Use of styrene polymer obtained via depolymerization

Abstract

To provide a styrenic polymer derived from depolymerization capable using in places where a conventional high molecular weight polystyrenic plastic cannot be used without modifying.SOLUTION: A latex and solution containing UV-active monomers are made using styrenic polymers created through the depolymerization of polystyrene raw materials. In some embodiments, the polystyrene raw materials include recycled polystyrene. In some embodiments, the styrenic polymer includes olefins. In some embodiments, the latex and solution containing UV-active monomers are used in ink formulations. In some embodiments, the latex and solution containing UV-active monomers can replace styrenated acrylics in flexo and / or gravure ink formulations. Other applications may include coatings, paints, and adhesives. Additional applications of the latex may include immunoassays.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is related to and claims the benefit of priority to U.S. Provisional Application No. 62 / 678,780, filed May 31, 2018, entitled "Uses of Styrenic Polymers Derived Through Depolymerized Polystyrene." The '780 provisional application is incorporated herein by reference in its entirety. [Background technology]

[0002] The present invention relates to the use of styrenic polymers synthesized via depolymerization of polystyrene to produce water-based and solvent-based formulations, including but not limited to latexes and solutions with UV-active monomers. The UV-active monomers used include but are not limited to acrylate-based systems, such as trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, poly(ethylene glycol) diacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated 1,6-hexanediol diacrylate, ethoxylated 1,6-hexanediol diacrylate. Additionally, styrenic polymers synthesized via depolymerization of polystyrene are also readily soluble in organic solvents. Examples include but are not limited to chloroform, tetrahydrofuran, toluene, xylene, cymene, or terpinene. The resulting formulations can be used in a variety of applications, including but not limited to inks, paints, coatings, and adhesive formulations. In some embodiments, the resulting formulations act to offset / replace polymers within these application formulations, such as styrenated acrylic. In some applications, latexes utilizing polymers synthesized via depolymerization of polystyrene can be used directly as an offset to currently used styrene-based latexes, hi some embodiments, polystyrene-based latexes can be used in immunoassay tests.

[0003] Polystyrene is one of the fastest growing solid wastes. Moreover, polystyrene is non-biodegradable and accumulates in nature. Most polystyrene waste is buried or incinerated; the former leads to material loss and land waste, the latter leads to greenhouse gas emissions. Currently, only a small proportion of polystyrene waste is recycled as a secondary polymer (less than 5% in North America and Europe).

[0004] Conventional polystyrene plastic is synthesized via the polymerization of styrene, which in turn is synthesized by the ethylation of benzene (often obtained from crude oil) to produce ethylbenzene, which is then dehydrogenated.

[0005] Traditionally, polystyrene latexes are produced by emulsion polymerization, a technique in which polystyrene chains are produced from monomers via emulsion. In a typical embodiment, these latices consist of polystyrene that has been modified to introduce polarity (e.g., by the addition of carboxylic acid or amine moieties).

[0006] Traditionally, UV-active monomers used in formulations are acrylic-based, examples include, but are not limited to, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, poly(ethylene glycol) diacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated 1,6-hexanediol diacrylate, and ethoxylated 1,6-hexanediol diacrylate.

[0007] Styrenic polymers obtained from depolymerized polystyrene have different properties than the starting plastic material, whereas conventional polystyrene plastics are synthesized via polymerization of styrene. For example, medium molecular weight styrenic polymers made via depolymerization of polystyrene often contain specific structural or chemical characteristics, including but not limited to olefin content or longer aliphatic segments near the chain end positions. Additionally, styrenic polymers made via depolymerization of polystyrene often have low molecular weights. Summary of the Invention

[0008] In some embodiments, the latex / solution may be comprised of a styrenic polymer made via depolymerization of a polystyrene feedstock, hi some embodiments, the polystyrene feedstock comprises recycled polystyrene and / or virgin polystyrene.

[0009] In some embodiments, the particle size of the latex / solution is greater than 1 nanometer, hi certain embodiments, the particle size of the latex / solution is between 150 and 220 nanometers, inclusive.

[0010] In some embodiments, the styrenic polymer is solubilized in a UV-active monomer to produce a stable formulation.

[0011] In some embodiments, the styrenic polymer comprises at least one olefin on the chain backbone, typically near the end, hi certain embodiments, the olefin content is less than 1% of the total weight of the styrenic polymer.

[0012] In some embodiments, the styrenic polymer has a molecular weight between 20,000 and 200,000 amu.

[0013] In certain embodiments, the styrenic polymer has a melt flow index of from 10 g / 10 min to 200 g / 10 min, inclusive.

[0014] In some embodiments, the ink can include a latex, particularly including a styrenic polymer created via depolymerization of a polystyrene feedstock, a solvent, a pigment, and additives, hi some embodiments, the pigment is selected from the group consisting of organic pigments or mineral pigments.

[0015] In some embodiments, the ink may include styrenic polymers, particularly those made via depolymerization of polystyrene raw materials, UV active monomers, oligomers, pigments, photoinitiators, and / or additives, hi some embodiments, the pigment is selected from the group consisting of organic pigments or mineral pigments.

[0016] In some embodiments, the coatings, adhesives, and / or immunoassay tests can include latexes / solutions that include styrenic polymers, particularly those made via depolymerization of polystyrene raw materials.

[0017] In some embodiments, the paints, coatings, and / or adhesives may include styrenic polymers, particularly those made via the depolymerization of polystyrene feedstocks.

[0018] In some embodiments, the styrenic polymer comprises at least one olefin, hi some embodiments, the olefin is less than 1% of the total weight of the styrenic polymer. [Brief description of the drawings]

[0019] [Figure 1] 1 is a flow chart illustrating a process for treating polystyrene material to produce a styrenic polymer.

[0020] [Diagram 2] FIG. 1 is a schematic diagram of a phase inversion emulsification procedure.

[0021] [Diagram 3] FIG. 1 is a schematic diagram of a process for making a styrenic polymer / UV active monomer blend.

[0022] [Figure 4] 1 is a flow chart illustrating a process for making an ink using a styrene-based polymer.

[0023] [Diagram 5] 1 is a flow chart illustrating a process for making an oligomer / monomer blend using a styrenic polymer.

[0024] [Figure 6]1 is a series of overlaid differential scanning calorimetry (DSC) thermograms of various styrenic polymers produced via depolymerization of polystyrene.

[0025] [Figure 7] 1 is a nuclear magnetic resonance (NMR) spectrum of a styrene-based polymer produced via depolymerization.

[0026] [Figure 8] FIG. 8 is an expanded version of section A of FIG. 7 showing peaks corresponding to the presence of olefins.

[0027] [Figure 9] FIG. 1 is a graph showing the rheology of various inks, including those made with styrenic polymers created via the depolymerization of polystyrene.

[0028] [Figure 10] 1 is a photograph of a styrene-based polymer latex.

[0029] [Figure 11] Photograph of a styrenic polymer / UV-active monomer blend. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS Styrenic polymers derived from depolymerized polystyrene can be used where traditional high molecular weight polystyrene plastics cannot be used without modification, including, but not limited to, inks, paints, coatings, adhesive formulations, and / or immunoassay tests.

[0031] Styrenic polymers derived from depolymerized polystyrene can also be used as replacements for traditionally used materials derived from crude oil. One application of styrenic polymers created through the depolymerization of polystyrene is to replace styrenic acrylics in water-based inks such as flexographic and gravure ink formulations. Traditionally styrenic acrylics are used in conjunction with solvents, pigments, and additives in water-based ink formulations. One of the problems with using polystyrene plastics in water-based inks is that they are insoluble due to their high molecular weight and lack of polarity. This challenge is overcome through the controlled depolymerization of polystyrene plastics to produce low molecular weight, highly polar styrenic polymers. The ability to tailor the properties of styrenic polymers derived from depolymerized polystyrene plastics allows styrenic polymer products to be specifically engineered for use in latex formulations. The use of styrenic polymers derived from waste polystyrene plastics helps to reduce greenhouse gases, landfill waste, and the need for the production of new styrenic products derived from fossil or virgin polystyrene.

[0032] A method is disclosed for producing latex formulations using styrenic polymers. These latices can be used in a variety of applications, including inks.

[0033] In some embodiments, the polystyrene material is first converted into a styrenic polymer. A process for achieving this is described in International Application PCT / CA2017 / 051166 (incorporated herein by reference). In some embodiments, the polystyrene material is recycled. Converting the polystyrene material into a styrenic polymer can include: selecting a solid polystyrene material; heating the solid polystyrene material in an extruder to create a molten polystyrene material; filtering the molten polystyrene material; passing the molten polystyrene material through a chemical depolymerization process in a reactor to create a styrenic polymer; cooling the styrenic polymer; and / or purifying the styrenic polymer.

[0034] In at least some embodiments, the material does not need to be purified. In at least some embodiments, the additives / residues do not destroy the latex formulation. In at least some embodiments, the styrenic polymer can be dispersed in water to create various latexes and / or emulsions. In at least some embodiments, this is accomplished via traditional emulsification techniques, such as phase inversion emulsification, in which the styrenic polymer is dissolved in a complementary solvent and transferred to an aqueous dispersion (latex), followed by stripping of the original compatible solvent.

[0035] Figure 2 shows one embodiment of phase inversion emulsification. In steps 202 and 204, water is gradually added to a hydrophobic polymer dissolved in an organic solvent. In step 206, saturation inversion occurs (water droplets in oil become oil droplets in water). In step 208, the organic solvent is removed by distillation to obtain a stable latex emulsion.

[0036] Other processes can be used to form the latex, including, but not limited to: attrition of the polymer to water containing at least one surfactant; homogenization of the polymer in at least one solvent having water and at least one emulsifier; mixing of the molten polymer with at least one emulsifier and hot water under high pressure, high temperature, and / or high shear forces; and ultrasonic techniques.

[0037] The latexes produced by the above methods can be used in a variety of products, including, but not limited to, ink formulations. In some embodiments, these styrenic polymer latexes can replace styrenated acrylics in flexographic and / or gravure ink formulations. Other uses for styrenic polymer latexes include, but are not limited to, coatings, paints, adhesives, and immunoassays.

[0038] In at least some embodiments, the styrenic polymer is soluble in organic media and / or aqueous formulations.

[0039] Another application of styrenic polymers created via the depolymerization of polystyrene is to replace traditional oligomeric components in solvent-based ink formulations. Traditionally, oligomers are used in conjunction with monomers, pigments, photoinitiators, and additives in water-based ink formulations.

[0040] In at least some embodiments, the styrenic polymers made via the depolymerization of polystyrene do not need to be purified. In at least some embodiments, additives / residues do not interfere with the solubilization process.

[0041] Other applications of the styrenic polymer / UV active monomer formulations include, but are not limited to, coatings, paints, and adhesives.

[0042] 3 shows one embodiment of solubilizing a styrenic polymer in a UV-active monomer. The styrenic polymer is slowly added to the UV-active monomer at the desired temperature in step 302. The mixture is then vigorously stirred to induce solubilization in step 304.

[0043] In some embodiments, the styrenic polymer contains active sites (such as olefin moieties). These active sites are often characteristic of materials produced by depolymerization processes. In some embodiments, the depolymerization process incorporates additional olefin content into the polymer backbone. The backbone or terminal olefins are identifiable features not present in styrenic polymers obtained by polymerization methods. Figures 7 and 8 show nuclear magnetic resonance (NMR) spectra of styrenic polymer materials, supporting the presence of styrene species. Backbone or terminal olefins containing double bonded carbon atoms are inherently more polar compared to polymers with saturated backbones. This makes olefin-containing polymers more compatible in aqueous latex formation than conventional polystyrene. The olefin content also aids in improved solubilization in various UV-active monomers.

[0044] In some embodiments, the styrenic polymer can be further modified to add additional active sites such as carboxylic acids, maleic acid, maleic anhydride, and amines. The active sites can serve the purpose of functionalization. In some embodiments, various monomers and / or copolymers, including but not limited to acids, alcohols, acetates, amines, and alkenes (e.g., hexene), can be grafted onto the depolymerized product to improve compatibility and / or add functional groups.

[0045] In some embodiments, various monomers and / or copolymers are grafted via the olefin fingerprint to improve compatibility and / or add functional groups. Grafting can occur in the reactor, in a post-cooling stream, and / or in a separate vessel, among other locations.

[0046] In some embodiments, various monomers and / or copolymers are grafted through aromatic functionality to improve compatibility and / or add functionality. Grafting can occur in the reactor, in a post-cooling stream, and / or in a separate vessel, among other locations.

[0047] In some embodiments, the polystyrene material is dissolved in a specific solvent prior to depolymerization to adjust the viscosity of the polymer at various temperatures. In some embodiments, after dissolving the polystyrene using an organic solvent such as toluene, xylene, cymene, or terpinene, the polystyrene undergoes depolymerization in the reactor bed / vessel. In certain embodiments, the desired product can be isolated by separation or extraction, and the solvent can be recycled.

[0048] In at least some embodiments, no solvent is required.

[0049] In certain embodiments, the solid polystyrene material is recycled polystyrene. In some embodiments, the recycled polystyrene is pellets made from recycled expanded polystyrene and / or rigid polystyrene. Suitable waste polystyrene materials include, but are not limited to, mixed polystyrene waste, such as expanded and / or extruded polystyrene foam and / or rigid products. For example, styrofoam food containers and packaging products. Mixed polystyrene waste can include a variety of melt flows and molecular weights. In some embodiments, the waste polystyrene feedstock contains up to 25% of materials other than polystyrene materials, based on the total weight of the waste polystyrene feedstock. In some embodiments, virgin polystyrene can also be used.

[0050] In some embodiments, the polymeric feedstock is one or a combination of virgin polystyrene and / or one or a combination of post-industrial and / or post-consumer polystyrene.

[0051] In some embodiments, it is desirable to convert a polymeric feedstock to a lower molecular weight polymer with increased melt flow and olefin content. In some embodiments, this conversion is effected by heating the polystyrene feedstock to produce a molten polystyrene material and then contacting the molten polystyrene material with a catalytic material in a reaction zone brought to a temperature between 200° C. and 400° C., preferably between 275° C. and 375° C. In some embodiments, no catalyst is required.

[0052] The molecular weight, polydispersity, glass transition, melt flow, and olefin content produced via depolymerization depend on the residence time of the polystyrene material within the reaction zone.

[0053] In some embodiments, the depolymerization process utilizes a catalyst, such as [Fe-Cu-Mo-P] / Al2O3, zeolite, or alumina support systems, and / or thermal depolymerization. In some embodiments, the catalyst can be contained in a permeable vessel. In some embodiments, the depolymerization can occur through the action of a free radical initiator and / or exposure to radiation.

[0054] In some embodiments, purification of the styrenic polymer utilizes flash separation, distillation, vacuum stripping, absorption beds, clay polishing, and / or film evaporators.

[0055] FIG. 1 shows Process 1 for processing polystyrene materials. Process 1 can be carried out as a batch process or a continuous process. Process 1 parameters including, but not limited to, polystyrene grafted in the reaction and / or modification step, temperature, flow rate, and total number of preheat, reaction, or cooling segments can be modified to create styrenic polymers with various molecular weights from 20,000 to 200,000 amu, inclusive. In some more preferred embodiments, the styrenic polymers have various molecular weights from 50,000 to 150,000 amu, inclusive. In some even more preferred embodiments, the styrenic polymers have various molecular weights from 55,000 to 120,000 amu, inclusive.

[0056] In material selection stage 10, the polystyrene feedstock is screened / selected and / or prepared for processing. In some embodiments, the feedstock may contain up to 25% polyolefins, PET, EVA, EVOH, and lower levels of undesirable additives or polymers such as nylon, rubber, PVC, ash, fillers, pigments, stabilizers, grit, or other unknown particles.

[0057] In some embodiments, the polystyrene material has an average molecular weight of from 150,000 amu to 500,000 amu (inclusive). In some of these embodiments, the polystyrene material has an average molecular weight of from 200,000 amu to 250,000 amu (inclusive).

[0058] In some embodiments, the material selected in material selection step 10 comprises recycled polystyrene. In other or the same embodiments, the material selected in material selection step 10 comprises recycled polystyrene and / or virgin polystyrene.

[0059] In the solvent addition step 20, a solvent such as toluene, xylene, cymene, or terpinene is used to dissolve the polystyrene, which then undergoes depolymerization in the reactor bed / vessel. In certain embodiments, the desired products can be isolated by separation or extraction, and the solvent can be recycled.

[0060] In some embodiments, the material selected in material selection step 10 can be heated in an extruder in heating step 30 and subjected to a pre-filtration process 40. In some embodiments, the extruder is used to increase the temperature and / or pressure of the incoming polystyrene and to control the flow rate of the polystyrene. In some embodiments, the extruder is supplemented or completely replaced by a pump / heat exchanger combination.

[0061] In some embodiments, the molten polystyrene material is derived from a polystyrene feedstock that is heated to produce a molten polystyrene material. In some embodiments, the polystyrene feedstock comprises primary virgin granules of polystyrene. The virgin granules can comprise a variety of molecular weights and melt flows.

[0062] The pre-filtration process 40 can use both screen changers and filter beds along with other filtration techniques / equipment to remove and purify contaminants from the heated material. The resulting filtered material is then transferred to an optional pre-heating stage 50 where the filtered material is brought to a higher temperature before entering the reaction stage 60. The pre-heating stage 50 can use static and / or dynamic mixers, and heat exchangers such as internal fins and heat pipes, among other equipment and techniques.

[0063] The material in the reaction step 60 undergoes depolymerization. This depolymerization may be a purely thermal reaction and / or it may use a catalyst. Depending on the starting material and the desired styrenic polymer latex, depolymerization may be used to slightly or dramatically reduce the molecular weight of the starting material. In some embodiments, the catalyst used is a zeolite or alumina supported system, or a combination of the two. In some embodiments, the catalyst is [Fe-Cu-Mo-P] / Al2O3, which is prepared by binding an iron-copper complex to an aluminum or zeolite support and reacting it with an acid containing a metal or nonmetal to obtain a catalytic material. In some embodiments, the catalyst contains Al, Fe, Cu, and O, which is prepared by binding iron and copper complexes to an alumina and / or zeolite support. Other suitable catalytic materials include, but are not limited to, zeolites, mesoporous silica, H-mordenite, and alumina. This system can also be run without a catalyst to produce low molecular weight polymers by pyrolysis.

[0064] Reaction stage 60 can use a variety of techniques / equipment including, among others, fixed bed, horizontal and / or vertical reactors, and / or static mixers, In some embodiments, reaction stage 60 uses multiple reactors and / or reactors divided into multiple sections.

[0065] After reaction step 60, the depolymerized material enters an optional modification step 70. Modification step 70 includes grafting various monomers and / or copolymers, such as, but not limited to, acids, alcohols, acetates, and alkenes (e.g., hexene) onto the depolymerized product.

[0066] The cooling step 80 can use heat exchangers along with other techniques / equipment to bring the styrenic polymer latex down to a workable temperature prior to optional purification step 80. In some embodiments, the cooling step 80 is performed after washing / purifying the styrenic polymer by methods such as nitrogen stripping.

[0067] Optional purification step 90 includes purification and / or decontamination of the styrenic polymer. Techniques / equipment that can be used in purification step 90 include, but are not limited to, flash separation, absorption beds, clay grinding, distillation, vacuum distillation, and filtration to remove solvents, oils, color bodies, ash, inorganics, and coke. In some embodiments, thin film or wiped film evaporators are used to remove gases, oils, and / or greases, and / or low molecular weight functionalized polymers from the styrenic polymer latex. In some embodiments, the oils, gases, and low molecular weight functionalized polymers can then be combusted to help carry out the various steps of Process 1. In certain embodiments, the desired products can be isolated by separation or extraction, and the solvent can be recycled.

[0068] Process 1 ends with an end product step 100, where the original starting material selected in material selection step 10 has been converted into a styrenic polymer. In at least some embodiments, the styrenic polymer does not require additional processing and / or purification. In other embodiments, the styrenic polymer produced in the end product step requires additional modification.

[0069] In some embodiments, the styrenic polymer has an average molecular weight of 20,000 amu to 200,000 amu (inclusive), a melt flow (as measured by ASTM D1238) of 0 g / 10 min to 100 g / 10 min (inclusive), In some embodiments, the styrenic polymer has a glass transition temperature of 30 to 115° C. (inclusive).

[0070] In some embodiments, the styrenic polymer has an average molecular weight of from 40,000 to 100,000 (inclusive), a melt flow index (as measured by ASTM D1238) of from 10 g / 10 min to 200 g / 10 min (inclusive).

[0071] In some embodiments, the styrenic polymer contains between 0.1% and 5% olefin content on the chain backbone.

[0072] In some embodiments, the styrenic polymer contains more than 50 ppm zinc; more than 20 ppm titanium; and / or more than 20 ppm iron. In at least some embodiments, the presence of these metals confirms that the styrenic polymer is derived from either post-consumer polystyrene plastic or post-industrial polystyrene plastic. In some embodiments, these metals are well dispersed in the styrenic polymer, adding both polarity and reactivity. This dispersion makes the styrenic polymer more compatible with various organic and aqueous solvent formulations than traditional polystyrene. Furthermore, the added metal content allows the styrenic polymer to function as a coupling agent with other multi-polymer systems.

[0073] In some embodiments, the resulting latex has a particle size greater than 1 nanometer. In some embodiments, the resulting latex has a particle size greater than 1 micrometer. In some embodiments, the resulting latex has a particle size distribution between 50 and 300 nanometers, inclusive. In some preferred embodiments, the resulting latex has a particle size distribution between 100 and 250 nanometers, inclusive. In some more preferred embodiments, the resulting latex has a particle size distribution between 150 and 200 nanometers, inclusive.

[0074] In some embodiments, the depolymerization product material produced includes monomer (styrene), aromatic solvent, polyaromatic species, oil, and / or low molecular weight functionalized polymer (e.g., one with increased olefin content).

[0075] Styrenic Polymer Latex Ink Formulation Examples 4 illustrates a process 400 for using a styrenic polymer product created via a depolymerization process (such as that described in FIG. 1) to produce a final product such as, but not limited to, an ink. First, a styrenic polymer product is selected in select styrenic polymer 410. The styrenic polymer is then emulsified in emulsification stage 420 to create a latex. The resulting latex is then added in blending stage 430 to create a final product (e.g., an ink).

[0076] In an exemplary embodiment of the process, three styrenic polymers formed via depolymerization of polystyrene were identified for possible latex formulations (see Table 1): Polymer A (had low molecular weight); Polymer B (had medium molecular weight); and Polymer C (had high molecular weight). The molecular weights of the three polymers were varied, resulting in changes in glass transition temperatures. Figure 6 shows an overlay of differential scanning calorimetry thermograms of Polymers A-C showing the variation in glass transition temperatures. [Table 1]

[0077] Each polymer sample was successfully formed into a latex via phase inversion emulsification. In some of these embodiments, the latex is stable at room temperature for more than one year and has a solids loading range of 10% to 70%. In some preferred embodiments, the latex is stable at room temperature for more than one year and has a solids loading range of 20% to 60%. In some more preferred embodiments, the latex is stable at room temperature for more than two years and has a solids loading range of 25% to 45%.

[0078] Figure 10 is a photograph of a styrene-based polymer latex. The sample in the image is over 24 months old and has not experienced any phase change / separation / destabilization.

[0079] These latex formulations were then used to make various ink formulations (Polymer A Ink, Polymer B Ink, and Polymer C Ink) as shown in Table 2. [Table 2]

[0080] Polymer A, B, and C inks were subjected to several tests along with a control ink. In all tests the styrenic inks performed at least as well (abrasion resistance, coefficient of friction) if not better (blocking, reduced ink transfer during rub tests, overall image robustness) than the control ink. This indicates that styrenic polymers formed via depolymerization of waste polystyrene can act as a replacement for styrenated acrylics (derived from fossil fuel sources) in water-based ink formulations. The improved efficacy of the ink formulation is likely due to the hydrophobicity of the polymers and the molecular weight of the styrenic polymers used. Polymer C, the highest molecular weight polymer, gave significantly reduced ink transfer in rub tests and improved image robustness of the ink. Gradual improvement was seen as the molecular weight of the polymer increased (i.e., from Polymer A to Polymer C). [Table 3]

[0081] Additionally, the shear viscosity of the ink formulation polymers A, B, and C was significantly lower than that of the control ink. Figure 9 shows the rheology curves of the polymer inks A-C and the control ink. The rheological properties are somewhat dependent on the target application. However, a reduction in shear viscosity allows the ink to flow more effectively. This reduction is typically beneficial in flexographic and gravure ink applications. Additionally, styrene-based polymers can function as rheological additives / modifiers. As shown, different styrene-based polymers can be used and the rheology of the ink formulation can be modified and manipulated to meet the requirements / needs of the target formulation without adversely affecting the overall printing properties of the ink.

[0082] Examples of styrenic polymer / UV-active monomer blends 5 illustrates a process 500 for using a styrenic polymer product made via a depolymerization process (such as that described in FIG. 1) to create a final product such as, but not limited to, an ink. First, a styrenic polymer product is selected in styrenic polymer selection 510. The styrenic polymer is then solubilized in solubilization step 520 to create a stable oligomer / monomer blend. The resulting blend is then added to compounding step 530 to create the final product (e.g., ink).

[0083] In an exemplary embodiment of the process, styrenic polymers formed via depolymerization of polystyrene were identified for possible monomer solubilization formulations. See Table 4. [Table 4]

[0084] Styrenic polymers were successfully solubilized in UV-active monomers with styrenic polymer concentrations between 35% and 60% (inclusive), as shown in Table 5. In some preferred embodiments, the blends are stable at styrenic polymer concentrations between 45% and 60% (inclusive). In some more preferred embodiments, the blends are stable at styrenic polymer concentrations between 50 and 60% (inclusive).

[0085] Figure 11 is a photograph of a styrenic polymer / UV-active monomer blend. The sample in the image is over 6 months old and has not experienced any phase change / separation / destabilization. [Table 5]

[0086] In another series of tests, Polymer E was solubilized using 1,6-hexanediol and trimethylolpropane triacrylate. These formulations were then used to make various ink formulations as shown in Table 6. [Table 6]

[0087] In these examples, the UV-curable formulations with styrenic polymers performed similarly to the standard formulation in terms of application to the substrate, UV curing, and uniformity of the resulting film on black coated paper.

[0088] Although specific elements, embodiments, and applications of the invention have been shown and described, it will be understood that the invention is not limited to the foregoing teachings, since the invention can be modified without departing from the scope of the disclosure, particularly in light of the above teachings. For example, many of the embodiments demonstrate that different combinations of components are possible within the scope of the claimed invention, and these described embodiments are illustrative and show that other combinations of the same or similar components can be used to achieve substantially the same results in substantially the same manner. Moreover, all of the claims are incorporated by reference into the description of the preferred embodiments.

Claims

1. A latex containing a styrenic polymer created via the depolymerization of polystyrene feedstock.

2. Inks containing: a) a latex comprising a styrenic polymer prepared via depolymerization of a polystyrene feedstock; b) a solvent; c) pigments (organic or inorganic); and d) Additives.

3. Inks containing: a) styrenic polymers made via depolymerization of polystyrene feedstock; b) UV-active monomers; c) pigments (organic or inorganic); d) additives; and e) Photoinitiators.

4. Paints containing: a) A latex comprising a styrenic polymer made via the depolymerization of a polystyrene feedstock.

5. Paints containing: a) Styrenic polymers made via the depolymerization of polystyrene feedstock.

6. Adhesives including: a) A latex comprising a styrenic polymer made via the depolymerization of a polystyrene feedstock.

7. Adhesives including: a) Styrenic polymers made via the depolymerization of polystyrene feedstock.

8. Coatings including: a) A latex comprising a styrenic polymer made via the depolymerization of a polystyrene feedstock.

9. Coatings including: a) Styrenic polymers made via the depolymerization of polystyrene feedstock.

10. Immunoassay tests, including: a) A latex comprising a styrenic polymer made via the depolymerization of a polystyrene feedstock.

11. 11. The article of any one of claims 1 to 10, wherein the polystyrene feedstock comprises recycled polystyrene.

12. The article of any one of claims 1 to 10, wherein the polystyrene source comprises virgin polystyrene.

13. 11. The article of any one of claims 1, 2, 4, 6, 8, or 10, wherein the particle size of the latex is greater than 1 nm.

14. 11. The article of any one of claims 1, 2, 4, 6, 8, or 10, wherein the latex has a particle size of 150 to 220 nanometers, inclusive.

15. A solution containing a styrenic polymer produced by depolymerizing polystyrene feedstock and a UV-active monomer.

16. 16. The article of any one of claims 1 or 15, wherein the styrenic polymer comprises at least one olefin.

17. 17. The article of claim 16, wherein the at least one olefin is less than 1% of the total weight of the styrenic polymer.

18. 16. The article of any one of claims 1 or 15, wherein the styrenic polymer has a molecular weight between 20,000 and 200,000 amu.

19. 16. The article of any one of claims 1 or 15, wherein the styrenic polymer has a melt flow index of from 10 g / 10 min to 200 g / 10 min, inclusive.

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