How to recycle polyvinyl butyral

Abstract

A method for converting polyvinyl butyral (PVB) to its raw components (e.g., polyvinyl alcohol (PVOH) and butyraldehyde) via hydrolysis. The method facilitates hydrolysis of a PVB feed composition, which may be derived from recycled materials, into its raw components. Recycled PVOH, PVB with a high residual PVOH content, and / or butyraldehyde recovered from this process may then be used to produce purified PVB and / or recycled PVB.

Description

[Background technology]

[0001] Waste, especially non-biodegradable waste, can have a negative impact on the environment if disposed of in landfills after single use. Therefore, from an environmental perspective, it is desirable to recycle as much waste as possible. However, recycling waste can be economically challenging. To maximize recycling efficiency, large-scale production facilities are encouraged to process feedstocks containing recycled materials derived from various waste streams. Commercial facilities involved in the production of non-biodegradable products or products destined for landfills can potentially benefit greatly from using recycled feedstocks.

[0002] Polyvinyl butyral (PVB) is often used to manufacture polymer sheets that can be used as interlayers in multilayer panels containing light-transmitting laminates, such as safety glass and polymer laminates. PVB is also used in photovoltaic panels to encapsulate panels used in commercial and residential power generation and distribution. PVB waste resulting from the manufacture and / or disposal of such PVB products is generally unsuitable for recycling into other products without intermediate processing. For example, one or more of the following may be present in the PVB waste: additives, adhesives, plasticizers, etc. Such additives generally must be removed from the PVB waste in order for the PVB to be recycled.

[0003] Therefore, it is desirable to develop a process for efficiently recycling low-quality PVB or PVB waste to produce recycled-content polymeric materials. Summary of the Invention

[0004] Provided herein is a method for recycling polyvinyl butyral (PVB), which includes hydrolyzing or partially hydrolyzing raw PVB material to produce a solution containing recycled polyvinyl alcohol (r-PVOH) derived from the raw PVB material.

[0005] Also provided herein is a method for recycling polyvinyl butyral (PVB), comprising producing a plurality of PVB particles from fresh polyvinyl alcohol and fresh butyraldehyde in the presence of water, hydrolyzing a quantity of the PVB particles to produce a solution containing regenerated PVOH (r-PVOH), and producing additional PVB particles from the r-PVOH in the presence of water. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram of an exemplary process for recycling polyvinyl butyral. [Figure 2] FIG. 1 is a schematic diagram of an alternative process for recycling polyvinyl butyral. [Figure 3] FIG. 1 is a schematic diagram of an exemplary process for producing and recycling polyvinyl butyral. [Figure 4] FIG. 1 is a schematic diagram of an alternative process for producing and recycling polyvinyl butyral. [Figure 5] FIG. 1 is a schematic diagram of an exemplary process for recycling polyvinyl butyral by partial hydrolysis. [Figure 6] FIG. 1 is a schematic diagram of an alternative process for recycling polyvinyl butyral by partial hydrolysis. [Figure 7] FIG. 1 is a schematic diagram of an alternative process for recycling polyvinyl butyral by partial hydrolysis. [Figure 8] FIG. 1 is a schematic diagram of an exemplary process for producing and recycling polyvinyl butyral by partial hydrolysis. [Figure 9] FIG. 1 is a schematic diagram of an exemplary process for producing and recycling polyvinyl butyral by partial hydrolysis. [Figure 10] FIG. 1 is a schematic diagram of an exemplary process for producing and recycling polyvinyl butyral by partial hydrolysis. [Figure 11]FIG. 1 is a schematic diagram of an exemplary process for recycling polyvinyl butyral using an alcohol-based aldehyde scavenger. [Figure 12] FIG. 1 is a schematic diagram of an alternative process for recycling polyvinyl butyral using an alcohol-based aldehyde scavenger. [Figure 13] FIG. 1 is a schematic diagram of an exemplary process for recycling polyvinyl butyral using an amine-based aldehyde scavenger. [Figure 14] FIG. 1 is a schematic diagram of an alternative process for recycling polyvinyl butyral using an amine-based aldehyde scavenger. [Figure 15] FIG. 1 is a schematic diagram of an exemplary process for recycling polyvinyl butyral via hydrogenation. DETAILED DESCRIPTION OF THE INVENTION

[0007] Also provided herein is a method for recycling polyvinyl butyral (PVB). The method includes partially hydrolyzing raw PVB to produce a reaction product containing unreacted PVB and butyraldehyde, where the unreacted PVB comprises residual polyvinyl alcohol (PVOH). The method also includes reacting the residual PVOH with additional butyraldehyde to produce regenerated PVB.

[0008] Also provided herein is a method for recycling polyvinyl butyral (PVB), the method including: forming a plurality of PVB particles from fresh polyvinyl alcohol (PVOH) and fresh butyraldehyde in the presence of water; partially hydrolyzing a quantity of the PVB particles to form a reaction product comprising unreacted PVB and butyraldehyde, wherein the unreacted PVB comprises residual PVOH; and reacting the residual PVOH with additional butyraldehyde to form regenerated PVB.

[0009] Provided herein is a method for recycling polyvinyl butyral (PVB), which includes hydrolyzing raw PVB in the presence of hydrogen and a hydrogenation catalyst to produce a solution containing recycled polyvinyl alcohol (PVOH) and recycled butanol.

[0010] Also provided herein is a method for recycling polyvinyl butyral (PVB), comprising: producing a plurality of PVB particles from fresh polyvinyl alcohol (PVOH) and fresh butyraldehyde in the presence of water; hydrolyzing a quantity of the PVB particles in the presence of at least one amino-functional compound to produce a solution containing regenerated PVOH and regenerated butanol; and producing additional PVB particles from the regenerated PVOH in the presence of water.

[0011] Provided herein is a method for recycling polyvinyl butyral (PVB) by hydrolyzing raw PVB in the presence of an aldehyde scavenger to produce a solution containing recycled polyvinyl alcohol (PVOH) and recycled acetal.

[0012] Also provided herein is a method for recycling polyvinyl butyral (PVB), comprising producing a plurality of PVB particles from fresh polyvinyl alcohol and fresh butyraldehyde in the presence of water, hydrolyzing a quantity of the PVB particles in the presence of an aldehyde scavenger to produce a solution containing regenerated PVOH, and producing additional PVB particles from the regenerated PVOH in the presence of water.

[0013] Provided herein is a method for recycling polyvinyl butyral (PVB), which comprises hydrolyzing raw PVB in the presence of at least one amino-functional compound to produce a solution comprising recycled polyvinyl alcohol (PVOH) and one or more butylimine derivatives.

[0014] Also provided herein is a method for recycling polyvinyl butyral (PVB), comprising producing a plurality of PVB particles from fresh polyvinyl alcohol and fresh butyraldehyde in the presence of water, hydrolyzing a quantity of the PVB particles in the presence of at least one amino-functional compound to produce a solution containing regenerated PVOH and one or more butylimine derivatives, and producing additional PVB particles from the regenerated PVOH in the presence of water.

[0015] The following will be embodied:

[0016] E1. A method for recycling polyvinyl butyral (PVB), comprising hydrolyzing or partially hydrolyzing a PVB raw material to produce a solution comprising regenerated polyvinyl alcohol (PVOH) derived from the PVB raw material.

[0017] E2. The method of embodiment E1, wherein said hydrolysis or partial hydrolysis does not occur in the presence of a catalyst.

[0018] E3. The method of embodiment E2, wherein the hydrolysis or partial hydrolysis does not occur in the presence of a catalyst and is carried out at a temperature within the range of about 150°C to about 250°C.

[0019] E4. The method of embodiment E1, wherein said hydrolysis or partial hydrolysis occurs in the presence of an acid catalyst.

[0020] E5. The method of embodiment E4, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0021] E6 The method of embodiment E4, wherein the hydrolysis or partial hydrolysis is carried out in the presence of an acid catalyst and a cocatalyst that forms an unstable hydrolyzable molecule, such as an amine, alcohol, or aminoalcohol, as described elsewhere herein.

[0022] E7. The method of any one of embodiments E5 or E6, wherein the hydrolysis or partial hydrolysis is carried out in the presence of an acid catalyst and at a temperature within the range of from about 70°C to about 150°C.

[0023] E8. The method of any one of embodiments A1-E7, wherein the PVB feedstock is hydrolyzed to PVOH at a conversion of at least 90%.

[0024] E9. The method of any one of embodiments A1-E7, wherein the PVB feedstock is partially hydrolyzed to a conversion of less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, between 20% and 90%, between 30% and 90%, between 40% and 90%, between 50% and 90%, between 50% and 80%, or between 50% and 70%.

[0025] E10. The method of any of embodiments E1-E7 and 9, wherein the partial hydrolysis of the PVB raw material results in a slurry comprising between 25% and 75% by weight, between 30% and 70% by weight, between 35% and 65% by weight, or between 40% and 60% by weight of water-insoluble PVB.

[0026] E11. The method of any of embodiments E1-E7 and 9, wherein the partial hydrolysis of the PVB feedstock produces a slurry containing more than 25 wt%, more than 50 wt%, more than 75 wt%, between 25 wt% and 75 wt%, between 30 wt% and 70 wt%, between 35 wt% and 65 wt%, or between 40 wt% and 60 wt% water.

[0027] E12. The method of any one of embodiments E1-E11, further comprising cooling the recycled PVOH prior to the reacting step.

[0028] E13. The method of any of embodiments E1-E12, further comprising centrifuging the solution to remove one or more insoluble components from the solution prior to the filtering step.

[0029] E14. The method of any one of embodiments E1-E13, wherein the PVB feedstock is derived from at least one of post-industrial recycled or post-consumer recycled materials.

[0030] E15. PVB raw material is at least 8%, at least 9%, at least 9.5%, at least 10%, at least 10.5%, at least 11%, at least 11.5%, at least 12%, at least 12.5%, at least 13%, at least 13.5%, at least 14%, at least 14.5%, at least 15%, at least 15.5%, at least 16%, at least 16.5%, at least 17%, at least 17.5%, at least 18%, at least 18.5%, at least 19%, at least 20%. The method of any of embodiments E1-E14, having a residual PVOH content of 5, at least 20, at least 25, at least 26, at least 30, at least 32%, at least 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, and / or no more than 100%, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 35% or less, 32% or less, 30% or less, 25% or less, 22% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, or 8% or less.

[0031] E16. The method of any one of embodiments E1-E15, wherein the PVB feedstock comprises two or more PVB resins having different compositions from one another.

[0032] E17. The method of any one of embodiments E1-E16, wherein the PVB feedstock comprises two or more PVB resins having different residual PVOH contents from one another.

[0033] E18. The method of any one of embodiments E1-E17, wherein the PVB stock comprises at least 1, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, or at least 90 phr, and / or no more than 100, no more than 90, no more than 85, no more than 80, no more than 75, no more than 70, no more than 65, no more than 60, no more than 55, no more than 50, no more than 45, no more than 40, no more than 35, no more than 30, no more than 25, no more than 20, no more than 15, or no more than 10 phr of plasticizer, based on the total weight of the PVB stock.

[0034] E19. The method of any one of embodiments E1-E18, further comprising extracting a plasticizer from the PVB raw material.

[0035] E20. The method of any one of embodiments E1-E19, further comprising, prior to the hydrolysis step, sizing the PVB feedstock to an average particle size of less than about 400 microns, 350 microns, 300 microns, or 250 microns, or between about 200 microns and about 400 microns, between about 225 microns and about 375 microns, or between about 250 microns and about 350 microns.

[0036] E21. The method of any of embodiments E1-E20, further comprising reacting the residual PVOH with butyraldehyde to produce recycled PVB having a residual PVOH content of between 1% and 90%, between 5% and no more than 30%, between 7% and 30%, or between 16% and 20%.

[0037] E22. The method of any of embodiments E1-E21, further comprising reacting the residual PVOH with butyraldehyde to produce recycled PVB having a target residual PVOH content, wherein the PVB feedstock has a residual PVOH content that is 1% greater, 2% greater, 3% greater, 4% greater, 5% greater, or 10% greater than the target residual PVOH content.

[0038] E23. The method of any of embodiments E1-E22, further comprising recovering butyraldehyde produced in said hydrolysis step.

[0039] E24. The method of any one of embodiments E1-E23, further comprising reacting the residual PVOH with butyraldehyde recovered from the hydrolysis step to produce regenerated PVB.

[0040] This application generally relates to a method for converting polyvinyl butyral (PVB) into its raw components (e.g., polyvinyl alcohol (PVOH) and butyraldehyde) via hydrolysis, as well as a method for producing purified PVB from recovered PVOH and / or butyraldehyde. Generally, PVOH and butyraldehyde are starting materials in the PVB polymerization reaction. The methods described herein facilitate reversing the polymerization reaction by hydrolyzing, or "deacetalizing," the PVB feed composition into its raw components. The recycled PVOH and / or butyraldehyde recovered from this process can then be used to produce purified PVB and / or recycled PVB. When the PVB being converted via hydrolysis is waste PVB (e.g., off-spec PVB, scrap PVB, and / or post-consumer PVB), the recycled material (e.g., r-PVOH, r-butyraldehyde, and r-PVB) generated from the waste PVB can comprise recycled material derived from the waste PVB.

[0041] The PVB feed composition may be derived from post-consumer recycled PVB, non-standard industrial PVB, and / or industrial scrap PVB, where the non-standard industrial PVB may be produced during the normal course of PVB resin manufacturing, and the scrap industrial PVB may be produced during the normal course of PVB interlayer manufacturing. For example, some PVB produced from the polymerization of PVOH and butyraldehyde may be unusable (i.e., non-standard), even if the polymerization is carried out under optimal or near-optimal conditions. Additionally, scrap PVB may be produced during the extrusion of a PVB-containing interlayer, for example, by trimming the edges of a PVB sheet.

[0042] Thus, the methods described herein facilitate the reduction of non-biodegradable waste, such as waste PVB, and facilitate the production of purified PVB from such waste and / or from unusable PVB. That is, the methods described herein provide for the regeneration of polymer products similar to PVB polymerization products from new raw material components with comparable product quality and minimal environmental impact.

[0043] For example, the methods described herein may include the steps of: (a) sizing a PVB feed composition; (b) optionally dissolving the sized-reduced PVB in a solvent; (c) hydrolyzing the PVB to form a PVOH solution; (d) recovering reclaimed PVOH from the solution; (e) producing reclaimed PVB from the reclaimed PVOH; (f) inspecting the reclaimed PVB for defects; (g) hydrolyzing the off-specification PVB to produce additional PVOH; and (h) producing additional reclaimed PVB from the additional PVOH.

[0044] The methods described herein may include the steps of (a) producing PVB from fresh PVOH and butyraldehyde; (b) inspecting the produced PVB for defects; (c) optionally sizing the off-spec PVB; (d) hydrolyzing the off-spec PVB to produce reclaimed PVOH; and (e) producing additional PVB from the reclaimed PVOH.

[0045] Systems and equipment for practicing these methods, as well as their details and features, may vary. Non-limiting examples of systems, equipment, and / or processes for use in practicing embodiments of the present disclosure are shown in Figures 1-4.

[0046] 1 and 2, chemical recycling facility 100 is designed to process PVB feedstock 102 to produce purified PVB and / or reclaimed PVB, as described above. In some embodiments, PVB feedstock 102 is derived from a chemical recycling feedstock that includes one or more PVB feed compositions from a raw material supply. As used herein, the term "PVB feed composition" refers to post-consumer, scrap, and / or discarded PVB feed composition, such as discarded PVB that would typically be sent to a landfill.

[0047] The PVB raw material 102 may include an unprocessed or partially processed PVB feed composition. As used herein, the term "unprocessed PVB feed composition" refers to a PVB feed composition that has not been subjected to any automated or mechanized sorting, cleaning, or crushing. A partially processed PVB feed composition may be sourced, for example, from a reclaimer. In one embodiment, or in combination with any embodiment referred to herein, the PVB raw material 102 may include a post-industrial recycled PVB feed composition and / or a post-consumer recycled PVB feed composition.

[0048] In one embodiment, or in combination with any embodiment mentioned herein, all or a portion of the PVB raw material 102 may come from a recycling facility that recovers glass from waste and scrap glass laminates containing PVB interlayers.

[0049] As used herein, the term "chemically recycled feedstock" refers to all feedstocks supplied to chemical recycling facility 100 and encompasses all feedstock streams introduced therein.

[0050] The chemical recycling facility 100 may include a feed system for introducing chemical recycling feedstocks, including PVB feedstocks 102, such as solid PVB resin, into the facility. The feed system can be any conventional feed system for handling solid particulate feedstocks, such as a screw feeder or a belt conveying system.

[0051] In one embodiment, or in combination with any embodiment mentioned herein, the chemical recycled feedstock may comprise at least 25%, at least 50%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% by weight of at least one, two, three, four, five, or six PVB feed compositions, based on the total weight of the feedstream. Additionally, or alternatively, the chemical recycled feedstock may comprise less than 99%, less than 95%, less than 90%, less than 85%, less than 80%, less than 75%, or less than 70% by weight of at least one, two, three, four, five, or six PVB feed compositions, based on the total weight of the feedstream.

[0052] In one embodiment, or in combination with any embodiment mentioned herein, the chemical recycling feedstock supplied to the chemical recycling facility consists essentially of, or consists of, at least 1, 2, 3, 4, 5, or 6 PVB feed compositions.

[0053] In one embodiment, or in combination with any embodiment mentioned herein, the chemical recycling feedstock supplied to the chemical recycling facility consists essentially of, or consists of, a single PVB feed composition.

[0054] In one embodiment, or in combination with any embodiment mentioned herein, the chemically recycled feedstock comprises less than 10 wt%, less than 5 wt%, less than 2 wt%, less than 1 wt%, less than 0.5 wt%, or less than 0.1 wt%, of halogenated plastics such as polyvinyl chloride, based on the total weight of the feedstream.

[0055] In one embodiment, or in combination with any embodiment mentioned herein, the chemically recycled feedstock comprises less than 10 wt%, less than 5 wt%, less than 2 wt%, less than 1 wt%, less than 0.5 wt%, or less than 0.1 wt% polyolefins (e.g., polypropylene and / or polyethylene) and / or polyesters (e.g., polyethylene terephthalate) based on the total weight of the feedstream.

[0056] In one embodiment, or in combination with any of the mentioned embodiments, the chemically recycled feedstock comprises 20% or less, 15% or less, 12% or less, 10% or less, 8% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, or 1% or less by weight of biowaste, based on the total weight of the feedstock stream. As used herein, the term "biowaste" refers to materials derived from living organisms. Exemplary biowastes include, but are not limited to, cotton, wood, sawdust, food scraps, animals and animal parts, plants and plant parts, and manure.

[0057] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feedstock 102 may include one or more thermoplastic polymers in addition to or in place of PVB. Examples of suitable thermoplastic polymers may include, but are not limited to, poly(vinyl acetal) resin, polyurethane (PU), poly(ethylene-co-vinyl acetate) (EVA), polyvinyl chloride (PVC), poly(vinyl chloride-co-methacrylate), polyethylene, polyolefin, ethylene-acrylic acid ester copolymer, poly(ethylene-co-butyl acrylate), silicone elastomer, epoxy resin, acid copolymer (e.g., ethylene / carboxylic acid copolymer and its ionomer), or combinations thereof.

[0058] When the PVB feed composition described herein includes a PVB resin, the PVB resin can be formed according to any suitable method. The PVB resin can be formed by acetalization of polyvinyl alcohol with one or more aldehydes, optionally in the presence of an acid catalyst. The resulting resin can then be isolated, stabilized, and dried according to known methods, such as those described in U.S. Pat. Nos. 2,282,057 and 2,282,026, and Wade, B. 2016, Vinyl Acetal Polymers, Encyclopedia of Polymer Science and Technology. 1-22 (online, copyright 2016 John Wiley & Sons, Inc.), the disclosures of which are incorporated herein by reference in their entireties. The resulting PVB resin may have a total acetalization percentage of at least 50%, at least 60%, at least 70%, at least 75%, at least 80%, at least 85%, or at least 90% by weight, as measured according to ASTM D-1396, unless otherwise specified. The total amount of aldehyde residues in the PVB resin can be collectively referred to as the acetal component, with the remainder of the PVB resin being residual vinyl alcohol (hydroxyl) groups and residual acetate groups, which are discussed in more detail below.

[0059] In one embodiment, or in combination with any embodiment mentioned herein, the PVB resin in the PVB raw material 102 can be a poly(vinyl n-butyral) resin containing primarily residues of butanal, and may, for example, contain no more than 50% by weight, no more than 40% by weight, no more than 30% by weight, no more than 20% by weight, no more than 10% by weight, no more than 5% by weight, or no more than about 2% by weight of residues of aldehydes other than butanal, based on the total weight of all aldehyde residues in the resin.

[0060] In one embodiment, or in combination with any embodiment described herein, the molecular weight of the PVB resin in the PVB raw material 102 can be at least 50,000, at least 70,000, or at least 100,000 daltons, and / or no more than 800,000, 550,000, 500,000, 450,000, 425,000, or 300,000 daltons, as measured by size exclusion chromatography using low-angle laser light scattering (SEC / LALLS) techniques according to Cotts and Ouano. As used herein, the term "molecular weight" refers to weight-average molecular weight (Mw). The molecular weight of the PVB resin can range from about 50,000 to about 600,000, from about 70,000 to about 450,000, or from about 100,000 to about 425,000 daltons.

[0061] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feedstock 102 may comprise at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 25 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 85 wt%, at least 90 wt%, at least 95 wt%, or at least 98 wt% of the PVB feed composition, based on the total weight of the PVB feed composition.

[0062] In one embodiment, or in combination with any embodiment mentioned herein, the chemical recycled feedstock may include at least two different PVB feed compositions, including at least a first PVB feed composition and a second PVB feed composition, where the first PVB feed composition has a different PVB content relative to the second PVB feed composition. For example, the difference between the PVB content of the first and second PVB feed compositions may be at least 2 wt%, at least 5 wt%, at least 10 wt%, at least 12 wt%, at least 15 wt%, at least 20 wt%, or at least 30 wt%. As used herein, the terms "weight percent difference" or "difference of at least weight percent" refer to the difference between two given weight percents calculated by subtracting one number from the other.

[0063] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition may include two or more PVB resins having different compositions. For example, in some embodiments, one or both of the outer skin layers of the intermediate layer forming the PVB feed composition may be formed from a first PVB resin, while the core or inner layer may be formed from a second PVB resin. In such embodiments, the first PVB resin used to form the outer layer may have a residual polyvinyl alcohol content and / or residual acetate content that is at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, or at least 8% by weight greater or less than the residual polyvinyl alcohol content and / or residual acetate content of the second PVB resin used to form the inner layer.

[0064] As used herein, the terms "residual polyvinyl alcohol content" and "residual acetate content" refer to the amount of hydroxyl and acetate groups, respectively, remaining on the resin after processing is complete. For example, polyvinyl n-butyral can be produced by hydrolyzing polyvinyl acetate to polyvinyl alcohol and then acetalizing this polyvinyl alcohol ("PVOH") with butanal to form polyvinyl n-butyral. During the hydrolysis of polyvinyl acetate, not all acetate groups are converted to hydroxyl groups, leaving residual acetate groups on the resin. Similarly, during the acetalization of polyvinyl alcohol, not all hydroxyl groups are converted to acetal groups, again leaving residual hydroxyl groups on the resin. As a result, most poly(vinyl acetal) resins contain both residual PVOH groups (as vinyl hydroxyl groups) and residual acetate groups (as vinyl acetate groups) as part of the polymer chain. Residual PVOH content and residual acetate content are expressed as weight percent based on the weight of polymer resin, unless otherwise specified, and are measured in accordance with ASTM D-1396.

[0065] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition is at least 8%, at least 9%, at least 9.5%, at least 10%, at least 10.5%, at least 11%, at least 11.5%, at least 12%, at least 12.5%, at least 13%, at least 13.5%, at least 14%, at least 14.5%, at least 15%, at least 15.5%, at least 16%, at least 16.5%, at least 17%, at least 17.5%, at least 18%, at least 18.5%, at least 19%, at least 19.5%, at least 20%, at least 21%, at least 22%, at least 23%, at least 24%, at least 25%, at least 26%, at least 27%, at least 28%, at least 29%, at least 30%, at least 31%, at least 32%, at least 33%, at least 34%, at least 35%, at least 36%, at least 37%, at least 38%, at least 39%, at least 40%, at least 41%, at least 42%, at least 43%, at least 44%, at least 45%, at least 46%, at least 47%, at least 48%, at least 49%, at least 50%, at least 51%, at least 52%, at least 53%, at least 54%, at least 55%, at least 56%, at least 57%, at least 58%, at least 59%, at least 60%, at least 61%, at least 62%, at least 63%, at least 64%, at least 65%, at least 66%, at least 67%, at least 68%, at least 69%, at least 70%, at least 71%, at least 72%, at least 73%, at least 74%, at least 7 The polyvinyl alcohol (PVOH) content may be at least 25%, at least 26%, at least 30%, at least 32%, at least 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% and / or 100% or less, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 35% or less, 32% or less, 30% or less, 25% or less, 22% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, or 8% or less. For example, the PVB feed composition may comprise a residual polyvinyl alcohol (PVOH) content ranging from about 14 to about 45 wt%, from about 16 to about 30 wt%, from about 18 to about 25 wt%, from about 18.5 to about 20 wt%, or from about 19.5 to about 21 wt%.

[0066] In one embodiment, or in combination with any embodiment mentioned herein, the chemical recycle feedstock may include at least two different PVB feed compositions, including at least a first PVB feed composition and a second PVB feed composition, where the first PVB feed composition has a different residual PVOH content relative to the second PVB feed composition. For example, the difference between the residual PVOH content of the first and second PVB feed compositions may be at least 2 wt%, at least 5 wt%, at least 10 wt%, at least 12 wt%, at least 15 wt%, at least 20 wt%, or at least 30 wt%.

[0067] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition may comprise a residual acetate content of at least 5 wt%, at least 8 wt%, at least 10 wt%, at least 12 wt%, at least 14 wt%, at least 16 wt%, at least 18 wt%, at least 20 wt%, or at least 30 wt%, and / or less than 90 wt%, less than 80 wt%, less than 70 wt%, or less than 60 wt%.

[0068] In one embodiment, or in combination with any embodiment described herein, the chemical recycled feedstock may include at least two different PVB feed compositions, including at least a first PVB feed composition and a second PVB feed composition, where the first PVB feed composition has a different residual acetate content relative to the second PVB feed composition. For example, the difference in residual acetate content between the first and second PVB feed compositions may be at least 2 wt%, at least 5 wt%, at least 10 wt%, at least 12 wt%, at least 15 wt%, at least 20 wt%, or at least 30 wt%, and / or no more than 15 wt%, no more than 13 wt%, no more than 11 wt%, no more than 9 wt%, no more than 8 wt%, no more than 6 wt%, no more than 5 wt%, no more than 4 wt%, no more than 3 wt%, no more than 2 wt%, no more than 1 wt%, or no more than 0.5 wt%.

[0069] In one embodiment, or in combination with any embodiment referred to herein, the chemical recycled feedstock may include one or more PVB feed compositions having a residual PVOH content that is 1% greater, 2% greater, 3% greater, 4% greater, 5% greater, or 10% greater than the target residual PVOH content of the recycled PVB produced as described herein.

[0070] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition may include at least one plasticizer. For example, the PVB feed composition may include at least 1 phr, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, or at least 90 phr and / or 100 phr or less, 90 or less, 85 or less, 80 or less, 75 or less, 70 or less, 65 or less, 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, 30 or less, 25 or less, 20 or less, 15 or less, 10 or less, 5 or less, 4 or less, 3 or less, 2 or less, 1 or less, 0.5 or less, or 0.1 phr or less of at least one plasticizer. As used herein, the term "parts per hundred parts of resin" or "phr" refers to the amount of plasticizer present relative to 100 parts of resin on a weight basis.

[0071] In one embodiment, or in combination with any embodiment described herein, the chemical recycled feedstock may include at least two different PVB feed compositions, including at least a first PVB feed composition and a second PVB feed composition, where the first PVB feed composition has a different plasticizer content relative to the second PVB feed composition. For example, the difference in plasticizer content between the first and second PVB feed compositions may be at least 2 phr, at least 5 phr, at least 10 phr, at least 12 phr, at least 15 phr, at least 20 phr, or at least 30 phr, and / or no more than 15 phr, no more than 13 phr, no more than 11 phr, no more than 9 phr, no more than 8 phr, no more than 6 phr, no more than 5 phr, no more than 4 phr, no more than 3 phr, no more than 2 phr, no more than 1 phr, no more than 1 phr, no more than 0.5 phr, or no more than 0.1 phr.

[0072] In one embodiment, or in combination with any embodiment referred to herein, the plasticizer includes triethylene glycol bis(2-ethylhexanoate) (“TEG-EH”), triethylene glycol di-2-ethylbutyrate, triethylene glycol diheptanoate, tetraethylene glycol diheptanoate, tetraethylene glycol di-(2-ethylhexanoate) (“4GEH”), dioctyl adipate, hexylcyclohexyl adipate, diisononyl adipate, heptylnonyl adipate, di(butoxyethyl) adipate, dihexyl adipate, dibutyl sebacate, triethylene glycol bis(2-ethylhexanoate) (“TEG-EH”), triethylene glycol di-2-ethylbutyrate, triethylene glycol diheptanoate, tetraethylene glycol di-(2-ethylhexanoate) (“4GEH”), dioctyl adipate, hexylcyclohexyl adipate, diisononyl adipate, heptylnonyl adipate, di(butoxyethyl) adipate, dihexyl adipate, dibutyl sebacate, triethylene glycol bis(2-ethylhexanoate) (“TEG-EH”), tetraethylene glycol di-(2-ethylhexanoate) (“4GE ... di-(2-ethylhexanoate) (“3GEH”) dioctyl sebacate, bis(methoxyethyl) terephthalate, bis(butoxyethyl) terephthalate, bis(butoxyethoxyethyl) terephthalate, bis(ethoxyethyl) terephthalate, bis(ethoxyethoxyethyl) terephthalate, bis(2-ethylhexyloxyethyl) terephthalate, bis-(2-ethylhexyl) isophthalate, ethoxyethoxyethyl benzoate, butoxyethoxyethyl benzoate, butoxyethoxyethoxyethyl benzoate, dipropylene glycol di-o-toluate, or a combination of two or more thereof.

[0073] In one embodiment, or in combination with any embodiment mentioned herein, the chemical recycle feedstock may include at least two different PVB feed compositions, including at least a first PVB feed composition and a second PVB feed composition, wherein the first PVB feed composition has a different plasticizer relative to the second PVB feed composition, or the first PVB feed composition and the second PVB feed composition may have the same plasticizer.

[0074] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition may include less than 10 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, less than 1 wt%, or less than 0.5 wt%, of glass, frit, UV stabilizer, pigment, adhesion control agent, antioxidant, rubber, silicate, or a combination of two or more thereof, based on the total weight of the PVB feed composition.

[0075] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition may include at least 0.01 wt.%, at least 0.1 wt.%, or at least 0.5 wt.%, and / or less than 10 wt.%, less than 5 wt.%, less than 4 wt.%, less than 3 wt.%, less than 2 wt.%, or less than 1 wt.%, glass, based on the total weight of the PVB feed composition.

[0076] Generally, the amount of solid contaminants in a PVB feed composition can be measured by an alcohol solubility test, in which the PVB resin and plasticizer dissolve in a specified alcohol, while the solid contaminants do not. In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition may include at least 0.01 wt.%, at least 0.1 wt.%, at least 0.2 wt.%, at least 0.3 wt.%, at least 0.4 wt.%, at least 0.5 wt.%, at least 1 wt.%, at least 1.5 wt.%, at least 2 wt.%, at least 2.5 wt.%, at least 3 wt.%, at least 3.5 wt.%, at least 4 wt.%, at least 4.5 wt.%, or at least 5 wt.%, based on the total weight of the PVB feed composition, of one or more insoluble components that are not soluble in alcohol. Additionally or alternatively, the PVB feed composition may contain less than 50%, 40%, 30%, 25%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1% by weight of one or more insoluble components that are not soluble in alcohol, based on the total weight of the PVB feed composition. Typically, the alcohol can be ethanol.

[0077] In one embodiment or in combination with any embodiment mentioned herein, the insoluble component is insoluble in ethanol and may include glass, metal, polymer, salt, silicate, calcium, calcium derivatives, sodium derivatives, or combinations thereof.

[0078] Generally, in one or more embodiments, the insoluble component may include at least one polymer, such as a polyolefin, a polyester, a rubber, a polyamide, a polystyrene, or a combination of two or more thereof. In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition may include at least 0.01 wt.%, at least 0.1 wt.%, at least 0.2 wt.%, at least 0.3 wt.%, at least 0.4 wt.%, at least 0.5 wt.%, at least 1 wt.%, at least 1.5 wt.%, at least 2 wt.%, at least 2.5 wt.%, at least 3 wt.%, at least 3.5 wt.%, at least 4 wt.%, at least 4.5 wt.%, or at least 5 wt.% of at least one insoluble polymer. Additionally or alternatively, the PVB feed composition may comprise less than 50%, 40%, 30%, 25%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1% by weight of at least one insoluble polymer. The polymer that is insoluble in alcohol (e.g., ethanol) may be derived from packaging materials, recycled windshields, and / or mounting materials.

[0079] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition can include at least 0.01%, at least 0.1%, at least 0.2%, at least 0.3%, at least 0.4%, at least 0.5%, at least 1%, at least 1.5%, at least 2%, at least 2.5%, at least 3%, at least 3.5%, at least 4%, at least 4.5%, or at least 5% by weight of rubber. Additionally, or alternatively, the PVB feed composition can include less than 50%, less than 40%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1% by weight of rubber.

[0080] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition may include at least 0.01 wt.%, at least 0.1 wt.%, at least 0.2 wt.%, at least 0.3 wt.%, at least 0.4 wt.%, at least 0.5 wt.%, at least 1 wt.%, at least 1.5 wt.%, at least 2 wt.%, at least 2.5 wt.%, at least 3 wt.%, at least 3.5 wt.%, at least 4 wt.%, at least 4.5 wt.%, or at least 5 wt.% of glass, metal, salt, silicate, calcium, calcium derivatives, sodium derivatives, or combinations thereof. Additionally or alternatively, the PVB feed composition may comprise less than 50% by weight, less than 40% by weight, less than 30% by weight, less than 25% by weight, less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 9% by weight, less than 8% by weight, less than 7% by weight, less than 6% by weight, less than 5% by weight, less than 4% by weight, less than 3% by weight, less than 2% by weight, or less than 1% by weight of glass, metal, salt, silicate, calcium, calcium derivatives, sodium derivatives, or combinations thereof.

[0081] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition may include less than 10 wt.%, less than 5 wt.%, less than 4 wt.%, less than 3 wt.%, less than 2 wt.%, or less than 1 wt.% glass, based on the total weight of the PVB feed composition.

[0082] The amount of insoluble components in the PVB feed composition may be measured by mixing 20 grams of the PVB feed composition with 200 mL of 190-proof ethanol in a stirred vessel and stirring the mixture for 4 hours. The resulting solution is then sieved through a strainer (12-30 mesh) and centrifuged at 4,200 rpm for 20 minutes. The supernatant is then poured into an aluminum tray and evaporated to dryness in a fume hood until no further weight loss is detected. The material is then further dried in a 50°C oven for 2 hours, after which it is pressed into a 760-micron-thick sheet. The resulting sheet and precipitate are analyzed using a Bomem FT-NIR analyzer.

[0083] Additionally or alternatively, the amount of solid contaminants may also be measured by determining the ash content of the PVB feed composition by ASTM D5630-13.

[0084] In one embodiment, or in combination with any embodiment mentioned herein, the PVB feed composition may comprise at least 0.01 wt.%, at least 0.1 wt.%, at least 0.2 wt.%, at least 0.3 wt.%, at least 0.4 wt.%, at least 0.5 wt.%, at least 1 wt.%, at least 1.5 wt.%, at least 2 wt.%, at least 2.5 wt.%, at least 3 wt.%, at least 3.5 wt.%, at least 4 wt.%, at least 4.5 wt.%, or at least 5 wt.% ash, based on the total weight of the PVB feed composition, as measured according to ASTM D5630-13. Additionally or alternatively, the PVB feed composition may contain less than 50% by weight, less than 40% by weight, less than 30% by weight, less than 25% by weight, less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 9% by weight, less than 8% by weight, less than 7% by weight, less than 6% by weight, less than 5% by weight, less than 4% by weight, less than 3% by weight, less than 2% by weight, less than 1% by weight, or less than 0.5% by weight ash, as measured according to ASTM D5630-13, based on the total weight of the PVB feed composition.

[0085] Examples of PVB feed compositions suitable for use in the chemical recycling facilities described herein can include, but are not limited to, post-industrial or post-consumer recycled materials such as post-industrial PVB feed scrap and / or post-consumer PVB feed scrap. Exemplary post-industrial PVB feed compositions can include, for example, PVB scrap, broken laminated glass, off-grade PVB resin, oversized material from PVB manufacturing, or a combination of two or more thereof.

[0086] Particular embodiments of the PVB feed composition (in the form of an interlayer) are described in detail in PCT Patent Application Publication No. WO2021 / 127206 and U.S. Patent Application Publication No. 2017 / 0285339, the entireties of which are incorporated by reference herein to the extent not inconsistent with the present disclosure.

[0087] In general, the formulation of a PVB feed composition may vary over time depending on the source of the PVB feed composition. For example, the amount of PVB resin, plasticizer, and / or solid contaminants (e.g., glass, rubber, etc.) may vary from PVB feed composition to PVB feed composition introduced into a chemical recycling facility.

[0088] In one embodiment, or in combination with any embodiment mentioned herein, one or more of the following criteria may be applied to the PVB feed composition introduced into the chemical recycling facility 100: (i) the amount of PVB resin in the PVB feed composition changes by at least 2 wt % over time, (ii) the amount of plasticizer in the PVB feed composition changes by at least 2 phr over time, (iii) the amount of solid contaminants in the PVB feed composition changes by at least 2 wt % over time, or (iv) the ratio of PVB resin to plasticizer changes by at least 2 wt % over time. Often, at least two, at least three, or all four of the criteria are met. This may be due to variations in the source from which the PVB feed composition is derived.

[0089] As noted above, the composition of the PVB feed composition supplied to a chemical recycling facility may vary depending on its source, however, chemical recycling facilities may be designed to facilitate this variation in PVB feed composition.

[0090] In one embodiment, or in combination with any embodiment mentioned herein, the amount of PVB resin in the PVB feed composition varies by at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, at least 10%, at least 11%, at least 12%, at least 13%, at least 14%, or at least 15%, and / or less than 25% by weight over a period of 1 hour, 6 hours, 12 hours, 18 hours, 1 day, 2 days, 3 days, 4 days, or 1 week. As above, this difference can be calculated based on the difference in two given weight percentages over a specified period of time, calculated by subtracting one number from the other.

[0091] In one embodiment, or in combination with any embodiment mentioned herein, the amount of plasticizer in the PVB feed composition varies by at least 2 phr, at least 3 phr, at least 4 phr, at least 5 phr, at least 6 phr, at least 7 phr, at least 8 phr, at least 9 phr, at least 10 phr, at least 11 phr, at least 12 phr, at least 13 phr, at least 14 phr, or at least 15 phr, and / or less than 25 phr over a period of 1 hour, 6 hours, 12 hours, 18 hours, 1 day, 2 days, 3 days, 4 days, or 1 week. As above, this difference can be calculated based on the difference between two given phr values ​​over a specified period of time, calculated by subtracting one number from the other.

[0092] In one embodiment, or in combination with any embodiment mentioned herein, the amount of solid contaminants in the PVB feed composition changes by at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, at least 10%, at least 11%, at least 12%, at least 13%, at least 14%, or at least 15%, and / or less than 25% by weight over a period of 1 hour, 6 hours, 12 hours, 18 hours, 1 day, 2 days, 3 days, 4 days, or 1 week. As above, this difference can be calculated based on the difference in two given weight percentages over a specified period of time, calculated by subtracting one number from the other.

[0093] In one embodiment, or in combination with any embodiment mentioned herein, the ratio of PVB resin to plasticizer in the PVB feed composition varies by at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, at least 10%, at least 11%, at least 12%, at least 13%, at least 14%, or at least 15%, and / or less than 25% over a period of 1 hour, 6 hours, 12 hours, 18 hours, 1 day, 2 days, 3 days, 4 days, or 1 week. As above, this difference can be calculated based on the difference between two given ratio values ​​over a specified period of time, calculated by subtracting one number from the other.

[0094] The above variability measurements can be measured by sampling the PVB feed composition at a specified time period (e.g., one week). To produce consistent measurements, a 20 gram sample of the PVB feed composition may be obtained and examined by solubility analysis as discussed above.

[0095] 1 and 2, the PVB feedstock 102 may be subjected to a size reduction operation in unit 104. The size reduction operation reduces the particle size of the PVB feed composition prior to its hydrolysis, as described above. Such size reduction may be provided, for example, by grinding / granulating, shredding, chopping, chopping, or other comminution processes that provide reduced-size PVB-containing composition particles. Such mechanical size reduction operations may include size reduction steps other than crushing and / or compacting.

[0096] In one embodiment, unit 104 reduces the average particle size of the individual pieces of PVB raw material 102 by at least 10%, at least 25%, at least 50%, or at least 75% of their original size. Additionally or alternatively, unit 104 reduces the average particle size of the individual pieces of PVB raw material 102 to an average particle size of less than about 400 microns, less than 350 microns, less than 300 microns, or less than 250 microns, or between about 200 microns and about 400 microns, between about 225 microns and about 375 microns, or between about 250 microns and about 350 microns. Additionally or alternatively, such as when PVB raw material 102 includes interlayer scrap, unit 104 reduces the average particle size of the individual pieces of PVB raw material 102 to "flakes" having dimensions of less than 10 mm x 10 mm, less than 8 mm x 8 mm, less than 6 mm x 6 mm, or less than 5 mm x 5 mm.

[0097] In some embodiments, the size-reduced PVB 106 discharged from unit 104 is optionally washed and then optionally treated to extract plasticizers therefrom in units 108 and 110, respectively. For example, in embodiments in which the PVB feed composition is derived from post-consumer scrap material, such as PVB flappers obtained from a glass recycler, unit 104 pre-washes the size-reduced PVB 106 to remove insoluble components therefrom. The pre-washing step may reduce the ash content of the PVB to less than about 0.5%, less than about 0.4%, less than about 0.3%, less than about 0.2%, or less than about 0.1% by weight of the PVB feed composition. The pre-washing step may also reduce the iron content of the PVB to less than about 50 ppm, less than about 40 ppm, less than about 30 ppm, less than about 20 ppm, less than about 10 ppm, or less than about 5 ppm.

[0098] In unit 108, the size-reduced PVB 106 is suspended in water and stirred for a period of time. The temperature of the water may be in the range of about 10 to about 100°C, about 20 to about 90°C, about 25 to about 75°C, or about 40 to about 60°C, and the PVB suspension may be stirred for at least 15 minutes, at least 30 minutes, at least 45 minutes, or at least 1 hour. In some embodiments, one or more metal-sequestering agents may be introduced into unit 108 to facilitate recovery of contaminants from the suspension. Exemplary metal-sequestering agents include, but are not limited to, citric acid, ethylenediaminetetraacetic acid (EDTA), and the like.

[0099] Additionally, the pH of the suspension may be maintained at an acidic level, for example, to neutralize any base remaining in the PVB flapper resulting from the deglassing step. The pH of the suspension may be maintained below about 7, below about 6, below about 5, below about 4, below about 3, below about 2, or below about 1, or between about 0 and about 5, between about 0 and about 4, between about 0 and about 3, between about 1 and about 2, or between about 1.5 and about 2. After the agitation period, the PVB may be filtered, rinsed on the filter with additional water to remove residual acid, and discharged from unit 108 as washed PVB 112.

[0100] In unit 110, plasticizers are extracted from the washed PVB 112. This optional plasticizer extraction step may be performed in embodiments where the PVB feed composition is derived, for example, from low-quality post-industrial PVB interlayer scrap. In such cases, the plasticizers are extracted from the washed PVB 112 prior to the hydrolysis step, allowing for hydrolysis to occur in an efficient manner. In some embodiments, the plasticizer extraction step is performed using supercritical carbon dioxide or by suspending the washed PVB 112 in an extraction solution. The extraction solution may include water, alcohol, and combinations thereof in various ratios. Exemplary alcohols include, but are not limited to, methanol, ethanol, and isopropanol.

[0101] The number of extraction stages performed may be based on the extraction time, extraction temperature, and / or polymer loading of the solution. For example, the extraction time may be at least 10 minutes, at least 30 minutes, at least 1 hour, at least 2 hours, at least 3 hours, or at least 4 hours in duration. The extraction temperature may be at least 10°C, at least 20°C, at least 30°C, or at least 40°C. Thus, based on these factors, at least one, at least two, at least three, or at least four extraction stages may be performed to reduce the phr of PVB to less than about 25, less than about 20, less than about 15, less than about 10, less than about 5, less than about 4, less than about 3, less than about 2, or less than about 1.

[0102] Following plasticizer extraction, the mixture of washed PVB 112 and extraction solution may be filtered, and the filtrate may be dried by evaporation of volatile materials to obtain dried PVB 114. Such volatile materials may be recovered, such as by distillation, and the plasticizer, alcohol, and / or water may be recycled for further use. The dried PVB 114 obtained from the plasticizer extraction step may be inspected to ensure that its average particle size is less than about 400 microns, less than 350 microns, less than 300 microns, or less than 250 microns, or between about 200 microns and about 400 microns, between about 225 microns and about 375 microns, or between about 250 microns and about 350 microns. Further size reduction may be performed, if necessary, to reduce the size of the dried PVB 114 to the above average particle size. In an alternative embodiment, unit 108 is located after the washing and plasticizer extraction steps.

[0103] 1 , dry PVB 114 is hydrolyzed in unit 116 to produce a solution 118 containing multiple hydrolysis products in the form of recycled content products derived directly from the PVB-containing composition. For example, as described in more detail below, the hydrolysis products may include some recycled content products derived from the hydrolysis of PVB resin. In the illustrated embodiment, dry PVB 114 may be hydrolyzed in the presence of water 120, alcohol 122, and optionally an acid catalyst 124 to produce a solution 118 containing regenerated PVOH, and a vapor stream 126.

[0104] Alternatively, in the embodiment shown in FIG. 2 , the dry PVB 114 may be dissolved in alcohol 122 prior to the hydrolysis step. For example, the dry PVB 114 may be fed to a dissolution and filtration unit 128, where the dry PVB 114 is mixed with a solvent, such as alcohol 122, for a residence time to facilitate dissolution of the dry PVB 114 in the alcohol 122 and produce a PVB solution 130. In some embodiments, dissolving the dry PVB 114 in a solvent facilitates identification of any remaining insoluble contaminants in the PVB feed composition remaining from the washing and / or plasticizer extraction steps. Any remaining contaminants may be filtered and removed from the resulting solution in unit 128 before being fed to unit 116.

[0105] The PVB solution 130 provided to unit 116 is hydrolyzed as described in more detail below. The dry PVB 114 may be fully or partially dissolved before being provided to unit 116. For example, the PVB solution 130 may have a total solids content of less than about 25%, less than about 20%, less than about 15%, less than about 10%, less than about 5%, less than about 2.5%, or less than about 1% by weight of the solution.

[0106] As a result of the hydrolysis reaction, PVB is typically converted to, for example, PVOH and butyraldehyde. The regenerated PVOH is typically soluble and therefore recovered in solution (i.e., in liquid form), and the regenerated butyraldehyde is reactively distilled (i.e., evaporated) from the solution. Thus, the r-PVOH solution 118 may contain regenerated PVOH, water, and residual amounts of polyvinyl acetate (PVAC), alcohol, catalyst, butyraldehyde, and / or butyral. Additionally, the vapor stream 126 may contain regenerated butyraldehyde and alcohol.

[0107] The degree of hydrolysis achieved (i.e., the conversion rate of PVB to PVOH) may be based on factors such as the presence of an acid catalyst, the concentration of the acid catalyst, if present, the reaction time, the polymer loading, the resin composition, and the reaction temperature. Without being bound by theory, it is believed that hydrolyzed PVB is soluble when its PVOH content is greater than a threshold PVOH content. Thus, the converted PVOH may be in the form of a water-insoluble PVB resin having a higher residual PVOH content than the PVB resin and / or a reduced butyraldehyde content. The converted PVOH may also be in the form of a water-soluble PVOH (i.e., PVB hydrolyzed to a PVOH content greater than a threshold).

[0108] In one embodiment, or in combination with any embodiment mentioned herein, the water-insoluble PVOH of the reaction product has a residual PVOH content of less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, between 20% and 90%, between 30% and 90%, between 40% and 90%, between 50% and 90%, between 50% and 80%, or between 50% and 70%. In other words, the water-soluble PVOH has a residual PVOH content of greater than 90%, greater than 95%, greater than 98%, greater than 99%, or 100%.

[0109] In exemplary embodiments, the aforementioned hydrolysis factors may be adjusted to obtain an average conversion of PVB to PVOH of at least 80%, at least 85%, at least 90%, at least 95%, at least 99%, between 80% and 99%, between 85% and 99%, between 90% and 99%, or between 95% and 99%.

[0110] Thus, in one embodiment, the resulting r-PVOH solution 118 comprises water, PVOH, and the balance being one or more additional components. The concentration of water in the r-PVOH solution 118 may be at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, at least 99%, or between 80% and 99%, between 85% and 99%, between 90% and 99%, or between 95% and 99% by weight of the r-PVOH solution 118.

[0111] The concentration of water-soluble PVOH in the r-PVOH solution 118 may be less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 5% by weight, less than 2% by weight, less than 1% by weight, or between 1% and 20% by weight, between 1% and 15% by weight, between 1% and 10% by weight, or between 1% and 5% by weight of the r-PVOH solution 118.

[0112] The concentration of the remainder may be less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 5 wt%, less than 2 wt%, less than 1 wt%, or between 1 wt% and 20 wt%, between 1 wt% and 15 wt%, between 1 wt% and 10 wt%, or between 1 wt% and 5 wt% of the r-PVOH solution 118.

[0113] The balance may include residual polyvinyl acetate (PVAC), residual alcohol, residual catalyst, butyraldehyde, and / or butyral, and the concentrations of these balances may comprise less than 5%, less than 2%, less than 1%, less than 0.5%, or less than 0.1% by weight of the r-PVOH solution 118, respectively.

[0114] As noted above, the conversion of PVB to PVOH may be based on a variety of factors. In one embodiment, or in combination with any embodiment mentioned herein, the hydrolysis step is carried out at a temperature in the range of about 70°C to about 250°C. Generally, the hydrolysis may be carried out at lower temperatures within this range when carried out in the presence of an acid catalyst 124. For example, hydrolysis carried out in the presence of an acid catalyst 124 may occur at temperatures in the range of about 70°C to about 150°C, about 70°C to about 140°C, about 75°C to about 130°C, or about 80°C to about 120°C. Exemplary acid catalysts include, but are not limited to, organic sulfonic acids, nitric acid, sulfuric acid, or hydrochloric acid.

[0115] Alternatively, the hydrolysis may be carried out at a higher temperature within the above ranges if the hydrolysis does not occur in the presence of acid catalyst 124. For example, the hydrolysis not carried out in the presence of acid catalyst 124 may occur at a temperature within the range of between about 150°C and about 250°C, between about 160°C and about 225°C, between about 170°C and about 220°C, or between about 175°C and about 200°C.

[0116] In one embodiment, or in combination with any embodiment mentioned herein, the hydrolysis step is carried out for a reaction time of at least 30 minutes, at least 1 hour, at least 2 hours, at least 4 hours, at least 8 hours, at least 16 hours, at least 32 hours, or at least 64 hours.

[0117] In one embodiment, or in combination with any embodiment mentioned herein, if present, the concentration of acid catalyst in the PVB hydrolysis solution (e.g., a mixture of dry PVB 114 or PVB solution 130, water 120, alcohol 122, and acid catalyst 124) is less than about 15% by weight, less than about 10% by weight, less than about 8% by weight, less than about 5% by weight, less than about 4% by weight, less than about 3% by weight, less than about 2% by weight, less than about 1% by weight, less than about 0.5% by weight, less than about 0.1% by weight, between about 0.5% by weight and about 10% by weight, between about 0.5% by weight and about 8% by weight, between about 0.5% by weight and about 5% by weight, between about 1% by weight and about 5% by weight, or between about 2% by weight and about 4% by weight of the hydrolysis solution.

[0118] In some embodiments, vapor stream 126 discharged from unit 116 may be directed to distillation / separation unit 132. As described above, vapor stream 126 comprises a mixture of regenerated butyraldehyde and alcohol. Unit 132 is operable to separate this mixture into its component parts, such that alcohol 134 and regenerated butyraldehyde 136 are discharged from unit 132 as separate streams. Alcohol 134 may be recycled for use in unit 116 (FIG. 1) or unit 128 (FIG. 2), and regenerated butyraldehyde 136 may be stored and / or directed for use in units downstream from unit 116, as described in further detail below.

[0119] In addition to residual PVAC, residual alcohol, residual catalyst, butyraldehyde, and / or butyral, the r-PVOH solution 118 may also contain one or more insoluble components remaining from the PVB washing step in unit 108 and / or produced in the hydrolysis reaction. Exemplary insoluble components include, but are not limited to, undissolved PVOH (e.g., water-insoluble PVB), debris, dirt, crosslinked polymer particles, gelled particles, metal particles, ceramic materials, rubber materials, adhesive materials, and polyurethanes. Accordingly, the r-PVOH solution 118 discharged from unit 116 may be optionally filtered in unit 138 and / or centrifuged in unit 140 to produce a filtered r-PVOH solution 142 that is substantially free of these insoluble components. For example, the filtration / centrifugation step(s) may be defined by a particle size retention of less than about 5 microns, less than about 4 microns, less than about 3 microns, less than about 2 microns, or less than about 1 micron.

[0120] A portion of the resulting filtered r-PVOH solution 142 may be recovered and stored for future use. Additionally, in the illustrated embodiment, a portion of the resulting filtered r-PVOH solution 142 may be used to produce regenerated PVB within chemical recycling facility 100. In one embodiment, or in combination with any of the 144 embodiments mentioned herein, r-PVOH solution 142 is cooled in unit 144 and then used to produce r-PVOH 146 in unit 148. In unit 144, r-PVOH solution 142 may be cooled to less than 150°C, less than 125°C, less than 100°C, less than 75°C, less than 50°C, less than 25°C, less than 15°C, less than 10°C, between 10°C and 150°C, between 10°C and 125°C, between 10°C and 100°C, between 15°C and 75°C, or between 25°C and 50°C. Thus, the r-PVOH solution 142 is cooled to a temperature that promotes PVB formation in unit 148 .

[0121] In unit 148, the r-PVOH solution 142 is mixed with water 150 and butyraldehyde, optionally in the presence of acid catalyst 124, to produce r-PVB 146. The butyraldehyde may be provided as fresh butyraldehyde 152 and / or as recycled r-butyraldehyde 136 from unit 132. Fresh PVOH 154 may also be provided to unit 148 to produce r-PVB 146.

[0122] As used herein, "new" refers to components that are provided from a source other than the PVB hydrolysis reaction described herein. For example, the components may be purchased or manufactured in another industrial process.

[0123] In one embodiment, or in combination with any embodiment mentioned herein, the r-PVB 146 is inspected in unit 156 for defects including at least one of oversize, visual defects, compositional defects, gelation, or contamination. PVB produced from the reaction of water, PVOH, and butyraldehyde is generally defined herein as "in-spec" and "out-of-spec" based on inspection for such defects. In-spec PVB does not have any of the defects described above. Out-of-spec PVB has at least one of the defects described above. In unit 156, the in-spec PVB 158 is separated from the out-of-spec PVB 160 based on the inspection. The in-spec PVB 158 is discharged from unit 156 and collected. In the illustrated embodiment, the out-of-spec PVB 160 is discharged from unit 156 and, optionally, if oversized, is reduced in size in unit 162 and directed to unit 116, from which additional recycled PVOH is produced.

[0124] 3 and 4, chemical recycling facility 164 is designed to produce PVB particles from the reaction of fresh feedstock components and to process (i.e., hydrolyze) off-spec PVB particles to produce recycled PVOH, which may be used to produce additional PVB particles. In the exemplary diagram, fresh PVOH 166, fresh butyraldehyde 168, water 170, and optionally acid catalyst 172 (e.g., acid catalyst 124) and r-butyraldehyde 174 are combined in unit 176 to produce PVB particles 178.

[0125] In one embodiment, or in combination with any embodiment mentioned herein, PVB particles 178 are inspected in unit 180 for defects including at least one of oversizing, visual defects, compositional defects, gelation, or contamination. In unit 180, on-spec PVB 182 is separated from off-spec PVB 184 based on the inspection. On-spec PVB 182 is discharged from unit 180 and collected. Off-spec PVB 184 is discharged from unit 180 and optionally reduced in size in unit 186 based on process conditions associated with unit 104 (shown in FIGS. 1 and 2 ) and directed to unit 188, from which r-PVOH is produced.

[0126] 3, off-spec PVB 184 is hydrolyzed in unit 188 to produce a solution 190 containing recycled PVOH and a vapor stream 192. The off-spec PVB 184 may be hydrolyzed in the presence of water 194, alcohol 196, and optionally, acid catalyst 172 to produce r-PVOH solution 190. The hydrolysis is carried out according to the process conditions associated with unit 116 (as shown in FIGS. 1 and 2), as described above.

[0127] A portion of the resulting r-PVOH solution 190 may be recovered and stored for future use. Additionally, in the illustrated embodiment, a portion of the r-PVOH solution 190 may be used to produce recycled PVB particles at chemical recycling facility 164. In one embodiment, or in combination with embodiments mentioned herein, r-PVOH solution 190 is cooled in unit 198 and then used to produce additional PVB particles 178 in unit 176.

[0128] 4, the off-spec PVB 184 may be dissolved in alcohol 196 prior to the hydrolysis step. For example, the off-spec PVB 184 may be fed to a dissolution unit 200 where the off-spec PVB 184 is mixed with a solvent, such as alcohol 196, for a residence time to facilitate dissolution of the off-spec PVB 184 in the alcohol 196 to produce a PVB solution 202. The PVB solution 202 may then be fed to unit 188 and hydrolyzed as described above. The off-spec PVB 184 may be fully or partially dissolved before being fed to unit 188.

[0129] 3 and 4, vapor stream 192 discharged from unit 188 may be directed to distillation / separation unit 204. Vapor stream 192 comprises a mixture of recycled butyraldehyde and alcohol. Unit 204 is operable to separate this mixture into its component parts, such that alcohol 196 and recycled butyraldehyde 174 are discharged from unit 204 as separate streams. Alcohol 196 may optionally be recycled for use in unit 188 (FIG. 3) or unit 200 (FIG. 4), and recycled butyraldehyde 174 may be stored and / or directed for use in producing PVB particles 178 in unit 176, as described above.

[0130] 5 and 6, dry PVB 114 is partially hydrolyzed in unit 116 to produce a reaction product including multiple hydrolysis products in the form of recycled content products derived directly from the PVB-containing composition. For example, the hydrolysis product may include some recycled content products derived from the hydrolysis of PVB resin, as described above. In the illustrated embodiment, dry PVB 114 may be hydrolyzed in the presence of water 120, alcohol 122, and optionally an acid catalyst 124 to produce a reaction product including water-insoluble PVB having a higher residual PVOH content than the PVB resin, and vapor stream 126. As described in more detail below, the partial hydrolysis of the PVB-containing composition limits the solubility of PVB so that the reaction product is in the form of, for example, a PVB slurry 204 of insoluble PVB in the liquid discharged from unit 116.

[0131] For example, the degree of hydrolysis achieved in unit 116 (i.e., the conversion rate of PVB to PVOH) can be controlled by adjusting factors such as the presence of an acid catalyst, the concentration of the acid catalyst, if present, the reaction time, the polymer loading, the resin composition, and the reaction temperature. Without being bound by theory, it is believed that hydrolyzed PVB is soluble when its PVOH content is greater than a threshold PVOH content. Thus, the converted PVOH may be in the form of a water-insoluble PVB resin having a higher residual PVOH content and / or a lower butyraldehyde content than PVB resin. The converted PVOH may also be in the form of a water-soluble PVOH (i.e., PVB hydrolyzed to a PVOH content greater than a threshold).

[0132] In the embodiments shown in Figures 5-10, the aforementioned hydrolysis factors are adjusted to produce a reaction product that is partially hydrolyzed. As used herein, "partial hydrolysis" refers to a process in which PVB is hydrolyzed to produce a reaction product containing water-insoluble PVB. Partial hydrolysis may be defined by a reduction in the PVB content of the PVB feed composition (i.e., due to the conversion of water-insoluble PVB to water-soluble PVOH) by at least 10 wt%, at least 20 wt%, at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, or up to 100 wt% of its starting PVB content. Alternatively, partial hydrolysis may be defined by a reduction in the acetal content of the PVB feed composition by at least 10 wt%, at least 20 wt%, at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, or up to 100 wt% of its starting acetal content. Thus, partial hydrolysis produces a reaction product that includes one or both of water-insoluble PVB and water-soluble PVOH.

[0133] In one embodiment, or in combination with any embodiment mentioned herein, the water-insoluble PVOH of the reaction product has a residual PVOH content of less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, between 20% and 90%, between 30% and 90%, between 40% and 90%, between 50% and 90%, between 50% and 80%, or between 50% and 70%. In other words, the water-soluble PVOH has a residual PVOH content of greater than 90%, greater than 95%, greater than 98%, greater than 99%, or 100%.

[0134] In one embodiment, or in combination with any embodiment mentioned herein, the partial hydrolysis step is carried out at a temperature in the range of about 70° C. to about 250° C. Generally, the hydrolysis may be carried out at lower temperatures within this range when carried out in the presence of acid catalyst 124. For example, hydrolysis carried out in the presence of acid catalyst 124 may occur at a temperature in the range of between about 70° C. and about 150° C., between about 70° C. and about 140° C., between about 75° C. and about 130° C., or between about 80° C. and about 120° C. Exemplary acid catalysts include, but are not limited to, organic sulfonic acids, nitric acid, sulfuric acid, or hydrochloric acid.

[0135] Alternatively, the hydrolysis may be carried out at a higher temperature within the above ranges if the hydrolysis does not occur in the presence of acid catalyst 124. For example, the hydrolysis not carried out in the presence of acid catalyst 124 may occur at a temperature within the range of between about 150°C and about 250°C, between about 160°C and about 225°C, between about 170°C and about 220°C, or between about 175°C and about 200°C.

[0136] In one embodiment, or in combination with any embodiment mentioned herein, the hydrolysis step is carried out for a reaction time of at least 30 minutes, at least 1 hour, at least 2 hours, at least 4 hours, at least 8 hours, at least 16 hours, at least 32 hours, or at least 64 hours.

[0137] 5-7, the reaction product discharged from unit 116 is in the form of PVB slurry 204, which includes water-insoluble PVB and water. In one embodiment, or in combination with any embodiment mentioned herein, PVB slurry 204 includes less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 5 wt%, between 0 wt% and 25 wt%, between 1 wt% and 25 wt%, between 5 wt% and 25 wt%, or between 10 wt% and 20 wt% water-insoluble PVB. Further, in one embodiment, or in combination with any embodiment mentioned herein, PVB slurry 204 includes more than 25 wt%, more than 50 wt%, more than 75 wt%, between 25 wt% and 75 wt%, between 30 wt% and 70 wt%, between 35 wt% and 65 wt%, or between 40 wt% and 60 wt% water.

[0138] In the illustrated embodiment, PVB slurry 204 is used to produce r-PVB 206 in unit 208. Specifically, in unit 208, PVB slurry 204 is combined with water 210 and butyraldehyde, optionally in the presence of acid catalyst 124, to produce r-PVB 206. That is, residual PVOH from the water-insoluble PVB in PVB slurry 204 is reacted with butyraldehyde to produce r-PVB 206. The butyraldehyde may be provided as fresh butyraldehyde 212 and / or as recycled butyraldehyde 136 recycled from unit 132.

[0139] As shown in Figures 5 and 6, the partial hydrolysis and PVOH acetalization (reaction) steps are carried out in separate units 116 and 208, respectively. Alternatively, in the embodiment shown in Figure 7, the partial hydrolysis and PVOH acetalization steps are carried out in the same unit 216. For example, partial hydrolysis of dried PVB 114 may be carried out in unit 216 as described above. After the PVB has been converted to the desired extent, one or more of fresh butyraldehyde 212 or recycled butyraldehyde 136 may be fed to the unit to produce r-PVB 206 therefrom.

[0140] Because PVOH acetalization reduces the PVOH content in PVB, r-PVB 206 has a lower residual PVOH content than water-insoluble PVB. In some embodiments, PVOH acetalization is controlled to achieve a target residual PVOH content in r-PVB 206. In one embodiment, or in combination with any embodiment mentioned herein, the r-PVB produced has a residual PVOH content (e.g., a target residual PVOH content) of between 1% and 90%, between 5% and 30%, between 7% and 30%, or between 16% and 20%.

[0141] 8-10, PVB particles 178 are produced from the reaction of fresh feedstock components, such as fresh PVOH 166 and fresh butyraldehyde 168, as well as water 170, optionally acid catalyst 124, and r-butyraldehyde 174. In one embodiment, or in combination with any embodiment mentioned herein, PVB particles 178 are inspected for defects in unit 180. Based on the inspection, on-spec PVB 182 is separated from off-spec PVB 184.

[0142] 8 and 9 , off-spec PVB 184 is partially hydrolyzed in unit 188 to produce a reaction product including multiple hydrolysis products in the form of recycled content products derived directly from the PVB-containing composition. For example, the hydrolysis product may include some recycled content products derived from the hydrolysis of PVB resin, as described above. In the illustrated embodiment, off-spec PVB 184 is hydrolyzed in the presence of water 120, alcohol 122, and optionally an acid catalyst 124 to produce a reaction product including water-insoluble PVB having a higher residual PVOH content than PVB resin, and vapor stream 192. As described above, the solubility of the partially hydrolyzed PVB is based on the extent of hydrolysis performed on the PVB-containing composition. Thus, in some embodiments, the reaction product is in the form of PVB slurry 218 discharged from unit 116.

[0143] In the illustrated embodiment, PVB slurry 218 is used to produce r-PVB 220 in unit 208. Specifically, in unit 208, PVB slurry 218 is combined with water 222 and butyraldehyde, optionally in the presence of acid catalyst 124, to produce r-PVB 220. That is, residual PVOH from the water-insoluble PVB in PVB slurry 218 is reacted with butyraldehyde to produce r-PVB 220. The butyraldehyde may be provided as fresh butyraldehyde 224 and / or as recycled butyraldehyde 174 recycled from unit 204.

[0144] As shown in Figures 8 and 9, the partial hydrolysis and PVOH acetalization (reaction) steps are carried out in separate units 188 and 208, respectively. Alternatively, in the embodiment shown in Figure 10, the partial hydrolysis and PVOH acetalization steps are carried out in the same unit 216. For example, partial hydrolysis of off-spec PVB 184 may be carried out in unit 216 as described above. After the PVB has been converted to the desired extent, one or more of fresh butyraldehyde 224 or recycled butyraldehyde 174 may be fed to unit 216 to produce r-PVB 220 therefrom.

[0145] In one embodiment, or in combination with any embodiment mentioned herein, the r-PVB 220 is inspected for defects including at least one of oversizing, visual defects, compositional defects, gelling, or contamination in inspection unit 225. In unit 225, the on-spec PVB 227 is separated from the off-spec PVB 228 based on the inspection. The on-spec PVB 227 is discharged from unit 225 and collected. The off-spec PVB 228 is discharged from unit 225 and optionally sized in unit 186 and recycled to unit 188 from which additional PVB slurry 218 is produced.

[0146] 11 and 12, PVB 230 (e.g., dried PVB 114, PVB solution 130, off-spec PVB 184, or PVB solution 202) is directed to hydrolysis unit 229 and hydrolyzed as described above to produce a solution including multiple hydrolysis products in the form of recycled content products derived directly from the PVB-containing composition. For example, the hydrolysis products may include some recycled content products derived from the hydrolysis of PVB resin as described above. In the illustrated embodiment, PVB may be hydrolyzed in the presence of water 120, an aldehyde scavenger 232, and optionally an alcohol 122 and an acid catalyst 124 to produce a solution including regenerated PVOH and regenerated acetal.

[0147] Without being bound by any particular theory, it is believed that the aldehyde scavenger 232 reacts with the converted butyraldehyde, thereby limiting its conversion back to PVB. That is, the aldehyde scavenger 232 reacts with the butyraldehyde to produce an acetal (i.e., dioxane (1,3-dioxane, glycol acetal, glycol butyral)), which is generally soluble in the reaction product along with the regenerated PVOH. In this way, the hydrolysis reaction is driven toward the production of PVOH, and a mixture 234 containing the regenerated PVOH and the acetal is produced therefrom. Examples of aldehyde scavengers include, but are not limited to, C2 glycols (e.g., ethylene glycol), propanediol, methanol, ethanol, and acetoacetate.

[0148] Thus, mixture 234 comprises the balance of water, PVOH, acetal, water-insoluble PVB, and / or one or more additional components. The concentration of water may be greater than 25%, greater than 50%, greater than 75%, greater than 80%, greater than 85%, greater than 90%, greater than 95%, greater than 98%, greater than 99%, between 25% and 75%, between 30% and 70%, between 35% and 65%, or between 40% and 60%, between 80% and 99%, between 85% and 99%, between 90% and 99%, or between 95% and 99% by weight of mixture 234.

[0149] The concentration of the water-soluble PVOH may be less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 5% by weight, less than 2% by weight, less than 1% by weight, or between 1% and 20% by weight, between 1% and 15% by weight, between 1% and 10% by weight, or between 1% and 5% by weight of the mixture 234.

[0150] The concentration of acetal may be between 1% and 25% by weight, between 1% and 20% by weight, between 1% and 15% by weight, or between 5% and 15% by weight of mixture 234.

[0151] The concentration of the water-insoluble PVB may be less than 25% by weight, less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 5% by weight, between 0% and 25% by weight, between 1% and 25% by weight, between 5% and 25% by weight, or between 10% and 20% by weight of the mixture 234.

[0152] The concentration of the remainder may be less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 5% by weight, less than 2% by weight, less than 1% by weight, or between 1% and 20% by weight, between 1% and 15% by weight, between 1% and 10% by weight, or between 1% and 5% by weight of the mixture 234.

[0153] The balance may include residual polyvinyl acetate (PVAC), residual alcohol, residual catalyst, butyraldehyde, and / or butyral, and the concentrations of these balances may be less than 5%, less than 2%, less than 1%, less than 0.5%, or less than 0.1% by weight of mixture 234, respectively.

[0154] 11 , mixture 234 may also include one or more insoluble components. Therefore, mixture 234 may optionally be filtered in unit 138 and / or centrifuged in unit 140. In some embodiments, the solution is cooled in unit 144 and then used to produce r-PVB 236 in unit 148.

[0155] In unit 148, the filtered and cooled mixture 234 is combined with water 150, fresh butyraldehyde 152, and fresh PVOH 154, optionally in the presence of acid catalyst 124, to produce r-PVB 236 and liquid product 238. r-PVB 236 may be processed as described above. In one embodiment, or in combination with any embodiment mentioned herein, liquid product 238 comprises acetal and water, which may be separated and processed in downstream units.

[0156] 12, once filtered and / or centrifuged, mixture 234 may be processed to recover regenerated PVOH and regenerated acetal therefrom. Specifically, in the illustrated embodiment, a portion of mixture 234 is directed to a removal unit 250, where at least one of regenerated PVOH 252 or aldehyde scavenger 254 is removed from the solution. The regenerated PVOH may be recovered and stored, for example, for use in producing regenerated PVB, and the aldehyde scavenger 254 may be recycled for further use in the hydrolysis step. Additionally, regenerated acetal 256 may be recovered and stored for future use and / or processing.

[0157] In some embodiments, another portion of mixture 234 is processed in precipitation unit 260 and liquid-liquid extraction unit 262 to recover regenerated PVOH and regenerated acetal therefrom. In precipitation unit 260, mixture 234 is combined with alcohol 264 to precipitate regenerated PVOH 266 therefrom. A resulting liquid product 268 comprising alcohol, water, and acetal is discharged from precipitation unit 260 and received in extraction unit 262. In extraction unit 262, liquid product 268 is combined with extractant 270, such as toluene, to recover water 272 and liquid product 274 comprising the extractant, alcohol, and acetal.

[0158] In the illustrated embodiment, acetal 276, alcohol 278, and extractant 280 are recovered from liquid product 274 in distillation / separation unit 282. In some embodiments, a portion of acetal 276 may be directed to hydrolysis unit 286 to react with water 288 to produce liquid product 290 comprising regenerated aldehyde 292 and alcohol 294, which may be recovered in distillation / separation unit 296. In some embodiments, regenerated aldehyde 292 may be directed to a PVOH acetalization unit for use in producing additional PVOH.

[0159] 13 and 14, PVB 230 (e.g., dried PVB 114, PVB solution 130, off-spec PVB 184, or PVB solution 202) is conducted to hydrolysis unit 298 and hydrolyzed as described above to produce a solution containing multiple hydrolysis products in the form of recycled content products derived directly from the PVB-containing composition. For example, the hydrolysis products may include some recycled content products derived from the hydrolysis of PVB resin as described above. In the illustrated embodiment, PVB 230 may be hydrolyzed in the presence of water 120, at least one amino-functional compound 300, and optionally alcohol 122 and acid catalyst 124 to produce a solution containing regenerated PVOH and one or more butylimine derivatives.

[0160] Without being bound by any particular theory, it is believed that amino-functional compound 300 reacts with the converted butyraldehyde, thereby limiting its conversion back to PVB. That is, amino-functional compound 300 reacts with butyraldehyde to produce one or more butylimine derivatives. Thus, the hydrolysis reaction promotes the production of PVOH, and a mixture 302 containing regenerated PVOH and one or more butylimine derivatives is produced therefrom.

[0161] Exemplary amino-functional compounds include, but are not limited to, monofunctional amines, difunctional amines, aromatic amines, ethanolamine, methylamine, ethylamine, ethyldiamine, propyldiamine, butylamine, or ammonia. Thus, the butylimine derivative produced is based on the amino-functional compound used in unit 298. For example, the butylimine derivative may be a monofunctional (i.e., unsaturated) derivative or a difunctional (i.e., saturated) derivative. Exemplary monofunctional derivatives include, but are not limited to, imines and enamines. Exemplary difunctional derivatives include, but are not limited to, oxazolidines and imidazolidines.

[0162] Thus, mixture 302 includes water, PVOH, one or more butylimine derivatives, water-insoluble PVB, and the balance being one or more additional components. The concentration of water may be greater than 25%, greater than 50%, greater than 75%, greater than 80%, greater than 85%, greater than 90%, greater than 95%, greater than 98%, greater than 99%, between 25% and 75%, between 30% and 70%, between 35% and 65%, or between 40% and 60%, between 80% and 99%, between 85% and 99%, between 90% and 99%, or between 95% and 99% by weight of mixture 302.

[0163] The concentration of the water-soluble PVOH may be less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 5% by weight, less than 2% by weight, less than 1% by weight, or between 1% and 20% by weight, between 1% and 15% by weight, between 1% and 10% by weight, or between 1% and 5% by weight of the mixture 302.

[0164] The concentration of the butylimine derivative may be between 1% and 25% by weight, between 1% and 20% by weight, between 1% and 15% by weight, or between 5% and 15% by weight of mixture 302.

[0165] The concentration of the water-insoluble PVB may be less than 25% by weight, less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 5% by weight, between 0% and 25% by weight, between 1% and 25% by weight, between 5% and 25% by weight, or between 10% and 20% by weight of the mixture 302.

[0166] The concentration of the remainder may include less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 5% by weight, less than 2% by weight, less than 1% by weight, or between 1% and 20% by weight, between 1% and 15% by weight, between 1% and 10% by weight, or between 1% and 5% by weight of the mixture 302.

[0167] The balance may include residual polyvinyl acetate (PVAC), residual alcohol, residual catalyst, butyraldehyde, and / or butyral, and the concentration of these balances may be less than 5%, less than 2%, less than 1%, less than 0.5%, or less than 0.1% by weight of the mixture 302, respectively.

[0168] 13, mixture 302 may also include one or more insoluble components. Therefore, mixture 302 may optionally be filtered in unit 138 and / or centrifuged in unit 140. The solution is cooled in unit 144 and then used to produce r-PVB 304 in unit 148.

[0169] In unit 148, the filtered and cooled mixture 302 is combined with water 150, fresh butyraldehyde 152, and fresh PVOH 154, optionally in the presence of acid catalyst 124, to produce r-PVB 304 and liquid product 306. r-PVB 304 may be processed as described above. In one embodiment, or in combination with any embodiment described herein, liquid product 306 comprises one or more butylimine derivatives and water.

[0170] 14, once filtered and / or centrifuged, mixture 302 may be processed to recover regenerated PVOH and one or more butylimine derivatives therefrom. Specifically, in the illustrated embodiment, mixture 302 is processed in precipitation unit 260 to recover regenerated PVOH therefrom. In precipitation unit 260, mixture 302 is combined with alcohol 264 to precipitate regenerated PVOH 314 therefrom. A resulting liquid product 316 comprising alcohol, water, and one or more butylimine derivatives is discharged from precipitation unit 260, from which it may be recovered and / or further processed to recover the butylimine derivatives therefrom.

[0171] 15, PVB 230 (e.g., dried PVB 114, PVB solution 130, off-spec PVB 184, or PVB solution 202) is conducted to hydrolysis unit 326 and hydrolyzed as described above to produce a mixture including multiple hydrolysis products in the form of recycled content products derived directly from the PVB-containing composition. For example, the hydrolysis products may include some recycled content products derived from the hydrolysis of PVB resin, as described above. In the illustrated embodiment, PVB 230 may be hydrolyzed in the presence of water 120, hydrogen 328, hydrogenation catalyst 330, and optionally alcohol 122 and acid catalyst 124 to produce a mixture including recycled PVOH and recycled butanol.

[0172] Without being bound by any particular theory, it is believed that hydrogen 328 and hydrogenation catalyst 330 react with the converted butyraldehyde, thereby limiting its conversion back to PVB. That is, hydrogen 328 and hydrogenation catalyst 330 react with butyraldehyde to produce, for example, butanol. Thus, the hydrolysis reaction drives the production of PVOH, and a mixture 332 containing recycled PVOH and recycled butanol is produced therefrom.

[0173] Exemplary hydrogenation catalysts include, but are not limited to, Group 8 metals (e.g., iron (Fe), ruthenium (Ru), osmium (Os), and hassium (Hs)). Hydrogenation catalyst 330 may comprise one or more different hydrogenation catalysts. Additionally, hydrogenation catalyst 330 may be heterogeneous or homogeneous.

[0174] Thus, mixture 332 includes water, PVOH, butanol, water-insoluble PVB, and the balance being one or more additional components. The concentration of water may be greater than 25%, greater than 50%, greater than 75%, greater than 80%, greater than 85%, greater than 90%, greater than 95%, greater than 98%, greater than 99%, between 25% and 75%, between 30% and 70%, between 35% and 65%, or between 40% and 60%, between 80% and 99%, between 85% and 99%, between 90% and 99%, or between 95% and 99% by weight of mixture 332.

[0175] The concentration of the water-soluble PVOH may be less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 5% by weight, less than 2% by weight, less than 1% by weight, or between 1% and 20% by weight, between 1% and 15% by weight, between 1% and 10% by weight, or between 1% and 5% by weight of the mixture 332.

[0176] The concentration of butanol may be between 1% and 25% by weight, between 1% and 20% by weight, between 1% and 15% by weight, or between 5% and 15% by weight of mixture 332.

[0177] The concentration of the water-insoluble PVB may be less than 25% by weight, less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 5% by weight, between 0% and 25% by weight, between 1% and 25% by weight, between 5% and 25% by weight, or between 10% and 20% by weight of the mixture 332.

[0178] The concentration of the remainder may be less than 20% by weight, less than 15% by weight, less than 10% by weight, less than 5% by weight, less than 2% by weight, less than 1% by weight, or between 1% and 20% by weight, between 1% and 15% by weight, between 1% and 10% by weight, or between 1% and 5% by weight of mixture 332.

[0179] The balance may include residual polyvinyl acetate (PVAC), residual alcohol, residual catalyst, butyraldehyde, and / or butyral, and the concentrations of these balances may be less than 5%, less than 2%, less than 1%, less than 0.5%, or less than 0.1% by weight of mixture 332, respectively.

[0180] In one embodiment, or in combination with any embodiment mentioned herein, the hydrolysis in unit 326 is carried out in, for example, one of a continuous stirred tank reactor, a bubble column reactor, a fixed bed / trickle bed reactor, or an autoclave reactor. Thus, mixture 332 may include a variety of compositions based on the type of reactor used to carry out the hydrolysis step.

[0181] For example, in one embodiment, mixture 332 includes water, PVOH, butanol, hydrogen, and a hydrogenation catalyst. In such an embodiment, mixture 332 is directed to settling / separation unit 334 to recover a vapor phase 336, a liquid phase 338, and a solid phase 340. Regenerated butanol and hydrogen may be recovered from vapor phase 336. Regenerated PVOH, regenerated butanol, and water may be recovered from liquid phase 338. Regenerated butanol may be recovered from liquid phase 338, for example, by liquid-liquid extraction. The hydrogenation catalyst may be recovered from solid phase 340.

[0182] Alternatively, for example, in a fixed-bed / trickle-bed reactor, hydrogenation catalyst 330 remains in the reactor such that mixture 332 comprises water, PVOH, butanol, and hydrogen. In such an embodiment, mixture 332 is directed to settling / separation unit 334, and only vapor phase 336 and liquid phase 338 are recovered. Regenerated butanol and hydrogen may be recovered from vapor phase 336. Regenerated PVOH, regenerated butanol, and water may be recovered from liquid phase 338.

[0183] In additional numbered embodiments and sub-embodiments:

[0184] Embodiment A1. A method for recycling polyvinyl butyral (PVB), the method comprising: partially hydrolyzing raw PVB material to produce a reaction product comprising water-insoluble PVB and butyraldehyde, wherein the water-insoluble PVB comprises residual polyvinyl alcohol (PVOH); and reacting the residual PVOH with additional butyraldehyde to produce regenerated PVB.

[0185] A2. The method of A1, wherein the partial hydrolysis of the PVB raw material has a conversion rate of less than 90%, less than 80%, less than 70%, less than 60%, or less than 50%.

[0186] A3. The method of A1 or A2, wherein the partial hydrolysis produces a slurry in water comprising the water-insoluble PVB.

[0187] A4. The method of any of A1-A3, wherein the partial hydrolysis of the PVB raw material produces a slurry containing between 25% and 75% by weight, between 30% and 70% by weight, between 35% and 65% by weight, or between 40% and 60% by weight of water-insoluble PVB.

[0188] A5. The method of any of A1-A4, wherein the partial hydrolysis of the PVB raw material produces a slurry containing more than 25 wt%, more than 50 wt%, more than 75 wt%, between 25 wt% and 75 wt%, between 30 wt% and 70 wt%, between 35 wt% and 65 wt%, or between 40 wt% and 60 wt% water.

[0189] A6. The method according to any one of A1 to A5, wherein the water-insoluble PVB has a higher residual PVOH content than the PVB raw material.

[0190] A7. The method according to any one of A1 to A6, wherein the recycled PVB has a lower residual PVOH content than the water-insoluble PVB.

[0191] A8. The method of any of A1-A7, wherein the partial hydrolysis of the PVB raw material produces a water-insoluble PVB having a residual PVOH content of less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, between 20% and 90%, between 30% and 90%, between 40% and 90%, between 50% and 90%, between 50% and 80%, or between 50% and 70%.

[0192] A9. The method of any of A1-A8, further comprising reacting the residual PVOH to produce recycled PVB having a residual PVOH content of between 1% and 90%, between 5% and 30% or less, between 7% and 30%, or between 16% and 20%.

[0193] A10. The method of any of A1-A9, further comprising reacting the residual PVOH to produce the recycled PVB having a target residual PVOH content, wherein the PVB feedstock has a residual PVOH content that is 1% greater, 2% greater, 3% greater, 4% greater, 5% greater, or 10% greater than the target residual PVOH content.

[0194] A11. The method of any one of A1 to A10, further comprising reacting the residual PVOH with fresh butyraldehyde to produce the recycled PVB.

[0195] A12. The method according to any one of A1 to A11, further comprising carrying out the partial hydrolysis and reaction steps in separate units.

[0196] A13. The method according to any one of A1 to A12, further comprising carrying out the partial hydrolysis and reaction steps in the same unit.

[0197] A14. The method according to any one of A1 to A13, wherein the partial hydrolysis is carried out in the presence of an acid catalyst.

[0198] A15. The method of A14, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0199] A16. The method of A14 or A15, further comprising producing the regenerated PVB in the presence of the same acid catalyst used in the partial hydrolysis step.

[0200] A17. The method according to any one of A1 to A16, wherein the partial hydrolysis is carried out at a temperature within the range of about 70°C to about 250°C.

[0201] A18. The method of any of A14 to A17, wherein the partial hydrolysis is carried out at a temperature in the range of about 70°C to about 150°C when the hydrolysis step occurs in the presence of the acid catalyst.

[0202] A19. The method of any of A1-A13 or A17, wherein the partial hydrolysis is carried out at a temperature in the range of about 150°C to about 250°C if the hydrolysis step does not occur in the presence of the acid catalyst.

[0203] A20. The method according to any one of A1 to A19, wherein the partial hydrolysis is carried out in the presence of an alcohol.

[0204] A21. The method according to any one of A1 to A20, further comprising dissolving the PVB raw material in a solvent before partially hydrolyzing the PVB raw material.

[0205] A22. The method of any of A20 and A21, further comprising dissolving the PVB raw material in the solvent comprising the alcohol.

[0206] A23. The method according to any one of A1 to A22, further comprising recovering butyraldehyde produced from the partial hydrolysis of the PVB feedstock.

[0207] A24. The method according to A23, further comprising producing the recycled PVB from the recovered butyraldehyde.

[0208] A25. A method according to any one of A1 to A24, comprising inspecting the recycled PVB for at least one of oversizing, visual defects, compositional defects, gelling, or contamination; separating in-spec PVB from substandard PVB based on the inspection; and partially hydrolyzing the substandard PVB to increase the residual PVOH content of the substandard PVB.

[0209] A26. The method of A25, further comprising sizing the off-spec PVB prior to said partially hydrolyzing the off-spec PVB.

[0210] A27. The method of either A25 or A26, further comprising sizing the off-spec PVB to an average particle size of less than about 400 microns, less than 300 microns, or less than 200 microns, or between about 200 and about 400 microns.

[0211] A28. The method of any one of A1 to A27, further comprising sizing the PVB raw material prior to partially hydrolyzing the PVB raw material.

[0212] A29. The method of any of embodiments A1-A28, further comprising, prior to said partial hydrolysis of said PVB raw material, size reducing said PVB raw material to an average particle size of less than about 400 microns, 350 microns, 300 microns, or 250 microns, or between about 200 microns and about 400 microns, between about 225 microns and about 375 microns, or between about 250 microns and about 350 microns.

[0213] A30. The method according to any one of A1 to A29, wherein the PVB raw material contains two or more PVB resins having different compositions.

[0214] A31. The method according to any one of A1 to A30, wherein the PVB raw material comprises two or more PVB resins having different residual PVOH contents.

[0215] A32. The method according to any one of A1 to A31, further comprising extracting a plasticizer from the PVB raw material before partially hydrolyzing the PVB raw material.

[0216] A33. The method of A32, further comprising extracting plasticizers from said PVB raw material, wherein said PVB raw material is derived from at least one of industrial waste or post-consumer scrap material.

[0217] A34. The method according to any one of A1 to A33, further comprising washing the PVB raw material to remove insoluble components before partially hydrolyzing the PVB raw material.

[0218] A35. The PVB raw material is at least 8%, at least 9%, at least 9.5%, at least 10%, at least 10.5%, at least 11%, at least 11.5%, at least 12%, at least 12.5%, at least 13%, at least 13.5%, at least 14%, at least 14.5%, at least 15%, at least 15.5%, at least 16%, at least 16.5%, at least 17%, at least 17.5%, at least 18%, at least 18.5, at least 19, at least 19.5, at least 20, at least 25, at least 26, at least 30, the method of any of A1-A34, having a residual PVOH content of at least 32%, at least 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, and / or no more than 100%, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 35% or less, 32% or less, 30% or less, 25% or less, 22% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, or 8% or less.

[0219] A36. The method of any of A1-A35, wherein the PVB stock comprises at least 1, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, or at least 90 phr, and / or no more than 100, no more than 90, no more than 85, no more than 80, no more than 75, no more than 70, no more than 65, no more than 60, no more than 55, no more than 50, no more than 45, no more than 40, no more than 35, no more than 30, no more than 25, no more than 20, no more than 15, or no more than 10 phr of plasticizer, based on the total weight of the PVB stock.

[0220] A37. The method of any of A1-A36, wherein the PVB raw material comprises solid particles having an average particle size of at least 0.01 inches, at least 0.05 inches, at least 0.1 inches, at least 0.2 inches, at least 0.3 inches, at least 0.4 inches, at least 0.5 inches, at least 1 inch, or at least 2 inches.

[0221] A38. The method of any of A1-A37, wherein the PVB raw material contains less than 10 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt%, or less than 0.5 wt%, of solid contaminants, based on the total weight of the PVB raw material.

[0222] A39. The method of any of A1-A38, wherein the PVB raw material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, less than 40 wt%, less than 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt%, of insoluble components, based on the total weight of the PVB raw material.

[0223] A40. The method of A39, wherein the insoluble component comprises at least one polymer, the polymer comprising a polyolefin, polyester, rubber, polyamide, polystyrene, or a combination thereof, and the PVB raw material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, less than 40 wt%, less than 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt% of the polymer.

[0224] A41. The method of A39, wherein the insoluble component comprises rubber and the PVB raw material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, less than 40 wt%, less than 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt% of the rubber.

[0225] A42. The insoluble components include glass, metal, salt, silicate, calcium, calcium derivatives, sodium derivatives, or a combination thereof, and the PVB raw material contains at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 ... %, at least 4.5%, or at least 5% by weight, and / or less than 50%, less than 40%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1% by weight of glass, metal, salt, silicate, calcium, calcium derivatives, sodium derivatives, or combinations thereof.

[0226] A43. A method for recycling polyvinyl butyral (PVB), comprising: producing a plurality of PVB particles from fresh polyvinyl alcohol (PVOH) and fresh butyraldehyde in the presence of water; partially hydrolyzing a quantity of the PVB particles to produce a reaction product comprising water-insoluble PVB and butyraldehyde, wherein the water-insoluble PVB comprises residual PVOH; and reacting the residual PVOH with additional butyraldehyde to produce regenerated PVB.

[0227] A44. The method of A43, wherein the partial hydrolysis of the PVB particles has a conversion rate of less than 90%, less than 80%, less than 70%, less than 60%, or less than 50%.

[0228] A45. The method according to any of A43 and A44, wherein the partial hydrolysis produces a slurry in water comprising the water-insoluble PVB.

[0229] A46. The method of any of A43 to A45, wherein the partial hydrolysis of the PVB particles produces a slurry containing between 25% and 75% by weight, between 30% and 70% by weight, between 35% and 65% by weight, or between 40% and 60% by weight of water-insoluble PVB.

[0230] A47. The method of any of A43 to A46, wherein the partial hydrolysis of the PVB particles produces a slurry containing more than 25 wt%, more than 50 wt%, more than 75 wt%, between 25 wt% and 75 wt%, between 30 wt% and 70 wt%, between 35 wt% and 65 wt%, or between 40 wt% and 60 wt% water.

[0231] A48. The method according to any one of A43 to A47, wherein the water-insoluble PVB has a higher residual PVOH content than the PVB particles.

[0232] A49. The method according to any one of A43 to A48, wherein the recycled PVB has a lower residual PVOH content than the water-insoluble PVB.

[0233] A50. The method of any of A43 to A49, wherein the partial hydrolysis of the PVB particles produces a water-insoluble PVB having a residual PVOH content of less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, between 20% and 90%, between 30% and 90%, between 40% and 90%, between 50% and 90%, between 50% and 80%, or between 50% and 70%.

[0234] A51. The method of any of A43 to A50, wherein the partial hydrolysis of the PVB particles produces recycled PVB having a residual PVOH content of between 1% and 90%, between 5% and 30%, between 7% and 30%, or between 16% and 20%.

[0235] A52. The method of any of A43 to A51, further comprising reacting the residual PVOH to produce recycled PVB having a target residual PVOH content, wherein the PVB particles have a residual PVOH content that is 1% greater, 2% greater, 3% greater, 4% greater, 5% greater, or 10% greater than the target residual PVOH content.

[0236] A53. The method according to any one of A43 to A52, further comprising reacting the residual PVOH with fresh butyraldehyde to produce recycled PVB.

[0237] A54. The method according to any one of A43 to A53, further comprising carrying out the partial hydrolysis and reaction steps in separate units.

[0238] A55. The method according to any one of A43 to A54, further comprising carrying out the partial hydrolysis and reaction steps in the same unit.

[0239] A56. The method according to any one of A43 to A55, wherein the partial hydrolysis is carried out in the presence of an acid catalyst.

[0240] A57. The method of A56, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0241] A58. The method of any of A56 and A57, further comprising producing the regenerated PVB in the presence of the same acid catalyst as used in the partial hydrolysis step.

[0242] A59. The method according to any one of A43 to A58, wherein the partial hydrolysis is carried out at a temperature within the range of about 70°C to about 250°C.

[0243] A60. The method of any of A56 to A59, wherein the partial hydrolysis is carried out at a temperature in the range of about 70°C to about 150°C when the hydrolysis step occurs in the presence of the acid catalyst.

[0244] A61. The method according to any one of A43 to A55 and A59, wherein the partial hydrolysis is carried out at a temperature in the range of about 150°C to about 250°C if the hydrolysis step does not occur in the presence of the acid catalyst.

[0245] A62. The method according to any one of A43 to A61, wherein the partial hydrolysis is carried out in the presence of an alcohol.

[0246] A63. The method according to any one of A43 to A62, further comprising dissolving the PVB particles in a solvent before the hydrolysis step.

[0247] A64. The method of any of A62 and A63, further comprising dissolving the PVB particles in the solvent comprising the alcohol.

[0248] A65. The method according to any one of A43 to A64, further comprising recovering butyraldehyde produced from the partial hydrolysis of the PVB particles.

[0249] A66. The method according to A65, further comprising producing the recycled PVB from the recovered butyraldehyde.

[0250] A67. The method of any of A43-A66, further comprising inspecting the recycled PVB for at least one of oversizing, visual defects, compositional defects, gelation, or contamination; separating in-spec PVB from substandard PVB based on the inspection; and partially hydrolyzing the substandard PVB to increase the residual PVOH content of the substandard PVB.

[0251] A68. The method of A67, further comprising sizing the off-spec PVB prior to partially hydrolyzing the off-spec PVB.

[0252] A69. The method of either A67 or A68, further comprising sizing said off-spec PVB to an average particle size of less than about 400 microns, less than 300 microns, or less than 200 microns, or between about 200 and about 400 microns.

[0253] Embodiment B1. A method for recycling polyvinyl butyral (PVB) comprising hydrolyzing raw PVB in the presence of hydrogen and a hydrogenation catalyst to produce a solution comprising recycled polyvinyl alcohol (PVOH) and recycled butanol.

[0254] B2. The method of B1, wherein said hydrogenation catalyst comprises at least one Group 8 metal.

[0255] B3. The method of any of B1 and B2, wherein the hydrogenation catalyst is heterogeneous or homogeneous.

[0256] B4. The method of any of B1-B3, wherein the hydrolysis is carried out in at least one of a continuous stirred tank reactor, a bubble column reactor, a fixed bed reactor, a trickle bed reactor, or an autoclave reactor.

[0257] B5. The method of any one of B1 to B4, further comprising recovering at least one of the recycled PVOH, the recycled butanol, and the hydrogenation catalyst from the solution.

[0258] B6. The method of any one of B1-B5, wherein said recovering comprises separating said solution into at least two of a vapor phase, a liquid phase, and a solid phase.

[0259] B7. The method of B6, wherein said recovering recovers said recycled PVOH from said liquid phase.

[0260] B8. The method of any of B6 and B7, wherein said recovering recovers said recycled butanol from at least one of said vapor phase or said liquid phase.

[0261] B9. The method according to any one of B6 to B8, wherein the hydrogenation catalyst is recovered from the solid phase by the recovery.

[0262] B10. The method of any of B1-B9, further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVB.

[0263] B11. The method according to any one of B1 to B10, further comprising cooling the recycled PVOH prior to the reacting step.

[0264] B12. The method of any one of B1 to B11, wherein the hydrolysis is carried out at a pressure in the range of about 10 to about 2000 psia.

[0265] B13. The method according to any one of B1 to B12, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0266] B14. The method of B13, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0267] B15. The method of any of B13 and B14, further comprising producing the regenerated PVB in the presence of the same acid catalyst used in the hydrolysis step.

[0268] B16. The method according to any one of B1 to B15, wherein the hydrolysis is carried out at a temperature within the range of about 70°C to about 250°C.

[0269] B17. The method of any of B13-B16, wherein when the hydrolysis step occurs in the presence of the acid catalyst, the hydrolysis is carried out at a temperature in the range of about 70°C to about 150°C.

[0270] B18. The method of any of B1 to B12 and B16, wherein the hydrolysis is carried out at a temperature in the range of about 150°C to about 250°C if the hydrolysis step does not occur in the presence of an acid catalyst.

[0271] B19. The method according to any one of B1 to B18, wherein the hydrolysis of the PVB raw material is carried out in the presence of an alcohol.

[0272] B20. The method according to any one of B1 to B19, further comprising dissolving the PVB raw material in a solvent before the hydrolysis step.

[0273] B21. The method of any of B19 and B20, further comprising dissolving said PVB raw material in said solvent comprising said alcohol.

[0274] B22. The method of any of B1-B21, further comprising inspecting the recycled PVB for at least one of oversizing, visual defects, compositional defects, gelation, or contamination; separating in-spec PVB from out-of-spec PVB based on the inspection; and hydrolyzing the out-of-spec PVB to produce additional recycled PVOH and recycled butanol.

[0275] B23. The method of B22, further comprising sizing said off-spec PVB prior to hydrolyzing said off-spec PVB.

[0276] B24. The method of any of B22 and B23, further comprising sizing said off-spec PVB to an average particle size of less than about 400 microns, less than 300 microns, or less than 200 microns, or between about 200 and about 400 microns.

[0277] B25. The method of any of B1-B24, further comprising sizing the PVB raw material prior to the hydrolysis step.

[0278] B26. The method of any of B1-B25, further comprising, prior to said hydrolysis step, sizing said PVB raw material to an average particle size of less than about 400 microns, less than 350 microns, less than 300 microns, or less than 250 microns, or between about 200 microns and about 400 microns, between about 225 microns and about 375 microns, or between about 250 microns and about 350 microns.

[0279] B27. The method according to any one of B1 to B26, wherein the PVB raw material contains two or more PVB resins having different compositions.

[0280] B28. The method according to any one of B1 to B27, wherein the PVB raw material comprises two or more PVB resins having different residual PVOH contents.

[0281] B29. The method of any of B1-B28, further comprising extracting a plasticizer from said PVB raw material prior to said hydrolysis of said PVB raw material.

[0282] B30. The method of B29, further comprising extracting plasticizers from said PVB raw material, wherein said PVB raw material is derived from at least one of post-industrial or post-consumer recycled materials.

[0283] B31. The method according to any one of B1 to B30, further comprising washing the PVB raw material to remove insoluble components from the PVB raw material prior to hydrolyzing the PVB raw material.

[0284] B32. The method according to any one of B1 to B31, further comprising centrifuging the solution to remove one or more insoluble components from the solution.

[0285] B33. The method of any of B1-B32, further comprising filtering the solution to remove one or more insoluble components from the solution.

[0286] B34. The method of any of B32 and B33, further comprising centrifuging the solution prior to the filtering step.

[0287] B35. The PVB raw material is at least 8%, at least 9%, at least 9.5%, at least 10%, at least 10.5%, at least 11%, at least 11.5%, at least 12%, at least 12.5%, at least 13%, at least 13.5%, at least 14%, at least 14.5%, at least 15%, at least 15.5%, at least 16%, at least 16.5%, at least 17%, at least 17.5%, at least 18%, at least 18.5, at least 19, at least 19.5, at least 20, at least 25, at least 26, at least 30, the method of any of B1-B34, having a residual PVOH content of at least 32%, at least 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, and / or no more than 100%, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 35% or less, 32% or less, 30% or less, 25% or less, 22% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, or 8% or less.

[0288] B36. The method of any of B1-B35, wherein the PVB stock comprises at least 1, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, or at least 90 phr, based on the total weight of the PVB stock, and / or no more than 100, no more than 90, no more than 85, no more than 80, no more than 75, no more than 70, no more than 65, no more than 60, no more than 55, no more than 50, no more than 45, no more than 40, no more than 35, no more than 30, no more than 25, no more than 20, no more than 15, or no more than 10 phr of plasticizer.

[0289] B37. The method of any of B1-B36, wherein the PVB raw material comprises solid particles having an average particle size of at least 0.01 inches, at least 0.05 inches, at least 0.1 inches, at least 0.2 inches, at least 0.3 inches, at least 0.4 inches, at least 0.5 inches, at least 1 inch, or at least 2 inches.

[0290] B38. The method of any of B1-B37, wherein the PVB raw material contains less than 10% by weight, less than 5% by weight, less than 4% by weight, less than 3% by weight, less than 2% by weight, or less than 1% by weight, or less than 0.5% by weight of solid contaminants, based on the total weight of the PVB raw material.

[0291] B39. The method of any of B1-B38, wherein the PVB raw material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, less than 40 wt%, less than 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt%, based on the total weight of the PVB raw material.

[0292] The method of B39, wherein the insoluble component comprises at least one polymer, the polymer comprising a polyolefin, a polyester, a rubber, a polyamide, a polystyrene, or a combination thereof, and the PVB material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, 40 wt%, 30 wt%, 25 wt%, 20 wt%, 15 wt%, 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, or 1 wt% of the polymer.

[0293] B41. The method of B39, wherein the insoluble component comprises rubber and the PVB raw material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, less than 40 wt%, less than 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt% of the rubber.

[0294] B42. The insoluble components include glass, metal, salt, silicate, calcium, calcium derivatives, sodium derivatives, or a combination thereof, and the PVB raw material has at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 ... %, at least 4.5%, or at least 5% by weight, and / or less than 50%, less than 40%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1% by weight of glass, metal, salt, silicate, calcium, calcium derivatives, sodium derivatives, or combinations thereof.

[0295] B43. A method for recycling polyvinyl butyral (PVB), comprising: producing a plurality of PVB particles from fresh polyvinyl alcohol (PVOH) and fresh butyraldehyde in the presence of water; hydrolyzing a quantity of the PVB particles in the presence of at least one amino-functional compound to produce a solution comprising regenerated PVOH and regenerated butanol; and producing additional PVB particles from the regenerated PVOH in the presence of water.

[0296] B44. The method of B43, wherein the hydrogenation catalyst comprises at least one Group 8 metal.

[0297] B45. The method of any of B43 and B44, wherein the hydrogenation catalyst is heterogeneous or homogeneous.

[0298] B46. The method of any of B43-B45, wherein the hydrolysis is carried out in at least one of a continuous stirred tank reactor, a bubble column reactor, a fixed bed reactor, a trickle bed reactor, or an autoclave reactor.

[0299] B47. The method of any of B43-B46, further comprising recovering at least one of the recycled PVOH, the recycled butanol, and the hydrogenation catalyst from the solution.

[0300] B48. The method of any of B43-B47, wherein said recovering comprises separating said solution into at least two of a vapor phase, a liquid phase, and a solid phase.

[0301] B49. The method of B48, wherein said recovering recovers said recycled PVOH from said liquid phase.

[0302] B50. The method of any of B48 and B49, wherein said recovering recovers said recycled butanol from at least one of said vapor phase or said liquid phase.

[0303] B51. The method according to any one of B48 to B50, wherein the hydrogenation catalyst is recovered from the solid phase by the recovery.

[0304] B52. The method of any of B43-B51, further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVB.

[0305] B53. The method according to any one of B43 to B52, further comprising cooling the recycled PVOH prior to the reacting step.

[0306] B54. The method of any of B43-B53, wherein said hydrolysis is carried out at a pressure in the range of about 10 to about 2000 psia.

[0307] B55. The method according to any one of B43 to B54, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0308] B56. The method of B55, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0309] B57. The method of any of B55 and B56, further comprising producing said regenerated PVB in the presence of the same acid catalyst used in said hydrolysis step.

[0310] B58. The method according to any one of B43 to B57, wherein the hydrolysis is carried out at a temperature within the range of about 100°C to about 250°C.

[0311] B59. The method of any of B43-B58, wherein when said hydrolysis step occurs in the presence of said acid catalyst, said hydrolysis is carried out at a temperature in the range of about 100°C to about 150°C.

[0312] B60. The method of any of B43-B54 and B58, wherein said hydrolysis is carried out at a temperature in the range of about 150°C to about 250°C if said hydrolysis step does not occur in the presence of an acid catalyst.

[0313] B61. The method according to any one of B43 to B60, wherein said hydrolysis of said PVB particles is carried out in the presence of an alcohol.

[0314] B62. The method according to any one of B43 to B61, further comprising dissolving the PVB particles in a solvent before the hydrolysis step.

[0315] B63. The method of any of B61 and B62, further comprising dissolving said PVB particles in said solvent comprising said alcohol.

[0316] B64. The method of any of B43-B63, further comprising inspecting the recycled PVB for at least one of oversizing, visual defects, compositional defects, gelation, or contamination; separating in-spec PVB from out-of-spec PVB based on the inspection; and hydrolyzing the out-of-spec PVB to produce additional recycled PVOH and recycled butanol.

[0317] B65. The method of B64, further comprising sizing said off-spec PVB prior to hydrolyzing said off-spec PVB.

[0318] B66. The method of any of B64 and B65, further comprising sizing said off-spec PVB to an average particle size of less than about 400 microns, less than 300 microns, or less than 200 microns, or between about 200 and about 400 microns.

[0319] Embodiment C1. A method for recycling polyvinyl butyral (PVB) comprising hydrolyzing raw PVB material in the presence of an aldehyde scavenger to produce a solution comprising recycled polyvinyl alcohol (PVOH) and recycled acetal.

[0320] C2. The method of C1, wherein the aldehyde scavenger comprises at least one of a C2 glycol, propanediol, methanol, ethanol, or acetoacetate.

[0321] C3. The method of any of C1 and C2, further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVB.

[0322] C4. The method according to any one of C1 to C3, further comprising cooling the recycled PVOH prior to the reacting step.

[0323] C5. The method of any one of C1 to C4, further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVOH and a first liquid product; and recovering the first liquid product comprising recycled acetal.

[0324] C6. The method of any of C1-C5, further comprising removing at least one of the regenerated PVOH or the aldehyde scavenger from the solution.

[0325] C7. The method according to any one of C1 to C6, wherein the hydrolysis is carried out in the presence of the regenerating solvent.

[0326] C8. The method according to any one of C1 to C7, further comprising precipitating the regenerated PVOH from the solution in the presence of an alcohol.

[0327] C9. The process of C8, wherein recovering the regenerated acetal comprises performing at least one of liquid-liquid extraction or distillation on the second liquid product.

[0328] C10. The method according to any one of C1 to C9, further comprising hydrolyzing the recovered regenerated acetal to produce a regenerated aldehyde.

[0329] C11. The method according to any one of C1 to C10, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0330] C12. The method of C11, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0331] C13. The method of any of C11 and C12, further comprising producing the regenerated PVB in the presence of the same acid catalyst used in the hydrolysis step.

[0332] C14. The method according to any one of C1 to C13, wherein the hydrolysis is carried out at a temperature within the range of about 70°C to about 250°C.

[0333] C15. The method of any of C11 to C14, wherein when the hydrolysis step occurs in the presence of the acid catalyst, the hydrolysis is carried out at a temperature in the range of about 70°C to about 150°C.

[0334] C16. The method of any of C1 to C10 and C14, wherein the hydrolysis is carried out at a temperature in the range of about 150°C to about 250°C if the hydrolysis step does not occur in the presence of an acid catalyst.

[0335] C17. The method according to any one of C1 to C16, wherein the hydrolysis of the PVB raw material is carried out in the presence of an alcohol.

[0336] C18. The method according to any one of C1 to C17, further comprising dissolving the PVB raw material in a solvent before hydrolyzing the PVB raw material.

[0337] C19. The method of any of C17 and C18, further comprising dissolving the PVB raw material in the solvent comprising the alcohol.

[0338] C20. The method of any of C1-C19, further comprising inspecting the recycled PVB for at least one of oversizing, visual defects, compositional defects, gelation, or contamination; separating in-spec PVB from out-of-spec PVB based on the inspection; and hydrolyzing the out-of-spec PVB to produce additional recycled PVOH.

[0339] C21. The method of C20, further comprising sizing the off-spec PVB prior to hydrolyzing the off-spec PVB.

[0340] C22. The method of any of C20 and C21, further comprising sizing the off-spec PVB to an average particle size of less than about 400 microns, less than 300 microns, or less than 200 microns, or between about 200 and about 400 microns.

[0341] C23. The method of any of C1 to C22, further comprising sizing the PVB feedstock prior to the hydrolysis step.

[0342] C24. The method of any of C1-C23, further comprising sizing the PVB feedstock to an average particle size of less than about 400 microns, less than 350 microns, less than 300 microns, or less than 250 microns, or between about 200 microns and about 400 microns, between about 225 microns and about 375 microns, or between about 250 microns and about 350 microns, prior to the hydrolysis step.

[0343] C25. The method according to any one of C1 to C24, wherein the PVB raw material contains two or more PVB resins having different compositions.

[0344] C26. The method according to any one of C1 to C25, wherein the PVB raw material comprises two or more PVB resins having different residual PVOH contents.

[0345] C27. The method of any of C1-C26, further comprising extracting a plasticizer from the PVB raw material prior to said hydrolysis of the PVB raw material.

[0346] C28. The method of C27, further comprising extracting plasticizers from said PVB feedstock, wherein said PVB feedstock material is derived from at least one of post-industrial or post-consumer recycled materials.

[0347] C29. The method of any of C1 to C28, further comprising washing the PVB raw material to remove insoluble components from the PVB raw material prior to hydrolyzing the PVB raw material.

[0348] C30. The method of any of C1-C29, further comprising centrifuging the solution to remove one or more insoluble components from the solution.

[0349] C31. The method of any of C1-C30, further comprising filtering the solution to remove one or more insoluble components from the solution.

[0350] C32. The method of any of C30 and C31, further comprising centrifuging the solution prior to said filtering of the solution.

[0351] C33. The method of any of C1 to C32, further comprising recovering and storing the regenerated PVOH from the solution.

[0352] C34. The PVB raw material has at least 8%, at least 9%, at least 9.5%, at least 10%, at least 10.5%, at least 11%, at least 11.5%, at least 12%, at least 12.5%, at least 13%, at least 13.5%, at least 14%, at least 14.5%, at least 15%, at least 15.5%, at least 16%, at least 16.5%, at least 17%, at least 17.5%, at least 18%, at least 18.5, at least 19%, at least 20%. 5. The method of any of C1-C33, wherein the residual PVOH content is at least 20, at least 25, at least 26, at least 30, at least 32%, at least 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, and / or no more than 100%, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 35% or less, 32% or less, 30% or less, 25% or less, 22% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, or 8% or less.

[0353] C35. The method of any of C1-C34, wherein the PVB stock comprises at least 1, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, or at least 90 phr, based on the total weight of the PVB stock, and / or no more than 100, no more than 90, no more than 85, no more than 80, no more than 75, no more than 70, no more than 65, no more than 60, no more than 55, no more than 50, no more than 45, no more than 40, no more than 35, no more than 30, no more than 25, no more than 20, no more than 15, or no more than 10 phr of plasticizer.

[0354] C36. The method of any of C1-C35, wherein the PVB feedstock comprises solid particles having an average particle size of at least 0.01 inches, at least 0.05 inches, at least 0.1 inches, at least 0.2 inches, at least 0.3 inches, at least 0.4 inches, at least 0.5 inches, at least 1 inch, or at least 2 inches.

[0355] C37. The method of any of C1-C36, wherein the PVB raw material contains less than 10 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt%, or less than 0.5 wt%, solid contaminants, based on the total weight of the PVB raw material.

[0356] C38. The method of any of C1-C37, wherein the PVB raw material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, less than 40 wt%, less than 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt%, based on the total weight of the PVB raw material.

[0357] The method of C38, wherein the insoluble component comprises at least one polymer, the polymer comprising a polyolefin, a polyester, a rubber, a polyamide, a polystyrene, or a combination thereof, and the PVB material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, 40 wt%, 30 wt%, 25 wt%, 20 wt%, 15 wt%, 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, or 1 wt% of the polymer.

[0358] C40. The method of C38, wherein the insoluble component comprises rubber and the PVB raw material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, less than 40 wt%, less than 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt% of the rubber.

[0359] C41. The insoluble components include glass, metal, salt, silicate, calcium, calcium derivatives, sodium derivatives, or a combination thereof, and the PVB raw material contains at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 ... %, at least 4.5%, or at least 5% by weight, and / or less than 50%, less than 40%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1% by weight of glass, metal, salt, silicate, calcium, calcium derivatives, sodium derivatives, or combinations thereof.

[0360] C42. A method for recycling polyvinyl butyral (PVB), comprising: producing a plurality of PVB particles from fresh polyvinyl alcohol and fresh butyraldehyde in the presence of water; hydrolyzing a quantity of the PVB particles in the presence of an aldehyde scavenger to produce a solution containing regenerated PVOH; and producing additional PVB particles from the regenerated PVOH in the presence of water.

[0361] C43. The method of C42, wherein the aldehyde scavenger comprises at least one of a C2 glycol, propanediol, methanol, ethanol, or acetoacetate.

[0362] C44. The process of any of C42 and C43, further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVB.

[0363] C45. The method of any of C42 to C44, further comprising cooling the recycled PVOH prior to the reacting step.

[0364] C46. The method of any of C42 to C45, further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVOH and a first liquid product; and recovering the first liquid product comprising the recycled acetal.

[0365] C47. The method of any of C42-C46, further comprising removing at least one of the regenerated PVOH or the aldehyde scavenger from the solution.

[0366] C48. The method according to any one of C42 to C47, wherein the hydrolysis is carried out in the presence of the regenerating solvent.

[0367] C49. The method of any of C42 to C48, further comprising precipitating the regenerated PVOH from the solution in the presence of an alcohol.

[0368] C50. The process of C49, wherein recovering the regenerated acetal comprises performing at least one of liquid-liquid extraction or distillation on the second liquid product.

[0369] C51. The method of any of C42 to C50, further comprising hydrolyzing the recovered regenerated acetal to produce a regenerated aldehyde.

[0370] C52. The method according to any one of C42 to C51, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0371] C53. The method of C52, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0372] C54. The method of any of C52 and C53, further comprising producing the recycled PVB in the presence of the same acid catalyst used in the hydrolysis step of the PVB particles.

[0373] C55. The method of any of C42 to C54, wherein the hydrolysis is carried out at a temperature in the range of about 70°C to about 250°C.

[0374] C56. The method of any of C52 to C55, wherein when the hydrolysis step occurs in the presence of the acid catalyst, the hydrolysis is carried out at a temperature in the range of about 70°C to about 150°C.

[0375] C57. The method of any of C42 to C51 and C55, wherein the hydrolysis is carried out at a temperature in the range of about 150°C to about 250°C if the hydrolysis step does not occur in the presence of an acid catalyst.

[0376] C58. The method of any of C42 to C57, wherein the hydrolysis of the PVB particles is carried out in the presence of an alcohol.

[0377] C59. The method according to any one of C42 to C58, further comprising dissolving the PVB particles in a solvent prior to the hydrolysis step.

[0378] C60. The method of any of C58 and C59, further comprising dissolving the PVB particles in the solvent comprising the alcohol.

[0379] C61. The method of any of C42-C60, further comprising inspecting the recycled PVB for at least one of oversizing, visual defects, compositional defects, gelation, or contamination; separating in-spec PVB from out-of-spec PVB based on the inspection; and hydrolyzing the out-of-spec PVB to produce additional recycled PVOH.

[0380] C62. The method of C61, further comprising sizing the off-spec PVB prior to hydrolyzing the off-spec PVB.

[0381] C63. The method of any of C61 and C62, further comprising sizing the off-spec PVB to an average particle size of less than about 400 microns, less than 300 microns, or less than 200 microns, or between about 200 and about 400 microns.

[0382] C64. The method of any of C42 to C63, further comprising recovering and storing the regenerated PVOH from the solution.

[0383] Embodiment D1. A method for recycling polyvinyl butyral (PVB), comprising hydrolyzing raw PVB material in the presence of at least one amino-functional compound to produce a solution comprising recycled polyvinyl alcohol (PVOH) and one or more butylimine derivatives.

[0384] D2. The method of D1, wherein the at least one amino-functional compound comprises at least one of a monofunctional amine, a difunctional amine, an aromatic amine, ethanolamine, methylamine, ethylamine, ethyldiamine, propyldiamine, butylamine, or ammonia.

[0385] D3. The method of any of D1 and D2, further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVB.

[0386] D4. The method according to any one of D1 to D3, further comprising cooling the recycled PVOH prior to the reacting step.

[0387] D5. The method of any of D1-D4, further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVOH and a first liquid product; and recovering the first liquid product comprising the one or more butylimine derivatives.

[0388] D6. The method of any one of D1 to D5, further comprising precipitating the regenerated PVOH from the solution in the presence of an alcohol.

[0389] D7. The method of any of D1-D6, further comprising recovering a second liquid product separated from the precipitated PVOH; and recovering the one or more butylimine derivatives from the second liquid product.

[0390] D8. The method of D7, wherein recovering the one or more butylimine derivatives comprises performing at least one of liquid-liquid extraction or distillation on the second liquid product.

[0391] D9. The method according to any one of D1 to D8, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0392] D10. The method of D9, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0393] D11. The method of any of D9 and D10, further comprising producing the recycled PVB in the presence of the same acid catalyst used in the hydrolysis of the raw PVB material.

[0394] D12. The method according to any one of D1 to D11, wherein the hydrolysis is carried out at a temperature within the range of about 70°C to about 250°C.

[0395] D13. The method of any of D9-D12, wherein when the hydrolysis step occurs in the presence of the acid catalyst, the hydrolysis is carried out at a temperature in the range of about 70°C to about 150°C.

[0396] D14. The method of any of D1 to D8 and D12, wherein the hydrolysis is carried out at a temperature in the range of about 150°C to about 250°C if the hydrolysis step does not occur in the presence of an acid catalyst.

[0397] D15. The method according to any one of D1 to D14, wherein the hydrolysis of the PVB raw material is carried out in the presence of an alcohol.

[0398] D16. The method according to any one of D1 to D15, further comprising dissolving the PVB raw material in a solvent before the hydrolysis step.

[0399] D17. The method of any of D14 and D15, further comprising dissolving the PVB raw material in the solvent comprising the alcohol.

[0400] D18. The method of any of D1-D17, further comprising inspecting the recycled PVB for at least one of oversizing, visual defects, compositional defects, gelation, or contamination; separating in-spec PVB from out-of-spec PVB based on the inspection; and hydrolyzing the out-of-spec PVB to produce additional recycled PVOH.

[0401] D19. The method of D18, further comprising sizing the off-spec PVB prior to hydrolyzing the off-spec PVB.

[0402] D20. The method of any of D18 and D19, further comprising sizing the off-spec PVB to an average particle size of less than about 400 microns, less than 300 microns, or less than 200 microns, or between about 200 and about 400 microns.

[0403] D21. The method of any of D1-D20, further comprising sizing the PVB feedstock prior to the hydrolysis step.

[0404] D22. The method of any of D1-D21, further comprising sizing the PVB feedstock to an average particle size of less than about 400 microns, less than 350 microns, less than 300 microns, or less than 250 microns, or between about 200 microns and about 400 microns, between about 225 microns and about 375 microns, or between about 250 microns and about 350 microns, prior to the hydrolysis step.

[0405] D23. The method according to any one of D1 to D22, wherein the PVB raw material comprises two or more PVB resins having different compositions.

[0406] D24. The method of any of D1-D23, wherein the PVB raw material comprises two or more PVB resins having different residual PVOH contents.

[0407] D25. The method of any of D1-D24, further comprising extracting a plasticizer from the PVB raw material prior to said hydrolysis of the PVB raw material.

[0408] D26. The method of D25, further comprising extracting plasticizers from said PVB raw material, wherein said PVB raw material is derived from at least one of post-industrial or post-consumer recycled materials.

[0409] D27. The method of any of D1-D26, further comprising washing the PVB raw material to remove insoluble components from the PVB raw material prior to hydrolyzing the PVB raw material.

[0410] D28. The method according to any one of D1 to D27, further comprising centrifuging the solution to remove one or more insoluble components from the solution.

[0411] D29. The method of any of D1-D28, further comprising filtering the solution to remove one or more insoluble components from the solution.

[0412] D30. The method of any of D28 and D29, further comprising centrifuging the solution prior to the filtering step.

[0413] D31. The method of any of D1-D30, further comprising recovering and storing the regenerated PVOH from the solution.

[0414] D32. The PVB raw material is at least 8%, at least 9%, at least 9.5%, at least 10%, at least 10.5%, at least 11%, at least 11.5%, at least 12%, at least 12.5%, at least 13%, at least 13.5%, at least 14%, at least 14.5%, at least 15%, at least 15.5%, at least 16%, at least 16.5%, at least 17%, at least 17.5%, at least 18%, at least 18.5, at least 19%, at least 20%. 5. The method of any of D1-D31, wherein the residual PVOH content is at least 20, at least 25, at least 26, at least 30, at least 32%, at least 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, and / or no more than 100%, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 35% or less, 32% or less, 30% or less, 25% or less, 22% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, or 8% or less.

[0415] D33. The method of any of D1-D32, wherein the PVB stock comprises at least 1, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, or at least 90 phr, based on the total weight of the PVB stock, and / or no more than 100, no more than 90, no more than 85, no more than 80, no more than 75, no more than 70, no more than 65, no more than 60, no more than 55, no more than 50, no more than 45, no more than 40, no more than 35, no more than 30, no more than 25, no more than 20, no more than 15, or no more than 10 phr of plasticizer.

[0416] D34. The method of any of D1-D33, wherein the PVB raw material comprises solid particles having an average particle size of at least 0.01 inches, at least 0.05 inches, at least 0.1 inches, at least 0.2 inches, at least 0.3 inches, at least 0.4 inches, at least 0.5 inches, at least 1 inch, or at least 2 inches.

[0417] D35. The method of any of D1-D34, wherein the PVB raw material contains less than 10 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt%, or less than 0.5 wt%, solid contaminants, based on the total weight of the PVB raw material.

[0418] D36. The method of any of D1-D35, wherein the PVB raw material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, less than 40 wt%, less than 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt%, based on the total weight of the PVB raw material.

[0419] The method of D36, wherein the insoluble component comprises at least one polymer, the polymer comprising a polyolefin, a polyester, a rubber, a polyamide, a polystyrene, or a combination thereof, and the PVB material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, 40 wt%, 30 wt%, 25 wt%, 20 wt%, 15 wt%, 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, or 1 wt% of the polymer.

[0420] D38. The method of D36, wherein the insoluble component comprises rubber and the PVB raw material comprises at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.5 wt%, or at least 5 wt%, and / or less than 50 wt%, less than 40 wt%, less than 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt% of the rubber.

[0421] D39. The insoluble components include glass, metal, salt, silicate, calcium, calcium derivatives, sodium derivatives, or a combination thereof, and the PVB raw material contains at least 0.01 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 ... %, at least 4.5%, or at least 5% by weight, and / or less than 50%, less than 40%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1% by weight of glass, metal, salt, silicate, calcium, calcium derivatives, sodium derivatives, or combinations thereof.

[0422] D40. A method for recycling polyvinyl butyral (PVB), comprising: producing a plurality of PVB particles from fresh polyvinyl alcohol and fresh butyraldehyde in the presence of water; hydrolyzing a quantity of the PVB particles in the presence of at least one amino-functional compound to produce a solution comprising regenerated PVOH and one or more butylimine derivatives; and producing additional PVB particles from the regenerated PVOH in the presence of water.

[0423] D41. The method of D40, wherein said at least one amino-functional compound comprises at least one of a monofunctional amine, a difunctional amine, an aromatic amine, ethanolamine, methylamine, ethylamine, ethyldiamine, propyldiamine, butylamine, or ammonia.

[0424] D42. The method of any of D40 and D41, further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVB.

[0425] D43. The method according to any one of D40 to D42, further comprising cooling the recycled PVOH prior to the reacting step.

[0426] D44. The method of any of D40-D43, further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVOH and a first liquid product; and recovering the first liquid product comprising the one or more butylimine derivatives.

[0427] D45. The method of any of D40-D44, further comprising precipitating the regenerated PVOH from the solution in the presence of an alcohol.

[0428] D46. The method of any of D40-D45, further comprising recovering a second liquid product separated from the precipitated PVOH; and recovering the one or more butylimine derivatives from the second liquid product.

[0429] D47. The method of D46, wherein recovering the one or more butylimine derivatives comprises performing at least one of liquid-liquid extraction or distillation on the second liquid product.

[0430] D48. The method according to any one of D40 to D47, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0431] D49. The method of D48, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0432] D50. The method of any of C48 and C49, further comprising producing the regenerated PVB in the presence of the same acid catalyst used in the hydrolysis of the PVB particles.

[0433] D51. The method according to any one of D40 to D50, wherein the hydrolysis is carried out at a temperature in the range of about 70°C to about 250°C.

[0434] D52. The method of any of D48-D51, wherein when the hydrolysis step occurs in the presence of the acid catalyst, the hydrolysis is carried out at a temperature in the range of about 70°C to about 150°C.

[0435] D53. The method according to any one of D40 to D47 and D51, wherein the hydrolysis is carried out at a temperature in the range of about 150°C to about 250°C if the hydrolysis step does not occur in the presence of an acid catalyst.

[0436] D54. The method according to any of D40 to D53, wherein the hydrolysis of the PVB particles is carried out in the presence of an alcohol.

[0437] D55. The method according to any of D40 to D54, further comprising dissolving the PVB particles in a solvent prior to the hydrolysis step.

[0438] D56. The method of any of D54 and D55, further comprising dissolving said PVB particles in said solvent comprising said alcohol.

[0439] D57. The method of any of D40-D56, further comprising inspecting the recycled PVB for at least one of oversizing, visual defects, compositional defects, gelation, or contamination; separating in-spec PVB from out-of-spec PVB based on the inspection; and hydrolyzing the out-of-spec PVB to produce additional recycled PVOH.

[0440] D58. The method of D57, further comprising sizing the off-spec PVB prior to hydrolyzing the off-spec PVB.

[0441] D59. The method of any of D57 and D58, further comprising sizing the off-spec PVB to an average particle size of less than about 400 microns, less than 300 microns, or less than 200 microns, or between about 200 and about 400 microns.

[0442] D60. The method of any of D40-D59, further comprising recovering and storing the regenerated PVOH from the solution.

[0443] Additional advantages of various embodiments will be apparent to those skilled in the art upon reviewing the disclosure herein. It will be understood that the various embodiments described herein are not necessarily mutually exclusive, unless otherwise indicated herein. For example, features described or illustrated in one embodiment may, but are not necessarily, included in other embodiments. Thus, the present disclosure encompasses various combinations and / or integrations of the specific embodiments described herein.

[0444] Example 1: A 3 liter Parr reactor was charged with 15 parts of PVB resin containing 18.7% PVOH, 0.25 parts of EDTA, and 1000 parts of water while stirring at 300 rpm. The mixture was heated to 200°C and held for 6 hours. The resulting clear solution was cooled to room temperature and determined to contain 0.94% total solids.

[0445] Example 2: A 1-liter, three-necked, jacketed glass reactor was stirred at 300 rpm and charged with 10 parts of PVB resin containing 18.7% PVOH, 1000 parts of water, and 14.2 parts of 70% by weight nitric acid. The mixture was heated to 85°C and held for 6 hours. The resulting suspension was cooled to room temperature and neutralized to pH 7 with 8.83 parts of KOH. After filtration and drying, 8 parts of PVB resin with 47% PVOH was obtained.

[0446] Example 3: A 1-liter, three-necked, jacketed glass reactor was charged with 40 parts of PVB resin containing 18.7% PVOH, 1000 parts of water, and 14.2 parts of 70% by weight nitric acid while stirring at 300 rpm. The mixture was heated to 90°C and held for 6 hours. The resulting suspension was cooled to room temperature and neutralized to pH 7 with 8.83 parts of KOH. After filtration and drying, 36 parts of PVB resin with 35.1% PVOH was obtained.

[0447] Example 4: A 1-liter, three-necked, jacketed glass reactor was charged with 10 parts of PVB resin containing 18.7% PVOH, 1000 parts of water, and 14.2 parts of 70% by weight nitric acid while stirring at 300 rpm. The mixture was heated to 85°C and held for 12.5 hours. The resulting clear solution was cooled to room temperature and neutralized to pH 7 with 8.83 parts of KOH. The solution was placed in an aluminum tray and dried in an oven at 45°C for 2 days to yield a film. The film was washed with water to remove salts and yield 7 parts of dry PVOH.

[0448] Example 5: A 1-liter, three-necked, jacketed glass reactor was charged with 20 parts of PVB resin containing 18.7% PVOH, 1000 parts of water, 0.16 parts of EDTA, and 14.2 parts of 70% by weight nitric acid while stirring at 300 rpm. The mixture was heated to 80°C and held for 26 hours. The resulting clear solution was cooled to room temperature and neutralized to pH 7 with 8.83 parts of KOH. The solution was placed in an aluminum tray in an oven at 45°C for 2 days to obtain a film. The film was washed with water to remove salts, yielding 13 parts of dry PVOH.

[0449] Example 6: A 1-liter, three-necked, jacketed glass reactor was charged with 40 parts of PVB resin containing 18.7% PVOH, 1000 parts of water, 0.16 parts of EDTA, and 14.2 parts of 70% by weight nitric acid while stirring at 300 rpm. The mixture was heated to 90°C and held for 26 hours. The resulting clear solution was cooled to room temperature and neutralized to pH 7 with 8.83 parts of KOH. The solution was placed in an aluminum tray in an oven at 45°C for 2 days to obtain a film. The film was washed with water to remove salts, yielding 25 parts of dry PVOH.

[0450] Example 7: A 1-liter, three-necked, jacketed glass reactor was charged with 2 parts of 10.5% PVOH PVB resin, 1000 parts of water, 0.16 parts of EDTA, and 14.2 parts of 70% by weight nitric acid while stirring at 300 rpm. The mixture was heated to 80°C and held for 40 hours. The resulting clear solution was cooled to room temperature and neutralized to pH 7 with 8.83 parts of KOH. The solution was placed in an aluminum tray in an oven at 45°C for 2 days to obtain a film. The film was washed with water to remove salts, yielding 1.4 parts of dry PVOH.

[0451] Example 8: 200 parts of recycled PVB interlayer flakes (10 x 10 mm) and 1,000 parts of water were added to a 1-liter, three-necked, jacketed glass reactor. The pH of the mixture was adjusted to between 1.5 and 2 with dilute sulfuric acid. The mixture was heated to 50°C and held with stirring for 1 hour. The resulting slurry was filtered, washed, and then air-dried.

[0452] Example 9: A mixture of 500 parts alcohol (91% ethanol and 9% water) and 200 parts deionized water was charged into a 1-liter, three-neck jacketed glass reactor. To this stirred mixture, 100 parts of the PVB flakes from the previous example were added and stirred at room temperature (22°C) for 4 hours. The resulting mixture was then filtered, and the above process was repeated five more times using the filtered polymer flakes to obtain 65 parts of dried PVB resin flakes. 45 parts of these PVB resin flakes and 1000 parts alcohol (91% ethanol and 9% water) were charged into a 1-liter, three-neck jacketed glass reactor. The mixture was heated to 70°C with stirring at 200 rpm and held for 2 hours. The dissolved mixture had a total solids content of 4.3% and was used in the following examples.

[0453] Example 10: A 1-liter, three-necked, jacketed glass reactor was charged with 1000 parts water, 0.16 parts EDTA, and 14.2 parts 70 wt. % nitric acid while stirring at 300 rpm. The mixture was heated to 80°C, and 200 parts of the solution from Example 9 were added to the mixture over 2 hours. The mixture was then held at 80°C for 22 hours with stirring at 400 rpm until the suspended polymer was dissolved. The resulting solution was hot filtered under pressure using a 1-micron retention ErtelAlsop M-503p filter to obtain a clear solution, which was cooled to room temperature and neutralized to pH 7 with 8.83 parts KOH. The solution was placed in an aluminum tray in a 45°C oven for 2 days to obtain a film. The film was washed with water to remove any salts, yielding 6 parts dry PVOH.

[0454] definition It should be understood that the following is not intended to be an exhaustive list of defined terms. Other definitions may be provided in the preceding description, for example, when accompanying the use of a defined term in context.

[0455] As used herein, the terms "a," "an," and "the" mean one or more.

[0456] As used herein, the term "and / or," when used in a list of two or more items, means that any one of the listed items may be employed alone, or any combination of two or more of the listed items may be employed. For example, if a composition is described as containing components A, B, and / or C, the composition can contain A only, B only, C only, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B, and C.

[0457] As used herein, the phrase "at least a portion" includes at least a portion, and up to and including the entire amount or period of time.

[0458] As used herein, the term "chemical recycling" refers to a PVB recycling process that involves chemically converting waste PVB into lower molecular weight polymers, oligomers, monomers, and / or non-polymer molecules (e.g., carbon monoxide, C2-C4 aldehydes, ethylene, and propylene) that are useful in their own right and / or as feedstocks for another chemical manufacturing process(es).

[0459] As used herein, the terms "comprising," "comprises," and "comprise" are open-ended transitional phrases used to transition the subject matter listed before the term to one or more elements listed after the term, and the element(s) listed after the transitional phrase are not necessarily the only elements that make up the subject matter.

[0460] As used herein, the term "directly derived" refers to having at least one physical component derived from recycled PVB.

[0461] As used herein, the terms "having," "has," and "have" have the same open-ended meaning as "comprising," "comprises," and "comprise" above.

[0462] As used herein, "including," "include," and "included" have the same open-ended meaning as "comprising," "comprises," and "comprise" above.

[0463] As used herein, the term "interlayer" refers to a single or multi-layer polymer sheet suitable for use with at least one rigid substrate to form a multi-layer panel.

[0464] As used herein, the term "isolated" refers to the characteristic of an object or objects being by themselves or themselves, in motion or at rest, and separated from other matter.

[0465] As used herein, the term "pretreatment" refers to preparing a PVB composition for chemical recycling using one or more of the following steps: (i) grinding, (ii) micronization, (iii) washing, (iv) drying, and / or (v) separation.

[0466] As used herein, the terms "recycled content" and "recycled" refer to a composition that is or includes a composition that is directly and / or indirectly derived from recycled / waste PVB compositions.

[0467] As used herein, the terms "single-sheet" interlayer and "integral" interlayer refer to an interlayer formed from one resin sheet, while the terms "multi-layer" interlayer and "multi-layer" interlayer refer to an interlayer in which two or more resin sheets are coextruded, laminated, or otherwise bonded together.

[0468] Numeric range The description of the present invention uses numerical ranges to quantify certain parameters related to the present invention. When a numerical range is presented, it should be understood that such range should be construed as providing literal support for any claim limitation that recites only the lower limit of the range, as well as for any claim limitation that recites only the upper limit of the range. For example, a disclosed numerical range of 10 to 100 provides literal support for a claim that recites "greater than 10" (without an upper limit) and a claim that recites "less than 100" (without a lower limit).

[0469] Additionally, it should be understood that a list of values ​​following a descriptor such as "at least" and "not greater than" literally supports a range based on all the values ​​following that descriptor. For example, a statement specifying "at least 2, 5, 10, and / or no greater than 100, 50, or 25" would literally support the ranges "at least 25," "no greater than 50," and "at least 10 to no greater than 25."

[0470] Claims not limited to the disclosed embodiments The preferred embodiments of the present invention described above are merely used as an illustration and should not be used to limit the scope of the present invention. Modifications to the exemplary embodiments shown above can be easily made by those skilled in the art without departing from the spirit of the present invention.

[0471] The inventors hereby express their intention to rely on the doctrine of equivalents to determine and assess the reasonably fair scope of the present invention for devices that do not materially depart from, but fall outside, the literal scope of the present invention as set forth in the following claims.

Claims

1. 1. A method for recycling polyvinyl butyral (PVB), comprising hydrolyzing or partially hydrolyzing a PVB feedstock to produce a solution comprising recycled polyvinyl alcohol (PVOH) derived from the PVB feedstock.

2. 10. The method of claim 1, wherein the hydrolysis or partial hydrolysis does not occur in the presence of a catalyst.

3. 3. The method of claim 2, wherein the hydrolysis or partial hydrolysis does not occur in the presence of a catalyst and is carried out at a temperature within the range of about 150°C to about 250°C.

4. The method of claim 1 , wherein the hydrolysis or partial hydrolysis occurs in the presence of an acid catalyst.

5. 5. The method of claim 4, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

6. 5. The method of claim 4, wherein the hydrolysis or partial hydrolysis is carried out in the presence of one or more of an acid catalyst or a co-catalyst that forms an unstable hydrolyzable molecule.

7. 7. The method of claim 5 or 6, wherein the hydrolysis or partial hydrolysis is carried out in the presence of an acid catalyst and at a temperature in the range of about 70°C to about 150°C.

8. The method of any one of claims 1 to 7, wherein the PVB feedstock is hydrolyzed to PVOH at a conversion of at least 90%.

9. 8. The method of any one of claims 1 to 7, wherein the PVB feedstock is partially hydrolyzed to a conversion of less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, between 20% and 90%, between 30% and 90%, between 40% and 90%, between 50% and 90%, between 50% and 80%, or between 50% and 70%.

10. 10. The method of any of claims 1 to 7 and 9, wherein the partial hydrolysis of the PVB raw material produces a slurry containing between 25% and 75% by weight, between 30% and 70% by weight, between 35% and 65% by weight, or between 40% and 60% by weight of water-insoluble PVB.

11. 10. The method of any of claims 1 to 7 and 9, wherein the partial hydrolysis of the PVB feedstock produces a slurry containing about 75% to about 99% water by weight, or 80% to 98% water by weight.

12. The method of any one of claims 1 to 11, further comprising cooling the recycled PVOH prior to the reacting step.

13. The method of any of claims 1 to 12, further comprising centrifuging the solution to remove one or more insoluble components from the solution prior to the filtering step.

14. The method of any one of claims 1 to 13, wherein the PVB raw material is derived from at least one of post-industrial recycled material or post-consumer recycled material.

15. The PVB raw material is at least 8%, at least 9%, at least 9.5%, at least 10%, at least 10.5%, at least 11%, at least 11.5%, at least 12%, at least 12.5%, at least 13%, at least 13.5%, at least 14%, at least 14.5%, at least 15%, at least 15.5%, at least 16%, at least 16.5%, at least 17%, at least 17.5%, at least 18%, at least 18.5%, at least 19%, at least 19.5%, at least 20%, at least 25%, at least 26%, at least 30%, at least 32%, at least 34%, at least 36%, at least 38%, at least 39%, at least 40%, at least 41%, at least 42%, at least 43%, at least 44%, at least 45%, at least 46%, at least 47%, at least 48%, at least 49%, at least 50%, at least 51%, at least 52%, at least 53%, at least 54%, at least 55%, at least 56%, at least 57%, at least 58%, at least 59%, at least 60%, at least 61%, at least 62%, at least 63%, at least 64%, at least 65%, at least 66%, at least 67%, at least 68%, at least 69%, at least 70%, at least 71%, at least 72%, at least 73%, at least 74%, at least 75%, at least 76%, at least 77%, at least 78%, at least 79%, at least 80%, at least 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88 15. The method of any of claims 1 to 14, having a residual PVOH content of 0%, at least 32%, at least 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, and / or no more than 100%, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 35% or less, 32% or less, 30% or less, 25% or less, 22% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, or 8% or less.

16. The method according to any one of claims 1 to 15, wherein the PVB raw material comprises two or more PVB resins having different compositions.

17. The method of any one of claims 1 to 16, wherein the PVB raw material comprises two or more PVB resins having different residual PVOH contents.

18. 18. The method of any one of claims 1 to 17, wherein the PVB stock comprises at least 1, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, or at least 90 phr, based on the total weight of the PVB stock, and / or no more than 100, no more than 90, no more than 85, no more than 80, no more than 75, no more than 70, no more than 65, no more than 60, no more than 55, no more than 50, no more than 45, no more than 40, no more than 35, no more than 30, no more than 25, no more than 20, no more than 15, or no more than 10 phr of plasticizer.

19. The method of any preceding claim, further comprising extracting plasticizer from the PVB raw material.

20. 20. The method of any of claims 1 to 19, further comprising sizing the PVB feedstock to an average particle size of less than about 400 microns, less than 350 microns, less than 300 microns, or less than 250 microns, or between about 200 microns and about 400 microns, between about 225 microns and about 375 microns, or between about 250 microns and about 350 microns, prior to the hydrolysis step.

21. 21. The method of any of claims 1-20, further comprising reacting the residual PVOH with butyraldehyde to produce the recycled PVB having a residual PVOH content of between 1% and 90%, between 5% and up to 30%, between 7% and 30%, or between 16% and 20%.

22. 22. The method of any of claims 1-21, further comprising reacting the residual PVOH with butyraldehyde to produce recycled PVB having a target residual PVOH content, wherein the PVB feedstock has a residual PVOH content that is 1% greater, 2% greater, 3% greater, 4% greater, 5% greater, or 10% greater than the target residual PVOH content.

23. 23. The method of any one of claims 1 to 22, further comprising recovering butyraldehyde produced in the hydrolysis step.

24. 24. The method of any one of claims 1 to 23, further comprising reacting the residual PVOH with butyraldehyde recovered from the hydrolysis step to produce recycled PVB.

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