking canvas, and decorative sheets, and by "arranging the pre-adhesive composition between a substrate sheet and a releasable liner, polymerizing the composition, and then removing The liner The packaged or packaged adhesives can also be used on sheet products such as retroreflective sheets (eg, the retroreflective sheets based on microspheres and the leaves of the cubic corner type) and graphic sheets. Illustrative examples of retroreflective sheets on which the adhesives of the invention may be used include exposed lens retroreflective sheets, embedded lens sheets and encapsulated lens sheets. Illustrative examples of commercially available retroreflective sheets suitable for use include the SCOTCHLITE trademark, Engineering Grade, High Intensity Grade and Diamond Grade Retrofit Sheets sold by the Minnesota Mining and Manufacturing Company of Saint Paul, Minnesota.

After the selection of suitable adhesive modalities, these sheets can be applied to a variety of desired substrates, such as license plate primers, vehicle bodies, signs, ramps / protection, pavement surfaces, vehicle bodies, traffic cones, barriers, clothing and markers, etc. Illustrative examples of commercially available graphical sheets suitable for use include Vini Films and Polyester Films, SCOTCHCAL trademark of the Minnesota Mining and Manufacturing Company of Saint Paul, Minnesota.

Test Procedures-Type I Compositions MOLECULAR WEIGHT The molecular weight of. polymer is determined (before hot melt coating and crosslinking) by conventional gel permeation chromatography. The instrumentation includes a Hewlett-Packard Model 1090 chromatograph, a Hewlett-Packard Model 1047A Refractive Index Detector, and a UV variable wavelength detector set at 254 nanometers. The chromatograph was equipped with a mixed-bed pore size from Jordi Associates and a W-100 Angstrom column from Waters Associates, or two 20-micron mixed bed columns (PL Gel) from Polymer Labs. The system was calibrated to polystyrene from Pressure Chemical Co. The signal was converted to a digital response using the physical equipment (hardware) and the software (hardware) of Nelson Analytical, and the molecular weights (average in weight and average in number) and the polydispersity were determined in a Hewlett- Packard Model 9000/200. The weight average molecular weight (MW) and polydispersity (P) were calculated according to accepted practices. The polydispersity is calculated by dividing the weight average molecular weight among the number average molecular weight. The GPC test methods are further explained in "Modern Size Exclusion Liquid Chromatography: Gel Permeation Chromatography Practice", John Wiley and Sons, 1979. The samples were prepared by pretreatment with diazomethane in diethyl ether. After drying, the samples were dissolved in tetrahydrofuran (THF) at a concentration of 1.5 milligrams per milliliter of tetrahydrofuran, and filtered through a 0.2 micron Teflon filter.

The samples were injected into the columns at 50 microliter volumes and eluted at a rate of 1. ml per minute through the columns, maintained at approximately 21 ° C.

ADHESION TO DEGREES AT 90 DEGREES One of the liners is removed from a strip of the pressure-sensitive adhesive transfer tape, which measures 12.7 cm by 1.27 cm, and laminated to an aluminum sheet of 0.0508 mm (2 mils) in thickness. The other liner is then removed and the tape is adhered to a 5.08 cm by 12.7 cm stainless steel panel that had been cleaned by rubbing once with acetone and rubbing twice with heptane. The tape was wound with a pitch of a 2.05 kg hard rubber roller. The panel was conditioned at room temperature (approximately 21 ° C) for approximately 15 minutes for initial release adhesion (INIT) or 72 hours for adhesion to aged release (AGED), then mounted on a release tester such that the The tape is pulled at a 90 degree angle at a speed of 30.5 cm per minute. The results are reported in the tables in Newtons per decimeter (N / dm), and the values are an average of two tests.

STATIC CUTTING The static cut is determined by the lamination of the pressure-sensitive adhesive transfer tape, to a piece of 0.0508 mm thick aluminum sheet and cutting to a dimension of 12.7 cm by 1.27 c. One end of the sample is adhered to a stainless steel panel, previously cleaned as described above, with an overlap of 2.54 cm, and a weight is attached to the other end of the sample. The panel is then hung at approximately a 2 ° incline from the vertical, to ensure a failure in cutting mode, and the time in which the sample is detached away from the panel is measured in minutes (min). The test is discontinued after 10,000 minutes. A weight of 100 grams is used for cutting at room temperature (RT). Cutting at high temperature is conducted by hanging a group of samples in an oven at 70 ° C using a weight of 500 grams (500 g), and by hanging a second group "using a weight of JL000 grams (1000 g). reported values represent the average value of two tests per group.

HEAT SEALABLE FILMS Film A - A biaxially oriented heat-sealable polypropylene film of 0.0254 mm (1 mil) thickness was prepared by heating a film surface on a hot roll coated with Teflon polymer (DuPont 958-203) that had been polished to 0.8-1.3 micras, Ra, at a speed of 23 meters per minute. The roll surface was heated to a surface temperature of 260 ° C. The net made contact with 2-4 millimeters of the surface of the roller. The film had a surface finish of approximately 1.4 micras Ra with 41 peaks per centimeter. The surface was measured using a Surtronic 3 Profiler (from Taylor-Hossen, Leicester, England) using a needle # 1502, hit or long, and 50 bandwidth. The first joining force scored (detachment T, ASTM D1876-72) was perceived as 149 ° C and was approximately 1.5 kg / cm. The preparation of the film is described in copending US application Serial No. 08 / 047,807 (Hyde), incorporated by reference herein. Film B - A 0.0635 mm (2.5 mil) thick heat-sealable ethylene-vinyl acetate film having 6% vinyl acetate (VA24- from Consolidated Thermoplas tics Co. From Schaumburg, Illinois). Film C - A heat-sealable ethylene-acrylic acid film of Q.0635 mm (2.5 mils) thick (EA90, also designated PL50 from Consolidated Thermoplastics Co.). Film D - A film of heat sealable ethylene acrylic acid of 0.057 mm (2.25 mils) thick (EA90, also designated PL50 of Consolidated Thermoplastics tics Co.).

E emplos-Compositions Type I Example 1 Two sheets of Film A were heat sealed on side edges and the bottom to form a rectangular bag measuring 3.175 cm (1.25 inches) wide on a machine for liquid form filling and sealing. The bag was then filled with a pressure sensitive adhesive composition having 90 parts of isooctyl acrylate (IOA), 10 parts of acrylic acid (AA), 0.25 parts of benzyl-dimethyl ketal photoinitiator (Irgacure 651 from Ciba Geigy) per 100 parts of the total monomer ("PHR"), 0.05 PHR of carbon tetrabromide (CBr4), and 0.1 PHR of para-acrylobenzophenone. The filled package was then sealed by heat in the upper part in the transverse direction, through the monomer, to form individual bags measuring 3,175 cm by 3,175 cm by approximately 0.356 cm in thickness, "which contained 1.9 grams of composition." -.- The bags were placed in a water bath that was maintained between approximately 21 ° C and 32 ° C and exposed to ultraviolet radiation at an intensity of approximately 2 mW / cm2 per 8.33 minutes (UV Exposure Time). The radiation was supplied from lamps that had approximately 90% emissions between 300 and 400 nanometers (nm), and a maximum emission at 351 nm. The molecular weight (Mw) and the polydispersity (P) of the adhesive are shown in Table 1.

The bags were then fed to a single screw extruder (Haake) with barrel temperatures adjusted to approximately 177 ° C and die temperatures adjusted to approximately 177 ° C. The pressure sensitive adhesive was extruded to a thickness of 0.0508 mm on a paper web which was treated on both sides with a silicone release coating. The coated adhesive was then exposed to a medium pressure mercury vapor lamp, having a yield of approximately 80 watts per centimeter and a spectral yield in a range of 180 to 430 nm, to provide a total energy of 100 mJ / cm2. The pressure sensitive adhesive was then tested according to the test procedures described above for adhesion to detachment and static cutting. The test results are shown in Table 1.

Examples 2-5 - The pressure sensitive adhesive tapes were prepared and tested as for Example 1, except for the changes in composition and exposure times as shown in Table 1 and as follows: Example 3 contained 2.3 grams of adhesive composition. . Example 4 was prepared by mixing the adhesive composition and exposing it to ultraviolet radiation as described above, to form a pre-adhesive composition having a viscosity of about 3000 centipoise. The pre-adhesive composition was then used to fill the bags (approximately 2.2 grams / bag). Example 5 included 1.0 parts of antioxidant (Irganox 1076 from Ciba Geigy) and the "bags contained 2.3 grams of adhesive composition. s.

* PI (PHR) - Quantity of photoinitiator in parts per 100 parts of acrylate monomer and copolymerizable monomer (PHR).

The data in Table 1 show that the pressure sensitive adhesives have good adhesive properties, which can be made by the method of the invention. The adhesive compositions of Examples 1-5 were polymerized as described above using three different cooling methods: blowing with compressed air over the bags, on a platform or metal table cooled to -3.9 ° C, blowing nitrogen over the bags on a metal platform cooled to -3.9 ° C, and submerging the bags in a water bath as described above, while maintaining the exposure time to constant ultraviolet rays at 8.33 minutes. Molecular weights and polydispersions were determined and are shown in Table 2.

The results in TABLE 2 show that the polydispersity can be varied depending on the cooling method used, and cooling with a water bath is preferred when a lower polydispersity value is desired.

Examples 11-30 Examples 11-30 show various combinations of the adhesive compositions and processing conditions to change the properties of the adhesive. Pressure sensitive adhesive tapes were prepared and tested as for Example 1, except for changes in composition and exposure times as shown in Table 3 and as follows: Examples 11-13 - B film was used to form bags that measured 4.06 cm by 3.81 c by 0.66 cm in thickness. The bags contained 6.6 grams of pre-adhesive composition. The temperature of the water bath was approximately 25 ° C. Examples 14-15 - Film C was used to make bags measuring 3.18 cm long by 3.18 wide by approximately 0.36 cm thick, and which contained 2.4 grams and 2.7 grams of composition, respectively. Examples 16-17 - Film C was used to make - bags measuring 4.06 cm by 3.56 cm by 0.51 cm and containing 4.5 grams pre-adhesive decomposition. Examples 18-19 - Film C was used to make bags measuring 4.06 cm by 3.56 cm by 0.51 cm containing 5.1 grams of pre-adhesive composition.The monomeric composition was changed to 96. parts of IOA and 4 parts of AA Examples 20-22 - Film D was used to make bags measuring 4.06 cm by 3.81 cm The Example was 0.61 cm thick and contained 6.8 grams of pre-adhesive composition Examples 21-22 were 0.64 cm of thickness and contained 6.6 grams of pre-adhesive composition Examples 23-25 - Film C was used to form full bags measuring 4.06 cm by 3.81 cm by 0.64 cm in thickness The bags of Example 23 contained 7.2 grams of a composition that had 92 parts of IOA and 8 parts of AA.

Example 24 contained 6.9 grams of a composition having 94 parts of IOA and 6 parts of AA. The bags of Example 25 contained 7.0 parts of a composition having 96 parts of IOA and 4 parts of AA. Examples 26-28 - Film C was used to form filled bags measuring 4._6 cm by 3.81 cm by 0.58 cm in thickness and containing 6.7 grams of a composition having 98 parts of IOA and 2 parts of AA. Examples 29- 0 - Film C was used to form filled bags measuring 4.06 cm by 3.81 cm by 0.61 cm and containing 6.4 grams of a composition having 90 parts of IOA and 10 parts of AA. s > s.

A pressure sensitive adhesive, hot-melt coated, was prepared as in Example 26. The adhesive was then cross-linked with electron beam energy at the various doses shown in TABLE 4. The test results for adhesion to the detachment and static cut are shown in TABLE 4.

Dose per electron beam shown in Megarads. - Static cut conducted at 65 ° C with a weight of 500 grams, and a sample 1.27 cm wide with an overlap of 1.27 cm on the panel.

The data in TABLE 4 show that the pressure sensitive adhesive can be crosslinked by electron beam radiation to provide useful pressure sensitive adhesives.

Example 31 A bag measuring 6.86 by 3.30 cm was prepared by heat sealing three edges of Film A. The bag was filled with 10 grams of a pre-adhesive composition having 90 parts of IOA, 10 parts of AA, and 0.3 PHR of primer VAZO 64. Most of the "air was squeezed and the fourth edge was sealed.The bag was placed in a small capacity container filled with tap water at 60.5 ° C and a mesh length with weights coupled to each The bag was held in the water for 3 hours and 54 minutes, during which time the incoming water was added to maintain the water temperature at approximately 60 ° C. observed an increase in viscosity and the formation of some gas bubbles in the bag.The final water temperature was 59.5 ° C. The composition had been polymerized to a sticky state of the pressure sensitive adhesive that did not have gels visible. This composition can be coated with a hot melt adhesive.

Example 32 Two sheets of Film C (0.0635 mm thick film of ethylene acrylic acid) were heat sealed on the side edges to form a continuous tube (measuring 3,810 cm wide when flattened) on a machine for liquid, filling and sealed. "The tube was then continuously sealed with a pressure-sensitive adhesive composition containing 90 parts of isooctyl acrylate (IOA), 10 parts of acrylic acid (AA), 0.75 parts of benzyl-dimethyl ketal photoinitiator ( Irgacure 651 by Ciba Geigy), 0.075 parts of carbon tetrabromide and 0.1 part of para-acryloxybenzophenone The fill rate was approximately 1.7 grams of the composition per cm of tube length, and the filled tube was 0.635 cm thick The full tube without transverse seals was then pulled through a water bath that had a temperature of about 23 ° C and polymerized with ultraviolet radiation on a continuous base, such that the tube contained monomer as it entered the water bath under the ultraviolet light lamps, and the tube contained a pressure sensitive adhesive as it was removed from under the lamps. The tube was exposed to ultraviolet radiation at an intensity of approximately 2 mW / cm2 for 9 minutes and 25 seconds to polymerize the entire length of the tube. Radiation was provided from lamps that had approximately 90% emissions between 300 and 400 nanometers (nm), and a peak or maximum emission at 351 nm. The tube, which measured approximately 15 meters, contained a sticky, pressure-sensitive adhesive that had no visible gels. The tube and its contents can be hot melt coated.

Example 33 Bags were prepared as in Example 1 and filled with a series of hot-melt, acrylate, pressure-sensitive adhesive compositions. In the first pair, a composition (Al) contained 93 parts of isooctyl acrylate, 7 parts of acrylic acid, 0.60 parts of Irgacure initiator 651, 0.04 parts of carbon tetrabromide chain transfer agent, and 0.10% by weight of 4-acryloyl-oxy-benzofone (ABP), while its counterpart composition (A-2) was identical to the first composition, except that it did not contain ABP. The strong bags made from the EA90 ethylene acrylic acid film were 5 cm (2 inches) wide. The bags containing the composition A-l were exposed "to an energy of 744.3 mJ / cm2, for 8 minutes, 42 seconds, the weight of the 20 bags was 243.4 grams; the length of 20 bags was 107.3 cm (42.75 inches); The thickness of 20 bags stacked on top of each other was 5,375 inches. The polymerized adhesive in the bags had a weight average molecular weight of 780,000 and a polydispersity of 3.21. the molecular weight was determined as defined above, except that a particle size column of 10 microns ASI Permaged was used. The bags containing composition A-2 were exposed to an energy of 773.6 mJ / cm2 for 8 minutes, 44 seconds. The weight of the 20 bags was 242.3 grams; the length of the 20 bags was 107.63 cm (42.375 inches); the thickness of a stack of 20 bags was 14.28 cm (5,625 inches). The adhesive obtained a molecular weight of 594,000 and a polydispersity of 2.46. The remaining series of compositions were prepared in a similar manner with the following compositions. In the second pair, a composition (Bl) containing 93 parts of isooctyl acrylate, 7 parts of acrylic acid, 0.60 parts of Irgacure initiator 651, 0.01 parts of carbon tetrabromide chain transfer agent and 0.10% by weight of 4-acryloyloxy-benzophenone (ABP), while its counterpart (B-2) composition was identical to the first composition, except that it did not contain ABP. In the third pair, a composition (Cl) containing 93 parts of isooctyl acrylate, 7 parts of acrylic acid, 0.20 parts of Irgacure initiator 651, 0.01 parts of carbon tetrabromide chain transfer agent and 0.10% by weight of 4-acryloyl-oxy-benzophenone (ABP), while its counterpart (C-2) composition was identical to the first composition, except that it did not contain ABP. In the fourth pair, a composition (D-1) containing 93 parts of isooctyl acrylate, 7 parts of acrylic acid, 0.60 parts of Irgacure initiator 651, 0.01 parts of isooctyl thioglycol chain transfer agent, and 0.10% by weight of 4-acryloyl-oxy-benzophenone (ABP), while its counterpart composition (D-2) was identical to the first composition, except that it did not contain ABP. Each composition was hot melt coated to form a coating of approximately 127 microns (5 mils) thick, which was then crosslinked by exposure to 300 kV electron beam radiation (Compositions Al, A-2, Bl , B-2, Cl and C-2) or 240 kV (Compositions D-1 and D-2) and various doses. The gel fraction of each composition at each dose was also measured. The results are shown below in Table 5. The results show that the compositions containing ABP showed a higher gel fraction for a given dose of electron beam, as compared to the compositions without ABP.

The dose was 1.5 Megarads.

Compositions Type II ~~ In the Type II compositions, the packaging material is removed after the polymerization, so that any further processing, eg, melting, coating - or simply application - of the adhesive, involves only the adhesive. The adhesive and pre-adhesive compositions described above in the case of Type I compositions are equally suitable for Type II compositions, as are the processes and polymerization conditions used to prepare the adhesive. The packaged materials described in relation to the Type I compositions are also suitable. However, because the packaging material is removed before any post-polymerization processing, the choice of packaging material is not limited to materials that will not substantially affect the adhesive properties of the final product, when they are melted together. In this way, a wide variety of packaging materials can be used, with materials that allow easy removal of the adhesive you prefer. To improve the ability to "remove the adhesive from the packaging material, the packaging material may be provided with a release material." Examples of applications in which the packaging material is removed prior to post-polymerization processing, they include the moisture-curable sealant compositions.These compositions could be prepared in the form of a sealed pouch, which is removed to allow application of the sealant composition.Other examples include the optically clear adhesives.

Test Procedures-Type II Compositions Test tapes were prepared using the hot melt adhesive compositions according to the coated Examples on a release layer, by transferring the sample to a reinforcing layer of aluminum foil having a thickness of approximately 50 microns, to provide the tape that is going to be tested. Each tape was divided to a width of 1.27 cm. The tapes were tested for the Value of Detachment and Cutting Value as indicated below. 90 ° DETACHMENT VALUE The tape was adhered by means of its adhesive to a stainless steel plate under the weight of a 2 kg hard rubber roller. The 90 ° retro-spread is measured by coupling the free end of the tape to a scale and moving the steel plate away from the scale at a rate of about 3.8 cm per second. The samples were subjected either to a residence time of 20 minutes at room temperature (RT) or to a residence time of 20 minutes followed by 72 hours at room temperature. All samples were tested at room temperature. The test data is measured in ounces / 1-inch width and converted to Newtons / decimeter (N / dm).

CUTTING VALUE A strip of tape is adhered by means of its adhesive to a stainless steel plate under the weight of a 2 kg hard rubber roller. , with a free end of the tape that extends beyond the plate, and the adhesive contact area that is 1.27 cm by 2.54 cm. After 30 minutes, the plate is placed either at room temperature or in an oven at 70 ° C and placed 2 degrees from the vertical to prevent detachment. After 10 minutes, the samples at room temperature have a mass of 1000 grams suspended from the free end, and the samples at 70 ° C have either a suspended mass of 500 g or 1000 g from the free end, and the -test at room temperature and at 70 ° C. The time in which the mass falls is recorded. The test is discontinued if the tape has not dropped after 10,000 minutes.

MOLECULAR WEIGHT AND POLIDISPERS ION The weight average molecular weight (MW) and polydispersity (P) of the polymer (before hot melt coating and crosslinking) are determined according to the test procedure described for the Type I test compositions.

Examples-Type II compositions GLOSSARY IOA isooctyl acrylate AA acrylic acid KB-1 2,2-dimethoxy-l, 2-diphenyl-1-ethanone (available from Sartomer Co. Under the trade designation "Escacure KB-1") CBr4 carbon tetrabromide BBP 1, 5-bis (4-benzoylbenzoxy) pentane ABP acryloxybenzophenone BP benzophenone IOTG - isooctylthioglycolate VP CH2 = CH-CONH-C (CH3) 2-COOCH2CH20-FENIL-COC (CH3) 20H SP553 - phenylene terpene resin (available from Schenectady International, Inc.) EXAMPLES 34-36 These examples describe the preparation of a hot melt adhesive composition, wherein the amount and type of the chain transfer agent are varied. The examples were prepared according to the following preparation, general. A partially polymerized pre-adhesive composition was prepared by mixing 30 parts of IOA, 10 parts of AA, 0.15% of KB-1, and all of the chain transfer agent (Example 34) or part of the transfer agent. of chain (Examples 35 and 36). The mixture was placed in a vessel and stirred while nitrogen gas was bubbled through the mixture to exclude oxygen. The mixture was irradiated with low intensity ultraviolet light until a viscous, partially polymerized pre-adhesive composition was obtained. To the partially polymerized pre-adhesive composition, 0.35% KB-1, 0.10% ABP, and the rest of the chain transfer agent were added.

(Examples 35 and 36) and the composition was stirred to ensure complete mixing of the components. The composition was covered by a blade to a thickness of approximately 2.5 mm in thickness (100 mils) between two sheets of polyester transparent to ultraviolet light, 0.05 mm thick -__ (2 mils) coated with a layer of silicone release. The coated sandwich was passed through two irradiation zones, where a total of 750 millij ul / cm2 of energy was spent. Zone 1 was approximately 112.5 milij / cm2 of energy at a luminous intensity of 0.8 milliwatts / cm2. Zone 2 was at an energy of approximately 637.5 milij / cm2 at a luminous intensity of 2.0 milliwatts / cm2. During the irradiation, the coated sandwich was cooled by air shock to remove the polymerization heat. After passing through the two exposure zones, the polyester sheets were removed from the sandwich, the composition was placed in a hot melt coater / extruder, and heated to approximately 177 ° C. The molten composition was then coated to a thickness of approximately 0.05 mm (2 mils) on a release liner coated with silicone. The side / surface without the liner was exposed to medium pressure mercury arc lamps and the hot melt adhesive composition was crosslinked. The tape samples were prepared and tested according to the previous test methods for Adhesion to Detachment and Cutting. The chain transfer agents (CTA) and their amounts used, the post-entitlement energy, adhesion to detachment and cutting, are given in Table 6 below.

TABLE 6 EXAMPLES 37-40 These examples describe the preparation of the hot melt adhesive compositions, wherein the amount and type of crosslinking agents were varied. The samples were prepared as in Example 34, using a total amount of CBr4 of 0.025% by weight as the CTA component added to the monomers, with the exception that a total amount of 0.50% KB-1 in 1 portion was added to the monomers.

The coated samples were evaluated for adhesion to shedding and shearing, according to the test methods described above. The crosslinking agents (CLA) and their amounts used, the energy after crosslinking, adhesion to shearing and shedding, are given in Table 7 below. cuts of 100 grams EXAMPLES 41-44 These examples describe the preparation of the hot melt adhesive compositions, in Where the amounts of cross-linking agents and chain transfer agent were varied.

The samples were prepared according to Examples 37- "40 using various amounts of CBrr and ABP.The coated samples were evaluated for adhesion to shedding and shearing, according to the test methods described hereinabove. of the chain transfer agent (CBr4) and the crosslinking agent (ABP) used, the post¬ energy Crosslinking, adhesion to Peeling and Cutting are given in Table 8 below.

TABLE 8 EXAMPLES 45-46 These examples describe the preparation of the ribbon samples from a composition containing a thickener. The hot melt adhesive composition was prepared according to Examples 34-36 using a total amount of CBr4 of 0.025% by weight as the CTA component, added as in Example 34 to the monomer, and 96 parts of IOA and 4 parts of AA instead of 90 parts of IOA and 10 parts of AA. The thickener was added to the extruder together with the hot melt adhesive composition. 100 millijoules of energy per cm2 were used to post-cross-link the coated composition. Example 45 did not contain thickener (SP553) and Example 46 contained 20% by weight of thickener (SP553) based on 100 parts of adhesive composition. The coated samples were evaluated for adhesion to Peel and Cut according to the test methods described hereinabove. Adhesion to Detachment and Cutting are given in Table 9 below. cuts of 500 g.

EXAMPLES 47-49 These examples describe the preparation and testing of the tape samples that characterize a hot melt adhesive composition with and without a packaging material that is hot melt coatable. The hot melt adhesive composition was prepared as described in Example 35, except that 0.125% ABP was used, the post-crosslinking energy was 200 mJ for Examples 47-48 and 150 mJ for Example 49 , and before the composition was placed in a hot melt extruder, a hot melt hot-melt packaging film (ethylene acrylic acid containing about 9% AA commercially available as PL-50 from Consolidated Thermoplastics Company, Schaumburg, Illinois) of 0.05 mm thickness was laminated to the coated composition for Examples 47 and 49. Example 48 did not have a packaging or lamination film laminated thereto. The tape samples were prepared and tested according to the test methods for Adhesion to Release and Cut and the results are given in Table 10 below.

TABLE 10 These examples show that the composition containing the coating material in molten form (Example 47) has adhesion to peel and cut comparable to the composition that does not contain the packaging material (Example 48). Example 49 shows that at other post-crosslinking energies, the composition containing the hot-melt hot-melt packaging material retains desirable peel adhesion and shear.

EXAMPLES 50-57 These examples describe the preparation of a hot melt adhesive composition, wherein the amounts of the chain transfer agent, the crosslinker and the photoinitiator were varied. These examples were prepared according to the following general preparation. A partially polymerized pre-adhesive composition was prepared by mixing 90 parts of IOA, 10 parts of AA, photoinitiator (KB-1), and a medium of the amount of the chain transfer agent.

(IOTG). The composition was placed in a container and stirred while nitrogen gas was bubbled through the mixture, to exclude oxygen. The mixture was irradiated with low intensity ultraviolet light until a partially polymerized pre-adhesive viscous composition was obtained. To the partially polymerized pre-adhesive composition, the crosslinker (BBP), and the rest of the chain transfer agent (IOTG) were added, and the composition was stirred to ensure complete mixing of the components. The composition was knife-coated to a thickness of approximately 2.5 mm (100 mils) between two sheets of ultraviolet light-transparent polyester of 0.05 mm thickness (2 mils) coated with a silicone release layer The coated sandwich was passed through two irradiation zones, where a total of 750 milij / cm2 of energy was spent, Zone 1 was approximately 112.5 milij / cm2 of energy, at a luminous intensity of 0.8 milliwatts Zone 2 was an area of approximately 637.5 millij ul / cm2 of energy at 2.0 milliwatts / cm2 During the irradiation, the coated walled was cooled by air shock to remove the heat of polymerization. of the two exposure zones, the polyester sheets were removed from the sandwich, the composition was placed in a hot melt coater / extruder and heated to approximately 177 ° C. The melted composition was then coated to a thickness of approximately 0.05 mm (2 mils) on a release liner coated with silicone. The unlined side was exposed to medium pressure mercury atheist lamps and the composition reticulated. The tape samples were prepared and tested according to the previous test methods for Adhesion to Detachment and Cutting. The amounts of photoinitiator, chain transfer agent and crosslinker used; the post-crosslinking energy; Adhesion to Detachment and Cutting are given in the10 Table 11 below.

EXAMPLE 58 This example describes the preparation of a hot melt adhesive composition in which the crosslinker was varied. The example was prepared as Example 50, except that the crosslinker used was ABP and the amount of post-crosslinking energy used was 350 mJ. The tape sample was prepared and tested according to the previous test methods for Adhesion to Detachment and Cutting. Adhesion to Cutting at 70 ° C was measured at 10,000 minutes and Adhesion to Detachment was determined as 36 N / dm.

EXAMPLE 59 This example describes the preparation of a hot melt adhesive composition with high levels of photoinitiator, chain transfer agent, and crosslinker. The example was prepared according to the procedure described in Examples 50-57. The compositions of Examples 50 and 56 were again prepared and tested together with Example 59. The tape sample was prepared and tested according to the test methods described above for Adhesion to Cutting, Molecular Weight, and Polydispersion. The amounts of photoinitiator, chain transfer agent, and crosslinker used; the post-crosslinking energy; adhesion to cutting, molecular weight, and polydispersity are given in Table 12 below. 10 TABLE 12 EXAMPLES 60-68 These examples describe the preparation of a hot melt adhesive composition, wherein the coating thickness of the adhesive and the amount of the post-crosslinking energy were varied. The examples were prepared according to the procedure described in Example 34, except that the amount of the chain transfer agent used was 0.05%, the amount of photoinitiator used was 0.2%, and the total amount of photoinitiator was added in one I only pass on the monomers. The coated thickness of Examples 60-61 was 0.051 mm (0.002 inches); the coated thickness of Examples 64-66 was 0.127 mm (0.005 inches), and the coated thicknesses of the Examples 67-68 was 0.254 mm (0.010 inches). The tape samples were prepared and tested according to the previous test methods for Adhesion to Detachment and Cutting. The post-crosslinking energy and adhesion to shedding and shearing are given in Table 13 below.

TABLE 13 cuts of 500 g From the data it can be seen that as the thickness of the adhesive increases, the adhesion to the release also increases and the adhesion to the cut varies. From the data it can also be observed that for a coating thickness of 0.051 mm, it is preferred to use at least 300 mJ of post-crosslinking energy to achieve high values of adhesion to the cut.

It will be apparent to those of skill in the art that various modifications and variations in the method and article of the present invention may be made, without departing from the spirit or scope of the invention.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention.

Having described the invention as above, property is claimed as contained in the following:

Claims (18)

1. A method for the formation of a hot melt adhesive composition, characterized in that the method comprises the steps of: a) placing on the surface of a sheet, a pre-adhesive composition that after exposure to transmissive energy is polymerizes to form a hot melt adhesive composition; b) exposing said pre-adhesive composition to the transmissive energy, to polymerize the pre-adhesive composition, to form a hot melt adhesive composition; c) removal of the sheet from the hot melt adhesive composition; and d) melting said hot melt adhesive composition.

2. A method according to claim 1, characterized in that it comprises placing the pre-adhesive composition between a pair of sheets, and removing both sheets before melting the hot melt adhesive composition.

3. A method according to claim 1, characterized in that it comprises placing the pre-adhesive composition on the surface of a flexible thermoplastic sheet.

4. A method according to claim 1, characterized in that it comprises placing the pre-adhesive composition between a pair of flexible thermoplastic sheets, and removing both sheets before melting the hot melt adhesive composition.

5. A method according to claim 1, further characterized by comprising placing the melt hot melt adhesive composition on the surface of a sheet to form a sheet coated with hot melt adhesive, and exposing said coated sheet with the hot melt adhesive to ultraviolet radiation or ionizing radiation to form a sheet coated with pressure sensitive adhesive.

6. A method according to any of claims 1 to 5, characterized in that the pre-adhesive composition has a viscosity of less than 50,000 centipoise at 25 ° C.

7. A method according to any of claims 1 to 6, characterized in that the pre-adhesive composition has a melting point not higher than 40 ° C.

8. A method according to any of claims 1 to 6, characterized in that the pre-adhesive composition has a melting point not higher than 25 ° C.

9. A method according to any of claims 1 to 6, characterized in that the pre-adhesive composition has a melting point not higher than 0 ° C.

10. A method according to any of claims 1 to 5, characterized in that the pre-adhesive composition is substantially free of solvent.

11. A method according to any of claims 1 to 5, characterized in that the pre-adhesive composition is substantially free of thixotropic agents.

12. A method according to any of claims 1 to 5, characterized in that the pre-adhesive composition comprises: a) 50 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 1 to 20 carbon atoms; b) 0 to 50 parts by weight of a polymerizable component comprising at least one modification monomer, different from the acrylic or methacrylic ester, copolymerizable with the component (a), representing the sum of (a) and (b) up to 100 parts in weigh; c) an effective amount of a polymerization initiator; and d) an effective amount of a chain transfer agent.

13. A method according to claim 12, characterized in that the pre-adhesive composition further comprises a crosslinking agent.

14. A method according to any one of claims 1 to 13, characterized in that it comprises exposing said pre-adhesive composition to ultraviolet radiation to polymerize the pre-adhesive composition, to form a hot melt adhesive composition.

15. A method according to claim 1, characterized in that it comprises laying on the sheet a layer of pre-adhesive composition having a thickness in the range of 1.2 to 8 mm.

16. A method according to claim 1, characterized in that the hot melt adhesive composition has a weight average molecular weight in the range of 100,000 to 1, 500,000.

17. A method according to claim 1, comprising exposing the pre-adhesive composition to ultraviolet radiation, characterized by a first maximum wavelength or intensity to polymerize the pre-adhesive composition, to form a hot melt adhesive composition.; the removal of the sheet from the hot melt adhesive composition; placing the melt hot melt adhesive composition on the surface of a sheet to form a sheet coated with hot melt adhesive; and exposing the hot-melt adhesive coated sheet to ultraviolet radiation, characterized by a second maximum wavelength or intensity different from the first maximum wavelength or intensity, to form a sheet coated with the sensitive adhesive. the pressure.

18. A method according to claim 1, comprising the exposure of the pre-adhesive composition to ultraviolet radiation, characterized by a maximum wavelength in the range of 220 to 400 nanometers and an average light intensity in the range of 0.01 to 20 mW / cm2 to polymerize the pre-adhesive composition, to form a hot melt adhesive composition; the removal of the sheet from the hot melt adhesive composition; melting of the hot melt adhesive composition; placing the melt hot melt adhesive composition on the surface of a sheet to form a sheet coated with the hot melt adhesive; "and exposing the sheet coated with the hot melt adhesive to radiation ultraviolet, characterized by a maximum wavelength of 220 to 400 nanometers and an average luminous intensity in the range of 20 to 200 mW / cm2 to form "a sheet coated with the pressure sensitive adhesive.