PVC compositions containing coprecipitated rare earth additives

Abstract

The PVC compositions disclosed herein contain a PVC resin, a coprecipitated rare earth additive, and an inorganic flame retardant. These PVC compositions exhibit improved flame retardancy, with a UL94 rating of V-2 or higher for samples approximately 0.8 mm thick. The coprecipitated rare earth additive contains a rare earth and one or more of zinc, aluminum, and magnesium, and the coprecipitated rare earth additive contains about 5 to about 95 wt. % of the rare earth, measured on an oxide basis. The inorganic flame retardant can be ATO, MDH, ATH, or a mixture thereof. The coprecipitated rare earth additive provides improved properties compared to the same PVC composition containing the components of the coprecipitated additive but added to the PVC composition as a blend of these components rather than as a coprecipitated additive.

Description

[Technical Field]

[0001]

[0000] Related Applications This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 383,661, filed November 14, 2022, the contents of which are incorporated herein by reference in their entirety.

[0001] The present invention relates to a polyvinyl chloride (PVC) composition containing a PVC resin, an inorganic flame retardant, and a coprecipitated rare earth additive, the PVC composition having a UL94 rating of V-2 or higher for a specimen about 0.8 mm thick. The coprecipitated rare earth additive improves the performance of the inorganic flame retardant additive and / or the flame retardancy and thermal stability of the PVC formulation. [Background technology]

[0002] Polyvinyl chloride (PVC) resin is a polymer made from vinyl chloride monomer. This resin is mixed with other ingredients to create PVC compositions or formulations, often simply referred to as PVC. These PVC compositions require specific properties, such as flame retardancy, color, thermal stability, malleability, and moldability, to name just a few. Other ingredients or additives in the composition can impart desired properties, and these ingredients / additives can be categorized as plasticizers, stabilizers, lubricants, fillers, and other functional additives. Additionally, certain amounts of each of these additional ingredients / additives can modify the desired properties of the PVC composition.

[0003] PVC compositions and products made from these PVC compositions generate hydrogen chloride gas during high-shear processing or as a direct result of a combustion event, which can corrode external equipment and automatically cause further degradation of the PVC. Antimony trioxide (ATO), magnesium dihydroxide (MDH), and aluminum trihydrate (often referred to as alumina trihydrate (ATH)) are used as flame retardants in PVC compositions. However, ATO is considered highly toxic and generates large amounts of smoke during a combustion event. The usefulness of ATH and MDH may be limited by their compatibility with certain PVC compositions, and they may only be added at relatively limited levels before adversely affecting the physical and aesthetic properties of the PVC composition and end-use products. While adopting "green" additives to reduce the content of these flame retardants or even eliminate them would be a significant advantage, they remain a challenge.

[0004] Other typical examples of flame retardant additives include halogenated organic compounds such as halogenated paraffins. These additives are also not considered "environmentally friendly" and are banned in some jurisdictions, such as Europe.

[0005] Accordingly, there remains a need for additives for PVC compositions that provide synergy with known flame retardants and / or additional thermal stability. It would be desirable to provide a synergistic flame retardant additive and / or heat stabilizer and / or acid scavenger and / or smoke suppressant (reducing smoke density, emissions, and acidity) to PVC compositions while reducing the amount of ATO due to its toxicity. This desirable additive must have excellent dispersibility in polymer and thermoplastic resin compositions and can be used to prepare flame-retardant plasticized PVC compositions with excellent flame retardancy and mechanical properties. Summary of the Invention

[0006] In one embodiment, disclosed herein is a polyvinyl chloride (PVC) composition comprising a PVC resin; an inorganic flame retardant selected from the group consisting of antimony trioxide (ATO), magnesium dihydroxide (MDH), aluminum trihydrate (ATH), and mixtures thereof; and a coprecipitated rare earth additive comprising a rare earth and one or more of zinc, aluminum, and magnesium, wherein the coprecipitated rare earth additive comprises about 5 to about 95 wt. % of the rare earth, measured on a rare earth oxide basis. The PVC composition comprises 100 phr of PVC resin and has a UL94 rating of V-2 or better for a specimen about 0.8 mm thick. In a specific embodiment, the PVC composition has a UL94 rating of V-0 for a specimen about 0.8 mm thick.

[0007] In certain embodiments, the rare earth compound is yttrium, lanthanum, cerium, neodymium, praseodymium, or a mixture thereof. In certain embodiments, the precipitated rare earth additive comprises yttrium and zinc; yttrium, zinc, and aluminum; yttrium, zinc, and magnesium; or yttrium, zinc, magnesium, and aluminum.

[0008] The combination of the coprecipitated rare earth additive and the inorganic flame retardant forms a synergistic interrelationship. Thus, a PVC composition containing a rare earth compound can contain a lower amount of inorganic flame retardant than would be required in the absence of the rare earth compound to achieve the desired flame retardancy (UL94 rating of V-2 or better for a sample about 0.8 mm thick). Thus, a PVC composition containing a coprecipitated rare earth additive can contain less inorganic flame retardant (e.g., ATO) than an identical PVC composition without the coprecipitated rare earth additive and still achieve the same UL94 rating (i.e., a UL94 rating of V-2 or better for a sample about 0.8 mm thick, in some embodiments, a UL94 rating of V-0 for a sample about 0.8 mm thick).

[0009] Furthermore, PVC compositions containing the coprecipitated rare earth additive exhibit improved properties, including flame retardancy, compared to identical PVC compositions containing the components of the coprecipitated additive, but in which these components are added to the PVC composition as a blend rather than as a coprecipitating agent.

[0010] In another embodiment, a PVC composition comprises PVC resin; ATO; and a coprecipitated rare earth additive consisting of a rare earth, zinc, and optionally aluminum, magnesium, or a mixture thereof, wherein the coprecipitated rare earth additive comprises from about 5 to about 95 weight percent rare earth, measured on a rare earth oxide basis. The PVC composition comprises 100 phr of PVC resin. The PVC composition has a UL94 rating of V-0, V-1, or V-2 for a 0.8 mm thick specimen, and contains less ATO than an identical PVC composition without the coprecipitated rare earth additive to achieve the same UL94 rating. In certain of these embodiments, the PVC composition has a UL94 rating of V-0 for a 0.8 mm thick specimen. In certain of these embodiments, the coprecipitated rare earth additive comprises yttrium. In certain of these embodiments, the PVC composition comprises ATO and the coprecipitated rare earth additive in a combined amount of from about 3 phr to about 10 phr.

[0011] In certain embodiments of any of the above embodiments, the PVC composition may comprise about 0 phr of chlorinated paraffins. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a graph illustrating the thermogravimetric analysis of yttrium hydroxide synthesized in Example 1.

[0013] [Figure 2] FIG. 1 is a differential scanning calorimetry plot of the yttrium hydroxide synthesized in Example 1 over a temperature range relevant to flame retardancy.

[0014] [Figure 3] FIG. 1 is a differential scanning calorimetry plot of the materials of Examples 2B-2E over a temperature range relevant to flame retardancy.

[0015] [Figure 4] FIG. 1 is a differential scanning calorimetry plot of the materials of Examples 3A-3F over a temperature range relevant to flame retardancy.

[0016] [Figure 5] FIG. 1 is a differential scanning calorimetry plot of the materials of Examples 4A-4F over a temperature range relevant to flame retardancy.

[0017] [Figure 6] FIG. 1 is a differential scanning calorimetry plot of the materials of Examples 5 and 6 over a temperature range relevant to flame retardancy.

[0018] [Figure 7] 1 is a graph of surface area and drying temperature of the material of Example 5.

[0019] [Figure 8] 1 is a graph of surface area and drying temperature of the materials of Example 6. DETAILED DESCRIPTION OF THE INVENTION

[0020] Before the compositions, articles, and methods are disclosed and described, it is to be understood that the disclosure is not limited to the specific structures, process steps, or materials disclosed herein but extends to equivalents thereof as recognized by those skilled in the art. It is also to be understood that the terminology used herein is used only for the purpose of describing particular embodiments and is not intended to be limiting. It should be noted that, as used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, references to "coprecipitated rare earth additives" or "inorganic flame retardants" or "flame retardants" should not be construed as limiting quantities or sources as singular or plural; references to a "step" may include multiple steps; references to "producing" or "products" of a reaction or process should not be construed as all of the products of the reaction / process; and references to "processing" may include references to one or more of such processing steps. Thus, processing steps may include multiple or repeated processing of similar materials / streams to produce the specified processed products.

[0021] Numerical values ​​containing "about" or "approximately" include typical experimental variance. As used herein, the terms "about" and "approximately" are used interchangeably and refer to within a statistically relevant range of a stated weight percentage, surface area, concentration range, time frame, distance, molecular weight, temperature, pH, and the like. Such ranges may be within 10-fold, typically within 10%, and even more typically within 5% of the stated value or range. Sometimes, such ranges may be within the experimental error typical of the standard method used to measure and / or determine a given value or range. The allowable variation encompassed by the term "about" depends on the particular system under study and can be readily understood by one of ordinary skill in the art. Whenever a range is recited within this application, at least every integer within that range is contemplated as an embodiment of the invention.

[0022] Polyvinyl chloride (PVC) resin is a polymer made from vinyl chloride monomer that is mixed with other ingredients to make PVC compositions or formulations that are used in end-use PVC products.

[0023] It should be noted that the terms flame and fire are used interchangeably herein when describing the properties of PVC compositions and when describing the additives that impart these properties to PVC.

[0024] ATH can be referred to interchangeably as alumina trihydrate, aluminum trihydrate, or aluminum trihydroxide, and these names can be used interchangeably to mean the same thing when describing this additive. Additionally, flame retardant and flame retardant are used interchangeably herein.

[0025] The present disclosure relates to polyvinyl chloride (PVC) compositions that have desirable properties, including flame retardancy and good thermal stability, and contain reduced amounts of inorganic flame retardants. The PVC compositions disclosed herein can be in rigid or flexible forms. The PVC compositions of the present disclosure include a PVC resin, an inorganic flame retardant, and a coprecipitated rare earth additive. The inorganic flame retardant in these compositions can be antimony trioxide (ATO), magnesium dihydroxide (MDH), aluminum trihydrate (ATH), or a mixture thereof. The coprecipitated rare earth additive is composed of a rare earth and one or more of zinc, aluminum, and magnesium. The composition contains 100 phr of PVC resin and has a UL94 rating of V-2 or higher for a sample about 0.8 mm thick. In certain embodiments, the PVC composition contains about 1 phr to about 10 phr of the coprecipitated rare earth additive.

[0026] The coprecipitated rare earth additive is composed of a rare earth and one or more of zinc, aluminum, and magnesium, and contains about 5% to about 95% by weight of rare earth, measured on a rare earth oxide basis. The rare earth can be a rare earth hydroxide, oxide, or mixture thereof. The zinc can be zinc oxide, zinc hydroxide, or mixture thereof. The aluminum can be aluminum hydroxide, aluminum oxide, or mixture thereof. The magnesium can be magnesium oxide, magnesium hydroxide, or mixture thereof.

[0027] As used herein, "coprecipitation" or "coprecipitant" means that the individual components (i.e., rare earth and one or more of zinc, aluminum, and magnesium) are combined as solutions and then precipitated together to form a solid (i.e., a coprecipitate). In contrast, a "blend" is when the individual components (i.e., rare earth and one or more of zinc, aluminum, and magnesium) are combined as solids and mixed together as solids to form the "blend."

[0028] As described herein, the co-precipitating additives impart surprisingly good properties to a PVC composition as compared to the same PVC composition containing the components of the co-precipitating additive, but added to the PVC composition as a blend of these components rather than the co-precipitating agent.

[0029] In certain embodiments, the coprecipitated rare earth additive is comprised of a rare earth, zinc, and optionally magnesium, aluminum, or a mixture thereof. In certain embodiments, the coprecipitated rare earth additive is comprised of a rare earth and zinc. In other certain embodiments, the coprecipitated rare earth additive is comprised of a rare earth, zinc, and magnesium. In even more certain embodiments, the coprecipitated rare earth additive is comprised of a rare earth, zinc, and aluminum. In even more certain embodiments, the coprecipitated rare earth additive is comprised of a rare earth, zinc, magnesium, and aluminum. In certain of these embodiments, the rare earth is yttrium. In those embodiments containing zinc, another advantage of the PVC compositions of the present invention is that the coprecipitated rare earth additive can contain zinc within the coprecipitated additive without blackening at high temperatures.

[0030] Without being bound by theory, it is believed that the combination of a coprecipitated rare earth additive and an inorganic flame retardant is synergistic. PVC compositions containing the coprecipitated rare earth additive contain a lower amount of inorganic flame retardant than would be required in the absence of the coprecipitated rare earth additive, yet achieve the desired flame retardancy (i.e., a UL94 rating of V-2 or higher for a sample approximately 0.8 mm thick). Furthermore, PVC compositions containing the coprecipitated rare earth additive exhibit improved properties, including flame retardancy, compared to identical PVC compositions containing the components of the coprecipitated additive, but in which a blend of these components, rather than the coprecipitated additive, is added to the PVC composition.

[0031] As disclosed above, the coprecipitated rare earth additive is comprised of rare earths in an amount of about 5 to about 95 wt. % measured on a rare earth oxide basis. In certain embodiments, the coprecipitated rare earth additive is comprised of rare earths in an amount of about 5 to about 90 wt. % measured on a rare earth oxide basis. In certain embodiments, the coprecipitated rare earth additive is comprised of rare earths in an amount of about 10 wt. % to about 50 wt. % measured on a rare earth oxide basis, or rare earths in an amount of about 15 wt. % to about 45 wt. % measured on a rare earth oxide basis.

[0032] In the coprecipitated rare earth additive, the rare earth is a rare earth hydroxide, a rare earth oxide, or a mixture thereof. The rare earth is yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), cerium (Ce), or a mixture thereof. In a specific embodiment, the rare earth is yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), or a mixture thereof. In certain embodiments, the rare earth is yttrium (hydroxide and / or oxide), lanthanum (hydroxide and / or oxide), cerium (hydroxide and / or oxide), or mixtures thereof.

[0033] In certain embodiments, the rare earth of the coprecipitated rare earth additive is yttrium, lanthanum, cerium, neodymium, praseodymium, or a mixture thereof. As described above, the rare earth can be in the form of a rare earth oxide, hydroxide, or a mixture thereof. In certain embodiments, the rare earth is yttrium. Thus, in certain embodiments, the rare earth in the coprecipitated additive is yttrium hydroxide, yttrium oxide, or a mixture thereof.

[0034] In certain embodiments where the rare earth is yttrium, the coprecipitated rare earth additive is composed of yttrium, zinc, and optionally magnesium, aluminum, or a mixture thereof. In certain of these embodiments, the coprecipitated rare earth additive is composed of yttrium and zinc. In other particular embodiments, the coprecipitated rare earth additive is composed of yttrium, zinc, and magnesium. In even more particular embodiments, the coprecipitated rare earth additive is composed of yttrium, zinc, and aluminum. In even more particular embodiments, the coprecipitated rare earth additive is composed of yttrium, zinc, magnesium, and aluminum.

[0035] In these embodiments of the specifically enumerated rare earths, the rare earths may further include minor amounts of any other rare earths. Rare earths are generally present as mixtures. In certain embodiments, the specifically enumerated rare earths may further include minor amounts of neodymium (Nd) and / or samarium (Sm). When present in minor amounts, these minor amounts are typically less than 5% by weight or trace amounts.

[0036] In all of these embodiments of the specifically recited rare earths above, the coprecipitated rare earth additive is comprised of from about 5 to about 95 weight percent rare earth, measured on a rare earth oxide basis, and in certain embodiments, from about 5 to about 90 weight percent rare earth, measured on a rare earth oxide basis. In certain embodiments, the coprecipitated rare earth additive is comprised of from about 10 to about 50 weight percent rare earth, measured on a rare earth oxide basis, or from about 15 to about 45 weight percent rare earth, measured on a rare earth oxide basis.

[0037] In some embodiments, the particle size of the coprecipitated rare earth additive allows the additive to be more easily incorporated into the PVC composition. In these embodiments, the coprecipitated rare earth additive may have a particle size of less than 10 microns. In certain of these embodiments, the coprecipitated rare earth additive has a particle size of about 0.1 microns to about 10 microns. If necessary, the particle size distribution can be modified by a grinding and separation process to create a more uniform particle size distribution. The particle sizes described herein are measured using a Malvern Mastersizer 2000. This particle size can be combined with any of the specifically listed embodiments of the coprecipitated rare earth additive.

[0038] Co-precipitated rare earth additives can have an increased surface area at elevated temperatures, allowing more of the additive's components to interact with the PVC degradation products, improving combustion suppression.

[0039] In the PVC compositions disclosed herein, the coprecipitated rare earth additive may be present in an amount of from about 1 phr to about 10 phr. In certain embodiments, the coprecipitated rare earth additive may be present in an amount of from about 1 phr to about 6 phr. These amounts of coprecipitated rare earth additive may be combined with any of the specifically recited embodiments of the coprecipitated rare earth additive.

[0040] As described herein, the addition of these coprecipitated rare earth additives to PVC compositions allows the PVC compositions to exhibit the desired and necessary flame retardancy while simultaneously allowing for reduced amounts of these inorganic flame retardants (e.g., ATO). Thus, the PVC compositions disclosed herein, while containing small amounts of these inorganic flame retardants (e.g., ATO), achieve the same UL94 rating as an identical PVC composition without the coprecipitated rare earth additive (i.e., a UL94 rating of V-2 or better for a sample about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for a sample about 0.8 mm thick). Furthermore, PVC compositions containing coprecipitated rare earth additives exhibit improved properties, including flame retardancy, compared to identical PVC compositions containing the components of the coprecipitated additive, but added to the PVC composition as a blend of these components rather than as a coprecipitated additive.

[0041] Within PVC compositions, coprecipitated rare earth additives are believed to release coordinated water species at temperatures above 200°C. These rare earths in the coprecipitated additives have the ability to retain water at high temperatures. Without being bound by theory, the release of water can cool and dilute the combustion process of the PVC composition and / or end-use PVC product. For PVC wiring in particular, water release in the 200-600°C temperature range is advantageous. The endothermic reaction results in the formation of an oxide layer that acts as an insulating barrier, inhibiting the release of gases that can contribute to the thermal decomposition of PVC. Without being bound by theory, the thermal stabilizing properties of the coprecipitated additives in PVC, which retard the release of corrosive HCl, are surprisingly key properties desirable in PVC compositions.

[0042] Another advantage of the PVC composition of the present invention is that the coprecipitated rare earth additive containing rare earth and zinc can enhance desirable flame retardancy without blackening at high temperatures. Typically, when zinc additives are used in PVC formulations, at high temperatures, the zinc compound reacts with the released HCl to form zinc chloride (ZnCl2). Zinc chloride is a strong Lewis acid, promoting crosslinking and carbonization reactions in PVC, resulting in blackening. Blackening of PVC at temperatures between 200 and 600°C impairs the appearance of the PVC. While zinc can impart flame retardancy to PVC, blackening adversely affects the appearance. Therefore, PVC compositions containing coprecipitated rare earth additives can contain zinc and enhance flame retardancy without blackening at high temperatures.

[0043] As described above, the inorganic flame retardant in these compositions is antimony trioxide (ATO), magnesium dihydroxide (MDH), aluminum trihydrate (ATH), or a mixture thereof. In certain embodiments, the inorganic flame retardant in these compositions is antimony trioxide (ATO). The inorganic flame retardant may be present in the PVC composition in an amount of from about 1 phr to about 60 phr. In the case of ATO, the ATO may be present in an amount of from about 1 phr to about 10 phr, and in certain embodiments, the ATO may be present in an amount of from about 1 phr to about 6 phr. There is interest in the PVC industry in PVC compositions that minimize the amount of these inorganic flame retardants (specifically ATO) while still achieving desirable flame retardancy and thermal stability.

[0044] In certain embodiments, the inorganic flame retardant is antimony trioxide (ATO). Thus, in certain embodiments, the PVC composition contains ATO. The combination of the coprecipitated rare earth additive with ATO allows the PVC composition to achieve the same UL94 rating (i.e., a UL94 rating of V-2 or better for a sample about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for a sample about 0.8 mm thick) with less ATO than the same PVC composition without the coprecipitated rare earth additive. While ATO is a highly effective flame retardant, it is considered highly toxic and produces large amounts of smoke during a combustion event. Therefore, minimizing the amount of ATO required to achieve a PVC composition with acceptable flame retardancy and thermal stability is an important advantage. Furthermore, PVC compositions containing the coprecipitated rare earth additive exhibit improved properties, including flame retardancy, compared to identical PVC compositions containing the components of the coprecipitated additive but added to the PVC composition as a blend of these components rather than as a coprecipitated additive.

[0045] In the PVC compositions of the present disclosure, the inorganic flame retardant, when ATO, is generally present in an amount of from about 1 phr to about 6 phr.

[0046] In certain embodiments, the inorganic flame retardant is MDH. Thus, in certain embodiments, the PVC composition contains MDH. When the inorganic flame retardant is MDH, it is generally present in an amount of about 15 phr to about 50 phr. In certain embodiments containing MDH, the PVC composition contains about 25 phr to about 50 phr of MDH. In other embodiments containing MDH, the PVC composition contains about 30 phr to about 50 phr of MDH. The usefulness of MDH may be limited by its compatibility with certain PVC compositions, and MDH may have a relatively limited amount of addition before adversely affecting the physical and aesthetic properties of the PVC product. By combining the coprecipitated rare earth additive with MDH, the PVC composition can contain less MDH than the same PVC composition without the coprecipitated rare earth additive and still achieve the same UL94 rating (i.e., a UL94 rating of V-2 or better for a sample about 0.8 mm thick; in some embodiments, a UL94 rating of V-0 for a sample about 0.8 mm thick). Furthermore, in certain of these embodiments comprising MDH and a coprecipitated rare earth additive, the PVC composition can contain about 0 phr of ATO (i.e., no ATO) and have a desirable UL94 rating (i.e., a UL94 rating of V-2 or better for a specimen about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for a specimen about 0.8 mm thick).

[0047] In another embodiment, the inorganic flame retardant is ATH. Thus, in certain embodiments, the PVC composition contains ATH. When the inorganic flame retardant is ATH, it is generally present in an amount of about 15 phr to about 50 phr. In certain embodiments containing ATH, the PVC composition contains about 25 phr to about 50 phr of ATH. In other embodiments containing ATH, the PVC composition contains about 30 phr to about 50 phr of ATH. The usefulness of ATH may be limited by its compatibility with certain PVC compositions. Also, ATH may be added in relatively limited amounts before adversely affecting the physical and aesthetic properties of the PVC product. The combination of the coprecipitated rare earth additive with ATH allows the PVC composition to contain less ATH than the same PVC composition without the coprecipitated rare earth additive and still achieve the same UL94 rating (i.e., a UL94 rating of V-2 or better for a specimen about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for a specimen about 0.8 mm thick). Furthermore, in certain of these embodiments comprising ATH and a coprecipitated rare earth additive, the PVC composition can contain about 0 phr of ATO (i.e., no ATO) and still have a desirable UL94 rating (i.e., a UL94 rating of V-2 or better for a specimen about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for a specimen about 0.8 mm thick).

[0048] In other embodiments, the inorganic flame retardant is a mixture of ATO and MDH and / or ATH. When the inorganic flame retardant is a mixture of MDH and / or ATH and ATO, the mixture is present in an amount of from about 16 phr to about 56 phr. This combination of the coprecipitated rare earth additive and the inorganic flame retardant allows the PVC composition to achieve the same UL94 rating (i.e., a UL94 rating of V-2 or better for a sample about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for a sample about 0.8 mm thick) with less ATO than an identical PVC composition without the coprecipitated rare earth additive.

[0049] The PVC compositions of the present invention exhibit the flame retardancy desired and necessary for the end use of the PVC composition, while at the same time allowing the reduction of these inorganic flame retardants (especially ATO) by adding the coprecipitated rare earth additive to the composition. The PVC compositions of the present invention also exhibit the thermal stability desired and necessary for the end use of the PVC composition, while at the same time allowing the reduction of these inorganic flame retardants by adding the coprecipitated rare earth additive to the composition. Furthermore, PVC compositions containing the coprecipitated rare earth additive exhibit improved properties, including flame retardancy, compared to identical PVC compositions containing the components of the coprecipitated additive, but in which these components are added to the PVC composition as a blend rather than as a coprecipitating agent.

[0050] The PVC compositions of the present disclosure exhibit desirable and necessary flame retardancy as measured and determined by the UL94 rating. UL94 is a plastic flammability standard published by Underwriters Laboratories (USA). This standard classifies plastics in six different categories, from least flame-retardant to most flame-retardant, depending on how the plastic burns in various orientations and thicknesses. The PVC compositions disclosed herein have a UL94 rating of V-2 or better for a sample about 0.8 mm thick (i.e., V-1 and V-0 are superior ratings above V-2). In some embodiments, the PVC compositions disclosed herein have a UL94 rating of V-0 for a sample about 0.8 mm thick. [Table 1]

[0051] In certain embodiments, the PVC compositions disclosed herein have a UL94 rating of V-2, V-1, or V-0 for a specimen having a thickness of about 0.8 mm. In certain embodiments, the PVC compositions disclosed herein have a UL94 rating of V-0 for a specimen having a thickness of about 0.8 mm.

[0052] The PVC composition disclosed herein contains 100 phr of PVC resin. An inorganic flame retardant and a coprecipitated rare earth additive are added to the PVC resin as additives to provide a PVC composition that can be used in a variety of end-use PVC products. As described above, the inorganic flame retardant and the coprecipitated rare earth additive interact synergistically such that the PVC composition contains a lower amount (phr) of inorganic flame retardant than would normally be required to achieve a UL94 rating of V-2 or better on a specimen approximately 0.8 mm thick. In certain embodiments, the PVC composition may also have a Congo Red stain at 200°C for about 90 to about 200 minutes. Furthermore, PVC compositions containing the coprecipitated rare earth additive exhibit improved properties, including flame retardancy, compared to identical PVC compositions containing the components of the coprecipitated additive but added to the PVC composition as a blend of these components rather than as a coprecipitated additive.

[0053] Thus, PVC compositions containing coprecipitated rare earth additives, while containing small amounts of these inorganic flame retardants (specifically ATO), achieve the same UL94 rating as identical PVC compositions without the coprecipitated rare earth additives (i.e., a UL94 rating of V-2 or better for samples about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for samples about 0.8 mm thick).

[0054] The polyvinyl chloride (PVC) composition disclosed herein comprises a PVC resin, an inorganic flame retardant selected from the group consisting of antimony trioxide (ATO), magnesium dihydroxide (MDH), aluminum trihydrate (ATH), and mixtures thereof, and a coprecipitated rare earth additive, the composition comprising 100 phr of PVC resin and having a UL94 rating of V-2 or better for a specimen approximately 0.8 mm thick. In certain embodiments, the PVC composition has a UL94 rating of V-0 for a specimen approximately 0.8 mm thick. The coprecipitated rare earth additive is as described herein and comprises a rare earth and one or more of zinc, aluminum, and magnesium, the coprecipitated rare earth additive comprising from about 5 to about 95 wt. % of the rare earth, measured on a rare earth oxide basis. The coprecipitated rare earth additive is included in all embodiments described herein.

[0055] Conventional PVC compositions containing ATO as an inorganic flame retardant contain more ATO than is necessary in the PVC compositions of the present invention to achieve a UL94 rating. Because ATO is considered highly toxic, it is advantageous to contain less ATO. The PVC compositions disclosed herein contain reduced amounts of ATO while achieving the same UL94 rating. In embodiments of PVC compositions in which ATO is the inorganic flame retardant, the ratio of ATO to coprecipitated rare earth additive can be from about 1:3 to about 3:1. In certain of these embodiments, the ratio of ATO to coprecipitated rare earth additive is from about 1:1 to about 1:2, and in certain embodiments, the ratio of ATO to coprecipitated rare earth additive is about 1:1.

[0056] In certain embodiments where the inorganic flame retardant is ATO, the PVC composition can comprise a combined total of about 3 phr to about 10 phr of ATO and the coprecipitated rare earth additive. In certain of these embodiments, the coprecipitated rare earth additive comprises yttrium as the rare earth. In certain embodiments, the PVC composition can comprise about 1 to about 3.5 phr of ATO and about 1 to about 4.5 phr of the coprecipitated rare earth additive, and in certain of these embodiments, the coprecipitated rare earth additive comprises yttrium as the rare earth.

[0057] In certain embodiments in which the inorganic flame retardant is ATO, the coprecipitated rare earth additive contains yttrium and zinc. In certain of these embodiments, the ratio of yttrium:zinc can be from about 90:10 to about 10:90, and the ratio of ATO:coprecipitated rare earth additive can be from about 1:3 to about 3:1. In certain of these embodiments, the ratio of ATO:coprecipitated rare earth additive is from about 1:1 to about 1:2, and in certain embodiments, the ratio of ATO:coprecipitated rare earth additive is about 1:1. The PVC composition can contain a combined ratio of about 3 phr to about 10 phr of ATO and coprecipitated rare earth additive, the additive containing yttrium and zinc. In any of these embodiments, the PVC composition can contain about 1 to about 3.5 phr of ATO and about 1 to about 4.5 phr of coprecipitated rare earth additive, the additive containing yttrium and zinc.

[0058] In certain embodiments where the inorganic flame retardant is ATO, the coprecipitated rare earth additive contains yttrium, zinc, and magnesium. In certain of these embodiments, the coprecipitated rare earth additive contains about 5% to about 90% by weight of yttrium, about 5% to about 50% by weight of zinc, and about 5% to about 90% by weight of magnesium, measured on a yttrium, zinc, and magnesium oxide basis. In these embodiments, the ratio of ATO to coprecipitated rare earth additive can be about 1:3 to about 3:1. In certain of these embodiments, the ratio of ATO to coprecipitated rare earth additive is about 1:1 to about 1:2, and particularly in some of these embodiments, the ratio of ATO to coprecipitated rare earth additive is about 1:1. In certain of these embodiments where the inorganic flame retardant is ATO and the coprecipitated rare earth additive contains yttrium, zinc, and magnesium, the ratio of yttrium, zinc, and magnesium can be about 40:20:40.

[0059] The PVC composition can include from about 3 phr to about 10 phr of ATO and a coprecipitated rare earth additive, the additive including yttrium, zinc, and magnesium. In any of these embodiments, the PVC composition can include from about 1 to about 3.5 phr of ATO and from about 1 to about 4.5 phr of a coprecipitated rare earth additive, the additive including yttrium, zinc, and magnesium.

[0060] In certain embodiments where the inorganic flame retardant is ATO, the coprecipitated rare earth additive contains yttrium, zinc, and aluminum. In certain of these embodiments, the coprecipitated rare earth additive contains about 5% to about 90% by weight yttrium, about 5% to about 50% by weight zinc, and about 5% to about 90% by weight aluminum, measured on a yttrium, zinc, and aluminum oxide basis. In these embodiments, the ratio of ATO to coprecipitated rare earth additive can be about 1:3 to about 3:1. In certain of these embodiments, the ratio of ATO to coprecipitated rare earth additive is about 1:1 to about 1:2, and particularly in some of these embodiments, the ratio of ATO to coprecipitated rare earth additive is about 1:1. In certain of these embodiments where the inorganic flame retardant is ATO and the coprecipitated rare earth additive contains yttrium, zinc, and aluminum, the ratio of yttrium, zinc, and aluminum can be about 40:20:40.

[0061] The PVC composition can include a total of about 3 phr to about 10 phr of ATO and a coprecipitated rare earth additive, the additive containing yttrium, zinc, and aluminum. In any of these embodiments, the PVC composition can include about 1 to about 3.5 phr of ATO and about 1 to about 4.5 phr of a coprecipitated rare earth additive, the additive containing yttrium, zinc, and aluminum.

[0062] In other embodiments, the PVC composition contains MDH. In certain of these embodiments, the PVC composition contains from about 25 phr to about 50 phr of MDH and from about 3 phr to about 10 phr of the coprecipitated rare earth additive. In certain embodiments, the PVC composition contains from about 30 phr to about 50 phr of MDH. In certain embodiments, the PVC composition contains from about 3 phr to about 6 phr of the coprecipitated rare earth additive. In certain of these embodiments, the coprecipitated rare earth additive contains yttrium, zinc, and optionally magnesium, aluminum, or a mixture thereof.

[0063] The combination of the coprecipitated rare earth additive with MDH allows the PVC composition to contain less MDH than the same PVC composition without the coprecipitated rare earth additive and still achieve the same UL94 rating (i.e., a UL94 rating of V-2 or better for a sample about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for a sample about 0.8 mm thick). Furthermore, in certain of these embodiments comprising MDH and a coprecipitated rare earth additive, the PVC composition can contain about 0 phr of ATO (i.e., no ATO) and still have a desirable UL94 rating (i.e., a UL94 rating of V-2 or better for a sample about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for a sample about 0.8 mm thick).

[0064] In embodiments including MDH but no ATO, the PVC composition can contain from about 25 phr to about 50 phr of MDH and from about 3 phr to about 10 phr of the coprecipitated rare earth additive, or in certain embodiments, from about 30 phr to about 50 phr of MDH and / or from about 3 phr to about 6 phr of the coprecipitated rare earth additive. In certain of these embodiments, the coprecipitated rare earth additive contains yttrium, zinc, and optionally magnesium, aluminum, or mixtures thereof.

[0065] All embodiments of the PVC compositions of the present invention have a UL94 rating of V-2 or better for specimens about 0.8 mm thick. In certain embodiments, these PVC compositions have a UL94 rating of V-0 for specimens about 0.8 mm thick.

[0066] In addition to the inorganic flame retardant and coprecipitated rare earth additive, the PVC composition can further contain additional additives to impart desirable properties to the PVC. The selection of additives used in the PVC composition is governed by the performance requirements and specifications of the end-use finished product. For example, underground pipes, siding, venous tubing, and flooring have widely different performance requirements and require various additives to ensure that the PVC composition is suitable for the end-use product. Those skilled in the art will understand how to select additives based on the desired end-use. These additives can be fillers, plasticizers, colorants, stabilizers, lubricants, organic flame retardants, smoke suppressants, and mixtures thereof.

[0067] It should be noted that a particular additive may have multiple functions within a PVC composition, and one of ordinary skill in the art would recognize these multiple functions. As such, the additives having the functions described below are not limited as to their function, but rather are categorized by what one of ordinary skill in the art would consider to be the primary function of the inclusion of the particular additive.

[0068] The amounts of additional additives included in the PVC composition are also controlled by the performance requirements and / or physical properties desired for the finished end-use product and its specifications. The PVC compositions disclosed herein can include these additional additives in amounts such that they do not change the decomposition enthalpy of the composition by more than about 10% and therefore do not substantially affect the flame retardancy / fire resistance of the PVC composition imparted by the inorganic flame retardant in combination with the coprecipitated rare earth additive.

[0069] The additives and the amounts of these additives can be readily determined by one skilled in the art.

[0070] Fillers are primarily used to reduce cost, but may also impart desirable properties such as stiffness, flexural modulus, hardness, and density. Non-combustible fillers may also function, to a limited extent, as flame retardants or smoke suppressants. Fillers that may be included in the PVC compositions described herein include, for example, calcium carbonate, silica, silicates, clay, kaolin, magnesium silicate (talc), glass fiber, mica, wollastonite, sodium sulfate (NaSO), sodium sulfate decahydrate, barium sulfate (BaSO), alkaline earth metal sulfates, and the like. When present, fillers may be in an amount of from about 2 phr to about 400 phr.

[0071] Plasticizers can soften PVC compositions, reducing viscosity and improving processability, and improving impact resistance. Some non-flammable plasticizers may also function as flame retardants, to a limited extent. Plasticizers that can be included in the PVC compositions described herein include, for example, ATBC (acetyl tributyl citrate), DIDP (diisodecyl phthalate), DINP (diisononyl phthalate), DOP (dioctyl phthalate or bis(2-ethylhexyl) phthalate), DOTP (dioctyl terephthalate or bis(2-ethylhexyl) terephthalate), and TOTM (trioctyl trimellitate). Plasticizers typically include phthalates, trimelliates, adipates, adipate diesters, sebacates, benzoates, epoxidized soybean oil, organic phosphates, phosphate esters, polyesters, and the like. Examples of phosphates include triphenyl phosphate, trixylenyl phosphate, tricresyl phosphate, 2-ethylhexyl diphenyl phosphate (SANTICIZER 141), isodecyl diphenyl phosphate (SANTICIZER 148), octyl diphenyl phosphate (DISFLAMMOL DPO), 2-isopropylphenyl diphenyl phosphate, 3-isopropylphenyl diphenyl phosphate, 4-isopropylphenyl diphenyl phosphate, di(2-isopropylphenyl)phenyl phosphate, and the like. If present, plasticizers may be present in an amount of about 15 phr to about 150 phr. Rigid PVC contains no plasticizer (about 0 phr).

[0072] In certain embodiments, the PVC compositions described herein include a plasticizer selected from the group consisting of dioctyl terephthalate (DOTP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), and mixtures thereof. In specific embodiments of these embodiments, the PVC composition includes from about 35 phr to about 70 phr of the plasticizer. In certain embodiments, the PVC composition includes about 50 phr of dioctyl terephthalate (DOTP). These specific amounts and types of plasticizers can be included in any of the PVC embodiments described herein.

[0073] In certain embodiments of the rigid PVC composition, including any of the embodiments set forth herein, the PVC composition comprises about 0 phr of plasticizer.

[0074] The colorant can be a pigment and / or a dye and is selected based on the color stability, strength, specific gravity, transparency, and electrical properties of the PVC composition and end-use product. Pigments are generally insoluble in the PVC composition and can be inorganic or organic compounds. The pigment is dispersed throughout the PVC composition. The pigment is generally selected based on color stability and compatibility with the PVC composition. Dyes are generally soluble in the PVC composition and can be inorganic or organic compounds. Pigments that can be included in the PVC compositions described herein include, for example, inorganic and organic pigments. Inorganic pigments include, for example, titanium dioxide (TiO), lead chromate, lead sulfochromate, iron oxide, and ultramarine blue (sulfur-containing sodium aluminum silicate). Organic pigments include, for example, carbon black, copper phthalocyanine, diazo condensation products, diazo compounds, polycyclic compounds such as dioxazines, and monoazo compounds such as quinacridones, isoindolinones, and benzimidazolones. When present, colorants may be in an amount of from about 1 phr to about 10 phr. When present, pigments may be in an amount of from about 1 phr to about 10 phr. When present, dyes may be in an amount of from about 1 phr to about 10 phr.

[0075] Stabilizers are commonly used PVC additives. They help prevent the initial release of hydrogen chloride, the elimination of unstable chlorine and carbenium ions, autoxidation, and the addition of polyene sequences, all of which contribute to the chain reaction of degradation. Stabilizers can also increase the PVC composition's resistance to sunlight, weathering, and heat aging, which can have a significant impact on the formulation's physical properties and cost. Stabilizers can be supplied in the form of application-specific blends, where the primary components can be metal soaps, metal salts, and organometallic compounds. The choice of heat stabilizer depends on many factors, including the technical requirements of the PVC product, regulatory approval requirements, and cost.

[0076] Stabilizers that may be included in the PVC compositions described herein include, for example, antioxidants, antiozonants, light stabilizers, quenchers, acid scavengers, and the like.

[0077] Examples of antioxidants include phenolic antioxidants, analogs of phloretic acid, phosphite esters, phosphites, tri(2,4-di-tert-butylphenyl)phosphite, and thioethers.

[0078] Examples of antiozonants include p-phenylenediamine.

[0079] Examples of light stabilizers include hindered amine light stabilizers (HALS), benzotriazoles, benzophenones, organic nickel compounds, and nickel phenolates.

[0080] Examples of acid scavengers include metal soaps, barium stearate, calcium stearate, hydocalumite, calcium oxide, zinc oxide, magnesium oxide, tin, lead, mono- and di-alkyltin salts, and thioacid half esters such as thioglycolates, often known as thiotins or mercaptides.

[0081] Examples of common stabilizers that may impart one or more desirable properties are dicarboxylic acid half esters, often referred to as maleates or carboxylates, mono- or dialkyltin compounds, dibutyltin dichloride (DBTC), dimethyltin dichloride (DMTC), monobutyltin trichloride (MBT), monomethyltin trichloride (MMT), tetrabasic lead sulfate, tribasic lead sulfate, dibasic lead phosphite, dibasic lead phthalate, dibasic lead stearate, lead stearate, and the like.

[0082] When present, stabilizers may be in an amount of from about 0.5 phr to about 70 phr. In certain embodiments, stabilizers may be in an amount of from about 0.5 phr to about 10 phr.

[0083] Lubricants are added either externally or internally to reduce friction by polymer chain slippage (internally) or between the PVC composition and an exterior surface. Lubricants that can be included in the PVC compositions described herein include, for example, fatty acids, waxes, hydrocarbon waxes, polyethylene waxes, glyceryl dioleate, glyceryl monostearate, zinc laurate, glycerol diol, calcium hydroxystearate, EBS ethylene bis(stearamide), hydrogenated castor oil, stearyl stearate, sodium stearyl fumarate, magnesium stearate, zinc stearate, and the like. When present, the lubricant may be in an amount of about 0.1 phr to about 1 phr.

[0084] Organic flame retardants that may be included in the PVC compositions described herein include, for example, chlorinated paraffins and brominated organic compounds (such as polybrominated diphenyl ethers, polybrominated biphenyls, brominated cyclic hydrocarbons, etc.) When present, the organic flame retardants may be present in an amount of from about 1 phr to about 25 phr.

[0085] In certain embodiments, the PVC compositions described herein, including any of the specific embodiments, comprise an organic flame retardant, and in these certain embodiments, the organic flame retardant is one or more chlorinated paraffins. In these embodiments, the chlorinated paraffins may be present in an amount from about 1 phr to about 25 phr.

[0086] However, these halogenated organic flame retardant additives, specifically chlorinated paraffins, are not considered "environmentally friendly." In some jurisdictions, such as within Europe, the use of these chlorinated paraffins is prohibited. Therefore, in certain embodiments of the PVC compositions disclosed herein, including any of the specific embodiments, the compositions contain about 0 phr of chlorinated paraffins (i.e., no chlorinated paraffins). An advantage of the PVC compositions of the present invention is that these PVC compositions can achieve a UL94 rating and do not require these chlorinated paraffins.

[0087] Smoke suppressants that may be included in the PVC compositions described herein include, for example, ammonium octamolybdate, molybdenum trioxide, zinc borate (2ZnO 3B 2 O 3 ·3.5H 2 O, or ZnO 2B 2 O 3 ·2H 2 O, or 2ZnO 2B 2 O 3 ·3H 2 O), barium borate, copper oxalate, zinc stannate (ZnSnO 3 ), zinc hydroxystannate (ZnSn(OH) 6 ), zinc sulfide, and the like. Zinc hydroxystannate may also have some flame retardant properties. When present, the smoke suppressant may be present in an amount of from about 1 phr to about 20 phr.

[0088] Further optional additives may include one or more of the following:

[0089] Foaming agents or foaming agents, which are used to generate cellular structures or foams by decomposing with heat to release gas, include, for example, carbonate, ammonium carbonate, sodium carbonate, azo compounds, azodicarbonamide (azobisformamide), in amounts of about 0.3 phr to about 1 phr;

[0090] Microspheres;

[0091] Water repellent;

[0092] Impact modifiers with the function of improving toughness: for example, chlorinated polyethylene and acrylic copolymers, such as MBS (methyl acrylate butadiene styrene), MABS (methacrylate acrylonitrile-butadiene-styrene copolymer), NPDE (non-defined elastomer), etc.;

[0093] matting agents, such as methyl methacrylate;

[0094] a process oil / base, such as paraffin oil in an amount of about 1 phr to about 2 phr;

[0095] Processing aids; and

[0096] Solvents and intermediates such as methyl ethyl ketone, methyl isobutyl ketone, and white spirit.

[0097] Those skilled in the art will understand how to select appropriate additives and the amounts (phr) of these additives to include to provide a PVC composition that meets the performance requirements and / or physical characteristics desired for the finished end-use product and its specifications. The end-use PVC product may also be dyed to meet desired physical characteristics.

[0098] These additional additives must be PVC formulation-friendly and exhibit good compatibility with other PVC composition components. Mechanical properties such as tensile strength and processability of the PVC product can be crucial.

[0099] The rare earths in the co-precipitated additives used in the PVC compositions described herein possess several advantageous properties as PVC additives, including: 1) significant endothermic decomposition to release water and form a fire-resistant oxide layer; 2) halogen-free; 3) non-toxic and stable; 4) non-volatile and chemically neutral; 5) aesthetically colorless; 6) readily available and economically viable; 7) easily processable to small particle sizes; 8) low solubility and leachability; 9) acid scavenging ability to scavenge HCl; 10) heat stabilization; and 11) smoke suppressant.

[0100] As noted above, the PVC compositions of the present disclosure have a UL94 rating of V-2 or better for a specimen having a thickness of about 0.8 mm. In certain embodiments, the PVC compositions disclosed herein have a UL94 rating of V-2, V-1, or V-0 for a specimen having a thickness of about 0.8 mm. In certain embodiments, the PVC compositions disclosed herein have a UL94 rating of V-0 for a specimen having a thickness of about 0.8 mm.

[0101] The PVC compositions of the present disclosure can also exhibit desirable thermal stability as measured by Congo Red at 200°C. The Congo Red test method determines the thermal stability of PVC compositions when processed at elevated temperatures. This method is applicable to all PVC compositions, copolymers, and products based thereon. The Congo Red test is conducted at a temperature of 200°C according to the procedure outlined in International Standard ISO 182-1. The time (in minutes) required for the material to decompose, as indicated by the evolution of hydrogen chloride, is determined by the color change of the Congo Red test paper. In certain embodiments, PVC compositions containing coprecipitated rare earth additives exhibit improved thermal stability as measured by Congo Red at 200°C compared to the same PVC composition containing the components of the coprecipitated additive, but added to the PVC composition as a blend of these components rather than as a coprecipitant.

[0102] In certain embodiments, the PVC compositions disclosed herein, including any of the specific embodiments described above, have a Congo Red at 200° C. of from about 90 minutes to about 200 minutes.

[0103] In certain embodiments, PVC compositions containing coprecipitated rare earth additives, while containing small amounts of these inorganic flame retardants (specifically ATO), achieve the same Congo red at 200°C as identical PVC compositions without the coprecipitated rare earth additives. In further embodiments, PVC compositions containing coprecipitated rare earth additives, while containing small amounts of these inorganic flame retardants (specifically ATO), have improved Congo red at 200°C as identical PVC compositions without the coprecipitated rare earth additives. Furthermore, PVC compositions with coprecipitated rare earth additives may exhibit improved Congo red at 200°C compared to identical PVC compositions containing the components of the coprecipitated additive, but compared to a blend of these components rather than the coprecipitating agent, added to the PVC composition.

[0104] The PVC compositions of the present disclosure may also exhibit a desirable limiting oxygen index (LOI), which indicates the flammability of the PVC composition in terms of the minimum concentration of oxygen required to enable the PVC composition to sustain a flame / burn. The limiting oxygen index (LOI) of the PVC compositions disclosed herein is determined in accordance with ASTM D2863. In certain embodiments, the PVC compositions disclosed herein, including any of the specific embodiments described above, have an LOI of about 20 to about 35. Furthermore, a PVC composition containing a coprecipitated rare earth additive may exhibit an improved LOI compared to an identical PVC composition containing the components of the coprecipitated additive, but added to the PVC composition as a blend of these components rather than as a coprecipitating agent.

[0105] The disclosed PVC compositions may further exhibit desirable smoke densities when measured in accordance with ASTM D2843-22 (https: / / www.astm.org / d2843-22.html). This fire test response test method encompasses a laboratory procedure for measuring and observing the relative amount of smoke obscuration produced by the combustion or decomposition of plastics, including PVC. It is intended to be used to measure the smoke-producing characteristics of plastics under controlled combustion or decomposition conditions. Measurements are made based on the light transmission loss through a collected volume of smoke produced under controlled, standardized conditions. In certain embodiments, PVC compositions containing coprecipitated rare earth additives may exhibit improved smoke densities when measured in accordance with ASTM D2843-22 compared to identical PVC compositions containing the components of the coprecipitated additive, but in which these components are added to the PVC composition as a blend rather than as a coprecipitating agent.

[0106] Without being bound by theory, the PVC compositions disclosed herein, including inorganic flame retardants in combination with coprecipitated rare earth additives, may be able to absorb heat generated during combustion by undergoing endothermic release upon heating, particularly across the temperature range relevant to the combustion of PVC compositions / products. For example, the coprecipitated rare earth additives disclosed herein release water upon heating. This endothermic release absorbs thermal energy from surrounding materials, slowing combustion, and the release of water further weakens combustion by limiting access to oxygen and cooling the surrounding materials. In some embodiments, the PVC compositions disclosed herein can interrupt the otherwise self-sustaining combustion cycle of PVC. As noted above, this can be an endothermic process, thereby reducing heat below the threshold required to sustain combustion of the PVC. In addition to absorbing heat through endothermic release, the water released during oxidation can further cool and dilute the oxygen needed for the combustion process.

[0107] The rare earths in the coprecipitated additives can also behave as Lewis acid catalysts, providing an acid-scavenging function by forming chlorinated Lewis acid catalysts. This action can absorb acidic gases, such as HCl, released during combustion of PVC compositions. Upon combustion, the rare earths in the coprecipitated additives can crosslink to form an insulating carbonaceous char layer. Their strong acid-scavenging properties can also isolate HCl gas from smoke within the char layer, thereby reducing the acidity of the smoke. Therefore, the rare earths in the coprecipitated additives may seal the PVC and suppress gas emissions from flammable components that would otherwise contribute to continued pyrolysis. In this way, flammable portions of the PVC can be effectively isolated from ignition sources upon heating and oxidation of the rare earths in the coprecipitated additives. In certain embodiments, the strong oxidizing properties of the rare earths in the coprecipitated additives can contribute to the reduction of chlorides during combustion by forming chloride intermediates stable up to 1000°C. This makes the rare earth coprecipitated additive an unexpectedly advantageous additive / component of the PVC compositions disclosed herein. PVC compositions containing coprecipitated rare earth additives exhibit improved properties, including flame retardancy, compared to identical PVC compositions containing the components of the coprecipitated additive, but in which a blend of these components, rather than the coprecipitating agent, is added to the PVC composition.

[0108] The coprecipitated rare earth additives allow for a reduced amount of inorganic flame retardant (specifically ATO) to be used while achieving the same UL94 rating as the same PVC composition without the rare earth compound (i.e., a UL94 rating of V-2 or better for samples about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for samples about 0.8 mm thick).

[0109] When PVC burns, a large amount of smoke is released / produced. If ATO is used as a flame retardant in PVC and the PVC burns, ATO can react with the released HCl to ultimately form antimony trichloride. Antimony trichloride is volatile, with a boiling point of 283°C. This results in increased smoke levels when ATO is present. Because ATO is toxic and is released in smoke, it is desirable to reduce the amount of smoke, especially when using ATO in PVC compositions. The coprecipitated rare earth additives disclosed herein enable the reduction of ATO, thereby reducing the amount of smoke as well as the amount of ATO in the smoke produced. Furthermore, the smoke is not solely due to the presence of ATO. The coprecipitated rare earth additives also reduce smoke by reacting with compounds released in a combustion event, either by acting as Lewis acids or by adsorption, which further aids in smoke reduction. Thus, the coprecipitated rare earth additives enable a reduction in the amount of smoke, and in certain embodiments, a PVC composition including a coprecipitated rare earth additive may exhibit improved smoke density, as measured according to ASTM D2843-22, compared to an identical PVC composition containing the components of the coprecipitated additive, but where these components are added to the PVC composition as a blend rather than as a coprecipitant.

[0110] In one particular embodiment of a PVC composition, the PVC composition comprises a PVC resin; ATO; and a coprecipitated rare earth additive consisting of a rare earth, zinc, and optionally aluminum, magnesium, or a mixture thereof, wherein the coprecipitated rare earth additive comprises about 5 to about 95 wt. % of the rare earth, measured on a rare earth oxide basis. In one particular embodiment, the rare earth is yttrium. The PVC composition comprises 100 phr of PVC resin and has a UL94 rating of V-0, V-1, or V-2 for a 0.8 mm thick specimen, and the PVC composition contains less ATO than a PVC composition without the coprecipitated rare earth additive to achieve the same UL94 rating. In one particular embodiment, the PVC composition comprises a combined amount of ATO and the coprecipitated rare earth additive in an amount of about 3 phr to about 10 phr. In one particular embodiment, the PVC composition has a UL94 rating of V-0 for a 0.8 mm thick specimen. Additionally, the PVC composition may also have a Congo Red at 200°C for about 90 minutes to about 200 minutes.

[0111] This embodiment can include any of the ratios of ATO to coprecipitated rare earth additive and coprecipitated rare earth additive compositions described herein. Further, in certain of these embodiments, the PVC composition can include from about 1 to about 3.5 phr of ATO and from about 1 to about 4.5 phr of coprecipitated rare earth additive.

[0112] These particular embodiments can further include one or more of the additives described herein. Thus, these particular PVC compositions can further include an additive selected from the group consisting of fillers, plasticizers, colorants, stabilizers, lubricants, organic flame retardants, smoke suppressants, and mixtures thereof. These additives are as described above.

[0113] In certain embodiments of this particular PVC composition, the composition contains about 0 phr of chlorinated paraffins (ie, contains no chlorinated paraffins).

[0114] In another specific embodiment of the PVC composition, the PVC composition comprises 100 phr of PVC resin; about 25 phr to about 50 phr of MDH; and about 3 phr to about 10 phr of a coprecipitated rare earth additive consisting of a rare earth, zinc, and optionally aluminum, magnesium, or a mixture thereof, wherein the coprecipitated rare earth additive comprises about 5 to about 95 wt. % of the rare earth, measured on a rare earth oxide basis. In certain of these specific embodiments, the rare earth is yttrium. This PVC composition comprises 100 phr of PVC resin and has a UL94 rating of V-0, V-1, or V-2 for a sample about 0.8 mm thick. In certain embodiments, this PVC composition has a UL94 rating of V-0 for a sample about 0.8 mm thick. Furthermore, this PVC composition may also have Congo Red at 200°C for about 90 minutes to about 200 minutes.

[0115] By combining the coprecipitated rare earth additive with MDH, the PVC composition can contain less MDH than the same PVC composition without the coprecipitated rare earth additive and still achieve the same UL94 rating (i.e., a UL94 rating of V-2 or better for a sample about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for a sample about 0.8 mm thick). Furthermore, in certain of these embodiments comprising MDH and a coprecipitated rare earth additive, the PVC composition can contain about 0 phr of ATO (i.e., no ATO) and still have a desirable UL94 rating (i.e., a UL94 rating of V-2 or better for a sample about 0.8 mm thick, and in some embodiments, a UL94 rating of V-0 for a sample about 0.8 mm thick). These embodiments with MDH can include any of the coprecipitated rare earth additive compositions described herein.

[0116] In a specific embodiment comprising MDH and about 0 phr of ATO (i.e., no ATO), the PVC composition may contain about 25 phr to about 50 phr of MDH and about 3 phr to about 6 phr of the coprecipitated rare earth additive.

[0117] In other specific embodiments comprising MDH and about 0 phr of ATO (i.e., no ATO), the PVC composition may contain about 30 phr to about 50 phr of MDH and about 3 phr to about 6 phr of the coprecipitated rare earth additive.

[0118] These particular embodiments can further include one or more of the additives described herein. Thus, these particular PVC compositions can further include an additive selected from the group consisting of fillers, plasticizers, colorants, stabilizers, lubricants, organic flame retardants, smoke suppressants, and mixtures thereof. These additives are as described above.

[0119] Any of the embodiments of the PVC compositions disclosed herein can be used in a variety of end-use products known to those skilled in the art. These types of products include, for example, window frames, doors and door frames, drain pipes, water pipes, plumbing pipes, roofing, siding, residential and automotive trim, and flooring. Additional products include plastic bottles, packaging, cling films, and credit, bank, or membership cards. Further products include electrical cable insulation or housings, medical devices, blood storage bags, cable and wire insulation, fashion and footwear, inflatable products, and vinyl records. The PVC compositions can be included in coated fabrics for protective coatings. Further PVC products include shower curtains and signs. Further PVC products include sporting goods such as tents, kayaks, and climbing equipment.

[0120] As described herein, one of ordinary skill in the art will understand how to select the additional additives and the amounts of those additives to include to provide a PVC composition that meets the performance requirements and / or physical characteristics desired for these end-use finished products and their corresponding specifications.

[0121] Preparation of rare earth co-precipitated additives The coprecipitated rare earth additive is prepared by homogeneously mixing aqueous solutions of the individual components of the coprecipitated additive. As described herein, the coprecipitated additive includes a rare earth and one or more of zinc, aluminum, and magnesium. Thus, an aqueous solution of rare earths is prepared from soluble rare earth salts. To this rare earth solution, soluble salts of one or more of zinc, aluminum, and magnesium are added. Soluble salts include chlorides and nitrates. These soluble salts of one or more of zinc, aluminum, and magnesium can be added as their salts or as an aqueous solution. The concentration of the aqueous salt solution used can be about 0.0005 to about 3 mol / L.

[0122] The amounts of rare earth, zinc, aluminum, and magnesium are selected to achieve the desired ratios of components in the co-precipitation additive, including any of those described herein. The rare earth solution and one or more of the zinc, aluminum, and magnesium solutions are stirred at a temperature of about 0°C to about 90°C for about 5 minutes to about 3 hours.

[0123] The resulting solution is mixed with a high pH solution (pH of about 8 to about 14, in certain embodiments, about 9 to about 10) of a base, such as NaOH or NH4OH, at about 0°C to about 90°C for about 5 minutes to about 3 hours. Upon mixing with the base, the pH increases and the additives described herein precipitate. In certain embodiments, upon mixing with the base, the pH increases to about 8 to about 14, and in certain embodiments, the pH increases to about 9 to about 10. The resulting coprecipitated rare earth additive is collected by filtering or decanting the mixture liquid.

[0124] The collected coprecipitated rare earth additive is washed with water to remove any remaining soluble salts. The collected coprecipitated rare earth additive can be washed with deionized water until the conductivity of the aqueous solution is less than 50 mS / cm, and in certain embodiments, less than 30 mS / cm. The resulting coprecipitated rare earth additive is optionally dried by heating to a temperature of about 60°C to about 250°C for about 1 hour to about 24 hours, during which time excess water evaporates. In certain embodiments, the resulting coprecipitated rare earth additive is dried by heating to a temperature of about 80°C to about 200°C for about 6 hours to about 15 hours. As described herein, the individual components of the coprecipitated rare earth additive are hydroxides, oxides, or mixtures thereof. The components of the coprecipitated rare earth additive are initially hydroxides, and depending on the temperature and time of drying, these hydroxides are partially or completely converted to oxides.

[0125] The processes for preparing the coprecipitated rare earth additives described herein are further illustrated by the following examples.

[0126] Preparation of PVC Composition Processes for preparing PVC compositions are well known in the art, and the PVC compositions disclosed herein can be prepared by any of these known processes. These processes are not limited by any particular steps or methods and can generally be any that result in a mixture of PVC resin, inorganic flame retardant, and coprecipitated rare earth additive in a suitable PVC composition. The coprecipitated rare earth additive and inorganic flame retardant can be first mixed together and mixed with any other additives before being added to the PVC resin. Alternatively, the PVC resin, coprecipitated rare earth additive, inorganic flame retardant, and optional additional additives can all be mixed together first and then processed to provide the PVC composition. The resulting mixture can be either homogeneous or heterogeneous. The process to provide the PVC composition typically further includes grinding and heating. This process may optionally include further downstream processing steps (e.g., drying). These processes for preparing the PVC compositions and thereafter the end-use products can include any of the processing steps commonly utilized to prepare PVC compositions and end-use products, so long as the desired physical characteristics of the PVC composition and end-use PVC are provided and maintained.

[0127] The PVC composition may be prepared by compounding equipment such as injection molding or extrusion techniques that provide a PVC composition with excellent dispersibility and thermomechanical properties.

[0128] example Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) data for the examples disclosed herein were obtained using a TA Instruments® Q600 SDT with simultaneous TGA-DSC operation. Each sample was heated from room temperature to 1000°C at a rate of 10°C / min using air as the inert gas at a rate of 90 mL / min and N2 balance gas at a flow rate of 10 mL / min. In some cases, the TGA and DSC data for each sample were normalized to reflect the sample's weight at 200°C to account for the weight loss expected from the sample during the polymer manufacturing process. The DSC data were further normalized to reflect each sample's decomposition enthalpy relative to the starting point at 200°C. Loss on ignition was measured by heating a weighed sample in a furnace at 1000°C for 1 hour and weighing the remaining solid. Surface area, pore radius, and pore volume were measured by the BET / BJH method (ASTM D3663-20). Particle size was measured using a Microtrac S3500. X-ray diffraction was performed using a Bruker D2 Phaser X-ray diffractometer. The half-width was used to determine the crystallite size. As understood, crystallite size is the size of individual crystals measured by XRD or TEM. Dxx size is the particle size measured by laser diffraction, which is composed of individual crystallites.

[0129] The limiting oxygen index (LOI) of each compound was determined to evaluate the flame retardancy of each sample according to ASTM D2863. LOI determines the flammability of a material based on the minimum concentration of oxygen required to enable the material to sustain candle-like burning behavior. The oxygen concentration is expressed as a volume percentage of oxygen in a flowing mixture of oxygen and nitrogen. In accordance with the ISO 4589 standard, rod-shaped samples measuring 12.5 mm x 100 mm and 3 mm thick were used. The samples were ignited from the top, and the burn time of the ignited samples was recorded under different oxygen concentrations to determine the minimum oxygen concentration required to maintain combustion for at least 3 minutes after the ignition flame was removed. A Fire Testing Technology (FTT) model device equipped with an oxygen analyzer was used for this test. The test was repeated up to five times for each compound until the LOI was determined with acceptable confidence. All samples were tested at the same temperature.

[0130] The Congo Red test was performed at a temperature of 200°C according to the procedure outlined in international standard ISO 182-1.

[0131] Smoke density was measured according to the procedure outlined in ASTM D2843-22.

[0132] Example 1. Synthesis of yttrium hydroxide Yttrium hydroxide was prepared by first preparing a Y(NO3)3 solution containing 250 mg of yttrium oxide equivalent / L. The Y(NO3)3 solution was then added to a solution of approximately 10 M NaOH or 5.5 M NH4OH at a ratio of at least approximately 6 moles of OH to 1 mole of metal. The precipitate was collected by filtration and washed with DI water until the conductivity of the aqueous filtrate was less than 30 mS / cm. The resulting cake was dehydrated by continued filtration. The precipitated hydroxide was then dried at 80-200 °C for 6 hours. This material was then ground in a jet mill.

[0133] The resulting solid was analyzed by TGA / DSC. Mass losses corresponding to the release of water were observed at 250, 390, and 460 °C, as shown in Figure 1. DSC reveals endothermic transitions at approximately 450 °C and 510 °C, corresponding to enthalpies of approximately 270 J / g and 155 J / g, respectively, as shown in Figure 2. Particle size measurements revealed D50 to be approximately 2.2 μm, D90 to be approximately 4.2 μm, and D100 to be approximately 7.3 μm. The loss on ignition was found to be 39.37%, indicating a % YO of 60.63%. The solid was further analyzed by X-ray diffraction, which revealed a crystallite size of 15.99 nm.

[0134] Examples 2A-2E. Additives containing yttrium, zinc, and co-precipitated yttrium and zinc Co-precipitated yttrium zinc additives were prepared by first preparing solutions containing dissolved Y(NO3)3 and dissolved Zn(NO3)2 at the concentrations listed in Table 2 to achieve various ratios of Y oxide to Zn oxide. This solution was then added to a solution of approximately 10 M NaOH or 5.5 M NH4OH at a ratio of at least approximately 6 moles of OH to 1 mole of metal (Y and Zn combined). The precipitate was collected by filtration and washed with DI water until the aqueous solution had a conductivity of less than 30 mS / cm. The resulting cake was dehydrated by continued filtration. The precipitate was then dried at 80-200 °C for 12 hours. The material was then ground in a jet mill.

[0135] The resulting solid was analyzed by TGA / DSC. A significant mass loss was observed between 200 and 600 °C. A significant endothermic peak was observed in the DSC between 200 and 600 °C (Figure 3). The peak enthalpy was calculated from the area under the observed peak. The enthalpies of the peaks between 200 and 600 °C were summed and reported in Table 2. The enthalpy over this temperature range for the Y hydroxide of Example 1 is listed for comparison. The enthalpy over this temperature range for commercially available Zn oxide was not measured, but is expected to be lower than about 100 J / g, since Zn oxide does not lose weight above about 250 °C. Particle size measurements revealed that 2B had a D50 of approximately 9.53 μm and a D90 of approximately 22.67 μm, 2C had a D50 of approximately 7.75 μm and a D90 of approximately 23.61 μm, and 2D had a D50 of approximately 13.08 μm and a D90 of approximately 28.81 μm. Loss on ignition measurements were performed to determine the metal oxide content. Loss on ignition for 2B was 10.8%, for 2C was 21.6%, and for 2D was 28.3%. Metal oxide content is calculated by subtracting the loss on ignition from 100. [Table 2]

[0136] Examples 3A-3F. Additives Containing Yttrium, Magnesium, and Co-Precipitated Yttrium and Magnesium Co-precipitated yttrium magnesium additives were prepared by first preparing solutions containing dissolved Y(NO) and dissolved Mg(NO) at the concentrations listed in Table 3 to achieve various ratios of Y oxide to Mg oxide. This solution was then added to a solution of approximately 10 M NaOH or 5.5 M NHOH at a ratio of at least approximately 6 moles of OH to 1 mole of metal (Y and Mg combined). The precipitate was collected by filtration and washed with DI water until the aqueous solution had a conductivity of less than 30 mS / cm. The resulting cake was dehydrated by continued filtration. The precipitate was then dried at 80–200°C for 12 hours. The material was then ground in a jet mill.

[0137] The resulting solid was analyzed by TGA / DSC. Significant mass loss was observed between 200 and 600 °C. A significant endothermic peak was observed between 200 and 600 °C in the DSC (Figure 4). Peak enthalpies were calculated from the areas under the observed peaks. The enthalpies of the peaks between 200 and 600 °C were summed and reported in Table 3. The enthalpies of commercially available MDH and the Y hydroxide of Example 1 are listed for comparison. Particle sizes were measured and found to be D50, D90, and D100 of 3B (approximately 1.966 μm, 4.032 μm, and 9.55 μm), respectively, and D50, D90, and D100 of 3E (approximately 2.036 μm, 3.729 μm, and 6.32 μm, respectively). Loss on ignition was measured to determine the metal oxide content. The loss on ignition for 3B was 37.6% and for 3E was 37.48%. The metal oxide content is calculated by subtracting the loss on ignition from 100. [Table 3]

[0138] The coprecipitated material has an enthalpy between 200 and 600°C that is higher than the sum of the individual components. As seen in Example 3B, the enthalpy is 1230 J / g, but the individual components are 20% Y hydroxide (452 ​​J / g) and 80% Mg oxide (669 J / g), i.e., 20% x 452 + 80% x 669 = 625 J / g.

[0139] Examples 4A-4F. Additives containing lanthanum, magnesium, and co-precipitated lanthanum and magnesium Co-precipitated lanthanum magnesium additives were prepared by first preparing solutions containing dissolved La(NO3)3 and dissolved Mg(NO3)2 at the concentrations listed in Table 4 to achieve various ratios of La oxide to Mg oxide. This solution was then added to a solution of approximately 10 M NaOH or 5.5 M NH4OH at a ratio of at least approximately 6 moles of OH to 1 mole of metal (La and Mg combined). The precipitate was collected by filtration and washed with DI water until the aqueous solution had a conductivity of less than 30 mS / cm. The resulting cake was dehydrated by continued filtration. The precipitate was then dried at 80-200 °C for 12 hours. The material was then ground in a jet mill.

[0140] The resulting solid was analyzed by TGA / DSC. A significant mass loss was observed between 200 and 600 °C. A significant endothermic peak was observed between 200 and 600 °C in the DSC (Figure 5). The peak enthalpies were calculated from the areas under the observed peaks. The enthalpies of the peaks between 200 and 600 °C were summed and reported in Table 4. The enthalpies of commercially available MDH are listed for comparison. [Table 4]

[0141] The coprecipitated material has an enthalpy between 200 and 600°C higher than the sum of the individual components. As seen in Example 4C, the enthalpy is 1256 J / g, but the individual components are 30% La hydroxide (508 J / g) and 70% Mg oxide (669 J / g), i.e., 30% x 508 + 70% x 669 = 621 J / g.

[0142] Example 5. Additive containing co-precipitated yttrium zinc aluminum Co-precipitated yttrium zinc aluminum additive was prepared by preparing a solution containing dissolved Y(NO3)3 at a concentration of approximately 14 g yttrium oxide basis / L, dissolved Al(NO3)3 at a concentration of approximately 14 g aluminum oxide basis / L, and dissolved Zn(NO3)2 at a concentration of approximately 7 g zinc oxide basis / L. The total metal oxide concentration was 35 g / L. This solution was then added to a solution of approximately 1 M NaOH or NH4OH at pH 9.2. Additional NaOH or NH4OH was added to maintain the pH at 9.2. The precipitate was collected by filtration and washed with DI water until the aqueous solution had a conductivity of less than 30 mS / cm. Filtration continued to dehydrate the resulting cake. The precipitate was then dried at 80-200°C for 6-12 hours. This material was then ground in a jet mill.

[0143] The resulting solid was analyzed by TGA / DSC. Significant mass loss was observed between 200 and 600 °C. A significant endothermic peak was observed between 185 and 250 °C in the DSC. The peak enthalpy was calculated from the areas under the observed peaks. The area under the 227 °C peak was found to be 82.755 J / g, the area under the 304 °C peak was 19.618 J / g, and the area under the 504 °C peak was 98.745 J / g, totaling 201.118 J / g over the temperature range of 200 to 600 °C (Figure 6). The particle size was measured and found to be D50, D90, and D100, approximately 1.71 μm, 2.98 μm, and 5.23 μm, respectively. The metal oxide content was determined by measuring the loss on ignition, which was 34%, indicating a metal oxide content of 66%. The surface area, pore radius, and pore volume were measured, and the BJH surface area was found to be 64.687 m 2 / g, BET surface area is 41.96 m 2 / g, pore radius 3.595 nm, pore volume 0.127 cm 3 / g.

[0144] The solids were dried at different temperatures for 15 minutes and then their surface areas were measured. The data are listed in Table 5 and shown in Figure 7. The data show that the surface area increases with increasing temperature, peaking at around 400°C, within the target temperature range of 200-600°C. In PVC compositions, this increase in surface area allows more of the additive's components to interact with PVC degradation products, improving combustion suppression. [Table 5]

[0145] Example 6. Additive containing co-precipitated yttrium zinc magnesium Co-precipitated yttrium zinc magnesium additive was prepared by preparing a solution containing dissolved Y(NO3)3 at a concentration of approximately 14 g yttrium oxide basis / L, dissolved Zn(NO3)2 at a concentration of approximately 7 g zinc oxide basis / L, and dissolved Mg(NO3)2 at a concentration of approximately 14 g magnesium oxide basis / L. The total metal oxide concentration was 35 g / L. This solution was then added to a solution of approximately 1 M NaOH or NH4OH at pH 9.2. Additional NaOH or NH4OH was added to maintain the pH at 9.2. The precipitate was collected by filtration and washed with DI water until the aqueous conductivity was less than 30 mS / cm. Filtration was continued to dehydrate the resulting cake. The precipitate was then dried at 80-200°C for 6-12 hours. This material was then ground in a jet mill.

[0146] The resulting solid was analyzed for loss on ignition (a measure of moisture content) at 500 °C for 1 hour, resulting in a mass loss of 35.06%. The solid was analyzed by TGA / DSC. A significant mass loss was observed between 260 and 360 °C. A significant endothermic peak was observed in the DSC over the same temperature range. The peak enthalpy was calculated from the area under the observed peaks, and the area under the 341 °C peak was found to be 524.48 J / g, and the area under the 532 °C peak was found to be 150.086 J / g, totaling 674.566 J / g over the temperature range of 200 to 600 °C (Figure 6). Particle size measurements revealed D50 to be approximately 1.76 μm, D90 to be approximately 3.986 μm, and D100 to be approximately 8.01 μm. The metal oxide content was determined from the loss on ignition to be 30.6%, resulting in a metal oxide content of 69.4%.

[0147] The solids were dried at different temperatures for 15 minutes and then their surface areas were measured. The data are listed in Table 6 and shown in Figure 8. The data show that the surface area increases with increasing temperature, peaking near 400°C, within the target temperature range of 200-600°C. In PVC compositions, this increased surface area allows more of the additive's components to interact with PVC degradation products, improving combustion suppression. [Table 6]

[0148] Examples 7A-7J. Preparation of chlorinated paraffin-free polyvinyl chloride (PVC) A hopper was charged with polyvinyl chloride resin (PVC resin k70), plasticizer (DIDP diisodecyl phthalate), flame retardant (Ecopiren 3.5C (MDH) and ATO), filler (calcium carbonate Omiyacarb 2T-AV), and materials selected from Examples 1, 5, and 6, MDH, ATH, and zinc oxide, in the amounts listed in Tables 7-9. The amount of each component can be adjusted to suit the desired properties of the resulting PVC. The hopper fed these materials into a hot mixer heated to 150-165°C. After mixing for 6-10 minutes, the mixed materials were fed into an extruder. After extrusion, the materials were cooled to 110-120°C and cut into pellets. The pellets were cooled to 35-40°C and sieved using an air-cooled vibrating screen. The product was then packaged and stored. The resulting PVC compounds were tested for density, hardness, limiting oxygen index (LOI), Congo red test, smoke density, and UL94 rating. The results are shown in Tables 7-9. [Table 7]

[0149] Example 7A is PVC representing a normal ATO load. In Example 7B, two-thirds of the ATO (compared to Example 7A) was replaced with the material from Example 1, resulting in significantly increased Congo Red and significantly decreased smoke density (compared to Example 7A). Both of these are favorable and can be attributed to the presence of the material from Example 1. In Example 7C, two-thirds of the ATO (compared to Example 7A) was replaced with a mixture of MDH and zinc oxide, where the zinc oxide and MDH were in a 20:80 ratio. The results show a decrease in Congo Red (compared to Example 7A), which is unfavorable. In Example 7D, two-thirds of the ATO (compared to Example 7A) was replaced with a mixture of ATH and zinc oxide, where the zinc oxide and ATH were in a 20:80 ratio. The results show a decrease in Congo Red (compared to Example 7A), which is unfavorable. [Table 8]

[0150] In Example 7E, two-thirds of the ATO (compared to Example 7A) is replaced with the co-precipitated additive from Example 5. In Example 7F, two-thirds of the ATO (compared to Example 7A) is replaced with a mixture of the material from Example 1, ATH, and zinc oxide, with a Y:Zn:Al ratio matching that of Example 7E. The results show that the PVC composition of Example 7E has significantly improved Congo red and significantly lower smoke density than Example 7F. This indicates that the co-precipitated additive imparts more favorable flame retardancy to the PVC composition, even though Examples 7E and 7F have identical elemental compositions.

[0151] In Example 7G, two-thirds of the ATO (compared to Example 7A) is replaced with the co-precipitated additive from Example 6. In Example 7H, two-thirds of the ATO (compared to Example 7A) is replaced with a mixture of the material from Example 1, MDH, and zinc oxide, with a Y:Zn:Mg ratio matching that of Example 7G. The results show that the PVC composition of Example 7G has improved LOI and lower smoke density than Example 7H. This indicates that the co-precipitated additive imparts more favorable flame retardancy to the PVC composition, even though Examples 7G and 7H have identical elemental compositions. [Table 9]

[0152] In Example 7I, two-thirds of the ATO (compared to Example 7A) is replaced with the co-precipitated additive from Example 2C. In Example 7J, two-thirds of the ATO (compared to Example 7A) is replaced with a mixture of the material from Example 1 and zinc oxide, with a Y:Zn ratio matching that of Example 7I. The results show that the PVC composition of Example 7I has improved LOI and improved Congo Red than Example 7J. This indicates that the co-precipitated additive imparts more favorable flame retardancy to the PVC composition, even though Examples 7I and 7J have the same elemental composition.

[0153] Example 8. Preparation of polyvinyl chloride (PVC) containing chlorinated paraffins The hopper was charged with polyvinyl chloride resin (PVC resin k70), plasticizer (DIDP diisodecyl phthalate), chlorinated paraffin (Essebiochlor 45), flame retardant (ATO), filler (calcium carbonate Omiyacarb 2T-AV), zinc borate, and materials selected from Examples 1, 2, 5, and 6, MDH, ATH, and zinc oxide, in the amounts listed in Tables 10-12. The amount of each component can be adjusted to suit the desired properties of the resulting PVC. The hopper fed these materials into a hot mixer heated to 150-165°C. After mixing for 6-10 minutes, the mixed materials were fed into an extruder. After extrusion, the materials were cooled to 110-120°C and cut into pellets. The pellets were cooled to 35-40°C and sieved using an air-cooled vibrating screen. The product was then packaged and stored. The resulting PVC compounds were tested for density, hardness, limiting oxygen index (LOI), Congo Red test, and UL94 rating. The results are shown in Tables 10-12. [Table 10]

[0154] Example 8A is PVC representing normal ATO loading. In Example 8B, half of the ATO (compared to Example 8A) is replaced with the material from Example 1. The results for Example 8B show an increase in Congo Red over Example 8A. [Table 11]

[0155] In Example 8C, half of the ATO (compared to Example 8A) is replaced with the co-precipitated additive from Example 2B. In Example 8D, half of the ATO (compared to Example 8A) is replaced with a mixture of the material from Example 1 and zinc oxide, with a Y:Zn ratio matching that of Example 8C. The results show that the PVC composition of Example 8C has significantly improved Congo Red compared to Example 8D. This indicates that the co-precipitated additive imparts more favorable flame retardancy to the PVC composition, even though Examples 8C and 8D have the same elemental composition.

[0156] In Example 8E, half of the ATO (compared to Example 8A) is replaced with the co-precipitated additive from Example 2C. In Example 8F, half of the ATO (compared to Example 8A) is replaced with a mixture of the material from Example 1 and zinc oxide, with a Y:Zn ratio matching that of Example 8E. The results show that the PVC composition of Example 8E has significantly improved Congo Red compared to Example 8F. This indicates that the co-precipitated additive imparts more favorable flame retardancy to the PVC composition, even though Examples 8E and 8F have identical elemental compositions.

[0157] In Example 8G, half of the ATO (compared to Example 8A) is replaced with the co-precipitated additive from Example 2D. In Example 8H, half of the ATO (compared to Example 8A) is replaced with a mixture of the material from Example 1 and zinc oxide, with a Y:Zn ratio matching that of Example 8G. The results show that the PVC composition of Example 8G has significantly improved Congo Red compared to Example 8H. This indicates that the co-precipitated additive imparts more favorable flame retardancy to the PVC composition, even though Examples 8G and 8H have identical elemental compositions. [Table 12]

[0158] In Example 8I, half of the ATO (compared to Example 8A) is replaced with the co-precipitated additive from Example 5. In Example 8J, half of the ATO (compared to Example 8A) is replaced with a mixture of the material from Example 1, zinc oxide, and ATH, with a Y:Zn:Al ratio matching that of Example 8I. The results show that the PVC composition of Example 8I has significantly improved Congo Red compared to Example 8J. This indicates that the co-precipitated additive imparts more favorable flame retardancy to the PVC composition, even though Examples 8I and 8J have identical elemental compositions.

[0159] In Example 8K, half of the ATO (compared to Example 8A) is replaced with the co-precipitated additive from Example 6. In Example 8L, half of the ATO (compared to Example 8A) is replaced with a mixture of the material from Example 1, zinc oxide, and MDH, with a Y:Zn:Mg ratio that matches that of Example 8K. The results show that the PVC composition of Example 8K has significantly improved Congo Red compared to Example 8L. This indicates that the co-precipitated additive imparts more favorable flame retardancy to the PVC composition, even though Examples 8K and 8L have identical elemental compositions.

[0160] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and the like used in the specification and claims are understood to be modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations and may vary depending upon the desired properties sought to be obtained.

[0161] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the technology are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible, however, any numerical values ​​inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0162] It is apparent that the compositions and methods described herein are well adapted to achieve the objects and advantages mentioned, as well as the benefits inherent therein. Those skilled in the art will recognize that the methods and systems herein can be implemented in numerous ways and are therefore not limited by the illustrative embodiments and examples set forth above. In this regard, any number of features of different embodiments described herein may be combined in one embodiment, and alternative embodiments having fewer or more than all of the features described herein are possible.

[0163] While various embodiments have been described for the purposes of this disclosure, various changes and modifications may be made within the scope contemplated by this disclosure. Numerous other variations may be made that are encompassed by the spirit of this disclosure, as will be readily apparent to those skilled in the art.

Claims

1. 1. A polyvinyl chloride (PVC) composition comprising: PVC resin; an inorganic flame retardant selected from the group consisting of antimony trioxide (ATO), magnesium dihydroxide (MDH), aluminum trihydrate (ATH), and mixtures thereof; and A coprecipitated rare earth additive comprising a rare earth and one or more of zinc, aluminum, and magnesium, said coprecipitated rare earth additive containing from about 5 to about 95 weight percent rare earth measured on a rare earth oxide basis. Including, The composition is a polyvinyl chloride (PVC) composition comprising 100 phr of PVC resin and having a UL94 rating of V-2 or higher for a specimen having a thickness of about 0.8 mm.

2. 10. The PVC composition of claim 1, comprising from about 1 phr to about 10 phr of the coprecipitated rare earth additive.

3. 3. The PVC composition of claim 1 or 2, wherein the rare earth is yttrium, lanthanum, cerium, neodymium, praseodymium, or a mixture thereof.

4. 3. The PVC composition of claim 1 or 2, wherein the precipitated rare earth additive comprises: (a) yttrium, zinc, and aluminum; (b) yttrium, zinc, and magnesium; (c) yttrium and zinc; or (d) yttrium, zinc, magnesium, and aluminum.

5. 4. The PVC composition of claim 3 wherein said rare earth is yttrium.

6. 6. The PVC composition of claim 1, wherein the inorganic flame retardant is ATO, and the PVC composition contains less ATO than a PVC composition not containing the coprecipitated rare earth additive to achieve the same UL 94 rating.

7. 7. The PVC composition of claim 6, wherein the coprecipitated rare earth additive is yttrium and zinc, and the ratio of yttrium:zinc is from about 90:10 to about 10:90, and the ratio of ATO:rare earth is from about 1:3 to about 3:

1.

8. 8. The PVC composition of claim 7, wherein the ratio of ATO to coprecipitated rare earth additive is from about 1:1 to about 1:

2.

9. 8. The PVC composition of claim 7, wherein the composition comprises ATO and the coprecipitated rare earth additive in a combined amount of from about 3 phr to about 10 phr.

10. 10. The PVC composition of claim 9, wherein said composition comprises from about 1 to about 3.5 phr ATO and from about 1 to about 4.5 phr coprecipitated rare earth additive.

11. 7. The PVC composition of claim 6, wherein the coprecipitated rare earth additive is yttrium, zinc, magnesium, and contains, measured on an oxide basis, from about 5% to about 90% by weight yttrium; from about 5% to about 50% by weight zinc; and from about 5% to about 90% by weight magnesium, and the ratio of ATO:coprecipitated rare earth additive is from about 1:3 to about 3:

1.

12. 12. The PVC composition of claim 11, wherein said ratio of ATO:coprecipitated rare earth additive is from about 1:1 to about 1:

2.

13. 12. The PVC composition of claim 11, wherein the coprecipitated rare earth additive is yttrium, zinc, magnesium in a ratio of about 40:20:

40.

14. 12. The PVC composition of claim 11, wherein the composition comprises ATO and coprecipitated rare earth additive in a combined amount of from about 3 phr to about 10 phr.

15. 12. The PVC composition of claim 11, wherein the composition comprises from about 1 to about 3.5 phr ATO and from about 1 to about 4.5 phr coprecipitated rare earth additive.

16. 7. The PVC composition of claim 6, wherein the coprecipitated rare earth additive is yttrium, zinc, and aluminum, and the coprecipitated rare earth additive contains, measured on an oxide basis, from about 5% to about 90% by weight yttrium; from about 5% to about 50% by weight zinc; and from about 5% to about 90% by weight aluminum, and the ratio of ATO:coprecipitated rare earth additive is from about 1:3 to about 3:

1.

17. 17. The PVC composition of claim 16, wherein the ratio of ATO to coprecipitated rare earth additive is from about 1:1 to about 1:

2.

18. 17. The PVC composition of claim 16, wherein the coprecipitated rare earth additive is yttrium, zinc, and aluminum in a ratio of about 40:20:

40.

19. 17. The PVC composition of claim 16, wherein the composition comprises ATO and the coprecipitated rare earth additive in a combined amount of from about 3 phr to about 10 phr.

20. 17. The PVC composition of claim 16, wherein the composition comprises from about 1 to about 3.5 phr ATO and from about 1 to about 4.5 phr coprecipitated rare earth additive.

21. 21. The PVC composition of any one of claims 1 to 20, wherein the PVC composition has a UL 94 rating of V-0 or V-1 for a 0.8 mm thick specimen.

22. 22. The PVC composition of any one of claims 1 to 21, further comprising an additive selected from the group consisting of fillers, plasticizers, colorants, stabilizers, lubricants, organic flame retardants, smoke suppressants, and mixtures thereof.

23. 23. The PVC composition of any one of claims 1 to 22, wherein the PVC composition contains the components of the coprecipitating additive but exhibits improved thermal stability as measured by Congo Red at 200°C compared to the same PVC composition in which a blend of these components, rather than a coprecipitating agent, has been added to the PVC composition.

24. 24. The PVC composition of any one of claims 1 to 23, wherein the PVC composition exhibits improved LOI compared to the same PVC composition containing the components of the coprecipitating additive, but added to the PVC composition as a blend of these components rather than a coprecipitating agent.

25. 25. The PVC composition of any one of claims 1 to 24, wherein the PVC composition exhibits improved smoke density, as measured in accordance with ASTM D2843-22, compared to an identical PVC composition containing the components of the coprecipitating additive, but where these components are added to the PVC composition as a blend rather than as a coprecipitating agent.

26. 1. A PVC composition comprising: a PVC resin; ATO; and a coprecipitated rare earth additive consisting of a rare earth, zinc, and optionally aluminum, magnesium, or a mixture thereof, said coprecipitated rare earth additive containing from about 5 to about 95 weight percent rare earth measured on a rare earth oxide basis; The composition comprises 100 phr of PVC resin, and has a UL94 rating of V-0, V-1, or V-2 for a specimen having a thickness of about 0.8 mm, and the PVC composition contains less ATO than a PVC composition that does not contain the coprecipitated rare earth additive to achieve the same UL94 rating.

27. 27. The PVC composition of claim 26, further comprising an additive selected from the group consisting of fillers, plasticizers, colorants, stabilizers, lubricants, organic flame retardants, smoke suppressants, and mixtures thereof.

28. 28. The PVC composition of claim 26 or 27, wherein the PVC composition exhibits improved thermal stability as measured by Congo Red at 200°C compared to an identical PVC composition containing the components of the coprecipitating additive, but where these components are added to the PVC composition as a blend rather than as a coprecipitating agent.

29. 29. The PVC composition of any one of claims 26 to 28, wherein the PVC composition exhibits improved LOI compared to the same PVC composition containing the components of the coprecipitating additive, but added to the PVC composition as a blend of these components rather than a coprecipitating agent.

30. 30. The PVC composition of any one of claims 26 to 29, wherein the PVC composition exhibits improved smoke density, as measured in accordance with ASTM D2843-22, compared to an identical PVC composition containing the components of the coprecipitating additive, but where these components are added to the PVC composition as a blend rather than as a coprecipitating agent.

31. 27. The PVC composition of claim 1 or 26, comprising about 0 phr chlorinated paraffins.

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