JP2007160933A - Matt laminated sealing film of biaxially oriented polyester and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a matt laminated sealing film with excellent transparency of biaxially oriented polyester, which is excellent in sealing performance, imparts ultraviolet ray resistance, is easy to manufacture, is excellent in rolling-up and working properties, and has one matted side. <P>SOLUTION: The matt laminated sealing film of biaxially oriented polyester comprises: a base layer B; a sealing outer layer A: and another matt outer layer C located on opposite side of the outer layer A based on the base layer B, wherein: (a) the sealing outer layer A contains not more than 0.01 wt.% of particles based on the weight of the sealing outer layer A; and (b) the matt outer layer C comprises a copolymerized polyester containing 6-30 mol% of isophthalic acid unit, and contains 1.0-7.0 wt.% of particles, based on the weight of the matt outer layer C, whose mean particle size d<SB>50</SB>is 2-10 μm and particle size distribution in terms of SPAN98 method is 1.2-2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sealable matte biaxially stretched laminated polyester film. More specifically, the present invention is excellent in sealability and can be suitably used for outdoor articles such as greenhouses and roofs. The present invention relates to a sealing matte biaxially stretched laminated polyester film that can be suitably used as a protective film for a metal surface and has an attractive appearance because it has a matte property (particularly when used on a metal surface). The present invention further relates to a method for producing the film and its use.

  Biaxially stretched polyester films having a sealing property on one side and matting on the other side are well known. For example, a sealable coextruded laminated polyester film having a sealable outer layer on one side and a matte layer on the other side is known (for example, see Patent Document 1). The sealing outer layer of this film contains isophthalic acid units and terephthalic acid units, and its surface shape is also defined. The matte outer layer on the opposite side contains inert particles at a high concentration (preferably 1 to 18% by weight) and is composed of polyethylene terephthalate and a copolyester. And the said copolyester contains each unit of isophthalic acid, aliphatic dicarboxylic acid, and a sulfo monomer. This film is excellent in transparency but is expensive to manufacture. That is, in order to contain a high concentration of inert particles in polyethylene terephthalate or a mixture thereof, it becomes like a polymer cross-linked at a high concentration, and requires a large stretching force compared to a polymer not containing inert particles. To do. Accordingly, the number of breaks of the film increases in the film manufacturing process. In addition, as a comparison of this type of film, when the sealing outer layer is a film containing no particles, the handleability and processability of the film are poor, which is not practical.

Further, a single-side matte coextrusion laminated polyester film comprising at least one base layer B and at least one matte outer layer A is known (for example, see Patent Document 2). The matte overlayer A containing particles are 2~10μm average particle size _{d 50} in the particle size distribution defined by SPAN98 of 2.0 or less. The polyester constituting the matte outer layer A has 4 to 30 mol% of isophthalic acid units based on digalbonic acid units in the polyester, and the content of the particles is 1.0 to 7.0% by weight. is there. Although this type of film is easy to manufacture, the sealing properties are insufficient.

  In addition, when the film does not contain an ultraviolet resistant compound such as an ultraviolet absorber, when used outdoors, photo-oxidative decomposition due to sunlight occurs in a short period of time, and the film may turn yellow or mechanical properties may deteriorate. . Therefore, research has been conducted on UV-resistant sealing biaxially stretched polyester films.

  For example, a sealable biaxially stretched polyester film having a UV resistance and comprising three layers of a base layer B, a sealable outer layer A, and a non-sealable outer layer C is known (for example, see Patent Document 1). The minimum sealing temperature of the sealable outer layer A of this type of film is usually around 110 ° C., and the seal seam strength is 1.3 N / 15 mm (film width 15 mm) or more. Further, in this type of film, the surface shapes of the outer layers A and C are defined, and an effective amount of an ultraviolet absorber is contained. Although the particles are not contained in the sealing outer layer A compared with this type of film, in this case, the handleability and processing characteristics of the film are inferior, and there is no example in which matteness is imparted to one side.

  A sealable coextruded laminated polyester film comprising one or more base layers, a sealable outer layer, and a non-sealable outer layer is also known (see, for example, Patent Document 2). The sealing outer layer is made of a copolyester containing isophthalic acid units and terephthalic acid units. The base layer further contains 0.1 to 10% by weight of an ultraviolet absorber and contains a known anti-blocking agent. Although this type of film has good sealing properties, it has poor processing characteristics and also has disadvantages in optical properties. This type of film has a matte property, but has a high haze of less than 75% and poor transparency.

  Furthermore, a biaxially stretched polyester film having a sealing property on one side and matting on the other side and containing an ultraviolet absorber is also known (for example, see Patent Document 3). The sealing outer layer of this film contains isophthalic acid units and terephthalic acid units, and its surface shape is also defined. The matte outer layer on the opposite side contains inert particles at a high concentration (preferably 1 to 18% by weight) and is composed of polyethylene terephthalate and a copolyester. And the said copolyester contains each unit of isophthalic acid, aliphatic dicarboxylic acid, and a sulfo monomer. This film is excellent in transparency but is expensive to manufacture. That is, in order to contain a high concentration of inert particles in polyethylene terephthalate or a mixture thereof, it becomes like a polymer cross-linked at a high concentration, and requires a large stretching force compared to a polymer not containing inert particles. To do. Accordingly, the number of breaks of the film increases in the film manufacturing process. Moreover, since this film contains the ultraviolet stabilizer only in the two outer layers, the ultraviolet resistance is insufficient. In addition, as a comparison of this type of film, when the sealing outer layer is a film containing no particles, the handleability and processability of the film are poor, which is not practical.

European Patent Application No. 1219413 European Patent Application No. 1442875 European Patent Application No. 1125732 European Patent No. 09203181 European Patent Application No. 1274579

  Accordingly, an object of the present invention is to provide a biaxial shaft that has a sealing property on one side, a matte surface on the other side, and preferably has UV resistance, and solves the problems of the prior art as described above. It is to provide a stretched polyester film. In particular, the biaxially stretched polyester film is not only (1) improved in sealing properties between sealing surfaces, but also APET (amorphous polyethylene terephthalate), CPET (crystalline polyethylene terephthalate), A / CPET (APET is the inner surface) Having a good sealing property with the two-layer laminate (for example, food tray) in which CPET constitutes the outer surface, metal surface, etc., (2) having ultraviolet resistance, and (3) manufacturing (particularly stretchability) ) Is easy, (4) excellent in winding properties and processing properties, and (5) improved optical properties (especially haze and matte properties).

  Specifically, the excellent sealing property means that the minimum sealing temperature in the fin sealing of the sealing outer layer A (sealing between the sealing outer layers A) is preferably less than 110 ° C., more preferably less than 108 ° C., and particularly preferably Although it was less than 106 ° C. and measured by seal seam strength (seal temperature: 130 ° C.), it is preferably 1.5 N / 15 mm or more, more preferably 1.6 N / 15 mm or more, and particularly preferably 1.7 N / 15 mm or more. The minimum sealing temperature in the seal between the sealing outer layer A and APET (amorphous polyethylene terephthalate) is preferably 140 ° C. or lower, more preferably 139 ° C. or lower, particularly preferably 138 ° C. or lower. (Sealing temperature: 140 ° C.) is preferably 1.5 N / 15 mm or more, more preferably 1.6 N / 15 m or more, particularly preferably means that at 1.7 N / 15 mm or more. Furthermore, it has excellent sealing properties for substrates such as metals (aluminum, steel, coated steel, chrome-plated steel, galvanized steel (tin), tinplate).

  One example of excellent winding characteristics and processing characteristics is that it can be applied to high-speed machines. In addition, recycled materials (for example, film scraps generated in the production process) can be blended in the extrusion process at a ratio of usually 60% by weight or less with respect to the weight of the film, whereby the physical properties (physical properties of the film of the present invention It is preferable that the optical characteristics, optical characteristics, etc. are not adversely affected.

  In addition, when the film is used at the boundary between outdoor and / or indoor, excellent ultraviolet resistance is required. Excellent UV resistance means that the film is hardly or substantially not deteriorated by sunlight irradiation or UV irradiation. In particular, when used as an outdoor article for several years, it is preferable that coloring, yellowing, embrittlement, surface cracking, deterioration of mechanical properties, and the like do not occur. Further, the excellent ultraviolet resistance means that the film absorbs ultraviolet rays and does not transmit light in the ultraviolet region up to the visible light region.

  In order to solve the above-mentioned problems, the present inventors have intensively studied. As a result, the sealing matte biaxial stretching comprising the base layer B, the sealing outer layer A having a specific configuration, and the matting outer layer C having a specific configuration. The present inventors have found that the above object can be achieved by a laminated polyester film, and have completed the present invention.

That is, the first gist of the present invention comprises at least one base layer B, a sealing outer layer A, and another matting outer layer C located on the opposite side of the outer layer A with respect to the base layer B. A sealable matte biaxially stretched laminated polyester film, wherein a) the sealable outer layer A contains particles in an amount of 0.01% by weight or less based on the weight of the sealable outer layer A, and b) the matteness. The outer layer C is made of a copolyester containing 6 to 30 mol% of isophthalic acid units, and has an average particle size d ₅₀ of 2 to 10 μm and a particle size distribution represented by the SPAN 98 method of 1.2 to 2. The present invention resides in a sealable matte biaxially stretched laminated polyester film characterized by containing 1.0 to 7.0% by weight of certain particles based on the weight of the matte outer layer C.

  The second gist of the present invention is a method for producing the sealing matte biaxially stretched laminated polyester film described in the first gist, and the production method comprises a coherent extrusion method for sealing outer layer A and base layer B. And a step of obtaining a laminated sheet comprising the matte outer layer C, a step of biaxially stretching the obtained laminated sheet to obtain a biaxially stretched film, and a step of thermally fixing the obtained biaxially stretched film It exists in the manufacturing method of the sealing property mat | matte biaxially stretched laminated polyester film characterized by the above-mentioned.

  The sealable matte biaxially stretched laminated polyester film of the present invention is excellent in sealability (not only for seal layers but also for APET, CPET, A / CPET, metal substrate, etc.) and imparts UV resistance. It is a film that is easy to manufacture, excellent in winding and processing characteristics, and is excellent in transparency with a matte surface on one side, and can be used not only indoors but also in various outdoor applications.

  Hereinafter, the present invention will be described in detail. The film of the present invention comprises at least three layers: a base layer B, a sealing outer layer A, and a matte (non-sealing) outer layer C. Preferably it contains a UV stabilizer.

Base layer B:
The base layer B is composed of 90% by weight or more of thermoplastic polyester. As the thermoplastic polyester constituting the base layer B, polyethylene terephthalate (PET) produced from ethylene glycol and terephthalic acid, polyethylene-2,6-naphthalate produced from ethylene glycol and naphthalene-2,6-dicarboxylic acid ( PEN), poly (1,4-cyclohexanedimethylene terephthalate) (PCDT) produced from 1,4-bishydroxymethylcyclohexane and terephthalic acid, ethylene glycol, naphthalene-2,6-dicarboxylic acid and biphenyl-4,4 Poly (ethylene 2,6-naphthalate bibenzoate) (PENBB) made from '-dicarboxylic acid is preferred. Particularly preferred is a polyester comprising 90% or more, preferably 95% or more of a unit comprising ethylene glycol and terephthalic acid or a unit comprising ethylene glycol and naphthalene-2,6-dicarboxylic acid.

  The remaining monomer units other than the above monomers are monomers derived from other diols and / or dicarboxylic acids.

Examples of the copolymer diol include diethylene glycol, triethylene glycol, and aliphatic glycol represented by the formula of HO— (CH ₂ ) _n —OH (n represents an integer of 3 to 6, specifically 1,3-propane. Diol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol), branched aliphatic glycols having up to 6 carbon atoms, HO—C ₆ H ₄ —X—C ₆ H Aromatic diol represented by _4- OH (wherein X represents —CH ₂ —, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, —O—, —S—, —SO ₂ —). represented), _wherein: bisphenol is preferably represented by _{HO-C 6 H 4 -C 6} H 4 -OH.

  As the copolymerized dicarboxylic acid, aromatic dicarboxylic acid, alicyclic dicarboxylic acid, and aliphatic dicarboxylic acid are preferable.

  Preferred examples of the aliphatic dicarboxylic acid include benzenedicarboxylic acid, naphthalene dicarboxylic acid such as naphthalene-1,4- or -1,6-dicarboxylic acid, and biphenyl-x, x such as biphenyl-4,4′-dicarboxylic acid. Examples include diphenylacetylene-x, x-dicarboxylic acid such as' -dicarboxylic acid and diphenylacetylene-4,4'-dicarboxylic acid, and stilbene-x, x-dicarboxylic acid.

Preferable examples of the alicyclic dicarboxylic acid include cyclohexanedicarboxylic acid such as cyclohexane-1,4-dicarboxylic acid. Among the aliphatic dicarboxylic acids, include alkane dicarboxylic acids C ₃ -C _19, the alkane may be branched may be linear.

  Said polyester is manufactured by transesterification. The starting materials are known transesterification catalysts such as dicarboxylic acid esters, diols, zinc salts, calcium salts, lithium salts, magnesium, and manganese salts. The produced intermediate is further subjected to polycondensation in the presence of a polycondensation catalyst such as antimony trioxide and a titanium salt. In addition, the polyester may be produced by a direct or continuous esterification reaction in the presence of a polycondensation catalyst in the starting dicarboxylic acid and diol. A commercial item can also be used for said polyester.

  You may add well-known additives, such as a stabilizer and particle | grains (an antiblocking agent, a filler, etc.), to the base layer B of the film of this invention. Examples of the stabilizer include a phosphoric acid compound and a phosphoric acid ester.

  Examples of the above particles (anti-blocking agent, filler, etc.) include inorganic and / or organic particles. Specifically, calcium carbonate, amorphous silica, talc, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate. Examples thereof include lithium phosphate, calcium phosphate, magnesium phosphate, alumina, LiF, calcium dicarboxylate, barium, zinc or manganese salt, carbon black, titanium dioxide, kaolin, crosslinked polystyrene particles, and crosslinked acrylate particles.

  In addition, from the viewpoint of achieving a low haze of the film, the base layer B preferably contains substantially no particles or contains only particles derived from the recycled raw material even if contained.

Sealing outer layer A:
The sealable outer layer A is laminated on the base layer B by a coextrusion method. The outer layer A is made of a copolyester having units derived from isophthalic acid, terephthalic acid and ethylene glycol. The remaining monomer units other than the above monomers are the aliphatic, alicyclic, aromatic diols and dicarboxylic acids described in the section of the base layer B. Copolyesters that give good sealing properties consist of ethylene terephthalate units and ethylene isophthalate units. The proportion of each unit is usually 60-95 mol% ethylene terephthalate units and 40-5 mol% ethylene isophthalate units, preferably 65-90 mol% ethylene terephthalate units and 35-10 mol% ethylene isophthalate units. Particularly preferred are 70 to 85 mol% ethylene terephthalate units and 30 to 15 mol% ethylene isophthalate units.

  The sealable outer layer A preferably contains 0.01% by weight or less of particles, and more preferably contains substantially no particles. Thereby, in particular, in the sealable outer layer A composed of the above-described constituent components, good sealability can be imparted. That is, since no particles are present, no bubbles are present near the surface of the sealable outer layer A, and sealing can be performed over the entire surface of the sealable outer layer A. In other words, when particles are present, voids are formed due to the presence of the corners of the particles, resulting in an incomplete seal when the films are laminated and sealed, and optical defects also occur. In the case where particles are contained in the sealing outer layer A, those described for the base layer B can be adopted as specific examples of the particles.

  The sealing properties of the sealing outer layer A are determined by the chemical composition of the copolyester, the thickness of the sealing outer layer A, the surface shape, and the like.

  The minimum sealing temperature in the fin sealing of the sealing outer layer A (sealing between the sealing outer layers A) is preferably 110 ° C. or lower, more preferably 108 ° C. or lower, particularly preferably 106 ° C. or lower. (Temperature: 130 ° C.) is preferably 1.5 N / 15 mm or more, more preferably 1.6 N / 15 mm or more, and particularly preferably 1.7 N / 15 mm or more. The minimum sealing temperature in the seal between the sealing outer layer A and APET (amorphous polyethylene terephthalate) is preferably 140 ° C. or lower, more preferably 139 ° C. or lower, particularly preferably 138 ° C. or lower. (Temperature: 140 ° C.) is preferably 1.5 N / 15 mm or more, more preferably 1.6 N / 15 mm or more, and particularly preferably 1.7 N / 15 mm or more. Usually, it is possible to improve the sealing properties when the copolymer polyester constituting the sealing outer layer A does not contain inorganic or organic particles. In this case, the lowest lowest seal temperature and the highest seal seam strength can be achieved under the given conditions of copolymer polyester and sealable outer layer A thickness. In addition, blocking of the sealing outer layer A can be prevented by containing a very small amount of particles. As the particles, the anti-blocking agent particles described in the base layer B can be used.

Matte outer layer C:
In the present invention, the matte outer layer C has the following characteristics. That is, the matte outer layer C is made of polyester containing 6 to 30 mol% of isophthalic acid units, and has an average particle size d ₅₀ of 2 to 10 μm and a particle size distribution represented by the SPAN 98 method of 1.2. The particles which are ˜2 are contained in an amount of 1.0 to 7.0% by weight based on the weight of the matte outer layer C.

  The matte outer layer C is preferably composed of a polyester containing 6 to 30 mol%, more preferably 8 to 28, particularly preferably 10 to 26 mol% of isophthalic acid units. The structural unit other than the isophthalic acid unit is a unit composed of the aliphatic, alicyclic, aromatic diol and dicarboxylic acid described in the section of the base layer B. Particularly preferred is a polyester comprising an isophthalic acid unit within the above range and a polyester used in the base layer B. Here, having an isophthalic acid unit in the above range means that the isophthalic acid unit is in the above range even if it is a copolyester of the isophthalic acid unit in the above range and the polyester used in the base layer B. A mixture of a polyester having an isophthalic acid unit and a polyester used in the base layer B may be used. Therefore, as a preparation method, even if a copolyester having an isophthalic acid unit in the above range is used directly, various polyesters are mixed using a master batch, and the isophthalic acid unit is adjusted to be in the above range. May be.

  A preferred polyester constituting the matte outer layer C is a copolymerized polyester composed of terephthalic acid units, isophthalic acid units and ethylene glycol units, and the composition ratio is such that the terephthalic acid units are 70 to 94 as the dicarboxylic acid component. Mol%, preferably 74 to 92 mol%, more preferably 76 to 90 mol%, and isophthalic acid units 28 to 6 mol%, preferably 26 to 8 mol%, more preferably 24 to 10 mol%. Is preferred.

  When the polyester constituting the matte outer layer C has a remaining portion, it is preferably composed of structural units of the polyester constituting the base layer B.

  By using the raw material polyester as described above as the polyester constituting the matte outer layer C, the haze of the obtained film can be significantly reduced, and the film can be produced stably. Compared with a known film of the same type that contains the same amount of particles in the matte outer layer C as in the present invention, the number of film breaks in the film production process can be greatly reduced. As is clear from FIG. 1, the stretching stress can be significantly reduced by appropriately selecting the content of the isophthalic acid unit.

By making the matte outer layer C contain the above particles within the above range, desired matteness can be achieved. The average particle diameter d ₅₀ of the particles contained in the matte outer layer C is 2 to 10 μm, preferably 2.2 to 9 μm, more preferably 2.4 to 8 μm, and particularly preferably 2.6 to 7 μm. If the average particle size d ₅₀ of the particles 2μm smaller, haze increases as compared to the particle concentration. When the average particle diameter d _{50 of the} particles exceeds 10 μm, a problem occurs in the filter for removing foreign substances.

  The particle size distribution represented by the SPAN 98 method of the particles contained in the matte outer layer C is 1.2 or more, 2 or less, preferably 1.9 or less, more preferably 1.8 or less. When the particle size distribution expressed by the SPAN 98 method exceeds 2.0, the gloss of the matte outer layer C becomes large, and the matteness cannot be achieved. When the particle size distribution represented by the SPAN98 method of the particles is less than 1.2, the rollability of the film is deteriorated and the film is likely to be blocked.

  The content of the particles contained in the matte outer layer C is 1.0 to 7.0% by weight, preferably 2.0 to 6.5% by weight, more preferably 3 based on the weight of the matte outer layer C. 0.0 to 6.0% by weight. When the content of the particles to be contained in the matte outer layer C is less than 10% by weight, the matteness is not sufficient, and when it exceeds 7.0% by weight, the haze becomes high.

  Examples of the above-mentioned particles that impart a preferable matting property to the matte outer layer C include inorganic and / or organic particles. Specifically, calcium carbonate, amorphous silica, talc, magnesium carbonate, barium carbonate, sulfuric acid Calcium, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, aluminum oxide, lithium fluoride, dicarboxylic acid calcium, barium, zinc or manganese salt, carbon black, titanium dioxide, kaolin, crosslinked polystyrene particles, crosslinked acrylate particles, etc. Is exemplified.

In addition to the above particles, other particles may be added to the matte outer layer C. However, other additives particles to particles to impart matte sex defined above, it is preferable that the average particle size d ₅₀ less. When the average particle size d ₅₀ of the particles imparting the matte property defined above and / or the particle size distribution represented by the SPAN 98 method is not within the above specified range, and there are particles within the above specified range. If not, the above-mentioned problems occur.

  Synthetic silica particles (colloidal) are preferable as the above-mentioned particles imparting matte properties. Colloidal amorphous silica particles are advantageous in that they are well dispersed in the polymer matrix and bubbles are hardly formed. Bubbles are usually generated during biaxial stretching and are not preferable in the present invention because haze is increased.

Synthetic silica particles (including silica gel) are usually obtained in the form of a hydrosol by mixing sulfuric acid and sodium silicate while controlling the reaction conditions. The end result is a hard, transparent and massive hydrogel. The double product sodium sulfate is removed by washing with water, dried and then processed. Important physical property values of the obtained silica gel are pore volume, pore diameter, and surface area, which are prepared by pH in water washing and drying conditions. In order to obtain synthetic silica particles having an average particle size d ₅₀ defined by the present invention and a particle size distribution represented by the SPAN 98 method, it is preferable to prepare the silica gel by mechanically or hydrodynamically pulverizing it. Synthetic silica particles can be obtained from Grace (USA), Fuji (Japan), Degussa (Germany), and Ineos (UK).

  In the present invention, the surface roughness Ra of the matte outer layer C is preferably 150 nm or more and 1000 nm, more preferably 175 nm or more and 950 nm, and particularly preferably 200 nm or more and 900 nm. When the surface roughness Ra of the matte outer layer C is less than 150 nm, the matte property may not be sufficient, and when it exceeds 1000 nm, the optical properties of the film may be deteriorated.

  The coefficient of friction (C-side surface / C-side surface) of the matte outer layer C is preferably less than 0.45, more preferably less than 0.40, and particularly preferably less than 0.35.

UV stabilizer:
The laminated polyester film of the present invention preferably contains an ultraviolet stabilizer. The UV stabilizer can be selected from organic or inorganic UV stabilizers to be added to the polyester. Details of preferred UV stabilizers are disclosed in International Patent Application WO 98/06575, European Patent 0006686, European Patent 0031202, European Patent 0031203, and European Patent 0076582. It is described in.

  The ultraviolet light stabilizer used in the present invention is a light stabilizer and is usually a chemical compound, and suppresses physical or chemical photolysis processes by absorbing ultraviolet light. Carbon black, titanium oxide, zinc oxide (see, for example, EP 1368405) and other pigments have some light protection effects. However, since these are pigments, the color of the film changes and cannot be used for transparent films. Therefore, it is preferable that the ultraviolet stabilizer used in the transparent film is an organic compound or an organometallic compound, and hardly changes in color due to the addition, and is a stable compound that is soluble in the thermoplastic resin.

  The ultraviolet stabilizer used for the above purpose preferably absorbs ultraviolet rays having a wavelength of 180 to 380 nm, more preferably 280 to 360 nm, preferably 70% or more, more preferably 80% or more, particularly preferably 90% or more. It is preferable that it is a compound to be. Furthermore, it is preferably a compound that is thermally stable in a temperature range of 260 to 300 ° C., does not decompose, and does not generate gas.

  Specific examples of UV stabilizers include 2-hydroxybenzophenone, 2-hydroxybenzotriazoles, organonickel compounds, salicyl esters, cinnam ester derivatives, resorcinol monobenzoates, oxanilides, hydroxybenzoate esters, hindered amines. And triazines, among which 2-hydroxybenzotriazoles and triazines are preferred.

  The content of the UV stabilizer is usually 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 1.5 to 2%, based on the weight of the polyester in each layer to be blended. .5% by weight.

  In a preferred embodiment, as the UV stabilizer, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-hexyloxyphenol or 2,2′-methylenebis (6- (2H Benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol) is preferably contained in an amount of 0.01 to 5.0% by weight based on the weight of the polyester in each layer. . The above ultraviolet stabilizers may be used in combination of two or more, and the total content of the ultraviolet stabilizers in that case is preferably 0.01 to 5.0, based on the weight of the thermoplastic polyester in each layer. % By weight.

  The UV stabilizer is preferably blended in at least the base layer B and the (non-sealable) matte outer layer C. If necessary, you may mix | blend with the sealing outer layer A. The content of the UV stabilizer is based on the layer in which it is contained.

  In the case of the above three-layer film, it is known in a weather resistance test measured according to ISO 4892 using Atlas Ci 65 Weather-Ometer by adding a UV stabilizer to the base layer B and the matte outer layer C. As compared with the above film, a sufficient UV resistance improving effect is observed.

  In the same weather resistance test as the film of the present invention exposed to the outdoors for 5 to 7 years, yellowing is not observed, the film does not become brittle, the surface gloss value does not decrease, No cracks occur and no deterioration of mechanical properties is observed. The UV stabilizer is added to an extruder during the production of the thermoplastic polymer or the film.

  The UV stabilizer is particularly preferably added by a master batch method. First, a UV stabilizer is dispersed in a solid carrier. As the carrier material, a thermoplastic resin itself such as polyethylene terephthalate may be used, or another polymer having sufficient compatibility with these may be used. After the UV stabilizer is added to the thermoplastic resin for film production, the components of the masterbatch are melted during extrusion, and the UV stabilizer is dissolved in the thermoplastic resin.

  The content of the UV stabilizer in the master batch containing the UV stabilizer is 2.0 to 50.0 wt%, preferably 5.0 to 30.0 wt%, with the total weight of the master batch being 100 wt%. is there.

  In the master batch method, it is preferable that the particle size and bulk density of the particles in the master batch are the same as the particle size and bulk density of the thermoplastic resin particles. Thereby, uniform dispersion of the ultraviolet stabilizer is achieved, and uniform ultraviolet resistance can be achieved.

  The gloss (incident light 60 °) on the matte outer layer C side of the laminated film of the present invention is preferably less than 70, more preferably less than 60, and particularly preferably less than 50. Such a film surface is extremely excellent as a film used for advertising purposes, and is particularly effective when laminated on a steel plate so as to form an outer surface.

  The haze of the laminated film of the present invention is preferably less than 45%, more preferably less than 40%, and particularly preferably less than 30%. The transparency of the laminated film of the present invention is preferably greater than 80%, more preferably greater than 84%, and particularly preferably greater than 88%. The film of the present invention has low haze and high transparency as compared with known single-layer matte films as shown in Comparative Examples described later. Therefore, printing that can be recognized very easily by reverse printing can be performed.

  The thickness of the sealing outer layer A usually exceeds 0.4 μm, preferably 0.5 to 10.0 μm, more preferably 0.8 to 9.0 μm, and still more preferably 1.0 to 8.0 μm.

  The thickness of the matte outer layer C is usually more than 0.4 μm, preferably 0.5 to 10.0 μm, more preferably 0.8 to 9.0 μm, still more preferably 1.0 to 8.0 μm. . The thicknesses of the outer layers A and C may be the same or different.

  The thickness of the polyester film of the present invention can take a wide range, and is usually 5 to 100 μm, preferably 6 to 90 μm, more preferably 7 to 80 μm. It is preferable that the thickness of the base layer B occupies 5 to 90% of the total thickness of the film.

  The film of the present invention exhibits excellent UV resistance by adding an UV stabilizer, and the surface of the matte outer layer C side has low gloss and high transparency despite the low haze. Furthermore, it has excellent winding characteristics and processing characteristics.

Film production method:
Subsequently, the manufacturing method of the film of this invention is demonstrated. The film of the present invention can be produced by a known coextrusion method. A step of obtaining a laminated sheet comprising a sealing outer layer A, a base layer B and a matte outer layer C by a coextrusion method, and biaxially stretching the obtained laminated sheet Thus, a biaxially stretched film is obtained, and the obtained biaxially stretched film is heat-set. Specifically, the raw material polymers for the base layer B, the sealing outer layer A, and the outer layer C are supplied to separate extruders, and each layer is coextruded through a flat film die to obtain a molten sheet, and a cooling roll And if necessary, take the molten sheet using another roll, solidify to obtain a laminated sheet, biaxially stretch the obtained laminated sheet in the longitudinal direction and the transverse direction to obtain a biaxially stretched film, It consists of each process of heat-setting the obtained biaxially stretched film. If necessary, the surface of the film may be subjected to corona treatment or flame treatment.

  Specifically, first, the molten polymer or polymer mixture of each layer is supplied to the extruder of each layer, compression-plasticization is performed, and if necessary, each additive is added and mixed with the polymer at this stage. . Each molten polymer is simultaneously coextruded through a flat-film die, the extruded laminate is taken up using one or more cooling rolls and take-up rolls, cooled and solidified to obtain a laminated amorphous sheet.

  Usually, biaxial stretching is performed continuously. In this case, it is preferable to first stretch in the longitudinal direction (machine direction) and then stretch in the transverse direction (perpendicular to the machine direction). Thereby, the molecular chain is oriented. Usually, the stretching in the longitudinal direction is performed using two or more rolls having different rotational speeds corresponding to the stretching ratio, and the stretching in the transverse direction uses a tenter frame, sandwiching the end of the film and higher. This is done by applying stress at temperature.

  The temperature during stretching is determined by the desired physical properties of the film and can be selected within a wide range. Usually, the stretching in the longitudinal direction is performed at a temperature of 80 to 130 ° C, and the stretching in the transverse direction is performed at a temperature of 90 to 150 ° C. The stretch ratio in the longitudinal direction is usually 2.5: 1 to 6.0: 1, preferably 3.0: 1 to 5.5: 1. The stretching ratio in the transverse direction is usually 3.0: 1 to 5.0: 1, preferably 3.5: 1 to 4.5: 1.

  The film is then heat set. The heat setting is performed at a temperature of 150 to 250 ° C. for 0.1 to 10 seconds. The film is wound up by a known method.

  The matte (non-seal) outer layer C side surface of the heat-set biaxially stretched polyester film may be subjected to corona treatment or flame treatment. These treatments are performed so that the surface tension of the film usually has a strength exceeding 50 mN / m.

  In order to impart other desired physical properties to the film, a coating layer may be formed on the film surface. Typical coating layers include an adhesion promoting layer, an antistatic layer, a slippery layer, a release layer, and the like. Such a coating layer is preferably formed by in-line coating using a water dispersant before transverse stretching.

  The film of the present invention has sealing properties on one side, matting properties on the other side, excellent sealing properties, and exhibits excellent UV resistance and weather resistance by adding a UV stabilizer, It has many advantages such as easy manufacture, excellent processing characteristics, and excellent optical characteristics. The sealable outer layer A is not only excellent in sealability with the sealable outer layer A itself, but also excellent in sealability with the matte outer layer C, and further, APET (amorphous polyethylene terephthalate), A / CPE (crystalline polyethylene terephthalate), CPET, metal (aluminum, steel, coated steel, chrome-plated steel, zinc-plated steel (tin), tinplate) and other excellent sealing properties. Therefore, the film of the present invention can be used for various sectors (partition plates).

  Since the film of the present invention has various characteristics as described above, it can be applied to various fields. For example, interior covering materials, display stand materials, display necessities, displays, placards, protective covers for machines and automobiles, light dividers, store necessities, advertising supplies, laminated materials used in the above materials, etc. It can be suitably applied.

  When UV resistance is imparted to the film of the present invention, application to fields used outdoors is also possible. For example, it can be suitably applied to greenhouses, advertising tower members, roofs, covering materials for articles used outdoors, cover for articles, protective materials for metal surfaces such as iron plates, partition materials for construction, advertising lighting members, and the like.

  The film of the present invention is a film having a non-reflective (non-glossy) matte layer C side surface and high transparency. Furthermore, in the film of the present invention, recycled raw materials (for example, film scraps generated in the production process) can be blended in the extrusion process at a ratio of usually 60% by weight or less with respect to the weight of the film. The addition of the regenerated raw material does not adversely affect the physical properties of the film of the present invention.

  Furthermore, the film of the present invention can be particularly suitably used for a flexible packaging film that sufficiently exhibits its excellent properties, particularly excellent sealing properties and processability. In particular, it can be used suitably for a high-speed packaging machine.

  The characteristics of the film of the present invention are summarized in Table 1 below.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded. The measurement methods used in the following examples are described below.

(1) Average particle diameter d ₅₀ :
The average particle size _{d 50} is Malvern Master Sizer (Malvern Instruments Ltd., UK) was measured by a general method by a laser on a (Horiba LA 500 (manufactured by HORIBA, Ltd.) or Helos (Sympathec GmbH Co., Germany) device But it is basically the same measurement). Place the sample in a cell containing water and set it in the test apparatus. The test is performed automatically and a mathematical calculation of the particle size d ₅₀ is also performed.

The value of d ₅₀ value is determined from the cumulative particle size distribution curve. FIG. 2 shows the cumulative particle size distribution curve. It was determined values of _{d 50} in 50%.

(2) Measurement of SPAN98:
SPAN 98 showing the particle size distribution was measured using the apparatus used in the measurement of the average particle size d ₅₀ described above. SPAN98 is represented by the following formula.

_{SPAN98 = (d 98 -d 10)} / d 50

d ₉₈ and d ₁₀ are the particle sizes at 98% and 10% of the cumulative particle size distribution curve shown in FIG. 3, respectively. Figure 3 shows the relevant part of the _{d 98} and _{d 10.}

(3) Seal seam strength against APET:
Measurement was performed by the method shown in FIG. A film of 100 mm (length) x 15 mm (width) and the APET side of a ready-made food tray were overlaid and sealed at a seal temperature of 140 ° C., a seal time of 0.5 seconds, and a seal pressure of 3 bar (use apparatus: HSG / ET (Brugger, Germany, sealing jaws performed each other.) Next, as shown in FIG. 4, the unsealed end of the film (1) and the end of the APET / CPET tray (2) were stress measured. Fixed to a jig (3) of a vessel (for example, C-FR1.0TH.D09 Universal test machine, manufactured by Zwick, Germany), 180 ° with respect to the seal part at a speed of 200 mm / min in the direction of the arrow at 23 ° C. The stress when the seal part peels is measured by applying a stress in the direction.The seal seam strength is expressed as stress (N) / film width (15 mm). ).

(4) Determination of minimum seal temperature for APET:
A heat-sealed sample (seal seam = 15 mm × 100 mm) was prepared using a Brugger HSG / ET sealing device. Sealing was carried out at different temperatures using two heated seal sandwiches with a seal pressure of 3 bar and a seal time of 0.5 seconds. Stress is applied to the seal portion in the direction of 180 ° using the stress measuring instrument described above, and the stress when the seal portion peels is measured. The temperature when the seal seam strength reached 0.5 N / 15 mm was defined as the minimum seal temperature.

(5) Seal seam strength between the sealable outer layers A (fin sealing):
Two films of 100 mm (length) × 15 mm (width) were overlapped and sealed at a sealing temperature of 130 ° C., a sealing time of 0.5 seconds, and a sealing pressure of 2 bar (use apparatus: HSG / ET (Brugger, Germany, The seal seam strength was measured by a T-type peel test at a rate of 200 mm / min (2.90 °) at 23 ° C.

(6) Determination of minimum seal temperature for APET:
A heat-sealed sample (sealed seam = 20 mm × 100 mm) was prepared using a Brugger HSG / ET sealing device. Sealing was carried out at different temperatures using two heated seal sandwiches with a seal pressure of 2 bar and a seal time of 0.5 seconds. After the sealed sample was cut into a width of 15 mm, the seal seam strength was measured by a T-type peel test under the same conditions as described above. The temperature when the seal seam strength reached 0.5 N / 15 mm was defined as the minimum seal temperature.

(7) Haze:
The haze of the film was measured according to ASTM-D 1003-52.

(8) Gross value:
The gloss value was measured according to DIN 67530. Reflectance was measured as an optical property of the film surface. Based on ASTM-D 523-78 and ISO 2813, the incident angle was 20 ° (glossy surface) or 60 ° (matte surface).

(9) Standard viscosity SV:
The standard viscosity SV (DCA) of the polyester was measured according to DIN 53726 at 25 ° C. in dichloroacetic acid. The intrinsic viscosity IV of the polyester was calculated from the following equation using the standard viscosity SV value.

IV = [η] = 6.907 · 10 ⁻⁴ SV (DCA) +0.063096 [dl / g]

(10) Friction coefficient:
The coefficient of friction was measured according to DIN 53375 14 days after production.

(11) Weather resistance (both surfaces), UV resistance:
The ultraviolet resistance was tested by the method shown in ISO 4892 under the conditions shown in Table 2 below.

(12) Color difference:
The color difference was measured using the spectrometer according to DIN 5033 with respect to the film which tested the said weather resistance. The greater the deviation from the reference, the greater the color difference. A color difference value of 0.3 or less indicates that there is no noticeable color difference.

(13) Yellowing index:
For yellowing index (YID), the deviation of color in the yellow direction was measured according to DIN 6167. When the yellowing index is less than 5, no yellowing is observed visually.

(14) Evaluation of processing characteristics:
The processing characteristics of the film were evaluated by the following criteria by laminating a film on a steel plate.

(15) Film break in the manufacturing process:
In the film production process, the number of breaks of the film per unit time was compared with the number of breaks of the film in the production of a known film, and expressed in%.

Example 1:
The polyethylene terephthalate chips shown in Table 4 below were dried at 150 ° C. so that the water content was less than 100 ppm, and charged into an extruder for base layer B. Further, the copolymer polyester containing polyethylene terephthalate and silica particles shown in Table 4 below was dried in the same manner and charged into an extruder for the matte outer layer C.

  Separately from this, as a polyester for the sealing outer layer A, manganese is used as a catalyst for the transesterification reaction (manganese concentration: 100 ppm), and a straight chain consisting of 78 mol% of ethylene terephthalate units and 22 mol% of ethylene isophthalate units. Copolyester was obtained by transesterification. The obtained copolyester was dried at 100 ° C. to make the water content less than 200 ppm, and then supplied to the extruder for the sealing outer layer A.

  After co-extrusion, the film was stretched in the longitudinal and transverse directions under the conditions shown in Table 5 below, and further heat-set to obtain an ABC type three-layer transparent laminated film having a total thickness of 25 μm. The configuration of each layer is shown in Table 4 below.

  The film production conditions are shown in Table 5 below.

  The resulting film had the desired low gloss, low haze and excellent sealing properties. In addition, the film could be easily produced without increasing the number of breaks of the film. The film had the desired operational and processing characteristics. Table 7 shows the composition of the film and the evaluation results.

  Further, regarding the weather resistance (both surfaces) and ultraviolet resistance of the film (also in the following examples and comparative examples), in accordance with the ISO 4892 method described above, using an Atlas Ci 65 Weather-Ometer, the weather resistance was 1000 hours. A sex test was performed. The resulting film was again measured for mechanical properties, coloration, surface defects, haze and gloss. From the obtained results, it was confirmed that the performance before the weather resistance test was almost maintained.

Example 2:
A film was prepared in the same manner as in Example 1 except that the thickness of the sealing outer layer A was changed from 1.5 μm to 2.0 μm and the thickness of the base layer was changed from 22.0 μm to 21.5 μm. The resulting film had improved sealing properties. In particular, the seal seam strength has been greatly improved. Table 7 shows the composition of the film and the evaluation results.

Example 3:
The same operation as in Example 1 was conducted except that the thickness of the sealing outer layer A was changed to 2.5 μm, the thickness of the base layer B was changed to 20.5 μm, and the thickness of the matte outer layer C was changed to 2.0 μm. A film was created. The resulting film had improved sealing properties. In addition, the matte property was slightly improved. Table 7 shows the composition of the film and the evaluation results.

Example 4:
Example 1 except that the configuration of the matte outer layer C is changed as shown in the following table, the thickness of the base layer B is changed to 21.5 μm, and the thickness of the matte outer layer C is changed to 2.0 μm. A film was prepared in the same manner as described above. Table 7 shows the composition of the film and the evaluation results.

Example 5:
The polyethylene terephthalate chip and polyethylene terephthalate containing an ultraviolet stabilizer shown in Table 8 below were dried at 150 ° C. so that the water content was less than 100 ppm, and charged into an extruder for base layer B. Further, polyethylene terephthalate shown in Table 8 below, polyethylene terephthalate containing an ultraviolet stabilizer, and copolymerized polyester containing silica particles were similarly dried and put into an extruder for the matte outer layer C.

  Separately from this, as a polyester for the sealing outer layer A, manganese is used as a catalyst for the transesterification reaction (manganese concentration: 100 ppm), and a straight chain consisting of 78 mol% of ethylene terephthalate units and 22 mol% of ethylene isophthalate units. Copolyester was obtained by transesterification. The obtained copolyester was dried at 100 ° C. to make the water content less than 200 ppm, and then supplied to the extruder for the sealing outer layer A.

  As the UV stabilizer used above, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxyphenol (Tinvin (registered trademark) 1577) was used as a master batch. Was added in the form of The masterbatch consisted of 20% by weight Tinuvin 1577 and 80% by weight polyethylene terephthalate. The compounding amount of the master batch is shown in Table 8 below.

  After co-extrusion, the film was stretched in the longitudinal and transverse directions under the same conditions as in Examples 1 to 4, and further heat-set to obtain an ABC type three-layer transparent laminated film having a total thickness of 25 μm. The structure of each layer is shown in Table 8 below.

  The resulting film had the desired low gloss, low haze and excellent sealing properties. In addition, the film could be easily produced without increasing the number of breaks of the film. The film had the desired operational and processing characteristics. Table 11 shows the composition of the film and the evaluation results.

  Further, regarding the weather resistance (both surfaces) and ultraviolet resistance of the film (also in the following examples and comparative examples), in accordance with the ISO 4892 method described above, using an Atlas Ci 65 Weather-Ometer, the weather resistance was 1000 hours. As a result of performing the property test, the mechanical properties, coloring, surface defects, haze and gloss of the obtained film were measured again. From the obtained results, it was confirmed that the performance before the weather resistance test was almost maintained.

Example 6:
A film was prepared in the same manner as in Example 5 except that the thickness of the sealing outer layer A was changed from 1.5 μm to 2.0 μm and the thickness of the base layer was changed from 22.0 μm to 21.5 μm. The resulting film had improved sealing properties. In particular, the seal seam strength has been greatly improved. Table 11 shows the composition of the film and the evaluation results.

Example 7:
The same operation as in Example 5 was performed except that the thickness of the sealing outer layer A was changed to 2.5 μm, the thickness of the base layer B was changed to 20.5 μm, and the thickness of the matte outer layer C was changed to 2.0 μm. A film was created. The resulting film had improved sealing properties. In addition, the matte property was slightly improved. Table 11 shows the composition of the film and the evaluation results.

Example 8:
Example 5 except that the configuration of the matte outer layer C is changed as shown in the following table, the thickness of the base layer B is changed to 21.5 μm, and the thickness of the matte outer layer C is changed to 2.0 μm. A film was prepared in the same manner as above. Table 11 shows the composition of the film and the evaluation results.

Comparative Example 1:
In Example 5, a film was produced in the same manner as in Example 1 except that the structure of the sealing outer layer A was changed as shown in the following table. Although this film has slightly improved winding properties and processing characteristics, its sealing properties and optical properties are greatly deteriorated. Table 12 shows the composition and evaluation results of the film.

Comparative Example 2:
Example 1 of European Patent Publication No. 0035835 was additionally tested. The obtained film was greatly inferior to the examples of the present invention in terms of sealing properties, optical properties and film breaking properties. Moreover, the haze of the film was high. Table 12 shows the composition and evaluation results of the film.

Comparative Example 3:
Example 1 of European Patent Publication No. 1219413 was additionally tested. The obtained film was greatly inferior to the examples of the present invention in terms of sealing properties, optical properties and film breaking properties. Moreover, the haze of the film was high. Table 12 shows the composition and evaluation results of the film.

Figure showing the relationship between the content of isophthalic acid units in polyester and the stretching stress It shows the d ₅₀ of the cumulative particle size distribution curve of the particles It shows the _{d 98} and _{d 10} of the cumulative particle size distribution curve of the particles Schematic diagram showing measurement of seal seam strength by 180 ° peeling method

Explanation of symbols

1: Film 2: APET / CPET tray 3: Jig

Claims (14)

A sealing matte biaxially stretched laminated polyester film comprising a base layer B, a sealing outer layer A, and another matting outer layer C located on the opposite side of the outer layer A with respect to the base layer B, a) Sealable outer layer A contains particles in an amount of 0.01% by weight or less based on the weight of sealable outer layer A, and b) Matte outer layer C contains 6-30 mol% isophthalic acid units. Particles comprising a copolymerized polyester and having an average particle size d ₅₀ of 2 to 10 μm and a particle size distribution represented by the SPAN 98 method of 1.2 to 2, based on the weight of the matte outer layer C A sealing matte biaxially stretched laminated polyester film comprising 1.0 to 7.0% by weight.   The polyester film according to claim 1, wherein the haze of the film is less than 45%.   The polyester film according to claim 1 or 2, wherein the base layer B comprises a thermoplastic polyester.   The polyester film according to any one of claims 1 to 3, wherein 90 mol% or more of the polyester constituting the base layer B comprises an ethylene terephthalate unit or an ethylene-2,6-naphthalate unit.   The polyester film according to any one of claims 1 to 4, wherein the polyester constituting the base layer B is ethylene terephthalate.   The polyester film according to any one of claims 1 to 5, wherein the sealing outer layer A is made of a copolyester composed of ethylene terephthalate units and ethylene isophthalate units.   The polyester film according to claim 6, wherein the copolyester constituting the sealing outer layer A is a copolyester comprising 60 to 95 mol% of ethylene terephthalate units and 40 to 5 mol% of ethylene isophthalate units. The polyester film according to claim 1, wherein the particles contained in the matte outer layer C are SiO ₂ particles.   The polyester film according to any one of claims 1 to 8, wherein the sealing outer layer A substantially does not contain particles.   The polyester film according to claim 1, wherein the sealing outer layer A has a thickness of 0.5 to 10 μm.   The polyester film according to any one of claims 1 to 10, wherein the minimum heat sealing temperature of the sealing outer layer A with respect to the APET substrate is 140 ° C or lower.   The polyester film according to any one of claims 1 to 11, wherein the gloss value of the surface on the sealable outer layer A side at an incident angle of 20 ° exceeds 130.   Furthermore, the polyester film in any one of Claims 1-12 which contains a ultraviolet stabilizer in the base layer B and the matte outer layer C.   A method for producing a sealing matte biaxially stretched laminated polyester film according to any one of claims 1 to 13, wherein the production method comprises a coextrusion method for sealing outer layer A, base layer B and matting outer layer. The method comprises a step of obtaining a laminated sheet comprising C, a step of biaxially stretching the obtained laminated sheet to obtain a biaxially stretched film, and a step of thermally fixing the obtained biaxially stretched film. A method for producing a sealing matte biaxially stretched laminated polyester film.