WO2015103099A1 - Polyolefin composition including hollow glass microspheres and method of using the same - Google Patents

Abstract

A composition that includes a polyolefin having first repeating units, hollow glass microspheres, a polyolefin impact modifier that is chemically non-crosslinked and free of polar functional groups, and a compatiblizer comprising the first repeating units and second repeating units, which are the first repeating units modified with polar functional groups. Articles made from the composition and methods of making an article by injection molding the composition are also disclosed.

Description

POLYOLEF! COMPOSITION INCLUD NG B.0LL0W GLASS MICROSPHERES A I> METHOD OF

USING THE SAME

Cross-Refereace to R lated Ap lk&tkra

This application claims priority to U.S. Provisional Application No. 1 921 ,848, filed December 30, 2013, the disclosure of which is incorporated by reference in its entirety herein.

Background

Hollow glass microspheres having an average diameter of less than about 500

micrometers, also commonly known as "glass microhubbles", "glass bubbles "hollow glass beads", or "glass balloons'- are widely used in industry, for example, as additives to polymeric compositions. In many industries, hollow glass microspheres are useful, for example, for lowering weight and improving processing, dimensional stability, and ^'flow properties of a polymeric composition. Generally, it is desirable that the hollow glass microspheres be strong enough to avoid being crashed or broken during processing of the particular polymeric compound. Hollow glass microspheres have ^'been incorporated into- polypropylene compositions for certain

applications. See, for example, U.S. Pat. No. 7,365,144 ( a et al).

Summary

In one aspect, the present disclosure provides a composition including or consisting of a poiyolefm comprising first repeating units, hollow glass microspheres, a pOlyolefm impact modifier that is chemically non-crosslinked and free of pol ar functional groups, and a

compatiblizer comprising the first repeating u ite and second repeating units, which are the first repeating units modified with polar functional groups. The hollow glass microspheres are present in a range from 40% to 70% by volume, the polyo!efin impact modifier is present in a range from 20% to 50% by volume, and the eompatihilizer is present in a range from 4% to 12% by volume, based on the total volume of the hollo glass microspheres, the poiyoiefm impact modifier, and the compatibilizer. The composition typically includes greater than ten percent by we ight of the glass, based on the total weight of the composition, which glass may be included in the hollow glass microspheres or non-spherical glass including broken microspheres.

la some embodiments of this aspect, the poiyolefm is other than a polypropylene

homoppjymer. In some embodiments, he composition has a melt flow inde at 190 "C and 2.16 kilograms of at least 3 grams per 10 minutes. In some embodiments, the composition has a notched izod impact strength of at least 60 joules meter. In some embodiments, the poiyolefm comprises polyethylene, and the eompatibilizer comprises ethylene repeating units, in some embodiments, the first repeating units are polypropylene repeating units, and the contpatibllszer comprises propylene repeating units. In these embodiments, the poiyolefm may be a copolymer comprising at least 80% by weight propylene units, in these embodiments, the poiyolefm may be a medium or high impact polypropylene.

In another aspect the present disclosure provides an article comprising such a composition when i is solidified.

In another aspect, the present disclosure provides a masterbatch composition for combining with a poiyolefm comprising first repeating units. The masterbatch comprises includes hollow glass microspheres, a polyolefin impact modifier that is chemically non-erosslinfced and free of polar functional groups, and a campatib-Hzer comprising the first repeating units and second repeating units modified with polar functional groups, in some embodiments, the masterbatch composition contains the poiyolefm comprising first repeating units. In other embodiments, the masterbatch composition does not contain the polyolefin comprising first repeating units. The hollow glass microspheres are present in a. range from 40% to 65% by volume, the poiyolefm impact modifier is present in a range from 20% to 50% by volume, and the eompatibilizer is present in a range from 4% to 15% by volume, based on the total volume of the. hollow glass microspheres, the polyolefin impact modifier, and the eompatibilizer.

in another aspect* the present disclosure provides a method of making an article, the method comprising injection molding the composition described above to make the article.

The compositions according to the present disclosure are suitable, for example, for injection molding to prepare relatively^" low density articles typically having good tensile, flexuraf, and impact strength. For the composition disclosed herein, in many embodiments, at least one of the impact strength (e.g., in some cases, either notched, or unnotehed impact strength), tensile strength, or fiexaral strength of the compositions according to the present disclosure approach or in some eases e ven surprisingly exceed the impact strength of the polyolefin without the addition of hollow glass microspheres. Surprisingly, this improvement was not observed or was not as significant whe -the eompatibilizer included repeating units iffe nt from the first repeating units. in this application, terms such as "a", "an" and "the" are not. intended to refer to only a singular entity, bat include the general class of which specific example may be used for illustration. The terms "a", "an", and "the" are used interchange-ably with the term "at least one". The phrases "at least one of and "comprises at least one of followed by a list refers to any one of me items in the list and any combination of two or more items in the list. All numerical ranges are inclusive of their endpoints and non-integral values between the endpoints.uniess otherwise stated. The terra "crossiinked" refers to joining polymer chains together by covaient chemical bonds, usually via crossiinking molecules or groups, to form a network polymer. Therefore, a chemically non-crossiisked polymer is a polymer that lacks polymer chains joined together by covalent chemical bonds to form a network polymer. A erossKnked polymer is generally characterized by insolubility, but may be sweilabie in the presence of an appropriate solvent. A non-crossllnked polymer is typically soluble in certain solvents and. is typically me!t-processable. A polymer that is chemically non-crossiinked may also be referred to as a linear polymer.

A polar functional group is a functional group that includes at least one atom that is more electronegative than carbon. Common elements of organic compounds thai are more

electronegative than carbon are oxygen,, nitrogen, sulfur, and halogens, in some embodiments, a polar functional group is a functional group that includes at. least one oxygen atom. Such groups include hydroxy! and carbonyl groups (e.g., such as those in ketones, aldehydes, carboxylic acids, carhoxyamides, carboxylic acid anhydrides, and carboxylic acid esters).

The above summary of the present disclosure is not intended to describe each disclosed, embodiment or every implementation of the present disclosure. The description that foilows more particularly exemplifies illustrative embodiments, it i s to be understood, therefore, that the following description should not be read in a: manner that would unduly limit the scope of this disclosure.

^'Retailed Description

Addition of hollow glass microspheres into a polyokfm such as a polypropylene -or high density polyethylene renders them lightweight but usually adversely affects- Impact strength, tensile strength, and flexural strength, impact strength, tensile strength, and flexural strength are all attributes of the poiyoief phase-, and th e addition of hollow glass microspheres dilutes the polyolefln phase. Also, the addition of hollow glass microspheres typically increases viscosity relative to an unfilled polyolefm. An increase in viscosity is a disadvantage, particularly for some polymer processing techniques (e.g.. injection molding).

Impact modifiers, which are typically elastomerio materials, ^'are commonly used in poly olefin compositions and ca ^'be- useful to compensate for the loss in impact strength that, accompanies the addition of hollow glass microspheres. Although impact properties can be improved by the addition of impact modifiers, impact modifiers also tend to decrease the tensile and flexural strength of poiyo!efins. For composites of po.lyolefi.ns and hollow glass microspheres including impact modifiers, the tensile strength and flexural strength are typically greatly reduced relative to the initial polyolefln due to dilution of the strength-inducing polymer phase as described above and the presence of the -soft, rubbery impact modifier. Many impact modifiers are high viscosity, high molecular weight rubber)' materials that increase the viscosity of a composition, which is disadvantageous for some polymer processing techniques. Since both the addition of hollow glass microspheres and impact modifiers increase viscosity, impact-modified, polyoletui- hollo glass microsphere composites with viscosities suitable for injection molding, for example, are .difficult to achieve.

We have found that the simultaneous use of a poiyoiefin impact modifier thai is chemically non-crossfmked and free of polar functional groups and a compatibitizer comprising repeating units modified with polar functional groups in addition to repeating units that are the same as & matrix poiyoiefin in a composition increases the impact strength more efficiently than other combinations of impact modifiers snd compatibilizers while also providing a tensile strength and a fiexural strength in the composition that can approach or even exceed, in some eases, the tensile strength and flexural strength of the matrix poiyoiefin alone. As described above, higher impact strength typically comes a* the expense of lowering the tensile and flexural strength. While not wanting to be bound by theory, it is believed that the functional comparibiHzers in which the functional groups are grafted onto a main polymer chain ^'thai is the same as the matrix polymer can co-crystallize with the polymer phase, which can lead to an improvement in impact,, tensile, and flexural strength. The chemically non-crosslinked impact modifier that is free of polar functional groups and the poiyoiefin providing the matrix of the composition can be selected to have low viscosities, thus providing a composition that is Hght-weig . has excellent impact, tensile, and flexural strength, and is well suited to injection molding.

While including hollow glass, microspheres in polymeric compositions can provide many benefits, the process of adding glass bubbles into a polymer in a manufacturing- process can pose some challenges. Handling glass bubbles may be similar to handling light powders. The hollow glass microspheres ma not be easily contained and difficult to use in a clean environment, it can also be difficult to add m accurate amount -of hollow glass microspheres to the- olymer.

Therefore, the present disclosure provides a maste^'rbatch composition useful, for example, for incorporating hollow glass microspheres into a final, ertd-ssse injection moldabie thermoplastic composition. Delivering the hollow glass microspheres in a masierbatch composition tean eliminate at least some of the handling difficulties encountered during manufacturing.

Examples of polyolefins useful for the compositions according to the present disclosure include those made from monomers having the general structure CHj-CMR¹⁰, wherein R^{, c<} is a hydrogen or alkyl. In some embodiments, R^1C having up to 10 carbon atoms or from one to six carbon atoms. The first, repeating units of such polyolefins would have the general formula - CMa-CHR⁵⁰]-, wherein Rⁱ⁰ is defined as in any of the aforementioned embodiments. Examples of suitable polyolefins include polyethylene; polypropylene; poly (!-huteoe); poly (3- methylbutene; poly (4-me hylpentene); copolymers of ethylene with propylene, 1 -butene, I - hexene, ! -octene, 1-decene, 4-memyl-l -pentene, and 1-ociadecene; and blends of polyethylene and polypropylene. Typically, the compositions according to the present, disclosure comprise at least one of polyethylene or polypropylene, it should: be understood that a polyolefm comprising polyethylene may be a polyethylene bomopo-lymer or a copolymer containing ethylene repeating units. Similarly, it should be understood that a polyolefm comprising polypropylene may be a polypropylene homopolymer or a copolymer containing propylene repeating units. T he pol olefm comprising at least one of polyethylene or polypropylene may also be part a blend of different poiyoiefins that includes at least one of polypropylene or polyethylene. Useful polyethylene polymers include high density polyethylene (e.g., those having a density of such as from 0.94 to abotn 0.98 g cm³) and linear or branched low-density poiyethylenes (e.g. those having a density of such as from 0,89 to 0.94g/cm^$), Useful polypropylene polymers include low impact, medium impact, or high impact polypropylene. A high impact polypropylene may be a copolymer of polypropylene including at least^' 80, 85, 90, or 95% by weight propylene repeating units, based on the weight of the copolymer. these embodiments, it should be understood that the first re eating units are those most abundan ^'in the copolymer. The polyoletin may -comprise mixtures^' of stereoisomers of such polymers (e.g., mixtures of isotactic polypropylene and atactic polypropylene). Suitable polypropylene can be obtained from a variety of commercial sources, for example, LyonddlBaseiL Houston, TX, under the trade designations "PRO-FAX" and "HiFAX", and from Pinnacle Polymers, Garyvii^'le, LA, .Under the trade designation "PINNACLE". In some embodiments, the first repeating units in the polyolefm are propylene repeating units, in some embodiments, the repeating units in the polyolefm consist of propylene repeating units. In some embodiments, the first repeating units in the polyolefm are ethylene repeating units, in some embodiments,_, the po!yoiefin is a polyethylene. In some embodiments, the repeating units in the polyolefm consist of ethylene repeating units, in some embodiments, the polyethylene is high density polyethylene. Suitable polyethylene can be obtained from a variety of commercial sources, for example, Braskern S. A., Sao Paolo, Brazil.

He polyolefm may be selected to have a relatively low viscosity as measured by melt flow index, in some embodiments, the polyolefm has a melt flow index at 230 ^*C and 2.16 kilograms of at least 3 grams per 10 minutes (in some embodiments, at least 5, 10, 15, 20, 25, 30, 35, 40, or 50 grams per 10 minutes). The melt flow index of the polyoletin is measured by ASTM D1238 - 13: Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion

Plastometer,

In the final (e.g., let-down) composition suitable for injection molding articles, the polyoletin comprising first repeating units is typically the major component of the compositions according to the present disclosure and/or useful in the methods according to the present disclosure, in general, the pofvotefhi provides at least 50 percent by weight, based on the total weight of the composition. In some embodiments, the polyolefln comprising first repeating units is present in a range from 50 percent to 75 percent, 55 percent to 70 percent, or 60 percent to 70 percent by weight, based on the total weight of the compos it JOB .

.A masierbatch composition according to the present disclosure, may or may not contain the poiyolefm comprising first repeating units. In some embodiments, the masierbatch comprises the polyolefln comprising the first repeating units, but at a lower percentage than in the let-down compositions suitable for injection molding described above, in some embodiments, the masierbatch comprises the polyolefln in an amount up to 5, 4, 3, or 2 percent by weight, based on the total weight of the masterbatch. The process of combining a masierbatch with other compatible materials is commonly referred to as "letting down" the masierbatch. In the present disclosure, the composition that is made .from the masierbatch can also be -referred to as the letdown composition, A composition useful for letting down a masterbatch composition typically includes the poiyolefm In a sufficient amount to make the let-down ^'composition described above.

The eompatibilizer includes the same repeating units, which are the first repeating units, as the poiyolefm in the compositions according to the present disclosure. The compatibilizer-also includes -second repeating units, which. are the first repealing units modified with pola^'f Functional groups. In some embodiments, the polar functional groups include- male-ie anhydride, csrboxy!ic acid groups, and hydroxy! groups. In some embodiments, the eompatibilizer is a maleic anhydride-modified polyolefin. When the polyolefln in the composition comprises polypropylene, the eompatibilizer is a maleic anhydride-modified polypropylene. When the polyolefin in the composition comprises polyethylene,_. t e eompatibilizer is a maleic anhydride-modified polyethylene. The eompatibilizer is added to the composition in an amount sufficient to improve the mechanical properties of the -composition.. The level of grafting of the polar functional groups (e.g., the level of grafting of maleic anhydride in the modified polyolefln may be in a range from about. 0.5-3%, 0.5-2%, 0.8-1.2%, or about ]%),

In a let-down composition, the eompatibilizer may be present in the composition in an amount _.greater than two percent based on t he total weight of the composition. In some embodiments, eompatibilizer is present in the composition in amount of at least 2.5, 3, 3,5, or 4 percent, based on the toted weight of the composition, in let-down composition, the

eompatibilizer may be present in the composition in an amount greater than 1 .5 percent, based on the- total volume of the composition, in some embodiments, eompatibilizer is present in the composition in amount of at least in a range from 1 .5 percent to 4 percent or 2 percent to 4 percent, based on the total volume of the composition . In a masterbatch composition. Ins c-ompatabiKzer may be present in a range from 4% to 15% by volume, in some embodiments, 10% to 15% by volume, based on the total volume of the masterbatch composition. A composition for letting down the masterbatch may also include 4% to 15% by volume, some embodiments, 10% to 15% by volume compatibilizer, based on the total weigh tof the composition for letting down the masterbatch.

Example ! 2, below, describes a, polypropylene composition thai includes a polypropylene compatibilizer. In comparison to Comparative Example 7E, when the compatibilizer is made from a polyethylene, and therefore does not have the same first repeating units as the

polypropylene, the composition has inferior notched impact strength, tensile strength, and f!exural strength than when the compatibilizer comprises polypropylene repeating units {that is, the same fust repeating units as- the poiyolefin). The effect is even more pronounced for a higher impact polypropylene as shown by a comparison of Example 30 and Comparative Example ISA in Table 19 and for a high density polyethylene as shown by a comparison of Example 3 and Comparative Example I B in Table 4. In comparison to Comparative Example I B, when the compatibilizer is made from a polypropylene, and therefore does not have the same first repeating unit as the polyethylene, the composition has inferior tensile strength and flex-ural strength and far inferior notched impact sireghth than when the compatibilizer comprises polyethylene repeating units (that is, the same .first repeating. units as the poiyolefin).

The impac ^'.-modifier also is a poiyolefin. is chemically non-crosslinked, and is free of polar functional gro s. For -example, the impact, modifier is free of any of the polar functional groups described above in connection with the compatibilizer. In some embodiments, the: impact modifier includes only carbon-carbon and carbon -hydrogen bonds, in some embodiments, the poiyolefin impact modifier is an ethylene propylene elastomer, an ethylene octene elastomer, an ethylene propylene diene elastomer, an ethylene propylene octene elastomer, polybutadiene, a butadiene copolymer, polybutene, or a combl-nation thereof. In some embodiments, the poiyolefin impact modifier is an ethylene octene elastomer.

The impact modifier may be selected to ^'have a relatively low viscosity as measured by melt flow index. A combination of impact modifiers having different melt flow indexes may also be useful. In some embodiments, at least one of the poiyolefin impact modifiers has a melt flow index at 190 and 2, 16 kilograms of at least 10 grams per 1.0 minutes (in some embodimeitts, at least 1 1, 12, or 13 grams per 10 minutes). The melt flow index of the impact modifiers and the poiyolefin is measured by ASTM D 123.8 - 13: Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion. Piastometer.

Other common types of impact modifiers such as ground rubber, core-shell particles, fuoetionalized elastomers available, for example, from. Dow Chemical Company, Midland, Ml, under the trade designation "AMPLIFY G -2^'16", and particles available, for example, from Akzo Nobel, Amsterdam, The ^'Netherlands, under the trade designation "EXPANCEL" are at least one of chemically crossimked o .fi ictkma!ized and are not included is the compositions according to the present disclosure. Many of these impact modifiers increase the viscosity of a composition, making the composition less suitable for some polymer processing techniques (e.g., injection molding), In addition, "EXPANCEL" particles and similar particles require more strict thermal control and more precise handling than the polyoiefin impact modifiers described herein, which can present challenges during processing.

The impact modifier can be added to the composition according to the present disclosure in an amount sufficient to improve the impact strength of the composition.

In let-down composition, the impact modifier may be present in the composition m a range from 7.5 percent to 25 percent by volume, based on the total volum of the composition. In some embodiments, impact modifier is present in the composition in mount of at least 10, 12, 14, 15, or .16 percent and up to about 20 percent by volume, based on the total volume of the composition. Less impact .modifier may be required with a lower level of .hollow glass microspheres. A compositio for letting down a masterbateh may also include the impact modifier i any suitable range (e.g., any of the ranges described above) depend ing on the desired final composition.

n a masterbateh composition, the impact modifier may be present in the composition in a range from 50 percent to 75 percent by volume, based on the total volume of the ^'composition. In some embodiments, impact modifi er is present in the masterbateh composition in ^'amount of at least 50, 55, or 60 percent and up to about 65, 70, or 75 percent by- volume, based on the total volume of the composition, in some embodiments of a masterbateh composition, the impact modifier is- resent in & range from 60 to 70 percent by v lume;, based on the total volume of the composition.

Hollow glass microspheres useful in the compositions and methods according to the present disclosure can be made by techniques known in the art (see, e.g., U. S. Pat, Nos. 2,978,340 (Veatch et al.); 3,030,215 (Veatch et at.); 3,129,086 (Veatch et a!.); and 3,230,064 (Veatch et al); 3,365,315 (Beck et ah); 4,391 ,646 (Howeil); and 4,767,726 {Marshall); and U. S. Pat. App. Pub. No. 2006/0122049 (Marshall et. al). Techniques for preparing hollow glass microspheres typically include heating milled frit, commonly referred to as "feed", which contains a blowing agent (e.g.. sulfur or a compound of oxygen and sulfur). Frit can be made by heating mineral components of glass at high temperatures until molten glass is formed.

Although the frit and/or the fee may have any composition that is capable of forming a glass, typically, on a total weight basis, the frit comprises from 50 to 90 percent of Si(>2, rom 2 to 20 percent of alkali metal oxide, from 1 to 30 percent of EM^") , from 0.005-0.5 percent of sulfur (for example, as elemental sulfur, sulfate or sulfite), from 0 to 25 percent divalent metal oxides (for example, CaO, MgG, Ba.O, SrO, ZnO. or PbO), from 0 to 10 percent of tetravaient metal oxides other than S.O2 (for example, T5O2., MnC^, or ZrC>2)_s from 0 to 20 percent of bivalent metal oxides (for example, AbO-}, Ψ&2® _> or S02O ), from 0 to 10 percent of oxides of pentavalent atoms (for example, P2P or V2O5), and from 0 to 5 percent fluorine (as fluoride) which may act as a fluxing agent to facilitate melting of the glass composition. Additional Ingredients are useful in frit compositions and can be included in the frit, for example, to contribute particular properties or characteristics (for example, hardness or color) to the resultant glass bubbles.

In some embodiments, the hollow glass microspheres useful in the compositions and methods according io the present disclosure have a glass composition comprising more alkaline earth metal oxide than slkali metal oxide, in some of these embodiments, the weight. ratio of alkaline earth metal oxide io alkali metal oxide is in a range from 1.2: 1 to 3: 1. in some embodiments, the hollow glass microspheres have a glass composition .comprising B2O3 in a range from 2 percent to 6 percent based on the total weight of the glass bubbles, in some embodiments, the hollow glass microspheres have a glass composition comprising up to 5 percent by weight AI2O3, based on the total weight of the hollow glass microspheres. In some embodiments, the glass composition is essentially free of AbCH. "Essentially free of AI2O3" may mean up to 5. 4, 3, 2, 1, 0.75, 0.S, 0,25, or 0.1 percent by weight AI2O3. Glass compositions that are "essentially free of AbOj" also include glass compositions ha ing no AbO*. Hollow glass microspheres . useful for practicing the present disclosure may have, in some embodiments, a chemical composition wherein at least 90%, 94%, or even at least 97% of the glass comprises at least 67% Si¾ {e.g., a range of 70% to 80% SiO>), a range of 8% to 15% of an alkaline earth metal oxide (e.g., CaO), a range of 3% to 8 of an alkali metal oxide (e.g., ajO), a range of 2% to 6% !¾0;?, and a range of 0.125% to 1.5% SO3. In some embodiments, the glass comprises in a range from 30% to 40% Si, 3% to 8% a, 5% to 1 1% Ca, 0.5% to.2% B, and 40% to 55% O, based on th total of the glass composition.

The "average true density" of hollow glass microspheres is the quotien obtained by dividing the mass of a sample of hollow glass microspheres by the true volume of that mass of hollow glass microspheres as measured by a gas pycnometer. The "true volume" is the aggregate total volume of the hollow glass microspheres, not the bulk volume. The average true density of She hollow glass microspheres useful for practicing the present disclosure is generally at least 0.30 grams per cubic -centimeter (g ec), 0, 5 g cc, or 0.38 g/ec, in some embodiments, the hollow glass microspheres useful for practicing the present disclosure have an average true density of up to about 0.65 g/cc. "About 0.65 g/cc" means 0.65 g;/cc ± five percent, in some of these

embodiments, the average true density of the hollow glass microspheres is up to 0.6 g/cc or 0.55 g/cc. For example, the average true de sity of the hollow glass microspheres disclosed herein may be in a range from 0.30 g/cc to 0,65 g/cc, 0.30 g/ce to 0.6 g/cc, 0.35 g/cc to 0.60 g cc, or 0.35 g/cc to 0.5.5 g/cc. Hollow glass microspheres having any of these densities can be useful for lowering the density of the composition according to the present disclosure, relative to polyolefin compositions that do not contain hollow glass microspheres.

For the purposes of this disclosure, average true density is measured using a pycnometer according to ASTM Ό2840- 69, "Average True Particle Density of Hollow Microspheres". The pycnometer may be obtained, for example, under the trade designation "ACCUPYC 1330

PYCNOMETER" from Micromer cs, Norcross, Georgia, or under the trade designations "PE TAPYC OMETER" or "ULTRAPYCNOMETER 1000" from Formanex, inc., San Diego, CA, Average iroe density can typically be measured with an accuracy of 0,001 g cc. Accordingly, each of the density values provided above can be ± five percent.

A variety of sizes of hollow glass microspheres may be useful. As used herein, the term size is considered to be equivalent. with the -diameter and height of the hollow glass microspheres. In some embodiments, the hollow glass microspheres ears have a median size by volume in a range from 14 to 45 micrometers (in some-embodiments from I S to 40 micrometers, 20 to 45 micrometers, or 20 to 40 micrometers). The median size is also called the D50 size, where 50 ^•percent by volume of the/hollow glass microspheres in the distribution are smaller than the Indicated size. For the purposes, of the present disclosure, the median size. -by volume is determined by laser light diffraction by dispersing the hollo glass microspheres in deaerated, deiomxed water. Laser light diffraction particle size analyzers are available, for example, under the trade designation "SATURN DIGISIZER" rom Mieromerities. The _: size distribution of the hollow glass microspheres useful for practicing the present disclosure may be Gaussian, normal, or hon-normai. Non-normal distributions- may be unim-odal or multi-modal (e_>g,, himodai).

The hollow glass microspheres useful in the compositions and methods according to die present disclosure typically need to be strong enough to survive the injection molding process. A useful hydrostatic pressure at which ten percent by volume of the hollow glass microspheres collapses is at least about 20 (in some embodiments, at leas about 38, 50, or 55) raegapascals (MPa). "About 20 Pa" means 20 MPs £ five percent. In some embodiments, a hydrostatic pressure at which ten percent by volume of the hollow glass microspheres collapses can be at least 100, 1 10, or 120 MPa. In some embodiments, a hydrostatic pressure at which ten percent, or twenty percent by volume of the hollow glass microspheres collapses is up to 250 (in some embodiments, up to 210, 1 0, or 170) MPa. The hydrostatic pressure at which ten percent by volume of hollow glass microspheres collapses may be in a range from 20 MPa to 250 MPa, 38 MPs to 210 MPa, or 50 MPa to 210 MPa. For the purposes of the present disclosure, the collapse strength of the hollow glass microspheres is measured on a dispersion of the hollow glass

microspheres in glycerol using ASTM 03102 -72 "Hydrostatic Collapse Strength of Hollow Glass Microspheres"; with the exception that the sample size (in grams} is equal to 10 times the density of the glass bubbles. Collapse strength can typically be measured with an accuracy of about five percent. Accordingly, each of the collapse strength values provided above can be ½ five percent.

Hollow glass microspheres useful for practicing the present disclosure can be obtained commercially and include those marketed by 3M Company, St. Paul, MN, under the trade

designation "3M GLASS BUBBLES" (e.g., grades S60, S60HS, 1M30K, 1M16K, S38HS, S38XHS, 42HS, 46, and HSQ 10000). Other suitable hollo glass microspheres can be obtained, for example, from Potters Industries, Valley Forge, PA, (an affiliate of PQ Corporation) under the trade designations "SPHfiRiCEL HOLLOW GLASS SPHERES" (e.g., grades H OPS and 6ΌΡ18) and "Q-CEL HOLLOW SPHERES" (e.g., grades 30, 6014, 6019, 6028^', 6036, 6042, 6048, 501 , 5Θ23, and 5028), from Siibrieo Corp., Hodgkins, IL under the trade -designation "S!L- CELL" (e.g., grades SIL 35/34, SIL-32, SIL-42, and SIL-43), and from Sisos eel Maanshan Inst, of Mining Research Co., Maanshan, China, under the trade designation "Y8000". In some embodiments, hollow glass microspheres useful for practicing the present disclosure may be selected to- have crush strengths of a least about 28 MPa. 34 MPa, 41 MPa, 48 MPa, or 55 MPa for 90% survival.

in a let-down (i.e., final) composition suitable for injection molding,, for example, the hollow glass microspheres are typically present in the composition disclosed herein at a level of at least 5 percent by weight, based on the total weight of the composition. In some embodiments, the hollow glass microspheres are present m th composition at least at 10, 12, or 13 percent by weight based on the total weight of the composition. In some embodiments, the hollow _.glass

microspheres are present in the composition at a level of up to 30, 25, or 20 percent by weight, based on the total weight of the composition. For example, the hollow glass microspheres may be present in the composition in a range from 5 to 30, 10 to 25, or 10 to 20 percent by weight, based on the total weight of the composition.

While in the compositions according to the present discosure, which include impact modifier, compatibilizer, and hollow glass microspheres as described above a of their embodiments, the presence of each of these is critical to the performance of the final composition. As shown throughout the examples, below, while the addition of an impact modifier can improve the impact strengt of a composition including a poiyolefm and hollow glass microspheres, it typically does so at the expense of tensile strength and llexural strength. The addition of a c-ompaitbiiizer to these compositions typically significantly enhances the tensile strength, flexuraf strength, and impact strength. As shown in Table 10, the presence of cornpatibilizers does not significantly change the impact strength of polypropylene containing hollow glass microspheres in the absence of an impact modifier. Surprisingly, the improvement in impact strength when a compatihiiizer is used In the presence of an impact modifier does not occur in the absence of hollow glass microspheres.

The composition according to the present disclosure and/or useful for practicing the method disclosed herein, which includes the olyolefm comprising first repeating units, the hollow glass microspheres, the polyo!efin impact modifier, and the eo pstibi!izer as described above in any of their embodiments has 8 melt flow index that renders it suitable for injection molding. Typically, the composition has a melt flow index at 190 ^*C and 2. 6 kilograms of at least 3 grams per 19 minutes (in some embodiments, at least 5, 10, 15, 20, 25, 30, 35, 40, or 5 .grams per 10 minutes), in some embodiments;, the composition has a melt flow index at 190 ^"C and 2.16 kilograms of at least 3.5 grams per 10 minutes (in .some embodiments, at least 4, 4.5, or 50 grams per 1 minutes). The melt flow index of the polyo!efm is measured by ASTM D1238 - 13;

Standard Test Method for Melt, Flow Rates of Thermoplastics by Extrusion Plastometer.

In some embodiments: of the composition according to the present disclosure, the hollow glass microspheres may be treated with a coupling agent to enhance the interaction between the hollow glass microspheres and the polyo!efi s matrix. In other embodiments, a coupling agent can be added directly to the composition. Examples of useful coupling agents include zirconates, silan.es, or titanaies. Typical titanate and zirconate coupling agents are known to those skilled in the art and a detailed overview of the uses and selection criteria for these materials can be found in Monte, SJ., enric Petrochemicals, Inc., "Ken-React® Reference Manual - Titanate,. Zirc aate and Aluminate Coupling Agents", Third Revised Edition, March, 1995. If used, coupling agents are commonly included in an amount of about 1 % to 3% by weight, based on the total weight of the hollow glass microspheres in the composition.

Suitable sil&nes are coupled to glass surfaces through condensation -reactions to form siloxane linkages with the siliceous glass. This treatment renders the filler more wet-able or promotes the adhesion of materials to the hollow glass microsphere surface. This provides a mechanism to bring about covalent, ionic or dipole bonding between hollow glass microspheres and organic matrices. Silane coupling agents are chosen based on the particular functionality desired. Another approach to achieving intimate hollow glass icrosphere-polymer interactions is to functional sze the surface of microsphere with a suitable coupling agent thai contains a polymerizable moiety, thus incorporating the material directly into the polymer backbone. Examples of pofymerizable.moiedes are materials that contain olefinic functionality such as styrenic, vinyl (e.g., vinyltriethoxysilane, yiayItri(2-methoxyethoxy) silane), acrylic and methacrylic moieties (e.g., 3-«5etacry!roxypropyU?rt«ethoxysjlane>. Examples of useful silanes thai may participate in vulcanization crosslinking include S-mereaptopropy rimethoxysilane, !s tj-iethoxysi!ipropyl)tetrasu!.fane (e.g., available under the trade designation "Si-69" ftom Evonik Industries, Wesseling, Germany), and thiocyanatopropyltriethoxysilane. Still other useful silane coupling agents may have amino f nctional. roups (e.g., N«2-(aminoethyi)-3- amiRopropyltrimethoxysilane and (3>aminopropyl)frimethoxysilane). Coupling agents useful for peroxide-cured rubber compositions typically include vinyl silanes. Coupling agents useful for sulfur-enred rubber compositions typically include mercapto or po!ysu!fido silanes. Suitable silane coupling strategies are outlined in Silane Coupling Agents: Connecting Across Boundaries, by Barry Arkles, pg 165 - 189, Gelest Catalog 300G-A Silanes and Silicones: Geles ltic. MorrisvUie. PA.

Although coupling agents are useful in some embodiments, advantageously, the compositions according to the present disclosure provide good mechanical properties even in the absence of coupling agents. The mechanical properties achieved may understood fay a person skilled in the art to be due to good adhesion between the hollow glass microspheres and the polyo!efin matrix. Accordingly, in some embodiments, the hollow glass microspheres in the compositions according to the present disclosure are not treated with a silane coupling agent. Further, in some embodiments, compositions according to the present disclosure are substantially •free, of a -silane coupling agent. Compositions substantially free of silane coupling agents may be free of silane coupling agents, or may have silane coupling agents present at a level of less than 0.05, 0.0 h 0.005, or 0.001 percent by weight, based on the total weight of the composition.

In some embodiments, the compositions according to and or useful in the method according to the present disclosure includes one or more stabilizers (e.g.. antioxidants or hindered amine light stabilizers (HALS)). For example, any of the compositions, masterbateh compositions, or the let-down compositions described herei n can include one or more of such stabilizers.

Examples of useful antioxidants include hindered phenol -based compounds and phosphoric acid ester-based compounds (e.g., those available from BASF, Fiorham Park-NJ, under the trade designations "IRGANOX" and "!RGAFOS" sueh. as "IRGANOX 1076" and "IRGAFOS 168", those available from Songwon fed. Co, Uisan, Korea, under the trade designations "SONGNOX", and butylated hydroxytoluene (BHD). Antioxidants, when used, can be present in an amount from about 0.00.1 to 1 percent by weight based on the total weight of the composition. HALS are typically compounds that can scavenge free-radicals, which can result, from photodegradation or other degradation processes. Suitable HALS include decanedioic acid, bis (2,2.6,6-tetramethyl- 1- (ociy!oxy)-4-piperidiny3)es er. Suitable HALS include those available, for example, from BASF under the trade designations "TINWIN" and "C.H1MASSORB". Such compounds, when used, can be present in an amount from about 0,001 to I percent by weight based on the total weight of the composition.

Reinforcing filler may be ^'Useful in the composition according to and/or useful in the method according to the present disclosure. For example, any of the compositions, masterbatch compositions, or the Jet-down compositions described herein can include one or more of such reinforcing fillers. Reinforcing filler can be useful, for example, for enhancing the tensile, flexural, and/or impact strength of the composition. Examples of useful reinforcing fillers include silica (including nanosilica). other metal oxides, metal hydroxides, and carbon black. Other useful fillers include glass fiber, woIJastonite, talc, calcium carbonate, titanium dioxide (including nano- titanium dioxide), wood flour, other natural fillers and fibers (e.g., walnut shells, hemp, and corn silks), and clay (including nano-cfay).

However, in some embodiments, the -presence of silica in_. the composition according to the present disclosure can lead to an undesirable increase in the density of the composition.

Advantageously, the compositions according^' to^' the present disclosure and/or useful in the methods according to the present disclosure provide good mechanical properties even in the absence of reinforcing fillers. As shown in the Examples,, below, it has been found that compositions disclosed herein have high tensile, flexural, and impact strength even in the absence of silica filler or other reinforcing filler. Accordingly, in some embodiments, t e composition is free of reinforcing fH!er or contains up t 5, , 3, 2_> or I percent b weight reinforcing filler, based on the total weight of the composition. For example, in some embodiments, the composition is free of talc or contains up to 5, 4, 3, 2, or 1 percent by weight talc, based on the total weight of the composition. In some embodiments, the composition contains less than 5 percent by weight talc, based on the total weight of the composition. In another example, the composition according to the present disclosure is free of or comprises less than one percent by weight of n?ontmoriHon.ite-_: cla having a chip thickness of less than 25 nanometers. Irs. another example, th composition according to the present disclosure is free of or comprises or comprises less than one percent by weight of calci um carbonate having a mean particle size of less than 100 nanometers.

Other additives may be incorporated into the composition disclosed herein in any of the embodiments described above. Examples of other additives that may be useful, depending on the intended use of the composition, include preservatives, mixing agents, colorants, dispersanis, floating or anti-setting agents, flow or processing agents, wetting agents, anti-ozonant, and odor scavenge s. Any of the compositions, masterbatch compositions, or the let-dow compositions described herein can include one or more of such additives. Compositions according to the present disclosure are stsitabie for injection molding.

Elevated temperatures (e.g., in a range from 100 ^*C to 225 ^°C) may be useful for mixing the components of the composition in an extruder. Hollow glass microspheres may he added to the composition after the polyolefin, compatilizsr, and impact modifier are combined. The method of i njection molding the composition disclosed herein can utilize any type of injection molding equi ent, generally including a material hopper (e.g., barrel), a plunger (e.g., injection ram or screw-type), and a heating unit

The composition and method according to the present disclosure are useful for making low density products (e.g., having a density in a range from 0.75 to 0.95, 0.78 to 0.9, or 0.8 to 0.9 grams per cubic centimeter) with good tensile strength, flexural strength, and impact resistance, which are useful properties for a variety of applications. Articles thai can be made by injecting molding the compositions according to the present disclosure include hardhats and interior and exterior automobile component (e.g., hoods, trunks, bumpers, grilles, side claddings, rocker panels, fenders, tail-gates, in wire and cable applications, instrument panels, consoles, interior trim, door panels, heater housings, batter ' supports, headlight housings, front ends, ventilator wheels, reservoirs, and soft. pads).

In many^•embodiments, as shown in the Examples, below, at least one of the impact strength, tensile strength, or^'flexnrsl strength of the compositions according to the present disclosure approach or in some cases ^'even surprisingly exceed the impact strength of the polyolefin without the addition of hollow glass microspheres.

In a first embodiment, the present disclosure provides a composition comprising:

a polyolefin comprising first repeating units;

hollow glass microspheres;

& polyolefin impact modifier that is chemically non-erossiinked and free of polar functional groups; and

a compati.bliz.er comprising the first repeating units and second repeating units, which are the first repeating units modified with polar functional groups,

wherein the hollow glass microspheres are present in a range from 40% to 70% by volume, the polyolefin impact modifier is present in a range from 20% to 50% by volume, and the compatibilizer is present in a range from 4% to 12% by volume, based on the total volume of the hollow glass microspheres, the polyolefin impact modifier, and the compatibilizer. The composition may also have any of the following features, alone or in combination: the composition comprises greater at least ten percent by weight of the glass, based on the total weight of the composition;

the polyolei In is other than a polypropylene homopolymer;

the composition has a melt flow index at 1 0 ^:'C and 2.16 kilograms of at least _.3 grams per 10 minutes;

the composition has a notched izod impact strength of at least 60 jouies meter;

the poiyolefm comprises polyethylene, and the eompatibiiizer comprises ethylene repeating units;

the first repeating units are polypropylene repeating units, and the compatibilizer comprises propylene repeating units, and the poiyolefm is a copolymer comprising at least 80% by weight propylene unit or the poiyolefm is a medium or high impact polypropylene..

In an alternate first embodiment,, the present disclosure provides a masterbatch composition for combining with a poiyolefm comprising first repeating units, wherein, the masterbatch comprises:

hollow glass microspheres;

a polyolefln impact modifier that is- chemically non-cross! inked and free of polar functional groups; arid

a compatiblizer ^'comprising the first repeating units and second repeating units, which are the first repeating units modified with polar-functional groups,

wherein the hollow glass microspheres^' are present in a range from 40% to 65% by volume, the poiyo!efm impact modifier is present in. a range from 20% to 50% by volume, and the compatibilizer is present in a range from 4% to 15%: by volume, based on tbe total volume of the hollow glass microspheres, the poiyolefm impact modifier, and the compatibilizer.

in a second. embodiment, the present disclosure provides the composition of the first embodiment, wherein the- oiyolefm comprises at least one of pol ethylene or polypropylene. in a third embodiment, the present disclosure provides the composition of the first or second embodiment, wherein the first repeating units are. polyethylene repeating units.

In a fourth embodiment, .the present disclosure provides the composition of any -one of the- first to third embodiments, wherein the poiyolefin impact modifier has a melt, flow index at 190 "C and 2.16 kilograms of at least 10 grams per 10 minutes.

In a fifth embodiment, the present disclosure provides the composition of any one of the first to fourth embodiments, comprising greater than ten percent by weight of the hollow glass microspheres, based on the total weight of the composition. In a sixth embodiment, the present disclosure provides the composition of any one of the first to fifth embodiments, comprising greater than two percent by weight of the compatibslizer, based on the total weight of the composition,

in a seventh em diment, the present disclosure prov ides the composition of any one of the first to sixth embodiments, comprising greater than three percent by weight of the

compatibilizer, based on the total weight of the composition.

In. an eighth embodiment, the present disclosure provides the composition of any one of the- first to seventh embodiments, wherein the eompatibiiizer is a mafeic anhydride-modified polyolefin.

In a ninth embodiment the present disclosure provides the composition of any one of the first to eighth embodiments_* further comprising reinforcing fillers.

In a tenth embodiment the present disclosure- provides the composition any one of the first to ninth embodiments, wherein the composition comprises less than five percent by weight talc, based on the total weight of the composition.

In an eleventh embodiment, the present disclosure provides the composition of any one of the first to tenth embodiments, wherein the composition comprises les (has -one percent by weight of at least one of montmorillonite clay having a chip thickness of less than 25 nanometers or calcium carbonate having a mean particle size of iess than I GO nanometers.

In a twelfth embodiment,, the present disclosure provides the composition of any one of the first to eleventh embodiments, wherein the hollow glass microspheres are not treated with a silane coupling agent,

ϊη a thirteenth embodiment, the present disclosure provides the composition of any one of the first to twelfth embodiments, wherein a hydrostatic pressure at which ten percent by volume of .the hollow _.glass microspheres collapses is at least about 50 megapasca!s.

In a fourteenth embodiment,, the. present disclosure provides the composition of any one. of the first to thirteenth embodiments, wherein the poiyolefm impact modifier is an ethylene

propylene elastomer, an ethylene octcne elastomer, an ethylene propylene diene elastomer, an ethylene propylene octene elastomer, or a combination thereof.

In a fifteenth embodiment, the present disclosure provides the composition of any one of the first to fburteenih embodiments, wherein the polyolefin impact modifier is an ethylene octene elastomer.,

in a sixteenth embodiment, the present disclosure provides an article comprising a solidified composition of any one of the first to fifteenth embodiments.

in a seventeenth embodiment, the present disclosure provides the article of the sixteenth embodiment, wherein the article is a hardhat. In an eighteenth embodiment, the. present^' disclosure provides the article of the sixteenth embodiment, wherein the article is an -interior or exterior automobile component.

In a nineteenth embodiment, the present disclosure provides a method of making an article, the method comprising injection molding the composition of any one of the first to fifteenth embodiments to make the article.

In a twentieth embodiment, the present disclosure provides the method of the nineteenth embodiment, wherein- the article Is a hardhat.

In a twenty-first embodiment, the present disclosure provides the method of the nineteenth embodiment, wherein the article is an interior or exterior automobile component

The following specific, but non-limiting, examples will serve to illustrate the invention, in these examples, all amounts are expressed in parts per hundred resin (phr) unless specified otherwise. In these examples, /M means "not measured",

EXAMPLES

MATERIALS

Tabic 1

Abbreviation Material Description

35.00g/ I0 min (230°C/2J 6 kg)

Commercially available from Pinnacle Polymers, Garyville, LA, under the trade

PP7 designation "Pinnacle PP 4150H". High impact PP copolymer. Melt Flow rate

55<0Og/10 min (230°C 2.16 kg)

Commercially available from LyondellBaseli, Houston, Ϊ.Χ, under the trade designation " Hi fax CA 387 A", it is a reactor TPO (thermopfasiie polyo!efin)

PP8

manufactured using LyondellBasei s Catalloy process technology. Melt flow rate (MFi) 18.00 g/10 min (230°C/2.16kg)

Malek anhydride modified homopolymer polypropylene under the trade name POLYBOND® 3200 available from Adds v ant.

CI

Melt-flow rate (1 0C 2.16 kg) I 15g/i0min.

0,8-1.2 % Male anhydride content.

Ma!eic^■anhydride modified high density polyethylene under the trade name

C2 POLYBOND® 3009 available from Addivan

Melt flow rate (190C/2.16 kg) 3-6 g/ Omin.

0.8-1.2 % Maieic anhydride content,

An^' anhydride modified polyethylene -commercially available from E. 1. du Pont de

C3 Nemours and Company (Wilmington, DE) under the trade designation Fusabond®

E226.

Polyolefin elastomer (ethylene octene copolymer) with a nominal loose talc coating,

1 1

commercially available under the trade designation Engage® 840? with a melt flow rate (190C/2.16kg) 30_.g 1 .mm from Dow Chemical Company (Midland, Ml)

Polvolefln elastomer (ethylene octene copolymer) with a nominal loose talc coating,

IM2

commercially available under the trade designation Engage® 8137 with a melt flow rate (5 0C/2.I6kg) 13 g/!Omio from Dow Chemical Company (Midland. MI)

Polyolefm elastomer (ethylene octene copolymer) commercially available under the

ΪΜ3

trade designation Engage® 8100 with a melt flow rate (190C/2.16kg) 1 g/l 0mm from Dow Chemical Company (Midland,. M!)

Commercially available from LyondellBaseli, ^'Houston, TX,_: under the trade

1M4 designation " Hifax CA 138 A^M. It is a reactor TPO^' (thermoplastic poiyolefm) manufactured using LyondellBaseli' s Catalloy process technology. Melt flow- rate (ΜΡΪ) 2.8 g 10 min (230°C/2.16kg) Abbreviation Materia! Descri tion

3M™ IM1.6K Mi-Strength Glass Bubbles with 16,000 psi crush strength, 20 micron average diameier and 0.46 g/cc true density commercially available from 3M

GB 1

Company, St Paul, M under the trade designation "3M ΪΜ1 Κ Hi-Strength Glass Bubbles"

Hollow glass microspheres commercially available from Sinosteel Maanshao Inst of Mining Research Co. ltd. under the trade designation "Y8000" (8600 psi crush strength at 80% survival and 0.6 g cc true density as measured by 3M using ASTM Test Method D3102 -78 (1982); "DETERMINATION OF ISOSTATIC COLLAPSE

GB2 STRENGTH OF HOLLOW GLASS MICROSPHERES" with exceptions. The sample size of hollow microspheres was 1 true cc. The hollow microspheres were dispersed in glycerol (20.6 g), and data reduction was automated using computer software. The 80 % crush strength value reported herein is the Jsostatic pressure at wh i ch 20 percent by volume of the glass micrd ubb!es- collapse. )

A high-density polyethylene (hard hat grade) for injection molding with melt flow

HOPE

rate (.I90G 2.16kg) 5 g/lOrnin, commercially available from BRAS EM S.A. (Sao_: Paolo, Brazil) under the trade designatioiv'iE59U3^!5

Test Methods

gcnsitv

.Density of the molded parts was determined using the following procedure. First, the- molded parts were exposed to high temperature ^"m a oven (Maber ierm > ^"N 300/14) in order to volatilize me polymer resin. The oven was set with a temperature ramp profile to run from 200°C •to 550 °G in 5 hours. After the temperature reached 550 °C, it was kept constant for 12 hours.

Weight percent of glass bubbles was calculated from the known amounts of molded part before and after the burn process using the following equation:

Weight % of Glass Bubbles = (Weight of Residual Inorganics After Bum) / (Weight of Molded Material Before Bum) xIOO

We then determine the density of the glass bubble residue (doe) using a helium gas pycnometer (AccuPcy 1330 from Microrneritics). Finally, the molded part density is calculated from the known weight percent of glass bubble residue (W% GB), weight percent of polymer phase (1- w%G.8)_s the density of glass bubble residue (dm) and the known, polymer density (d pojymer) from supplier datasheet,

Mechanical Properties

Mechanical properties of the injection-molded composites were measured using ASTM standard test methods listed in Table 2, An MTS frame with a 5k ad cell and tensile and 3 point beading grips were used for tensile and flexaral properties, respectively, fo tensile testing mode, the test procedure described in ASTM D~638- i 0 standard was followed, however no strain gauge was used, and instead, grip separation distance was used to determine the sample elongation. Tinius 01 sen model 1X503- impact tester and its specimen notcher were used to measure r om temperature Notched teod impact strength of the molded parts. A Tinius Oisen MP2CX5 extrusion plastometer was used for melt flow index testing on samples. At. least 5 different specimens from a given sample were tested in ail tensile, flexural and impact tests. Arithmetic average of the results were determined and reported in the following examples. The results were observed to be highly repeatable and the standard deviation in test results was -observed to be in the range of 3-5% or lower. At least two different specimens were tested in melt How inde tests. The melt flow tests were observed, to b highly repeatable with almost identical experimental results. Arithmetic average of the results ^'were determined and reported in the following examples.

Table 2 Property Test Methods

Melt Flow Index MFI D-1238- 13

Samples were compounded in a co-rotating mtermeshmg 1 inch twin screw extntde-r (L/D: 25) equipped with 7 heating zones. Polymer pellets (polypropylene or HOPE}, the impact modifier and compatibilizers were dry blended and fed In zone 1 via a resin feeder and then passed through a set of kneading blocks and conveying elements. The extrudate was cooled in a water bath and pelletized. The pelletized blend was then reintroduced through the resin feed hopper and passed, through the kneading block section again to ensure its complete melting before glass bubbles were side .fed downstream in zone 4. At the point of glass bubble side feeding as well as for the rest of the downstream processing, high channel depth conveying elements (OO/ID: ! .75) were used.

For polypropylene, the temperature in zone I was set to ! S0°C and all other zones to 22 °C. For HOPE, zone 3 was set to I S0°C and all others were set to 215 °C respectively. The screw rotation speed was set to 250 rpm in both cases. The extrudat© was cooled in a water bath and pelletized.

.fojertiqa j oMinK Procedure

All samples were molded using a BOY22D injection molding machine with a 28mm general purpose barrel and screw manufactured by Boy Machines inc.. Exton, PA, A standard ASTM mold with cavities for tensile, flex and impact bar was used for all molded parts. The injection molded specimens were kept on a lab bench at room temperature and under ambient conditions for at least 36 hours before performing any testing.

Comparative Examples IA-lG a¾ l Example I

High Density Polyethylene .Based Formuiatiosss

The addition of 12 wt% GB (0.46g cc) to HOPE reduces density by about 10% (compare CEIA and CEIB) but the reduction in density comes at the expense of 65% decrease in notched impact: strength. The tensile^' strength also is reduced because there is less resin to withstand the applied forces causing yielding at lower stress levels. The benefits, on the other hand, are increased ^'Stiffness as. evidenced by increased level of tensile and flex modulus.

in order to compensate for the decreased impac strength, a low viscosity Impact modifier 1 (MB 30 g 10 in @! 90C/2,I 6kg} is added in CE1 C. The addition of this impact modifier increases notched impact strength from 32 J/^'m to 37 i/m, which is still well below that of unfilled HOPE (91 J/ra). The increase in impact strength comes at the expense of decreased tensile strength (from 23,3 MPa to 1 MPa due to glass bubbles and further to 14.2 MPa due^' to the addition of the impact modifier) and i!exural strength (from 24.9 to 20.0 MPa),

When a functional corapatibilizer based on polyethylene such as C2 is used along with the impact modifier, the notched impact strength further increases remarkably from 37 J/m to 120 j/ra while also increasing tensile and flexural strength (CEiC and EX.! ). Table 3 ROPE Baaed Formulas

Effect of im act Modifier Viscosity asad Blends in HDPE

Examples 2-4 in Table 3 show that, the use of a higher MFI Impact modifier such as iMl (MFI=30) in E l results In a higher composite final MFI whereas a lower MFi impact modifier such as ΪΜ3 (MFI-i) m EX2 results in a lower composite final MFI, The use of higher MFI impact modifiers in E i and EX3 do not affect adversely the final MFI of the composite while the lower MFI impact modifier in EX2 may adversely affect the final composite M i. EX4 shows t a one can blend a high and low MFI impact modifier for an optimized viscosity. Hence, this invention also includes those impact modifiers which are blends of high and low MFI i mpact modifiers.

Correct Sek^sc i s of Compsii lsaer

Table 4 demonstrates that the correct selection of€2 for HDPE (EX3) improves the impact strength vs. selecting CI for HOPE (CEI B), The eompatibUizer is chosen such thai the back bone where- the functional grafts are attached ca co-crystallize and compatible with the main matrix resin.

Table 4 HOPE Based Formulas

Eaampie 5 and Comparative Examples 2A-2C

Low Impact Polypropylene Hotnopolymer Based Formulations

As seen in Table 4, similar to that seen with HOPE, the addition of glass bubbles to polypropylene homopolymer reduces density by about 9.3 % (compare CE2A and CB2B) but the reduction in density comes at the expense of aboot a 50% decrease in notched impact strength.

In order to compensate for the decreased impact strength, a low viscosity impact modifier impact modifier I (MFI 30 g/lOmin @1 0C/2,1 kg) is added in CE2C. The addition of this impact modifier increases the notched impact strength 87% from 24.7 to 46.3 J/m. The increase in impact strength comes at the expen se of decreased tensile strength (from 29.2 MPa to Ϊ 9.3 MPa due to glass bubbles and further down to 13.9 MPa due to the addition of the. impact modifier) and -fiexural strength (from 37.6 to 23.8 MPa).

When a functional compatibtlfcser based on polypropylene (C I) is used along with the impact modifier, the notched impact strength further is further increased from 46.3 J^'/ra to 60 J/m while also increasing tensile and fiexural strength (compare- 3 and 4).

Table 5 Low Impact Polypropylene Hosnopolymer Based Formulations.

Exam l s 6-8

Effect of Impact Modifier Viscosity and Blends in Low Impact Polypropylene

As seen in Table 5 tine ase of a higher MFI impact modifier such as !Mi (MFI=30) in E 5 results in a final composite MFI of 5.5 whereas a lower MFI impact modifier such as IM3 (EX7) results in a final composite MFI of 2.9.

The use of higher MFI impact modifiers EX5 and BX6 3 do not affect adversely the final MFI of the composite. BX8 shows that one -can blend a high and low MFI impact modifier for an ορΐΐ^ηι ί zed. v 1 scosity .

Table 6 Low Im act Polypropylene Hotnopoiymer Based Formulations

Exa ple 9 and Comparative Examples 3 A-3C

Medium impact Polypropylene Copolymer Based Formulations

In example 9, we demonstrate that me same effect is observed in a medium impact polypropylene as in a low impact polypropylene (increasing impact strength while increasing tensile and flex strength.

The addition of glass bubbles reduces density by about 9.3 % (compare CB3A and CE3B) but the reduction in density comes at the expense of about a 55% decrease in notched impact strength.

In order to compensate for the decreased impact strength., a low viscosity impact modifier IM ! (MFR 30 g/iOmin @1 0^*C/2.16kg) is added in CE3C. The addition of this impact modifier increases the notched impact strengt 146% from 37,6 to 92.7 J/m. The increase in impact strength comes at the expense of decreased tensile strength (from 26.6 MPa to 16.5 MPa-due to glass bubbles and further down to 12.7 MPa due to the addition of the impact modifier) and^' flexural strength (from 34.6 to 29.3 MPa).

When a functional compatibiJizcr is used along with the impact modifier, the notched impact strength further is further increased from 92.7 J/m to 122 j/m while also increasing tensile and f!exural strength (compare formula C.E3C and Ex9).

Table 7 Mcdiam Impact Pol propylene Copolymer Based Formulations

Example 1.0 agd Comparative Examples CE4A-4C

Hi h Impact Polypropylene Co ol mer Based Fermuiatio&s

Several automobile plastics use high impact po!ypropylenes (especially in exteriors) and weight reduction with glass bubbles has had a harder time penetrating into parts that require high impact. In example 10, we demonstrate thai this invention is also applicable in high impact polymer and could help meet specifications that require high impact. Note thai we are using 14 wt¾ GBI alone and that reinforcing fillers such as talc and glass fibers can easily be added to reinforce these current formulas and increase modulus and strength further.

in high impact polypropylene, the notched impact strength reduction is significant at 87% from 545 J m to 65 J/m. We are significantly recovering impact strength up to 215 J/m with no detriment on density. In example 10, we demonstrate thai the combined low viscosity non- functionsli ed impact modifier and functional compatibilizer also shows the same improvement of increasing impact strength while increasing tensile and flex strength.

Ta e 8 High Impact Polypropylene Copolymer ^'Based Formulations

Exam le 11 &Ϊ ! Comi?ar¾ijY¾ Exa ples SA-Si)

^'Effect of Impact Modifier Viscosity and Blends m High Impact Folypropyleoe

Table 9 High Im ct Polypropylene Homopoymer Based Formulations

Compaii iiizer ssly

Usin compati ilizer alone wkhoat im c modifier

Table 10, the presence of compatabilizers does not significantly change notched impact strength significantly neither in low. medium, or high impact polymers. Table 10 Effect of using Cosss at Iker only without the Impact Modifier

Cor ®& rat ve Examples 7. -7F and E am pl¾ 12

Correct Seleetl ss of CoMpstsMIizers

Table i J demonstrates that the correct selection of C I for PP I (EX 12) improves the impact strength vs. selecting C2 For FPl (CE7E). The compatibilizer is chosen^' such that the back bone where the functional grafts are attached can co-crystallize and compatible with the main matrix resin. Table 11

>

EXAMPLE 13 and Comparative Examples 8A-8C

Alternate Glass Babbie

Table 12 Fonnalations were similar to those in Table 3 except that an alternate glass bubble was used. As Table 12 demonstrates the impact strength of the composite is again improved with the combination of the impact modifi er and correct compatibiHzer (EX13).

Table 12

EXAMPLES 14, 15, Ifraad Con»p¾»rtiv¾ .Erampfea 9A~9€ Table 13

1XA FLES 17, 18, 19 ^Comparative xamples lQA^QC. Table 14

EXAMPLES 20, 21, 22 aasi Comparative E amgks IIA-UC TabfelS

jXAMPLES ^ 24, 25 and Comparative Examples 12Α,1,2,ς able 36

EXAMPLES 26, 27, 28 and Comparative wm?\*s 13A-13C

Table 17

EXAMPLE 29 and Comparative Examples 13A, I3B, 14A Tsble 18

E am l 30 and Comparative Examples I3A , 13B and ISA

Correct Selection of Compaii slizers

Table 1 demonstrates that the correct selection of CI for PP7 (EX30) improves the impact strength vs. selecting C2 for FP7(€E! 5A). The compatsbiHzer is chosen such that the back bone where the functional grafts are attached can co-crystallize asid compatible with the main matrix resin. Table 19

Example 31, 32 t Com arative Examples 13A , 13¾ and 1 S

Preferred Amount of Co spatib zes-s

Table 20 demonstrates that the preferred amount of eompatibilixer for PP7 (EX3Q asid EX3 1 ) shows improved impact strength whereas lower amounts (CEISA) lower the impact strength compared to unfilled control resin CB13A and impact -modifier contamkg.with 0% eonipatibilizers only (CE12C) shown above. Preferred amount is between 2 and 4 %. Table 20

Preferred Amount of Impact Modifier Table 21

Coa.parat¾n, £ynnpIes CE2A, CE17A, CE.17B, CE17C, CE17D, CE2C and EXS Effect of eompaiibslizer In the absence of glass hubbies

Comparing CEI 7A to CE17B, one can see that the addition of compatihiiizer to a compound with 20% poiy olefin elastomer does not result in further enhancement of the impact strength. In fact there is a slight reduction of impact strength.

Comparison of CE! 7 A to CE1 B also shows that compatibilizer have a neutral to negligible improvement (4% increase) effect on the impact strength of a compound that contains 15.5 wt% impact modifier.

These results are contrary to what we see with glass bubble containing formulas where the correct selection of compatibilizer type and amount improve the impact strength of a compound containing po!yo!eftn elastomer (compare C.E2C and EXS with 30% increase in impact strength).

This disclosure is not limited to the above-described embodiments but is to be controlled by the limitations set forth in the following claims and any equivalents thereof. This disclosure may be suitably practiced in the absence of assy element .not specifically disclosed herein.

Claims

What is claimed is:

1. A composition comprising:

a polyolefin comprising first repeating units;

hollow glass microspheres;

a polyolefin im act modifier that is chemically non-crossiinked and free of polar functional groups; and

a compatibiizer comprising the first repeating units and second repeating units, which are the first repeating modified with polar functional groups,

wherein the hollow gl ss microspheres are present in a rang® from 40% to 70% by volume, the polyolefin impact modifier is present in a range from 20% to 50% by volume, and t e

corapatibi!izer is present in & range from 4% to 12% by vol ume, based on the total volume of the hollow glass microspheres, the polyolefin impact modifier, and the^' compatibilizer, and wherein the composition has a notched Ίζού impact strength of at least 60 joules/meter, and wherein the composition comprises greater than ten percent by weight of the gl ass, based on the total weight of the composition.

2. The composition of claim 1, wherein at least one of the following conditions is me the tensile modulus of the composition is at least 50% of the polyolefin, or the tensile strength of the composition is at least 50% of the polyolefin, or the ftexural modulus of the composition, is at least 50% of the polyolefin, or the flexurai strength of the composition is at least 50% of the polyolefin.

3. A ma^'sterbateh composition for combining with a po!yofefm comprising first repeating units, wherein the masterbatch comprises;

hollow glass microspheres;

a polyolefin impact modifier that is chemically noa-crossHnfced and free of polar functional groups: and

a compatibiizer comprising the first repeating units and second repeating units modified with polar functional groups,

wherein the hollow glass microspheres are present in a range from 40% to 65% by volume, the polyoiefra impact modifier is present in a range from 20% to 50% by volume, and the

compatihiiizer is present in a rang© from 4% to 15% by volume, based on the total volume of the hollow glass microspheres, the polyolefin impact modifier, and the compatibiiizer.

4. The composition of any one of claims 1 to 3, wherein the polyolefin comprises at least one of polyethylene or polypropylene,

5. The composition of an one of clai s ! to 4. wherein the first repeating units are polyethylene repeating units.

6. The composition of any one of claims 1 to 5. wherein the polyokfm impact modifier has a melt flow index at 190 ^*€ and 2.16 kilograms of at least 10 grams per 10 minutes.

7. The composition of any one of claims 1 to 6, comprising greater than two percen by weight of the compatihilizer, based on the total weight of the composition.

8. The composition of any one of claims 1 to 7, wherein the compatibiUzer is a makic

anhydride-modified po!yoiefin.

9. The composition of any one of claims 1 to 8, further comprising reinforcing fillers.

10. The composition of any one of claims 1 to 9, wherein the composition comprises less than five percent by weight talc, based on the total weight of the composition, or wherein the composition comprises- less than one percent by weight of at least one of montmorillo te clay -having a chip thickness of less than 25 nanometers or calcium carbonate having a mean particle size of less than 100 nanometers.

1 1. The composition of any one of claims 1 to 10, wherein the hollow glass microspheres are not treated with a sifaae coupling agent.-.

12. The composition of any one of claims 1 to 1 1 , wherein a hydrostatic pressure at which t n percent by volume of the hollow glass microspheres collapses is at least -about 50 megapase&!s.

13. The composition of any one of claims 1 to 12, wherein the poly olefin impact modifier is art ethylene propylene- elastomer, an ethylene ociene^' elastomer, an ethylene propylene diene elastomer, an ethylene propylene octene elastomer, or a combination thereof,

14. An article comprising the composition of any one of claims 1 and 3 to 13 except as dependent on claim 2, wherein the composition is a solid, wherein the article is a hardhat, or wherein the article is an interior or exterior automobile component.

15. A method of making an article, the method comprising injection molding the composition of any one of claims 1 to 13 to make the articl e.