MXPA06010544A - Polymer sheets and methods of controlling adhesion of polymer sheets to glass - Google Patents

Abstract

The present invention is in the field of polymer sheets comprising poly(vinyl butyral) and sodium acetate and methods of producing and using the same, and more specifically, the present invention is in the field of polymer sheets comprising plasticized poly(vinyl butyral), sodium acetate, and an adhesion control agent.

Description

POLYMER PLATES AND METHODS TO CONTROL THE ADHESION OF THE POLYMER PLATES TO THE GLASS TECHNICAL FIELD OF THE INVENTION The present invention is within the field of polymer sheets comprising poly (vinyl butyral) and sodium acetate, as well as the methods for producing and using them and, more specifically, the present invention is within the scope of polymer sheets comprising poii (vinylic butyral), sodium acetate, as well as an adhesion control agent.

BACKGROUND OF THE INVENTION Poly (vinyl butyral) (PVB) is commonly used in the manufacture of polymer sheets that can be used as an intermediate layer in light transmitting laminates such as safety glass or polymeric laminates. Security glass generally refers to a transparent laminate comprising a poly (vinyl butyral) sheet disposed between two sheets of glass. Safety glass is frequently used to provide a transparent barrier in architectural and automotive openings. Its main function is to absorb energy, such as that caused by blowing from an object, without allowing penetration through the opening. The additives for the formulation of the sheet generally include at least one adhesion control agent (hereinafter "ACA") to modify the adhesion of the sheet to the glass, so that an adequate level of adhesion can be maintained for prevent glass from splintering, while continuing to provide adequate absorption of energy if an impact occurs. The safety glass can be formed by a process in which two layers of glass and an intermediate layer of plastic, such as poly (vinyl butyral), are assembled to form a pre-press, welded to form a pre-laminate and finished as an optically transparent laminate. The assembly phase may involve sitting a piece of glass, coating the glass with a sheet of poly (vinyl butyral), laying a second piece of glass on the poly (vinyl butyral) sheet and then trimming the excess poly (vinyl butyral) ) on the edges of the glass layers. The intermediate plastic layer can be produced by mixing poly (vinyl butyral) polymer with one or more plasticizers and, optionally, with one or more other ingredients, as well as by melt processing the mixture to form sheets, which typically are gathered and rolled up to its storage and transportation. The process of making poly (vinyl butyral) resin may involve the use of acids to catalyze the formation of vinyl acetal from aldehyde precursors and vinyl alcohol. After the formation of the acetal, the acids can be neutralized using an appropriate base. This procedure will generally leave residual acetate trapped within the poly (vinyl butyral) resin, which can have an impact on both the stabilization and adhesion quality. However, the residual concentration of the acetate can be a limiting factor when certain adhesion and other characteristics are desired in the finished poly (vinyl butyral). Accordingly, additional improved compositions and methods are required to improve the characteristics of the polymer and poly (vinyl butyral) sheets and, specifically, the poly (vinyl butyral) sheets, without adversely affecting the polymer sheet resulting.

BRIEF DESCRIPTION OF THE INVENTION Now, in accordance with the present invention, polymer sheets comprising poly (vinyl butyral) and sodium acetate have been developed and, more specifically, polymer sheets comprising poly (vinyl butyral) containing sodium acetate have been developed. and an adhesion control agent. The present invention includes a polymer sheet, which comprises: plasticized poly (vinyl butyral), sodium acetate, and a magnesium salt, wherein the dosage of said magnesium salt is at least 4 mg., wherein the dosage of alkalinity attributable to said sodium acetate is at least 20 and wherein the proportion of said dosage of said magnesium salt with respect to the total alkalinity dosage is at least 0.2. The present invention includes a polymer sheet, comprising: plasticized poly (vinyl butyral), sodium acetate, potassium acetate and a magnesium salt, wherein the dosage of said magnesium salt is at least 9.0, wherein the total alkalinity dosage is at least 20, wherein the proportion of said dosage of said magnesium salt with respect to said total alkalinity dosage is at least 0.2 and wherein the proportion of parts per million of potassium with Regarding parts per million of sodium is less than 1.0. The present invention includes a method for manufacturing a polymer sheet, comprising: forming a poly (vinyl butyral) resin, wherein said resin comprises sodium acetate and a magnesium salt.; adding a plasticizer to said resin to form a cast; and forming said polymer sheet with said casting, wherein the dosage of said magnesium salt is at least 4, wherein the dosage of alkalinity attributable to said sodium acetate is at least 20 and wherein the proportion of said dosage of said magnesium salt with respect to the total alkalinity dosage is at least 0.2. The present invention includes a laminated glass panel, comprising: a glass panel and a polymer sheet, wherein said polymer sheet comprises: plasticized poly (vinyl butyral), sodium acetate and a magnesium salt, in wherein the dosage of said magnesium salt is at least 4, wherein the dosage of alkalinity attributable to said sodium acetate is at least 20 and wherein the proportion of said dosage of said magnesium salt with respect to the dosage of total alkalinity is at least 0.2.

DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention, it has been found that sodium acetate, which functions as both a stabilizer and an adhesion control agent, is a weaker adhesion control agent than potassium acetate. This surprising result allows a proportionally greater amount of sodium acetate to be used in the polymer sheets relative to potassium acetate. In various embodiments of the present invention, relatively high dosages of sodium acetate are used to produce products having improved yellowness indexes and improved resistance to delamination of the edges under certain conditions, without adversely affecting the value of adhesion of the finished product. Additionally, higher amounts of sodium acetate can be used to replace, totally or to a significant extent, the conventional component of potassium acetate of many intermediate layers of laminated glass. These results are especially desirable in the intermediate polymer layers which also contain magnesium salt adhesion control agents since, conventionally, the amount of potassium acetate that could be used to produce a product with a given set of specifications, depended in part of the amount of magnesium salt used. As described throughout, the present invention provides embodiments in which sodium acetate is used to eliminate or reduce the amount of potassium acetate at the same time that it does not simultaneously require a reduction of magnesium salt and , in some modalities, allowing an increase in the magnesium salt. Poly (vinyl butyral), as well as other vinyl acetals, can be manufactured by various methods, as is known in the art. Two methods that have been employed are the solvent process and the aqueous process (see, for example, Vinyl Acetal Polymers, in Encyclopedia of Polymer Science &Technology, 3rd edition, volume 8, pages 381-399, by BE Wade (2003). )). In either method, the poly (vinyl alcohol) is reacted with an aldehyde in the presence of mineral or organic acid catalysts to produce a poly (vinyl acetal) and water. If butyraldehyde is used as the aldehyde, then the resulting acetal is poly (vinyl butyral). Any suitable acid can be used and will generally include a catalyst of primary acid and acetic acid. In various embodiments of the methods of the present invention, sulfuric acid is used as a primary acid catalyst.

After formation of the acetal in any of the above methods, the neutralization of the residual acids can be achieved, for example, by the addition of a hydroxide compound. As described in U.S. Patents 5,728,472 and 3,271, 235, for example, either sodium hydroxide or potassium hydroxide can be used to neutralize the acids. The use of any of these hydroxides can result in a residual dosage of the acetate salts within the polymer matrix (see, for example, US Patent 2,496,480). This residual dosage is generally desirable because it prevents degradation of the finished polymer due to the harmful action of residual sulfur oxides (if sulfuric acid is used as the primary acid catalyst, for example). The use of potassium hydroxide as a neutralizing agent has the additional impact on the finished poly (vinyl butyral) of affecting the adhesiveness of the polymer, for example, to glass. This adhesiveness of the finished polymer sheet can be further modified by the inclusion of optionally false multivalent, aromatic metal substitution compounds, such as magnesium salts. The present invention relates to the unexpected result that high levels of sodium acetate, with respect to an equivalent amount in moles of potassium acetate, produce a polymer sheet that is more adhesive in the glass under different conditions. Therefore, the present invention includes polymeric sheets having a relatively high sodium acetate dosage, as well as methods for manufacturing those polymeric sheets and methods for controlling the adhesiveness in those polymeric sheets by increasing the amount of sodium acetate in the finished product . In various embodiments, the present invention includes a polymer sheet, comprising: plasticized poly (vinyl butyral) and sodium acetate in a dosage sufficient to impart the desired adhesiveness to the polymer sheet. In different embodiments, the dosage of alkalinity attributable to the sodium acetate in the polymer sheet is at least 25, of at least 30, of at least 35, of at least 37, of at least 40, of at least 43, of at least 46 or at least 50. In different modalities, sodium is present in the finished polymer sheet at least 100 ppm, at least 120 ppm, at least 140 ppm , at least 150 ppm or at least 160 ppm in a resin based on poly (vinyl butyral). In these modalities, potassium and potassium acetate can be produced as insubstantial components. In other embodiments of the present invention, both sodium acetate and a magnesium salt are used as ACAs in a polymer sheet. In these embodiments, reducing the adhesion control of sodium acetate optionally allows the use of a relatively greater amount of sodium acetate and / or a magnesium salt, to achieve the desired adhesiveness of the final product. This result is particularly desirable in applications such as windshields, where conventional concentrations of potassium acetate and magnesium salt in the final product can lead to edge delaminating under conditions of high temperature and high humidity. The foil formulations can be optimized with higher concentrations of magnesium salt, to achieve better edge stability for medium to high adhesion and a higher total alkaline dosage level. Specifically, in embodiments comprising both sodium acetate and a magnesium salt, the ratio of the dosage of the magnesium salt to the total alkaline dosage can be at least 0.2, at least 0.3, at least 0 4, at least 0.5, at least 0.75, at least 1.0 or at least 1.2, wherein the dosage of the magnesium salt (determined as defined below) may be at least 4, so minus 8, at least 12, at least 16, at least 20 or at least 24 and wherein the alkaline dosage attributable to sodium acetate (determined as defined below) may be at least 20, at least 30, at least 40, at least 50, at least 60, at least 70 or at least 80. These modalities may not have potassium acetate or be basically free of potassium acetate (less than 5 alkaline dosage attributable to potassium acetate). As used herein, "alkaline dosage attributable to sodium acetate" means the portion of the total alkaline dosage that results from the acid neutralization effect of sodium acetate. Similarly, "alkaline dosage attributable to potassium acetate" refers to the portion of the total alkaline dosage that is the result of the acid neutralization effect of potassium acetate. The determination of these proportions is described below. In other embodiments of the present invention, in addition to sodium acetate and a magnesium salt, the polymer sheets may comprise a non-insubstantial amount of potassium acetate. In these embodiments, both potassium acetate and sodium acetate function as adhesion control agents and stabilizers and the proportion of the magnesium salt dosage with respect to the total alkaline dosage, it can be at least 0.2, at least 0.3, at least 0.4, at least 0.5, at least 0.75, at least 1.0 or at least 1.2, where the dosage of the magnesium salt (determined as defined below) can be at least 4, at least 8, at least 12, at least 16, at least 20 or at least 24 and where the total alkaline dosage (determined as defined below) may be at least 20, at least 30, at least 40, at least 50, at least 60, at least 70 or at least 80 and wherein the proportion of potassium with respect to Sodium, measured in parts per million (ppm), can be less than 1.0, less than 0.8, less than 0.6, less than 0.4, or less than 0.2. Magnesium salts that can be used with these embodiments of the present invention include, but are not limited to, those described in U.S. Patent 5,728,472, such as magnesium salicylate, magnesium nicotinate, magnesium di- (27-aminobenzoate), Magnesium (3-hydroxy-2-naphthoate), and magnesium bis (2-ethyl butyrate). The ppm, dosage and proportions given elsewhere herein for the magnesium salt can be applied specifically to each of the magnesium salts listed above and, in particular, to the magnesium bis (2-ethyl butyrate) (number of chemical abstracts 79992-76-0). In various embodiments of the present invention, the magnesium salt is magnesium bis (2-ethyl butyrate). As used herein, "polymer sheet" means any polymeric composition formed by any suitable method to produce a thin layer that is suitable for use as an intermediate layer in laminated glass structures. In various embodiments, the present invention includes a method for manufacturing a polymer sheet, comprising: forming a poly (vinyl butyral) resin, wherein said resin comprises any of the combinations of sodium acetate, magnesium salt and, optionally, , potassium acetate, adding a plasticizer to the resin to form a cast, as well as forming the polymer sheet with the cast, wherein the polymer sheet has any of the combinations of the components provided throughout the present. In a specific embodiment, the method comprises forming a poly (vinyl butyral) resin, wherein said resin comprises sodium acetate and a magnesium salt, adding a plasticizer to said resin to form a cast and forming said polymer sheet with said casting, wherein the dosage of said magnesium salt is at least 4, wherein the dosage of alkalinity attributable to said sodium acetate is at least 20 and wherein the proportion of said dosage of said magnesium salt with regarding the total alkalinity dosage is at least 0.2. As used herein, "resin" refers to the polymer component (eg, poly (vinyl butyral)) that is removed from the mixture resulting from acid catalysis and subsequent neutralization of the polymer precursors. The resin will generally have other components besides the polymer, for example poly (vinyl butyral), such as acetates, salts and alcohols. As used herein, "casting" refers to a molten mixture of resin with a plasticizer and, optionally, other additives. In addition to the specific embodiment provided above, the above method can also be used to produce any of the polymer sheets provided anywhere herein that comprise both a magnesium salt such as sodium acetate and, optionally, potassium acetate, in the scales for those components provided anywhere in the present. Additionally, other components, as known in the art and described elsewhere herein, may be added to the polymer sheet during processing, to achieve the desired final product. In any of the methods of the present invention provided herein, sodium acetate and / or potassium acetate can be added to the polymeric resin after the neutralization of the acids.

This technique can be used, for example, when it is desired to raise the dosage or concentration of sodium acetate beyond the level produced by the neutralization process. For any of the polymer sheets of the present invention, potassium hydroxide may be used in addition to sodium hydroxide for the neutralization process and potassium acetate and / or sodium acetate may be added separately after the neutralization procedure, if so you want The polymer sheets made by the methods herein are part of the present invention and are included within the scope of the invention. The polymer sheets of the present invention can comprise any suitable polymer and, in a preferred embodiment, as exemplified above, the polymer sheet comprises poly (vinyl butyral). In any of the embodiments of the present invention provided herein comprising poly (vinyl butyral) as the polymer component of the polymer sheet, another embodiment is included in which the polymer component consists of or consists basically of poly (vin) L butiral). In these embodiments, any of the variations in the additives described herein can be used with the polymer sheet having a polymer consisting of or consisting basically of poly (vinyl butyral). In one embodiment, the polymer sheet comprises a polymer based on partially acetalized poly (vinyl alcohols). In another embodiment, the polymer sheet comprises a polymer selected from the group consisting of poly (vinyl butyral), polyurethane, poly (vinyl chloride), poly (ethylene-co-vinyl acetate), poly (ethylene terephthalate), combinations of same, as mixtures and composite structures and other similar ones. In one embodiment, the polymer sheet comprises poly (vinyl butyral). In other embodiments, the polymer sheet comprises plasticized poly (vinyl butyral). In additional embodiments, the polymer sheet comprises poly (vinyl butyral) and one or more other polymers. Other polymers having a suitable glass transition temperature can also be used. In any of the sections herein in which scales, values and / or preferred methods are specifically provided for poly (vinyl butyral) (for example, and without limitation, for plasticizers, component percentages, thicknesses and enhancing additives) of features), those scales also apply, when applicable, to the other polymers, polymeric compounds and polymer blends described herein as useful as the components in the polymer sheets. For embodiments comprising poly (vinyl butyral), the poly (vinyl butyral) can be produced by known acetalization methods involving reacting the poly (vinyl alcohol) with butyraldehyde in the presence of an acid catalyst, followed by neutralization of the catalyst , separation, stabilization and drying of the resin.

In various embodiments, the polymer sheet comprising poly (vinyl butyral), comprises from 10 to 35 weight percent (% by weight) of hydroxyl groups calculated as PVOH, from 13 to 30% by weight of hydroxyl groups calculated as PVOH or from 15 to 22% by weight of hydroxyl groups calculated as PVOH. The polymer sheet may also comprise less than 15% by weight of residual ester groups, 13% by weight, 11% by weight, 9% by weight, 7% by weight, 5% by weight or less than 3% by weight of residual ester groups calculated as polyvinyl acetate, with the balance being an acetal, preferably a butyraldehyde acetal but, optionally, including other acetal groups in a minor amount, eg a 2-ethyl hexanal group (see, for example, US Patent 5,137,954) or acetaldehyde. In various embodiments, the polymer sheet comprises poly (vinyl butyral) having a molecular weight greater than 30,000, 40,000, 50,000, 55,000, 60,000, 65,000, 70,000, 120,000, 250,000, or greater than 350,000 grams per mole. (g / mole or Daltons). Small amounts of a dialdehyde or trialdehyde may also be added during the acetalization step, to increase the molecular weight to more than 350 g / m (see, for example, US Patent Nos. 4,902,464.; 4,874,814; 4,814,529; 4,654,179) As used herein, the term "molecular weight" means the average molecular weight. Any suitable method can be used to produce the polymer sheets of the present invention. Details of suitable procedures for making poly (vinyl butyral) are known to the person skilled in the art (see, for example, U.S. Patents 2,282,057 and 2,282,026). In one embodiment, the solvent method described in Vinyl Acetal Polymers, in Encyclopedia of Polymer Science & Technology, 3rd edition, volume 8, pages 381-399, by B. E. Wade (2003). In another embodiment, the aqueous method described in that site can be used. Poly (vinyl butyral) is available commercially in various forms from, for example, Solutia Inc., St. Louis, Mo., as the Butvar ™ resin. Additives can be incorporated into the polymer sheet to improve its performance in a final product. Such additives include, but are not limited to, plasticizers, dyes, pigments, stabilizers (e.g., ultraviolet stabilizers), antioxidants, flame retardants, IR absorbers, combinations of the above additives and the like, as is known in the art. In various embodiments of the polymer sheets of the present invention, the polymer sheets may comprise from 20 to 60, from 25 to 60, from 20 to 80, or from 10 to 70 parts of plasticizer per one hundred parts of resin ( phr, for its acronym in English). Of course, other quantities may also be used as appropriate for the particular application. In some embodiments, the plasticizer has a hydrocarbon segment of less than 20, less than 15, less than 12, or less than 10 carbon atoms.

The amount of plasticizer can be adjusted to affect the glass transition temperature (Tg) of the poly (vinyl butyral) sheet. In general, larger amounts of plasticizer are added to reduce the Tg. The poly (vinyl butyral) polymer sheets of the present invention can have a Tg of 40 ° C or less, 35 ° C or less, 30 ° C or less, 25 ° C or less, 20 ° C or less and ° C or less. Any suitable plasticizer can be added to the polymeric resins of the present invention, in order to form the polymer sheets. The plasticizers used in the polymer sheets of the present invention may include esters of a polybasic acid or a polyhydric alcohol, among others. Suitable plasticizers include, for example, triethylene glycol di- (2-ethtyrate), triethylene glycol di- (2-ethylhexanoate), triethylene glycol diheptanoate, tetraethylene glycol diheptanoate, dihexyl adipate, dioctyl adipate, hexyl cyclohexyldipate, mixtures of heptyl and nonyl adipates, diisononil adipate, heptylnonyl adipate, dibutyl sebacate, polymeric plasticizers such as sebacic alkyds with oil modification and mixtures of phosphates and adipates such as those described in US Patent No. 3,841, 890 and adipates such as those described in US Patent No. 4,144,217 , as well as mixtures and combinations of the above. Other plasticizers that can be used are mixed adipates made from C4 to C9 alkyl alcohols and C4 to C10 cycloalcohols, as described in U.S. Patent No. 5,013,779, as well as C6 to C8 adipate esters, such as hexyl adipate.

The plasticizer additives and poly (vinyl butyral) polymer can be thermally processed and configured to form a sheet form in accordance with methods known to the person skilled in the art. An example of a method for forming a poly (vinyl butyral) sheet comprises extruding molten poly (vinyl butyral) comprising resin, plasticizer and additives (hereinafter "cast") by forcing the cast to pass through a sheet die. (for example, a die that has an opening that is substantially larger in one dimension than in a perpendicular dimension). Another example of a method for forming a poly (vinyl butyral) sheet comprises melting a cast with a die to a roll, solidifying the resin and subsequently removing the solidified resin in the form of a sheet. In either embodiment, the surface texture on either or both sides of the sheet can be controlled by adjusting the surfaces of the die opening or by providing a texture on the roll surface. Other techniques for controlling the texture of the sheets include variable parameters of the materials (for example, the water content of the resin and / or the plasticizer, the temperature of the melt, the molecular weight distribution of the poly (vinyl butyral) or combinations of the above parameters). Additionally, the sheet can be configured to include separate projections defining a temporary surface irregularity to facilitate removal of air from the sheet during the rolling processes, after which the high pressures and temperatures of the rolling process cause the projections they melt to form the sheet, thus producing a smooth finish. In different embodiments, the polymer sheets can have thicknesses of 0.1 to 2.5 millimeters, 0.2 to 2.0 millimeters, 0.25 to 1.75 millimeters and 0. 3 to 1.5 millimeters (mm). The present invention also includes stacks or rolls of any polymer composition sheet of the present invention described herein in any combination. The present invention also includes methods for manufacturing windshields and other laminated glass products, comprising the steps of arranging a polymer sheet of the present invention between two glass layers and laminating the three layer stack. Additionally, the present invention includes a laminated safety glass comprising a glass layer, which generally comprises silicon dioxide, disposed in contact with any of the polymer sheets of the present invention. A laminated safety glass comprising at least two glass sheets with an intermediate layer of polymer sheet disposed therebetween is included, wherein the polymer sheet is any of the polymer sheets described herein as embodiments of the present invention. The present invention also includes windshields, windows and other finished glass products comprising a polymer sheet of the present invention.

Now, various characteristics and techniques of measuring polymer sheet and / or laminated glass for use with the present invention will be described. The clarity of a polymer sheet and, in particular, a poly (vinyl butyral) sheet can be determined by measuring the transparency value, which is a quantification of the light not transmitted through the sheet. The transparency percentage can be measured according to the following technique. An apparatus for measuring the transparency quality, a Transparency Meter, Model D25, which is available from Hunter Associates (Reston, VA), may be used in accordance with ASTM D1003-61 (Reapproved1977) -Procedure A, using Illuminant C, at an observer angle of 2 degrees. In different embodiments of the present invention, the transparency percentage is less than 5%, less than 3% and less than 1%. The adhesion can be measured in accordance with the following technique and, since "adhesion" is used herein to refer to the quantification of the adhesion of a polymer sheet to the glass, the following technique is used to determine adhesion. Two-layered glass laminate samples are prepared with standard autoclave lamination conditions. The laminates are cooled to approximately -17 ° C and are manually bonded with a hammer to break the glass. All broken glass that does not adhere to the poly (viniI butyral) sheet is then removed and the amount of glass that remains adhered to the poly (vinyl butyral) sheet is visually compared to a set of standards. The standards correspond to a scale in which varying degrees of glass remain adhered to the poly (vinyl butyral) sheet. In particular, with a standard of zero adhesion, no glass remains adhering to the poly (vinyl butyral) sheet. With an adhesion standard of 10, 100% of the glass remains adhered to the poly (vinyl butyral) sheet. For the laminated glass panels of the present invention, different embodiments have an adhesion of at least 3, at least 5, at least 8, at least 9 or 10. Other embodiments have an adhesion of between 8 and 10, including these. The "yellow index" of a polymer sheet can be measured according to the following: transparent molded discs of polymer sheet with a thickness of 1 centimeter are formed, which have smooth polymeric surfaces which are basically flat and parallel. The index is measured in accordance with ASTM D 1925, "Standard Test Method for Yellowness Index of Plastics" from the transmittance of spectrophotometric light in the visible spectrum. The values are corrected to a thickness of 1 centimeter using the thickness of the specimen measured. As used herein, the "dosage" can be determined for the sodium acetate and potassium acetate (as used herein, the "total alkaline dosage") and the magnesium salts in a sheet sample using the following method. In order to determine the amount of resin in each sheet sample that is weighed, the following equation is used, where PHR is defined as pounds per hundred pounds of resin including plasticizer and any other additive for the resin in the preparation of original sheet sample. Grams of resin in sheet sample = Film sample grams (100 + PHR) / 100 Approximately 5 grams of resin in the sheet sample are the target mass used to estimate the amount of sheet sample to begin with the mass of resin calculated on the sheet sample used for each dosage determination. All degrees must be done the same day. The sheet sample is dissolved in 250 ml of methanol in a beaker. It can take up to 8 hours for the film sample to dissolve completely. A control only with methanol is also prepared in a beaker. Each of the sample and control are titrated with 0.00500 normal HCl using an automated pH titrator programmed to stop at a pH of 2.5. The amount of HCl added to each of the sample and the control to obtain a pH of 4.2, it is recorded. The dosage of HCl is determined in accordance with the following: Dosage HCl [mis 0.01 NHCI / 1 OOg resin] = 50 x (my sample HCl - my control HCl) Calculated grams of resin To determine the dosage of the magnesium salt, It uses the following procedure: 12 to15 ml of buffer solution with a pH of? .00, prepared from 54 grams of ammonium chloride and 350 ml of ammonium hydroxide diluted to one liter with methanol, as well as 12 to 15 ml. of black Ericrome T indicator are added to the control and each of the sheet samples, all of which have already been titrated with HCl, as described above. The titrant is then changed to an EDTA 0.000298g / ml solution prepared from 0.3263 grams of tetrasodium ethylenediaminetetracetate dehydrate, 5 milliliters of water, diluted to one liter with methanol. The EDTA titration is measured by the light transmittance at 596nm. The% transmittance is first adjusted to 100% in the sample or control before the titration is started while the solution has a bright magenta-pink color. When the transmittance at 596nm becomes constant, the EDTA titration is complete and the solution will have a deep indigo color. The volume of EDTA titrated to achieve the indigo blue titration variable is recorded for the control and each of the sheet samples. The dosage of magnesium salt is determined in accordance with the following: Magnesium salt dosage [as 1x10"7 moles of magnesium salt per gram of resin] = 0.000298g / ml EDTA x (more than EDTA sample - more than EDTA control) ) (grams of resin in sheet sample) x 380.2g / mole EDTA x 0.0000001 From this result, the total alkaline dosage, such as 1x10"7 moles of acetate salt per gram of resin, can be calculated in accordance with the following : Total alkaline dosing = Dosing of sheet HCl - (2 x Total dosage of magnesium salt) The portion of the total alkalinity dosage attributable to either sodium acetate or potassium acetate can be determined by first determining the total alkaline dosage, as described above. After determining the total alkaline dosage, the destructive analysis of the polymer sheet can be performed by Inductively Coupled Plasma Emission Spectroscopy (ICP) which produces a ppm concentration for potassium and a concentration of ppm for sodium. The alkaline dosage attributable to sodium acetate is defined herein as the total alkaline dosage multiplied by the ratio [ppm sodium / (ppm sodium + ppm potassium)]. The alkaline dosage attributable to potassium acetate is defined herein as the total alkaline dosage multiplied by the ratio [ppm potassium / (ppm sodium + ppm potassium)]. By virtue of the present invention, it is now possible to provide a sheet of poly (vinyl butyral) and other polymer sheets with superior characteristics of resistance to deterioration. The higher dosages of sodium acetate and sodium acetate and a magnesium salt described herein, provide better stability, particularly in environments in which the polymer sheet is exposed to a high temperature and water content, without altering the unacceptable form the adhesion qualities of the polymer sheet. Although the invention has been described with reference to examples of modalities, the skilled person will understand that different changes and equivalents could be substituted for elements thereof, without departing from the scope of the invention. In addition, many modifications could be made to adapt a particular material or situation to the teachings of the invention, without deviating from the essential scope of the same. Therefore, it is intended that the invention not be limited to the particular embodiments described as the best mode contemplated for carrying out this invention., but that the invention includes all the modalities that are within the scope of the appended claims. It will additionally be understood that any of the scales, values or features provided for any single component of the present invention, can be used interchangeably with any scale, value or feature provided for any of the other components of the invention, when there is compatibility, to form a modality that has defined values for each of the components, as they are provided throughout the present. For example, a polymer sheet can be formed comprising sodium acetate at any of the scales provided in addition to any scale provided for the plasticizer, where appropriate, to form many permutations that are within the scope of the present invention, but which would result difficult to list. Any of the claims is for illustrative purposes only and should not be construed as limiting the claimed invention to any of the particular embodiments. Each of the references, including the articles of journals, patents, applications and books, to which reference is made herein is incorporated by reference herein in its entirety.

Claims (3)

1. NOVELTY OF THE INVENTION CLAIMS 1. - A polymer sheet comprising: plasticized poly (vinyl butyral), sodium acetate and a magnesium salt, wherein the dosage of said magnesium salt is at least 4, wherein the alkalinity dosage attributable to said acetate of sodium is at least 20 and wherein the proportion of said dosage of said magnesium salt with respect to the total alkalinity dosage is at least 0.2.
2. 2. The polymer sheet according to claim 1, further characterized in that said alkalinity dosage attributable to said sodium acetate is at least 30.
3. 3. The polymer sheet according to claim 1, further characterized because said dosage of alkalinity attributable to said sodium acetate is at least 40. 4.- The polymer sheet according to claim 1, further characterized in that said alkalinity dosage attributable to said sodium acetate is at least 50. 5. The polymer sheet according to claim 1, further characterized in that said dosage of said magnesium salt is at least 8. 6. - The polymer sheet according to claim 1, further characterized in that said dosage of said magnesium salt is at least 12 7 - The polymer sheet according to claim 1, further characterized in that said proportion of said dosage of said magnesium salt with respect to said total alkalinity dosage is at least 0.3. 8. The polymer sheet according to claim 1, further characterized in that said proportion of said dosage of said magnesium salt with respect to said total alkalinity dosage is at least 0.4. 9. The polymer sheet according to claim 1, further characterized in that said magnesium salt is magnesium bis (2-ethylbutyrate). 10. A polymer sheet comprising: plasticized poly (vinyl butyral), sodium acetate, potassium acetate and a magnesium salt, wherein the dosage of said magnesium salt is at least 9.0, wherein the dosage of total alkalinity is at least 20, wherein the proportion of said dosage of said magnesium salt with respect to said total alkalinity dosage is at least 0.2 and wherein the proportion of parts per million of potassium with respect to Parts per million of sodium is less than 1.0. 11. - The polymer sheet according to claim 10, further characterized in that said alkalinity dosage is at least 30. 12. The polymer sheet according to claim 10, further characterized in that said alkalinity dosage is at least 40. 13.- The polymer sheet according to claim 10, further characterized in that said alkalinity dosage is at least 50. 14.- The polymer sheet according to the claim 10, further characterized in that said dosage of said magnesium salt is at least 8. The polymer sheet according to claim 10, further characterized in that said dosage of said magnesium salt is at least 10. 16. The polymer sheet according to claim 10, further characterized in that said proportion of said dosage of said magnesium salt with respect to said total alkalinity dosage is at least 0.3. 17.- The polymer sheet in accordance with the claim 10, further characterized in that said proportion of said dosage of said magnesium salt with respect to said total alkalinity dosage is at least 0.4. 18. - The polymer sheet according to claim 10, further characterized in that the proportion of parts per million of said sodium with respect to or parts per million of said potassium is less than 0.8. 19. The polymer sheet according to claim 10, further characterized in that said magnesium salt is magnesium bis (2-ethylbutyrate). 20. A method for manufacturing a polymer sheet comprising: forming a poly (vinyl butyral) resin, wherein said resin comprises sodium acetate and a magnesium salt; adding a plasticizer to said resin to form a cast; and forming said polymer sheet with said casting, wherein the dosage of said magnesium salt is at least 4, wherein the dosage of alkalinity attributable to said sodium acetate is at least 20 and wherein the proportion of said dosage of said magnesium salt with respect to the total alkalinity dosage is at least 0.2. 21. A laminated glass panel comprising: a glass panel and a polymer sheet, wherein said polymer sheet comprises: plasticized poly (vinyl butyral), sodium acetate and a magnesium salt, wherein the dosage of said magnesium salt is at least 4, wherein the dosage of alkalinity attributable to said sodium acetate is at least 20 and wherein the proportion of said dosage of said magnesium salt with respect to the total alkalinity dosage It is at least 0.2.