Methods of casting polylactic acid shrink films

[0001] The invention relates generally to a heat-shrinkable film. More particularly, the invention relates to polylactide heat-shrinkable films exhibiting thermal-dependent shrinkage in one direction, i.e. "transverse direction", with little or no shrinkage in the second direction, i.e. "longitudinal direction".

BACKGROUND OF THE INVENTION [0002] Heat-shrink films are widely used for a variety of industrial applications, such as, for example, shrink packs, shrinkable labels and screw cap seals, by exploiting their heat-shrinking properties. These foils are applied on a variety of surfaces, including plastic and glass. Shrink films are made of vinyl chloride resins, polystyrene resins or polyester resins; however, in many cases the shrinking of the film is accompanied by undesirable "pull" of the outer edges of the film (also known as "smile" or "wrinkle"). Undesirable removal of external edges limits the use of shrink films. Therefore, there is a need for shrink films that have little or no pull.

[0003] The interest in compostable polymers, i.e. biopolymers, has also increased significantly, and many companies have made efforts to market, for example, packaging materials, hygiene products, bags and films with compostable polymers. Poly (lactic acid), or polylactic acid, or condensation polymers based on lactic acid, are for many reasons a very attractive group of biopolymers. The main product of their decomposition, lactic acid, is a compound commonly found in nature, non-toxic and commonly used in the food and pharmaceutical industries.

[0004] PLA films can be made by a blow molding or casting technique (e.g., a "cast and tenner" method). While each of these methods has its advantages and disadvantages, the film formed from the solution is generally better suited for specific end applications, such as those that require foil "sleeves" instead of wrapping film. In addition, the film formed from the solution usually has a better optics than the blown film and can be produced at higher speeds of the production line. However, PLA films produced by current casting methods exhibit excessive shrinking in the longitudinal direction, which makes a significant contribution to curling and limits the range of their applications. There is therefore a need for PLA shrink films produced by casting methods and exhibiting little or no shrinkage in the longitudinal direction.

[0005] EP1491585 discloses a method for producing a shrink film from a PLA blend, which film has 40-70% shrinkage in the transverse direction and 3-8% shrinkage in the longitudinal direction after exposure to hot water at 80 ° C for 10 seconds comprising: extruding the resin through a T-shaped channel matrix; cooling the extruded film on the cooling roller; reheating the film; stretching the film in the transverse direction and, to a lesser extent, in the longitudinal direction.

SUMMARY OF THE INVENTION [0006] The invention is defined by the appended claims. The above needs are to some extent satisfied by the invention in which, in a certain embodiment, a shrink film composed of a film of a transverse oriented PLA polymer blend is provided, which film exhibits shrinkage in the transverse direction and less than about 10 when exposed to heat. % shrinkage in the longitudinal direction. In a preferred embodiment, the shrinkage in the longitudinal direction does not exceed about 5%. A shrink film subjected to about 60 ° C of heat for about 10 seconds may exhibit shrinkage in the transverse direction in the range of about 10% to about 80% and has a shrinkage in the longitudinal direction in the range of about 0% to about 5%. In certain embodiments, a shrink film subjected to about 60 ° C of heat for about 10 seconds may exhibit shrinkage in the transverse direction from about 30% to about 80% and exhibits shrinkage in the longitudinal direction from about 0% to about 3%. In other embodiments, a shrink film subjected to about 60 ° C of heat for about 10 seconds may exhibit shrinkage in the transverse direction of about 25% and have a longitudinal shrinkage of about 0% or less (negative value means growth).

[0007] PLA shrink films may additionally contain one or more additives, such as an additive to facilitate separation of the extrudate from the matrix, lubricant additive, viscosity enhancer or a combination thereof. The addition to facilitate separation may be natural silica, synthetic silica, talc, magnesium-filled talc, calcium carbonate, and N, N'-ethylene bis (stearamide) (EBS). In some embodiments, the preferred addition to facilitate separation is talc packed with magnesium. The slip agent may be oleamide, erucamide, stearamide, behenamide, oleyl palmitamide, stearyl erucamide, ethylene bis oleamide, EBS, or a combination thereof, and preferably EBS in certain embodiments. The viscosity-increasing agents may include, for example, stabilizers or coupling agents. A preferred coupling agent is CESA®-extend.

[0008] The shrink films disclosed herein from blends of PLA polymers may contain two or more PLA "species". The PLA polymer may contain, for example, from about 1 to about 2% by weight. D-lactide; from about 3 to about 5% by weight D-lactide; or from about 11 to about 13% by weight. D-lactide. In certain embodiments, the shrink films may contain from about 50% by weight. up to about 90% by weight PLA polymer containing from about 11 to about 13% by weight D-lactide; and from about 10% by mass up to about 50% by weight PLA polymer containing from about 1 to about 2% by weight D-lactide. In other embodiments, the shrink films may contain from about 60% by weight. up to about 80% by weight PLA polymer having about 11 to about 13% by weight D-lactide; and from about 20% by weight up to about 40% by weight PLA polymer having about 1 to about 2% by weight D-lactide. In still other embodiments, the shrink films may contain from about 65% by weight. up to about 75% by mass PLA polymer having about 11 to about 13% by weight D-lactide; and from about 25% by mass up to about 35% by weight PLA polymer having about 1 to about 2% by weight D-lactide.

[0009] Furthermore, the invention provides foils comprising from about 50 wt .-%. up to about 90% by weight PLA polymer having about 11 to about 13% by weight D-lactide; from about 10% by mass

up to about 50% by weight PLA polymer having about 1 to about 2% by weight D-lactide; less than about 3% by mass the addition facilitating separation; less than about 1% of the slip additive; and less than about 0.5% of a viscosifying agent. These films can also contain from about 50% by weight. up to about 90% by weight PLA polymer having about 11 to about 13% by weight D-lactide; from about 10% by mass up to about 50% by weight PLA polymer having about 1 to about 2% by weight D-lactide; less than about 2% by mass the addition facilitating separation; less than about 0.5% of the slip additive; and less than about 0.25% of a viscosifying agent. Preferably, in certain embodiments, the shrink films of the invention contain from about 50 wt .-%. up to about 90% by weight

PLA polymer having about 11 to about 13% by weight D-lactide; from about 10% by mass up to about 50% by weight PLA polymer having about 1 to about 2% by weight D-lactide; less than about 1% of the masses the addition facilitating separation; less than about 0.25% slip additive; and less than about 0.1% of a viscosifying agent.

[0010] According to another embodiment of the invention, a packaged product comprising a consumer product and a heat treated sleeve covering at least a portion of the consumer product is provided, which heat treated sleeve is obtained by subjecting heat to a shrink film PLA comprising a PLA blend that is shrinking towards the surface. transverse and less than about 10%, preferably less than about 5%, shrink in the longitudinal direction after exposure to heat. Wrapped goods can be consumer products, such as batteries, cans, bottles, disposable lighters, pens and decorative elements. The sleeve can form a perforated or unperforated neckband around the consumer product and can be transparent, matte, transparent or opaque.

[0011] In yet another embodiment of the invention, there is provided a method for producing a shrink film, comprising: (a) providing dry PLA pellets, (b) fusing the pellets to form a melt, (c) extruding the obtained melt, (d) forming the extrudate between at least three forming rolls for forming the film, (e) adjusting the temperature of the film and (f) stretching the film in the transverse direction. The method may optionally comprise drying the pellets, for example in a drying hopper, before melting the pellets to form a molten mass.

[0012] The melting step may be performed in a temperature range of about 165 ° C to about 230 ° C, preferably about 170 ° C to about 200 ° C, and more preferably at about 175 ° C. The extrusion can take place through a matrix with a T-shaped channel, and the thermal conditioning of the film can take place in a machine direction orienting (MDO) machine that can be additionally equipped with one or more loose rollers. The stretching may be carried out in a tenter (tenner), preferably in a temperature range of about 70 ° C to about 90 ° C, more preferably at about 80 ° C. In certain embodiments of the disclosed invention, the method may further comprise heating the film. Annealing can be performed in a temperature range of about 50 ° C to about 90 ° C, preferably at about 70 ° C with a 1% -5% return contraction.

[0013] In a still further embodiment of the invention, a casting machine with three or more rollers is provided. These rollers can be driven and / or temperature controlled.

[0014] Rather, it has been outlined a number of certain embodiments of the invention to allow a better understanding of the following detailed description and better appreciation of the contribution to the technique. There are, of course, additional examples of the invention that will be described below and which will be the subject of the appended claims.

[0015] Therefore, before explaining at least one embodiment of the invention in detail, it should be understood that the invention in its application is not limited to the construction details and arrangement of the components shown in the following description or illustrated in the drawings. The invention is suitable for other embodiments in addition to those described and for practicing and performing in various ways. It should further be understood that the terminology and terminology used here as well as in the summary are intended for descriptive purposes and should not be considered as limiting.

[0016] Consequently, it will be appreciated by those skilled in the art that the concept on which the disclosure is based can easily be used as the basis for designing other structures, methods, and systems to accomplish several objectives of the invention. It is therefore important that the claims are considered to include such equivalent constructions as long as they do not depart from the scope of the invention.

BRIEF DESCRIPTION OF THE FIGURES [0017]

Fig. 1 shows a schematic of the movement of the polymer film from the die by casting machines and MDO, and then into the tenter according to one embodiment of the invention. The way through the casting machine and the tenter is indicated by arrows. The general contours of the respective machines are provided with dashed lines. Wheels mean rollers.

Fig. 2 is a graph showing% shrinkage of PLA cast film ("TDO") according to the invention at a given temperature for ten seconds compared to PLA blown film ("MDO"). The contraction in both the machine direction (MD) and the transverse direction (TD) is ensured.

Fig. 3 is a graph showing% shrinkage TD of TDO PLA film according to the invention with respect to TDO film not with PLA. PLA - poly (lactic acid); TMOPS transverse monoblocked polystyrene; PETG - poly (ethylene terephthalate) modified with glycol; PVC - poly (vinyl chloride).

Fig. 4 is a graph showing the% shrinkage of the MD of the TDO PLA film according to the invention with respect to the TDO film not with PLA.

DETAILED DESCRIPTION [0018] In one embodiment of the invention, plastic films and a method for making them are described. Polymeric films are produced that, when exposed to heat, shrink in the transverse direction and exhibit little or no shrinkage in the longitudinal direction. In a preferred embodiment, the shrink films of the invention show a shrinkage, when heated, in the transverse direction of not less than about 40%, preferably not less than about 50% and most preferably not less than about 60%. Similarly, in a preferred embodiment, the shrink films of the invention show a shrinkage, in heating, in the longitudinal direction of no more than about 10%, preferably no more than about 5%, more preferably no more than about 3% and most preferably about 0% or less ( negative value means increase).

[0019] The longitudinal direction will be defined here as "longitudinal", i.e. in line with the direction of movement of the raw material by the machines. "Transverse direction" will be defined here as a direction perpendicular to the longitudinal direction. The film embodiments described herein exhibit reduced edge curl and can be produced in transparent, transparent and opaque as well as opaque colors. The films of the invention may be printable on the back side and / or on the front side.

[0020] The films of the invention may contain various polymers and grades of polylactic acid polymers ("PLA") known in the art. Preferably, in some embodiments, polymers are selected that, when used alone or in a mixture, allow "memorizing" the effect of the orientation process described herein. The skilled person knows many determinants for the selection of polymers and / or they will also obviously result from the teachings herein. For example, when high temperature processing is desired, polymers with higher softening temperatures can be selected, such as, for example, relatively high molecular weight polymers.

[0021] The shrink films of the invention comprise PLA and may optionally contain additives known in the art, e.g. separation assist additives, lubricating additives, plasticizers and "viscosity enhancing agents". These additives are usually used to improve the processing, parameters and appearance of the final product, as will be discussed below. It is understood that each of the above-mentioned classes includes various species of suitable polymers. Now, each of these classes of polymers and additives will be discussed in turn, as relevant to the invention.

PLA [0022] Both lactic acid and lactide can give the same reproducible unit, so the general terms poly (lactic acid) and polylactides as used herein refer to polymers having a repeat unit of the formula I without any limitations as to how the polymer has been obtained (e.g. from lactides, lactic acid or oligomers), and without reference to the degree of polymerization.

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[0023] The polylactide used in the invention may be prepared from L-, D- or D, Lactide, or blends thereof, in any polymerization process. The high molecular weight polymer can be obtained by ring-opening polymerization of a lactic acid dimer, lactide. Lactic acid is an optically active compound and therefore its dimer exists in four different forms: L, L-lactide; D, D-lactide; L, D-lactide ("mesolactide"); and the racemic mixture of L, L- and D, D-lactide. As a result of the polymerization of these dimers either as pure compounds or blends of varying proportions, polymers of different stereochemistry are obtained, affecting their strain energy and crystallinity, and consequently also their mechanical and thermal properties. The polymers obtained are usually hard and transparent optically.

[0024] Copolymers or polymer blends can also be used in the PLA films of the invention. The weight average molecular weight (Mw) of polymers suitable for the invention is about 10,000 to 400,000, preferably 40,000 to 250,000.

[0025] The polylactide is in equilibrium with its monomer, lactide. This chemical property can lead to rapid hydrolysis and cause adhesion problems during polymer processing. Furthermore, the presence of monomer reduces thermostability during melt processing. Therefore, the lactide residues are usually and preferably removed from the polymer. The preferred monomer content is preferably less than about 2% and more preferably less than about 1%.

[0026] During the processing steps of the film, heat may also contribute to the polymer degradation. In addition to removing the lactide monomer, another way of delaying premature polymer hydrolysis is to reduce the water content in the polymer to less than 500 ppm, and more preferably to less than 200 ppm. Methods for further reducing and / or maintaining low water content are described herein below.

[0027] PLA can be purchased from many suppliers and polymers and / or the polymer blends of the invention are not limited to any class or supplier. However, in certain embodiments of the invention, the NatureWorks® polymers provided by Cargill, Inc. are preferred. (e.g., 4060D, 4042D, 4032D species). While each of the 4060D species,

4042D and 4032D have an average molecular weight from 200,000 to about 400,000, they are obtained with different D-lactide percentages. 4042D is obtained from about 3 to about 5% by weight. D-lactide. Grade 4060D contains from about to about 13% D-lactide; polymer grade 4032D - about 1 to about 2% D-lactide.

These polymers are provided with a lactide concentration of less than about 1%, a mesolactide concentration of about 10% to about 20%, and a moisture content less than about 500 ppm.

[0028] While the PLA is suitable for any species and composition, concentration especially of D-lactide may affect the physical properties of the resulting PLA.

For example, increasing% D-lactide in a polymer or polymer blend reduces the crystallization capacity of the resulting polymer, which in turn increases undesired polymer degradation at high temperatures. In other words, reducing% by mass D-lactide in the polymer composition increases the thermal resistance of the polymer, and thus also the viscosity of the resulting alloy at a given temperature.

[0029] Polymers and / or blends of polymers with higher D-lactide contents may give films which under the influence of heat begin to shrink at lower temperatures;

these films usually also exhibit "gentler" courses of the shrinkage curve, i.e. smaller shrinkage at a given temperature increase. Conversely, films containing polymers with a relatively low D-lactide concentration usually require exposure to higher temperatures to begin to shrink. It should also be noted that typically PLA polymers with lower D-lactide concentrations are more expensive than otherwise equivalent polymers containing more D-lactide. Therefore, maximizing the use of PLA with higher D-lactide contents may be inspired by economic considerations; however, these considerations should and can be balanced with the desired physical properties of the film.

Additives to facilitate separation [0030] Additives that facilitate separation (also referred to as anti-adhesive agents) serve to improve the processing and use of polymeric films. Specifically, this class of additives is used to reduce adhesion between the film layers. The effect of the agents facilitating the separation - usually finely divided solid minerals, but also waxes - consists in causing a slight surface roughness. Separating agents are mainly used in film extrusion; these include natural silica, synthetic silica, talc, calcium carbonate, and N, N'-ethylene bis (stearamide) (EBS).

[0031] Additives that facilitate separation are usually "incorporated" together with the carrier compound. Although not required in any way, it is preferred that the carrier polymer be similar or equivalent to one or all of the polymers in the main PLA mixture. For example, it is preferred in the invention that the carrier polymer is PLA. As the &amp; quot; active ingredient &amp; quot; in the separation addition facilitates only a small fraction of the final composition, the addition of the carrier compound ensures the ease and consistency of the measurements. One skilled in the art will appreciate that filler concentration should be taken into account when calculating the final concentration of the additive to facilitate separation in the final product. For example, if the composition containing a 10% detoxification additive consists of a 10% "active ingredient", the final concentration of "active ingredient" is 1.0% of the total.

The values ​​given herein below, including Tables 1 and 2, are provided as the percentage of "active ingredient" in the final formulation.

[0032] In the invention, the final concentration of the separation promoting additive is less than about 3 wt .-%, preferably less than about 2 wt .-%. and more preferably less than about 1% by weight. In one embodiment of the invention, an additive that facilitates the separation of 2100D from Cargill is preferred. 2100D contains 10% magnesium silicate filled with talc in PLAT carrier grade 4032D and has an average particle size of less than about 1 micrometer.

[0033] One of the factors to consider when choosing a suitable separation aid is the size of its particles. In fact, the particle size of the separating agent can make a direct contribution to the overall smoothness of the resulting film. That is, if all other factors are the same, a smaller particle size of the separation aid will result in a smoother film. Another factor to consider is the concentration of the additive that facilitates separation.

The concentration of the addition to facilitate separation is particularly preferably minimized, because in some cases additives to facilitate separation may cause clouding of the film. Therefore, especially in those applications in which haziness is undesirable (e.g., windows in envelopes, etc.), the concentration of the addition facilitating separation can be minimized.

Slip additives / processing aids [0034] The processing aids are a class of agents generally supporting further manufacturing steps (i.e., post-embossing operations) of various film products. For example, lubricating additives are modifiers that act as internal lubricants to reduce the coefficient of friction (COF) between two overlapping films, for example in the case of roll-up films after fabrication. In fact, lower COF values ​​are particularly desirable in film applications. These additives migrate to the surface of the plastic during processing and immediately after it. This means that the invisible coating "blows" onto the surface, providing a microscopic "layer" of air between two adjacent sheets of film. In this way, better lubricity and slippage are ensured.

[0035] Accordingly, the slip additives may be considered similar to additives to facilitate separation in that both classes of additives cause a reduction in COF between two overlapping films. The films of the invention may contain one or both or do not contain any additive class. Typical lubricants are, for example, oleamide, erucamide, stearamide, behenamide, oleyl palmitamide, stearyl erucamide, ethylene bis oleamide, EBS, including most of their degree of fineness. In certain embodiments, the preferred glidant is EBS, and more preferable is EBS with a 4032D carrier. These and other slip additives and processing aids are commercially available under the following trade names: Adogen 42, Armid 18, Crodamid VRX, E, ER and BR,

Danimer 9205, Freeflow Z100 and Z200, Incromold, Incroslip, Kemamids, Kemamid P-181,

MoldWiz Int - 33CRS, Paraloid EXL, Uniwax 1750 and Viton. EBS is sold under the trade names Advawax, Lubrol EA and Micotomic 280.

[0036] As with separating aids, the "active ingredient" of the slip additives is usually supplied with the carrier. The films of the invention contain less than about 1% by weight. a slip additive (as applicable only to the "active ingredient"), and more preferably less than about 0.5% by mass. It should be noted that excessive amounts of the slip additive can give films with excessive smoothness, which can reduce the adhesion of the substance (e.g., ink, stickers, etc.) to the surface of the film. Thus, to increase, for example, the printability of the shrink film according to the invention, it may be necessary to adjust the amount of slip additive accordingly.

Plasticizers [0037] While the practice of the invention does not require the use of impact modifiers (also known as "plasticizers"), their use may be beneficial for processing. For example, some plasticizers may reduce brittleness. Many plasticizers are known in the art and the invention is not limited in their use. Non-limiting examples include: commercially available plasticizers, e.g. mono- and polycarboxylic esters, polymer polyesters, poly (alkyl ethers), glycerol and glycol esters (e.g., glycerol triacetate and glycerol tripropionate), aliphatic and aromatic low molecular weight polyesters, and their mixtures. Also suitable are various polymeric plasticizers, such as citrate esters, adipate esters, epoxidized soy oils, acetylated coconut oil, linseed oil and mixtures thereof. It is also commonly understood that the addition of lactic acid, lactides (including D- and L-lactide, meso- and racemic D, L-lactide), oligomers of lactic acid, oligomers of lactide and mixtures thereof to the PLA blend, may act as a polymer plasticizer. .

Viscosity-increasing agents [0038] Although numerous methods for increasing the viscosity of polymers during film processing using the "cast and tenner" method are known and available, the term "viscosity-increasing agent" is defined herein as including any chemical agent that increases or maintains the viscosity of the polymer in a given temperature. The viscosity-increasing agents can be incorporated into the polymer blend at any time before the polymer is incorporated in the matrix (as discussed below), however, these preferred agents are incorporated prior to extrusion, and more preferably when blending the polymer pellets.

[0039] Viscosity enhancers can improve the properties of the finished film, preventing the degradation occurring during processing of the polymer films and / or reversing it. Some viscosity agents are "stabilizers". That is, they are used in unmodified plastic to (1) protect against degradation during processing and / or (2) reverse the degradation caused by recycle and restore the plastic close to the original. Another class of viscosity agents, "coupling agents", for example, improve the processability of the extruded polymer by "coupling" (combining) the separate polymer strands, which increases the strength of the plastic alloy.

[0040] Viscosity-increasing agents are commonly known and available to those skilled in the art, and have the widest application in the case of polyesters, polyamides (nylons) and polycarbonates. Although the chemical identity of viscosity enhancers is usually proprietary, these products are available from such retailers as Johnson Polymer LLC (USA) and Clariant International Ltd. (Switzerland). The viscosity enhancers suitable for the invention are not limited to those given herein by way of example, nor to agents with similar mechanisms. In fact, any chemical agent that increases or maintains the viscosity of the polymer at a given temperature may be sufficient.

[0041] In a preferred embodiment of the invention, shrink films are produced comprising a coupling agent to increase viscosity. One such coupling agent, CESA®-extend, is available from Clariant. These viscosity-increasing agents include a proprietary copolymer of styrene, methyl methacrylate and glycidyl methacrylate. Without being limited or bound by theory, it is believed that the CESA®13 extend viscosity enhancers, by coupling separate PLA polymers, repair damage (e.g., polymer degradation) that can be induced in PLA resins by heat and moisture. In this way, the viscosity enhancing agent can "lengthen" the polymer chains with some degradation and thereby reduce the overall decrease in molecular weight and melt viscosity of the polymer melt.

[0042] Optimal CESA®-extend reactivity can be achieved at a preferred level of less than about 0.15 mass%, and preferably less than about 0.75 mass%. active ingredient. And here, the "active ingredient" of the viscosity-increasing agents is usually supplied with the carrier. CESA®-extend viscosity enhancers can be subjected to a residence time of about 2 to about 20 minutes, depending on the initial humidity and / or the natural initial viscosity of the polymer. The residence times are also preferably minimized to reduce the degradation of the polymer due to the heat required in the process. A detailed discussion of processing conditions is provided below. In any case, the skilled artisan will appreciate that it may be necessary to adjust the concentration of any polymer improver based on at least some of the factors mentioned above.

[0043] In certain embodiments, the film polymers can be selected from one or more five groups (i.e., PLA, separation assist and slip additives, plasticizers, viscosity enhancers) and combine to form mixed polymeric films. Tables 1 and 2 below provide non-limiting examples of formulations that may be suitable for the preparation of a film of the invention. The skilled person should realize that in the teachings presented here for the sake of clarity, the calculated% of additives applies only to the "active ingredient". In other words, although it should be understood that additives are usually provided in a combination of "active ingredient" and vehicle, the% vehicle, if any, was not given.

Table 1. Polymer formulations

<td rowspan="2">^LP.</td><td colspan="6">Composition (in% by mass)</td>

<td>4060D</td><td>4042D</td><td>4032D</td><td>Easy addition separation</td><td>Center sliding</td><td>The increasing agent viscosity</td>

<td>1</td><td>69.58%</td><td>0%</td><td>thirty%</td><td>0.15%</td><td>0.18%</td><td>0.09%</td>

<td>2</td><td>97.50%</td><td>0%</td><td>0%</td><td>1.50%</td><td>0.50%</td><td>0.50%</td>

<td>3</td><td>0%</td><td>0%</td><td>99.58%</td><td>0.15%</td><td>0.18%</td><td>0.09%</td>

<td>4</td><td>0%</td><td>0%</td><td>97.50%</td><td>1.50%</td><td>0.50%</td><td>0.50%</td>

<td>5</td><td>0%</td><td>98,58%</td><td>0%</td><td>0.15%</td><td>0.18%</td><td>0.09%</td>

<td>6</td><td>0%</td><td>98%</td><td>0%</td><td>1.50%</td><td>0.50%</td><td>0.50%</td>

<td>7</td><td>98,58%</td><td>0%</td><td>0%</td><td>0.15%</td><td>0.18%</td><td>0.09%</td>

<td>8</td><td>59.58%</td><td>10%</td><td>thirty%</td><td>0.15%</td><td>0.18%</td><td>0.09%</td>

<td>9</td><td>49.58%</td><td>20%</td><td>thirty%</td><td>0.15%</td><td>0.18%</td><td>0.09%</td>

<td>10</td><td>39.58%</td><td>thirty%</td><td>thirty%</td><td>0.15%</td><td>0.18%</td><td>0.09%</td>

<td>11</td><td>48.61%</td><td>thirty%</td><td>20%</td><td>1.12%</td><td>0.18%</td><td>0.09%</td>

<td>12</td><td>48%</td><td>thirty%</td><td>20%</td><td>1.00%</td><td>0.50%</td><td>0.50%</td>

<td>13</td><td>thirty%</td><td>20%</td><td>48%</td><td>1.00%</td><td>0.50%</td><td>0.50%</td>

<td>14</td><td>thirty%</td><td>thirty%</td><td>39.58%</td><td>0.15%</td><td>0.18%</td><td>0.09%</td>

<td>15</td><td>thirty%</td><td>0%</td><td>68.85%</td><td>0.15%</td><td>0.50%</td><td>0.50%</td>

<td>16</td><td>68.85%</td><td>0%</td><td>thirty%</td><td>0.15%</td><td>0.50%</td><td>0.50%</td>

<td>17</td><td>0%</td><td>68.85%</td><td>thirty%</td><td>0.15%</td><td>0.50%</td><td>0.50%</td>

<td>18</td><td>thirty%</td><td>68.85%</td><td>0%</td><td>0.15%</td><td>0.50%</td><td>0.50%</td>

<td>19</td><td>29.58%</td><td>thirty%</td><td>40%</td><td>0.15%</td><td>0.18%</td><td>0.09%</td>

<td>20</td><td>70%</td><td>0%</td><td>29%</td><td>0.50%</td><td>0.25%</td><td>0.25%</td>

<td>21</td><td>29%</td><td>0%</td><td>70%</td><td>0.50%</td><td>0.25%</td><td>0.25%</td>

<td>22</td><td>99%</td><td>0%</td><td>0%</td><td>0.50%</td><td>0.25%</td><td>0.25%</td>

<td>23</td><td>0%</td><td>99%</td><td>0%</td><td>0.50%</td><td>0.25%</td><td>0.25%</td>

<td>24</td><td>0%</td><td>0%</td><td>99%</td><td>0.50%</td><td>0.25%</td><td>0.25%</td>

<td>25</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td>

<td>26</td><td>0%</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td>

<td>27</td><td>0%</td><td>0%</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td>

<td>28</td><td>0%</td><td>0%</td><td>0%</td><td>100%</td><td>0%</td><td>0%</td>

<td>29</td><td>99.63%</td><td>0%</td><td>0%</td><td>0.10%</td><td>0.18%</td><td>0.09%</td>

<td>thirty</td><td>0%</td><td>99.63%</td><td>0%</td><td>0.10%</td><td>0.18%</td><td>0.09%</td>

<td>31</td><td>0%</td><td>0%</td><td>99.63%</td><td>0.10%</td><td>0.18%</td><td>0.09%</td>

<td>32</td><td>99.68%</td><td>0%</td><td>0%</td><td>0.05%</td><td>0.18%</td><td>0.09%</td>

<td>33</td><td>0%</td><td>99.68%</td><td>0%</td><td>0.05%</td><td>0.18%</td><td>0.09%</td>

<td>34</td><td>0%</td><td>0%</td><td>99.68%</td><td>0.05%</td><td>0.18%</td><td>0.09%</td>

<td>35</td><td>thirty%</td><td>thirty%</td><td>39.68%</td><td>0.05%</td><td>0.18%</td><td>0.09%</td>

<td>36</td><td>39.68%</td><td>thirty%</td><td>thirty%</td><td>0.05%</td><td>0.18%</td><td>0.09%</td>

<td>37</td><td>0%</td><td>39.68%</td><td>thirty%</td><td>0.05%</td><td>0.18%</td><td>0.09%</td>

<td>38</td><td>70%</td><td>0%</td><td>29.3%</td><td>0.1%</td><td>0.6%</td><td>0%</td>

Table 2. Polymer formulations

<td rowspan="3">Lp.</td><td colspan="6">Composition (in% by mass)</td>

<td>4060D</td><td>4042D</td><td>4032D</td><td>An addition to facilitate separation</td><td>Slip agent</td><td>softener</td>

<td></td><td></td><td></td><td></td><td></td><td></td>

<td rowspan="2">39</td><td rowspan="2">70%</td><td rowspan="2">0%</td><td>24.3%</td><td rowspan="2">0.10%</td><td rowspan="2">0.60%</td><td rowspan="2">5%</td>

<td></td>

<td rowspan="2">40</td><td rowspan="2">70%</td><td rowspan="2">1%</td><td>24.3%</td><td rowspan="2">0.10%</td><td rowspan="2">0.60%</td><td rowspan="2">4%</td>

<td></td>

<td rowspan="2">41</td><td rowspan="2">65%</td><td rowspan="2">5%</td><td>26.3%</td><td rowspan="2">0.10%</td><td rowspan="2">0.60%</td><td rowspan="2">3%</td>

<td></td>

<td rowspan="2">42</td><td rowspan="2">68%</td><td rowspan="2">2%</td><td>28.3%</td><td rowspan="2">0.10%</td><td rowspan="2">0.60%</td><td rowspan="2">1%</td>

<td></td>

<td rowspan="2">43</td><td rowspan="2">70%</td><td rowspan="2">5%</td><td>24.3%</td><td rowspan="2">0.10%</td><td rowspan="2">0.60%</td><td rowspan="2">0%</td>

<td></td>

<td rowspan="2">44</td><td rowspan="2">70%</td><td rowspan="2">0%</td><td>29.3%</td><td rowspan="2">0.10%</td><td rowspan="2">0.60%</td><td rowspan="2">0%</td>

<td></td>

<td rowspan="2">45</td><td rowspan="2">70%</td><td rowspan="2">0%</td><td>24.5%</td><td rowspan="2">0.10%</td><td rowspan="2">0.40%</td><td rowspan="2">5%</td>

<td></td>

<td rowspan="2">46</td><td rowspan="2">70%</td><td rowspan="2">0%</td><td>24.7%</td><td rowspan="2">0.10%</td><td rowspan="2">0.20%</td><td rowspan="2">5%</td>

<td></td>

<td rowspan="2">47</td><td rowspan="2">70%</td><td rowspan="2">0%</td><td>24.3%</td><td rowspan="2">0.05%</td><td rowspan="2">0.65%</td><td rowspan="2">5%</td>

<td></td>

<td>48</td><td>70%</td><td>0%</td><td>24.3%</td><td>0.15%</td><td>0.55%</td><td>5%</td>

<td>49</td><td>70%</td><td>0%</td><td>24.3%</td><td>0.25%</td><td>0.45%</td><td>5%</td>

[0044] The blends in the above tables can be selected or obtained to create a "shank" or elasticity of the films suitable for end use. When all other processing parameters are equal, the ratio of the PLA polymers of the invention can be modified to provide shrink films with the desired physical properties. For example, a reduction in D-lactide concentration (i.e., an increase in wt.% 4032D) results in polymers with a higher softening point and foils that require a higher temperature to induce shrinkage, which shifts the shrink curve to the right.

[0045] While the formulations listed in the above tables have been categorized based on the presence of a viscosity enhancer (Table 1) or plasticizer (Table 2), the formulations of the invention may contain both a viscosity enhancing agent and a plasticizer. Furthermore, all formulations (i.e. PLA blends) may contain one or more "color corrective" dyes. Such dyes, known and available to those skilled in the art, are usually added to color the film (e.g., from the yellow to blue range) so that the film is better suited for printing. The concentration of color correcting dyes is usually in the range of about 0.002% -0.009%, preferably about 0.006% by weight.

[0046] In a preferred embodiment, the films are produced using a blend of approximately 94% by weight. PLA polymer and less than about 6% by mass additives, where the PLA component contains about 70% by weight 4060D PLA and 24% by mass 4032D. In another preferred embodiment, the films are made using a blend of polymers according to Formula 39.

Processing [0047] After selecting the polymer film composition, the polymer is processed to produce a film with the desired shrinkage. Typically, the polymers are provided in pellets or granules. In cases where the use of many polymers is provided, the polymer pellets are first dry blended. This means that the pellets are mixed with each other. In a preferred embodiment of the invention, the pellets are subsequently processed into film by the "cast and tenner" technology.

[0048] Processing by the "cast and tenner" method involves extruding molten polymers through a slit or flat matrix to form a thin melt sheet or film. The foil is first "polished" over the surface of the cooling roller (usually chrome-plated, with temperature regulation). The film is then rewound by the orientation machine in the longitudinal direction ("MDO") for thermal conditioning and stretched over the tenter frame. Finally, the edges of the film are cut, and then the film is rolled up.

[0049] The "cast and tenner" type method can thus be characterized by four essential steps: extrusion, solution forming, thermal conditioning and stretching. The initial drying step for the polymer pellets is advantageous but not required. The final soaking stage can also be beneficial, but it is not required according to the teachings. The assembly for each processing step is shown generally in FIG. 1 and will now be described in detail.

Drying [0050] PLA polymers are usually supplied in sealed bags from the manufacturer and in a relatively dry condition. Typically, the moisture content of these PLA polymers provided is less than about 500 ppm and preferably less than about 200 ppm. When the moisture level is deemed desirable, further drying may be unnecessary or unnecessary. However, the PLA readily absorbs moisture from the atmosphere and therefore the blended polymer pellets are first optionally and preferably dried by heating in a dryer to remove surface moisture. Without being bound or limited by theory, it is believed that removal of moisture can help control the relative decrease in viscosity caused by hydrolysis. As mentioned above, higher temperatures and the presence of even a small amount of moisture can hydrolyze the PLA in the subsequent melt phase.

[0051] PLA is usually prepared by a reversible condensation reaction in which water is formed; when heating the unwashed PLA, hydrolysis may take place and the key mechanical properties of the PLA may deteriorate. For example, the viscosity of the polymer after melting is inversely proportional to its percentage of free monomer. Therefore, in an attempt to minimize the viscosity differences between the batches, preferably a significant moisture is removed from the polymer pellets. In some embodiments, a moisture content of less than about 200 ppm is preferred, and more preferably a content of less than about 50 ppm (as measured by the Karl Fischer method).

[0052] A drying basket with hot air of a relatively low dew point may be used, however, various air dryers are known in the art and many of them may be suitable for drying. The invention need not be limited only to air dryers, but may include other types of dryers, including firing furnaces. In certain embodiments, a drying hopper may be desirable in this regard that dehumidified air passes through a PLA bed to extract moisture from the resin. Moisture from the recirculated air is absorbed by a drying agent, such as silica. Systems with a double bed of drying agent are common, so one bed is used while the reserve bed is regenerated. Switching of the air stream between one bed and the other takes place on a time-cycle basis or detection of a predetermined dew point drop. Such methodology is considered effective in removing parts of moisture that may be below the surface of polymer pellets in addition to surface moisture.

[0053] Preferred dryers according to the invention for drying PLAs may have one or more of the following features:

1. Dehydrator beds capable of achieving a dew point of about -40 ° C.

2. A measure to eliminate or reduce the probability of occurrence of temperature jumps in the air supplied, e.g. an oiling device.

3. Excellent temperature control in the PLA drying range.

[0054] The temperature and drying time may depend on the total amount and condition of the polymer (s) (i.e., the initial amount of surface moisture), and may need to be adapted to a given batch of polymer. Preferably, at this stage, the polymers only melt or none at all. For example, typical drying conditions require temperatures in the range of about

40 ° C to about 110 ° C and preferably from about 55 ° C to about 90 ° C for varying periods. In a specific example, the residence time of the air-cured polymer (dew temperature -40 ° C) with a flow rate of more than about 0.5 ft³/ min [approx. 14.1 dm³/ min] must be approximately 4 hours at approximately 40 ° C and approximately 2 hours at approximately 90 ° C.

Higher drying temperatures can cause softening and blocking of the polymer, while lower drying temperatures can lead to extended drying times and / or incomplete drying.

[0055] The dew point is an absolute measure of air humidity and does not depend on the air temperature. Dew temperature can be used to control the operation of the dryer. Another factor of drying is the air flow, because it heats the resin and absorbs moisture. Sufficient air flow can keep the resin at the right temperature for the entire residence time. In embodiments where additional dyes, additives or other ingredients are used, it may be advantageous to minimize degradation caused by moisture by further drying.

Extrusion [0056] Extrusion is a step in which the pellets are melted into a low viscosity mass, which results in combining the previously separate polymer beads or granules into one molten mass. The melt viscosity will depend on the temperature. Temperatures may range from the approximate temperature at which the polymers will remain fused to the approximate temperature at which degradation of the polymers begins. For example, the temperatures of the extrusion alloy may be maintained in the range of about 165 ° C to about 230 ° C for certain PLA blends, but may ultimately depend on the particular polymers that have been blended and their melting points. In some embodiments, a temperature of about 175 ° C is preferred.

[0057] The molten plastic is then extruded through a matrix with a T-shaped channel with a flat outlet slot. This hole will be adjusted to adjust the thickness of the finished film. In other words, a wider opening should be used when thicker foils are desired, and vice versa. Typically, the hole size will range from about 0.01 inches to about 0.10 inches [0.254-2.54 mm] and preferably from about 0.05 inches to about 0.07 inches [1.27- 1.78 mm]. The drawing distance (i.e. the distance between the die and the casting rollers) can also affect the thickness of the resulting film. Typically, the larger this length, the thinner the film, and vice versa. Without being bound or limited by theory, it is believed that larger drawing distances introduce undesirable orientation in the longitudinal direction in the resulting film. Thus, although drawing distances can range from 0.75 inches to about 1.5 inches [19-38 mm], shorter distances are preferred. A drawing distance of approximately 0.750 inches [19 mm] is usually adequate.

Casting [0058] Relatively hot (e.g., from about 175 to about 190 ° C) plastic from the extruder is then "cast" between at least two rollers. Without being bound or limited by theory, the temperature of the casting rollers should be adjusted so as to cause a rapid cooling of the outer surface of the extrudate to form a "skin" which will cause the extrudate to adhere to the rollers. At the same time, it should be kept at a sufficiently high temperature of the rollers so that the "core" of the extrudate remains flexible so that it allows the extrudate to curve around the rollers without breaking or cracking.

[0059] Typical casting machines in the art are equipped with one or two rollers where the plastic moves from the die, around one large roller or between two rollers, and then to the machine orientating in the longitudinal direction. The inventors have discovered, however, that although typical casting machines are suitable for obtaining the films of the invention disclosed herein, the novel use of a third roller in a casting machine is advantageous in the production of a film, especially when increased surface quality of the film is desired. In fact, it is believed that the use of three or more rollers in the production of PLA film, especially PLA thin film (e.g., film with a thickness less than about 0.002 inches [about 0.05 mm]), did not take place.

[0060] It is believed that the use of a third roller or more rollers is one of the reasons for significantly improving the production rate. Typically, the film is cast at a rate of about 130 feet / min [approx. 39.6 m / min], the process described here provides a production line speed of around 250 ft / min [76.2 m / min]. Without being bound or limited by theory, it is believed that an additional roller or rollers help to align the higher core temperature with the lower temperature of the epidermis. Accordingly, the third roller (or rollers) is preferably kept at a higher temperature than the first two rollers.

[0061] For example, all casting rolls may have relatively low temperatures (e.g., from about 20 to about 45 ° C, preferably from about 30 ° C to about 40 ° C, for the first two shafts, and from about 40 to about 65 ° C, preferably from about 55 to about 60 ° C, for the third roller). Roller temperatures can be maintained with liquids such as water and oil. A preferred coolant for casting rollers is water because of its greater thermal capacity than most conventional liquids. Typically, water can remove three times more heat (BTU) than oils designed for this purpose.

[0062] The teachings presented herein should inform the skilled man that the absolute temperature of the rolls will depend on several factors, including the initial temperature and the thickness of the extruded plastic. Thus, the roller temperatures given herein should not be regarded as limiting for all embodiments of the invention, but rather as exemplary values ​​from the ranges for certain embodiments. Instead, the temperature of the rollers can and should be adapted to the hole thickness in the die, the extent of stretching and the like. For example, in one embodiment, the first shaft has a set temperature of about 40 ° C, the second about 32 ° C, and the third - about 57 ° C.

[0063] In fact, the temperature of the extruded film at the exit of the casting machine is more important than the absolute temperature of any casting roller.

The temperature of the film at the exit of the casting machine is preferably from about 55 ° C to about 75 ° C, and more preferably around 60 ° C.

[0064] In addition to regulating the temperature of the plastic arriving from the die, casting rollers can also be used to modify the thickness of the plastic. This modification is performed by pre-setting the gap between the rollers to the desired thickness. For example, the gap between the first two rollers is preferably 2-10 times, more preferably 5-7 times wider than the final desired film thickness. Similarly, the gap between the second and third rollers is preferably 3-9 times, more preferably 4-6 times wider than the final desired film thickness.

Thermal conditioning [0065] The next step in obtaining the film of the invention is thermal conditioning. "Thermal conditioning" refers to the process of leveling the temperature of a plastic film so that the temperature difference between the core and the epidermis is as small as possible, if not zero. Although an MDO machine can be used in this process, preferably the orientation (i.e., stretching) in the longitudinal direction ("MD") is minimized, because stretching in MD leads to undesired shrinkage in the MD.

[0066] Various measures may be taken to limit or avoid stretching in the MD when using an MDO machine. For example, the speed of MDO rollers can be adjusted to minimize "pulling" the film from one roller to the next. For example, similar roller speeds can be maintained. (The risk of film pulling occurs when the next roller rotates faster than the previous one). As an alternative to the stretching in MD, the distance between the rollers can contribute

MDO and their location. For example, the film is usually less obliquely drawn horizontally.

[0067] The inventors have found that the novel use of "loose" rollers to bypass some MDO rollers is advantageous in terms of reducing stretching in MD.

The loose rollers are not motorized and therefore remain "idle" when the film does not run around them. Loose shafts can have a controlled temperature, but they do not have to. The number and position of loose shafts are not limiting and can be modified to suit specific processing parameters. In one embodiment of the invention, two loose rollers are provided to bypass the two middle rollers in the MDO machine (Figures 1 A and B).

[0068] As with the casting rollers, the temperature of the extruded film at the exit of the MDO machine is more important than the absolute temperature of any MDO roll. In fact, it may be necessary to adjust the temperature of the rollers to the thickness, desired stretch, etc. Preferably, the temperature of the film is aligned to between about 60 ° C and about 90 ° C and more preferably at about 70 ° C. In one embodiment of the invention, a MDO machine with 6 drive shafts and two loose shafts as shown in Figure 1 is used: roller 4 has a temperature of about 72 ° C, roller 5 has a temperature of about 85 ° C, loose shafts 6 and 7 have no temperature control, the shaft 8 has a temperature of about 85 ° C, and the shaft 9 has a temperature of about 60 ° C.

Stretching machine [0069] After the thermal conditioning, the extruder enters the tenter. The machine is equipped with tenter clamps that grip the edge of a plastic film, typically about 20 inches wide [50.8 cm]. The stretcher is equipped with an "A-shaped frame" that stretches the plastic foil to about 4 times the initial width (e.g. from 20 inches to 80 inches [203,2 cm]).

[0070] Furthermore, the tenter consists of three temperature controlled zones along the A-shaped frame. The preheating zone is provided for uniformly increasing the temperature of the polymer and guaranteeing the temperature equalization of the film core with the temperature of its skin. The stretch zone maintains the proper stretching temperature. The teachings presented here will realize that the stretching temperature will have to be adapted to the given PLA mix, practices and experience available to the experts. In one embodiment, however, this temperature is the same as the temperature in the preheat zone, which is from about 70 ° C to about 90 ° C, more preferably about 80 ° C. The end zone is an annealing zone.

Annealing [0071] Annealing, also referred to as crystallization or stress relief, is usually the final step of obtaining the film of the invention. According to the teachings here, the soaking stage is possible. When desired, annealing is usually performed after stretching, at temperatures of about 49 ° C to about 90 ° C, preferably around 70 ° C. During annealing, the film relaxes slightly. Concentration grades are typically from about 0.5% to about 5%, and preferred - about 3% or less. Finally, the edges of the stretched film are cut and wound onto rollers using conventional means.

[0072] The skilled person may manipulate the properties of the film obtained in accordance with the above-mentioned protocol according to needs by trial and error. Such variations are expected and within the scope of the invention. The films of the invention may typically have features that fall within the following ranges:

Shrink the film at about 60 ° C for about 10 seconds:

in the transverse direction: from about 10% to about 70%, with an average value of about 25%.

in the longitudinal direction: from about -2% to about 1%, with an average value of about 0%.

[0073] In one embodiment of the invention, the dependence of% shrinkage on the temperature was examined using e.g. a 200 gauge (0.002 inch) thick film (about 0.05 mm) thickly heat treated for 10 seconds (Figure 2). The films investigated here were prepared from a mixture of about 70% PLA grade 4060D, about 26% PLA grade 4032D, about 1% additive to facilitate separation of 2100D species, in which 10% is an "active ingredient", and about 3% slip EBS, in which 20% is an active ingredient. (The term &amp; quot; about &amp; quot; has been used herein and throughout the specification to account for ordinary variation in mass, temperature and% shrinkage measurements, common and expected by a skilled practitioner of the technique).

[0074] Using the process described above, a polymer blend was extruded without additional drying at about 190 ° C, and then extruded through a T-shaped die with a hole width of about 0.070 inches [approx. 1.78 mm]. The foil was then cast between three rollers at a temperature of about 40 ° C, 32 ° C and 57 ° C, successively to give a film temperature of 65 ° C. The film was then thermally conditioned in an MDO machine equipped with six driven rollers and two loose rollers as shown in Figure 1. This step gave a film temperature of about 70 ° C. Finally, the film was stretched four times in a tenter, heated to about 70 ° C, trimmed and folded.

[0075] The film was placed in a hot water bath with the temperature shown for the times indicated and a diagram of the longitudinal (MD) and transverse (TD) shrinkage as a% of the original dimensions was drawn up. Although the shrink films tested in this example have been treated with heated water, exposure to any form of heat (e.g., heated air from a hot air dryer) can cause shrinkage of the film of the invention. As can be seen from the results, the foils described show shrinkage towards TD and small or no shrinkage towards MD. For example, at about 60 ° C, the film of the invention shrinks over 25% in TD and less than 1% in MD.

[0076] The shrinkage of the films of the invention was also compared to a PLA blown film (Figure 2) and cast / tenner films containing polymers other than PLA (Figures 3 and 4). Fig. 2 shows that the films ("TDO") show greater shrinkage than the blown "MDO" films in TD at a given temperature. Fig. 3 shows that the TD shrinkage curve of the PLA film, although of comparable size, occurs at a lower temperature than that of the TDO film without PLA. For example, TDO PLA may shrink by more than 60% in TD at approximately 70 ° C, whereas TDO PETG must be heated to approximately 80 ° C to shrink by the same amount. Efficient shrinkage at lower temperatures is particularly desirable in applications where heat can harm the packaged product, such as, for example, in dairy products. Thus, TDO PLA films according to the invention have a better effect than TDO PETG when pre-labeled bottles (e.g. milk packaging and / or dairy products) are preferably kept at the lowest operating temperature. Finally, Figure 4 shows that: (1) show shrinkage in MD accompanying shrinkage in MD and (2) shrinkage may occur at relatively low temperatures. For example, TDO PETG shrinks in the MD before it shrinks in the TD, which leads to unwanted pulling on the edges. (1) show shrinkage in MD accompanying shrinkage in MD and (2) shrinkage may occur at relatively low temperatures. For example, TDO PETG shrinks in the MD before it shrinks in the TD, which leads to unwanted pulling on the edges. (1) show shrinkage in MD accompanying shrinkage in MD and (2) shrinkage may occur at relatively low temperatures. For example, TDO PETG shrinks in the MD before it shrinks in the TD, which leads to unwanted pulling on the edges.

[0077] This increase in the transverse direction may prevent the label from curling at the edges during the shrinking process. Accordingly, in one embodiment, the films of the invention may find use in the manufacture of sleeve labels (i.e., tubes) for a variety of cylinder shapes and cones, such as, for example, batteries, cans, bottles, disposable lighters, pens, films for wrapping flowers and other decorative elements. However, the range of applications will not be limited to the aforementioned consumer products or applications.

[0078] The films of the invention have innumerable other applications. For example, these films can also be used in printed / unprinted form to hold together dual packets, components, neck bands and perforated neck bands for decoration or use indication, to name but a few possibilities.

[0079] Numerous features and advantages of the invention are evidently apparent from the detailed description, and therefore the object of the appended claims is to cover all such features and advantages of the invention that fall within the scope of the invention. In addition, if many modifications and variations occur readily to those skilled in the art, it is not desirable that the invention be limited to the illustrated and described construction and operation, and accordingly all relevant modifications and counterparts can be included in the scope of the invention. invention.