JP5039644B2 - Laminated film - Google Patents

Description

  The present invention relates to a laminated film, and specifically, a laminated film excellent in environmental resistance while ensuring interlayer adhesion between a base film and a layer imparting a specific function laminated on the surface thereof. The present invention relates to a laminated film comprising an undercoat layer that can be formed into a film.

  Laminated films obtained by laminating various metals, metal oxides, metal nitrides, and the like on the surface of plastic films to give specific functions to plastic films are widely used in various applications.

  For example, when the metal is silver or aluminum, that is, the silver vapor-deposited film / aluminum vapor-deposited film is used as a reflection film by using its gloss, and further used, for example, in a backlight device of a liquid crystal display device.

  Further, when silicon oxide is laminated, the gas barrier property can be imparted to the plastic film due to the property of silicon oxide, so that the property deteriorates when it comes into contact with oxygen or water vapor, such as food and electronic machinery. This is widely used as a packaging material for parts and the like.

  Further, when a tin-indium oxide (hereinafter also referred to as “ITO”) is laminated, it can be used as a conductive film utilizing the conductivity of ITO. For example, it is widely used as a transparent electrode member such as a touch panel.

  As described above, in order to laminate various metals and the like on the surface of a plastic film, a group of methods called a so-called dry coating method, for example, a vacuum deposition method, a sputtering method, and the like are performed.

  On the other hand, if the metal is simply laminated on the surface of the plastic film, the laminated metal easily peels off and drops, and even if it is a laminated film with a specific function, its function is long. It will not be demonstrated stably over a period of time.

  Therefore, a layer called an undercoat layer is generally provided in advance on the surface of a plastic film on which metal or the like is to be laminated. The undercoat layer is, in a very simple way, present between the plastic film and the layer laminated on the surface thereof to increase their adhesion, in other words, the laminated layer is a plastic film. It can be said that it produces the action of tying it so as not to peel off.

  To further explain this point, there is also a phenomenon that the laminate is easy to peel off if a laminated film formed by laminating metal or the like is simply left to give a specific function to the surface of the plastic film. However, in reality, a situation where it is easy to peel off depending on the usage situation appears. For example, in the case of the above-described example, in the reflective film used in the backlight device, the heat generated by the backlight expands the plastic film and the laminate as the base material. Therefore, a situation occurs in which the laminate is easily peeled off. Similarly, in the case of a gas barrier film, a physical force is applied from the outside when performing a packaging operation or depending on a situation such as transport after packaging, and as a result, a situation where the laminate is easily peeled occurs. Furthermore, if it is used for a touch panel, the effects of heat dissipation from the device and the effects of physical external force applied by operating the touch panel are combined, and no special measures have been taken. A situation in which the laminate easily peels off is likely to occur.

  Therefore, in order to prevent the phenomenon that the laminate described above easily peels, an invention has been proposed in which the anchor coat layer is devised so as not to peel off.

  For example, Patent Document 1 discloses an invention relating to a film including a base polymer film / undercoat layer / transparent conductive thin film, wherein the undercoat layer includes a compound having at least one of an amino group and a phosphate group. Are listed. Patent Document 2 describes an invention relating to a transparent conductive film formed by laminating a transparent thin film layer made of a metal oxynitride at a transparent plastic film / transparent conductive layer interface.

JP 2003-115220 A Japanese Patent Laid-Open No. 11-48388

  If it is the film described in this patent document 1, since it was set as the structure containing the compound which has at least 1 sort (s) among an amino group and a phosphate group in an undercoat layer, the adhesiveness of an undercoat layer and a transparent conductive thin film is improved. It is said that a touch panel with excellent durability can be obtained by avoiding peeling and missing of the transparent conductive thin film.

  However, when a general environmental resistance test required for the touch panel application was performed on this film, the adhesion between the undercoat layer and the transparent conductive thin film after the test became insufficient, and the electrical properties of the transparent conductive thin film were further reduced. It was found that the rate of change in resistance would be high. In other words, if it is this film, it seems that it will exhibit suitable performance immediately after it is manufactured, but if it is actually used for a long time as a transparent electrode such as a touch panel, the transparent conductive thin film is peeled off. Therefore, it cannot be said that it is suitable after all.

  Moreover, if it is a transparent conductive film described in patent document 2, since this has especially favorable adhesive force with an organic substance by providing a metal oxynitride thin film layer, it is in the interface of a transparent conductive layer and a plastic film. It is said that if it exists, adhesion will be improved.

  However, in order to provide this metal oxynitride thin film layer, it is necessary to use a so-called dry coating method such as a vacuum deposition method or an ion plating method. Therefore, the production cost is likely to be high, and the possibility that the productivity itself is low is very high. Furthermore, by providing a metal oxynitride thin film layer, it is considered that the resulting transparent conductive film has insufficient flexibility. For example, when this is used for a touch panel, it is considered that there is a high possibility that it will be easily damaged if it is used for a long time because of insufficient flexibility. It cannot be said.

  Therefore, the present invention has been made in view of such problems, and the purpose thereof is to devise a so-called undercoat layer to ensure interlayer adhesion over a long period of time and at the same time carry out an environmental resistance test. Is to provide a laminated film in which performance deterioration after the test does not occur.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention includes at least an undercoat layer and a specific functional layer imparting a specific function on the surface of a polymer resin film serving as a substrate. It is a laminated film formed by laminating sequentially, and the main material for forming the undercoat layer is a silane coupling agent containing a hydrolyzable group and an organic functional group , which is a monomer type silane coupling agent and ethanol And an oligomer type silane coupling agent obtained by mixing an acetic acid aqueous solution .

  Invention of Claim 2 of this invention is a laminated | multilayer film of Claim 1, Comprising: The said organic functional group is any one or more of an amino group, an epoxy group, or an acryl group, It is characterized by the above-mentioned. And

  Invention of Claim 3 of this invention is a laminated | multilayer film of Claim 1 or Claim 2, Comprising: The said specific function layer is based on either or more of a metal, a metal oxide, or a metal nitride. It is characterized by.

  Invention of Claim 4 of this invention is a laminated film of Claim 1 thru | or 3, Comprising: The said specific function layer is a layer by a transparent conductive substance, It is characterized by the above-mentioned.

The invention according to claim 5 of the present invention is the laminated film according to claim 4 , wherein the transparent conductive material is any of zinc oxide, tin-indium oxide, silicon oxynitride, or indium oxynitride. Or a plurality thereof.

  Invention of Claim 6 of this invention is a laminated | multilayer film of Claim 1 thru | or 3, Comprising: The said specific function layer is a layer which has gas barrier property, It is characterized by the above-mentioned.

  The invention according to claim 7 of the present invention is the laminated film according to claim 6, wherein the specific functional layer is one or more of oxide or nitride of silicon or aluminum, It is characterized by.

  The invention according to claim 8 of the present invention is the laminated film according to claim 1 or 3, wherein the specific functional layer is either or both of aluminum and silver. .

As described above, if it is a laminated film according to the present invention, as a main material for forming the undercoat layer, it contains a hydrolyzable group and an organic functional group , a monomer type silane coupling agent, ethanol and an acetic acid aqueous solution, As the main material is an oligomer-type silane coupling agent obtained by mixing, it is possible to maintain good adhesion between the polymer resin film and the specific functional layer located on both sides Easy to do. In addition, by using an undercoat layer having such characteristics, when heating is performed in an ordinary so-called vapor-deposited film, the laminate easily peels off due to the difference in thermal expansion coefficient between the base film and the laminate. However, in the case of the laminated film according to the present application, even when heat is applied, since the undercoat layer has a flexibility that can absorb and reduce the thermal expansion of the polymer film to some extent, The expansion of the molecular film is not directly transmitted to the laminate, so that the laminate is not peeled off due to the thermal expansion of the polymer film, and as a result, it is possible to easily obtain a laminated film that can exhibit stable performance over a long period of time. I can do it.

  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 laminated film according to the first embodiment has a configuration in which at least an undercoat layer and a specific functional layer imparting a specific function are laminated in this order on the surface of a polymer resin film serving as a base material. Have. Hereinafter, the specific functional layer is made of one or more of metal, metal oxide, or metal nitride, and the specific functional layer is a layer made of a transparent conductive material, that is, the lamination according to the present embodiment. The film will be described as a transparent conductive 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 does not easily peel off the base film described above and the vapor deposition layer described later, protects the vapor deposition layer described later from corrosion due to moisture, oxygen, etc., and further to this embodiment. It is provided mainly for the purpose of preventing the vapor deposition layer from peeling and dropping due to the difference in thermal expansion coefficient between the base film and the vapor deposition layer when the transparent conductive film is heated. Of course, the undercoat in this embodiment also has other purposes, but these will be described later and are omitted here.

The main material of the undercoat layer will be described.
Conventionally, for example, an organosilicon compound has been used as the undercoat layer, but in this embodiment, a silane coupling agent containing a hydrolyzable group and an organic functional group is used as a main material. By containing a hydrolyzable group, it becomes an undercoat layer that is easy to bond with the inorganic component constituting the laminate in the present embodiment, that is, the transparent conductive layer, and by containing an organic functional group, the plastic in the present embodiment The undercoat layer can easily interact with the film.

  In particular, the organic functional group is preferably any one or more of an amino group, an epoxy group, and an acrylic group in order to improve the adhesion with a plastic film as a base material. Furthermore, since the thermal expansion coefficient of the transparent conductive layer due to the inorganic component laminated thereon is generally lower than the thermal expansion coefficient of the base film during heating, the undercoat layer in the present embodiment It can be said that those having the flexibility to relieve the thermal expansion of the base film are more suitable. That is, when the laminated film according to the present embodiment is heated, if the difference between the thermal expansion coefficient of the base film and the thermal expansion coefficient of the laminate is large, the laminate cannot follow the thermal expansion of the base film, The adhesion between the two deteriorates and the laminate peels off over time, but there is heat between the base film and the laminate. If a layer having an expansion coefficient, that is, the undercoat layer in the present embodiment is laminated, even if the base film is heated and expanded, there is no significant difference from the thermal expansion coefficient of the undercoat layer. Since there is no significant difference between the thermal expansion coefficient of the undercoat layer and the laminate, that is, the thermal expansion coefficient of the transparent conductive layer, the undercoat layer is laminated even when the undercoat layer is thermally expanded. The transparent conductive layer does not follow Is released, it can prevent the phenomenon occurs that.

  As a result of various studies by the inventors, it has been found that an oligomer type acrylic silane coupling agent is particularly suitable. In this embodiment, an oligomer type acrylic silane coupling agent also containing a hydrolyzable group is used. Was used as the main material of the undercoat layer.

  Specifically, a monomer type acrylic silane coupling agent was mixed with ethanol and an aqueous solution adjusted in pH by an acetic acid aqueous solution to obtain an oligomer type acrylic silane coupling agent containing a hydrolyzable group.

  This is laminated | stacked on the surface of PET film used as the above-mentioned base film. The method of stacking is not particularly limited and may be a conventionally known method, but in the present embodiment, it is as follows. That is, the undercoat layer was laminated | stacked by apply | coating the above-mentioned silane coupling agent to the surface of PET film by the bar coater method. The thickness is preferably 10 nm or more and 300 nm or less, and more preferably 15 nm or more and 200 nm or less in order to effectively achieve the above-described purpose of relaxing the thermal expansion of the base film.

  Although not described in detail here, in order to further improve the adhesion between the undercoat layer and the base film, plasma treatment, corona treatment, or solvent cleaning is performed on the surface of the base film prior to laminating the undercoat layer. However, here, these treatments are not particularly performed, and an undercoat layer is laminated on the PET film surface by a bar coater method.

  When the undercoat layer is laminated on the surface of the base film as described above in the laminated film according to the present embodiment, that is, the transparent conductive film, a transparent conductive layer having transparent conductivity is further laminated on the surface. The transparent conductive layer may be made of one or more of metal, metal oxide, and metal nitride, and more specifically zinc oxide, tin-indium oxide, silicon oxynitride, or acid It may be any one or a plurality of indium nitrides. Of course, it is not limited to a specific substance as long as it is possible to obtain a transparent conductive layer by laminating a substance having transparent conductivity even if it is not described here. In this embodiment, AZO (zinc oxide doped with aluminum) is stacked as a transparent conductive layer.

  The AZO stacking method may be a conventionally known method, for example, a layered by a so-called dry coating method such as a vacuum deposition method or a sputtering method. In the present embodiment, this is laminated by a conventionally known method and procedure by a sputtering method.

  Thus, according to the present embodiment, the PET film / the transparent conductive layer having the constitution of the undercoat layer by the acrylic acrylic silane coupling agent containing the hydrolyzing group / the transparent conductive layer by AZO. A film is obtained. As described above, the procedure for laminating these layers is not a special technique and is laminated by a conventionally known technique. And the obtained transparent conductive film is formed by laminating an undercoat layer with an oligomer type acrylic silane coupling agent containing a hydrolyzable group, for example, by using this as a transparent electrode of a touch panel for a long time. Even if heat is applied, the transparent conductive layer does not peel off, and the function can be maintained for a long period of time.

  In the silane coupling agent, the hydrolyzable group acts to improve the adhesion to the transparent conductive layer and the acrylic group to the PET film, respectively, and stabilizes the state of adhesion by them. Even when exposed to the environment, the interlayer adhesion is maintained without deterioration, so that the function can be maintained over a long period as a whole.

  Furthermore, by laminating the above undercoat layer, the PET film, the undercoat layer, the transparent conductive layer, and the respective thermal expansion coefficients are in the order of the PET film, the undercoat layer, and the transparent conductive layer. Even if the PET film suddenly expands due to heating, the undercoat layer can follow it, and the transparent conductive layer can sufficiently follow the expansion of the undercoat layer. Therefore, it can be said that delamination does not occur in this respect as well.

(Embodiment 2)
Next, unlike the embodiment described above, a laminated film according to the present invention in which the specific functional layer is a gas barrier layer having gas barrier properties, that is, a gas barrier film will be described as a second embodiment.

Note that description of matters similar to those in the first embodiment is omitted.
First, the basic configuration of the gas barrier film according to the present embodiment is the same, that is, base film / undercoat layer / gas barrier layer.

  Similarly, the base film uses a PET film as an undercoat layer, and an oligomer type acrylic silane coupling agent containing a hydrolyzable group is used as in the previous embodiment. It is refused beforehand that it is not limited.

  Now, although it is a gas barrier layer, the material used for this may be a conventionally known material such as silicon oxide, for example, an oxide or nitride of silicon or aluminum, or a material using a plurality of these, In this embodiment mode, the layer is made of silicon oxide.

  This silicon oxide is also a metal oxide and easily binds to a hydrolyzable group contained in the undercoat layer according to the present embodiment. That is, even when silicon oxide is used, it can be said that the adhesion to the undercoat layer is still good.

  The method for laminating silicon oxide is not particularly limited, and may be a conventionally known method. Further, the thickness is not particularly limited, and there is no problem as long as the gas barrier property equivalent to the conventional one can be exhibited.

  Thus, even when the laminated film according to the present invention is a gas barrier film. The relationship between the base film and the undercoat layer, the undercoat layer and the silicon oxide, that is, the metal oxide, is the same as that described in the previous embodiment, so that the performance can be maintained for a long time from the viewpoint of environmental resistance. A gas barrier film can be easily obtained.

(Embodiment 3)
As another embodiment, the case where the specific functional layer is a layer capable of exhibiting a metallic luster, that is, a laminated film according to the present invention, that is, a metallic luster layer, that is, a reflective film will be described.

  As this reflective film, silver or aluminum is usually laminated on the surface of the base film / undercoat layer in many cases. In this embodiment, silver is laminated. The base film and the undercoat layer are the same as described above.

  Even when the metal itself is laminated in this manner, the hydrolysis group contained in the undercoat layer is also likely to be bonded, and as a result, similarly to the two embodiments described above, the interlayer adhesion is also performed. A relationship such as force is established. That is, the same relationship also works between the undercoat layer and the silver layer deposited on the surface, and as a result, delamination does not occur even when exposed to heat or humidity for a long time. A reflective film that can maintain the force over a long period of time can be obtained.

  Laminated films were prepared as follows, and an environmental resistance test was performed on each laminated film.

  A PET film having a thickness of 188 μm was used as the base film. A coating solution having the composition shown in Table 1 was applied to the surface of the laminated film with a bar coater, and then dried at 150 ° C. for 1 minute to laminate an undercoat layer having a dry film thickness of 20 nm. Thereafter, AZO was set as a target of a magnetron DC sputtering apparatus, and a laminate in which the undercoat layer was formed was set in a vacuum chamber. And after exhausting the inside of a chamber to 1 * 10 <-3> Pa, argon gas was introduce | transduced in the chamber on the conditions of 60 cc / min, and it adjusted so that it might be set to 0.2 Pa. A voltage was applied to the AZO target, and an AZO layer having a thickness of 140 nm was laminated on the undercoat layer.

  The following test was performed as an environmental resistance test on the obtained laminated film.

1) Heat resistance test The laminated film was left in a 90 ° C dryer for 250 hours.
The rate of change in electrical resistance and the adhesiveness of the laminated film before and after standing were measured.
The adhesion was measured by a method according to the standard of JIS K 5400.

2) Moisture and heat resistance test The laminated film was allowed to stand for 250 hours in a high-temperature and high-humidity bath at 60 ° C and 95% humidity.
The rate of change in electrical resistance and the adhesiveness of the laminated film before and after standing were measured.
The adhesion was measured by a method according to the standard of JIS K 5400.
For each of the above tests, the case where the rate of change of the electrical resistance value was less than 20% was judged good, and the case where it changed by 20% or more was judged as defective.

The materials used for the undercoat layer were as follows.
(Examples 1-3)
A monomer type silane coupling agent and an aqueous solution adjusted in pH with ethanol and an acetic acid aqueous solution were mixed and stirred using a magnetic stirrer to obtain an oligomer type silane coupling agent. As the silane coupling agent, an acrylic silane coupling agent, an amino silane coupling agent, and an epoxy silane coupling agent were used.

(Comparative Examples 1-3)
A monomer type silane coupling agent was used as an undercoat layer as it was.

The obtained results are shown in the table.

  As can be seen from this table, if the laminated film according to the present invention, there is no problem of deterioration of electrical properties and adhesion after the environmental resistance test, that is, a laminated film having excellent environmental resistance. You can see that

Claims (8)

A laminated film formed by laminating at least an undercoat layer and a specific functional layer imparting a specific function in this order on the surface of a polymer resin film to be a base material,
The main material for forming the undercoat layer is a silane coupling agent containing a hydrolyzable group and an organic functional group, and an oligomer obtained by mixing a monomer type silane coupling agent with ethanol and an aqueous acetic acid solution A type of silane coupling agent ,
A laminated film characterized by The laminated film according to claim 1,
The organic functional group is any one or more of an amino group, an epoxy group, and an acrylic group;
A laminated film characterized by The laminated film according to claim 1 or 2,
The specific functional layer is made of one or more of metal, metal oxide, and metal nitride,
A laminated film characterized by The laminated film according to claim 1, wherein:
The specific functional layer is a layer made of a transparent conductive material;
A laminated film characterized by The laminated film according to claim 4 ,
The transparent conductive material is any one or more of zinc oxide, tin-indium oxide, silicon oxynitride, or indium oxynitride,
A laminated film characterized by The laminated film according to claim 1, wherein:
The specific functional layer is a layer having gas barrier properties;
A laminated film characterized by The laminated film according to claim 6,
The specific functional layer is any one or a plurality of oxides or nitrides of silicon or aluminum;
A laminated film characterized by The laminated film according to claim 1 or 3, wherein
The specific functional layer is aluminum or silver or both,
A laminated film characterized by