PVC composition for gel molding applications

Abstract

A method of making a polyvinyl chloride-based powder composition includes blending an emulsion of a polyvinyl chloride resin and a flexible acrylic resin to form a polyvinyl chloride resin / flexible acrylic resin blend. The polyvinyl chloride / flexible acrylic resin blend is separated to form the polyvinyl chloride-based powder composition. A polyvinyl chloride-based powder composition, a polyvinyl chloride formulation, an article formed from the polyvinyl chloride-based powder composition, and a method for forming the article are also disclosed.

Description

Technical Field

[0001] The present invention relates to a powder composition based on polyvinyl chloride (PVC), a method for preparing a powder composition based on polyvinyl chloride and an article prepared therefrom. Background Art

[0002] Polyvinyl chloride (PVC) is a widely used material in various market sectors, such as automotive; building and construction; medical and consumer healthcare; and residential and commercial construction. PVC is also widely used in soft-touch applications in automotive interiors, such as artificial leather or skins for structural elements (including dashboards, door panels, etc.). Slush molding of interior soft skins is a method that produces optimal surface replication in multiple particles across a part. Slush molding is the preferred method for making interior soft skins for dashboards and door panels and other interior decorative parts. For example, parts require complex shapes, particle mixtures, geometric particles, deep contour lettering and logos. Using slush molding, a surface with excellent tactile feel and adjustable gloss is achieved. In order to improve the flexibility of PVC materials at low temperatures (e.g., -30°C ductility), a plasticizer is used at a concentration of approximately (~) 50 parts per hundred (phr) to provide sub-zero temperature ductility.

[0003] To date, plasticizers have been widely used in PVC materials to provide ductility. However, plasticizers tend to migrate over time; therefore, plasticizers may be detrimental to the integrity of PVC materials. For example, over time, plasticizer migration can adversely cause "fogging" and brittleness to PVC materials. Therefore, over time, the performance of the PVC skin deteriorates. And, despite the use of "super" stabilizers in PVC materials, the use of known plasticizers still has the problem of plasticizer migration. In addition, some plasticizers (including phthalates) cause additional problems related to toxicity. Therefore, it is desirable to reduce or minimize the amount of plasticizers in PVC compositions.

[0004] In the automotive industry, deployment of airbags in automobiles at low (sub-zero) temperatures has become problematic as the PVC skin degrades over time. The brittle PVC skin tends to crack and shatter at low temperatures as the airbag deploys. During deployment of a low temperature airbag, shattering of the airbag door area can create airborne debris that can cause personal injury to occupants in the automobile. Providing an airbag with a skin made of PVC material that will not shatter during deployment is a critical requirement for installing PVC airbags in both new vehicles as well as "end of life" vehicles.

[0005] Automakers often use heat aging tests to predict and understand the performance of aged instrument panels. For example, it has been found that plasticized PVC will sacrifice more than 35 percent (%) of its original physical properties when exposed to high temperatures above 110°C for 500 hours or more. When plasticized PVC is exposed to such high temperatures, the plasticized PVC loses its physical properties and the plasticized PVC becomes brittle. The accelerated loss of plasticizers leads to embrittlement of articles made of plasticized PVC. Therefore, an airbag with a skin made of plasticized PVC may cause the PVC material to break when it becomes brittle and unfolds, especially when an airbag made of plasticized PVC material is unfolded at low temperatures (e.g., at a temperature of -30°C). Therefore, in the automotive industry, there is a need for a technology that improves the heat aging performance of plasticized PVC and is able to maintain the low temperature ductility of plasticized PVC throughout the service life of a vehicle employing components made of plasticized PVC.

[0006] U.S. Patent Application Publication No. 2021 / 0017372 discloses a PVC-based composition comprising a flexible acrylic resin (FAR). PVC and FAR are blended with a plasticizer to form a mixture for making articles therefrom.

[0007] Conventional slush molding compositions usually comprise suspension PVC (S-PVC) resin, emulsion PVC (E-PVC) resin, plasticizer and other components such as stabilizer, UV stabilizer, pigment etc. used as flow aid.S-PVC and plasticizer are the main components of slush molding compositions.Due to the problems of the above-mentioned plasticizer, it is desirable to reduce or minimize the amount of the plasticizer used in slush molding applications.

[0008] It has been found that blends of PVC (including S-PVC and E-PVC) and FAR powders cannot be processed under slush molding conditions that rely solely on heating and provide zero shear. It is therefore desirable to develop a powder PVC composition that can be slush molded and still maintain the low temperature ductility of plasticized PVC. Summary of the invention

[0009] One aspect of the present invention relates to a method for preparing a polyvinyl chloride-based powder composition, the method comprising:

[0010] a) blending an emulsion of a polyvinyl chloride resin and an emulsion of a flexible acrylic resin to form a polyvinyl chloride resin / flexible acrylic resin blend; and

[0011] b) isolating the polyvinyl chloride resin / flexible acrylic resin blend to form the polyvinyl chloride-based powder composition.

[0012] Another aspect of the present invention relates to a polyvinyl chloride-based powder composition prepared according to the other aspects of the present invention.

[0013] Yet another aspect of the present invention relates to a composition comprising polyvinyl chloride powder and a polyvinyl chloride-based powder composition prepared according to other aspects of the present invention.

[0014] Still another aspect of the present invention relates to an article made from the polyvinyl chloride-based powder composition prepared according to other aspects of the present invention.

[0015] Another aspect of the present invention relates to a method for preparing an article from a polyvinyl chloride-based powder composition, the method comprising the following steps:

[0016] 1) preparing a polyvinyl chloride based powder composition by:

[0017] a) blending an emulsion of a polyvinyl chloride resin and an emulsion of a flexible acrylic resin to form a polyvinyl chloride resin / flexible acrylic resin blend; and

[0018] b) separating the polyvinyl chloride resin / flexible acrylic resin blend to form the polyvinyl chloride-based powder composition; and

[0019] II) forming an article from the polyvinyl chloride-based powder composition of step I). BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a core-shell polymer material showing the various layers of the core-shell material of the present invention.

[0021] Figure 2 Shown are AFM tapping mode images of formulations containing plasticized PVC without FAR.

[0022] Figure 3 Shown are AFM tapping mode images of formulations containing plasticized PVC and FAR according to embodiments of the present invention.

[0023] Figure 4 Shown are AFM tapping mode images of formulations containing plasticized PVC and FAR according to embodiments of the present invention.

[0024] Figure 5 Shown are AFM tapping mode images of formulations containing plasticized PVC and FAR according to embodiments of the present invention. DETAILED DESCRIPTION

[0025] definition

[0026] As used herein with respect to a material, "ductility" or "ductile" means that the material is flexible and that a sheet of the material can perform (at a given temperature) without breaking. The cold flex test in Ford specification WSS-M4D985-A3 defines a material as flexible in which a sheet sample (50×150 mm) can be bent 180 degrees on a 20 mm diameter mandrel without breaking. Similarly, a dart impact test as defined in ISO 6603 or ASTM D376 defines ductility as the ability of a dart to penetrate a film sample at a certain speed (e.g., 6.7 meters per second (m / s)) without inducing any cracking or breaking.

[0027] As used herein with respect to a material, "low temperature impact performance" means the ability of a material to withstand high forces or impacts applied to the material for a short period of time. Herein, low temperature impact performance is the ability of a material to be ductile at sub-zero temperatures (e.g., temperatures between 0°C and -40°C).

[0028] "Heat aging" as used herein with respect to a material means the ability of a material to retain properties after conditioning at elevated temperatures (above ambient temperature) for extended periods of time (e.g., 1,000 hours at 120°C). Ford specification WSS-M4D985-A3 defines acceptable heat aging of a material as a loss in tensile strength of less than (<) 25% of the material's original value, and a loss in elongation at break of less than 50% of the material's original value.

[0029] "Impact resistance" as used herein with respect to a material means the ability of a material to withstand high forces or impacts applied to the material for a short period of time. Good impact resistance is the ability of a material to absorb energy and deform plastically without breaking (also known as "toughness").

[0030] As used herein, "tailored polymer melt rheology" with respect to a resin product means that the resin product can be processed into film / sheet or injection molded into articles using conventional plastic melt processing equipment including, for example, film extrusion / calendering, injection molding, and thermoforming.

[0031] "Compatibility" as used herein with respect to polymers refers to the ability of two polymers to mix at a uniform level such that the resulting polymer blend produces the desired properties.

[0032] "Miscibility" as used herein with respect to polymers means the ability of two polymers to form a very homogeneous polymer blend at the molecular level.

[0033] As used herein with respect to plasticizers, "migration" means the removal of plasticizers from a component (e.g., a sheet, skin, or molded component) and the loss of plasticizers to the environment or into a composite material adjacent to the component (e.g., a PU foam). Migration is a function of temperature and time, and increases with higher temperatures (e.g., above ambient temperature) and longer times.

[0034] "Tensile strength" as used herein with respect to a material means the maximum stress that a material can withstand when stretched or pulled (eg, according to the film tensile testing procedure described in ASTM D882).

[0035] In one aspect of the present invention, the PVC-based composition of the present invention is prepared by a process comprising blending an emulsion of a PVC resin with an emulsion of a FAR resin to form a PVC / FAR blend. The PVC / FAR blend is then separated to form a PVC-based powder composition.

[0036] Emulsion PVC (E-PVC) resins and suspension PVC (S-PVC) resins differ primarily in particle size. E-PVC resins typically have a smaller particle size than S-PVC resins. In conventional rotational molding applications (including slush molding), E-PVC resins are primarily used as flow aids. PVC resins for powders may include, for example, emulsion grades of PVC, designated by those having "K" values ​​of K56 to K72 in the industry. As known to those skilled in the art, the "K" value is a measure of the molecular weight of the PVC resin based on a measurement of the viscosity of a PVC solution as described in ISO 1628-2 (1998). A higher K value indicates a higher PVC molecular weight. PVC materials of K56 to K72 PVC grades are typically used, for example, to make packaging applications; and film and sheet products for building and construction applications.

[0037] Typically, the amount of the PVC resin component in the PVC-based powder composition may be, for example, 20 to 90 wt %; for example, 30 to 90 wt %, 40 to 80 wt % or 55 to 60 wt %, based on the total weight of all components in the PVC-based powder composition.

[0038] The FAR resin may be a core-shell polymer resin product comprising at least one or more of the following layers: (i) a crosslinked core; (ii) an intermediate region layer; and (iii) an outermost layer. Figure 1 , shows a FAR core-shell polymer resin, generally indicated by the numeral 10, comprising a crosslinked core 11, an intermediate layer 12 and an outer layer or shell 13. Figure 1 As indicated by line X in , the overall size of the core-shell polymer resin product 10 may be 90 nanometers (nm) to 120 nm, 140 nm to 170 nm, or 230 nm to 300 nm.

[0039] For example, the FAR resin may include a copolymer of methyl methacrylate (MMA) and butyl acrylate (BA), wherein the cross-linked BA is the core 11; and the MMA-rich composition is the outermost layer or shell 13. In other examples, suitable FAR resin compounds may include, for example, FAR resin product grades available from The Dow Chemical Company, such as products designated 21308-XP, 21309-XP and 21520-XP, 21501-XP; and mixtures thereof.

[0040] Typically, the concentration of the FAR resin for use in PVC-based compositions can generally range from 1 wt % to 60 wt %; 5 wt % to 60 wt %; 20 wt % to 45 wt %; or 15 wt % to 35 wt %, based on the total weight of all components in the composition.

[0041] Reference again Figure 1 , showing a crosslinked core 11 that may include one or more materials. In one embodiment, the crosslinked core 11 may include greater than (>) 95 wt % of units derived from, for example, one or more monomers selected from (meth) alkyl acrylate monomers, and 0.1 wt % to 5 wt % of units derived from a crosslinking monomer, a graft-linking monomer, or a combination thereof. The crosslinked core 11 may exhibit a glass transition temperature (T ) of -85°C to -10°C. g In one embodiment, the core 11 may be, for example, a cross-linked rubber. The cross-linked rubber advantageously provides impact resistance to articles made from the PVC-based powder composition.

[0042] The diameter of the core layer 11 may be in the range of, for example, 90 nm to 100 nm, 120 nm to 130 nm, or 200 nm to 210 nm. However, the diameter of the core layer 11 may have other diameters depending on the desired purpose.

[0043] The intermediate region 12 may include one or more intermediate layers. For example, each of the intermediate layers used may contain 88.5 wt % to 100 wt % of units derived from one or more monomers selected from (meth) alkyl acrylate monomers, and 0 wt % to 5 wt % of units derived from (i) crosslinking monomers, (ii) grafting monomers, or (iii) a combination of two or more thereof. Optionally, one or more intermediate layers may contain 0 wt % to 2.0 wt % of units derived from one or more chain transfer agents, so that a composition gradient is provided between the intermediate layers. The composition gradient of one or more intermediate layers may be at a lower T g With higher T g between transitions, where the lower T gCan be at least -30°C, and higher T g It may be up to 70° C. The intermediate layer may advantageously provide tailored polymer melt rheology for melt processing.

[0044] The outermost layer or shell 13 may include one or more materials. For example, the outermost layer or shell 13 may include 98.5 wt % to 100 wt % of units derived from one or more monomers selected from alkyl (meth)acrylates, styrene monomers, and combinations of two or more thereof. Optionally, the outermost layer 13 may include, for example, 0 wt % to 1.5 wt % of units derived from one or more chain transfer agents; and the outermost layer 13 may have, for example, a T of 40° C. to 110° C. g The optional functional groups incorporated into the outer layer 13 advantageously provide a compatibilizing effect between the core-shell polymer resin product and other polymeric substrates.

[0045] Optionally, the step of blending the emulsion of PVC resin and the emulsion of FAR resin may also include blending one or more heat stabilizers, one or more UV stabilizers and / or one or more antioxidants to form a PVC / FAR blend. Alternatively, one or more of these components may be blended with additional PVC resin when forming a PVC formulation comprising a PVC-based powder composition.

[0046] In a preferred embodiment, the method for preparing a PVC-based powder composition comprises blending an emulsion of a PVC resin, an emulsion of a FAR resin, and optionally a heat stabilizer to form a PVC / FAR blend, and separating the PVC / FAR blend to form a PVC-based powder composition. Blending can be performed by any known blending method.

[0047] The step of isolating the PVC / FAR blend preferably comprises spray drying or freeze drying the PVC / FAR blend to form a PVC-based powder composition.

[0048] In a preferred embodiment, the PVC-based powder composition can be used to manufacture automotive parts so that the parts have improved properties, such as enhanced heat aging properties and low temperature impact performance after heat aging.

[0049] The PVC-based powder composition can be used as a masterbatch for preparing a PVC formulation for manufacturing an article. For example, the PVC-based powder composition can be mixed with another powder PVC (such as S-PVC resin) to prepare a PVC formulation for manufacturing an article. The PVC formulation is suitable for a rotational molding process, preferably a slush molding process.

[0050] The PVC-based powder composition according to the invention allows the amount of plasticizer used in the PVC formulation to be reduced compared to conventional PVC formulations for rotational molding and in particular for slush molding.

[0051] In another aspect of the invention, a PVC formulation may be prepared by blending the PVC-based powder composition with another PVC resin and optionally a plasticizer and / or one or more additional components.

[0052] In the PVC formulation of the present invention, the additional PVC combined with the PVC-based powder composition can be any one or more rigid PVC resins; or can be a PVC material that already contains a plasticizer (i.e., a plasticized PVC material). For example, the plasticized PVC material can be pre-formulated with a plasticizer so that the total concentration of the plasticizer in the composition can generally be greater than 1 weight percent (wt%) and less than 80 weight percent, as described below with respect to the plasticizer. If the additional PVC added to the PVC-based powder composition is not a plasticized PVC, a plasticizer can be added to the formulation.

[0053] PVC resins used in PVC formulations can include, for example, suspension grade PVC, designated by those with "K" values ​​of K56 to K72 in the industry. As known to those skilled in the art, the "K" value is a measure of the molecular weight of the PVC resin based on the measured value of the viscosity of the PVC solution as described in ISO 1628-2 (1998). A higher K value indicates a higher PVC molecular weight. PVC materials of K56 to K72 PVC grades are typically used, for example, to make packaging applications; and film and sheet products for building and construction applications. When preparing PVC formulations, in addition to S-PVC resins, the PVC resins can also include emulsion PVC (E-PVC) resins.

[0054] Alternatively, the additional PVC used in the PVC formulation may include only E-PVC resin. In such embodiments, the PVC resin, the PVC formulation may consist of or consist essentially of E-PVC resin. As used herein, the phrase consisting essentially of E-PVC resin means that the PVC resin in the PVC formulation includes at least 95% by weight of E-PVC relative to the total amount of PVC in the PVC formulation. Preferably, the additional PVC consists of or consists essentially of E-PVC.

[0055] Various one or more conventional plasticizers or compounds can be used in PVC formulations. For example, the plasticizer can be one or more of the following: phthalates, such as diisononyl phthalate (DINP), diisodecyl phthalate (DIDP) and di-2-ethylhexyl phthalate (DEHP); compounds having the following chemical structure (I):

[0056]

[0057] Wherein R in the above structure (I) 1 , R 2 , R 3 and R 4 Each independently is hydrogen or an organic group having 1 or more carbon atoms, and n is 1 to 20; adipic acid esters that can be used at low temperatures, such as diisononyl adipate (DINA) and diisodecyl adipate (DIDA); sebacate esters that can be used at low temperatures, such as dibutyl sebacate (DBS) and di-2-ethylhexyl sebacate (DOS); phosphate softeners and polymer softeners for low migration and anti-extraction; trimellitic acid esters for high temperature resistance; and mixtures thereof. Preferably, the plasticizer includes sebacate esters or trimellitic acid esters.

[0058] The plasticizer may be added to the PVC formulation at a concentration of typically 10 to 60 wt %; 20 to 60 wt %; 30 to 50 wt %; or 40 to 50 wt % based on the total weight of all components in the PVC formulation.

[0059] Preferably, in the method for preparing a PVC formulation having the above components, the concentration of the polyvinyl chloride resin in the PVC formulation may be 20 wt % to 80 wt %; the concentration of the flexible acrylic resin in the PVC formulation may be 1 wt % to 60 wt %; and the concentration of the plasticizer in the PVC formulation may be 10 wt % to 60 wt %, wherein the concentration is relative to the total weight of all components in the PVC formulation.

[0060] During the blending step, various other components may be added to the PVC formulation, including, for example, one or more of heat stabilizers, ultraviolet (UV) stabilizers, antioxidants, and mixtures thereof. Suitable heat stabilizers may be selected from, for example, one or more of metal-based salts and blends thereof, such as alkaline earth metal salts (e.g., calcium or barium metal salts) in combination with cadmium or zinc salts (mixed metal stabilizers); rare earth metal salts, such as lanthanum-based rare earth metal salts; basic and neutral lead salts; and mixtures thereof. Heat stabilizers may also be selected from one or more of the following: metal-free organic compounds (e.g., urea or thiourea); organotin compounds, such as mercaptides, tin carboxylates, and octyltin maleate; and mixtures thereof. Other heat stabilizers added to PVC-based compositions may include, for example, co-stabilizers, such as epoxidized esters; melamine derivatives; and mixtures thereof. Heat stabilizers may be added to PVC formulations at concentrations typically ranging from 0.01% to 2%, from 0.05% to 1.5%, or from 0.1% to 1%.

[0061] The UV stabilizer can be selected from, for example, one or more of the following: UVA (ultraviolet absorber); HALS (hindered amine light stabilizer); and blends thereof; and mixtures thereof. The UV stabilizer can be added to the PVC formulation at a concentration of typically 0.01 wt % to 2 wt %, 0.03 wt % to 1.5 wt %, or 0.1 wt % to 1 wt %.

[0062] The antioxidant may be selected from, for example, one or more of the following: phenols; phosphites; thioesters; amines; and blends thereof; and mixtures thereof. The antioxidant may be added to the PVC formulation at a concentration of typically 0.01 wt % to 2 wt %, 0.03 wt % to 1.5 wt %, or 0.1 wt % to 1 wt %.

[0063] Other optional compounds or additives that can be added to the PVC formulation can include, for example, mold release agents; antistatic agents; foaming agents; surfactants; catalysts; toughening agents; flow modifiers; adhesion promoters; diluents; other stabilizers; other plasticizers, catalyst deactivators; flame retardants; liquid nucleating agents; solid nucleating agents; Ostwald ripening delay additives; and mixtures thereof. When used in a powder PVC formulation, the concentration of the optional compound or additive can generally range from 0 wt % to 20 wt % based on the total weight of the components in the PVC formulation. In one illustration, for example, when the PVC formulation is used for film and sheet applications, the optional additives can be added to the PVC formulation at a concentration of 0 wt % to 10 wt %.

[0064] Various methods can be used to manufacture articles or products including PVC formulations. For example, PVC formulations can be used for rotational molding applications, such as slush molding. Other methods include injection molding, extrusion and thermoforming / calendering applications. PVC formulations can also be co-extruded, overmolded or used in multilayer structures. Preferably, PVC formulations are used in rotational molding.

[0065] Typically, articles or parts can be made using PVC formulations by first producing, for example, a sheet member substrate having a front surface side (also referred to herein as a skin side or A side) and a back side (also referred to herein as a B side); and then producing a foam (e.g., a polyurethane foam) on the B side of the substrate, wherein the skin side of the substrate remains free of other materials and open to the atmosphere. For example, a part made from a sheet member substrate using a PVC formulation can be a soft automotive interior skin that can be prepared by slush molding.

[0066] When the article made of the PVC formulation is a film or sheet member, the thickness of the film or sheet may be in the range of 0.2 millimeters (mm) to 2 mm, for example, 0.4 mm to 1.2 mm or 0.5 mm to 1.0 mm.

[0067] Compared with conventional PVC products, PVC products made according to the above process advantageously have several advantageous properties and benefits. For example, in one embodiment, the PVC products of the present invention exhibit improvements in heat aging. The heat aging properties of PVC products can be measured, for example, by ISO 188 or Ford specification WSS-M4D985-A3 as defined and determined by the procedure described in ISO 37 (2017) for tensile properties. Typically, heat aging can be carried out at 120°C for a time of not more than 1,000 hours (hr), for example, 500hr to 1,000hr. In a preferred embodiment, the PVC product can exhibit a maximum change in tensile strength of not more than or <25%, and a loss in elongation at break of not more than or <50%.

[0068] The PVC article preferably exhibits an improvement in low temperature impact performance after heat aging. The low temperature impact performance properties of the PVC article can be measured, for example, by low temperature flexibility at -40°C, which is defined and determined by the procedure described in Ford specification WSS-M4D985-A3 (2010). Preferably, the PVC article should not exhibit cracking. Alternatively, a method that can be more quantitative and can be used includes a multi-axial impact test at 6.7m / s at -30°C, as described in ISO6603 or ASTM D3763 (2015). Preferably, the PVC article should be 100% ductile. The ductility properties of the PVC article are very important, especially when the PVC article is used for airbags installed in vehicles. PVC preferably has complete ductility, because any brittle failure of the PVC airbag may cause the risk of fragments impacting passengers during the deployment of the airbag.

[0069] The PVC-based powder composition and articles made from the PVC-based powder composition according to the present invention can be used in a variety of applications, including, for example, for slush molding, which is generally used to make soft automotive interior skins. In a preferred embodiment, the PVC-based composition can be used to make dashboards and door panels. For example, a method for making soft skins is described in U.S. Pat. No. 8,674,027.

[0070] Example

[0071] The following examples are provided to further illustrate the present invention in detail but should not be construed as limiting the scope of the claims. Unless otherwise indicated, all parts and percentages are by weight.

[0072] A masterbatch of a PVC-based composition according to the present invention was prepared by sequentially adding the materials in Table 1 below at specific temperatures. The PVC powder was added to a Gunther Papenmeier / Welex blender at room temperature, the power was increased to 15A, TM 181 was added at 125°F, and the lubricant package was added at 150°F. The powder blend was allowed to cool to room temperature before adding Jayflex TM And the temperature was slowly increased to 125° F. The masterbatch had a composition according to Table 1. A powder PVC composition was also prepared.

[0073] Table 1

[0074]

[0075] To simulate zero shear slush molding conditions, preheat the Carver hot press to 392℉ (200℃). Place a small amount of PVC masterbatch in an alumina weighing pan, which is then placed on the Carver hot press platform. Raise the platform so that the weighing pan contacts the upper heating plate. Remove the weighing pan from the hot press after 5 minutes. Then peel the film off the weighing pan.

[0076] Dispersion morphology analysis

[0077] Block face samples were prepared to expose the overall morphology of the modified PVC. Cryosectioning was performed to obtain a flat surface for AFM analysis. Figure 2 AFM tapping mode images of plasticized PVC without FAR are shown. Both height and phase images show uniform PVC as expected. In the phase image, bright islands (crystal-like) of migrating plasticizer are observed. The vertical lines are knife marks produced during microtomy.

[0078] Figure 3 AFM images of blends of 100% pure E-PVC with 50% FAR & plasticizer and 50% PVC masterbatch powder according to the composition of Table 1 are shown. The total amount of FAR in the composition is 16 wt % based on the total weight of the composition. These samples were gel-molded at 392°F for 5 minutes. In these samples, pure E-PVC areas without any FAR particles were observed. It is noteworthy that there is no Figure 2 The migration plasticizer was observed in the FAR particles. The plasticizer was retained in the FAR particles. Islands of semi-aggregated FAR particles were observed to be sparse within the PVC. Closer observation of the aggregates showed that the particles were still isolated in the continuous PVC matrix. This indicates that the masterbatch PVC is compatible with FAR in the presence of the plasticizer. In the phase image, the FAR particles have bright contrast, indicating higher hardness compared to the PVC matrix.

[0079] Figure 4A 50 / 50 blend of PVC / FAR according to the composition in Table 1 is shown, gel molded at 410°F for 5 minutes. This sample preparation produces well dispersed particles throughout the PVC. At this processing temperature, the particles are again in bright contrast to the PVC, indicating a relatively higher hardness than the PVC.

[0080] At a higher temperature of 428°F ( Figure 5 ), the FAR particles were well dispersed again, regardless of the coagulation time (up to 5 minutes). This composition contained a total of 15 wt% FAR, based on the total weight of the composition. The FAR particles showed a dark contrast compared to PVC, indicating that they are softer than the PVC matrix. At a certain threshold (410°F-428°F) temperature, the FAR particles softened relative to the PVC matrix. This is because the plasticizer migrated from the PVC into the FAR particles, making the PVC harder and therefore better performing.

Claims

1. A method for preparing a polyvinyl chloride-based powder composition, the method comprising: a) blending an emulsion of a polyvinyl chloride resin and an emulsion of a flexible acrylic resin to form a polyvinyl chloride resin / flexible acrylic resin blend; as well as b) separating the polyvinyl chloride resin / flexible acrylic resin blend to form the polyvinyl chloride-based powder composition.

2. The method according to claim 1, wherein step a) further comprises blending one or more heat stabilizers, one or more UV stabilizers or one or more antioxidants with the emulsion of the polyvinyl chloride resin and the emulsion of the flexible acrylic resin.

3. The method of claim 1, wherein the polyvinyl chloride resin is present in an amount ranging from 20 wt % to 90 wt %, and the flexible acrylic resin is present in an amount ranging from 1 wt % to 60 wt %, wherein the weight percentages are relative to the total weight of all components in the polyvinyl chloride-based composition.

4. The method according to any one of the preceding claims, wherein step b) comprises spray drying or freeze drying the polyvinyl chloride resin / flexible acrylic resin blend to form the polyvinyl chloride-based powder composition.

5. A polyvinyl chloride-based powder composition prepared by the method according to any one of the preceding claims.

6. A polyvinyl chloride preparation comprising a powdered polyvinyl chloride resin and the polyvinyl chloride-based powder composition according to claim 5.

7. The PVC formulation according to claim 6, further comprising one or more plasticizers.

8. An article made of the polyvinyl chloride-based composition according to claim 5 or the polyvinyl chloride formulation according to claim 6 or 7.

9. The article of claim 8, wherein the article comprises a skin member.

10. The article of claim 9, wherein the skin member further comprises a polyurethane foam backing.

11. A method for preparing an article from a polyvinyl chloride-based powder composition, the method comprising the following steps: 1) preparing a polyvinyl chloride based powder composition by: a) blending an emulsion of a polyvinyl chloride resin and an emulsion of a flexible acrylic resin to form a polyvinyl chloride resin / flexible acrylic resin blend; as well as b) separating the polyvinyl chloride resin / flexible acrylic resin blend to form the polyvinyl chloride-based powder composition; as well as II) blending the polyvinyl chloride-based powder composition with another powdered polyvinyl chloride resin to form a polyvinyl chloride formulation; as well as III) forming an article from the powdered polyvinyl chloride preparation of step II).

12. The method of claim 11, wherein step II) further comprises blending the polyvinyl chloride-based powder composition and an additional powdered polyvinyl chloride resin with at least one plasticizer.

13. The method according to claim 11 or 12, wherein forming the article from the powdered polyvinyl chloride formulation of step II) comprises slush molding.

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