EFFECT FOR COSMETIC PACKAGING

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 1 19 to U.S.

Provisional Application No. 62/21 1 ,061 , filed on August 28, 2015, which ^' incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to the field of antistatic multilayer films and in particular to articles, such as bottles or recipients, made with antistatic multilayer films.

BACKGROUND OF THE INVENTION

Generally, a fabricated article made from a polymeric material can become statically charged, and the surface can attract and hold charged particles such as dust in the air. In some cases an article can become damaged and/or otherwise devalued by the adhesion of electrostatically charged species.

Accordingly, antistatic properties may be important for many applications for preventing adhesion of charged particles. Except for polymers of inherently high polarity, most organic polymeric materials lack adequate antistatic resistance especially at low humidity. This is especially true for polyolefin materials, such as polypropylene, polyethylene, and ethylene copolymers, and in particular for ionomers.

An ionomer such as Surlyn® which is readily available

commercially from E. I. du Pont de Nemours and Company, Wilmington, Delaware, USA (DuPont), has been used in packaging applications for many years for its heat seal properties, transparency, scratch resistance and toughness. It is used in cosmetics packaging for aesthetics such as perfume caps, bottles, or cases. An ionomer is also used to replace PVC in flooring.

lonomers are generally produced by neutralization of ethylene acid copolymers with zinc or sodium metal ions. Such ionomers may have a tendency to pick-up a static charge, more so than alternative materials such as polyethylene. The static charge attracts dust, negatively affecting the appearance of cosmetics packaging. Dust accumulation can detract from the appearance of the packages. It is therefore a need to reduce the tendency of an ionomer to attract dust.

Many attempts have been made to address this issue from aspects of performance, cost, and ease of conversion to final products. Antistatic agents can be incorporated into the composition of a molded article or an antistatic agent can be applied to the surface of an article as a way of preventing build-up of static charge on an article. Use of antistatic agents is not trouble-free.

Migrating antistatic agents may be used in ionomer to reduce the static effect. However high amounts of migrating antistatic agents are needed and this is detrimental to the properties of the ionomer such as glossiness, scratch resistance and adhesion of decorative objects such as printing ink, labels and similar. Potassium based ionomers have also been used in order to achieve antistatic properties but these approaches lead to poor surface appearance of the ionomer as well as reduced stiffness and scratch resistance.

Therefore, there is still a need for articles comprising an ionomer at the surface that would provide for surface appearance properties such as transparency, glossiness and scratch resistance while improving the ionomer tendency to attract dust, in particular improving the ionomer antistatic properties. SUMMARY OF THE INVENTION

Described herein is an antistatic multilayer film having a) a first layer comprising an ionomer resin, b) a second layer comprising an antistatic additive blended with an ionomer resin or an ethylene acid copolymer resin, wherein the antistatic additive is a permanent antistatic additive selected from the group consisting of polyetheresteramides, and c) a third layer comprising a polyolefin resin.

In one embodiment, the antistatic additive is present in the second layer in an amount of between 20 to 50 % by weight based on the total weight of the second layer. In another embodiment, the ionomer resins in the first and second layers are the same. Preferably, the antistatic additive is a polymeric system based on polyamide/polyether block amides. Preferably, the ionomer resin is a copolymer or ethylene and between 10 and 23 weight percent of methacrylic acid neutralized with between 0.5 and 99 % of metal ions selected from Zn or Na. Preferably, the ethylene acid copolymer resin is a copolymer of ethylene with 1 to 23 weight percent of methacrylic acid. In a preferred embodiment, the polyolefin resin is a polyethylene resin.

Also disclosed herein is a method for making the multilayer film according to the invention. The method includes the steps of a) providing a first ionomer resin, b) providing a second ionomer resin or an ethylene acid copolymer resin blended with a permanent antistatic additive selected from the group consisting of polyetheresteramides, c) providing a polyolefin resin, d) optionally providing a polyester resin, e) coextruding the resins of steps a) to d) in the form of a film. Preferably, the

coextrusion of step (e) is made by blow moulding.

Also disclosed herein are articles comprising the multilayer film according to the invention. In particular, the article of the invention may be a bottle, a recipient, a floor top layer or any other protective surface layer film.

Also described herein is the use of the multilayer film according to the invention as a decorative scratch resistant antistatic film, and the use of the multilayer film according to the invention as an antistatic film.

DETAILED DESCRIPTION

Definitions As used herein, the term "a" refers to one as well as to at least one and is not an article that necessarily limits its referent noun to the singular.

As used herein, the terms "about" and "at or about" are intended to mean that the amount or value in question may be the value designated or some other value about the same. The phrase is intended to convey that similar values promote equivalent results or effects according to the invention.

As used herein, the term "acrylate" means an ester of acrylic acid with an alkyl group. Preferred in the invention are acrylates with alkyl groups having 1 to 4 carbon atoms.

As used herein, the term, "(meth)acrylic acid" refers to methacrylic acid and/or acrylic acid, inclusively. Likewise, the term "(meth)acrylate" means methacrylate and/or acrylate and "poly(meth)acrylate" means polymers derived from the polymerization of either or a mixture of both corresponding type of monomers.

As used herein, the term "terpolymer" means that the copolymer has at least three different comonomers.

As used herein, the term "copolymer" refers to polymers comprising copolymerized units resulting from copolymerization of two or more comonomers. In this connection, a copolymer may be described herein with reference to its constituent comonomers or to the amounts of its constituent comonomers, for example "a copolymer comprising ethylene and 18 weight percent of acrylic acid", or a similar description. Such a description may be considered informal in that it does not refer to the comonomers as copolymerized units; in that it does not include a conventional nomenclature for the copolymer, for example International Union of Pure and Applied Chemistry (lUPAC) nomenclature; in that it does not use product-by-process terminology; or for another reason. As used herein, however, a description of a copolymer with reference to its constituent comonomers or to the amounts of its constituent comonomers means that the copolymer contains copolymerized units (in the specified amounts when specified) of the specified comonomers. It follows as a corollary that a copolymer is not the product of a reaction mixture containing given comonomers in given amounts, unless expressly stated in limited circumstances to be such. The term "copolymer" may refer to polymers that consist essentially of copolymerized units of two different monomers (a dipolymer), or that consist essentially of more than two different monomers (a terpolymer consisting essentially of three different comonomers, a tetrapolymer consisting essentially of four different comonomers, etc.).

The term "acid copolymer" refers to a polymer comprising copolymerized units of an a-olefin, an α,β-ethylenically unsaturated carboxylic acid, and optionally other suitable comonomer(s), such as an α,β-ethylenically unsaturated carboxylic acid ester.

The term "ionomer" refers to a polymer that is produced by partially or fully neutralizing an acid copolymer as described above.

The antistatic multilayer film described herein includes a) a first layer comprising an ionomer resin, b) a second layer comprising an antistatic additive blended with an ionomer resin or an ethylene acid copolymer resin, wherein the antistatic additive is a permanent antistatic additive selected from the group consisting of polyetheresteramides, and c) a third layer comprising a polyolefin resin.

The ionomer of the present invention is a polymer that is produced by partially or fully neutralizing an acid copolymer, such as ethylene acid copolymers, as described below.

Suitable ethylene acid copolymers and ionomers are described in U.S. Patent No. 7,641 ,965, issued to Bennison et al., and in particular to U.S. Patent No. 3,264,272 to Rees.

Briefly, however, the ethylene acid copolymer comprises

copolymerized units of an a-olefin having from 2 to 10 carbon atoms and about 8 to about 30 weight percent, preferably about 15 to about 30 weight percent, more preferably about 15 to about 25 weight percent, yet more preferably about 15 to about 23 weight percent, or still more preferably about 18 to about 20 weight percent of copolymerized units of an α,β- ethylenically unsaturated carboxylic acid having 3 to 8 carbon atoms. The weight percentage is based on the total weight of the ethylene acid copolymer. Preferably, the α-olefin comprises ethylene; more preferably, the α-olefin consists essentially of ethylene. Also preferably, the α,β- ethylenically unsaturated carboxylic acid comprises acrylic acid, methacrylic acid, or a combination of acrylic acid and methacrylic acid. More preferably, the α,β-ethylenically unsaturated carboxylic acid consists essentially of acrylic acid, methacrylic acid, or a combination of acrylic acid and methacrylic acid.

The ethylene acid copolymers may further comprise copolymerized units of other comonomer(s), such as unsaturated carboxylic acids having 2 to 10, or preferably 3 to 8 carbon atoms or derivatives thereof. Suitable acid derivatives include acid anhydrides, amides, and esters. Esters are preferred derivatives. Preferably the esters are α,β-ethylenically unsaturated carboxylic acid ester comonomers and include, but are not limited to, methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate and combinations thereof.

The ethylene acid copolymers may be synthesized by any suitable polymerization process. For example, the ethylene acid copolymers may be polymerized as described in U.S. Patent Nos. 3,404, 134; 5,028,674; 6,500,888; and 6,518,365.

Preferably, the ethylene acid copolymer has a melt index (Ml) of about 60 g/10 min or less, more preferably about 45 g/10 min or less, yet more preferably about 30 g/10 min or less, or yet more preferably about 25 g/10 min or less, or still more preferably about 10 g/10 min or less, as measured by ASTM method D1238 at 190°C and 2.16 kg.

Some suitable ethylene acid copolymer resins are commercially available from E.I. du Pont de Nemours and Company of Wilmington, DE ("DuPont"), under the trademark Nucrel®.

To obtain the ionomers, at least a portion of the carboxylic acid moieties of the ethylene acid copolymers is neutralized to form carboxylate groups. Preferably about 5 to about 90 %, more preferably about 10 to about 50 %, yet more preferably about 20 to about 50 %, or still more preferably about 20 to about 35 % of the carboxylic acid groups are neutralized, based on the total carboxylic acid content of the ethylene acid copolymers. An example of a suitable procedure for neutralizing the ethylene acid copolymers is also described in U.S. Patent No. 3,404, 134.

The ionomers comprise cations as counterions to the carboxylate anions. Suitable cations include any positively charged species that is stable under the conditions in which the ionomer composition is

synthesized, processed and used. Preferably, the cations are metal cations that may be monovalent, divalent, trivalent or multivalent.

Combinations of two or more cations that may have different valencies, for example mixtures of Na+ and Zn2+ or mixtures of NH4+ and K+, are also suitable. The cations are more preferably monovalent or divalent metal ions. Still more preferably, the metal ions are selected from the group consisting of ions of sodium, lithium, magnesium, zinc, and potassium and combinations of two or more thereof. Still more preferably, the metal ions are selected from the group consisting of ions of sodium, ions of zinc and combinations thereof. Still more preferably, the metal ions comprise or consist essentially of sodium ions.

The ionomer preferably has a Ml of about 13 g/10 min or less, more preferably about 5 g/10 min or less, or still more preferably about 3 g/10 min or less, about 1 .0 g/10 min , as measured by ASTM method D1238 at 190°C and 2.16 kg. The ionomer also preferably has a flexural modulus greater than about 40,000 psi (276 MPa), more preferably greater than about 50,000 psi (345 MPa), or still more preferably greater than about 60,000 psi (414 MPa), as measured by ASTM method D790 (Procedure A).

Some suitable ionomeric resins are commercially available from DuPont, under the trademarks Surlyn® resins.

The antistatic additive of the present invention is a permanent antistatic additive selected from the group consisting of

polyetheresteramides. The polyetheresteramides of the present invention are known in the art and are for example selected from the aliphatic and aromatic polyetheresteramides disclosed in EP 1 585 787 and in U.S. patents 3,839,245; 4,230,838; 4,332,920; 5,096,995; 5,604,284; 5,652,326 and 5,886,098.

Polyetheresteramides generally comprises polyamide and polyether segments linked together with ester groups. Preferred

polyetheresteramides are poylmeric systems based on

polyamide/polyether block amides commercially available from BASF under the trademarks Irgastat® P.

The antistatic additive of the present invention is present in the second layer of the antistatic multilayer film in an amount of between 20 to 50 % by weight based on the total weight of the second layer.

The antistatic multilayer film of the present invention also comprises a third layer comprising a polyolefin resin. Polyolefin resins of the present invention are for example polymers of monoolefins and diolefins, for example polyethylene, polypropylene, polyisobutylene, polybut-1 -ene, poly-4-methylpent-1 -ene, polyisoprene or polybutadiene, as well as polymers of cycloolefins, for instance of cyclopentene or norbornene, polyethylene (which optionally can be crosslinked), for example high density polyethylene (HDPE), high density and high molecular weight polyethylene (HDPE-HMW), high density and ultrahigh molecular weight polyethylene (HDPE-UHMW), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), (VLDPE) and (ULDPE) and mixtures thereof.

Polyolefin resins of the present invention are also copolymers of monoolefins and diolefins with each other or with other vinyl monomers, for example ethylene/propylene copolymers, linear low density

polyethylene (LLDPE) and mixtures thereof with low density polyethylene (LDPE), propylene/but-1 -ene copolymers, propylene/isobutylene copolymers, ethylene/but-1 -ene copolymers, ethylene/hexene copolymers, ethylene/methylpentene copolymers, ethylene/heptene copolymers, ethylene/octene copolymers, propylene/butadiene copolymers,

isobutylene/isoprene copolymers, ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate copolymers and their copolymers with carbon monoxide or ethylene/acrylic acid copolymers and their salts (ionomers) as well as terpolymers of ethylene with propylene and a diene such as hexadiene, dicyclopentadiene or ethylidene-norbomene; and mixtures of such copolymers with one another, for example polypropylene/ethylene-propylene copolymers, LDPE/ethylene-vinyl acetate copolymers (EVA), LDPE/ethylene-acrylic acid copolymers (EAA), LLDPE/EVA, LLDPE/EAA and alternating or random polyalkylene/carbon monoxide copolymers and mixtures thereof with other polymers, for example polyamides.

Preferred polyolefin resins of the present invention are

polyethylene, polypropylene or copolymers, polyethylene or polypropylene or copolymers of ethylene and 1 ,2 unsaturated alpha olefins.

In one embodiment, the antistatic multilayer film of the present invention includes a) a first layer comprising an ionomer resin, b) a second layer comprising an antistatic additive blended with an ionomer resin, wherein the antistatic additive is a permanent antistatic additive selected from the group consisting of polyetheresteramides, c) a third layer comprising a polyolefin resin. The ionomer resins of the first and second layers may be the same or different.

In another embodiment, the antistatic multilayer film of the present invention includes a) a first layer comprising an ionomer resin, b) a second layer comprising an antistatic additive blended with an ethylene acid copolymer resin, wherein the antistatic additive is a permanent antistatic additive selected from the group consisting of polyetheresteramides, and c) a third layer comprising a polyolefin resin.

The thickness of the first layer of the antistatic multilayer film is of between 5 to 15% based on the total thickness of the antistatic multilayer film. The thickness of the second layer of the antistatic multilayer film is of between 5 to 15% based on the total thickness of the antistatic multilayer film and the thickness of the third layer of the antistatic multilayer film is of between 70 to 90 % based on the total thickness of the antistatic multilayer film.

Appropriate amounts of various additives can be present in the multilayer films of the present invention. Additives can include plasticizers, stabilizers such as hydrolytic stabilizers, radiation stabilizers, thermal stabilizers, ultraviolet light stabilizers, antioxidants, ultraviolet ray absorbers, colorants, dyes or pigments, delustrants such as Ti02, fillers, fire-retardants, lubricants, reinforcing agents such as glass fiber and flakes, processing aids such as antiblock agents, release agents, anti-slip agents, slip agents such as talc, anti-block agents, other processing aids, elastomers, or mixtures thereof. The multilayer films of the present invention can be made by melt- processing using known processes such as co-extrusion, sheet extrusion, extrusion casting, extrusion coating, thermal lamination, blown film methods, powder coating and sintering, or like processes. The film can be further processed into articles disclosed below with uniaxial or biaxial stretching, axial heat sealing, thermoforming, vacuum forming, sheet folding, heat sealing, compression molding, or combinations of two or more thereof.

In one embodiment, the method for making the multilayer film according to the invention including the steps of a) providing a first ionomer resin, b) providing a second ionomer resin or an ethylene acid copolymer resin blended with a permanent antistatic additive selected from the group consisting of polyetheresteramides, c) providing a polyolefin resin, d) coextruding the resins of steps (a) to (c) in the form of a film. Preferably, the coextrusion is made by blow molding.

The multilayer film of the present invention can be formed into a shaped article such as a tray, cup, bottle, cap, lid, blister pack, any container, flooring materials, or combinations of two or more thereof that can be ideal packaging for cosmetics, powder food medicine, beverage, juice, milk, meats, cheese, fish, poultry, nuts, coffee, sauce, stews, dried fruit, food paste, soups or soup concentrate spice, condiment, personal care product (toothpaste, shaving foam, soap, shampoo, lotion), fragrances, electronic component, chemical (fragrant laundry detergent, fragrant fabric softener), or combinations of two or more thereof.

Shaped articles such as tray, cup, bottle, cap, lid, blister pack, container, cosmetics case, housing or other parts of household appliances (e.g. , handle for electric iron and housing for hair dryer, vacuum cleaner, kitchen appliance, and telephone), or combinations of two or more thereof can be produced from the multilayer films of the present invention by virtually any method of extrusion processing or thermoforming known to those skilled in this art. A melt extrusion process such as injection molding, compression molding, blow molding and profile extrusion can be used. As such, the articles can be injection molded, compression molded, blow molded, or profile extruded. The shaped articles may comprise layers of polymers other than the composition disclosed herein. A film or sheet (or even a blow molded article such as bottle), the layers can be made by coextrusion or lamination). In an injection molded part, there can be co- injection molding, which is similar to coextrusion, or overmolding. The film or sheet or blow molded article can comprise a layer comprising the composition as a distinct layer and other optional layer(s) comprising other polymers.

EXAMPLES The following structures were made on a three layers Kautex

KCC10 extrusion blow molding machine. One skilled in the art would recognize the structure can be more than three layers, but minimum is three layers. The outside layer comprises an ionomer, but it can also be a Polyamide, lonomer Blends; the middle layer or layer 2) is the antistatic blend with the Polvetherestheramide polymer and acid copolymer resin.

The machine was equipped with four 18mm extruders and one 35mm extruder. The bottle that was made was a 150ml elliptical bottle.

The following structures were made:

ION l is a EMAA (Ethylene co methacrylic acid) copolymer with 19% MAA (methacrylic acid), MFI 4.5, Neutralised with Na

ACR1 is a copolymer of ethylene and 9 wt% methacrylic acid.

Alternatively, acid copolymers with between 6 and 25 wt% of methacrylic acid can be used.

Hostalen 5831 is a HDPE (High Density Polyethylene), MFI 0.3, manufactured by Borealis

AS-1 Irgastat P16 is a copolyesteramide manufactured by BASF Delamination was measured with a 180 C degree peel test using a

Zwick tensile testing machine and a speed of 100 mm/min

Static decay was done with a static decay meter of ETS Electro Tech Systems Inc., Model 406. A charge of -5000 and +5000V was applied. Thereafter the time was measured that passes until the charge decreases to 1/10th of the original charge

A static decay time of > 100 sec means no dissipation of static charges on the surface, <1 sec means immediate static dissipation and therefore no dirt attraction. The measurement was done after conditioning the bottles for 1 week at 50%RH (Relative Humidity).

Dirt pick up testing was measured in the following manner by using dried fish flakes of Pacifc Thuna. But also dry paper flakes or dry cigarette ash can be used.

The contamination is spread on a clean table; the surface of the bottles needs to be rubbed 3-4 times back and forth on a cotton cloth. The surface needs to be brought in contact (ca 2 mm distance) to the dirt spread out on the table. Dirt pick up means: the contamination jumps onto the bottle surface. No dirt pick up means that the contamination stays on the table. The measurement was done after conditioning the bottles for 1 week at 50% RH.

The addition of a permanent, non migrating antistatic polymer such as AS-1 allows for antistatic properties on the outside surface of the object. Antistatic properties are defined by the absence of dirt pick up upon rubbing the object and by a low static decay time

Furthermore the antistatic polymer does not have to be present in the adjacent, subsurface layer can be pure form but can be blended with other polymers, such as polyolefine copolymers within a range of 20 to 60% in order provide antistatic properties while maintaining adhesion of the multilayer structure. Too low amount of ACR-1 will lead to

delamination but to low dust pick up and low static decay time. Too high amount of ACR-1 will lead to good adhesion but high static decay time and low dust pick up. An intermediate level is needed as detailed in the examples. Table 1