• 专利附录
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    • 专利摘要:
    The present invention is used as an outer packaging of a cigarette pack or tobacco carton comprising a polypropylene containing core layer comprising at least 70% by weight of a uniaxial heat shrinkable biaxially oriented multilayer film and at least one polyolefin containing shell layer adjacent to the core layer. The present invention relates to a uniaxial heat shrinkable biaxially oriented multilayer film, which is prepared by biaxially orientating the coextrusion and then stretching the coextrusion 10 to 40% in the longitudinal direction. The core layer contains isotactic polypropylene and modifiers that reduce the crystallinity of the polypropylene containing core. Such modifiers may be selected from the group consisting of atactic polypropylene, syndiotactic polypropylene, ethylene-propylene copolymers, propylene-butene-1 copolymers, ethylene-propylene-butene-1 terpolymers and straight chain low density polyethylenes. . The outer layer is selected from the group consisting of polypropylene, ethylene-propylene copolymers, polyethylene and ethylene-propylene-butene-1 terpolymers, which contain silicone oils.
    公开号:KR20010013586A
    申请号:KR19997011593
    申请日:1998-05-21
    公开日:2001-02-26
    发明作者:번즈도날드존；라이스트만데이비드오거스트；라이스배리캐머런
    申请人:데니스 피. 산티니；모빌 오일 코포레이션；
    IPC主号:
    专利说明:

    Method for use as a uniaxial shrinkable biaxially oriented polypropylene film and cigarette pack packaging material
    As disclosed in US Pat. No. 4,194,039, polyolefins can be used to make shrink films for packaging materials. Other suitable synthetic resins include various ionomers, polyvinyl chlorides, polyesters, polystyrenes and polyvinylidene chlorides.
    A unique feature of the shrink film is its ability to create shrinkage tension in the film even if it does or does not shrink upon exposure to some heat. This property is activated by the baler as the packaged product passes through the hot air or hot water shrinkage tunnel. Shrinkage in the film results in aesthetically pleasing transparency that can be deformed to conform to the product's contours while providing the general functionality needed for packaging materials such as component loss, loss or protection from damage due to handling and transportation. Or opaque packaging. Examples of items typically packaged in polyolefin shrink films include toys, play equipment, athletic articles, stationery, greeting cards, hardware and household products, office supplies, office equipment, foodstuffs, gramophone recorders, and industrial parts.
    The production of shrink films includes extrusion lines with "racking" capability, irradiation units in the case of crosslinking, tenter frames, mechanical centerfolders and slitters. It requires a relatively sophisticated device. "Racking" or "tenter framing" corresponds to a conventional orientation process that draws a film in the transverse or transverse and longitudinal or machine directions. Films are generally heated to a range of orientation temperatures that vary with different polymers, but this temperature range is typically above room temperature and below the melting point of the polymer. After stretching of the film, the film is rapidly cooled to cool the film molecules in the oriented state in order to quench. Upon heating, the oriented stress relaxes and the film begins to return to its original non-oriented dimensions.
    Particular applications such as labeling, cabaling or packaging of materials such as boxes, plates, containers, bottles, tubes, cylindrical materials (eg pipes) and rods can be coated with heat shrinkable films in particular. However, in certain circumstances it may be necessary to contract along a single axis without substantial contraction in the transverse direction. For example, if the film shrinks in the longitudinal direction in the process of labeling a bottle by shrinking a tube of heat shrinkable material, the label may be placed at a position higher than the desired position upon shrinkage, rather than at the desired position. . Moreover, such label surface printing and other conversion processes require thermal stability in substantially one direction to meet machinability requirements. The uniaxial shrinkable material can be used in the manufacture of a container in which a uniaxial shrinkable film which shrinks a package is tightly packed by lap heating welding.
    To obtain a uniaxial shrinkable material, uniaxially oriented materials, ie materials oriented in only one direction, can be used. However, uniaxially oriented films may lack the necessary strength and toughness needed for use in such applications. Since biaxially oriented films exhibit desirable strength and tear resistance in both directions of orientation, it is desirable to obtain a biaxially oriented, substantially uniaxial heat shrinkable film that is stable in the transverse direction.
    References disclosed in more detail for heat shrinkable films include US Pat. No. 4,194,039, as well as US Pat. No. 3,808,304; 4,188,350; 4,377,616; 4,377,616; No. 4,390,385; 4,448,792, 4,582,752 and 4,963,418.
    U.S. Pat.No. 5,292,561 (corresponding to EPA 0498249) discloses a unidirectional shrinkage (more than 10% longitudinal shrinkage at 100 ° C. and 2) under conditions including the mechanical longitudinal / transverse draw ratio of longitudinal reorientation of 1.01 to 7.5. A method for producing polyolefin shrink films with high transverse shrinkage of less than% is disclosed. The bottom layer of the film contains a propylene polymer and optionally hydrogenated hydrocarbon resin.
    EPA 0204843 discloses a low temperature shrinkable film comprising a straight chain low density polyethylene resin having a film shrinkage property of at least 30% in the longitudinal direction and at most 5% in the transverse direction at 90 ° C., which has a draw-out ratio in the longitudinal direction. A high (3-5) film is taken out and manufactured.
    EPA 0321964 extrudes shrink films from one or more C 3 -C 6 alphaolefins and straight chain low density copolymers of ethylene to provide materials having a longitudinal shrinkage of at least 30% and a transverse shrinkage of at least 10% at 135 ° C. A method is disclosed.
    EPA 0477742 discloses transparent polypropylene shrink films having a longitudinal shrinkage of at least 10% and a transverse shrinkage of less than 2% at 100 ° C. The polypropylene comprises up to 15%, preferably 2 to 6% of n-heptane soluble components.
    EPA 0299750 discloses uniaxial or biaxially stretched films having a heat shrinkage of at least 20% in one of the longitudinal and transverse directions and a heat shrinkage of at least 60% in the other. The film mainly comprises straight chain polyethylene and optionally branched low density polyethylene.
    EPA 0595270 discloses a heat weldable laminate having a high unidirectional shrinkability made from a combination of polypropylene and copolymers of propylene with small amounts of ethylene or alphaolefins or biaxially oriented polymer films such as biaxially oriented polypropylene. have. Uniaxial shrinkage is obtained by balancing longitudinal reorientation process variables such as temperature, draw rate, linear velocity and oriented polymer film properties. Thermal weldability is imparted by the presence of a thermal welding layer.
    U.S. Patent Nos. 4,058,645, 4,604,324, 4,764,425, and 4,911,976 disclose films suitable for high speed packaging processes such as high speed tobacco pack packing machines and tobacco carton packing machines. Nevertheless, despite the development of film packaging techniques as exemplified by the aforementioned patent documents, these films have one or more disadvantages. For example, when several films are used in a high speed tobacco package packaging machine, these films tend to stick to each other and wrinkles, especially at the site where thermal welding occurs.
    It is a first object of the invention to provide a uniaxial heat shrinkable biaxially oriented multilayer film comprising a silicone oil containing skin layer and a polypropylene core for use as outer packaging of a cigarette pack or carton.
    The present invention relates to a uniaxial heat shrinkable biaxially oriented multilayer film comprising a polypropylene containing core layer and at least one polyolefin containing envelope layer located adjacent to the core layer, wherein the core layer reduces the degree of crystallinity of the polypropylene containing core layer. And isotactic polypropylene, and the outer layer contains silicone oil.
    The present invention relates to the field of polymer films, and more particularly to uniaxial heat shrinkable and biaxially oriented polypropylene films.
    1 illustrates an apparatus for measuring the adhesion of a cigarette pack wrapper.
    core
    The composition of the polypropylene-containing core layer in the multilayer film of the present invention is low enough to permit secondary orientation of the film without breaking the film after biaxial orientation and provides sufficient operability to exhibit crystallinity which imparts uniaxial shrinkage to the film. You must do it. The core layer material may be a single atactic single polypropylene homopolymer material having a specific melting point and measured, for example, by DSC (differential scanning calorimetry) at a heating rate of 2 ° C. per minute. Alternatively, the core layer material may include polypropylene and modifiers that are highly isotactic, and the modifiers are more likely to crystallize than isotactic polypropylene due to high chain defects or low isotacticity (whether or not blended). Polyolefin materials having little or other tacticity, such as atactic or syndiotactic polypropylene. A suitable DSC melting point for the core layer, with or without blending, may be less than 160 ° C, such as less than 150 ° C, even less than 140 ° C.
    Modifiers suitable for use in the present invention include polyolefins in addition to isotactic polypropylene. Modifiers include atactic polypropylene, syndiotactic polypropylene, ethylene-propylene copolymers, propylene-butene-1 copolymers, ethylene-propylene-butene-1 terpolymers, polybutene-1 and straight chain low density polyethylene You can choose from the configured groups.
    Several methods have been found that can provide a polypropylene core having the desired crystallinity after primary orientation. The desired degree of crystallinity can avoid tearing biaxially oriented films at greater than 30% or greater than 35%, such as up to 40% or even up to 45% of elongation during the secondary orientation process. Isotactic polypropylene, ie, polypropylene with less than 5% atactic, ie less than 3% atactic, may be mixed with a modifier, such as atactic polypropylene, to provide a suitable core layer. Atactic content can be measured by the insolubility of the polymer when boiling n-hexane, and chain defects or atactic differences are observed through NMR testing.
    In a first aspect of the invention, modifiers, such as atactic polypropylene, have an overall atacticity of greater than 2%, preferably greater than 4%, greater than 5% or greater than 6%, such as 6-15%. It is added to the core in an amount sufficient to provide the core layer. For this purpose, the atacticity of atactic polypropylene is at least 10%, preferably at least 15%, such as 15-20% or 15-25%. Atactic polypropylene is used alone as a core, or in such a way that the resulting mixture comprises 10 to 99% by weight atactic polypropylene, such as 10 to 30% by weight, preferably 15 to 20% by weight atactic polypropylene. Can be added to isotactic polypropylene. Particular preference is given to a combination of 15% by weight atactic polypropylene (15% atacticity) and 85% by weight isotactic polypropylene (4-5% atacticity).
    Atactic polypropylenes suitable for use in the present invention contain 15% of atactic polypropylene, which can be added to the isotactic polypropylene to provide a core mixture that increases the total core atacticity by 2.25% by weight. Have a tea city
    Commercial isotactic propylenes suitable for use in the present invention include Fina 3371, available from the Department of Chemistry of Pina Oil & Chemical Company, Dallas, Texas. Commercially available atactic polypropylenes include L1300 from Novolen of BASF Corporation in Farnoffy, NJ.
    In a second aspect of the present invention, the invention provides 2-15% by weight of polybutene-1, preferably using a core layer comprising the aforementioned polypropylene, preferably isotactic polypropylene, mixed with a polybutene-1 modifier. Preferably, a core layer containing 5 to 10% by weight of polybutene-1 is provided. Suitable polypropylene / polybutene-1 homogeneous blends are disclosed in US Pat. No. 3,808,304. This disclosure teaches blends containing 30 to 90 parts by weight of polypropylene and 70 to 10 parts by weight of corresponding polybutene-1. Examples of suitable polybutene-1 include PB 8430 available from Shell Chemical Company, Houston, Texas.
    In a third aspect of the invention, the core layer is the aforementioned polypropylene, preferably mixed with an ethylene-propylene copolymer modifier, such as from 2 to 10% by weight ethylene-propylene copolymer, preferably from 3 to 10% by weight EP copolymer. Preferably isotactic polypropylene. Suitable EP copolymers may contain 2 to 7% by weight ethylene, the remainder being propylene. The melt index of the copolymer at 230 ° C. is generally 2 to 15, preferably 3 to 8. Melting | fusing point of a crystal is generally 125-150 degreeC, and a number average molecular weight is 25,000-100,000. The density is preferably 0.89 to 0.92 g / cm 3 . Suitable EP copolymers include EP8573, available from the Department of Chemistry of Pina Oil & Chemical Company, Dallas, Texas.
    In a fourth aspect of the invention, the core layer is a blend of the aforementioned polypropylene, preferably isotactic polypropylene, mixed with 0-10% by weight ethylene-propylene copolymer, the copolymer being 0.5-1% by weight ethylene And the remainder is preferably 50 to 100% by weight EP copolymer containing propylene. Some of these copolymers are commercially available as preformed resins containing 0.6 wt% ethylene (4173 available from Pina).
    In a fifth aspect of the invention, the core layer is a blend of the aforementioned polypropylene, preferably isotactic polypropylene, mixed with the propylene-butene-1 copolymer. The core layer may comprise 5-20% by weight, preferably 10-20% by weight of propylene-butene-1 copolymer. Suitable propylene-butene-1 copolymers include Cefor SRD4-105 and Cefor SRD-104, such as those sold by Shell Chemical Company. The core layer may comprise 5-20% by weight of propylene-butene-1 copolymer as modifier.
    In a sixth aspect of the invention, the core layer is a blend of the aforementioned polypropylene, preferably isotactic polypropylene, mixed with straight chain low density polyethylene (LLDPE). Typically the melt index of these polymers is from 1 to 10. The density of the straight chain low density polyethylene should be 0.88 to 0.94 g / cc, preferably 0.89 to 0.92 g / cc. Straight chain low density polyethylene can be derived from ethylene with other higher comonomers such as butene-1, hexene-1 or octene-1. The core layer may comprise 2-15 wt% LLDPE, preferably 5-10 wt% LLDPE. Examples of commercially available LLDPE include Exact 2009, Exact 2010, and Exact 3016, which are commercially available from Exxon Chemical Company.
    In a particularly preferred embodiment, the core layer is a combination of the above-mentioned polypropylene, preferably isotactic polypropylene, mixed with syndiotactic polypropylene and optionally ethylene-propylene copolymer. Syndiotactic polypropylene is 2 to 10% by weight, ie 4 to 8% by weight, preferably 4 to 6% by weight, with 0 to 40% by weight ethylene-propylene copolymer, preferably 0 to 20% by weight EP copolymer. May be present in the core layer in an amount of%. Suitable E-P copolymers are as described above. The presence of the E-P copolymer results in improved longitudinal tensile strength in the secondary orientation step. However, the EP copolymer content may cause undesired film stretching even at low temperatures such as 60 ° C. (140 ° F.) drying temperatures and because such stretching may cause print registration problems in processing processes such as printing. You have to measure carefully.
    Syndiotactic polypropylenes used as modifiers in the present invention may have an average length of sequences of less than 15%, in particular less than 6%. The average length of the sequence ˜n r of the syndiotactic sequence is preferably greater than 20, more preferably greater than 25. The molar mass distribution follows the relationship of Equation 1 below.
    M w = k × M n
    Where
    M w represents the weight average of the molar mass distribution,
    M n represents the number average of the molar mass distribution,
    k is a factor of 1 to 5, preferably 2 to 3.
    The weight average is preferably 60,000 to 250,000, in particular 90,000 to 160,000. Average molar mass can be measured by a conventional method, and gel permeation chromatography method was found to be especially suitable among these.
    Commercial syndiotactic polypropylene resins suitable for use in the present invention include EOD 9306 and EOD 9502 available from Pina.
    In a seventh aspect of the invention, the core layer is a blend of the aforementioned polypropylene, preferably isotactic polypropylene, mixed with ethylene-propylene-butene-1 terpolymer as a modifier. The core layer may comprise 5-20% by weight of terpolymer. Suitable terpolymers are those containing 3-5 wt% ethylene and 3-6 wt% butene-1. Such terpolymers are commercially available from Chisso under the trade name Chisso 7700 series. Other suitable ethylene-propylene-butene-1 terpolymers include those containing 0.5 to 3 weight percent ethylene and 13 to 20 weight percent butene-1. Such terpolymers are commercially available from Chisso under the trade name Chisso 7800 series.
    Suitable core layers of the present invention may comprise recycled polypropylene (RPP), such as up to 25 wt% RPP, preferably up to 15 wt% RPP.
    Arbitrary additives for inclusion in the core layer include glycerol or glyceride and the like, and when using them, it may be preferably 0.05 to 0.3% by weight of the layer weight, more preferably 0.1% by weight. In addition, the core layer may contain an effective amount of other suitable antistatic agents. Non-limiting examples of antistatic paper agents formulated in the core layer include tertiary amines and glycerides such as glycerol monostearate and the like. Examples of tertiary amines include N, N-bis (2-hydroxyethyl) alkenyl or mixed alkenyl amines and alkyl C 6 -C 18 cocoamines and oily amines. Examples of preferred amines include N, N-bis (2-hydroxyethyl) stearylamine, N, N-bis (2-hydroxyethyl) cocoamine or amine mixtures containing them.
    Outer layer
    The skin layer of the present invention may be any of coextruded, biaxially oriented, heat shrinkable film forming resins known in the art. Such materials are used for core layers, including isotactic polypropylene, atactic polypropylene, ethylene-propylene copolymers such as polypropylene blended with polybutene-1, propylene-butene-1 copolymers and EP copolymer fragments. The above-mentioned things are suitable. In addition, polyethylene or ethylene-propylene-butene-1 terpolymer may be used as the outer layer.
    The multilayer film of the present invention is particularly suitable for use in the tobacco industry. When used as a wrapper of tobacco packaging or tobacco cartons, these two skin layers must be weldable.
    Suitable ethylene-propylene-butene-1 random terpolymers for use in the outer skin layer of the present invention are those containing 1 to 5 wt% random ethylene, 10 to 25 wt% random butene-1. The amount of random ethylene and butene-1 components in these copolymers is typically 10-25% in total (ethylene + butene-1). Typical terpolymers of this type are those comprising 1-5% ethylene and 10-25% butene-1.
    Usually, these copolymers have a melt flow rate of 5 to 10, a density of 0.9, and a melting point of 115 to 130 ° C.
    In one aspect of the invention, the skin layer is derived from straight chain low density polyethylene (LLDPE). The melt index of these polymers is typically 1-10. Straight chain low density polyethylenes may have a density as high as 0.94, generally 0.90 to 0.91, such as 0.92 or 0.91, and a melt index of 1 to 10. Straight chain low density polyethylene can be derived from ethylene with other higher comonomers such as butene-1, hexene-1 or octene-1.
    Each skin layer adjacent the core layer may be 0.5 to 3 microns (0.02 to 0.12 mil) thick, preferably 0.5 to 1.0 microns (0.02 to 0.04 mil), such as 0.5 to 0.75 microns (0.02 to 0.03 mil).
    Prior to introduction into the film, for example prior to extrusion, one or more outer skin layers may be combined with an anti-sticking effective amount of an anti-sticking agent such as silica, clay, talc, glass, etc., wherein the anti-sticking agent is preferably in the form of approximately spherical particles. . For example, approximately 50% to 90% by weight of these particles are largely sized such that a substantial part of the surface area, such as 10 to 70%, extends beyond the exposed surface range of the skin layer. In a preferred embodiment, the anti-sticking agent comprises an insoluble silicone resin, such as particulate crosslinked hydrocarbyl substituted polysiloxane. Particularly preferred particulate crosslinked hydrocarbyl substituted polysiloxanes include polymonoalkylsiloxanes and the like. Most preferred are non-fusible polymonoalkylsiloxanes which have a three-dimensional structure of siloxane bonds with an average particle size of 0.5 to 20.0 microns. Such materials are commercially available from Toshiba Silicone Company, Limited and General Electric Company, USA, under the trade name Tospearl. Other commercially available products of suitable similar materials are known. Such materials are disclosed in US Pat. No. 4,769,418 as non-fusible crosslinked organosiloxane resin powders. The effective amount of the particulate crosslinked hydrocarbyl substituted polysiloxane anti-sticking agent may be from 100 to 5,000 ppm, preferably from 1,000 to 3,000 ppm, in particular from 2,500 to 3,000 ppm, based on the loading of the resin in which the upper layer (c) is prepared.
    The coefficient of friction (COF) and antistatic properties at the surface of the skin layer (s) can be reduced by the method disclosed in US Pat. No. 5,264,277, which discloses antistatic and mobile slip agents in multilayer films, such as erucamide. The use of is disclosed. One or two skin layers can be treated with silicone oil to reduce COF.
    An important component in the multilayer film structure illustrated herein is silicone oil. This silicone oil is incorporated into one or both of the heat sealable skin layers in an amount such that the coefficient of friction is kept low on one or both skin layers. The silicone oil is preferably added in an amount of 0.3 to 3.0% by weight and 5% by weight or less based on the weight of the outer layer.
    The silicone oil is preferably polydimethylsiloxane having a viscosity of 20,000 to 3,000,000, preferably 20,000 to 30,000 centistokes.
    The outer layer (s) may also contain up to 10% by weight of natural terpene resins or synthetic terpene resins, waxes or low molecular weight (e.g., 10,000) polyethylenes to aid thermal welding properties and improve the optical properties of the film.
    Optional additives that may be contained in the skin layer (s) include glycerol or glycerides, which may be included in the content of 0.05 to 0.3% by weight of the weight of the skin layer when used.
    If desired, the exposed surface of the skin layer (s) may be treated by known conventional methods such as corona discharge to improve suitability for subsequent manufacturing operations such as water solubility and / or lamination to printing inks, coatings, adhesive anchorages. You can.
    It is preferable to coextrude all layers of the multilayer film structure of the present invention, after which the film can be biaxially oriented (primary direction) and then the shrinkage can be secondary oriented in the desired direction. Coextrusion may be performed in a multi-layer melt form through a flat die.
    Primary orientation
    The multilayer coextrusion film is primarily biaxially oriented. The biaxially oriented film has a primary direction, preferably 3 to 8 times in the longitudinal direction, preferably 4 to 6 times in the secondary direction, preferably in the transverse direction, which is almost perpendicular to the primary direction. Can be stretched 12 times. Biaxial orientation can be performed using conventional tenter or stenter equipment at draw temperatures of 100-140 ° C., such as 130 ° C. Biaxial orientation temperatures are generally different for longitudinal orientations (115 ° C to 130 ° C, such as 120 ° C) and transverse orientations (130 ° C to 160 ° C, for example 150 ° C). In this step the film thickness can range from 25 to 75 microns (1 to 3 mils), preferably 25 to 50 microns (1 to 2 mils). The film is cooled to a temperature below 100 ° C. before the secondary orientation.
    Secondary orientation
    The primary oriented film is then reheated to 100 to 125 ° C., such as 110 to 115 ° C., preferably using a heated cylinder, and further 10 to 60%, preferably only in the primary orientation direction, eg in the longitudinal direction. Stretched 25 to 30%. Maintain a minimum distance between the reheat roll (s) and the cooling / stretching roll (s) used in the secondary orientation to minimize compressive stress that may adversely affect secondary thermal stability, such as transverse thermal stability. Good to do. Such distance may be less than 30 cm, such as 5-10 cm.
    The thickness of the uniaxial shrinkable film produced after the secondary orientation may be 10-60 microns (0.4-2.4 mil), preferably 20-40 microns (0.8-1.6 mil).
    Co-orientation
    The film of the present invention is oriented directly on a line using a linear motor to simultaneously propagate opposite pairs of tenter clips, thereby accelerating the directly opposite pairs of tenter clips supporting the film along a divergent path, resulting in simultaneous biaxial orientation. It can be manufactured by performing a primary orientation. In other words, the film can be primarily oriented by simultaneously accelerating a pair of directly opposed tenter clips supporting the film along a branching path.
    Secondary longitudinal orientation on the same line can be effected along a parallel path following a branched path by simultaneously accelerating a pair of tenter clips that are directly opposite along some section of the parallel path. In other words, the film accelerates and orients the pair of directly opposed tenter clips holding the film simultaneously along a straight path.
    The film is heated and set so that the resulting film has good longitudinal stability at temperatures below 100 ° C. and at least 25% shrinkage at temperatures above 135 ° C. in the longitudinal direction and good transverse stability at temperatures below 135 ° C., such as less than 5%. It may be further stabilized by annealing and then cooling before leaving the tenter frame.
    A method of using a linear motor that directly propels a tenter clip to perform simultaneous biaxial stretching is described in detail in US Pat. No. 4,853,602.
    The uniaxial shrinkable film produced after the secondary orientation has a thickness of 10-60 microns (0.4-2.4 mil), preferably 20-40 microns (0.8-1.6 mil).
    Dimensional stability
    The uniaxial shrinkable film produced after the secondary orientation has a shrinkage greater than 15%, preferably greater than 18%, greater than 20% and even greater than 25% in the direction of the secondary orientation, such as longitudinal, at 100-145 ° C, such as 135 ° C. Indicates. Shrinkage is determined by measuring the non-limiting sample length difference before and after placing the sample in a 135 ° C. oven for 7 minutes.
    The shrinkage in the secondary orientation direction preferably occurs with a minimum deviation in the direction perpendicular to the secondary orientation, such as in the transverse direction. This variation or stability can be explained by the change in length of the multilayer film in the direction perpendicular to the secondary orientation, and can include expansion and contraction as a percentage of dimension before thermal exposure. The film of the invention may exhibit ± 5% stability, preferably ± 3% stability or even ± 1% stability in a direction perpendicular to the direction of the secondary orientation. ± 5% stability means that after heating to 135 ° C. (275 ° F.) the dimension of the film shrinks or expands to less than 5% of the original dimension of the film at room temperature in a direction perpendicular to the secondary orientation direction.
    The films of the invention can be used in cigarette pack packaging machines such as Focke 350 or Focke 700 sold by GD4350 and GDC600 and Focke available by GC Company. While each pack is transported through the system, each pack is treated with a heat deposition site over a soak time at 1 of 1 second of moisture. The success of the operation depends on whether the packs stick together, the medium to low degree of force required to move the packs through the system, and the welding range of 20 ° F. or higher, preferably 30-40 ° F., on all deposition surfaces.
    The film of the present invention can produce a tightly packed package directly from a tobacco packaging machine. Conventional films produce a corrugated appearance, particularly at the top and base of the pack's surface. The film of the present invention greatly reduces or eliminates this problem. In addition, the film allows the cigarette pack to continue to tight over time after initial packaging to remove any wrinkles that may be generated due to the packaging machine's setup or hardbox design. This shrinkage gives the pack a surprisingly high gloss transparency.
    The invention is illustrated by the following non-limiting examples.
    Example 1
    965.75 wt% of isotactic polypropylene having high stereoregularity, 0.1 wt% of N, N-bis (2-hydroxyethyl) cocoamine, 0.1 wt% of N, N-bis (2-hydroxyethyl) stearylamine, A core layer comprising 0.05% by weight of glycerol monostearate and 4% by weight of syndiotactic polypropylene was melted and coextruded into two skin layers comprising (a) and (b) below.
    (a) an upper layer comprising 89.38 weight percent ethylene-propylene-butene-1 terpolymer, 0.31 weight percent silica antitack agent, 10 weight percent petroleum wax, 0.16 weight percent erucamide and 0.15 weight percent glycerol monostearate and
    (b) a base layer comprising 998.57 weight percent ethylene-propylene-butene-1 terpolymer, 1.2 weight percent silicone fluid and 0.23 weight percent silica anti-tack agent.
    The coextrusion was stretched 4.3 times in the longitudinal direction using a transport roll operated at various speeds. After the predetermined longitudinal orientation, the film was oriented laterally in the tenter frame. After the desired transverse orientation, the film was stretched again 15-60% or more in the longitudinal direction using a transport roll operated at various speeds. The top layer was corona treated.
    Example 2
    A core layer comprising 96% by weight of high stereoregular isotactic polypropylene and 4% by weight of syndiotactic polypropylene was melted and co-extruded into two outer skin layers comprising (a) and (b).
    (a) an upper layer comprising 89.38 weight percent ethylene-propylene-butene-1 terpolymer, 0.31 weight percent silica antitack agent, 10 weight percent petroleum wax, 0.16 weight percent erucamide and 0.15 weight percent glycerol monostearate and
    (b) a base layer comprising 98.57% by weight ethylene-propylene-butene-1 terpolymer, 1.2% by weight silicone fluid and 0.23% by weight silica tackifier.
    The coextrusion was stretched 4.3 times in the longitudinal direction using a transport roll operated at various speeds. After the predetermined longitudinal orientation, the film was oriented laterally in the tenter frame. After the desired transverse orientation, the film was again stretched in the longitudinal direction by at least 43% using a transport roll operated at various speeds. The top layer was corona treated.
    Example 3
    95.65 wt% of isotactic polypropylene having high stereoregularity, 0.15 wt% of N, N-bis (2-hydroxyethyl) cocoamine, 0.15 wt% of N, N-bis (2-hydroxyethyl) stearylamine, A core layer comprising 0.05% by weight of glycerol monostearate and 4% by weight of syndiotactic polypropylene was melted and coextruded into two skin layers comprising (a) and (b) below.
    (a) an upper layer comprising 98.57% by weight ethylene-propylene-butene-1 terpolymer, 1.2% by weight silicone fluid and 0.23% by weight silica tackifier;
    (b) a base layer comprising 98.57% by weight ethylene-propylene-butene-1 terpolymer, 1.2% by weight silicone fluid and 0.23% by weight silica tackifier.
    The coextrusion was stretched 4.3 times in the longitudinal direction using a transport roll operated at various speeds. After the predetermined longitudinal orientation, the film was oriented laterally in the tenter frame. After the desired transverse orientation, the film was stretched at least 35% in the longitudinal direction again using a transport roll operated at various speeds.
    Example 4
    A core layer comprising 96% by weight of high stereoregular isotactic polypropylene and 4% by weight of syndiotactic polypropylene was melted and co-extruded into two outer skin layers comprising (a) and (b).
    (a) an upper layer comprising 89.38 weight percent ethylene-propylene-butene-1 terpolymer, 0.31 weight percent silica antitack agent, 10 weight percent petroleum wax, 0.16 weight percent erucamide and 0.15 weight percent glycerol monostearate and
    (b) a base layer comprising 98.57% by weight ethylene-propylene-butene-1 terpolymer, 1.2% by weight silicone fluid and 0.23% by weight silica tackifier.
    The coextrusion was stretched 4.3 times in the longitudinal direction using a transport roll operated at various speeds. After the predetermined longitudinal orientation, the film was oriented laterally in the tenter frame. After the desired transverse orientation, the film was again stretched in the longitudinal direction by at least 43% using a transport roll operated at various speeds. The top layer was corona treated.
    Example 5
    95.65 wt% of isotactic polypropylene having high stereoregularity, 0.15 wt% of N, N-bis (2-hydroxyethyl) cocoamine, 0.15 wt% of N, N-bis (2-hydroxyethyl) stearylamine, A core layer comprising 0.055% by weight of glycerol monostearate and 4% by weight of syndiotactic polypropylene was melted and coextruded into two skin layers comprising (a) and (b) below.
    (a) an upper layer comprising 99.77% by weight of ethylene-propylene-butene-1 terpolymer and 0.23% by weight of a silica tackifier and
    (b) a base layer comprising 98.57% by weight ethylene-propylene-butene-1 terpolymer, 1.2% by weight silicone fluid and 0.23% by weight silica tackifier.
    The coextrusion was stretched 4.3 times in the longitudinal direction using a transport roll operated at various speeds. After the predetermined longitudinal orientation, the film was oriented laterally in the tenter frame. After the desired transverse orientation, the film was stretched at least 24% in the longitudinal direction again using a transport roll operated at various speeds. The top layer was corona treated.
    Example 6
    95.75 wt% of isotactic polypropylene having high stereoregularity, 0.1 wt% of N, N-bis (2-hydroxyethyl) cocoamine, 0.1 wt% of N, N-bis (2-hydroxyethyl) stearylamine, A core layer comprising 0.05% by weight of glycerol monostearate and 4% by weight of syndiotactic polypropylene was melted and coextruded into two skin layers comprising (a) and (b) below.
    (a) an upper layer comprising 99.77% by weight of ethylene-propylene-butene-1 terpolymer and 0.23% by weight of a silica tackifier and
    (b) a base layer comprising 98.57% by weight ethylene-propylene-butene-1 terpolymer, 1.2% by weight silicone fluid and 0.23% by weight silica tackifier.
    The coextrusion was stretched 4.3 times in the longitudinal direction using a transport roll operated at various speeds. After the predetermined longitudinal orientation, the film was oriented laterally in the tenter frame. After the desired transverse orientation, the film was stretched again 15-60% or more in the longitudinal direction using a transport roll operated at various speeds. The top layer was corona treated.
    Example 7
    95.7% by weight of isotactic polypropylene having high stereoregularity, 0.15% by weight of N, N-bis (2-hydroxyethyl) cocoamine, 0.1% by weight of N, N-bis (2-hydroxyethyl) stearylamine, A core layer comprising 0.05% by weight of glycerol monostearate and 4% by weight of syndiotactic polypropylene was melted and coextruded into two skin layers comprising (a) and (b) below.
    (a) an upper layer comprising 98.47% by weight of ethylene-propylene-butene-1 terpolymer, 1.2% by weight of silicone fluid, 0.23% by weight of silica tackifier and 0.1% by weight of insoluble silicone particles;
    (b) 98.47 wt% ethylene-propylene-butene-1 terpolymer, 1.2 wt% silicone fluid. A base layer comprising 0.23 wt% silica antitack agent and 0.1 wt% non-fusible silicon particles.
    The coextrusion was stretched 4.3 times in the longitudinal direction using a transport roll operated at various speeds. After the predetermined longitudinal orientation, the film was oriented laterally in the tenter frame. After the desired transverse orientation, the film was stretched back at least 39% in the longitudinal direction using a transport roll operated at various speeds.
    Example 8
    A core layer comprising 95.85% by weight of high stereoregular isotactic polypropylene, 0.15% by weight of N, N-bis (2-hydroxyethyl) cocoamine and 4% by weight of syndiotactic polypropylene was melted and Coextrusion was carried out to the two outer layers comprising (a) and (b).
    (a) an upper layer comprising 98.97% by weight of ethylene-propylene-butene-1 terpolymer, 0.8% by weight of silicone fluid and 0.23% by weight of a silica tackifier;
    (b) a base layer comprising 98.97% by weight of ethylene-propylene-butene-1 terpolymer, 0.8% by weight of silicon fluid and 0.23% by weight of a silica tackifier.
    The coextrusion was stretched 4.3 times in the longitudinal direction using a transport roll operated at various speeds. After the predetermined longitudinal orientation, the film was oriented laterally in the tenter frame. After the desired transverse orientation, the film was again stretched in the longitudinal direction by at least 43% using transport rolls at various speeds.
    Example 9
    This example illustrates the measurement of the adhesion of the cigarette pack of the multilayer film produced by Example 8 described above in comparison to the non-shrink film ZNA20 commercially available from Hoechst. In this example, a Kent Super Lights cigarette pack was packaged using a GDC600 Wrapper Machine commercially available from GDC Company. The adhesion of the same package peeled off from the single pack was measured three times. The adhesion measurements of the packages were measured in mm and offset from zero. Larger numbers mean a tighter package. The adhesion of the package was measured using the apparatus as described in FIG. 1. Tobacco packages were placed on fixed arms (2) and movable arms (4). The spring 6 moves the movable arm 4 to measure the width of the package from the test cigarette pack. The measurement of distance from the movable arm 4 to the micrometer 8 indicates the degree of packing. A large numerical value (in mm) means a tighter package. The measured values are shown in Tables 1 to 3 below.
    Comparative film (0.8 mil thickness)Measure 1Measure 2Measure 3 Cigarette pack number 11.271.261.25 Cigarette pack number 21.421.411.41 Cigarette pack number 31.371.371.37 Cigarette pack number 41.331.321.33 Cigarette pack number 51.391.391.39 Average value = 1.35
    Comparative Film (0.95 mil thick)Measure 1Measure 2Measure 3 Cigarette pack number 11.731.721.71 Cigarette pack number 21.541.541.54 Cigarette pack number 31.571.521.53 Cigarette pack number 41.561.541.54 Cigarette pack number 51.671.661.66 Cigarette pack number 61.581.521.52 Cigarette pack number 71.631.631.63 Cigarette pack number 81.541.541.54 Cigarette Pack Number 91.761.751.75 Cigarette pack number 101.651.651.66 Average value = 1.61
    Comparative film (0.85 mil thickness)Measure 1Measure 2Measure 3 Cigarette pack number 11.461.471.47 Cigarette pack number 21.561.551.55 Cigarette pack number 31.511.481.48 Cigarette pack number 41.481.481.48 Cigarette pack number 51.541.511.51 Cigarette pack number 61.51.521.52 Cigarette pack number 71.481.181.48 Cigarette pack number 81.551.541.54 Cigarette Pack Number 91.471.481.48 Cigarette pack number 101.51.51.51 Average value = 1.49
    Example 10
    Example 9 was repeated Example 9 using a Kent Special Milds (red ink) tobacco value and a GD4350 Wrapper Machine sold by GD Company. The measured values are listed in Tables 4 and 5 below. The average value of the measurements from Tables 1-5 is shown in Table 6 below. According to Table 6, it can be seen that a tighter packaging can be obtained using the multilayer film of the present invention.
    Comparative film (0.8 mil thickness)Measure 1Measure 2Measurement 3 Tobacco Price 10.810.810.78 Tobacco Price 20.810.810.79 Cigarette Price 30.920.910.87 Cigarette Price 40.840.840.84 Cigarette Price 50.90.890.89 Average value = 0.85
    Film of Example 8 (0.95 mil thickness)Measure 1Measure 2Measurement 3 Tobacco Price 11.461.461.45 Tobacco Price 21.471.431.42 Cigarette Price 31.431.431.42 Cigarette Price 41.411.411.42 Cigarette Price 51.451.421.41 Average value = 1.43
    summary Film typeOffset from mean 0 (mm) Table 1 (Comparative Film)1.35 Table 2 (Film of Example 8)1.61 Table 3 (Film of Example 8)1.62 Table 4 (Comparative Film)0.85 Table 5 (Film of Example 8)1.43
    It will be apparent to one skilled in the art that the specific embodiments described above can be successfully reproduced repeatedly using components corresponding to those that are generic or specifically described under various processing conditions. It will be apparent to those skilled in the art from the foregoing specification that the important features of the present invention will be readily apparent and applicable to a variety of applications without departing from the scope and scope of the invention.
    权利要求:
    Claims (12)
    [1" claim-type="Currently amended] A polypropylene-containing core layer and at least one polyolefin-containing skin layer located adjacent to the core layer, wherein the core layer contains a modifier and isotactic polypropylene that reduces the degree of crystallinity of the polypropylene-containing core layer, the skin layer A uniaxial heat shrinkable biaxially oriented multilayer film containing silver silicone oil.
    [2" claim-type="Currently amended] The method of claim 1 wherein the modifier is atactic polypropylene, syndiotactic polypropylene, ethylene-propylene copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 terpolymer, polybutene-1 and A uniaxial heat shrinkable biaxially oriented multilayer film selected from the group consisting of straight chain low density polyethylene.
    [3" claim-type="Currently amended] 3. The uniaxial heat shrinkable biaxially oriented multilayer film of claim 2, wherein the modifier comprises syndiotactic polypropylene.
    [4" claim-type="Currently amended] The uniaxial heat shrinkable biaxially oriented multilayer film of claim 1, wherein the core layer further comprises an antistatic agent selected from the group consisting of glycerides, tertiary amines and mixtures thereof.
    [5" claim-type="Currently amended] The skin layer of claim 1 wherein the skin layer is selected from one or more of the group consisting of polypropylene, ethylene-propylene copolymers, polyethylene, propylene-butene-1 copolymers, and ethylene-propylene-butene-1 terpolymers. The uniaxial heat-shrinkable biaxially oriented multilayer film whose thickness is 0.5-1.0 micron.
    [6" claim-type="Currently amended] The uniaxial heat shrinkable biaxially oriented multilayer film of claim 1, wherein the envelope layer further comprises silica and / or non-melt silicon resin.
    [7" claim-type="Currently amended] The uniaxial heat shrinkable biaxially oriented multilayer film of claim 1, wherein the envelope layer further comprises an amide of a water insoluble monocarboxylic acid.
    [8" claim-type="Currently amended] The uniaxial heat shrinkable biaxially oriented multilayer film of claim 1, wherein all of the skin layers comprise silicone oil.
    [9" claim-type="Currently amended] The uniaxial heat shrinkable biaxially oriented multilayer film of claim 1, wherein the envelope layer is corona treated or flame treated.
    [10" claim-type="Currently amended] The uniaxial heat shrinkability according to claim 1, wherein the uniaxial heat shrinkage is performed by biaxially orienting 3 to 8 times in the longitudinal direction and 6 to 12 times in the transverse direction and performing secondary alignment by further reorienting 10 to 60% in the longitudinal direction. Biaxially oriented multilayer film.
    [11" claim-type="Currently amended] The film of claim 1, wherein the film may shrink more than 15% at 100 ° C. to 145 ° C. in the first direction, and has ± 5% stability in a second direction that is substantially perpendicular to the first direction. Monoaxial heat shrinkable biaxially oriented multilayer film.
    [12" claim-type="Currently amended] The uniaxial heat shrinkable biaxially oriented multilayer film according to claim 1, which is used as a cigarette pack or a cigarette carton envelope.
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    同族专利:
    公开号 | 公开日
    CN1259099A|2000-07-05|
    WO1998056662A1|1998-12-17|
    EP1019290A4|2002-04-10|
    CA2289631A1|1998-12-17|
    EP1019290A1|2000-07-19|
    AR015871A1|2001-05-30|
    JP2002504031A|2002-02-05|
    ID22959A|1999-12-23|
    AU7500098A|1998-12-30|
    BR9809537A|2000-06-20|
    AU746233B2|2002-04-18|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1997-06-10|Priority to US87313397A
    1997-06-10|Priority to US08/873,133
    1998-05-21|Application filed by 데니스 피. 산티니, 모빌 오일 코포레이션
    1998-05-21|Priority to PCT/US1998/010348
    2001-02-26|Publication of KR20010013586A
    优先权:
    申请号 | 申请日 | 专利标题
    US87313397A| true| 1997-06-10|1997-06-10|
    US08/873,133|1997-06-10|
    PCT/US1998/010348|WO1998056662A1|1997-06-10|1998-05-21|Uniaxially shrinkable biaxially oriented polypropylene film and method for use as tobacco pack overwrap|
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