Preparation of high molecular weight polymers with minimal gel content

Abstract

Curable precursor compositions for adhesives (e.g., pressure sensitive adhesives), and related articles, assemblies, and methods. The compositions provided contain a mixture including 50-100 parts by weight of a first polymerizable component and 0-50 parts by weight of a second polymerizable component, a transition metal complex that is soluble in the mixture, and an effective amount of a polymerization initiator, thereby enabling the formation of a high molecular weight polymer (i.e., a hot melt processable adhesive) that is essentially gel free and can be readily processed by established hot melt techniques, even in the absence of chain transfer or crosslinking agents.

Description

[Background technology]

[0001] Methods are known for making packaged viscoelastic compositions in which the packaging material is either retained after polymerization (i.e., the first type of product) or removed after polymerization and before subsequent processing (i.e., the second type of product).For example, U.S. Patent No. 5,804,610 (Hamer et al.) discloses and describes these two types of products separately, particularly with respect to hot melt adhesive compositions (also referred to herein as "hot melt processable adhesives"), but the principles described are equally applicable to other types of viscoelastic compositions, such as pressure sensitive adhesives in general, hot melt processable sealants, vibration damping materials, and gels for medical applications. Summary of the Invention

[0002] Provided herein is a composition containing a mixture comprising 50-100 parts by weight of a first polymerizable component and 0-50 parts by weight of a second polymerizable component, a transition metal complex soluble in the mixture, and an effective amount of a polymerization initiator, which allows for the formation of a high molecular weight polymer (i.e., a hot melt processable adhesive) that is essentially gel free, even in the absence of chain transfer agents or crosslinkers, that can be readily processed by established hot melt techniques.

[0003] Methods for preparing the disclosed pre-adhesive compositions, and articles including such pre-adhesive compositions, are also described herein.

[0004] As used herein, "Common solvent" refers to low molecular weight organic liquids commonly used as solvents by those skilled in the art, including aliphatic and alicyclic hydrocarbons (e.g., hexane, heptane, and cyclohexane), aromatic solvents (e.g., benzene, toluene, and xylene), ethers (e.g., diethyl ether, glyme, diglyme, diisopropyl ether, and tetrahydrofuran), esters (e.g., ethyl acetate and butyl acetate), alcohols (e.g., ethanol and isopropyl alcohol), ketones (e.g., acetone, methyl ethyl ketone, and methyl isobutyl ketone), sulfoxides (e.g., dimethyl sulfoxide), amides (e.g., N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone), halogenated solvents (e.g., methyl chloroform, 1,1,2-trichloro-1,2,2-trifluoroethane, trichloroethylene, and trifluorotoluene), and mixtures thereof, with the exception that "common solvent" excludes species that act as monomers or otherwise as reactants in a given composition; Any amount of a material that is "essentially free" in a composition may be replaced with "less than 5 weight percent," "less than 4 weight percent," "less than 3 weight percent," "less than 2 weight percent," "less than 1 weight percent," "less than 0.5 weight percent," "less than 0.1 weight percent," or "none."

[0005] "Expandable polymeric microspheres" refer to microspheres that include a polymer shell and a core material in the form of a gas, liquid, or combination thereof that expands upon heating, the expansion of the core material in turn causing the shell to expand at least at the heating temperature.

[0006] By "hot melt processable adhesive" is meant an adhesive essentially free of common solvents that is capable of being hot melt processed under conventional conditions, which hot melt processing includes hot melt blending and extrusion.

[0007] "Pressure sensitive adhesive" or "PSA" means a material that has at least the following properties: a) a tacky surface, b) the ability to adhere with or without finger pressure, c) the ability to adhere without activation by any energy source, d) sufficient ability to be held on the intended substrate, and preferably e) sufficient cohesive strength to be removed cleanly from the substrate, typically meeting the Dahlquist criterion of having a storage modulus at 1 Hz and room temperature of less than 0.3 MPa.

[0008] By "structural adhesive" is meant an adhesive that bonds by irreversible cure, typically with a strength when bonded to its intended substrate, measured as a break stress (peak stress) of at least 100 psi, in some embodiments at least 200 psi, and in some embodiments at least 300 psi, using an overlap shear test.

[0009] All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified.

[0010] As used in this specification and the appended claims, past tense verbs such as "coated" and "embossed" are intended to describe structures and are not intended to limit the process used to obtain the recited structure, unless otherwise specified.

[0011] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include embodiments having plural referents unless the content clearly dictates otherwise.

[0012] As used in this specification and the appended claims, the term "or" is generally used in its sense including "and / or" unless the content clearly indicates otherwise.

[0013] As used herein, the words "have," "having," "include," "including," "comprise," "comprising," and the like are used in an open-ended sense and generally mean "including, but not limited to." It is understood that the terms "consisting of" and "consisting essentially of" are encompassed by terms such as "comprising."

[0014] The features and advantages of the present disclosure will be further understood by consideration of the detailed description and the appended claims. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] It is known that the use of chain transfer agents and crosslinkers prepares packaged viscoelastic compositions with moderate molecular weight, suitable cohesive strength, and minimal gel content (e.g., less than 5% by weight) and uses them in adhesives to balance material performance with processing conditions.However, when high molecular weight polymers (i.e., polymers with Mz greater than about 2,000,000) are produced according to these known methods, higher gel content may be observed, which may result in processing difficulties or unacceptable coating appearance.In some cases, especially in pressure-sensitive adhesive ("PSA") applications, these higher molecular weight polymers are required, so these applications have been forced to rely on solvent-made polymers instead of hot-melt processable adhesives to achieve the higher molecular weight range required in combination with lower gel content.

[0016] As demonstrated in this disclosure, it has surprisingly been found that when a transition metal complex (e.g., a copper(II) salt) that is soluble in the monomer mixture of the pre-adhesive composition is present during the preparation of the packaged viscoelastic composition, it is possible to form a high molecular weight polymer (i.e., a hot melt processable adhesive) that is essentially gel free, which can be readily processed via established hot melt techniques, even in the absence of chain transfer agents or crosslinkers.

[0017] In one aspect, provided herein is a pre-adhesive composition that includes a mixture including a first polymerizable component and optionally a second polymerizable component, a transition metal complex that is soluble in the mixture, and an effective amount of a polymerization initiator.

[0018] First Polymerizable Component In preferred embodiments of the present disclosure, the pre-adhesive composition comprises a mixture comprising 50-100 parts by weight, 70-100 parts by weight, 90-100 parts by weight, or 100 parts by weight of a first polymerizable component. The first polymerizable component comprises a (meth)acrylic acid ester of a non-tertiary alkyl alcohol, where the alkyl group comprises 1-20 carbon atoms, optionally 1-18 carbon atoms, optionally 1-16 carbon atoms, optionally 1-14 carbon atoms, optionally 1-12 carbon atoms, optionally 1-10 carbon atoms, or optionally 1-8 carbon atoms. In some embodiments, the first polymerizable component comprises an aromatic acrylate, such as, for example, benzyl acrylate and cyclobenzyl acrylate. In some preferred embodiments, the first polymerizable component is selected from the group consisting of primary alkyl (meth)acrylates, secondary alkyl (meth)acrylates, and combinations thereof. Useful primary and secondary alkyl (meth)acrylates include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobornyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, cyclohexyl acrylate, iso-octyl acrylate, octadecyl acrylate, nonyl acrylate, decyl acrylate, isobornyl acrylate, dodecyl acrylate, 2-methyl-3-phenylpropanediol ... 2-propylheptyl acrylate, heptadecanyl acrylate, 2-butyl-1-octyl acrylate made according to Example GM1 of U.S. Pat. No. 8,137,807 (Clapper et al.), a C18 acrylate isomer blend made according to Example GM4 of U.S. Pat. No. 8,137,807 (Clapper et al.), as well as an alkyl acrylate isomer blend prepared as described in U.S. Pat. No. 9,102,774 (Clapper et al.).

[0019] Second Polymerizable Component In some embodiments of the present disclosure, the pre-adhesive composition may comprise a mixture including up to 50 parts by weight, up to 30 parts by weight, up to 10 parts by weight of a second polymerizable component having at least one modifying monomer copolymerizable with the first polymerizable component other than the methacrylic acid esters described above, the total of the first polymerizable component and the second polymerizable component being 100 parts by weight. Representative examples of non-acidic functional polar monomers suitable for use as the polymerizable component of the second polymerizable component include, but are not limited to, 2-hydroxyethyl (meth)acrylate, N-vinylpyrrolidone, N-vinylcaprolactam, acrylamide, mono- or di-N-alkyl substituted acrylamide, t-butylacrylamide, dimethylaminoethylacrylamide, N-octylacrylamide, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxyethoxyethyl (meth)acrylate, 2-methoxyethyl methacrylate, poly(alkoxyalkyl) (meth)acrylates such as polyethylene glycol mono(meth)acrylate, alkyl vinyl ethers such as vinyl methyl ether, and mixtures thereof. Preferred polar monomers include those selected from the group consisting of 2-hydroxyethyl (meth)acrylate and N-vinylpyrrolidone. In some embodiments, the second polymerizable component may include an acid functional monomer, and the acid functional group may be the acid itself, such as a carboxylic acid, or a portion may be a salt thereof, such as an alkali metal carboxylate. Useful acid functional monomers include, but are not limited to, those selected from ethylenically unsaturated carboxylic acids, ethylenically unsaturated sulfonic acids, ethylenically unsaturated phosphonic acids, and mixtures thereof. Examples of such compounds include those selected from acrylic acid, methacrylic acid, itaconic acid, fumaric acid, crotonic acid, citraconic acid, maleic acid, oleic acid, β-carboxyethyl (meth)acrylate, 2-sulfoethyl methacrylate, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, vinyl phosphonic acid, and mixtures thereof.Due to availability, the acid functional monomer of the acid functional copolymer is generally selected from ethylenically unsaturated carboxylic acids, i.e. (meth)acrylic acid. If even stronger acids are desired, acidic monomers include ethylenically unsaturated sulfonic acids and ethylenically unsaturated phosphonic acids. In some preferred embodiments, the second polymerizable component is selected from the group consisting of acrylic acid, N-vinylpyrrolidone, and combinations thereof.

[0020] Transition metal complexes Transition metal complexes useful in embodiments of the present disclosure include those that are soluble in the mixture of the first and second polymerizable components described above. In some preferred embodiments, the transition metal complex comprises copper. In some preferred embodiments, the transition metal complex is selected from the group consisting of copper(II) 2-ethylhexanoate, copper(II) acetate, copper(II) acetylacetonate, copper(II) trifluoroacetate, and combinations thereof. The pre-adhesive composition of the present disclosure typically comprises 0.01% to 0.2% by weight, optionally 0.02% to 0.12% by weight of the transition metal complex, in parts by weight based on the total weight of the mixture including the first polymerizable component and, if present, the second polymerizable component.

[0021] Polymerization initiator Polymerization initiators useful in embodiments of the present disclosure are known in the art and include Norrish Type I photoinitiators, such as those available under the trade name OMNIRAD from IGM Resins (Waalwijk, The Netherlands). Suitable photoinitiators include, for example, 2,2-dimethoxy-1,2-diphenylethan-1-one (OMNIRAD 651), 2-hydroxy-2-methyl-1-phenylpropan-1-one (OMNIRAD 1173), 1-hydroxycyclohexylphenyl-ketone (ONNIRAD 184), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (OMNIRAD TPO), and 2,4,6-trimethylbenzoylphenylphosphinate (OMNIRAD TPO-L).

[0022] The photoinitiator is typically present in the pre-adhesive composition in an amount of up to about 1 wt%, based on the total weight of the first polymerizable component and the second polymerizable component, if present. In some cases, the photoinitiator is present in an amount of 0.05 wt% or more, 0.07 wt% or more, or 0.1 wt% or more; and 1 wt% or less, 0.8 wt% or less, or 0.6 wt% or less. In other words, the photoinitiator can be present in an amount of about 0.05 wt% to 1 wt%, 0.07 wt% to 0.8 wt%, or 0.1 wt% to 0.6 wt%, based on the total weight of the polymerizable components of the first polymerizable component and the second polymerizable component, if present.

[0023] Pre-adhesive composition additives Various other optional ingredients well known to those skilled in the art can be added to the pre-adhesive composition, such as tackifiers, plasticizers, antioxidants, and combinations thereof. Tackifiers useful in embodiments of the present disclosure are known in the art and can include, for example, ARKON P-125 hydrocarbon resin available from Arakawa Europe GnbH (Germany), CLEARON P150 available from Yasuhara Chemical, and ENDEX 160 available from Eastman Chemical Company, Kingsport, Tennessee. The plasticizer is preferably non-volatile and non-reactive. Particularly useful plasticizers include, for example, CARBOWAX 750, an acrylate-functional derivative of methoxypolyethylene oxide available from Dow Chemical Co., Midland, MI, and PLURONIC 25R4, an ethylene oxide / propylene oxide block copolymer plasticizer available from BASF Company, Ludwigshafen, Germany. Antioxidants can be used to protect against harsh environmental aging caused by ultraviolet light or heat.Antioxidants include, for example, hindered phenols, amines, and sulfur, and phosphorus hydroxide decomposers.Preferred antioxidants include, for example, IRGANOX 1076 and IRGANOX 1010, available from BASF, Ludwigshafen, Germany.The amount of each additive generally varies depending on the intended use of the resulting composition.

[0024] Goods The pre-adhesive compositions of the present disclosure may be prepared and processed by methods known to those skilled in the art and as described in the Examples below. Polymerized materials comprising the disclosed pre-adhesive compositions can be made, for example, by blending a first polymerizable component, optionally a second polymerizable component, a transition metal complex that is soluble in the mixture, and a polymerization initiator in a suitable reaction vessel, followed by exposing the pre-adhesive composition contained in a sealed film receptacle to ultraviolet ("UV") radiation. In some preferred embodiments, irradiation can result in greater than 99% conversion of the first and second polymerizable components to polymerized material. In some preferred embodiments, the polymerized material is greater than 95% soluble, greater than 96% soluble, greater than 97% soluble, or greater than 98% soluble in ethyl acetate. In some preferred embodiments, the polymerized material has an Mz of 2,000,000 to 4,000,000. In some preferred embodiments, the polymerized material has an intrinsic viscosity of 1.2 to 2.3.

[0025] Depending on the desired properties of the final product, other additives may also be included in the polymerized material, such as, for example, crosslinkers (e.g., 1,6-hexanediol acrylate), chain transfer agents (e.g., alkenes, alcohols), tackifiers, plasticizers, expandable polymeric microspheres, and combinations thereof. In some embodiments, the crosslinkers react under UV light. In some embodiments, the crosslinkers react under electron beam irradiation. In some embodiments, the chain transfer agents do not contain thiol functional groups. In some embodiments, the chain transfer agents include secondary alcohols. In some embodiments, the chain transfer agents include unsaturated hydrocarbons. Useful examples of tackifying resins suitable for embodiments of the present disclosure include, but are not limited to, liquid rubbers, aliphatic and aromatic hydrocarbon resins, natural resins such as rosins, dimerized or hydrogenated balsams and esterified abietic acid, polyterpenes, terpene phenolic resins, phenol-formaldehyde resins, and rosin esters. Useful examples of plasticizers include, but are not limited to, polybutene, paraffin oil, naphthenic oil, petrolatum, and certain phthalates with long aliphatic side chains, such as ditridecyl phthalate. In some embodiments, the plasticizer does not contain acrylate functionality. Expandable polymeric microspheres useful in embodiments of the present disclosure include those described in U.S. Pat. No. 7,879,441 (Gehlen et al.).

[0026] In some embodiments, the polymerized material is a component of an adhesive, such as, for example, a pressure sensitive adhesive, a structural adhesive, or a hot melt adhesive. An article is provided that includes such an adhesive composition and a substrate. In some embodiments, a layer of the adhesive composition is disposed adjacent to the substrate. The adhesive composition may be in direct contact with the substrate or may be separated from the substrate by one of more layers, such as a primer layer.

[0027] Any suitable substrate can be used. In some articles, the substrate is flexible. Examples of flexible substrate materials include, but are not limited to, polymeric films, woven or nonwoven fabrics; metal foils, foams (e.g., polyacrylic, polyethylene, polyurethane), and combinations thereof (e.g., metallized polymeric films). Polymeric films include, for example, polypropylene (e.g., biaxially oriented), polyethylene (e.g., high density or low density), polyvinyl chloride, polyurethane (e.g., thermoplastic polyurethane), polyester (e.g., polyethylene terephthalate ("PET"), polyethylene naphthalate ("PEN"), and polylactic acid copolymers), polycarbonate, polyacrylate, polymethyl(meth)acrylate ("PMMA"), polyvinyl butyral, polyimide, polyamide, fluoropolymer, cellulose acetate, triacetyl cellulose (TAC), ethyl cellulose, and polycyclic olefin polymers ("COP"). Woven or nonwoven fabrics may include fibers or filaments of synthetic or natural materials, such as cellulose, cotton, nylon, rayon, glass, and ceramic.

[0028] In some embodiments, the article is or comprises an adhesive tape. Examples of such adhesive tapes include transfer tapes, single-sided adhesive tapes, double-sided tapes with an adhesive layer on each side of the substrate (i.e., a core substrate such as, for example, foam), or die-cut adhesive articles (e.g., the article has an adhesive layer adjacent to a release liner or between two release liners). Such adhesive tapes may include a wide variety of substrates for use as backings or release liners. Examples include woven and nonwoven materials, plastic films, metal foils, and the like.

[0029] Adhesive tapes are often prepared by coating adhesive compositions onto various flexible or inflexible backing materials and / or release liners using conventional coating techniques to produce single-sided or double-sided tapes. For single-sided adhesive tapes, the adhesive composition can be coated onto a layer of backing material, and the side of the backing material opposite to where the adhesive is placed can be coated with a suitable release material (e.g., a release layer or release liner). Release materials are known and include, for example, silicone, polyethylene, polycarbamate, polyacrylic, and other materials. For double-sided adhesive tapes, a first adhesive composition is coated onto a layer of backing material, and a second layer of adhesive composition is placed on the opposite surface of the backing material. The second layer may comprise an adhesive composition described herein or a different adhesive composition. For die-cut adhesive articles or transfer tapes, the adhesive composition is typically placed between two release liners. The adhesive article can also be part of another article. For example, the adhesive composition can bond two parts of an article together.

[0030] Objects and advantages of the present disclosure are further illustrated by the following non-limiting examples, but the specific materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit the disclosure. EXAMPLES

[0031] Unless otherwise stated or readily apparent from the context, all parts, percentages, ratios, etc. in the examples and elsewhere in the specification are by weight. [Table 1]

[0032] Preparation of "100% Solids" or "Bulk" Polymers Used in the Examples The monomer mixture was prepared by blending reactive acrylic monomer, photoinitiator, antioxidant, and copper (II) salt in a jar. A magnetic stir bar was added to the mixture and the mixture was placed on a stir plate to form the curable composition. The EVA film was heat sealed to form open-ended receptacles, each 18 cm by 5 cm. Each receptacle was filled with approximately 24 grams of the curable composition. Air was removed from the open end, and the open end was then sealed using a heat sealer (obtained under the trade designation "MIDWEST PACIFIC IMPULSE SEALER" from JJ Elemer Corp., St. Louis, MO). The sealed EVA film receptacles with the curable composition enclosed inside were immersed in a water bath at a constant temperature of 16° C. and exposed to ultraviolet light (365 nm, 4 mW / cm 2 ). 2 ) for 9 minutes on each side to polymerize the curable composition. The polymerized samples were removed from the EVA film receptacle for testing as described below.

[0033] Test Method Test method 1: Gel content measurement Approximately 24 g of rectangular polymer sample was placed in the center of a pre-weighed rectangular mesh. The mesh was stainless steel type 304 weave wire cloth (obtained under the trade designation "MCMASTER-CARR" from McMaster-Carr Co., Elmhurst, IL) with a 150 mesh weave construction using 0.0026 inch (66 micrometer) wires and 0.0041 inch (104 micrometer) openings. The protruding parts of the mesh were folded inwards, encasing and immobilizing the sample inside the mesh. The folded mesh with encapsulated polymer was weighed and then immersed in approximately 8 ounces (approximately 240 ml) of ethyl acetate for 24 hours in a glass jar placed on a mechanical roller. The mesh with polymer was then removed from the jar, dried in an oven for 30 minutes at 120° C., reweighed, and the mass of the sample was calculated. The gelled, insoluble portion of the polymer was calculated as gel weight percent ("Gel Wt %") using the following formula:

number

[0034] Test Method 2: Determination of Percent Solids Dry samples were prepared by weighing a sample of the test material (0.5 g to 2.0 g), placing it in a small open aluminum container, and maintaining it overnight in a convection oven (obtained under the trade designation "SYMPHONY" from VWR Corporation, Radnor, PA) at approximately 105° C. The weight of the dry sample was measured and recorded. The amount of monomer converted to polymer was calculated by measuring the weight loss of the evaporated monomer and expressed as weight percent (wt %).

[0035] Test Method 3: Intrinsic Viscosity ("IV") Measurement The intrinsic viscosity (IV) reported herein was obtained by conventional methods known to those skilled in the art. IV was obtained using a single-bath dilute solution polymer viscometer (obtained under the trade designation "MINIPV-X" from Cannon Instrument Co., State College, PA) in a water bath controlled at 27°C to measure the flow time of 10 mL of polymer solution (0.3 g / dL of polymer in ethyl acetate). The test procedures followed and the equipment used are described in detail in Textbook of Polymer Science, FW Billmeyer, Wiley-Interscience, Second Edition, 1971, Pages 84 and 85.

[0036] Test method 4: GPC analysis Approximately 50 mg of polymer solids were placed in 10 mL of THF (stabilized with 250 ppm BHT). The samples were mixed at low speed on a mechanical shaker (obtained from Eberbach Corporation, Belleville, MI under the trade designation E6010.00) for approximately 3 hours to prepare the polymer solutions. All polymer solutions were passed through a 0.45 micron syringe filter and analyzed by gel permeation chromatography ("GPC"). The GPC consists of a pump, column, and detector. The column and detector are described below. The pump was obtained from Agilent Technologies, Santa Clara, CA under the trade designation "AGILENT 1100 HPLC". Samples were prepared and analyzed in duplicate, and the average of the two values ​​was reported.

[0037] GPC equipment and conditions: Sample: Stabilized with tetrahydrofuran Samples were filtered through a 0.45 micron membrane at 5mg / mL, and 50μL was injected. Mobile phase: stabilized UV-grade tetrahydrofuran (obtained under the trade name "EMD OMNISOLV" from MilliporeSigma Co., Burlington, Mass.); or equivalent grade tetrahydrofuran Flow rate: 1.0mL / min Detector: Refractive index detector (obtained under the trade name "1200 SERIES G1362" from Agilent Technologies, Santa Clara, CA) Column: Nominal MW range 500~10 7 Two of the columns are 7.8 mm x 300 mm in diameter and 100 mm in diameter (obtained under the trade designation "PLGEL 10 MICRON MIXED-B" from Agilent Technologies, Santa Clara, CA), and one with a nominal MW range of 200-400,000 Daltons (obtained under the trade designation "PLGEL 5 MICRON MIXED-D" from Agilent Technologies). All columns are 7.8 mm x 300 mm. The columns are maintained at 40°C. Standard: Polystyrene, narrow dispersity; 6.035×10 6~580 Mp range; (3rd order polynomial fit) available from Agilent, Santa Clara, CA under the trade name "EASICAL PS-1" Syringe Filter Type: 0.45 micron PTFE Abbreviation: Mw=weight average molecular weight Mn=number average molecular weight Mz=Z average molecular weight Polydispersity = Mw / Mn, a number relating to the width of the distribution curve

[0038] Comparative Example CE1 and Examples 2-6: Preparation and Analysis of High Molecular Weight Polymers with Minimal Gel Content For each Example / Comparative Example, the general procedure for "Preparation of 100% Solids" or "Bulk" Polymer was followed and the amounts listed in Table 1 (parts by weight based on the total weight of isomer mixtures A and AA) were used to provide a Comparative Example (CE-1) and five Examples (Ex. 2-6). [Table 2]

[0039] GPC analysis was carried out on CE-1 and each of Examples 2 to 6. The results are summarized in Table 2. [Table 3]

[0040] Gel content and intrinsic viscosity ("IV") measurements were performed on CE-1 and each of Examples 2-6. The results are summarized in Table 3. [Table 4]

[0041] Examples 7-10: Preparation and Analysis of High Molecular Weight Polymers with Minimal Gel Content and Intrinsic Viscosity Greater than 1.8 The examples were made according to the general procedure for "Preparation of '100% Solids' or 'Bulk' Polymer," except that the starting materials and their amounts (parts by weight based on the total weight of IOA, MA, and AA) were as shown in Table 4. [Table 5]

[0042] Gel content and intrinsic viscosity ("IV") measurements were performed on each of Examples 7-10. The results are summarized in Table 5. [Table 6]

[0043] Examples 11-12: Preparation and analysis of high molecular weight polymers containing IOA with minimal gel content The examples were made according to the general procedure for "Preparation of '100% Solids' or 'Bulk' Polymer," except that the amounts of materials (parts by weight based on the total weight of IOA and AA) were as shown in Table 6. [Table 7]

[0044] Gel content and intrinsic viscosity ("IV") measurements were performed on each of Examples 7-10. The results are summarized in Table 7. [Table 8]

[0045] Examples 13-16: Preparation and analysis of high molecular weight polymers with minimal gel content made using various Cu(II) sources The examples were made according to the general procedure for "Preparation of '100% Solids' or 'Bulk' Polymer", except that the amounts of materials (parts by weight based on the total weight of ISOMER MIX A and AA) were as shown in Table 8. [Table 9]

[0046] Gel content and intrinsic viscosity ("IV") measurements were performed on each of Examples 13-16. The results are summarized in Table 9. [Table 10]

[0047] Examples 17-22: Preparation and Analysis of UV-Cured High Molecular Weight Polymers The examples were made according to the general procedure for "Preparation of '100% Solids' or 'Bulk' Polymer", except that the amounts of materials (parts by weight based on the total weight of Isomer Mixture A and AA) were as shown in Table 10. [Table 11]

[0048] UV curing of materials in the presence and absence of Cu(2-ethylhexanoate) was tested. Samples of materials from Table 10 were compounded in a twin screw extruder at 160°C for 3 minutes. The resulting hot melt was coated onto a silicone release liner using a drop die. The die and extruder extrusion temperature were maintained at 160°C. The extruded samples were coated at a thickness of 3 mils (76 micrometers). The samples were then laminated onto a PET film (obtained under the trade designation "HOSTAPHAN 3SAB" from Mitsubishi Polyester Film, Inc., Greer, SC) and cured at multiple UV-C doses using a UV melt lamp and H bulb as shown in Table 11. Gel content measurements were made for each of Examples 17-22 cured with a given UV-C radiation. The gel weight % was measured and the results are summarized in Table 11. [Table 12]

[0049] Examples 23-26: Preparation and Analysis of Electron Beam Cured High Molecular Weight Polymers The examples were made according to the general procedure for "Preparation of '100% Solids' or 'Bulk' Polymer," except that the amounts of materials (parts by weight based on the total weight of IOA, MA, and AA) were as shown in Table 12. [Table 13]

[0050] The materials were tested for electron beam curing. Samples of the materials from Table 12 were compounded in a twin screw extruder at 160°C. The resulting hot melt was coated onto a silicone release liner using a drop die. The extrusion temperature of the die and extruder was maintained at 160°C. The extruded samples were coated at a thickness of 3 mils (about 76 micrometers). The samples were then laminated onto a PET film (obtained under the trade designation "HOSTAPHAN 3SAB" from Mitsubishi Polyester Film, Inc., Greer, SC) and cured at various electron beam doses using an electron beam generator. Gel content measurements were performed for each of Examples 23-26. The results of electron beam dose and gel weight % are summarized in Table 13. [Table 14]

[0051] Examples 27-29: Preparation and Analysis of High Molecular Weight Polymers Containing Alkene Chain Transfer Agents The examples were made according to the general procedure for "Preparation of '100% Solids' or 'Bulk' Polymers," except that the amounts of materials (parts by weight based on the total weight of IOA, MA, and AA) were as shown in Table 14 and an unsaturated hydrocarbon was further included in the formulation. [Table 15]

[0052] Gel content and intrinsic viscosity ("IV") measurements were performed on each of Examples 27-29. The results are summarized in Table 15. [Table 16]

[0053] Examples 30-32: Preparation and analysis of high molecular weight polymers containing alcohol chain transfer agents The examples were made according to the general procedure for "Preparation of '100% Solids' or 'Bulk' Polymers", except that the amounts of materials (parts by weight based on the total weight of IOA, MA, and AA) were as shown in Table 16 and alcohol was added as a chain transfer agent. [Table 17]

[0054] Gel content and intrinsic viscosity ("IV") measurements were performed for each of Examples 30-32. The results are summarized in Table 17. [Table 18]

[0055] Examples 33-34: Preparation and Analysis of High Molecular Weight Polymers Containing Tackifiers The examples were made according to the general procedure for "Preparation of '100% Solids' or 'Bulk' Polymers", except that the amounts of materials (parts by weight based on the total weight of ISOMER MIX and AA) were as shown in Table 18 and Arkon P125 was added to the mixture as a tackifier. [Table 19]

[0056] Example 33 was found to polymerize completely even in the presence of both copper salt and tackifier. Gel content and intrinsic viscosity ("IV") measurements were performed on Example 33. The results are summarized in Table 19. [Table 20]

[0057] A portion of Example 34 (100 grams) was compounded with Arkon P-125 (20 grams) in a single screw extruder at 160° C. for 3 minutes. The resulting hot melt was coated onto a silicone release liner using a drop die. The extrusion temperature of the die and extruder was maintained at 160° C. The extruded sample was coated to a thickness of 3 mils (76 micrometers). The material was observed to be homogeneous.

[0058] Examples 35-36: Preparation and analysis of high molecular weight polymers containing plasticizers The examples were made according to the general procedure for "Preparation of '100% Solids' or 'Bulk' Polymers," except that the amounts of materials (parts by weight based on the total weight of Isomer Mixture A and AA, which contain either Pluronic 25R4 or Carbowax 750) were as shown in Table 20. Carbowax 750 was added as the reactive plasticizer and Pluronic 25R4 was added as the functional plasticizer. [Table 21]

[0059] Gel content and IV measurements were performed on each sample, and the IV and gel weight % results are summarized in Table 21. [Table 22]

[0060] A portion of Example 34 (100 grams) was compounded with PLURONIC 25R4 (20 grams) in a single screw extruder at 160° C. for 3 minutes. The resulting hot melt was coated onto a silicone release liner using a drop die. The extrusion temperature of the die and extruder was maintained at 160° C. The extruded sample was coated to a thickness of 3 mils (76 micrometers). The material was observed to be homogeneous.

[0061] Comparative Examples CE-37 to CE-40: Solution polymers prepared in the presence of Cu(II) salts Solution Polymerization Method: To a 250 ml amber bottle were added Isomeric Mixture A, AA, Cu(2-ethylhexanoate), HDDA, and Vazo 67 using the relative amounts (parts by weight based on the total weight of Isomeric Mixture A, AA, and IBOA) shown in Table 22. [Table 23]

[0062] Ethyl acetate (100 g) was added to the bottle, which was sufficient to result in approximately 50% solids after reaction. The contents of the bottle were thoroughly mixed and degassed by bubbling a constant stream of nitrogen gas through the solution for 2 minutes. The bottle was then sealed and polymerized for 24 hours in a water bath set at 65° C. After 24 hours, the bottle was removed and the resulting polymer in solution was analyzed by measuring the percent monomer conversion and IV value. The results are summarized in Table 23. [Table 24]

[0063] All references, patents and patent applications cited in the above patent application for patents are incorporated herein by reference in their entirety in a consistent manner. In the event of any inconsistency or discrepancy between any part of the incorporated reference and any part of this application, the information in the above description shall prevail. The above description is intended to enable a person skilled in the art to practice the disclosure as set forth in the claims, and should not be construed as limiting the scope of the disclosure, which is defined by the claims and all equivalents thereof.

Claims

1. A pre - adhesive composition comprising: (a) 50 to 100 parts by weight of a first polymerizable component, comprising at least one (meth)acrylate ester of a non - tertiary alkyl alcohol, wherein the alkyl group contains 1 to 20 carbon atoms, the first polymerizable component, and (b) 0 to 50 parts by weight of a second polymerizable component, comprising at least one modifying monomer copolymerizable with component (a) other than the (meth)acrylate ester, the second polymerizable component wherein the total of (a)+(b) is 100 parts by weight, a mixture, a transition metal complex soluble in the mixture, and an effective amount of a polymerization initiator, a pre - adhesive composition.

2. The pre - adhesive composition according to claim 1, wherein the first polymerizable component is selected from the group consisting of primary alkyl (meth)acrylate, secondary alkyl (meth)acrylate, and combinations thereof.

3. The pre - adhesive composition according to claim 1, wherein the alkyl group of the first polymerizable component contains 1 to 18 carbon atoms.

4. The pre - adhesive composition according to claim 1, wherein the second polymerizable component is selected from the group consisting of acrylic acid, n - vinylpyrrolidone, and combinations thereof.

5. The pre - adhesive composition according to claim 1, wherein the transition metal complex contains copper.

6. The pre - adhesive composition according to claim 5, wherein the transition metal complex is selected from the group consisting of copper(II) 2 - ethylhexanoate, copper(II) acetate, copper(II) acetylacetonate, copper(II) trifluoroacetate, and combinations thereof.

7. The pre - adhesive composition according to claim 1, wherein the polymerization initiator is a Norrish type I photo - initiator.

8. The pre - adhesive composition according to claim 1, wherein the effective amount of the polymerization initiator is 0.05 wt% to 1 wt% based on the total of (a)+(b).

9. The pre - adhesive composition according to claim 1, further comprising an additive selected from the group consisting of tackifiers, plasticizers, and combinations thereof.

10. A polymerized material comprising the pre - adhesive composition according to claim 1.

11. The polymerized material according to claim 10, wherein the conversion rate of the first polymerizable component and the second polymerizable component to the polymerized material, measured by test method 2, is greater than 99%.

12. The polymerized material according to claim 10, which is measured by Test Method 1 and is more than 95% soluble in ethyl acetate.

13. The polymerized material according to claim 10, which has an Mz of 2,000,000 to 4,000,000 as measured by Test Method 4 and an intrinsic viscosity of 1.2 to 2.3 as measured by Test Method 3.

14. The polymerized material according to claim 10, further comprising an additive selected from the group consisting of a crosslinking agent, a chain transfer agent, a tackifier, a plasticizer, expandable polymer microspheres, and combinations thereof.

15. The polymerized material according to claim 14, wherein the crosslinking agent reacts under UV light.

16. The polymerized material according to claim 14, wherein the crosslinking agent reacts under electron beam irradiation.

17. The polymerized material according to claim 14, wherein the chain transfer agent does not contain a thiol functional group.

18. The polymerized material according to claim 14, wherein the chain transfer agent contains a secondary alcohol.

19. The polymerized material according to claim 14, wherein the chain transfer agent contains an unsaturated hydrocarbon.

20. The polymerized material according to claim 14, wherein the plasticizer does not contain an acrylate functional group.

21. A pressure-sensitive adhesive comprising the polymerized material according to any one of claims 10 to 20.

22. A structural adhesive comprising the polymerized material according to any one of claims 10 to 20.

23. A tape comprising the polymerized material according to any one of claims 10 to 20.