JP2015516472A - Ionomer-poly (vinyl alcohol) blends and coatings - Google Patents

Abstract

Characterized by (i) (i) a degree of hydrolysis of 80-94 mol% and a 4 wt% aqueous viscosity at 20 ° C of 15 centipoise (cp) or less; or (ii) a degree of hydrolysis of 95 mol%-100 mol% A poly (vinyl alcohol) composition comprising: a poly (vinyl alcohol) composition; and ethylene and a parent acid copolymer comprising 18-30 wt% acrylic or methacrylic acid, the acid copolymer comprising 200-1000 g / 10 Blends with ionomers having a melt flow rate (MFR) of 50 minutes, wherein 50-70% of the carboxylic acid groups of the copolymer are neutralized to carboxylates containing potassium cations, sodium cations, or combinations thereof A composition comprising is disclosed. Articles and multilayer structures comprising this blend composition on a substrate, and methods for their preparation are also disclosed.

Description

  This application is filed on U.S. Patent Application No. 13 / 407,829, filed February 29, 2012, and U.S. Patent Application No. 13 / 407,858, filed Feb. 29, 2012. Claim priority to the specification.

  The present invention relates to compositions comprising ionomer-poly (vinyl alcohol) blends, aqueous dispersions and articles, methods of preparing them, and methods of forming a coating comprising the blend on a substrate.

  Ionomers of ethylene copolymers with α, β-ethylenically unsaturated carboxylic acids are known in the art, and at least some of the carboxylic acid groups of the copolymer are neutralized to produce alkali metals, alkaline earth metals or A carboxylate containing a transition metal cation is formed. US Pat. No. 3,264,272; US Pat. No. 3,338,739: US Pat. No. 3,355,319; US Pat. No. 5,155,157; US Pat. No. 5,244,969; U.S. Pat. No. 5,304,608; U.S. Pat. No. 5,542,677; U.S. Pat. No. 5,591,803; 688,869; U.S. Patent 6,100,336; U.S. Patent 6,245,858; U.S. Patent 6,518,365; and U.S. Patent Application Publication No. 2009. / 0297747.

  Aqueous dispersions of ionomers are also known in the art. U.S. Pat. No. 3,896,065; U.S. Pat. No. 3,904,569; U.S. Pat. No. 4,136,069; U.S. Pat. No. 4,508,804; No. 5,409,765; and Japanese Patent Application Publication Nos. 01009338 and 05075769. They dissolve the acid copolymer precursor in a solvent, neutralize the acid functionality, generally with ammonia, amines or alkali metal ions, dilute the solution in water, followed by partial or complete removal of the solvent. It is manufactured by. U.S. Pat. No. 2,313,144; U.S. Pat. No. 3,296,172; U.S. Pat. No. 3,389,109; U.S. Pat. No. 3,562,196; No. 5,430,111; U.S. Pat. No. 5,591,806; British Patent No. 1243303; and Japanese Patent Applications JP-A-50084687 and JP-A-200909426. I want.

  Aqueous ionomer dispersions are also made by heating the acid copolymer precursor or ionomer in hot aqueous ammonia and other neutralizing agents. For example, U.S. Pat. No. 3,644,258; U.S. Pat. No. 3,674,896; U.S. Pat. No. 3,823,108; U.S. Pat. No. 3,970,626; U.S. Pat. No. 4,540,736; U.S. Pat. No. 5,330,788; U.S. Pat. No. 5,550,177; U.S. Patent Publication No. 2007/0117916; See PCT Publication No. 06000872; PCT Patent Application Publication No. WO 2000/044801.

  Aqueous ionomer dispersions require the use of pressure vessels such as autoclaves and extruders, by dispersing the acid copolymer precursor in an aqueous solution of neutralizer at a temperature above the boiling point of water under high shear process conditions. Is also manufactured. For example, U.S. Pat. No. 4,775,713; U.S. Pat. No. 4,970,258; U.S. Pat. No. 4,978,707; U.S. Pat. No. 5,374,687; US Patent No. 5,445,893; US Patent No. 7279,513; US Patent No. 7,528,080; US Patent Application Publication No. 2005/0100754; US Patent Application Publication U.S. Patent Application Publication No. 2007/0124554; U.S. Patent Application Publication No. 2007/0141323; U.S. Patent Application Publication No. 2007/0144697; U.S. Patent Application Publication No. 2007/0292705; U.S. Patent Application Publication No. 2007. / 0295464; U.S. Patent Application Publication No. 2007/0295465; U.S. Patent Application Publication No. 2008/0. US Patent Application Publication No. 2008/0006602; US Patent Application Publication No. 2008/0041543; US Patent Application Publication No. 2008/0073045; US Patent Application Publication No. 2008/0073046 Specification: US Patent Application Publication No. 2008/0118728; US Patent Application Publication No. 2008/0135195; US Patent Application Publication No. 2008/0176968; US Patent Application Publication No. 2008/0182040 U.S. Patent Application Publication No. 2008/0216977; U.S. Patent Application Publication No. 2008/0230195; U.S. Patent Application Publication No. 2008/0292833; U.S. Patent Application Publication No. 2008/0295985; Patent Application Publication No. 2 No. 09/0194450; US Patent Application Publication No. 2009/0253321; European Patent Application Patent No. EP1163276; PCT Patent Application International Publication No. 2011-058119; International Publication No. 2011-058121; See International Publication No. 2011/068525 pamphlet; and Japanese Patent Application No. 2958120; Japanese Patent Laid-Open No. 10006640; and Japanese Patent Laid-Open No. 50135141.

  Aqueous ionomer dispersions are also made by dispersing ionomers in aqueous solutions at temperatures above the boiling point of water under high shear process conditions, requiring the use of pressure vessels such as autoclaves and extruders. U.S. Pat. No. 4,173,669; U.S. Pat. No. 4,329,305; U.S. Pat. No. 4,410,655; U.S. Pat. No. 4,440,908; See Japanese Patent Application No. 6,458,897; Japanese Patent Application Publication No. 11158332; Japanese Patent Application Publication No. 2000328046; Japanese Patent Application Publication No. 2005075878; and PCT Patent Application Publication No. International Publication No. 1999/10276.

  Aqueous ionomer dispersions are also made by dispersing highly neutralized, low melt index (MI) ionomers in hot water. See U.S. Pat. No. 3,321,819; U.S. Pat. No. 3,472,825 and U.S. Pat. No. 4,181,566.

  Ammonia neutralized ionomer aqueous dispersions have been used to coat certain substrates. For example, U.S. Pat. No. 3,872,039; U.S. Pat. No. 3,899,389; U.S. Pat. No. 3,983,268; U.S. Pat. No. 4,340,659; See U.S. Pat. No. 4,400,440; U.S. Pat. No. 4,714,728; U.S. Pat. No. 5,336,528 and U.S. Pat. No. 6,852,792. I want. As is well known in the art, ammonia neutralized ionomers release ammonia after drying to regenerate the parent acid copolymer and are not redispersible in hot water.

  Low molecular weight ionomer waxes are used as temporary coatings that can be removed with hot water. See, for example, US Pat. No. 5,292,794.

  Certain ionomer articles are dispersed in an aqueous caustic solution (US Pat. No. 6,162,852).

  Certain ionomer dispersions have been used as primer coatings for substrates such as PET, biaxially oriented polypropylene (BOPP) and aluminum foil films. For example, U.S. Patent No. 5,419,960; U.S. Patent No. 6,013,353; U.S. Patent No. 7,364,800; U.S. Patent No. 7,470,736; And U.S. Patent Application Publication No. 2005/0271888.

  Highly neutralized ionomer dispersions are used as fabric or paper treatment agents. See, for example, US Pat. No. 5,082,697; US Pat. No. 5,206,279; and US Pat. No. 5,387,635.

  Ionomer dispersions produced by autoclaving or extrusion processes are used as internal and external paper sizing agents or paper additives. For example, U.S. Patent No. 5,993,604; U.S. Patent No. 6,482,886; U.S. Patent No. 7,588,662; U.S. Patent Application Publication No. 2007/0137808; US Patent Application Publication No. 2007/0137809; US Patent Application Publication No. 2007/0137810; US Patent Application Publication No. 2007/0137811; US Patent Application Publication No. 2007/0137813; See published application 2007/0141936; published patent application 2007/0243331: and published patent application 2007/0284069.

  Certain ionomer dispersions are used in repulpable paper compositions. See, for example, US Pat. No. 5,160,484.

  Blends of aqueous ionomer dispersions and poly (vinyl alcohol) solutions are known in the art. For example, U.S. Pat. No. 3,674,896; U.S. Pat. No. 3,896,065; U.S. Pat. No. 4,547,456; U.S. Pat. No. 4,575,532; US Pat. No. 4,600,746; US Pat. No. 5,192,620; US Pat. No. 5,358,790; and US Pat. No. 6,821,373; European See Japanese Patent Application No. 886363; JP-A-09-124975; JP-A-2003-049035; and JP-A-60-072973. This blend has the disadvantage of a complex ionomer dispersion process as disclosed above.

  Ammonia-neutralized ionomer aqueous dispersions have been used to coat certain substrates. U.S. Pat. No. 3,872,039; U.S. Pat. No. 3,899,389; U.S. Pat. No. 3,983,268; U.S. Pat. No. 4,340,659; See U.S. Pat. No. 4,400,440; U.S. Pat. No. 4,714,728; U.S. Pat. No. 5,336,528; and U.S. Pat. No. 6,852,792. . As is well known in the art, ammonia-neutralized ionomers release ammonia after drying to regenerate the parent acid copolymer and are not redispersible in hot water.

  Low molecular weight ionomer waxes are used as temporary coatings that can be removed with hot water. See, for example, US Pat. No. 5,292,794.

  Certain ionomer articles are dispersed in an aqueous caustic solution (US Pat. No. 6,162,852).

  Certain ionomer dispersions have been used as primer coatings for substrates such as PET, biaxially oriented polypropylene (BOPP) and aluminum foil films. For example, U.S. Patent No. 5,419,960; U.S. Patent No. 6,013,353; U.S. Patent No. 7,364,800; U.S. Patent No. 7,470,736; And U.S. Patent Application Publication No. 2005/0271888.

  Highly neutralized ionomer dispersions are used as fabric or paper treatment agents. See, for example, US Pat. No. 5,082,697; US Pat. No. 5,206,279; and US Pat. No. 5,387,635.

  Ionomer dispersions produced by autoclaving or extrusion processes are used as internal and external paper sizing agents or paper additives. For example, U.S. Patent No. 5,993,604; U.S. Patent No. 6,482,886; U.S. Patent No. 7,588,662; U.S. Patent Application Publication No. 2007/0137808; US Patent Application Publication No. 2007/0137809; US Patent Application Publication No. 2007/0137810; US Patent Application Publication No. 2007/0137811; US Patent Application Publication No. 2007/0137813; See published application 2007/0141936; published patent application 2007/0243331: and published patent application 2007/0284069.

The present invention
(A) (i) 80-94 mol% hydrolysis and 15 centipoise (cp) 4 wt% aqueous viscosity at 20 ° C .; or (ii) 95 mol% -100 mol% hydrolysis. 99 to 1% by weight of a poly (vinyl alcohol) composition, based on the combination of (a) and (b), and (b) copolymerized units of ethylene, and a parent Based on the total weight of the acid copolymer, it comprises a parent acid copolymer comprising or consisting essentially of 18-30% by weight copolymer units of acrylic acid or methacrylic acid, which acid copolymer is used with a load of 2160 g Calculated for a non-neutralized parent acid copolymer having a melt flow rate (MFR) of 200-1000 g / 10 min measured according to ASTM D1238 at 190 ° C. Based on the total carboxylic acid content of the parent acid copolymer, 50-70% of the carboxylic acid groups of the copolymer are neutralized to carboxylates containing potassium cations, sodium cations, or combinations thereof. Based on the combination of a) and (b), it relates to a blend composition comprising or consisting essentially of 1 to 99% by weight of an ionomer composition.

  The present invention also includes an aqueous ionomer-poly (vinyl alcohol) comprising or consisting essentially of water and a combination of (a) and (b) described above from about 0.001 to about 50% by weight. ) Regarding dispersion.

The present invention is also a method for producing an aqueous ionomer-poly (vinyl alcohol) dispersion comprising a mixture of an ionomer composition and a poly (vinyl alcohol) composition comprising:
(1) providing an aqueous poly (vinyl alcohol) solution comprising or consisting essentially of water and the poly (vinyl alcohol) composition described in (a) above;
(2) providing an ionomer composition comprising or consisting essentially of the ionomer composition described in (b) above;
(3) mixing the ionomer composition with the aqueous poly (vinyl alcohol) solution, optionally with heating, to give a heated aqueous blend dispersion;
(4) a step of cooling the heated aqueous blend dispersion to a temperature of 20-30 ° C., wherein the combination remains dispersed in the liquid phase;
Comprise or consist essentially of,
The aqueous ionomer-poly (vinyl alcohol) dispersion provides a method as described above.

The present invention is also a method of forming a coating comprising a blend of ionomer and poly (vinyl alcohol) on a substrate comprising:
(1) preparing a blend composition as described above;
(2) a step of preparing a substrate;
(3) providing a method comprising, or consisting essentially of, coating the blend composition onto the substrate.

  In one embodiment, the blend composition is provided in the form of an aqueous dispersion comprising or consisting essentially of water and 0.001 to 50% by weight of a combination of (a) and (b); The blend composition is coated onto the substrate as an aqueous dispersion, and the method further includes the step of (4) drying the coated substrate at a temperature of 20-150 ° C.

  In another embodiment, the blend composition is provided in the form of a preformed film comprising or consisting essentially of a combination of (a) and (b); (3) is (3a) a substrate Creating a pre-laminate structure comprising a poly (vinyl alcohol) film layer adjacent; (3b) laminating the poly (vinyl alcohol) film layer to a substrate at a temperature of 50-150 ° C., optionally with applied pressure And the method further includes (4) cooling the coated substrate to a temperature of 20-30 ° C.

  The present invention also provides an article comprising or consisting essentially of the blend composition. The present invention also provides an article or multilayer structure comprising a coated substrate as described above.

  Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

  Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described herein.

  Unless otherwise noted, all percentages, parts, ratios, etc. are by weight.

  Where an amount, concentration, or other value or parameter is shown as a range, preferred range, or list of preferred values above and below preferred values, this is true regardless of whether the ranges are disclosed separately. It is to be understood that all ranges formed from any pair of any lower range limit or preferred value and any upper range limit or preferred value are specifically disclosed. When numerical ranges are listed herein, unless otherwise specified, the ranges are intended to include the endpoints and all integers and fractions within the ranges. It is not intended that the scope of the invention be limited to the specific values recited when defining a range.

  As used herein, "comprises", "comprising", "includes", "including", "containing", "containing" “Characterized by”, “has”, “having” or any other variation thereof is intended to cover non-exclusive inclusions. For example, a process, method, article, or device that includes an enumeration of components is not necessarily limited to only those components, and is not explicitly listed or such a process, method, article, Alternatively, other components inherent in the apparatus may be included. Further, unless otherwise explicitly stated, “or” refers to inclusive OR and not exclusive OR.

  The transitional phrase “consisting essentially of” extends the scope of the claims to those that do not materially affect the specified material or process and the basic and novel features or characteristics of the claimed invention. limit. When the applicant defines the present invention or a part thereof in an open-ended term such as “comprising”, the description “consists essentially of”, unless otherwise specified. Should be construed to describe such invention using the term.

  The use of “a” or “an” is used to describe the components and components of the invention. This is merely for convenience and to give a general sense of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

  In describing certain polymers, it is understood that Applicants may refer to a polymer by the monomer used to make the polymer, or the amount of monomer used to make the polymer. Should be. Such descriptions may not include the specific nomenclature used to describe the final polymer or may not include product-by-process terms, but may include Any such reference should be construed to mean that the polymer includes copolymerized units of those monomers or their amounts of monomers, and their corresponding polymers and compositions.

  The term “copolymer” is used to refer to a polymer formed by the copolymerization of two or more monomers. Such copolymers include dipolymers consisting essentially of two copolymerized comonomers.

  As used herein, “disperse”, “dispersing” and related terms are used when solid articles such as polymer pellets are mixed with water in a short period of time. The process that disappears in the liquid phase. The terms “aqueous dispersion” and “dispersion” describe a free flowing liquid that is free of human visible solids. No characterization is performed with respect to the interaction of polymer molecules that readily disperse in high temperature (80-100 ° C.) water without the need for additional dispersants or reactants.

  Viscosity is a measure of the resistance of a fluid to shear due to shear stress. In common terms just for fluids, viscosity may be thought of as “thickness” or “internal friction”. For example, water has a relatively low viscosity and is “thin”, while molasses has a relatively high viscosity and is “thick”. The lower the viscosity of the fluid, the greater the ease of movement (fluidity). As used herein, viscosity refers to dynamic or absolute viscosity.

  As used herein, the terms “poly (vinyl alcohol)” and “PVOH” generally refer to poly (vinyl alcohol) homopolymers or copolymers unless specified in more detail.

  The coating methods described herein provide a coated substrate using a blend composition comprising an ionomer and some poly (vinyl alcohol). An ionomer-poly (vinyl alcohol) coating on a substrate as disclosed herein may be in the form of a monolithic membrane that functions as a barrier to fluid penetration into or through the substrate. The monolithic membrane has a high water penetration pressure, is waterproof and liquidproof. This coating also makes it possible to provide a heat-sealable surface on a non-heat-sealable substrate. Printability can be improved by changing the surface of the paper with the coating to make it more hydrophilic.

  Articles comprising this coated substrate provide readily recyclable commercial articles, for example by repulping coated paper, paperboard and the like.

Poly (vinyl alcohol) composition Blends and aqueous dispersions are poly (vinyl alcohol)
(I) a poly (vinyl alcohol) characterized by a degree of hydrolysis of 80 to 94 mol% and a 4 wt% aqueous viscosity of 15 centipoise (cP) or less; or (ii) a degree of hydrolysis of 95 mol% to 100 mol% A poly (vinyl alcohol) composition comprising, or consisting essentially of.

  The combination of the degree of hydrolysis and the 4 wt% aqueous viscosity of the poly (vinyl alcohol) composition provides the desired solubility / dispersibility required to form an aqueous dispersion when blended with an ionomer.

  The poly (vinyl alcohol) composition can be obtained by a known and conventional method. Poly (vinyl alkyl) compositions typically undergo polymerization of vinyl acetate monomers followed by alcoholysis or hydrolysis of the as-made poly (vinyl acetate) composition into a poly (vinyl alcohol) composition. Obtained by transformation through a decomposition process. Strictly speaking, the alcoholysis is carried out with a basic catalyst in alcohol as the reaction medium, resulting in the corresponding alkyl acetate and poly (vinyl alcohol) units. Hydrolysis in water generally uses large amounts of a metal caustic base and results in metal acetate rather than poly (vinyl alcohol) units and the corresponding alkyl acetate. The formation of metal salts, ie acetates, has led to the use of the term “saponification” for this process, similar to the formation of metal salts of fatty acids and caustic in the manufacture of soaps. When aqueous alcohol is used as the reaction medium, both hydrolysis and alcoholysis can occur. However, in U.S. Pat. No. 2,940,948, alcohol degradation rather than hydrolysis occurs under certain circumstances, even with aqueous alcohol. The difference depends strictly on the reaction product, while the term has tended to be used rather than strict. Poly (vinyl alcohol) products are typically referred to as “hydrolyzed” or “saponified”.

  If not all of the acetate groups are completely converted to alcohol groups, the terms “partially hydrolyzed”, “partially saponified”, and “moderately hydrolyzed” are used. It is common. If the poly (vinyl acetate) homopolymer is simply partially hydrolyzed, the resulting poly (vinyl alcohol) is actually a vinyl alcohol / vinyl acetate copolymer. However, as stated, such polymers are generally referred to as partially hydrolyzed poly (vinyl alcohol) homopolymers. Commercially, the term partially hydrolyzed is typically used for PVOH having a degree of hydrolysis of 86-89%, and the term moderately hydrolyzed is 89-98% hydrolysis. Used for PVOH with a degree. For less than 86% hydrolysis, there is no standard terminology, but “sub-partially hydrolyzed” is used. However, for simplicity of explanation, the term “partially hydrolyzed” is used herein for PVOH having a degree of hydrolysis of 80-94 mol%.

  Surprisingly, the inventors have found that some partially hydrolyzed poly (vinyl alcohol) compositions when combined with the ionomer described below are aqueous under mild conditions as described herein. It was found to give a dispersion. The degree of hydrolysis of the poly (vinyl alcohol) composition useful in preparing such an aqueous dispersion is 80 to 94 mol%, preferably 85 to 93 mol%, more preferably 87 to 90 mol%. There may be.

  The viscosity of poly (vinyl alcohol) as a 4 wt% aqueous solution at 20 ° C. serves as an industry standard for the degree of polymerization and average molecular weight of the poly (vinyl alcohol) polymer.

  The 4 wt% aqueous viscosity at 20 ° C. of the partially hydrolyzed poly (vinyl alcohol) composition may be 15 centipoise (cP) or less, preferably 1 to 15 cP, or 7 cp or less. Of note are partially hydrolyzed poly (vinyl alcohols) having a 4 wt% aqueous viscosity at 20 ° C. from the lower limit of 1, 2 or 4 cP to the upper limit of 7, 10 or 15 cP. Certain partially hydrolyzed poly (vinyl alcohols) have a degree of hydrolysis of 87-89% and a 4 wt% aqueous viscosity at 20 ° C of 5-6 cP, 8-10 cP or 11-14 cP.

  An aqueous solution containing 5-20% by weight of such poly (vinyl alcohol) composition may have a viscosity at 20 ° C. of 5-2000 cp, or higher.

  Surprisingly, the inventors have found that highly hydrolyzed poly (vinyl alcohol) compositions when combined with the ionomers described below are aqueous under mild conditions as described herein. It was also found to give a dispersion. As used herein, “highly hydrolyzed” is 95 mol% to 100 mol%, such as 95 to 97 mol%, or 95 to 99 mol%, or 97 to 99 mol%, or Refers to a poly (vinyl alcohol) polymer having a degree of hydrolysis greater than 98 mol%. Poly (vinyl alcohol) having a degree of hydrolysis of 98 mol% or higher is also described herein as “fully hydrolyzed”.

  Certain poly (vinyl alcohols) have a degree of hydrolysis of 95-97% and a 4 wt% aqueous viscosity at 20 ° C of 25-30 cP, or a degree of hydrolysis of more than 99% and 4 at 20 ° C of 27-33 cP. Has a weight percent aqueous viscosity.

  An aqueous solution containing 5 to 16% by weight of such poly (vinyl alcohol) composition may have a viscosity at 20 ° C. of 35 to 10,000 cp or more.

  Poly (vinyl alcohol) copolymers may also be useful for forming aqueous dispersions with ionomers provided that they have the hydrolysis and viscosity attributes described above. In this regard, the term “copolymer” refers to substances resulting from hydrolysis of vinyl acetate copolymers that also contain units derived from monomers other than vinyl acetate, such as alkyl acrylate, including methyl acrylate or methyl methacrylate. As used herein.

  The poly (vinyl alcohol) composition may also contain other additives known in the art. Additives include but are not limited to processing aids, flow enhancing additives, lubricants, pigments, dyes, flame retardants, impact modifiers, nucleating agents, anti-blocking agents (such as silica), Thermal stabilizers, UV absorbers, UV stabilizers, surfactants, chelating agents, and / or coupling agents may be included.

Ionomer Composition As used herein, an ionomer comprises copolymerized units of ethylene and copolymerized units of 18-30 wt% α, β-ethylenically unsaturated carboxylic acid, such as acrylic acid or methacrylic acid. Derived from certain parent acid copolymer containing. Preferably, the parent acid copolymer used herein comprises 19-25% by weight, more preferably 19-23% by weight of an α, β-ethylenically unsaturated carboxylic acid, based on the total weight of the copolymer. .

  Preferably, the α, β-ethylenically unsaturated carboxylic acid is methacrylic acid. In particular, an acid copolymer consisting essentially of copolymerized units of ethylene, copolymerized units of α, β-ethylenically unsaturated carboxylic acid, and 0% by weight of additional comonomer; ie, ethylene and α, β-ethylene Of note are dipolymers of the unsaturated unsaturated carboxylic acids. A preferred acid copolymer is an ethylene methacrylic acid dipolymer.

  The parent acid copolymers used herein are described in US Pat. No. 3,404,134; US Pat. No. 5,028,674; US Pat. No. 6,500,888; It may be polymerized as disclosed in US Pat. No. 6,518,365.

  The parent acid copolymer used herein preferably has a melt flow rate (MFR) of 200 to about 1000 grams / 10 minutes as measured according to ASTM D1238 at 190 ° C. using a load of 2160 g. Alternatively, the parent acid copolymer has an MFR from a lower limit of 200, 250 or 300 to an upper limit of 400, 500, 600 or 1000. The preferred melt flow rate of the parent acid copolymer provides an ionomer that allows rapid self-dispersion in hot water. Ionomers derived from a parent acid copolymer having a melt flow rate of less than 200 grams / 10 minutes have minimal hot water self-dispersibility while being derived from a parent acid copolymer having a melt flow rate of greater than 1000 grams / 10 minutes. The ionomer can reduce physical properties in the intended end use.

  In some embodiments, blends of two or more ethylene acid copolymers may be used, provided that the aggregate components and properties of the blend fall within the ranges described above for ethylene acid copolymers. To do. For example, two ethylene methacrylic acid dipolymers are used so that the total weight percent of methacrylic acid is 18-30 weight percent of the total polymer material and the melt flow rate of the blend is 200-1000 grams / 10 minutes. May be.

  The ionomers disclosed herein are calculated for a non-neutralized parent acid copolymer, 50-70%, preferably 55-60%, for example 59-60%, of the total carboxylic acid groups of the parent acid copolymer, Produced from a parent acid copolymer that is neutralized to form a carboxylate salt with sodium ions, potassium ions, or mixtures thereof. The parent acid copolymer may be neutralized using, for example, the method disclosed in US Pat. No. 3,404,134. Preferably, the ionomers disclosed herein are generated from a parent acid copolymer in which the carboxylic acid group of the parent acid copolymer is neutralized to form a sodium ion and carboxylate.

  Importantly, ionomer compositions combine the properties of being thermoplastic and self-dispersing in high temperature water. Preferably, the ionomer used herein has a melt flow rate (MFR) of at least 1 gram / 10 minutes, such as 1-20 grams / 10 minutes, measured according to ASTM D1238 at 190 ° C. using a load of 2160 g. ). More preferably, the ionomer composition has an MFR of 10 grams / 10 minutes, most preferably 1-5 grams / 10 minutes. The combination of melt flow rate and degree of neutralization of the parent acid copolymer provides an ionomer that combines the properties of being easily self-dispersible in high temperature water and easily melt processable into commercial articles. To do. Preferably, the ionomer composition comprises at least 11% by weight methacrylate and has an MFR of at least 1 g / 10 min.

  In some embodiments, a blend of two or more ionomers may be used, provided that the aggregate components and properties of the blend fall within the limitations described above for the ionomer.

  An aqueous dispersion containing 5-20% by weight of such an ionomer may have a viscosity at 23 ° C. of 1-30 cp.

  The ionomer composition may contain other additives known in the art. Additives include, but are not limited to, processing aids, flow enhancing additives, lubricants, pigments, dyes, flame retardants, impact modifiers, nucleating agents, antiblocking agents. (Such as silica), thermal stabilizers, UV absorbers, UV stabilizers, surfactants, chelating agents, and coupling agents may be included.

Blend Compositions PVOH and ionomers can be combined into blend compositions, including aqueous dispersions. The blend composition comprises or consists essentially of a combination of 1-99% by weight poly (vinyl alcohol) composition and 99-1% by weight ionomer composition, wherein the ionomer and poly (vinyl alcohol) are , As described above.

  It should be noted that the ionomer is present in the combination in an amount from the lower limit of 10, 20, 30, 40 or 50% by weight to the upper limit of 60, 70, 80, 90 or 95% by weight and the poly (vinyl alcohol) is , A composition present in complementary amounts. It should also be noted that the ionomer is present in the combination in an amount from the lower limit of 60, 70, or 75 wt% to the upper limit of 80, 85, 90, or 95 wt%, and the poly (vinyl alcohol) is in a complementary amount. It is an existing composition.

  Preferably, the ionomer and PVOH may be blended in an aqueous dispersion as disclosed in more detail below, which avoids heating the PVOH beyond its melting point. Preferably the pH of the aqueous dispersion is greater than 8.5. Below a pH of 8.5, the ionomer is not well dispersed. The aqueous blend dispersion can then be processed to a solid by drying (removing water) to give the article. For example, an aqueous blend dispersion may be formed into a cast film by forming a thin layer of an aqueous blend followed by drying.

  The ionomer-PVOH composition may also contain other additives known in the art. Additives include but are not limited to processing aids, flow enhancing additives, lubricants, pigments, dyes, flame retardants, impact modifiers, nucleating agents, anti-blocking agents (such as silica), Thermal stabilizers, UV absorbers, UV stabilizers, surfactants, chelating agents, and coupling agents may be included.

  The blend composition article may take any desired physical form, such as powders, pellets, melt cut pellets, coatings, films, sheets, molded articles, and the like.

Dispersion Method A method for producing an aqueous ionomer-poly (vinyl alcohol) dispersion comprising a mixture of an ionomer composition and a poly (vinyl alcohol) composition comprises:
(1) providing water and an aqueous poly (vinyl alcohol) solution comprising or consisting essentially of the poly (vinyl alcohol) composition described in (a) above;
(2) providing an ionomer composition comprising or consisting essentially of the ionomer composition described in (b) above;
(3) mixing the ionomer composition with the aqueous poly (vinyl alcohol) composition solution, optionally with heating;
(4) the heated aqueous blend dispersion may be cooled to a temperature of 20-30 ° C., the combination comprising or consisting essentially of remaining dispersed in the liquid phase ,
And the aqueous ionomer-poly (vinyl alcohol) dispersion is as described above.

  The dispersion methods described herein surprisingly require less energy than prior art dispersion processes, and have very mild process conditions, such as low shear (e.g., heated poly A mixture of (vinyl alcohol) and ionomer is simply stirred, either as a solid or as an aqueous dispersion, and poly (vinyl alcohol) under relatively low temperature (at atmospheric pressure and below the boiling point of water) Enables the production of aqueous dispersions in combination with ionomers. This dispersion method is essential by the use of a preformed blend composition by allowing the avoidance of strong bases such as aqueous sodium hydroxide (caustic), aqueous potassium hydroxide or ammonia during the dispersion process. To provide a more secure distributed process.

  Strictly speaking, the blend composition generally comprises a solution of a poly (vinyl alcohol) composition, and a dispersion of an ionomer composition, hereinafter referred to as a dispersion for simplicity.

  The aqueous poly (vinyl alcohol) solution may be prepared by any method disclosed in the art. In general, such a process forms a mixture of PVOH compositions in water at a temperature between 20 ° C. and 30 ° C., and subsequently the mixture is dissolved until the PVOH composition dissolves to form an aqueous PVOH composition solution. Including heating at a temperature and for a period of time. The water solubility temperature of PVOH generally depends on the degree of hydrolysis of a particular PVOH composition. For PVOH compositions having a degree of hydrolysis of 89 mol% or less, the water dissolution temperature can generally range from 20 ° C to 40 ° C. For PVOH compositions having a degree of hydrolysis in the range of 90 mol% to 97 mol%, the water dissolution temperature can generally be in the temperature range of 40 ° C to 60 ° C. For PVOH compositions having a degree of hydrolysis in the range of greater than 97 mol%, the water dissolution temperature may generally be in the temperature range of 60C to 100C. In order to prepare the solution faster, it may be useful to heat the mixture of water and PVOH at a temperature above the threshold temperature for dissolution. For example, the water-PVOH mixture may be heated to 90-95 ° C. regardless of the degree of hydrolysis.

  The poly (vinyl alcohol) solution may be produced in any suitable container, such as a tank, vat, basket, etc. Stirring is important to provide effective contact between the bulk solid poly (vinyl alcohol) composition and water as dissolution proceeds to avoid PVOH clamping. The solution may be produced for about 1 hour at 90 ° C. for a batch process.

  Alternatively, it is further contemplated that the dissolution process may be performed in a continuous process. For example, a continuous or “jet” digester can be used, wherein the suspension of polyvinyl alcohol is mixed with water vapor in a sealed tube under pressure, completely dissolved, or of polyvinyl alcohol. Depending on the particle size, exit the pressure tube section at a high enough temperature to complete the dissolution process in minutes.

  The aqueous poly (vinyl alcohol) solution preferably has a poly (vinyl alcohol) with a lower limit of 0.1 or 1% to an upper limit of 10, 20, 30 or 50% by weight, based on the total weight of the blend composition and water. Make up the composition.

  In some embodiments, the dispersion method includes providing a preformed aqueous solution of the poly (vinyl alcohol) composition and mixing it with the preformed aqueous dispersion of the ionomer composition. The aqueous ionomer dispersion is mixed with water heated to a temperature of 80-100 ° C. (under low shear conditions) to give a heated aqueous ionomer composition dispersion, followed by cooling to a temperature of 20-30 ° C. In which the ionomer remains dispersed in the aqueous phase.

  An aqueous dispersion of an ionomer composition can be produced, for example, by contacting a solid ionomer composition in the form of melt cut pellets with water at a temperature of 80-100 ° C. In some embodiments, the temperature is in the range of 85-90 ° C. Surprisingly, the ionomer compositions described herein can be dispersed in water at 80-100 ° C., lower than expected based on the prior art, and require significantly less energy. do not do. However, it will be appreciated that even though the ionomer compositions are dispersed in that temperature range, they can be dispersed at temperatures in excess of 100 ° C.

  The ionomer dispersion may be produced in any suitable container, such as a tank, vat, jar, and the like. Agitation is useful to provide effective contact of the bulk solid ionomer composition with water as the dispersion proceeds. Preferably, the dispersion is produced in about 1 hour or less, eg, 30 minutes or 20 minutes or less. The smaller the particle size of the solid ionomer, the shorter the dispersion time. Surprisingly, due to the rapid dispersibility of the ionomer composition, the dispersion components proceed as they travel through the pipeline where they are introduced at one end of the pipeline and as they travel down the length of the pipeline. It is further contemplated that may be formed. For example, the ionomer composition may be mixed with water and passed through a heating zone, such as a static mixer, with or without additional mixing. Alternatively, the ionomer composition may be mixed with hot water and passed through a pipeline, eg, a static mixer, with or without additional mixing.

  In one embodiment, the ionomer composition is mixed with water under low shear conditions at room temperature (20-25 ° C.) and the temperature is raised to 80-100 ° C. In another embodiment, the ionomer composition is mixed with water under low shear conditions at room temperature and the temperature is raised to 85 ° C to 90 ° C.

  In another embodiment, the ionomer composition is mixed with water preheated to a temperature of 80-100 ° C. under low shear conditions. In another embodiment, the ionomer composition is mixed under low shear conditions with water preheated to a temperature of 85-90 ° C.

  The aqueous dispersion of ionomer preferably comprises the ionomer in an amount from the lower limit of 0.001 or 1% to the upper limit of 10, 20, 30 or 50% by weight of the total weight of ionomer and water. Preferably, the pH of the aqueous dispersion is greater than 8.5. Below a pH of 8.5, the ionomer is not well dispersed.

  Once prepared, the aqueous poly (vinyl alcohol) solution and the aqueous ionomer dispersion may be mixed together by any suitable means, with or without additional heating. In some cases, aqueous poly (vinyl alcohol) solutions and aqueous ionomer dispersions may be maintained at or near the high temperatures required for their preparation by a mixing process. The resulting aqueous blend may be used in further operations at the high temperatures required for its preparation. Alternatively, the resulting aqueous blend may then be cooled to ambient temperature (20-30 ° C.) for storage or subsequent use.

  The blend dispersion may also be prepared by mixing the aqueous PVOH solution with the aqueous ionomer dispersion both at 20-30 ° C. either before or through the mixing step.

  The order in which the aqueous PVOH solution and aqueous ionomer dispersion are mixed is not critical, provided that the PVOH is in the form of an aqueous solution prior to mixing with the ionomer dispersion. For example, the PVOH solution may be prepared in a suitable container and the separately prepared aqueous ionomer dispersion is then added to the container. Mixing can take place in any suitable mixing vessel, such as a tank, vat, jar, and the like. Agitation can be useful to provide sufficiently rapid mixing of the poly (vinyl alcohol) and ionomer dispersion. Mixing proceeds in a pipeline where the components of the PVOH solution and ionomer dispersion of the blend dispersion are charged at one end of the pipeline, with or without additional mixing, for example, through a static mixer. Thus, a blend may be formed as it proceeds down the length of the pipeline.

  In other embodiments, solid forms of ionomers, such as melt cut pellets, may be mixed with an aqueous poly (vinyl alcohol) solution by heating to prepare a blend dispersion.

In one such embodiment, the method comprises
(1) heating a mixture of water and the poly (vinyl alcohol) composition described above to give an aqueous poly (vinyl alcohol) solution;
(2) the ionomer composition comprising or essentially consisting of the ionomer described above is in solid form;
And mixing in step (3)
(A) heating the aqueous poly (vinyl alcohol) solution to a temperature of 80-100 ° C. (under low shear conditions);
(B) contacting the solid ionomer composition with a heated aqueous poly (vinyl alcohol) solution;
(C) continuing heating at a temperature of 80-100 ° C. (under low shear conditions) until the solid ionomer composition is completely dispersed;
(4) comprising or consisting essentially of a step that may be cooled to a temperature of 20 to 30 ° C;
The aqueous ionomer-poly (vinyl alcohol) dispersion is as described above.

In another such embodiment, the method comprises:
(1) heating a mixture of water and the poly (vinyl alcohol) composition described above to give an aqueous poly (vinyl alcohol) solution;
(2) the ionomer composition comprising or consisting essentially of the ionomer described above is in solid form;
And the mixing in step (3)
(D) contacting the solid ionomer composition with an aqueous poly (vinyl alcohol) solution to provide a mixture;
(E) heating the mixture to a temperature between 80 ° C. and 100 ° C. (under low shear conditions) until the solid ionomer composition is completely dispersed;
(4) comprising or consisting essentially of a step that may be cooled to a temperature of 20-30 ° C.
The aqueous ionomer-poly (vinyl alcohol) dispersion is as described above.

  The order of mixing the aqueous PVOH solution and the solid ionomer dispersion is not critical, provided that the PVOH is in the form of an aqueous solution prior to mixing with the ionomer. For example, the PVOH solution may be prepared in a suitable container and the solid ionomer is subsequently added to the container.

  Mixing can take place in any suitable mixing vessel, such as a tank, vat, jar, and the like. Agitation can be useful to provide sufficiently rapid mixing of the poly (vinyl alcohol) and ionomer dispersion. The smaller the particle size of the solid ionomer, the shorter the dispersion time. Mixing proceeds in a heated pipeline where the PVOH solution and ionomer components of the blend dispersion are charged at one end of the pipeline, with or without additional mixing, for example, through a static mixer. A blend may be formed as it travels down the length of the pipeline.

  If necessary, additional water may be added after initial mixing to give a dispersion having a relatively low concentration of PVOH and ionomer. For example, a concentrated dispersion may be prepared, stored for a period of time, and then diluted with water to give a dispersion having a relatively low concentration when used.

  The dispersion may contain other additives known in the art. For example, the composition may include wax additives, such as microcrystalline wax or polyethylene wax, which not only improve the coefficient of friction but also function as an antiblocking agent. Other types of additives include fumed silica (which reduces the sticking of the blend composition at room temperature), fillers, crosslinkers, antistatic agents, antifoaming agents, dyes, brighteners, processing aids. Includes flow improvers, lubricants, dyes, pigments, flame retardants, impact modifiers, nucleating agents, anti-blocking agents, thermal stabilizers, UV absorbers, UV stabilizers, chelating agents, coupling agents, etc. It is.

  Inorganic fillers include calcium carbonate, titanium dioxide, silica, talc, barium sulfate, carbon black, ceramics, chalk or mixtures thereof. Clay filler, natural clay, synthetic clay, treated clay, untreated clay, organic clay, smectite clay, bentonite clay, hectorite clay, wollastonite clay, montmorillonite clay, kaolin, or mixtures thereof. Organic fillers include natural starch, modified starch, chemically modified starch, rice starch, corn starch, wood flour, cellulose, and mixtures thereof.

  Starch is a natural product composed of various amounts of amylose and amylopectin. As used herein, “starch” generally refers to starch, starch derivatives, modified starch, thermoplastic starch, cationic starch, anionic starch, starch esters (such as starch acetate), starch hydroxyethyl ether, alkyl Refers to starch, amine starch, phosphate starch and dialdehyde starch. Important plant sources of starch used in the paper industry are potato, barley, wheat corn, waxy maize (corn without amylose in starch) and tapioca. Starch can be modified in several ways. Starch viscosity can be reduced using enzymes, heat treatment, ammonium persulfate, hypochlorite, or acids. Furthermore, starch can be chemically modified, for example, by hydroxyethylation, carboxymethylation, acetylation, or phosphating. Thermoplastic starch may be produced, for example, as disclosed in US Pat. No. 5,362,777, for which starch has little or no crystallinity and has a low glass transition. It has been disclosed to mix and heat natural or modified starch with a high boiling plasticizer such as glycerin or sorbitol so as to have temperature and low water content. Preferably, the starch does not include high viscosity ethoxylated (or “ethylated”) starch.

  Once prepared, the ionomer-PVOH composition may be coated on a substrate as described below.

Substrate Material A substrate is any material that provides support, shape, aesthetic effect, protection, surface texture, bulk volume, weight, or a combination of two or more thereof that enhances the functionality and handleability of the structure. May be. Essentially any substrate material known in the art may be used.

  Any support or substrate that meets these desired properties may be used with the ionomer-PVOH composition. For example, cellulosic materials such as paper webs (eg kraft paper or rice paper), materials made from synthetic fiber spun fabrics, non-woven textiles, films, open cell foams, closed cell foams, microporous films, or even A perforated film having a large percentage of open areas, such as a perforated PE film, may be used as the material for the substrate. Metal foils such as aluminum foil may also be used as the substrate.

Cellulosic materials include paper, paperboard, cardboard, and pulp molding. Paper, paperboard, cardboard, etc. refer to physical forms derived from cellulose or its derivatives that are treated as pulp and formed into sheets by heat and / or pressure. Paper represents a thin sheet made from cellulose pulp that is somewhat soft or semi-rigid. In general, paperboard and cardboard are thicker and harder sheets or structures based on paper. Typically, paperboard is defined as paper with a basis weight of greater than 224 g / m ^2. According to the present disclosure, the paper layer or paperboard layer used in the substrate may have a thickness of about 30-600 μm and a basis weight of 25-500 g / m ² , or 100-300 g / m ² . The cardboard can be a monolithic sheet or can have a more complex structure such as corrugations. Corrugated paper includes a sheet of corrugated paper that is sandwiched between two flat sheets of paper. The coating of ionomer-PVOH blend may be useful as an adhesive for making corrugated board. Pulp moldings are typically non-planar moldings in which cellulose pulp is formed into a rigid molding by the application of pressure and / or heat. An example of a pulp molding is an egg carton.

  Examples of substrates also include textiles or porous sheet materials. Textiles may include nonwoven textiles prepared from polypropylene, polyethylene, polyesters such as polyethylene terephthalate, or mixtures thereof, and other spunbond polymer fabrics. Sheets made from synthetic fiber spun fabrics such as nonwoven textiles may be used as the textile substrate. Crosses, such as woven or knitted, are also suitable as textile substrates. Natural fibers alone or in combination with man-made fibers can also be used in the textile substrate. The fabric may include flame retardants, fillers, or additives disclosed above.

  The base material may be in the form of a film, a sheet, a woven fabric, a non-woven fabric or the like. The substrate material may be unoriented or uniaxially or biaxially oriented. The substrate material may comprise a polymer or metal composition. The substrate may be treated, for example, to enhance adhesion with the coating. This treatment may be, for example, adhesive, primer or coupling agent treatment, or surface treatment such as chlorination, flame treatment (eg, US Pat. No. 2,632,921; US Pat. No. 2,648,097). U.S. Pat. No. 2,683,894; and U.S. Pat. No. 2,704,382), plasma treatment (e.g. U.S. Pat. No. 4,732,814). In the art such as electron beam treatment, oxidation treatment, chemical treatment, chromic acid treatment, hot air treatment, ozone treatment, ultraviolet treatment, sandblast treatment, solvent treatment or corona treatment, and combinations of the above It may take any known form.

  Specific examples of the base material include poly (ethylene terephthalate) (PET) film, biaxially oriented poly (propylene) (BOPP) film, polyamide film, aluminum foil, paper, paperboard and the like. Preferably, the substrate material is paper, paperboard or the like that allows repulping after use.

  The substrate material may be of any thickness, but is generally in the range of 0.1-20 mils, more typically 0.5-10 mils.

  A method of forming a coating comprising a blend of ionomer and poly (vinyl alcohol) on a substrate provides a blend composition comprising (or consisting essentially of) PVOH and an ionomer as described above. Comprising, or consisting essentially of: (2) providing a substrate as described above; and (3) coating the blend composition onto the substrate.

  Coating methods include embodiments in which the blend composition is in the form of an aqueous dispersion, extrusion coating in which the blend composition is in molten form, and lamination methods in which the blend composition is in the form of a preformed film.

Dispersion Coating Method One embodiment of the coating method is an aqueous ionomer comprising or consisting essentially of water and a combination of (a) and (b) described above from 0.001 to 50% by weight It is in the form of a poly (vinyl alcohol) dispersion. In this embodiment, the preparation of the blend composition may comprise or consist essentially of the dispersion method described above. This embodiment further includes the step of (4) drying the coated substrate at a temperature of 20 to 150 ° C.

  In some embodiments, the polymer composition can be coated directly onto the substrate using impregnation and coating techniques. For example, the ionomer-PVOH composition may be a coating that is applied directly onto the substrate (by spraying, painting or other suitable application method). Such a coating may be applied by a rubber doctor blade using a spreading method known in the art.

  The composition may be applied to one or both sides of the substrate. When the substrate is coated or laminated on one side, the composition is applied to the side that is directly exposed to the environment to provide a liquid-impermeable outer surface. Alternatively, in applications where there may be mechanical wear or abrasion, the composition is applied to the surface of the substrate opposite the surface exposed to mechanical wear to provide protection of the polymer composition. May be.

  In other embodiments, the composition can be impregnated into the substrate, or the substrate can be impregnated into the polymer.

  The ionomer-PVOH composition is impregnated into the substrate by impregnating the substrate with the coating composition as an aqueous dispersion and then drying the composition while still in contact with the pores of the substrate. It may be at least partially formed.

  The composition can be dispersed throughout the substrate, such as a loosely woven fabric, if the composition fills the voids in the substrate and does not only adhere to the surface of the substrate. The substrate can be impregnated within the ionomer-PVOH composition by a coating process to have the ionomer-PVOH composition on both sides of the substrate.

  Coating as an aqueous dispersion can be any known in the art including gravure coating, curtain coating, blade coating, air knife coating, roll coating, wire rod coating, dip coating, flexographic printing, spray coating, etc. Can be applied to the substrate in any suitable manner. Excess aqueous dispersion coating composition can be removed with a squeeze roll, doctor knife, etc., if desired.

  In the case of preferred paper and paperboard substrates, the substrate is, for example, a paddle size press, a metering size press, a vertical size press, a slanted size press and as described above or during the manufacture of a paper or paperboard substrate. Applied to preformed paper or paperboard substrate using size press such as horizontal size press, roll coater, gate roll coater, blade coater, bill blade coater, and sprayer and coated on paper or paperboard substrate The composition may be coated.

  After coating the substrate, the aqueous dispersion is dried to give a solid coating of ionomer-PVOH blend on the substrate. As used herein, “drying” means removing water from an aqueous dispersion, for example, by evaporation, lyophilization, and the like. Drying may include drying the dispersion under ambient conditions (temperature of 20-30 ° C. and atmospheric pressure). Alternatively, drying may include application of elevated temperature (eg, up to 100 ° C. in an oven or heated tunnel) and / or reduced pressure. Freeze drying includes rapid freezing and drying in a high vacuum. Barrier properties may be improved when the coating is dried in a manner in which the dried ionomer is heated above about 85 ° C.

Non-dispersive coating method Another embodiment is that the blend composition is in the form of a preformed film. In this embodiment, the present invention is a method of forming a coating comprising an ionomer and PVOH on a substrate comprising:
(A) providing a preformed film of an ionomer-PVOH composition as described above;
(B) creating a prelaminate structure comprising an ionomer-PVOH film layer adjacent to the substrate layer;
(C) laminating the ionomer film layer to the substrate layer at a temperature of 50 to 150 ° C., optionally with applied pressure;
(D) cooling the coated substrate to a temperature of 20-30 ° C., or providing a method consisting essentially of them.

  The preformed film of the ionomer-PVOH composition may be made by any known technical method. For example, thin films may be made by dip coating; by preparing a thin layer of aqueous ionomer-PVOH dispersion followed by drying or by any other process known to those skilled in the art.

  In the film lamination method, the ionomer-PVOH coating layer can be included in a multilayer structure along with one or more layers of additional material to provide a multilayer coating. In such a process, the ionomer-PVOH coating layer may be applied such that it is in direct contact with the substrate or it is an intervening layer between the substrate and the ionomer-PVOH layer. It may be applied in contact with.

  The actual manufacture of the multilayer film and corresponding film structure can be by any method as is generally practiced in the art. Thus, films and film structures used as substrates for ionomer-PVOH compositions are typically oriented by various methodologies (eg, blown film, bubble technology, mechanical stretching, etc., or lamination) ( Casting, extrusion, coextrusion, etc., including either axial or biaxial). Various additives as commonly practiced in the art, including the presence of tie layers, etc. (provided that their presence does not substantially alter the properties of the film or film structure), It should be understood that each film layer can be present. Accordingly, various additives such as, for example, antioxidants and heat stabilizers, ultraviolet (UV) light stabilizers, pigments and dyes, fillers, anti-slip agents, plasticizers, other processing aids are advantageously used. It is contemplated that it may be.

  A preformed film of ionomer-PVOH composition can be applied to one or both sides of the substrate. Preferably, the ionomer-PVOH composition layer is about 0.1 mils to 20 mils thick, more preferably 0.3 mils to 10 mils thick, most preferably 0.5 mils to 5 mils thick. Have

  The laminate structure may be created by any known technique. For example, a prelaminate structure can be created by plying a preformed film of ionomer-PVOH composition with a substrate followed by a heated nip roll or oven to form the laminate.

  In these non-dispersion coating methods, after coating the substrate, the coated substrate is cooled to provide a solid ionomer-PVOH composition on the substrate. As used herein, “cooling” refers to the temperature at which an ionomer-PVOH coating is reduced under ambient conditions (temperatures of 20-30 ° C. and ambient pressure) and / or such as by the use of chill rolls. Including cooling by application.

  Additional layers may be applied to the coated substrate following coating. For example, additional aqueous or solvent-based dispersions that do not contain the ionomer-PVOH combination may be applied to the coated substrate. Alternatively, the multilayer structure may include additional thermoplastic material applied over the ionomer-PVOH layer by extrusion coating, lamination, and the like. In such cases, the ionomer-PVOH coating becomes the inner layer in the multilayer structure.

  The ionomer-PVOH coating composition can also be housed between two layers of a substrate in a sandwich-like manner. Some layer assemblies can also be assembled up and down. For example, this arrangement may include an ionomer-PVOH layer, a substrate layer, another ionomer-PVOH layer, another substrate layer, etc., depending on the desired use of the structure. Other arrangements may include variations of the sandwich arrangement described above, including multiple ionomer-PVOH layers, multiple substrate layers, etc. (including mixtures thereof).

  In such cases, in the aqueous dispersion coating process, the ionomer coating may be maintained in an aqueous state during assembly of the layered structure followed by drying. In the resulting layered structure, the ionomer-PVOH coating may function as an adhesive layer that bonds the substrate layers together.

  The coated substrates described herein may be used as film or sheet articles for various end uses. Alternatively, the originally prepared coated substrate may be further processed to give a more complete article.

  For example, the coated substrate may be part of a package that includes the coated substrate. The packaging may include a coated substrate film or sheet wrapped around the packaged product, and may include other packaging materials. The package may be formed from one or more portions of a coated substrate that are joined together, for example, by heat sealing. The ionomer-PVOH coating is easily heat sealable, allowing the manufacture of packages containing coated paper substrates that do not require additional adhesive for sealing. Such packaging or containers may be in the form of pouches, bags, boxes, cartons, cups, parcels and the like.

  A film or sheet comprising a coated substrate can be further processed by thermoforming the molded article. For example, a film or sheet comprising a coated substrate as described herein can be formed into a molded piece that can be included in packaging. Thermoformed articles typically have a shape in which a single material forms a recessed surface such as a tray, cup, can, bucket, tab, box or ball. The thermoformed article may also include a film or sheet having a cup-like recess formed therein. The thermoformed film or sheet may be shaped to match the shape of the material packaged therein. The flexible film retains some flexibility in the resulting molded article when thermoformed as described. The thicker the thermoformed sheet, the more semi-rigid or rigid articles can be given. The thermoformed article may be combined with additional elements, such as a planar film that generally functions as a lid that is sealed to the thermoformed article.

  Preferably, the container contains a snack food, such as potato fries, crackers, cookies, cereals or nuts; dried foods, soup mixes, coffee, French fries, sandwiches, pet foods, etc. Suitable for transportation or storage. Frozen or refrigerated foods such as ice cream, vegetables, waffles, etc. may also be packaged in a package containing a coated substrate. Non-food items such as detergents and soaps may also be packaged in a package that includes a coated substrate. Products for serving food, such as soft drink cups, plates, balls, etc., may also be prepared from the coated substrate.

  The pouch is formed from the coated web stock by cutting and heat sealing separate pieces of the coated web stock and / or by a combination of folding and heat sealing and cutting. The coated substrate may be formed into a pouch by overlaying and heat sealing the ends of the substrate to form a seal and then heat sealing (cross-sealing) over the length of the tube. Other packaging includes containers, capping films such as cups or tabs prepared from coated substrates as described herein, and coated substrates to improve properties such as stiffness and appearance A container, which may further comprise a flexible wrap made by laminating the to a separate web stock.

  Preferred packaging includes one or more preferred or noteworthy or structures as described herein. Preferred packaged products comprise one or more preferred or noteworthy compositions, films, structures or packaging as described herein.

  After preparation, the coated substrate can then take advantage of the immediate dispersibility of the ionomer-PVOH composition in water, for example, to allow for reusability.

  Once used for its intended purpose, such as packaging or food service, the coated substrate is readily recyclable by treatment with hot water. The ionomer-PVOH coating is easily dispersed in hot water, allowing it to be removed from the substrate. In the case of a preferred paper substrate, the paper is recyclable by conventional means used in the paper industry, within the limits on coat weight and ionomer content and paper weight.

  A recycling process may be considered to recover usable fibers from a substrate such as paper and may include a process in which a container and water are contacted at a temperature as low as ambient to about 80 ° C. . In some embodiments, the temperature is in the range of 80-90 ° C, or 80-85 ° C, or 85-90 ° C. However, even though water dispersible ionomer-PVOH compositions can be dispersed at such temperatures, it can be appreciated that they can be dispersed at temperatures in excess of 90 ° C. Also, in some embodiments, the container may be cut into pieces prior to contacting with water. The recovered fibers can be reused to prepare other articles, including new containers.

  Under normal circumstances, the water dispersible composition can be well dispersed in warm water in 1 hour or less, such as 30 minutes or less or 20 minutes or less. Once the aqueous dispersible ionomer composition is dispersed in water, the substrate material (ie, recyclable fibers) can be recovered by standard methods. For example, non-water dispersible materials contained in a container, such as a paperboard base material or aluminum foil, can be separated from the aqueous phase for recycling, for example, by filtration. Optionally, it may not be necessary to completely separate the dispersed ionomer-PVOH composition from the paper pulp. Recycled paper typically contains some and only a few dispersed “plastics”, waxes, hot melt components, etc., so that the fiber can be reused and, if the particle size is small, the minimum amount Is acceptable.

  Removal of the coating from the substrate material and / or recovery of the substrate material may include one of the following embodiments:

  The container disclosed herein (preferably after use) is first mixed with water under low shear conditions at room temperature (20-25 ° C.), then the temperature or mixture is 80-90 ° C. To be raised.

  The container disclosed herein (preferably after use) is mixed with water under low shear conditions at room temperature, and then the temperature of the mixture is raised to 85-90 ° C.

  The containers disclosed herein (preferably after use) are mixed under low shear conditions with water preheated to a temperature of 80-90 ° C.

  The containers disclosed herein (preferably after use) are mixed under low shear conditions with water preheated to a temperature of 85-90 ° C.

  Following treatment with hot water to remove the coating, the substrate material can be collected and recycled into a new article. For example, paper and paperboard materials can be repulped and processed into new articles by methods known in the art.

  The resulting aqueous ionomer-PVOH dispersion can also be further processed to recover the ionomer-PVOH composition. For example, excess water can be removed by distillation, evaporation, lyophilization, etc. to provide the composition in solid form. Alternatively, the ionomer can be purified from other water soluble materials by subjecting the aqueous dispersion to an acid treatment to give a base ethylene acid copolymer that is insoluble in water. The solid acid copolymer can be re-neutralized according to the methods disclosed herein to provide an ionomer.

  Table 1 summarizes the ethylene methacrylate dipolymers having copolymerized units of methacrylic acid at the indicated weight percent of the total acid copolymer used to prepare the ionomers of Table 2. Ionomers were prepared from these acid copolymers using standard conditions. Melt flow rate (MFR) was measured according to ASTM D1238 at 190 ° C. using a load of 2160 g. A similar test is ISO 1133.

Ionomers Table 2 shows ionomers derived from ethylene methacrylate dipolymers with the indicated percentage of carboxylic acid groups neutralized with sodium hydroxide to form sodium salts or with potassium carbonate to form potassium salts. To summarize. Water dispersibility is determined according to the following procedure, which illustrates the addition of non-neutralized acid copolymer or ionomer to heated water. The procedure produced a mixture of water and a 10 wt% solids load (weighed before addition to water). In a 1 quart (946.4 ml) metal can placed in a heating mantle element, 500 ml of distilled water was added. An overhead paddle stirrer (3-paddle propeller type stirrer) is positioned in the center of the metal can and turned on to give slow mixing. A thermocouple was positioned below the water surface between the paddle stirrer and the metal can surface. The paddle stirrer was usually set at a speed of about 170 rpm at the start of the process and was generally raised to about 300-470 rpm as the viscosity gradually increased during dispersion formation. The distilled water was then heated by an Omega temperature controller to a temperature of 90 ° C. The ionomer shown in Table 2 (55.5 grams, in the form of melt cut pellets) was then added in one portion and the resulting mixture was stirred for a total of 20 minutes. The resulting mixture was then allowed to cool to room temperature. For materials that formed dispersions at a given temperature (shown as “good” in Table 2), dispersions were generally formed in less than 10 minutes and were stable even after cooling to room temperature. As used herein, “stable” the dispersion (liquid without visible solids) did not show any visible change after initial cooling or upon storage at room temperature. Means that. The sample remained as a liquid without settling after storage at room temperature for a period of several weeks or longer.

  ION-2 and ION-7 surprisingly demonstrate a preferred embodiment of forming a dispersion at a relatively low temperature of 80 ° C., but based on the same parent ethylene acid copolymer with a higher degree of neutralization Equivalent compositions (ION-9 and ION-8, respectively) did not demonstrate the same advantage.

  Samples of poly (vinyl alcohol) (PVOH) compositions are commercially available from DuPont under the trade name Elvanol® and their degree of hydrolysis and 4 wt% aqueous viscosity at 20 ° C. are tabulated. Report to 3. PVOH-7 is a PVOH copolymer and is therefore not characterized in terms of% hydrolysis. However, it is considered fully hydrolyzed because there are very few remaining acetate groups. PVOH-8 and PVOH-9 are available from Chang Chung Petrochemical Co., Taiwan. (CCPC) commercially obtained. In Table 3, an aqueous solution of PVOH material was prepared by suspending the solid material in cold water and then heating to 90-95 ° C. with stirring until all solid material was invisible. The poly (vinyl alcohol) solution was a clear, clear solution.

Preparation Examples 1-12 and Comparative Examples C1-C4
These samples show how to mix a preformed aqueous PVOH solution with a preformed ionomer dispersion. 11.6 wt% of ION-2 was prepared by suspending the solid material in hot (90-95 ° C) water and stirring until all solid material was not visible. The ionomer dispersion was a translucent milky white liquid.

  Blends of the aqueous ionomer dispersion summarized in Table 3 and the aqueous PVOH solution were prepared by mixing them together at room temperature to prepare the blend composition summarized in Table 4. Specifically, each of the aqueous PVOH solutions was mixed with the aqueous ionomer dispersion in a ratio of 80:20; 60:40; 40:60 and 20:80 (weight: weight).

  The viscosities of the Examples and Comparative Examples were measured using a TA Instruments AR2000 stress-controlled rheometer equipped with a narrow gap (1 mm) concentric cylindrical structure. The concentric cylindrical structure consists of a temperature control jacket, a cup (or starter), and a DIN rotor (or bob). When testing, the sample was placed in the cup and then the rotor was inserted. For very low viscosity fluids such as ionomer dispersions, more cylindrical rotors and often higher rpm are used. Higher viscosity fluids such as PVOH solutions or ionomer-PVOH blend dispersions required a rotor with a thin shaft with a disc and were run at a relatively low rpm. Since the resistance of the fluid on the rotor is proportional to its surface area, the contribution to the measured torque from the rotor shaft was small relative to the thick part of the rotor. As a result, the fluid height on the shaft is not critical and the cup was filled so that the fluid height in the cup exceeded the thick portion of the rotor when the rotor was inserted. A solvent cover was placed on top of the cup. This helped to minimize the effect of solvent evaporation or moisture absorption on the measured properties.

The instrument bias was checked using a nominal 10 cP (actual viscosity 9.5 cP) and nominal 10,000 cP (actual viscosity 9860 cP) viscosity standard. The bias was less than 4% for both standards at a shear rate of 0.1 to 100 sec- ¹ .

The viscosity of each test sample was measured at 25 ° C. The concentric cylindrical structure was set at the desired test temperature. A total amount of each material for 20 mL is poured into the cup using a syringe, the solution is mixed using a spatula for 10 seconds, the DIN is lowered to the 5920 μm gap between the bottom of the rotor and the cup, and the cover Was placed on the structure and the test was started. A time sweep was performed at a shear rate of 20 sec- ¹ . The viscosity of each sample was monitored as a function of time by taking data points every 10 seconds up to 1800 seconds. A fresh sample is added each time, and the measurement is performed in at least two ways, and the average value is reported in Table 4 as a representative time point. The entry column “Viscosity Ratio” indicates the ratio between the viscosity of the ionomer-PVOH blend dispersion and the viscosity of the PVOH dispersion without ionomer, each measured in 1800 seconds.

  Table 5 summarizes a similar comparison using a 10 wt% aqueous solution of PVOH-4 blended with a 10 wt% aqueous dispersion of ION-2. Viscosity measurements for ION-2 were performed at 100 rpm and 20 ° C. using a cylindrical rotor, and PVOH-4 and its blends were performed at 60 rpm and 20 ° C. using a rotor consisting of a disc shaft.

  The viscosity behavior of the 60:40 blend of PVOH-4 and ION-2 was similar to the behavior of the other samples. Similar viscosity behavior was observed for PVOH-6, PVOH-7, PVOH-8 and blends of PVOH-9 and ION-2 in aqueous dispersions.

Coating Examples 1-24 and Comparative Examples C1-C7
These examples summarized in Tables 6 and 7 demonstrate coating paperboard with an aqueous dispersion. Aqueous ionomer-PVOH dispersions were prepared according to the general procedure described above. The substrate is a 0.22-inch caliper, nominally 77 lb basis weight, coated on one side with clay for printability, commercially available as CartonMate® Bleached Board from RockTenn Converting Company, Demopolis AL Met. An 8 inch x 11 inch sample of the substrate was coated on the opposite side of the clay coating in the following manner. The sample was weighed and then attached to a flat piece of plywood with a spring-loaded clip at one end. Approximately 80 ml of the ionomer-PVOH dispersion, prepared as described above, is applied to the clipped ends, spread with a single motion with a 0.0036 inch wire wound Meyer rod, flattened and the paper sample remaining The part was covered. Excess dispersion was removed by a spreading operation. Due to the difficulty of drying to constant weight, the dry coating weight pick-up is estimated by immediately reweighing the sample to determine the wet coating weight and calculating the amount of polymer present from the weight percent of the dispersion. did. Depending on the diameter of the wire wound around the rod, the coating weight can be from about 4 grams to about 12 grams per square meter. In these examples, the coating weight was about 6 grams to about 12 grams per square meter.

  The wet coated sample was dried at 105 ° C. for 5 minutes in a forced air oven set. After drying, the samples were allowed to cool at room temperature and then further adjusted as required for further testing. The ionomer-PVOH coating appeared colorless, uniform and slightly shiny than the uncoated control.

  The coated samples were tested for grease resistance with the Kit test (TAPPI T559). The Kit test is a series of mixed solvents (castor oil, n, numbered from 1 (100% castor oil) to 12 (toluene / n-heptane ratio 45/55) in order of decreasing viscosity and surface tension. -Combination of heptane and toluene). The reported number is the highest numbered solvent that shows no signs of contaminating the test material after 15 seconds of contact.

  The coated samples were tested for water resistance by the Cobb test (TAPPI T441). This test measures weight gain due to water absorption under standard conditions. Cobb test time can vary depending on the type of paper. The test used herein was performed by pouring 100 ml of water onto a paper sample clamped under a ring surrounding 100 square centimeters and discarding the water after 2 minutes exposure. Multiply the gain by 100 and report the result in grams / square meter.

  The results for both the Kit and Cobb tests are summarized in Table 8 and reported as the average of the two samples. The uncoated substrate showed very poor results for grease resistance in the Kit test and relatively high water absorption in the Cobb test. The substrate coated with an aqueous dispersion of ION-2 alone (Comparative Example C1) showed an improvement over the uncoated substrate in both the Kit and Cobb tests. Substrates coated with PVOH-6 alone (Comparative Examples C3 and C4) showed better results than those coated with ionomer in the Kit test, but absorbed more water. Examples 1 to 8 coated with an aqueous dispersion of ionomer and PVOH-6 showed excellent grease resistance and water absorption compared to uncoated substrates, as indicated by high scores in the Kit test. Gave a decrease. The Kit test results are surprisingly superior to those expected from the weighted average of substrates coated with ionomer or PVOH-6 alone. Results for samples coated with blends of ION-2 with PVOH-7, PVOH-8 and PVOH-9 were similar. In general, excellent grease resistance can be obtained at a PVOH: ionomer ratio of about 10:90 to about 40:60 while providing the best water absorption resistance.

  The results summarized in Table 8 show that an aqueous blend of ionomer and PVOH can be used as a coating that provides excellent grease resistance and improved water resistance to paper and paperboard substrates. The addition of a relatively small amount of PVOH to the ionomer dispersion dramatically improves the grease resistance. The best results are given by an aqueous dispersion of ION-2 and PVOH-9, which has a degree of hydrolysis of 95-97% and a 4% by weight aqueous viscosity at 20 ° C. of 25-30 cP.

Claims (16)

(A) (i) 80-94 mol% hydrolysis and 15 centipoise (cp) 4 wt% aqueous viscosity at 20 ° C .; or (ii) 95 mol% -100 mol% hydrolysis. 99 to 1% by weight of a poly (vinyl alcohol) composition, based on the combination of (a) and (b), and (b) copolymerized units of ethylene, and a parent Based on the total weight of the acid copolymer, comprising a parent acid copolymer comprising 18-30% by weight copolymer units of acrylic acid or methacrylic acid, said acid copolymer measured at 190 ° C. using a load of 2160 g according to ASTM D1238 Calculated for a non-neutralized parent acid copolymer having a melt flow rate (MFR) of 200-1000 g / 10 min. Based on the acid content, 50-70% of the carboxylic acid groups of the copolymer are neutralized to carboxylates containing potassium cations, sodium cations, or combinations thereof, (a) and (b) A blend composition comprising from 1 to 99% by weight of an ionomer composition, based on the combination of:   (B) is present in the combination of (a) and (b) in an amount of 10 to 95% by weight, preferably (b) is in an amount of 60 to 95% by weight of (a) and (b) The blend composition of claim 1, wherein the blend composition is present in a combination with and (a) is present in a complementary amount.   3. Blend composition according to claim 1 or 2, characterized in that the poly (vinyl alcohol) has a degree of hydrolysis of 80-93 mol and a 4 wt% aqueous viscosity at 20 [deg.] C of 7 cp or less.   Blend composition according to claim 1 or 2, characterized in that the poly (vinyl alcohol) has a degree of hydrolysis of 95-100 mol%.   The blend composition according to any one of claims 1 to 4, wherein the acid copolymer has an MFR of 250 to 400 g / 10 min.   6. A composition according to any one of the preceding claims in the form of an aqueous dispersion comprising water and 0.001 to 50% by weight of a combination of (a) and (b).   An article comprising the blend composition according to any one of claims 1-5.   A coated substrate comprising a surface layer on a substrate, wherein the surface layer comprises a blend composition according to any one of claims 1-5, preferably the substrate is paper, paperboard, Cardboard, pulp molded shapes, textiles, materials made from synthetic fiber spun fabrics, films, open cell foams, closed cell foams, or metal foils, more preferably paper, paperboard, cardboard, or pulp molded shapes, The article of claim 7 comprising a multilayer structure. Characterized by (1) water, and (i) a degree of hydrolysis of 80-94 mol% and a 4 wt% aqueous viscosity at 20 ° C. of 15 cp or less; or (ii) a degree of hydrolysis of 95 mol% -100 mol% Providing an aqueous poly (vinyl alcohol) solution comprising a poly (vinyl alcohol) composition comprising poly (vinyl alcohol);
(2) comprising a parent acid copolymer comprising 18-30 wt% copolymerized units of acrylic acid or methacrylic acid, based on the total weight of the copolymerized units of ethylene and the parent acid copolymer, said acid copolymer comprising 2160 g The total carboxylic acid content of the parent acid copolymer as measured for non-neutralized parent acid copolymer, having a melt flow rate (MFR) of 200-1000 g / 10 min, measured according to ASTM D1238 at 190 ° C. using a load. Providing an ionomer composition wherein, based on amount, 50-70% of the carboxylic acid groups of the copolymer comprise an ionomer neutralized to a carboxylate comprising a potassium cation, a sodium cation, or a combination thereof. When;
(3) mixing the ionomer composition with the aqueous poly (vinyl alcohol) composition solution, optionally with heating, to give a heated aqueous blend dispersion;
(4) The heated aqueous blend dispersion may be cooled to a temperature of 20-30 ° C., wherein the combination comprises the step of remaining dispersed in the liquid phase. A method of producing an aqueous dispersion.   The aqueous poly (vinyl alcohol) solution comprises 0.001 to 50% by weight of the poly (vinyl alcohol) based on the total weight of the poly (vinyl alcohol) and water, preferably the poly (vinyl alcohol) ) Is characterized by a hydrolysis degree of 80 to 93 mol% and a 4 wt% aqueous viscosity at 20 ° C. of 7 cp or less.   The ionomer composition is an aqueous dispersion comprising the ionomer and water, the aqueous dispersion contacting the solid ionomer composition with water at a temperature of 80-100 ° C; optionally followed by 20-30 Produced by cooling to a temperature of 0 ° C., the ionomer remains dispersed in the aqueous phase; the aqueous dispersion comprises 0.001 to 50% by weight of the ionomer, based on the total weight of the ionomer and water. 11. A method according to claim 9 or 10, comprising an ionomer. The ionomer composition is in solid form and the mixing step comprises:
(1) (a) heating the aqueous poly (vinyl alcohol) solution to a temperature of 80 to 100 ° C;
(B) contacting the solid ionomer composition with the heated aqueous poly (vinyl alcohol) solution;
(C) continuing heating at a temperature of 80-100 ° C. until the solid ionomer composition is completely invisible; or (2) (d) (d) the solid ionomer composition is converted into the aqueous poly (vinyl alcohol). Contacting the solution to give a mixture; and (e) heating the mixture to a temperature of 80-100 ° C. until the solid ionomer composition is completely invisible;
The method according to claim 9 or 10, comprising: A method of forming a coating comprising a blend of ionomer and poly (vinyl alcohol) on a substrate, comprising:
(1) A step of preparing the blend composition according to any one of claims 1 to 5;
(2) a step of preparing a substrate;
(3) coating the blend composition onto the substrate.   The substrate is made of paper, paperboard, cardboard, pulp molded shape, textile, synthetic fiber spun fabric, film, open cell foam, closed cell foam, or metal foil, preferably paper, paperboard, cardboard 14. The method of claim 13, comprising a pulp molded shape.   13. The blend composition is provided in the form of an aqueous dispersion comprising water and 0.001 to 50% by weight of a combination of (a) and (b), preferably according to any one of claims 9-12. The blend composition is coated on the substrate as the aqueous dispersion; the method comprises (4) drying the coated substrate at a temperature of 20 to 150 ° C. The method according to claim 13 or 14, further comprising:   The blend composition is provided in the form of a preformed film comprising a combination of (a) and (b), and (3) comprises (3a) an ionomer-polyolefin film layer adjacent to the substrate. And (3b) laminating the ionomer-polyolefin film layer to the substrate at a temperature of 50 to 150 ° C., optionally with an applied pressure; The method according to claim 13 or 14, further comprising the step of cooling the coated substrate to a temperature of 20-30C.