JP2006015675A - Laminated polyester film for building material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated polyester film for a building material showing excellent peeling resistance between boundary surfaces of the laminated film. <P>SOLUTION: In the laminated polyester film for the building material made by mounting a polyester layer (layer A) composed of a polyester a having a melting point of not higher than 250°C on one surface or both surfaces of a polyester layer (layer B) containing the polyester a having a melting point of not higher than 250°C, a surface orientation coefficient fn measured from the surface side of the layer A is not bigger than 0.08, and a diameter χc of a crystalline particle of the whole laminated polyester film is not smaller than 6.0. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminated polyester film for building materials. More specifically, the present invention relates to a laminated polyester film for building materials having excellent peel resistance at the film laminate interface.

  In recent years, there has been an increasing need for cost reduction in residential construction, and there has been an increasing demand for lower costs for building materials. At the same time, it is also important to improve the functionality for countermeasures against sick house syndrome, which is becoming a major social problem, and to make non-timber as a countermeasure against natural destruction by deforestation. Currently, materials such as polyvinyl chloride, polyolefin sheets, polyester or resin-impregnated paper are used as building materials such as wallpaper materials, laminated steel plate materials, and plywood materials. Above all, biaxially oriented polyester films have excellent properties such as dimensional stability, mechanical properties, heat resistance, transparency, electrical properties, and chemical resistance. Widely used as a material film.

  However, in general, the biaxially oriented polyester film has a defect that its surface is highly crystallized and therefore has poor adhesion to various coatings. For this reason, conventionally, studies have been made to give adhesion to the surface of the polyester film by various methods.

  Conventionally, as an example of a method for imparting adhesiveness to the surface of a polyester film, a method of providing various resins such as an acrylic resin, a polyester resin, a urethane resin, or a polyolefin resin having adhesiveness on the film surface is known. (See Patent Document 1). Also, a layer in which two types of specific polyester resins having different glass transition temperatures are blended to form a surface having good adhesion to a curable ink and a water-soluble resin on a polyester film. Has been proposed (see Patent Document 2). Furthermore, it is known that a polyester film obtained by laminating a low-melting polyester as an adhesive layer exhibits, for example, a laminating property with a metal (see Patent Document 3).

However, a laminated polyester provided with a low-melting polyester layer as an adhesive layer is peeled off at the laminated interface in a building material that requires a strong adhesive force in a harsh environment such as high temperature and high humidity. In many cases, the desired function could not be exhibited.
JP-A-60-198240 JP 2002-337287 A JP-A-5-42643

  In view of this situation, an object of the present invention is to provide a laminated polyester film for building materials that improves such drawbacks and has excellent peel resistance at the film lamination interface.

  In order to achieve this object, the laminated polyester film for building materials of the present invention has the following constitution. That is, the laminated polyester film for building materials of the present invention is a polyester composed of polyester a having a melting point of 250 ° C. or lower on one side or both sides of a polyester layer (B layer) containing polyester a having a melting point of 250 ° C. or lower. A laminated polyester film for building materials provided with a layer (A layer) having a plane orientation coefficient fn measured from the surface side of the A layer of 0.08 or less, and crystal grains of the entire laminated polyester film A laminated polyester film for building materials, characterized in that the value of the diameter χc is 6.0 or more.

And the laminated polyester film for building materials of this invention has the following preferable aspect.
(a) The polyester a having a melting point of 250 ° C. or lower is a copolymerized polyester containing at least one of isophthalic acid and 1,4-cyclohexanedimethanol as a copolymerization component.
(b) The content of the polyester a having a melting point of 250 ° C. or less contained in the B layer is 0.1% by weight or more based on the total of the polyesters forming the B layer.
(c) The thickness of the A layer is 50 μm or less.
(d) A laminated film layer (C layer) containing polyester is provided on at least one side of the laminated polyester film.
(e) The polyester contained in the C layer is a copolymer polyester having isophthalic acid and diethylene glycol as copolymer components.
(f) The polyester contained in the C layer is 10 to 60% by weight based on the total amount of resins forming the C layer.
(g) The C layer is a coating layer formed of components that can be applied with an aqueous coating liquid and stretched in at least one direction, and the thickness of the coating layer is 0.01 to 2 μm.
(h) The total thickness of the laminated polyester film is 100 to 500 μm.
(i) A Ti-based polymerization catalyst is included in at least one of the A layer and the B layer.

  According to the present invention, since the peel resistance at the film lamination interface is dramatically improved, the laminated polyester film that has not been used so far due to the peeling at the film lamination interface in a harsh environment can be used as wallpaper, plywood. It can be suitably used as a base material for building materials such as flooring materials and floor heating materials.

  Hereinafter, the laminated polyester film for building materials of the present invention will be described in more detail.

  In the present invention, although it is not particularly limited for building materials, for example, as a part of a base material constituting a general house or a high-rise building such as wallpaper, plywood, flooring material and floor heating material, both films It is used by adhering other materials to each surface. The present invention provides a laminated polyester film for building materials suitable as such a substrate.

  The laminated polyester film for building materials according to the present invention comprises a polyester layer (B layer) containing polyester a having a melting point of 250 ° C. or lower, a layer (A layer) composed of polyester a having a melting point of 250 ° C. or lower, and Preferably it consists of each layer of the laminated film layer (C layer) containing polyester, The preferable layer structure is as follows.

  That is, the A layer is laminated on the surface of one side or both sides of the B layer, and when the A layer is only on one side of the B layer, the C layer is provided on the opposite side of the A layer, or the A layer Is a laminated structure in which the C layer is provided on one side of the A layer. A specific layer structure composed of the A layer to the C layer can be represented by a laminated structure of A layer / B layer / C layer and a laminated structure of A layer / B layer / A layer / C layer.

  The polyester used in the present invention is a polymer compound having an ester bond as the main bond chain of the main chain, and can be obtained by polycondensation of dicarboxylic acid and diol. Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, diphenylcarboxylic acid, diphenylsulfone dicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sodium sulfoisophthalic acid, phthalic acid and other aromatic dicarboxylic acids, oxalic acid, and succinic acid. , Eicoic acid, adipic acid, sebacic acid, dimer acid, dodecanedioic acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids, trimellitic acid, and pyromellitic acid, etc. A polyfunctional acid etc. can be mentioned. On the other hand, examples of the diol component include aliphatic glycols such as ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, neopentyl glycol and triethylene glycol, aromatic glycols such as bisphenol A and bisphenol S, diethylene glycol, And polytetramethylene glycol.

  In the polyester, various additives such as antioxidants, heat stabilizers, weathering stabilizers, UV absorbers, organic lubricants, organic and inorganic particles, pigments, dyes, fillers, antistatic agents. Further, a nucleating agent or the like may be added within a range not impairing the effects of the present invention.

  Further, as a polymerization catalyst, a Ti catalyst (for example, titanium alkoxides such as titanium tetrabutoxide and titanium tetraisopropoxide, composite oxides and titanium complexes in which the main metal element is composed of titanium and silicon, etc.) Using 0.0005 to 0.15% by weight in terms of titanium atom to the obtained polyester) is preferable because the aggregates are reduced. The polyester thus obtained contains a Ti catalyst, and in some cases, the polymerization catalyst function may be deactivated.

  In the present invention, it is necessary for achieving the object of the present invention that the value of the plane orientation coefficient fn measured from the surface side of the A layer is 0.08 or less, more preferably 0.065 or less. That is, by reducing the degree of orientation of the film surface, the adhesion with various coatings is improved, and at the same time, the degree of orientation at the interface between the A layer and the B layer is lowered, thereby improving the affinity between the two layers. This is because the peel resistance at the interface is improved. When this plane orientation coefficient exceeds 0.08, the adhesiveness fall with various coating materials, the peeling in a lamination | stacking interface, etc. will arise. The lower limit of the plane orientation coefficient is not particularly limited, but is preferably 0.02 or more from the viewpoint of film formation stability and film transportability.

  In addition, in the laminated polyester film for building materials of the present invention, the value of the crystal particle diameter χc measured for the whole film is 6.0 or more, and more preferably 7.0 or more in order to achieve the object of the present invention. Is necessary. That is, the crystallinity increases, so that the affinity at the laminated interface is improved and the peel resistance at the laminated interface is improved. Further, the upper limit value of the crystal particle diameter χc is not particularly limited, but if the crystallinity is too high, the film forming stability is lowered, and therefore it is preferably 15.0 or less.

  In the present invention, the organic or / and inorganic particles are also contained in the A layer, the B layer, and more preferably the C layer when the laminated polyester film for building materials of the present invention is used as a slippery film roll. It is suitable for improving the blocking resistance.

  Examples of the organic particles contained in the laminated polyester film for building materials of the present invention include cross-linked polystyrene, cross-linked acrylic resin, melamine resin, and benzoguanamine resin. As the inorganic particles, for example, silica, colloidal silica, beaded silica, alumina, alumina sol, kaolin, talc, mica, clay, calcium carbonate, metal oxide (such as tin oxide) and the like are preferably used. These organic particles and inorganic particles preferably have an average particle size of 0.001 to 6 μm, and more preferably 0.01 to 5 μm.

  The content of the particles is not particularly limited, but in the A layer, 0.0001 to 30% by weight with respect to the total resin forming the A layer, and in the B layer, the total resin forming the B layer. On the other hand, 0.001 to 50% by weight, and in the C layer, 0.0001 to 30% by weight with respect to the total of the resins forming the C layer can be mentioned as preferable ranges.

  The total thickness of the laminated polyester film for building materials of the present invention is appropriately selected according to the application for which the film of the present invention is used, but from the viewpoint of mechanical strength, handling properties and productivity, preferably 100 to It is 500 micrometers, More preferably, it is 120-400 micrometers.

  In the present invention, the A layer is a layer laminated on at least one side of the B layer, and the polyester constituting the A layer is a polyester a having a melting point of 250 ° C. or lower. The preferable range of the melting point is 160 to 250 ° C, more preferably 170 to 245 ° C. If the melting point is too low, the polymer tends to stick and handleability is lowered, and the surface of the film is easily scratched. When the melting point exceeds 250 ° C., the adhesion during lamination becomes poor.

  Polyester a having a melting point of 250 ° C. or lower constituting the A layer may be used singly or in combination of two or more, but is 75% by weight or more based on the total of the resins constituting the A layer. Is preferably the above polyester a, more preferably 80% by weight or more. If the amount of the polyester is small, the adhesion to various coatings may be inferior, or the peel resistance at the interface between the A layer and the B layer may be lowered. The resin constituting the A layer other than the polyester a is not particularly limited as long as the effects of the present invention are not impaired, and other polyester resins can be preferably used. For example, polyethylene terephthalate, Examples thereof include waste polyester produced in the production process of the polyester film.

  Polyester a having a melting point of 250 ° C. or lower includes, for example, isophthalic acid, 1,4-cyclohexanedimethanol, terephthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, decanedicarboxylic acid as copolymerization components. Preferred is a copolyester containing at least one selected from the group consisting of acid, azelaic acid, dodecadicarboxylic acid and cyclohexanedicarboxylic acid, and particularly preferred is a copolyester containing isophthalic acid or 1,4-cyclohexanedimethanol. And from the viewpoint of performance. As other copolymerization components, known dicarboxylic acids and diols can be used. Examples of known diols include, but are not limited to, ethylene glycol, butanediol, hexanediol, neopentyl glycol, decanediol, neopentyl glycol, diethylene glycol, triethylene glycol, and polyethylene glycol. is not.

  The thickness of the A layer is preferably 50 μm or less, more preferably 25 μm or less, and most preferably 10 μm or less. When the thickness of the A layer is larger than 50 μm, the economy and film forming property may be inferior, or the peel resistance may be lowered. Further, the lower limit value of the thickness of the A layer is not particularly limited, but if the thickness of the A layer is too thin, the adhesion to the coating may be inferior, and it is preferably 1 μm or more.

  The polyester layer (B layer) of the laminated polyester film for building materials of the present invention contains polyester a having a melting point of 250 ° C. or lower. The polyester a having a melting point of 250 ° C. or lower contained in the B layer may be used alone or in combination of two or more, but the polyester a having a melting point of 250 ° C. or lower forming the A layer The same kind is preferable. By containing the same kind of polyester as the polyester forming the A layer in the B layer, the affinity of the interface between the A layer and the B layer is increased, and the peel resistance can be improved.

  The content of the polyester a having a melting point of 250 ° C. or less contained in the B layer is preferably 0.1% by weight or more, more preferably 0.1% by weight or more based on the total of all the polyesters forming the B layer. 50% by weight, most preferably 0.1-30% by weight. If the content is too small, the peel resistance at the interface between the A layer and the B layer may be reduced, and if the content is too large, the economy and productivity may be inferior. Moreover, as a method of making the B layer contain polyester a having a melting point of 250 ° C. or lower, it may be copolymerized or blended.

  The polyester constituting the B layer other than the polyester a having a melting point of 250 ° C. or lower is not particularly limited, but preferably includes, for example, waste polyester produced in the production process of polyethylene terephthalate or a general polyester film. Can do. In forming the B layer, the total of the polyester a having a melting point of 250 ° C. or less and the other polyester is preferably 80% by weight or more, more preferably 85% by weight or more based on the total of the resins forming the B layer. The resin other than the polyester resin constituting the B layer is not particularly limited as long as the effects of the present invention are not impaired. For example, acrylic resin, urethane resin, epoxy resin, silicone resin, urea resin And phenol resin.

  In the laminated polyester film for building materials of the present invention, the base film portion composed of the B layer and the A layer is preferably biaxially oriented. The biaxially oriented polyester film generally stretches an unstretched polyester sheet or film about 2.5 to 5 times in the longitudinal direction (longitudinal direction) and in the direction perpendicular to the longitudinal direction (transverse direction). After that, heat treatment is performed, crystal orientation is completed, and a biaxial orientation pattern is shown by wide angle X-ray diffraction.

  The laminated film layer (C layer) in the present invention is preferably provided on one surface of the base film composed of the B layer and the A layer. More specifically, a laminated film layer (C layer) containing polyester is provided on one side of the laminated polyester film for building materials, and at least the A layer on the opposite side of the B layer from which the C layer is provided. It is preferable to have. That is, in the case of A layer / B layer where the A layer is only on one side of the B layer, the C layer is provided on the surface opposite to the A layer, and the A layer is on both sides of the B layer. In the case of A layer / B layer / A layer, a C layer is provided on one surface of the A layer.

  The layer C is preferably a coating layer formed by stretching in at least one direction after applying the aqueous coating liquid from the viewpoint of environmental pollution prevention and explosion-proof properties during film production. It is preferable that the base film is formed within a manufacturing process for biaxial orientation. Although the timing of the stretching is not particularly limited, a method of biaxial stretching after applying the aqueous coating liquid, or a method of applying the aqueous coating liquid after longitudinal (longitudinal direction of the film) and further laterally stretching is preferably used. As the coating method of the aqueous coating liquid, various coating methods such as reverse coating method, gravure coating method, rod coating method, bar coating method, die coating method and spray coating method can be preferably used, but are not limited thereto. Is not to be done.

  In order to apply as an aqueous coating liquid, the polyester contained in the C layer is preferably a copolymer polyester containing a compound containing a sulfonate group or a compound containing a carboxylate group as a copolymer component. Examples of the compound containing a sulfonate group include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and alkali metal salts and alkaline earth metals thereof. Salts and ammonium salts can be used, but are not limited thereto. Examples of the compound containing a carboxylate group include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-methylcyclohexene-1,2,3-tricarboxylic acid, trimesic acid, 1,2,3 , 4-Butanetetracarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-cyclohexene-1,2-dicarboxylic acid, cyclopentanetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic Acid, 1,2,5,6-naphthalenetetracarboxylic acid, ethylene glycol bistrimellitate, 2,2 ′, 3,3′-diphenyltetracarboxylic acid, thiophene-2,3,4,5-tetracarboxylic acid, Ethylenetetracarboxylic acid, or alkali metal salts, alkaline earth metal salts and ammonium salts thereof. It can be used, but are not limited thereto.

  The polyester contained in the C layer is preferably a copolymer polyester containing isophthalic acid and diethylene glycol as copolymer components. By using this component as a copolymer component, the solvent resistance of the C layer, particularly with respect to alcohol, can be improved, and when the A layer and the B layer contain polyester having a copolymer component of isophthalic acid, The adhesive force at the C layer or at the interface between the B layer and the C layer can be improved. The amount of isophthalic acid as the copolymer component is preferably 65 to 95 mol%, more preferably 70 to 95 mol%. The amount of diethylene glycol as the copolymer component is preferably 50 to 95 mol%, more preferably 60 to 90 mol%. As other copolymerization components, known dicarboxylic acids and diols can be used. Examples thereof include, but are not limited to, the dicarboxylic acids and diols described above. Moreover, the compound containing an above described sulfonate group and the compound containing a carboxylate group can also be included as a copolymerization component. The range of the preferable glass transition point of this copolyester is 0-60 degreeC, More preferably, it is 10-45 degreeC.

  The content of the copolyester containing isophthalic acid and diethylene glycol as a copolymerization component is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, based on the total amount of resins forming the C layer. If the content is too small, the solvent resistance and the adhesive strength with the A layer and the B layer may be inferior. If the content is too large, the blocking resistance may be inferior when used as a film roll.

  The resin other than the copolymerized polyester having isophthalic acid and diethylene glycol as the copolymerization component forming the C layer is not particularly limited as long as the effects of the present invention are not impaired. For example, other polyester resins, acrylic resins , Urethane resin, epoxy resin, silicone resin, urea resin, phenol resin, and the like, and other polyester resins are particularly preferable.

  The thickness of the C layer is preferably 0.01 to 2 μm, more preferably 0.05 to 1 μm. If the thickness of the C layer is too thin, adhesion to various coatings and solvent resistance may be insufficient, and if it is too thick, the slip resistance and blocking resistance when used as a film roll may be reduced.

  The laminated polyester film for building materials of the present invention comprises a polyester layer (B layer) containing polyester a having a melting point of 250 ° C. or lower and a polyester layer (A layer) composed of polyester a having a melting point of 250 ° C. or lower. After laminating in the melt-extrusion process, a laminated film layer (C layer) containing polyester is formed by means of applying a coating solution on one side thereof, and further uniaxially or biaxially stretched as necessary. Although it can manufacture by the method of heat-processing, the adhesiveness with a coating can be improved significantly by performing the heat processing at the temperature more than melting | fusing point of the polyester which comprises A layer. Furthermore, by this heat treatment, the improvement of the affinity of the laminated interface and the improvement of the crystallinity are achieved at the same time due to the decrease in the orientation degree of the interface between the A layer and the B layer, which is the main point of the present invention.

  The means for performing the heat treatment at the specific temperature is not particularly limited as long as the crystal orientation on the surface of the A layer is partially broken to achieve the effect of the present invention. For example, in a production process in which a film is biaxially oriented, a method in which heat treatment is performed subsequent to stretching in the vertical and horizontal directions can be mentioned as a preferable method in terms of economy and productivity. Moreover, after winding up a biaxially oriented film, the method of heat-processing again is also possible.

  Next, although the manufacturing method of the laminated polyester film for building materials of this invention is demonstrated in detail, this invention method is not limited to this.

  The polyester pellets for layer A and the polyester pellets for layer B prepared in advance so as to have a predetermined polymer composition are vacuum-dried and then supplied to two extruders for layer A and layer B, at 200 to 300 ° C. After the A layer is laminated on one or both sides of the B layer, it is extruded in a molten state from a T-shaped die, and is cast at a surface temperature of 10 to 60 ° C. using an electrostatic charge method. It is wound around a drum and cooled and solidified to produce an unstretched polyester film. Subsequently, the unstretched film is stretched 2.5 to 5 times in the longitudinal direction (longitudinal direction) of the film between rolls heated to a temperature of 60 to 120 ° C. Subsequently, on one side of the film (that is, when the A layer is only on one side of the B layer, on the surface opposite to the A layer, and when the A layer is on both sides of the B layer) A corona discharge treatment is performed on one surface of the A layer, and an aqueous coating liquid for forming the C layer is applied. Subsequently, the coated film is gripped with a clip, guided to a hot air zone heated to a temperature of 70 to 150 ° C., dried, and then 2.5 to 5 in a direction perpendicular to the longitudinal direction (lateral direction). The film is double-stretched and subsequently introduced into a heat treatment zone having a temperature equal to or higher than the melting point of the polyester constituting the A layer, and heat treatment is performed for about 1 to 50 seconds. In this heat treatment step, a relaxation treatment of 3 to 12% may be performed in the width direction or the longitudinal direction as necessary. Biaxial stretching may be performed by simultaneous biaxial stretching in addition to the above-described longitudinal and transverse sequential stretching, and may be performed by a method of re-stretching in either the longitudinal or transverse direction after longitudinal and transverse stretching. Also good.

  In the method of the present invention, the heat treatment performed after biaxial stretching is performed at a temperature of 240 ° C. or higher corresponding to the melting point or higher when a polyester layer having a melting point of 240 ° C. is used for the A layer. It is preferable to carry out at a temperature of about 5 ° C. higher than the melting point. The upper limit value of the heat treatment temperature is appropriately determined in relation to the heat treatment time, but in practice it is about 255 ° C. at the highest.

[Characteristic measurement method and effect evaluation method]
The characteristic measurement method and effect evaluation method in the present invention are as follows.

(1) Melting point of polyester, glass transition point It was measured by connecting an SSC 5200 disk station (manufactured by Seiko Electronics Industry) to a robot DSC (differential scanning calorimeter) RDC220 (manufactured by Seiko Electronics Industry). 10 mg of the sample was adjusted to an aluminum pan, set in a DSC apparatus (reference: aluminum pan of the same type without a sample), heated at a temperature of 300 ° C. for 5 minutes, and then rapidly cooled using a liquid nitrogen atmosphere . DSC measurement was performed while heating the sample at 10 ° C./min. From the obtained DSC chart, the melting point was changed from the peak temperature based on crystal melting, and the temperature was changed from the temperature based on the transition from the glass state to the rubber state. I read the points.

(2) Thickness of each layer of laminated film Using a transmission electron microscope H-7100FA type (manufactured by Hitachi, Ltd.), the thickness was obtained from a photograph observing the cross section of the laminated polyester film. The thickness was an average value of 5 points in the measurement visual field.

(3) Peeling resistance at the interface of the laminated film An adhesive layer is applied on the A layer, a film that strongly adheres to the adhesive layer is bonded to the other layer, cut into 25 mm × 200 mm, and further at a temperature of 80 ° C. The sample was allowed to stand for 7 days. The laminate interface was forcibly peeled off at a 180 ° angle and a peeling speed of 0.3 m / min using a tensile tester (TONSILON / UTM-4-100 manufactured by TOYO BALDWIN CO. LTD). When the force required for peeling is 75N / 25mm or more, ◎, when 65N / 25mm or more and less than 75N / 25mm, ○, and when the force is 55N / 25mm or more and less than 65N / 25mm, Δ, 45N / 25mm or more Those with less than 55 N / 25 mm were evaluated as x, and those with less than 45 N / 25 mm were determined as xx.

(4) Plane orientation coefficient fn measured from the surface side of layer A
Refractive indices in the longitudinal direction, width direction and thickness direction (each nx) with an Abbe refractometer NAR-4T (manufactured by Atago Co., Ltd.) using sodium D-line (wavelength 589 nm) as a light source and methylene iodide as a mounting solution. , Ny, nz). The surface distribution coefficient fn was obtained by calculating fn = (nx + ny) / 2−nz.

(5) Crystal grain size χc of the entire laminated polyester film
Using an X-ray diffractometer PW-1820 (manufactured by PHILIPS), the crystal particle diameter χc of the (100) plane was determined by reflection X-ray diffraction using the Scherrer equation. Here, the measured X-ray wavelength was 0.15418 nm (CuKα), and diffraction on the (100) plane was observed at a Bragg angle of about 12.7 °.

The present invention will be described based on the following examples, but the present invention is not limited to these examples.
Example 1
Using a composite film forming apparatus having an extruder (A), an extruder (B), and a T-die composite die, a laminated polyester film composed of an A layer and a B layer was obtained as follows. First, in order to form the A layer, polyethylene terephthalate containing 0.05% by weight of silica having an average particle diameter of 4.0 μm and 17.5% by weight of isophthalic acid as a copolymer component with respect to the entire resin constituting the A layer. (Melting point: 216 ° C., polyester a in the present invention, hereinafter abbreviated as low melting point polyester (1)) 75.0% by weight (polyester obtained from ethylene glycol slurry of citrate chelate titanium compound as polymerization catalyst) The raw material containing 25.0% by weight of polyethylene terephthalate (melting point: 255 ° C., hereinafter abbreviated as PET) used in an amount of 0.01% by weight in terms of titanium atom was vacuum-dried and then extruded. It was supplied to the machine (A) side, melted at a temperature of 280 ° C. by a conventional method, and introduced into the T-die composite die.

  On the other hand, since the B layer is formed, the low melting point polyester (1) is 10.0% by weight with respect to the entire resin constituting the B layer (an ethylene glycol slurry of a citrate chelate titanium compound can be obtained as a polymerization catalyst). The raw material containing 90.0% by weight of PET (which was used to be 0.01% by weight in terms of titanium atom with respect to the polyester) was vacuum-dried and then supplied to the extruder (B) side. It was melted at a temperature of 280 ° C. and introduced into a T-die composite die. Next, the polyester layer (A) was joined so as to be laminated on one side of the polyester layer (B) in the die, and then co-extruded into a sheet to obtain a melt-laminated sheet. Then, the laminated sheet was closely cooled and solidified by an electrostatic charge method on a casting drum maintained at a surface temperature of 22 ° C. to obtain an unstretched laminated polyester film. Subsequently, the unstretched laminated polyester film is preheated with a roll group heated at a temperature of 78 ° C. according to a conventional method, and then stretched 2.8 times in the longitudinal direction (longitudinal direction) using a heating roll at a temperature of 95 ° C. And cooled with a roll group at 21 ° C. to obtain a uniaxially stretched laminated polyester film. Subsequently, the surface opposite to the laminated surface of the uniaxially stretched laminated polyester film is subjected to corona discharge treatment in the air, and the following coating layer forming coating solution (C layer forming coating solution) is applied to the treated surface as a metering bar. The C layer was formed by coating by a bar coating method using While holding both ends of the uniaxially stretched laminated polyester film coated with this coating layer forming coating liquid with clips, it is guided to a preheating zone at a temperature of 130 ° C. in the tenter, and then continuously in a heating zone at a temperature of 135 ° C. in the longitudinal direction. The film was stretched 3.2 times in the direction perpendicular to the surface (lateral direction). Subsequently, a heat treatment at a temperature of 240 ° C. was performed in a heat treatment zone in the tenter, and further a relaxation treatment was performed in a 2% lateral direction at 235 ° C., followed by a further 2% relaxation treatment at a temperature of 150 ° C. After being cooled, it was wound up to obtain a laminated polyester film. The properties of the laminated polyester film thus obtained are as shown in Table 1, and it can be seen that the peel resistance is excellent.

[C layer forming coating solution]
(A) Fluorosurfactant (B) Colloidal silica (average particle size 1.0 μm)
(C) Copolyester having a copolymer composition of terephthalic acid / 5-sodium sulfoisophthalic acid // ethylene glycol (molar ratio 87.5 / 12.5 // 100) (glass transition point 40 ° C.)
(D) Copolyester having a copolymer composition of isophthalic acid / 5-sodium sulfoisophthalic acid // ethylene glycol / diethylene glycol (molar ratio 93/7 // 10/90) (glass transition point 18 ° C.)
The above (C) / (D) is mixed at a solid content weight ratio of 70/30, diluted with water to a solid content concentration of 4 wt%, and (A) is 0.0003 wt. %, (B) is added in an amount of 0.006% by weight based on the entire coating liquid.

(Examples 2-3)
A laminated polyester film was obtained in the same manner as in Example 1 according to the composition and conditions shown in Table 1. The part which is not mentioned in particular carries out the same method as in Example 1. The characteristics of the obtained laminated polyester film are as shown in Table 1, and it can be seen that it has excellent peel resistance. The low melting point polyester (2) is a polyethylene terephthalate (melting point: 218 ° C.) containing 0.05% by weight of silica having an average particle size of 4.0 μm and 12.0% by weight of 1,4-cyclohexanedimethanol as a copolymerization component. It is.

(Comparative Examples 1-4)
A laminated polyester film was obtained in the same manner as in Example 1 according to the composition and conditions shown in Table 1. The part which is not mentioned in particular carries out the same method as in Example 1. The characteristics of the obtained laminated polyester film are as shown in Table 1, and the level of peel resistance was not achieved in order to exhibit a desired function.

  The laminated polyester film for building material of the present invention is suitably used as a building material such as wallpaper material, plywood, flooring material or floor heating material, and is useful.

Claims (10)

  For building materials comprising a polyester layer (A layer) composed of polyester a having a melting point of 250 ° C. or lower on one or both sides of a polyester layer (B layer) containing polyester a having a melting point of 250 ° C. or lower. It is a laminated polyester film, the value of the plane orientation coefficient fn measured from the surface side of the layer A is 0.08 or less, and the value of the crystal grain diameter χc of the whole laminated polyester film is 6.0 or more. A laminated polyester film for building materials.   The building material laminate according to claim 1, wherein the polyester a having a melting point of 250 ° C or lower is a copolymerized polyester containing at least one of isophthalic acid and 1,4-cyclohexanedimethanol as a copolymerization component. Polyester film.   3. The polyester a having a melting point of 250 ° C. or less contained in the B layer is 0.1% by weight or more based on the total of the polyesters forming the B layer. 3. Laminated polyester film for building materials.   The laminated polyester film for building materials according to any one of claims 1 to 3, wherein the thickness of the A layer is 50 µm or less.   The laminated polyester film for building materials according to any one of claims 1 to 4, wherein a laminated film layer (C layer) containing polyester is provided on at least one side of the laminated polyester film.   6. The laminated polyester film for building materials according to claim 5, wherein the polyester contained in the C layer is a copolymerized polyester containing isophthalic acid and diethylene glycol as copolymerization components.   7. The laminated polyester film for building materials according to claim 5 or 6, wherein the polyester contained in the C layer is 10 to 60% by weight based on the total amount of resins forming the C layer. The layer C is a coating layer formed of a component that can be applied with an aqueous coating liquid, and is stretched in at least one direction, and the thickness of the coating layer is 0.01 to 2 μm. The laminated polyester film for building materials according to any one of 5 to 7.   Total thickness is 100-500 micrometers, The laminated polyester film for building materials in any one of Claims 1-8 characterized by the above-mentioned.   The laminated polyester film for building materials according to any one of claims 1 to 9, wherein a Ti-based polymerization catalyst is contained in at least one of the A layer and the B layer.