[0001] The present appl ication clai ms the benefit of U.S. Provisional Patent Application No. 62/268,079 filed on December 16, 2015, which is incorporated herein by reference i n its entirety.

FIELD

[0002] The present subject matter relates to methods for reducing label defects when labeling plastic containers such as bottles. The present subject matter also relates to labels for improved application to such containers. The present subject matter additionally relates to labeled contai ners.

BACKGROUND

[0003] Plastic bottles or similar containers are typical ly used to store liquids such as water, soft drinks, motor oi l, mil k, cooking oi l, consumer healthcare products such as shampoo and soap, and inks. They are also used to store solids such as cat litter, pet food products, consumer food products such as coffee, and other foodstuffs. Plastic bottles are popular with manufacturers, distributors, and consumers due to thei r light weight and relatively low production costs as compared to glass bottles.

[0004] Plastic bottles are formed using a variety of techniques depending upon the choice of material and application. However, most manufacturi ng techniques i nvolve heati ng the polymeric material above its melting temperature and then forming the material into a desi red shape by molding, and i n many appl ications by stretch blow molding.

[0005] Many bottle manufacturers or recyclers also apply labels after formi ng bottles. However, if labels are applied to a newly manufactured bottle, a variety of label defects often occur such as formation of bubbles, darts, wri nkles, or the l ike. As a result of this phenomenon, manufacturers typical ly store newly formed bottles for pre-designated periods of time before label li ng. These bottle storage periods are referred to i n the industry as "dwell times." Dwell times can be as long as 72 hours. The i ndustry has several theories as to why bottle dwell storage reduces the occurrence of label defects. One theory is that the bottle requires time to attai n di mensional stability as shrinkage may occur as the bottle cools to ambient temperature after molding. Regardless, storing bottles after their manufacture is costly and can requi re significant storage and inventory tracking systems particularly for high speed and conti nuous bottle manufacturing processes. This can represent a significant cost of storage and the potential for graphics to change, which wi ll create waste.

[0006] Accordi ngly, a need exists for a strategy by which plastic containers could be labelled soon after their manufacture and bottle dwell storage could be avoided or at least the time period for such could be reduced.

SUMMARY

[0007] The difficulties and drawbacks associated with previously known practices are addressed i n the present label constructions, labeled contai ners, and methods.

[0008] I n one aspect, the present subject matter provides a label assembly comprising at least one fi lm layer exhibiti ng a moisture vapor transmission rate (MVTR) of from 0.50 to 2.00 g/(m ² per day) and an oxygen transmission rate (OTR) of from 800 to 1,700 cc/(m ² per day). The label assembly also comprises a layer of an adhesive disposed along the at least one film layer. The fi l m has a MD modul us of from 50,000 to 300,000 psi.

[0009] I n another aspect, the present subject matter provides a labeled polymeric contai ner comprising a polymeric container, and a label assembly. The label assembly i ncludes (i) at least one film layer exhibiti ng a moisture vapor transmission rate (MVTR) of from 0.50 to 2.00 g/(m ² per day) and an oxygen transmission rate (OTR) of from 800 to 1,700 cc/(m ² per day), and (ii) a layer of an adhesive disposed between the at least one fil m layer and the contai ner. The fil m has a MD modul us of from 50,000 to 300,000 psi.

[0010] I n yet another aspect, the present subject matter provides a method of label ing polymeric contai ners. The method comprises selecting a particular label assembly that incl udes at least one fil m layer exhibiting a moisture vapor transmission rate (MVTR) of from 0.50 to 2.00 g/( m ² per day) and an oxygen transmission rate (OTR) of from 800 to 1,700 cc/( m ² per day), and a layer of an adhesive disposed along the at least one fil m layer, i n which the fi l m has a MD modul us of from 50,000 to 300,000 psi. The method also comprises applying the label assembly to the polymeric container.

[0011] I n another aspect, the combi nation of fil m and adhesive yields a result in which the rate at which the bottle is emitting gases ( referred to outgassi ng) does not cause label defects due to the adhesive having proper co-adhesive strength and rheological properties to allow the gas to escape and the adhesive to flow around bubbles of gas in such a way that no visual channel or other evidence the emitted gas has passed through the adhesive is visual ly evident. Additional ly, the fil m has an MVTR and OTR which is sufficient to allow the emitted gas to permeate the fil m rather than being trapped at the interface between the film and adhesive layer, further avoidi ng defects. I n one i nstance, the modulus of the fil m is selected to conform to the container while not incurring defects from the movement of the labeled article, adhesive, and/or film during the shri nkage and outgassing process of the bottle. [0012] As will be realized, the subject matter described herei n is capable of other and different embodiments and its several details are capable of modifications i n various respects, all without departing from the claimed subject matter. Accordingly, the drawings and description are to be regarded as il lustrative and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic cross sectional view of a label construction i n accordance with an embodi ment of the present subject matter.

[0014] Figure 2 is a schematic cross sectional view of the label construction of Figure 1 applied to a polymeric substrate.

[0015] Figure 3 is a schematic perspective view of a labeled container in accordance with another embodiment of the present subject matter.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The present subject matter provides particular label constructions that can be applied to newly manufactured polymeric contai ners such as bottles, and which i n many appl ications do not require dwell storage. In the event that dwell storage is stil l used for containers labeled in accordance with the present subject matter, the dwell storage ti me period is significantly reduced as compared to a comparable conventional label. In accordance with the present subject matter, the label constructions can be applied to a plastic bottle i mmediately or substantially so, after manufacture of the bottle. The present subject matter also provides labeled substrates and labeled containers such as bottles. And, the present subject matter provides various methods associated with labeling containers, and methods for reducing the occurrence of label defects. These aspects are al l descri bed i n greater detai l herei n. [0017] The terms "bottle" and "contai ners" are used i nterchangeably herei n unless noted otherwise. These terms encompass nearly any thin wall polymeric contai ner for storing l iquids. As previously noted, an example of such containers is plastic beverage bottles. In many embodiments, the bottles are configured for holdi ng liquids. A nonlimiting example of bottles configured for holdi ng l iquid i ncludes beverage bottles having a body that extends between a flat bottom and an upwardly extending neck and opening. Typically such beverage bottles have cylindrically shaped bodies. It wil l be appreciated that the present subject matter can be utilized i n conjunction with a wide array of contai ner configurations and applications, and i n no way is limited to beverage bottles.

[0018] Before turning attention to the label constructions, labeled polymeric containers, and related methods of the present subject matter, it is i nstructive to consider suspected causes of label defects associated with conventional bottl ing practices if dwel l storage is not used.

Causes of Certain Label Defects

[0019] Without wishi ng to be bound to any particular theory, it is believed that many label defects such as bubbles, darts, wrinkles, and the like, result from outgassing of the polymeric material. Many bottles are formed from high density polyethylene (HDPE) which typically exhibits a high degree of outgassing. Gas chromatograph analysis performed by the assignee of the present application, of commercially available HDPE pellets indicate the presence of several al kane gases i n the pellets such as decane, pentadecane, and 9-hexyl heptadecane. After heating and forming of a polymeric container, and particularly one formed from HDPE, alkane gases are emitted along the newly formed container surfaces. Bottles can also be comprised of PET, PP, Vinyl, PLA, and many other plastics as wel l.

[0020] A particular type of labeling defect stems from bubbles that emanate from the bottle side and migrate through the label adhesive toward the label facestock. The bubbles, typical ly comprising various al kane gases, become trapped under the label facestock and thus cause visi ble defects in the adherence of the label to the wall of the bottle. These defects typical ly appear in the label as bubbles, darts, wrinkles, and the li ke. The present subject matter is di rected to preventing or at least reduci ng the occurrence of these defects.

[0021] It wi ll be appreciated however that the present subject matter is not l imited to these types of label defects. Instead, the present subject matter is believed to have wide appl icabil ity to eli mi nate or reduce the potential for other label ing defects or issues.

Label Constructions

[0022] I n one aspect of the present subject matter, label constructions or assemblies are provided that exhibit a particular combination of characteristics. In certain embodiments, the label facestock or fi lm layer(s) is selected so as to exhibit a relatively high oxygen transmission rate and/or a relatively low moisture vapor transmission rate. I n certain embodi ments, the adhesive is selected so as to allow any gases or ai r to permeate through the layer of adhesive. Thus, the adhesive exhi bits a relatively high co-adhesive property, i.e., an affi nity to itself, so that the adhesive can flow back together and close any tunnels or paths that resulted from passage of gas. In certain embodi ments, the label constructions of the present subject matter exhibit all of these characteristics. These aspects are all discussed in greater detail herein.

[0023] I n many embodi ments, the label facestock or fi l m layer exhi bits a particular oxygen transmission rate (OTR) and/or a particular moisture vapor transmission rate ( MVTR). In certain embodiments, the label facestock exhibits a MVTR of from about 0.50 to 2.00 and more particularly from 0.70 to 1.79 g/(m ² per day). The MVTR of the fil ms is measured in accordance with ASTM Method F 1249. I n certai n embodi ments, the label facestock exhibits an OTR of from about 800 to about 1,700, and more particularly from 913 to 1,520 cc/(m ² per day). The oxygen transmission rate of the fil ms is determi ned i n accordance with ASTM Method F 1927. And, in several embodi ments of the present subject matter, the label facestock exhibits a combination of these properties. It wil l be appreciated that the present subject matter includes the use of facestocks exhibiting OTR and/or MVTR values less than or greater than these values. As explained i n greater detail herei n, the label facestock may include multiple layers such as two layers, three layers, or more. I n such embodiments, the col lection, i.e., al l, of the layers should col lectively exhibit these properties of relatively high OTR and/or relatively low MVTR.

[0024] I n many embodiments, the label facestock is formed from polypropylene (PP), polyethylene ( PE), polyethylene terephthalate ( PET), polylactic acid (PLA), polystyrene (PS), polyvinyl chloride (PVC), and combinations of these and potential ly with other materials. Oriented and non- oriented fil ms may be used. For example, for a polypropylene facestock, the PP fil m is typical ly biaxial ly oriented polypropylene (BOPP). In certai n embodiments, the label facestock is formed from commercially available fil ms such as for example FASCLEAR 350 and Crystal Fasclear available from Avery Dennison; RAFLEX Pl us available from UPM Raflatac; Global Coex (GCX) NTC Clear from Avery Dennison; and PE 85 NTC clear from Avery Dennison. These commercial ly available fil ms are blends of polypropylene and polyethylene.

[0025] The label facestock typically has a thickness of from 1.0 mil to 10 mils, and i n certain embodiments a thickness of 1.4 mils to 4 mils. The thickness is typically selected i n view of the label material, end use requi rements, and is not so thick as to impede transmission of oxygen and/or moisture.

[0026] I n certain embodiments, the adhesive, as previously noted, is selected so as to al low any gases or air to permeate through the layer of adhesive and also exhibit a relatively high co-adhesive property, i.e., an affi nity to itself, so that the adhesive can flow back together and close any tunnels or paths that resulted from gas passage. [0027] I n certain embodi ments, the adhesive is an acrylic emulsion adhesive. I n particular embodiments, the adhesive is a permanent acrylic emulsion adhesive. Nonlimiti ng examples of commercially available adhesives include S692N, S730, S1000, S3000, and S490 al l available from Avery Dennison. Another example of a potentially suitable commercially available adhesive is RP75 from UPM Raflatac. The adhesive is typically a pressure sensitive adhesive.

[0028] In particular versions of the present subject matter, the film selected for use in the label constructions exhibits a MD modulus of from about 50,000 to about 300,000 and particularly from about 80,000 to about 225,000 psi. MD Modul us is measured in accordance with ASTM D-882. However, it will be appreciated that the present subject matter i ncl udes the use of adhesives exhi biting modul i val ues less than or greater than these values.

[0029] Adhesive layer thickness or coatweight for the label constructions of the present subject matter depend upon the particular application. However, for many embodi ments, a coatweight of from about 10 to about 40, and more particularly from 18 to 27 g/m ² (also referred to as gsm) can be used. The adhesive can be in the form of a layer of uniform thickness. In certain embodiments, the adhesive could be pattern coated. Adhesive can be appl ied to the facestock or other layer(s) by known techniques such as curtai n coating. Release liners can also be used in the label assembl ies such as glassine or PET liners.

[0030] Additional ly, the adhesive may play a role in the defects. Whi le not wishi ng to be bound by any one theory, it is believed that the emitted gas from the labeled container, when trapped between the labeled contai ner and the label, will form pockets of voids i n the adhesive which can subsequently move, thereby causi ng the visual defects perceived as wrinkles and bubbles. One theory is than an adhesive that flows wil l allow the gas bubble to pass through and not remai n trapped between the labeled bottle and the label, provided the label fil m has sufficient MVTR and OTR to permit the gas to migrate through the fil m. Rheology is the study of adhesive flow, and a particularly useful property is tan delta which for purposes of this appl ication is defi ned as the ratio of viscous modulus (G") to elastic modul us (G') and a useful quantifier of the presence and extent of elasticity or flowabi lity in a fl uid. In particular versions of the subject matter, the adhesive selected has a tan delta value of 0.3-1.9 at 170- 190 C. Additionally or alternatively, the adhesive has a tan delta value from 0.5-3.2 at 140-170 C. The higher val ues of tan delta correspond to an adhesive that flows and helps al leviate the aforementioned defect in combi nation with the right selection of fil m as previously outlined.

Polymeric Contai ner

[0031] The polymeric contai ner or bottle to receive the label constructions of the present subject matter can be formed from a wide range of polymeric materials such as high density polyethylene ( HDPE), polypropylene (PP), polystyrene (PS), ethylene vinyl alcohol ( EVOH), polyethylene terephthalate (PET), polylactic acid (PLA), polyvinyl chloride ( PVC), and nearly any other olefin or plastic blend or coextrusions thereof. In particular applications, HDPE, PP, PET, and blends or multilayer constructions thereof with EVOH can be used. Further, PLA will likely grow in popularity for use in bottles or containers if sustai nability trends continue.

Examples

[0032] A series of investigations were performed to evaluate various label constructions applied to newly molded HDPE bottles, and the extent of label defects occurri ng thereafter.

[0033] Label constructions A-K were prepared and applied to newly molded bottles. The bottles were 6 i nches in height and 2.5 inches i n diameter and formed from Dow HDPE DMDA 6400NT 7 having a melt i ndex of 0.8. The HDPE pel lets were free of additional additives such as antioxidants, antistatic agents, slip agents, and anti block agents. The bottles were flame treated prior to evaluation. The various label constructions were applied to the bottles after 5 minutes from the bottles exiting a mold. The bottle temperature at the ti me of label application was within a range of 83 to 98° F.

[0034] After application of the labels to the bottles, counts of defective labels were made at 1 hour, 4 hours, and 24 hours. Defects were in the form of visible bubbles under the facestock, or the occurrence of any darts or wrinkles in the label facestock.

[0035] Table 1 summarizes the labels, their appl ication parameters, and defects.

Table 1- Summary of Labeling Investigations

[0036] After obtaini ng the results and tabulating the number of labels having defects, several techniques were used to arrive at root cause and conclusions. Due to multiple properties and fil ms employed, a best subsets analysis was used to extract conclusions as to what factors led to a successful label. Various fil ms were used with a fixed adhesive, S692N, at a fixed coatweight. With this analysis of common factors (modul us, stiffness, tear, MVTR, and OTR) a predictive equation was found that had an R-squared value of 93.3%. Additionally, with further analysis, standard statistical diagnostic tools such as normal probability plot, histogram, fits, and order did not detect any issues that would i ndicate the data could be skewed or i nterpretations would be suspect. With the above analysis, the following fresh bottle label predictive equation of fil m properties was derived. This equation is periodically referred to herein as equation ( I).

Percentage Pass = 1.33 - 0.000006 ( MD Modul us) - 0.785 ( MVTR) + 0.000686 (OTR)

[0037] Equation ( I) provides a prediction as to the percentage pass for label constructions based upon (i) the MD modul us of the adhesive, (ii) the MVTR of the facestock, and (iii) the OTR of the facestock. Using equation ( I), for a label construction having characteristics (i) - (iii) which lead to a 100% pass, means that no label defects are predicted. Equation (I) was obtai ned as a li near regression analysis i n Ml N ITAB Software available from Mi nitab, Inc.

[0038] While one of ordinary skill in the art would have expected that a fi l m havi ng a relatively lower modulus would demonstrate fewer defective labels as compared to the number of defective labels made from a fil m having a relatively higher modul us. It is general ly understood that a fil m with a lower modulus is more conformable than a fil m with a higher modul us, and accordi ngly, the lower modul us ( more conformable) fil m would be expected to conform to the shape of the labeled bottle and accordingly demonstrate fewer defects. As shown i n example K, the lowest modulus (83,000 psi) fil m PE 85 is listed. However, in example F (Crystal Fasclear at 115,000 psi modul us) and example B ( Fasclear 350 at 130,000 psi modulus), the results don't align with the expectation that a lower modul us fil m would demonstrate fewer defective labels as compared to a higher modulus fil m. In fact, example E ( Fasclear 350 fi lm and a different adhesive, S1000), the results are similar to those exhibited by example K. This comparison demonstrates that the modul us is not the sole determining factor for label defects in the i nstant tests, and i nstead that at least the combi nation of the adhesive properties and the film properties influence defective labels. This data aligns with the formula from above, and thus contravenes what would be expected by one of ordi nary skill i n the art, that the lower the modulus of the fi l m, the better fresh bottle label performance. Such data is also consistent with the new understanding that selecti ng a film which allows gas to escape at rate that is the same or higher than the rate at which the bottle or other substrate emits gas at the bottle-adhesive interface results i n relative fewer defects than a configuration where the gas emission rate of the bottle is greater than the gas emission rate of the film.

[0039] Accordi ngly, the problem that has traditionally been identified i n relation to labeling of fresh bottles, that the standard combi nation of fil m and adhesive must be more conformable to the bottle to el imi nate label defects, has not proven to be the source of label defects. Here, the problem has actual ly been entrapment of gas emitted by the bottle between the label and the bottle, and the solution to this problem, rather than providing a more conformable fil m, has been to provide a fi lm having an MVTR which is greater than the rate at which the bottle is emitting gas in combination with an adhesive demonstrating rheological properties which permit gas to flow through the adhesive and transfer through the fil m, while the adhesive still flows back upon the path of the gas so as not to provide any observable trail of entrained gas. [0040] An example of applying equation ( I) is as fol lows usi ng a label construction of a 2 mil clear biaxial ly oriented polypropylene ( BOPP) facestock within a layer of S692N adhesive. The modul us of that fil m is 225,000 psi, the MVTR of the facestock is 0.69 g/(m ² per day), and the OTR of the facestock is 994 cc/( m ² per day). Using these values in equation ( I) results in a predicted pass rate of 0.12 or 12%. This is consistent with the data obtained i n Table 1 (see Label Construction A). Although a predicted pass rate of 12% is l ikely unacceptable to i ndustry, it is believed that for certain applications a BOPP facestock could be used if other aspects were modified. For example, selecting a thi nner BOPP facestock and using a fi lm exhibiti ng a different MD modulus could lead to a higher predicted label pass rate.

Methods

[0041] The present subject matter also provides methods of labeling plastic contai ners in which the resulti ng labeled containers exhi bit a relatively low label defect rate. The methods general ly comprise selecting a suitable label construction, and applyi ng the label construction to a container and typical ly to a newly produced plastic contai ner. The label incl udes at least one film layer and a layer of an adhesive. The label is applied to a plastic contai ner by contacti ng and/or adheri ng the adhesive layer to the container. Typically, the adhesive is contacted with an outer surface of the contai ner. The methods may also include other processing operations or steps typically employed in the plastic contai ner and/or label ing i ndustries.

[0042] The label constructions that can be used are selected such that the label facestock exhibits at least one of the previously noted OTR and MVTR values. I n certai n embodi ments, the label constructions are selected such that the label facestock exhi bits both of the previously noted OTR and MVTR values. And, in particular embodi ments, the label constructions are selected such that the adhesive used i n the label constructions exhibits the previously noted modulus values. And, i n sti ll other embodiments, the label constructions are selected such that the label facestock exhibits one or both of the noted OTR and MVTR val ues in combi nation with the adhesive exhi biting the noted modulus values.

[0043] Selection of the label construction can be performed by using equation ( I) as a guide to selecting facestock and adhesive materials. Equation ( I) provides an esti mate of the percentage of applied labels that are free of label ing defects after label application, based upon the noted properties of the facestock and the adhesive.

[0044] The methods also involve applying selected label constructions to a plastic contai ner. As described herei n, i n accordance with the present subject matter, selected label constructions can be applied to plastic containers that are newly manufactured. I n many embodi ments of the present subject matter, the labels can be applied withi n 15 mi nutes, more particularly withi n 10 mi nutes, and more particularly within 5 mi nutes of a contai ner's manufacture, i.e., moldi ng. Typically, for HDPE bottles which are typically molded at a temperature of about 265° F, the label construction can be applied to the newly manufactured bottle within 15 minutes after moldi ng and when the temperature of the bottle is from about 75 ° F to 125° F. Application of the selected label construction to the container or bottle of i nterest can be performed by any suitable labeli ng technique. A wide variety of conventional label ing techniques and equi pment are commercially available. However, it will be appreciated that the present subject matter is not limited to any of these techniques or practices. I nstead, the present subject matter wil l have a wide array of appl ications and variant aspects.

[0045] The present subject matter also provides methods of reduci ng the occurrence of label defects. These methods involve selecting particular combinations of properties for facestocks and/or adhesive used in the label assembly by use of equation ( I) noted herein. That is, if a particular label pass rate percentage is desired, such as 95%, the facestock is selected and/or the adhesive is selected, or both of these components are selected such that equation (I) equals 0.95 or greater, i.e., 0.98. Alternatively, for a known label construction having a known facestock OTR, a known facestock MVTR, and a known adhesive MD modulus, those values can be used in equation ( I) to arrive at a predicted label pass rate. Then, using equation (I), consideration can be made as to changes i n the facestock OTR, facestock MVTR, and/or adhesive MD modul us that result in an increase in the predicted label pass rate.

[0046] The present subject matter also provides methods of eli mi nati ng a need for bottle dwell storage or at least reducing the time periods associated with such storage. These methods i nvolve selecti ng particular combi nations of properties for facestocks and/or adhesive used in the label assembly by use of equation (I) noted herei n. Thus, for a known label construction having a known facestock OTR, a known facestock MVTR, and a known adhesive MD modulus; equation ( I) can be used to evaluate the particular OTR, MVTR, and/or modulus values and whether those val ues should be i ncreased or decreased i n order to i ncrease the predicted label pass rate, and in certain appl ications maxi mize the label pass rate.

Representative Embodiments

[0047] Figure 1 is a schematic cross sectional view of an embodi ment of a label construction in accordance with the present subject matter. The label construction 10 comprises one or more label facestock (or face) layers, collectively designated as 20, and a layer or region of an adhesive shown as 30. The outer surface of the facestock is shown as 22 and depending upon end use, may receive one or more material layers or coati ngs thereon. The adhesive layer 30 defines an adhesive face 32 that contacts a receivi ng surface or substrate such as a polymeric container.

[0048] Figure 2 is a schematic cross sectional view of the label construction of Figure 1 adhered to a polymeric substrate 80. Figure 2 shows a system 100 of a labeled substrate. The substrate 80 may be i n the form of a wall of a container such as a plastic bottle sidewalk The sidewall defines an i nner face 82, which defines an interior region of the bottle. [0049] Figure 3 is a schematic perspective view of a labeled container 150 i n accordance with the present subject matte r. The labeled contai ner 150 comprises a label construction 110 as described herei n that is adhered to a contai ner or bottle 180.

[0050] Many other benefits will no doubt become apparent from future application and development of this technology.

[0051] All patents, published applications, and articles noted herei n are hereby incorporated by reference in thei r entirety.

[0052] As described hereinabove, the present subject matter solves many problems associated with previous strategies, systems and/or devices. However, it wi ll be appreciated that various changes in the details, materials and arrangements of components, which have been herein descri bed and i ll ustrated i n order to explain the nature of the present subject matter, may be made by those skil led in the art without departing from the pri nciple and scope of the claimed subject matter, as expressed i n the appended claims.