WO2017151555A1

WO2017151555A1 - Single step compounding of organoclay and titanium dioxide for nanocomposite films

Info

Publication number: WO2017151555A1
Application number: PCT/US2017/019844
Authority: WO
Inventors: Feng Chen; Gregory J. Wideman; Mark M. Mleziva
Original assignee: Kimberly-Clark Worldwide, Inc.
Priority date: 2016-02-29
Filing date: 2017-02-28
Publication date: 2017-09-08

Abstract

A method for manufacturing a blended polymer includes feeding separately into an extruder a polyolefin, a filler, a clay powder, and a compatibilizer; mixing in the extruder the polyolefin, the filler, the clay powder, and the compatibilizer; and forming the blended polymer from the resulting mixture using the extruder. A method for manufacturing a blended polymer also includes feeding separately into an extruder a polyolefin, an inorganic filler, a clay powder, and a compatibilizer; mixing in the extruder the polyolefin, the inorganic filler, the clay powder, and the compatibilizer; and forming the blended polymer from the resulting mixture using the extruder.

Description

SINGLE STEP COMPOUNDING OF ORGANOCLAY AND TITANIUM DIOXIDE FOR

NANOCOMPOSITE FILMS

BACKGROUND

The present disclosure relates to a single step compounding/extrusion process for producing pellets that can be used to make a nanocomposite film with white color pigment.

A typical masterbatch approach to producing such films starts with a masterbatch of titanium dioxide blended/compounded with polyethylene resin and other materials, and a separate masterbatch of blended/compounded organoclay powder with other materials.

These are combined in yet another extrusion with additional polyethylene to make

compounded pellets for film.

Rather than using this titanium dioxide "masterbatch" approach where the titanium dioxide is first blended/compounded with the polyethylene resin and then secondly extruded with more polyethylene and a separate organoclay powder/masterbatch to make the compounded pellets for film, this disclosure describes a single step compounding process to make the pellets for film, which combines all of these ingredients in a single step using a twin screw extruder.

SUMMARY

This disclosure is a single step compounding/extrusion process for producing pellets that can be used to make a nanocomposite film with white color pigment.

To create economic value, there was a need to develop one-step processing without using the expensive masterbatch compositions. This material fulfills a technical and business gap by bringing a cost-advantaged composition and process to commercial scale for personal care and other products.

The present disclosure describes a method for manufacturing a blended polymer includes feeding separately into an extruder a polyolefin, a filler, a clay powder, and a compatibilizer; mixing in the extruder the polyolefin, the filler, the clay powder, and the compatibilizer; and forming the blended polymer from the resulting mixture using the extruder.

The present disclosure also describes a method for manufacturing a blended polymer also includes feeding separately into an extruder a polyolefin, an inorganic filler, a clay powder, and a compatibilizer; mixing in the extruder the polyolefin, the inorganic filler, the clay powder, and the compatibilizer; and forming the blended polymer from the resulting mixture using the extruder.

The present disclosure also describes a method for manufacturing a blended polymer including feeding separately into an extruder a polyolefin, titanium dioxide powder, a clay powder, and a compatibilizer; mixing in the extruder the polyolefin, the titanium dioxide powder, the clay powder, and the compatibilizer; and forming the blended polymer from the resulting mixture using the extruder.

Disclosed is a compounding process to directly blend organoclay and Ti0₂ powders in a single pass. This single compounding process produced homogeneous nanocomposite film with good dispersion of the filler phase and improved mechanical properties and economic value.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and aspects of the present disclosure and the manner of attaining them will become more apparent, and the disclosure itself will be better understood by reference to the following description, appended claims and accompanying drawings, where:

Figure 1 illustrates a demonstration of a feeding system for compounding processing using twin-screw extruder;

Figure 2 illustrates a comparison of peak stress in machine direction (MD) for PE2047G/CLAYTONE HY-brand modified montmorillonite (bentonite) clay blend films with different types of whitening masterbatch and powder. The thickness of films is about 0.5mil;

Figure 3 illustrates a comparison of strain at break in machine direction (MD) for PE2047G/CLAYTONE HY-brand modified montmorillonite (bentonite) clay blend films with different types of whitening masterbatch and powder. The thickness of films is about 0.5mil;

Figure 4 illustrates a comparison of elastic modulus in machine direction (MD) for PE2047G/CLAYTONE HY-brand modified montmorillonite (bentonite) clay blend films with different types of whitening masterbatch and powder. The thickness of films is about 0.5mil; and Figure 5 illustrates a comparison of toughness in machine direction (MD) for

PE2047G/CLAYTONE HY-brand modified montmorillonite (bentonite) clay blend films with different types of whitening masterbatch and powder. The thickness of films is about 0.5mil.

Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present disclosure. The drawings are representational and are not necessarily drawn to scale. Certain proportions thereof might be exaggerated, while others might be minimized.

DETAILED DESCRIPTION

While the specification concludes with the claims particularly pointing out and distinctly claiming the disclosure, it is believed that the present disclosure will be better understood from the following description.

All percentages, parts and ratios are based upon the total weight of the compositions of the present disclosure, unless otherwise specified. All such weights as they pertain to listed ingredients are based on the active level and, therefore, do not include solvents or byproducts that can be included in commercially available materials, unless otherwise specified. The term "weight percent" can be denoted as "wt.%" herein. Except where specific examples of actual measured values are presented, numerical values referred to herein should be considered to be qualified by the word "about."

Industry requires opaque, often colored films for some products and packaging. The opacity of the films is used, for example, for printing backgrounds and to obscure the contents of a product or package. For example, the outer cover of a diaper typically has a base color of opaque white for both a clean appearance, to enhance the printing on the outer cover, and to prevent observing the contents of the diaper after being insulted.

Titanium dioxide (Ti0₂) has long been used as a whitening agent in polyfilm applications. Typically, Ti0₂ is supplied by vendors in the form of a masterbatch with the goals of better dispersion in the final film and easier feeding when processed. This kind of masterbatch requires a compounding process to blend Ti0₂ powder and a polyolefin. This compounding step creates additional cost for the final product. The additional costs are exacerbated with the use of organoclay because organoclay in polyethylene is typically manufactured and supplied in the same masterbatch approach. If one then intends to combine Ti0₂ and organoclay, yet another compounding step is required to blend the two masterbatches. In view of the volume of polyfilm manufactured in the United States and around the world, there is a strong commercial need for innovations to consolidate the compounding process for cost and energy savings. In addition to optimizing cost and energy usage in the supply chain, improvement on film mechanical properties is also a benefit desired by polyfilm manufacturers.

The methods described herein eliminate the need for multiple extrusions and blendings/compoundings by the use of a single step compounding process to make the pellets for film. Generally, these methods combine all of the ingredients in a single step using a twin-screw extruder.

This single step process reduces the cost of using multiple masterbatches, allows for tighter control of compositions, and produces films with better mechanical properties. This single step process also eliminates the inclusion of undesired additional components typically present in a masterbatch.

If a nanocomposite film is selected for use in a product or packaging, various levels of opacity could be desired. Nanocomposite film is typically at least translucent.

Ti0₂ can be used as a whitening agent in polyfilm. In one aspect of the present disclosure, Ti0₂ is used directly in its powder form instead of as a component of a

masterbatch. This direct use enables a single-step compounding process for a

nanocomposite film with associated cost and energy savings. By optimizing the feeding system, two types of powdered filler materials (e.g., organoclay and Ti0₂) were able to be blended into a polymer melt stream in a twin-screw extruder in one step. This single-step process achieves a synergistic effect with respect to the mechanical properties of organoclay film with white color. The essential principle is to improve the dispersion of both filler materials in the composite film. It should be noted that although Ti0₂ is used as an example herein, any suitable mineral filler can be used depending on the desired end product.

Instead of feeding a masterbatch including Ti0₂ as a component of the PE melt during the compounding process, Ti0₂ powder is fed through the front end (throat feeder) of a twin- screw extruder. After this initial stage of mixing and blending between the PE and Ti0₂ phases, organoclay powder is added into the blend melt through a side feeder. The blend melt including fillers is then extruded from the extruder and cut into pellets, film, or any suitable form for further use. By effectively using the shear stress provided by the twin-screw extruder, both fillers, Ti0₂ and organoclay, achieved ideal dispersion and synergistically led to a composite film with improved mechanical properties. In other aspects of the present disclosure, both the Ti0₂ and the organoclay can be fed through the throat feeder, both the Ti0₂ and the organoclay can be fed through the side feeder, and the organoclay can be fed through the throat feeder while T1O2 is fed through the side feeder.

The single-step compounding/extrusion process produces pellets that can be used to make a nanocomposite film with white color pigment, or produces directly the nanocomposite film with white color pigment. In other aspects of the present disclosure, the pellets or other output of the process can be used to make films, fibers, injection molded articles, or any other suitable product.

In a specific exemplary aspect of the present disclosure, a blend includes titanium dioxide (Ti0₂) whitener powder, an organoclay powder such as CLAYTONE HY-brand modified montmorillonite (bentonite) clay, a polyolefin resin such as linear low density polyethylene (LLDPE), and a compatibilizer such as FUSABOND E528 anhydride grafted polyethylene. In other aspects of the present disclosure, any other suitable polyolefin can be used, including low density polyethylene, high density polyethylene, and polypropylene.

Even in the color additive industry for polyfilms, there has not been reported the use of organoclay as an additive in the compounding process of a whitening agent such as Ti0₂ for a polyolefin.

For previous organoclay/polyolefin films, Ti0₂ has not been reported to have been added to the organoclay/polyolefin film in a powder form. The feeding system combination including the compounding process for white organoclay film using throat feeding for Ti0₂ and side feeding for organoclay has not been reported.

Materials used also include a polyolefin. One such polyolefin commonly used is polyethylene. Exemplary polyolefins for this purpose can include, for instance, polyethylene, polypropylene, blends and copolymers thereof. In one particular aspect, a polyethylene is employed that is a copolymer of ethylene and an oc-olefin, such as a C₃-C₂₀ oc-olefin or C₃-Ci₂ oc-olefin. Suitable oc-olefins can be linear or branched (e.g., one or more C1 -C3 alkyl branches, or an aryl group). Specific examples include 1 -butene; 3-methyl-1 -butene; 3,3-dimethyl-1 - butene; 1 -pentene; 1 -pentene with one or more methyl, ethyl or propyl substituents; 1 -hexene with one or more methyl, ethyl or propyl substituents; 1 -heptene with one or more methyl, ethyl or propyl substituents; 1 -octene with one or more methyl, ethyl or propyl substituents; 1 - nonene with one or more methyl, ethyl or propyl substituents; ethyl, methyl or dimethyl- substituted 1 -decene; 1 -dodecene; and styrene. Particularly desired oc-olefin co-monomers are 1 -butene, 1 -hexene and 1 -octene. The ethylene content of such copolymers can be from about 60 mole% to about 99 mole%, in some aspects from about 80 mole% to about 98.5 mole%, and in some aspects, from about 87 mole% to about 97.5 mole%. The oc-olefin content can likewise range from about 1 mole% to about 40 mole%, in some aspects from about 1 .5 mole% to about 15 mole%, and in some aspects, from about 2.5 mole% to about 13 mole%.

The density of the polyethylene can vary depending on the type of polymer employed, but generally ranges from 0.85 to 0.96 grams per cubic centimeter ("g/cm³"). Polyethylene "plastomers", for instance, can have a density in the range of from 0.85 to 0.91 g/cm³.

Likewise, "linear low density polyethylene" ("LLDPE") can have a density in the range of from 0.91 to 0.940 g/cm³; "low density polyethylene" ("LDPE") can have a density in the range of from 0.910 to 0.940 g/cm³; and "high density polyethylene" ("HDPE") can have density in the range of from 0.940 to 0.960 g/cm³. Densities can be measured in accordance with ASTM 1505. Particularly suitable ethylene-based polymers for use in the present disclosure can be available under the designation EXACT-brand polymer from ExxonMobil Chemical Company of Houston, Texas. Other suitable polyethylene plastomers are available under the designation ENGAGE-brand polymer and AFFINITY-brand polymer from Dow Chemical Company of Midland, Michigan. Still other suitable ethylene polymers are available from The Dow Chemical Company under the designations DOWLEX-brand polymer (LLDPE) and ATTANE-brand polymer (ULDPE). Other suitable ethylene polymers are described in U.S. Patent Nos. 4,937,299 to Ewen et al.; 5,218,071 to Tsutsui et al.; 5,272,236 to Lai, et al.; and 5,278,272 to Lai, et al., which are incorporated herein in their entirety by reference thereto for all purposes.

Of course, the present disclosure is by no means limited to the use of ethylene polymers. For instance, propylene polymers can also be suitable for use as a semi-crystalline polyolefin. Suitable propylene polymers can include, for instance, polypropylene

homopolymers, as well as copolymers or terpolymers of propylene with an oc-olefin (e.g., C₃- C₂o), such as ethylene, 1 -butene, 2-butene, the various pentene isomers, 1 -hexene, 1 -octene, 1 -nonene, 1 -decene, 1 -unidecene, 1 -dodecene, 4-methyl-1 -pentene, 4-methyl-1 -hexene, 5- methyl-1 -hexene, vinylcyclohexene, styrene, etc. The comonomer content of the propylene polymer can be about 35 wt.% or less, in some aspects from about 1 wt.% to about 20 wt.%, and in some aspects, from about 2 wt.% to about 10 wt.%. The density of the polypropylene (e.g., propylene/oc-olefin copolymer) can be 0.95 grams per cubic centimeter (g/cm³) or less, in some aspects, from 0.85 to 0.92 g/cm³, and in some aspects, from 0.85 g/cm³ to 0.91 g/cm³. Suitable propylene polymers are commercially available under the designations VISTAMAXX-brand polymer from ExxonMobil Chemical Co. of Houston, Texas; FINA-brand polymer (e.g., 8573) from Atofina Chemicals of Feluy, Belgium; TAFMER-brand polymer available from Mitsui Petrochemical Industries; and VERSIFY-brand polymer available from Dow Chemical Co. of Midland, Michigan. Other examples of suitable propylene polymers are described in U.S. Patent No. 6,500,563 to Datta, et al.; 5,539,056 to Yang, et al.; and

5,596,052 to Resconi, et al., which are incorporated herein in their entirety by reference thereto for all purposes.

A compatibilizer such as FUSABOND maleic anhydride grafted polyolefin can also be used. Most pairs of polymers are immiscible with each other, and have less compatibility than would be required to obtain the desired level of properties and performance from their blends. Compatibilizers are often used as additives to improve the compatibility of immiscible polymers and thus improve the morphology and resulting properties of the blend. Similarly, it is often challenging to disperse fillers effectively in the matrix polymer of a composite, or to adhere layers of polymers to each other or to other substrates. A compatibilizer can be any polymeric interfacial agent that facilitates formation of uniform blends of normally immiscible polymers with desirable end properties.

To improve the compatibility and dispersion characteristics of polyolefins, a

compatibilizer is employed in the thermoplastic composition. Typically, the compatibilizer constitutes from about 0.1 wt.% to about 15 wt.%, in some aspects from about 0.5 wt.% to about 10 wt.%, and in some aspects, from about 1 wt.% to about 5 wt.% of the composition. The compatibilizer generally possesses a polar component provided by one or more functional groups that are compatible with the organoclay and a non-polar component provided by an olefin that is compatible with the polyolefin. The olefin component of the compatibilizer can generally be formed from any linear or branched a-olefin monomer, oligomer, or polymer (including copolymers) derived from an olefin monomer. For example, the compatibilizer can include polyethylene-co-vinyl acetate (EVA), polyethylene-co-vinyl alcohol (EVOH), polyethylene-co-acrylic (EAA), etc. in which the olefin component is provided by the polyethylene backbone. In other aspects, the olefin component can be formed from an a-olefin monomer, which typically has from 2 to 14 carbon atoms and preferably from 2 to 6 carbon atoms. Examples of suitable monomers include, but not limited to, ethylene, propylene, butene, pentene, hexene, 2-methyl-1 -propene, 3-methyl-1 -pentene, 4-methyl-1 - pentene, and 5-methyl-1 -hexene. Examples of polyolefins include both homopolymers and copolymers, i.e., polyethylene, ethylene copolymers such as EPDM, polypropylene, propylene copolymers, and polymethylpentene polymers. An olefin copolymer can include a minor amount of non-olefinic monomers, such as styrene, vinyl acetate, diene, or acrylic and non- acrylic monomer. Functional groups can be incorporated into the polymer backbone using a variety of known techniques. For example, a monomer containing the functional group can be grafted onto a polyolefin backbone to form a graft copolymer. Such grafting techniques are well known in the art and described, for instance, in U.S. Patent No. 5,179,164. In other aspects, the monomer containing the functional groups can be copolymerized with an olefin monomer to form a block or random copolymer.

Regardless of the manner in which it is incorporated, the functional group of the compatibilizer can be any group that provides a polar segment to the molecule, such as a carboxyl group, acid anhydride group, amide group, imide group, carboxylate group, epoxy group, amino group, isocyanate group, group having oxazoline ring, hydroxyl group, and so forth. Maleic anhydride modified polyolefins are particularly suitable for use in the present disclosure. Such modified polyolefins are typically formed by grafting maleic anhydride onto a polymeric backbone material. Such maleated polyolefins are available from E. I. du Pont de Nemours and Company under the designation FUSABOND, such as the P Series (chemically modified polypropylene), E Series (chemically modified polyethylene), C Series (chemically modified ethylene vinyl acetate), A Series (chemically modified ethylene acrylate copolymers or terpolymers), or N Series (chemically modified ethylene-propylene, ethylene-propylene diene monomer ("EPDM") or ethylene-octene). Alternatively, maleated polyolefins are also available from Chemtura Corp. under the designation POLYBOND and Eastman Chemical Company under the designation Eastman G series, and AMPLIFY GR Functional Polymers (maleic anhydride grafted polyolefins). In one particular aspect, the compatibilizer is a graft copolymer of polyethylene and maleic anhydride having the structure shown below:

... ...

The cyclic anhydride at one end is chemically bonded directly into the polyethylene chain. This reaction is accomplished under the high temperatures and pressures of the extrusion process.

Referring to Fig. 1 , for example, one aspect of an extruder 10 that can be employed for the purposes of this disclosure is illustrated. As shown, the extruder 10 includes a housing or barrel 20 and twin screws 30, 40 rotatably driven on one end by a suitable drive 50

(typically including a motor and gearbox). If desired, a single-screw extruder can be employed that contains one screw. The extruder 10 generally contains three sections: the feed section 60, the melt section 70, and the mixing section 80. The feed section 60 is the input portion of the barrel 20 where the polymeric material is added through a throat feeder 90. Additional material can be added through side feeder 100. The melt section 70 is the phase change section in which the plastic material is changed from a solid to a liquid. The mixing section 80 is adjacent the output end of the barrel 20 and is the portion in which the liquid plastic material is completely mixed. While there is no precisely defined delineation of these sections when the extruder is manufactured, it is well within the ordinary skill of those in this art to reliably identify the melt section 70 of the extruder barrel 20 in which the phase change from solid to liquid is occurring.

Additional features and pieces of equipment associated with the extruder 10 such as hoppers, openings, feeders, film formers, supply stations, power supplies, dies, cooling systems, pelletizers, and pumps are well known in the art and are not described herein.

Extruded plastic is output, possible for further processing to form a film.

The polymeric components can be processed within the extruder 10 under shear and pressure and heat to ensure sufficient mixing. For example, melt processing can occur at a temperature of from about 75°C to about 280°C, in some aspects, from about 100°C to about 250°C, and in some aspects, from about 150°C to about 200°C. Likewise, the apparent shear rate during melt processing can range from about 100 seconds ¹ to about 10,000 seconds ¹ , in some aspects from about 500 seconds ¹ to about 5000 seconds ¹ , and in some aspects, from about 800 seconds ¹ to about 1200 seconds ¹. The apparent shear rate is equal to 40/nR³, where Q is the volumetric flow rate ("m³/s") of the polymer melt and R is the radius ("m") of the capillary (e.g., extruder die) through which the melted polymer flows.

Once processed in the extruder, the melt blended composition can flow through a die to form an extrudate that is in the form of a strand, sheet, film, etc. If desired, the extrudate can be optionally cooled using any of a variety of techniques. In one aspect, for example, the extrudate is cooled upon exiting the die using a multi-stage system that includes at least one water-cooling stage and at least one air-cooling stage. For example, the extrudate can be initially contacted with water for a certain period time so that it becomes partially cooled. The actual temperature of the water and the total time that it is in contact with the extrudate can vary depending on the extrusion conditions, the size of the extrudate, etc. For example, the temperature of the water is typically from about I CO to about 60 °C, in some aspects from about ^~\ 5°C to about 40 °C, and in some aspects, from about 20 °C to about 30 °C. Likewise, the total time that water is in contact with the extrudate (or residence time) is typically small, such as from about 1 to about 10 seconds, in some aspects from about 2 to about 8 seconds, and in some aspects, from about 3 to about 6 seconds. If desired, multiple water cooling stages can be employed to achieve the desired degree of cooling. Regardless of the number of stages employed, the resulting water-cooled extrudate is typically at a temperature of from about 40 °C to about 100°C, in some aspects from about 50 °C to about 80 °C, and in some aspects, from about 60 °C to about 70 °C, and contains water in an amount of from about 2,000 to about 50,000 parts per million ("ppm"), in some aspects from about 4,000 to about 40,000 ppm, and in some aspects, from about 5,000 to about 30,000 ppm.

After the water-cooling stage(s), the extrudate is also usually subjected to at least one air-cooling stage in which a stream of air is placed into contact with the extrudate. The temperature of the air stream can vary depending on the temperature and moisture content of the water-cooled extrudate, but is typically from about 0 °C to about 40 °C, in some aspects from about 5°C to about 35 °C, and in some aspects, from about 10°C to about 30 °C. If desired, multiple air-cooling stages can be employed to achieve the desired degree of cooling. Regardless of the number of stages employed, the total time that air is in contact with the extrudate (or residence time) is typically small, such as from about 1 to about 50 seconds, in some aspects from about 2 to about 40 seconds, and in some aspects, from about 3 to about 35 seconds. The resulting air-cooled extrudate is generally free of water and has a low moisture content, such as from about 500 to about 20,000 parts per million ("ppm") in some aspects from about 800 to about 15,000 ppm, and in some aspects, from about 1 ,000 to about 10,000 ppm. The temperature of the air-cooled extrudate can also be from about ^~\ 5°C to about 80 °C, in some aspects from about 20 °C to about 70 °C, and in some aspects, from about 25 °C to about 60 °C. If desired, the extrudate can then pass through a pelletizer to form pellets for subsequent processing into the film of the present disclosure. Alternatively, the extrudate can be processed into the film without first being formed into pellets.

Any known technique can be used to form a film from the blended and optionally cooled composition, including blowing, casting, flat die extruding, etc. In one particular aspect, the film can be formed by a blown process in which a gas (e.g., air) is used to expand a bubble of the extruded polymer blend through an annular die. The bubble is then collapsed and collected in flat film form. Processes for producing blown films are described, for instance, in U.S. Patent Nos. 3,354,506 to Raley; 3,650,649 to Schippers; and 3,801 ,429 to Schrenk et al., as well as U.S. Patent Application Publication Nos. 2005/0245162 to

McCormack, et al. and 2003/0068951 to Boggs, et al., all of which are incorporated herein in their entirety by reference thereto to the extent they do not conflict herewith. In yet another aspect, however, the film is formed using a casting technique.

The polymer blends produced by these processes can be converted into breathable and non-breathable thin films, as well as perforated film. The films can be used as a component of personal care products such as outer cover films for baby diapers and child training pants, and baffle films for adult care and feminine care products. The films can also be adhesively bonded with nonwoven substrates to form laminates. Perforated films can be used as a top-sheet layer that contact skin in feminine pads.

Several examples of the disclosure at different processing conditions and in different ratios of ingredients were made, as described below in the examples.

EXAMPLES

The following examples further describe and demonstrate aspects within the scope of the present disclosure. The examples are given solely for the purpose of illustration and are not to be construed as limitations of the present disclosure, as many variations thereof are possible without departing from the spirit and scope of the disclosure.

Materials Used in Examples

1 . DOWLEX EG 2047G polyethylene (herein PE 2047G or PE) purchased from Dow Chemical Company (Midland, Ml). This is a linear low density polyethylene (LLDPE) petroleum-based resin. 2. CLAYTON HY organoclay, a type of organoclay treated with quaternary ammonium solution, was purchased from BYK Additive, Inc. (Gonzales, TX).

3. FUSABOND E528 compatibilizer, an anhydride grafted polyethylene, was purchased from DuPont, USA.

4. AMPACET 1 10313 colorant, a white color & additive concentrates and compounds masterbatch, was purchased from Ampacet Corporation (Tarrytown, NY). Its Ti0₂ content is 65-70 wt.%.

5. AMERICHEM 64222-D70-200 colorant, a white color & additive concentrates and compounds masterbatch, was purchased from Americhem Corporation (Cuyahoga Falls, Ohio). Its Ti0₂ content is 65-70 wt.%.

6. AMERICHEM 01 1 colorant, a white color & additive powder, was purchased from

Americhem Corporation (Cuyahoga Falls, Ohio)

Equipment

ZSK-30 Extruder: The Werner & Pfleiderer (W&P) ZSK-30 extruder is a modular twin- screw compounder. It has a pair of co-rotating screws arranged in parallel. The center distance between the two shafts is 26.2 mm. The extruder has 14 processing barrels, with 13 heated barrels. Three barrels are open barrels. The nominal screw diameters are 30 mm. The actual outer diameters of the screws are 30 mm and the inner screw diameters are 21 .3 mm. The thread depth is 4.7 mm. The lengths of the screws are 1328 mm and the total processing section length is 1338 mm. For the blends with a whitening masterbatch

(Comparative example #1 and Film example #1 ), PE2047G and AMPACET/AMERICHEM masterbatches were fed through two throat feeders for pellets; organoclay CLAYTON HY was fed through side feeder for powders (Figure 1 ). For the blends with whitening powder (Film example #2), PE2047G and AMERICHEM 01 1 colorant were fed through two throat feeders for pellet and powder, respectively (Figure 1 ). The feeding rates of materials are proportional to their composition ratios in the blends. The resultant white PE/organoclay blend strands were cooled along a cooling belt comprising of a mesh belt and a series of cooling fans. The cooled strand was then pelletized and collected for the following film processing. The vacuum is generated by a water-ring pump connected with a separation tank and a condenser.

HAAKE Extruder: The film processing was conducted on a HAAKE RHEOMEX 252p single screw extruder. The screw has a diameter of D = 19.05 mm with aspect ratio L/D = 25. A chill roll was used to cool the polymer as extruded from the cast film die and also to flatten it out to form the thin film. The chill roll settings were adjusted as needed to obtain films with constant dimension, additional gas cooling was set above the die. The residence time was approximately 1 minute during extrusion. All samples were conditioned overnight at 23 ± 2^°C and 50 ± 5% RH prior to mechanical test and characterizations.

Examples to support this disclosure

1 . Comparative example #1 - organoclay film using AMPACET 1 10313 colorant

masterbatch as a whitening agent. The film composition is PE 2047G/CLAYTON HY organoclay/ FUSABOND compatibilizer/AMPACET colorant at 83 : 5 : 2 : 10 ratio.

2. Film example #1 - organoclay film using AM ERIC HEM 64222-D70-200 colorant as a whitening agent. The film composition is PE 2047G/CLAYTON HY organoclay/ FUSABOND compatibilizer/AMERICHEM colorant at 83 : 5 : 2 : 10 ratio.

3. Film example #2 - organoclay film using AMERICHEM 01 1 colorant powder as a

whitening agent. The film composition is PE 2047G/CLAYTON HY organoclay/

FUSABOND compatibilizer/AMERICHEM colorant at 87 : 5 : 2 : 6 ratio.

Comparative Example #1

The blend of PE 2047G, CLAYTON HY organoclay, FUSABOND compatibilizer, and AMPACET colorant masterbatch was compounded at 83:5:2:10 w/w ratios on the ZSK-30 twin-screw extruder. The processing temperatures along the 7-zone extruder were set as follows: 170,180,190,190,190,185, and 180°C. The melt temperature and pressure were approximately 212°C and 240-320 psi, respectively. Compounding speed in the twin-screw extruder was set as 250 rpm. Torque varied throughout the trial from 82-86% of maximum. Compounded pellets were further processed into films on the HAAKE single screw extruder. The resultant films are smooth and white with a slight brownish hint, which comes from the organoclay addition. Figs. 2-5 show the mechanical properties of PE/organoclay films with whitening agent from different vendors and in different forms (masterbatch/powder). The bars labeled "Comparative Example #1 " are results from control sample in this disclosure:

PE/organoclay film using the AMPACET masterbatch as whitening agent, which is currently used in producing commercial polyfilms. It can be seen that the mechanical properties of this sample film are generally similar to or lower than those of the other two white organoclay films.

Film example #1

The blend of PE 2047G, CLAYTON HY organoclay, FUSABOND compatibilizer, and

AMERICHEM 64222-D70-200 colorant was compounded at 83:5:2:10 w/w ratios on the ZSK- 30 twin-screw extruder. Processing conditions were same as comparative example #1 ; the melt temperature and pressure were similar to comparative example #1 as well. The torque reading was 79-84%, slightly lower than comparative example #1 . The resultant films processed from the HAAKE single screw extruder showed the same appearance as the comparative example #1 . Figs. 2, 3, and 5 show that organoclay film with AMERICHEM 64222-D70-200 masterbatch (bar labeled "Film Example #1 ) showed higher peak stress and strain at break compared with the film with AMPACET masterbatch, yet slightly lower elastic modulus (Fig. 4).

Film example #2

In contrast to the two previous examples that used a whitening masterbatch, in this example PE 2047G, CLAYTON HY organoclay, and FUSABOND compatibilizer were compounded with a whitening powder, AMERICHEM 01 1 colorant, at 87:5:2:6 w/w ratios on the ZSK-30 twin-screw extruder. The processing conditions, melt temperature, and torque were the same as film example #1 ; the melt pressure, on the other hand, was slightly increased by 20psi. The resultant films processed from the HAAKE single screw extruder showed the same appearance as the previous two sample films. Interestingly, peak stress and elastic modulus of this sample film are significantly higher than comparative example #1 and film example #1 , as can be seen in Figs. 2 and 4. The toughnesses of these three sample films are similar (Fig. 5). Compared with the organoclay films using a whitening masterbatch, the film with whitening powder showed relatively larger brittleness (lower strain at break), as shown in Fig. 3.

In a first particular aspect, a method for manufacturing a blended polymer includes feeding separately into an extruder a polyolefin, a filler, a clay powder, and a compatibilizer; mixing in the extruder the polyolefin, the filler, the clay powder, and the compatibilizer; and forming the blended polymer from the resulting mixture using the extruder. A second particular aspect includes the first particular aspect, wherein the

compatibilizer is maleic anhydride grafted polyolefin.

A third particular aspect includes the first and/or second aspect, wherein the filler is a colorant.

A fourth particular aspect includes one or more of aspects 1 -3, wherein the colorant includes titanium dioxide.

A fifth particular aspect includes one or more of aspects 1 -4, wherein the colorant is titanium dioxide powder.

A sixth particular aspect includes one or more of aspects 1 -5, wherein the polyolefin is polyethylene.

A seventh particular aspect includes one or more of aspects 1 -6, wherein the polyolefin is linear low density polyethylene.

An eighth particular aspect includes one or more of aspects 1 -7, wherein the clay is modified montmorillonite / bentonite clay.

A ninth particular aspect includes one or more of aspects 1 -8, wherein the filler is an inorganic filler.

A tenth particular aspect includes one or more of aspects 1 -9, wherein the filler is calcium carbonate.

An eleventh particular aspect includes one or more of aspects 1 -10, wherein the filler is a powder.

A twelfth particular aspect includes one or more of aspects 1 -1 1 , wherein the extruder is a twin-screw extruder.

A thirteenth particular aspect includes one or more of aspects 1 -12, further comprising forming the blended polymer into a film.

In a fourteenth particular aspect, a method for manufacturing a blended polymer includes feeding separately into an extruder a polyolefin, an inorganic filler, a clay powder, and a compatibilizer; mixing in the extruder the polyolefin, the inorganic filler, the clay powder, and the compatibilizer; and forming the blended polymer from the resulting mixture using the extruder. A fifteenth particular aspect includes the fourteenth particular aspect, wherein the filler is a colorant.

A sixteenth particular aspect includes the fourteenth and/or fifteenth aspect, wherein the colorant is titanium dioxide powder.

A seventeenth particular aspect includes one or more of aspects 14-16, further comprising forming the blended polymer into a film.

In an eighteenth particular aspect, a method for manufacturing a blended polymer includes feeding separately into an extruder a polyolefin, titanium dioxide powder, a clay powder, and a compatibilizer; mixing in the extruder the polyolefin, the titanium dioxide powder, the clay powder, and the compatibilizer; and forming the blended polymer from the resulting mixture using the extruder.

A nineteenth particular aspect includes the eighteenth particular aspect, further comprising forming the blended polymer into a film.

A twentieth particular aspect includes the eighteenth and/or nineteenth particular aspects, wherein the polyolefin is polyethylene.

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm."

All documents cited in the Detailed Description of the Disclosure are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present disclosure. To the extent that any meaning or definition of a term in this written document conflicts with any meaning or definition of the term in a document incorporated by reference, the meaning or definition assigned to the term in this written document shall govern.

While particular aspects of the present disclosure have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the disclosure. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this disclosure.

Claims

What is claimed is:

I . A method for manufacturing a blended polymer comprising:

feeding separately into an extruder a polyolefin, a filler, a clay powder, and a compatibilizer;

mixing in the extruder the polyolefin, the filler, the clay powder, and the compatibilizer; and

forming the blended polymer from the resulting mixture using the extruder.

2. The method of claim 1 , wherein the compatibilizer is maleic anhydride grafted polyolefin.

3. The method of claim 1 , wherein the filler includes a colorant.

4. The method of claim 3, wherein the colorant includes titanium dioxide.

5. The method of claim 3, wherein the colorant includes titanium dioxide powder.

6. The method of claim 1 , wherein the polyolefin includes polyethylene.

7. The method of claim 1 , wherein the polyolefin includes linear low density polyethylene.

8. The method of claim 1 , wherein the clay powder includes modified

montmorillonite / bentonite clay.

9. The method of claim 1 , wherein the filler includes an inorganic filler.

10. The method of claim 1 , wherein the filler includes calcium carbonate.

I I . The method of claim 1 , wherein the filler is a powder.

12. The method of claim 1 , wherein the extruder is a twin-screw extruder.

The method of claim 1 , further comprising forming the blended polymer into

14. A method for manufacturing a blended polymer comprising:

feeding separately into an extruder a polyolefin, an inorganic filler, a clay powder, and a compatibilizer;

mixing in the extruder the polyolefin, the inorganic filler, the clay powder, and the compatibilizer; and

forming the blended polymer from the resulting mixture using the extruder.

15. The method of claim 14, wherein the filler includes a colorant.

16. The method of claim 15, wherein the colorant includes titanium dioxide powder.

17. The method of claim 14, further comprising forming the blended polymer into a film.

18. A method for manufacturing a blended polymer comprising:

feeding separately into an extruder a polyolefin, titanium dioxide powder, a clay powder, and a compatibilizer;

mixing in the extruder the polyolefin, the titanium dioxide powder, the clay powder, and the compatibilizer; and

forming the blended polymer from the resulting mixture using the extruder.

19. The method of claim 18, further comprising forming the blended polymer into a film.

20. The method of claim 18, wherein the polyolefin includes polyethylene.