JPH08230126A - Automotive window bonding laminated polyester film - Google Patents

Abstract

PURPOSE: To obtain a colored film which cannot be manufactured so far by forming an oriented polyester film made of at least three or more layers in such a manner that the inner layer is a layer containing dye and the outermost layer contains no dye and specific condition formulae can be simultaneously satisfied. CONSTITUTION: An automotive window bonding laminated polyester film is an oriented polyester film made of at least three or more layers in such a manner that the outermost layer of a layer for forming exposed two surfaces is a layer containing no dye, and the inner layers except the outermost layer contains dye. The polyester for forming the inner and outermost layers of the film simultaneously satisfies the relations represented by formulae I to III [where IA, IB are the viscosities of the polyester composition for forming the inner and outer layers, dA, dB are the thicknesses (μm) of the inner and outer layers, and TA, TB are visible ray permeability (%) of the inner and outer layers].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated polyester film for attaching to automobile windows.

[0002]

BACKGROUND OF THE INVENTION Polyester films are excellent in heat resistance, water resistance, chemical resistance, mechanical strength, dimensional stability, etc., and have been used for various industrial purposes. Applications are expanding and diversifying. With such diversification, the required characteristics have become more and more severe, but it is the current situation that they have not been sufficiently satisfied.

For example, in applications containing dyes such as automobile window sticking films, X-ray bluing films, and display applications, even if a dye having good color mixture, heat resistance and dispersibility is selected, the dye is sublimated. Due to the property, the inside of the casting roll, the longitudinal stretching roll and the tenter is contaminated during the production of the film, and other brands cannot be produced. Therefore, in reality, the above-mentioned colored film cannot be manufactured, or even if it is manufactured, the cost becomes extremely high.

[0004]

Means for Solving the Problems In view of the above problems, the inventors of the present invention have made earnest studies, and as a result, even if the film contains a dye that is easily sublimated, a film having a specific film structure can be obtained. Found that it is possible to prevent dye sublimation in the manufacturing process of, and as a result, it is possible to obtain a colored film that could not be manufactured until now,
The present invention has been completed.

That is, the gist of the present invention is at least three.
An oriented polyester film consisting of more than one layer, the inner layer is a layer containing a dye, the outermost layer is a layer containing no dye, for automotive window pasting, characterized by simultaneously satisfying the following formula ~ Exists in laminated polyester film.

[0006]

[Number 2] _{0.02 ≦ I B -I A ≦ 0.10} ...... 0.05 ≦ d A / d B ≦ 0.45 ...... 0.05 ≦ T A / T B ≦ 0.60 ......

[In the above formula, I _A is the viscosity of the polyester composition forming the inner layer, I _B is the viscosity of the polyester composition forming the outermost layer, d _A is the thickness of the inner layer (μm), and d _B is the outermost layer. Thickness (μm), T _A represents the visible light transmittance (%) of the inner layer, and T _B represents the visible light transmittance (%) of the outermost layer].

The present invention will be described in detail below. Laminated polyester referred to in the present invention, after stretching all those layers extruded by a co-extrusion method co-extrusion from the die,
It means that it is heat-fixed if necessary. Hereinafter, a film having a three-layer structure will be described as the laminated polyester film. In the present invention, the laminated polyester film is
The polyester film is not limited to the three-layer polyester film as long as the purpose is satisfied, and may be a multilayer having three or more layers.

In the present invention, the polymer constituting each layer of the multilayer film is a polyester obtained by using aromatic dicarboxylic acid or its ester and glycol as main starting materials, and 80% or more of repeating structural units are ethylene terephthalate units. Alternatively, it refers to a polyester having ethylene-2,6-naphthalate units. Then, other third component may be contained as long as it does not deviate from the above range.

As the aromatic dicarboxylic acid component, other than terephthalic acid and 2,6-naphthalenedicarboxylic acid,
For example, isophthalic acid, phthalic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, p-oxyethoxybenzoic acid, etc.) can be used. As the glycol component, other than ethylene glycol, for example, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, or the like may be used alone or in combination.

In the film of the present invention, the outermost layer is a layer constituting two exposed surfaces, and the other layers are called inner layers. The viscosity (IV) of the polyester composition constituting the inner layer and the outermost layer is usually 0.52 to 0.75, preferably 0.
55 to 0.70, more preferably 0.58 to 0.67
Is. When the IV value is less than 0.52, the heat resistance, mechanical strength, etc., which are excellent features of the polyester film when formed into a film, tend to be inferior. The IV value is 0.
When it exceeds 75, the negativeness in the extrusion step during the production of the polyester film tends to be too large, which may reduce the productivity.

[0012] In the present invention, it constitutes the outermost layer of the film.
Viscosity of polyester (I_B ) And the inner layer
Stell's viscosity (I_A) And (I_B-I_A) Is 0.02
˜0.10, preferably 0.03 to 0.08. Or
If the difference is less than 0.02, the coextrusion laminated film described below will be used.
In the process of manufacturing the film, the dye for the outermost layer is included on both ends of the film.
The transparent layer that does not have does not wrap around, and heat treatment process (eg
Dye sublimates from both ends of the inner layer film in the middle tenter)
However, it is not preferable because it will contaminate the tenter.
If the difference exceeds 0.08, the polyester itself
Lost the characteristics of, the inner layer of uniform thickness can not be obtained,
Color unevenness will occur, and the inner and outermost layers will be resistant.
Differences in film properties such as heat resistance and mechanical strength will occur,
It is not preferable because the rum tends to curl.

The film thickness of all layers of the laminated film of the present invention is usually 10 to 50 μm, generally 25 μm.
The ratio (d _A / d _B ) of the layer thickness between the inner layer thickness (d _A ) and the outermost layer thickness (d _B ) of the laminated film of the present invention is 0.05 to
It is 0.45, preferably 0.1 to 0.40. If the ratio is less than 0.05, the dye content must be increased in order to obtain a sufficient light-shielding property, and as a result, the viscosity (IV) of the polyester is excessively reduced and the properties of the polyester itself are lost. It is not preferable because an inner layer having a uniform thickness cannot be obtained and color unevenness occurs. If the ratio exceeds 0.45, the appearance (transparency) of the film will be impaired, which is not preferable.

The visible light transmittance ratio (T _A / T _B ) of the inner layer and the outermost layer of the laminated film of the invention is 0.05 to 0.60,
It is preferably 0.10 to 0.50. Such ratio is 0.
If it is less than 05, the light-shielding property becomes insufficient, which is not preferable. Further, if the ratio exceeds 0.60, it is not preferable because it is difficult to see the outside scenery when it is attached to a window of an automobile, for example.

The dye contained in the inner layer of the laminated film of the present invention is preferably anthraquinone dye, phthalocyanine dye or the like in terms of chemical structure in terms of heat resistance during polyester production and dispersibility in polyester. Disperse dyes and oil-soluble dyes are suitable for dyeing. It is general that these dyes are appropriately selected and used by mixing several types, and the content in the polyester is preferably 0.01 to 10% by weight. The outermost layer of the laminated film of the invention has a roughened surface to improve workability in the winding process during film production and the coating and laminating process during film production for automobile window bonding. It is preferable to impart the property, and for that purpose, fine inert particles may be added.

The fine inert particles used in the present invention preferably have an average particle size of 0.5 to 3.0 μm, more preferably 0.8 to 2.0 μm. If the average particle size is less than 0.5 μm, workability tends to be poor. Also,
If the average particle size exceeds 3.0 μm, the flatness of the film surface may be impaired and the transparency may be impaired. Further, the amount of particles added is preferably in the range of 0.05 to 1.0% by weight, more preferably 0.1 to 0.7% by weight. If the amount of particles added is less than 0.05% by weight, the winding properties tend to be poor. On the other hand, if the amount of particles added exceeds 1.0% by weight, the degree of roughening of the film surface becomes too large, and the transparency may be impaired.

Examples of the inert particles used in the present invention include silicon oxide, titanium oxide, zeolite, silicon nitride, boron nitride, celite, alumina, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate and calcium phosphate. , Lithium phosphate, magnesium phosphate, lithium fluoride, aluminum oxide, silicon oxide, titanium oxide, kaolin, talc, carbon black, silicon nitride, boron nitride and high crosslinking levels as described in JP-B-59-5216. Examples thereof include molecular fine powders, but the present invention is not limited to these. At this time, the inert particles to be blended may be a single component, or two or more components may be used simultaneously.

In the present invention, the method of incorporating the inert particles and the like into the polyester is not particularly limited, but a method of adding the particles to the polymerization step, a method of kneading the particles in advance using an extruder into a master batch, and the like are adopted. However, a particularly preferable method is a method in which particles are directly added and mixed in the extrusion step during the film production step. As the extruder at that time, a twin-screw extruder with a vent is preferable. In order to improve the dispersion of particles, a twin-screw extruder with a different direction is preferable to a twin-screw extruder with a same direction.

The laminated film of the present invention is preferably one in which the extruded film is biaxially stretched and heat-set by a coextrusion method in which all layers are co-melt extruded from a die.
As a co-extrusion method, either a feed block type or a multi-manifold type may be used. The method for producing the laminated film of the present invention will be described more specifically, but the present invention is not particularly limited to the following examples as long as the constituent requirements of the present invention are satisfied.

A polyester containing a predetermined amount of dye (inner layer) and a polyester containing a predetermined amount of inert particles (outermost layer) were supplied to different melt extruders and heated to a temperature above the melting point of the polymer to melt. To do. Then, the molten polymer is bonded and laminated in a laminar flow in the extrusion die and extruded from a slit-shaped die, rapidly cooled and solidified on a rotating cooling drum to a temperature not higher than the glass transition temperature, and substantially amorphous. An unoriented sheet in a state is obtained. In this case, in order to improve the flatness of the sheet, it is preferable to enhance the adhesion between the sheet and the rotary cooling drum. In the present invention, the electrostatic application adhesion method and / or the liquid coating adhesion method is preferably adopted.

The electrostatic application adhesion method is usually a method in which a linear electrode is placed on the upper surface side of the sheet in a direction orthogonal to the flow of the sheet, and a DC voltage of about 5 to 10 kV is applied to the electrode to statically apply the sheet. This is a method of applying an electric charge to improve the adhesion to the drum. In addition, the liquid application contact method is a method for improving the adhesion between the drum and the sheet by uniformly applying the liquid to the whole or part of the surface of the rotary cooling drum (for example, only the portions that contact both ends of the sheet). Is. In the present invention, both may be used together if necessary.

In the present invention, the sheet thus obtained is biaxially stretched to form a film. Specifically, the unstretched sheet is stretched in the longitudinal direction at 70 to 145 ° C. to 2 to 6 times in the longitudinal direction to obtain a longitudinally uniaxially stretched film, and the coating liquid is sequentially applied to both surfaces of the film. , Moderate drying, or undried, stretched in the transverse direction at 90 to 160 ° C. by 2 to 6 times, and 150 to
It is preferable to perform heat treatment at 250 ° C. for 1 to 600 seconds. Further, in this case, a method of relaxing 0.1 to 20% in the longitudinal direction and / or the transverse direction in the maximum temperature zone of the heat treatment and / or the cooling zone at the exit of the heat treatment is preferable. Further, it is also possible to add re-longitudinal stretching and re-transverse stretching if necessary.

When the laminated film of the present invention is processed into a film for sticking to automobile windows, it is necessary to improve properties required according to the properties required, such as adhesiveness, antistatic property, weather resistance and surface hardness. After completion of the longitudinal stretching, a so-called in-line coating may be carried out in which coating is performed before the entrance of the tenter for transverse stretching and drying is performed in the tenter. In addition, various coatings may be performed by offline coating after the production of the laminated film. Such a coat may be either single-sided or double-sided. The coating material may be either water-based and / or solvent-based in the case of off-line coating, but is preferably water-based or water-dispersed in the case of in-line coating.

[0024]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples unless it exceeds the gist thereof. The physical property measuring methods used in the present invention are shown below. (1) Viscosity (IV) 1 g of the polymer is mixed with phenol / tetrachloroethane = 1 /
It was dissolved in 100 ml of a mixed solvent of 1 (weight ratio) and measured at 30 ° C. (2) Lamination Thickness of Film (d _A , d _B ) After fixing and molding a small piece of film with an epoxy resin, it was cut with a microtome and the cross section of the film was observed with a transmission electron microscope photograph. Of the cross section, two parallel to the film surface, the interface is observed by light and dark. The distance between the two interfaces and the film surface was measured from 10 photographs, and the average value was taken as the laminate thickness.

(3) Visible Light Transmittance (T _A , T _B ) _A monolayer film having the same thickness as the laminated film was prepared, and JI
It measured according to S-A5759. (4) Average particle size Centrifugal sedimentation type particle size distribution analyzer SA- manufactured by Shimadzu Corporation
The particle size was measured by a sedimentation method based on Stokes's resistance law using CP3 type. The value of 50% integrated (volume basis) in the equivalent spherical distribution of the particles obtained by the measurement was used as the average particle diameter.

The method for producing the polyester raw materials used in the following examples and comparative examples is as follows. << Production of Polyester-A >> Dimethyl terephthalate 10
Using 0 parts by weight and 60 parts of ethylene glycol as a starting material, 0.09 parts by weight of magnesium acetate tetrahydrate as a catalyst was placed in a reactor, the reaction starting temperature was set to 150 ° C., and the reaction temperature was gradually increased with the distillation of methanol. The temperature was raised to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was substantially completed. To this reaction mixture, 0.04 part of ethyl acid phosphate and 0.04 part of antimony trioxide were added, and a polycondensation reaction was carried out for 4 hours. That is, the temperature is 2
The temperature was gradually raised from 30 ° C to 280 ° C. On the other hand, the pressure was gradually reduced from atmospheric pressure, and finally set to 0.3 mmHg. After 4 hours from the start of the reaction, the reaction was stopped and the polymer was discharged under nitrogen pressure. The viscosity of the obtained polyester was 0.65.

<< Polyester-B and Polyester-
Production of B1 >> Polyester-B was obtained in the same manner as in the production of polyester-A except that the polycondensation reaction was carried out for 3 hours and 15 minutes. The viscosity of the obtained polyester was 0.53. Polyester-B 2
Solid phase polymerization was carried out at 25 ° C. for 15 hours under the condition of 0.3 mmHg. The viscosity of the obtained polyester-B1 is 0.78.
Met.

<< Production of Polyester-C >> Polyester-A is produced in the same manner as polyester-A except that after the transesterification, 0.1 part by weight of silica particles having an average particle diameter of 2.31 μm is used. -C was obtained. The viscosity of the obtained polyester was 0.66.

<< Production of Polyester-D >> After drying 100 parts by weight of polyester-A, 0.7 parts by weight of DIARESIN RED HS manufactured by Mitsubishi Chemical Co., Ltd. and H3G of the same blue
0.8 parts by weight and 0.4 parts by weight of Yellow F were extruded with a vent type twin-screw extruder to obtain polyester-D. The viscosity of the obtained polyester was 0.61.

<< Production of Polyester-E >> After drying 100 parts by weight of polyester-A, 1.4 parts by weight of DIARESIN RED HS manufactured by Mitsubishi Chemical Co., Ltd. and Blue H3G of the same.
1.6 parts by weight and 0.8 parts by weight of Yellow F were extruded with a vent type twin-screw extruder to obtain polyester-E. The viscosity of the obtained polyester was 0.60.

<< Polyester-F and Polyester-
Production of F1 >> In the production of polyester-D, polyester-B is used instead of 100 parts by weight of polyester-A.
Polyester-F was obtained in the same manner as Polyester-D except that the amount was 100 parts by weight. The viscosity of the obtained polyester was 0.51. Similarly polyester-A
Polyester-F1 was obtained in the same manner as polyester-D except that 100 parts by weight of polyester-B1 was used instead of 100 parts by weight. The viscosity of the obtained polyester was 0.76.

<Production of Polyester-G> After drying 100 parts by weight of polyester-A, 0.1 part by weight of DIARESIN RED HS manufactured by Mitsubishi Chemical Co., Ltd., and H3G of the same blue H3 G
0.15 parts by weight and 0.05 parts by weight of Yellow F were extruded with a vent type twin-screw extruder to obtain polyester-D. The viscosity of the obtained polyester was 0.64.

Example 1 Polyester-C was dried at 180 ° C. for 4 hours and then dried at 285 ° C.
In the main extruder set to No. 28 polyester-D
It was fed into a sub extruder set at 5 ° C. Here, the sub-extruder used a twin-screw extruder with different directions, and the main extruder used a normal single extruder. After the polymer of the main extruder is branched into two layers (outermost layer) on the front and back of the film, the polymer from the sub-extruder is merged with the feed block via a gear pump and a filter and extruded into a sheet, and the surface temperature is raised to 30 ° C. Using the electrostatic cooling method to cool and solidify by the set rotary cooling drum, thickness 360μm
A substantially amorphous sheet of was obtained. The obtained amorphous sheet was stretched in the longitudinal direction at a temperature of 83 ° C. by a factor of 3.6, and then heat-treated at 230 ° C. for 10 seconds while being relaxed by 2% in the width direction.
A biaxially oriented film having a thickness of 0.5 μm / 4 μm / 10.5 μm and a total layer thickness of 25 μm was produced.

Example 2 A biaxially stretched film was produced in the same manner as in Example 1 except that polyester-E was used instead of polyester-D.

Comparative Example 1 A biaxially stretched film was produced in the same manner as in Example 1 except that polyester-F was used instead of polyester-D. Since the obtained film had a low intrinsic viscosity in the inner layer, the inner layer had a non-uniform thickness and could not be used as a film for sticking to automobile windows.

Comparative Example 2 A biaxially stretched film was produced in the same manner as in Example 1 except that polyester-F1 was used instead of polyester-D.

Comparative Example 3 A biaxially stretched film was produced in the same manner as in Example 2 except that the laminated polyester film had a thickness composition ratio of 9 μm / 7 μm / 9 μm. Comparative Example 4 A biaxially stretched film was produced in the same manner as in Example 1 except that polyester-G was used instead of polyester-D.

Comparative Example 5 A biaxially stretched film was produced in the same manner as in Example 2 except that the thickness composition ratio of the laminated polyester film was changed to 12.3 μm / 0.4 μm / 12.3 μm. The properties of the obtained laminated polyester film are summarized in Table 1 below.

[0039]

[Table 1]

[0040]

INDUSTRIAL APPLICABILITY The film of the present invention is a colored film which could not be produced until now, and the industrial value of the present invention is high.

Claims (1)

[Claims] 1. An oriented polyester film comprising at least three or more layers, wherein the inner layer is a layer containing a dye and the outermost layer is a layer containing no dye. Characteristic laminated polyester film for automobile windows. [Number 1] _{0.02 ≦ I B -I A ≦ 0.10} ...... 0.05 ≦ d A / d B ≦ 0.45 ...... 0.05 ≦ T A / T B ≦ 0.60 ...... [ In the above formula, I _A is the viscosity of the polyester composition forming the inner layer, I _B is the viscosity of the polyester composition forming the outermost layer, d _A is the thickness of the inner layer (μm), and d _B is the thickness of the outermost layer (μm). ), T _A represents the visible light transmittance (%) of the inner layer, and T _B represents the visible light transmittance (%) of the outermost layer].