WO2026030300A1 - Cellulose-based glitter in ionomer resins - Google Patents

Abstract

The present disclosure provides directed to a molded article comprising at least 95 wt.% of an ionomer, the ionomer being an at least partially neutralized ethylene acid copolymer; and less than 5 wt.% of cellulose-based glitter disposed within a matrix defined by the ionomer, wherein the cellulose-based glitter comprises cellulose coated with metal and has a size ranging from 1 mm to 3 mm.

Description

CELLULOSE-BASED GLITTER IN IONOMER RESINS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63/677,233 filed July 30, 2024, the contents of which are incorporated in their entirety herein.

TECHNICAL FIELD

[0002] The present disclosure generally relates to cellulose-based glitter for use in the production of molded articles.

BACKGROUND

[0003] Current trends in packaging aesthetics and consumer preferences provide demand for new decorative effects. However, the materials typically used in consumer products, such as perfume caps, do not always meet new regulatory requirements regarding sustainability and material usage.

SUMMARY

[0004] In response to the ongoing demand from for captivating and environmentally responsible decorative solutions, new compositions for molded articles may be desired. One solution is the use of biodegradable glitter, or glitter based on cellulose. This approach meets the most stringent of regulatory requirements, such as the European Union's ban on polymer-based glitters, and also aligns with sustainable practices. The glitter used in the molded articles disclosed herein are sourced ethically and sustainably from natural materials, ensuring biodegradability in water and passing aquatic ecotoxicity analysis.

[0005] According to one embodiment, the molded article comprising at least 95 wt.% of an ionomer, the ionomer being an at least partially neutralized ethylene acid copolymer; and less than 5 wt.% of cellulose-based glitter disposed within a matrix defined by the ionomer, wherein the cellulose-based glitter comprises cellulose coated with metal and has a size ranging from 1 mm to 3 mm. [0006] Additionally, the molded part may have a decorative finish that simulates leaves or particles of natural materials floating inside the part, adding a unique and organic aesthetic obtained using injection molding process to get a thick- walled part made of a transparent resin that can be processed at low temperatures ranging from 160 to 210°C (320 to 410°F) blended with a bio-degradable glitter based on cellulose.

[0007] Additional features and advantages will be set forth in the detailed description that follows and, in part, will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows in addition to the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a TGA curve of the temperature (°C) (x-axis) versus the weight % of sample CGI;

[0009] FIG. 2 is a TGA curve of the temperature (°C) (x-axis) versus the weight % of sample G10; and

[0010] FIG. 3 is a TGA curve of the temperature (°C) (x-axis) versus the weight % of sample G9.

DETAILED DESCRIPTION

[0011] Specific embodiments of the present application will now be described. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the subject matter to those skilled in the art.

[0012] Definitions

[0013] The term “composition,” as used herein, includes a material or mixture of materials which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition. Typically, any reaction products and/or decomposition products are present in trace amounts.

[0014] The term “polymer” refers to a polymeric compound prepared by polymerizing monomers, whether of a same or a different type. The generic term polymer thus embraces the term “homopolymer,” which usually refers to a polymer prepared from only one type of monomer as well as “copolymer,” which refers to a polymer prepared from two or more different monomers.

[0015] “Polyethylene” or “ethylene-based polymer” shall mean polymers comprising greater than or equal to 50% by mole of units derived from ethylene monomer. This includes ethylenebased homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of ethylene-based polymers known in the art include, but are not limited to, Tow Density Polyethylene (TDPE); Tinear Tow Density Polyethylene (TTDPE); Ultra Low Density Polyethylene (ULDPE); Very Low Density Polyethylene (VLDPE); single-site catalyzed Linear Low Density Polyethylene, including both linear and substantially linear low density resins (m- LLDPE); Medium Density Polyethylene (MDPE); and High Density Polyethylene (HDPE).

[0016] “Ethylene acid copolymer” is a polymerized reaction product of ethylene and one or more unsaturated carboxylic acids.

[0017] The term “glitter” as used herein refers to a collection of relatively small reflective particles that come in various shapes, sizes, and colors, often used to add a sparkling or shimmering effect to surfaces and materials. Traditionally, these particles may be made from plastics, metals, or minerals, and are coated with reflective materials to enhance their sparkle. Glitter used in the embodiment disclosed herein may be made from cellulose or other biodegradable contents.

[0018] For the purposes of describing and defining the present invention, it is noted that recitations herein of “at least one” component, element, etc., should not be used to create an inference that the alternative use of the articles “a” or “an” should be limited to a single component, element, etc. For example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise. [0019] It is noted that terms like “preferably,” “commonly,” and “typically,” when utilized herein, are not utilized to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to identify particular aspects of an embodiment of the present disclosure or to emphasize alternative or additional features that may or may not be utilized in a particular embodiment of the present disclosure.

[0020] Embodiments of the present disclosure are directed to a molded article comprising at least 95 wt. % of an ionomer, the ionomer being an at least partially neutralized ethylene acid copolymer; and less than 5 wt. % of cellulose-based glitter disposed within a matrix defined by the ionomer, wherein the cellulose-based glitter comprises cellulose coated with metal and has a size ranging from 1 mm to 3 mm.

[0021] Ionomer

[0022] The ionomer is an ethylene acid copolymer that is partially neutralized by metal cations. This partial neutralization alters the properties of the copolymer, enhancing characteristics such as toughness, flexibility, and resistance to moisture.

[0023] The ethylene acid copolymer is the polymerized reaction product of 70 to 85 wt.% ethylene and 15 to 30 wt.% carboxylic acid containing comonomer, based on the total weight of monomers present in the ethylene acid copolymer. All individual values and ranges are included and disclosed herein. For example, in some embodiments, the ethylene acid copolymer is the polymerized reaction product of from 72 to 85 wt. % of ethylene; and from 15 to 28 wt. % carboxylic acid containing comonomer, based on the total weight of monomers present in the ethylene acid copolymer. In other embodiments, the ethylene acid copolymer is the polymerized reaction product of from 75 to 85 wt. % of ethylene; and from 15 to 25 wt. % of a carboxylic acid containing comonomer, based on the total weight of monomers present in the ethylene acid copolymer. The ethylene acid copolymer may be polymerized according to processes disclosed in U.S. Pat. Nos. 3,404,134; 5,028,674; 6,500,888; and 6,518,365. [0024] Various carboxylic acid containing comonomers may be utilized in the ethylene acid copolymers. For example, the carboxylic acid containing comonomer may comprise a monocarboxylic acid, which may include acrylic acid, methacrylic acid, or both.

[0025] These metal cations involved in the neutralization include but are not limited to, sodium, zinc, calcium, aluminum, potassium, or combinations thereof, among others. These metal ions neutralize a portion of the acidic groups, forming ionic bonds within the polymer matrix.

[0026] Referring to the total acid units neutralized, the calculation of percent neutralization is based on the number of acid units considered to be present, based on the known amount of moles of the carboxylic acid containing comonomer and the number of mole equivalents of alkali metal added. In embodiments herein, from 0.01 mole % to 100 mole % of total acid units of the ethylene acid copolymer neutralized by an alkali metal cation. All individual values and subranges are included and disclosed herein. In further embodiments, the neutralization may range from a minimum of 0.1 mole %, 1.0 mole %, 2.0 mole %, 5.0 mole %, 10.0 mole %, 20.0 mole %, 25.0 mole %, 40.0 mole %, or 50.0 mole %, to a maximum of 30 mole %, 40 mole %, 50 mole %, 60 mole %, 70 mole %, 80 mole %, 90 mole %, or 100 mole % of total acid units may be neutralized.

[0027] In embodiments, the ionomer resin may have a density according to ASTM D792 (incorporated herein by reference in its entirety) from 0.935 g/cm³ to 0.980 g/cm³, or from 0.940 g/cm³ to 0.975 g/cm³ for example.

[0028] In embodiments, the ionomer resin may have a melt index (I2) from 0.01 to 10 dg/min, such as from 0.01 to 0.1 dg/min, from 0.1 to 0.2 dg/min, from 0.2 to 0.3 dg/min, from 0.3 to 0.4 dg/min, from 0.4 to 0.5 dg/min, from 0.5 to 0.6 dg/min, from 0.6 to 0.7 dg/min, from 0.7 to 0.8 dg/min, from 0.8 to 0.9 dg/min, from 0.9 to 1.0 dg/min, from 1.0 to 1.1 dg/min, from 1.1 to 1.2 dg/min, from 1.2 to 1.3 dg/min, from 1.3 to 1.4 dg/min, from 1.4 to 1.5 dg/min, from 1.5 to 1.6 dg/min, from 1.6 to 1.7 dg/min, from 1.7 to 1.8 dg/min, from 1.8 to 1.9 dg/min, from 1.9 to 2.0 dg/min, from 2.0 to 2.5 dg/min, from 2.5 to 3.0 dg/min, from 3.0 to 3.5 dg/min, from 3.5 to 4.0 dg/min, from 4.0 to 4.5 dg/min, from 4.5 to 5.0 dg/min, from 5.0 to 7.0 dg/min, from 7.0 to 10.0 dg/min, or any combination of two or more of these ranges. Melt index (I2) is measured according to ASTM-1238 Condition B (190 °C, 2.16 kg). [0029] Glitter

[0030] The glitter used in embodiments herein is biodegradable glitter, such as cellulose-based glitter. Biodegradable glitter is made from materials that can naturally break down in the environment without leaving residues. The primary component is usually plant-derived cellulose, often sourced from eucalyptus trees, which is then coated with natural or biodegradable colorants and reflective agents. Some biodegradable glitters also incorporate natural mica or other minerals as the reflective component. These materials ensure that the glitter decomposes into harmless substances, making it an alternative to traditional plastic-based glitter.

[0031] In embodiments, the cellulose-based glitter may have a size ranging from 1 mm to 2.5 mm, such as from 1.1 mm to 2.5 mm, 1.2 mm to 2.5 mm, 1.3 mm to 2.5 mm, 1.4 mm to 2.5 mm, 1.5 mm to 2.5 mm, 1.6 mm to 2.5 mm, 1.7 mm to 2.5 mm, 1.8 mm to 2.5 mm, 1.9 mm to 2.5 mm, 2.0 mm to 2.5 mm, 2.1 mm to 2.5 mm, 2.2 mm to 2.5 mm, 2.3 mm to 2.5 mm, 2.4 mm to 2.5 mm, or any combination of two or more of these ranges.

[0032] In embodiments, the cellulose-based glitter may include the following components:

[0033] Table 1 - Example Glitter Composition [0034] Molded Article

[0035] In embodiments, the molded article may be formed by dry blending the ionomer with the cellulose based glitter. In embodiments, the dry blending may be performed in the presence of a compatible oil such as mineral oil or polyethylene glycol. Without being bound by theory, the purpose of this oil helps ensure that the glitter sticks to the surface of the pellets for good homogenization during blending.

[0036] In embodiments, the dry blend may comprise at least 95 wt.% of an ionomer, such as at least 95.5 wt.%, at least 96 wt.%, at least 96.5 wt.%, at least 97 wt.%, at least 97.5 wt.%, at least 98 wt.%, at least 98.5 wt.%, or even at least 99 wt.%.

[0037] In embodiments, the dry blend may comprise less than 5 wt.% of a cellulose-based glitter, such as less than 4.5 wt.%, less than 4.0 wt.%, less than 3.5 wt.%, less than 3.0 wt.%, less than 2.5 wt.%, less than 2.0 wt.%, less than 1.5 wt.%, or less than 1.0 wt.%.

[0038] The dry blend may be heated at a temperature ranging from 160 °C to 210 °C to form a molten polymer material. The molten polymer material may be molded produce the molded article. The molding article may be produced by a number of methods, such as compression molding, injection molding, blow molding, rotomolding, etc and hybrids of extrusion and molding.

[0039] The molded article may be decorative, such as a perfume cap, cosmetic packaging, and other items. In decorative molded articles, the ionomer may be transparent, such that the glitter is disposed and displayed within the matrix of ionomer.

TEST METHODS

[0040] Melt index ( 12)

[0041] Melt index (I2) values were measured in accordance to ASTM DI 238 at 190 °C and 2.16 kg. [0042] Density

[0043] Density measurements were made in accordance with ASTM D792, Method B.

[0044] TGA

[0045] The TGA graphs were made in accordance with ASTM D7426.

EXAMPLES

[0046] The following Examples are offered by way of illustration and are presented in a manner such that one skilled in the art should recognize are not meant to be limiting to the present disclosure as a whole or to the appended claims.

[0047] The materials used in this study are shown in Table 2.

[0048] Table 2 - Reagents

[0049] of Ionomer 1 [0050] Ionomer 1 is a sodium neutralized ethylene acid copolymer having a melt index (I2) of 4.5 dg/min. The ethylene acid copolymer includes 19 wt.% methacrylic acid.

[0051] Ionomer 1 was prepared by standard neutralization techniques, as disclosed in U.S. Pat. No. 3.264.272 (Rees), which is hereby incorporated by reference. The ethylene acid copolymer used in Ionomer 1 was prepared by standard free-radical copolymerization methods, using high pressure, operating in a continuous manner. Monomers are fed into the reaction mixture in a proportion, which relates to the monomer's reactivity, and the amount desired to be incorporated. In this way, uniform, near-random distribution of monomer units along the chain is achieved. Polymerization in this manner is well known, and is described in U.S. Pat. No. 4,351,931 (Armitage), which is hereby incorporated by reference. Other polymerization techniques are described in U.S. Pat. No. 5,028,674 (Hatch et al.) and U.S. Pat. No. 5,057,593 (Statz), both of which are also hereby incorporated by reference.

[0052] Blending and Molding

[0053] Between 2 to 3 kg (4.4 to 6.6 lb) of material were prepared by weighing and feeding them into an open container. First, the pellets of resin were added, then cellulose-based glitter, and a few drops of lubricant such as mineral oil or polyethylene glycol (PEG) were be added. Once all the raw materials were mixed, the container was closed and shaken for 2 to 3 minutes. The shaking can be done manually or using a mechanical shaker for 2-3 minutes.

[0054] Once finished, the blend was fed into the injection molding machine. The injection molding machine had the capacity to mold ionomer resins with a maximum injection pressure of 180 to 200 MPa (26 to 29 kPSI). The mold had an Al mirror polish finish to obtain maximum transparency and gloss. The temperature profile of the injection unit was between 160 and 210 °C (320 and 410 °F). Additionally, the shear was low with a minimum back-pressure (5 to 10 MPa) and RPM between 100 to 150. The mold temperature was between 15 and 20 °C.

[0055] Table 3 below shows the various inventive sample compositions blended with the glitters in Table 2 and Ionomer 1.

[0056] Table 3: Inventive Examples

[0057] FIGS. 1-3 show thermo gravimetric analysis curves (TGA) that depict the change in three example glitters’ mass as a function of temperature under a controlled atmosphere. The TGA curve plots the percentage of mass loss on the y-axis against temperature on the x-axis. This curve shows that the cellulose-based glitters G9 and GIO critical information about the thermal stability, composition, and decomposition temperatures of materials. Key features of a TGA curve can include inflection points corresponding to significant thermal events such as moisture loss, decomposition, oxidation, or the release of volatile compounds.

[0058] FIG. 1 is a comparative example with polyethylene terephthalate-based glitter. FIG. 1 demonstrates that the standard PET glitter has a stable weight of 99.24% (0.76% decomposition) up to around 220°C and 18.56 minutes. The point of inflection of the TGA curve is around 395°C and 36 minutes, showing the thermal resistance for a plastic.

[0059] However, FIGS. 2 and 3 depict cellulose based glitters G10 and G9, respectively. These examples start showing traces of decomposition between 45 and 50°C with a weight of 99.38% (0.62% decomposition) after 0.74 minutes (45 sec). These curves represent poor thermal resistance, and the point of inflection can be considered somewhere around 60 °C and 1.67 minutes (100 sec).

[0060] FIGS. 2 and 3 demonstrate that the cellulose-based glitters ideally decompose at temperatures that are higher than typical ambient temperatures. This prevents premature degradation during normal use, and the glitters remain intact until it reaches a suitable environment for biodegradation, such as a composting facility or natural environment.

[0061] Additionally, FIGS. 2 and 3 demonstrate that with processing temperatures between 160 °C and 210 °C, the cellulose-based glitters will not degrade by more than 15% after 16 minutes. As the process takes less time (around 5 minutes), the cellulose-based glitters will withstand the processing temperatures without reaching the highest amount of decomposition.

[0062] The subject matter of the present disclosure has been described in detail and by reference to specific embodiments. It should be understood that any detailed description of a component or feature of an embodiment does not necessarily imply that the component or feature is essential to the particular embodiment or to any other embodiment. Further, it should be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

[0063] It is noted that one or more of the following claims utilize the term “wherein” as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”

[0064] It should be understood that where a first component is described as “comprising” a second component, it is contemplated that, in embodiments, the first component “consists” or “consists essentially of’ that second component. It should further be understood that where a first component is described as “comprising” a second component, it is contemplated that, in embodiments, the first component comprises 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%, at least 95%, or even at least 99% that second component (where % can be weight % or molar %). [0065] It is also noted that recitations herein of “at least one” component, element, etc., should not be used to create an inference that the alternative use of the articles “a” or “an” should be limited to a single component, element, etc.

Claims

1. A molded article comprising: at least 95 wt. % of an ionomer, the ionomer being an at least partially neutralized ethylene acid copolymer; and less than 5 wt.% of cellulose-based glitter disposed within a matrix defined by the ionomer, wherein the cellulose-based glitter comprises cellulose coated with metal and has a size ranging from 1 mm to 3 mm.

2. The molded article of claim 1 , wherein the ionomer comprises a neutralizing agent selected from sodium, zinc, calcium, potassium, or combinations thereof.

3. The molded article of any preceding claim, wherein the ionomer has a melt index ranging from 0.01 dg/min to 10 dg/min.

4. The molded article of any preceding claim, wherein the ionomer has a density from 0.935 g/cc to 0.980 g/cc.

5. The molded article of any preceding claim, wherein the cellulose-based glitter has a size ranging from 1 mm to 2.5 mm.

6. The molded article of any preceding claim, further comprising less than 0.5 wt.% of the cellulose-based glitter.

7. The molded article of any preceding claim, further comprising mineral oil or polyethylene glycol.

8. The molded article of any preceding claim, wherein the molded article is a decorative article in which the ionomer is transparent.

9. The molded article of any preceding claim, wherein the molded article is a perfume cap.

10. A method of forming the molded article of any preceding claim comprising: dry blending the ionomer with the cellulose based glitter optionally with mineral oil or polyethylene glycol; heating the dry blend at a temperature ranging from 160 °C to 210 °C to form a molten polymer material; and molding the molten polymer material to produce the molded article.