| PATENT ASSIGNEE'S COUNTRY | USA |
| UPDATE | 04.00 |
| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | 04.04.00 |
| PATENT TITLE |
High temperature polymerization process and products therefrom |
| PATENT ABSTRACT | High temperature polymerization process and products obtained therefrom are provided. The polymerization is conducted at above 225.degree. C. to produce polymers having a degree of polymerization below 50. The products are useful as detergent additives and for subsequent polymerization |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | 05.03.98 |
| PATENT REFERENCES CITED | Feit, B.A. Base-Catalysed Oligomerization of Vinyl Monomers-III, Europ. Polym. J., 8, pp. 321-328, 1972. |
| PATENT PARENT CASE TEXT | This data is not available for free |
| PATENT CLAIMS |
We claim: 1. An oligomer mixture, comprising: (a) from 5 to 95 percent by weight of the oligomer mixture of terminally unsaturated oligomers of the formula: ##STR5## wherein X.sub.1 and X.sub.2 are independently selected from the group consisting of H, NH.sub.4, alkali metals and alkaline earth metals; and wherein n is 1; (b) from 5 to 95 percent by weight of the oligomer mixture of terminally unsaturated oligomers of the formula: ##STR6## wherein X.sub.1 and X.sub.2 are independently selected from the group consisting of H, NH.sub.4, alkali metals and alkaline earth metals; and wherein n is 2; (c) from 5 to 90 percent by weight of the oligomer mixture of terminally unsaturated oligomers of the formula: ##STR7## wherein X.sub.1 and X.sub.2 are independently selected from the group consisting of H, NH.sub.4, alkali metals and alkaline earth metals; and wherein n is 3 to 10; and wherein the sum of (a), (b), and (c ) is equal to 100 percent, based on the total weight of the terminally unsaturated oligomers. |
| PATENT DESCRIPTION |
This invention relates to a high temperature polymerization process and products therefrom. In particular, this invention relates to a high temperature polymerization process to produce oligomers. More particularly, this invention relates to a high temperature polymerization process to produce terminally unsaturated oligomers. Oligomers, as used herein and in the appended claims, refers to polymers having degree of polymerization of below 50. Low molecular weight polymers are known to be useful detergent additives, anti-redeposition agents, hard surface cleaners, scale inhibitors, pigment dispersants, mineral dispersants, clay dispersants, water treatment additives and the like. However, production of very low molecular weight polymers of carboxylic monomers, especially acrylic acid, has proven to be a difficult task. In certain applications, such as detergent additives, it is becoming increasingly important that the carboxylic acid polymers are biodegradable. It is known that biodegradability increases as molecular weight decreases. Therefore, processes which produce very low molecular weight polymers may provide routes to biodegradable polymer products. The art has long sought an inexpensive, efficient and environmentally sound way to produce low molecular weight polymers. One method of achieving low molecular weight polymers is through the use of efficient chain transfer agents, but this approach has several drawbacks. This approach incorporates the structure of the chain transfer agent into the polymer chain. This can be undesirable since that structure will have an increasing effect on the properties of the polymer as molecular weight decreases. Furthermore, the chain transfer agents commonly employed are mercaptans. These materials are expensive and have objectionable odors associated with their presence. Other common chain transfer agents are hypophosphites, bisulfites and alcohols. These also add to the cost of the process, impart functionality to the polymer, can introduce salts into the product, and may necessitate a product separation step. Another way of lowering the molecular weight of the polymers produced is by increasing the amount of initiator. This approach adds considerably to the cost of production and may result in polymer chain degradation, crosslinking, and high levels of unreacted initiator remaining in the product. In addition, high levels of initiator may also result in high levels of salt by-products in the polymer mixture which is known to be detrimental to performance in many applications. The same is true for chain stopping agents such as sodium metabisulfite. Among the preferred free-radical initiators for aqueous polymerization is hydrogen peroxide. It is relatively inexpensive, has low toxicity, and does not produce detrimental salt by-products. However, hydrogen peroxide does not generally decompose efficiently at conventional polymerization temperatures and large amounts must normally be used to generate enough radicals to carry out a polymerization. High levels of metal ions together with high levels of initiator have also been tried as a means for controlling molecular weight. Such an approach is unsuitable for some products, such as water treatment polymers, which cannot tolerate metal ion contaminants in the polymer product. In addition, depending on the metal ions used, the product may be discolored due to the presence of the metal ions. In the European Polymer Journal, 1972, Vol. 8, pp. 321-328, Feit describes a multistep synthesis technique for preparing terminally unsaturated oligomers. The process described therein requires a base-catalyzed addition of an acetic acid ester derivative to an activated olefin, followed by hydrolysis of one ester group, followed by a Mannich reaction to introduce a terminal double bond. This three step process is repeated to prepare a terminally unsaturated oligomer with one additional mer. This process suffers the drawback of being fairly complex, expensive and time-consuming. The present invention seeks to overcome the problems associated with the previously known methods for preparing terminally unsaturated oligomers. In a first aspect of the present invention, there is provided a terminally unsaturated oligomer of the formula: ##STR1## wherein X.sub.1 and X.sub.2 are independently selected from the group consisting of H, NH.sub.4, alkali metals and alkaline earth metals; wherein M is the residue of a monoethylenically unsaturated monomer; wherein m is 0 to 47; wherein n is 2 to 50; and wherein the sum of n and m is less than or equal to 50. It is understood that the N and M residues in the terminally unsaturated oligomer may be randomly arranged. In other words, adjacent the terminally unsaturated moiety may be either an N or an M residue; the residue adjacent the residue adjacent the terminally unsaturated moiety may be either an N or an M residue, and so on. In a second aspect of the present invention, there is provided an oligomer mixture, comprising: (a) from 5 to 95 percent by weight of the oligomer mixture of terminally unsaturated oligomers of the formula: ##STR2## wherein X.sub.1 and X.sub.2 are independently selected from the group consisting of H, NH.sub.4, alkali metals and alkaline earth metals; wherein n is 1; (b) from 5 to 95 percent by weight of the oligomer mixture of terminally unsaturated oligomers of the formula: ##STR3## wherein X.sub.1 and X.sub.2 are independently selected from the group consisting of H, NH.sub.4, alkali metals and alkaline earth metals; wherein M is the residue of a monoethylenically unsaturated monomer; wherein m is 0 or 1; wherein n is 1 or 2; and wherein the sum of n and m is 2; and (c) from 0 to 90 percent by weight of the oligomer mixture of terminally unsaturated oligomers of the formula: ##STR4## wherein X.sub.1 and X.sub.2 are independently selected from the group consisting of H, NH4, alkali metals and alkaline earth metals; wherein M is the residue of a monoethylenically unsaturated monomer; wherein m is 0 to 5; wherein n is 3 to 10; wherein the sum of n and m is less than or equal to 10; and wherein the sum of (a), (b) and (c) is equal to 100 percent. In a third aspect of the present invention, there is provided a continuous process for preparing terminally unsaturated oligomers comprising: (a) forming a reaction mixture comprising (i) from 0.5 to 99.95 percent by weight of the reaction mixture of at least one monomer selected from the group consisting of acrylic acid and salts thereof, and acrylic acid and salts thereof in combination with at least one monoethylenically unsaturated monomer; (ii) from 0.05 to 25 percent by weight based on the weight of the at least one monomer of at least one free-radical initiator; and (iii) optionally, from 0 to 99.5 percent by weight of the reaction mixture of at least one solvent; (b) continuously passing the reaction mixture through a heated zone wherein the reaction mixture is maintained at a temperature of at least 225.degree. C. for from 0.1 seconds to 300 seconds to form terminally unsaturated oligomers. In a fourth aspect of the present invention, there is provided a polymer product comprising, as polymerized units, the terminally unsaturated oligomers of the present invention. In a fifth aspect of the present invention, there is provided a detergent composition comprising the terminally unsaturated oligomers of the present invention. In a sixth aspect of the present invention, there is provided a detergent composition comprising a polymer product comprising, as polymerized units, the terminally unsaturated oligomers of the present invention. The acrylic acid used in the process of the present invention can be glacial acrylic acid or a solution of acrylic acid. Furthermore, the acrylic acid can be in the form of a salt such as an alkali metal salt, ammonium salt, alkaline earth metal salt or a combination thereof. Preferably, the acrylic acid is glacial acrylic acid or an aqueous solution of acrylic acid. The acrylic acid is present in the reaction mixture at a level of from 0.5 to 99.95 percent by weight, preferably from 1 to 95 percent by weight, most preferably from 5 to 90 percent by weight. In addition to the acrylic acid, other monoethylenically unsaturated monomers may be used. Other suitable monoethylenically unsaturated monomers include other C.sub.3 -C.sub.6 monoethylenically unsaturated monocarboxylic acids, and the alkali metal, alkaline earth metal and ammonium salts thereof, such as, for example, methacrylic acid, crotonic acid, vinylacetic acid, and acryloxypropionic acid and salts thereof. Other suitable monoethylenically unsaturated monomers include C.sub.4 -C.sub.8 monoethylenically unsaturated dicarboxylic acids and the alkali metal and ammonium salts thereof, and the anhydrides of the cis-dicarboxylic acids; such as, for example, maleic acid, maleic anhydride, itaconic acid, mesaconic acid, fumaric acid, citraconic acid, tetrahydrophthalic anhydrides, cyclohexene dicarboxylic acids and salts thereof. Other suitable monoethylenically unsaturated monomers include acrylamide, t-butylacrylamide, N,N-dimethylacrylamide, and acrylonitrile. Other monoethylenically unsaturated monomers include alkyl esters of acrylic or methacrylic acids such as methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and isobutyl methacrylate; hydroxyalkyl esters of acrylic or methacrylic acids such as hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate; acrylamide, methacrylamide, N-tertiarybutylacrylamide, N-methylacrylamide, dimethylaminopropylmethacrylamide; methacrylonitrile, allyl alcohol, allylsulfonic acid, allylphosphonic acid, vinylphosphonic acid, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, phosphoethyl methacrylate, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, vinyl acetate, styrene, styrenesulfonic acid and its salts, vinylsulfonic acid and its salts, and 2-acrylamido-2-methylpropanesulfonic acid and its salts. When used, the other monoethylenically unsaturated monomers may be present in the reaction mixture at a level of from 0.05 to 99, preferably from 1 to 95, most preferably from 5 to 90. The monoethylenically unsaturated monomers which are acids may be in their acid forms or in the form of the alkali metal, alkaline earth metal or ammonium salts of the acid, or a combination thereof. Suitable bases useful for neutralizing the monomer acids include sodium hydroxide, ammonium hydroxide, and potassium hydroxide. The acid monomers may be neutralized to a level of from 0 to 100 percent. Most preferably, the carboxylic acid monomers are used in the unneutralized form, however, partial neutralization of the carboxylic acid monomers may alleviate corrosion on parts of the reaction equipment. The monomers may be neutralized prior to or during the oligomerization reaction. The terminally unsaturated oligomer products are often particularly useful in their partially or completely neutralized form. Partially neutralized terminally unsaturated oligomers, will have the formulae shown above, and in the claims below wherein X.sub.2 will be different among the mers of the terminally unsaturated oligomers. Suitable initiators for the processes of the present invention are any conventional free-radical initiators including, but are not limited to, hydrogen peroxide, certain alkyl hydroperoxides, dialkyl peroxides, peresters, percarbonates, persulfates, peracids, oxygen, ketone peroxides, azo initiators and combinations thereof. Specific examples of some suitable initiators include hydrogen peroxide, oxygen, t-butyl hydroperoxide, di-tertiary butyl peroxide, tertiary-amyl hydroperoxide, methylethyl ketone peroxide and combinations thereof. The initiators are normally used in amounts of from 0.05 percent to 25 percent based on the weight of total polymerizable monomer. A preferred range is from 0.5 to 20 percent by weight of the total polymerizable monomer. The monomers are preferably polymerized as dilute solutions. The reaction mixture may contain one or more solvents at a level of from 0 to 99.5 percent by weight of the reaction mixture, preferably from 30 to 97 percent by weight of the reaction mixture, and most preferably from 50 to 95 percent by weight of the reaction mixture. As the relative amount of one or more solvents in the reaction mixture decreases, particularly below 60 percent, the molecular weight and the polydispersity (D) of the resulting oligomer mixture increases. Suitable solvents for the process of the present invention are capable of dissolving the one or more monomers and the oligomers formed therefrom. Suitable solvents for the present invention include, for example, water, acetone, methanol, isopropanol, propionic acid, acetic acid, methylethyl ketone, dimethylformamide, dimethylsulfoxide and combinations thereof. Water is the preferred solvent. In the process of the present invention, the reaction mixture is continuously passed through a heated zone wherein the reaction mixture is maintained at a temperature of at least 225.degree. C. under elevated pressure. Once the reaction mixture is formed, it is preferable to have the passing reaction mixture reach the polymerization temperature as rapidly as possible. Preferably, the reaction mixture reaches the polymerization temperature within 5 minutes, more preferably within 2 minutes, most preferably within 1 minute. Prior to reaching the reaction temperature, the reaction mixture may be at any suitable temperature, preferably at a temperature of from room temperature to 450.degree. C., most preferably from a temperature of from 60.degree. C. to 400.degree. C. The oligomerization is conducted at a temperature of at least 225.degree. C., and is preferably conducted at a temperature in the range of from 250.degree. C. to 500.degree. C., and most preferably at a temperature in the range of from 275.degree. C. to 450.degree. C. At temperatures below 225.degree. C., the molecular weight of the oligomer increases and the relative amount of by-products, particularly non-terminally unsaturated compounds, increases. The oligomerization at these elevated temperatures is rapid. Thus, the reaction mixture can be maintained at the polymerization temperature for as little as 0.1 seconds, preferably from 0.5 seconds to 5 minutes, most preferably from 1 second to 2 minutes. At extended periods of time at which the reaction mixture is exposed to the polymerization temperature, the yield of terminally unsaturated oligomer decreases. However, extended periods at the polymerization temperature have been found to have little effect on both the conversion of monomer and the molecular weight of the products formed. The elevated temperatures of the polymerization require that the polymerization reactor be equipped to operate at elevated pressure sufficient to maintain the contents of the reactor as a fluid at the reaction temperature. In general, it is preferred to conduct the polymerization at from 1,000 to 5,000 pounds per square inch (psi), and more preferably at from 3,200 to 4,200 psi. In the process of the present invention, the one or more monomers, the at least one initiator and, optionally, the one or more solvents are combined to form a reaction mixture. The order of combining the components of the reaction mixture is not critical to the process of the present invention. In one embodiment of the present invention, it may be desirable to use one or more solvents, heat the one or more solvents to an elevated temperature, and add the one or more monomers and the at least one initiator to the heated solvent to form the reaction mixture. It is preferred to add the at least one initiator last. The reaction mixture can be formed at a temperature below, at or above the oligomerzation temperature. In one embodiment of the invention, it may be desirable to add an additional amount of one or more solvents to the oligomer product while the oligomer product is at an elevated temperature to maintain desirable fluidity and viscosity properties of the oligomer product. The reaction mixture may optionally contain metal ions, such as copper, nickel or iron ions or combinations thereof. The process of the present invention generally results in a relative conversion of the monomers into oligomer product of from 10 to greater than 95 percent relative to the initial amount of the one or more monomers present in the reaction mixture. If residual monomer levels in the oligomer mixture are unacceptably high for a particular application, their levels can be reduced by any of several techniques known to those skilled in the art. Preferably, any residual monomers which may be present in the oligomer mixture are distilled or "stripped" and recycled for later use. The process of the present invention results in oligomers having low molecular weights and narrow polydispersities. Furthermore, selected embodiments of the process result in products which do not require the removal of organic solvents and are not contaminated with high levels of salt. The process of the present invention can be used to produce oligomers having number average molecular weights below 5,000, preferably below 3,000, and most preferably from 200 to 1,000. The process of the present invention is useful for producing oligomers of the structural formula shown above wherein the sum of m and n is less than or equal to 50, preferably less than 20, most preferably less than 10. In a preferred embodiment of the present invention, the oligomer product is predominantly a mixture of terminally unsaturated dimers, terminally unsaturated trimers and terminally unsaturated tetramers. Dimers are oligomeric products of formula (I) wherein the sum of n and m is 1; trimers are oligomeric products of formula (I) wherein the sum of n and m is 2; tetramers are oligomeric products of formula (I) wherein the sum of n and m is 3. The oligomer product preferably contains from 5 to 95 percent of terminally unsaturated dimer, more preferably from 15 to 80 percent of terminally unsaturated dimer based on the total weight of oligomer product in the oligomer mixture. The oligomer product preferably contains from 5 to 95 percent of terminally unsaturated trimer, more preferably from 15 to 80 percent of terminally unsaturated trimer based on the total weight of oligomer product in the oligomer mixture. The oligomer product preferably contains from 0 to 90 percent of terminally unsaturated tetramer, more preferably from 5 to 70 percent of terminally unsaturated tetramer based on the total weight of oligomer product in the oligomer mixture. The oligomers prepared by the process of the present invention may be used, for example, as additives for detergents, including, for example, powdered laundry detergents, liquid laundry detergents, automatic machine dishwashing detergents, hand dishwashing detergents and cleaners. The oligomers may also be used as water-treatment additives or scale inhibitors. The oligomers may also be used, for example, as dispersants for pigments, minerals, clays, cosmetics, and formulated products such as soaps or agricultural chemical formulations. The oligomers may also be used as a soil humectant to prevent soil from drying and eroding. When the terminally unsaturated oligomers of the present invention contain, for example, a carboxylic acid group, the oligomers can be reacted with polyfunctional alcohols having two or more alcohol functionalities to form polyesters. Suitable polyfunctional alcohols include, for example, diols, triols and other polyols. Examples of suitable polyfunctional alcohols include, for example, sugars, glycerol, polysaccharides, poly(vinyl alcohols), ethylene glycol, propylene glycol, poly(ethylene glycol) and poly(propylene glycol). Preferably, the polyfunctional alcohol is ethylene glycol, sorbitol, sucrose, glucose or a mono-, oligo- or polysaccharide. The reaction of terminally unsaturated oligomers containing carboxylic acid groups with polyfunctional alcohols can be conducted in any suitable manner and is preferably conducted in the presence of an acid catalyst. Similarly, when the terminally unsaturated oligomers of the present invention contain at least one carboxylic acid group, the at least one carboxylic acid group can undergo a condensation reaction with any suitable amine to form a compound which is an amide, polyamide or poly(ester amide). Also, any suitable amine can undergo a Michael-type addition to the terminally unsaturated moiety of the terminally unsaturated oligomer to form a compound which is a Michael adduct, which may also undergo a reaction to form a compound which is an amide, polyamide or poly(ester amide). Suitable amines, include for example, amino acids, alkylamines, diamines, triamines and alkanolamines. Particular examples of suitable amines include ammonia, methylamine, lysine, ethylenediamine, ethanolamine and Jeffamines sold by Exxon Corp. Polyesters, amides, polyamides, poly(ester amides) or Michael adduct containing, as reacted units, the terminally unsaturated oligomers, are useful, for example, as additives for detergents, including, for example, powdered laundry detergents, liquid laundry detergents, automatic machine dishwashing detergents, hand dishwashing detergents and cleaners, as water-treatment additives or scale inhibitors, as dispersants for pigments, minerals, clays, cosmetics, and formulated products such as soaps or agricultural chemical formulations. Because the oligomers are terminally unsaturated, they can also be used, for example, as monomers in a subsequent polymerization, such as in a bulk polymerization, solution polymerization, emulsion polymerization, or suspension polymerization. The terminally unsaturated oligomers can be subsequently polymerized with themselves to form a homopolymer, or with one or more other ethylenically unsaturated monomers to form copolymers. The polymers resulting from the subsequent polymerization of the terminally unsaturated oligomers of the present invention may be useful, for example, in the same applications as the oligomers, or as adhesives, coatings, surfactants, adsorbents, ion-exchange resins and other polymeric applications. The terminally unsaturated oligomers can also be grafted onto any suitable substrate. Compounds which are suitable substrates are those which contain hydrogen atoms which can be abstracted by a free-radical. Examples of suitable substrates include: polyhydric alcohols such as sugars, glycerol, polysaccharides, and poly(vinyl alcohol); poly(ethylene glycol); poly(propylene glycol); and certain esters such as polycaprolactone. Preferably, the graft substrate is poly(ethylene glycol) (PEG), sorbitol, sucrose, glucose, or other mono-, oligo- or polysaccharide. THE EQUIPMENT AND GENERAL PROCEDURE A 10 foot long section of titanium tubing having an inner diameter of 1/16th inch and a wall thickness of 0.050 inch was connected at one end to a high pressure pump (Hewlett Packard Model HP 1050 TI) and at another end to a back-pressure control device. Between the two ends, the section of tubing was coiled about a torus-shaped metal mandrel. The mandrel was situated above a primary coil of a transformer so that the coils of titanium tubing and the mandrel functioned as secondary coils of the transformer. The coils of titanium tubing were further equipped with one end of a temperature probe. The other end of the temperature probe was connected to a temperature controlling device. The temperature controlling device regulated the current supplied to the primary coil of the transformer which had the effect of regulating the heat of inductance imparted to the coiled steel tubing. A reaction mixture was prepared by mixing solvent, monomer, and initiator. Helium was bubbled through the mixture while stirring. Deionized water was pumped through the tubing via the high pressure pump at a rate of from 0.05 to 10 milliliters per minute ("ml/min"). The pressure was maintained at a level of from 3300 to 5000 pounds per square inch ("psi"). Current was supplied to the primary coil of the transformer to increase the temperature within the tubing to the desired polymerization temperature. After about 15 minutes, the water being pumped through the tubing was replaced by the reaction mixture which was continuously pumped through the tubing at the same rate, temperature and pressure. After allowing a suitable amount of time for the water to be cleared from the tubing, product was collected as the effluent from the back-pressure control device. When the reaction mixture was nearly gone, deionized water was pumped through the tubing at the same rate, pressure and temperature as the reaction mixture. The molecular weights referred to are measured by gel permeation chromatography using a polyacrylic acid standard unless specifically stated otherwise. Terminal unsaturation was detected and measured by both .sup.1 H NMR spectroscopy and .sup.13 C NMR spectroscopy. Conversion was measured as a function of product solids, and was also determined by residual monomer analysis using high pressure liquid chromotagraphy. |
| PATENT EXAMPLES | This data is not available for free |
| PATENT PHOTOCOPY | Available on request |
|
Want more information ? Interested in the hidden information ? Click here and do your request. |