Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J123/00—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers
  • C09J123/02—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers not modified by chemical after-treatment
  • C09J123/18—Homopolymers or copolymers of hydrocarbons having four or more carbon atoms
  • C09J123/20—Homopolymers or copolymers of hydrocarbons having four or more carbon atoms having four to nine carbon atoms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/38—Pressure-sensitive adhesives [PSA]
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
  • C08L2666/02—Organic macromolecular compounds, natural resins, waxes or and bituminous materials
  • C08L2666/04—Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L57/00—Compositions of unspecified polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C08L57/02—Copolymers of mineral oil hydrocarbons
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/14—Layer or component removable to expose adhesive
  • Y10T428/1452—Polymer derived only from ethylenically unsaturated monomer

Definitions

• the present invention relates to a pressure sensitive adhesive composition
• a pressure sensitive adhesive composition comprising butene-1 (co)polymers (homo or copolymers) and multilayer easy peel re-closable structures with butene-1 (co)polymers in the reclosable pressure sensitive adhesive layer.
• the present invention relates to multilayer easy peel re-closable structures providing a heat seal peelable and re-closable between substrates, such as a rigid container and a peelable lid, or a flexible film package made from films and/or laminates.
• substrates such as a rigid container and a peelable lid
• flexible film package made from films and/or laminates.
• PVC polyvinyl chloride
• the present invention is preferably directed to rigid containers or flexible film packages requiring sealability on polyolefin polymers, preferably propylene or polyethylene polymers substrates.
• the seals can be formed over a wide range of heat seal temperatures and are easily peelable.
• the seal strength must be adequate to maintain the package in a closed and protective condition, while also exhibiting such release properties as will permit opening by peeling when desired.
• reclosable refer to the ability of the substrate and lid or of the laminates in the film package to be re-closed after the first peeling providing again a seal strength adequate to maintain the package in a closed and protective condition till a second and further opening.
• peelable refers to a seal failure which occurs primarily at the interface of the sealing surfaces, rather than by film tearing.
• Tacky pressure-sensitive adhesive are known in the art for use in reclosable structures.
• PSA Tacky pressure-sensitive adhesive
• WO 0245949 it is disclosed the generic principle of heat sealability and reclosability in multilayer structures a specifically described an easy-to-open and reclosable heat sealing material comprising an adhesive reclosable layer.
• an adhesive reclosable layer is disclosed made of an hot melt adhesive composition comprising a styrenic resin (at least 30wt% SIS or SBS resin) at least 50% of a tackifier, at least 6% of a reinforcing filler component ad at most 7% wt of a plasticizer.
• US 2007/0082161 disclose a packaging article comprising a peelable resealable multilayer film comprising at least three polymer layers.
• the films comprise a peelable resealable interface adapted to reseal after separation. The force to "reseal" the interface is proportional to the manual pressure exerted on the film.
• the second polymer layer in US 2007/0082161 is a pressure-sensitive adhesive comprising a tackifier first component and an elastomer second component of styrene/rubber copolymer
• the third polymer layer preferably includes a material selected from the group consisting of ethylene/vinyl alcohol copolymer, polyester, polyketone, polystyrene, acrylic ester- based polymer, cyclic olefin copolymers, methylpentene homopolymer or copolymer, polyamide, and blends thereof.
• PB-1 copolymer as component of the tacky pressure-sensitive adhesive in the second (internal) polymer layer.
• tackifier is generally an adhesive additive which serves to modify the rheological properties of the final adhesive. Specifically, a tackifier resin is used to improve the tack of the adhesive composition. As used herein, the term “tack” refers to the "stickiness" of the adhesive or its resistance to removal or deformation from a substrate.
• the tackifier may comprise any suitable material, preferably, a resin or hydrocarbon resin material or mixtures thereof.
• tackifiers among the hydrogenated hydrocarbon resins, are those having melting temperature equal to or higher than 100°C, more preferably higher than 110°C providing improved reclosability.
• reclosability refers to the number of effective reclosures and level of re-open peel strength (force) measured after reclosure on a multilayer easypeel reclosable structure according to the invention.
• more than one reclosure should be possible, more preferably at least 5 reclosure cycles; and preferably the reopen peel force is higher than 0.1 N, preferably higher than 0.5 N.
• a pressure sensitive adhesive essentially consisting of a polyolefin composition, particularly suitable for use in easy peel reclosable structures comprising a specific butene-1 (co)polymer as major component providing optimal balance of heat seal strength and reclosability and suitability for use in food contact applications.
• the pressure sensitive adhesive of the invention further comprises at least one tackifier.
• the said tackifier being capable of further improving the reclosability of a pressure sensitive adhesive layer according to the invention.
• the tackifier when present can be used in reduced amount with respect to the known pressure sensitive adhesive compositions typically based on styrenic resins.
• the PSA compositions according to the invention provide an alternative to the styrenic rubbers known in the art as polymeric component to be used in pressure sensitive adhesives for tacky reclosable layers in easy peel reclosable structures.
• Heat seal reclosable multilayer films according to the present invention can be formed by coextrusion of at least three separate polymer layers using either cast or blown film coextrusion methods.
• a pressure-sensitive adhesive substantially consisting of a polyolefin composition, comprising
• butene-1 derived units 80wt% or more, preferably of 84wt% or more
• Tml melting temperature DSC
• tackifier preferably the tackifier is a "Hydrogenated Hydrocarbon Resin".
• the pressure-sensitive adhesive polyolefin composition comprises:
• Component (A) and (B) can be for example melt blended directly in a co-extrusion process or blended and pelletized to be subsequently used in a co-extrusion process.
• the butene-1 (co)polymer (A) used as the major component for the preparation of pressure sensitive adhesive (PSA) compositions according to the present invention is typically exhibiting from elastomeric to plastomeric behaviour and can be a homopolymer or a copolymer of butene- 1 with one or more a-olefins (different from butene-1).
• Particularly preferred as comonomer is ethylene.
• the butene-1 (co)polymer (A) suitable for the use according to the invention has a low crystallinity of less than 40% measured via X-ray, preferably less than 30% even more preferably lower than 20%
• the butene-1 (co)polymer has a density of 0.899 g/cm 3 or less, more preferably of 0.895 g/cm 3 or less, even more preferably lower than 0.875.
• the butene-1 (co)polymer has hardness shore A lower than 90, more preferably lower than 70.
• the butene-1 (co)polymer has a distribution of molecular weights (Mw/Mn) measured by GPC lower than 4
• the butene-1 (co)polymer as no melting temperature (Tmll) DSC, measured after cancelling the thermal history of the sample, according to the DSC method described herein below in the experimental part.
• Tmll melting temperature
• the butene-1 (co)polymer (A) is preferably selected from the group consisting of:
• isotactic pentads from 10% to 50%, preferably from 10% to 40%
• (A2) a butene-1 homo or copolymer, preferably a butene-1 /ethylene copolymer or a butene-1 /ethylene/propylene terpolymer having the following properties:
• Mw/Mn molecular weights measured by GPC equal to or lower than 3, preferably from 2 to 3;
• the butene-1 (co)polymer (Al) is preferably an homopolymer or a copolymer having a content of comonomer derived units from 1 to 15% by mol.
• the preferred alfa olefin comonomers are ethylene and propylene.
• the butene-1 (co)polymer (Al) can be obtained contacting 1 -butene and optionally one or more alpha olefins, under polymerization conditions, in the presence of a Ziegler Natta catalyst system comprising:
• the polymerization temperature is generally comprised between -100°C and +200°C, preferably from 20 to 120°C, more preferably from 40 to 90°C, most preferably from 50°C to 80°C.
• the amount of comonomers was calculated from C- NMR spectra of the copolymers of the examples. Measurements were performed on a polymer solution (8-12 wt%) in dideuterated 1 ,1 ,2,2-tetrachloro-ethane at 120 °C. The 13 C NMR spectra were acquired on a Bruker AV-600 spectrometer operating at 150.91 MHz in the Fourier transform mode at 120 °C using a 90° pulse, 15 seconds of delay between pulses and CPD (WALTZ16) to remove 1H- 13 C coupling. About 1500 transients were stored in 32K data points using a spectral window of 60 ppm (0-60 ppm).
• the melting enthalpy after 10 days and the melting temperature of crystalline form I (Tml) was measured as follows by using the Differential Scanning Calorimetry (D.S.C.) on an Perkin Elmer DSC-7 instrument: A weighted sample (5-10 mg) obtained from the polymerization was sealed into aluminum pans and heated at 200°C with a scanning speed corresponding to 20°C/minute. The sample was kept at 200°C for 5 minutes to allow a complete melting of all the crystallites. The sample was then stored for 10 days at room temperature. After 10 days the sample was subjected to DSC, it was cooled to -20°C, and then it was heated at 200°C with a scanning speed corresponding to 10°C/min. In this heating run, the first peak temperature coming from the lower temperature side in the thermogram was taken as the melting temperature (Tml), and the area as global melting enthalpy after 10 days ( ⁇ ).
• D.S.C. Differential Scanning Calorimetry
• microstructure analysis was carried out as described in literature (Macromolecules 1991, 24, 2334-2340, by Asakura T. et Al. . and Polymer, 1994, 35, 339, by Chujo R. et Al.).
• K RB is the constant of the copolymer
• K PE (4.06 x 10 ⁇ 4 , dL/g)
• K PB (1.78 x 10 ⁇ 4 dL/g)
• X E and X B are the ethylene and the butene wt% content.
• the Mark-Houwink exponents 0.725 was used for all the butene/ethylene copolymers independently on their composition.
• Table 1 is reporting the structures and properties of butene-1 (co) polymers according to the invention (Al type and A2 type) and comparatives
• PB1 is a butene-1 homopolymer (type Al) obtained by polymerization of the monomers in the presence of a low stereospecificity Ziegler-Natta catalyst and process as described in the international application WO2006/042815.
• the external donor used to decrease further the stereoregulating capability of the catalyst to obtain a polymer of the Al type of the present invention was the external donor 3,4-dimethoxy-toluene.
• PB1 polymerization was carried out in a liquid-phase stirred reactor in which liquid butene-1 constituted the liquid medium.
• the Solid Catalyst Component had been prepared in advance into a 500 ml four-necked round flask, purged with nitrogen, 225 ml of TiC14 were introduced at 0 °C. While stirring, 6.8 g of microspheroidal MgC12 » 2.7C2H50H (prepared as described in Ex. 2 of USP 4,399,054 but operating at 3,000 rpm instead of 10,000 rpm) were added. The flask was heated to 40°C and 4.4 mmoles of diisobutylphthalate were thereupon added. The temperature was raised to 100 °C and maintained for two hours, then the stirring was discontinued, the solid product was allowed to settle and the supernatant liquid was siphoned off.
• the catalyst component contained 2.8 wt% of Ti and 12.3 wt% of phthalate.
• PB2 and PB4 are butene-1 /ethylene copolymers (type A2) produced according to the process described in WO2004/099269 and WO2009/000637.
• PB3 was obtained from PB2 by in-line compounding a crystalline low sit terpolymer (ii) added in amount of 7 wt% with respect to the weight of the (co) polymer composition
• the butene-1 (co)polymers (A) were used as such (examples 4-9 in table 3) or melt blended with the tackifiers in amount as indicated in table 2 examples 1 -3.
• the resultant compositions of examples 1-9 were pelletized and dried with use of commercial additives, antisticking agents to improve flowability and contributing to the handability of the compositions. Finishing treatments lead to a total amount of additives in the final pellets typically Less than 1.0 wt%, preferably less than 0.5wt% even more preferably less than 0.2wt% (about 100-1500 ppm per additive or less). Examples of such finishing treatments can be found in the international patent application PCT/EP2010/056159.
• Blown films have been prepared by extruding each test composition and the polymers for the external layers in a single screw Dr. Collin extruder equipped with a three layers co-extrusion blown film line at a melt temperature of 210-215 °C.
• the throughput was about (abt.) 20 kg/h.
• the extruder was equipped with an annular die with a diameter 80 mm and having a die gap 1.2 mm.
• the films were cooled by mean of a dual flow cooling ring with cooling air at ambient temperature.
• the bubble was layed-flat and winded at a film drawing speed of 9 m/min.
• the films were produced with a bubble wall thickness of 55 ⁇ , which is the final specimen thickness obtained.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Laminated Bodies (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Adhesive Tapes (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)

Priority Applications (6)

Applications Claiming Priority (4)

Publications (1)

Family

ID=44802079

Family Applications (1)

Country Status (7)

Cited By (11)

Families Citing this family (15)

Citations (14)

Family Cites Families (8)

• 2011
  • 2011-10-18 JP JP2013534292A patent/JP6005649B2/ja active Active
  • 2011-10-18 WO PCT/EP2011/068177 patent/WO2012052429A1/en not_active Ceased
  • 2011-10-18 BR BR112013009717-5A patent/BR112013009717B1/pt active IP Right Grant
  • 2011-10-18 CN CN201180050171.XA patent/CN103154176B/zh active Active
  • 2011-10-18 US US13/880,403 patent/US9284475B2/en active Active
  • 2011-10-18 KR KR1020137009674A patent/KR101958495B1/ko active Active
  • 2011-10-18 EP EP11770463.5A patent/EP2630211B1/en active Active

Patent Citations (14)

Non-Patent Citations (6)

Also Published As

Similar Documents

Legal Events