CN104010816B - Multilayered shrink films - Google Patents

Abstract

Multilayered shrink films comprises: at least three layers, including two top layers and at least one core layer；At least one of which layer comprises the unit deriving from one or more polymer compositions based on ethylene of 10wt% to 100wt%, described polymer composition based on ethylene is characterised by that comonomer distribution constant is 75 to 220, and vinyl degree of unsaturation is the carbon atom that 30 to 100 vinyls each million are present in the main chain of polymer composition based on ethylene；Zero-shear viscosity ratio (ZSVR) is at least 2.5 to 15；Density is 0.924g/cm³To 0.940g/cm³, melt index (MI) (I₂) it is 0.1g/10min to 1g/10min, molecular weight distribution (Mw/Mn) is 2.5 to 10, and molecular weight distribution (Mz/Mw) is 1.5 to 4；Wherein multilayer film demonstrates that at least one is selected from the characteristic of following properties: 45 degree of glossiness of at least 50%, total mist degree of 15% or less, the internal haze of 8% or less, 43, the 1%CD secant modulus of 000psi or bigger, the CD shrink tension of the 1%MD secant modulus of 38,000psi or bigger, at least 0.7psi and/or the MD shrink tension of at least 10psi.

Description

Multilayered shrink films

Technical field

The present invention relates to multilayered shrink films.

Technical background

For shrink film, minimizing (Downgauging) is a trend, in order to reduce cost and material Consume.But, in order to reduce the thickness of shrink film, membrane material must keep high rigidity, to guarantee packaging Speed and feel.Additionally, for consumer's impression and market place differentiation, need shrink film to have excellence Optical property and transparency.At present, by with film transparency for cost by high density polyethylene (HDPE) (HDPE) Component is included in film based on LDPE, improves the hardness of film.Generally, by utilizing high-pressure free radical Film prepared by the Regular low density polyethylene (LDPE) of chemistry is also used due to their high convergency characteristic. But, LDPE film has low modulus, thus limits the ability of minimizing.

Summary of the invention

The present invention is shrink film.In one embodiment, the invention provides multilayered shrink films, its bag Contain: at least three layers, including two top layers and at least one core layer；At least one of which layer comprises 10wt% To the unit deriving from one or more polymer compositions based on ethylene of 100wt%, described based on second The polymer composition of alkene is characterised by comonomer distribution constant (Comonomer Distribution Constant) (CDC) is 75 to 220, and vinyl degree of unsaturation is 30 to 100 vinyls each hundred Carbon atom in ten thousand main chains being present in polymer composition based on ethylene；Zero-shear viscosity ratio (ZSVR) it is at least 2.5 to 15；Density is 0.924g/cm³To 0.940g/cm³, melt index (MI) (I₂) it is 0.1g/10min to 1g/10min, molecular weight distribution (Mw/Mn) is 2.5 to 10, molecular weight distribution (Mz/Mw) it is 1.5 to 4；Wherein multilayer film demonstrates that at least one is selected from the characteristic of following properties: extremely 45 degree of glossiness of few 50%, total mist degree of 15% or less, the internal haze of 8% or less, 43,000 The 1%CD secant modulus of psi or bigger, the 1%MD secant modulus of 38,000psi or bigger, at least The CD shrink tension of 0.7psi and/or the MD shrink tension of at least 10psi.

Accompanying drawing explanation

In order to the present invention is described, it is shown that exemplary accompanying drawing；It is to be understood, however, that the present invention does not limits Accurately arrange and means in shown.

Fig. 1 is complex viscosity data and the frequency of the dynamic mechanical spectra of present composition embodiment 1-4 Relation；

Fig. 2 is the tan δ data pass with frequency of the dynamic mechanical spectra of present composition embodiment 1-4 System；

Fig. 3 is phase angle and the complex modulus relation of present composition embodiment 1-4 The dynamic mechanical spectrogram of (Van-GurpPalmen figure)；

Fig. 4 be present composition embodiment 1-4 at the melt strength data of 190 DEG C；

Fig. 5 is the conventional GPC figure of present composition embodiment 1-4；With

Fig. 6 is the CEF figure of present composition embodiment 1-4.

The present invention illustrates

The present invention is multilayered shrink films.The multilayered shrink films of the present invention comprises: at least three layers, including two Top layer and at least one core layer；At least one of which layer comprise 10wt% to 100wt% derive from based on The unit of the polymer composition of ethylene, described polymer composition based on ethylene comprises: (a) less than or The unit deriving from ethylene equal to 100wt%；(b) be less than 30wt% derives from one or more α-alkene The unit of hydrocarbon comonomer；Wherein said polymer composition based on ethylene is characterised by that CDC is 75 to 220, vinyl degree of unsaturation is that 30 to 100 vinyls each million are present in based on second Carbon atom in the main chain of the polymer composition of alkene；ZSVR is at least 2.5 to 15；Density is 0.924 g/cm³To 0.940g/cm³, melt index (MI) (I₂) it is 0.1g/10min to 1g/10min, molecular weight distribution (Mw/Mn) being 2.5 to 10, molecular weight distribution (Mz/Mw) is 1.5 to 4；Wherein multilayer film demonstrates At least one is selected from the characteristic of following properties: 45 degree of glossiness of at least 50%, 15% or less total Mist degree, the internal haze of 8% or less, the 1%CD secant modulus of 43,000psi or bigger, 38,000 The CD shrink tension of the 1%MD secant modulus of psi or bigger, at least 0.7psi and/or at least 10psi MD shrink tension.

The multilayered shrink films of the present invention comprises: at least three layers, including two top layers and at least one core layer； At least one of which layer comprises the polymer composition of based on ethylene of deriving from of 10wt% to 100wt% Unit.The application includes and discloses all single value and the subinterval of 10wt% to 100wt%.Example As, the unit of what at least one layer comprised derive from polymer composition based on ethylene can from 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, 80wt% or 90wt%'s Lower limit to 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, 90 The upper limit of wt% or 100wt%.Such as, at least one layer derives from combination of polymers based on ethylene The amount of the unit of thing can be 10wt% to 100wt% or 20wt% to 65wt% or 30wt% extremely 70wt%.

Polymer composition based on ethylene comprises (a) less equal than 100wt% (such as, at least 70 Wt% or at least 80wt% or at least 90wt%) the unit deriving from ethylene；(b) less than 30 Wt% (such as less than 25wt% or less than 20wt% or less than 10wt%) derive from one or more α- The unit of olefin comonomer.Term " polymer composition based on ethylene " refers to rub containing having more than 50 The vinyl monomer (total amount based on polymerisable monomer) of the polymerization of your percent and optionally can containing extremely The polymer of few a kind of comonomer.Alpha-olefin comonomer is generally of less than 20 carbon atoms. For example, it is preferable that alpha-olefin comonomer can have 3 to 10 carbon atoms, more preferably tool There are 3 to 8 carbon atoms.Exemplary alpha-olefin comonomer includes but not limited to propylene, 1-butylene, 1- Amylene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene and 4-methyl-1-pentene.Such as, One or more alpha-olefin comonomer can be selected from propylene, 1-butylene, 1-hexene and 1-octene；Or Alternatively, it can be selected from 1-hexene and 1-octene.

In another embodiment, for each million parts of polymer compositions based on ethylene, based on second The polymer composition of alkene comprise less equal than 100 weight portions (such as less than 10 weight portions, less than 8 Weight portion, less than 5 weight portions, less than 4 weight portions, less than 1 weight portion, less than 0.5 weight portion or Less than 0.1 weight portion) metal complex residue (it is by the metal complex comprising multivalence aryloxy group ether Catalyst system institute remaining).Can be measured in polymerization based on ethylene by x-ray fluorescence (XRF) By the metal that the catalyst system of the metal complex comprising multivalence aryloxy group ether is remaining in compositions Coordination compound residue, uses reference standard correction x-ray fluorescence.In a preferred method, can rise Combination of polymers composition granule is compression molded into thickness and is about the print of 3/8 inch, for x-ray by high temperature Test.In the case of very low concentration of metal complex (as less than 0.1ppm), ICP-AES (electricity Sense coupled plasma-atomic emission spectrometry) measure to be present in polymer composition based on ethylene by being In the appropriate method of metal complex residue.

Polymer composition based on ethylene can also comprise other component, and such as one or more, other gathers Compound and/or one or more additives.This additive include but not limited to antistatic additive, toner, Dyestuff, lubricant, filler, pigment, main anti-oxidant, auxiliary antioxidant, processing aid, UV Stabilizer, antiblocking agent, slip agent, viscosifier, fire retardant, antimicrobial, eliminating smell agent (odor reducer Agents), antifungal and combinations thereof.Polymer composition based on ethylene can be containing about 0.1 This total additive of wt% to 10wt%, based on the combination of polymers based on ethylene including this additive The weight of thing.

In one embodiment, the comonomer distribution curve of polymer composition based on ethylene exists The temperature range of 35 DEG C to 120 DEG C comprises Unimodal Distribution or bimodal distribution (not including flushing part).

The ethylene (co) polymerization reaction method that can use any routine prepares polymer based on ethylene Compositions.The ethylene (co) polymerization reaction method of this routine includes but not limited to use one or more conventional Reactor (such as annular-pipe reactor, stirred-tank reactor, batch reactor, with series and parallel and/or it Any combination of mode) slurry phase polymerisation process, solution-phase polymerisation process and combinations thereof.

In one embodiment, by the method preparation polymer based on ethylene comprised the steps of: A () makes ethylene and one or more optional alpha-olefins be polymerized in the presence of the first catalyst system, from And formed hemicrystalline based on ethylene in the first reactor or in the Part I of many parts reactor Polymer；(b) ethylene and one or more optional alpha-olefins of making fresh offer are comprising organic gold In the presence of second catalyst system of metal catalyst react, thus at least one other reactor or Polymer composition based on ethylene is formed, wherein in step (a) in the rear portion of many parts reactor Or at least one in the catalyst system in (b) comprises the metal of the multivalence aryloxy group ether corresponding to following formula Coordination compound:

Wherein M³It is Ti, Hf or Zr, preferably Zr；Ar⁴Independently be substituted when occurring every time C_9-20Aryl, wherein said substituent group when occurring every time independently selected from alkyl, cycloalkyl, and aryl, And halo, trihydrocarbylsilyl groups replace and the substituted derivant of halohydrocarbyl, condition is at least one The aryl that substituent group is connected with it is the most coplanar；T⁴C is independently be when occurring every time_2-20Alkylidene, Ring alkylidene or ring alkenylene or the substituted derivant of its inertia；R²¹Independently be when occurring every time Hydrogen, halogen, it is not counted in two (alkyl) amino that hydrogen comprises at most 50 atoms interior, alkyl, trialkyl Silicyl, trihydrocarbylsilyl groups alkyl or alkoxyl；R³Independently be hydrogen, halogen when occurring every time Element, be not counted in hydrogen interior comprise at most the amino of 50 atoms, alkyl, trihydrocarbylsilyl groups, three Hy drocarbylsilyl alkyl or alkoxyl, or two R on identical arlydene ring³Group is altogether With the R formed or on identical or different arlydene ring³And R²¹Group is collectively forming two positions It is connected to described arlydene or the divalent ligand group connected together by the arlydene ring that two different；R^D Independently be halogen every time when occurring or be not counted in hydrogen at the interior alkyl comprising at most 20 atoms or three hydrocarbon Base silicyl, or 2 R^DGroup be jointly alkylene (hydrocarbylene), hydrocarbon diyl, two Alkene or many (alkyl) silicylene.

Polymer based on ethylene can be prepared by solution polymerization according to following illustrative methods Compositions.By (commercially available with trade name Isopar E to all of raw material (ethylene, 1-octene) and process solvent High-purity isoparaffic solvent from the narrow boiling spread of ExxonMobil Corporation) pure with molecular sieve Change, be then incorporated in reaction environment.Hydrogen provides as high purity grades in the gas cylinder of pressurization, no Make further purification.Reactor monomer feed (ethylene) flows through mechanical compressor and is pressurized to higher than reaction pressure The pressure (about 750psig) of power.Solvent and comonomer (1-octene) charging are pressurized to height through machinery constant volume pump Pressure (about 750psig) in reaction pressure.The solvent (Isopar E) that can use purification will individually be urged Agent component is diluted to the concentration of component specified the most in batches, is forced into the pressure higher than reaction pressure Power (about 750psig).All of reaction feed stream can use mass flowmenter to measure, and uses meter The valve control system of Suan Ji automatization carries out independent control.The continuous solution polymerization reactor system of the present invention System can by two the full liquid (liquid full) operated with cascaded structure, nonadiabatic, constant temperature, circulation, With the independent loop controlled composition.Each reactor to all of fresh solvent, monomer, comonomer, hydrogen, With catalytic component charging, there is independent control.By making feed stream pass heat exchanger, will be delivered to each The temperature of the solvent of the merging of reactor, monomer, comonomer and hydrogen charging is independently controlled in 5 DEG C To 50 DEG C, it is normally controlled in 40 DEG C.The fresh copolymerization list being delivered to polymer reactor can be manually adjusted Body feeds, comonomer is added in one of following three kinds of selections: the first reactor, and the second reaction Device, or common solvent, then according to the ratio of solvent feed shunting is distributed between two reactors. Total fresh feed two position injecting reactors at each reactor of each polymer reactor will be delivered to In, substantially there is between each injection phase equal reactor volume.Each syringe is generally used to control Fresh feed, receives the half of total fresh feed quality stream.By catalytic component by custom-designed note Penetrate pin and inject in polymer reactor, by relative position identical in its independently of one another injecting reactor, its In before injecting reactor, be not in contact with the time.Computer controls main catalyst component charging, so that instead Device monomer concentration is answered to be maintained at the target specified.Based on the appointment mole with main catalyst component calculated Ratio, feeds two cocatalyst component.After each fresh injection position (charging or catalyst) at once Static mixing device is used feed stream to be mixed with the polymer reactor content of circulation.Make each reaction The content of device is continuously circulated through the heat exchanger being responsible for removing major part reaction heat, and the cooling of heat exchanger The temperature of agent side is responsible for the reaction environment of constant temperature is maintained at the temperature specified.It is provided about by screw pump The circulation of each reactor loop.From the effluent of the first polymer reactor (containing solvent, monomer, copolymerization Monomer, hydrogen, catalytic component and melted polymer) leave the first reactor loop, through controlling Valve (is responsible for making the pressure of the first reactor be maintained at the target specified), is injected into the of similar designs In dimerization reactor.When stream leaves reactor so that it is contact to terminate anti-with deactivator (such as water) Should.Additionally, various additives (such as antioxidant) can add at this point.Then, stream is through another One group of static mixing device, to be uniformly dispersed catalysqt deactivation agent and additive.Add additive it After, effluent (containing solvent, monomer, comonomer, hydrogen, catalytic component and melted polymer) Through heat exchanger, thus improve the temperature of stream, for polymer and other more lower boiling reactive component Separation is prepared.Subsequently this stream enter two-stage separate and devolatilization system, wherein from solvent, hydrogen, Unreacted monomer and comonomer remove polymer.Stream at recirculation be again introduced into reactor it The stream of front purification recirculation.Polymer melt after pumping separation and devolatilization is through special for granulation underwater The die head of design, is cut into uniform solid grain, is dried, transfers them in charging hopper.

The polymer composition based on ethylene that can be used for embodiments of the present invention is characterised by CDC Be 75 to 220.The application includes and discloses all single value and the subinterval of 75 to 220；Example As, the CDC of polymer composition based on ethylene can from 75,95,115,135,155,175, Or the upper limit of the lower limit to 80,100,120,140,160,180 or 220 of 195.Such as, based on The comonomer distribution constant of the polymer composition of ethylene can be 75 to 200 or 100 to 180, Or 110 to 160 or 120 to 155.

The further feature of the polymer composition based on ethylene that can be used for embodiment of the present invention exists It is that 30 to 100 vinyls each million are present in polymerization based on ethylene in vinyl degree of unsaturation Carbon atom (vinyl/1,000,000C) in the main chain of compositions.The application includes and discloses 30 All single value and subinterval to 100 vinyl/1,000,000C；Such as, vinyl insatiable hunger Can be from 30 vinyl/1,000,000C, 40 vinyl/1,000,000C, 50 ethylene with degree Base/1,000,000C, 60 vinyl/1,000,000C, 70 vinyl/1,000,000C, 80 The lower limit of vinyl/1,000,000C or 90 vinyl/1,000,000C is to 35 vinyls / 1,000,000C, 45 vinyl/1,000,000C, 55 vinyl/1,000,000C, 65 second Thiazolinyl/1,000,000C, 75 vinyl/1,000,000C, 85 vinyl/1,000,000C, 95 Individual vinyl/1,000,000C or the upper limit of 100 vinyl/1,000,000C.Such as, vinyl Degree of unsaturation can be 30 vinyl/1,000,000C to 100 vinyl/1,000,000C or 40 vinyl/1,000,000C to 90 vinyl/1,000,000C or 50 vinyls / 1,000,000C to 70 vinyl/1,000,000C or 40 vinyl/1,000,000C to 70 Individual vinyl/1,000,000C.

The further feature of the polymer composition based on ethylene that can be used for embodiment of the present invention exists It is at least 2.5 to 15 in ZSVR.The application includes and discloses all single value of 2.5 to 15 And subinterval；Such as, the ZSVR of polymer composition based on ethylene can from 2.5,3.5,4.5, 5.5, the lower limit of 6.5,7.5,8.5,9.5,10.5,11.5,12.5,13.5 or 14.5 to 3,4,5, 6, the upper limit of 7,8,9,10,11,12,13,14 or 15.Such as, polymer based on ethylene The ZSVR of compositions can be 2.5 to 15 or 4 to 12 or 3.5 to 13.5 or 5 to 11.

The further feature of the polymer composition based on ethylene that can be used for embodiment of the present invention exists It is 0.924g/cm in density³To 0.940g/cm³.The application includes and discloses 0.924g/cm³Extremely 0.940g/cm³All single value and subinterval；Such as, polymer composition based on ethylene is close Degree can be from 0.924g/cm³、0.925g/cm³、0.930g/cm³Or 0.935g/cm³Lower limit to 0.925 g/cm³、0.930g/cm³、0.935g/cm³, or 0.940g/cm³The upper limit.Such as, based on ethylene The density of polymer composition can be 0.924g/cm³To 0.940g/cm³, or 0.925g/cm³Extremely 0.936g/cm³, or 0.924g/cm³To 0.928g/cm³, or 0.932g/cm³To 0.936g/cm³。

The further feature of the polymer composition based on ethylene that can be used for embodiment of the present invention exists In melt index (MI) (I₂) be 0.1g/10min to 1g/10min.The application includes and discloses 0.1g/10 The all single value of min to 1g/10min and subinterval；Such as, combination of polymers based on ethylene The I of thing₂Can be from 0.1g/10min, 0.2g/10min, 0.3g/10min, 0.4g/10min, 0.5g/10 The lower limit of min, 0.6g/10min, 0.7g/10min, 0.8g/10min or 0.9g/10min is to 0.15 g/10min、0.25g/10min、0.35g/10min、0.45g/10min、0.55g/10min、0.65g/10 The upper limit of min, 0.75g/10min, 0.85g/10min, 0.95g/10min or 1g/10min.Example As, the I of polymer composition based on ethylene₂Can be 0.1g/10min to 1g/10min or 0.2 G/10min to 0.8g/10min or 0.4g/10min to 0.7g/10min or 0.4g/10min is extremely 0.6g/10min。

The further feature of the polymer composition based on ethylene that can be used for embodiment of the present invention exists It is 2.5 to 10 in molecular weight distribution (Mw/Mn).The application includes and discloses all lists of 2.5 to 10 Only value and subinterval；Such as, the Mw/Mn of polymer composition based on ethylene can from 2.5, 3.5, the lower limit of 4.5,5.5,6.5,7.5,8.5 or 9.5 to 3,4,5,6,7,8,9 or The upper limit of 10.Such as, the Mw/Mn of polymer composition based on ethylene can be 2.5 to 10 or 2.5 to 7.5 or 2.75 to 5 or 2.5 to 4.5.

The further feature of the polymer composition based on ethylene that can be used for embodiment of the present invention exists It is 1.5 to 4 in molecular weight distribution (Mz/Mw).The application include and disclose 1.5 to 4 all individually Value and subinterval；Such as, the Mz/Mw of polymer composition based on ethylene can from 1.5,1.75, 2, the lower limit of 2.5,2.75,3 or 3.5 to 1.65,1.85,2,2.55,2.9,3.34,3.79 or The upper limit of 4.Such as, the Mz/Mw of polymer composition based on ethylene can be 1.5 to 4 or 2 To 3 or 2.5 to 3.5 or 2.2 to 2.4.

The embodiment of the multilayered shrink films of the present invention demonstrates that one or more are selected from the property of following character Matter: 45 degree of glossiness of at least 50%, total mist degree of 15% or less, the internal haze of 8% or less, The 1%CD secant modulus of 43,000psi or bigger, the 1%MD secant modulus of 38,000psi or bigger, The CD shrink tension of at least 0.7psi and the MD shrink tension of at least 10psi.Multilayered shrink films is permissible Demonstrate in these character any one, the combination in any of these character, or alternatively, demonstrate All these character.Such as, in one embodiment, multilayer film can demonstrate at least 50% 45 degree of glossiness, the internal haze of 8% or less, 1%CD secant moduluss of 43,000psi or bigger. In interchangeable embodiment, multilamellar shrink wrap can demonstrate 38, the 1% of 000psi or bigger The CD shrink tension of MD secant modulus, at least 0.7psi and total mist degree of 15% or less.

The application includes and discloses all single Zhi Hezi district of 45 degree of glossiness of at least 50% Between；Such as, the lower limit of 45 degree of glossiness of multilayered shrink films can be 50%, 55%, 60%, 65%, Or 70%.The application includes and discloses all single Zhi Hezi district of total mist degree of 15% or less Between；Such as, the upper limit of total mist degree of multilayered shrink films can be 10%, 12%, 14% or 15%. The application includes and discloses all single value of internal haze and the subinterval of 8% or less；Such as, The upper limit of the internal haze of multilayered shrink films can be 4%, 5%, 6%, 7% or 8%.The application includes With all single value of 1%CD secant modulus and the subinterval disclosing 43,000psi or bigger；Example As, the lower limit of the 1%CD secant modulus of multilayered shrink films can be 43,000psi or 44,000psi, Or 45,0000psi or 50,000psi or 55,000psi.The application includes and discloses 38,000psi Or all single value of bigger 1%MD secant modulus and subinterval；Such as, multilayered shrink films The lower limit of 1%MD secant modulus can be 38,000psi or 48,000psi or 50,0000psi or 55,000psi.The application includes and discloses all single value of CD shrink tension of at least 0.7psi And subinterval；Such as, the lower limit of the CD shrink tension of multilayered shrink films can be 0.7psi or 0.8psi, Or 0.9psi or 1.0psi.The application includes and discloses the institute of MD shrink tension of at least 10psi There are single value and subinterval；Such as, the lower limit of the MD shrink tension of multilayered shrink films can be 10 Psi or 12psi or 15psi or 18psi.

A kind of embodiment of the multilayered shrink films of the present invention comprises 3 layers altogether, including two top layers and Individual core layer；Wherein said core layer comprises the combination of polymers based on ethylene of 15wt% to 85wt% Thing.The application includes and discloses all single value and the subinterval of 15wt% to 85wt%；Such as, In core layer the amount of polymer composition based on ethylene can from 15wt%, 20wt%, 30wt%, The lower limit of 40wt%, 50wt%, 60wt% or 75wt% to 25wt%, 35wt%, 45wt%, The upper limit of 55wt%, 60wt%, 70wt%, 80wt% or 85wt%.Such as, in core layer The amount of polymer composition based on ethylene can be 15wt% to 85wt% or 20wt% to 65 Wt% or 30wt% to 80wt% or 40wt% to 75wt%.

In a kind of embodiment of the multilayered shrink films of the present invention, each layer also comprises one or more polymerizations Thing, described polymer is selected from polypropylene, polyethylene, ethylene/propene copolymer, ethylene-vinyl acetate (EVA), ethylene/vinyl alcohol copolymer, olefin plastomer and elastomer, the amount of described polymer makes respectively Layer comprises 92.5wt% or more total polymer altogether.The application includes and discloses 92.5wt% extremely The all single value of 100wt% and subinterval；Such as, the total amount of the total polymer of each layer can be from 92.5 The lower limit of wt%, 94.5wt%, 96.5wt%, 98.5wt% or 99.5wt% to 93wt%, 95wt%, The upper limit of 97wt%, 99wt% or 100wt%.Such as, the total amount of the total polymer of each layer can be 92.5wt% to 100wt% or 94wt% to 98wt% or 94wt% to 96wt%.

The replaceable embodiment of multilayered shrink films of the present invention comprises 3 layers altogether, including two top layers and Individual core layer；At least one top layer wherein said comprises the polymerization based on ethylene of 20wt% to 65wt% Compositions.The application includes and discloses all single value and the subinterval of 20wt% to 65wt%； Such as, at least one top layer the amount of polymer composition based on ethylene can from 20wt%, 30 The lower limit of wt%, 40wt%, 50wt% or 60wt% to 25wt%, 35wt%, 45wt%, 55 The upper limit of wt% or 65wt%.Such as, polymer composition based on ethylene at least one top layer Amount can be 20wt% to 65wt% or 25wt% to 55wt% or 35wt% to 55wt%, Or 45wt% to 55wt%.

In specific implementation, the polymer composition based on ethylene in multilayered shrink films Being characterised by that CDC is 120 to 180, vinyl degree of unsaturation is 40 to 60 vinyl/1,000,000 C；ZSVR is 4 to 8；Density is 0.924g/cm³To 0.931g/cm³, melt index (MI) (I₂) it is 0.3 G/10min to 0.6g/10min, molecular weight distribution (Mw/Mn) is 2.0 to 3.3, molecular weight distribution (Mz/Mw) it is 1.5 to 2.5.

In another embodiment, the spy of the polymer composition based on ethylene in multilayered shrink films Levying and be that CDC is more than 90 to 130, vinyl degree of unsaturation is 55 to 70 vinyl/1,000,000 C；ZSVR is 8 to 12；Density is 0.930g/cm³To 0.940g/cm³, melt index (MI) (I₂) it is 0.3 G/10min to 0.6g/10min, molecular weight distribution (Mw/Mn) is 2 to 4, molecular weight distribution (Mz/Mw) Be 1.5 to 3.

In another embodiment, the spy of the polymer composition based on ethylene in multilayered shrink films Levy the carbon atom being in each million main chains being present in polymer composition based on ethylene to contain Total degree of unsaturation (total degree of unsaturation/1,000,000C) less than 120.The application includes and discloses being less than The all single value of 120 and subinterval；Such as, total degree of unsaturation/1, the upper limit of 000,000C can be 90,100,110 or 120.

Polymer composition based on ethylene may reside in the one or more of each layer of multilayered shrink films In.Comprise in the case of more than 3 layers at multilayered shrink films, middle layer is referred to as core layer, will Outermost layer is referred to as top layer, and remainder layer is referred to as subsurface stratum (sub-skin layers).In one embodiment, Polymer composition based on ethylene is present in core layer.In interchangeable embodiment, based on second The polymer composition of alkene is present in one or more top layer.In another embodiment again, based on second The polymer composition of alkene is present in one or more subsurface stratum.In another embodiment again, one Or multiple top layer comprises the polymer composition based on ethylene of 20wt% to 60wt%.In another reality again Execute in mode, one or more subsurface stratums and/or core layer comprise 20wt% to 80wt% based on ethylene Polymer composition.

In some embodiments, the ratio of the thickness on one of top layer of multilayered shrink films and the thickness of core layer Example is 1:20 to 1:2.In specific embodiment, the thickness on one of top layer of multilayered shrink films and core The ratio of the thickness of central layer is 1:10 to 1:3.

The preparation of monolayer shrink films is described in United States Patent (USP) and discloses in 20110003940, draping over one's shoulders this patent Dew content is by with reference to being fully incorporated in the application.

In some embodiments, two top layers of multilayered shrink films comprise linear low density polyethylene (LLDPE) (different from polymer composition based on ethylene), it has 0.912g/cm³To 0.925 g/cm³Density and the I of 0.2g/10min to 2g/10min₂.In one embodiment, multilamellar is received Two top layers of contracting film all comprise LLDPE (different from polymer composition based on ethylene), and it has 0.915g/cm³To 0.922g/cm³Density and the I of 0.5g/10min to 1.5g/10min₂.The application The term " LLDPE (different from polymer composition based on ethylene) " used means gathering containing ethylene Compound, described polymer each of does not demonstrate in following properties: comonomer distribution constant is 75 To 220, vinyl degree of unsaturation is that 30 to 100 vinyls each million are present in based on ethylene Polymer composition main chain in carbon atom；Zero-shear viscosity ratio (ZSVR) is at least 2.5 to 15； Density is 0.924g/cm³To 0.940g/cm³, melt index (MI) (I₂) be 0.1g/10min to 1g/10min, Molecular weight distribution (Mw/Mn) is 2.5 to 10, and molecular weight distribution (Mz/Mw) is 1.5 to 4.

In some embodiments of the present invention, use one or more stabilizers (such as, antioxidant, Such as IRGANOX1010 and IRGAFOS168 (Ciba Specialty Chemicals；Glattbrugg, Switzerland) one or more layers polymer composition of composition shrink film) is processed.Generally, polymer Processed with one or more stabilizers before extrusion or other melting process.At other embodiment Method in, other polymeric additive include but not limited to UV absorbers, antistatic additive, pigment, Dyestuff, nucleator, filler, slip agent, fire retardant, plasticizer, processing aid, lubricant, stable Agent, antismoke agent, viscosity-control additive and antiblocking agent.The polymer composition based on ethylene of the present invention can To comprise one or more the total additives being such as less than 10wt%, based on the present invention based on ethylene Polymer composition and the weight of this additive.

In some embodiments, it is also possible to be compounded into by one or more antioxidants at multilayer film is each Layer one or more in polymer in, subsequently by the polymer prills of this compounding.Such as, based on second The polymer composition of alkene can comprise about one or more phenol antioxidant of 200 parts to about 600 parts Each million parts of polymer based on ethylene.Additionally, polymer composition based on ethylene can comprise about The each million parts of polymerizations based on ethylene of antioxidant based on phosphite ester of 800 parts to about 1200 parts Thing.

Other additive can be joined any one or more of each layer in multilayered shrink films In polymer composition, other additive described includes anti-ignition accelerator (ignition resistant Additives), coloring agent, extender, cross-linking agent, foaming agent and plasticizer.

Any blown film extrusion or co-extrusion method can be used to prepare according to the most discussed herein The multilayered shrink films of embodiment.Blown film extrusion is substantially identical with conventional extrusion molding, until up To die head.Die head in blown film extrusion is typically the vertical cylindrical body with circular open, and it is similar to In pipe die.Diameter can be that several centimeters is to more than 3 meters.By on die head (according to required amount of cooling water, On die head 4 meters to 20 meters or more) a pair nip rolls, upwards melted the moulding of pull-out from die head Material.The speed changing these nip rolls will change the specification (wall thickness) of film.Air ring is placed around die head. When film travels upwardly, air ring cools film.It is air outlet slit at the center of die head, compression can be forced Air enters the center of the round section bar of extrusion from air outlet slit, produces film bubble.This is with certain proportion (mould The several times of head diameter) expand the circular cross section of extrusion.This ratio is referred to as " blow-up ratio " or " BUR ", This ratio can be that only a few percent of green diameter is to exceeding the 200% of green diameter.Nip rolls is by film Bubble flattens into the film of bilayer, and the width (referred to as " flat-folded " (" layflat ")) of described film is equal to the week of 1/2 film bubble Long.(printed on) this film can be wound or imprint subsequently, be cut into definite shape, seal into bag or Other goods.

In some cases, it is possible to use the number of plies that can produce is more than the membrane blowing production line of the required number of plies. It is, for example possible to use the production line of 5 layers prepares the shrink film of 3 layers.In this case, shrink film layer In one or more comprise two or more subgrade (sub-layers), each subgrade has identical composition.

In one embodiment, the invention provides multilayered shrink films according to any aforementioned embodiments, Difference is that each layer also comprises one or more polymer, and described polymer is selected from polypropylene, poly-second Alkene, ethylene/propene copolymer, ethylene-vinyl acetate (EVA), ethylene/vinyl alcohol copolymer, alkene Plastic body and elastomer, the amount of described polymer makes each layer comprise 92.5wt%'s to 100wt% altogether Total polymer.In interchangeable embodiment, the invention provides many according to any aforementioned embodiments Layer shrink film, difference is that this shrink film comprises 3 layers altogether, including two top layers and a core Layer；Wherein core layer comprises the polymer composition based on ethylene of 15wt% to 85wt%.

In interchangeable embodiment, the invention provides multilamellar according to any aforementioned embodiments and shrink Film, difference is that this shrink film comprises 3 layers altogether, including two top layers and a core layer；Its In at least one top layer comprise the polymer composition based on ethylene of 20wt% to 65wt%.Can replace In the embodiment changed, the invention provides multilayered shrink films according to any aforementioned embodiments, difference Place is to use blown film coetrusion to prepare film.In interchangeable embodiment, according to any aforementioned reality The mode of executing the invention provides multilayered shrink films, and difference is polymer composition based on ethylene Being characterised by that comonomer distribution constant is 120 to 180, vinyl degree of unsaturation is 40 to 60 second Thiazolinyl each million is present in the carbon atom in the main chain of polymer composition based on ethylene；ZSVR Being 4 to 8, density is 0.924g/cm³To 0.931g/cm³, melt index (MI) (I₂) be 0.3g/10min extremely 0.6g/10min, molecular weight distribution (Mw/Mn) is 2.0 to 3.3, and molecular weight distribution (Mz/Mw) is 1.5 To 2.5.In interchangeable embodiment, the invention provides multilamellar according to any aforementioned embodiments Shrink film, difference is that polymer composition based on ethylene is characterised by that comonomer distribution is normal Number is 90 to 130, and vinyl degree of unsaturation is that 55 to 70 vinyls each million are present in base Carbon atom in the main chain of the polymer composition of ethylene；Zero-shear viscosity ratio (ZSVR) is 8 to 12； Density is 0.93g/cm³To 0.94g/cm³, melt index (MI) (I₂) be 0.3g/10min to 0.6g/10min, Molecular weight distribution (Mw/Mn) is 2 to 4, and molecular weight distribution (Mz/Mw) is 1.5 to 3.Interchangeable In embodiment, the invention provides multilayered shrink films according to any aforementioned embodiments, difference exists Thickness in one of top layer is 1:20 to 1:2 with the ratio of the thickness of core layer.Interchangeable embodiment party In formula, the invention provides multilayered shrink films according to any aforementioned embodiments, difference is top layer One of the ratio of thickness of thickness and core layer be 1:10 to 1:3.In interchangeable embodiment, The invention provides multilayered shrink films according to any aforementioned embodiments, difference is that two top layers are equal Comprise LLDPE, described LLDPE and there is 0.912g/cm³To 0.925g/cm³Density and 0.2g/10 The I of min to 2g/10min₂.In interchangeable embodiment, according to any aforementioned embodiments originally Invention provides multilayered shrink films, and difference is that two top layers all comprise LLDPE, described LLDPE There is 0.915g/cm³To 0.922g/cm³Density and the I of 0.5g/10min to 1.5g/10min₂。 In interchangeable embodiment, the invention provides multilayered shrink films according to any aforementioned embodiments, Difference is that polymer composition based on ethylene has the I of 0.3g/10min to 0.8g/10min₂ And 0.930g/cm³To 0.940g/cm³Density.

Embodiment

The following example illustrates the present invention, but is not intended to limit the scope of the invention.

The preparation of the polymer composition based on ethylene in the embodiment of the present invention

Embodiment (Inv.Comp.Ex.) 1-3 of the present composition is combination of polymers based on ethylene Thing, it is prepared in double solution polymerization reactor of series connection under conditions of shown in table 1-3.Table 4 Summarize catalyst involved in table 3 and catalytic component.The embodiment 4 of the present composition is base In the polymer composition of ethylene, it enters in double solution polymerization reactor of series connection under conditions of similar Row preparation.

Table 1

Table 2

Table 3

Table 4

The multiple character of embodiment 1-4 of the present composition is shown in table 5-14.

Table 5

Table 6

The embodiment of the present composition	Tm(℃)	Melting heat (J/g)	% crystallizes	Tc(℃)
					1	122.1	165.0	56.5	108.4
2	125.8	179.2	61.4	113.0
					3	124.6	175.9	60.2	112.2
4	124.7	179.3	61.4	112.2

Table 7 (DMS viscosity)

Table 8 (DMS tan δ)

Table 9 (complex modulus and phase angle)

Table 10 (melt strength)

Sample	Melt strength (cN)
		Present composition embodiment 1	5.9
Present composition embodiment 2	5.1
		Present composition embodiment 3	5.6
Present composition embodiment 4	5.5

Table 11 (conventional GPC)

Table 12

Table 13

Table 14

Comparative film embodiment 1 and the preparation of inventive film embodiment 1-8

7 layers of coextrusion membrane blowing production line of the Alpine U.S. are prepared comparative film embodiment 1 and the present invention Film embodiment 1-8.This production line is used barrier screw and 250mm (9.9 inches) coextrusion die by 7 The 50mm30:1 groove feeding extruder composition of head.Die head is processed with following layers distribution: 15/15/13/14/13/15/15, and it is equipped with internal bubble chiller.Each extruder is equipped with Maguire tetra-component blender.Suitable die head bar (die pin) is used to realize 2mm's (78 mil) Die gap.THICKNESS CONTROL is realized, institute by Alpine automatic mode (auto-profile) air ring system State air ring system and employ contactless NDC backscatter thickness measurement system.Use Brampton Engineering64 " dual-stack indexing type winder carrys out rolling film.All seven extruders are provided with Identical extrusion temperature distribution: 4380 °F/district of 3380 °F/district of 2380 °F/district of 170 °F/district of district 5 6450 °F/district of 380 °F/district, the 8450 °F/die head in 7450 °F/district 450 °F.Inventive film embodiment (Inv. Film Ex.) each of which in 1-8 and comparative film embodiment (Comp.Film Ex.) 1 is three layers of shrink film. Table 16 below and table 17 summarize comparative film embodiment 1 and the optical property of inventive film embodiment 1-8 And mechanical performance.Table 20 provides each polymerization in inventive film embodiment and comparative film embodiment The density of compositions (different from the present composition) and I₂。

Table 16

Table 17

Reifenhauser three-layer co-extruded go out to prepare inventive film on membrane blowing production line under the conditions of following real Execute each in example 9-12 and comparative film embodiment 2: die gap=1.8mm；Productivity=140kg/h； And BUR=3.5.The temperature conditions (DEG C) of membrane blowing production line is shown in Table 18.

Table 18

	Extruder A	Extruder B	Extruder C
				Inventive film embodiment 9	232	241	237
Comparative film embodiment 2	232	238	229
				Inventive film embodiment 10	232	234	231
Inventive film embodiment 11	233	234	227
				Inventive film embodiment 12	233	233	225

Table 19 provides the composition information of inventive film embodiment 9-12 and comparative film embodiment 2.

Table 19

Table 20 provides the polymer composition in inventive film embodiment and comparative film embodiment The density of (different from present composition embodiment) and melt index (MI) (I₂)。

Table 20

DOWLEX NG XUS61530.02(“LLDPE-1”)、LDPE132I、DOWLEX2045G LLDPE, ELITE5111G and ELITE5400G are available commercially from The Dow Chemical Company (Midland,MI,USA).Table 21 summarizes inventive film embodiment 9-12 and comparative film embodiment 2 Optical property and mechanical performance.

Table 21

* obtaining according to ASTM D5748 and pierce through data in table 21, difference is to be used Probe diameter be 0.5 inch, rather than 0.75 inch.

Compositions method of testing includes following method: density: measure the sample of density according to ASTM D- 1928 are prepared.Using ASTM D-792, method B was entered in 1 hour that carries out sample compacting Row is measured.Melt index (MI): melt index (MI) or I₂According to ASTM-D1238,190 DEG C/2.16kg of condition Measure, with the grams report of every 10 minutes eluting.I₁₀According to ASTM-D1238, condition 190 DEG C/10kg measures, with the grams report of every 10 minutes eluting.Gel permeation chromatography (GPC): Use high temperature GPC instrument (model PL220, Polymer Laboratories, Inc. are now Agilent) Analyze sample.The GPC test using routine determines that weight average molecular weight (Mw) sum of polymer is divided equally Son is measured (Mn) and determines molecular weight distribution MWD or Mw/Mn.It is also determined that z average molecular weight Mz.Should Method have employed known universal method for correcting based on hydrodynamic volume concept, uses the poly-of narrow ditribution 3 10 μm mixing B posts that styrene (PS) standard specimen works together with the system temperature at 140 DEG C (Polymer Laboratories Inc, now for Agilent) is corrected together.By at 1,2,4-trichloro-benzenes (TCB) it is slowly stirred sample 4 hours in 160 DEG C in, comes 1, with 2mg/mL in 2,4-trichloro-benzenes solvents Concentration prepare polyethylene specimen.Flow velocity is 1.0mL/min, and volume injected is 200 microlitres.Chromatograph is molten Agent and sample preparation solvent contain the Yoshinox BHT (BHT) of 200ppm.Two kinds of solvent source all with Nitrogen bubble.Such as document (T.Williams and I.M.Ward, Polym.Letters, 6,621-624 (1968)) As discussed in, correction factor 0.4316 is used to be converted into poly-by the molecular weight of polystyrene standards Ethylene equivalent molecular weight.Use three grades of multinomials by the polyethylene equivalent molecular weight matching of respective standard specimen For viewed elution volume.Crystallization elution fractionation (CEF) method: use crystallization elution fractionation (CEF) (PolymerChar, in Spain) (B Monrabal etc., Macromol.Symp.257,71-79 (2007)) comonomer distribution analysis is carried out.Will be containing 600ppm antioxidant Yoshinox BHT (BHT) o-dichlorohenzene (ODCB) is used as solvent.Use automatic sampler with 4mg/ml (unless otherwise Illustrate) carry out sample in 160 DEG C and prepare 2 hours under vibration.Volume injected is 300 μ l.CEF's Temperature curve is: with 3 DEG C/min from 110 DEG C to 30 DEG C of crystallizations, 30 DEG C of thermal balances 5 minutes, with 3 DEG C/min is from 30 DEG C to 140 DEG C eluting.Flow velocity during crystallizing is 0.052ml/min.At eluting The flow velocity of period is 0.50ml/min.Data are collected with a data point/second.CEF post is by Dow Chemical Company with the bead (MO-SCI Specialty product) of 125 μm ± 6% and 1/8 inch of stainless steel tube loads.By the requirement of Dow Chemical Company, MO-SCI Specialty carries out pickling to bead.Column volume is 2.06ml.By using NIST standard reference material Material linear polyethylene 1475a (1.0mg/ml) and the eicosane (2mg/ml) mixture in ODCB, come Carry out column temperature correction.By the regulation eluting rate of heat addition so that NIST linear polyethylene 1475a has The peak temperature of 101.0 DEG C and eicosane have the peak temperature of 30.0 DEG C, correct temperature.Use NIST linear polyethylene 1475a (1.0mg/ml) and hexacontane (Fluka, purity, >=97.0%, l mg/ml) Mixture calculate the resolution of CEF post.Achieve hexacontane and the base of NIST polyethylene 1475a Line separates.The area (35.0 DEG C to 67.0 DEG C) of hexacontane and NIST1475a are from 67.0 DEG C to 110.0 DEG C Area ratio be 50:50, the amount < 1.8wt% of the soluble fraction less than 35.0 DEG C.In equation below Defined in the resolution of CEF post:

Its center pillar resolution is 6.0.

Comonomer distribution constant (CDC) method: by the comonomer distribution curve obtained by CEF Calculate comonomer distribution constant (CDC).CDC is defined as comonomer distribution index divided by comonomer The distribution shape factor is multiplied by 100, is shown below:

Comonomer distribution index represent in 35.0 DEG C to 119.0 DEG C co-monomer content at copolymerization list Body burden intermediate value (C_{Intermediate value}) 0.5 times to C_{Intermediate value}1.5 times in the range of the gross weight of polymer chain divide Number.Comonomer distribution form factor is defined as the half-breadth of comonomer distribution curve divided by according to peak value temperature Degree (T_p) the ratio of standard deviation of comonomer distribution curve.

Comonomer distribution constant (CDC) is calculated by the comonomer distribution curve obtained by CEF. CDC is defined as comonomer distribution index and is multiplied by 100 divided by comonomer distribution form factor, such as following formula Shown in:

Wherein comonomer distribution index representative co-monomer content in 35.0 DEG C to 119.0 DEG C is being total to Poly-content of monomer intermediate value (C_{Intermediate value}) 0.5 times to C_{Intermediate value}1.5 times in the range of the gross weight of polymer chain Amount mark, wherein comonomer distribution form factor is defined as the half-breadth of comonomer distribution curve divided by root According to peak temperature (T_p) the ratio of standard deviation of comonomer distribution curve.

According to the following step calculating CDC:

(A) according to following formula by every from 35.0 DEG C to 119.0 DEG C (temperature increment amount is 0.200 DEG C) of CEF Individual temperature (T) obtains weight fraction (w_T(T)):

$\underset{35}{\overset{119.0}{\&Integral;}}{w}_T\left(T\right)\mathrm{dT}=1$

(B) median temperature (T when the accumulating weight mark of 0.500 is calculated according to following formula_{Intermediate value}):

(C) according to following formula, by using co-monomer content calibration trace to calculate at median temperature (T_{Intermediate value}) Time the corresponding intermediate value co-monomer content (C in terms of mole %_{Intermediate value}):

R²=0.997

(D) reference material by using a series of co-monomer content with known quantity builds copolymerization Content of monomer calibration trace, i.e. use CEF with the same experimental conditions specified in CEF experimental section Lower analysis has narrow comonomer distribution and (has unimodal copolymerization list in the CEF of 35.0 DEG C to 119.0 DEG C Body be distributed) and when co-monomer content is 0.0 mole of % to 7.0 mole of % weight average Mw be 35,000 to 11 reference material of 115,000 (being recorded by conventional GPC)；

(E) peak temperature (Tp) and co-monomer content thereof by using each reference material calculate copolymerization Content of monomer corrects；According to following formula by the calculating correction of each reference material:

R²=0.997

Wherein: R²It it is dependent constant；

(F) it is 0.5*C by co-monomer content_{Intermediate value}To 1.5*C_{Intermediate value}Gross weight mark calculate comonomer divide Cloth index, if T_{Intermediate value}Higher than 98.0 DEG C, comonomer distribution index definition is 0.95；

(G) by research 35.0 DEG C to 119.0 DEG C summit each data point (if two peaks are equal, Then select relatively low temperature peaks), cause CEF comonomer distribution curve obtains peak-peak height；Half Width is defined as temperature before at the half of peak-peak height and temperature difference between temperature below, from Study forward temperature before at peak-peak half for 35.0 DEG C, and study backward from 119.0 DEG C Temperature after at big peak value half, in the case of the bimodal distribution that structure is clear and definite, wherein peak temperature Difference equal to or more than 1.1 times of each peak half-breadth summation, then by the polymer group based on ethylene of the present invention The half-breadth of compound is calculated as the arithmetic mean of instantaneous value of each peak half-breadth；

(H) according to the standard deviation (Stdev) of following formula calculating temperature:

$\mathrm{Stdev}=\sqrt{\underset{35.0}{\overset{119.0}{\mathrm{\&Sigma;}}}{(T-T_p)}^2*w_T\left(T\right)}$

Creep zero-shear viscosity measuring method

Zero-shear viscosity obtains through creep test, and this creep is tested at AR-G2 Stress Control flow graph (TA Instruments；New Castle, Del) above use the parallel-plate of 25mm diameter to carry out at 190 DEG C.? Before being made zero by fixing equipment, flow graph baking oven is set in test temperature at least 30 minutes.In test Temperature, is inserted in compression moulded samples disk between two plates so that it is reach balance 5 minutes.Then plate above is made It is reduced to downwards higher than required test gap (1.5mm) 50 μm.Remove any unnecessary material, by upper The plate in face is reduced to required gap.Flow velocity at 5L/min measures under nitrogen purges.Give tacit consent to compacted The change time is set as 2 hours.The constant mild method of 20Pa is applied to all samples steady to guarantee State shear rate as little as be enough to be in newton region.In this study, for sample, gained stable state is cut Cutting speed rate is 10^-3s^-1To 10^-4s^-1.By at log (J (t)), (wherein J (t) is compacted with the graph of a relation of log (t) Becoming compliance, t is creep time) last 10% time window in all data carry out linear regression, come really Determine stable state.If the slope of linear regression is more than 0.97, then it is assumed that reach stable state, then stop creep and survey Examination.Under all situations of this research, the standard that slope meets in 2 hours.By the relation of ε Yu t In last 10% time window of figure, the slope of the linear regression of all data points determines steady state shearing speed, Wherein ε is strain.Zero-shear viscosity is determined by the ratio of the stress applied Yu steady state shearing speed.In order to Determine whether sample degrades in creep test process, to identical sample before and after creep is tested Small amplitude oscillation shearing test is carried out from 0.1rad/s to 100rad/s.The relatively complex viscosity of twice test Value.If the difference at the viscosity number of 0.1rad/s is more than 5%, then it is assumed that sample is in creep test process Degraded, and give up this result.

According to following formula, zero shearing that zero-shear viscosity ratio (ZSVR) is defined as branched polythene material is viscous Degree (ZSV) and the ratio of the ZSV of the linear polyethylene material in equal weight average molecular weight (Mw-gpc):

$\mathrm{ZSVR}=\frac{{\mathrm{\&eta;}}_{0B}}{{\mathrm{\&eta;}}_{0L}}=\frac{{\mathrm{\&eta;}}_{0B}}{2.29\&times;{10}^{-15}{M}_{w-\mathrm{gpc}}^{3.65}}$

ZSV value is obtained at 190 DEG C by creep test by said method.True by conventional GPC method Determine Mw-gpc value.Mutual relation between ZSV and Mw-gpc of linear polyethylene is Linear polyethylene reference material is set up.Description about ZSV-Mw relation can be in ANTEC meeting View finds: Karjala, Teresa P.；Sammler,Robert L.；Mangnus,Marc A.；Hazlitt, Lonnie G.；Johnson,Mark S.；Hagen,Charles M.,Jr.；Huang,Joe W.L.；Reichek, Kenneth N.Detection of low levels of long-chain branching in polyolefins. Annual Technical Conference-Society of Plastics Engineers(2008),66th 887-891。

¹H NMR method: 3.26g material solution is added to the 0.133g in 10mm NMR pipe In polymer sample.Material solution is containing 0.001M Cr³⁺Sym-tetrachloroethane-d₂And perchloro-second (TCE) The mixture (50:50, w:w) of alkene.Solution N in pipe₂Purge 5 minutes, to reduce the content of oxygen. By the sample cell of capping at left at room temperature over night so that polymer samples is swelling.In 110 DEG C vibration under molten Solve sample.Sample does not contains the additive that may affect degree of unsaturation, such as slip agent (such as erucyl amide). 10mm cryoprobe is used to carry out on Bruker AVANCE400MHz spectrometer in 120 DEG C¹H NMR.Carry out twice experiment to obtain degree of unsaturation: control experiment and double presaturation experiment (double pre-saturation experiments).For control experiment, window index function is used to process data, its Middle LB=1Hz, revises baseline to-2ppm from 7ppm.The residue of TCE will be derived from¹The signal of H It is set in 100, by from the integration I of-0.5ppm to 3ppm_AlwaysIt is used as in control experiment, derive from whole gathering The signal of compound.CH in polymer calculated as below₂Group, NCH₂Number: NCH₂=I_Always/2.Right Test in double presaturations, use window index function process data, wherein LB=1Hz, by baseline from 6.6ppm revises to 4.5ppm.The residue of TCE will be derived from¹The signal of H is set in 100, to insatiable hunger Associated quad (I with degree_{1,2-ethenylidene}、I_{Trisubstituted}、I_Vinyl, and I_{Vinylidene base}) based on the region shown in figure below It is integrated:

The number of the unsaturated unit of calculating 1,2-ethenylidene, trisubstituted, vinyl and vinylidene base:

N_{1,2-ethenylidene}=I_{1,2-ethenylidene}/2；N_{Trisubstituted}=I_{Trisubstituted}；N_Vinyl=I_Vinyl/2；N_{Vinylidene base}=I_{Vinylidene base}/2；

Unsaturated unit/1,000,000C:N calculated as below_{1,2-ethenylidene}/ 1,000,000C=(N_{1,2-ethenylidene} /NCH₂)*1,000,000；N_{Trisubstituted}/ 1,000,000C=(N_{Trisubstituted}/NCH₂)*1,000,000；N_Vinyl / 1,000,000C=(N_Vinyl/NCH₂)*1,000,000；N_{Vinylidene base}/ 1,000,000C=(N_{Vinylidene base} /NCH₂)*1,000,000.What degree of unsaturation NMR was analyzed requires to include: for Vd2, quantitative water Putting down is 0.47 ± 0.02/1,000,000 carbon, uses 200 scanning (to obtain less than 1 hour data, bag Include the time running control experiment), use the sample of 3.9wt% (about Vd2 structure, to see Macromolecules, vol.38,6988,2005), 10mm high temperature cryoprobe.Quantitative level is fixed Justice is 10 for signal to noise ratio.Proton is remained for deriving from TCT-d2¹H signal, chemical shift reference It is set in 6.0ppm.Use ZG pulse TD32768, NS4, DS12, SWH10,000Hz, AQ1.64s, D114s carry out control experiment.Use the pulse sequence O1P1.354ppm, O2P revised 0.960ppm, PL957db, PL2170db, TD32768, NS200, DS4, SWH10,000 Hz, AQ1.64s, D11s, D1313s carry out double presaturation experiment.Use Bruker AVANCE The corrected impulse order about degree of unsaturation of 400MHz spectrometer is as follows:

DSC degree of crystallinity: differential scanning calorimetry (DSC) may be used for the temperature survey polymerization in wide scope Melted and the crystallographic property of thing.Such as, will be equipped with RCS (refrigerating/cooling system) and automatic sampler TA Instruments Q1000DSC is used for carrying out this analysis.In test process, use 50L/min Nitrogen purging air-flow.Each sample is melted at about 175 DEG C and is pressed into thin film；Then melted sample is empty

Air cooling is to room temperature (～25 DEG C).The sample of 3-10mg, 6mm diameter is extracted from the polymer of cooling, Weighing, be placed in light aluminum pot (about 50mg), crimping is closed.It is analyzed subsequently, to determine it Thermal property.Produce the curve of heat flow and temperature by making sample temperature raising and lowering, determine The thermal behavior of sample.First, sample is quickly heated up to 180 DEG C, keep constant temperature 3 minutes, to eliminate Its thermal history.Then, with the cooldown rate of 10 DEG C/min, sample is cooled to-40 DEG C ,-40 DEG C of guarantors Hold constant temperature 3 minutes.(this is " to heat the sample to 150 DEG C with the rate of heat addition of 10 DEG C/min subsequently Two heating " heat up).Record cooling and the second heating curves.By initial to-20 DEG C of setting bases from crystallization Line endpoints analyzes cooling curve.By analyzing heating from-20 DEG C to melted end setup baseline end points Curve.The value determined is peak melt temperature (T_m), peak crystallization temperature (T_c), melting heat (H_f) (with Jiao Every gram of ear is counted) and the % degree of crystallinity of the use calculated polyethylene specimen of following formula: % degree of crystallinity= ((Hf)/(292J/g))x100.According to the second heating curves record melting heat (H_f) and peak melt temperature. Peak crystallization temperature is determined by cooling curve.

Dynamic mechanical spectroscopy (DMS) frequency scan: 350 °F in 1500psi pressure by resin at air In be compression molded into the circular print of 3mm thickness x1 inch, last 5 minutes.Subsequently by sample from press Take out, be placed on enumerator cooling.Use " the height of the TA Instruments being equipped with 25mm parallel-plate Level rheological characteristic amplification system (Advanced Rheometric Expansion System) (ARES) " at nitrogen Constant temperature frequency scanning is carried out under purging.Sample is placed on plate so that it is melt 5 minutes at 190 DEG C.With After make each plate close to 2mm, repair sample, then begin to test.The method has other 5 minutes Built-in delay so that hygral equilibrium.In 190 DEG C in the frequency range of 0.1rad/s to 100rad/s Test.Strain amplitude is constant 10%.According to amplitude with analyze stress response mutually, stress ring Storage modulus (G '), loss modulus (G "), complex modulus (G*), dynamic viscosity η * and tan (δ) should be calculated Or tan δ.

Melt strength: 190 DEG C of uses71.97(Inc.；Rock Hill, SC) measure melt strength, use the plane entering angle (flat being furnished with length 30mm, diameter 2mm Entrance angle) (180 degree)2000 capillary rheometer feeding melts.Will Pellet is fed in machine barrel (L=300mm, diameter=12mm), is compressed so that it is melted 10 minutes, Being extruded with the constant piston speed of 0.265mm/s afterwards, described constant piston speed is equal to given The 38.2s of die head size^-1Wall shear rate.Extruded stock is placed through 100mm under die head exit The Rheotens wheel at place, is taken turns by this with 2.4mm/s²Acceleration it is pulled out downwards.To be applied to Power (in terms of cN) on wheel is reported as the function of wheel speed (in terms of mm/s).Melt strength is reported as Stability force (cN) before strands fracture.

Film method of testing includes following method: total (all) mist degrees and internal haze: according to ASTM D 1003-07 measures internal haze and total mist degree.Mineral oil (1-2 teaspoon) is used to obtain by refractive index match Obtain internal haze, wherein mineral oil is applied on each surface of film as coating.By Hazegard Plus (BYK-Gardner USA；Columbia, MD) it is used for testing.For each test, check five samples, Report meansigma methods.Sample size is " 6in x6in ".45 ° of glossiness: ASTM D2457-08 (five The meansigma methods of membrane sample；Each sample is " 10in x10in ").Transparency: ASTM D1746-09 (five The meansigma methods of individual membrane sample；Each sample is " 10in x10in ").1% and 2% secant modulus-MD (adds Work direction) and CD (laterally): ASTM D882-10 (five membrane samples are in the meansigma methods of all directions；Various kinds Product are " 1in x6in ").CD and MD ultimate elongation, CD and MD stretch peak load, CD With MD ultimate elongation, CD and MD stretching yield strain, CD and MD tensile yield strength: (five membrane samples are in the meansigma methods of all directions；Each sample is " 1in x6in ").CD and MD stretches Thickness: ASTM D882-10.MD and CD Elmendorf tearing strength: ASTM D1922-09 (15 Individual membrane sample is in the meansigma methods of all directions；Each sample is the semilune of " 3in x2.5in ").Dart impact Intensity: (minimum 20 boomerangs reach 50% and rupture ASTM D1709-09；Usually 10 " 10in x36in " Bar).Pierce through intensity: at the INSTRON using SINTECH TESTWORKS software version 3.10 Measure in model 4201 and pierce through (in addition to the data in table 21).Specimen size is " 6in x6in ", Carry out four times to measure, averagely pierce through value to determine.Film is regulated 40 hours, at ASTM after film preparation Regulation at least 24 hours in the laboratory (23 DEG C and 50% relative humidity) controlled.By " 100lb " pressure measurement The circular sample seat of element and 4 inch diameters is used together.Piercing through probe is that " maximum traveling is a length of 7.5 inches " " 1/2 inch diameter " stainless steel ball (2.5 " bar on) of polishing.There is no gauge length (gauge Length), probe is as close possible to sample, but does not contact sample (by rising probe until it contacts sample Set probe).Then probe it is gradually lowered, until it does not contact sample.Subsequently, crosshead is set It is set to 0.In view of maximum travel distance, this distance would be about 0.10 inch.Crosshead speed is 10 English Very little/minute.Thickness is measured in the middle of sample.Use the thickness of film, crosshead advance distance and Peak load is determined by software and pierces through.After the test of each sample, use " KIM-WIPE " Cleaning pierces through probe.Shrink tension: according at Y.Jin, T.Hermel-Davidock, T.Karjala, M. Demirors, J.Wang, E.Leyva, and D.Allen, " Shrink Force Measurement of Low Shrink Force Films ", SPE ANTEC Proceedings, p.1264 the method described in (2008) is come Measure shrink tension.By there is film fixing the RSA-III dynamic mechanical analyzer (TA of equipment Instruments；New Castle, DE) on the variations in temperature that carries out measure the contraction of membrane sample and open Power.For test, on machine direction (MD) or horizontal (CD), from membrane sample, cross cutting obtains " 12.7 Mm width " and the film sample of " 63.5mm length ".Indicated by Mitutoyo Absolute digimatic Film thickness measured by device (model C 112CEXB).The wide-measuring range of this indicator is 12.7mm, and Resolution is 0.001mm.By the meansigma methods of three thickness measures of various location on each film sample And the width of sample is for calculating the cross-sectional area (A) of film, wherein by " the A=width X thickness of film sample Degree " test for shrink film.The standard film deriving from TA Instruments is stretched fixing equipment be used for surveying Amount.Before being made zero in gap and axial force, the baking oven of RSA-III is made to balance at least 30 points at 25 DEG C Clock.Primary clearance is set as 20mm.Then film sample is connected to fixing equipment above and following On fixing both equipment.Generally, the measurement of MD only needs the film of a layer.Due in the cd direction Shrink tension the lowest, so by the membrane stack of two-layer or four layers together to improve in measure every time Signal to noise ratio.In this case, film thickness is the summation of whole layer.In our current research, in the MD direction Use monolayer, use two layers in the cd direction.After film reaches the initial temperature of 25 DEG C, slightly Micro-fixing equipment being manually raised and lowered above, to obtain the axial force of-1.0g.This is for guaranteeing The beginning of test will not occur distortion or the excessive tensile of film.Then test is started.At whole test process Period keeps constant fixing equipment gap.Alternating temperature starts with the speed of 90 DEG C/min, from 25 DEG C to 80 DEG C, then with the speed of 20 DEG C/min from 80 DEG C to 160 DEG C.The change phase of 80 DEG C to 160 DEG C Between, when film shrinks, by being recorded as the function of temperature by the contractility of force sensor measuring, for entering One step analysis.By the difference between " peak force " and " baseline value before contractility peak value starts " It is considered the contractility (F) of film.The shrink tension of film is the ratio of contractility (F) and the cross-sectional area (A) of film. Free shrink: by the 4x4 of sample " sample is placed in film holder, soaked temperature required subsequently In hot oil bath 30 seconds.The oil used is Dow Corning210H.After the 30 seconds, removal mould Holder/sample so that it is cooling, at machine direction and laterally measures sample on the two subsequently.Then by The initial length Lo of sample and the survey of new length Lf measured after above method processes in hot oil bath Amount result calculates % shrinkage factor.% shrinkage factor=[(Lf-Lo)/Lo] * 100.

Unless otherwise specified, from the hint of context or this area convention, the most all of number and Percent is based on weight.By the application of all references, disclosure, patent, method of testing and other file (including priority document) by with reference to being fully incorporated the application, the degree being incorporated to make the disclosure with Disclosed compositions is consistent with method, and meets this all permissions being incorporated to of permission.

On the premise of without departing from the essence of the present invention and inner characteristic, available embodied in other this Bright, accordingly, as instruction the scope of the present invention, should be with reference to appended claim, rather than preceding description.

Claims (9)

1. multilayered shrink films, it comprises:

Three layers, including two top layers and a core layer；

One of them top layer comprise 10wt% to 100wt% to derive from one or more based on ethylene poly- The unit of polymer composition, described polymer composition based on ethylene be characterised by CDC be 90 to 130, vinyl degree of unsaturation is 46 to 62 vinyl/1,000,000C；ZSVR is at least 6.03 To 8.70；Density is 0.928g/cm³To 0.936g/cm³, melt index (MI) I₂For 0.3g/10min to 0.6 G/10min, molecular weight distribution mw/mn is 2 to 4, and molecular weight distribution Mz/Mw is 1.5 to 3；

Other in which top layer comprise 50wt% to 65wt% to derive from one or more based on ethylene poly- The unit of polymer composition, described polymer composition based on ethylene be characterised by CDC be 90 to 130, vinyl degree of unsaturation is 46 to 62 vinyl/1,000,000C；ZSVR is at least 6.03 To 8.70；Density is 0.928g/cm³To 0.936g/cm³, melt index (MI) I₂For 0.3g/10min to 0.6 G/10min, molecular weight distribution mw/mn is 2 to 4, and molecular weight distribution Mz/Mw is 1.5 to 3；

Wherein multilayer film demonstrates: 45 degree of glossiness of at least 50%, total mist degree of 15% or less, The internal haze of 8% or less, the 1%CD secant modulus of 43,000psi or bigger, 38,000psi or Bigger 1%MD secant modulus, the CD shrink tension of at least 0.7psi and at least 10psi's MD shrink tension.

2. the multilayered shrink films of claim 1, the most each layer also comprises one or more polymer, institute State polymer selected from polypropylene, polyethylene, ethylene/propene copolymer, ethylene-vinyl acetate (EVA), Ethylene/vinyl alcohol copolymer, olefin plastomer and elastomer, the amount of described polymer makes each layer comprise The total polymer of 92.5wt% to 100wt% altogether.

3. the multilayered shrink films of claim 1, wherein said core layer comprises 30wt%'s to 60wt% Polymer composition based on ethylene, described polymer composition based on ethylene is characterised by CDC Being 90 to 130, vinyl degree of unsaturation is 46 to 62 vinyl/1,000,000C；ZSVR be to Few 6.03 to 8.70；Density is 0.928g/cm³To 0.936g/cm³, melt index (MI) I₂For 0.3g/10min To 0.6g/10min, molecular weight distribution mw/mn is 2 to 4, and molecular weight distribution Mz/Mw is 1.5 To 3.

4. the multilayered shrink films of claim 3, wherein said core layer comprise 40wt% described based on The polymer composition of ethylene and the polyethylene of 60wt%, described polyethylene has 0.918g/cm³Extremely 0.960g/cm³Density and the I of 0.2 to 2₂。

The multilayered shrink films of any one of the most aforementioned claim, wherein uses coextrusion method to prepare institute State film.

6. the multilayered shrink films of any one of claim 1-4, wherein said polymer based on ethylene Compositions is characterised by that molecular weight distribution mw/mn is 2.0 to 3.3, and molecular weight distribution Mz/Mw is 1.5 to 2.5.

7. the multilayered shrink films of any one of claim 1-4, the thickness on one of wherein said top layer with The ratio of the thickness of described core layer is 1:10 to 1:3.

8. the multilayered shrink films of any one of claim 1-4, two of which top layer all comprises and is different from The LLDPE, described LLDPE of described polymer composition based on ethylene have 0.912g/cm³Extremely 0.925g/cm³Density and the I of 0.2g/10min to 2g/10min₂。

9. the multilayered shrink films of any one of claim 1-4, two of which top layer all comprises and is different from The LLDPE, described LLDPE of described polymer composition based on ethylene have 0.915g/cm³Extremely 0.922g/cm³Density and the I of 0.5g/10min to 1.5g/10min₂。