Shrink wrap labels for shaped articles

Abstract

Methods for applying high shrink wrap labels to a shaped article are disclosed. The leading edge of the label is bonded to the article. A seaming agent is applied, and the label is wrapped around the article. The seaming agent is then exposed to radiation to cure the seaming agent, and the label is then exposed to heat to cause heat-shrinking. The label is made of a film with at least one external layer that has a Hildebrand solubility parameter. The seaming agent includes a component having a Hildebrand solubility parameter that is within 2.2 MPa1/2 or within 4.4 calories1/2·cm−3/2 of the Hildebrand solubility parameter of the external layer of the film. The seaming agent also has a viscosity of at least 1 centipoise and less than 1000 centipoise when measured at any temperature between ambient temperature and 60° C. Articles including such affixed high shrink wrap labels are also disclosed.

1 . A method for applying a high shrink wrap label film to a shaped article, comprising:
 bonding a leading edge of the high shrink wrap label film to the shaped article;   applying a liquid seaming agent to the leading edge of the high shrink wrap label film or to a trailing edge of the high shrink wrap label film;   wrapping the high shrink wrap label film around the shaped article until the trailing edge contacts the leading edge;   creating a seam that joins the trailing edge of the high shrink wrap label film to the leading edge of the high shrink wrap label film with the seaming agent; and   exposing the seam to radiation to cure the seaming agent;   wherein the liquid seaming agent has at least one component with a Hildebrand solubility parameter that is within 2.2 MPa 1/2  or within 4.4 calories 1/2 ·cm −3/2  of a Hildebrand solubility parameter of an external layer of the high shrink wrap label film.   
     
     
         2 . The method of  claim 1 , further comprising heat shrinking the high shrink wrap label film after the seaming agent is cured. 
     
     
         3 . The method of  claim 1 , wherein the seam is exposed to radiation within 1 second of creating the seam; or
 wherein the high shrink wrap label film is applied to the shaped article on a roll-fed machine; or   wherein the high shrink wrap label film is applied to the shaped article on the roll-fed machine at a speed of 200 shaped articles per minute or greater; or   wherein the seaming agent has a viscosity of at least 1 centipoise and less than 100 centipoise when measured at any temperature between ambient temperature and 60° C.   
     
     
         4 . The method of  claim 1 , wherein:
 the high shrink wrap label film contains polystyrene (PS), polyethylene terephthalate glycol-modified (PETG), or polyvinyl chloride (PVC); and   the seaming agent comprises at least one monomer which is tetrahydrofurfuryl acrylate (THFA) or caprolactone-modified THFA; cyclic trimethylol propane formal acrylate (CTFA); isobornyl acrylate; isobornyl methacrylate; alkoxylated phenyl acrylate; hexanediol diacrylate; butanediol diacrylate; butanediol dimethacrylates; alkoxylated aliphatic or cycloaliphatic diol diacrylate or dimethacrylate; tricyclodecanedimethanol diacrylate (TCDDA); ethoxylated cyclohexane dimethanol diacrylate (EO-CHMDA); hydroxy pivalic acid neopentyl glycol diacrylate or caprolactone-modified hydroxy pivalic acid neopentyl glycol diacrylate, hydroxypyvalyl pivalate diacrylate (HPPDA), or caprolactone acrylate.   
     
     
         5 . The method of  claim 1 , wherein:
 the high shrink wrap label film contains a polyolefin or a cyclic olefin polymer (COP) or a cyclic olefin copolymer (COC); and   the seaming agent comprises at least one monomer which is isobornyl acrylate, isobornyl methacrylate, cyclohexyl acrylate, ethyl hexyl acrylate, ethyl hexyl methacrylate, tert-butyl cyclohexyl acrylate, trimethyl cyclohexyl acrylate, alkyl acrylates, alkyl methacrylates, tricyclodecanedimethanol acrylate, styrene, vinyltoluene, benzyl acrylate, lauryl acrylate, isodecyl acrylate, phenoxy benzyl acrylate, ethoxylated aryl acrylate, alkylated phenyl acrylate, or phenyl acrylate.   
     
     
         6 . The method of  claim 1 , wherein the seaming agent comprises:
 from 25 wt % to 98 wt % of a monomer having a molecular weight of 300 daltons (Da) or less;   from 0 to 70 wt % of an organic solvent having a molecular weight of 300 daltons (Da) or less;   from 0 wt % to 80 wt % of an oligomer or polymer having a molecular weight of 300 daltons (Da) or greater; and   from 0.5 wt % to 15 wt % of a photoinitiator;   wherein the monomer or the organic solvent has the Hildebrand solubility parameter that is within 2.2 MPa 1/2  or within 4.4 calories 1/2 ·cm −3/2  of the Hildebrand solubility parameter of the external layer of the high shrink wrap label film.   
     
     
         7 . The seaming agent of  claim 1 , containing:
 from 40 wt % to 60 wt % of monomers having a molecular weight of 300 daltons (Da) or less;   from 10 to 30 wt % of the organic solvent having a molecular weight of 300 daltons (Da) or less;   from 0 wt % to 15 wt % of oligomers or polymers having a molecular weight of 300 daltons (Da) or greater;   from 0.5 wt % to 15 wt % of the photoinitiator; and   from 15 to 25 wt % of a tackifying agent.   
     
     
         8 . The method of  claim 1 , wherein the seaming agent comprises:
 from about 20 wt % to about 99 wt % of an acrylic or methacrylic acid ester or amide or carbamate having a molecular weight lower than 300 daltons (Da);   0 to about 50 wt % of an acrylic or methacrylic acid ester or amide or carbamate having a molecular weight greater than 300 daltons (Da);   0 to about 40 wt % of a tackifying agent or polymer;   0 to about 50 wt % of an organic solvent;   a photoinitiator;   optionally, an adhesion promoter.   
     
     
         9 . The method of  claim 1 , wherein the high shrink wrap label film comprises a polyolefin; and
 the seaming agent comprises an acrylic or methacrylic acid ester or amide or carbamate containing a cyclic hydrocarbon group; an acrylic or methacrylic acid ester or amide or carbamate containing a hydrocarbon having a maximum of 20 carbon atoms; or an acrylic or methacrylic acid ester or amide or carbamate containing an aromatic hydrocarbon or heterocyclic group having a maximum of 20 carbon atoms.   
     
     
         10 . The method of  claim 1 , wherein the high shrink wrap film comprises at least one layer comprising a cyclic olefin polymer or a cyclic olefin copolymer. 
     
     
         11 . The method of  claim 10 , wherein the seaming agent comprises a monomer having a molecular weight of less than 300 Da selected from the group consisting of isobornyl acrylate, isobornyl methacrylate, cyclohexyl acrylate, ethyl hexyl acrylate, ethyl hexyl methacrylate, tert-butyl cyclohexyl acrylate, trimethyl cyclohexyl acrylate, alkyl acrylates, alkyl methacrylates, tricyclodecanedimethanol acrylate, styrene, vinyltoluene, benzyl acrylate, lauryl acrylate, isodecyl acrylate, phenoxy benzyl acrylate, ethoxylated aryl acrylate, alkylated phenyl acrylate, and phenyl acrylate. 
     
     
         12 . The method of  claim 10 , wherein the seaming agent comprises an oligomer or polymer having a molecular weight of more than 300 Da selected from the group consisting of urethane acrylate, urethane methacrylate, acrylic or methacrylic esters of glycols or diols or polyhydric alcohols, acrylic or methacrylic esters of alkoxylated diols or polyols or polyhydric alcohols, oligomers of acrylic or methacrylic esters, polyvinylbutyral, hydrocarbon resins, polyterpenes, rosin derivatives, polyesters, polystyrene, styrene block copolymers, epoxy acrylates, epoxy methacrylates, phenoxy resins, acrylated or methacrylated dendritic alcohols, ethoxylated diglycidyl ether of bisphenol A diacrylate; polyacrylates of hyperbranched alcohols; blends of urethane acrylate and monomer; and (T) blends of inert resin and monomer. 
     
     
         13 . The method of  claim 10 , wherein the seaming agent comprises a solvent selected from the group consisting of a linear or cyclic or aromatic hydrocarbon having a maximum of 20 carbon atoms, a terpene alcohol, an alkyl ester, an alkyl amide, turpentines, isoparaffins, and paraffins. 
     
     
         14 . The method of  claim 10 , wherein the seaming agent comprises:
 from about 25 wt % to about 98 wt % of a monomer;   from 0 wt % to about 50 wt % of an oligomer or polymer;   from 0 to about 50 wt % of an organic solvent; and   from about 0.5 wt % to about 15 wt % of a photoinitiator.   
     
     
         15 . The method of  claim 1 , wherein the high shrink wrap film comprises at least one layer containing polystyrene (PS), polyethylene terephthalate glycol-modified (PETG), or polyvinyl chloride (PVC), or a blend thereof. 
     
     
         16 . The method of  claim 15 , wherein the seaming agent comprises a monomer having a molecular weight of less than 300 Da that is (a) an acrylic or methacrylic ester, amide, or carbamate having a cyclic ether containing group, such as tetrahydrofurfuryl or dioxane; or (b) an acrylic or methacrylic ester, amide, or carbamate having an ethoxylated or propoxylated aromatic or cycloaliphatic group; (c) an alkyl diol or polyol diacrylate or dimethacrylate; (d) a vinyl lactam; (e) an acrylamide or methacrylamide; (f) vinyl pyrrolidone or a nitrogen heterocyclic unsaturated monomer; (g) a vinyl morpholine; (h) a lactone or lactam having an acrylate, methacrylate, or vinyl group; (i) a phenyl or alkyl phenol acrylate or methacrylate; (j) an ethoxylated or propoxylated phenyl or alkyl phenol acrylate or methacrylate; (k) a mono- or di- or tri-hydroxyl acid acrylate or methacrylate; (l) an urethane acrylate or methacrylate; (m) an allyl ether; (n) a vinyl ester; (o) a mono-, di-, tri-, tetra-, or poly-acrylate or -methacrylate of a polyhydric alcohol, including an ethoxylated or propoxylated polyhydric alcohol; or (p) 2-(2-ethoxyethoxy)ethyl acrylate. 
     
     
         17 . The method of  claim 15 , wherein the seaming agent comprises an oligomer or polymer selected from the group consisting of urethane acrylate, urethane methacrylate, acrylic or methacrylic esters of glycols or diols or polyhydric alcohols, acrylic or methacrylic esters of alkoxylated diols or polyols or polyhydric alcohols, oligomers of acrylic esters, polyvinylbutyral, hydrocarbon resins, polyterpenes, rosin derivatives, polyesters, epoxy resins, epoxy acrylates, epoxy methacrylates, phenoxy resins, a resin containing a diglycidyl ether of bisphenol-A, polystyrene, styrene block copolymers or terpolymers, terpene phenols, polyester acrylates or methacrylates, polyurethane, polyesteramide, oligomers of acrylic or methacrylic acids or esters or amides; homopolymers, copolymers, terpolymers, or block copolymers of an acrylic acid ester or methacrylic ester; ethoxylated diglycidyl ether of bisphenol A diacrylate; polyacrylates of hyperbranched alcohols; blends of urethane acrylate and monomer; and blends of inert resin and monomer. 
     
     
         18 . The method of  claim 15 , wherein the seaming agent comprises a solvent selected from the group consisting of ethers, cyclic ethers, esters, amides, glycol ethers, ketones, toluene, halogenated alcohols, and halogenated hydrocarbons. 
     
     
         19 . The method of  claim 15 , wherein the seaming agent comprises:
 from about 25 wt % to about 98 wt % of a monomer;   from 0 wt % to about 75 wt % of an oligomer or polymer;   0 to about 50 wt % of an organic solvent; and   from about 0.5 wt % to about 15 wt % of a photoinitiator.   
     
     
         20 . The method of  claim 1 , wherein when the % VOC of the seaming agent is measured per the modified method of Example 5, the % VOC of the seaming agent is about 30% to about 50% of the amount of the organic solvent in the seaming agent; or
 wherein the seaming agent has the ability to cross-link or polymerize when exposed to radiation having at least one peak wavelength of about 300 nm to about 500 nm; or   wherein the seaming agent has a flashpoint of about 65° C. or greater.   
     
     
         21 . A shaped article with a high shrink wrap label applied according to  claim 1 . 
     
     
         22 . A system for forming a welded seam, comprising:
 a high shrink wrap label made of a film having an external layer with a Hildebrand solubility parameter; and   a seaming agent including a component having a Hildebrand solubility parameter that is within 2.2 MPa 1/2  or within 4.4 calories 1/2 ·cm −3/2  of the Hildebrand solubility parameter of the external layer of the film, and having a viscosity of at least 1 centipoise and less than 1000 centipoise when measured at any temperature between ambient temperature and about 60° C.   
     
     
         23 . A welded seam formed from two edges of a film and a seaming agent, wherein when:
 (1) the film of the seam is cleaned to remove any ink or coating, and the two edges are separated from each other;   (2) the film and the seam are dried to remove volatiles;   (3) the seam is heated to a temperature of 200° C. to obtain a gas phase derived from the seam; and   (4) the gas phase derived from the seam is collected and analyzed,   the gas phase derived from the seam comprises at least three different signature molecules that each (A) have a molecular weight of 230 Da or less, (B) have an aliphatic alkane or alkene backbone containing at least three carbon atoms, (C) contain only one or two acid groups, only one or two ester groups, only one aldehyde group, or only one epoxide group, and (D) do not contain any aromatic, cyclic, or heterocyclic groups.   
     
     
         24 . The welded seam of  claim 23 , wherein:
 (A) at least one of the at least three different signature molecules contains an acrylate group, or is a fatty acid alkyl ester, or is an alkyl aldehyde; or   (B) wherein a piece of the film which is not a part of the welded seam is also cleaned to remove any ink or coating; dried to remove volatiles; then heated to a temperature of 200° C. to obtain a gas phase derived from the film; and the gas phase derived from the film is collected and analyzed; and the signal derived from the film is subtracted from a signal derived from the seam to further identify the at least three different signature molecules.