Method for recovering polyvinyl butyral

Abstract

A process for converting polyvinyl butyral (PVB) into its original components (e.g., polyvinyl alcohol (PVOH) and butyraldehyde) by hydrolysis. The process facilitates hydrolysis of a PVB feed composition into its original components, which can be derived from recycled component materials. The regenerated PVOH recovered from the process, PVB having a higher residual PVOH content, and / or butyraldehyde can then be used to produce purified and / or regenerated PVB.

Description

Background Art

[0001] Waste materials, especially non - biodegradable waste materials, can have a negative impact on the environment when disposed of in landfills after single - use. Therefore, from an environmental perspective, it is necessary to recycle as much waste as possible. However, from an economic perspective, recycling waste materials can be challenging. To maximize recycling efficiency, large - scale production facilities are needed to process raw materials with recycled components from various waste sources. Commercial facilities involved in the production of non - biodegradable products or products with a final destination in landfills can greatly benefit from using raw materials with recycled components.

[0002] Polyvinyl butyral (PVB) is commonly used in the manufacture of polymer sheets, which can be used as interlayers in multilayer boards (including, for example, light - transmissive laminates such as safety glass or polymer laminates). PVB is also used in photovoltaic solar panels to encapsulate the panels for power generation and supply for commercial and residential applications. PVB waste from the production and / or disposal sources of such PVB products is generally not suitable for recycling into other products without intervention treatment. For example, one or more of additives, adhesives, plasticizers, etc. can be present in PVB waste. Such additives usually have to be removed from PVB waste to recycle PVB.

[0003] Therefore, there is a need to develop methods for effectively recycling low - quality PVB or PVB waste to produce recycled - component polymer materials. Summary of the Invention

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

[0005] A method for recycling polyvinyl butyral (PVB) is also provided herein. The method includes producing a plurality of PVB particles from fresh polyvinyl alcohol and fresh butyral in the presence of water, hydrolyzing a certain amount of the PVB particles to produce a solution containing r - PVOH, and producing additional PVB particles from the r - PVOH in the presence of water. Brief Description of the Drawings

[0006] Figure 1 is a schematic diagram of an exemplary method for recycling polyvinyl butyral.

[0007] Figure 2 is a schematic diagram of an alternative method for recycling polyvinyl butyral.

[0008] Figure 3 is a schematic diagram of an exemplary method for producing and recycling polyvinyl butyral.

[0009] Figure 4 It is a schematic diagram of an alternative method for producing and recycling polyvinyl butyral.

[0010] Figure 5 It is a schematic diagram of an exemplary method for recycling polyvinyl butyral by partial hydrolysis.

[0011] Figure 6 It is a schematic diagram of an alternative method for recycling polyvinyl butyral by partial hydrolysis.

[0012] Figure 7 It is a schematic diagram of an alternative method for recycling polyvinyl butyral by partial hydrolysis.

[0013] Figure 8 It is a schematic diagram of an exemplary method for producing and recycling polyvinyl butyral by partial hydrolysis.

[0014] Figure 9 It is a schematic diagram of an exemplary method for producing and recycling polyvinyl butyral by partial hydrolysis.

[0015] Figure 10 It is a schematic diagram of an exemplary method for producing and recycling polyvinyl butyral by partial hydrolysis.

[0016] Figure 11 It is a schematic diagram of an exemplary method for recycling polyvinyl butyral using alcohol-based aldehyde scavenging.

[0017] Figure 12 It is a schematic diagram of an alternative method for recycling polyvinyl butyral using alcohol-based aldehyde scavenging.

[0018] Figure 13 It is a schematic diagram of an exemplary method for recycling polyvinyl butyral using amine-based aldehyde scavenging.

[0019] Figure 14 It is a schematic diagram of an alternative method for recycling polyvinyl butyral using amine-based aldehyde scavenging.

[0020] Figure 15 It is a schematic diagram of an exemplary method for recycling polyvinyl butyral by hydrogenation. Detailed Description

[0021] Also provided herein is a method for recycling polyvinyl butyral (PVB). The method includes partially hydrolyzing a PVB feedstock to produce a reaction product comprising unreacted PVB and butyraldehyde, wherein the unreacted PVB comprises residual polyvinyl alcohol (PVOH). The method further includes reacting the residual PVOH with additional butyraldehyde to produce regenerated PVB.

[0022] The present invention also provides a method for recovering polyvinyl butyral (PVB). The method includes producing various PVB particles from fresh polyvinyl alcohol (PVOH) and fresh butyraldehyde in the presence of water, partially hydrolyzing a certain amount of the PVB particles to produce a reaction product containing unreacted PVB and butyraldehyde, wherein the unreacted PVB contains residual PVOH, and reacting the residual PVOH with additional butyraldehyde to produce recycled PVB.

[0023] The present invention provides a method for recovering polyvinyl butyral (PVB). The method includes hydrolyzing a PVB feedstock in the presence of hydrogen and a hydrogenation catalyst to produce a solution containing recycled polyvinyl alcohol (PVOH) and recycled butanol.

[0024] The present invention also provides a method for recovering polyvinyl butyral (PVB). The method includes producing various PVB particles from fresh polyvinyl alcohol (PVOH) and fresh butyraldehyde in the presence of water; hydrolyzing a certain amount of the PVB particles in the presence of at least one amino-functional compound to produce a solution containing recycled PVOH and recycled butanol; and producing additional PVB particles from the recycled PVOH in the presence of water.

[0025] The present invention provides a method for recovering polyvinyl butyral (PVB). The method hydrolyzes a PVB feedstock in the presence of an aldehyde scavenger to produce a solution containing recycled polyvinyl alcohol (PVOH) and recycled acetal.

[0026] The present invention also provides a method for recovering polyvinyl butyral (PVB). The method includes producing various PVB particles from fresh polyvinyl alcohol and fresh butyraldehyde in the presence of water, hydrolyzing a certain amount of the PVB particles in the presence of an aldehyde scavenger to produce a solution containing recycled PVOH, and producing additional PVB particles from the recycled PVOH in the presence of water.

[0027] The present invention provides a method for recovering polyvinyl butyral (PVB). The method includes hydrolyzing a PVB feedstock in the presence of at least one amino-functional compound to produce a solution containing recycled polyvinyl alcohol (PVOH) and one or more butylimine derivatives.

[0028] The present invention also provides a method for recovering polyvinyl butyral (PVB). The method includes producing various PVB particles from fresh polyvinyl alcohol and fresh butyraldehyde in the presence of water, hydrolyzing a certain amount of the PVB particles in the presence of at least one amino-functional compound to produce a solution containing recycled PVOH and one or more butylimine derivatives, and producing additional PVB particles from the recycled PVOH in the presence of water.

[0029] What is implemented is:

[0030] E1. A method for recovering polyvinyl butyral (PVB), the method comprising: hydrolyzing or partially hydrolyzing a PVB raw material to produce a solution comprising regenerated polyvinyl alcohol (PVOH) derived from the PVB raw material.

[0031] E2. The method according to embodiment E1, wherein the hydrolysis or partial hydrolysis occurs in the absence of a catalyst.

[0032] E3. The method according to embodiment E2, wherein the hydrolysis or partial hydrolysis occurs in the absence of a catalyst and is carried out at a temperature in the range between about 150 °C and about 250 °C.

[0033] E4. The method according to embodiment E1, wherein the hydrolysis or partial hydrolysis occurs in the presence of an acid catalyst.

[0034] E5. The method according to embodiment E4, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0035] E6. The method according to embodiment E4, wherein the hydrolysis or partial hydrolysis is carried out in the presence of an acid catalyst and a cocatalyst, the cocatalyst forming an unstable hydrolysable molecule, such as an amine, an alcohol, or an amino alcohol, as described elsewhere herein.

[0036] E7. The method according to any one of embodiments E5 or E6, wherein the hydrolysis or partial hydrolysis occurs in the presence of an acid catalyst and at a temperature in the range between about 70 °C and about 150 °C.

[0037] E8. The method according to any one of embodiments E1-E7, wherein the PVB raw material is hydrolyzed to PVOH with a conversion rate of at least 90%.

[0038] E9. The method according to any one of embodiments E1-E7, wherein the PVB raw material is partially hydrolyzed to a conversion rate 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%.

[0039] E10. The method according to any one of embodiments E1-E7 and 9, wherein the partial hydrolysis of the PVB raw material produces a slurry, the slurry comprising water-insoluble PVB in the range of 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.

[0040] E11. The method according to any one of embodiments E1 - E7 and 9, wherein partial hydrolysis of the PVB raw material produces a slurry that contains more than 25%, more than 50%, more than 75%, between 25% and 75%, between 30% and 70%, between 35% and 65%, or between 40% and 60% water by weight.

[0041] E12. The method according to any one of embodiments E1 - E11, the method further comprising cooling the regenerated PVOH before the reaction step.

[0042] E13. The method according to any one of embodiments E1 - E12, the method further comprising centrifuging the solution before the filtration step to remove one or more insoluble components from the solution.

[0043] E14. The method according to embodiments E1 - E13, wherein the PVB raw material is derived from at least one of post - industrial recycled or post - consumer recycled materials.

[0044] E15. The method according to any one of embodiments E1 - E14, wherein the PVB raw material has a residual PVOH content of 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 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, and / or not more than 100%, not more than 90%, not more than 80%, not more than 70%, not more than 60%, not more than 50%, not more than 40%, not more than 35%, not more than 32%, not more than 30%, not more than 25%, not more than 22%, not more than 20%, not more than 19%, not more than 18%, not more than 17%, not more than 16%, not more than 15%, not more than 14%, not more than 13%, not more than 12%, not more than 11%, not more than 10%, not more than 9%, or not more than 8%.

[0045] E16. The method according to any one of embodiments E1 - E15, wherein the PVB raw material contains two or more PVB resins having different compositions from each other.

[0046] E17. The method according to any one of embodiments E1 - E16, wherein the PVB raw material comprises two or more PVB resins having different residual PVOH contents from each other.

[0047] E18. The method according to any one of embodiments E1 - E17, wherein based on the total weight of the PVB raw material, the PVB raw material comprises at least 1 phr, at least 5 phr, at least 10 phr, at least 15 phr, at least 20 phr, at least 25 phr, at least 30 phr, at least 35 phr, at least 40 phr, at least 45 phr, at least 50 phr, at least 55 phr, at least 60 phr, at least 65 phr, at least 70 phr, at least 75 phr, at least 80 phr, at least 85 phr or at least 90 phr, and / or not more than 100 phr, not more than 90 phr, not more than 85 phr, not more than 80 phr, not more than 75 phr, not more than 70 phr, not more than 65 phr, not more than 60 phr, not more than 55 phr, not more than 50 phr, not more than 45 phr, not more than 40 phr, not more than 35 phr, not more than 30 phr, not more than 25 phr, not more than 20 phr, not more than 15 phr or not more than 10 phr of a plasticizer.

[0048] E19. The method according to any one of embodiments E1 - E18, the method further comprising extracting a plasticizer from the PVB raw material.

[0049] E20. The method according to any one of embodiments E1 - E19, the method further comprising reducing the size of the 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 before the hydrolysis step.

[0050] E21. The method according to any one of embodiments E1 - E20, the method further comprising reacting the residual PVOH with butyraldehyde to produce the regenerated PVB having a residual PVOH content between 1% and 90%, between 5% and 30%, between 7% and 30% or between 16% and 20%.

[0051] E22. The method according to any one of embodiments E1 - E21, the method further comprising reacting the residual PVOH with butyraldehyde to produce a regenerated PVB having a target residual PVOH content, wherein the residual PVOH content of the PVB raw material is greater than 1%, greater than 2%, greater than 3%, greater than 4%, greater than 5% or greater than 10% of the target residual PVOH content.

[0052] E23. The method according to any one of embodiments E1-E22, the method further comprising recovering butyraldehyde produced in the hydrolysis step.

[0053] E24. The method according to any one of embodiments E1-E23, the method further comprising reacting the residual PVOH with butyraldehyde recovered from the hydrolysis step to produce recycled PVB.

[0054] This application generally relates to methods for converting polyvinyl butyral (PVB) to its original components (e.g., polyvinyl alcohol (PVOH) and butyraldehyde) by hydrolysis, and for producing purified PVB from the recovered PVOH and / or butyraldehyde. Generally, PVOH and butyraldehyde are starting materials in the PVB polymerization reaction. The methods described herein facilitate the reversal of the polymerization reaction by hydrolyzing or "deacetalizing" a PVB feed composition into its original components. The recycled PVOH and / or butyraldehyde recovered from the method can then be used to produce purified and / or recycled PVB. When the PVB being converted by hydrolysis is waste PVB (e.g., off-spec PVB, discarded PVB, and / or post-consumer PVB), the recycled materials produced from the waste PVB (e.g., r-PVOH, r-butyraldehyde, and r-PVB) can have recovered components from the waste PVB.

[0055] The PVB feed composition can be derived from post-consumer recycled PVB, from industrial off-spec PVB, and / or from industrial discarded PVB, where the industrial off-spec PVB can be generated during normal PVB resin production processes, and the industrial discarded PVB can be generated during normal PVB interlayer production processes. For example, even when polymerization is carried out under optimal or near-optimal conditions, some of the PVB produced by the polymerization of PVOH and butyraldehyde may be unusable (i.e., off-spec). Additionally, during the extrusion of PVB-containing interlayers, discarded PVB can be generated, for example, by trimming the edges of PVB sheets.

[0056] Accordingly, the methods described herein help reduce non-biodegradable waste, such as waste PVB, and produce 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 fresh starting components, with minimal impact in terms of comparable product quality and environmental impact.

[0057] For example, the methods described herein can include the following steps: (a) reducing the size of the PVB feed composition, (b) optionally dissolving the size-reduced PVB in a solvent, (c) hydrolyzing the PVB to produce a PVOH solution, (d) recovering the recycled PVOH from the solution, (e) producing recycled PVB from the recycled PVOH, (f) inspecting the recycled PVB for defects, (g) hydrolyzing the non-conforming PVB to produce additional PVOH, and (h) producing additional recycled PVB from the additional PVOH.

[0058] The methods described herein can further include the following steps: (a) producing PVB from fresh PVOH and butyraldehyde, (b) inspecting the produced PVB for defects, (c) optionally reducing the size of the non-conforming PVB, (d) hydrolyzing the non-conforming PVB to produce recycled PVOH, and (e) producing additional PVB from the recycled PVOH.

[0059] The systems and devices for practicing these methods and their details and features can vary. Non-limiting examples of systems, devices, and / or steps for implementing the embodiments of the present disclosure are shown in Figure 1-4 as follows.

[0060] Now referring to Figure 1 and 2 , the chemical recovery facility 100 is designed to process the PVB feedstock 102 to produce purified and / or recycled PVB, as described above. In some embodiments, the PVB feedstock 102 is derived from a chemical recovery feedstock that includes one or more PVB feed compositions from source materials. As used herein, the term "PVB feed composition" refers to used, discarded, and / or discarded PVB feed compositions, such as waste PVB that is typically sent to landfills.

[0061] The PVB feedstock 102 can include unprocessed or partially processed PVB feed compositions. As used herein, the term "unprocessed PVB feed composition" refers to a PVB feed composition that has not undergone any automated or mechanized sorting, washing, or shredding. The partially processed PVB feed composition can be derived from, for example, a recycling process. In one embodiment or in combination with any of the embodiments mentioned herein, the PVB feedstock 102 can include post-industrial recycled PVB feed compositions and / or post-consumer recycled PVB feed compositions.

[0062] In one embodiment or in combination with any of the embodiments mentioned herein, all or a portion of the PVB feedstock 102 can be derived from a recycling process facility that recovers glass from discarded and waste glass laminates containing PVB interlayers.

[0063] As used herein, the term "chemical recycling feedstock" refers to the total feedstock fed into the chemical recycling facility 100 and encompasses all feedstock streams introduced therein.

[0064] The chemical recycling facility 100 may include a feed system for introducing a chemical recycling feedstock (such as solid PVB resin) containing the PVB feedstock 102 into the facility. The feed system may be any conventional feed system for handling solid particle feeds, such as a screw feeder or a belt conveyor system.

[0065] In one embodiment or in combination with any embodiment mentioned herein, based on the total weight of the stream, the chemical recycling feedstock may contain at least 25 wt%, at least 50 wt%, at least 60 wt%, at least 65 wt%, at least 70 wt%, at least 75 wt%, at least 80 wt%, at least 85 wt%, at least 90 wt%, at least 95 wt% or at least 99 wt% of at least 1, 2, 3, 4, 5 or 6 PVB feed compositions. Additionally, or alternatively, based on the total weight of the stream, the chemical recycling feedstock may contain less than 99 wt%, less than 95 wt%, less than 90 wt%, less than 85 wt%, less than 80 wt%, less than 75 wt% or less than 70 wt% of at least 1, 2, 3, 4, 5 or 6 PVB feed compositions.

[0066] In one embodiment or in combination with any embodiment mentioned herein, the chemical recycling feedstock fed into the chemical recycling facility consists essentially of or consists of at least 1, 2, 3, 4, 5 or 6 PVB feed compositions.

[0067] In one embodiment or in combination with any embodiment mentioned herein, the chemical recycling feedstock fed into the chemical recycling facility consists essentially of or consists of a single PVB feed composition.

[0068] In one embodiment or in combination with any embodiment mentioned herein, based on the total weight of the stream, the chemical recycling feedstock contains 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.

[0069] In one embodiment or in combination with any embodiment mentioned herein, based on the total weight of the stream, the chemical recycling feedstock contains 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 polyolefins (e.g., polypropylene and / or polyethylene) and / or polyesters (e.g., polyethylene terephthalate).

[0070] In one embodiment or in combination with any of the embodiments mentioned, based on the total weight of the stream, the chemical recycle feedstock comprises no more than 20 wt%, no more than 15 wt%, no more than 12 wt%, no more than 10 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% or no more than 1 wt% of biological waste material. As used herein, the term "biological waste" refers to materials derived from living organisms. Exemplary biological waste materials include, but are not limited to, cotton, wood, sawdust, food waste, animals and animal parts, plants and plant parts, and manure.

[0071] In one embodiment or in combination with any of the embodiments mentioned herein, in addition to or in place of PVB, the PVB feedstock 102 may comprise one or more thermoplastic polymers. Examples of suitable thermoplastic polymers may include, but are not limited to, poly(vinyl acetal) resins, polyurethanes (PU), poly(ethylene-co-vinyl acetate) (EVA), polyvinyl chloride (PVC), poly(vinyl chloride-co-methyl acrylate), polyethylene, polyolefins, ethylene acrylate copolymers, poly(ethylene-co-butyl acrylate), silicone elastomers, epoxy resins, acid copolymers (e.g., ethylene / carboxylic acid copolymers and their ionomers), or combinations thereof.

[0072] 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 optionally be formed by the acetalization of polyvinyl alcohol with one or more aldehydes in the presence of an acid catalyst. The resulting resin can then be separated, stabilized, and dried according to known methods, such as those described in U.S. Patent 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 entirety. Unless otherwise specified, the resulting PVB resin can have a total acetalization percentage of at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 75 wt%, at least 80 wt%, at least 85 wt% or at least 90 wt% as measured according to ASTM D-1396. The total amount of aldehyde residues in the PVB resin can be collectively referred to as the acetal component, and the balance of the PVB resin is residual vinyl alcohol (hydroxyl) and residual acetate groups, which will be discussed in further detail below.

[0073] In one embodiment or in combination with any of the embodiments mentioned herein, the PVB resin in the PVB feedstock 102 can be a poly(vinyl alcohol butyral) resin, which mainly contains butyraldehyde residues, and based on the total weight of all aldehyde residues of the resin, can include, for example, no more than 50 wt%, no more than 40 wt%, no more than 30 wt%, no more than 20 wt%, no more than 10 wt%, no more than 5 wt% or no more than about 2 wt% of aldehyde residues other than butyraldehyde residues.

[0074] In one embodiment or in combination with any of the embodiments mentioned herein, the molecular weight of the PVB resin in the PVB feedstock 102 can be at least 50,000 Daltons, at least 70,000 Daltons or at least 100,000 Daltons and / or no more than 800,000 Daltons, no more than 550,000 Daltons, no more than 500,000 Daltons, no more than 450,000 Daltons, no more than 425,000 Daltons or no more than 300,000 Daltons, as measured by the size exclusion chromatography (SEC / LALLS) method using low-angle laser light scattering by Cott and Ouano. As used herein, the term "molecular weight" refers to the weight-average molecular weight (Mw). The molecular weight of the PVB resin can be in the range of about 50,000 Daltons to about 600,000 Daltons, about 70,000 Daltons to about 450,000 Daltons or about 100,000 Daltons to about 425,000 Daltons.

[0075] In one embodiment or in combination with any of the embodiments mentioned herein, based on the total weight of the PVB feed composition, the PVB feedstock 102 can contain 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 resin.

[0076] In one embodiment or in combination with any of the embodiments mentioned herein, the chemical recycling feedstock can comprise 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 PVB content relative to the second PVB feed composition. For example, the difference between the PVB contents of the first PVB feed composition and the second PVB feed composition can 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 term "different in weight percentage" or "the difference is at least... weight percentage" refers to the difference between two given weight percentages, calculated by subtracting one value from the other.

[0077] In one embodiment or in combination with any of the embodiments mentioned herein, the PVB feed composition can comprise two or more PVB resins having different compositions. For example, in some embodiments, one or both outer layers of the laminate forming the PVB feed composition can be formed of a first PVB resin, while the core layer or inner layer can be formed of a second PVB resin. In such embodiments, the first PVB resin used to form the outer layer can have a residual polyvinyl alcohol content and / or a residual acetate content that is at least 2 wt%, at least 3 wt%, at least 4 wt%, at least 5 wt%, at least 6 wt% or at least 8 wt% higher or lower than the residual polyvinyl alcohol content and / or the residual acetate content of the second PVB resin used to form the inner layer.

[0078] As used herein, the terms "residual polyvinyl alcohol content" and "residual acetate content" refer to the amounts of hydroxyl and acetate groups, respectively, remaining on the resin after processing is complete. For example, polyvinyl butyral can be produced by hydrolyzing polyvinyl acetate into polyvinyl alcohol and then acetalizing the polyvinyl alcohol ("PVOH") with butyraldehyde to form polyvinyl butyral. During the hydrolysis of polyvinyl acetate, not all acetate groups are converted to hydroxyl groups, and residual acetate groups remain on the resin. Similarly, during the acetalization of polyvinyl alcohol, not all hydroxyl groups are converted to acetal groups, which also leaves residual hydroxyl groups on the resin. Thus, most poly(vinyl acetal) resins include residual PVOH groups (as vinyl hydroxyl groups) and residual acetate groups (as vinyl acetate groups) as part of the polymer chain. Unless otherwise specified, the residual PVOH content and the residual acetate content are expressed as weight percentages based on the weight of the polymer resin and are measured according to ASTM D-1396.

[0079] In one embodiment or in combination with any embodiment mentioned herein, the PVB feed composition may comprise 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 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90%, and / or not more than 100%, not more than 90%, not more than 80%, not more than 70%, not more than 60%, not more than 50%, not more than 40%, not more than 35%, not more than 32%, not more than 30%, not more than 25%, not more than 22%, not more than 20%, not more than 19%, not more than 18%, not more than 17%, not more than 16%, not more than 15%, not more than 14%, not more than 13%, not more than 12%, not more than 11%, not more than 10%, not more than 9% or not more than 8% by weight of residual polyvinyl alcohol (PVOH). For example, the PVB feed composition may comprise a residual polyvinyl alcohol (PVOH) content percentage in the range of from about 14 wt% to about 45 wt%, from about 16 wt% to about 30 wt%, from about 18 wt% to about 25 wt%, from about 18.5 wt% to about 20 wt% or from about 19.5 wt% to about 21 wt%.

[0080] In one embodiment or in combination with any embodiment mentioned herein, the chemical recycling feedstock may comprise 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 residual PVOH content relative to the second PVB feed composition. For example, the difference between the residual PVOH contents of the first PVB feed composition and the second PVB feed composition 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%.

[0081] In one embodiment or in combination with any embodiment mentioned herein, the PVB feed composition may comprise 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% of residual acetate content.

[0082] In one embodiment or in combination with any embodiment mentioned herein, the chemical recycling feedstock can comprise 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 residual acetate content relative to the second PVB feed composition. For example, the difference between the residual acetate contents of the first PVB feed composition and the second PVB feed composition can 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 not more than 15 wt%, not more than 13 wt%, not more than 11 wt%, not more than 9 wt%, not more than 8 wt%, not more than 6 wt%, not more than 5 wt%, not more than 4 wt%, not more than 3 wt%, not more than 2 wt%, not more than 1 wt% or not more than 0.5 wt%.

[0083] In one embodiment or in combination with any embodiment mentioned herein, the chemical recycling feedstock can comprise one or more PVB feed compositions having a residual PVOH content that is 1%, 2%, 3%, 4%, 5% or 10% higher than the target residual PVOH content of the recycled PVB produced as described herein.

[0084] In one embodiment or in combination with any embodiment mentioned herein, the PVB feed composition can comprise at least one plasticizer. For example, the PVB feed composition can comprise at least 1 phr, at least 5 phr, at least 10 phr, at least 15 phr, at least 20 phr, at least 25 phr, at least 30 phr, at least 35 phr, at least 40 phr, at least 45 phr, at least 50 phr, at least 55 phr, at least 60 phr, at least 65 phr, at least 70 phr, at least 75 phr, at least 80 phr, at least 85 phr or at least 90 phr, and / or not more than 100 phr, not more than 90 phr, not more than 85 phr, not more than 80 phr, not more than 75 phr, not more than 70 phr, not more than 65 phr, not more than 60 phr, not more than 55 phr, not more than 50 phr, not more than 45 phr, not more than 40 phr, not more than 35 phr, not more than 30 phr, not more than 25 phr, not more than 20 phr, not more than 15 phr, not more than 10 phr, not more than 5 phr, not more than 4 phr, not more than 3 phr, not more than 2 phr, not more than 1 phr, not more than 0.5 phr or not more than 0.1 phr of at least one plasticizer. As used herein, the term "parts per hundred resin" or "phr" refers to the amount of plasticizer present, by weight, relative to one hundred parts of resin.

[0085] In one embodiment or in combination with any embodiment mentioned herein, the chemical recycling feedstock can comprise 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 content relative to the second PVB feed composition. For example, the difference between the plasticizer contents of the first PVB feed composition and the second PVB feed composition can 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 not more than 15 phr, not more than 13 phr, not more than 11 phr, not more than 9 phr, not more than 8 phr, not more than 6 phr, not more than 5 phr, not more than 4 phr, not more than 3 phr, not more than 2 phr, not more than 1 phr, not more than 0.5 phr, or not more than 0.1 phr.

[0086] In one embodiment or in combination with any embodiment mentioned herein, the plasticizer can be 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, cyclohexyl hexyl adipate, diisononyl adipate, heptyl nonyl adipate, bis(butoxyethyl) adipate, dihexyl adipate, dibutyl sebacate, triethylene glycol di-(2-ethylhexanoate) (“3GEH”), dioctyl sebacate, bis-(methoxyethyl) ester, 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.

[0087] In one embodiment or in combination with any embodiment mentioned herein, the chemical recycling feedstock can comprise 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. Optionally, the first PVB feed composition and the second PVB feed composition can have the same plasticizer.

[0088] In one embodiment or in combination with any embodiment mentioned herein, based on the total weight of the PVB feed composition, the PVB feed composition may comprise 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, glaze, UV stabilizer, pigment, adhesion control agent, antioxidant, rubber, silicate or a combination of two or more thereof.

[0089] In one embodiment or in combination with any embodiment mentioned herein, based on the total weight of the PVB feed composition, the PVB feed composition may comprise 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% of glass.

[0090] Generally, the amount of solid contaminants in the PVB feed composition can be measured by an alcohol solubility test, in which the PVB resin and plasticizer will dissolve in the specified alcohol while the solid contaminants will not. In one embodiment or in combination with any embodiment mentioned herein, based on the total weight of the PVB feed composition, 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% of one or more alcohol-insoluble components. Additionally, or alternatively, based on the total weight of the PVB feed composition, the PVB feed composition may comprise 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 one or more alcohol-insoluble components. Generally, the alcohol may be ethanol.

[0091] In one embodiment or in combination with any embodiment mentioned herein, the insoluble components are insoluble in ethanol and may comprise glass, metal, polymer, salt, silicate, calcium, calcium derivative, sodium derivative or a combination thereof.

[0092] Typically, in one or more embodiments, the insoluble component can include at least one polymer, such as polyolefin, polyester, rubber, polyamide, polystyrene, or a combination of two or more thereof. In one embodiment or in combination with any of the embodiments mentioned herein, the PVB feed composition can 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 can include 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 at least one insoluble polymer. Polymers that are insoluble in alcohol (e.g., ethanol) can be derived from packaging materials, recycled windshields, and / or mounting materials.

[0093] In one embodiment or in combination with any of the embodiments mentioned herein, the PVB feed composition can 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 rubber. Additionally, or alternatively, the PVB feed composition can include 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 rubber.

[0094] In one embodiment or in combination with any embodiment mentioned herein, the PVB feed composition can 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% of glass, metal, salt, silicate, calcium, calcium derivative, sodium derivative or a combination thereof. Additionally, or alternatively, the PVB feed composition can comprise 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 glass, metal, salt, silicate, calcium, calcium derivative, sodium derivative or a combination thereof.

[0095] In one embodiment or in combination with any embodiment mentioned herein, based on the total weight of the PVB feed composition, the PVB feed composition can comprise 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% of glass.

[0096] The amount of insoluble components in the PVB feed composition can be measured by combining 20 grams of the PVB feed composition with 200 mL of 190 proof ethanol in a stirred container and stirring the mixture for four hours. The resulting solution is then sieved through a filter (12 to 30 mesh), and the sieved solution is centrifuged at 4,200 rpm for 20 minutes. The supernatant is then poured into an aluminum pan and dried by evaporation in a fume hood until no weight loss is detected. Subsequently, the material is further dried in an oven at 50 °C for two hours and then pressed into a sheet with a thickness of 760 microns. The resulting sheet and precipitate are analyzed using a Bomem FT-NIR analyzer.

[0097] Additionally, or alternatively, the amount of solid contaminants can also be measured by determining the ash content of the PVB feed composition according to ASTM D5630-13.

[0098] In one embodiment or in combination with any of the embodiments described herein, based on the total weight of the PVB feed composition, the PVB feed composition can comprise an ash content of 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%, as measured according to ASTM D5630-13. Additionally, or alternatively, based on the total weight of the PVB feed composition, the PVB feed composition can comprise an ash content of 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%, less than 1 wt% or less than 0.5 wt%, as measured according to ASTM D5630-13.

[0099] Examples of suitable PVB feed compositions for use in the chemical recovery facilities described herein can include, but are not limited to, post-industrial or post-consumer recycled materials such as post-industrial PVB feed waste and / or post-consumer PVB feed waste. Exemplary post-industrial PVB feed compositions can include, for example, PVB waste, broken laminated glass, off-spec PVB resin, oversized materials from PVB production, or combinations of two or more thereof.

[0100] Specific embodiments of the PVB feed composition (in the form of a laminate) are described in detail in PCT Patent Application Publication No. WO 2021 / 127206 and U.S. Patent Application Publication No. 2017 / 0285339, the entire contents of which are incorporated herein by reference to the extent not inconsistent with the present disclosure.

[0101] Typically, the formulation of the PVB feed composition can vary over time depending on the source of the PVB feed composition. For example, the amounts of PVB resin, plasticizer, and / or solid contaminants (e.g., glass, rubber, etc.) can vary with each PVB feed composition introduced into the chemical recovery facility.

[0102] In one embodiment or in combination with any of the embodiments described herein, one or more of the following criteria may apply to the PVB feed composition being introduced into the chemical recycling facility 100: (i) the amount of PVB resin in the PVB feed composition varies by at least 2 wt% over time, (ii) the amount of plasticizer in the PVB feed composition varies by at least 2 phr over time, (iii) the amount of solid contaminants in the PVB feed composition varies by at least 2 wt% over time, or (iv) the ratio of PVB resin to plasticizer varies by at least 2 wt% over time. In many cases, at least two, at least three, or all four criteria are met. This may be due to differences in the sources from which the PVB feed composition is derived.

[0103] As discussed above, the composition of the PVB feed composition fed into the chemical recycling facility can vary depending on its source. However, the chemical recycling facility can be designed to facilitate such variation in the PVB feed composition.

[0104] In one embodiment or in combination with any of the embodiments described herein, the amount of PVB resin in the PVB feed composition varies by at least 2 wt%, at least 3 wt%, at least 4 wt%, at least 5 wt%, at least 6 wt%, at least 7 wt%, at least 8 wt%, at least 9 wt%, at least 10 wt%, at least 11 wt%, at least 12 wt%, at least 13 wt%, at least 14 wt%, or at least 15 wt% and / or less than 25 wt% over a period of 1 hour, 6 hours, 12 hours, 18 hours, 1 day, 2 days, 3 days, 4 days, or one week. As described above, the difference can be calculated based on the difference between two given weight percentages over the specified period, by subtracting one value from the other.

[0105] In one embodiment or in combination with any of the embodiments described 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 one week. As described above, the difference can be calculated based on the difference between two given phr values over the specified period, by subtracting one value from the other.

[0106] In one embodiment or in combination with any embodiment mentioned herein, the amount of solid contaminants in the PVB feed composition varies by at least 2 wt%, at least 3 wt%, at least 4 wt%, at least 5 wt%, at least 6 wt%, at least 7 wt%, at least 8 wt%, at least 9 wt%, at least 10 wt%, at least 11 wt%, at least 12 wt%, at least 13 wt%, at least 14 wt% or at least 15 wt% and / or is less than 25 wt% over a period of 1 hour, 6 hours, 12 hours, 18 hours, 1 day, 2 days, 3 days, 4 days or one week. As described above, the difference can be calculated based on the difference between two given weight percentages over the specified period, by subtracting one value from the other.

[0107] 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 is less than 25% over a period of 1 hour, 6 hours, 12 hours, 18 hours, 1 day, 2 days, 3 days, 4 days or one week. As described above, the difference can be calculated based on the difference between two given ratio values over the specified period, by subtracting one value from the other.

[0108] The above difference measurements can be made by sampling the PVB feed composition over a specified period (e.g., over one week). To produce consistent measurements, a 20-gram sample of the PVB feed composition can be obtained and tested by solubility analysis as discussed above.

[0109] Still referring Figure 1 and 2 , the PVB feedstock 102 can be subjected to a size reduction operation at unit 104. As described above, the size reduction operation reduces the particle size of the PVB feed composition prior to its hydrolysis. This size reduction can be provided by, for example, grinding / granulation, chopping, cutting, mincing or other comminution methods, which provide PVB composition particles of reduced size. Such mechanical size reduction operations can include size reduction steps other than crushing and / or compressing.

[0110] In one embodiment, unit 104 reduces the average particle size of the respective fragments of PVB feedstock 102 by at least 10%, at least 25%, at least 50% or at least 75% of its original size. Additionally or alternatively, unit 104 reduces the average particle size of the respective fragments of PVB feedstock 102 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. Additionally or alternatively, such as when PVB feedstock 102 includes interlayer waste, unit 104 reduces the average particle size of the respective fragments of PVB feedstock 102 to a "flake" having a size smaller than 10 mm × 10 mm, 8 mm × 8 mm, 6 mm × 6 mm or 5 mm × 5 mm.

[0111] In some embodiments, the size-reduced PVB 106 discharged from unit 104 is optionally washed and then optionally processed to extract plasticizers therefrom in units 108 and 110, respectively. For example, in embodiments where the PVB feed composition is derived from post-consumer recycled materials (such as PVB baffles obtained from glass recyclers), unit 104 pre-washes the size-reduced PVB 106 to remove insoluble components therefrom. The pre-washing step can reduce the ash content of the PVB to less than about 0.5 wt%, about 0.4 wt%, about 0.3 wt%, about 0.2 wt% or about 0.1 wt% of the PVB feed composition. The pre-washing step can also reduce the iron content of the PVB to less than about 50 ppm, about 40 ppm, about 30 ppm, about 20 ppm, about 10 ppm or about 5 ppm.

[0112] At unit 108, the size-reduced PVB 106 is suspended in water and stirred for a certain duration. The temperature of the water can be in the range between about 10°C and about 100°C, between about 20°C and about 90°C, between about 25°C and about 75°C or between about 40°C and about 60°C, and the PVB suspension is stirred for a duration of at least 15 minutes, at least 30 minutes, at least 45 minutes or at least 1 hour. In some embodiments, one or more metal chelating agents can be introduced into unit 108 to facilitate the recovery of contaminants from the suspension. Exemplary metal chelating agents include, but are not limited to, citric acid, ethylenediaminetetraacetic acid (EDTA), etc.

[0113] In addition, the pH of the suspension can be maintained at an acidic level to neutralize any base remaining on, for example, the PVB baffle obtained from the glass removal step. The pH of the suspension can be maintained at less than about 7, less than about 6, less than about 5, less than about 4, less than about 3, less than about 2, or less than 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 duration, the PVB can be filtered, rinsed with additional water on the filter to remove residual acid, and discharged from unit 108 as washed PVB 112.

[0114] At unit 110, the plasticizer is extracted from the washed PVB 112. This optional plasticizer extraction step can be carried out in embodiments where the PVB feed composition is derived from, for example, low-quality industrial post-PVB interlayer waste. In such cases, the plasticizer is extracted from the washed PVB 112 prior to the hydrolysis step to enable the hydrolysis to proceed in an efficient manner. In some embodiments, the plasticizer extraction step is carried out with supercritical carbon dioxide or by suspending the washed PVB 112 in an extraction solution. The extraction solution can include different proportions of water, alcohols, and combinations thereof. Exemplary alcohols include, but are not limited to, methanol, ethanol, and isopropanol.

[0115] The number of extraction stages to be carried out can be based on the extraction time, extraction temperature, and / or the polymer loading of the solution. For example, the extraction time can be a duration of 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. The extraction temperature can 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 1, at least 2, at least 3, or at least 4 extraction stages can be carried out to reduce the phr of the 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.

[0116] After plasticizer extraction, the mixture of washed PVB 112 and the extraction solution can be filtered, and the filtrate can be dried by evaporating the volatile substances to obtain dried PVB 114. Such volatile materials can be recovered, for example, by distillation, and the plasticizer, alcohol, and / or water can be recovered for further use. The dried PVB 114 obtained from the plasticizer extraction step can be examined to verify that its average particle size is 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. If necessary, further size reduction can be carried out to reduce the size of the dried PVB 114 to the average particle size described above. In an alternative embodiment, unit 108 is positioned after the washing and plasticizer extraction steps.

[0117] Reference Figure 1 , the dried PVB 114 is hydrolyzed in unit 116 to produce solution 118, which contains hydrolysis products in the form of a number of recycled component products that are directly derived from the PVB-containing composition. For example, the hydrolysis products can include several recycled component products derived from the hydrolysis of the PVB resin, which will be described in more detail below. In the illustrated embodiment, the dried PVB 114 can be hydrolyzed in the presence of water 120, alcohol 122, and optionally acid catalyst 124 to produce solution 118 containing regenerated PVOH and vapor stream 126.

[0118] Optionally, in Figure 2 the illustrated embodiment, the dried PVB 114 can be dissolved in alcohol 122 before the hydrolysis step is carried out. For example, the dried PVB 114 can be fed into dissolution and filtration unit 128, where the dried PVB 114 is mixed with a solvent such as alcohol 122 for a residence time that promotes the dissolution of the dried PVB 114 into the alcohol 122 to produce PVB solution 130. In some embodiments, dissolving the dried PVB 114 in a solvent helps to identify any residual insoluble contaminants in the PVB feed composition remaining from the washing and / or plasticizer extraction steps. Any residual contaminants can be filtered and removed from the resulting solution at unit 128 before feeding into unit 116.

[0119] The PVB solution 130 fed into unit 116 is hydrolyzed, which will be described in more detail below. The dried PVB 114 can be completely or partially dissolved before being fed into unit 116. For example, the PVB solution 130 can have a total solids content of less than about 25 wt%, less than about 20 wt%, less than about 15 wt%, less than about 10 wt%, less than about 5 wt%, less than about 2.5 wt%, or less than about 1 wt% of the solution.

[0120] As a result of the hydrolysis reaction, PVB is typically converted to, for example, PVOH and butyraldehyde. The regenerated PVOH is generally soluble and thus 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 can contain residual amounts of regenerated PVOH, water, polyvinyl acetate (PVAC), alcohol, catalyst, butyraldehyde, and / or butyral. In addition, the vapor stream 126 can contain regenerated butyraldehyde and alcohol.

[0121] The degree of hydrolysis achieved (i.e., the conversion of PVB to PVOH) can 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 any particular theory, it is believed that hydrolyzed PVB is soluble when its PVOH content is greater than a PVOH content threshold. Thus, the converted PVOH can be in the form of a water-insoluble PVB resin having a higher residual PVOH content and / or a reduced butyraldehyde content than the PVB resin. The converted PVOH can also be in the form of water-soluble PVOH (i.e., PVB is hydrolyzed to greater than the PVOH content threshold).

[0122] In one embodiment or in combination with any of the embodiments mentioned herein, the water-insoluble PVB 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%.

[0123] In an exemplary embodiment, the above hydrolysis factors can be adjusted to obtain an average PVB to PVOH conversion 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%.

[0124] Thus, in one embodiment, the resulting r-PVOH solution 118 contains water, PVOH, and residual portions of one or more additional components. The concentration of water in the r-PVOH solution 118 can 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.

[0125] The concentration of the water-soluble PVOH in the r-PVOH solution 118 can be less than 20%, less than 15%, less than 10%, less than 5%, less than 2%, less than 1%, or between 1% and 20%, between 1% and 15%, between 1% and 10%, or between 1% and 5% by weight of the r-PVOH solution 118.

[0126] The concentration of the residual portion can be less than 20%, less than 15%, less than 10%, less than 5%, less than 2%, less than 1%, or between 1% and 20%, between 1% and 15%, between 1% and 10%, or between 1% and 5% by weight of the r-PVOH solution 118.

[0127] The residual portion can include residual polyvinyl acetate (PVAC), residual alcohol, residual catalyst, butyraldehyde, and / or butyral. The concentrations of these residual portions can each be 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.

[0128] As described above, the conversion of PVB to PVOH can be based on various factors. In one embodiment or in combination with any embodiment mentioned herein, the hydrolysis step is carried out at a temperature in the range between about 70 °C and about 250 °C. Generally, when hydrolysis is carried out in the presence of an acid catalyst 124, the hydrolysis can be carried out at a lower temperature within this range. For example, the hydrolysis carried out in the presence of an acid catalyst 124 can occur at a temperature in the range 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.

[0129] Optionally, when hydrolysis does not occur in the presence of an acid catalyst 124, the hydrolysis can be carried out at a relatively higher temperature within the range described above. For example, the hydrolysis that does not occur in the presence of an acid catalyst 124 can occur at a temperature in the range 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.

[0130] 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.

[0131] In one embodiment or in combination with any of the embodiments described herein, when present, the concentration of the 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%, 10%, less than about 8%, less than about 5%, less than about 4%, less than about 3%, less than about 2%, less than about 1%, less than about 0.5%, less than about 0.1%, between about 0.5% and about 10%, between about 0.5% and about 8%, between about 0.5% and about 5%, between about 1% and about 5%, or between about 2% and about 4% by weight of the hydrolysis solution.

[0132] In some embodiments, the vapor stream 126 discharged from unit 116 can be directed to a distillation / separation unit 132. As described above, the vapor stream 126 includes a mixture of regenerated butyraldehyde and alcohol. Unit 132 is operable to separate the mixture into its component parts such that the alcohol 134 and the regenerated butyraldehyde 136 are discharged from unit 132 as separate streams. The alcohol 134 can be recycled for use in unit 116 ( Figure 1 ) or unit 128 ( Figure 2 ), and the regenerated butyraldehyde 136 can be stored and / or directed for use in units downstream from unit 116, as will be described in more detail below.

[0133] In addition to residual PVAC, residual alcohol, residual catalyst, butyraldehyde, and / or butyral, the r-PVOH solution 118 can also contain one or more insoluble components remaining from the PVB washing step at unit 108 and / or generated 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 can optionally be 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 can 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.

[0134] A portion of the resulting filtered r-PVOH solution 142 can be recycled and stored for future use. Additionally, in the illustrated embodiment, a portion of the resulting filtered r-PVOH solution 142 can also be used to produce recycled PVB in the chemical recovery facility 100. In one embodiment or in combination with any of the embodiments mentioned herein, the r-PVOH solution 142 is cooled in unit 144 and then used to produce r-PVB 146 in unit 148. At unit 144, the r-PVOH solution 142 can be cooled to a temperature below 150 °C, below 125 °C, below 100 °C, below 75 °C, below 50 °C, below 25 °C, below 15 °C, below 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 at unit 148 that facilitates PVB production.

[0135] At unit 148, the r-PVOH solution 142 is combined with water 150 and butyraldehyde, optionally in the presence of an acid catalyst 124, to produce r-PVB 146. The butyraldehyde can be sourced as fresh butyraldehyde 152 and / or as recycled r-butyraldehyde 136 recovered from unit 132. Fresh PVOH 154 can also be fed to unit 148 to produce r-PVB 146.

[0136] As used herein, "fresh" refers to a component provided from a source different from the PVB hydrolysis reaction described herein. For example, the component can be purchased or produced in a separate industrial process.

[0137] In one embodiment or in combination with any of the embodiments mentioned herein, at unit 156, r-PVB 146 is inspected for defects including at least one of oversized, visual, compositional, gelation, or contamination. PVB produced from the reaction of water, PVOH, and butyraldehyde is herein generally defined as "in-specification" and "out-of-specification" based on an inspection for such defects. In-specification PVB does not have any of the defects described above. Out-of-specification PVB has at least one of the defects described above. At unit 156, the in-specification PVB 158 is separated from the out-of-specification PVB 160 based on the inspection. The in-specification PVB 158 is discharged from unit 156 and recycled. In the illustrated embodiment, the out-of-specification PVB 160 is discharged from unit 156, optionally sized down at unit 162 if oversized, and directed to unit 116 to produce additional recycled PVOH therefrom.

[0138] Now refer Figure 3 and 4, the chemical recycling facility 164 is designed to produce PVB particles from the reaction of fresh virgin components and process (i.e., hydrolyze) any out-of-specification PVB particles to produce recycled PVOH that can be used to produce additional PVB particles. In the exemplary illustration, fresh PVOH 166, fresh butyraldehyde 168, water 170, and optionally an acid catalyst 172 (e.g., acid catalyst 124) and γ-butyraldehyde 174 are combined in unit 176 to produce PVB particles 178.

[0139] In one embodiment or in combination with any embodiment mentioned herein, the PVB particles 178 are inspected at unit 180 for defects including at least one of oversized, visual, compositional, gelation, or contamination. At unit 180, the in-specification PVB 182 is separated from the out-of-specification PVB 184 based on the inspection. The in-specification PVB 182 is discharged from unit 180 and recycled. The out-of-specification PVB 184 is discharged from unit 180, optionally reduced in size based on the process conditions associated with unit 104 ( Figure 1 and 2 as shown therein), and directed to unit 188 to produce r-PVOH therefrom.

[0140] Reference Figure 3 , the out-of-specification PVB 184 is hydrolyzed at unit 188 to produce a solution 190 containing recycled PVOH and a vapor stream 192. The out-of-specification PVB 184 can be hydrolyzed in the presence of water 194, alcohol 196, and optionally an acid catalyst 172 to produce an r-PVOH solution 190. As described above, the hydrolysis is carried out according to the process conditions associated with unit 116 ( Figure 1 and 2 as shown therein).

[0141] A portion of the resulting r-PVOH solution 190 can be recycled and stored for future use. Additionally, in the illustrated embodiment, a portion of the r-PVOH solution 190 can also be used to produce recycled PVB particles in the chemical recycling facility 164. In one embodiment or in combination with any embodiment mentioned herein, the r-PVOH solution 190 is cooled in unit 198 and then used to produce additional PVB particles 178 in unit 176.

[0142] Optionally, in Figure 4In the illustrated embodiment, off-spec PVB 184 can be dissolved in alcohol 196 prior to the hydrolysis step. For example, off-spec PVB 184 can be fed to dissolution unit 200 where the off-spec PVB 184 is mixed with a solvent, such as alcohol 196, for a residence time that promotes dissolution of the off-spec PVB 184 into the alcohol 196 to produce a PVB solution 202. The PVB solution 202 can then be fed to unit 188 and hydrolyzed as described above. The off-spec PVB 184 can be completely or partially dissolved prior to being fed to unit 188.

[0143] Referring again to Figure 3 and 4 , the vapor stream 192 exiting unit 188 can be directed to distillation / separation unit 204. The vapor stream 192 includes a mixture of regenerated butyraldehyde and alcohol. Unit 204 is operable to separate the mixture into its component parts such that alcohol 196 and regenerated butyraldehyde 174 are discharged from unit 204 as separate streams. The alcohol 196 can optionally be recycled for use in unit 188 ( Figure 3 ) or unit 200 ( Figure 4 ), and the regenerated butyraldehyde 174 can be stored and / or directed for use in producing PVB particles 178 in unit 176 as described above.

[0144] Now referring to Figure 5 and 6 , the dry PVB 114 is partially hydrolyzed in unit 116 to produce a reaction product that includes a number of hydrolysis products in the form of recycled component products, which are directly derived from the PVB-containing composition. For example, as described above, the hydrolysis products can include several recycled component products derived from the hydrolysis of the PVB resin. In the illustrated embodiment, the dry PVB 114 can be hydrolyzed in the presence of water 120, alcohol 122, and optionally an acid catalyst 124 to produce a reaction product that includes a water-insoluble PVB with a residual PVOH content higher than the PVB resin and a vapor stream 126. As will be described in more detail below, the partial hydrolysis of the PVB-containing composition limits the solubility of the PVB such that the reaction product is in the form of a PVB slurry 204 of insoluble PVB, for example, in the liquid discharged from unit 116.

[0145] For example, the degree of hydrolysis achieved at unit 116 (i.e., the conversion 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 any particular theory, it is believed that hydrolyzed PVB is soluble when its PVOH content is greater than a PVOH content threshold. Thus, the converted PVOH can be in the form of a water-insoluble PVB resin having a higher residual PVOH content and / or a reduced butyraldehyde content than the PVB resin. The converted PVOH can also be in the form of water-soluble PVOH (i.e., PVB is hydrolyzed to greater than the PVOH content threshold).

[0146] In Figure 5-10 In the illustrated embodiments, the above hydrolysis factors are adjusted to produce a partially hydrolyzed reaction product. As used herein, "partially hydrolyzed" refers to the process of hydrolyzing PVB to produce a reaction product that includes water-insoluble PVB. Partial hydrolysis can be defined by a reduction in the PVB content of the PVB feed composition (i.e., conversion from water-insoluble PVB to water-soluble PVOH) of at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or up to 100% of its starting PVB content by weight. Optionally, partial hydrolysis can be defined by a reduction in the acetal content of the PVB feed composition of at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or up to 100% 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.

[0147] In one embodiment or in combination with any of the embodiments mentioned herein, the water-insoluble PVB 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%.

[0148] In one embodiment or in combination with any of the embodiments mentioned herein, the partial hydrolysis step is carried out at a temperature in the range between about 70°C and about 250°C. Generally, when hydrolysis is carried out in the presence of acid catalyst 124, the hydrolysis can be carried out at a lower temperature within this range. For example, hydrolysis carried out in the presence of acid catalyst 124 can occur at a temperature in the range 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.

[0149] Optionally, when hydrolysis does not occur in the presence of acid catalyst 124, the hydrolysis can be carried out at a relatively higher temperature within the range described above. For example, hydrolysis that is not carried out in the presence of acid catalyst 124 can occur at a temperature in the range 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.

[0150] In one embodiment or in combination with any of the embodiments 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.

[0151] Referring again to Figure 5-7 , the reaction product discharged from unit 116 is in the form of PVB slurry 204, which comprises water-insoluble PVB and water. In one embodiment or in combination with any of the embodiments mentioned herein, PVB slurry 204 contains less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 5 wt%, between 0% and 25 wt%, between 1% and 25 wt%, between 5% and 25 wt%, or between 10% and 20 wt% of water-insoluble PVB. Additionally, in one embodiment or in combination with any of the embodiments mentioned herein, PVB slurry 204 contains more than 25 wt%, more than 50 wt%, more than 75 wt%, between 25% and 75 wt%, between 30% and 70 wt%, between 35% and 65 wt%, or between 40% and 60 wt% of water.

[0152] In the embodiment shown, PVB slurry 204 is used to produce r-PVB 206 at unit 208. Specifically, at unit 208, optionally in the presence of acid catalyst 124, PVB slurry 204 is combined with water 210 and butyraldehyde to produce r-PVB 206. That is, the residual PVOH of the water-insoluble PVB in PVB slurry 204 reacts with butyraldehyde to produce r-PVB 206. Butyraldehyde can be sourced as fresh butyraldehyde 212 and / or as recycled butyraldehyde 136 recovered from unit 132.

[0153] As Figure 5 and 6 shown, the partial hydrolysis and PVOH acetalization (reaction) steps are carried out in separate units 116 and 208, respectively. Optionally, in the embodiment shown in Figure 7 , the partial hydrolysis and PVOH acetalization steps are carried out in the same unit 216. For example, the partial hydrolysis of dry PVB 114 can be carried out in unit 216 as described above. After the PVB is converted to the desired extent, one or more of fresh butyraldehyde 212 or recycled butyraldehyde 136 can be fed into the unit to produce r-PVB 206 therefrom.

[0154] PVOH acetalization reduces the PVOH content in PVB, such that r-PVB 206 has a lower residual PVOH content than water-insoluble PVB. In some embodiments, the PVOH acetalization is controlled to achieve a target residual PVOH content in r-PVB 206. In one embodiment or in combination with any of the embodiments mentioned herein, the produced r-PVB has a residual PVOH content between 1% and 90%, between 5% and 30%, between 7% and 30, or between 16% and 20% (e.g., the target residual PVOH content).

[0155] Now referring to Figure 8-10 , PVB particles 178 are produced from the reaction of fresh raw 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 of the embodiments mentioned herein, the PVB particles 178 are inspected at unit 180 for defects. Based on the inspection, the PVB 182 that meets the specifications is separated from the PVB 184 that does not meet the specifications.

[0156] Referring to Figure 8 and 9 , the non-conforming PVB 184 is partially hydrolyzed in unit 188 to produce a reaction product containing many hydrolysis products in the form of recycled component products, which are directly derived from the PVB-containing composition. For example, as described above, the hydrolysis products can include several recycled component products derived from the hydrolysis of the PVB resin. In the embodiment shown, the non-conforming PVB 184 can be hydrolyzed in the presence of water 120, alcohol 122, and optionally acid catalyst 124 to produce a reaction product containing water-insoluble PVB with a residual PVOH content higher than that of the PVB resin and a vapor stream 192. As described above, the solubility of the partially hydrolyzed PVB is based on the degree of hydrolysis of the PVB-containing composition. Therefore, in some embodiments, the reaction product is in the form of a PVB slurry 218 discharged from unit 116.

[0157] In the illustrated embodiment, PVB slurry 218 is used to produce r-PVB 220 at unit 208. Specifically, at 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, the residual PVOH of the water-insoluble PVB in PVB slurry 218 reacts with butyraldehyde to produce r-PVB 220. Butyraldehyde can be sourced as fresh butyraldehyde 224 and / or as recycled butyraldehyde 174 recovered from unit 204.

[0158] As Figure 8 and 9 shown, the partial hydrolysis and PVOH acetalization (reaction) steps are carried out in separate units 188 and 208, respectively. Optionally, in the Figure 10 illustrated embodiment, the partial hydrolysis and PVOH acetalization steps are carried out in the same unit 216. For example, the partial hydrolysis of off-spec PVB 184 can be carried out in unit 216 as described above. After the PVB is converted to the desired extent, one or more of fresh butyraldehyde 224 or recycled butyraldehyde 174 can be fed into unit 216 to produce r-PVB 220 therefrom.

[0159] In one embodiment or in combination with any of the embodiments mentioned herein, r-PVB 220 is inspected for defects at inspection unit 225, including at least one of oversized, visual, compositional, gelation, or contamination defects. At 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 recovered. The off-spec PVB 228 is discharged from unit 225, optionally sized down in unit 186, and recycled to unit 188 to produce additional PVB slurry 218 therefrom.

[0160] Now referring to Figure 11 and 12 , PVB 230 (e.g., dry 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 containing a number of hydrolysis products in the form of recycled component products, which are directly derived from the PVB-containing composition. For example, as described above, the hydrolysis products can include several recycled component products derived from the hydrolysis of the PVB resin. In the illustrated embodiment, PVB can be hydrolyzed in the presence of water 120, aldehyde scavenger 232, and optionally alcohol 122 and acid catalyst 124 to produce a solution containing recycled PVOH and recycled acetal.

[0161] Without being bound by any particular theory, it is believed that the aldehyde scavenger 232 reacts with the converted butyraldehyde, thereby restricting its conversion back to PVB. That is, the aldehyde scavenger 232 reacts with butyraldehyde to produce an acetal (i.e., dioxane (1,3-dioxane, ethylene glycol acetal or ethylene glycol butyl acetal)), which is usually soluble in the reaction product together with the regenerated PVOH. Thus, the hydrolysis reaction is driven to produce 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 diols (e.g., ethylene glycol), propylene glycol, methanol, ethanol, and acetoacetate esters.

[0162] Thus, the mixture 234 contains water, PVOH, acetal, water-insoluble PVB, and / or a residual portion of one or more additional components. The concentration of water can 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% by weight of the mixture 234, between 80% and 99%, between 85% and 99%, between 90% and 99%, or between 95% and 99%.

[0163] The concentration of water-soluble PVOH can be less than 20%, less than 15%, less than 10%, less than 5%, less than 2%, less than 1%, or between 1% and 20%, between 1% and 15%, between 1% and 10%, or between 1% and 5% by weight of the mixture 234.

[0164] The concentration of acetal can be between 1% and 25%, between 1% and 20%, between 1% and 15%, or between 5% and 15% by weight of the mixture 234.

[0165] The concentration of water-insoluble PVB can be less than 25%, less than 20%, less than 15%, less than 10%, less than 5%, between 0% and 25%, between 1% and 25%, between 5% and 25%, or between 10% and 20% by weight of the mixture 234.

[0166] The concentration of the residual portion can be less than 20%, less than 15%, less than 10%, less than 5%, less than 2%, less than 1%, or between 1% and 20%, between 1% and 15%, between 1% and 10%, or between 1% and 5% by weight of the mixture 234.

[0167] The residual portion may include residual polyvinyl acetate (PVAC), residual alcohol, residual catalyst, butyraldehyde, and / or butyral acetal. The concentration of these residual portions may each be less than 5%, less than 2%, less than 1%, less than 0.5%, or less than 0.1% by weight of the mixture 234.

[0168] Reference Figure 11 , the mixture 234 may further comprise one or more insoluble components. Thus, the 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 at unit 148 to produce r-PVB 236.

[0169] At unit 148, optionally in the presence of an acid catalyst 124, the filtered and cooled mixture 234 is combined with water 150, fresh butyraldehyde 152, and fresh PVOH 154 to produce r-PVB 236 and a liquid product 238. The r-PVB 236 may be processed as described above. In one embodiment or in combination with any of the embodiments mentioned herein, the liquid product 238 contains acetal and water, which may be separated and processed in downstream units.

[0170] Now referring Figure 12 , once filtered and / or centrifuged, the mixture 234 can be processed to recover regenerated PVOH and regenerated acetal therefrom. Specifically, in the illustrated embodiment, a portion of the mixture 234 is directed to a stripping unit 250 where at least one of regenerated PVOH 252 or aldehyde scavenger 254 is stripped from the solution. The regenerated PVOH can be recovered and stored for use, for example, in the production of regenerated PVB, and the aldehyde scavenger 254 can be recovered for further use in the hydrolysis step. In addition, the regenerated acetal 256 can be recovered and stored for future use and / or processing.

[0171] In some embodiments, another portion of the mixture 234 is processed in a precipitation unit 260 and a liquid-liquid extraction unit 262 to recover regenerated PVOH and regenerated acetal therefrom. At the precipitation unit 260, the mixture 234 is combined with an alcohol 264 to precipitate regenerated PVOH 266 therefrom. The resulting liquid product 268 containing alcohol, water, and acetal is discharged from the precipitation unit 260 and received at the extraction unit 262. At the extraction unit 262, the liquid product 268 is combined with an extractant 270 (such as toluene) to recover water 272 and a liquid product 274 containing the extractant, alcohol, and acetal.

[0172] 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 can be directed to hydrolysis unit 286 and reacted with water 288 to produce a liquid product 290 comprising regenerated aldehyde 292 and alcohol 294, which can be recovered at distillation / separation unit 296. In some embodiments, regenerated aldehyde 292 can be directed to the PVOH acetalization unit for use in producing additional PVB.

[0173] Now referring Figure 13 and 14 , PVB 230 (e.g., dry PVB 114, PVB solution 130, off-spec PVB 184, or PVB solution 202) is directed to hydrolysis unit 298 and hydrolyzed as described above to produce a solution comprising a number of hydrolysis products in the form of recovered component products, which are directly derived from the PVB-containing composition. For example, as described above, the hydrolysis products can include several recovered component products derived from the hydrolysis of the PVB resin. In the illustrated embodiment, PVB 230 can 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 comprising regenerated PVOH and one or more butylimine derivatives.

[0174] Without being bound by any particular theory, it is believed that the amino-functional compound 300 reacts with the converted butyraldehyde, thereby restricting its conversion back to PVB. That is, the amino-functional compound 300 reacts with butyraldehyde to produce one or more butylimine derivatives. Accordingly, the hydrolysis reaction is driven to produce PVOH, and a mixture 302 comprising regenerated PVOH and one or more butylimine derivatives is produced therefrom.

[0175] Exemplary amino-functional compounds include, but are not limited to, monofunctional amines, bifunctional amines, aromatic amines, ethanolamine, methylamine, ethylamine, ethylenediamine, propylenediamine, butylamine, or aqueous ammonia. Accordingly, the resulting butylimine derivatives are based on the amino-functional compound used in unit 298. For example, the butylimine derivatives can be monofunctional (i.e., unsaturated) derivatives or bifunctional (i.e., saturated) derivatives. Exemplary monofunctional derivatives include, but are not limited to, imines and enamines. Exemplary bifunctional derivatives include, but are not limited to, oxazolidines and imidazolines.

[0176] Thus, mixture 302 contains water, PVOH, one or more butyl imine derivatives, water-insoluble PVB, and a residual portion of one or more additional components. The concentration of water can 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% by weight of mixture 302, between 80% and 99%, between 85% and 99%, between 90% and 99%, or between 95% and 99%.

[0177] The concentration of water-soluble PVOH can be less than 20%, less than 15%, less than 10%, less than 5%, less than 2%, less than 1%, or between 1% and 20%, between 1% and 15%, between 1% and 10%, or between 1% and 5% by weight of mixture 302.

[0178] The concentration of the butyl imine derivative can be between 1% and 25%, between 1% and 20%, between 1% and 15%, or between 5% and 15% by weight of mixture 302.

[0179] The concentration of water-insoluble PVB can be less than 25%, less than 20%, less than 15%, less than 10%, less than 5%, between 0% and 25%, between 1% and 25%, between 5% and 25%, or between 10% and 20% by weight of mixture 302.

[0180] The concentration of the residual portion can be less than 20%, less than 15%, less than 10%, less than 5%, less than 2%, less than 1%, or between 1% and 20%, between 1% and 15%, between 1% and 10%, or between 1% and 5% by weight of mixture 302.

[0181] The residual portion can include residual polyvinyl acetate (PVAC), residual alcohol, residual catalyst, butyraldehyde, and / or butyral. The concentration of these residual portions can each be less than 5%, less than 2%, less than 1%, less than 0.5%, or less than 0.1% by weight of mixture 302.

[0182] Reference Figure 13 Mixture 302 can also contain one or more insoluble components. Thus, mixture 302 can optionally be filtered in unit 138 and / or centrifuged in unit 140. The solution is cooled in unit 144 and then used at unit 148 to produce r-PVB 304.

[0183] At unit 148, optionally in the presence of acid catalyst 124, the filtered and cooled mixture 302 is combined with water 150, fresh butyraldehyde 152, and fresh PVOH 154 to produce r-PVB 304 and liquid product 306. The r-PVB 304 can be processed as described above. In one embodiment or in combination with any of the embodiments mentioned herein, the liquid product 306 contains one or more butylimine derivatives and water.

[0184] Now referring Figure 14 , once filtered and / or centrifuged, the mixture 302 can be processed to recover regenerated PVOH and one or more butylimine derivatives therefrom. Specifically, in the illustrated embodiment, the mixture 302 is processed in precipitation unit 260 to recover regenerated PVOH therefrom. At precipitation unit 260, the mixture 302 is combined with alcohol 264 to precipitate regenerated PVOH 314 therefrom. The resulting liquid product 316, which contains alcohol, water, and one or more butylimine derivatives, is discharged from precipitation unit 260 and can be recovered and / or further processed to recover the butylimine derivatives therefrom.

[0185] Now referring Figure 15 , PVB 230 (e.g., dry PVB 114, PVB solution 130, off-spec PVB 184, or PVB solution 202) is directed to hydrolysis unit 326 and hydrolyzed as described above to produce a mixture containing a number of hydrolysis products in the form of recycled component products, which are directly derived from the PVB-containing composition. For example, as described above, the hydrolysis products can contain several recycled component products derived from the hydrolysis of the PVB resin. In the illustrated embodiment, PVB 230 can 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 containing regenerated PVOH and regenerated butanol.

[0186] Without being bound by any particular theory, it is believed that hydrogen 328 and hydrogenation catalyst 330 react with the converted butyraldehyde, thereby restricting 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 is driven to produce PVOH, and a mixture 332 containing regenerated PVOH and regenerated butanol is produced therefrom.

[0187] Examples of hydrogenation catalysts include, but are not limited to, Group 8 metals (e.g., iron (Fe), ruthenium (Ru), osmium (Os), and (Hs)). The hydrogenation catalyst 330 can include one or more different hydrogenation catalysts. In addition, the hydrogenation catalyst 330 can be heterogeneous or homogeneous.

[0188] Thus, mixture 332 contains water, PVOH, butanol, water-insoluble PVB, and a residual portion of one or more additional components. The concentration of water can 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% by weight of mixture 332, between 80% and 99%, between 85% and 99%, between 90% and 99%, or between 95% and 99%.

[0189] The concentration of water-soluble PVOH can be less than 20%, less than 15%, less than 10%, less than 5%, less than 2%, less than 1%, or between 1% and 20%, between 1% and 15%, between 1% and 10%, or between 1% and 5% by weight of mixture 332.

[0190] The concentration of butanol can be between 1% and 25%, between 1% and 20%, between 1% and 15%, or between 5% and 15% by weight of mixture 332.

[0191] The concentration of water-insoluble PVB can be less than 25%, less than 20%, less than 15%, less than 10%, less than 5%, between 0% and 25%, between 1% and 25%, between 5% and 25%, or between 10% and 20% by weight of mixture 332.

[0192] The concentration of the residual portion can be less than 20%, less than 15%, less than 10%, less than 5%, less than 2%, less than 1%, or between 1% and 20%, between 1% and 15%, between 1% and 10%, or between 1% and 5% by weight of mixture 332.

[0193] The residual portion can include residual polyvinyl acetate (PVAC), residual alcohol, residual catalyst, butyraldehyde, and / or butacetal. The concentration of these residual portions can each be less than 5%, less than 2%, less than 1%, less than 0.5%, or less than 0.1% by weight of mixture 332.

[0194] In one embodiment or in combination with any of the embodiments mentioned herein, the hydrolysis at unit 326 is carried out in one of, for example, a continuous stirred tank reactor, a bubble column reactor, a fixed bed / trickle bed reactor, or an autoclave reactor. Thus, based on the type of reactor used for the hydrolysis step, mixture 332 can have different compositions.

[0195] For example, in one embodiment, mixture 332 comprises water, PVOH, butanol, hydrogen, and a hydrogenation catalyst. In such embodiments, mixture 332 is directed to a settling / separation unit 334 to recover a gas phase 336, a liquid phase 338, and a solid phase 340. Regenerated butanol and hydrogen can be recovered from the gas phase 336. Regenerated PVOH, regenerated butanol, and water can be recovered from the liquid phase 338. Regenerated butanol can be recovered from the liquid phase 338 by, for example, liquid-liquid extraction. The hydrogenation catalyst can be recovered from the solid phase 340.

[0196] Optionally, for example, in a fixed bed / trickle bed reactor, the hydrogenation catalyst 330 is retained within the reactor such that mixture 332 comprises water, PVOH, butanol, and hydrogen. In such embodiments, mixture 332 is directed to a settling / separation unit 334 to recover only the gas phase 336 and the liquid phase 338. Regenerated butanol and hydrogen can be recovered from the gas phase 336. Regenerated PVOH, regenerated butanol, and water can be recovered from the liquid phase 338.

[0197] In further numbered embodiments and sub - embodiments:

[0198] Embodiment A1. A method for recovering polyvinyl butyral (PVB), the method comprising: partially hydrolyzing a PVB feedstock 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.

[0199] A2. The method according to A1, wherein the partial hydrolysis of the PVB feedstock has a conversion of less than 90%, less than 80%, less than 70%, less than 60%, or less than 50%.

[0200] A3. The method according to A1 or A2, wherein the partial hydrolysis produces a slurry comprising water - insoluble PVB in water.

[0201] A4. The method according to any one of A1 - A3, wherein the partial hydrolysis of the PVB feedstock produces a slurry comprising from 25% to 75%, from 30% to 70%, from 35% to 65%, or from 40% to 60% by weight of water - insoluble PVB.

[0202] A5. The method according to any one of A1 - A4, wherein the partial hydrolysis of the PVB feedstock produces a slurry comprising more than 25%, more than 50%, more than 75%, from 25% to 75%, from 30% to 70%, from 35% to 65%, or from 40% to 60% by weight of water.

[0203] A6. The method according to any one of A1 - A5, wherein the water-insoluble PVB has a higher residual PVOH content than the PVB raw material.

[0204] A7. The method according to any one of A1 - A6, wherein the regenerated PVB has a lower residual PVOH content than the water-insoluble PVB.

[0205] A8. The method according to any one of A1 - A7, wherein the partial hydrolysis of the PVB raw material produces 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%.

[0206] A9. The method according to any one of A1 - A8, the method further comprising reacting the residual PVOH to produce the regenerated PVB having a residual PVOH content between 1% and 90%, between 5% and 30%, between 7% and 30%, or between 16% and 20%.

[0207] A10. The method according to any one of A1 - A9, the method further comprising reacting the residual PVOH to produce regenerated PVB having a target residual PVOH content, wherein the residual PVOH content of the PVB raw material is greater than the target residual PVOH content by more than 1%, more than 2%, more than 3%, more than 4%, more than 5%, or more than 10%.

[0208] A11. The method according to any one of A1 - A10, the method further comprising reacting the residual PVOH with fresh butyraldehyde to produce the regenerated PVB.

[0209] A12. The method according to any one of A1 - A11, the method further comprising performing the partial hydrolysis and reaction steps in a separation unit.

[0210] A13. The method according to any one of A1 - A12, the method further comprising performing the partial hydrolysis and reaction steps in the same unit.

[0211] A14. The method according to any one of A1 - A13, wherein the partial hydrolysis is carried out in the presence of an acid catalyst.

[0212] A15. The method according to A14, wherein the acid catalyst comprises at least one of organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0213] A16. The method according to A14 or A15, the method further comprising producing the recycled PVB in the presence of the same acid catalyst used in the partial hydrolysis step.

[0214] A17. The method according to any one of A1 - A16, wherein the partial hydrolysis is carried out at a temperature in the range between about 70 °C and about 250 °C.

[0215] A18. The method according to any one of A14 - A17, wherein when the hydrolysis step occurs in the presence of the acid catalyst, the partial hydrolysis is carried out at a temperature in the range between about 70 °C and about 150 °C.

[0216] A19. The method according to any one of A1 - A13 or A17, wherein when the hydrolysis step does not occur in the presence of an acid catalyst, the partial hydrolysis is carried out at a temperature in the range between about 150 °C and about 250 °C.

[0217] A20. The method according to any one of A1 - A19, wherein the partial hydrolysis is carried out in the presence of an alcohol.

[0218] A21. The method according to any one of A1 - A20, the method further comprising dissolving the PVB raw material in a solvent before the partial hydrolysis of the PVB raw material.

[0219] A22. The method according to any one of A20 and A21, the method further comprising dissolving the PVB raw material in a solvent containing the alcohol.

[0220] A23. The method according to any one of A1 - A22, the method further comprising recovering butyraldehyde produced by the partial hydrolysis of the PVB raw material.

[0221] A24. The method according to A23, the method further comprising producing the recycled PVB from the recovered butyraldehyde.

[0222] A25. The method according to any one of A1 - A24, the method further comprising: checking at least one of oversized dimensions, visible defects, compositional defects, gelation, or contamination of the recycled PVB; separating the PVB meeting the specifications from the PVB not meeting the specifications based on the check; and partially hydrolyzing the PVB not meeting the specifications to increase the residual PVOH content of the PVB not meeting the specifications.

[0223] A26. The method according to A25, the method further comprising reducing the size of the PVB not meeting the specifications before the partial hydrolysis of the PVB not meeting the specifications.

[0224] A27. The method according to any one of A25 or A26, the method further comprising reducing the size of the non - conforming PVB to an average particle size less than about 400 microns, 300 microns, or 200 microns or between about 200 microns and about 400 microns.

[0225] A28. The method according to any one of A1 - A27, the method further comprising reducing the size of the PVB raw material before said partial hydrolysis of the PVB raw material.

[0226] A29. The method according to any one of A1 - A28, the method further comprising reducing the size of the PVB raw material before said partial hydrolysis of the PVB raw material to an average particle size 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.

[0227] A30. The method according to any one of A1 - A29, wherein the PVB raw material comprises two or more PVB resins having different compositions from each other.

[0228] A31. The method according to any one of A1 - A30, wherein the PVB raw material comprises two or more PVB resins having different residual PVOH contents from each other.

[0229] A32. The method according to any one of A1 - A31, the method further comprising extracting a plasticizer from the PVB raw material before said partial hydrolysis of the PVB raw material.

[0230] A33. The method according to A32, the method further comprising extracting a plasticizer from the PVB raw material, the PVB raw material comprising a PVB source material derived from at least one post - industrial or post - consumer waste material.

[0231] A34. The method according to any one of A1 - A33, the method further comprising washing the PVB raw material to remove insoluble components before said partial hydrolysis of the PVB raw material.

[0232] A35. The method according to any one of A1 - A34, wherein the PVB raw material has a residual PVOH content of 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 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90%, and / or not more than 100%, not more than 90%, not more than 80%, not more than 70%, not more than 60%, not more than 50%, not more than 40%, not more than 35%, not more than 32%, not more than 30%, not more than 25%, not more than 22%, not more than 20%, not more than 19%, not more than 18%, not more than 17%, not more than 16%, not more than 15%, not more than 14%, not more than 13%, not more than 12%, not more than 11%, not more than 10%, not more than 9% or not more than 8%.

[0233] A36. The method according to any one of A1 - A35, wherein based on the total weight of the PVB raw material, the PVB raw material contains at least 1 phr, at least 5 phr, at least 10 phr, at least 15 phr, at least 20 phr, at least 25 phr, at least 30 phr, at least 35 phr, at least 40 phr, at least 45 phr, at least 50 phr, at least 55 phr, at least 60 phr, at least 65 phr, at least 70 phr, at least 75 phr, at least 80 phr, at least 85 phr or at least 90 phr, and / or not more than 100 phr, not more than 90 phr, not more than 85 phr, not more than 80 phr, not more than 75 phr, not more than 70 phr, not more than 65 phr, not more than 60 phr, not more than 55 phr, not more than 50 phr, not more than 45 phr, not more than 40 phr, not more than 35 phr, not more than 30 phr, not more than 25 phr, not more than 20 phr, not more than 15 phr or not more than 10 phr of a plasticizer.

[0234] A37. The method according to any one of A1 - A36, wherein the PVB raw material contains solid particles with 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.

[0235] A38. The method according to any one of A1 - A37, wherein based on the total weight of the PVB raw material, 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%, less than 1 wt% or less than 0.5 wt% of solid contaminants.

[0236] A39. The method according to any one of A1 - A38, wherein based on the total weight of the PVB raw material, 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 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.

[0237] A40. The method according to A39, wherein the insoluble components contain at least one polymer, wherein the polymer contains polyolefin, polyester, rubber, polyamide, polystyrene or a combination thereof, and wherein 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 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.

[0238] A41. The method according to 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.

[0239] A42. The method according to A39, wherein the insoluble component comprises glass, metal, salt, silicate, calcium, calcium derivative, sodium derivative 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 glass, metal, salt, silicate, calcium, calcium derivative, sodium derivative or a combination thereof.

[0240] A43. A method for recovering polyvinyl butyral (PVB), the method comprising: producing a plurality of PVB particles from fresh polyvinyl alcohol (PVOH) and fresh butyraldehyde in the presence of water; partially hydrolyzing a certain amount 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.

[0241] A44. The method according to 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%.

[0242] A45. The method according to any one of A43 and A44, wherein the partial hydrolysis produces a slurry of water-insoluble PVB in water.

[0243] A46. The method according to any one of A43 - A45, wherein partial hydrolysis of the PVB particles produces a slurry, the slurry comprising water-insoluble PVB in an amount between 25% and 75%, between 30% and 70%, between 35% and 65%, or between 40% and 60% by weight.

[0244] A47. The method according to any one of A43 - A46, wherein partial hydrolysis of the PVB particles produces a slurry, the slurry comprising water in an amount greater than 25%, greater than 50%, greater than 75%, between 25% and 75%, between 30% and 70%, between 35% and 65%, or between 40% and 60% by weight.

[0245] A48. The method according to any one of A43 - A47, wherein the water-insoluble PVB has a higher residual PVOH content than the PVB particles.

[0246] A49. The method according to any one of A43 - A48, wherein the regenerated PVB has a lower residual PVOH content than the water-insoluble PVB.

[0247] A50. The method according to any one of A43 - A49, wherein the partial hydrolysis of the PVB particles produces 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%.

[0248] A51. The method according to any one of A43 - A50, wherein the partial hydrolysis of the PVB particles produces the regenerated PVB having a residual PVOH content between 1% and 90%, between 5% and 30%, between 7% and 30%, or between 16% and 20%.

[0249] A52. The method according to any one of A43 - A51, the method further comprising reacting the residual PVOH to produce regenerated PVB having a target residual PVOH content, wherein the residual PVOH content of the PVB particles is greater than the target residual PVOH content of 1%, greater than 2%, greater than 3%, greater than 4%, greater than 5%, or greater than 10%.

[0250] A53. The method according to any one of A43 - A52, the method further comprising reacting the residual PVOH with fresh butyraldehyde to produce the regenerated PVB.

[0251] A54. The method according to any one of A43 - A53, the method further comprising performing the partial hydrolysis and reaction steps in a separation unit.

[0252] A55. The method according to any one of A43 - A54, the method further comprising performing the partial hydrolysis and reaction steps in the same unit.

[0253] A56. The method according to any one of A43 - A55, wherein the partial hydrolysis is carried out in the presence of an acid catalyst.

[0254] A57. The method according to A56, wherein the acid catalyst comprises at least one of organic sulfonic acid, nitric acid, sulfuric acid or hydrochloric acid.

[0255] A58. The method according to any one of A56 and A57, the method further comprising producing the regenerated PVB in the presence of the same acid catalyst used in the partial hydrolysis step.

[0256] A59. The method according to any one of A43 - A58, wherein the partial hydrolysis is carried out at a temperature in the range between about 70°C and about 250°C.

[0257] A60. The method according to any one of A56 - A59, wherein when the hydrolysis step occurs in the presence of the acid catalyst, the partial hydrolysis is carried out at a temperature in the range between about 70°C and about 150°C.

[0258] A61. The method according to any one of A43 - A55 and A59, wherein when the hydrolysis step does not occur in the presence of an acid catalyst, the partial hydrolysis is carried out at a temperature in the range between about 150°C and about 250°C.

[0259] A62. The method according to any one of A43 - A61, wherein the partial hydrolysis is carried out in the presence of an alcohol.

[0260] A63. The method according to any one of A43 - A62, the method further comprising dissolving the PVB particles in a solvent before the hydrolysis step.

[0261] A64. The method according to any one of A62 and A63, the method further comprising dissolving the PVB particles in a solvent containing the alcohol.

[0262] A65. The method according to any one of A43 - A64, the method further comprising recovering butyraldehyde produced by the partial hydrolysis of the PVB particles.

[0263] A66. The method according to A65, the method further comprising producing the recycled PVB from the recovered butyraldehyde.

[0264] A67. The method according to any one of A43 - A66, the method further comprising: inspecting at least one of oversized dimensions, visible defects, compositional defects, gelation, or contamination of the recycled PVB; separating the PVB meeting the specifications from the PVB not meeting the specifications based on the inspection; and partially hydrolyzing the PVB not meeting the specifications to increase the residual PVOH content of the PVB not meeting the specifications.

[0265] A68. The method according to A67, the method further comprising reducing the size of the PVB not meeting the specifications before the partial hydrolysis of the PVB not meeting the specifications.

[0266] A69. The method according to any one of A67 and A68, the method further comprising reducing the size of the PVB not meeting the specifications to an average particle size less than about 400 microns, 300 microns, or 200 microns or between about 200 microns and about 400 microns.

[0267] Embodiment B1. A method for recycling polyvinyl butyral (PVB), the method comprising: hydrolyzing a PVB raw material in the presence of hydrogen and a hydrogenation catalyst to produce a solution containing recycled polyvinyl alcohol (PVOH) and recycled butanol.

[0268] B2. The method according to B1, wherein the hydrogenation catalyst comprises at least one Group 8 metal.

[0269] B3. The method according to any one of B1 and B2, wherein the hydrogenation catalyst is heterogeneous or homogeneous.

[0270] B4. The method according to any one 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.

[0271] B5. The method according to any one of B1 - B4, the method further comprising recovering at least one of the recycled PVOH, the recycled butanol, and the hydrogenation catalyst from the solution.

[0272] B6. The method according to any one of B1 - B5, wherein the recovery comprises separating the solution into at least two of a gas phase, a liquid phase, and a solid phase.

[0273] B7. The method according to B6, wherein the recovery recovers the recycled PVOH from the liquid phase.

[0274] B8. The method according to any one of B6 and B7, wherein the recycling recovers the regenerated butanol from at least one of the gas phase or the liquid phase.

[0275] B9. The method according to any one of B6 - B8, wherein the recycling recovers the hydrogenation catalyst from the solid phase.

[0276] B10. The method according to any one of B1 - B9, further comprising reacting the regenerated PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce regenerated PVB.

[0277] B11. The method according to any one of B1 - B10, further comprising cooling the regenerated PVOH before the reaction step.

[0278] B12. The method according to any one of B1 - B11, wherein the hydrolysis is carried out at a pressure in the range between about 10 psia and about 2000 psia.

[0279] B13. The method according to any one of B1 - B12, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0280] B14. The method according to B13, wherein the acid catalyst comprises at least one of organic sulfonic acid, nitric acid, sulfuric acid or hydrochloric acid.

[0281] B15. The method according to any one of B13 and B14, further comprising producing the regenerated PVB in the presence of the same acid catalyst used in the hydrolysis step.

[0282] B16. The method according to any one of B1 - B15, wherein the hydrolysis is carried out at a temperature in the range between about 70 °C and about 250 °C.

[0283] B17. The method according to any one 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 between about 70 °C and about 150 °C.

[0284] B18. The method according to any one of B1 - B12 and B16, wherein when the hydrolysis step does not occur in the presence of an acid catalyst, the hydrolysis is carried out at a temperature in the range between about 150 °C and about 250 °C.

[0285] B19. The method according to any one of B1 - B18, wherein the hydrolysis of the PVB raw material is carried out in the presence of an alcohol.

[0286] B20. The method according to any one of B1 - B19, further comprising dissolving the PVB raw material in a solvent before the hydrolysis step.

[0287] B21. The method according to any one of B19 and B20, further comprising dissolving the PVB raw material in a solvent containing the alcohol.

[0288] B22. The method according to any one of B1 - B21, further comprising: checking for at least one of oversized size, visible defects, compositional defects, gelation, or contamination of the recycled PVB; separating the PVB meeting the specifications from the PVB not meeting the specifications based on the check; and hydrolyzing the PVB not meeting the specifications to produce additional recycled PVOH and recycled butanol.

[0289] B23. The method according to B22, further comprising reducing the size of the PVB not meeting the specifications before the hydrolysis of the PVB not meeting the specifications.

[0290] B24. The method according to any one of B22 and B23, further comprising reducing the size of the PVB not meeting the specifications to an average particle size less than about 400 microns, 300 microns, or 200 microns, or between about 200 microns and about 400 microns.

[0291] B25. The method according to any one of B1 - B24, further comprising reducing the size of the PVB raw material before the hydrolysis step.

[0292] B26. The method according to any one of B1 - B25, further comprising reducing the size of the PVB raw material to an average particle size 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 before the hydrolysis step.

[0293] B27. The method according to any one of B1 - B26, wherein the PVB raw material comprises two or more PVB resins having different compositions from each other.

[0294] B28. The method according to any one of B1 - B27, wherein the PVB raw material comprises two or more PVB resins having different residual PVOH contents from each other.

[0295] B29. The method according to any one of B1 - B28, further comprising extracting a plasticizer from the PVB raw material before the hydrolysis of the PVB raw material.

[0296] B30. The method according to B29, the method further comprising extracting a plasticizer from the PVB raw material, the PVB raw material comprising a PVB source material derived from at least one post-industrial recycled or post-consumer recycled material.

[0297] B31. The method according to any one of B1 - B30, the method further comprising washing the PVB raw material before the hydrolysis of the PVB raw material to remove insoluble components from the PVB raw material.

[0298] B32. The method according to any one of B1 - B31, the method further comprising centrifuging the solution to remove one or more insoluble components from the solution.

[0299] B33. The method according to any one of B1 - B32, the method further comprising filtering the solution to remove one or more insoluble components from the solution.

[0300] B34. The method according to any one of B32 and B33, the method further comprising centrifuging the solution before the filtering step.

[0301] B35. The method according to any one of B1 - B34, wherein the PVB raw material has a residual PVOH content of 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 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90%, and / or not more than 100%, not more than 90%, not more than 80%, not more than 70%, not more than 60%, not more than 50%, not more than 40%, not more than 35%, not more than 32%, not more than 30%, not more than 25%, not more than 22%, not more than 20%, not more than 19%, not more than 18%, not more than 17%, not more than 16%, not more than 15%, not more than 14%, not more than 13%, not more than 12%, not more than 11%, not more than 10%, not more than 9% or not more than 8%.

[0302] B36. The method according to any one of B1 - B35, wherein based on the total weight of the PVB raw material, the PVB raw material contains at least 1 phr, at least 5 phr, at least 10 phr, at least 15 phr, at least 20 phr, at least 25 phr, at least 30 phr, at least 35 phr, at least 40 phr, at least 45 phr, at least 50 phr, at least 55 phr, at least 60 phr, at least 65 phr, at least 70 phr, at least 75 phr, at least 80 phr, at least 85 phr or at least 90 phr, and / or not more than 100 phr, not more than 90 phr, not more than 85 phr, not more than 80 phr, not more than 75 phr, not more than 70 phr, not more than 65 phr, not more than 60 phr, not more than 55 phr, not more than 50 phr, not more than 45 phr, not more than 40 phr, not more than 35 phr, not more than 30 phr, not more than 25 phr, not more than 20 phr, not more than 15 phr or not more than 10 phr of a plasticizer.

[0303] B37. The method according to any one of B1 - B36, wherein the PVB raw material contains solid particles having an average particle size of at least 0.01 inch, at least 0.05 inch, at least 0.1 inch, at least 0.2 inch, at least 0.3 inch, at least 0.4 inch, at least 0.5 inch, at least 1 inch or at least 2 inches.

[0304] B38. The method according to any one of B - B37, wherein based on the total weight of the PVB raw material, 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.

[0305] B39. The method according to any one of B1 - B38, wherein based on the total weight of the PVB raw material, 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 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.

[0306] B40. The method according to B39, wherein the insoluble component comprises at least one polymer, wherein the polymer comprises a polyolefin, a polyester, a rubber, a polyamide, a polystyrene or a combination thereof, and 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 the polymer.

[0307] B41. The method according to B39, wherein the insoluble component comprises a 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.

[0308] B42. The method according to B39, wherein the insoluble component comprises glass, metal, salt, silicate, calcium, calcium derivative, sodium derivative, 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 glass, metal, salt, silicate, calcium, calcium derivative, sodium derivative, or a combination thereof.

[0309] B43. A method for recovering polyvinyl butyral (PVB), the method comprising: producing a plurality of PVB particles from fresh polyvinyl alcohol (PVOH) and fresh butyraldehyde in the presence of water; hydrolyzing a certain amount 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.

[0310] B44. The method according to B43, wherein the hydrogenation catalyst comprises at least one Group 8 metal.

[0311] B45. The method according to any one of B43 and B44, wherein the hydrogenation catalyst is heterogeneous or homogeneous.

[0312] B46. The method according to any one 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.

[0313] B47. The method according to any one of B43 - B46, the method further comprising recovering at least one of the regenerated PVOH, the regenerated butanol, and the hydrogenation catalyst from the solution.

[0314] B48. The method according to any one of B43 - B47, wherein the recovery comprises separating the solution into at least two of a gas phase, a liquid phase, and a solid phase.

[0315] B49. The method according to B48, wherein the recovery recovers the regenerated PVOH from the liquid phase.

[0316] B50. The method according to any one of B48 and B49, wherein the recovery recovers the regenerated butanol from at least one of the gas phase or the liquid phase.

[0317] B51. The method according to any one of B48 - B50, wherein the recovery recovers the hydrogenation catalyst from the solid phase.

[0318] B52. The method according to any one of B43 - B51, the method further comprising reacting the regenerated PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce regenerated PVB.

[0319] B53. The method according to any one of B43 - B52, the method further comprising cooling the regenerated PVOH before the reaction step.

[0320] B54. The method according to any one of B43 - B53, wherein the hydrolysis is carried out at a pressure in the range between about 10 psia and about 2000 psia.

[0321] B55. The method according to any one of B43 - B54, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0322] B56. The method according to B55, wherein the acid catalyst comprises at least one of organic sulfonic acid, nitric acid, sulfuric acid or hydrochloric acid.

[0323] B57. The method according to any one of B55 and B56, the method further comprising producing the regenerated PVB in the presence of the same acid catalyst used in the hydrolysis step.

[0324] B58. The method according to any one of B43 - B57, wherein the hydrolysis is carried out at a temperature in the range between about 100 °C and about 250 °C.

[0325] B59. The method according to any one of B43 - B58, wherein when the hydrolysis step occurs in the presence of the acid catalyst, the hydrolysis is carried out at a temperature in the range between about 100 °C and about 150 °C.

[0326] B60. The method according to any one of B43 - B54 and B58, wherein when the hydrolysis step does not occur in the presence of an acid catalyst, the hydrolysis is carried out at a temperature in the range between about 150 °C and about 250 °C.

[0327] B61. The method according to any one of B43 - B60, wherein the hydrolysis of the PVB particles is carried out in the presence of an alcohol.

[0328] B62. The method according to any one of B43 - B61, the method further comprising dissolving the PVB particles in a solvent before the hydrolysis step.

[0329] B63. The method according to any one of B61 and B62, the method further comprising dissolving the PVB particles in a solvent containing the alcohol.

[0330] B64. The method according to any one of B43 - B63, the method further comprising: checking for at least one of oversized size, visible defects, compositional defects, gelation, or contamination of the recycled PVB; separating the PVB meeting the specifications from the PVB not meeting the specifications based on the check; and hydrolyzing the PVB not meeting the specifications to produce additional recycled PVOH and recycled butanol.

[0331] B65. The method according to B64, the method further comprising reducing the size of the PVB not meeting the specifications before the hydrolysis of the PVB not meeting the specifications.

[0332] B66. The method according to any one of B64 and B65, the method further comprising reducing the size of the PVB not meeting the specifications to an average particle size less than about 400 microns, 300 microns, or 200 microns or between about 200 microns and about 400 microns.

[0333] Embodiment C1. A method for recycling polyvinyl butyral (PVB), the method comprising: hydrolyzing a PVB raw material in the presence of an aldehyde scavenger to produce a solution containing recycled polyvinyl alcohol (PVOH) and recycled acetal.

[0334] C2. The method according to C1, wherein the aldehyde scavenger comprises at least one of a C2 diol, propylene glycol, methanol, ethanol, or acetoacetate.

[0335] C3. The method according to any one of C1 and C2, the method further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVB.

[0336] C4. The method according to any one of C1 - C3, the method further comprising cooling the recycled PVOH before the reaction step.

[0337] C5. The method according to any one of C1 - C4, the method further comprising: reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce the recycled PVB and a first liquid product; and recovering the first liquid product containing the recycled acetal.

[0338] C6. The method according to any one of C1-C5, the method further comprising stripping at least one of the regenerated PVOH or aldehyde scavenger from the solution.

[0339] C7. The method according to any one of C1-C6, wherein the hydrolysis is carried out in the presence of the regenerated solvent.

[0340] C8. The method according to any one of C1-C7, the method further comprising precipitating the regenerated PVOH from the solution in the presence of an alcohol.

[0341] C9. The method according to C8, wherein recovering the regenerated acetal comprises at least one of liquid-liquid extraction or distillation of a second liquid product.

[0342] C10. The method according to any one of C1-C9, the method further comprising hydrolyzing the recovered regenerated acetal to produce a regenerated aldehyde.

[0343] C11. The method according to any one of C1-C10, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0344] C12. The method according to C11, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0345] C13. The method according to any one of C11 and C12, the method further comprising producing the regenerated PVB in the presence of the same acid catalyst used in the hydrolysis step.

[0346] C14. The method according to any one of C1-C13, wherein the hydrolysis is carried out at a temperature in the range of about 70 °C to about 250 °C.

[0347] C15. The method according to any one of C11-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.

[0348] C16. The method according to any one of C1-C10 and C14, wherein when the hydrolysis step does not occur in the presence of an acid catalyst, the hydrolysis is carried out at a temperature in the range of about 150 °C to about 250 °C.

[0349] C17. The method according to any one of C1-C16, wherein the hydrolysis of the PVB raw material is carried out in the presence of an alcohol.

[0350] C18. The method according to any one of C1-C17, the method further comprising dissolving the PVB raw material in a solvent before the hydrolysis of the PVB raw material.

[0351] C19. The method according to any one of C17 and C18, the method further comprising dissolving the PVB raw material in a solvent containing the alcohol.

[0352] C20. The method according to any one of C1-C19, the method further comprising: checking for at least one of oversized dimensions, visible defects, compositional defects, gelation, or contamination of the recycled PVB; separating the PVB meeting the specifications from the PVB not meeting the specifications based on the check; and hydrolyzing the PVB not meeting the specifications to produce additional recycled PVOH.

[0353] C21. The method according to C20, the method further comprising reducing the size of the PVB not meeting the specifications before the hydrolysis of the PVB not meeting the specifications.

[0354] C22. The method according to any one of C20 and C21, the method further comprising reducing the size of the PVB not meeting the specifications to an average particle size less than about 400 microns, 300 microns, or 200 microns or between about 200 microns and about 400 microns.

[0355] C23. The method according to any one of C1-C22, the method further comprising reducing the size of the PVB raw material before the hydrolysis step.

[0356] C24. The method according to any one of C1-C23, the method further comprising reducing the size of the PVB raw material before the hydrolysis step to an average particle size 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.

[0357] C25. The method according to any one of C1-C24, wherein the PVB raw material comprises two or more PVB resins having different compositions from each other.

[0358] C26. The method according to any one of C1-C25, wherein the PVB raw material comprises two or more PVB resins having different residual PVOH contents from each other.

[0359] C27. The method according to any one of C1-C26, the method further comprising extracting a plasticizer from the PVB raw material before the hydrolysis of the PVB raw material.

[0360] C28. The method according to C27, the method further comprising extracting a plasticizer from the PVB raw material, the PVB raw material comprising a PVB source material derived from at least one post-industrial or post-consumer recycled material.

[0361] C29. The method according to any one of C1 - C28, the method further comprising washing the PVB raw material before the hydrolysis of the PVB raw material to remove insoluble components from the PVB raw material.

[0362] C30. The method according to any one of C1 - C29, the method further comprising centrifuging the solution to remove one or more insoluble components from the solution.

[0363] C31. The method according to any one of C1 - C30, the method further comprising filtering the solution to remove one or more insoluble components from the solution.

[0364] C32. The method according to any one of C30 and C31, the method further comprising centrifuging the solution before the filtering of the solution.

[0365] C33. The method according to any one of C1 - C32, the method further comprising recovering and storing the regenerated PVOH from the solution.

[0366] C34. The method according to any one of C1 - C33, wherein the PVB raw material has a residual PVOH content of 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 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90%, and / or not more than 100%, not more than 90%, not more than 80%, not more than 70%, not more than 60%, not more than 50%, not more than 40%, not more than 35%, not more than 32%, not more than 30%, not more than 25%, not more than 22%, not more than 20%, not more than 19%, not more than 18%, not more than 17%, not more than 16%, not more than 15%, not more than 14%, not more than 13%, not more than 12%, not more than 11%, not more than 10%, not more than 9% or not more than 8%.

[0367] C35. The method according to any one of C1 - C34, wherein based on the total weight of the PVB raw material, the PVB raw material contains at least 1 phr, at least 5 phr, at least 10 phr, at least 15 phr, at least 20 phr, at least 25 phr, at least 30 phr, at least 35 phr, at least 40 phr, at least 45 phr, at least 50 phr, at least 55 phr, at least 60 phr, at least 65 phr, at least 70 phr, at least 75 phr, at least 80 phr, at least 85 phr or at least 90 phr, and / or not more than 100 phr, not more than 90 phr, not more than 85 phr, not more than 80 phr, not more than 75 phr, not more than 70 phr, not more than 65 phr, not more than 60 phr, not more than 55 phr, not more than 50 phr, not more than 45 phr, not more than 40 phr, not more than 35 phr, not more than 30 phr, not more than 25 phr, not more than 20 phr, not more than 15 phr or not more than 10 phr of a plasticizer.

[0368] C36. The method according to any one of C1 - C35, wherein the PVB raw material contains solid particles having an average particle size of at least 0.01 inch, at least 0.05 inch, at least 0.1 inch, at least 0.2 inch, at least 0.3 inch, at least 0.4 inch, at least 0.5 inch, at least 1 inch or at least 2 inches.

[0369] C37. The method according to any one of C1 - C36, wherein based on the total weight of the PVB raw material, 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.

[0370] C38. The method according to any one of C1 - C37, wherein based on the total weight of the PVB raw material, 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 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.

[0371] C39. The method according to C38, wherein the insoluble component comprises at least one polymer, wherein the polymer comprises polyolefin, polyester, rubber, polyamide, polystyrene, or a combination thereof, and 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 the polymer.

[0372] C40. The method according to 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.

[0373] C41. The method according to C38, wherein the insoluble component comprises glass, metal, salt, silicate, calcium, calcium derivative, sodium derivative, 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 glass, metal, salt, silicate, calcium, calcium derivative, sodium derivative, or a combination thereof.

[0374] C42. A method for recycling polyvinyl butyral (PVB), the method comprising: producing a plurality of PVB particles from fresh polyvinyl alcohol and fresh butyraldehyde in the presence of water; hydrolyzing a certain amount 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.

[0375] C43. The method according to C42, wherein the aldehyde scavenger comprises at least one of C2 diol, propylene glycol, methanol, ethanol, or acetoacetate.

[0376] C44. The method according to any one of C42 and C43, the method further comprising reacting the regenerated PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce regenerated PVB.

[0377] C45. The method according to any one of C42 - C44, the method further comprising cooling the regenerated PVOH before the reaction step.

[0378] C46. The method according to any one of C42 - C45, the method further comprising: reacting the regenerated PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce the regenerated PVB and a first liquid product; and recovering the first liquid product containing the regenerated acetal.

[0379] C47. The method according to any one of C42 - C46, the method further comprising stripping at least one of the regenerated PVOH or the aldehyde scavenger from the solution.

[0380] C48. The method according to any one of C42 - C47, wherein the hydrolysis is carried out in the presence of the regenerated solvent.

[0381] C49. The method according to any one of C42 - C48, the method further comprising precipitating the regenerated PVOH from the solution in the presence of an alcohol.

[0382] C50. The method according to C49, wherein recovering the regenerated acetal comprises at least one of liquid - liquid extraction or distillation of a second liquid product.

[0383] C51. The method according to any one of C42 - C50, the method further comprising hydrolyzing the recovered regenerated acetal to produce a regenerated aldehyde.

[0384] C52. The method according to any one of C42 - C51, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0385] C53. The method according to C52, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0386] C54. The method according to any one of C52 and C53, the method further comprising producing the regenerated PVB in the presence of the same acid catalyst used in the hydrolysis of the PVB particles.

[0387] C55. The method according to any one of C42 - C54, wherein the hydrolysis is carried out at a temperature in the range of about 70 °C to about 250 °C.

[0388] C56. The method according to any one of C52 - 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.

[0389] C57. The method according to any one of C42 - C51 and C55, wherein when the hydrolysis step does not occur in the presence of an acid catalyst, the hydrolysis is carried out at a temperature in the range of about 150 °C to about 250 °C.

[0390] C58. The method according to any one of C42 - C57, wherein the hydrolysis of the PVB particles is carried out in the presence of an alcohol.

[0391] C59. The method according to any one of C42 - C58, the method further comprising dissolving the PVB particles in a solvent before the hydrolysis step.

[0392] C60. The method according to any one of C58 and C59, the method further comprising dissolving the PVB particles in a solvent containing the alcohol.

[0393] C61. The method according to any one of C42 - C60, the method further comprising: checking for at least one of oversized size, visible defects, compositional defects, gelation, or contamination of the recycled PVB; separating the PVB meeting the specifications from the PVB not meeting the specifications based on the checking; and hydrolyzing the PVB not meeting the specifications to produce additional recycled PVOH.

[0394] C62. The method according to C61, the method further comprising reducing the size of the PVB not meeting the specifications before the hydrolysis of the PVB not meeting the specifications.

[0395] C63. The method according to any one of C61 and C62, the method further comprising reducing the size of the PVB not meeting the specifications to an average particle size less than about 400 microns, 300 microns, or 200 microns or between about 200 microns and about 400 microns.

[0396] C64. The method according to any one of C42 - C63, the method further comprising recovering and storing the recycled PVOH from the solution.

[0397] Embodiment D1. A method for recovering polyvinyl butyral (PVB), the method comprising: hydrolyzing a PVB feedstock in the presence of at least one amino-functional compound to produce a solution containing recycled polyvinyl alcohol (PVOH) and one or more butylimine derivatives.

[0398] D2. The method according to D1, wherein the at least one amino-functional compound comprises at least one of a monofunctional amine, a bifunctional amine, an aromatic amine, ethanolamine, methylamine, ethylamine, ethylenediamine, propylenediamine, butylamine, or ammonia water.

[0399] D3. The method according to any one of D1 and D2, the method further comprising reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce recycled PVB.

[0400] D4. The method according to any one of D1 - D3, the method further comprising cooling the recycled PVOH before the reaction step.

[0401] D5. The method according to any one of D1 - D4, the method further comprising: reacting the recycled PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce the recycled PVB and a first liquid product; and recovering the first liquid product containing the one or more butylimine derivatives.

[0402] D6. The method according to any one of D1 - D5, the method further comprising precipitating the regenerated PVOH from the solution in the presence of an alcohol.

[0403] D7. The method according to any one of D1 - D6, the method 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.

[0404] D8. The method according to 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.

[0405] D9. The method according to any one of D1 - D8, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0406] D10. The method according to D9, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0407] D11. The method according to any one of D9 and D10, the method further comprising producing the regenerated PVB in the presence of the same acid catalyst used in the hydrolysis of the PVB raw material.

[0408] D12. The method according to any one of D1 - D11, wherein the hydrolysis is carried out at a temperature in the range between about 70°C and about 250°C.

[0409] D13. The method according to any one 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 between about 70°C and about 150°C.

[0410] D14. The method according to any one of D1 - D8 and D12, wherein when the hydrolysis step does not occur in the presence of an acid catalyst, the hydrolysis is carried out at a temperature in the range between about 150°C and about 250°C.

[0411] D15. The method according to any one of D1 - D14, wherein the hydrolysis of the PVB raw material is carried out in the presence of an alcohol.

[0412] D16. The method according to any one of D1 - D15, the method further comprising dissolving the PVB raw material in a solvent before the hydrolysis step.

[0413] D17. The method according to any one of D14 and D15, the method further comprising dissolving the PVB raw material in a solvent comprising the alcohol.

[0414] D18. The method according to any one of D1 - D17, the method further comprising: inspecting at least one of oversized dimensions, visible defects, compositional defects, gelation, or contamination of the recycled PVB; separating the PVB meeting the specifications from the PVB not meeting the specifications based on the inspection; and hydrolyzing the PVB not meeting the specifications to produce additional recycled PVOH.

[0415] D19. The method according to D18, the method further comprising reducing the size of the PVB not meeting the specifications before the hydrolysis of the PVB not meeting the specifications.

[0416] D20. The method according to any one of D18 and D19, the method further comprising reducing the size of the PVB not meeting the specifications to an average particle size less than about 400 microns, 300 microns, or 200 microns or between about 200 microns and about 400 microns.

[0417] D21. The method according to any one of D1 - D20, the method further comprising reducing the size of the PVB raw material before the hydrolysis step.

[0418] D22. The method according to any one of D1 - D21, the method further comprising reducing the size of the PVB raw material to an average particle size 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 before the hydrolysis step.

[0419] D23. The method according to any one of D1 - D22, wherein the PVB raw material comprises two or more PVB resins having different compositions from each other.

[0420] D24. The method according to any one of D1 - D23, wherein the PVB raw material comprises two or more PVB resins having different residual PVOH contents from each other.

[0421] D25. The method according to any one of D1 - D24, the method further comprising extracting a plasticizer from the PVB raw material before the hydrolysis of the PVB raw material.

[0422] D26. The method according to D25, the method further comprising extracting a plasticizer from the PVB raw material, the PVB raw material comprising at least one industrially post - recycled or post - consumer recycled material PVB source material.

[0423] D27. The method according to any one of D1 - D26, the method further comprising washing the PVB raw material before the hydrolysis of the PVB raw material to remove insoluble components from the PVB raw material.

[0424] D28. The method according to any one of D1 - D27, the method further comprising centrifuging the solution to remove one or more insoluble components from the solution.

[0425] D29. The method according to any one of D1 - D28, the method further comprising filtering the solution to remove one or more insoluble components from the solution.

[0426] D30. The method according to any one of D28 and D29, the method further comprising centrifuging the solution before the filtering step.

[0427] D31. The method according to any one of D1 - D30, the method further comprising recovering and storing the regenerated PVOH from the solution.

[0428] D32. The method according to any one of D1 - D31, wherein the PVB raw material has a residual PVOH content of 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 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90%, and / or not more than 100%, not more than 90%, not more than 80%, not more than 70%, not more than 60%, not more than 50%, not more than 40%, not more than 35%, not more than 32%, not more than 30%, not more than 25%, not more than 22%, not more than 20%, not more than 19%, not more than 18%, not more than 17%, not more than 16%, not more than 15%, not more than 14%, not more than 13%, not more than 12%, not more than 11%, not more than 10%, not more than 9% or not more than 8%.

[0429] D33. The method according to any one of D1 - D32, wherein based on the total weight of the PVB raw material, the PVB raw material contains at least 1 phr, at least 5 phr, at least 10 phr, at least 15 phr, at least 20 phr, at least 25 phr, at least 30 phr, at least 35 phr, at least 40 phr, at least 45 phr, at least 50 phr, at least 55 phr, at least 60 phr, at least 65 phr, at least 70 phr, at least 75 phr, at least 80 phr, at least 85 phr or at least 90 phr, and / or not more than 100 phr, not more than 90 phr, not more than 85 phr, not more than 80 phr, not more than 75 phr, not more than 70 phr, not more than 65 phr, not more than 60 phr, not more than 55 phr, not more than 50 phr, not more than 45 phr, not more than 40 phr, not more than 35 phr, not more than 30 phr, not more than 25 phr, not more than 20 phr, not more than 15 phr or not more than 10 phr of a plasticizer.

[0430] D34. The method according to any one of D1 - D33, wherein the PVB raw material contains 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.

[0431] D35. The method according to any one of D1 - D34, wherein based on the total weight of the PVB raw material, 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.

[0432] D36. The method according to any one of D1 - D35, wherein based on the total weight of the PVB raw material, 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 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.

[0433] D37. The method according to D36, wherein the insoluble component comprises at least one polymer, wherein the polymer comprises polyolefin, polyester, rubber, polyamide, polystyrene or a combination thereof, and 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 the polymer.

[0434] D38. The method according to 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.

[0435] D39. The method according to D36, wherein the insoluble component comprises glass, metal, salt, silicate, calcium, calcium derivative, sodium derivative, 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 glass, metal, salt, silicate, calcium, calcium derivative, sodium derivative, or a combination thereof.

[0436] D40. A method for recycling polyvinyl butyral (PVB), the method comprising: producing a plurality of PVB particles from fresh polyvinyl alcohol and fresh butyraldehyde in the presence of water; hydrolyzing a certain amount of 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.

[0437] D41. The method according to D40, wherein the at least one amino-functional compound comprises at least one of a monofunctional amine, a bifunctional amine, an aromatic amine, ethanolamine, methylamine, ethylamine, ethylenediamine, propylenediamine, butylamine, or ammonia water.

[0438] D42. The method according to any one of D40 and D41, the method further comprising reacting the regenerated PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce regenerated PVB.

[0439] D43. The method according to any one of D40-D42, the method further comprising cooling the regenerated PVOH before the reaction step.

[0440] D44. The method according to any one of D40-D43, the method further comprising: reacting the regenerated PVOH with at least one of fresh butyraldehyde or fresh PVOH to produce the regenerated PVB and a first liquid product; and recovering the first liquid product comprising the one or more butylimine derivatives.

[0441] D45. The method according to any one of D40-D44, the method further comprising precipitating the regenerated PVOH from the solution in the presence of an alcohol.

[0442] D46. The method according to any one of D40 - D45, the method further comprising: recovering a second liquid product separated from the precipitated PVOH; and recovering the one or more butyl imine derivatives from the second liquid product.

[0443] D47. The method according to D46, wherein recovering the one or more butyl imine derivatives comprises performing at least one of liquid - liquid extraction or distillation on the second liquid product.

[0444] D48. The method according to any one of D40 - D47, wherein the hydrolysis is carried out in the presence of an acid catalyst.

[0445] D49. The method according to D48, wherein the acid catalyst comprises at least one of an organic sulfonic acid, nitric acid, sulfuric acid, or hydrochloric acid.

[0446] D50. The method according to any one of D48 and D49, the method further comprising producing the regenerated PVB in the presence of the same acid catalyst used in the hydrolysis of the PVB particles.

[0447] D51. The method according to any one of D40 - D50, wherein the hydrolysis is carried out at a temperature in the range between about 70 °C and about 250 °C.

[0448] D52. The method according to any one 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 between about 70 °C and about 150 °C.

[0449] D53. The method according to any one of D40 - D47 and D51, wherein when the hydrolysis step does not occur in the presence of an acid catalyst, the hydrolysis is carried out at a temperature in the range between about 150 °C and about 250 °C.

[0450] D54. The method according to any one of D40 - D53, wherein the hydrolysis of the PVB particles is carried out in the presence of an alcohol.

[0451] D55. The method according to any one of D40 - D54, the method further comprising dissolving the PVB particles in a solvent before the hydrolysis step.

[0452] D56. The method according to any one of D54 and D55, the method further comprising dissolving the PVB particles in a solvent comprising the alcohol.

[0453] D57. The method according to any one of D40 - D56, the method further comprising: checking for at least one of oversized size, visible defects, compositional defects, gelation, or contamination of the recycled PVB; separating the PVB meeting the specifications from the non - conforming PVB based on the checking; and hydrolyzing the non - conforming PVB to produce additional recycled PVOH.

[0454] D58. The method according to D57, the method further comprising reducing the size of the non - conforming PVB before the hydrolysis of the non - conforming PVB.

[0455] D59. The method according to any one of D57 and D58, the method further comprising reducing the size of the non - conforming PVB to an average particle size less than about 400 microns, 300 microns, or 200 microns or between about 200 microns and about 400 microns.

[0456] D60. The method according to any one of D40 - D59, the method further comprising recovering and storing the recycled PVOH from the solution.

[0457] After reading the disclosure herein, additional advantages of the various embodiments will be apparent to those skilled in the art. It should be understood that, unless otherwise indicated herein, the various embodiments described herein are not necessarily mutually exclusive. For example, a feature described or depicted in one embodiment may also be included in other embodiments, but not necessarily in other embodiments. Thus, the present disclosure encompasses various combinations and / or integrations of the specific embodiments described herein.

[0458] Examples

[0459] Example 1: A three - liter Parr reactor was charged with 15 parts of a PVB resin of 18.7% PVOH, 0.25 part 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 found to contain 0.94% total solids.

[0460] Example 2: A one - liter three - necked jacketed glass reactor was charged with 10 parts of a PVB resin of 18.7% PVOH, 1000 parts of water, and 14.2 parts of 70 wt% nitric acid, while stirring at 300 rpm. 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 a PVB resin of 47% PVOH were obtained.

[0461] Example 3: Charge 40 parts of PVB resin with 18.7% PVOH, 1000 parts of water, and 14.2 parts of 70 wt% nitric acid into a one-liter three-necked jacketed glass reactor, while stirring at 300 rpm. Heat the mixture to 90 °C and hold for 6 hours. Cool the resulting suspension to room temperature and neutralize to pH 7 with 8.83 parts of KOH. After filtration and drying, 36 parts of PVB resin with 35.1% PVOH are obtained.

[0462] Example 4: Charge 10 parts of PVB resin with 18.7% PVOH, 1000 parts of water, and 14.2 parts of 70 wt% nitric acid into a one-liter three-necked jacketed glass reactor, while stirring at 300 rpm. Heat the mixture to 85 °C and hold for 12.5 hours. Cool the resulting clear solution to room temperature and neutralize to pH 7 with 8.83 parts of KOH. Place the solution in an aluminum tray and dry in an oven at 45 °C for two days to obtain a film. Wash the film with water to remove salts, and 7 parts of dry PVOH are obtained.

[0463] Example 5: Charge 20 parts of PVB resin with 18.7% PVOH, 1000 parts of water, 0.16 parts of EDTA, and 14.2 parts of 70 wt% nitric acid into a one-liter three-necked jacketed glass reactor, while stirring at 300 rpm. Heat the mixture to 80 °C and hold for 26 hours. Cool the resulting clear solution to room temperature and neutralize to pH 7 with 8.83 parts of KOH. Place the solution in an aluminum tray in an oven at 45 °C for two days to obtain a film. Wash the dried film with water to remove salts, and 13 parts of dry PVOH are obtained.

[0464] Example 6: Charge 40 parts of PVB resin with 18.7% PVOH, 1000 parts of water, 0.16 parts of EDTA, and 14.2 parts of 70 wt% nitric acid into a one-liter three-necked jacketed glass reactor, while stirring at 300 rpm. Heat the mixture to 90 °C and hold for 26 hours. Cool the resulting clear solution to room temperature and neutralize to pH 7 with 8.83 parts of KOH. Place the solution in an aluminum tray in an oven at 45 °C for two days to obtain a film. Wash the dried film with water to remove salts, and 25 parts of dry PVOH are obtained.

[0465] Example 7: Charge 2 parts of PVB resin with 10.5% PVOH, 1000 parts of water, 0.16 parts of EDTA, and 14.2 parts of 70 wt% nitric acid into a one-liter three-necked jacketed glass reactor. Stir at 300 rpm. Heat the mixture to 80 °C and hold for 40 hours. Cool the resulting clear solution to room temperature and neutralize to pH 7 with 8.83 parts of KOH. Place the solution in an aluminum tray in an oven at 45 °C for two days to obtain a film. Wash the dried film with water to remove salts, and 1.4 parts of dry PVOH are obtained.

[0466] Example 8: Charge 200 parts of post-consumer recycled PVB interlayer flakes (10 x 10 mm) and 1000 parts of water into a one-liter three-necked jacketed glass reactor. Adjust the pH of the mixture to between 1.5 and 2 with dilute sulfuric acid. Heat the mixture to 50 °C and hold for one hour with stirring. Filter and wash the resulting slurry, then air dry.

[0467] Example 9: Charge a mixture of 500 parts of alcohol (91% ethanol and 9% water) and 200 parts of DI water into a one-liter three-necked jacketed glass reactor. Add 100 parts of the PVB flakes from the above example to the stirred mixture and stir for 4 hours at room temperature (22 °C). Then filter the resulting mixture, and repeat the above process five more times using the filtered polymer flakes to obtain 65 parts of dry PVB resin flakes. Charge 45 parts of these PVB resin flakes and 1000 parts of alcohol (91% ethanol and 9% water) into a one-liter three-necked jacketed glass reactor. Heat the mixture to 70 °C with stirring at 200 rpm and hold for two hours. The dissolved mixture has 4.3% total solids and will be used in the next example.

[0468] Example 10: Charge 1000 parts of water, 0.16 part of EDTA, and 14.2 parts of 70 wt% nitric acid into a one-liter three-necked jacketed glass reactor while stirring at 300 rpm. Heat the mixture to 80 °C, and add 200 parts of the solution from Example 9 to the mixture over a two-hour period, and hold the mixture at 80 °C while stirring at 400 rpm for 22 hours until the suspended polymer dissolves. Filter the resulting solution hot under pressure through a 1-micron retention ErtelAlsop M-503p filter to obtain a clear solution, cool it to room temperature, and neutralize it to pH 7 with 8.83 parts of KOH. Place the solution in an aluminum tray in a 45 °C oven for two days to obtain a film. Wash the dried film with water to remove all salts and obtain 6 parts of dry PVOH.

[0469] Definitions

[0470] It should be understood that the following is not intended to be an exhaustive list of the defined terms. Other definitions may be provided in the foregoing description, for example, in the context of the use of the defined terms.

[0471] As used herein, the terms "a", "an", and "the" mean one or more.

[0472] 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 can be used alone or any combination of two or more of the listed items can be used. For example, if a composition is described as containing components A, B, and / or C, then the composition can contain only A; only B; only C; 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.

[0473] As used herein, the phrase "at least a portion" includes at least a portion and up to and including the entire amount or time period.

[0474] As used herein, the term "chemical recycling" refers to a PVB recycling method that includes the step of chemically converting waste PVB into lower molecular weight polymers, oligomers, monomers, and / or non-polymeric molecules (e.g., carbon monoxide, C2-C4 aldehydes, ethylene, and propylene) that are themselves useful and / or can be used as raw materials for another chemical production process.

[0475] As used herein, the terms "comprising," "comprises," and "comprise" are open transitional terms used to transition from the subject recited before the term to one or more elements recited after the term, where the one or more elements listed after the transitional term are not necessarily the only elements that make up the subject.

[0476] As used herein, the term "directly derived" means having at least one physical component derived from recycled PVB.

[0477] As used herein, the terms "having," "has," and "have" have the same open meaning as "comprising," "comprises," and "comprise" provided above.

[0478] As used herein, the terms "including," "include," and "included" have the same open meaning as "comprising," "comprises," and "comprise" provided above.

[0479] 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 board.

[0480] As used herein, the term "separation" refers to the property of one or more objects being on their own or by themselves and separated from other materials (whether dynamically or statically).

[0481] As used herein, the term "pre-treatment" refers to preparing a PVB composition for chemical recycling using one or more of the following steps: (i) pulverizing, (ii) granulating, (iii) washing, (iv) drying, and / or (v) separating.

[0482] As used herein, the terms "recycled component" and "regenerated" refer to a composition that is or contains a composition directly and / or indirectly derived from a recycled / waste PVB composition.

[0483] As used herein, the terms "monolithic" interlayer and "integral" interlayer refer to an interlayer formed from a single resin sheet, while the terms "multiple layer" and "multi-layer" interlayers refer to an interlayer having two or more resin sheets that are co-extruded, laminated, or otherwise connected to each other.

[0484] Numerical ranges

[0485] This specification uses numerical ranges to quantify certain parameters related to the present invention. It should be understood that when numerical ranges are provided, these ranges should be interpreted as providing literal support for claims that recite only the lower limit of the range and for claims that recite only the upper limit of the range. For example, the disclosed numerical range of 10 to 100 provides literal support for claims that recite "greater than 10" (without an upper limit) and for claims that recite "less than 100" (without a lower limit).

[0486] In addition, it should be understood that a list of numerical values following a descriptor, such as "at least" and "not exceeding", provides literal support for ranges based on all of the numerical values following that descriptor. For example, a statement specifying "at least 2, 5, or 10 and / or not exceeding 100, 50, or 25" will provide literal support for ranges of "at least 25", "not exceeding 50", and "at least 10 and not exceeding 25".

[0487] The claims are not limited to the disclosed embodiments

[0488] The preferred forms of the present invention described above are for illustrative purposes only and should not be construed in a limiting sense to interpret the scope of the present invention. Those skilled in the art can easily modify the above exemplary embodiments without departing from the spirit of the present invention.

[0489] The inventors hereby state that they intend to determine and evaluate the reasonable and fair scope of the present invention under the doctrine of equivalents as it relates to any 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. A method for recycling polyvinyl butyral (PVB), the method comprises: Hydrolyzing or partially hydrolyzing a PVB raw material to produce a solution comprising regenerated polyvinyl alcohol (PVOH) derived from the PVB raw material.

2. The method according to any one of claim 1, wherein the hydrolysis or partial hydrolysis occurs in the absence of a catalyst.

3. The method according to claim 2, wherein the hydrolysis or partial hydrolysis occurs in the absence of a catalyst and at a temperature in the range between about 150 °C and about 250 °C.

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

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

6. The method according to claim 4, wherein the hydrolysis or partial hydrolysis occurs in the presence of one or more of an acid catalyst or a cocatalyst that forms an unstable hydrolysable molecule.

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

8. The method according to any one of claims 1-7, wherein the PVB raw material is hydrolyzed to PVOH with a conversion rate of at least 90%.

9. The method according to any one of claims 1-7, wherein the PVB raw material is partially hydrolyzed to a conversion rate 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. The method according to any one of claims 1-7 and 9, wherein the partial hydrolysis of the PVB raw material produces a slurry comprising water-insoluble PVB in the range of between 25% and 75%, between 30% and 70%, between 35% and 65%, or between 40% and 60% by weight.

11. The method according to any one of claims 1-7 and 9, wherein the partial hydrolysis of the PVB raw material produces a slurry comprising about 75% to about 99% water or 80% to 98% water by weight.

12. The method according to any one of claims 1-11, the method further comprises cooling the regenerated PVOH before the reaction step.

13. The method according to any one of claims 1-12, the method further comprises centrifuging the solution before the filtration step to remove one or more insoluble components from the solution.

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

15. The method according to any one of claims 1-14, wherein the PVB raw material has a residual PVOH content of 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 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90%, and / or not exceeding 100%, not exceeding 90%, not exceeding 80%, not exceeding 70%, not exceeding 60%, not exceeding 50%, not exceeding 40%, not exceeding 35%, not exceeding 32%, not exceeding 30%, not exceeding 25%, not exceeding 22%, not exceeding 20%, not exceeding 19%, not exceeding 18%, not exceeding 17%, not exceeding 16%, not exceeding 15%, not exceeding 14%, not exceeding 13%, not exceeding 12%, not exceeding 11%, not exceeding 10%, not exceeding 9% or not exceeding 8%.

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

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

18. The method according to any one of claims 1-17, wherein based on the total weight of the PVB raw material, the PVB raw material comprises at least 1 phr, at least 5 phr, at least 10 phr, at least 15 phr, at least 20 phr, at least 25 phr, at least 30 phr, at least 35 phr, at least 40 phr, at least 45 phr, at least 50 phr, at least 55 phr, at least 60 phr, at least 65 phr, at least 70 phr, at least 75 phr, at least 80 phr, at least 85 phr or at least 90 phr, and / or not exceeding 100 phr, not exceeding 90 phr, not exceeding 85 phr, not exceeding 80 phr, not exceeding 75 phr, not exceeding 70 phr, not exceeding 65 phr, not exceeding 60 phr, not exceeding 55 phr, not exceeding 50 phr, not exceeding 45 phr, not exceeding 40 phr, not exceeding 35 phr, not exceeding 30 phr, not exceeding 25 phr, not exceeding 20 phr, not exceeding 15 phr or not exceeding 10 phr of a plasticizer.

19. The method according to claims 1-18, the method further comprising extracting the plasticizer from the PVB raw material.

20. The method according to any one of claims 1-19, the method further comprising reducing the size of the 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, prior to the hydrolysis step.

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

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

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

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

Images