TWI525142B - Ethylene vinyl alcohol composition with metal carboxylate - Google Patents

Description

Ethylene-vinyl alcohol composition containing metal carboxylate

The present invention relates to a composition comprising an ethylene-vinyl alcohol copolymer and a metal carboxylate, an article comprising the composition, and a process for preparing the composition.

Ethylene-vinyl alcohol copolymer (EVOH) is a polymeric material with many uses, which has good oxygen barrier properties, oil resistance, antistatic properties and mechanical strength, and is widely used in a variety of packaging and packaging materials, such as: film, Sheets, containers, etc. In many applications, EVOH is used in one of the multilayer structures. For example, EVOH may be formed into a multilayer structure by coexruding with a polyolefin resin matrix or the like, wherein the EVOH layer and the matrix resin layer are bonded to each other with an adhesive layer. Therefore, in those structures, EVOH needs to have high interlayer adhesion.

EVOH can be made from a precursor polymer such as ethylene vinyl acetate. The melt viscosity of EVOH generally increases with time, especially at high temperatures. An increase in viscosity causes the molten EVOH to gel or solidify. This feature causes the metal surface of the processing apparatus to produce an unmanageable discoloration-deteriorating polymer varnish-like layer, resulting in an increase in the torque required for the extruder screw and, when detached, also results in sporadic gel particles in the molded product. Therefore, it is necessary for us to prepare an EVOH which does not exhibit gel-like particles and which does not exhibit an increase in viscosity, and further has a characteristic of lowering viscosity (viscosity decrease) when heated at a high temperature.

No. 4,753,760 discloses a process for preparing hydrolyzed ethylene-vinyl acetate copolymer pellets by extruding a methanol or water-methanol solution comprising a lubricant selected from one of the following: a saturated fatty acid amide, an unsaturated fatty acid amide , bis(fatty acid amide), metal salts of fatty acids and polyolefins. In addition, the techniques disclosed in JP-A-64-69653, U.S. Patent No. 5,118,743, U.S. Patent No. 5,360, 670, U.S. Patent No. 5,360, 670, U.S. Patent No. 5, 126, 954, U.S. Patent No. 5,118,743, U.S. Pat.

US 6,432,552 discloses an EVOH pellet characterized by a viscosity and torque change rate, wherein the pellet has a higher fatty acid alkaline earth metal salt of 12 to 18 carbon atoms adhered to the surface of the EVOH pellet, each EVOH pellet having a content of 30 Up to 300ppm.

No. 5,032,632 discloses an EVOH composition comprising a monovalent or divalent metal salt of an aliphatic carboxylic acid and a hindered phenolic antioxidant. No. 6,232,382 discloses an EVOH composition comprising acetic acid and magnesium acetate or calcium acetate; optionally a boron compound and/or sodium acetate, the examples showing a decrease in viscosity reduction and a rate of gel formation. No. 4,613,644 (equivalent to JP 60-199040) discloses a resin composition composed of a thermoplastic resin, an EVOH copolymer and a low molecular weight salt or oxide, providing a molded article free of white spots, the low molecular weight salt or oxide comprising At least one element selected from Groups I to III. No. 7,064,158 discloses an EVOH composition comprising a higher aliphatic carboxylic acid transition metal salt or metal salt. Also disclosed in US 2005/0096419 is an EVOH composition comprising a carboxylic acid and an alkali metal or alkaline earth metal salt which is resistant to gel formation. None of the techniques disclosed in these references reduce the likelihood of gelation in EVOH resins.

In the known art, EVOH has the property of poor adhesion, especially a non-polar polymer. And various means for improving the adhesion include incorporating a metal salt of a higher fatty acid, a metal oxide, a metal hydroxide, a metal carbonate, a metal sulfate, and a metal citrate into at least one layer of the EVOH (for example, JP54-87783) (for laminated structures). In addition, see US Pat. No. 6,485,842 and US Pat. No. 6,485,842.

In addition to this, in addition to the poor adhesion of EVOH, the calcium carboxylate content required to avoid gel formation to achieve the desired target viscosity reduction results in a worse adhesion of EVOH. In addition, the alkali metal salt required to increase the adhesion also causes an excessive decrease in viscosity. Finally, we need to develop a method of removing the gel already present in the EVOH composition. This compromises the adhesion of the prior art EVOH resin to improve the adhesion of the EVOH and renders the EVOH gel free and does not form a gel.

The present invention provides a composition comprising or consisting essentially of an ethylene-vinyl alcohol copolymer or an ethylene-vinyl alcohol copolymer, the composition comprising: about the weight of the copolymer 20% to about 50% of a repeating unit derived from ethylene; at least one alkali metal salt, wherein the content is calculated based on the number of microequivalents (μeq/g) of the alkali metal ion per gram of the composition, and the composition has a total of about 6.5. Μeq/g to about 10 μeq/g of the alkali metal ion; at least one alkaline earth metal salt, wherein the content is calculated according to the number of microequivalents of the alkaline earth metal ion per gram of the composition, and the composition has a total of about 0.5 μeq/g to About 2.5 μeq/g of the alkaline earth metal ion; and at least one carboxylate moiety having 3 to 18 carbon atoms, wherein the content is calculated based on the number of microequivalents of the carboxylate per gram of the composition, the composition having about 0.5 μeq/g to about 7 μeq/g of a carboxylate moiety having 3 to 18 carbon atoms.

The invention further provides an article comprising the above composition comprising a single layer or a multilayer structure which may be in the form of a film, sheet, tube, bottle, container, conduit, fiber, dish or cup.

The present invention further provides a process for the preparation of the above ethylene-vinyl alcohol copolymer composition, comprising: contacting a first composition comprising an ethylene-vinyl alcohol copolymer with a combination comprising, the ethylene-vinyl alcohol copolymer comprising 20% to about 50% by weight of the copolymer of the repeating unit is derived from ethylene, the composition comprising at least one alkali metal salt; at least one alkaline earth metal salt; at least one carboxylate moiety having from 3 to 18 carbon atoms And an optional ethylene-alcohol copolymer having from about 20% to about 50% by weight of the copolymer of repeating units derived from ethylene; wherein at least one alkali metal salt and at least one alkaline earth metal salt are The ratio in the composition is from about 2 to about 20 equivalents, and the ratio of the at least one carboxylate moiety to the at least one alkaline earth metal salt is from about 1 to about 15 equivalents.

The invention further provides a composition useful as a concentrate comprising: an ethylene-vinyl alcohol copolymer comprising from about 20% to about 50% by weight of the copolymer of repeating units derived from ethylene; at least one alkali metal a salt; at least one alkaline earth metal salt; and at least one carboxylate moiety having from 3 to 18 carbon atoms; wherein the ratio of the at least one alkali metal salt to the at least one alkaline earth metal salt is from about 2 to about 20 equivalents, and at least one carboxylic acid The ratio of the acid salt moiety to the at least one alkaline earth metal salt is from about 1 to about 15 equivalents, and wherein the amount is calculated based on the number of microequivalents of the alkaline earth metal ion per gram of the composition, the composition having a total of about 0.5 μeq/g to About 250 μeq/g of the alkaline earth metal ion.

The present invention further provides a process for preparing a modified ethylene-vinyl alcohol copolymer composition, comprising: melt-mixing a first composition comprising an ethylene-vinyl alcohol copolymer with a combination of the following components, the ethylene-vinyl alcohol The copolymer comprises from about 20% to about 50% by weight of the copolymer of repeating units derived from ethylene, the combination comprising at least one alkaline earth metal carboxylate having from 3 to 18 carbon atoms; optionally at least one alkali metal a salt; and optionally an ethylene-vinyl alcohol copolymer comprising from about 20% to about 50% by weight of the copolymer of repeating units derived from ethylene; to provide a modified ethylene-vinyl alcohol copolymer composition Wherein the content is calculated based on the number of microequivalents of the carboxylate per gram of the composition, the composition having from about 0.5 μeq/g to about 10 μeq/g of the carboxylate moiety having from 3 to 18 carbon atoms; The modified ethylene-vinyl alcohol copolymer composition has less gel than the first composition.

The present invention discloses an alkali metal and alkaline earth metal carboxylate additive mixture that improves EVOH characteristics. For example, the use of an alkali metal salt such as a combination of sodium carboxylate and an alkaline earth metal carboxylate such as calcium carboxylate provides the desired viscosity reduction characteristics and provides better EVOH adhesion relative to the adhesion of previous EVOH resins.

The viscosity reduction amount is characterized by comparing the viscosity of the EVOH composition with the viscosity of the shorter time treatment after the specified time treatment at the specified temperature. For example, the viscosity measured after mixing at 250 ° C for about 60 minutes is compared with the viscosity measured after mixing at 250 ° C for about 30 minutes (viscosity ratio). A viscosity ratio greater than 1, indicating an increase in viscosity; a value less than 1, indicating a decrease in viscosity. When the ratio is greater than 1, it is determined that the sample has been cross-linked, and cross-linking may result in gel particles or white spots. In the case of film applications of EVOH, gel particles are not desired to be produced based on aesthetic considerations. The gel forms pores in the EVOH layer, thus further reducing the oxygen barrier value. When the ratio is less than 1.0, the sample undergoes chain scission of the EVOH molecule, which contributes to minimizing gel formation during the EVOH melt treatment for a long period of time, and possibly reducing the number of visible gel particles.

In the process, it is not desirable that the viscosity ratio is higher than 2, and in the longer acting time, the viscosity ratio is higher than 2, and the gel may gradually form in EVOH. This may occur in production extrusion operations that typically last for several weeks, where the gel is produced on the walls of the extruder and eventually falls off into the extruded product. At the same time, it is not desirable to have a low viscosity ratio, for example, less than 0.1, because if the extrusion rate changes, the melt viscosity of the EVOH changes. For example, a lower production rate allows the melt to remain longer, resulting in a lower viscosity of the EVOH delivered to the die, resulting in dimensional changes in the extruded article.

The temperature range for extruding EVOH flakes varies from about 200 °C to 300 °C. The EVOH molecular weight reduction rate which occurs based on the combination of an alkali metal salt, an alkaline earth metal salt and a carboxylate is proportional to the melting temperature. For example, a composition treated at 250 ° C has a higher viscosity reduction rate, but the viscosity decreases at 220 ° C but is negligibly small. This change and the change in EVOH residence time show that the range of viscosity reductions that are applicable is large.

Under this condition, the composition may have a viscosity or torque ratio in the range of 0.1 to 2; 0.3 to 1.1; or 0.8 to 1. The desired viscosity ratio (as confirmed above) may be from 0.3 to 1.2, from 0.5 to 1.0 or from 0.7 to 0.95, such as from 0.8 to 0.95 or from 0.85 to 0.95.

Without being bound by theory, the carboxylate can cause EVOH to be broken when heated above the melting point of EVOH. The rate and extent of chain scission increase as the amount of carboxylate increases. For example, factors that increase alkalinity can further accelerate chain scission. Similarly, an increase in acidity can slow chain scission and/or increase the rate of crosslinking, which slows down the reduction in melt viscosity. The proper viscosity characteristics and the amount of additive required to reduce gel formation depend on the overall acid-base characteristics of the EVOH. Viscosity characteristics, gel formation and adhesion are also affected by the total content and type of salt present in the EVOH composition.

The EVOH polymer typically has from about 15 mole% to about 60 mole%, or from about 20 mole% to about 50 mole%, such as 28 mole%, 32 mole%, 38 mole%, 44 mole% Or 48 mole%, or about 28 mole% to about 48 mole% ethylene content. The density of commercially available EVOH is generally in the range of from about 1.12 g/cm ³ to about 1.20 gm/cm ³ and the polymer has a melting temperature in the range of from about 142 ° C to 191 ° C. The weight average molecular weight _Mw of the EVOH component calculated from the degree of polymerization and the repeating unit molecular weight is in the range of from about 5,000 to about 300,000 Daltons, or about 60,000 Daltons.

The copolymer component of the EVOH copolymer may comprise a comonomer. In embodiments in which a comonomer is used, the comonomer can be, for example, an alpha olefin such as propylene, isobutylene, alpha-octene, alpha-dodecene and alpha-octadecene, an unsaturated carboxylic acid, a salt. A partially or fully alkylated ester, a nitrile, an amide, an acid anhydride, an unsaturated sulfonic acid, a salt of the above compound, and the like. If comonomer is present, it is present in an amount from 0.1% to 10% or from 0.5% to 5% by mole.

The EVOH copolymer can generally be made by known techniques or by commercial sale. The EVOH copolymer can be obtained by saponifying or hydrolyzing an ethylene-vinyl acetate copolymer. Therefore, EVOH is also called a hydrolyzed ethylene-vinyl acetate (HEVA) copolymer. The degree of hydrolysis is preferably in the range of from about 50 mole % to 100 mole %, and the others preferably range from about 85 mole % to 100 mole %, such as 95 mole %. Alternatively, the EVOH copolymer can be obtained by treating the ethylene-vinyl acetate copolymer with a base catalyst such as sodium methoxide or sodium hydroxide in methanol and neutralizing it. This method initiates a transesterification reaction. When the desired high degree of conversion of the ethylene-vinyl alcohol polymer is achieved, the catalyst can be neutralized by adding a slight excess of an acid such as acetic acid, and the EVOH is precipitated by mixing or contacting with water or a low alcohol-water solution. . The resulting porous particles are filtered from the slurry and, in a final washing step, are washed to remove alcohol and salt by-products (e.g., sodium acetate) by washing with water of some weak acid acid to pH 4 to 5, followed by drying. Variations of this synthetic route are well known to those skilled in the art. Thus, depending on the processing conditions, small amounts of various salts, such as sodium acetate, may be present in the EVOH composition.

Commercially available EVOH polymers are commercially available under the tradename EVAL from Eval America (Houston, TX), Nippon Synthetic Chemical Industry Co., Ltd. (Japan) or Kuraray Company (Japan). The EVOH trade name may also be SOARNOL available from Noltex L.L.C. Such EVOH resins may be marketed under the trade name EVAL or EVAL SP, available from Eval Company (America) or Kuraray Company (Japan), and the like. Trade names for such EVOH resins include EVAL F101, EVAL F171, EVAL E105, EVAL J102, and EVAL SP 521, EVAL SP 292, and EVAL SP 482. Other EVOH resin trade names include SOARNOL DT2903, SOARNOL DC3203, and SOARNOL ET3803.

The alkali metal salts comprise ions including lithium, sodium, potassium, rubidium and/or phosphonium salts. The alkali metal salt used in the composition includes an alkali metal halide such as NaCl, an alkali metal phosphate compound such as sodium phosphate, lithium phosphate, disodium phosphate and sodium phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, hydrogen phosphate. Disodium or dipotassium hydrogen phosphate, an alkali metal boron compound such as an alkali metal salt of boric acid, borax, sodium borohydride or the like. Examples of alkali metal salts also include sodium acetate and potassium acetate.

The examples further include sodium metasilicate, ethylenediaminetetraacetic acid (EDTA), disodium calcium of sulfated castor oil, coconut oil, sodium salt of fatty acid, sodium salt of fatty acid, disodium edetate, citric acid Monosodium, sodium dihydrogen phosphate, derivatives of monoglycerol and diglycerin, sodium riboflavin phosphate, sodium 2-ethylhexyl sulfate, sodium alginate, sodium benzoate, sodium hydrogencarbonate, sodium hydrogen sulfate, sodium hydrogen sulfite , sodium carbonate, sodium citrate, sodium diacetate, sodium distearyl phosphate, sodium formate, sodium gluconate, sodium hydroxide, sodium hypophosphite, sodium iodide, sodium lactate, sodium lauryl sulfate, sodium nitrite, oleic acid Sodium, sodium palmitate, sodium potassium tartrate, sodium propionate, sodium salicylate, sodium sesquicarbonate, sodium tartrate, sodium thiosulfate, potassium aluminum citrate, lithium niobate, lithium iodide, lithium neodecanoate, Lithium palmitate, lithium stearate, potassium hydrogen phosphate, potassium oil of castor oil, dipotassium citrate, dipotassium edetate, potassium edetate, tetrapotassium edetate, citric acid Potassium, sulfated potassium oleate, potassium hydrogen tartrate, potassium alginate, potassium benzoate, potassium bicarbonate, carbon Potassium, potassium chloride, potassium citrate, potassium hydroxide, sodium hypophosphite, potassium iodate, potassium iodide, potassium lactate, potassium persulfate, tripotassium phosphate, potassium propionate, potassium ricinoleate, potassium sulfate, potassium tartrate Sodium and tripotassium citrate.

The alkaline earth metal salt is a metal ion such as an alkaline earth metal ion, and includes magnesium, calcium, barium, and/or barium salts. The alkaline earth metal salt used in the composition may include a halide such as CaCl ₂ , an alkaline earth metal phosphate compound such as calcium phosphate, calcium dihydrogen phosphate, dicalcium phosphate, and tricalcium phosphate. Examples further include calcium bromide, calcium carbonate, calcium glycerate phosphate, calcium iodate, calcium oxide, calcium sulfate, magnesium carbonate, magnesium chloride, magnesium hydroxide, magnesium oxide, magnesium phosphate, dibasic magnesium phosphate, trimagnesium phosphate, and B. Calcium disodium diamine tetraacetate and calcium ethylenediaminetetraacetate.

Preferably, the alkaline earth metal salt is added to the composition as an alkaline earth metal carboxylate, especially a carboxylate having from 3 to 18 carbon atoms, including magnesium carboxylate or calcium carboxylate, more preferably calcium carboxylate. Examples include calcium 2-ethylhexanoate, calcium acetate, calcium alginate, calcium benzoate, calcium citrate, calcium octoate, calcium citrate, calcium gluconate, calcium isoammonate, calcium isostearate, calcium lactate. , calcium myristate, calcium naphthenate, calcium neodecanoate, calcium oleate, calcium palmitate, calcium pantothenate, calcium propionate, calcium stearate, calcium stearyl-2-calcium, calcium zinc stearate , calcium or magnesium salt of plant fatty acid, magnesium 2-ethylhexanoate, magnesium citrate, magnesium octoate, magnesium citrate, magnesium glycerate, magnesium isophthalate, magnesium lauryl sulfate, magnesium linoleate, naphthenic Magnesium salts of magnesium magnesium, magnesium neodecanoate, magnesium oleate, magnesium palmitate, magnesium ricinoleate, magnesium salicylate, magnesium stearate, rosin zinc calcium salt and soybean oil fatty acid.

Carboxylates used as EVOH additives are prepared from organic acids having from 3 to 18 carbon atoms. They are preferably monobasic acids (having one carboxylic acid moiety per molecule), but polybasic acids including dicarboxylic acids such as tartaric acid, fumaric acid, citric acid, aconitic acid and adipic acid may also be used.

Examples of aliphatic organic acids include C ₂ to C ₂₄ , or C ₃ to C ₁₈ (e.g., C _3-9 , C _4-18 or C _6-9 ) acids. The acid is optionally substituted on the longest carbon chain having one to three substituents independently selected from a C ₁ -C ₈ alkyl group or a hydroxyl group. Examples of such organic acids include, but are not limited to, propionic acid, caproic acid, caprylic acid, capric acid, lauric acid, stearic acid, isostearic acid, oleic acid, palmitic acid, linoleic acid, or two or more thereof. A variety of combinations. Preferred are saturated organic acids such as stearic acid and octanoic acid. Aromatic acids such as benzoic acid and naphthoic acid can also be used.

Organic acids are commercially available as a mixture of specified organic acids with different lower levels of organic acids in a variety of different configurations. When the composition comprises a specified organic acid or a salt thereof, other unspecified acids may be present at a level conventionally known in the commercial supply of the acid or salt.

Salts of any of these organic acids include alkali metal salts (i.e., alkali metal carboxylates) such that the metal ions include alkali metal ions, including lithium, sodium, potassium, rubidium, and/or phosphonium salts. Preferred alkali metal carboxylates include lithium carboxylates, sodium carboxylates or potassium carboxylates.

The alkaline earth metal carboxylate includes magnesium carboxylate or calcium carboxylate, more preferably calcium carboxylate. Examples include calcium octoate and calcium stearate.

The composition can be prepared by blending using any method known to those skilled in the art, such as surface coating of resin pellets for further melt mixing or dry blending/mixing, extrusion, coextrusion, to produce the combination. Things. The composition can be a pellet blend, a dry blend, a pellet coated with a surface of some or all of the additive components, or a melt extruded blend. The composition can be prepared via a combination of heat and mixing (melt mixing or melt blending). For example, using a melt agitator such as a single screw or twin screw extruder, a blender, a Buss kneader (Coperion SA, Switzerland), a double spiral Atlantic mixer, a Banbury mixer, a wheel mixer, The component materials are mixed until substantially dispersed or homogeneous to obtain a resin composition. Alternatively, a portion of the component materials are mixed into a melt mixer, followed by the remaining component materials, and further melt mixed until dispersed or uniform in principle. The additive may also be surface coated onto the resin and subsequently mixed into the resin during the melt processing used to convert the pellets into finished products.

For example, a combination of an alkali metal salt, an alkaline earth metal salt and a carboxylate can be added by melt mixing the component in a batch mixing apparatus such as a hake mixer, a continuous twin screw or a single screw extruder or the like. Into alkaline EVOH resin.

Alternatively, a concentrate of an alkali metal salt, an alkaline earth metal salt, and a carboxylate in an EVOH copolymer composition can be prepared and added to an additional EVOH copolymer to produce a final composition.

A concentrate can be prepared wherein the amount of alkali metal salt, alkaline earth metal salt and carboxylate can be from 2 to 100 times (e.g., 5 times, 10 times, 20 times or 50 times) the amount required in the final EVOH composition. . Preferred concentrates may comprise from 20 to 50 times the amount required in the final EVOH composition.

The rate and extent of EVOH cracking increases as the total number of equivalents of salts, especially carboxylates, increases. For example, an unmodified EVOH sample having a 32% ethylene content has a viscosity ratio of about 3 at 250 ° C under the above test conditions; the same EVOH with 12 μEq calcium carboxylate has a viscosity ratio of 0.65; and has 12 μEq calcium carboxylate and The same EVOH of the additional 4.4 μEq sodium acetate has a viscosity ratio close to zero. Another unmodified EVOH has a viscosity ratio of about 2; the same EVOH with 12 μEq sodium acetate has a viscosity ratio of 0.40.

If a concentrate having a high concentration of the additive is obtained at 250 ° C, the molecular weight of the EVOH is lowered, resulting in a large decrease in the viscosity. This cracking can result in a concentrate melt that cannot be subjected to strand dicing, and/or any EVOH resin into which the concentrate is added has poor toughness. To avoid an excessive decrease in the molecular weight of the EVOH, the concentrate can be prepared at a temperature lower than that used to treat the final composition having the additive of the above concentration. Concentrates prepared using temperatures of about 220 ° C or less can achieve the desired performance.

The alkaline earth metal carboxylate can be added to the methanol solvent containing EVOH during the polymerization and hydrolysis. The thick liquid can be extruded into water to harden the EVOH and remove the solvent. During this operation, the alkaline earth metal carboxylate will adsorb into the EVOH solids. The resulting modified EVOH can be chopped and washed with water.

Alternatively, a combination of an alkali metal salt, an alkaline earth metal salt, and a carboxylate can be sprayed onto the EVOH pellets during the final step of the polymerization process. In some cases, one or more components of the combination can be mixed into the EVOH and the remaining components sprayed onto the pellets. For example, the EVOH resin may comprise an alkali metal salt, and the alkaline earth metal salt and the carboxylate may be sprayed onto the pellets. The alkali metal salt may be added to the resin, or it may be present in the resin as a result of the process conditions after the saponification or transesterification of the ethylene-vinyl acetate precursor. In some cases, it may be advantageous to coat the pellets with an alkaline earth metal carboxylate such as calcium stearate. Any coating applied can be dried during the normal final drying step of the resin pellets.

Coating the EVOH pellets extruded from the extruder with an alkaline earth metal carboxylate provides pellets having an alkaline earth metal carboxylate on the outer surface of the pellet. Coating the EVOH pellets obtained from the polymerizer with an alkaline earth metal carboxylate and then re-extruding those pellets is a method for preparing pellets in which an alkaline earth metal carboxylate is combined with an alkali metal salt such as sodium acetate. Incorporate into the interior of the pellet. In any event, the pellets can be re-extruded and processed into a finished product wherein the modifier combination herein provides a combination of viscosity characteristics and adhesion desired for EVOH.

An EVOH resin having an unacceptably high level of gel can be blended with an alkali metal salt, an alkaline earth metal salt, and a carboxylate in the EVOH copolymer composition to provide a final modified EVOH composition having a coagulation The gum content is lower than would be expected if the reduction in gel content was only caused by diluting EVOH with a high level of gel with a concentrate having a low level of gel. A suitable gel content can be less than about 2000, less than 1000, or less than 250 gels per 1.5 square feet of 1.5 to 2.5 mil thick film. Greater than 800 mm on the gel, the gel may be suitable number less than 20, less than 15, less than 10, or less than every 50ft ² 5 macrogel.

If necessary, the EVOH composition can be blended with different types of EVOH, each type of EVOH having a different degree of polymerization, a different ethylene content, and/or a different degree of saponification. If necessary, a suitable amount of various plasticizers, antioxidants, stabilizers, surfactants, colorants, ultraviolet absorbers, slip agents, antistatic agents, desiccants, crosslinking agents, metal salts, fillers A reinforcing agent such as various fibers or the like is added to the resin composition.

A suitable amount of any other thermoplastic resin may be added to the resin composition if necessary. Other thermoplastic resins which may be added to the composition include, for example, various types of polyolefins (e.g., polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene). a copolymer, a copolymer of ethylene and an α-olefin having at least 4 carbon atoms, a polyolefin-maleic anhydride copolymer, an ethylene-vinyl ester copolymer, an ethylene-acrylate copolymer, and a polymer thereof And modified polyolefins obtained by graft modification of copolymers with unsaturated carboxylic acids or their derivatives, etc.), different types of nylon (for example, nylon-6, nylon-6,6, nylon-6/6) , 6 copolymers, etc.), as well as polyvinyl chloride, polyvinylidene chloride, polyester, polystyrene, polyacrylonitrile, polyurethane, polyacetal, modified polyvinyl alcohol resin and the like.

The composition may comprise an antioxidant such as a hindered phenolic antioxidant. The hindered phenolic antioxidant can be one or more of a class of antioxidants characterized by a phenolic group having a bulky hindered substituent located ortho to the OH functional group. Such antioxidants are known products and are sold under various trade names. Suitable antioxidants include hindered phenolic antioxidants selected from the group consisting of 4,4'-thiobis(6-tert-butyl m-cresol), 1,3,5-trimethyl-2,4,6- Tris(3,5-tert-butyl-4-hydroxybenzyl)benzene, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropanoate, 3,5-di-tert-butyl-4- Octadecyl hydroxyhydrocinnamate, N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamamide), N,N'-trimethylene di(3,5 -di-tert-butyl-4-hydroxyhydrocinnamamide), bis(monoethyl(3,5-di-tert-butyl-4-hydroxybenzyl)phosphonic acid), 1,2-di(3,5- Di-tert-butyl-4-hydroxyhydrocinnamoyl)anthracene, bis(3,5-di-tert-butyl-4-hydroxyphenylpropionic acid)-1,6-hexane diester, and two or more thereof combination.

The EVOH composition can be formed into various molds such as films, sheets, containers, conduits, fibers, and the like. The molds can be used repeatedly by crushing them and recasting them. Films, sheets and fibers made from the composition may be uniaxially or biaxially stretched. The composition can be processed into these articles by extrusion, expansion extrusion, blow molding, melt spinning, injection molding, and the like. The temperature at which the resin composition to be molded melts differs depending on the melting point of the EVOH in the composition, but preferably ranges from about 150 to about 270 °C.

Alternatively, the EVOH composition can be molded into a single layer mold of the composition itself, or a multilayer structure comprising at least one layer of the composition, wherein the layer of the composition can be any form of film, sheet, or the like. . The multilayer structure can include a layer of EVOH composition, a layer of thermoplastic resin different from the EVOH composition, and a layer of adhesive therebetween.

The layer configuration of the multilayer structure includes, for example, E/Adh/T, T/Adh/E/Adh/T, and the like, wherein E represents an EVOH composition, Adh represents a binder resin, and T represents a thermoplastic resin. However, these are not limiting. In a multilayer structure, each layer can be a single layer, or multiple layers (as the case may be).

Any method of preparing the above multilayer structure can be used. Examples thereof include: a method of melt-extruding a thermoplastic resin onto an EVOH composition mold (for example, a film, a sheet, etc.); a method of coextruding an EVOH composition together with any other thermoplastic resin or the like; and making the EVOH composition and a method of co-injecting any other thermoplastic resin together; passing the EVOH composition via a known adhesive between the EVOH composition cast film or sheet and any other substrate, such as an organotitanium compound, an isocyanate compound, a polyester compound, or the like A method of laminating a cast film or sheet with any other substrate. Among them, a method of coextruding the EVOH composition together with any other thermoplastic resin is preferred.

The thermoplastic resin which can be laminated or coextruded with the EVOH composition includes, for example, a homopolymer or copolymer of an olefin such as linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene. a vinyl acetate copolymer, an ethylene-alkyl acrylate copolymer, an ethylene-propylene copolymer, a polypropylene, a propylene-α-olefin copolymer (wherein the α-olefin has 4 to 20 carbon atoms), polybutene, Polypentene, etc.; polyester, such as polyethylene terephthalate, etc.; polyester elastomer; polyamide resin, such as nylon-6, nylon-6,6, etc.; and polystyrene, polyvinyl chloride, poly Partially dichloroethylene, acrylic resin, vinyl ester resin, polyurethane elastomer, polycarbonate, chlorinated polyethylene, chlorinated polypropylene, and the like. Among them, preferred are polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyamide, polystyrene and polyester.

The multilayer structure can optionally include a layer of adhesive or a "bond" layer to facilitate bonding of the EVOH composition to another thermoplastic resin. For example, the binder resin preferably comprises a carboxylic acid modified polyolefin. The carboxylic acid-modified polyolefin can be obtained by chemically bonding an ethylenically unsaturated carboxylic acid or an anhydride thereof to an olefin polymer by, for example, an addition reaction or a graft reaction. The olefin polymer includes, for example, a polyolefin such as polyethylene (made by low pressure, medium pressure or high pressure), linear low density polyethylene, polypropylene, polybutene, etc.; an olefin and a comonomer capable of copolymerizing with an olefin ( For example, a copolymer of a vinyl ester, an unsaturated carboxylic acid ester or the like, such as an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, etc.; among them, a linear low density polyethylene, an ethylene-vinyl acetate copolymer is preferred. (having a vinyl acetate content of 5% to 55% by weight), and an ethylene-ethyl acrylate copolymer (having an 8% to 5% ethyl acrylate content by weight); and having a more linear low density Polyethylene and ethylene-vinyl acetate copolymer. The ethylenically unsaturated carboxylic acid and its anhydride include, for example, an ethylenically unsaturated monocarboxylic acid and an ester thereof, an ethylenically unsaturated dicarboxylic acid, and a monoester or diester thereof, and an acid anhydride. Among them, preferred ethylenically unsaturated dicarboxylic acid anhydrides such as maleic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride, monomethyl maleate, monoethyl maleate, Malay Diethyl acid, monomethyl fumarate, and the like. Most preferred are maleic anhydride, monomethyl maleate and monoethyl maleate modified polyolefin. Such polymers are available under the tradename BYNEL from E. I. du Pont de Nemours and Company (DuPont).

The amount of the ethylenically unsaturated carboxylic acid or its anhydride to be added to or grafted to the olefin polymer (i.e., the degree of modification of the polymer) may be from 0.0001% to 15% by weight based on the weight of the olefin polymer. Between 0.001% and 10%. The addition reaction or graft reaction of an ethylenically unsaturated carboxylic acid or an anhydride thereof and an olefin polymer can be produced by radical polymerization in a solvent (for example, xylene or the like) in the presence of a catalyst (for example, a peroxide or the like). .

Alternatively, the binder layer comprises a composition comprising ethylene and an ethylenically unsaturated dicarboxylic acid anhydride such as maleic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride, A copolymer of monomethyl maleate, monoethyl maleate, diethyl maleate, monomethyl fumarate or the like which can be obtained by a high pressure radical polymerization process. It is a "direct" copolymer, that is, a copolymer obtained by simultaneously adding all monomers. High pressure processes suitable for the preparation of such copolymers are described, for example, in U.S. Patent 4,351,931. This method provides a random copolymer having monomeric copolymerized units that react with each other to form the polymer chain. Further, the unit is incorporated into the polymer backbone or chain. These direct copolymers differ from the graft copolymers described above in that monomers are grafted onto existing polymers to form polymer chains having pendant groups.

The melt flow rate (MFR) of the carboxylic acid-modified polyolefin is preferably between 0.2 and 30 g/10 min, more preferably between 0.5 and 10 g/10 min, as measured at 190 °C. The binder resin may be a single layer or a combination of two or more layers.

For the co-extrusion of the EVOH composition with the thermoplastic resin, for example, any of the multi-channel collecting T-die method, the clamp-type feeding block current collecting T-die method, or the expansion method is applicable.

One of the characteristics of interlayer adhesion in a multilayer structure is "semi-finished adhesiveness", which is the adhesion exhibited in the first hour after the product is extruded. The processor uses this adhesion to judge the continued success of the extrusion activity. For the sake of simplicity, "adhesiveness" is used instead of "semi-finished adhesiveness". The adhesion between the EVOH composition and the adhesive layer is suitably from about 600 grams per inch to about 1500 grams per inch, or from 800 to about 1200 grams per inch. The composition optionally has (more adhesion to thicker structures in terms of semi-finished adhesion and thickness) greater than 300 grams per inch, greater than 500 grams per inch, or greater than 800 grams per inch. Force range.

The coextruded multilayer structure can be processed into various molds (e.g., films, sheets, tubes, bottles, etc.) including, for example, the following: (1) multilayer co-stretched sheets or films, which can be uniaxially Or biaxially stretching a multilayer structure (such as a sheet, a film, etc.), or biaxially stretching them, and then thermally fixing them; (2) multilayer rolling sheets or films by rolling a multilayer structure (3) a multi-layered dish or cup-shaped container formed by vacuum forming, press forming, vacuum-pressure forming or isothermal of a multilayer structure (eg, sheet, film, etc.) Formed; (4) a multi-layered bottle or cup shaped container made by stretch blow molding a multilayer structure such as a catheter or the like.

The method for producing the multilayer structure is not limited to the above, and any other known manufacturing methods (e.g., blow molding, etc.) can also be used for the structure.

Example Materials used

ADH-1: Linear low density polyethylene modified with 0.11% by weight of maleic anhydride grafted and having an MI of 1.1 g/10 min.

EVOH-32-1: EVOH containing 32 mol% of ethylene.

EVOH-32-2: EVOH containing 32 mol% ethylene and a melt flow rate of 5.4 dg/m at 210 ° C, which is obtained by inductively coupled plasma atomic emission spectrometry (ICP) 6 ppm calcium and 16 ppm sodium. Self-polymerization residue.

EVOH-32-3: EVOH containing 32 mol% ethylene and containing 9 ppm calcium and 48 ppm sodium as a residue.

EVOH-38-1: EVOH containing 38 mol% ethylene.

EVOH-38-2: EVOH containing 38 mol% of ethylene and having a melt flow rate of 4.4 dg/m at 210 ° C, and the EVOH containing 8 ppm of calcium and 19 ppm of sodium as a residue.

EVOH-44-1: EVOH containing 44 mol% of ethylene.

EVOH-44-2: EVOH containing 44 mol% ethylene and having a melt flow rate of about 8 dg/m at 210 ° C, the EVOH containing 2 ppm calcium and 14 ppm sodium as a residue.

HDPE: High density polyethylene.

Irganox 1010: Antioxidant available from Ciba Specialty Chemicals, Inc.

Calcium Citrate - available from Pechiney Ltd.

Calcium stearate - available from Scandinavian Formulas.

Sodium stearate - available from City Chemical.

Sodium acetate.

The anhydrous borax (Na ₂ B ₄ O ₇ ) is melted.

Disodium phosphate (Na ₂ HPO ₄ ‧ H ₂ O).

Sodium dihydrogen phosphate (NaH ₂ PO ₄ ).

The materials are mixed in a Haake blender or extruder.

To evaluate the adhesion of the EVOH composition, a 3-layer laminated blown film structure was prepared by co-extruding the following blow molded film: HDPE layer/ADH-1 layer/EVOH layer. The adhesion between the EVOH layer and the ADH-1 layer was measured using a T-peel test within about one hour of production. The multilayer structure was cut into strips of 1 inch (25.4 mm) wide in the longitudinal direction of the film and separated at the least secure interlayer. The separate strips were then placed in an Instron fixture and the peel force separating the strips was measured at a test speed of 12 inches per minute (0.305 meters per minute). Record the average of ten bars.

The compositions used in the table below were rated as unmodified compositions prior to compounding with the additives. The EVOH samples were melt blended at a rate of about 30 pounds per hour in a 30 mm Werner & Pfleider extruder. The melting temperature at the die is between 220 ° C and 230 ° C. The melt was extruded through a single hole mold (4.7 mm diameter) (no filter group) into strips which were subjected to water cooling and granulation treatment. The pellets were dried overnight at 100 ° C under vacuum and nitrogen. The pellets were measured in a capillary rheometer at 250 °C. In a closed rheometer, they were retained for a total of about 90 minutes and the readings were periodically read at a shear rate of about 72 s ^-1 . The ratio is obtained by dividing the viscosity reading at approximately 60 minutes by the reading at 30 minutes. The residue resulting from the polymerization is a metal element in the form of a cation present in the unmodified EVOH. Those elements were measured using ICP, and the viscosity ratio and the adhesion to ADH-1 were summarized in Table 1 (V indicates that the ratio is the viscosity ratio, and T indicates the ratio is the torque ratio).

In the table below, the viscosity ratio is the ratio of the torque or viscosity measured after 60 minutes of retention at 250 ° C to the torque or viscosity measured after about 30 minutes of retention. Torque values were generated in a Haake Rheomix 600 batch operated equipment using a 辗 wheel agitator operating at 50 rpm. The device was filled with 55 grams of resin and the closure was closed. A nitrogen seal is used around the top to minimize air. A viscosity reading was generated using a capillary rheometer where approximately 20 grams were retained in the capillary and the plunger was installed. The resin was left for 60 minutes. The viscosity reading was periodically read at a rate of 72 s ^-1 .

All of the examples in Table 2 contained 2.27 kg EVOH-32-1 and 4.54 g Irganox 1010. All other components in grams per unit are the same as those summarized in Table 1. Unmodified EVOH-32-1 contained 50 ppm Na and 7 ppm Ca residue and exhibited a semi-finished peel adhesion of 600 g/inch. The viscosity ratios exhibited by samples 85-2 and 85-5 compared to the respective samples 85-1 and 85-4 indicate the offset effect of the more acidic salt (proton donor salt) on the desired viscosity reduction effect.

The viscosity ratios exhibited by samples 85-2 and 85-5 compared to the respective samples 85-1 and 85-4 indicate the counteracting effect of the higher acidity salt (the proton-providing salt) on the desired viscosity reduction effect.

The composition was blended in a 30 mm W&P extruder using a screw having all of the conveying elements and about 5% of the kneading block elements. The screw was operated at a rate of 200 rpm at a set value of 175 °C. The pellets were cooled with water.

Samples were prepared using 3.18 kg EVOH and 6.36 g Iraganox 1010 as summarized in Tables 3 to 5. Unless otherwise expressed in ppm (by weight), the amounts of the other components are listed in grams. The data in Table 3 indicates that the alkaline earth metal carboxylate is comparable to the alkali metal carboxylate for the similarly equivalent carboxylate added. The acid salt more effectively results in the desired viscosity reduction characteristics. That is, the melt blended calcium octoate additive itself is a more effective component than the sodium acetate additive or the sodium acetate residue. Samples 52-13, 52-14, and 52-15 further indicate the greater potential of calcium octoate than sodium acetate, and also indicate that a small amount of calcium carboxylate added to the sodium carboxylate can increase the desired viscosity reduction of sodium carboxylate. Effectiveness. The viscosity ratio was measured by (60 minutes / 28 minutes).

When EVOH contains greater than about 100 ppm total sodium (110 ppm for 32%, 130 ppm for 38%, and 150 ppm for 44%), the adhesion is improved to above 800 grams/inch.

Table 4 shows an example with excellent adhesion (greater than 800 grams per inch, but with little or no viscosity reduction).

The data in Table 5 indicates that the composition containing only calcium carboxylate (Examples 95-11, 95-13, 95-14) has a high viscosity reduction and weakened adhesion. 95-15 and 95-16 show a combination of good adhesion and viscosity reduction for compositions comprising Na and Ca ions. Examples 95-16 are compositions comprising only sodium acetate.

In another experiment, 55 grams of unmodified EVOH-32-3 was melt blended at 250 ° C using a roller blade in a Haake Rheomix 600 twin screw batch mixer. The rate was 50 rpm and the torque was monitored for 60 minutes. The torque is proportional to the melt viscosity. The ratio of the torque at 60 minutes divided by the torque at 30 minutes is 1.7, which indicates that the viscosity increases with time. In another experiment, a 30 mm two-blade twin-screw extruder made by Werner & Pfleiderer was used to make EVOH-32-3 with 0.126% by weight calcium octoate, 0.11% by weight calcium stearate and 0.2% by weight Irganox 1010 melt compounded. The screw is designed as a forward conveying element having 5% kneading blocks of all its length. The melt temperature was 215 ° C, without the filter set, with a 4.7 mm diameter die, and the melt was pelletized at a 30 lb/hr rate pull down bar. The pellets were dried overnight at 100 ° C under vacuum. The viscosity stability of the pellets was analyzed in a Haake Rheomix 600 (55 g capacity) using a roller blade operating at 50 rpm and 250 ° C for 60 minutes. The ratio of the torque at 60 minutes to the torque at 30 minutes is 0.4. This ratio indicates that the melt viscosity decreases with time. The dried pellets were then added to a Prism A PM-44 16 mm two-blade twin-screw extruder set to 220 ° C; no filter set. The strand was cooled using dry ice (solid carbon dioxide), and the resin strand was pelletized without introducing moisture. The strand was pelletized and the pellet was re-extruded. Pellet samples were taken 4, 8 and 12 times by extruder.

The pellets were extruded into a blown film using a 1.9 cm single (25:1 L:D) screw extruder sold by CW Brabender Instruments, Inc. (South Hackensack, NJ) to add 3.5 mils. Ear (±1.5 mil) thickness in a circular die of blown film. The gel in the film was evaluated from the photograph of the film when the light was directed to the tangential direction of the film. The gel appears as a white spot. The number of gel particles larger than about 0.1 mm in diameter in an area of 4 cm 2 was manually calculated. The results are summarized in Table 6. This indicates that the gel present in the original sample (EVOH-32-3 with and without additives) ("no re-extrusion") was significantly reduced.

An increase in the gel reduction rate can be achieved by blending the EVOH with the additive and subjecting the melt to moderate mixing.

For comparison, the commercial 32% EVOH supplied by Kuraray under the name F101 will also be re-extruded and then extruded into a blown film. The number of gels of the resin which was not re-extruded and re-extruded 4 times, 8 times, and 12 times was constant to about 3 gels per 4 cm ² .

In another experiment, EVOH-32-3 pellets were melt compounded with 0.126% calcium octoate, 0.11% calcium stearate, and 0.2% Irganox 1010 as described above, and in a capillary rheometer via the method used above. The melt stability was measured, except that it was measured at 230 ° C instead of 250 ° C. The ratio of the viscosity at 60 minutes divided by the viscosity at 30 minutes was 0.99. The rheometer test for the new sample was performed at 210 ° C and the viscosity ratio was 1.15. This result indicates that the carboxylate additive does not cleave the EVOH molecules at a rate comparable to the rate at 230 ° C or especially at 250 ° C at 210 °C. This result indicates that the concentrate of the additive component in the EVOH carrier can be produced at a low temperature without the problem that the carrier itself is degraded.

In another embodiment, 50 grams of EVOH-32-2 and 0.2% by weight calcium octoate, 0.4% by weight sodium acetate, and 0.2% by weight Irganox 1010 are at Haake at temperatures ranging from 180 °C to 190 °C. Blend in a batch blender for 5 minutes. Ten parts of the resulting composition and 90 parts of EVOH-32-2 were added to the above-mentioned single-screw extruder fed to a blown film die. The cylinder was set to 250 °C. The treatment was continued until the steady state was reached, and then the device was turned off for 3 hours. Start processing again. The film gel content remaining in the die was monitored at two residence times. The film remaining in the die after a single residence time is the resin retained at the end of the feed of the single screw extruder. The gel in the film was monitored. For a single residence time film, it is expected that the additive-free EVOH-32-2 will have a very high gel number and the "concentrate" EVOH-32-2 made from 10% Haake. The sample formed has a low gel number and a reduced viscosity.

In another experiment, EVOH with 32% ethylene content and 1 μEq/g residual sodium was melt blended with sodium acetate to produce pellets containing 240 ppm sodium (10.4 μEq/g sodium) as determined by ICP. Blending [E107558-137] was carried out on a Prism twin-screw extruder and at a melt temperature of about 200 °C. The resulting pellets were dried overnight at 100 °C. The pellets were tested by leaving the pellets in a capillary rheometer at 250 ° C for 60 minutes. The viscosity intermediate test at a rate of 72 s ^-1 gave a ratio of viscosity at 60 minutes divided by viscosity at 30 minutes of 1.1. The same EVOH resin to which no sodium acetate was added had a ratio of 1.8. This result indicates that the added sodium acetate imparts a viscosity reducing effect.

EVOH containing 32% ethylene comonomer was prepared in a manner that retained sodium acetate. The total content of sodium in the resin was 190 ppm (8.3 μEq/g) [E109032-98] as determined by ICP. This resin sample was kept in a capillary rheometer at 250 ° C for 60 minutes. The ratio of the viscosity at 60 minutes divided by the viscosity at 30 minutes was 1.38. Another EVOH sample containing 89 ppm sodium (3.9 μEq/g) was obtained having a ratio of 1.53. This result indicates that residual sodium acetate can be used to produce a viscosity reduction effect.

In one experiment, to indicate that the carboxylate source could be aliphatic or aromatic, EVOH containing 32% ethylene and having 13 ppm residual sodium and 3 ppm residual calcium was melt blended with various additives in a Haake blender at 250 °C. 60 minutes. The torque is monitored. The results below indicate that aromatic or aliphatic carboxylates can reduce viscosity.

Run at a rate of 30 feet per minute using a 1.5 inch single screw extruder set at 210 °C with VOH-32-2, EVOH-38-2 and EVOH-44-2 by 20/60/20 ( The screw set was extruded and extruded into a 2 ± 0.5 mil thick film. The film was monitored by an automatic gel count (face check) apparatus "Film Test FSA100" using an OCS FS-5 camera, all supplied by Optical Control Systems GmbH (Witten, Germany). The gel present was recorded in units of gel particles per 50 square feet of film. A 1750 mm long 40 mm two-blade twin-screw extruder made by Werner & Pfleiderer was used to blend the same EVOH resin with sodium acetate (contents as shown in Table 6), 200 ppm calcium octoate, and 2000 ppm Irganox 1010. The screw is entirely composed of a forward conveying element having a kneading block of about 90 mm length. Do not use filter groups. The set value of the cylinder was about 190 ° C, and the resin melt was retained at about 205 to 210 ° C. The resin was extruded through a strand die, granulated, and dried to a moisture content of about 0.3%. This resin was processed into a film in the same manner as above, and gel count measurement was automatically performed. The results show that the chemically modified EVOH resin has a surprisingly reduced number of gels compared to the number of gels previously present in the resin. The results are summarized in Table 8.

The melt viscosity ratio and adhesion were determined ("good" means that the layers could not be separated) (adhesive force can be greater than about 900 g/inch) and are summarized in Table 9.

An unmodified similar film can be prepared from EVOH-32 and EVOH-38, or a modified similar film can be prepared by adding a combination of calcium octylate and sodium acetate. The pellets were obtained using the above conditions using a 30 mm extruder. The unmodified EVOH-32-3 and EVOH-38-2 pellets were processed by an extruder without addition of additives and stored. A new set of EVOH-32-3, EVOH-38-2 pellets, 200 pm calcium octoate, 580 ppm sodium acetate, and 2000 ppm Irganox 1010 additive were processed by an extruder. The four pellet samples were dried, then processed into a film and laser counted by the method described above. The results (Table 10) indicate that the presence of the additive combination is responsible for the reduced number of gels originally present in the unmodified EVOH pellets.

In another experiment, an additive concentrate was prepared by blending 55 grams of EVOH-32-2 with 2000 ppm calcium octoate, 20000 ppm Irganox 1010, and 5800 ppm sodium acetate at 225 ° C for 5 minutes at 125 rpm. When the temperature was kept constant at 225 ° C, the torque did not decrease. The resulting product was ground into granules having a size of about 2 mm. The granules were dry blended with EVOH-32-2 in a ratio of 1 part granule to 10 parts EVOH-32-2. The dry blend was added to a single screw extruder as described above, except that the screw was a mixing screw wherein about 33% of the screw had a limit to forcibly mix the melt. The extrudate was formed into a blown film having a thickness of about 2 mils. The unmodified EVOH-32-2 had a gel content of 10 gels per 4 cm 2 . The gel content of the modified EVOH-32-2 was 3 gels per 4 cm 2 .

Claims (18)

a composition comprising or consisting of a mixture of an ethylene-vinyl alcohol copolymer and a mixture comprising from 20% to 50% by weight of the copolymer of the ethylene-vinyl alcohol copolymer derived from ethylene; The mixture comprises at least one alkali metal salt, at least one alkaline earth metal salt, and at least one carboxylate moiety having from 3 to 18 carbon atoms, wherein the alkali metal salt is sodium acetate; the alkaline earth metal carboxylate is calcium octoate; The content of the carboxylate microequivalents per gram of the composition is calculated to have a total of 0.5 μeq/g to 7 μeq/g of the carboxylate moiety in the composition; and the composition is compared to the ethylene-vinyl alcohol polymer The gel formed is less; and the composition has a viscosity ratio of 0.3 to 1.2 and the film having a thickness of 1.5 to 2.5 mils made from the composition has a gel content of less than 2000 per 50 square feet. The composition according to claim 1, wherein the content is calculated based on the number of microequivalents (μeq/g) of the alkali metal ion per gram of the alkali metal salt of the composition, and the composition has a total of 6.5 μeq/g to 10 μeq/g of the alkali metal ion; and the content is calculated based on the number of microequivalents of the alkaline earth metal ion per gram of the alkaline earth metal salt of the composition, and the composition has a total of 0.5 μeq/g to 4 μeq/g of the alkaline earth metal ion. The composition of claim 2, wherein the composition further comprises an antioxidant comprising a hindered phenolic antioxidant Agent. The composition of claim 1, wherein the ratio of the alkali metal salt to the alkaline earth metal salt is from 1 to 20 equivalents; the ratio of the carboxylate portion to the alkaline earth metal salt is from 0.1 to 15 equivalents; The content of the alkaline earth metal ion microequivalent of the composition is calculated in the composition, and the composition has an alkaline earth metal ion of 0.5 μeq/g to 400 μeq/g. The composition of claim 1, wherein the composition has a content of microequivalents (μeq/g) of the alkali metal ion per gram of the alkali metal salt of the composition, and the composition has a total of 1 μeq/g to 2.5 The alkali metal ion of μeq/g; calculated according to the microequivalent number of the alkaline earth metal ion contained in the alkaline earth metal salt of the composition per gram, and the composition has a total of 0.5 μeq/g to 4 μeq/g of the alkaline earth metal ion in the composition. And the composition has from 0.5 μeq/g to 4 μeq/g of the carboxylate moiety. The composition according to claim 5, wherein the composition has a total of 2.5 μeq/g to 4 μeq/g of the alkaline earth metal ion of the alkaline earth metal salt; and the composition has a total of 2.5 μeq/g to 4 μeq/g. The carboxylate moiety. The composition according to claim 1, wherein the content is calculated based on the number of microequivalents (μeq/g) of the alkali metal ion per gram of the alkali metal salt of the composition, and the composition has a total of 2.5 μeq/g to 6.5 μeq/g of the alkali metal ion; Calculating the content of the alkaline earth metal ion microequivalents per gram of the alkaline earth metal salt of the composition, the composition having a total of 0.5 μeq/g to 4 μeq/g of the alkaline earth metal ion; and according to the composition per gram of the composition The carboxylate microequivalent number is calculated to have a total of 0.5 μeq/g to 4 μeq/g of a carboxylate moiety having 3 to 18 carbon atoms. The composition according to claim 7 wherein the composition has a total of 2.5 μeq/g to 4 μeq/g of the alkaline earth metal ion of the alkaline earth metal salt; and the composition has a total of 2.5 μeq/g to 4 μeq/g. The carboxylate moiety. An article of manufacture comprising the composition of claim 1 wherein the article is a single layer structure, a multilayer structure film, a sheet, a tube, a bottle, a container, a conduit, a fiber, a dish or a cup. The article of claim 9 wherein the article is a multilayer structure comprising a first layer, a binder layer and a second layer; the first layer comprising the composition; the second layer comprising a composition different from the composition a thermoplastic resin; the adhesive layer is interposed between the first layer and the second layer; and the adhesion between the first layer and the second layer is greater than 300 grams/inch. The article of claim 10, wherein the adhesive layer is in direct contact with the first layer and the second layer; and the thermoplastic resin is a polyolefin, a polyester, a polyester elastomer, a polyamide, a polystyrene , polyvinyl chloride, polyvinylidene chloride, acrylic resin, vinyl ester resin, polyurethane elastomer, polycarbonate, or a combination of two or more thereof; And the polyolefin is linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ethylene-alkyl acrylate copolymer, ethylene-propylene copolymer, poly A propylene, a propylene-α-olefin copolymer, a polybutene, a polypentene, a chlorinated polyethylene, a chlorinated polypropylene, or a combination of two or more thereof. The composition according to any one of claims 1 to 8, wherein the ethylene-vinyl alcohol copolymer comprises 30% to 44% of the repeating unit derived from ethylene; and the alkali metal salt is an alkali metal acetate a salt, and the carboxylate moiety is an alkaline earth metal carboxylate. The composition of claim 12, wherein the ethylene-vinyl alcohol comprises from 30% to 40% of the repeating units derived from ethylene. A process for producing a composition by contacting an ethylene-vinyl alcohol copolymer with a mixture under conditions effective to produce a composition, wherein the mixture comprises at least one alkali metal salt; at least one alkaline earth metal salt; at least one having from 3 to 18 carbon atoms a carboxylate moiety, wherein the alkali metal salt is sodium acetate; the alkaline earth metal carboxylate is calcium octoate; the composition is an ethylene-vinyl alcohol copolymer comprising 20% to 50% of the copolymer The weight of the repeating unit is derived from ethylene; the composition has less gel than the ethylene-vinyl alcohol copolymer, the composition has a viscosity ratio of 0.3 to 1.2 and is made from the composition having 1.5 to 2.5 The mil thickness film has a gel content of less than 2000 per 50 square feet; according to the carboxylate portion of the unmodified ethylene-vinyl alcohol copolymer per gram Calculating the content of the micro-equivalent number, the mixture having a total of 0.5 μeq/g to 10 μeq/g of the carboxylate moiety; the ratio of the alkali metal salt to the alkaline earth metal salt is from 1 to 20 equivalents; and the carboxylate portion is The ratio of the alkaline earth metal salt is from 0.1 to 15 equivalents. The method of claim 14, wherein the contact means melt mixing. According to the method of claim 15, the method further comprises contacting the composition with a second ethylene-vinyl alcohol copolymer; and the second ethylene-vinyl acetate and the ethylene-vinyl alcohol copolymer may be the same or different. The method of claim 16, wherein the mixture further comprises a second ethylene-vinyl alcohol copolymer, and the second ethylene-vinyl alcohol copolymer and the ethylene-vinyl alcohol copolymer may be the same or different. According to the method of claim 14, the method comprises melt mixing the first composition with the mixture, the first composition comprising a first ethylene-vinyl alcohol copolymer having from 20% to 50% The repeating unit of weight of the copolymer is derived from ethylene, the mixture comprising at least one alkaline earth metal carboxylate having from 3 to 18 carbon atoms; optionally at least one alkali metal salt; and optionally one of the second ethylene groups. a vinyl alcohol copolymer comprising 20% to 50% by weight of the copolymer of the repeating unit derived from ethylene; to produce a second composition comprising a second ethylene-vinyl alcohol a copolymer wherein the content is calculated based on the number of microequivalents of the carboxylate per gram of the composition, the composition having a total of from 0.5 μeq/g to 10 μeq/g of the carboxylate moiety; compared to the first composition, the first Two combination The object has less gel.