MXPA00006571A

MXPA00006571A - Method of modifying poly(ethylene oxide)

Info

Publication number: MXPA00006571A
Application number: MXPA/A/2000/006571A
Authority: MX
Inventors: H Wang James; M Schertz David
Original assignee: Kimberlyclark Worldwide Inc
Priority date: 1997-12-31
Filing date: 2000-06-30
Publication date: 2001-06-26

Abstract

A method of modifying poly(ethylene oxide) by grafting polar vinyl monomers, such as poly(ethylene glycol) methacrylates and 2-hydroxyethyl methacrylate, onto the poly(ethylene oxide) is disclosed. The grafting is accomplished by mixing the poly(ethylene oxide), the monomer(s) and an initiator and applying heat. Preferably, the method is a reactive-extrusion process. The resulting modified poly(ethylene oxide) has improved melt processability and may be used to thermally process articles which have improved properties over articles similarly processed from unmodified poly(ethylene oxide).

Description

* F METHOD TO MODIFY POLY (OXID DB ETILBNO) FIELD OF THE INVENTION The present invention is directed to a method for modifying poly (ethylene oxide). More particularly, the present invention is directed to methods for modifying poly (ethylene oxide) comprising vinyl monomers such as poly (ethylene glycol) methacrylates and 2-hydroxyethi methacrylate, in poly (ethylene oxide).

BACKGROUND OF THE INVENTION Disposable personal care products such as panty liners, diapers, tampons, etc. are of great convenience. Such products provide the benefit of sanitary use at one time and are convenient because they are quick and easy to use. However, the disposal of such products is a concern due to limited land space. The incineration of such products is undesirable due to concerns about increasing air quality and the difficult costs associated with separating such non-incinerable discarded items. Consequently, there is a need for disposable products.

Which can be quickly and conveniently discarded without throwing them in a landfill or without incineration.

It has been proposed to dispose of such products in private and municipal drainage systems. Ideally, such products will be disposable and degradable in conventional drainage systems. The products suitable for disposal in drainage systems and that can be discarded with water discharge in conventional toilets are called "disposable with water discharge". Disposal through waste disposal with water provides the additional benefit of providing a convenient and sanitary means of disposal. The personal care products must have a sufficient resistance under environmental conditions which are to be used and are capable of withstanding the high temperature and humidity conditions encountered during use and storage that still lose their integrity in contact with the water in the toilet. Therefore, a water-disintegrable matter having a mechanical integrity when dry is desirable.

Due to the unique interaction with water and body fluids, poly (ethylene oxide) (hereinafter referred to as PEO) is currently considered a component material for films, fibers and disposable products that can be disintegrated in water. Polyethylene oxide, - (CH2CH2O) n- is a commercially available water soluble polymer that can be produced from the polymerization ring opening of ethylene oxide Due to its water-soluble properties, polyethylene oxide is desirable for waste disposal applications. However, there is a dilemma in confused processing of polyethylene oxide, low molecular weight polyethylene oxide resins have desirable melt viscosity and melt properties for confused processing, but they have limited properties of this solid when processed with melt in structural articles such as movies.

An example of a low molecular weight polyethylene oxide resin is the POLYOX® WSR N 80 polyethylene oxide which is commercially available from Union Carbide. Polyethylene oxide POLYOX * WSR N-80 has an approximate molecular weight of 200,000 grams / mole as measured by redox measurements. As used herein, low molecular weight polyethylene oxide compositions are defined as polyethylene oxide compositions with an approximate molecular weight of less than about 200.0 grams / mole.

In the personal care products industry, spunbonded fibers and thinned disposable films with water discharge are desirable for commercial bioability and ease of disposal. Low melt strength and melt elasticity under polyethylene oxide of low molecular weight limit the capacity of the low molecular weight polyethylene oxide to be pulled into films having a thickness of less than about 1 mil. Even when low molecular polyethylene oxide can be thermally processed into film, calibrated-thin films of less than about one thousandth of an inch in thickness can not be obtained due to lack of melt strength and to the elasticity of the polyethylene oxide's melt. low molecular weight. Efforts have been made to improve the processing of polyethylene oxide by mixing said polyethylene oxide with a second polymer., a copolymer of ethylene and acrylic acid, and increased the strength of the melt. The blend of ethylene acrylic acid copolymer / polyethylene oxide is capable of being processed into films of about 1.2 mils of an inch. However, the mixture and the resulting film are not water soluble, especially at high levels of copolymers. Ethylene acrylic acid, for example, of about 30 percent by weight. More importantly, thin films made of low molecular weight polyethylene oxide are very weak brittle to be useful for personal care applications. The films of polyethylene oxide of molecular weight under a resistance to the low tension, a low ductility and s very brittle for commercial use. In addition, the films produced from the low molecular weight polyethylene oxides make brittle by storage to environmental conditions. Such films are broken if they are not suitable for commercial applications.

Higher molecular weight polyethylene oxide resins are expected to produce films with improved mechanical properties compared to the films produced from low molecular weight polyethylene oxide resins. An example of the polyethylene oxide of the low molecular weight is the POLYOX® polyoxyethylene of WSR 12K, which is commercially available from Union Carbide. The polyethylene oxide of POLYOX® WSR 12K has a reported approximate molecular weight of 1,000,000 grams / mole as determined by rheological measurements. As used herein, higher molecular weight polyethylene oxides are defined as polyethylene oxide with a higher approximate molecular weight including about 300,000 grams / mole.

The higher molecular weight polyethylene oxides have poor processability due to their high melt viscosities and poor melt pulls. The melt pressure and melt temperature are significantly elevated during melt extrusion of high molecular weight polyethylene oxides. During the extrusion of molecular weight polyethylene oxides, a severe melt fracture was observed. Only very thick sheets can be made from higher molecular weight polyethylene oxides. Higher molecular weight polyethylene oxides can not be thermally processed into films of less than about 3-4 mils in thickness. Higher molecular weight polyethylene oxides suffer from severe melt degradation during extrusion and melt processing. This results in the breakdown of polyethylene oxide molecules and in the formation of bubbles in the extrudate. The inherent deficiencies of the polyethylene oxides of higher molecular weight make it impossible to use the higher molecular weight polyethylene oxide d in aqueous films. Even when the addition of the high levels of the classifier to the higher molecular weight polyethylene oxides does not improve the melt processing sufficiently to allow the production of the thin films without the occurrence of melt fracture and film breakage. In addition, the use of plasticizers in the films causes latent problems due to the migration of the plasticizer to the surface of the surface film.

There is a dilemma in using polyethylene oxide d in fiber manufacturing processes. Low molecular weight polyethylene oxide resins, for example, 200,000 grams / mol have a desirable melt viscosity and melt reaction properties desirable for extrusion processing but the fibers can not be processed due to their low melt elasticities and its low melt strengths. Higher molecular weight polyethylene oxide resins, eg, greater than 1,000.00 grams / mole, have had melt viscosities that are very high for fiber spinning processes. These properties make conventional polyethylene oxides difficult to process fibers using conventional fibr fabrication processes.

The melt of extruded polyethylene oxide from the spinning plates and the fiber spinning lines consists of pulling and breaking easily. Polyethylene oxide resins form thin-diameter fibers using fiber-making processes that resist pulling and break easily. Polyethylene oxide resins do not form thin diameter fibers using conventional melt fiber manufacturing processes. Conventional polyethylene oxide resins can be processed confused in yarns with diameters in the range of several millimeters. Therefore, polyethylene oxide compositions with melt viscosities suitable for fiber processing and with higher melt elasticities and higher melt strengths are desired.

In the personal care industry, l disposable fibers linked with disposable water discharge are desirable for commercial bioability and ease of disposal. Polyethylene oxide fibers have been produced by solution setting processes. Nevertheless, it was not possible to melt polyethylene oxide fibers using conventional fib fabrication techniques, such as melt spinning. Melt processing techniques are more desirable than the set solution because the fundi processing techniques are more efficient and economical. Processing with molten fibers is necessary for commercial bioability. The polyethylene oxide compositions of the prior art can not be extruded into the melt with a suitable melt strength and elasticity to allow the attenuation of the fibers. Currently, the fibers can not be produced from conventional polyethylene oxide composition by spinning. molten.

Commercially available polyethylene oxide resins are therefore not practical for the processing of cast thin films, fibers or personal care applications. What is required in the art, therefore, is a means for overcoming its difficulties in the molten processing of polyethylene oxide resins currently available.

SYNTHESIS OF THE INVENTION The present invention is directed to the methods for improving the processing of polyethylene oxide. In particular, the present invention relates to methods for modifying polyethylene oxide to improve melt processing by grafting polar vin monomers such as poly (ethylene glycol) methacrylates or 2-hydroxyethyl methacrylate into polyethylene oxide. The graft is achieved by mixing the polyethylene oxide, the monomers and initiator and applying heat. In a preferred embodiment, the modification method is a reactive extrusion process, the modified polyethylene oxides according to the invention have improved melt processing and can be technically processed into films, fibers and other articles which have improved properties on the films , fibers and similarly processed articles of the unmodified polyethylene oxide compositions.

To overcome the advantages of the prior art, it is an invention teaches a method of grafting the functional polar products into the polyethylene oxide in the melt. Modification of polyethylene oxide reduces melt viscosity, melt pressure and melt temperature. Additionally, the modification of the higher molecular weight polyethylene oxide according to the invention eliminates the severe melt fracture observed with the extrusion of the polyethylene oxide of the unmodified higher molecular weight. The invention provides methods for producing thermally processable and improved polyethylene oxide resins by modifying the polyethylene oxide. Modified polyethylene oxide resins can be solidified into pellets for further thermal processing into useful forms such as films and thin fibers, which are in turn useful as components in personal care products.

As used herein, the term "graft copolymer" means a copolymer produced by combining two or more chains of constitutionally different characteristics, one of which serves as the column backbone and at least one of which is attached in some points along the column and constitutes a side chain. As used herein, the term "graft" means the formation of a polymer by joining the lateral chains or species at some points along the colum of the parent polymer. (See Sperling L.H. Introduction to Polymer Science 1986 pages 44-47 which is incorporated by reference in its entirety).

Modification of polyethylene oxide resins with starting molecular weights of between about 300,000 grams / mole allows polyethylene oxide resins to be pulled on films with thicknesses less than 0. mils. The modification of polyethylene oxide resins with starting molecular weights of between about 400,000 grams per mole to about 800,000 grams per mole and most preferred for the manufacture of films. The drawn films of the unmodified ethylene oxide compositions have a better smoothness and greater clarity than the pulled films of the modified low molecular weight polyethylene oxide n. The thermal processing of the higher molecular weight polyethylene oxide films modified according to the invention also results in films with improved properties on similarly processed films of modified low molecular weight polyethylene oxide films.

Modification of polyethylene oxide resins with starting molecular weights of between about 50, 00 grams / mol to about 400,000 grams / mol, allows the modified polyethylene oxide resins to be extruded into fibers using conventional melt spinning processes. Modification of polyethylene oxide resins with starting molecular weights of between about 50,000 grams per m to about 200,000 grams per mole is preferred for fiber manufacture. The modification of polyethylene oxide according to this invention, improves the melting properties of the polyethylene oxide allowing said polyethylene oxide to be modified by being melted and attenuated into fibers. Therefore, the modified polyethylene oxide can be processed into water soluble fibers using both meltblowing and spin bonding processes which are useful for liners, cloth type outer cover, etc., in products for the city Disposable personnel with water discharge. These features and advantages of the present invention will be apparent from a review of the following detailed description of the embodiments described.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 compares the melt rheology curve of an unmodified polyethylene oxide resin of approximate molecular weight of 600,000 grams / mol, Example 1, and the melt rheology curves of the modified polyethylene oxide compositions from the Polyethylene oxide resin of molecular weight of 600,000 g / mol, examples 2-5.

Figure 2 compares the melt rheology curve of an unmodified polyethylene oxide resin of approximate molecular weight of 1,000,000 grams / mole, example 6, the melt rheology curves of the modified polyethylene oxide compositions from the resin of polyethylene oxide of molecular weight of 1,000,000 g / mol, examples 7-10 Figure 3 shows the results of an infrared Fourier transformation analysis of films from an unmodified polyethylene oxide of an approximate molecular weight of 600,000 grams / mole, example 1; a polyethylene oxide d of an initial approximate molecular weight of 600.00 grams / mol modified with 4.9% by weight of HEMA and 0.28% by weight of initiator, example 3; and a polyethylene oxide of an initial molecular weight of 600,000 grams per mole modified with 4.9% by weight of PEG-MA and 0.32% by weight d initiator, example 5.

Figure 4 compares the molten rheology curve of a modified polyethylene oxide resin of approximate molecular weight of 600,000 g / mol, Example 1 and the melt rheology curves of the modified polyethylene acid compositions of the polyethylene oxide resin having an initial approximate molecular weight of 600,000 grams / mo with low initiator and monomer levels, examples 11-13.

Figure 5 compares the molten rheology curve of an unmodified polyethylene oxide of an approximate molecular weight of 300,000 grams / mol, example 14, and the melt rheology curves of the modified polyethylene oxide compositions of the polyethylene oxide resin q has an approximate initial molecular weight of 300,000 grams / mol examples 15 and 16.

Figure 6 compares the melt rheology curve of an unmodified polyethylene oxide of a molecular weight of about 400,000 grams per mole, example 17, and the melt rheology curves of the modified polyethylene oxide d polyethylene oxide compositions. which has an initial approximate molecular weight of 400,000 grams / mol, examples 18 and 19.

Figure 7 is a graph comparing the melt viscosities of a polyethylene oxide of molecular weight of 200,000 g / mol unmodified, Example A comparing against the melt viscosities of the same polyethylene oxide resin after modification , example 32.

Figure 8 is a 13C nuclear magnetic resonance spectrum of the modified polyethylene oxide of Example 32.

Figure 9 is a nuclear magnetic resonance spectrum 'H of the modified polyethylene oxide of Example 32.

DETAILED DESCRIPTION The improved fibers and films can be melt processed using the conventional methods of commercially available polyethylene oxide resins when modified in accordance with this invention. Polyethylene oxide resins useful for modification for the purposes of making a film, include, but are not limited to polyethylene oxide resins having approximate initial supported molecular weights ranging from about 300.0 grams / mole to about 8,000,000 grams / mol as determined by the rheological measurements. Such polyethylene oxide resins are commercially available from, for example, Union Carbide Corporation and sold under the trade designations POLYOX® WSR N-750 and POLYOX® UCARFLOC® Polymer 309 respectively. The modification of the polyethylene oxide resins with starting molecular weights of from about 300,000 g / mol to about 8,000,000 g / mol are desired and the modification of the polyethylene oxide resins with starting molecular weight from about 400,000 grams / mole around 8,000,000 are more desirable Commercially available resin within the desired ranges include, but are not limited to, POLYOX® WSR N-205 and POLYOX® WSR N 12K.

The fibers can be made using conventional methods of processing commercially available polyethylene oxide resins when modified in accordance with this invention. The polyethylene oxide resins useful for modification for fiber manufacturing purposes include, but are not limited to, polyethylene oxide resins having approximate initial reported molecular weights ranging from about 50,000 g / mol to about 400,000. grams per mole Higher molecular weights are desired to increase mechanical and physical properties and lower molecular weights are desired for ease of processing. Polyethylene oxide resins are desirable for making fibers, have molecular weights ranging from 50,000 to 300,000 grams / mol prior to modification and more desirable polyethylene oxide resins for the manufacture of fibers having molecular weights ranging from about 50,000 to 200,000 grams / mol before the modification. The modified polyethylene oxide compositions of the polyethylene acid resins within the aforementioned resins provide sociable balances between mechanical and physical properties and processing properties. The two polyethylene oxide resins within the ranges referred to above are commercially available from Union Carbide Corporation and are sold under the trade designations POLYOX® WSR N-10 and POLYOX® WSR N-80. These two resin have approximate molecular weights reported as determined by rheological measurements of about 100,000 g / mol and 200.00 g / mol respectively.

Other polyethylene acid resins available for example from Union Carbide Corporation with approximate molecular weight ranges are sold under the trade designations WSR N-750, WSR N-3000, WSR N-3333, WSR N-205, WSR N- 12K, WSR N 60K, WSR 301, WSR Coagulant, WSR-303. (See POLYOX®: Water Soluble Resins from Union Carbide Chemicals &Plstic Company Inc., 1991, which is incorporated herein by reference in its entirety). Both the polyethylene oxide powder and the polyethylene oxide pellets can be used in this invention, since the physical form of the polyethylene oxide n affects its molten mixed behavior for grafting reactions. This invention has been demonstrated by the use of powdered polyethylene d-oxide as supplied by Union Carbide. However, the polyethylene oxide resins to be modified can be obtained from other suppliers in other forms such as pellets. The polyethylene acid resins and modified compositions may optionally contain these additives such as plasticizers, processing aids, rheology modifiers, antioxidants, ultraviolet light stabilizers, pigments, dyes, slip additives, antiblocking agents, etc., which can be added before or after the modification.

A variety of polar vinyl monomers may be useful in the practice of this invention. The term "monomer" as used herein includes monomers, oligomers, polymer mixtures of monomers, oligomers and / or polymers and any other reactive chemical species which are capable of covalent bonding with a parent polymer, polyethylene oxide.L ethylenically unsaturated monomers contain a polar function group, such as hydroxyl, carboxyl, amino, carbonate, hal thiol, sulphonic, sulfonate, etc. are suitable for this invention and are desired.The desired ethylenically unsaturated monomers include acrylates and methacrylates Particularly desirable ethylenically unsaturated monomers containing a polar functional group are 2-hydroxyethyl methacrylate (hereinafter HEMA) and poly (ethylene glycol) methacrylates (hereinafter PEG-MA) .A particularly desirable poly (ethylene glycol) methacrylate poly (ethylene glycol ethyl ether) methacrylate) However, it is expected that a wide range of polar vinyl monomers will be cap Other similar effects as HEMA and PEG-MA to polyethylene oxide will be effective monomers for grafting. The amount of polar vinyl monomer in relation to the amount of polyethylene oxide may vary from about 0.1 to about 1 percent by weight of the monomer to the weight of the polyethylene oxide. Desirably, the amount of the monomer must exceed 0.1 percent in order to sufficiently improve the processing of the polyethylene oxide. More desirably, the amount of the monomer should be at the lower end of the range discussed above in order to decrease costs. A range of graft levels is demonstrated in the examples. Typically the monomer addition levels were between 2.5 percent and 15 percent of the weight of the base polyethylene oxide resin.

The invention has been demonstrated in the following examples by the use of PEG-MA and HEMA as the polar vinyl d monomers. Both PEG-MA and HEMA were supplied by Aldrich Chemical Company. The HEMA used in the examples was designated Aldrich, catalog No. 12,863-5 and the PEG-MA was designated Aldrich, catalog No. 40,954-5. The PEG-MA was poly (ethylene glycol) ethyl ether methacrylate having a wet average molecular weight of about 24 grams / mole. PEG-MA with a number-average molecular weight of less than 246 grams / mole is also applicable for this invention. The molecular weight of PEG-MA can vary up to 50.00 g / mol. However, lower molecular weights are preferred for faster graft reaction rates. The desired molecular weight range of the monomers is from about 246 to about 5,000 g / mol and the desired range is from about 246 to about 200 grams / mol. Again, it is expected that a wide range of polar vinyl monomer, as well as a broad range of molecular weights d monomer will be able to impart effects similar to polyethylene oxide resin and will be effective monomers for grafting and modification purposes.

A variety of primers may be useful in the practice of the invention. When the graft is achieved by the application of heat, as in an extrusion-reactive process, it is desirable that the initiator generates free radicals through the application of heat. Such initiators are generally mentioned as thermal initiators. For the initiate to function as a useful source of radicals for grafting, and initiator must be commercially available and easily, must be stable to environmental or refrigerated conditions, and must generate radicals at reactive extrusion temperatures.

The compounds containing an O-O, S-S N = N bond can be used as thermal initiators. Compounds containing O-O peroxides are commonly used as initiators for the polymerization and reactive extrusion processes. Such commonly used peroxide initiators include, but are not limited to, alkyl, dialkyl, diaryl and arylalkyl peroxides, such as cumyl peroxide, T butyl peroxide, di-t-butyl peroxide, dicumyl peroxide, cumyl butyl peroxide, 1, 1-di-t-butyl peroxy-3,5,5,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-b (butyl) peroxy) hexyne-3 and bis (at-butyl peroxyisopropylbenzene) acyl peroxides, such as acetyl peroxides and benzoyl peroxides; hydroperoxides such as cumyl hydroperoxide, butyl hydroperoxide, p-methane, pentane hydroperoxide eumeno hydroperoxide; peresters or peroxyesters such as butyl peroxypivalate, t-butyl perostoate, t-butyl perbenzoate 2,5-dimethylhexyl-2,5-di (perbenzoate) and t-butyl (pereftalate) alkyl sulfonyl peroxides; dialkyl dialkyl peroxybicarbonate peroxymonocarbonate; diperoxy ketals; ketone peroxides such as cyclohexanone peroxide and methyl ethyl ketone peroxide. Additionally, azo compounds, such as 2,2'-azobisisobutyronitrile abbreviated as AIBN, 2,2'-azobis (2,4-dimethylpentanenitrile) and 1,1'-azobis (cyclohexanecarbonitrile can be used as an initiator. demonstrated in the following examples by the use of a liquid organic peroxide initiator available from Elf Atochem Nort America, Inc., of Philadelphia, Pennsylvania, sold under the designation of the LUPERSOL® 101 brand (hereinafter L101) LUPERSOL® 101 is a free radical initiator and comprises 2,5 dimethyl-2,5-di (t-butylperoxy) hexane Other initiators and other classes of LUPERSOL® initiators can also be used as LUPERSOL® 130.

A variety of reaction vessels may be used in the practice of this invention. Modification of polyethylene oxide can be carried out in any container provided that the necessary mixing of polyethylene oxideof the monomer and the initiator are achieved and provide sufficient thermal energy for grafting purposes Desirably, such containers include any suitable mixing devices, such as Haake extruders, Brandend Plasticorders, single and multiple screw extruders, any other mechanical mixing device , which can be used to mix, combine, process or manufacture polymers. In a desired embodiment, the reaction device is a counter-rotating twin screw extruder ta as a Haake extruder, available from Haake of 53 West Centur Road, Paramus, New Jersey 07652 or a co-rotating twin screw extruder such as the extruder. twin screw combination ZSK-30 manufactured by Werner &; Pfleidere Corporation, of Ramsey, New Jersey. It should be noted that a variety of extruders can be used to modify the polyethylene oxide according to the invention whenever mixing occurs and heating.

The ZSK-30 extruder has multiple ports including ventilation ports and is capable of processing polymers at a rate of up to 50 pounds per hour. If a higher production rate is desired, an extruder or diameter can be used. ZSK-30 has two modular screws and contains a variety of screw elements. The extruder can include transport elements, blocks of kneading available left-hand screw elements, turbine mixing elements and other elements of various inclinations lengths. More particularly, the ZSK-30 extruder has a p of co-rotating screws arranged parallel to the center-to-center distance and the axes of the two screws to 26. millimeters. The nominal screw diameters are 30 m. The actual external diameters of the screws are 30 mm, the internal screw diameters are 21.3 mm. The wire depths are 4.7 mm. The lengths of the screws are 1328 mm and the length of the current processing section is 1338 mm.

The ZSK-30 extruder had 14 processing barriers, which are consecutively numbered 1 14 from the supply barrel of the array for the purpose of the description. The first barrel, the barrel? L, received polyethylene oxide and was not heated but cooled for water The other 13 barrels were heated. The monomer, HEMA, or e PEG-MA was injected into barrel # 5 and the initiator was injected into barrel # 6. Both the monomer and the initiator were injected through a pressurized nozzle injector also manufactured by Werner & Pfleiderer. In the order in which the polyethylene oxide is added, the monomer and the initiate is not critical and the initiator and the monomer can be added at the same time or in reverse order. However, the order used in the following examples is desired. The matrix used to extrude modified polyethylene oxide hydroxyls has 3 mm diameter openings which are separated by mm. The modified polyethylene oxide yarns were extruded in an air chilling band and then pelletized. The extruded polyethylene oxide melt strands were cooled by air on a conveyor belt cooled by a 20 foot long fan.

Another suitable extruder as the reaction device includes the Haake extruder. The modified polyethylene oxide compositions of Examples 31, 32 and 33 suitable for the purposes of fiber manufacture were modified by the reaction process using the Haake extruder. The Haake extruder that was used was a twin counter-rotating screw extruder that contained a pair of conical counter-rotating screws made to order. The Haak extruder had a length of 300 mm. Each conical screw had a diameter of 30 mm and the supply opening and a diameter of 2 mm in the matrix. The monomer and initiator were added to the feed throat of the Haake extruder contemporaneously with the polyethylene oxide resin.

The Haake extruder comprised six sections as follows: section 1 comprised a forward double-lumen pumping section having a high index angle or large screw inclination. Section 2 comprised a double-legged forward pumping section having a smaller screw tilt than section 1. Section 3 comprised a double-trailing forward pumping section having a smaller smaller screw tilt that that of section 2. Section 4 comprised a section of double-section moescado reverse pump where a complete section had notches. Section 5 a section of pumping for advance with notches and of double section containing two complete sections Y, section 6 comprised a section e pumping forward d double section having an inclination of intermediate screw that of section 1 and of the section 2 EXAMPLES Polyethylene oxide compositions Suitable for Film Manufacturing.

Examples 1-21 have been demonstrated by the use of ZSK-30 extruder as detailed above. For the following examples, the extruder barrel temperatures were set to 180 ° C for all seven zones of the extruder. The screw speed was set at 300 revolutions per minute. The polyethylene oxide resin was supplied to the extruder with a K-Tron gravimetric supplier at a rate of 20 pounds per hour. The selected monomer and initiator were fed by Eldex pumps into the extruder at various rates reported in Table 1. The extrusion conditions, the current barrel temperatures, the seven extruder zones, the melt temperature of the polymer, the extrusion of In this case, the percent strength was monitored by means of reactive extrusion for each of the 20 examples and reported in Table 2. Modified polyethylene oxide threads are air cooled on a 20-foot fan-cooled conveyor belt. length. The solidified yarn was then pelletized in a Conair pellet available from Conair of Bay City, Michigan.

The percentages by weight of the components used in the examples were calculated in relation to the weight of the base resin, polyethylene oxide, unless otherwise indicated. In the following examples, five polyethylene oxide resins of approximate molecular weight were used and tested: polyethylene oxide POLYOX® WSR 205 having a reported initial molecular weight of 300,000 g / mol was used in examples 1-5 and 11 -13 and 20; POLYOX WSR 12K polyethylene oxide having a molecular weight (initial approximate d 1,000,000 g / mol was used in examples 6-10) polyethylene oxide POLYOX® WSR N-750 having a reported initial approximate molecular weight of 300,000 g / mol was used in examples 14-16, POLYOX® WSR N-3000 polyethylene oxide having a reported initial approximate molecular weight of 400.00 g / mol was used in examples 17-19, and polyethylene oxide POLYOX® WSR N-80 had a reported starting molecular weight of 200,000 g / mol was used in Example 21.

Additionally, two monomers, HEMA and PEG-MA various levels of monomer addition ranging from as low as 0.80 percent by weight as high as 5.00 percent by weight of the monomer to the weight of the polyethylene oxide resin were used and they were tested in the examples. The relative amount of the initiator used in the examples ranged from 0. to 0.32 percent by weight of the initiator to the weight of the polyethylene oxide resin. The trade designation of the polyethylene oxide, the monomer and the amounts of polyethylene oxide, monomer and initiator used in the examples are listed in Table 1. Example 1 represents a control sample of unmodified polyethylene oxide of a molecular weight initial approximate of 600,000 grams / mol. The example represents a control sample of modified polyethylene oxide n of an initial approximate molecular weight of 1,000.00 grams / mole. Example 14 represents a control sample of unmodified polyethylene oxide of an initial approximate molecular weight of 300,000 grams / mol. Example 1 represents a control sample of a modified n-polyethylene oxide of an initial approximate molecular weight of 400.00 grams / mole. Example 20 represents a comparative example of polyethylene oxide of an initial approximate molecular weight 600,000 grams / mol modified only by the addition of the initiate without the monomer. And, Example 21 represents a comparative example of unmodified polyethylene oxide of an initial approximate molecular weight of 200,000 grams per mole.

Although the invention has been shown by way of example, it is understood that the polyethylene oxide, the polar vinyl monomer, the initiator and the conditions may vary depending on the type of modified polyethylene oxide composition and the desired properties.

TABLE 1 Components and Processing Conditions of the Examples The current processing conditions during the extrusion of the modified and modified polyethylene oxide examples listed in Table 1 were recorded under the current processing conditions during the extrusion of the modified and modified polyethylene oxide examples listed in Table 1. were registered < zse were reported in Table 2. Two extrusion runs were made for each of the reactive extrusion examples 2-and 7-10, and are reported as second values 2 '-5' and 7'-10 'respectively. Ti to T7 represent the actual barri temperatures of the seven zones of the extruder during the extrusion of the examples. Tj corresponds to barrels # 2 and # 3, T corresponds to barrels # 4 and # 5, T3 corresponds to barrels # 6 and? 7, T4 corresponds to barrels # 8 and # 9, T5 corresponds to barrels # 10 and # 11, T6 corresponds to barrels # 12 and # 13, and T7 corresponds to barrel # 14. Barrel # 1 was not heated remained under environmental conditions.

TABLE 2 Observed Extrusion Conditions 15 When the unmodified higher molecular weight polyethylene oxide resins, examples lyß were extruded under the above-mentioned processing conditions, the melt pressure during the extrusion of the unmodified polyethylene oxide resins was very high. The melt pressure of the 600,000 n modified molecular weight polyethylene oxide of Example 1 was 1770-1810 pounds per square inch and the melt pressure of the unmodified 1,000,000 molecular weight polyethylene oxide of Example 6 was d 1540- 1660 pounds per square inch. The high-shear heating of the extruder caused the melting temperatures of unmodified polyethylene oxide resins to increase significantly by 24 and 29 ° C, over the extruder bar temperature of 180 ° C. The melt temperature increased to 204 ° during the extrusion of the unmodified 600,000 molecular weight polyethylene oxide of Example 1 and increased to 209 ° C during the extrusion of the polyethylene oxide of the unmodified 1,000,000 molecular weight of Example 6. These factors contributed to the severe melt fracture and thermal degradation during the extrusion of unmodified higher molecular weight polyethylene oxide resins resulting in the production of unwanted yarns. The unwanted threads were characterized by threads wider than the broken threads tried, the threads connected to beads and the rough threads.

At the upper screw speed of 40 revolutions per minute, and at a lower production rate of approximately 5-10 pounds per hour, melt fracture was somewhat reduced. However, under these conditions, the degradation of polyethylene oxide appeared to be even more severe with significantly more bubbles developing within the yarns as they exited the matrix due to the increase in residence time in the extruder. The extruded polymer yarns had a foam-like appearance, which is undesirable. Additionally, the extruder set at 5 pounds per hour is an extremely low setting and is not practical for commercial applications.

For the grafting process of the modified higher molecular weight polyethylene oxide resins under the conditions, examples 2-5 and 7-10, the melt fracture was not visible producing yarns with smooth surfaces. Melt temperatures were significantly reduced as shown in Table 2. Melt temperatures by grafting HEMA and PEG-M to polyethylene oxide powders of POLYOX® WSR 205 of Examples 2-5 were in the range of 189 to 198 ° C, a reduction of 6 to 15 ° C compared to the melt temperature of the same non-grafted polyethylene oxide resin of Example 1 to 204 ° C. The threads also appeared to undergo less degradation, since the polymer threads contained fewer bubbles and were significantly smoother as they left the matrix. The melting temperature for the grafting of HEMA PEG-MA to the polyethylene oxide POLYOX® WSR 12K, Example 7-10, was also essentially reduced down to the range of 183 191 ° C compared to 209 ° C without a graft, example 6, a reduction of 18 to 26 ° C. This reduction in molten temperature d also apparently reduced the degradation within the extruder, since the polymer yarns contained fewer bubbles as they exited the matrix compared to the ungrafted polyethylene oxide resin itself.

Examples 14 and 17 showed some melt fracture and thermal degradation even if not as severe as was observed for examples 1-6. The most obvious problems with the extrusion of Examples 14 and 17 were the high melt pressure, 1379 and 1659 pounds per square inch and the increased torsional force, 33 and 33%. For the modified polyethylene oxide of examples 15, 16, 17 and 19, the melt pressure was reduced by more than 50% compared to the modified polyethylene oxide of the starting molecular weight itself and the torsional strength was slightly reduced for each one from 33 percent down to 26-28 percent. The melt temperature was not reduced for these examples.

Example 20, the polyethylene oxide POLYOX® WSR 205 modified by the addition of initiator only showed a remarkable change in the melt extrusion compared to example 1, the polyethylene oxide of modified POLYOX® WSR 105 n. The melt pressure was reduced from 1770-189 pounds per square inch to 313 pounds per square inch. L torque was reduced from 32-36% to 26%. And the melt temperature was reduced from 204 ° C to 198 ° C. These changes were expected to result primarily from the chemical degradation of polyethylene oxide in the presence of the free radical initiator, the same mechanism of chemical degradation as occurred for examples 2-5, 7-13, 15, 16, 18 and 19. However, because Example 20 was modified without the use of a monomer, the preferential reaction was crosslinking as opposed to grafting. The resulting material was filled with crosslinked gel particles some as large as 0.5 to 1 millimeter. The gels were made to the resulting unusable polyethylene oxide d.

Cross-linked gels were not observed or were significantly reduced in both size numbers, for the unmodified polyethylene oxides of examples 2-5, 7-13, 15-16 and 18-19. It is believed that the initiate preferably reacted with the monomer causing the graft to chain-split rather than cross-link. The modified polyethylene oxides of Examples 2-5, 7-13, 15-16 and 18-19 have properties beneficial for thermal processing in thin films and are useful for producing commercially useful articles such as disposable personal care products. .

In general, the modified polyethylene oxide of Examples 2-5, 7-13, 15-16 and 18-19 exhibited a reduced melt temperature and a melt pressure compared to the corresponding unmodified higher molecular weight polyethylene oxide. . This allowed an easier and more economical processing of polyethylene oxide. The appearance of the modified extrusion-modified polyethylene oxide according to this invention is greatly improved compared to the unmodified higher molecular weight polyethylene oxide. The extruded polyethylene oxide yarns modified in accordance with this invention are much smoother and more uniform in comparison to the extruded yarns of the same initial unmodified polyethylene oxide. The melting points were determined by DSC of the modified polyethylene oxides of Examples 2-5 and 11-13 are lower for the initial unmodified polyethylene oxide of Example 1. Similarly, the decreases in the melting points were observed for the modified polyethylene oxides of Examples 7-10 in comparison to the initial unmodified polyethylene oxide of Example 6, but the modified polyethylene oxides of Examples 15 and 16 as compared to the unmodified polyethylene oxide of the example 14 for the modified polyethylene oxide of Examples 18 and 19 as compared to the initial unmodified polyethylene oxide of Example 17. These measured decreases in the melting point for the unmodified polyethylene oxides are further evidence of the modification and are beneficial for thermal processing.

REHABILITATION OF FUNDIDO Melt rheology curves for the resin compositions of approximate initial molecular weight d 500,000 g / mol unmodified, example 1 and modified examples 2 5 are given in figure 1. The melt rheology curves for the resin compositions of Initial approximate molecular weight of 1,000,000 g / mol unmodified, example and modified, Examples 7-10 are given in Figure 2. The melt rheology curves for resin compositions of initial approximate molecular weight of 600,000 g / mol unmodified Example 1 and modified examples 11-13 are provided in Figure 4. Rheology curves for resin compositions of approximate molecular weight of 300,000 g / mol unmodified example 14 and modified examples 15 and 16 are provided in Figure 5. Melt rheology curves for resin compositions of approximate initial molecular weight d 400,000 g / mol unmodified, example 17 and modified examples 18 and 19 were provided onan in figure 6.

The results show that the melt viscosities of the modified polyethylene dies are significantly reduced at low cut-off rates of 50-100 s "1 than the melt viscosities of the modified n-polyethylene oxides, for example, the melt viscosity of the polyethylene oxide resin of approximate molecular weight of 1,000.00 unmodified 12K is 6.433 pascals per second at 50 s "1 and the viscosity of the same 12K resin modified with 5% of PEG-MA 0.32% of initiator LlOl was measured to 2,882 pascals per second the same cut rate, 50 s'1. This is a reduction in the melt viscosity of 55%.

However, at a higher cutting rate especially of 500-2000 s "1, the melt viscosities of the modified polyethylene oxides appear to be comparable to the melt viscosities of the modified n-polyethylene oxide.The melt viscosity of the resin The modified 12K was 275 pascals per second at 2,000 s1 and the melt viscosity of the same 12K resin modified with 5% of PEG-MA and 0.32% of the initiator is 316 Pa * s at the same cutoff rate of 2,000 sThis is an increase in the melt viscosity of 15%.

In general, the inclinations of the apparent viscosity against the cutting rate decreased after the modification.

NMR analysis The modified polyethylene oxide in the examples was analyzed by NMR spectroscopy. The results of this analysis confirmed that the modified polyethylene oxide d made contained grafted HEMA or PEG-MA units as side chain in the polyethylene oxide column. Mediated NMR spectroscopy, it was determined that the polyethylene oxide produced in examples 2-5, 7-13, 15-16 and 18-19 contained 0.6 to 2.58 percent of grafted HEMA or PEG-M side chains and from 0 to 2.39 percent of HEMA or PEG-MA n reacted or not grafted.

Process of Fraguado d «Pelíoula The unmodified extruded polyethylene oxide resins of Examples 1,6,14,17 and 21 were pelleted and attempts were made to process these resins of unmodified extruded polyethylene oxides into thin films. For film processing, a Haake twin screw extruder was used with either a 4-inch or 8-inch wide film die holder. The temperature profile for the heating zones of the Haake extruder was 170, 180, 180 and 190 ° C. The screw speed was adjusted in the range of 15-50 rpm depending on the film thickness tried, the screw speed and the winding speed were adjusted so that a film with a thickness within the range of 2 to 4 thousandths was produced of an inch The process was allowed to stabilize so that the samples of the film could be collected and observed. The extruded films were collected on a cooled coiling roll maintained at 15-20 ° C.

The Haake extruder that was used to Forming the films of the polyethylene oxide compositions was a twin counter-rotating screw extruder which contained a custom-made conical counter-rotating screw pair with the 4-inch wide film die attachment. The Haake extruder comprised six sections as follows: a composite section of a double-tram forward pumping section that has a large screw tilt and a high d helix angle. Section 2 comprising a double-legged forward pumping section having a lower screw pitch than section 1. Section 3 consisting of a double-trailing forward pumping section having a further screw inclination smaller than that of section 2. Section 4 composed of a section of reverse pumping with notches and double section where a complete section had notches. Section 5 consists of a section of pumping forward with notches and double section that contains two complete sections. And the section 6 composed of a double-section forward pumping section having an intermediate screw inclination between that of section 1 and section 2. The extruder has a length of 300 mm. Each conical screw has a diameter of 30mm in the supply port and a diameter of 20mm in the matrix. Even when the aforementioned extruder is described in detailIt should be noted that the variety of extruders and apparatus can be used to process polyethylene oxide films.

The modified extruded polyethylene oxide resins of Examples 1-6 were not capable of being processed into thin films. Only thin sheets of a thickness greater than about 7 thousandths of an inch are capable of being produced. Even these thick sheets exhibited several melt fractures. The stiffness and melt fracture of the leaves gave the leaves an undesirable type of closure appearance with sharp teeth at the edges. Unreported polyethylene oxide resins were not able to be normally processed into thin films under normal processing conditions.

The modified extruded polyethylene oxide resin of Example 14, which has the lowest weight of the high molecular weight polyethylene oxide resins tested was the most processable of the unmodified higher molecular weight polyethylene oxides. However, unmodified polyethylene oxide d, from example 14, polyethylene oxide POLYOX®WSR N-750 with a molecular weight starting at approximately 300,000 g / mol was still very difficult to process a uniform sheet of about 4 mils. inch thickness. All attempts to process a sheet less than thousandths of an inch thick resulted in a breakthrough emergence and very uneven films. The minimum bulk film that was capable of being processed from the unmodified 400,000 g / mol polyethylene oxide d of Example 17 was only about 5 mils.

The polyethylene oxide composition of the example can only be processed in a film about 3-thousandths of an inch thick. However, the 3-mil polyethylene oxide films of Example 2 contained numerous fish eye orifices. Even though the torsional force and pressure during processing of the films of Example 20 were low, the films contained so many gel inclusions that the gel inclusions propagated the defects in the films. At less than 3-thousandths of an inch, the fish eye holes became so large that they interconnected and caused breaks in the films.

The unmodified polyethylene oxide alone which was capable of being processed into a thin film was polyethylene oxide POLYOX®WSR N-80 of 200,000 g / mol of molecular weight under example 21. However, the processed films of the The modified low molecular weight polyethylene of Example 21 possess insufficient mechanical properties such as low tensile strength and low ductility and also exhibit an increased brittle form during storage under environmental conditions. Additionally, the processed film of the unmodified polyethylene oxide d of Example 21 contained undesirable grainy particles. These deficiencies render unmodified polyethylene oxide implants impractical for commercial use in personal care products.

In contrast, the films were successfully processed from modified and extruded polyethylene oxide compositions. The films were proceeded with melt from the extruded modified polyethylene oxide compositions. The films were processed with melt from the polyethylene oxide compositions of the examples tried for processed films of the unmodified polyethylene oxide compositions, examples 1,6,14,17,20 and 2 as detailed above. Films reports about thousandths of an inch thick were made. The velocity of the screw, the torsional force, the pressure and the temperature of the matrix for the processing of the films of the samples was measured and the averages of the measurements were reported in table 5.

TABLE 5 Movie Processing Conditions Attempts were made to process the films with acceptable solid state properties of higher molecular weight unmodified polyethylene oxide resins. These attempts were made using unmodified POLYOX®WSR 205 polyethylene oxide and unmodified POLYOX®WS 12K polyethylene oxide with approximate molecular weights of 600, 00 g / mol and 1,000,000 g / mol respectively. Polyethylene oxide POLYOX®WSR 12K could not be processed in a film. Therefore, torsional strength and pressure data were not collected for polyethylene oxide of POLYOX®WSR 12K, n modified, example 6 of table 5. Unmodified polyethylene oxide POLYOX®WSR 205 can not be extruded at lower screw speed. The torsional strength and pressure observed during the film processing of the modified P0LY0X®WSR 205 polyethylene oxide compositions of Examples 2-5 were dramatically reduced in comparison to polyethylene oxide POLYOX®WSR 205 non-matrix but lacks the desirable mechanical properties in a usable film.

The modified polyethylene oxide compositions of Examples 11-13 with lower levels of monomer addition processed in comparison to the modified polyethylene oxide compositions of Examples 2-5 also exhibited reduced torsional strength and pressure during processing. in comparison to the unmodified polyethylene oxide processed under similar conditions. The modified polyethylene oxide compositions of Examples 15 and 16 also exhibited a significantly reduced pressure and torsion force and a slightly reduced matrix temperature during processing as compared to unmodified polyethylene oxide of Example 14 when processed under similar conditions. . Generally the melt viscosity during the film processing of the modified polyethylene oxide compositions was reduced and the matrix pressure was reduced by more than 50%.

Very thin films were able to be processed from the modified polyethylene oxide compositions of examples 15 and 16, exhibited excellent processing. In contrast, polyethylene oxide of unmodified POLYOX®WSR N-750 having an initial approximate molecular weight of 300,000 g / mol was not capable of being processed into a film less than 4 mils thick and broke or emerged and It was uneven in thicknesses during attempts to process the films to 4 mils of an inch thick. Similarly, the modified polyethylene oxide compositions of Examples 18 and 19 also exhibited a significantly reduced pressure and torsion force and a slightly reduced matrix temperature during processing as compared to unmodified polyethylene oxide of Example 17 when processed under similar conditions and were able to be processed into very thin films that exhibited excellent processing. In contrast, the unmodified POLYOX®WSR N-3000 polyethylene oxide of Example 17 was not able to be processed into a film less than 5 mils thick and 5 mil films were produced as closes with teeth similar to those observed for example 1.

In general, the modified polyethylene oxide films did not stick to the chill roll. The modified polyethylene oxide films produced were smooth and soft and did not contain any grainy particles as did the unmodified low molecular weight polyethylene oxide extruded films of example 21. The films produced from the polyethylene oxide compositions generally had better smoothness, smoothness and greater clarity than similarly produced films of unmodified polyethylene oxide compositions. Therefore, it has been discovered that the films of the modified polyethylene oxide compositions exhibit significantly improved film processing and can be economically more easily processed into thin films useful for personal care applications in contrast to the films of the compositions of the invention. Modified polyethylene oxide n.

Tension properties of modified polyethylene oxide films.

Tension tests were conducted on the films produced from the compositions of Examples 12-13, 15, 16, 18-20 and Polyethylene Oxide Resin POLYOX®WSR N-80 as detailed above. The tensile properties of each of the films were tested and measured in the direction of the machine (md) in the transverse direction (cd) and were presented in table 6.

TABLE C Tension properties of the films The processed polyethylene oxide films of unmodified POLYOX®WSR N-80 of Example 21 possessed elongation values at low break. The mechanical properties of polyethylene oxide film of POLYOX®WSR N-80 were tested and measured within 24 hours of film processing and exposed to decrease considerably with aging.

Only thick films, not less than 7. sandths of an inch in thickness, are capable of being processed from the polyethylene oxide resin of modified POLYOX® WSR 12K n of Example 6. No properties in the transverse direction can be measured for the films of the Example due to the great variations in the thicknesses in the transversal direction of the films.

The mechanical properties of the processed films for the four polyethylene oxide compositions Examples 2-5, modified from the polyethylene oxide resins having a molecular weight of 600,000 grams per mole before the modification were tested. These films have high breaking elongation values ranging from 570 to 73 percent. These modified polyethylene oxide compositions have molecular weights and molecular weight distributions similar to the molecular weight and molecular weight distribution of the polyethylene oxide of POLYOX® WSR N-80 per have significantly improved mechanical properties compared to the processed films of the lower molecular weight polyethylene oxide d resin. It is believed that this improved mechanical properties is, at least in part, caused by the increased chain interactions between the modified polyethylene oxide chains introduced through the grafting of H? MA and PEG-MA threads in ethylene oxide. it is believed that the grafted polar groups result in the hydrogen bonding between the neighboring polyethylene oxide chains by linking the chains in both solid and molten state.

Even the modification of polyethylene oxide resins with low levels of monomers produces improved mechanical properties. This was demonstrated by the high elongation at break, the maximum stress and the energy measurements at break observed for the films of examples 1, 12 and 13. The grafting, even at low levels, improves the fundamental properties of polyethylene oxide allowing therefore the thin films are processed from polyethylene oxide In general, processed films of the modified polyethylene oxide compositions were found to have improved mechanical properties over similarly processed films of conventional resins. Modified polyethylene oxide films showed dramatic improvement in tensile properties, greater than 600 percent in tension and 200 percent in tension in the direction of the machine and greater than 1400 percent in tension and 200 percent in tension in the transverse direction. Additionally, the films produced from the modified polyethylene oxide compositions were observed to have properties balanced in the machine direction against the transverse direction.

These films exhibited improved upper pi tensions and energy values at break. Most importantly, these films had reduced modulus values which demonstrated their improved flexibilities compared to the modified polyethylene oxide films. The improved flexibility of the films containing the modified polyethylene oxide are particularly desirable for disposable applications with water discharge specifically for disposable person care products with water discharge.

Coalitative FT-IR analysis Fourier transform infrared spectroscopy analysis (FT-IR) was carried out on thin processed films of the compositions of Examples 1, 3 . The spectrum that was obtained from this analysis is shown in figure 3. The line is the spectrum observed for Example 1, polyethylene oxide of approximate molecular weight of 600,000 grams per mol not modified and extruded. the average line is the spectrum observed for Example 3, the polyethylene oxide d of approximate molecular weight of 600,000 g / mo grafted with 5 percent HEMA. And the upper line is the spectrum observed for Example 5, the polyethylene oxide has an approximate molecular weight of 600,000 g / mol grafted with 5 percent PEG-MA.

The small peaks observed at approximately 1,725 centimeters'1 in the upper and middle spectrum of Examples 5 and 3 respectively are the peaks of absorption pair PEG-MA and HEMA respectively. This absorption peak, approximately 1,725 centimeters "1, was not observed for the unmodified polyethylene oxide as shown in the lower spectr in Figure 3.

Crystal Morphology Polyethylene oxide film of unmodified POLYOX WSR 205 having a reported initial approximate molecular weight of 600,000 g / mol of Example 1 and a film produced from a modified sample of the same initial resin analyzed using polarized light microscopy. In addition to being of a greater thickness, the unmodified film possessed larger spherulite crystals than those of the film produced from the modified polyethylene oxide under the same processing conditions. The spherulites in the modified n sample were observed to be in the order of 20 50 microns in size, while the spherulites in the modified sample were not observable under the same amplification and are believed to be in the order of less than 1 miera. in size The crystalline structures of the films change dramatically due to grafting. It is believed that the improved mechanical properties of the films containing the modified polyethylene oxide are brought at least in part by the changes in crystal morphology. Additionally, the resistance of the films modified to the physical aging is expected to improve as a result of the improvement observed in the crystalline structure.

COMPARATIVE EXAMPLE A A polyethylene oxide resin having a molecular weight of about 200,000 g / mol was processed through a Haake extruder under similar conditions to the following modified examples of the invention for comparative purposes and to demonstrate that the oxide resins of conventional unmodified polyethylene can be processed with fiber melt. The unmodified polyethylene oxide resin of molecular weight of 200,000 grams per mole that was used for this comparative example was obtained from Planet Polymer Technologies. The resin obtained from Plane Polymer Technologies was in the form of a pellet and was compared with the POLYOX® WSR N-80 polyethylene oxide resin manufactured by Union Carbide Corporation.

For processing, the extruder barrel temperatures were set at 170, 180 and 180 degrees centigrade for the first, second and third heating zones, respectively, and 190 degrees centigrade for the matrix. The screw speed was set at 150 revolutions per minute. Polyethylene oxide resin was fed to the extruder at a production of about 5 pounds per hour. No monomer or initiator was added to the polyethylene oxide resin of Comparative Example A. The unmodified polyethylene oxide was extruded under the above-mentioned conditions, cooled in air and pelletized for later use. Attempts were made to melt process the unmodified polyethylene oxide of Comparative Example A into fibers. Because the molten polyethylene oxide of Comparative Example A had a low melt elasticity and a very low melt strength to allow the attenuation of the polyethylene oxide melt the fibers could not be melt processed using conventional fiber spinning technique such as the Lurgi gun, the start gun and the free fall. The extruded polyethylene oxide melt from the spin plate easily leapt back and did not allow the unmodified polyethylene oxide to be pulled into fibers. Only threads of about 1 to millimeters in diameter were able to be produced from the unmodified polyethylene oxide of Comparative Example A.

COMPARATIVE EXAMPLE B A polyethylene oxide resin having a molecular weight of about 100,000 grams per mole is processed through a Hakee extruder under the same conditions as those of Comparative Example A. Polyethylene oxide resin of molecular weight 100, 000 grams per mo that was used for this comparative example B was obtained from Planet Polymer Technologies and was in a pellet form was composed of the polyethylene oxide resin of POLYOX WSR N-10 manufactured by Union Carbide Corporation. Attempts were made to melt process the modified n-polyethylene oxide of Comparative Example B into fibers. D fibers of less than about 100 microns could not be processed with polyethylene oxide resin melt d 100,000 g per mole of unmodified molecular weight using conventional fiber spinning techniques. Even then the melt can only be pulled very slowly and the melt is easily broken, making the commercial production of the polyethylene oxide fibers impractical. Thus, Comparative Examples A and B demonstrate that prior art, unmodified polyethylene oxide resins can not be processed co-melted into fibers.

E J EMP L O S Compositions dß oxide dß Polyethylene Suitable for l Manufacture of Fibers Polyethylene oxide resin POLYOX® WSR N-1 of 100,000 g per mole was fed to a Haake extruder at 5. pounds per hour together with 0.53 pounds per hour of the PE MA monomer and 0.026 pounds per hour of the LUPERSOL® 101 lib radical initiator, Example 31 of Table 7. The POLYOX® WSR N-80 polyethylene oxide of 200,000 g per mole was modified in the same way with the same monomer and the initiator at the same relative amounts, Example 32 in Table 7. When monomer and initiator were added to the polyethylene oxide based resins during extrusion, the molten elasticities and the resistances of melted polyethylene oxide resins were visibly improved. These modified polyethylene oxide compositions were collected in volume and then ground in a powder form for further fiber processing.

The melt viscosities of the polyethylene oxide resins were found to have been substantially reduced by the modification with the monomer and the initiator. The melt viscosity of the polyethylene oxide resins of 200,000 grams per mole of modified and unmodified was measured. several cut rates and are presented in Figure 7. The melt viscosity of modified n-80 polyethylene oxide resin WSR N-80 was 319 pascalseconds (Pa * s hereinafter) at 1000 seconds "1. The melt viscosity of the same polyethylene oxide resin modified by the addition of a monomer and an initiator, Example 32 s reduced to 74 pascal seconds at the same cut rate.

The melt viscosities of Comparative Example A and Example 32 were determined by means of melt rheology tests carried out on a Geometrfert Rheograph 2003 capillary rheometry. The rheometer was operated with a matrix of a length / diameter of 30/1 mm to 19 mm. degrees Celsius. The apparent melt viscosities measured in second pascals were determined at apparent shear rates of 50, 100, 200, 500, 1000 and 2000 seconds "1 in order to develop rheology curves for each of the polyethylene oxide compositions. Rheology curves of the polyethylene oxide compositions are presented in Figure 7. Over the wide range of cut-off rates tested, modified polyethylene oxide exhibited apparent viscosities lower than those of polyethylene oxide from which it was modified.

The modification by grafting the monomer into the polyethylene oxide brought a 77 percent drop in the melt viscosity. The reduced viscosity brought about by the modification of the polyethylene oxide makes the spinning of polyethylene oxide fiber possible. The fibers of small mu diameters in the range of 20-30 microns were able to be continuously pulled from the modified polyethylene oxide resins above. The fibers within this diameter range are not useful for making non-woven fabrics bonded with yarn. Ethylene oxide fibers and fabrics are disposable as water discharges and dispersible in water and can be used as components in disposable personal care products with water discharge.

When the addition of monomer and initiator was stopped during the extrusion process, the properties of the polyethylene oxide resins reverted to their previous values and the fibers could not be pulled from the unmodified polyethylene oxide melt. This demonstrated that the modification occurs and improves the properties of polyethylene oxide which is critical for fiber manufacture and commercial viability.

Other examples of the modified polyethylene oxide resins were produced to further demonstrate the invention. These other examples of the modified polyethylene oxide resins were produced by varying: the molecular weights of 100,000 and 200,000 grams per mole, and the suppliers of polyethylene oxide, Union Carbide and Plane Polymer Technologies Inc., (a combiner here in advance abbreviated PPT); the monomers of 2-hydroxyethyl methacrylate and poly (ethylene glycol) ethyl ether methacrylate described above and the amount of monomers; the amount of the LUPERSOL initiator 101; and the extruder. The various parameters used in the various examples are listed in Table 7 given below. The percentages by weight of the components used in the examples were calculated in relation to the weight of the base resin, polyethylene oxide, unless otherwise indicated.

Table 7 Components and Processing Conditions of the Examples Examples 31, 32 and 33 were processed in a Haake extruder under similar conditions as described above in the Comparative Examples. The exact extrus design, temperatures and screw speed were used. However, Examples 31, 32 and 33 included the addition of monomer and initiator to the d-polyethylene oxide resin in order to modify the ethylene oxide resin. The listed amounts of the monomer and initiator were added to the Haake extruder feed throat contemporaneously with the polyethylene oxide resin. Examples 34, 35, 36 and 3 were modified in the extruder ZSK-30 detailed above. The fourteen heated barrels of the ZSK-30 extruder consist of seven heating zones. For the modification of Examples 34-37, the seven zones of the extruder ZSK-30 all set at 180 degrees centigrade and the screw speed s set at 300 revolutions per minute. The respective monomer HEM or PEG-MA as listed in Table 7 was injected into the barrel and the initiator was injected into the barrel 5. Both the monomer and initiator were injected through a pressurized nozzle injector at the rate listed. The order in which the polyethylene oxide, the monomer and the initiator are added to the polyethylene oxide is not critical. The initiator and the monomer can be added at the same time or in reverse order. It should be noted that the order used in the Examples is preferred.

Although the invention has been demonstrated by the examples, it is understood that the polyethylene oxide, the polar vinyl d monomer, the initiator and the conditions can be varied depending on the type of modified polyethylene oxide composition and the desired properties.

Process for Fiber Manufacturing Attempts were made to melt process the fibers of the polyethylene oxide compositions of Examples 31, 32, and 33 using conventional melt processing techniques. The modified polyethylene oxide compositions of Examples 31, 32 and 33 were melt-processable in fibers by a research-scale spin-bonding process, in contrast to the unmodified polyethylene oxide compositions of Comparative Examples A and B which could not be extruded in a melt with a suitable melt strength elasticity for fiber processing. The melt processing of the modified polyethylene oxide resins was demonstrated by a conventional spinning bonding process on an experimental spinning line comprising a single screw extruder, a melt metering pump and a spinning plac. Spinning processes were used to spin the fibers but were not used to bind the fibers.

The free fall fibers and hand pulled fibers and by an initiator gun on a fiber spinning line were produced from the modified polyethylene oxide composition of Example 31. The free fall fibers and the fibers pulled by a Lurgi gun and by means of an initiator pistol on a fiber spinning line the modified polyethylene oxide composition of Example 32 was produced. Free falling fibers and fibers pulled by an initiator gun onto a fiber spinning line were produced from The modified polyethylene oxide composition of Example 33.

Although no attempts were made to process the fibers of the modified polyethylene oxide compositions of Examples 34, 35, 36 and 37, the modified polyethylene oxide compositions are expected to be processable co-melted into fibers. The appearance of the modified and extruded polyethylene oxide compositions of Examples 34, 35, 3 and 37 was similar to the appearance of Examples 31, 32, and 33 exhibiting lower viscosities and a more sticky material. These reduced melt viscosities make fiber spinning of the modified polyethylene oxide compositions possible and are particularly advantageous for the manufacture of commercial fibr, especially when the methods required for melt processing are used.

Some of the modified polyethylene oxide compositions were converted into co-melt blown fibers. The fibers retained the same beneficial solubility as the unmodified polyethylene oxide. This property is particularly desirable for disposable applications with water discharge. The fibers produced by the spinning process were also soluble in water and therefore easily disposable with water discharge.

Physical Test and Characterization of Fibers Stress tests were carried out on fibers produced from the modified polyethylene oxide compositions of Examples 31, 32 and 33. Tests were carried out using a Syntech 1 tension tester / available from MTS Systems Corporation, Machesny Park Illinois. The diameter of the fiber was measured before the test after the fiber was tested with a one-inch grip separation and a crosshead speed of 500 mm / min. The diameters and tensile properties of the fibers produced from the modified polyethylene oxide resins of Examples 31, 32 and 33 were measured and reported in the Table given below. The fibers made of polyethylene oxide d 200,000 grams per mole were significantly more ductile than those of 100,000 grams per mole. For the fibers made from the same molecular weight polyethylene oxide base resin the additional levels of higher PEG-MA, for example 10% p weight, led to a significantly increased ductility of the fibers. The polyethylene oxide fibers pulled with Lurgi gun at 10% PEG-MA addition had a maximum stress of 7.2 MPa and 648 percent elongation breaking. These tensile property values are extremely favorable for fibers derived from polyethylene oxide considering that the modified polyethylene oxide is very brittle in nature.

Table 8 Stress Properties of the Fibers Produced from Examples 31-32 and 33 ßPC analysis The number average molecular weight (M "), the average weight molecular weight (^, and the average molecular weight) (Mj) of Comparative Examples A and B and Examples 31, 3 and 33 were determined by gel permeation chromatography. The GPC Analysis was carried out by American Polyme Standars Corporation of Mentor, Ohio. From these measurements, the polydispersity indices (Mw / Mn) of the respective examples were obtained. The various molecular weights and polydispersity of the examples are reported in the Table given below.

NMR analysis The modified polyethylene oxide composition of Examples 31, 32 and 33 was analyzed by NMR spectroscopy. The NMR spectrum 13C and lH of Example 32 is presented co in Figures 8 and 9, respectively. The results of the analysis conformed that the polyethylene oxide modifies contained PEG-MA units.

The grafting levels of the modified polyethylene oxide compositions of Examples 31, 32 and 33 measured by NMR analysis were reported as hundreds per pes of monomer per weight of polyethylene oxide base resin that was grafted to the resin of polyethylene oxide and s reported in Table 9. The percentages of the n-grafted monomer of Examples 31, 32 and 33 are in the similar form reported in Table 9.

Table 9 Chemical Properties of Comparative Examples A and B and the Modified Polyethylene Oxide Compositions of Examples 31 32 and 33 The molecular weights of the modified polyethylene oxide examples are significantly different from the corresponding unmodified polyethylene oxide resin. Significant reductions in molecular weight and polydispersity indices were observed after the reactive extrusion of the polyethylene oxide with the monomer and the initiator compared to the unmodified extruded polyethylene oxide of the comparative examples. The weight average molecular weight of polyethylene oxide N-80 fell 148 d, 100 grams per mole for the unmodified, but similarly processed, polyethylene oxide N-80 of Comparative Example A 97,200 grams per mole for the 5% grafted polyethylene oxide N-80 of Example 31 and 109,300 grams per mole for oxide N-80 10% grafted polyethylene from Example 3 Similarly, the weight average molecular weight of polyethylene oxide N-10 dropped from 115,900 grams per mole for the unmodified polyethylene oxide N-10 of Comparative Example B to 90.6 grams per mol for the N-10 10% polyethylene oxide graft of Example 33. Thus, the modification of the polyethylene oxide resins produced a significant reduction in weight average molecular weight. However, the number average molecular weight was not greatly affected by the modification, thus producing a significant decrease in the polydispersity index and thus a narrower molecular weight distribution.

The fundamental changes in the modified polyethylene oxide brought by the chemical graft would have profound and unexpected effects on the physical properties and melt processing of the polyethylene oxide as shown here and discussed above. The narrower molecular weight distributions of the modified polyethylene oxide compositions resulted in improved melt and solid state properties. Although it is not desired to be united by the following theory, it is believed that during the process of reactive extrusion of polyethylene oxide resins, and initiator began three competitive reactions: 1) the grafting of vinyl monomer in polyethylene oxide , 2) degradation of polyethylene oxide and 3) cross-linking of polyethylene oxide. A novel method to achieve improved properties has been developed and is contrary to the methodology and traditional thinking in polymer development. The method degrades the polymer into shorter chains and opposes only increasing the molecular weight by grafting and cross-linking. The resulting modified polyethylene oxide compositions have improved melt strength and melt elasticity, overcoming the inherent deficiencies of both the low molecular weight polyethylene oxide and the higher molecular weight polyethylene oxide.

In the case of grafting, the presence of a sufficient amount of monomer or monomers as demonstrated in the examples given herein, the crosslinking and insignificant and does not adversely affect the properties of the modified polyethylene oxide. The crosslinking reaction only predominates where there is very little or no monomer present during the modification of the polyethylene oxide resin. Therefore, the degradation and grafting reactions of the polyethylene oxide must predominate and are desired to produce oxide compositions. of polyethylene suitable for the purpose of manufacturing films and fibers.

The modified polyethylene oxide resins are observed because they have improved melt strengths melt elasticities, overcoming the inherent deficiencies of both the lower molecular weight polyethylene oxide and the higher molecular weight polyethylene oxide. These improved melt properties allow the modified polyethylene oxide to be processed into useful fibers with diameters d less than 100 microns using conventional fiber pulling techniques. These same improved melt properties also allow modified polyethylene oxide resins to be processed into useful films with thicknesses less than 0.5 mils and with improved and balanced solid state properties.

The present invention has been illustrated in detail by the specific examples given above. It is understood that these examples are illustrative modalities and that this invention is not limited by any of the examples or details in the description. Those skilled in the art will recognize that the present invention is capable of many modifications and variations without departing from the scope of the invention. Therefore, the detailed description and examples are intended to be illustrative and are not intended to limit in any way the scope of the invention as set forth in the following clauses. In addition, the appended claims herein should be broadly considered within the scope and spirit of the invention.

Claims

R g iv i y p i c i o y g g

1. A method to modify poly (ethylene oxide) comprising: adding a poly (ethylene oxide), an initiator, a polar vinyl monomer in a reaction vessel; Y mixing the poly (ethylene oxide), the initiator, the polar vinyl monomer under conditions sufficient to graft the polar vinyl monomer onto the poly (ethylene oxide).

2. The method as claimed in clause 1, characterized in that the initiator is a free radical initiator.

3. The method as claimed in clause 1, characterized in that the polar vinyl monomer selected from the group consisting of poly (ethylene glycol) methacrylates and 2-hydroxyethyl methacrylate.

4. The method as claimed in clause 3, characterized in that the polar vinyl monomer is a poly (ethylene glycol) methacrylate.

5. The method as claimed in clause 4, characterized in that the poly (ethylene glycol methacrylate) is poly (ethylene glycol), ethyl ether methacrylate and has a number average molecular weight of no more than about 5,000 grams per mole.

6. The method as claimed in clause 2, characterized in that the polar vinyl monomer is 2-hydroxyethyl methacrylate.

7. The method as claimed in clause 1, characterized in that the reaction vessel is an extruder.

8. The method as claimed in clause 1, characterized in that the conditions sufficient to graft the polar vinyl monomer into the poly (ethylene oxide) comprises heating the poly (ethylene oxide), the polar vinyl monomer and the initiator .

9. The method as claimed in clause 8, characterized in that conditions sufficient to graft the polar vinyl monomer into the poly (ethylene oxide) comprise heating the poly (ethylene oxide), the polar vinyl monomer and the initiator of free radical at a temperature within the range of the melting point of poly (ethylene oxide) at the decomposition temperature of poly (ethylene oxide).

10. The method as claimed in clause 9, characterized in that the appropriate conditions for grafting the polar vinyl monomer to the poly (ethylene oxide) comprise heating the poly (ethylene oxide), the polar vinyl monomer and the initiator of free radical at a temperature within the range of about 120 ° C to about 220 ° C.

11. The method as claimed in clause 1, characterized in that the poly (ethylene oxide) has an initial approximate molecular weight ranging from about 50,000 grams per mole to about 8,000,000 grams per mole.

12. The method as claimed in clause 11, characterized in that the poly (ethylene oxide) has an initial approximate molecular weight ranging from about 300,000 grams per mole to about 8,000,000 grams per mole.

13. The method as claimed in clause 1, characterized in that the poly (ethylene oxide) has an initial approximate molecular weight ranging from about 50,000 grams per mole to about 400,000 grams per mole.

14. The method as claimed in clause 13, characterized in that the poly (ethylene oxide) has an initial approximate molecular weight ranging from about 50,000 grams per mole to about 200,000 grams per mole.

15. The method as claimed in clause 1, characterized in that the polar vinyl monomer added within the range of about 0.1 to about percent by weight relative to the weight of the poly (ethylene oxide)

16. The method as claimed in clause 1, characterized in that the polar vinyl monomer added within the range of about 0.5 to about 1 weight percent relative to the weight of the poly (ethylene oxide).

17. The method as claimed in clause 1, characterized in that the initiator is aggregated within the range of about 0.05 to about 0.35 weight percent relative to the weight of the poly (ethylene oxide).

18. The method as claimed in clause 17, characterized in that the initiator is aggregated within the range of about 0.10 to about 0.35 weight percent relative to the weight of the poly (ethylene oxide).

19. The method as claimed in clause 18, characterized in that the initiator is added from the range of about 0.15 to about 0.25 weight percent relative to the weight of the poly (ethylene oxide).

20. A modified poly (ethylene oxide) produced by the method as claimed in clause 1.

21. A method for grafting a polar vinyl monomer onto a poly (ethylene oxide) comprising: adding to a reaction vessel poly (ethylene oxide) from 0.1 to about 20 weight percent relative to the weight of the poly (ethylene oxide) of a vinyl monomer selected from the group consisting of poly (ethylene glycol methacrylate) and 2-hydroxyethyl methacrylate and a free radical initiator; mix the poly (ethylene oxide), the polar vinyl monomer and the free radical initiator; Y heating the mixture to above the melting point of the poly (ethylene oxide) to form a polyethylene oxide grafted.

22. A method for reactive extrusion that comprises: adding a poly (ethylene oxide) of about 0.1 percent by weight of a polar vinyl monomer selected from the group of poly (ethylene glycol) methacrylate and 2-hydroxyethyl methacrylate in relation to the weight of poly (ethylene oxide) and a free radical initiator in an extruder; mixing and heating the poly (ethylene oxide), and polar vinyl monomer and the free radical initiator while being extruded in order to graft the polar vinyl monomer and the poly (ethylene oxide). B g g v n c y A method for modifying polyethylene oxide by grafting polar vinyl monomers, such as poly (ethylene glycol) methacrylates, and 2-hydroxyethyl methacrylate, and poly (ethylene oxide) is described. mixing the poly (ethylene oxide), monomers and initiator and applying heat Preferably, the method is a reactive extrusion process The resulting modified polyethylene oxide has improved melt processing and can be used to thermally process articles those which have improved properties over the similarly processed articles of unmodified poly (ethylene oxide).