EP1005420A1

EP1005420A1 - Biaxially oriented polypropylene based matte-translucent multilayer films, process for their production and the use thereof

Info

Publication number: EP1005420A1
Application number: EP98939044A
Authority: EP
Inventors: Cumhur BÜYÜKAKINCI; Turgut Selbasti; Zakir Rzaev; Ekrem Karpat; Oktay Aral; Özlem VATANSEVER
Original assignee: Polinas Plastik Sanayi VE Ticaret AS
Current assignee: Polinas Plastik Sanayi VE Ticaret AS
Priority date: 1997-08-11
Filing date: 1998-08-10
Publication date: 2000-06-07
Also published as: TR199700780A2; TR200000421T2; WO1999007553A1; AU8755098A; TR199700780A3; WO1999007553A9

Abstract

Biaxially oriented multilayer matte-translucent film useful for photographic paper laminations, reproduction pictures and menu coatings, conventional lamination purposes, hygienic applications, health care products, food stuffs packaging, cosmetics and picture frames, high speed packaging machines, and as matte tape base films, and for general packaging and overwappring applications, comprising 15-50 νm≤5 layers from (A) 1.5-3.0 νm skin matte-translucent layer containing ethylene(E)-propylene(P)-butylene(B) terpolymer with E-unit content of 1.5-4,9 % and B-unit content of 5,5-15 % polypropylene, high density polyethylene (HDPE) and/or 10:(0.5-1.5) mixture or blend of HDPE with polymethyl(metha)acrylates, alternating or random copolymer of vinyl monomer (styrene, alkyl(metha)acrylates, etc.) or α-olefins (C2-10) with anydrides or esters of unsaturated mono- or dicarbonic acids as matting agent, synthetic silica as an antiblocking agent, erucicamide as a slip agent and allyl phosphite (APH) as antioxidant, calcium stearate as a neutralizer, and tetrakis [methylene(3,5-di-tert-butyl-4hydroxy-hydro-cinnamate] methane as a stabilizer, (B) ≥0.5 νm polypropylene inner layer containing said APH antioxidant, stabilizer, neutralizer and/or slip agent, and/or ≥1.5 νm inner layer with composition as a (A) matte layer (C) 10-46 νm virgin or marked polypropylene core layer containing 5-cholesten-3β-ol as a marked agent, saids APH antioxidant, stabilizer and neutralizer, and/or said slip agent and ethoxylated amine as an antistatic agent, (D) ≥1.5 νm poilypropylene inner layer containing said APH antioxidant, stabilizer and neutralizer, and (E) ≥0.5 νm outer shining layer containing polypropylene, said antiblocking agent, APH antioxidant and neutralizer, and/or ≥1.5 νm outer matte layer with composition as a (A) layer, were 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 and air corona discharged in the given conditions matte-translucent film has sheen (angle 85°) of 10-15 (skin matte side) and 42-61 (outer shining side), longitudinal shrinkage of ≥0.5 % at 90 °C, and ≥2.5 % at 120 °C and transverse shrinkage of $m/G)0.25 % at 90 °C, and ≥1.5 % at 120 °C for a period at 15 min, excellent matte appearance, surface tension of 40-41 mN/m (after storage for 6 months), high dimensional stability, and low heat sealing temperature of ≤110 °C.

Description

BIAXIALLY ORIENTED POLYPROPYLENE BASED MATTE- TRANSLUCENT MULTILAYER FILMS, PROCESS FOR THEIR PRODUCTION AND THE USE THEREOF

The present invention concerns the field of plastics fabrication and uses, specifically, biaxially oriented polypropylene multilayer matte-translucent films. 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 matte, colorless, antifog, antibacterial, photosensitivity, biodegradable, heat- sealable, non heat-sealable, mono- and multilayer, laminated, metallizated and other films and materials. The status of the development of the packaging technology using polyolefins, further prospects for using polyolefins in the composition of packaging films, advantageous properties and economic aspects of application of biaxially oriented polypropylene films were the object of discussion of several articles and International Conference on polypropylene [Clancioto R., Packaging (USA), 1989-supρl.:encycl.-C, 29-31; Jhaveri R., CEW: Chem. Eng. World, 24(9), 37(1989); Isaka T., Kobunshi, 41(6), 402 (1992); Chem. Abstr., 118, 214372b (1993); Int. Conf. on Polypropylene-the way ahead, Madrid, 9-10 Nov., Prepr.- London, 1989].

Matte appearance films can be produced by using conventional film-forming polymers such as polyesters, polyamides, polyolefins, vinyl chloride polymers, styrene polymers, etc. and different methods for preparation of matte surfaces.

Matte surface film for artist's overlays comprises a translucent polymer base film coated with a dried film of matting lacquer comprising: (1) a film-forming plastic resin on the base of styrene-maleate resin and ethyl cellulose, (2) a polystyrene, polyester and polyvinylchloride base film, (3) a relatively soft matting agent - non elastomeric polyethylene particles, (4) relatively hard matting agent such as silica and calcium carbonate, and (5) a mixture of organic solvents [Pat. 4719141, USA (1988)].

Several early patents comprise matted biaxially oriented polyethylene terephtalate film preparing by using water, matting solution (10-20 %) of diethylene glycol-ethylene glycolterephtalic acid copolymer in formal glycol, mixture of melamine resin and silicic acid, 2,4-dichlor-6-hydroxy-_?-triazine (0.05 %) in water, and also polystyrene [Pat. 434094, SU (1974), Pat. 265855, SU (1976), Pat. 301841, SU (1976), Pat. 49-132166, Japan (1974)]. For example, polyethylene terephtalate (PET) film with a matte surface for drawing office applications containing polystyrene (1-20 %) and TiO (1-10%) as a filler was biaxially oriented at 105-110 degree by stretching. The material prepared has 60-

65 % transmission and a pencil line on it has density of 0.7-0.8 g/cm³ [Pat.

434094, SU (1974)].

Matte surface polymer film useful for preparation of drawing papers, magnetic recording tape leader, wallpaper, capacitor insulators, labels, etc., were prepared from polyester-PET (80 parts), polystyrene (10 parts) and polymethylmethacrylate (10 parts) by stretching 150 % mono- or biaxially and optionally, laminated on one side of the polyester films. The film obtained has good mechanical strength and writing ability [Pat. 63-193920, Japan (1974)]. Matte polyamide film contains itaconic acid-methyl acrylate-vinylidene chloride terpolymer (0.1-10 parts) as a matting agent ands have good antiblocking properties without sacrificing heat sealability [ Chem. Abstr., 80 (12), 6065 lz].

Biaxially stretched anisotropic films comprising ethylene-propylene copolymer or blends of polypropylene and polyethylene (1-10 %) were prepared by extruding at 260°C and sprayed onto a casting roll at 30°C, stretched longitudinally 5.6 times at 145°C and transversely 9.3 times at 157°C [Pat. 1936963, Germany (1971)].

New film developments by using modern manufacturing processes such as stenter or flat die and bubble or tubular processes and productivity improvements were allowing biaxially oriented polypropylene films to pierce through new markets as replacement for conventional flexible packaging materials such as paper, aluminium foil, and other plastic films (PET, PA, PVC, LDPE, HDPE, cellulose, etc.).

Several patent publications relate to polyolefin (homo- and copolymers of propylene with α-olefins) based multilayer transfer metallization films, including also matte and/or opaque appearance films [Pat. 63-73146 (Japan), Pat. EP-A-O 175259 and EP-A-O 352463, Pat. Appl. 95 / 936 (Turkey), Pat. 4135096

(Germany), Pat. 88048244 (UK) and 88199666 (UK)]. Thus, Pat. 4135096 (Germany) comprises a multilayer matte appearance film containing a polypropylene based layer and an outlayer made from an HDPE and propylene homo-, copolymer and terpolymer blends which has minimum sheen and maximum haze.

Mitsubishi Royan Co., Ltd. the process for producing of translucent polypropylene monolayer film was patented [Pat. 41-38520, Japan (1979)]. Other recently publication Japan patent relates to a matte packaging film comprising polypropylene and Al borate as translucency-providing agent which was prepared from mixture of 90 parts of polypropylene and 10 parts of Alborex Y (AL borate whisker) by extruding through a temperature-die. The translucent film with 30 μm thickness have an adequate surface unevenness [Pat. 06-212037, Japan (1994)].

The object of Pat. EP-A-O 367613 was a multilayer film containing a vacuole polypropylene base layer and an incribable outer layer made from a mixture or blend of HDPE with polyolefins. The title film has a density of 0.69 g/cm³, opaque appearance and non-transparent to light properties. Additionally, it was preferred to incorporate a SiO₂-filler into the outer layer to improve the incribability. This layer was also very matte, which gives the film a paper-like appearance. Therefore, SiO₂ containing matte surface proves to be unsatisfactory on the printing.

Biaxially oriented multilayer ( < 3 layers) polyolefin films including polypropylene and HDPE, and having low coefficient friction, excellent optical transparency, good wettability, high sheen and low haze were invented in the patents of 4419411 (USA), 4578316 (USA) and 89/10839 (WO). The object of Pat. 5478643, USA (1995) was a 21.5 μm thickness matte multilayer (< 3 layers) polypropylene film for use in a metallization process which contains one base polypropylene layer (19 μm thickness) with migrating additives such as N,N-bis-hydroxyethyl) (C_{10- 0})alkylamine (0.22 %) and stearamide (0.25 %) and each outer layer (1.25 μm thickness) including a mixture or blend of polypropylene, ethylene-propylene copolymer and/or ethylene-propylene-butylene terpolymer, and HDPE, blend of HDPE with said propylene copolymer or terpolymer. This outer layer was distinguished by a characteristic matte surface or appearance and was suitable for use as a transfer metallization film. All layers of said film contained 0.12 % by weight of pentacrythrityl tetrakis[4-(3,5-di-tret- butyl-4-hydroxyphenyl) propionate] as a stabilizer and 0.05 % by weight of calsium stearate as a neutralizer. The film resulted was then co-extruded the melts corresponding to the individual layers through a flat-film die, taked the film off over a take-off roll at 40-100°C, biaxially stretched at a longitudinal stretching ratio about 4:1 to 7:1 and a transverse stretching ratio about 8:1 to 10:1, heat setting and corona treated (one or both outer layer). The film prepared has following average characteristics: thickness 10-50 μm, density 0.90-0.92 g/cm³, sheen (85° angle) 29-42, haze 52-70 %, roughness 2.3-3.2 μm, coefficient of friction 0.3-0.5, surface tension (after storage for 6 months) 38-39 mN/m, and very good matte appearance (visual assessment). Similarity of said patent with the present invention that the film consists HDPE, polypropylene and ethylene- propylene-butylene terpolymer; the film in the both cases have a matte appearance. Difference and deficiency of said film are the following: the film mainly were recommended for use in metallization process; co-extruder system used allows only to prepare maximum 3-layer film; the film not contains a matting agent such as a carbonyl containing alternating or random copolymer, and also have comparative high values of sheen, and low values of surface tension (Table 1).

Pat. 5489454, USA (1996) describes a biaxially oriented, shrinkable, heat- sealing 3-layer (10-50 μm thickness) polyolefin film with a matte appearance, good passage through the machine and antistatic and shrink properties, which simultaneously forms very tight, effective bil-low- and fold-free wrapping, and also was provided a co-extruding process for its production. In order to improve the specific properties of these polyolefin films both the base layers (polypropylene or polypropylene mixture) and outer layer(s) (mixture or blend of propylene copolymer or terpolymer and HDPE) contain 0.1-0.2 % SiO , CaCO₃ and/or incompatible organic polymers such as polyamides, polyesters, polycarbonates, benzoguanamine-formaldehyde resins as antiblocking agents, 0.05-2.0 % phenolic stabilizers, 0.05-0.25 % high aliphatic acid amide and polydimethyldisiloxanees as lubricants, 0.05-0.3 % glycerol monostearate as antistatic agent. The film resulted was stretched in the longitudinal direction preferably from about 4:1 to 9:1 at 80-120°C and in the transverse direction from about 6:1 to 8:1 at 130-155°C. The films with different compositions has the following characteristics: sheen (85° angle) 30-38, haze 62-68 %, roughness 2.6- 3.0 μm, coefficient of friction 0.3-0.4, surface tension 39 mN/m, minimum heat- sealing temperature 105-115°C, longitudinal and transverse shrinkage at 90°C 4- 6 % and 3-5 % at 120°C 11-14 % and 16-20 % respectively. Similarity is in the fact that the use in film composition of propylene homo- and terpolymer, and HDPE; difference and deficiency are the following: the films contained SiO₂, CaCO₃ and/or said incompatible organic polymers as matting and antiblocking agents and have comparative high values of sheen, and longitudinal and transverse shrinkage and low values of surface tension (Table 1).

Three early patents (DE-A 1694694, US 4419411 and EP-A 008904) were related to biaxially oriented polyolefin multilayer films having good heat-sealing on the both sides. However, these films has low surface and mechanical properties, and also unsatisfactory processing properties in high-speed packaging machines.

Recently published Pat. 5492757, USA (1996) discloses a opaque-matte four- layer film (28 μm thickness) of A/B/C/D structure comprising (B) base layer (22.7 μm thickness) from a polypropylene, 4.2-5.0 % CaCO₃ filler and 3.2-8.0 % TiO₂ filler, (C) interlayer (3.5 μm thickness) from a 1:1 mixture of ethylene(1.9 %)-propylene-butylene(8.4 %) terpolymer and HDPE, (D) outer layer (0.9 μm thickness) from a said terpolymer with analogous composition and (A) outer layer (0.9 μm 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 (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 %. 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. The comprise of properties these films with properties of films according to present invention (Table 1) shown that the films of said invention have high value of gloss of matte side. The film contain only HDPE as matting agent and terpolymer with E- and B-units differing from composition of terpolymer using in present invention.

High shrinkage polyolefin multilayer films were disclosed in the following early patent publications: EP-A-O 436196, EP-A-O 350859, DE-A 1954467 and DE-A 3215120. The films according to these patents has very high sheen values and very low haze. Therefore these shrink films were unsatisfactory with respect to their passage through the machines, and their properties during winding, further processing and slitting.

Pat. 5494717, USA (1996) relates to a biaxially oriented matte polypropylene film of high shrinkage which comprises a three-layers of X/ZX structure, i.e., one base layer Z containing a polypropylene or propylene polymer mixture and two outer layers X containing mixture or blend of polypropylene, ethylene-propylene copolymer ethylene-propylene-butylene terpolymer and HDPE. In order to improve specific properties of films both the base and outer(s) layers include conventional additives such as known antiblocking and antistatic agents, stabilizers, neutralizers and lubricants. High shrinkage, uniform matte appearance, good passage through the machine, good antistatic properties and high suitability for rolling up of films resulted allow to use as film packaging for books, frames, toys, food stuffs, cosmetics, etc., and also for metallization and lamination after corona or flame treatment. The films prepared after biaxially oriented and corona treated has sheen 29-40 (85° angle), has 58-70 %, roughness 2.3-3.2 μm, coefficient of friction 0.3-0.5, surface tension 38-39 mN/m, longitudinal and transverse shrinkage at 120°C 29-36 % and 41-47 % respectively.

Analogously with present invention homo- and terpolymer of propylene, HDPE, antiblocking agent and neutralizer are used in the composition of corona-treated biaxially oriented films. The films of present invention as compared with matte film of said patent have advantageous properties (Table 1).

The object of several patent publications [EP-A-O 479101, EP-A-O 432452 and DE-A 3535472] was multilayer transparent twist wrapping films made from mono- and/or biaxially balanced oriented propylene polymer and copolymers. Thus, Pat. EP-A-O 479101 (1992) discloses a biaxially oriented polypropylene film (25 μm thickness) for twist-wrapping which was prepared from mixture of isotactic polypropylene (71.6 %), hydrogenated cyclopentadiene resin with softening point 140°C (28 %), ethoxylated amine (0.2 %) as an antistatic agent, erucicamide (0.2 %) as a slip agent, and polydimethylsiloxane (0.5 %) as a surfactant by co-extruding and drawn longitudinally 6.5 -fold at 110°C and transversely 7.3 -fold at 150°C. After corona treatment said film had surface tension 40 mN/m, and elastic modulus 3200 and 3400 N/mm , tensile strength 20.9 and 21.9 kgl/mm , elongation 95 and 78 %, shrinkage 11 and 7 % in the longitudinal and transverse directions, respectively. Similarity is in the fact that corona treated biaxially oriented polypropylene film contains antiblocking agent; difference and deficiency of this film as compared with films of present invention are following: non-filled transparent films contain polydimetylsiloxane as surfactant, and hydrogenated cyclopentadiene resin and have relatively low elongation and high values of shrinkage. These twist wrapping films has unsatisfactory appearance, processing properties and in particular scratch resistance. The aim of Pat. 5496600, USA (1996) was the attempt to remove these deficiencies. Said patent describes a three-layer biaxially oriented polypropylene matte film having advantageous properties such as a characteristic matte sheen at less than 80, very good printability and twist properties, uniform matte appearance and excellent scratch resistance and using as a twist wrapping film. The title film contains homo-, co- and terpolymer of propylene, and HDPE or blend of HDPE with said polyolefins, and also petroleum, terpen and other hydrocarbon resins, including dicyclopentadiene polymer, as amorphous matting agents. The film also has a permanent set of greater than about 50 %, in the longitudinal and transverse directions and approximately isotropic mechanical properties. Heat-setting, biaxially stretched and corona treated film has overall thickness 10-80 μm, density 0.90-0.95 g/cm³, sheen 29-42, has 58-70 %, roughness 2.3-3.2 μm, coefficient of friction 0.3-0.5, surface tension 38-39 mN/m, permanent set 62-64 % and 60-63 % in the longitudinal and transverse directions respectively, and scratch resistance (Δhaze) 20-22. However, these films as compared with films of present invention have high sheen of matte side, and high values of longitudinal and transverse shrinkage at 120°C (Table 1).

The films of present invention as compared with commercial matte film also have advantageous properties (Table 1).

Thus, it is an object of the present invention to design and prepare a multilayer structure for biaxially oriented polypropylene based matte-translucent films with high sheen, excellent matte appearance surface, lower longitudinal and transverse shrinkage for dimensional stability, low heat sealing temperature, low water absorption, good lay-flat characteristics, for dimensional stability, resistance to oil, crease and chemicals.

One object of the present invention is to improve the production process of said films by using tandem extruder system supplied with three co-extruders, recycling line for the film forming in the transverse stretching stage and corona discharge, and also modified variant of chill-roll treatments of films in the biaxially orientation process allowing to form homogen matte films with improved surface properties and dimensional stability. Another aspect of the present invention to use new polymer system, i.e. mixture or blend of HDPE with carbonyl containing homo- and copolymers such as polymethyl(metha)acrylates, alternating or random copolymers of vinyl monomers or -olefins (C₂-ιo) with anhydrides or esters of unsaturated mono- or dicarbonic acids as mattering agent in the skin matte layer of said films.

It is further object of the present invention to winden the field of application films prepared useful for photographic paper laminations, reproduction pictures and menu coatings, conventional lamination purposes, hygienic applications, health care products, food stuffs packaging, cosmetics and frames, high speed packaging machines, and as matte tape base films, and for general packaging and overwrapping applications. An offered A/B/C/D/C multilayer film of the present invention is biaxially oriented matte-translucent polypropylene based film structure comprising 15-50 μm < 5 layers from (A) Pat. < 3.0 μm skin matte-translucent layer containing ethylene(E)-propylene(P)-butylene(B) terpolymer with E-unit content of 1.5-4.9 % and B-unit content of 5.5-15 %, polypropylene, high density polyethylene (HDPE) and/or 10: (0.5-1.5) mixture or blend of HDPE with polymethyl(metha)acrylates (mol. weight M_n = (55-160) x 10³) , alternating or random copolymer of vinyl monomer (styrene, alkylacrylates or methacrylates, etc.) or α-olefins (C_2-ιo) with anhydrides or esters of unsaturated mono- or dicarbonic acids (mol. weight M_n = (10-200) x 10³) as mattering agent, synthetic silica as an antiblocking agent, erucicamide as a slip agent and allyl phosphite (APH) as antioxidant, calcium stearate as a neutralizer, and tetrakis[methylene (3,5-di-tert-butyl-4-hydroxy-hydro-cinnamate] methane as a stabilizer, (B) > 0.5 μm polypropylene inner layer containing said APH antioxidant, stabilizer, neutralizer and/or slip agent, and/or >1.5 μm inner layer with composition as in (A) matte layer, (C) 10-46 μm virgin or marked polypropylene core layer containing 5-cholesten-3β-ol as a marked agent, said APH antioxidant, stabilizer and neutralizer, and or said slip agent and ethoxylated amine as a antistatic agent, (D) > 1.5 μm polypropylene inner layer containing said APH antioxidant, stabilizer and neutralizer, and (E) > 0.5 μm outer shining layer containing polypropylene, saids antiblocking agent, APH antioxidant and neutralizer, and/or >1.5 μm outer matte layer with composition as a (A) layer.

According to the present invention the technological aspect of manufactured process of said films is distinguished from known processing used in the production of matte 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 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 β-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: (1) Extrusion: extrusion temperature 200-260°C, first chill roll temperature 35-45°C; (2) Longitudinal stretching: stretching roll temperature of first step 150-160°C and second step 140-150°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 170-185°C, temperature of stretching zones 160- 170°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 165-170 °C; Air corona discharge: voltage 15-25 kV and frequency 20-30 kHz. The following Examples of the present invention for preparation of multilayer matte-translucent films with different composition, properties are illustrated.

Example 1

A B/C/D/E structure film with a thickness of 17.5 μm comprising (A) 3.0 μm skin matte-translucent layer from 47.9 % by weight of ethylene(E)-propylene(P)- butylene(B) terpolymer with E-unit content of 3.5 % and B-unit content of 5.5 % (density 0.90 g/cm³, MFI 8.0 g/10 min, m.p. 143.6°C, vicat softening point

120°C, tensile strength 23 MPa, elongation at yield 13 %), 49.9 % by weight of high density polyethylene (HDPE, density 0.964 g/cm³, MFI 3.5 g/10 min, m.p. 134°C, vicat softening point 128°C, Izod impact strength 35 kg-cm/cm, tensile strength 28.4 MPa, elongation at break 500 %) as mattering agent, 1.8 % by weight of polyropylene (density 0.905 g/cm³, MFI 3.5 g/10 min at 230°C and load at 21.6 N, m.p. 163°C, vicat softening point 150°C, Izod impact strength 44 kg- cm/cm, tensile strength 32 MPa, elongation at break 700 %), 0.25% by weight of synthetic silica as an antibocking agent, 0.05 % by weight of erucicamide as a slip agent, 0.05 % by weight of allyl phosphite (APH) as antioxidant, 0.1 % by weight of calcium stearate as a neutralizer, (B) 0.5 μm inner layer from 99.87 % by weight of polypropylene, 0.04 % by weight of allyl phosphite (APH) as a antioxidant, 0.04 % by weight of tetrakis[methylene (3,5-di-tert-butyl-4-hydroxy- hydro-cinnamate] methane as a stabilizer, 0.05 % by weight of calcium stearate as a neutralizer, (C) 13 μm core layer from virgin or marked polypropylene (0.01% of 5-cholesten-3β-ol as a marked agent) with composition as in (B) layer, (D) 0.5 μm polypropylene inner layer with composition as in (B) layer and (E) 0.5 μm outer shining layer from 99,7 % by weight of polypropylene, 0.2 % by weight of said antiblocking agent, 0.05 % by weight of APH antioxidant and 0.05 % by weight of said neutralizer, was prepared by using the tandem extruder system supplied with four satellite co-extruders, flat die, chill roll, recycling line. After biaxially stretching, setting and air corona discharged in the given conditions the film prepared has composition and properties showing in Tables 2, 3 and 4 respectively.

Example 2

The film with a thickness of 50 μm and A/B/C/D E structure as in Example 1 repeated with following changes: (A) matte-translucent skin layer comprises a E- P-B terpolymer with E-unit content of 3.5 % and B-unit content of 5.5 %, thickness of (C) core layer is 45.5 μm; (E) 0.5 μm outer layer is matte containing a E-P-B terpolymer with E-unit content of 4.2 % and B-unit content of 9.0 % and with composition as in (A) layer. After biaxially stretching, setting and air corona discharged in the given conditions the film prepared has composition and properties showing in Tables 2, 3 and 4 respectively.

Example 3

The film with a thickness of 30 μm and A/B/C/D/E structure as in Example 1 repeated with following change: thickness of (C) core layer is 25.5 μm and contains ethoxylated amine as an antistatic agent. After biaxially stretching, setting and air corona discharged in the given conditions 3.0μm / 0.5μm / 25.5μm / 0.5 μm / 0.5μm film prepared has composition and properties showing in Tables 2, 3 and 4 respectively.

Example 4

The film with a thickness of 30 μm and A/B/C/D/E structure as in Example 3 repeated with following changes: (E) shining outer layer comprises a E-P-B terpolymer with E-unit content of 1.5 % and B-unit content of 15 % (MFI 8.0 g/10 min, m.p. 115°C), erucicamide as a slip agent. After biaxially stretching, setting and air corona discharged in the given conditions 3.0μm / 0.5μm / 25.5μm / 0.5μm / 0.5μm film prepared has composition and properties showing in Tables 2, 3 and 4 respectively.

Example 5

The film with a thickness of 30 μm and A/C/D/E structure without (B) inner layer having the composition as in Example 1. After biaxially stretching, setting and air corona discharged in the given conditions 3.0μm / 26μm / 0.5μm / 0.5μm film prepared has composition and properties showing in Tables 2, 3 and 4 respectively.

Example 6

The film with a thickness of 30 μm and A/C/D/E structure without (B) inner layer having the composition as in Example 5 repeated with following changes: (C) core layer contains erucicamide as a slip agent and ethoxylated amine as an antistatic agent. After biaxially stretching, setting and air corona discharged in the given conditions 3μm / 26μm / 0.5μm / 0.5μm film prepared has composition and properties showing in Tables 2, 3 and 4 respectively.

Example 7 The film with a thickness of 30 μm and A/C/D/E structure without (B) inner layer having the composition as in Example 5 repeated with following changes: (E) shining outer layer contains a E-P-B terpolymer with E-unit content of 1.5 % and B-unit content of 15 %, erucicamide as a slip agent. After biaxially stretching, setting and air corona discharged in the given conditions 3μm / 26μm / 0.5μm / 0.5 μm film prepared has composition and properties showing in Tables 2, 3 and 4 respectively. Example 8

The film with a thickness of 15 μm and A/C/E structure having the composition as in Example 1 without (B) and (D) inner layers. After biaxially stretching, setting and air corona discharged in the given conditions 3.0μm / 1 lμm / l.Oμm film prepared has composition and properties showing in Tables 2, 3 and

4 respectively.

Example 9

The film with a thickness of 17.5 μm and A/B/C/D/E structure as in Example 1 repeated with following changes: (A) matte-translucent skin layer comprised a E- P-B terpolymer with E-unit content of 4.2 % and B-unit content of 9.0 %, 10:1 mixture or blend of HDPE with alternating styrene-maleic anhydride copolymer (St-MA, intrinsic viscosity, η_ιn 1.2 dl/g at 20°C in dimethylformamide, molecular weight M_n 2.0 x.10⁵, acid number 550 mg KOH/g, softening point 215°C) as a mattering agent. After biaxially stretching, setting and air corona discharged in the given conditions the film prepared has composition and properties showing in Tables 2, 3 and 4 respectively.

Example 10 The film with a thickness of 17.5 μm and A/B/C/D/E structure as in Example 1 repeated with following changes: (A) matte-translucent skin layer comprised a E- P-B terpolymer with E-unit content of 4.2 % and B-unit content of 9.0 % containing said slip and antiblocking agents (density 0.885 g/cm^'3, MFI 7.3 g/10 min, m.p. 126 °C, vicat softening point 113°C, Izod impact strength 8.7 kg-cm/cm, tensile strength 20 MPa, elongation at break 560 %), 10:1 mixture or blend of HDPE with polymethylmethacrylate (PMMA, density 1.185 g/cm^'3 at 25°C, Tg 376°C by DSC, molecular weight M_n 1.5 x 10⁵, η_ιn 1.52 dl/g at 20°C in acetone) and/or PMMA/polypropylene mixture as a mattering agent. After biaxially stretching, setting and air corona discharged in the given conditions the film prepared has composition and properties showing in Tables 2, 3 and 4 respectively. Example 11

The film with a thickness of 50μm and A/B/C/D/E structure as in Example 9 repeated with following changes: (A) matte-translucent skin layer comprised a E- P-B terpolymer with E-unit content of 3.5 % and B-unit content of 5.5 % and 10:1 mixture or blend of HDPE / α-diisobutylene-maleic anhydride alternating copolymer (softening point 195°C, acid number 665 mg KOH/g, η_m 0.13 dl/g at 20°C in methylethyl ketone). After biaxially stretching in the given conditions, setting and air corona treatment 3.0μm /1.5μm / 43μm / l.Oμm / 1.5μm film prepared has composition and properties showing in Tables 2, 3 and 4 respectively.

For analysis of the initial material used and films prepared following known standard measurement methods are used:

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 \Q°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 are determined in according to ASTM D-882.

Sheen of the film is measured in accordance with ASTM D-2103, the angle of incidence is set at 85°. Haze of the film is mesured in accordance with ASTM D- 1003.

Coefficient of friction of the film is determined in accordance with ASTM D- 1984. Shrinkage of the film is mesured in accordance with ASTM D-1204. The test sample is shrink at 90 and 120°C for a period at 15 min. Longitudinal shrinkage

(LS) and transverse shrinkage (TS) are than given as the difference between the elongation determined (Lt and T_t) compared with the initial lengths (L₀ and T₀) by following equation: LS = (L₀ - L / L_o and TS = (T₀ - T_t) / T₀.

Matte appearance and optical quality of the film are assessed visually ( + good, + + very good and + + + excellent).

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

Table 1. Comparaπve Properties of Present Invention. Known Patents and Commercial Matte Films

[1] - Pat. EP-A-O 479101, [2] - Pat. US 5478643, [3] - Pat. US 5489454, [4] - Pat. US 5492757, [5] - Pat. US 5494717, and [6] - Pat. US 5496600

Measured after storage of corona discharged films for 6 months. Table 2. Compositions of Biaxially Oπented Poiypropvlene Based Matte-Translucent Films of Present Invention

Components C o m p o s i t i o n o f F i l m s ( % ) and Additives El E2 E3 E4 E5 Eb E" E8 E9 E10 Ell

Polypropylene 83 06 93 00 89 86 89 60 90 03 89 88 89 64 80 21 83 07 83 07 93 98

E-P-B terpolvmer (I)* 8 21 2 87 4 78 - 4 80 4 80 4 80 9 60 - - 2 90 E-P-B terpolymer (II)* 0 48 - - - - - - 8 28 8 28 - E-P-B terpolvmer (III)* 5 21 - - 0 40 -

Polyethylene (HDPE) 856 349 500 500 500 500 500 1000 771 7 η\ 270

St- A copolvmer 077

Polymethylmethacrylate 077 DIB-MA copolymer 027

Erucicamide (EA) 001 0005 0005 0006 0005 0005 0006 001 001 001 0003

Synthetic silica (SS) 004 002 002 0024 002 002 0024 005 004 004 002

Calcium stearate (Cast) 005 005 005 005 005 005 005 006 0 0 ^ 005

Tetrakis methane 003 004 005 0055 0035 0035 0035 003 003 003 0036 (TAM)** Allyl phosphite (APH) 004 0045 0065 0055 0055 004 004 004 004 004 004

Ethoxylated amineOEtA) 017 0.17

Terpolymer with following ethylene(E) and butylene(B) unit contents

(I) E-unit content of 3 5 % and B-unit content of 5 5 %

(II) E-unit content of 4 2 % and B-unit content of 9 0 % (rH) E-unit content of 1 5 % and B-unit content of 15 0 %

* Tetrabs [methylene (3,5-di-tert-butyl— l-hydroxy-hydro-cinnamate] methane Table 3 Matte-Translucent Film Layer Compositions of Present Invention

Exp C o m p o s i t i o n o L a y e r s No A B C D E

3 μm 0.5 μm 13 μm 0.5 μm 0.5 μm

E 1 [E(3.5%.-P-B(5.5%) [PP -APH - [PP -APH - [PP - APH - [PP -APH

- PP - HDPE -r SS TAM + Cast] TAM - Cast] TAM - Cast] T SS - Cast]

- EA - APH - Cast]

3 u ϋ.5 μm 45.5 μm 0.5 μm 0.5 μm

E 2 [E(3 5%)-P-B(5 5%) [PP -.APH - [PP -APH - [PP - APH - [E(4 2%.-P-B(9%. - PP - HDPE ⁺ SS TAM - Cast] T.AM -r Cast] T.AM - Cast] - PP * HDPE - SS -r EA -r.APH - Cast] *^• EA- .APH- Cast]

3 μm 0.5 μm 25.5 μm 0.5 μm U.5 μm

E [E(3 5%)-P-B(5 5%) [PP -APH - [PP +APH - [PP - APH - [PP -.APH

- PP - HDPE -r SS TAM -r Cast] - TAM + Cast TAM - Cast] - SS - Cast]

- EA 1- APH - Cast] - EtA]

3 μm 0.5 μm 25.5 μm 0.5 μm 0.5 um

E 4 [E.3 5%)-P-B(5.5%) [PP -APH [PP -APH -rEiA [PP - APH [E(l 5^u/o)-P-B( 15%) - PP - HDPE + SS - TAM -*^• Cast] - T.AM + Cast] T.AM - Cast] - APH T EA - EA - APH - Castl SS - Castl - SS - Castl

3 μm 26 μm 0.5 μm 0.5 μm

E 5 [E.3.5%)-P-B(5.5%) - [PP - -APH - [PP - APH - [PP -APH

- PP - HDPE + SS TAM - Cast] T.AM * Cast] - SS - Cast]

- EA - APH - Castl

3 μm 26 μm 0.5 μm 0.5 um

E 6 [EG 5%)-P-B(5.5%) - [PP -APH - [PP - APH - [PP -APH

- PP - HDPE - SS T.AM - Cast T.AM - Cast] - SS - Cast]

- EA - ΛPH - Castl - EA - EtAI

3 μm 26 μm 0.5 μm 0.5 μm

E 7 [[E(3 5%)-P-B(5.5%) - [PP - APH T [PP - APH [E(1.5%)-P-B(15%) f PP T HDPE + SS TAM + Cast] TAM - Cast] T- APH - EA - -*- EA - APH - Cast] - SS - Cast]

3 μm 13 μm 0.5 μm

E 8 [E(3.5%)-P-B(5.5%) - [PP -APH - - [PP - APH

- PP * HDPE - SS TAM -i- Cast] - SS - Cast]

- EA - APH + Cast]

3 μm 0.5 μm 13 μm 0.5 μm 0.5 μm

E 9 [E(4.2%.-P-B(9%) [PP -APH - [PP -APH - [PP - APH - [PP -APH - - PP - HDPE - St-MA TAM -r Cast] TAM -r Cast] TAM + Cast] SS-r Cast] SS - EA - APH - Cast]

3 μm 0.5 μm 13 μm 0.5 μm 0.5 μm

E 10 [E(4 2%)-P-B(9%) [PP -APH - [PP +APH + [PP -r APH T- [PP -APH -

- PP - HDPE + PMMA TAM + Cast] TAM + Cast] TAM + Cast] SS - Cast]

SS -r EA +APH - Cast]

3 μm 1.5 μm 43 μm 1.0 μm 1.5 μm

E l l [EG.5%)-P-B(5.5%) [PP +APH - [PP -APH - [PP - APH - [PP -APH ~ -PP+HDPE+DIB-MA TAM + Cast] TAM + Cast] TAM -r Cast] SS + Cast] + EA * APH -r Cast] Table 4. Properties of Biaxially Oriented Polypropylene Based Matte-Translucent Films of Present Invention

Properties Example Numbers

E4 E6 E7 ES E9 E10

Ell

Thickness ( μm ) 17.5 50 17.5 17.5 50

Amount of layers

Density ( g/cm^' ) 0.92 0.90 0.90 0.90 0.90 0.91 0.90 0.89 0.92 0.92 0.91

Sheen (angle 85°) Skin matte surface 13 15 15 15 14 13 15 13 10 11 10 Skin shining surface 43 - 61 60 44 42 56 43 60 58 60

Haze ( % ) 55 60 70 70 57 55 62 55 65 70 70 Coefficient of friction 0.5 0.4 0.3 0.5 0.5 0.5 0.6 0.5 0.3 04 0.3

Shrinkage ( % )

90°C in LS 0.5 0.8 1.25 1.2 0.6 0.5 0.5 1.0 0.4 0.5 0.4

90°C in TS 0.25 0.3 0.5 0.5 0.2 0.25 0.4 0.25 0.25 0.2 0.2

120°C in LS 2.5 3.5 5 5.6 2.5 2.2 2.5 3.0 2.5 3.0 3.0

120°C in TS 1.5 2.0 2.25 ι Tj 1.5 1.3 2.0 1.6 1.5 2.0 1.8

Tensile strength ( kg/mm^' ) in LS 22 20 15 18 20 21 12 10 25 23 24 inTS 25 30 30 29 25 26 25 21 61 59 60

Elongation ( % ) in LS 135 145 170 165 140 138 150 135 135 135 135 in TS 55 45 61 61 60 50 52 45 43 45 43

Minimum heat sealing temperature ( °C ) 110 105 105 70 100 105 110 95 105 105 110

Matte appearance (visual assessment)

Surface tension* {mN ι^'m) 40 41 41 40 40 41 41 40 41 41 40

* Measured after storage of corona discharged films for 6 months.

Claims

C l a i m s

1. A five-layer biaxially oriented polypropylene based matte-translucent film with thickness of 15-50 ╬╝m comprise (A) 1.5-3.0 ╬╝m skin matte-translucent layer containing ethylene(E)-propylene(P)-butylene(B) terpolymer with E-unit content of 1.5-4.9 % and B-unit content of 5.5-15 %, polypropylene, high density polyethylene (HDPE) and/or 10: (0.5-1.5) mixture or blend of HDPE with polymethyl(metha)acrylates, alternating or random copolymer of vinyl monomer (styrene, alkyl(metha)acrylates, etc.) or ╬▒-olefins (C_2-10) with anhydrides or esters of unsaturated mono- or dicarbonic acids as mattering agent, synthetic silica as an antiblocking agent, erucicamide as a slip agent and allyl phosphite (APH) as antioxidants, calcium stearate as a neutralizer, and tetrakis [methylene (3,5-di-tert- butyl-4-hydroxy-hydro-cinnamate] methane as a stabilizer, (B) > 0.5 ╬╝m polypropylene inner layer containing said APH antioxidant, stabilizer, neutralizer and/or slip agent, and/or >1.5 ╬╝m inner layer with composition as a (A) matte layer, (C) < 45.5 ╬╝m virgin or marked polypropylene core layer containing 5- cholesten-3╬▓-ol as a marked agent, saids APH antioxidant, stabilizer and neutralizer, and/or said slip agent and ethoxylated amine as a antistatic agent, (D) > 1.5 ╬╝m polypropylene inner layer containing said APH antioxidant, stabilizer and neutralizer, and (E) >0.5 ╬╝m outer shining layer containing polypropylene, said antiblocking agent, APH antioxidant and neutralizer, and/or >1.5 ╬╝m outer matte layer with composition as a (A) layer, were prepared by using the tandem extruder system supplied with three or four satellite co-extruders, flat die, chill roll, and recycling line. Biaxially oriented film (longitudinal stretching at two steps by overall factor of 6-7 times and transverse stretching of 9-10 times) has a sheen of less than or equal to about 15 (angle 85┬░), a longitudinal shrinkage (15 min) of less than or equal to about 1.2 % at 90┬░C and about 5.5 % at 120┬░C, and a transverse shrinkage (15 min) of less than or equal to about 0.5 % at 90┬░C and about 2.2 % at 120┬░C, heat-sealing temperature of or equal to about 70-110┬░C, exellent matte appearance ( + + + visual assessment) and surface tension of equal to about 40-41 mN/m (after storage for 6 months).

2. A film accordind to claim 1 is contained 10.(0.5-1.5) mixture and/or blend of HDPE / alternating styrene-maleic anhydride (St-MA, Exp.9) or ╬▒- diisobutylene-maleic anhydride (DIB-MA, Exp.10) copolymers, or HDPE / polymethylmethacrylate (PMMA, Exp.l l), and other carbonyl containing alternating or random copolymer and/or homopolymer.

3. A film according to claim 1 contains tetrakis [methylene (3,5-di-tert-butyl-4- hydroxy-hydro-cinnamate] methane as a stabilizer and allyl phosphite as an antioxidant.

4. A film according to claim 1, wherein film possessed excellent matte appearance provided with given composition and srtucture of its.

5. A matte-translucent skin layer of the film according to claim 1 have lower value of sheen of less than or equal to about 15 (angle 85┬░).

6. A film according to claim 1 have low value of longitudinal shrinkage (15 min) of less than or equal to about 1.2 % at 90┬░C and about 5.5 % at 120┬░C, and low value of transverse shrinkage (15 min) of less than or equal to about 0.5 % at 90┬░C and about 2.2 % at 120┬░C.

7. A film according to claim 1 have high surface tension value of equal to about 40-41 mN/m after storage for 6 months.

8. A film according to claim 1 have a minimum heat-sealing temperature of equal to about 70-110┬░C.

9. A film according to claim 1 is prepared by using the tandem extruder system supplied with three or four satellite co-extruders, recycling line, flat die and air corona discharge including following stages of production process: (1) extrusion is carried out at 200-280┬░C and taking the co-extruded film off over at first chill roll temperature of 20-40┬░C, (2) longitudinal stretching ratio is from 1.5:1 to 7:1 at 100-160┬░C, (3) transverse stretching ratio is from 7:1 to 10:1 at 160-185┬░C, (4) setting process is produced at 165-170┬░C, and (5) air corona discharge of heat film is carried out at voltage of 15-25 kV and frequency of 20-30 kHz.

10. A film according to claim 9 is prepared by using modified process of chill-roll treatments in two steps of the biaxially orientation allowing to form good homogenized matte film with improved surface properties and dimensional stability.

11. A process of production of film according to claim 9 is included a recycling process of film waste forming in the transverse stretching stage. It is claimed that use of said recycling is decreased film cost by 3.5 %.

12. The films according to claims 1-11 are recommended for photographic paper laminations, reproduction pictures and menu coatings, conventional lamination purposes, hygienic applications, health care products, food stuffs packaging, cosmetics and frames, high speed packaging machines, and as matte tape base films, and for general packaging and overwrapping applications.