MXPA98004624A - Polymerization in block by radicals using a reactor therefore - Google Patents

Abstract

The present invention provides a method for the polymerization of free radical polymerizable vinyl monomers in a batch reactor under essentially adiabatic conditions

Description

POLYMERIZATION IN BLOCK BY RADICALS USING A BATCH REACTOR DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention provides a method for the polymerization of free radical polymerizable vinyl monomers in a batch reactor.

BACKGROUND OF THE INVENTION Bulk (ie massive) free-radical polymerization of pure monomer typically involves a high-heat (i.e. highly exothermic) reaction, which increases the viscosity of the solution as the polymerization progresses and the corresponding decrease in the heat transfer coefficient of the reactive material. Due to these problems, controlling the temperature of the block polymerization process can be extremely difficult. However, it is well known to those skilled in the art that maintaining the desired temperature is very important due to the strong dependence of the reaction kinetics by free radicals of the reaction temperature, which directly affects the properties of the polymer such as the molecular weight distribution and molecular weight. If the heat released from the reaction exceeds the heat removal capacity due to the decrease in heat transfer, an uncontrolled escape may result where the reaction rate increases as the temperature rises due to the reaction Exothermic To avoid these problems, free radical polymerization is commonly carried out in solution, where a non-reactive solvent is used in which the monomer and the polymer are both soluble to reduce the heat load, as well as to increase the transfer coefficient of heat from the reaction mixture to facilitate temperature control. Alternatively, the heat load and viscosity / heat transfer problems are commonly handled by suspension polymerization and emulsion polymerization methods. The methods of solution polymerization, suspension polymerization and emulsion polymerization are disadvantageous since they require extra equipment and extra processing. Polymerization in solution, suspension and emulsion provides a lower yield on block polymerization for a specific reactor volume. The emulsion and suspension polymerization offer the possibility of introducing contaminants into the polymer of the surfactants and / or emulsifiers used in the polymerization process. Contaminants can also be introduced through impurities in the solvent in the solution polymerization. In addition, in the case of solution polymerization, solvent handling can be dangerous due to the danger of fire and / or explosion. Solvent handling can be expensive because extra equipment may be necessary to capture the solvent for reuse or another capture method, such as thermal oxidizers, may be required to prevent the compounds from being thrown into the atmosphere. The heat transfer difficulties of block polymerization by free radicals can often be handled in continuous processes. For example, reactive extrusion has been described (U.S. Patent Nos. 4,619,979; 4,843,134; and 3,234,303) as a useful block polymerization process because of the high heat transfer capacity due to the large heat transfer area per unit of heat. reaction volume and extremely high mixing capacity. Similarly in US Pat. No. 4,275,177 described, a static, continuous mixing reactor with a large heat transfer area for free-radical block polymerization at controlled temperature has been proposed. As a rule, fuzzy free radical polymerization reactions are not practiced because of their potentially disastrous consequences (Principies of Polymerization, Odian, G., 3rd Edition, iley-Interscience, p. 301. 1991). Generally, methods are used to control the batch block polymerization reaction temperature in batches to prevent leakage (ie, U.S. Patent Nos. 4,220,744, 5,252,662, JP 56185709). Biesenberger et al. , investigated fleeting batch polymerization ("A Study of Chain Addition Polymerizations with Temperature Variations: I. Thermal Drift and Its Effect on Polymer Properties", JA Biesenberger and R. Capinpin, Foiytper Engineering and Science, November 1974, Vol. 14 , No. 11, "A Study of Chain Addition Polymerizations with Temperature Variations: II. Thermal Runaway and Instability A Computer Study ", J. A. Biesenberger, R.

Cápinpin and JC Yang, Polymer Engineering and Science, February 1976, Vol. 16, No. 2, "Study of Chain Addition Polymerizations wth Temperature Variations: III. Thermal Runaway and Instability in Styrene Polymerization-n Experimental Study", DH Sebastian and JA Biesenberger, Polymer Engineering and Science, February 1976, Vol. 16, No. 2, \ A Study of Chain-Addition Polymerizatlons with Temperature Variations: IV. Copolymerizations-Experiments with Styrene-Acrylonitrile, "DH Sebastian and JA Biesenberger, Polymer Engineering and Science, February 1979, Vol. 19, No. 3 Thermal Ignition Phenomena in Chain Addition Polymerizatíons," JA Biesenberger, R. Capinpin, and D. Sebastian, Appli ed Polymer Symposium, No. 26, 211-236, John Wiley & Sons, 1975). In Part II of the series by Biesenberger et al. , potential benefits of the fleeting polymerization are suggested. However, the purpose of the series is to understand the fleeting polymerization to prevent it. The series does not teach practical aspects of the fleeting position useful in an industrial installation, as described in the present invention. Adiabatic conditions are not used in the short polymerizations of Bisenberger et al. Free-radical, continuous polymerization processes have been described, which involve adiabatic polymerization in tubular reactors (US Pat. No. 3,821,330, DE 4235785A1). These methods use more complicated equipment than a batch reactor. Although industrially important, batch reactors (non-continuous) are used less frequently for free-radical block polymerization. The main difficulty with block reactors is that the area of heat transfer per unit volume of reaction is poor and becomes increasingly poor with a larger reactor size. Free radical polymerization methods have been described for the production of acrylate pressure-sensitive adhesives (PSA) in batch reactors where the polymerization chemistry is adjusted to slow down the reaction rate, so that the reaction can be controlled (U.S. Patent No. 5,252,662, JP 56185709). The difficulty with these methods is that the heat transfer area of the batch reactor still depends on the control of the reaction temperature by the removal of heat from the reaction and the prevention of leakage. Therefore, those polymerization methods will not scale directly because the heat transfer capacity varies with the batch reactor size and will be difficult to effect in large batch reaction equipment due to heat transfer. per unit of volume becoming poorer, with the size of the reactor. In addition, control the heat load by decreasing the reaction rate, the cycle time and thus the productivity of the reaction vessel decrease. Batch reactors are desirable over continuous reactors in certain cases. For example, a manufacturer of special chemicals tends to produce multiple products. In this case, batch reactors can be beneficial due to their nature and purposes (that is, they are not necessarily designed for a particular product or chemical as is often the case with continuous equipment). In addition, the economy of a batch reactor is often favorable over a continuous process due to the relative simplicity of the batch reactor equipment. Typically, continuous processes become economical for high volume commercial products (ie polystyrene). In addition, the use of batch reactors for the production of adhesives is common due to the economy of their typical production volumes. The common monomers that are a major contributor to the composition of pressure sensitive adhesives (see below) have relatively high boiling points, and due to their relatively high molecular weights, they have a relatively low heat of reaction per unit mass. Therefore, the adiabatic temperature rises so that the vapor pressure of the resulting mixture during the reaction remains below about 100-300 psig (792.2-2171.8 kPa), the pressures handled by the common batch reactor equipment . The advantages of block polymerization to produce hot melt adhesives over conventional polymerization methods are described in U.S. Patent No. 4,619,979.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a novel method for producing polymer by free-radical block polymerization in a batch reactor. The term "polymerization" as used herein with respect to the present invention also includes telomerization. In addition to the conventional method of directly controlling the reaction temperature, the present invention makes use of the appropriate choice of free radical initiators and the reaction in essentially adiabatic flash reaction cycles. As described herein, a "reaction cycle" is defined as a sequence of a processing wherein the initiators, raonomers (which are not optional in the first reaction cycle, but which may be optional in the subsequent reaction cycle) , and • components are added "optional to the batch followed by one or more essentially adiabatic reactions with optional heating between the essentially adiabatic reactions .. As defined herein," essentially adiabatic "means that the total absolute value of any energy exchanged to or from the batch during the course of the reaction will be less than about 15% of the total energy released due to the reaction by the corresponding amount of polymerization that occurred during the time in which the polymerization occurred.Maticaly expressed, the essentially adiabatic criterion is: where f is approximately 0.15,? HP is the heat of polymerization, x = monomer conversion = (M0-M) / M0 where M is the concentration of the monomer and M0 is the initial monomer concentration, x? is the polymer fraction at the beginning of the reaction and x is the polymer fraction due to the polymerization at the end of the reaction, t is the time, t? is the time at the beginning of the reaction, t is the time at the end of the reaction, and q-, (t), where j = I. . . N is the velocity of the energy transferred to the reaction system from the vicinity of all N sources of energy flow to the system. Examples of energy transfer sources for g7 (t), where j = l. . . N include, but are not limited to, the heat energy conducted to or from the batch from the reactor jacket, the energy required to heat the internal components in the reaction equipment such as the agitator blades and shafts, and the energy of the work introduced when mixing the reaction mixture. In practicing the present invention, having f as close to zero as possible is preferred to maintain uniform conditions within a batch during a reaction (i.e., to maintain homogeneous temperature conditions throughout the batch), which helps to reduce the minimum variations from batch to batch in a particular piece of equipment as well as minimizing variations from batch to batch when reactions are performed in batch reactors of different sizes (ie, scaling up or scaling down the reaction ). Although an essentially adiabatic reaction can be employed, generally two or more essentially adiabatic reaction cycles are employed if the essentially complete conversion of the monomer to polymer is desired. Typically there is cooling between the reaction cycles. The cooling of the reaction mixture between the reaction cycles is typically carried out to prevent the temperature of the reaction mixture from increasing to a point where the product is unstable. This instability can be manifested by discoloration of the polymer, oxidation of the polymer, depolymerization to produce oligomers of low molecular weight, undesirable, etc. The temperature necessary to avoid instability depends in part on the monomers that are used. To avoid such instability the temperature of the reaction mixture is generally kept below about 300 ° C, preferably below about 250 ° C. The reaction conditions are also typically chosen so that at the end of the final reaction cycle, the viscosity of the product is such that the draining of the reaction vessel can be effected (Brookfield viscosity at draining temperatures of less than about 500,000 cetipoises). Optionally, a series of one or more essentially adiabatic reaction cycles can be used to provide a polymer syrup dissolved in the monomer, typically in the range of about 40-95% by weight based on the total weight of the monomers and polymer wherein the unreacted monomer can optionally be separated from the polymer to provide the final polymer product that will effect the reaction to completion. The method of the present invention utilizes one or more thermal free radical initiators, which under the profile of increasing the reaction temperature from the essentially adiabatic reaction conditions, provide free radicals at such a rate that a distribution is obtained. Narrow molecular weight of the polymer. The amount of free radicals generated during the temperature increase profile is controlled by the amounts of each initiator used and the decomposition characteristics by temperature of the selected initiators. Experience has shown that this inventive process is capable of achieving essentially similar or narrower polymer molecular weight distributions than isothermal solution polymerization methods.

As discussed herein, when properly polymerized, block, fugitive, free radical, essentially adiabatic polymerization in a batch reactor can have several advantages: 1) When polymerizing adiabatically, because the reaction equipment is not used to cool the reaction mixture, there is no significant temperature gradient in the walls of the reaction equipment. The temperature gradient can widen the molecular weight distribution of the polymer in a damaging manner by producing a high molecular weight product in the cold boundary layer near the reactor wall, because the kinetics of free radical reaction is well known to those experts in the technique. For example, such high molecular weight components can degrade the performance of the coating of a hot melt adhesive. 2) The reaction equipment used according to the method of the present invention is simple. 3) Because the heat transfer requirements during the reaction are eliminated, the method of the present invention is scaled upward more easily from laboratory scale equipment to large-scale production equipment than the polymerization method of controlled temperature that depends on the available heat transfer area to control the reaction temperature. 4) The continuous polymerization reaction equipment contains several degrees of "backmixing" where there is a distribution of residence time of the reactive material in the reaction equipment. Some of the reaction material may remain in the reaction equipment for extended periods of time degrading the operation of the equipment by continuous attack by the free radical initiator to form the crosslinked or cured polymer. Cured crosslinked gel particles can degrade the performance of the product, such as the smoothness of the coating of a hot melt adhesive. 5) Depending on the polymer and the reaction conditions, essentially complete conversion of the monomer to polymer is possible according to the method of the present invention. Based on the requirements of the specific product, it may be necessary to react at the end of 1-15% by weight of monomer slowly (over a period of one to several hours) to minimize the formation of low molecular weight custom components. that the monomer runs out. The residence times of the order of hours in the continuous reaction equipment, such as an extruder, can be economically impractical.

The present invention provides a method of free radical polymerization of vinyl monomers, comprising the steps of: (a) providing a mixture comprising: (i) vinyl monomers (co) polymerizable by free radicals; (ii) optional chain transfer agent; (iii) optional crosslinking agent; (iv) at least one thermal free radical initiator; (v) optionally a polymer comprising polymerized free radical polymerizable monomers; in a batch reactor; (b) deoxygenating the mixture, wherein step (b) may at least overlap partially with step (c); (c) heating the mixture to a temperature sufficient to generate sufficient free radical initiator from at least one thermal free radical initiator to initiate the polymerization; (d) allowing the mixture to polymerize under essentially adiabatic conditions to give at least one partially polymerized mixture; (e) optionally heating the mixture to generate free radicals from some or all of any initiator that has not been generated by the free radical initiator, and then allowing the mixture to polymerize under essentially adiabatic conditions to give an even more polymerized mixture; and (f) optionally repeating step (e) one or more times. Typically, more than one initiator is present in the mixture of step (a). More typically, 1 to 5 different initiators are present in the mixture of step (a). In some situations, 2, 3, 4 or 5 different initiators are present in the mixture of step (a). The present invention is a method of polymerization of free radical vinyl monomers, comprising the steps of: (a) providing a mixture comprising: (i) vinyl monomers (co) polymerizable by free radicals; (ii) optional chain transfer agent; (iii) optional crosslinking agent; (iv) at least one thermal free radical initiator; (v) optionally a polymer comprising polymerized free radical polymerizable monomers; in a batch reactor; (b) deoxygenating the mixture if the mixture is not already deoxygenated, wherein step (b) may optionally at least partially overlap with step (c); (c) heating the mixture to a temperature sufficient to generate sufficient free radical initiator from at least one thermal free radical initiator to initiate the polymerization; (d) allowing the mixture to polymerize under essentially adiabatic conditions to give at least one partially polymerized mixture; (e) optionally heating the mixture to generate free radicals from some or all of any initiator that has been generated by the free radical initiator, and then allowing the mixture to polymerize under essentially adiabatic conditions to give an even more polymerized mixture; and (f) optionally repeating step (e) one or more times. (g) optionally cooling the mixture; (h) adding to the mixture in the batch reactor at least one thermal free radical initiator, wherein the initiators of step (h) may be the same as or different from the initiators of step (a), optionally radically polymerizable monomers free, optionally crosslinking agents, optionally chain transfer agents, optionally polymer comprising polymerizable free radical polymerizable monomers, wherein the mixture optionally has a temperature lower than that which could generate initiating free radicals of the initiators added in the weight ( h); (i) deoxygenate the mixture if the mixture is not already deoxygenated; (j) optionally heating the mixture to generate initiating free radicals from at least one initiator to further polymerize the mixture if the mixture has a lower temperature that could generate initiating free radicals from the initiators added in step (h); (k) allowing the mixture to polymerize further under essentially adiabatic conditions to give an even more polymerized mixture; (1) optionally heating the mixture to generate free radicals from some or all of any initiator that does not generate initiating free radicals, and then allowing the mixture to polymerize under essentially adiabatic conditions to give an even more polymerized mixture; (m) optionally repeating step (1) one or more times; (n) optionally repeat steps (g) to (m) one or more times. Typically, more than one initiator is present in the mixture of step (a) and step (h). More typically, 1 or 2 different primers are present in the mixture of step (a), 1 to 5 different primers are present in step (h), and 1 to 5 different primers are present in each repetition of the steps (g) to (m) when step (n) is included. More typically, 2 to 5 different primers are present in step (h), and 2 to 5 different primers are present in each repetition of steps (g) through (k) when step (1) is included.

BRIEF DESCRIPTION OF THE DRAWINGS The Figure illustrates the initiator concentrations calculated for the primers used in the second reaction cycle of Example 1. Figure Ib illustrates the calculated values of the -i - '-). the negative value of the derivative of the initiator concentrations with respect to time for the primers used in the second reaction cycle of Example 1. Figure 2 illustrates the batch and jacket temperatures for the two reaction cycles of Example 1. The Figure 3 illustrates the temperature profiles measured for the essentially adiabatic polymerizations of Examples 9, 10 and 11.

DETAILED DESCRIPTION OF THE INVENTION Batch Reactor A batch reactor was used in the method of the present invention. Reacting batch means that the polymerization reaction occurs in a container where the product is drained at the end of the reaction, not continuously while reacting. The raw materials may be charged to the container a moment before the reaction, in the steps during the time during the reaction, or continuously for a period of time while the reaction occurs, and the reaction is allowed to proceed for a period of time necessary to achieve, in this case, the properties of the polymer, including the desired amount of polymerization, molecular weight, etc. If necessary, additives can be mixed in the batch before draining. When the process is complete, the product is drained from the reaction vessel.

A typical batch reactor for this invention will comprise a pressure vessel constructed of material suitable for polymerization, such as stainless steel, which is commonly used for many types of free radical polymerization. Typically, the pressure vessel will have doors to load the raw materials, remove the product, release emergency pressure, pressurize the reactor with inert gas, make vacuum on the upper space of the reactor, etc. Typically, the container is partially surrounded by a jacket through which a heat transfer fluid (such as water) is passed to heat and cool the contents of the container. Typically the container contains a stirring mechanism such as a shaft driven by a motor inserted in the container to which agitator blades are attached. Commercial batch reaction equipment is typically sized in the range of about 10 to about 20,000 gallons (37.9 to 75,708 liters), and may be constructed by the user or may be purchased from various vendors such as Pfaudler-U.S. , Inc. Of Rochester, New York.

Safety Considerations Extreme caution must be exercised to ensure that the reaction vessel can contain the elevated pressure of the reaction mixture at the temperatures encountered, particularly if the reaction should proceed faster or longer than desired due to overload. / lack of accidental loading of initiators. It is also very important to ensure that the reaction mixture will not decompose at the temperatures encountered to form a gaseous product that could dangerously raise the pressure of the container. Small scale adiabatic calorimetric experiments can be used, which for one skilled in the art could easily be able to perform, to determine the fugacity characteristics for the particular monomer and initiator mixtures. For example, the Reactive System Screening Tool (RSST) or the Ventilation Diagram Package (VSP), both available from Fauske and Associates, Inc. of Burr Ridge, Illinois, are devices capable of investigating the characteristics and severity of the fleeting reaction. Additional security considerations are described elsewhere here.

Free Radical Polymerizable Vinyl Monomers A variety of free radically polymerizable monomers can be used according to the method of the present invention. Typically the monomers applicable for this invention, include, but are not limited to, those acrylate monomers commonly used to produce acrylate pressure sensitive adhesives (ASP). The identity and relative amounts of such components are well known to those skilled in the art. Among the particularly preferred acrylate monomers are alkyl acrylates, preferably a monofunctional unsaturated acrylate ester of a non-tertiary alkyl alcohol, wherein the alkyl grcontains from 1 to about 18 carbon atoms. Included within this class of monomers are, for example, isooctyl acrylate, isononyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, dodecyl acrylate, n-butyl acrylate, hexyl acrylate, octadecyl acrylate, and mixtures thereof. Optionally and preferably in the preparation of an ASP, the copolymerizable monomers can be copolymerized with acrylate monomers to improve the adhesion of the final adhesive composition to metals and also improve the cohesion in the final adhesive composition. Strongly polar and moderately polar copolymerizable monomers can be used. The strongly polar copolymerizable monomers include but are not limited to those selected from the grconsisting of acrylic acid, itaconic acid, hydroxyalkyl acrylates, cyanoalkyl acrylates, acrylamides, substituted acrylamides and mixtures thereof. The strongly polar copolymerizable monomers preferably constitute a minor amount, for example up to about 25% by weight of the monomer, preferably up to 15% by weight of the onomer mixture. When strongly polar copolymerizable monomers are present, the alkyl acrylate monomer generally constitutes a larger amount of the monomers in the mixture containing the acrylate, for example, at least about 75% by weight of the monomers. Moderately polar polymerizable monomers include but are not limited to those selected from the group consisting of N-vinylpyrrolidone, N, N-dimethylacrylamide, acrylonitrile, vinyl chloride, diallyl phthalate, and mixtures thereof. A moderately polar copolymerizable monomer preferably constitutes a minor amount, for example, of up to about 40% by weight, more preferably from 5% to 40% by weight, of the monomer mixture. When moderately polar copolymerizable monomers are present, the alkyl acrylate monomer generally constitutes at least about 60% by weight of the monomer mixture.

Macroraonomers are other useful monomers here. In U.S. Patent No. 4,732,808 incorporated herein by reference, the use of free radical copolymerizable macromonomers having the general formula X- (Y) n-Z wherein X is a vinyl group copolymerizable with other monomers in the mixture is described. reaction; And it is a divalent linking group; wherein n may be 0 or 1; and Z is a monovalent polymer portion having a vitreous transition temperature, Tv, greater than about 20 ° C, and a weight average molecular weight in the range of from about 2,000 to about 30,000 and is essentially unreactive under copolymerization conditions. These macromonomers are generally used in mixtures with other copolymerizable monomers. The preferred macro onomer described in U.S. Patent No. 4,732,808 can be further defined as having a group X which has the general formula wherein R is a hydrogen atom or a group -COOH and R 'is a hydrogen atom or methyl group. The double bond between the carbon atoms provides a copolymerizable portion capable of copolyzing with the other monomers in the reaction mixture. The macromonomer includes a group Z which has the general formula wherein R 'is a hydrogen atom or a lower alkyl group (typically from Ci to C4), R3 is a lower alkyl group (typically from Ci to C4), n is an integer from 20 to 500 and R4 is a monovalent radical selected from the group consisting of and -CO? R6 wherein R3 is a hydrogen atom or a lower alkyl group (typically from Ci to C4) and Rb is a lower alkyl group (typically from Ci to C <). Preferably, the macromonomer has a general formula selected from the group consisting of 0 O H -C-0-CH 2 -CH 2 -NH-C-O-C-CH 2 - Z wherein R7 is a hydrogen atom or a lower alkyl group (typically from Ci to C4).

The preferred macromonomer is a functionally-terminated polymer that has a single functional group (the vinyl group) and is sometimes identified as a polymer "semitelequélico". (Vol. 27"Functionally Terminal Polymers via Anionic Methods" D. N. Schultz et al., Pages 427-440, Anionic Polymeri za ti on, American Chemical Society [1981]). Such macromonomers are known and can be prepared by the methods described by Milkovich et al., In U.S. Patent Nos. 3,786,116 and 3,842,059, for the description of the preparation of the vinyl terminated macromonomers. As described herein, the vinyl-terminated macromonomer is prepared by anionic polymerization of polymerizable monomer to form a latent polymer. Such monomers include those having an olefinic group, such as the vinyl-containing compounds. The latent polymers are conveniently prepared by contacting the monomer with an alkali metal hydrocarbon or alkoxide salt in the presence of an inert organic solvent, which does not participate in or interfere with the polymerization process. Monomers that are susceptible to anionic polymerization are well known. Exemplary species include aromatic vinyl compounds such as styrene, alpha-ethylstyrene, vinyl toluene and their non-aromatic vinyl isomers or compounds such as methyl methacrylate. Other monomers susceptible to anionic polymerization are also useful. The purpose of using a copolymerizable macromonomer includes but is not limited to allowing the hot melt coating of the ASP, but also increasing the cohesive strength of the cold extruded ASP sheet by the interaction of the remaining Z portions on the polymer skeleton. The amount of macromonomer used is generally within the range of about 1% to about 30%, preferably 1% to 7% of the total weight of the monomersAs mentioned above the "monomer" is defined herein to include the macromonomer. The optional use of such macromonomers was included within the scope of the present invention. A particular advantage of the present invention is the ability to successfully copolymerize such macromonomers in the polymer backbone. In conventional, low temperature, isothermal block polymerization, as the polymerization proceeds, the macromonomer may precipitate due to the inability of the macromonomer in the polymer accumulation, preventing the necessary polymerization of the macromonomer in the polymer backbone. In the practice of the present invention, due to the high temperatures obtained at high conversion, the successful use of macromonomers copolymerizable by free radicals has been demonstrated. Other monomers for which the method of the invention can be expected to be applicable include other members of the vinyl family such as the fraonoalkenyl aromatic monomers including but not limited to those selected from the group consisting of styrene, alpha-methylstyrene, vinyltoluene , para-methylstyrene, tertiary butylene and mixtures thereof. Other "acrylic monomers" for which the process of the invention is expected to be applicable include but are not limited to those selected from the group consisting of methacrylate esters such as methyl methacrylate, n-butyl methacrylate, methacrylate hydroxyethyl, and dimethylaminoethyl methacrylate; and methacrylic derivatives, such as methacrylic acid, and salts thereof and methacrylonitrile. It is expected that other suitable non-acrylic ethylenic monomers include vinyl esters such as vinyl acetate and maleic acid.

Chain Transfer Agents Chain transfer agents that are well known in the polymerization art can also be included to control the molecular weight or other properties of the polymer. The term "chain transfer agent" as used herein also includes "telogens". Chain transfer agents suitable for use in the method of the invention include but are not limited to those selected from the group consisting of carbon tetrabromide, hexanbromoethane, bro-otrichloromethane, 2-mercaptoethanol, t-dodecyl mercaptan, isooctylthioglycoate, 3-mercapto -l, 2-propandiol, eumeno and mixtures thereof. Depending on the reactivity of a particular chain transfer agent and the amount of chain transfer desired, typically from 0 to about 5 weight percent chain transfer agent, preferably from 0 to about 0.5 per cent, was used. percent by weight, based on the total weight of the monomers.

Crosslinking or Curing Crosslinking or curing can also be used in the method of the invention. For example, in the hot melt ASP manufacturing technique, ASPs often require a curing step after they have been extruded into a sheet to give them good bond strength and strength. This step, known as posteurado, usually comprises exposing the extruded sheet to a form of radiant energy, such as an electron beam, or ultraviolet light with the use of a chemical crosslinking agent.

Examples of suitable crosslinking agents include but are not limited to those selected from the group consisting of photocrosslinking agents of the hydrogen abstraction type such as those based on benzophenones, acetophenones, anthraquinones and the like. These crosslinking agents can be copolymerizable or non-copolymerizable. Suitable examples of suitable non-copolymerizable hydrogen abstraction crosslinking agents include benzophenone, anthraquinones, and radiation-activatable crosslinking agents such as those described in US Pat. No. 5,407,971. Such agents have the general formula wherein W represents -O-, -N-, or -S-; X represents CH3- or phenyl; Y represents a ketone, ester, or amide functionality; Z represents a polyfunctional organic segment that does not contain more photoabstractable hydrogen atoms than the hydrogen atoms of a polymer formed using the crosslinking agent; m represents an integer from 0 to 6; "a" represents 0 or 1; and n represents a whole number 2 or greater. Depending on the amount of crosslinking or curing desired and the efficiency of the particular crosslinker used, non-copolymerizable crosslinking agents are typically included in the amount of from about 0% to about 10%, and preferably in the range of about 0.05% up to about 2%, based on the total weight of the monomers. Examples of suitable, copolymerizable hydrogen abstraction crosslinking compounds include monoethylenically unsaturated aromatic ketone monomers free of orthoaromatic hydroxyl groups. Examples of suitable free radical copolymerizable crosslinking agents include but are not limited to those selected from the group consisting of 4-acryloxybenzophenone (ABP), para-acryloxyethoxybenzophenone, and para-N- (methacryloxyethyl) -carbamoylethoxybenzophenone. the copolymerizable chemical crosslinking agents are typically included in the amount of from about 0% to about 2%, and preferably in an amount from about 0.025% to about 0.5%, based on the total weight of the monomers. Other useful copolymerizable crosslinking agents are disclosed in U.S. Patent No. 4,737,559.

Solvents In many cases, free radical polymerization can take place without solvents, i.e., true block polymerization wherein the polymer formed as well as the monomers by themselves are all miscible. However, the monomers may in some cases require a solvent to copolymerize. For example, acrylamides are dissolved in a small amount of solvent to make them miscible with isocyclic acrylate. Therefore, the process of the invention includes, within its scope, the use of solvents which do not react in the free radical polymerization that is being carried out. Such solvents usually comprise less than about 20 percent based on the total weight of the mixture. Useful solvents are those that are miscible in the mixture, including but not limited to organic solvents such as toluene, hexane, pentane and ethyl acetate. The solvents can also improve the process of the invention, reducing polymer viscosity at the end of the polymerization to facilitate draining or further processing. Unless necessary, however, the addition of solvents is not preferred because it can have the same disadvantages as solution polymerization, although to a lesser degree when the concentration of solvent is low.

Optional Polymer Optionally, the polymer can be dissolved in the reaction mixture before the first essentially adiabatic reaction cycle. Alternatively and / or in addition the optional polymer can be included in the subsequent essentially adiabatic reaction cycles. Such a polymer can be included to modify the molecular weight distribution, molecular weight or properties of the final polymer product after the reaction is complete and will generally not react during the polymerization of the process of the invention. Although not required, the polymer will generally be comprised of the same monomers that must react in the reaction mixture comprising the polymer, monomers, initiators, optional chain transfer agents, etc. The polymer dissolved in the monomers before the first reaction cycle will typically be included in the range of from about 0% to about 50% by weight and preferably less than about 0% to about 30% by weight, based on the weight total of the monomers plus the polymer. The use of polymer syrups to produce acrylic polymers is explained in U.S. Patent No. 4,181,752.

Initiators by Free Radicals Many initiators by free, thermal, possible radicals are known in the polymerization technique of vinyl monomer and can be used in this invention. The thermal initiators of free radical polymerization that are useful here are organic peroxides, organic hydroperoxides, and initiators with an azo group which produce free radicals. Useful organic peroxides include but are not limited to compounds such as benzoyl peroxide, di-t-amyl peroxide, t-butyl peroxybenzoate, and di-cu-lyl peroxide. Useful organic hydroperoxides include but are not limited to compounds such as t-amyl hydroperoxide and t-butyl hydroperoxide. Useful azo group initiators include but are not limited to the VAZOMR compounds manufactured by DuPont, such as VAZOMR 52 (2, 2'-azobis (2, -di-ethylpentanitrile)), VAZO ™ 64 (2, 2'-azobis) (2-methylproponanitrile)), azoMR 67 (2, 2'-azobis (2-methylbutannitrile)), VAZOMR 88 (2, 2'-azobis (cyclohexanecarbonitrile)). When the initiators have been mixed into the monomers, there will be a temperature above which the mixture begins to react substantially (temperature rise rate typically greater than about 0.1 C / min for essentially adiabatic conditions). This temperature, which depends on factors including the monomers that are reacting, the relative amounts of the monomers, the particular initiator that is used, the amounts of initiators used, and the amount of any polymer and / or any solvent in the reaction mixture, will be defined here as the "fugacity appearance temperature". As an example, when the amount of initiator is increased, its temperature of occurrence of the fugacity in the reaction mixture will decrease. At temperatures below the onset temperature of the fugacity, the amount of the polymerization process will be practically negligible. At the temperature of occurrence of the fugacity, assuming the absence of inhibitors of the reaction and the presence of essentially adiabatic reaction conditions, the polymerization by free radicals begins to proceed at a significant speed and the temperature will begin to accelerate upwards, beginning the reaction of transience. According to the present invention, a sufficient amount of initiators was typically used to carry out the polymerization at the desired temperature and conversion. If too much initiator is used, an excess of low molecular weight polymer will be produced thereby producing a broader molecular weight distribution. The low molecular weight components can degrade the operation of the polymer product. If very little initiator is used, the polymerization will not proceed appreciably and the reaction will stop or proceed at a non-practical speed. The amount of an Individual initiator used depends on factors including whether its efficiency, molecular weight, the molecular weights of the monomers, the heats of reaction of the monomers, the types and amounts of other initiators included, etc. The amount of total initiator, which for all initiators, was typically used in the range of about 0.0005% by weight to about 0.5% by weight and preferably in the range of about 0.001% by weight to about 0.1% by weight in based on the total weight of the monomers. When more than one initiator is used in the reaction, such as when the first initiator is depleted during the essentially adiabatic reaction (with the corresponding increase in the reaction temperature), the second initiator can be selected so that it is thermally activated when the first initiator run out That is, when the first primer runs out, the reaction brings the reaction mixture to the temperature at which the leak appears by the second initiator in the reaction mixture. A superposition is preferred such that before one initiator is completely exhausted the other initiator is activated (reach the temperature at which the fugacity appears). Without an overlap, the polymerization rate can be decreased or stopped essentially without external heating to bring the mixture to the temperature of occurrence of the fugacity of the next initiator in series. Thus, the use of external heating overrides one of the benefits of the process of the invention by adding the potential of a non-uniform temperature distribution in the reaction mixture due to external heating. However, polymerization will still occur under essentially adiabatic conditions, which is an important feature of the invention. Until the temperature increases towards the onset temperature of the fugacity for an individual initiator in the batch, the initiator is essentially asleep, does not decompose appreciably to form free radicals. It will remain asleep until the reaction temperature increases towards its temperature at the appearance of the fugacity in the reaction mixture and / or until external heat is applied. The succession of the depletion of an initiator and another that reaches its temperature of occurrence of the fugacity can continue as the temperature rises for virtually any number of thermal initiators in the reaction system. In the limit, a different one can be used with an almost complete superposition of the active temperature ranges between the adjacent primers in succession to carry out the polymerization and the corresponding adiabatic temperature rise. In this case, the amount of each initiator used might need to be virtually infinitesimally small so as not to extend the molecular weight distribution. Practically, to minimize the raw material handling requirements, a reasonable minimum number of initiators should be used to achieve the desired amount of adiabatic polymerization and obtain the necessary polymeric properties. Typically from 1 to 5 different primers (more typically from 2 to 5) are used during a particular reaction cycle. In some circumstances it may be advantageous to use 2, 3, 4, or 5 different primers per reaction cycle. To estimate the amount of superposition between successive initiators in a series during essentially adiabatic polymerization, standard polymerization modeling techniques can be employed (eg, WH Ray, "On the Mathematical Modeling of Polymerization Reactors", J. Macromol. Sci. Macromol Chem, 08 (1), 1, 1972) and graphs similar to those shown in Figures la and Ib can be made.

Alternatively, an essentially adiabatic polymerization can be conducted (i.e. using a small scale adiabatic reaction calorimeter) and the temperature profile for a particular set of primers can be measured. Based on the known decomposition rates of the initiators and the measured temperature profile, the concentration of each initiator against time can be calculated. The calculation involves solving the following differential equation for It versus the time for each initiator i in the essentially adiabatic polymerization (i = l a n, where n is the number of initiators in the reaction system): Here It represents the concentration of initiator i at a given time, t represents time, and a is the temperature-dependent decomposition rate constant for initiator i. The constant of velocity ki is commonly represented by an Arrhenius relation of the form 1exp. { -Ea? (1 / T - 1 / Tref) / R} , where Ea # i is the activation energy of the initiator decomposition i, T is the absolute temperature, ref, i is the decomposition rate coefficient at a chosen reference temperature such as Tre.f = 294 K, and R is the universal constant of gases. For clarity, the index i for each initiator will be defined numbered from 1 to n ordered from the lowest temperature to the highest temperature for each initiator i that produces a half-life of one hour. The constants Ea ,? and ,,. f, j. they can be estimated by knowing the decomposition characteristics dependent on the temperature of initiator i, data commonly available from commercial manufacturers of free radical initiators. For example, knowing the half-life of the initiator i at two different temperatures, Ea (1 and kref,?) Can be estimated.

Ix against time, multiplying It at every time by k, at that time it can be used to determine ~ l ("d * rl?" J against the time position direct substitution in the velocity equation for the decomposition of the initiator, Equation 2. By plotting -I- against the temperature, the temperature overlap intervals of each initiator are clearly illustrated.The calculated initiator concentrations shown in Figure 1 and the values of - (-> .j shown in Figure Ib were obtained. using the measured temperature profile of the second reaction cycle of Example 1. The exhaustion rate equation of the previous initiator was resolved with the values of Eari and kcef, t for primers Vazo 52, Vazo 88 and di-t-amyl peroxide estimated on the basis of was resolved with the values of Ea,? and kr? f, and for primers Vazo 52, Vazo 88 and di-t-amyl peroxide estimated based on the half-life data available from the manufacturers of the initiator (the values used are presented in Table 1 below). As a close approximation, equation 2 for each primer was solved analytically at one minute intervals considering that the reaction temperature was constant at the measured value until the next temperature measurement was available. This method of calculation is accurate when it is solved over sufficiently small time intervals. Alternatively, standard numerical solution techniques can be used to calculate the estimated initiator concentrations, Il f based on the measured adiabatic polymerization temperature profile and the known initiator decomposition rate data (see Carnahan, et al., " Applied Numerical Methods ", Wiley 1969).

TABLE 1 Di-t-amyl peroxide (i = 3) 1.10 e-12 37.7 In the method of the present invention, a preferred minimum and maximum superposition of active temperature ranges of two or more initiators during an essentially adiabatic reaction will be as follows.

Minimal Overlay of the Initiator It is preferred that before ~ \ ~ Jr \ for at least one (preferably for each) initiator i (i = n-l, n >; 1, where i = l, ..., n) decreases to approximately 10% of its maximum value, the value of -i-¡üj for the next initiator to reach the temperature of the occurrence of the fugacity in the series. it will increase to at least about 20% of its maximum value, as the reaction temperature increases due to the essentially adiabatic polymerization. By reacting in this manner, the essentially adiabatic polymerization will proceed without the need for heating between the temperatures of occurrence of the fugacity of the initiators.

Maximum Overlap of Initiator It is preferred that before -frJ for at least one (preferably for each) initiator i in a series (i> 1, n> 1, where i = l, ..., n) reaches approximately 30% of its maximum value, the previous initiator in the series has already reached its maximum value - ("d"), when the reaction temperature increases due to the essentially adiabatic polymerization, reacting in this way, the number of initiators used will be kept at a reasonable minimum number A particular initiator used is selected based on its thermal decomposition characteristics, for example, di-cumyl peroxide and di-t-amyl peroxide have characteristics of decomposition by similar temperature to produce free radicals (ie half-lives similar to various temperatures) and can be reasonable substitutes for each other in some circumstances. temperature, other considerations in the selection of the initiator may include initiator toxicity, cost and potential side reactions in the polymerization system (such as minimization of undesirable crosslinking of the polymer). Typical initiators are activated when the temperature is increased, include: VazoMR 52 (2,2'-azobis (2,4-dimethylpentannitrile)), VazoMR 88 (2,2'-azobis (cyclohexanecarbonitrile)), diol peroxide t-amyl and t-amyl hydroperoxide. These initiators, for the common monomers that are reacting, typically "separate" in their temperature decomposition characteristics to superpose sufficiently to effect the adiabatic polymerization without the need for external heating. Different or additional initiators may be necessary, depending on the monomers used. Factors affecting the initiators employed include but are not limited to the reaction rate of the monomers, the heat of reaction of the monomers and the heat capacity of the reaction mixture. In the case where there is more than one reaction cycle, the initiators for the first essentially adiabatic reaction cycle are typically selected to bring the reaction to a temperature / conversion level where: 1) The polymerization reaction is virtually stopped when the initiators have been essentially depleted (ie, that the initiators have been exhausted by more than 99%). The temperature of the reaction mixture is such that the thermal polymerization of the monomers (polymerization in the absence of free radical initiators) in the polymer / monomer reaction mixture is practically negligible. It is important that the reaction be stopped with the transfer of available heat from the reactor jacket (and potentially increase with external cooling, such as external cooling of the reaction fluid pump through a heat exchanger, etc.). 2) The viscosity of the solution is such that when the reaction mixture is cooled before the next reaction cycle, the following initiators, optional chain transfer agents, optional additional monomers, optional polymer, etc., may be mixed in the batch. . This viscosity will typically be less than about 200,000 centipoise (Brookfield viscosity at the mixing temperature) for a common batch reactor system.

Method of the Invention Typical reactions with the process of the invention proceed as follows. The monomers are charged to the reactor in the desired amounts. The temperature of the reaction vessel must be sufficiently cold, so that virtually no thermal polymerization of the monomers occurs and also sufficiently cold so that polymerization virtually does not occur when the initiators are added to the batch. Care must also be taken to ensure that the reactor is dry, in particular, free of any undesirable volatile solvents (such as reactor cleaning solvent)., which could potentially dangerously raise the pressure of the reaction vessel when the temperature increases due to the polymerization heat. Initiators, optional chain transfer agents, optional polymer, optional curing or curing agents / optional solvent, etc., are also charged to the reactor. Before heating the reaction mixture as described below (or optionally simultaneously while heating the batch) after adding all the components to the batch as described above, the batch is purged to remove oxygen, a polymerization inhibitor by free radicals. Deoxygenation processes are well known to those skilled in the art of free radical polymerization. For example, deoxygenation can be carried out by bubbling an inert gas such as nitrogen through the batch to displace the dissolved oxygen. After completing the deoxygenation, the space in the upper part of the reactor is typically pressurized with an inert gas such as nitrogen to a level necessary to suppress the boiling of the reaction mixture when the temperature rises during the reaction. The inert gas pressure also prevents oxygen from entering the polymerization mixture through possible small leaks in the reaction equipment while the polymerization is in progress.

The heating provided by the jacket on the reactor, the temperature of the reaction mixture is typically raised to or in a range from about 1 ° C to about 5 ° C above the leak appearance temperature with sufficient mixing in the batch. so that it has an essentially uniform temperature in the batch. The batch temperature controller is typically set temporarily to maintain the batch at the temperature at which the leak appears. Once the temperature of the jacket begins to fall as necessary to maintain the batch at the onset temperature of the fugacity this indicates that the polymerization has begun. The reaction can not proceed immediately when the batch is brought to the temperature of occurrence of the fugacity, because it can take time to exhaust the reaction inhibitors that are typically transported or shipped with the monomer (to prevent undesirable polymerization during shipping or transportation). and handling), other impurities in traces, or any amount of oxygen still dissolved in the reaction mixture. As soon as the jacket temperature declines, the temperature control system of the reactor jacket is calibrated to follow the batch temperature when it increases, due to the reaction, to facilitate essentially adiabatic reaction conditions. In the practice of the method of the invention, it has been found beneficial that the jacket has a tracking of about 1 ° C to about 10 ° C above the batch to heat the reactor walls of the jacket as opposed to heating the walls of the jacket. Reaction heat reactor of the mixture, making the reaction system more adiabatic. It is recognized that perfect adiabaticity is probably not achievable because there will typically be a small amount of heat transfer from the reaction medium to the blades of the internal agitator shaft as well as the mixing deflectors in the reactor. In the practice of this invention the effect of heat loss to heat the shaft and paddles of the agitator, deflectors, temperature probes, etc., has been found to be negligible. An alternative heating method could be to gently heat the batch beyond the onset temperature of the leak with the heat introduced by the jacket to heat the batch at a rate of about 0.1 ° C / min up to about 0.5 ° C / min and Continue heating through the reaction cycle (similar to the previous heating method with jacket tracking from about 1 ° C to about 10 ° C above the batch temperature). As in the above heating method, continuous heating through the reaction cycle could serve to divert heat loss to the reaction equipment and maintain essentially adiabatic reaction conditions. In the practice of the present invention, the first heating method described above appears to be preferable because it ensures that the reaction will always start at the same temperature, which seems to produce a more reproducible product from batch to batch. Once the reaction temperature has reached a peak, due to the depletion of the thermal initiators, as well as the negligible reaction of the monomers of the thermal polymerization, the polymer content at this point is typically around 30-80% by weight. weight based on the total weight of the monomers and the polymer. If desired, the polymerization cycles can be stopped at this point and the unreacted monomer can be separated from the reaction mixture or further polymerized in other equipment. Separation apparatuses for the purpose of removing residual monomer are well known to those skilled in the polymerization art. A potential separation apparatus is an extractor-extruder that operates with ventilated sections to vacuum chambers where the polymer can be condensed and optionally reused in subsequent polymerizations. Typical extruders-extruders are referred to in Modern Plastics Encyclopedia, Volume 45, October 1968 and Volume 46, October 1969, both published by MawGraw-Hill.

A potential benefit of stopping the polymerization without completing the reaction is that it has been found that the molecular weight distribution widens when the conversion increases until the conclusion of the reaction. The properties requirements of the products could guarantee the effort and extra cost of separating against letting react until the conclusion of the reaction. Another reaction to cease the polymerization process at a partial conversion could be to limit the viscosity of the solution to manageable levels. For example, as the molecular weight of the polymer increases, the viscosity of the solution will increase. If a high molecular weight polymer and the melt viscosity are to be produced a 100% conversion is not manageable, ie greater than about 200,000 to about 500,000 centipoise (Brookfield viscosity at temperature), the reaction stoppage to less than 100% conversion could be beneficial. When the reaction system is to be further polymerized in one or more essentially adiabatic reaction cycles, the batch temperature will typically be cooled before beginning the next reaction cycle. Generally, the batch is cooled to about 5-20 ° C below the onset temperature of the initiator's fugacity used in the next reaction cycle. If more than one initiator is used the batch temperature is typically cooled to less than about 5-20 ° C below the onset temperature of the initiator leak having the lowest leak temperature. When the partially polymerized reaction mixture is cooled, its viscosity will increase. Optionally, if necessary, additional monomers may be added to the batch before being completely cooled to compensate for the increase in viscosity. Typically, if necessary, a relatively small amount will be added. It is preferred to charge additional monomer in an amount of less than about 30% by weight of the amount of monomer added in the first reaction cycle. While the batch is cooling or when it has been cooled to the desired temperature, additional monomers may be optionally added to adjust the monomer ratios to compensate for the unequal reactivity ratios of the monomers in the above reaction cycle. Similarly, monomers not included in a previous reaction cycle may be added to design polymer properties as necessary. The monomer addition can also be carried out as a correction of the process to compensate for slight variations from batch to batch in the reaction conversion amount obtained in a previous reaction cycle.

When the batch has cooled to the desired temperature, additional primers are added to the batch. Optionally, an additional chain transfer agent can be added. The adjustment of the amount of chain transfer agent can provide a correction in the process for the molecular weight of the product obtained from the above reaction cycle. Other additives, including optional photo-crosslinking agents, optional polymer, optional solvent, etc., can also be added at this time. The batch is deoxygenated, heated to the onset temperature of the initiator fume having the lowest fugacity appearance temperature, and reacted essentially in an adiabatic manner as described above for the above reaction cycle. If necessary, additional reaction cycles can be carried out to continue increasing the conversion to the desired level. Optionally, when all the reaction cycles are complete, the unreacted monomer can be separated from the batch by drawing vacuum on the hot reaction product in the batch reactor by an external vacuum equipment such as a vacuum pump and optionally condensing the vapors of the monomer in an external heat exchanger with cooling.

Optional additives include but are not limited to those selected from the group consisting of plasticizers, tackifiers, antioxidants, stabilizers and mixtures thereof, can be added at this time by mixing one or more of them in the molten polymer product. The identity and relative amounts of such components are well known to those skilled in the art. For example, the antioxidant / stabilizer IrganoxMk 1010 (tetracis (methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate)) methane), manufactured by Ciba-Geígy Corporation, can be mixed in the polymer to increase the temperature stability of the polymer. Antioxidants are typically used in the range of about 0.01% to about 1.0% based on the total weight of the polymer product. The viscosity of the reaction mixture at the temperature at the end of the final reaction cycle is preferably less than about 200,000 to about 500,000 centipoise (Brookfield viscosity at the draining temperature) to allow draining of the polymer melt in the reactor and optionally mixing the additives in the batch. Typically, an inert gas pressure (such as nitrogen) can be used in the upper reactor space to facilitate drainage of the reactor product.

After the reaction mixture is drained, an apparatus such as an extractor-extruder can be used to remove the unreacted monomer and / or any solvent that has been optionally added to the batch, or further processed the polymer by mixing with additives comprising plasticizers , adherents, antioxidants and / or stabilizers, and extruding the polymer in the physical form that is intended to be used (ie in the form of a sheet for an ASP). The invention will be further clarified by considering the following examples, which are intended to be purely exemplary. All parts, percentages, relationships, etc., in the examples and elsewhere herein are by weight unless otherwise indicated.

Preparation of the Sample for the Adhesion Test The copolymers made for the ASP were dissolved in 50% ethyl acetate by weight of polymer plus ethyl acetate. The solutions were coated with a blade on a primed polyester film with a thickness of 38 microns to approximately a dry coating thickness of 25 microns (the exact thickness is reported in the examples below). The copolymeric ASPs thus coated were immediately dried for ten minutes in an oven at 65 ° C followed by optional exposure to ultraviolet (UV) light to cure the adhesive (see "UV Curing Equipment" below) and then aged. for approximately sixteen hours at 22 ° C and a relative humidity of 50% before carrying out the test. The coated sheet thus prepared was ready to be tested as described under "Film Adhesion Test".

UV Curing Equipment Two pieces of different equipment were used as sources of UV radiation to cure the adhesive samples in the following examples. They were the PPG UV processor, PPG Industries, Inc., Blainfield, Illinois, and the Fusion Unit of Fusion Systems Corp., Rockville, Maryland. The PPG UV processor is equipped with two medium pressure mercury lamps which have a spectral output of between 240 and 740 nm with emissions mainly in the output range of 270 to 450 nm. The Fusion Systems Curing Unit uses' UV lamps that have a power supply of 300 watts / inch (118.1 watts / cm). The "H" bulbs available from Fusion Systems Corp. were used. The amount of the UV radiation dose was controlled by the respective device power supply devices, the transport speed device, and the number of passes of the adhesive under the ultraviolet light.

Film Adhesion Test The adhesion of the film was measured as the force required to remove a flexible sheet material coated from a test panel, measured at a specific angle and speed of removal. The details of this test are given in "Test Methods for Pressure Sensitive Tapes" Eighth Edition, Revised in August 1980. The procedure is arized as follows: 1. A 12.7 mm wide coated sheet was applied to the horizontal surface of a Clean glass test plate with a centerline of at least 12.7 centimeters in firm contact. A 2 kg hard rubber roller was used to apply the strip or tape. 2. The free end of the coated strip was folded back almost touching itself so that the angle of removal is 180 °. The free end was attached to the scale of the adhesion tester. 3. The glass test plate was attached to the table of an IMASSMR adhesion testing machine manufactured by Instrumentors, Inc., which is capable of moving the table away from the scale at a constant speed of 2.3 meters per minute. 4. The force required for the removal was reported as an average of a range of numbers recorded by the test apparatus. This value was reported as Newtons per 100 millimeters (N / 100 mm) in width according to PSTC-1.

Test of Resistance to Cutting-Retention Power (PSTC No. 7 - Eighth Edition - 1985) This test measures the time required to detach an ASP tape from a standard flat surface in a direction parallel to that surface under the stress of a load constant, standard. The value was expressed in units of time (minutes) per unit area. This is a measure of the cohesive strength of the polymeric material. The conditions under which the examples were measured in this application were as follows: 1. Surface = stainless steel panel 2. Tape area = 12.7 mm by 12. 7 mm 3. Panel area - 178 ° 4. Constant load = 1 kilogram * 2 ° less than 180 ° to negate any detachment forces thus ensuring that only shear forces are measured. PSTC No. 7 is found in "Test Methods," Pressure Sensitive Tape Council, 1800 Pickwick Ave., Olenview, Illinois 60025 (August 1985) Molecular Weight and Molecular Weight Distribution The characterization of the molecular weight distribution of the polymers it was carried out by size exclusion chromatography, also known as gel permeation chromatography (GPC). The GPC test methods are explained in Modern Si ze Exclusi ón Liquid Chro a tography, Practice of Gel Permea ti on Chroma tography, John Wiley & Sons 1979. In the examples, the term Mw means the weight average molecular weight, and the term Mn means the numerical average molecular weight, both terms which are well understood in the polymer art. The term polydispersity is the ratio of Mw / Mn. The samples were prepared for GPC as follows: (1) The polymer sample was dissolved at a concentration of 20 mg / ml in tetrahydrofuran at room temperature to make a total of about 10 ml of solution. (2) If the polymer contained acrylic acid, then the solution was treated with diazomethane saturated in diethyl ether by adding 5 ml of such solution by dripping while stirring. If there was no acrylic acid present in the polymer, one proceeded directly to Step 5 below. (3) The resulting mixture was reduced to approximately 1 ml volume by evaporation under a stream of air. (4) Tetrahydrofuran was added to bring the sample to a volume of 10 ml. (5) The resulting fluid was filtered through a Teflon ™ filter, < 0.45 micrometer in a syringe to avoid blockage of the GPC column by the sample. (6) The resulting filtrate was used for the chromatographic analysis. A model 150 Waters ALC / GPC, available from Millipore Corp., Milford, MA, operated at 45 ° C with a carrier stream of tetrahydrofuran at a flow rate of 1 ml / min (sample injection volume of 200 microliters) was used. ) for the analysis by GPC. A refractive index detector was used. Polystyrene standards from Polymer Laboratories, Ltd., were used in the molecular weight range of 162 to 3,150,000. Six columns (Phenogel ™ columns from Phenomenex Co.) with pore sizes from 100 A to 106 A were used.

Conversion of the Monomer to Polymer In the following examples, the degree of polymerization, or the amount of conversion of monomer to polymer was measured by one of two methods: gas chromatography (GC) or by the measurement of solids. Two different GC methods were employed. A GC method was used when only the% IOA (% of isooctyl acrylate monomer in the sample by weight) was reported, and a different GC method was used when the% IOA and% AA were reported. (% acrylic acid monomer in the sample by weight). % of IQA A Hewlett-Packard Model 5890 Gas Chromatograph was used to measure the percentage by weight of unreacted isooctyl acrylate (% IOA) under the following conditions: Column - Type: Stainless steel Length: 12 feet (3,658 m ) Internal Diameter: 1/8 inch (0.3175 cm) Package manufactured by Supelco Co., from Bellefonte, PA (20% SP2100 in liquid phase, Supelcoport solid support 80/100 mesh) Oven temperature - 210 ° C (Isothermal) Detector - Thermal conductivity (TCD) Sensitivity parameter: High Injector temperature - 250 ° C Detector Temperature - 300 ° C Sample Size - 3 microliters Test Time - 5 minutes Gas Carrier - Helium An internal standard solution containing the monomer (for example isooctyl acrylate) to be detected and a substance that was prepared was prepared. The detector was determined to have a similar response and a non-similar elution time, called internal known addition compound (ISSC) in a vial. The concentration in the monomer standard was tested and that of the ISSC is both 1.00% by weight in a suitable solvent. The standard was injected. Next, the area under the analyte peak and under the ISSC floor was measured on the time plot versus the response of the chromatographic assay detector of the standard. The calculations were then made to determine the relative factors of detector response for the two compounds. An aliquot of the unknown residual monomer sample was diluted to 10% by weight with a suitable solvent to reduce the viscosity of the sample. ISSC was added to the mixture at a weight equal to 5% of the weight of the sample before diluting with the solvent. The sample was injected. Next, the area under the analyte peak and under the ISSC peak was measured on the time versus counter plot of the chromatographic assay detector of the diluted sample. Next, calculations were made to determine the residual levels of the monomers in the sample using the areas measured in the relative response factors determined above.

% IOA and% AA A Hewlett-Packard Model 5890 gas chromatograph was used to measure the percentage by weight of unreacted isooctyl acrylate (% IOA) and unreacted acrylic acid (% AA) with the following conditions: Column - Type: Capillary Length: 15 meters Internal Diameter: 0.53 mm Liquid Phase: HP-FFAP (manufactured by Hewlett-Packard) Film Thickness: 3 micrometers Divided Flow - 80 ml / min at 50 ° C Temperature Program from the oven: Initial Temperature - 50 ° C Initial Time - 0.5 minutes Detector - Flame Ionization (FID) Injector temperature - 250 ° C Detector temperature - 300 ° C Sample size - 1 microliter Test time - 5 minutes Gas carrier - Helium - 10 ml / min at 50 ° C diluted a sample aliquot of residual residual monomer levels at 10% by weight with acetone to reduce the viscosity of the sample. An external standard solution containing the residual monomers (e.g., isooctyl acrylate, acrylic acid) was prepared at known concentrations in acetone in a flask. The concentrations of the monomers in the standard were selected close to the expected concentrations of the monomers in the diluted sample of residual residual monomers. Equal volumes of the standard solution and the diluted sample were injected under identical conditions. Next, the areas under the analyte peaks were measured on the time versus counter plot of the chromatographic assay detector of the standard solution and the diluted sample. The calculations were then made to determine the residual levels of the monomers in the sample.

Measurement of Solids A sample of approximately 0.5-1.0 gm of polymer was placed in a small can. The can containing the polymer was placed in a convection oven at 120-130 ° C for at least three hours, or until no further weight loss could be measured by evaporation. For the measured weight loss of evaporated monomer, the amount of monomer converted to polymer (expressed in percent in the examples below) could be calculated.

Inherent Viscosity The inherent viscosities (IV) reported herein were obtained by the conventional methods used by those skilled in the art. The IVs were obtained using a Cannon-Fenske # 50 viscometer in a controlled water bath at 25 ° C, to measure the flow time of 10 ml of a polymer solution (0.2 g per deciliter of polymer in ethyl acetate) . The test procedure followed and the apparatus used are described in detail in Textbook of Polymer Sci ence, F. W. Billmeyer, Wiley-Interscience, Second Edition, 1971, Pages 84 and 85.

EXAMPLE 1 This example illustrates the use of the process of the invention to produce a hot-melt J acrylate pressure-sensitive adhesive (ratio of isooctyl acrylate / acrylic acid monomer: 90/10). Two essentially adiabatic reaction cycles were used in combination with a vacuum extraction of the unreacted monomer, f residual, after completing the reaction cycles. The following components were charged to a batch reactor of 75 gallon stainless steel (284 liters): 414.0 pounds (187.78 kg) of isooctyl acrylate (IOA), 5.0 grams of VazoMB 52 (2, 2'-azobis (2, 4-dimethylpentanitrile)), 208.7 grams of carbon tetrabromide, 1605.0 grams of a 26% by weight solids blend of 4-acryloxybenzophenone (ABP) in ethyl acetate, and 46.0 pounds (20.87 kg) of acrylic acid (AA). With the mixture maintained at 75 ° F (23.89 ° C), nitrogen was bubbled through the solution for 20 minutes to displace the oxygen from the mixture and the space in the upper part of the reactor (volume of the reactor not occupied by the mixture). of reaction). The reactor was pressurized to approximately 50 psig (448.16 kPa) with nitrogen and sealed. With the reactor agitator (a removable paddle stirrer, of 3 vanes) rotating at approximately 75 revolutions per minute, the temperature of the mixture was raised to 150 ° F (65.56 C) by circulating water at a controlled temperature through the reactor jacket. Once the polymerization began, the temperature control system was set to cause the temperature of the water circulating through the jacket to reach 10 ° F (5.56 ° C) above the batch temperature to facilitate the conditions of Adiabatic reaction. At about 3 minutes in reaction, as a final oxygen purge, the reactor pressure was vented at 5 psig (137.89 kPa) and then pressurized again to approximately 50 psig (448.16 kPa) with nitrogen. As shown in Figure 2, after approximately 10 minutes in the reaction, the batch temperature reached approximately 286 ° F (141.11 ° C) and the jacket temperature control system was unable to maintain the rate of increase of the batch. batch temperature. At this point the shirt was drained and the reaction temperature continued to rise. Seven minutes later, the reaction temperature reached 298 ° F (147.78 ° C) at which time cooling was applied to the reactor jacket. A sample of the reaction mixture was taken. The IV of the polymer was 0.51 dl / gm and the unreacted IOA in the mixture was 61% by weight based on the total weight of the mixture.

Once the batch temperature was low at 125 ° F (51.67 ° C), the nitrogen pressure in the reactor was ventilated. Then, using external steam ejectors, the pressure in the space of the upper part of the reactor (vacuum removed from the top of the reactor) was reduced to an absolute pressure (as opposed to the gauge pressure) of approximately 7.5 psi (51.71). kPa) and the reactor was sealed. The mixture was then charged under vacuum to the reaction mixture (suctioned in the reactor) through a deep tube in the reaction mixture: 10.0 grams of VazoMR 52 (2,2'-azobis (2-4) were dissolved. dimethylpentanitrile)), 6 grams of VazoMR 88 (2, 2'-azobis (cyclohexanecarbonitrile)), 10.0 grams of di-t-amyl peroxide, 30.0 grams of carbon tetrabromide, in 5 pounds (2.27 kg) of IOA. As a washing of the load line, 5 pounds (2.27 kg) more of IOA was vacuum loaded to the reaction mixture through the deep tube. The reactor temperature control system was calibrated to raise the batch temperature to 150 ° F (65.56 ° C). While the batch was heating to 150 ° F (65.56 ° C), with the stirring equipment at approximately 75 revolutions per minute, the reaction mixture was purged of oxygen using the following procedure: the vacuum was removed over the upper space of the reactor to cause a vigorous bubbling of the reaction mixture caused by trapped nitrogen from the first reaction cycle that must be released from the mixture for about 30 seconds. Thereafter the reactor pressure was raised to approximately 3 psig (124.11 kPa) with nitrogen and was maintained so for about 1 minute. Vacuum was again drawn to cause trapped nitrogen to degas the reaction mixture for about 30 seconds. Next, the space in the upper part of the reactor was pressurized to 5 psig (448.16 kPa) and remained so for about 1 minute. The reactor pressure was vented at approximately 3 psig (124.11 kPa) and was maintained so for approximately 1 minute. Finally, the reactor pressure was raised to 50 psig (448.16 kPa) with nitrogen and the reactor was sealed. Once the mixture reached 150 ° F (65.56 ° C), and the polymerization started, the temperature control system was calibrated to cause the temperature of the water circulating through the jacket to reach 10 ° F (5.56 ° C) ) above the batch temperature to facilitate adiabatic reaction conditions. The temperature of the batch was raised over a period of about one hour as shown in Figure 2. Once the batch temperature reached a peak at approximately 328 ° F (164.44 ° C), the jacket was drained and steam was applied at a pressure of approximately 110 psig (861.84 kPa) to the jacket to maintain the reaction mixture at approximately 330 ° F (165.56 ° C) for approximately 40 more minutes (the temperature of the jacket passed the point where it applied direct steam which it is not shown in Figure 2 because the temperature probe was not properly placed in the jacket pipe to measure the temperature of the jacket when direct steam is used). At this point, 208.7 grams of thermal stabilizer / antioxidant Irganox ™ 1010 (tetracis (methylene (3,5-di-tert-buty-4-hydroxyhydrocinnamate)) -methane), manufactured by Ciba-Geigy Corporation, dissolved in 400 was charged. grams of ethyl acetate through a deep tube in the reaction mixture. Next, a line wash load of 200 grams plus ethyl acetate was charged to the reaction mixture through the deep tube. The pressure in the upper space of the reactor was vented at approximately 5 psig (137.89 kPa). The batch was mixed at 330 ° F (165.56 ° C) with an agitation of about 75 revolutions per minute for approximately 12 hours. Then, residual unreacted monomer and residual ethyl acetate were removed from the reaction mixture under reduced vacuum at 330-340 ° F (165.56-171.11 ° C). The external vapors were condensed in an external heat exchanger. At this point, the Brookfield viscosity of the polymer product (measured at 180 ° C) was about 60,000 centipoise.

The product easily drained from the reactor with a slight nitrogen pressure at the top. The resulting polymer product had the following properties: unreacted IOA: 2.1% by weight based on the total weight of the mixture AA unreacted: 0.2% by weight based on the total weight of the IV mixture: 0.61 dl / gm Mn: 15,000 Mw: 270,000 Mw / Mn: 18 To test the adhesive properties of the polymeric product, adhesion and cut tests were conducted with the adhesive coated product (25 micron dry coating thickness). The adhesive coating was very uniform, with a finish similar to glass, free of any visible polymer gel particles. The adhesive was subsequently cured by exposure to ultraviolet radiation. Three different levels of UV radiation were used to cure the adhesive as shown in Table 2. A control was also included, without any subsequent cure in the results of Table 2.

TABLE 2 EXAMPLE 2 This example illustrates the use of the process of the invention to produce a hot melt acrylate pressure sensitive adhesive (ratio of isooctyl acrylate monomer / acrylic acid: 93/7). Two essentially adiabatic reaction cycles were used without vacuum separation of the residual unreacted monomer. The following components were charged to the same batch reactor of 75 gallon stainless steel (284 liters) used for Example 1: 427.8 pounds (194.05 kg) of isooctyl acrylate (IOA), 5.0 grams of VazoMR 52 (2.2 ') - azobis (2,4-dimethylpentanitrile)), 80.0 grams of isooctyl thioglycolate, 1605.0 grams of a 26% by weight solids blend of 4-acryloxybenzophenone (ABP) in ethyl acetate, and 32.2 pounds (14.61 kg) of acrylic acid (AA). The reaction mixture was purged from the oxygen and the polymerization reaction started in a manner similar to that of Example 1. The reaction started at 150 ° F (65.56 ° C) and after about 15 minutes of reaction time, with the temperature of the water from the jacket similar to the batch temperature in a manner similar to Example 1, the peak temperature of the batch obtained was 197 ° F (147.22 ° C). A sample of the reaction mixture was taken. The IV of the polymer was 0.62 dl / gm and the unreacted IOA in the mixture was 47% by weight based on the total weight of the mixture. As a correction in the process for adjusting the polymer solids down to about 50% by weight, 25.9 pounds of isooctyl acrylate and 1.9 pounds of acrylic acid were added to the batch. The reaction mixture was cooled in a manner similar to Example 1. Once the batch temperature reached approximately 130 ° F (54.44 ° C), the following components were charged to the batch: 10.0 grams of VazoMR 52 (2.2'- azobis (2, -dimethylpentannitrile)), 6.0 qramos of VazoMK 88 (2, 2'-azobis (cyclohexanecarbonitrile)), and 12.0 grams of di-t-amyl peroxide, 20.0 grams of isooctyl thioglycolate and in 10.0 pounds (4.54 kg) of isooctyl acrylate.

The mixture was stirred at approximately 100 revolutions per minute while heating to 150 ° F (65.56 ° C). The batch was purged from oxygen in a manner similar to the method used in Example 1 in this stage of the process. The space in the upper part of the reactor was pressurized to approximately 50 psig (448.16 kPa) with nitrogen for the reaction. The reaction procedure was the same as in Example 1: the reaction started at 150 ° F (65.56 ° C) and 30 minutes after the reaction time, with the water temperature of the jacket following the temperature of the batch so similar to Example 1, the peak temperature of the batch obtained was about 340 ° F (171.11 ° C). after stirring the batch for about two hours at approximately 340 ° F (171.11 ° C), 208.7 grams of IrganoxM 1010 (tetracis (methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate)) methane was added), dissolved in 400 grams of ethyl acetate to the batch in a manner similar to Example 1. Subsequently a line wash of 200 grams of ethyl acetate was added to the batch. The mixture was then stirred at about 80 revolutions per minute for about 4 hours at about 340-350 ° F (171. ll-176.67 ° C). No unreacted residual monomer was separated from the batch, as was the case in Example 1. The product easily drained from the reactor through a 16 mesh screen with a nitrogen pressure of 10 psig (172.37 kPa) over the space of the upper part of the reactor. The resulting drained product had the following properties: Unreacted IOA: 0.4% by weight based on the total weight of the unreacted AA mixture: 0.1% by weight based on the total weight of the IV mixture: 0.69 dl / gm Mn: 10,300 Mw: 312,300 M "/ Mn: 30 To test the adhesive properties of the polymeric product, adhesion and cut tests were conducted with the adhesive coated product (25 micron dry coating thickness). The adhesive coating was very uniform, with a finish similar to glass, free of any visible polymer gel particles. The adhesive was subsequently cured by exposure to ultraviolet radiation. Two different levels of UV radiation were used to cure the adhesive as shown in Table 3. A control was also included, without any subsequent cure in the results of Table 3.

TABLE 3 EXAMPLE 3 This example illustrates the use of the process of the invention to produce a hot melt acrylate pressure sensitive adhesive (ratio of isooctyl acrylate monomer / acrylic acid: 90/10). Five essentially adiabatic reaction cycles were used in combination with a vacuum extraction of the monomer without ± 3 react, residual, after completing the reaction cycles. The following components were charged to the same batch reactor of 75 gallon stainless steel (284 liters) used for Example 1: 360.0 pounds (163.29 kg) '? of isooctyl acrylate (IOA), 4.5 grams of VazoMR 52 (2,2'-azobis (2, -dimethylpentannitrile)), 181.4 grams of carbon tetrabromide, 1047.0 grams of a 26% solids blend of 4-acryloxybenzophenone ( ABP) in ethyl acetate, and 40 pounds (18.14 kg) of acrylic acid (AA). The The reaction mixture was purged from the oxygen and the polymerization reaction started in a manner similar to that of Example 1. The reaction started at 150 ° F (65.56 ° C) and after approximately 12 minutes reaction time, with the temperature of the jacket water following the batch temperature in a manner similar to Example 1, the peak temperature of the batch obtained was 287 ° F (141.67 ° C). A sample of the reaction mixture was taken. The IV of the polymer was 0.54 dl / gm and the unreacted IOA in the mixture was 63% by weight based on the total weight of the mixture. The reaction mixture was cooled in a manner similar to Example 1. Once the batch temperature reached approximately 120 ° F (48.89 ° C), the following components were charged to the batch: 10.0 grams of VazoMfi 52 (2.2'- azobis (2,4-dimethylpentanitrile)), 3.0 grams of VazoMR 88 (2, 2'-azobis (cyclohexanecarbonitrile)), and 14.0 grams of dicumyl peroxide, 10.0 grams of carbon tetrabromide, 40. 0 pounds (18.14 kg) of isooctyl acrylate, 4.4 pounds (2.00 kg) of acrylic acid and in 116.2 grams of a 26% by weight mixture of 4-acryloxy benzophenone (ABP) solids in ethyl acetate. The mixture was stirred at approximately 100 revolutions per minute while heating to 150 ° F (65.56 ° C). The batch was purged of oxygen by pressurizing at approximately 50 psig (448.16 kPa) and venting at approximately 2 psig (117.21 kPa) three times. The space in the upper part of the reactor was pressurized to approximately 50 psig (448. Hi kPa) with nitrogen for the reaction and sealed. EJ. The procedure of the reaction was the same as in Example 1: the reaction started at 150 ° F (65.56 ° C) and after about 3 minutes of reaction time, with the water temperature of the jacket following the temperature of the batch of Similar to Example 1, the peak temperature of the batch obtained was approximately 323 ° F (161.67 ° C). After a 30 minute retention period while mixing the batch at approximately 320 ° F (160.00 ° C), a sample of the reaction mixture was taken. The IV of the polymer was 0.59 dl / gm and the unreacted IOA in the mixture was 19.5% by weight based on the total weight of the mixture. Fifty minutes after taking the above sample, a mixture of 8.0 grams of di-t-amyl peroxide dissolved in 400.0 grams of ethyl acetate in the batch followed by a line rinse of 200.0 grams of ethyl acetate was pressurized. The batch was deoxygenated by venting at approximately 20-30 psig (241.31-310.26 kPa) and pressurizing to approximately 50 psig (448.16 kPa) with nitrogen twice. The reactor was pressurized to approximately 50 psig (448.16 kPa) and sealed to continue polymerization.

During the continuation of the reaction, the batch temperature rose from about 323 ° F (161.67 ° C) to about 336 ° F (16T.89 ° C). After one hour, a sample of the reaction mixture was taken. The IV of the polymer was 0.58 and the unreacted IOA in the mixture was 12.2% by weight based on the total weight of the mixture. Fifty minutes after taking the above sample, a mixture of 10.0 grams of di-t-amyl peroxide dissolved in 400.0 grams of ethyl acetate in the batch followed by a line wash of 200.0 grams of ethyl acetate was pressurized. The batch was deoxygenated by venting at approximately 20-30 psig (241.31-310.26 kPa) and pressurizing to approximately 50 psig (448.16 kPa) twice with nitrogen. The reactor was pressurized to approximately 50 psig (448.16 kPa) and sealed to continue polymerization. The batch temperature remained at approximately 335 ° F (168.33 ° C) during this reaction cycle. Forty minutes after adding the 10.0 gram starter charge above, a mixture of 6.0 grams of di-t-amyl peroxide dissolved in 400.0 grams of ethyl acetate in the batch was pressurized followed by a line wash of 200.0 grams of ethyl acetate. The batch was deoxygenated by venting at approximately 20-30 psig (241.31-310.26 kPa) and pressurizing to approximately 50 psig (448.16 kPa) twice with nitrogen. The reactor was pressurized to approximately 50 psig (448.16 kPa) and sealed to continue polymerization. The batch temperature remained at approximately 335 ° F (168.33 ° C) during this reaction cycle. One hour later, a sample of the reaction mixture was taken. The unreacted IOA in the mixture was 6.3% by weight based on the total weight of the mixture. After two more hours, 201.6 grams of Irganox1 * 1010 (tetracis (methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate) methane), dissolved in 400 grams of ethyl acetate were added to the batch in a similar manner to Example 1. A line wash of 200 grams of ethyl acetate was then added to the batch.The batch was mixed at approximately 320 ° F (160.00C, C) with an agitation of about 50-60 revolutions per minute. , a sample of the reaction mixture was taken in. The unreacted IOA in the mixture was 4.4% by weight based on the total weight of the mixture.The unreacted residual monomer and the residual ethyl acetate were then separated from the reaction mixture under reduced vacuum at 310 ° F (154.44 ° C) .The vapors were condensed in an external heat exchanger.

The resulting product easily drained from the reactor with a slight nitrogen pressure on top. The drained product had the following properties: unreacted IOA: 2.8% by weight based on the total weight of the unreacted AA mixture: 0.3% by weight based on the total weight of the IV mixture: 0.56 dl / gm Mn: 17,900 MW : 284,000 Mw / M ": 16 To test the adhesive properties of the polymeric product, adhesion and cutting tests were conducted with the coated product with adhesive (25 micron dry coating thickness). The adhesive coating was very uniform, with a finish similar to glass, free of any visible polymer gel particles. The adhesive was subsequently cured by exposure to ultraviolet radiation. Two different levels of UV radiation were used to cure the adhesive as shown in Table 4. A control was also included, without any subsequent cure in the results of Table 4.

TABLE 4 EXAMPLE 4 This example illustrates the use of the procedure of the The invention for producing a hot melt acrylate pressure-sensitive adhesive (ratio of isooctyl acrylate monomer / acrylic acid: 90/10). An essentially adiabatic reaction cycle was used to produce a polymer syrup which was separated from the monomer without react to produce a hot-melt acrylate pressure-sensitive adhesive. The following components were charged to the same batch reactor of 75 gallon stainless steel (284 liters) used for Example 1: 414.0 pounds (187.79 kg) isooctyl acrylate (IOA), 5.0 grams of VazoMR 52 (2,2'-azobis (2, -dimethylpentannitrile)), 135.0 grams of isooctyl thioglycolate, 1605.0 grams of a 26% by weight mixture of solids of 4 -acyloxybenzophenone (ABP) in ethyl acetate, and 46.0 pounds (20.87 kg) of acrylic acid (AA). The '2b reaction mixture was purged from the oxygen and the polymerization reaction started in a manner similar to that of Example 1. The reaction started at 150 ° F (65.56 ° C) and after approximately 12 minutes of reaction time, with the temperature of the jacket water following the batch temperature in a manner similar to Example 1, the peak temperature of the batch obtained was 293 ° F (145.00 ° C). the properties of the resulting polymer product were analyzed and found to be: Polymer solids: 41.9% by weight based on the total weight of the mixture (from the measurement of solids) Viscosity @ 2 ^ 0: approximately 30,000 centipoise (viscosity from Brookfield) IV: 0.62 dl / gm Mr ?: 104,000 Mw: 375,000 Mw / Mn: 3.6 At this point in the process, the monomer can be separated from the polymer using techniques and equipment known to those skilled in the art. To test the adhesive properties of the polymer, a 42.9% by weight solids polymeric syrup was coated with a knife at a dry coating thickness of 23.75 microns using the methods described above. The adhesive coating was very uniform, with a finish similar to glass, free of any visible polymer gel particles. The adhesive was subsequently cured by exposure to ultraviolet radiation. Two different levels of UV radiation were used to cure the adhesive to test the adhesive properties as shown in Table 5. A control, without any subsequent curing, was also included in the results of Table 5.

TABLE 5 EXAMPLE 5 A Reactive System Selection Tool (RSST) was used to effect the polymerization reactions for this example and several subsequent examples. The RSST is a small calorimeter available from Fauske and Associates, Inc. of Burr Ridge, Illinois, in which samples of approximately 10.0 ml can be reacted very close to the adiabatic conditions, apart from a constant, small heat feed, the which increases the temperature of the sample in the test cell a minimum of 0.25 ° C / min. It has been found that in the heating of non-reactive samples, the temperature control of the RSST does not work very well to maintain the desired heat rates or percentages-the heater automatically increases its power to counteract the heat losses to the surroundings and the Desired heat velocity is closely followed. However, in the practice of the present invention, when a sample is heated and begins to react exothermically, the heating does not increase its power exactly to counteract the heat losses when the temperature of the sample increases, particularly for reactions which begin quickly and gradually decrease at high temperatures. The power of the heater slightly delays the heat losses to the surroundings, which increase in proportion to the temperature of the material in the test cell. For example, when a polymerization is conducted in the RSST and the heater is set at its minimum heating rate of 0.25 ° C / min, when the polymerization ends due to the depletion of the initiator, the temperature of the cell stops increasing momentarily, with frequency cooling slightly a few ° C, until the power of the heater is increased by the temperature control program of the RSST to continue eventually heating the non-reactive sample to 0.25 ° C / min. subsequently, to keep the reaction conditions as close as possible to the adiabatic conditions, the heater is set or calibrated in the range of 0.25 ° C / min to 0.5 ° C / min at reaction temperatures above 135 ° C to increase the input power of the heater to more accurately counteract the heat losses during the reaction to facilitate adiabatic polymerization. The higher the heating rate, the faster the reactions. This procedure of the heating program with the RSST has been verified by comparing the temperature profiles of the polymerizations with RSST and the polymerizations of 75 gallons, where the water temperature of the reactor jacket is very close to the temperature of the batch. The particular version of the RSST used for the examples here contains a double bottom heater and a stainless steel cladding thermocouple for temperature measurements. This example illustrates the use of the process of the invention for producing a hot-melt acrylate pressure-sensitive adhesive (ratio of isooctyl acrylate monomer / acrylate / acrylic acid monomer: 75/20/5). Two essentially adiabatic reaction cycles were used without vacuum separation of the unreacted residual monomer. The following mixture was charged to the RSST test cell: 5.92 grams of isooctyl acrylate, 0.40 grams of acrylic acid, 1.62 grams of methyl acrylate, 0.10 grams of isooctyl thioglycolate, 0.092 grams of a 26% blend in Weight of solids of 4-acryloxybenzophenone (ABP) in ethyl acetate and 0.08 grams of 0.20 grams of VazoMR 52 (2, 2'-azobis (2,4-dimethylpentanenitrile)), dissolved in 100 grams of isooctyl acrylate. Once the RSST test cell was loaded with the reaction mixture, it was sealed in the containment container of the RSST. With stirring with a magnetic stirrer, the reaction mixture was de-oxygenated by pressurizing the containment vessel to approximately 300 psig (2171.84 kPa) with nitrogen, thus maintaining for about one minute, venting at about 5 psig (137.89 kPa), and thus maintaining approximately one minute. The pressurization and ventilation were repeated a total of five times. The containment vessel of the RSST was then pressurized to approximately 100 psig (792.89 kPa) with nitrogen to suppress the boiling of the unreacted monomers when the reaction temperature was increased.

The heater of the RSST was programmed to automatically increase the temperature of the test cell from room temperature to 55 ° C to 1 ° C / min and then heated to 0.25 ° C / min. Polymerization started at about 60 ° C (indicated by a gradual increase in the rate of temperature increase) and over a period of about 27 minutes, the temperature increased up to and reached a peak at about 160 ° C. At this point, the heater of the RSST was turned off and the sample was cooled to approximately 30 ° C. The reaction product of the first reaction cycle was mixed with 1.40 grams of isooctyl acrylate, 0.10 grams of acrylic acid, 0.40 grams of methyl acrylate, 0.023 grams of a 26% by weight mixture of 4-acryloxybenzophenone solids (ABP) in ethyl acetate and 0.10 of the following mixture: 100.0 grams of isooctyl acrylate, 0.38 grams of VazoMR 52 (2, 2'-azobis (2, -dimethylpentannitrile)), 0.28 of VazoMR 88 (2,2'-azobis (cyclohexanecarbonitrile)), 0.05 grams of di-t-apyloyl peroxide, 0.15 grams of t-amyl hydroperoxide. The test cell was placed in the containment vessel of the RSST again and deoxygenated using the same procedure as for the first reaction cycle and pressurized to approximately 100 psig (792.89 kPa) for the reaction.

For this reaction cycle the RSST was adjusted to automatically increase the temperature of the test cell to 55 ° C to 1 ° C / min, up to 60 ° C 0. 5 ° C / min, up to 135 ° C at 0.25 ° C / min, up to 180 ° C / min at 0.5 ° C per minute, and finally up to 185 ° C at 0.25 ° C / min. .When the reaction mixture heated up, when I reached approximately 65 ° C polymerization began. 90 minutes later the reaction temperature reached a peak at about 165 ° C. At this point the adiabatic reaction conditions were abandoned, and by the preprogrammed temperature profile described above, the sample continued to be heated to 185 ° C and maintained at this temperature for 360 minutes The properties of the resulting polymer were analyzed and found to be: Polymer solids: 96.0% by weight based on the total weight of the mixture (from the measurement of solids) IV: 0.52 dl / gm Mn: 13,900 M ": 222,200 To test the adhesive properties of the polymeric product, adhesion and cut tests were conducted with the adhesive coated product (25 micron dry coating thickness). The adhesive coating was very uniform, with a finish similar to glass, free of any visible polymer gel particles. The adhesive was subsequently cured by exposure to ultraviolet radiation. Two different levels of UV radiation were used to cure the adhesive as shown in Table 6. A control was also included, without any subsequent cure in the results of Table 6. 0 TABLE 6 fifteen EXAMPLE 6 This example illustrates the use of the process of the invention to produce a pressure sensitive adhesive, of 'í?' acrylate, by hot melt. The use of a methacrylate-terminated styrene macromonomer was demonstrated as one of the monomers being polymerized, eliminating the need for subsequent curing of the adhesive to give internal resistance to the adhesive (monomer ratio of isooctyl acrylate / styrene macromonomer / acrylic acid: 87/6/7). The following mixture was added to the RSST test cell: 8.88 grams of the following mixture: 79.06 grams of isooctyl acrylate, 7.00 grams of acrylic acid, 0.127 grams of isooctyl thioglycolate, and 2.50 grams of a 0.05 gram solution of Vazo ™ 52 (2, 2'-azobis (2,4-dimethylpentanenitrile)) dissolved in 90.0 grams of isooctyl acrylate. Also added were 1.14 grams of a 52.5% by weight solution of a methacrylate-terminated styrene macromonomer, dissolved in isooctyl acrylate, to the test cell. The methacrylate-terminated styrene macromonomer had a weight average molecular weight of about 10, 000, a polydispersity capacity of about 1.0, and was prepared in the manner described in Example M-1 of US Pat. No. 4,732,808. Once the RSST test cell was loaded with the reaction mixture, it was sealed in the containment container of the RSST. With the stirring of a magnetic stirrer, the reaction mixture was deoxygenated by pressurizing the containment vessel to approximately 300 psig (2171.84 kPa) with nitrogen, thus maintaining for about one minute, venting at about 5 psig (137.89 kPa), and thus maintaining for about a minute. The pressurization and ventilation were repeated a total of five times. Then the containment vessel of the RSST was pressurized to approximately 100 psig (792.89 kPa) with nitrogen to suppress the boiling of the unreacted monomers when the reaction temperature was increased. The RSST was calibrated to gradually increase the temperature of the test cell from room temperature to 55 ° C to 1.0 ° C / min and then the temperature was gradually increased to 0.25 ° C / min after passing 55 ° C . Polymerization started at about 64 ° C and for a period of about 23 minutes, the temperature increased until it reached a peak at about 133 ° C. The heater of the RSST was then turned off and the sample was cooled to approximately 30 ° C. The product of the reaction of the first reaction cycle was mixed with 0.10 grams of the following mixture: 100. 0 grams isooctyl acrylate, 0.4792 grams VazoMR 52 (2, 2'-azobis (2, -dimethylpentannitrile)), 0.2815 of VazoMR 88 (2, 2'-azobis (cyclohexanecarbonitrile)), and 0.1220 grams of di-t-amyl peroxide. The test cell was placed in the containment vessel of the RSST again and deoxygenated using the same procedure as for the first reaction cycle and pressurized to approximately 50 psig (448.16 kPa) for the reaction. The RRST was graduated to automatically increase the temperature of the test cell to 55 ° C to 50 ° C / min, up to 60 ° C to 0.5 ° C / min, and up to 0.25 ° C beyond 60.0 ° C. . As the reaction mixture was heated, when it reached about 65 ° C, the polymerization began. After approximately 133 minutes the reaction temperature reached a peak at 160 ° C. It was found that the polymer product had an IV value of 0.53 dl / gm. To test the adhesive properties of the polymeric product, adhesion and cut tests were conducted with the adhesive coated product (dry coating thickness of 21 microns). The adhesive coating was very uniform, with a finish similar to glass, free of any visible polymer gel particles. The adhesive was not subsequently cured by exposure to ultraviolet radiation. The adhesive properties obtained were an adhesion of 60.7 N / 100 nm and a cut-off value of 1577 minutes. Compared with the other adhesive samples prepared in the examples presented here, this cut-off value is much higher than that of other control samples cured with non-ultraviolet radiation.

EXAMPLE 7 This example illustrates the application of the process of the invention to produce a polymer using octadecyl acrylate / isooctyl acrylate / N, N-dimethyl acrylamide with a monomer ratio of: 50 / 14.3 / 35.7. The following components were charged to a batch reactor of 10 gallon stainless steel (37.9 liters): 17. 7 pounds (8.03 kg) of octadecyl acrylate, 5.1 pounds (2.31 kg) of isooctyl acrylate, 12.7 pounds (5.76 kg) of N, N-dimethyl acrylamide, 0.47 grams of VazoMR 52 (2,2'-azobis (2, -dimethylpentannitrile)), and 79.4 grams of 3-mercapto-1,2-propanediol. The reaction mixture was purged of oxygen by bubbling nitrogen through the reaction mixture for 20 minutes with the anchor-type stirrer, 2 blades of the reactor stirring at about 75 revolutions per minute. The space in the upper part of the reactor was then pressurized to 50 psig (448.16 kPa) with nitrogen and sealed for the reaction. The batch was heated to 140 ° F (60 ° C) and when the reaction started, the temperature of the water in the reactor jacket was set so as to closely follow the batch temperature. 27 minutes after the reaction, the batch temperature reached a peak at 276 ° F (135.5 ° C). The batch was then cooled to 125 ° F (51.7 ° C). Then, after purging the nitrogen pressure, the following components were added to the reactor: 1.08 grams of VazoMR 52 (2, 2'-azobis (2,4-dimethylpentanenitrile)), 0.60 grams of VazoMR 88 (2.2 '). -azobis (cyclohexanecarbonitrile)), 0.51 grams of di-t-amyl peroxide, 100.0 grams of octadecyl acrylate, 28.6 grams of isooctyl acrylate, and 71.4 grams of N, N-dimethyl acrylamide. Next, to purge the oxygen from the reaction mixture, a slight vacuum was drawn from the upper space of the reactor to cause the trapped nitrogen to bubble in the reaction mixture for about 20 seconds. The batch was then pressurized to approximately 2 psig (117.21 kPa). Again a slight vacuum was drawn from the top of the reactor to cause the entrapped nitrogen to bubble from the reaction mixture for about 20 seconds. Finally, the space in the upper part of the reactor was pressurized to approximately 50 psig (448.16 kPa). The reaction mixture was then heated to 150 ° F (65.56 ° C) and when the reaction started, the temperature of the water in the reactor jacket was set to closely monitor the temperature of the batch. After 55 minutes of reaction, the batch temperature reached a peak at 294 ° F (145.5 ° C). The reaction mixture was maintained at approximately 280 ° F-290 ° F (137.8 ° C-143.3 ° C for the next four hours.) The polymeric product, at approximately 270 ° F (132.2 ° C), drained easily through a wire screen. 40 mesh without breaking the continuity of operation in the reactor essentially The properties of the resulting polymer were analyzed and found to be: Polymer solids: 98.9% by weight based on the total weight of the mixture (from the measurement of solids ) M ": 16, 300 Mw: 43, 600 Mw / Mn: 2. 81 EXAMPLE 8 This example illustrates the application of the process of the invention to produce a polymer using octadecyl acrylate / ethyl acrylate < / methyl methacrylate with a monomer ratio of: 30 / 33.4 / 36.6. 10.0 grams of the following mixture was loaded into an RSST test cell: 30% octadecyl acrylic, 33.4% ethyl acrylate and 36.6% ethyl methacrylate (all based on one percent by weight). Also, 0.05 grams of 3-mercapto-l, 2-propandiol and 0.10 grams of a mixture of 0.3 grams of VazoMR 52 (2,2'-azobis (2,4-dimethylpentannitrile)) v 0.3 grams were charged to the test cell. of Vazo ™ 67 (2,2'-azobis (cyclohexanecarbonitrile)) dissolved in 25.0 grams of methyl methacrylate.

Once the RSST test cell was loaded with the reaction mixture, it was sealed in the containment container of the RSST. With the stirring of a magnetic stirrer, the reaction mixture was deoxygenated by pressurizing the containment vessel to approximately 300 psig (2171.84 kPa) with nitrogen, thus maintaining for about one minute, venting or venting at approximately 5 psig (137.89 kPa), and Keeping like that for about a minute. The pressurization and ventilation or purge were repeated a total of five times. The containment vessel of the RSST was then pressurized to approximately 50 psig (448.16 kPa) with nitrogen to suppress boiling of the unreacted monomers when the reaction temperature was increased. The RSST was calibrated to gradually increase the temperature of the test cell to 55 ° C at 1.0 ° C / min and then the temperature was gradually increased to 0.35 ° C / min above 55 ° C. The polymerization started at about 65 ° C and for a period of about 49 minutes, the temperature increased up to and reached a peak at about 149 ° C. The heater of the RSST was turned off and the sample was cooled to approximately 30 ° C. Next, 0.10 grams of the following mixture was mixed in the reaction product the first reaction cycle: 0.30 grams VazoMR 52 (2, 2'-azobis (2,4-dimethylpentannitrile)), 0.3 grams of VazoMR 67 (2, 2'-azobis (2-methylbutannitrile)), and 0.3 grams of VazoMR 88 (2,2'-azobis (cyclohexanecarbonitrile)) dissolved in 25.0 of methyl methacrylate. The test cell was ed in the containment vessel of the RSST again and deoxygenated using the same procedure as for the first reaction cycle and pressurized to approximately 50 psig (448.16 kPa) for the reaction. The RRST was programmed to gradually increase the temperature of the test cell to 55 ° C to 1 ° C / min, and then gradually increase to 0.35 ° C to 140 ° C. When the reaction mixture was heated, when it reached about 74 ° C, the polymerization started. After about 30 minutes the reaction temperature reached a peak at 140 ° C. At this point the sample was maintained at 140 ° C for more than 180 minutes. The properties of the resulting polymer were analyzed and found to be: Polymer solids: 94.5% by weight based on the total weight of the mixture (from the solids measurement) Mr ?: 17.946 Mw: 43.390 Mw / Mn: 2.42 EXAMPLES 9, 10, 11 A series of polymerizations of methyl methacrylate (MMA) were performed in the Reactive System Selection Tool (RSST). In each case the test cell was charged with methyl methacrylate, n-octyl mercaptan, VazoMR 52 (2,2'-azobis (2,4-dimethylpentannitrile)), VazoMR 88 (2,2'-azobis (cyclohexanecarbonitrile)) , and di-t-amyl peroxide in the amounts shown in Table 7. Methyl methacrylate was used as delivered by ICI Acrylics, St. Louis, MO, with 100 ppm of MEHQ inhibitor (4-ethoxyphenol).

TABLE 7 Once the RSST test cell was loaded with the reaction mixture, it was sealed in the containment container of the RSST. With the stirring of a magnetic stirrer, the reaction mixture was deoxygenated by pressurizing the containment vessel to approximately 300 psig (2171.84 kPa) with nitrogen, holding for about one minute, venting or venting at approximately 5 psig (137.89 kPa), and holding for about one minute. The pressurization and ventilation or purge were repeated a total of five times. The containment vessel of the RSST was then pressurized with nitrogen to suppress the boiling of the unreacted MMA when the reaction temperature was increased. The RRST was pressurized to approximately 50 psig (448.16 kPa) for Examples 9 and 10 and pressurized to approximately 100 psig (792.89 kPa) for Example 11. The RSST was calibrated to gradually increase the temperature of the test cell of the ambient temperature up to 55 ° C at 1.0 ° C / min and then the temperature was gradually increased to 0.25 ° C / min above 55 ° C. The temperature of the reaction mixtures during heating and during polymerization is shown in Figure 3. In each case, once the rate of temperature increase decreased to approximately 0.25 ° C, the heater of the RSST was turned off. In each case, the polymerization reaction started at about 58-60 ° C (where the rate of temperature increase increased above 0.25 ° C / min).

The conversions determined from the solids measurements, GPC data and IV data for each experiment are presented in Table 8. The conversion values shown are percent by weight of the polymer in the final reaction mixture. Because the GPC was calibrated with poly (styrene) standards, the molecular weights shown in Table 8 are not absolute values.

TABLE 8 As shown in Table 8, the polydispersity values obtained are very low. In fact, they are close to the minimum value of 2.0 obtainable with MMA free radical polymerization (Ray WH "On the Mathematical Modeling of Polymerization Reactors", J. Macromol, Sci. Macromol. Chem, C8 (1), 1972). . A secondary standard of poly (methyl methacrylate) was measured for comparison. The secondary standard was from Scíific Polymer Products, Inc. Its Mw indicated in the sample container was 93,300 and its Mn indicated in the container was 46,400. The measured polydispersities of the examples were all smaller than the secondary standard which had a polydispersity of 2.01. It is known that the isothermal polymerization of MMA exhibits a self-acceleration of the polymerization rate with an accompanying increase in molecular weight and an expansion of the molecular weight distribution. This self-acceleration can become pronounced at a polymer content as low as 20% in the monomer for isothermal polymerization (Principles of Polymer Chemistry, P. Flory, Cornell University Press, 1953). Because molecular weight distributions were conserved at a polydispersity of about 2.0 with an increase in conversion, this indicates that the increasing temperature profile makes self-acceleration a negligible phenomenon, allowing a narrow molecular weight distribution to be achieved. Theoretically, polymerization by free radicals at a controlled temperature, in the absence of a significant gelling effect, must employ a decreasing temperature profile to minimize the expansion of the molecular weight distribution as the polymerization progresses (Sacks et al. , "Effect of Temperature Variations Molecular Weith Distributions: Batch, Chain Addition Polymerizations", Chem. Eng. Sci., 28, 241, 1973). A decreasing temperature profile could counteract the productivity in this case because the viscosity could increase in an unmanageable manner as the temperature decreases, particularly in combination with the increase in the polymer content of the reaction. Although this invention has been described in relation to specific embodiments, it should be understood that it is capable of being further modified. The claims of the present are intended to cover all those variations that one skilled in the art could recognize as chemical equivalents of what has been described herein.

It is noted that in relation to this date, the best method known to 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 (9)

1. A method of free radical polymerization of vinyl monomers, characterized in that it comprises the steps of: (a) providing a mixture comprising: (i) vinyl monomers (co) polymerizable by free radicals; (ii) optional chain transfer agent; (iii) optional crosslinking agent; (iv) at least one thermal free radical initiator; (v) optionally a polymer comprising polymerized free radical polymerizable monomers; in a batch reactor; (b) deoxygenating the mixture, wherein step (b) may at least overlap partially with step (c); (c) heating the mixture to a temperature sufficient to generate sufficient free radical initiator from at least one thermal free radical initiator to initiate the polymerization; (d) allowing the mixture to polymerize under essentially adiabatic conditions to give at least one partially polymerized mixture; (e) optionally heating the mixture to generate free radicals from some or all of any initiator that has not been generated by the free radical initiator, and then allowing the mixture to polymerize under essentially adiabatic conditions to give an even more polymerized mixture; and (f) optionally repeating step (e) one or more times.

2. A method of polymerization of vinyl monomers by free radicals, characterized in that it comprises the steps of: (a) providing a mixture comprising: (i) vinyl monomers (co) polymerizable by free radicals; (ii) optional chain transfer agent; (iii) optional crosslinking agent; (iv) at least one thermal free radical initiator; (v) optionally a polymer comprising polymerized free radical polymerizable monomers; in a batch reactor; (b) deoxygenating the mixture if the mixture is not already deoxygenated, wherein step (b) may optionally at least partially overlap with step (c); (c) heating the mixture to a temperature sufficient to generate sufficient free radical initiator from at least one thermal free radical initiator to initiate the polymerization; (d) allowing the mixture to polymerize under essentially adiabatic conditions to give at least one partially polymerized mixture; (e) optionally heating the mixture to generate free radicals from some or all of any initiator that has not been generated by the free radical initiator, and then allowing the mixture to polymerize under essentially adiabatic conditions to give an even more polymerized mixture; and (f) optionally repeating step (e) one or more times. (g) optionally cooling the mixture; (h) adding to the mixture in the batch reactor at least one thermal free radical initiator, wherein the initiators of step (h) may be the same as or different from the initiators of step (a), optionally radically polymerizable monomers free, optionally crosslinking agents, optionally chain transfer agents, optionally a polymer comprising polymerizable free radical polymerizable monomers, wherein the mixture optionally has a lower temperature than that which could generate initiating free radicals of the initiators added in the weight (h); (i) deoxygenate the mixture if the mixture is not already deoxygenated; (j) optionally heating the mixture to generate initiator free radicals from at least one initiator to further polymerize the mixture if the mixture has a lower temperature that could generate initiating free radicals from the initiators added in step (h); (k) allowing the mixture to polymerize further under essentially adiabatic conditions to give an even more polymerized mixture; (1) optionally heating the mixture to generate free radicals from some or all of any initiator that does not generate initiating free radicals, and then allowing the mixture to polymerize under essentially adiabatic conditions to give an even more polymerized mixture; (m) optionally repeating step (1) one or more times; (n) optionally repeating steps (g) through (m) one or more times.

3. The method according to claim 1 or 2 characterized in that the free radical polymerizable monomer is selected from the group consisting of isooctyl acrylate, isononyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, dodecyl acrylate, n-acrylate, -butyl, hexyl acrylate, octadecyl acrylate, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, N-butyl methacrylate, N-vinyl pyrrolidone, N, N-dimethyl acrylamide, acrylic acid and mixtures of the same.

4. The method according to claim 1 or 2 characterized in that the initiators are selected from the group consisting of organic peroxides, organic hydroperoxides, initiators of the azo group, and mixtures thereof.

5. The method according to claim 1 or 2 characterized in that more than one initiator is present in the mixture of step (a).

6. The method according to claim 2, characterized in that 1 to 5 different initiators are present in the mixture of step (a), 1 to 5 different initiators are present in step (h), and 1 to 5 initiators are present different in each repetition of steps (g) through (m) when step (n) is included.

7. The method according to claim 1 or 2 characterized in that when more than one initiator is included (dl \ in the mixture, and the value of "[" "! 'E - * - val ° r negative of the first derivative of the concentration of the initiator i with respect to time, by at least one initiator i in a series of n ordered primers of the lowest temperature at the highest temperature for each initiator i which produces a half-life of one hour where i = nl, n > 1, ei = l, ..., n, decreases to approximately 10% of its maximum value, the value of -I -] for the next initiator in the series increased to at least approximately 20% of its "" maximum value, as the reaction temperature increases due to essentially adiabatic polymerization, where n is the number of initiators and t is time.

8. The method according to claim 1 or 2 characterized in that when more than one initiator is used, and the value of the negative value of the first derivative of the concentration of the initiator i with respect to time, by at least one initiator i in a series of n initiators where i > 1, n > l, and where i = 1, ..., n, you reached approximately 30% of its maximum value, the previous initiator in the series of ordered initiators from the lowest temperature to the highest temperature for each initiator i that produces a life a dd "a praying has already reached: sreí 'di. maximum value of - | - ~]. when the reaction temperature increases due to essentially adiabatic polymerization where n is the number of initiators and t is time.

9. The method according to claim 1 or 2 characterized in that the polymerization is conducted under adiabatic conditions.