Polyolefin Composition for Multilayered and Biaxially Oriented White Appearance Opaque Films The present invention concerns the field of plastics fabrication and uses, specifically, polyolefin opaque film compositions for manufacture of biaxially oriented and multilayered films with improved properties useful for the roll- fed labelling and food, confectionary, over-wrapping, printing and lamination with various substrates, cold-seal and hot-melt applications, as well as for food packaging and other general packaging and labelling applications.

The packaging food and non-food industry, agricultural, industrial markets, decorative art, etc. has a high demand for biaxially oriented thin films of different types which can be used for the identification of various materials, for the decoration and for the provision of operating parameters and instructions, as well as for the production of labels, sheets, decals, adhesive tapes and other materials.

Opaque and white appearance films can be produced by using conventional film-forming thermoplastic polymers such as polyesters, polyamides, (metha) acrylic polymers, polyolefins, vinyl chloride polymers, styrene polymers, etc., and organic and inorganic fillers and different surface treating methods for preparation of adhesive surfaces. Many opaque appearance and heat-sealable films were produced by using conventional film-forming polymers such as polyesters, polyamides, polyolefins, vinyl chloride polymers, styrene polymers, etc., and organic and inorganic fillers (CaCO3, Ti02, etc.), and different methods for preparation of opaque and/or heat-sealable surfaces. In the earlier patent publications it was proposed to produce the multilayered and oriented opaque polypropylene-based heat-

salable and metalized films useful for the food packaging by using co- extrusion, orientation and corona discharge processing [US Pat. 4,303,708 (1981), Canada CA Pat. 9.561,125 (1974), Germany DE Pat. 2,814,311 (1979), 3,534,400 and 3.611,341 (1987), Japan JP Pat. 50-7091].

There are several patents related to polyolefin based opaque films. Thus, (1) EP-A-0 180 087 describes a five-layered salable opaque film which has a volacule-containing base layer produced from propylene homopolymer and calcium carbonate, and an intermediate layer of propylene homopolymer and hydrocarbon resin, the salable top layers of which film comprise propylene/ethylene copolymers. Because of the thick intermediate layer of polypropylene and hydrocarbon resin, the film has better mechanical properties and a higher gloss than films according to the prior art. In addition, the film can easily be corona-treated because of the sealing layers of propylene/ethylene copolymers. The film, however, is in need of improvement in respect of its antistatic properties and its destacking properties. (2) EP-A-0 312 226 discloses a multilayer opaque film in which a top layer comprises a readily printable polymer and which has an intermediate layer of propylene homopolymers and a core layer which contains volacules.

The film is said to be distinguished by a good gloss when viewed from the homopolymer side. Because of the stated ratios in layer thickness, the surface gloss and the opacity or whiteness are in need of improvement. (3) EP-A-0 408 971 describes a film of high whiteness and high opacity, which is readily printable and is said to be glossy. The film has a cloudy structure, which probably originates from the small particle size of the calcium carbonate used.

Furthermore, the increased fine content of the particles leads to a reduced opacity, since no volacules are thereby formed. (4) EP-A-0 234 758 and EP- A-0 225 685 describe readily printable opaque films. Because of the nature of the surface, however, the films are distinguished by a very matte appearance.

US 4,560,614 describes nonblocking opaque biaxially oriented polypropylene film filled with inorganic filler such as talc to prevent blocking. The film also contains Ti02 on the surface for paperlike properties.

Resulted nonblocking film has good printability, adhesion, and ink and adhesive wet out. However, said films did not contain CaCO3-based special filler in the core polyolefin layer and outer layers, and therefore did not possess pearlescent lustre and antistatic properties, and also have relatively low light transmission (25 %).

It was object of US Pat. 4,303,708 to provide opaque thermoplastic films with improved heat-sealing properties containing biaxially oriented propylene polymers such as polypropylene, ethylene (4 %)-propylene copolymer and ethylene-propylene-a-olefm (C4_o) terpolymer, finely distributed inorganic fillers (CaC03, TiOz, silicates, preferably zeolites, silica, etc.). Analogously with present invention, said opaque films contain CaC03 and TiO2 as 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 ethylene-propylene-a-olefin (C4 ln) terpolymer as a heat- sealable surface layer, organic opaque particles, which were not corona treated, and had high density (0.9 g/cm3) and relatively low output.

US Pat. 5,492,757 (1996) discloses an opaque-matte four-layer film (28 urn thickness) of A/B/C/D structure comprising (B) base layer (22.7 um thickness) from a polypropylene, 4.2-5.0 % CaCO3 filler and 3.2-8.0 % Ti02 filler, (C) interlayer (3.5 um thickness) from a 1: 1 mixture of ethylene (1. 9 %)-propylene-butylene (8.4 %) terpolymer and HDPE, (D) outer layer (0.9 llm thickness) from a said terpolymer with analogous composition and (A) outer layer (0.9 urn thickness) from a ethylene-propylene copolymer. All layers contained conventional stabilizer and neutralizer. The base layer furthermore contained aliphatic alkylamine as an 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 had matte appearance with gloss (85° angle, D side) 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 glcm3. According to this patent invention, the multilayer film 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.

Effect of interfacial interactions on the deformation and failure properties of polypropylene-calcium carbonate composites was 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 were strong. These differences were explained by the adhesion of the polymer chains to the CaC03 filler surface [B. Pukanszky, New Polym. Mater., 3,205 (1992)]. Other authors show that biaxially streching 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 stretching degree in the machine and transverse directions [Sh. Nakamura, et al., J. Appl.

Polym. Sci., 49,143 (1993)].

Multilayer polymer paper with good offset printability and pencil writability comprises a base layer from CaCO3-filled (3-35 %) stretched film of polyolefins, an inner layer from ethylene-vinyl alcohol copolymer, a top layer from inorganic-filled (8-65 %) stretched film of polyolefins, multilayer laminate with polypropylene (80 %), HDPE (8 %) and CaC03 (12 %) [Pat.

05-00490, 1993, Japan]. Mixtures of a (co) polymer of 2-6 olefin, silica (30 %), inorganic fillers (CaCO3-25 % and Ti02-5 %) and erucic amide (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, CaC03 and Ti02 and

an extruded skin layer on >1 side thereof containing styrene polymers, modified polypropylene, CaC03, TiO2, and co-and or terpolymers of ethylene [Eur. Pat. EP-A-0 605938,1994].

US Pat. 4,663,219,1987 (Siegfried J., et al., Hoechst AG, Frankfurt/Main, FRG) discloses a coextruded multilayered opaque film which has been biaxially oriented by stretching in the longitudinal (5.7-fold at 120-130°C) and transverse (10-fold at 160-170°C) directions. The film of this invention has a base layer essentially consisting of polypropylene and fillers (oxides or salts of metal-Al, Si, Ca, Ti, etc.), preferably pulverulent CaCO3 (16-30 %) with a mean size of 2-5 um. The film with 35-50 um thickness has relatively low density of 0.4-0.6 g/cm3. A least one surface layer (1 um) covering said base layer selected from the group consisting of heat-sealing (HDPE, LDPE, propylene-ethylene copolymer or propylene-ethylene-a-olefin terpolymer), cold sealing (natural and synthetic rubbers) and non-sealing (propylene homopolymer) polymers. Because of its reduced tendency to recover after folding, the film is particularly suitable for packaging purposes.

EP-A-0 538747, 1993 (Murschall, U., et al., Hoechst AG, Frankfurt Main, FRG) (this invention was also patented in other countries: US Pat. 5,366,796, DE Pat. 4135096 A, and ZA Pat. 9208204 A) discloses biaxially oriented multilayer films with high clouding and minimal shine comprising polypropylene base layer and covering layer of HDPE and ethylene, propylene and butylene copolymers. The film used as a packaging film, laminate or backing film and has high haze, minimum value of gloss and uniform mattness.

An object of the recently published US Pat. 5,876,857,1999 was a multilayered (three-layer preliminary film having a symmetric layer structure of D-top K-core D-top) and biaxially oriented opaque film which is distinguished by very good destacking properties and outstanding antistatic properties, high gloss and at least one top layer having good sealing properties. The film has a density of <0.7 and >0.58g/cm3. For opaque embodiments of the film, an outstanding opacity is desirable, and for

economic reasons, this opaque film useful for preparation of labels and/or wrappings should offer a high yield per unit area and be inexpensive to produce. The core layer of the multilayer film according to the invention essentially comprises a propylene polymer or a mixture of propylene polymers. Other suitable polyolefins in the polymer mixture include any known polyolefin, such as polyethylenes, in particular HDPE, LDPE and LLDPE, the content of these polyethylenes in each case generally not exceeding 15% by weight, based on the polymer mixture. Essentially means that the core layer generally contains at least 50%, more preferably at least 75% by weight of propylene polymers and 3-20% by weight of inorganic fillers such as A1203, A12 (SO4) 3, BaC03, CaC03 (chalk is particularly preferred), MgC03, silicates, such as aluminium silicate (kaolin clay) and magnesium silicate (talc), Si02 and/or Ti02. The film (label) comprises at least one top layer comprising a salable olefinic polymer, inorganic or organic particles (0.1-2 %) and tertiary aliphatic amine as an antistatic agent (0.05-2 %).

The prototypes of the present invention are Pat. TR 1995/00936 B and Pat. TR 98/00450 A2, Turkey (PCT/TR 99/00013,12.03.1998). The objective of said first patent invention is to design and prepare a multi-layered and biaxially oriented opaque-pearlised ! 3 layer films with given composition useful for roll-fed labelling and cold-sealable packaging materials, for food, confectionary, wrapping, printing and lamination with various substractes, and for high-speed packaging machine. This patent invention describes a multilayered and biaxially oriented polyolefin film comprising polypropylene, HDPE, LDPE, CaC03, Ti02, conventional stabilizer, antioxidant, neutralizer, antistatic, slip and antiblocking agent (synthetic silica), which are prepared by using the tandem extruder system supplied with three or four satellite co- extruders, flat die, chill roll and recycling line. Second patent invention discloses biaxially oriented polypropylene multilayer ( ! 4 layer) opaque- pearlised films with improved properties useful in addition for hot melt and

general packaging applications by using similar tandem exruder system. The films have low density (0.68 g/cm3), high mechanical properties, excellent opaque appearance, improved adhesion (65-68 kgflm2) and tear strength (16.5- 18 Nlm) toward Scotch adhesive tape (3M-USA), as well as good transfer degree of opaque layer from film to adhesive tape. The films have relatively high values of dynamic friction coefficient and heat shrinkage, low thermal stability and surface tension. The composition and properties of these films as well as their layer structure designed do not allow to prepare the white appearance opaque films with given properties. The aim of the present invention is the attempt to remove these deficiences by design of new polyolefin mutilayer compositions.

Thus, it is an object of the present invention to design and prepare multilayered and biaxially oriented polyolefin, preferably polypropylene and polyethylene mixture based white appearance opaque film compositions (Tables 1 and 2), containing given weight ratios of inorganic and/or organic filler, pigment and antiblocking agent, preferably, CaC03, Ti02 and synthetic silica, respectively, which are provided by advantageous properties as compared with known and commercial films (Table 3) allowing to use of these films for the roll-fed labelling and food, confectionary, over-wrapping, printing and lamination with various substrates, cold-seal and hot-melt applications, as well as for food packaging and other general packaging and labelling applications.

The present invention discloses a > 3 layers, preferably four layers and biaxially oriented polyolefin based white appearance opaque film composition comprising > 20 m, preferably 23-31 um multilayers from (A) 0.5 um, preferable 2-3 um white appearance opaque outer layer containing mixture of virgin or marked (5-cholesten-3p-ol as a marked agent) polyolefins, preferably mixture of polypropylene and HDPE with given composition, inorganic filler and pigment, preferably calcium carbonate as an opaque-pearlised filler and titanium dioxide as a white pigment, conventional and special stabilizer, antioxidant and neutralizer, preferably calcium stearate

as a neutralizer, tetrakis [methylene (3,5-di-tert-butyl-4-hydroxy-hydro- cinnamate] methane as a stabilizer, and allyl phosphite as antioxidant, (B) > 15 pm, preferably 17-25 urn white appearance opaque core layer containing given composition of said polyolefins, filler, pigment, stabilizer, antioxidant and neutralizer, (C) > 0.5 m, preferably 1.0-1.5 um white appearance inner layer containing given composition of said virgin or marked polypropylene, white pigment, stabilizer, antioxidant and neutralizer, and an antiblocking agent, preferably synthetic silica, and (D) ! 0.5 urn, preferably 1.0-1.5 um skin layer with composition as in (C) inner layer. These films were prepared by using the tandem extruder system supplied with two, three or four satellite co-extruders, flat die, chill roll and recycling line. After biaxially stretching (4-7 times at 100-150°C in the machine direction, MD and 9-11 times at 150- 190°C in the transverse direction, TD) and corona or polarized flame treated of one or both surfaces in the given conditions, white appearance opaque films with various total thickness had density of 0.56-0.63 g/cm2, light transmittance of 20. 3-25. 4 %, sheen of both surfaces of 34.7-38.1/39.0- 48.3 %, heat shrinkage in MD/TD of 3.3-3.6/1.8-2.1 %, friction coefficient of 0.20-0.28, tensile strength and elongation at break of 6.8-8.1 kglmm2 and 14.0-20.2 kglmm2, 101-106 % and 25-30 % in MD and TD, respectively, surface tension (after storage for 6 months) 41-54 mN/m and excellent printability, good thermal (temperature of decomposition 370-410°C ( ?) and loss weight at 400°C 5.2-16.2 % ( ?)) and dimensional stability.

According to the present invention the technological aspect of manufactured process of said films is distinguished from known processing [Pat. TR 1995/00936 B, Turkey (Polinas A. S.)] used in the production of white appearance opaque films by the fact that extruder system with two tandem main extruders supplied with two, three and four satellite co- extruders, recycling line and corona (or cold plasma) discharge or polarized flame treating system. For the polarized flame surface treatment, a Polarized Flame Treater SJ71/00 with air/gas mixture generator and polarized linear gas burner (6400 mm) system are used. The process is carried out by three chill-

roll treatments and two step of longitudinal orientation allowing to prepare good homogenized film with improving surface properties and dimensional stability. One or both surface of biaxially oriented films prepared are treated by polarized flame and/or air corona discharge in a known manner. 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 multilayer film with given composition is taken to the corresponding process steps through a chill roll and cooled, and cast film profile is controlled by-Gauge equipment. The film is subsequently stretched longitudinally at two steps and stretched transversely. After biaxially orientation, the film is thermally set and on one or two sides surface-treated. The following conditions in detail, are selected: (1) Extrusion: extrusion temperature 200-260°C, first chill roll temperature 35-45°C ; (2) Machine (longitudinal) stretching : stretching roll temperature of first step 140-150°C and second step 120-130°C, longitudinal stretching ratio 5: 1-6: 1 for first step and 1: 1-1 : 2 for second step; Transverse stretching : temperature of heat-up zones 150-165°C, temperature of stretching zones 170-190°C, transverse stretching ratio 9: 1-11: 1; Recycling : edges of the biaxially orientated film are recycled and fed to the line again; Setting : setting temperature 165-170 °C ; Air corona discharge : voltage 15-25 kV and frequency 20-30 kHz; Polarized flame treatment: Polarized Flame Treater SJ71/00 with air/gas mixture generator, polarized linear gas burner (6400 mm) and UV photoelectric eye system (special design for flame treatment of the white opaque polymer film surfaces) with the following parameters: fuel gas consumption of 13-24 NM3 Ih, inlet pressure of 100-150 mBar, treatment level of 50-55 Dynlcm, burner speed movement of 200-250 mlmin, electric supply of 380 V, 50 MHz.

Further object of the present invention is a preparation of biaxially oriented polyolefin multilayer white opaque film-forming compositions with high physical, mechanical, thermal and surface properties, excellent printability and transferring properties and good dimensional stability by variation of component and layer compositions, which allow to widen the field of

application of said films useful for the roll-fed labelling and food, confectionary, over-wrapping, printing and lamination with various substrates, cold-seal and hot-melt applications, as well as for food packaging and other general packaging and labelling applications.

Illustrated the below examples of the present invention for preparation of multilayer white appearance opaque film with different thickness, given component composition and layer structure, and improved properties.

Examples 1 and 2 Multilayer film with A/B/C/D structure (where C inner and D skin layers have similar thickness and composition) and a total thickness of 23, um comprising (A) 3.0, um opaque outer layer from 72.73 % by weight of virgin or marked (5-cholesten-3p-ol as a marked agent) polypropylene (density 0.90- 0.91 g/cm3, MFI > 1.8 g/10 min at 230°C and load at 21.6 N, m. p. 163-165 °C, vicat softening point 150-152 °C, izod impact strength 44-46 kg-cm/cm, tensile strength at break 32-34 Mpa, elongation at break 700-750 %), 12.0 % by weight of high density polyethylene (HDPE, density 0.91-0.92 g/cm3, MFI 0.3-2.0 g/10 min), 8.0 % by weight of CaCO3 as an opaque filler, 7.0 % by weight of Ti02 (rutyl) as a white pigment, 0.18 % by weight of calcium stearate as a neutralizer, 0.05 % by weight of tetrakis [methylene (3,5-di-tert- butyl-4-hydroxy-hydro-cinnamate] methane as a stabilizer, and 0.04 % by weight of allyl phosphite as antioxidant, (B) 17.0, um opaque core layer from 51.23 % by weight of said virgin or marked polypropylene, 27.0 % by weight of said HDPE, 18.0 % by weight of said filler, 3.5 % by weight of said white pigment, 0.18 % by weight of said neutralizer, 0.05 % by weight of said stabilizer and 0.04 % by weight of said antioxidant, and (D) and (C) 1.5, um white appearance inner and skin layers from 75.08 % by weight of said virgin or marked polypropylene, 24.5 % by weight of said white pigment, 0.15 % by of weight synthetic silica as an antiblocking agent, 0.18 % by weight of said neutralizer, 0.05 % by weight of said stabilizer and 0.04 % by weight of said antioxidant, was prepared by using the tandem extruder system supplied with

two, three or four satellite co-extruders, flat die, chill roll, and recycling line.

After biaxially stretching [10 times at 165°C in the transverse direction, TD and 6 times at 150°C in the machine (longitudinal) direction, MD] and air corona discharged (D layer) and/or polarized flame treated (A layer) of one or both surfaces in the given conditions white appearance opaque film has composition and properties showing in Tables 1-3, respectively.

Examples 3 and 4 A film with thickness of 27, um and given composition (Table 1), and layer composition as in Example 1 repeated with following change: (B) core layer has a thickness of 21.0, um. After biaxially stretching, setting and corona discharged in the given conditions white appearance opaque film prepared has composition and improved properties showing in Tables 1-3, respectively.

Example 5 and 6 A film with thickness of 31, um and given composition (Table 1), and layer composition as in Example 1 repeated with following change: (B) core layer has a thickness of 25.0, um. After biaxially stretching, setting and corona discharged in the given conditions white appearance opaque film prepared has composition and improved properties showing in Tables 1-3, respectively.

For analysis of the initial materials used and films prepared following known standard measurement methods are used: Specific density is determined in according to ISO 1183 and/or ASTM D- 1505.

Melting Flow Index (MFI) is measured in according to ASTM 1238/L at 230°C and load of 21.6 N.

Melting point (m. p.) is measured by DSC method, maximum point of the melting curve, at heating rate 10°C/min is corresponded to m. p. value.

Vicat softening point is determined in according to ASTM D-1525.

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

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

Adhesion and tear strength of films toward acrylic adhesive tape (Adhesin J 1610) are determined by using INSTRON Testometer with specimen dimensions 2.5x15 cm.

Transfer de¢ree of opaque laver from film to said adhesive tape is calculated by using of tear strength data and changes of film weight after testing.

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

Dvnamic friction 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 45°.

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.

Thermal stabilitv (temperature of decomposition and loss weight at given temperature) of the film is measured by using Thermal Gravimetric Analysis (TGA 2050) method.

Surface tension of the film after surface ionization by air corona discharge (plasma) and/or flame (polarized flame) treatment after storage for 6 months is measured in accordance with ASTM D-2578. Table 1. Polyolefin compositions for white appearance opaque films (invented and known films for the comparison) Components of Films Composition (%) and total thickness (hum) Known Films of white appearance opaque films (PCT/TR 99/00013) E1 E2 E3 E4 E5 E6 23pm 23µm 27µm 27µm 31µm 31µm 27µm 31µm Polypropylene (marked or virgin) 55.90 56.29 56.25 56.67 55.60 55.95 79.49 79.57 High density polyethylene (HDPE) 22.66 22.85 22.34 22.54 22.94 23.12 8.56 8. 73 Low density polyethylene (LDPE)------0. 80 0. 68 Calcium carbonate 15. 11 15.23 14.90 15.03 15.30 15.41 8.85 9. 00 (opaquefuller) Titanium dioxide (white pigment) 6.04 5.34 6.22 5.47 5.87 5.23 1.82 1.58 Synthetic silica (antiblocking agent) 0.02 0.02 0.02 0.02 0.02 0.02 0.15 0. 13 Ethoxylated amine------0. 05 0. 04 (migratory antistatic agent) Calcium stearate (neutralizer) 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 Allyl phosphite (antioxidant) 0.04 0.04 0.04 0.04 0.04 0.04 0.05 0.04 Tetrakis [methylene (3,5-di-tert- 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 butyl-4-hydroxy-hydrocinnamate] methane(stabilizer)

Table 2. Layer compositions of white appearance opaque films (invented and known films for the comparison) Example Composition (%) and thickness (, um) of each layer No Outer layer A Core layer B Inner layer C Skin layer D E1-E2 3.0 zm 17 um 1.5 µm 1.5µm 23 pm *Polypropylene 73.00 Polypropylene 51.50 Polypropylene 75. 35 Polypropylene 75.35 (total HDPE 12. 00 HDPE 27. 00 Ti02 24.50 Ti02 24.50 thickness) CaC03 8.00 CaC03 18.00 Synthetic silica 0.15 Synthetic silica 0.15 TiO2 6.00 Ti02 3.50 E3-E4 3. 0 µm 21 µm 1.5 µm 1.5 µm zip Polypropylene 73.00 Polypropylene 51.50 Polypropylene 75.35 Polypropylene 75.35 (total HDPE 12. 00 HDPE 27. 00 TiO2 24.50 Ti02 24.50 thickness) CaC03 8.00 CaC03 18.00 Synthetic silica 0.15 Synthetic silica 0.15 TiO2 6.00 TiO2 3.50 E5-E6 3. 0 µm 25 µm 1.5 Mm 1. 5Hm 31 u. m Polypropylene 73.00 Polypropylene 51.50 Polypropylene 75. 35 Polypropylene 75.35 (total HDPE 12.00 HDPE 27.00 TiO2 24.50 Ti02 24.50 thickness) CaC03 8.00 CaC03 18.00 Synthetic silica 0.15 Synthetic silica 0.15 TiO2 6.00 TiO2 3.50 Known 0. 5-1.2 urn22. 8-31. 2 um 1.5 urn1. 5 km Films *Polypropylene 69.50 Polypropylene 80.16 Polypropylene 78.65 Polypropylene 78.65 27-35 lem LDPE 6.00 HDPE 9.84 LDPE 6.00 LDPE 6. 00 (total CaC03 8.00 CaCO3 10.00 Ti02 14.00 TiO2 14.00 thickness) TiO2 14.00 Synthetic silica 1.35 Synthetic silica 1. 35 Ethoxylated amine 2.50

* Polypropylene (used in the both invented and known film layers of A/B/C/D structure) contains given amount of a special marked agent, conventional neutralizer, stabilizer and antioxidant, as well as special antioxidant (for invented films using for the food packaging application). Table 3. The properties of white appearance opaque films of present invention and known films Properties E1 E2 E3 E4 E5 E6 Known & Comm Films Total thickness (, um) 23 23 27 27 31 31 27 31 Yield (m/kg) 69.0 65.9 61.7 60.7 55.6 57.6 57.0 49.6 Specific density (g/cm) 0. 63 0.62 0.60 0.61 0.58 0.56 0.65 0.65 Light transmission (%) 25.2 25.4 24.5 23.0 22.8 20. 3 28.6 29. 3 Seen (gloss), 45° (%) (A) outer layer surface 36.7 36.0 38.1 35.9 35.8 34.7 44.2 43.5 (D) skin layer surface 49.0 48.3 47.2 39.0 40.6 40.0 41.6 52.2 Heat shrinkage (%) at 120°C, 15 min, in MD 3.5 3.6 3.5 3.5 3.3 3.6 3.0 3.0 in TD 2.0 2.0 2.0 2.0 1.8 2.1 1.0 1.0 Coefficient of friction Film/Film 0.22 0.21 0.26 0.20 0.24 0.21 0.20 0.24 Film/Metal 0.25 0.24 0.28 0. 23 0.28 0.23 0.24 0.26 Tensile strength at break (kg/mm2) in MD 6.8 6.9 7.6 8.1 7.5 7.6 7.5 7.5 in TD 14.0 14.0 15. 2 20.2 19.4 20.0 13.8 16.8 Elongation at break (%) in MD 101 103 104 105 106 105 105 105 in TD 26 25 28 30 27 30 30 30 Adhesion (kgf/m2) 72.1 70. 6 69.0 70.3 71.0 69.0 68.0 67.0 Tear strength (N / m) 19.5 20.0 18.7 19.2 19.0 18.0 18.0 16.0 Transfer degree of opaque layer (%) 10.6 11.3 12.3 12.0 12.0 11.8 9.5 9.2 Oxygen permeability (cm3 I m2 24 h-atm) 4600 4500 4600 4500 4550 4500 4000 4000 Water vapour transmission (g/m2. 24 h) 4.0 4.0 3.5 3.5 4.0 3.5 3.5 3.5 Surface tension (after storage for 6 months) (mN/m), corona 41 41 41 41 41 41 40 39 polarized flame 53 52 52 54 52 53--