AU772959B2 - Biaxially oriented polypropylene multilayer opaque-pearlised films with improved properties - Google Patents

Description

WO 00/56547 PCT/TR99/00013 BIAXIALLY ORIENTED POLYPROPYLENE MULTILAYER OPAQUE-PEARLISED FILMS WITH IMPROVED PROPERTIES The present invention concerns the field of plastics fabrication and uses, specifically, biaxially oriented polypropylene multilayer opaque-pearlised films with improved physicomechanical properties.

The packaging food and non-food industry, agriculture, industrial markets, art, etc. has a high demand for biaxially oriented thin films of different types such as opaque, matte, colorless, antifog, antibacterial, photosensitivity, biodegradable, heat-sealable, non heat-sealable, monoand multilayer, laminated, metallizated and other films and materials.

Opaque appearance films can be produced by using conventional filmforming polymers such as polyesters, polyamides, polyolefins, vinyl chloride polymers, styrene polymers, etc., and organic and inorganic fillers (CaCO 3 TiO 2 etc.), and different methods for preparation of opaque surfaces.

In the earlier patent publications it was proposed to produce multilayer oriented opaque polypropylene-based heat-sealable and metalized films useful for the food packaging by using co-extrusion, orientation and corona-discharge processings [Pat. US 4303708, 1981, USA, Pat. CA 956125, 1974, Canada- Pat.

DE 2814311, 1979, 3534400, 3538101 and 3611341, 1987, FRG; Pat. 50-7091, Japan].

There are a number of patents which can be considered to be analogous to the present invention [Pat. US 4560614, 1985; Pat. EP 0317276 BI, 1994; Pat.

US 4303708 (Hoechst Aktienizesellsschaft), FRG]. Thus, Patent US 4560614 describes nonblocking opaque biaxially oriented polypropylene film filled with inorganic filler such as talc to prevent blocking. The film also contain TiO2 on the surface for paperlike properties. Resulted nonblocking film have good printability, adhesion, and ink and adhesive wet out. However, said films did not contain CaCO 3 -based special filler in the core polypropylene layer and antistatic WO 00/56547 PCT/TR99/00013 agent in the skin layers, and therefore did not possess pearlecent lustre and antistatic properties, and also have relatively low fight transmission (25 Patent EP 0317276 B I describes biaxially oriented polypropylene film with good crease and twist retention containing 15 of a-methylstyrene-vinyltolueneindene terpolymer and/or organic (polyester or polyamide) and inorganic (CaCO 3 BaSO 4 talc, etc.) fillers, conventional antistatic and/or slip agents and organosilicon surfactant.

It was object of patent US 4303708 to provide opaque thermoplastic films with improved heat-lealing properties containing biaxially oriented propylene polymers such as polypropylene, ethylene(4 %)-propylene copolymer and ethylene-propylene-a-olefi (C 4 -10) terpolymer, finely distributed inorganic fillers (CaCO 3 TiO 2 silicates, preferably zeolites, silica, etc.). Analogously with present invention, said opaque films contain CaCO 3 and TiO 2 as a fillers and silica as an antiblocking agent. However, said films were prepared in sheet of tubular form and were contained ethylene-propylene copolymer as a based layer and ethylenepropylene-c-olefm (C4-10) terpolymer as a heat-sealable layer, organic opaque particles, which were not corona-treated, and had high density (0.9 glcm 3 and relatively low output, and also had not antistatic and slip properties.

Recently published Pat. 5492757, USA (1996) discloses a opaque-matte four-layer film (28 pm thickness) of A/B/C/D structure comprising base layer (22.7 gm thickness) from a polypropylene, 4.2-5.0 CaCO 3 filler and 3.2-8.0 TiO 2 filler, interlayer (3.5 pmn thickness) from a 1:1 mixture of ethylene(I.9 %)-propylene-butylene (8.4 terpolymer and HDPE, outer layer (0.9 pm thickness) fiom a said terpolymer with analogous composition and outer layer (0.9 pm thickness) a ethylene-propylene copolymer. All layers contained conventional stabilizer and neutralizer. The base layer furthermore contained aliphatic alkylamine as antistatic agent. After co-extrusion, extruded four-layer film was taken off a first take-off roll and further trio of rolls. The film was then cooled, subsequently stretched longitudinally and transversely, set and corona treated. The films resulted has matte appearance with gloss (850 angle, D side) WO 00/56547 PCT/TR99/00013 29-84, coefficient of friction 0.4-0.6, whiteness (D side) 65-81, opacity (D side) 67-70 and density 0.69-0.94 The multilayer film according to this patent invention was distinguished by a multiplicity of advantageous properties and was recommended for wide variety of applications such as an attractive matte lamination film, an opaque packaging film in high-speed packaging machines, an opaque film in wrapping film. and a base film for adhesive tape or for aqueous barrier coating systems. The film was also suitable for the production of plastic labels and laminates with paper, cardboard, metals, and metalized plastic films.

Biaxially oriented polypropylene opaque film with 44 pm thickness is prepared by use cyclopentadiene based petroleum resins with softening point 160-230 0 C as an opaque filler and have average transmission of 22 against for a film containing a petroleum resin with Ts, 145 0 C instead [Pat. 04-20542, 1992,Japan].

Effect of interfacial interactions on the deformation and failure properties of polypropylenecalcium carbonate composites were studied. It was shown that changing interaction exerted widely differing influence on the different properties; modulus was hardly influenced by it, while the dependence of yield and failure properties was strong. These differences were explained by the adhesion of the polymer chains to the CaCO 3 filler surface [B.Pukanszky, New Polym. Mater., 3, 205 (1992)]. By other authors shown that biaxially stretching of polypropylene sheets containing CaC03 filler results in microporous sheets that feel soft and dry.

Their properties depend on filler content, particle size of the filler, and stretching degree. It was shown that mechanical properties of films are controllable by adjusting streching degree in the machine and transverse directions [Sh.

Nakamura, et al. JAppL Polym. Sci., 49, 143 (1993)].

Polypropylene resin compositions containing calcium silicate and calcium carbonate (40-60 as a filler had good tapping characteristics, mechanical properties, and processabihty surface [Pat. 04-306247, 1992, Japan].

Antifogging polyolefin composition useful for molding films used in packaging photosensitive materials comprises a mixture of ethylene(3.2 %)-propylene WO 00/56547 PCT/TR99/00013 random copolymer (60 and ethylene (21 %)-propylene block copolymer (38.9 oleic amide as a lubricant (0.1 glycerol monostearate as a dripproofing agent (0.2 dibenzyhdene sorbitol as an organic nucleating agent CaCO 3 (0.2 and TiO 2 (0.3 as an inorganic nucleating agents, phenolic and phosphor-containing antioxidants (0.2 [Eur. Pat. EP 524404, 1993)].

Multilayer polymer paper with good offset printability and pencil writability comprise a base layer from CaCO 3 -filled (3-35 stretched film ofpolyolefins, an inner layer from ethylenevinyl alcohol copolymer, a top layer from inorganicfilled (8-65 stretched film of polyolefins, multilayer laminate with polypropylene (80 HDPE (8 and CaCO 3 (12 [Pat. 05-00490, 1993, Japan]. Mixtures of a (co) polyiner of C 2 -6 olefin, silica (30 inorganic fillers (CaCO 3 -25 and TiO 2 -5 and erucamide (5 extruded to give a film useful as a paper substitute and packaging [Pat. BE 1004565, 1992, Belgium].

Oriented polypropylene synthetic paper with good ink receptivity and opacity having suitable writability and printing properties comprises an extruded core layer from polypropylene, CaCO 3 and TiO 2 and an extruded skin layer on I side thereof containing styrene polymers, modified polypropylene, CaCO 3 TiO 2 and co- and/or terpolymers of ethylene [Eur. Pat. EP 605938, 1994].

The prototype of the present invention is Pat. TR 97/00058 Al, 1997 (Turkey). This patent describes biaxially oriented polypropylene opaquepearlised films, process for their manufacture and use of films. Title multilayer films with 20-60 gm thickness, high yield (51-62 m 2 lkg), low density (0.62-0.65 g/cm 3 and relatively good phisico-mechanical properties (light transmission 33 heat shrinkage in machine direction-NM 3.0-3.5 and in transverse direction-TD 1.0-1.5 tensile strength at break 6-8 and 15-18 kglmM2 in NM and TD, respectively, dynamic friction coefficient 0.25-0.30, water vapour transmission 3.5-4.0 g/m 2 -24 h, oxygen permeability 2100-2500 cm 3 /m 2 -24 -24 h-atm and wetting tension 38-42 dyne/cm), specially useful for roll-fed labelling and food, confectionery, cold-seal and heatsealable packaging materials as well as for high-speed packaging machine, comprising virgin and/or marked WO 00/56547 PCT/TR99/00013 polypropylene (0.01-0.001 of 5-cholesten-30-ol as a tracer agent), LDPE, HDPE, white pigment (TiO2), pearlised filler (CaCO3), and conventional antistatic, slip and antiblocking agents were prepared by using the tandem extruder system supllied with three independent co-extruders, and air coronadischarge. 'bifference and deficiency of these films as compared with films of present invention are following: multilayer films non contain an outer layer comprising virgin or marked polypropylene, LDPE, CaCO 3 TiO 2 calcium stearate as a neutralizer, tetrakis [methylene (3,5-di-tert-butyl-4-hydroxy-hydrocinnamate] methane (TM) as a stabilizer, allyl phosphate (APH) as antioxidant, and ethoxlated amine (EtA) as an antistatic agent, and have relatively high density and low phisico-mechanical properties, as well as low values of adhesion and tear strength toward Scotch adhesive tape and low transfer degree of opaque layer from film to said adhesive (Tables I and The aim of the present invention is the attempt to remove these deficiences.

Thus, it is an object of the present invention to design and prepare a multilayer structure for biaxially oriented polypropylene based opaque-pearlised film in addition containing outer layer with given composition (Table 3) which is provided advantageous properties as compared with known and commercial films.

The present invention describes a four-layer biaxiafly oriented polypropylene opaque pearlised films having advantageous properties such as dimensional stability, low density, high adhesion, tear strength, tensile strength and elongation at break, and high surface tension after storage for 6 months. The films of the present invention as compared with commercial opaque film also have advantageous properties (Tables I and 2).

According to the present invention the technological aspect of manufactured process of said films is distinguished from known processing [Pat.

TR 97/00058 Al, Turkey] used in the production of opaque-pearlised films by the fact that tandem extruder system with two main extruders supplied with three satellite co-extruders, recycling line and corona discharge. The process is carried out by three chill-roll treatments and two step of longitudinal orientation allowing WO 00/56547 PCT/TR99/00013 to prepare good homogenized matte film with improving surface properties and dimensional stability. One or both surface of biaxially oriented films prepared are treated in a known manner by air corona discharge. The use of said recycling line for film waste forming in the transverse stretching stage allows to lower film cost by 3.5 After coextrusion, the extruded five-layer film is taken off over the corresponding process steps through a chill roll and cooled, and cast film profile is controlled by P-Gauge equipment. The film is subsequently stretched longitudinally at two steps and stretched transversely. After biaxially orientation, the film is set and air corona-treated on one or two sides. The following conditions in detail, are selected: Extrusion: extrusion temperature 200-260 0

C,

first chill roll temperature 35-45C; Machine (longitudinal) stretching: stretching roll temperature of first step 140-150°C and second step 120-130 0

C,

longitudinal stretching ratio 5:1 6:1 for first step and 1: I 1:2 for second step; Transverse stretching: temperature of heat-up zones 150-165 0 C, temperature of stretching zones 170-180 0 C, transverse stretching ratio 9:1 10:1; Recycling: edges of the biaxially orientated film is recycled and fed to the line again; Setting: setting temperature 165-170OC; Air corona discharge: voltage 15-25 kV and frequency 20-30 kHz.

It is further object of the present invention to widen the field of application of said films useful for roll-fed labelling and food, confectionary, overwrapping, printing and lamination with various substrates, cold-seal and hot melt applications, high speed packaging machines, and for general packaging applications. The following Examples of the present invention for preparation of multilayer opaque-pearfised films with different composition, improved properties are illustrated.

WO 00/56547 PCT/TR99/00013 Example I A/B/C/D structure multilayer film with a thickness of 27,um comprising 1.2 upm outer layer from 69.37 by weight of polypropylene (density 0.90- 0.91g/cm 3 3-6 g/ 10 min at 230°C and load at 21.6 N, m.p. 163-165 vicat softening point 150-152 0 C, izod impact strength 44-46 kg-cm/cm, tensile strength at break 32-34 Mpa, elongation at break 700-750 6 by weight of low density polyethylene (LDPE, density 0.91-0.92 g/cm 3 WI 0.3-2.0 g/1O min), 8 by weight of CaCO 3 14 by weight of TiO2 (rutyl), 0.05 by weight of calcium stearate as a neutralizer, 0.04 by weight of tetrakis [methylene butyl4-hydroxy-hydro-cinnamate] methane (TM) as a stabilizer, 0.04 by weight of allyl phosphate (APH) as antioxidant, and 2.5 by weight of ethoxylated amine (EtA) as an antistatic agent, 22.8 pm core layer from 79.87 by weight of virgin and/or marked polypropylene (5-cholesten-30-ol as a marked agent), high density polyethylene (HDPE, density 0.950- 0.965 glCM3, NEI 3.5-3.8 gllO miti, m.p. 134-136'C, vicat softening point 128-130'C, izod impact strength 35-37 kg-cmlcm, tensile strength at break 28-30 Mpa, elongation at break 500-600 by weight of CaCO3, 0.2 by weight of calcium stearate, 0,05 by weight of TM stabilizer and 0.04 by weight of APH antioxidant, 1.5 mu inner layer from 78.22 by weight of polypropylene, 6 by weight of LDPE, 14 by weight of TiO2, 0.05 by weight of calcium stearate, 0.04 by weight of TM stabilizer, 0.04 by weight of APH antioxidant and 1.35 by weight of synthetic silica (SS) with particle size of 2-4 pun as an antiblocking agent, and (D) pm skin layer with composition as in inner layer, was prepared by using the tandem extruder system supplied with three or four satellite co-extruders, flat die, chill roll, and recycling fine. After biaxially stretching [10 times at 165 'C in the transverse direction, TD and 6 times at 150 0 C in the machine (longitudinal) direction, NM] and air corona discharged of one or both surfaces in the given conditions opaque-pearlised film has composition and properties showing in Tables 1-4, respectively.

WO 00/56547 PCT/TR99/00013 Example 2 The film a thickness of 27 pm and A/B/C/D structure and composition as in Example I repeated with following changes: outer layer have a thickness of 0.8 pm and core layer have a thickness of 23.2 pm. After biaxially stretching, setting and corona discharged in the given conditions 0. 8 pm 23.2 pm 1. pm 5 pm film prepared has properties showing in Tables I and 2.

Example 3 The film a thickness of 27 pm and A/B/C/D structure and composition as in Example 1 repeated with following changes: outer layer have a thickness of pm and core layer have a thickness of 23.5 Ian. After biaxially stretching, setting and corona discharged in the given conditions 0.5 pm 23.5 pn 1.5 pm pm film prepared has properties showing in Tables I and 2.

Example 4 The film a thickness of 31 pm and A/B/C/D structure and composition as in Example I repeated with following changes: outer layer have a thickness of 0.

8 pm and core layer have a thickness of 27.2 pm. After biaxially stretching, setting and corona discharged in the given conditions 0. 8 pm 27.2 pm 1. 5 pm 1. 5 tm film prepared has properties showing in Tables I and 2.

Example The film a thickness of 31 pm and A/B/C/D structure and composition as in Example 1 repeated with following changes: outer layer have a thickness of pm and core layer have a thickness of 27.5 pm. After biaxially stretching, WO 00/56547 PCT/TR99/00013 setting and corona discharged in the given conditions 0.5 pm 27.2 pm 1.5 pm pm film prepared has properties showing in Tables I and 2.

Example 6 The film a thickness of 35 upm and A/B/C/D structure and composition as in Example I repeated with following changes: outer layer have a thickness of pm and core layer have a thickness of 27.5 pm. After biaxially stretching, setting and corona discharged in the given conditions 0.5 upm /27.5 um 1.5 pm 1.5 pm film prepared has properties showing in Tables I and 2.

For analysis of the initial materials used and films prepared following known standard measurement methods are used: S pecific density, is determined in according to ISO 1 1 83 and/or ASTM D- 1 505.

Melting Flow Index (WI) is measured in according to ASTM 1238/L at 2300C and load of 21.6 N.

Melting point is measured by DSC method, maximum point of the melting curve, at heating rate 1 O'Clmin is corresponded to m. p. value.

Vicat softenin. point is determined in according to ASTM D- 1 525.

Izod impact stretsth is measured in according to ISO 180/1 A.

Tensile strength and elongation at break are determined in according to ASTM D-882.

Adhesion and tear strength of films toward scotch adhesive tape (3M-USA) are determined by using INSTRON Testometer with specimen dimensions 2.5 x cm.

Transfer degree of opaque layer from film to said adhesive tape is calculated by using of tear strength data and changes of film weight after testing as a function of outer skin layer's delamination property.

Light transmission (haze) of the film is measured in accordance with ASTM D- 1003.

WO 00/56547 PCT/TR99/00013 Dynamic fi-iction coefficient of the film is determined in accordance with ASTM D-1984. Sheen of the film is measured in accordance with ASTM D-2103, the angle of incidence is set at 450.

Shrinkage of the film is measured in accordance with ASTM D-1204. The test sample is shrink at 120'C for a period at 15 min.

Surface tension of the film after surface ionization by air corona discharge and after storage for 6 months is measured in accordance with ASTM D-2578.

Oxy en Permeability of the film is measured in accordance with ASTM D-1434.

Water Vapour Transmission of the film is measured in accordance with ASTM E-96.

WO 00/56547 PCT/TR99/00013 Table 1. Thne Contrison of some properzes of present invention &nd known (or curnner.-iai) opaque-peauiised BOPP ELilms Properties Opaqu e-pearl ised BOPP films of Filmrs El E2 E3 Known Pat.* Commercial)I Total thickness (pwn) 27 27 27 2 7 27 Th~ickness of outer A laver c(on) 1.2 0.8 0.5 0.8 Adhesion (kg m) 55.5 64r.9 68.0 61.4 60.3 Tear Strength 12.0 16.5 18.0 12.3 11.4 Transfer dearee of opaque layer 3.2 7.5 9.5 1.21 *Pat. TR 97/00058 Al, 1997 (Polias WO 00/56547 PCTTRM99/00013 Table 2. Physico-mechanical properties opaque-pearlised films Properties El E2 E3 E4 ES E6I Known Film Total thickness (,am Thickness of A-layer (an) Yield (m 2 /kg) Specific density g cm 3 Light transmission Sheen (gloss), 450 outer layer surface skin layer surface Heat shrinkage at 120"C, inMD inTD Coefficient of friction Film/Film Film/Metal Tensile strength at break (kg mm 2 in MD inTD Elongation at break (kg/mm 2 inMD in TD Adhesion (kg/I m 2 Tear strength (N/r Transfer degree of opaque layer Oxygen Permeability cm 3 m 2 .24 h-aim Water Vapour Transmission (g m 2 .24 h Surface tension (after storage for 6 months) mN/m 27 1.2 61.6 0.63 26.9 34 45 3.0 1.0 27 0.8 62.0 0.63 27.5 32 44 3.0 1.0 27 0.5 63.4 0.63 27.0 33 44 3.1 1.2 31 0.8 51.0 0.65 28.2 32 43 3.5 1.5 31 0.8 51.0 0.63 28.6 31 42 3.4 1.4 35 0.8 53.3 0.62 29.3 32 43 3.2 1.2 0.20 0.21 0.20 0.22 0.24 0.23 0.22 0.25 0.24 0.25 0.26 0.25 6.9 7.1 7.5 7.5 7.2 7.5 15.9 14.6 13.8 16.8 18.0 18.0 27 0.8 62.0 0.65 33.0 0.30 0.25 15.0 100 61.4 12.3 1.2 4500 38 95 25 55.5 12.0 100 28 64.9 16.5 100 30 68.0 18.0 105 30 66.0 17.5 105 30 67.0 16.8 3.2 7.5 9.5 8.6 9.2 7.9 4500 4500 4500 4000 4000 4000 4.0 39 4.0 4.0 3.5 3.5 3.5 40 40 41 41 40 WO 00/56547 PCT/TR99/00013 Table 3. Compositions ofopaque-pearibsed BOPP films of present invention Composition Opaque-pearlised BOPP films with different thickness* of BOPP Films El E2 E3 E4 E5 E6 Known Films 27pn 27m 27jm 31/A= 3LnB 35/sn 27anl 31/Aw 3Son Polypropylene 79.25 79.38 79.49 79.45 79.57 79.51 82.00 80.19 80.12 (virgin or marked) HDPE 8.31 8.45 8.56 8.64 8.73 8.77 6.58 8.40 8.56 LDPE 0.93 0.85 0.80 0.75 0.68 0.65 1.05 0.58 0.51 Calcium carbonate 8.80 8.85 8.85 8.98 9.00 9.10 7.90 8.92 9.05 Titanium dioxide 2.18 1.98 1.82 1.72 1.58 1.52 2.40 1.35 1.20 Synthetic silica 0.15 0.15 0.15 0.13 0.13 0.12 0.03 0.14 0.13 Calcium stearate 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 Allyl phosphite 0.04 0.04 0.05 0.04 0.04 0.04 0.06 0.07 Ethoxylated amine 0.11 0.07 0.05 0.06 0.04 0.06 0.04 0.12 0.11 Tetrakismethane 0.05 0.05 0.05 0.05 0.05 0.05 0.06 0.07 Thickness of outer A layers: 1.2 0.5(E3) and 0.8 .n (E2 and E4-E6).

WO 00/56547 PCT/TR99/00013 Table 4. Layer compositions of opaque-pearlised BOPP films of present invention Exam La yer ty es pies Outer layer A Core layer B Inner layer C Skin layer.D 1.2 jim 22.8 jm 1.5 pzm 1.5 jm PP 69.37%0/6, LDPE PP 79.87 HDPE PP 78.22 LDPE PP 78.22 LDPE El 6 CaCO 3 8.0 9.84 CaCO310 TiO 2 14%, CaSt 60/, TiO2 14, CaSt iOz 14%, CaSt 0.05 CaSt 02 TM 0.05 SS 1.35 0.05 SS 1.35 0.04%, EtA 2.5 0.05 AF 0.04 TM 0.04 AF 0.04 TM 0.04%, AF 0.04 AF 0.04 0.8 Lm 23-2 um 15 um 1.5 ur PP 69.37 LDPE PP 79.87 HDPE PP 78.2 LDPE PP 78.22 LDPE E2 6 CaCO3 8.0 9.84 CaCO 3 10 TiO 2 14%, CaSt TiOi 14%, CaSt TiO2 14%, CaSt 0.05 CaSt 0.2 V, TM 0.05 0 A, SS 1.35 0.05 SS 1.35 0/, TM 0.04%, EtA 2.5 0.05 O/o,AF 0.04 TM 0.04 AF 0.04 TM 0.04%, AF 0.04 AF 0.04 urn 23.5 ur 1.5 srn 1.5 um PP 69.37 LDPE PP 79.87 HDPE PP 78.22 LDPE PP 78.22 DPE E3 6%Oh, CaCO 3 8.0 9.84 CaCO 3 10 TiOz 14%, CaSt TiO 2 14%, CaSt TiO 2 14%, CaSt 0.05 CaSt 0.2 TM 0.05 SS 1.35 0.05 SS 1.35 TM 0.04%. EtA 0.05 AF 0.04 TM 0.o4 AF 0.04 TM 0.04%, AF 0.04 AF 0.04 0.8 um 27.2 um 1.5 um 1.5 rm PP 69.37 LDPE PP 79.87 HDPE PP 78.22 LDPE PP 78.22 LDPE E4 6 CaCO 3 8.0 9.84 CaCO 3 10 fl02 14%, CaSt TiO 2 14%K, CaSt TiO 2 14%, CaSt 0.05 CaSt 0.2 TM 0.05 SS 1.35 0.05 O/ SS 1.35 TM 0.04%, EtA 2.5 0.05 %,AF 0.04 TM 0.049%, AF 0.04 TM 0.04%, AF 0.04 AF 0.04 jim 27.5 1m .j m 1.5 pim PP 69.37 LDPE PP 79.87 HDPE PP 7812 LDPE PP 78.22 LDPE ES 6 CaCO 3 8.0 9.84 CaCO 3 10 TriO 14%, CaSt TiO 2 14%, CaSt Ti2 14%, CaSt 0.05 CaSt 0.2 TM 0.05%ch, SS 1.35 0.05 SS 1.35 TMO0.04%, EtA 2.5 0.05 0/,AF 0.04 TM 0.04%, AF 0.04 TM 0.04%, AF 0.04 AF 0.04 0.8 pLm 31.2 g m 1.5 jCzm 1.5 pm PP 69.37 LDPE PP 79.87 HDPE PP 78.22 LDPE PP 78.22 DPE E6 6 CaCO 3 8.0 9.84 CaCO 3 10 M0O 14%, CaSt TiO2 14%, CaSt TiO 2 14%, CaSt 0.05 CaSt 0.2 TM 0.05 SS 1.35 0.05 SS 1.35 TM 0.04%, EtA 2.5 0.05%, AF 0.04 TMo.04 %,AF0.04% TM0.04%,AF0.04 AF 0.04

Claims (4)

1. A four-layer A/B/C/D structure biaxially oriented polypropylene opaque- pearlised film with thickness of 20-60 un comprise 0.5-5 pm outer layer containing polypropylene, low density polyethylene (LDPE), CaCO 3 TiO2 (rutyl), calcium stearate as a neutralizer, tetrakis [methylene (3,5-di-tert-butyl-4-hydroxy- hydro-cinnamate] methane (TK as a stabilizer, allyl phosphate (APH) as antioxidant, ethoxylated aniine (EtA) as an antistatic agent, 18.5-45, mn core layer containing virgin and/or marked polypropylene (5-cholesten-30-ol as a marked agent), high density polyethylene (HDPE), CaCO 3 calcium stearate, TM stabilizer and APH antioxidant, 0.5-5 pm inner layer and 0.5-5 pm skin layer containing polypropylene, LDPE, TiOz, calcium stearate, TM stabilizer, APH antioxidant and synthetic silica (SS) with particle size of 2-4 pr as an antibolcking agent, respectively, was prepared by using the tandem extruder system supplied with three or four satellite co-extruders, flat die, chill roll, and recycling line. After biaxially stretching [10 times at 165C in the transverse direction, TD and 6 times at 150'C in the machine (longitudinal) direction, NM] and air corona discharged of one or both surfaces in the given conditions opaque- pearlised film has a dimensional stability, a density of less than or equal to about 0.65 g/cm 3 an adhesion of less than or equal to about 68 kgf/m 2 and a tear strength of less than or equal to about 18 Nim toward scotch adhesive tape, a transfer degree of opaque layer from film to scotch adhesive tape of less than or equal to about 9.5 a tensile strength at break of less than or equal to about and 18.0 kg mm 2 in machine and transverse directions, respectively, an elongation at break of less than or equal to about 105 and 30 in machine and transverse directions, respectively, an oxygen permeability of less than or equal to about 4500 cm 3 /m 2 .24 h-atm, a water vapour transmission of less than or equal to about 4.0 g m 2 .24 h and a surface tension (after storage for 6 months) of less than or equal to about 41 mN/m. WO 00/56547 PCT/TR99/00013

2. A film according to claim 1 contained 0. 5-1.2 pn thickness of outer layer comprising a mixture of polypropylene, LDPE, CaCO 3 TiO 2 calcium stearate as a neutralizer, tetrakis [methylene (3,5-di-tert-butyl-4-hydroxy-hydro- cinnamate] methane (TM) as a stabilizer, allyl phosphate (APH) as antioxidant, ethoxylated amine (EtA) as an antistatic agent.

3. A film according to claim 1 have high adhesion of less than or equal to about 68 kg/m 2 and tear strength of less than or equal to about 18 N/m toward scotch adhesive tape, and good transfer degree of opaque layer from film to scotch adhesive tape of less than or equal to about 9.5

4. A film according to claim 1 have high tensile strength at break of less than or equal to about and elongation at 7.5 and 18.0 kg /mm in machine and transverse directions, respectively, break of less than or equal to about 105 and 30 in machine and transverse directions, respectively. The films according to claims 1-4 are recommended for roll-fed labelling and food, confectionery, overwrapping, printing, and lamination with various substrates, cold-seal and hot melt applications, high speed packaging machines, and for general packaging applications.