JP4721294B2 - Laminated film and article using the laminated film - Google Patents

Description

  The present invention relates to a laminated film and various articles using the laminated film, and specifically relates to a laminated film in which the durability of a silver layer is improved and an article using the laminated film. .

  Laminated films obtained by laminating various metals on the surface of a plastic film are widely used in various applications. For example, when such a metal is silver, that is, the silver deposited film is used as a reflective film by using the gloss of the silver, or is used as a slit thread (silver thread) obtained by micro slitting a film on which silver is deposited. Has been.

  For example, considering the case where it is used as a reflective film, it is often used as a member of a so-called backlight device. Therefore, this backlight device and a reflective film used therein, that is, a laminated film formed by laminating silver will be described.

  Recently, liquid crystal display devices are used as image display devices for mobile phones, computers, televisions, etc., which can be made much thinner than conventional CRT display devices and can be easily reduced in size. There is an advantage that can be. In particular, it can be said that the demand for the use of this liquid crystal display device is rapidly increasing with the increasing demand for lightness, thinness and miniaturization, which has been noticeable recently.

  Now, in such a liquid crystal display device, a backlight device is usually provided so that the liquid crystal display portion can be clearly seen, but the light emitted from the light source in this backlight device is ultimately efficient. In addition, a mechanism for reaching the liquid crystal display element is required. This is because in the liquid crystal display device, the liquid crystal display portion becomes clearer by illuminating the display portion more strongly from the back.

  For example, in order to allow light rays emitted from a light source in a backlight device using a cold cathode tube as a light source to efficiently reach the liquid crystal display device, the backlight device has a light source for directing all the light rays emitted from the light source to the liquid crystal display device. A light source reflector is installed in a substantially semi-enclosed state. By this light source reflector, the light emitted from the light source is directed in one direction. A light guide plate is installed at the destination of the light beam, and the light beam incident on the light guide plate is emitted toward the liquid crystal plate. However, even in this case, not all light rays are emitted in the same direction, and light rays are emitted in unnecessary directions. That is, the light beam emitted from the light source may be directed directly to the liquid crystal display device, but it is necessary to return the light beam that has fallen from the light guide plate, that is, directed toward the unnecessary direction, to the light guide plate again. For this purpose, a configuration is provided in which a reflection film that reflects the light beam is installed in a position corresponding to an unnecessary direction in which the light beam is emitted, and the light beam that has been emitted in an unnecessary direction is returned to the light guide plate again. The provided backlight device is employed in a liquid crystal display device.

  As described above, in order to effectively use the light reflected from the reflection film in the current liquid crystal display device, the light reflected from the reflection film must correctly reach the liquid crystal display device through the light guide plate. In addition, it can be said that it is desirable that the light reflection performance of the reflective film does not decrease as much as possible due to a change with time. For this purpose, for example, a reflection film as described in Patent Document 1 has been proposed.

JP-A-10-305510

  The reflective film described in Patent Document 1 is a reflective film in which a silver vapor-deposited layer is provided on a plastic film, and by providing a silicon compound resin layer on the front and back of the silver vapor-deposited layer, the silver vapor-deposited layer has durability. It has been granted. By sandwiching the silver layer with the silicon compound resin in this manner, the adsorbed moisture on the surface of the silver deposited layer reacts with the silicon compound resin to be removed, and as a result, durability is imparted to the silver deposited layer.

  However, when actually configured in this way, the adsorbed moisture on the surface of the silver deposited layer reacts with the silicon compound resin to remove the moisture from the surface of the silver deposited layer, thereby preventing the silver deposited layer from being deteriorated by moisture. On the other hand, the silicon compound resin layer that has reacted with the moisture adsorbed on the surface of the silver vapor deposition layer deteriorates from the portion that has reacted with the water, and as a result, the silver vapor deposition layer and the silicon The interlaminar adhesion strength with the compound resin layer rapidly decreases, that is, the phenomenon that the film easily peels off from the portion, resulting in the phenomenon that the performance of the reflective film deteriorates with time. Met.

  The above is the description of the silver deposited film used as the reflective film in the backlight device, but other than the reflective film, for example, even in the case of silver thread obtained by micro slitting the silver deposited film, the interlayer between the silver deposited layer and the undercoat layer In recent years, the same problem has been pointed out in all films formed by depositing silver, such as a problem of peeling due to a decrease in adhesion.

  Therefore, the present invention has been made in view of such problems, and the purpose thereof is that the silver deposited layer does not deteriorate even if time elapses, and the silver deposited layer does not easily peel off. That is, it is to provide a laminated film capable of maintaining the reflection performance for a long period of time and various articles using the laminated film.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention is a metal obtained by laminating a metal and an undercoat layer obtained by laminating a resin on the surface of a polymer resin film serving as a base material. A laminated film formed by laminating a layer and a topcoat layer in this order, wherein the metal is silver, and the resin is one or more of a polyester resin, an acrylic resin, and a urethane resin And a melamine-based resin, wherein the content of the melamine-based resin is 5% by weight or more and 50% by weight or less based on the total amount of the resin .

The invention relating to the transflective film according to claim 2 of the present invention is characterized by using the laminated film according to claim 1 .

The invention relating to the reflective film according to claim 3 of the present invention is characterized by using the laminated film according to claim 1 .

The invention related to the backlight device according to claim 4 of the present invention is characterized in that the laminated film according to claim 1 is used as a reflective film in the backlight device for an image display device.

The invention relating to the slit yarn according to claim 5 of the present invention is characterized in that the laminated film according to claim 1 is microslit.

The invention relating to the glitter according to claim 6 of the present invention is characterized in that the laminated film according to claim 1 is finely pulverized.

  As described above, in the laminated film according to the present invention, since the resin used for the undercoat layer contains a melamine resin, it is possible to prevent the silver deposited layer from corroding while maintaining the interlayer adhesion. become able to. This point will be described in more detail. By making the resin of the undercoat layer a polyester resin, an acrylic resin, or a urethane resin, even if these resins contain a melamine resin, these resins are dried. Since the undercoat layer is formed at such a temperature, the base film is not damaged. In this state, the melamine resin is not completely cured, but nevertheless, the laminated film according to the present invention exhibits the silver corrosion prevention effect by the melamine resin. And in the laminated | multilayer film concerning this invention, the interlayer adhesive force of an undercoat layer and a silver vapor deposition layer is maintained simultaneously. And by using this laminated film for transflective semi-reflective film, reflective film, silver slit yarn, glitter, etc., the silver vapor deposition layer in each member does not deteriorate over time, The obtained effect can be sustained.

  Embodiments of the present invention will be described below. The embodiment shown here is merely an example, and is not necessarily limited to this embodiment.

(Embodiment 1)
A laminated film according to the present invention will be described as a first embodiment.
The reflective film according to the present embodiment comprises an undercoat layer formed by laminating a resin, a metal layer formed by laminating a metal, and a top coat layer on the surface of a polymer resin film serving as a base material. It has the structure formed by laminating in order.
Hereinafter, each part will be described in order, but here, the description will be made assuming that the laminated film according to the present embodiment is used as a reflective film.

  First of all, it is a base film, which may be a commonly used plastic film, for example, a transparent film such as a polyethylene terephthalate (PET) film or the like, as described later. If such a laminated film is used as a reflective film, a white film such as a white PET film may be used in order to improve the reflectance. Further, an olefin film, a polycarbonate (PC) film, a polyethersulfone ( Although a PES) film or the like can be used, a conventionally known PET film is used in this embodiment.

  The thickness of the plastic film as the base material is not particularly limited. For example, the thickness is preferably 20 μm or more and 400 μm or less. However, when the thickness is 400 μm or more, the thickness of the entire reflection film according to the present embodiment is reduced. It is because it becomes impossible to make it thin as necessary, and when it is 20 μm or less, the base film itself is damaged when making the reflective film according to the present embodiment, or the obtained reflective film is easily damaged, This is because a necessary “strain” cannot be obtained for the obtained reflection film itself, and thus a problem such that it becomes too soft to be practically used in actual use tends to occur.

Next, the undercoat layer provided on the surface of the plastic film will be described.
This undercoat layer is provided so that the above-described base film and the metal vapor deposition layer described later are not easily peeled off, but in this embodiment, the metal vapor deposition layer described later is more than that, In particular, the main purpose is to protect a silver deposited layer formed by depositing silver from corrosion caused by moisture, oxygen, or the like.

First, the resin used as a raw material for the undercoat layer will be described.
Conventionally, a melamine resin or a siloxane resin has been used as an undercoat layer in order to protect the silver deposited layer from corrosion, but there has been a problem in using these resins alone. That is, in the case of melamine resin, since the curing temperature is high, when the polymer resin film laminated thereon is exposed to the melamine resin curing temperature, heat wrinkles are generated in the polymer resin film itself, and it should be used as a substrate for the laminated film. Will not be possible. Further, when the siloxane resin was used alone, it absorbed moisture and caused hydrolysis, and eventually the undercoat layer itself with the siloxane resin was damaged, which caused delamination.

  Therefore, in order to solve these problems, the inventor according to the present invention uses a mixed resin obtained by adding a melamine resin to a polyester resin as a resin used for the undercoat layer in the present embodiment.

  First, by using a polyester-based resin, the polymer resin film as a base material, in particular, the adhesiveness with the PET film is improved, and at the same time the adhesiveness with the silver vapor deposition layer is also improved. Adhesiveness between the base film and the silver deposited layer can be ensured. Furthermore, the polyester-based resin is mainly used, and since the drying temperature is low, the heat treatment for completing the undercoat layer does not need to be so high that the base film has a poor appearance, which is preferable. You can do anything. Furthermore, it has the environmental resistance required when the laminated film is used as a reflective sheet, and problems such as a decrease in interlayer adhesion in the aforementioned silicon compound do not occur.

  And the effect by a melamine-type resin can also be exhibited now by making this polyester-type resin contain a melamine-type resin. That is, by using a resin containing a melamine-based resin as an undercoat layer, silver can be prevented from corroding, that is, a product having corrosion resistance can be obtained.

  What should be noted here is that the resin of the undercoat layer is a polyester resin, an acrylic resin, or a urethane resin, and even if these resins contain a melamine resin, the degree to which these resins dries Since the undercoat layer is formed at a temperature of 1, the substrate film is not damaged. In other words, when trying to cure a polyester resin containing melamine resin, an undercoat layer is formed at a temperature at which the polyester resin etc. is cured, but at such a temperature, the melamine resin should not be completely cured, Regardless, the inventors of the present invention have found that the laminated film according to the present invention exhibits the effect of preventing silver corrosion by the melamine resin. In addition, in the laminated | multilayer film concerning this invention, the interlayer adhesive force of an undercoat layer and a silver vapor deposition layer is maintained simultaneously.

  As described above, in this embodiment, the undercoat layer is formed of a resin obtained by mixing a melamine resin with a polyester resin, so that the undercoat layer is formed at the drying temperature of the polyester resin. At the same time, the adhesion between the metal vapor deposition layer, in particular the silver vapor deposition layer and the base film, especially the PET film, is further improved, and the melamine resin is contained in the polyester resin forming the undercoat layer. The undercoat layer can prevent corrosion of the metal deposition layer, particularly the silver deposition layer.

In addition, about the ratio which makes a polyester-type resin contain a melamine-type resin , if it is 5 to 50 weight% with respect to the whole quantity of resin, it is more effective.

  The undercoat layer can be laminated with a resin by a conventionally known method, for example, a so-called wet coating method such as a gravure coating method, a reverse coating method, or a die coating method. In this embodiment, it is formed by a gravure coating method. Further, the thickness is preferably 20 nm or more and 300 nm or less, but this is preferably within such a range when the laminated film according to this embodiment is used as a reflective film, and for other purposes. When using the laminated film concerning this Embodiment, it should just refuse here that it should just be set as the optimal thickness according to each use.

  As described above, in the present embodiment, the polyester resin is mainly used, and the undercoat layer is formed of a resin containing a melamine resin. However, for example, an acrylic resin or a urethane resin is mainly used instead of the polyester resin. It is also possible to do. For these cases, for example, acrylic resins and urethane resins have higher drying temperatures than polyester resins, but not as high as when melamine resins are used alone, In other words, it is not necessary to make the substrate film so hot that it breaks the substrate film. Furthermore, if these resins are used, a metal vapor-deposited layer, particularly a silver vapor-deposited layer, can have good adhesion. Although it is possible to use resin, further detailed explanation is omitted here.

  In the laminated film concerning this Embodiment, the undercoat layer is laminated | stacked on the surface of the base film mentioned above, and also the metal vapor deposition layer is laminated | stacked on the surface. Then, this metal vapor deposition layer is demonstrated easily next.

  The metal vapor deposition layer in the present embodiment is formed by depositing silver in particular, but this is because the explanation is based on the assumption that the laminated film according to the present embodiment is used as a reflection film. This is because silver is most commonly used as the metal vapor deposition layer used in the film.

  The method for laminating the silver vapor deposition layer may be a conventionally known method, for example, a so-called dry coating method such as a vacuum vapor deposition method, a sputtering method, or an ion plating method. In this embodiment, the method is a vacuum vapor deposition method. To do. Moreover, although it can be said that it is suitable if the thickness is 600 mm or more and 1500 mm or less, this is a range that is assumed to be used as a reflective film, that is, when used for the above-mentioned road use and other purposes. It should be noted that the thickness should be effective depending on the purpose.

  In addition, even when the metal vapor deposition layer is made of a metal or a metal compound other than silver, the effect of the above-described undercoat layer can be expected if the vapor deposition layer is mainly composed of silver, but is not necessarily limited to silver. I will add that it is not something to do.

Although not particularly limited, in the present embodiment, a top coat layer is laminated on the surface of the metal vapor deposition layer. For this topcoat layer, the effect of protecting the surface of the metal vapor deposition layer can be expected, but in addition to that, for example, when the topcoat layer is used using the same resin as that used for the undercoat layer described above, It is conceivable to obtain a further effect of preventing corrosion of the silver deposited layer. That is, by adding a melamine resin to the acrylic resin used as the top coat layer, the corrosion resistance of the silver vapor deposition layer can be further effectively improved. In this case, the content of the melamine resin is preferably 5% by weight or more and 50% by weight or less based on the total amount of the resin.

  Note that the topcoat layer in this embodiment may be laminated by the same method as in the case of the undercoat layer, that is, a so-called wet coating method such as a gravure coating method, a reverse coating method, or a die coating method. That's fine. In this embodiment, it is formed by a gravure coating method. Further, the thickness is preferably 0.5 μm or more and 5 μm or less, but this is preferably within such a range when the laminated film according to this embodiment is used as a reflective film, and for other purposes. Therefore, when using the laminated film concerning this Embodiment, it should just refuse here that it should just be set as the optimal thickness according to each use.

  Furthermore, it can be considered to be a top coat layer having scratch resistance for preventing scratches, or to be a top coat layer that also functions as a functional layer having a specific function. Further details will be omitted here.

  Although it is a laminated | multilayer film demonstrated above, it becomes possible to use the laminated | multilayer film obtained by making a metal vapor deposition layer into silver as a reflective film or a semi-transmissive semi-reflective film in which corrosion of silver hardly arises. Further, if the backlight device uses such a reflective film or a semi-transmissive / semi-reflective film, if this backlight device is used as a backlight device of a liquid crystal display device, for example, the performance deteriorates over a long period of time compared to the conventional one. A backlight device that does not occur, that is, can maintain the reflectance in a suitable state over a long period of time can be obtained.

  Furthermore, when the laminated film according to the present embodiment when the metal vapor-deposited layer is a silver vapor-deposited layer is micro-slit to form a silver thread, the silver layer in the slit thread can be made difficult to corrode. Slit yarn that can maintain a long gloss can be obtained, and similarly, the laminated film having the metal deposited layer in the laminated film according to the present embodiment as a silver deposited layer is crushed until it becomes a fine state, and cosmetics, etc. Similarly, when the so-called glitter used in the present invention is used, the silver is hardly corroded, so that it is possible to obtain a glitter that maintains the gloss of silver over a long period of time.

  Laminated films were prepared as follows, and the corrosivity of the silver deposited layer in each laminated film was compared.

  A PET film having a thickness of 38 μm was used as the base film. An undercoat layer was laminated on the surface of the laminated film so as to have a thickness of 50 nm by a gravure coating method. A silver vapor deposition layer was laminated on the surface so as to have a thickness of 1000 mm by a vacuum vapor deposition method. A top coat layer of acrylic resin was laminated on the surface so as to have a thickness of 1 μm by a gravure coating method.

  About the obtained laminated | multilayer film, it investigated as follows about a reflection characteristic, adhesiveness, and an external appearance.

(Reflection characteristics)
Immediately after the laminated film was obtained (initial stage) and after being left in an environment of 60 ° C. and 95% humidity for 250 hours (environmental resistance), each case was examined.
First, the external appearance was judged visually, and at the same time, the total light reflectance was examined with UV3100PC manufactured by Shimadzu Corporation.
(Double-circle): The reflectivity by visual observation was favorable, and the total light reflectance was 92% or more. It was also good from the viewpoint of environmental resistance.
A: The visual reflectivity was good, and the total light reflectance was 92% or more. Moreover, although there was no problem in practical use from the viewpoint of environmental resistance, there was a slight cloudiness that seemed to be due to corrosion on the appearance.
(Triangle | delta): The reflectivity by visual observation was a little good, and the total light reflectance was 92% or less. In addition, from the viewpoint of environmental resistance, clouding that was considered to be due to corrosion was seen to be unsuitable for practical use.
X: The visual reflectivity was poor, and the total light reflectance was 92% or less. In addition, from the viewpoint of environmental resistance, a large amount of cloudiness, which was probably due to corrosion, was observed.

(Adhesion)
Immediately after the laminated film was obtained (initial stage) and after being left in an environment of 60 ° C. and 95% humidity for 250 hours (environmental resistance), each case was examined.
A cross-cut adhesion test was performed for adhesion. That is, 100 squares with a width of 1 mm were made (10 × 10), and a commercially available cellophane tape was attached to the 100 squares, and then the number of squares peeled off was examined by peeling it off.
◎: The number of cells removed is 5 or less ○: The number of cells removed is 6-10
Δ: The number of squares peeled off is 11 to 20
×: Number of squares peeled off is 21 or more

(appearance)
The appearance of the laminated film immediately after it was obtained, mainly the presence or absence of so-called “heat wrinkles”, was visually judged.
◎: Visual appearance is very good ○: Visual appearance is good △: Visual appearance is slightly good ×: Visual appearance is poor The standard was based on whether or not there was, and if so, how much. That is, when no wrinkles were seen, it was “very good”, and when very little was seen, “good”.

  In addition, in the laminated film of each Example and Comparative Example, the mixed resin used as the raw material for the undercoat layer was as follows.

Example 1
1 g of melamine resin was contained in 19 g of polyester resin. The curing temperature of the undercoat layer was 100 ° C.

(Example 2)
5 g of melamine resin was contained in 15 g of polyester resin. The curing temperature of the undercoat layer was 100 ° C.

(Example 3)
10 g of melamine resin was contained in 10 g of polyester resin. The curing temperature of the undercoat layer was 100 ° C.

Example 4
5 g of melamine resin was contained in 10 g of urethane resin. The curing temperature of the undercoat layer was 150 ° C.

(Example 5)
10 g of melamine resin was contained in 10 g of acrylic resin. The curing temperature of the undercoat layer was 150 ° C.

(Comparative Example 1)
Only 20 g of melamine resin was used. The curing temperature of the undercoat layer was 200 ° C.

(Comparative Example 2)
Only 20 g of siloxane-based resin was used. The curing temperature of the undercoat layer was 180 ° C.

(Comparative Example 3)
Only 20 g of polyester resin was used. The curing temperature of the undercoat layer was 100 ° C.

  The results obtained are shown in the table.

As can be seen from this table, when the ratio of the melamine resin contained in the polyester resin, acrylic resin, or urethane resin is 5 % by weight or more and 50% by weight or less with respect to the total amount of the resin , its curing temperature It can be seen that the undercoat layer is formed at the same time as the corrosion of the silver is prevented even if it is not higher than in the case of the melamine resin alone.

Claims (6)

A laminated film in which an undercoat layer obtained by laminating a resin, a metal layer obtained by laminating a metal, and a topcoat layer are laminated in this order on the surface of a polymer resin film serving as a substrate. ,
The metal is silver;
The resin comprises any one or more of a polyester resin, an acrylic resin, or a urethane resin, and a melamine resin,
The content ratio of the melamine resin is 5% by weight or more and 50% by weight or less with respect to the total amount of the resin,
A laminated film characterized by Using the laminated film according to claim 1 ;
A transflective film characterized by the above. Using the laminated film according to claim 1 ;
Reflective film characterized by Using the laminated film according to claim 1 as a reflective film in a backlight device for an image display device,
A backlight device. The laminated film according to claim 1 is microslit,
Characterized by slit yarn. Finely pulverizing the laminated film according to claim 1 ,
Features a glitter.