JP6798136B2 - Manufacturing method of joint structure - Google Patents

Description

The present invention relates to a method of manufacturing a joined structure.

Conventionally, polarizing plates used in liquid crystal displays and the like have been manufactured by, for example, attaching a protective film made of a transparent resin to one side or both sides of a polarizing element made of a resin film with an adhesive.
In recent years, in order to reduce costs and improve the flexibility of displays, it has been required to make the polarizing plate thinner. For example, a method of manufacturing by laminating a polarizer and a protective film without using an adhesive has been proposed. Has been done.

For example, in Patent Document 1, a polarizing plate is manufactured by subjecting a bonding surface of a protective film to a surface treatment such as a corona treatment, and then laminating a polarizer and a protective film and performing a treatment such as heating. How to do it is described. The polarizer is made of, for example, a polyvinyl alcohol-based resin. Since the polyvinyl alcohol-based resin contains an OH group in its chemical structure, the polarizer exhibits hydrophilicity. On the other hand, in the protective film, OH groups and COOH groups, which are hydrophilic functional groups, are formed on the surface of the protective film by surface treatment. Therefore, it is considered that the principle of bonding is that the functional groups are bonded to each other or by hydrogen bonds generated via water adsorbed on the functional groups.

However, when the surface treatment of the polarizer is not performed, sufficient bonding strength may not be obtained due to the presence of fine organic substances in the atmosphere adhering to the surface of the polarizer.
In response to such a problem, for example, in Patent Document 2, not only the surface to be the bonding surface of the protective film but also the surface to be the bonding surface of the polarizer is subjected to surface treatment to obtain the polarizer. It is described to improve the wettability of the surface. Further, it is described that a thin film of water is formed by steam gas and a silane coupling agent is used in combination in order to increase the bonding strength.

Japanese Unexamined Patent Publication No. 2008-122502 Japanese Patent No. 567087

However, when each of the protective film and the polarizer is surface-treated and bonded to each other, sufficient bonding strength can be obtained immediately after bonding, but the bonding strength decreases over time, and the problem is that the bonding is easily peeled off. It became clear that
The cause of such a problem is presumed as follows. It is known that the surface treatment (hydrophilization treatment) can be performed by, for example, corona treatment, plasma treatment, ozone treatment, or ultraviolet irradiation treatment. By surface treatment, the molecular structure of the polyvinyl alcohol-based resin constituting the polarizer is cut and oxidized to form hydrophilic functional groups such as OH group and COOH group. As a result, the surface of the polarizer becomes hydrophilic. Further, on the surface of the polarizer, an organic substance (surface treatment product) composed of a low molecular weight compound having an OH group derived from a polyvinyl alcohol-based resin is generated. Since this surface treatment product contains OH groups, it acts like an adhesive by hydrogen bonding. Therefore, sufficient bonding strength can be obtained immediately after bonding.
However, it was found that the organic matter produced was altered over time to a state in which the OH group was lost. After a predetermined time has elapsed from joining the treated surfaces of the PVA resin film and the cycloolefin resin film, which have been surface-modified by vacuum ultraviolet light irradiation, the cycloolefin resin is actually used. It was confirmed that the film was easily peeled off. When the present inventor examined the surface (bonding surface) of the PVA resin film from which the cycloolefin resin film was peeled off by X-ray photoelectron analysis (XPS), as shown in the curve (b) in FIG. 10, it was untreated. It was confirmed that the peak (CO) derived from the OH group, which was present in the X-ray photoelectron spectrum (curve (a)) of the PVA resin film, has disappeared.
As described above, since the organic substance generated on the surface of the polarizer by the surface treatment has an OH group, it will be bonded to the hydrophilic functional group on the surface of the surface-treated protective film. However, in the state where the OH groups in the organic substance are bonded, it is considered that the organic substance is denatured with the passage of time, so that the hydrogen bond is lost and the bonding strength is lowered.

The present invention has been made based on the above circumstances, and manufactures a bonded structure capable of obtaining a strong bonded state and avoiding a decrease in bonding strength over time. It is an object of the present invention to provide a method and an apparatus for manufacturing a bonded structure.

The method for producing a bonded structure of the present invention is a method for producing a bonded structure formed by joining a second bonded material to a first bonded material.
A surface modification treatment step for improving the wettability of the surface to be the joint surface of one or more of the first joint material and the second joint material, and
An organic substance removal treatment step of heating and removing the organic matter generated on the joint surface that has been surface-modified in the surface modification treatment step so that the organic substance is removed .
It is characterized by including a joining treatment step of laminating and joining the first joining material and the second joining material so that the surfaces to be the respective joining surfaces are in close contact with each other.

In the method for producing a bonded structure of the present invention, the bonding material subjected to the surface modification treatment in the surface modification treatment step is the first bonding material, and the first bonding material is used in the chemical structure. It is preferable to use a resin having an OH group. Specifically, it is preferable to use a material made of a polyvinyl alcohol-based resin as the first bonding material.
Further, as the second bonding material, it is preferable to use a resin made of a resin different from that of the first bonding material.

Furthermore, in the method for producing a bonded structure of the present invention, in the surface modification treatment step, vacuum ultraviolet light is applied to the surface of one or more of the first bonded material and the second bonded material. By irradiating, or by performing any of corona treatment, plasma treatment, and ozone treatment on the surface of one or more joint surfaces of the first joint material and the second joint material. It is preferable to be
When the surface modification treatment step is performed by irradiating with vacuum ultraviolet light, the irradiation with vacuum ultraviolet light is performed in an air atmosphere or an atmosphere containing either or both of nitrogen and oxygen. Is preferable.

In the method for producing a bonded structure of the present invention, a protective material made of a transparent resin film as a second bonding member is bonded to one or more surfaces of a polarizing element made of a resin film as a first bonding material. It is suitable for manufacturing a polarizing plate.

Furthermore, in the apparatus for manufacturing the bonded structure of the present invention, the surface modification treatment unit is configured to include a vacuum ultraviolet light irradiation means, a plasma treatment means, a corona treatment means, or an ozone treatment means. preferable.

According to the method and apparatus for manufacturing a bonded structure of the present invention, an organic substance unavoidably produced on the surface of at least one of the bonded materials by the surface modification treatment is removed by the organic substance removing treatment. It is removed to expose the hydrophilized surface of the bonding material. Therefore, since the two bonding materials are directly bonded, a strong bonding state can be obtained, and it is possible to avoid a decrease in bonding strength over time.
In particular, when a resin having an OH group in the chemical structure such as a polyvinyl alcohol-based resin is used as the first bonding material, the OH group is exposed on the surface by the organic substance removal treatment on the first bonding material. A hydrogen bond is formed by the OH group with the second bonding material in the state of being formed, whereby a strong bonding state can be obtained. Moreover, since the first bonding material itself does not deteriorate over time, it is possible to prevent the OH groups involved in the bonding from being lost over time and the bonding strength from decreasing.

It is a figure which shows the outline of the structure in the example of the polarizing plate manufacturing apparatus which concerns on the manufacturing apparatus of the bonded structure of this invention. It is an enlarged view which shows the structure of (a) primary bonding processing part, (b) secondary bonding processing part in the polarizing plate manufacturing apparatus shown in FIG. It is a figure which shows the outline of the structure in the other example of the polarizing plate manufacturing apparatus which concerns on the manufacturing apparatus of the bonded structure of this invention. It is a figure which shows the outline of the structure in still another example of the polarizing plate manufacturing apparatus which concerns on the manufacturing apparatus of the bonded structure of this invention. It is an enlarged view which shows the structure of the bonding processing part in the polarizing plate manufacturing apparatus shown in FIG. It is a figure which shows the outline of the structure in still another example of the polarizing plate manufacturing apparatus which concerns on the manufacturing apparatus of the bonded structure of this invention. It is an AFM photograph of one side of the PVA film for test before performing the surface modification treatment. It is an AFM photograph of one side of the test PVA film after the surface modification treatment. It is an AFM photograph of one side of the test PVA film after the organic matter removal treatment. The X-ray photoelectron spectrum (curve (a)) on the surface of the untreated PVA resin film and the treated surfaces of the PVA resin film and the cycloolefin-based resin film each surface-modified by vacuum ultraviolet light irradiation are joined. It is a figure which shows the X-ray photoelectron spectrum (curve (b)) on the surface (bonding surface) of the PVA resin film which peeled off the cycloolefin resin film after the elapse of a predetermined time time.

Hereinafter, embodiments of the present invention will be described in detail.

[Manufacturing method of joint structure]
The method for producing a bonded structure of the present invention includes a surface modification treatment step for improving the wettability of the surface to be a bonded surface in one or more of the first bonded material and the second bonded material, and the above-mentioned. The organic substance removal treatment step of removing the organic matter generated on the joint surface subjected to the surface modification treatment in the surface modification treatment step, and the joint surface of the first joint material and the second joint material, respectively. It includes a joining process of laminating and joining so that the surfaces to be said to be in close contact with each other.

The first bonding material applied to the present invention and subjected to the surface modification treatment is preferably made of, for example, a resin having a hydrophilic functional group such as an OH group in the chemical structure. Such resins include, for example, polyvinyl alcohol, polyvinyl alcohol-based resins such as ethylene-vinyl alcohol copolymers, resins formed by condensing molecules containing OH groups, such as phenol resins, and molecular terminals. A polyester resin containing an OH group can be exemplified.
The second bonding material is preferably made of, for example, a resin different from that of the first bonding material. As the resin constituting the second bonding material, for example, a cycloolefin-based resin such as a cycloolefin polymer (COP) can be exemplified.
The thickness of the first bonding material and the second bonding material is not particularly limited, but as will be described later, for example, on the surface of at least one of the polarizers as the first bonding material, the second When a polarizing plate formed by joining a protective material as a joining member is formed, the thickness of the first joining material is, for example, 5 to 40 μm, and the thickness of the second joining material is, for example, 10 to 100 μm. is there.

[Surface modification process]
The surface modification treatment step is a step of improving (activating) the wettability of the surface to be the joint surface of one or more of the first joint material and the second joint material, for example, joining. This is a step of imparting hydrophilicity to the surface to be a surface so that the contact angle of pure water is in the range of less than 50 °. Specifically, the surface modification treatment step is preferably performed on at least the first bonding material.
In the surface modification treatment step, one of, for example, vacuum ultraviolet light irradiation treatment, plasma treatment, corona treatment, and ozone treatment is performed on the surface of one joint material and one or more joint surfaces of the second joint material. Although it can be carried out by treatment, it is preferably carried out by vacuum ultraviolet light irradiation treatment.

The vacuum ultraviolet light irradiation treatment is performed by irradiating vacuum ultraviolet light having a wavelength of 200 nm or less. Irradiation with vacuum ultraviolet light is preferably carried out, for example, in an atmospheric atmosphere or an atmosphere containing one or more of nitrogen and oxygen.
The irradiation conditions of vacuum ultraviolet light differ depending on the material of the bonding material to be treated. For example, when the vacuum ultraviolet light irradiation treatment is performed on the first bonding material made of polyvinyl alcohol-based resin, the vacuum ultraviolet light is used. The irradiation amount is, for example, 70 to 1500 mJ / cm ² . Further, for example, when the vacuum ultraviolet light irradiation treatment is performed on the second bonding material made of the cycloolefin resin, the irradiation amount of the vacuum ultraviolet light is, for example, 280 to 3400 mJ / cm ² .

The plasma treatment is performed, for example, by converting the process gas into plasma at atmospheric pressure or its vicinity, and bringing the plasmaized process gas into contact with the surface of the bonding material to be treated.
As the process gas, it is preferable to use a gas containing nitrogen gas, argon gas or the like as a main component and oxygen gas in an amount of 0.01 to 5% by volume. Alternatively, a mixed gas of nitrogen gas and clean dry air (CDA) can be used.
The plasma treatment is performed at a processing speed of, for example, 20 to 500 mm / sec. It is also effective to repeat the plasma treatment a plurality of times.

The corona treatment can be carried out by exposing the bonding material to a corona discharge or by colliding the ions generated by the corona discharge with the bonding material. In addition, ozone treatment can be performed by exposing the bonding material to an ozone atmosphere. The treatment conditions can be appropriately set depending on the material of the bonding material to be treated and the like.

[Organic matter removal process]
The organic matter removing treatment step is the surface of one or more of the first joining material and the second joining material that have been surface-modified in the surface modification treatment step (hereinafter, also referred to as “treated surface”). It is a step of removing the organic matter generated in. When the surface modification treatment is performed on the treated surface in the above surface modification treatment step, the organic substance generated on the treated surface is composed of a water-soluble low molecular weight compound containing an OH group, so that the treated surface is affected. It can be carried out by one or more of a treatment of washing with water and a treatment of heating the treated surface to evaporate organic substances.

The water washing treatment can be performed, for example, by immersing the surface-modified joint material in pure water for a predetermined time.
The temperature of pure water used for the water washing treatment is, for example, about 10 to 30 ° C., and the immersion time of the bonding material is about 5 to 60 seconds.
Further, the water washing treatment may be performed by spraying pure water on the treated surface of the bonded material that has been subjected to the surface modification treatment.

When the organic substance removal treatment step is performed by a water washing treatment, a treatment for removing pure water remaining on the bonding material after the water washing treatment is performed. Specifically, air (dry air) or hot air is blown to the treated surface of the joint material after the water washing treatment, or the treated surface of the joint material after the water washing treatment is heated, or a combination of these treatments is performed. It can be carried out by a drying process such as. In the drying treatment by blowing hot air and heating, the heating temperature is, for example, about 50 to 80 ° C. The processing time of the drying treatment is, for example, about 1 to 5 minutes.

Specific heating conditions in the case where the organic matter removing treatment step is performed by heat treatment are as follows: the heating temperature is, for example, about 50 to 80 ° C., and the treatment time is 80 seconds or more, for example, about 60 to 120 seconds.

[Joining process]
In the joining treatment step, the first joining material and the second joining material are laminated so that the surfaces to be the respective joining surfaces are in close contact with each other, and the first joining material and the second joining material are joined. This is the (bonding) process.
Specific joining treatments for joining the joining materials include (a) a treatment in which the two joining materials are laminated and pressed in the thickness direction for a predetermined time, and (b) a state in which the two joining materials are laminated. The treatment of heating for a predetermined time, (c) a treatment of laminating two bonding materials, pressurizing in the thickness direction for a predetermined time, and then heating for a predetermined time, or (d) two bonding materials. Examples thereof include a process of heating while pressurizing in the thickness direction for a predetermined time in a laminated state. Here, the "predetermined time" is the time until the joining is sufficiently performed.

Specific conditions in the joining process can be appropriately set according to the materials constituting the joining material and the like.
For example, the specific heating conditions for bonding the second bonding material made of a cycloolefin resin to the first bonding material made of a polyvinyl alcohol-based resin are, for example, 60 to 80 ° C. .. The heating time is, for example, 10 to 180 seconds.
Further, as a specific pressurizing condition, the pressing force is 0.1 to 2 MPa. The pressurization time is, for example, 10 to 180 seconds.

[Manufacturing equipment for joint structures]
The apparatus for manufacturing a joint structure of the present invention includes a surface modification treatment portion for improving the wettability of the surface to be a joint surface in one or more of the first joint material and the second joint material, and a surface. The organic matter removing treatment part for removing the organic matter generated on the treated surface subjected to the surface modification treatment in the reforming treatment part, and the first joint material and the second joint material are designated as the respective joint surfaces. It is provided with a joining processing portion for laminating and joining so that the surfaces are in close contact with each other.

The surface modification treatment unit is configured to include a vacuum ultraviolet light irradiation means, a plasma treatment means, a corona treatment means, or an ozone treatment means.

The organic matter removing treatment unit includes one or more of a means for washing the surface (treated surface) of the bonding material that has undergone the surface modification treatment in the surface modification processing unit with water and a means for heating the treated surface of the bonding material. It is said that.
As the washing means, a structure in which the treated surface of the bonding material is immersed in pure water or a structure in which pure water is sprayed on the treated surface of the bonding material can be used.
The heating means can be configured by, for example, a heating furnace or a hot plate.

When the organic matter removing treatment unit is configured to be provided with means for washing the treated surface of the bonding material with water, the configuration is further provided with a drying means for removing water remaining in the bonding material after the water washing treatment and drying the bonding material. It is preferable that it is. The drying means can be composed of a means for blowing dry air, a means for blowing hot air, and a heating means such as a heating furnace or a hot plate. If the configuration is provided with both means for washing the treated surface of the joint material with water and means for heating the treated surface of the joint material, the drying means can be omitted.

The joining processing portion heats the pressurizing means for pressurizing in the thickness direction in a state where the first joining material and the second joining material are laminated, and the state where the first joining material and the second joining material are laminated. It is configured to include one or more of the heating means. Alternatively, the configuration is provided with means for heating while pressurizing in the thickness direction in a state where the first bonding material and the second bonding material are laminated.

In the following, the present invention will be specifically described with reference to a case where a polarizing plate having a protective material made of a transparent resin film is provided on both sides of a polarizing element made of a resin film as an example.

FIG. 1 is a diagram showing an outline of a configuration in an example of a polarizing plate manufacturing apparatus according to the manufacturing apparatus for a bonded structure of the present invention.
In this polarizing plate manufacturing apparatus, the polarizing element supply mechanism 10, the one-sided protective film supply mechanism 30, the other-sided protective film supply mechanism 40, and the one-sided protective film F1 are bonded to one surface of the polarizer P for primary bonding. The primary junction processing unit 50 for obtaining the body L, the polarizer other surface side processing mechanism 60 for the other surface of the polarizing element P in the primary junction L, and the other surface side protective film on the other surface of the polarizer P in the primary junction L. It is provided with a secondary bonding processing unit 53 that joins F2 to obtain a bonding structure (polarizing plate) M, and a recovery mechanism 70 that recovers the bonding structure.

The polarizer supply mechanism 10 includes a polarizer 11 having a polarizer original roll 12 around which a long strip-shaped polarizer P is wound, a polarizer one-sided processing mechanism for one surface of the polarizer P, and a mechanism for processing one surface of the polarizer P. A plurality of transport rollers 13a to 13c are provided as the polarizer transport means. The polarizer P is made of, for example, a uniaxially stretched film made of polyvinyl alcohol resin.
The polarizer one-sided processing mechanism includes a surface modification processing unit 15 and an organic matter removing processing unit 20 arranged at positions along a transport path from the polarizing element supply unit 11 to the primary bonding processing unit 50.

The surface modification processing unit 15 in this example includes, for example, a vacuum ultraviolet light irradiation means 16 that irradiates the surface of the polarizer with vacuum ultraviolet light in an atmospheric atmosphere. Examples of the vacuum ultraviolet light source in the vacuum ultraviolet light irradiation means 16 include an excimer lamp such as a xenon excimer lamp having a emission line at a wavelength of 172 nm, a low-pressure mercury lamp having a emission line at a wavelength of 185 nm, and deuterium having a emission line in the wavelength range of 120 to 200 nm. Although a lamp or the like can be used, it is preferable to use an excimer lamp.

The organic matter removing treatment unit 20 in this example removes, for example, the water washing treatment unit 21 for washing the surface (treated surface) of the polarizing element P subjected to the surface modification treatment and the water remaining on the polarizing element P after the water washing treatment. It is provided with a drying processing unit 25 for processing.
The water washing treatment unit 21 of the polarizer P is composed of, for example, a water washing means 22 having a water tank 23 in which pure water W having a predetermined temperature is stored, and is provided in the water tank 23 in a transport path of the polarizer P. Only one transport roller 13b is arranged in a state where a part thereof is immersed.
The drying processing unit 25 can be composed of, for example, a drying means 26 including a nozzle for blowing dry air (not shown) and a blower (not shown) connected to the nozzle via a filter.

The one-sided protective film supply mechanism 30 is provided from the one-sided protective material supply unit 31 provided with the protective material raw roll 32 around which the long strip-shaped one-sided protective film F1 is wound, and the one-sided protective material supply unit 31. It includes a surface modification processing unit 35 arranged at a position along a transfer path leading to the primary bonding processing unit 50, and a transfer roller 33 as a protective film transfer means. The number of transport rollers as the protective film transport means is not particularly limited.
The surface modification processing unit 35 can have the same configuration as the surface modification processing unit 15 in the polarizing element supply mechanism 10, and is provided with, for example, a vacuum ultraviolet light irradiation means 16. The vacuum ultraviolet light source in the vacuum ultraviolet light irradiation means 16 is, for example, a xenon excimer lamp.

The other-side protective film supply mechanism 40 includes a other-side protective material supply unit 41 provided with a protective material raw roll 42 around which a long strip-shaped other-side protective film F2 is wound, and a other-side protective material. It includes a surface modification processing unit 45 arranged at a position along a transfer path from the supply unit 41 to the secondary bonding processing unit 53, and a transfer roller 43 as a protective film transfer means. The number of transport rollers as the protective film transport means is not particularly limited.
The surface modification processing unit 45 can have the same configuration as the surface modification treatment unit 15 in the polarizer supply mechanism 10, and is provided with, for example, a vacuum ultraviolet light irradiation means 16. The vacuum ultraviolet light source in the vacuum ultraviolet light irradiation means 16 is, for example, a xenon excimer lamp.

The polarizer other surface side processing mechanism 60 includes a surface modification processing unit 61 and an organic matter removal processing unit 62 arranged at positions along a transport path from the primary bonding processing unit 50 to the secondary bonding processing unit 53, and a polarizing element. It is provided with a plurality of transport rollers 65a to 65c as a transport means for a primary bonded body formed by joining both P and the one-side protective film F1.
The surface modification treatment unit 61 and the organic matter removal treatment unit 62 can have the same configuration as the surface modification treatment unit 15 and the organic matter removal treatment unit 20 in the polarizer one-sided treatment mechanism.
For example, the surface modification processing unit 61 is configured to include an ultraviolet light irradiating means 16 that irradiates the other surface of the polarizer P in the primary junction L with vacuum ultraviolet light in an atmospheric pressure atmosphere. The vacuum ultraviolet light source in the ultraviolet light irradiation means 16 is, for example, a xenon excimer lamp.
Further, the organic matter removing treatment unit 62 remains in the water washing treatment unit 63 for washing the surface of the primary joint L that has undergone the surface modification treatment (the other surface of the polarizer P) with water and the primary joint L after the water washing treatment. It is provided with a drying treatment unit 64 for removing water. In the water washing treatment unit 63, for example, one transport roller 65b provided in the transport path of the primary joint L is arranged in a water tank 23 in which pure water W having a predetermined temperature is stored, in a state where a part thereof is immersed. It is composed of the washing means 22 which is configured by the above. The drying processing unit 64 can be composed of, for example, a drying means 26 including a nozzle for blowing dry air (not shown) and a blower (not shown) connected to the nozzle via a filter.

As shown in FIG. 2A, the primary bonding processing unit 50 includes a pair of crimping rollers 51a and 51b arranged so as to be pressed against each other, and the crimping rollers 51a and 51b cause the polarizer P and the one-sided side. The protective film F1 is laminated so that the respective treated surfaces (surfaces to be joined surfaces) Pa and Fa are in close contact with each other, and the bonding treatment is performed by applying pressure.
Further, one or more of the crimping rollers 51a and 51b may have a structure in which a heating means such as a heater is built-in. In such a configuration, the polarizing element P and the one-side protective film F1 are bonded by being pressed while being heated in a state where the respective treatment surfaces Pa and Fa are laminated. It should be noted that the heating means may be separately arranged at a position downstream of the arrangement position of the pair of crimping rollers 51a and 51b.

As shown in FIG. 2B, the secondary joining processing unit 53 includes a pair of crimping rollers 54a and 54b arranged so as to be pressed against each other, and the crimping rollers 54a and 54b cause the primary joining body L and The other surface side protective film F2 is configured such that the bonding process is performed by pressurizing the treated surfaces La and Fb in a laminated state.
Further, one or more of the crimping rollers 54a and 54b may have a structure in which a heating means such as a heater is built-in. In such a configuration, the primary joint L and the other side protective film F2 are laminated while being heated so that the respective treated surfaces (surfaces to be joint surfaces) La and Fb are in close contact with each other. The joining process is performed by being pressed. It should be noted that the heating means may be separately arranged at a position downstream of the arrangement position of the pair of crimping rollers 54a and 54b.

The recovery mechanism 70 includes a joint winding roll 71 that winds and collects the joint structure M in a roll shape.

Thus, in the above-mentioned polarizing plate manufacturing apparatus, the bonded structure (polarizing plate) M is manufactured as follows.

In the polarizer supply mechanism 10, when the polarizer P is sent out from the polarizer original roll 12 in the polarizer supply unit 11 and conveyed to the surface modification processing unit 15, the vacuum constituting the surface modification processing unit 15 is formed. By irradiating one surface of the polarizer P with vacuum ultraviolet light by the ultraviolet light irradiating means 16, a surface modification treatment for improving the wettability of one surface of the polarizer P is performed. Further, by irradiating with vacuum ultraviolet light, organic substances adhering to one surface of the polarizer P are removed. The polarizer P whose surface has been modified by the surface modification processing unit 15 is subsequently sent to the organic substance removal processing unit 20. That is, in the organic matter removing treatment unit 20, first, the water washing treatment unit 21 performs a water washing treatment by immersing the treated surface Pa of the polarizer P in pure water W. As a result, the organic matter generated on one surface of the polarizer P by the vacuum ultraviolet light irradiation is removed. The polarizer P from which the organic matter on the treated surface Pa has been removed by the water washing treatment is subsequently sent to the drying processing unit 25, and the polarizer P is blown by the drying means 26, for example, dry air onto the treated surface Pa of the polarizer P. A drying process is performed to remove the moisture remaining on the surface of the polarized light.

Further, in the one-sided protective film supply mechanism 30, the one-sided protective film F1 is sent out from the protective material raw roll 32 in the one-sided protective material supply unit 31 and conveyed to the surface modification processing unit 35. In the surface modification treatment unit 35, the vacuum ultraviolet light irradiation means 16 irradiates one surface of the one-side protection film F1 with the vacuum ultraviolet light to improve the wettability of one surface of the one-side protection film F1. Quality treatment is done. Further, by irradiating with vacuum ultraviolet light, organic substances adhering to one surface of the one-side protective film F1 are removed.

In this way, the polarizer P and the one-sided protective film F1 each of which has been subjected to surface treatment to be a joint surface are sent to the primary joint processing unit 50 in a state of being synchronized with each other. In the primary bonding processing section 50, the polarizing elements P and the one-side protective film F1 are laminated by the pressure-bonding rollers 51a and 51b so that the respective processing surfaces Pa and Fa are in close contact with each other, while being pressurized or heated. The joining process is performed by applying pressure. As a result, a primary bonded body L in which the one-sided protective film F1 is bonded to one surface of the polarizer P is obtained, and the primary bonded body L is sent to the polarizer other-side processing mechanism 60.

In the polarizer other surface side processing mechanism 60, the primary joint L is conveyed to the surface modification processing unit 61. In the surface modification processing unit 61, the vacuum ultraviolet light irradiation means 16 irradiates the other surface of the polarizer P in the primary junction L with the vacuum ultraviolet light to improve the wettability of the other surface of the polarizer P. Surface modification treatment is performed. Further, by irradiating with vacuum ultraviolet light, organic substances adhering to the other surface of the polarizer P are removed. The primary bonded body L whose surface has been modified on the other surface of the polarizer P in the surface modification processing unit 61 is subsequently sent to the organic substance removal processing unit 62. In the organic matter removing processing unit 62, first, the water washing treatment unit 63 performs a water washing treatment by immersing the treated surface (the other surface of the polarizer P) La of the primary joint L in pure water W. As a result, the organic matter generated on the other surface of the polarizer P by the vacuum ultraviolet light irradiation is removed. The primary joint L from which the organic matter on the treated surface La has been removed by the water washing treatment is subsequently sent to the drying treatment unit 64, and the primary joint L is first blown by the drying means 26, for example, by blowing dry air onto the treated surface La of the primary joint L. A drying treatment is performed to remove the water remaining on the surface of the bonded body L.

On the other hand, in the other side protective film supply mechanism 40, the other side protective film F2 is sent out from the protective material raw roll 42 in the other side protective material supply unit 41 and conveyed to the surface modification processing unit 45. In the surface modification treatment unit 45, the vacuum ultraviolet light irradiation means 16 irradiates one surface of the other surface side protective film F2 with vacuum ultraviolet light to improve the wettability of one surface of the other surface side protective film F2. Surface modification treatment is performed. Further, by irradiating with vacuum ultraviolet light, organic substances adhering to one surface of the other surface side protective film F2 are removed.

In this way, the primary bonded body L and the other surface side protective film F2, each of which has been treated on the surface to be the joint surface, are sent to the secondary joint processing unit 53 in a state of being synchronized with each other. In the secondary bonding processing section 53, the primary bonding body L and the other surface side protective film F2 are laminated by the crimping rollers 54a and 54b so that the respective processing surfaces La and Fb are in close contact with each other, and are pressurized or heated. The joining process is performed by pressurizing while being pressed. As a result, a bonded structure (polarizing plate) M in which the protective film F2 on the other surface side is bonded to the other surface of the polarizer P in the primary bonded body L is obtained. The joint structure M is wound and collected by the joint take-up roll 71 in the recovery mechanism 70.

Therefore, according to the method executed by the above-mentioned polarizing plate manufacturing apparatus, the polarizer P is inevitably generated on the surface of the polarizer P by the surface modification treatment by irradiating the polarizer P with vacuum ultraviolet light. Organic substances derived from hydrophilic functional groups in the constituent material, polyvinyl alcohol resin, are removed by an organic substance removing treatment by washing with water. As a result, the surface of the polarizer P is in a state where the OH groups derived from the constituent materials of the polarizer P are exposed, and is between the surface of the one-side protective film F1 and the other surface of the surface-modified protective film F1. A hydrogen bond due to the OH group is formed with the treated surface of the side protective film F2. Since the composition of the polyvinyl alcohol resin itself as a constituent material of the polarizer P does not change with time, it is possible to prevent a decrease in bonding strength due to deterioration of the OH group involved in bonding with time, and it is reliable. A high bonding state can be obtained.

In the above, the embodiment in which the organic matter removing treatment on the surface of the polarizing element P subjected to the surface modification treatment is performed by the water washing treatment has been described, but when the organic matter removing treatment is performed by the heat treatment, as shown in FIG. In addition, the organic matter removing treatment units 20 and 62 may be configured to include the heating means 29 instead of the water washing means 22 and the drying means 26. Even in a polarizing plate manufacturing apparatus having such a configuration, the same effect as that of the above-mentioned polarizing plate manufacturing apparatus can be obtained.

Further, in the polarizing plate manufacturing apparatus according to the present invention, the one-side protective film F1 and the other-side protective film F2 may be simultaneously bonded to both sides of the polarizing element P.
FIG. 4 is a diagram showing an outline of a configuration in still another example of the polarizing plate manufacturing apparatus according to the apparatus for manufacturing the bonded structure of the present invention.
In this polarizing plate manufacturing apparatus, the polarizing element supply mechanism 10, the one-side protection film supply mechanism 30, the other-side protection film supply mechanism 40, and the one-side protection film F1 and the other-side protection film F1 on both sides of the polarizing element P are provided. It is provided with a joining processing unit 56 for joining the protective film F2 to obtain a joining structure (polarizing plate) M, and a recovery mechanism 70 for recovering the joining structure M. In FIG. 4, the same constituent members in the polarizing plate manufacturing apparatus shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

The polarizer supply mechanism 10 in this polarizing plate manufacturing apparatus has a configuration in which the surface modification processing unit 15 is arranged on one side and the other side with the vacuum ultraviolet light irradiation means 16 sandwiching the transport path of the polarizer P. Other than the above, it has the same configuration as the polarizer supply mechanism 10 in the polarizing plate manufacturing apparatus shown in FIG.

In this polarizing plate manufacturing apparatus, the vacuum ultraviolet light irradiating means 16 and 16 constituting the surface modification processing unit 15 irradiate each of one surface and the other surface of the polarizer P with the vacuum ultraviolet light, thereby causing the polarizing element. A surface modification treatment is performed to improve the wettability of one surface of P and the wettability of the other surface. Further, by irradiation with vacuum ultraviolet light, organic substances adhering to one surface and the other surface of the polarizer P are removed. The polarizer P whose surface has been modified by the surface modification processing unit 15 is subsequently sent to the organic substance removal processing unit 20. That is, in the organic matter removing treatment unit 20, first, the water washing treatment unit 21 performs a water washing treatment by immersing the treated surface of the polarizer P in pure water W. As a result, the organic matter generated on the treated surface of the polarizer P by the vacuum ultraviolet light irradiation is removed. The polarizer P from which the organic matter on the treated surface has been removed by the water washing treatment is subsequently sent to the drying treatment unit 25, and the surface of the polarizer P is sprayed with, for example, dry air by the drying means 26. A drying process is performed to remove the water remaining in the polarized light.

Further, in the one-side protection film supply mechanism 30 and the other-side protection film supply mechanism 40, surface modification by vacuum ultraviolet light irradiation on the surfaces to be joint surfaces of each of the one-side protection film F1 and the other-side protection film F2. Quality treatment is done. Further, by irradiating with vacuum ultraviolet light, organic substances adhering to the one-side protective film F1 and the other-side protective film are removed.

In this way, the polarizer P, the one-sided protective film F1 and the other-sided protective film F2, each of which has been treated on the surface to be the joint surface, are placed on the joint-processed portion 56 in a state of being synchronized with each other. Sent. In the joining processing section 56, as shown in FIG. 5, the processing surface Fa of the one-side protective film F1 and one processing surface Pa of the polarizer are brought into close contact with each other by the crimping rollers 57a and 57b, and the other of the polarizer P is attached. In a state where the treated surface Pb and the treated surface Fb of the other surface side protective film are in close contact with each other and laminated, the joining process is performed by pressurizing or heating while pressurizing. As a result, a bonded structure M is obtained in which the one-sided protective film F1 and the other-sided protective film F2 are bonded to both sides of the polarizer P. The joint structure M is wound and collected by the joint take-up roll 71 in the recovery mechanism 70.

When the organic matter removing treatment is performed by heat treatment, as shown in FIG. 6, the organic matter removing treatment section 20 may be configured to include the heating means 29 instead of the water washing means 22 and the drying means 26. .. Even in a polarizing plate manufacturing apparatus having such a configuration, the same effect as that of the above-mentioned polarizing plate manufacturing apparatus can be obtained.

In the above polarizing plate manufacturing apparatus, a configuration including an organic substance removing processing unit for the one-sided protective film F1 and the other-sided protective film F2, that is, for removing organic substances from the one-sided protective film F1 and the other-sided protective film F2. It may be configured so that processing is performed.
Further, the number of transport rollers as a transport means for transporting the polarizer P, the one-side protective film F1, the other-side protective film F2, the primary joint L, and the joint structure (polarizing plate) M is particularly limited. However, it can be changed as appropriate.

Hereinafter, an example of an experiment conducted to confirm the effect of the present invention will be described.

[Experimental Example 1]
A polarizing element made of a uniaxially stretched film made of polyvinyl alcohol resin having a thickness of 20 μm was cut into a size of 25 × 25 mm and used as a test PVA film. The contact angle of water droplets on one surface of this test PVA film was measured according to JIS R3257 "Test method for wettability of substrate glass surface", and the contact angle was 98 °. Further, when one surface of this test PVA film was observed using an atomic force microscope (AFM), as shown in FIG. 7, nanometer-sized fine particles along the stretching direction caused by the manufacturing reason of the PVA film were observed. No wrinkles (hereinafter referred to as "stretched wrinkles") could be observed. It is considered that the reason for this is that the adhesive component of the trauma-preventing film (which can be easily peeled off), which has been provided since the polarizer was delivered, is attached. The white arrows in FIG. 7 indicate the stretching direction in the process of manufacturing the polarizer. The same applies to FIGS. 8 and 9 shown below.

One surface of this test PVA film is surface-modified by irradiating one surface of the test PVA film with vacuum ultraviolet light having a central wavelength of 172 nm from a xenon excimer lamp under the condition that the irradiation amount is 420 mJ / cm ^2. It was. When the contact angle of water droplets on the treated surface of the PVA film was measured, the contact angle was 14 °. Further, when the treated surface of the test PVA film after the surface modification treatment was observed using an atomic force microscope (AFM), as shown in FIG. 8, stretched wrinkles could not be observed, and a polyvinyl alcohol-based compound was used. It was confirmed that an organic substance (surface treatment product) composed of a low molecular weight compound having an OH group derived from the resin was produced.

Next, the treated surface of the test PVA film that had undergone the surface modification treatment was washed with water by immersing it in pure water at 20 ° C. for 30 seconds, and then the treatment of the test PVA film after the water washing treatment. The surface was subjected to an organic substance removal treatment in which a drying treatment was performed by blowing dry air at 20 ° C. When the treated surface of the test PVA film after the organic matter treatment was observed using an atomic force microscope (AFM), stretched wrinkles were confirmed on the treated surface of the test PVA film as shown in FIG. From this result, it was confirmed that the organic matter produced by the surface modification treatment can be removed by the organic matter removing treatment by the washing treatment and the drying treatment.

[Experimental Example 2]
The same test PVA film as that used in Experimental Example 1 was prepared, and the atmospheric pressure plasma processing device "Aiplasma ANUCL13S-MFNSSV6" (manufactured by Panasonic Corporation) was used on one surface of the test PVA film as follows. The surface modification treatment was performed under the conditions shown in.

(Test condition)
RF power: 172W
Gas used: Ar: 2.14 L / min, O ₂ : 27 mL / min
Distance between nozzle and sample: 5 mm
Treatment speed: 400 mm / sec Plasma treatment under these conditions was repeated 4 times.

When the contact angle on the treated surface of the test PVA film subjected to the surface modification treatment was measured, the contact angle was 12 °. Further, when the treated surface of the test PVA film was observed using an atomic force microscope (AFM), no stretched wrinkles could be observed as in the case of the test PVA film in Experimental Example 1, and a polyvinyl alcohol-based resin was used. It was confirmed that an organic substance (surface treatment product) composed of a low molecular weight compound having an OH group derived from the above was produced.

The treated surface of the test PVA film that has undergone the surface modification treatment is subjected to an organic substance removal treatment by washing with water and a drying treatment by the same method as in Experimental Example 1, and the test PVA film is treated after the organic substance removal treatment. When the surface was observed using an atomic force microscope (AFM), stretched wrinkles were confirmed on the treated surface of the test PVA film. From this result, it was confirmed that the organic matter produced by the surface modification treatment can be removed by the organic matter removing treatment by the washing treatment and the drying treatment.

[Experimental Example 3]
Organic substances produced by the surface modification treatment are removed by the same method as in Experimental Example 1 except that the organic matter removal treatment by heat treatment is performed instead of the organic matter removal treatment by water washing treatment and drying treatment. I checked if I could do it. The heat treatment was carried out using a hot plate by changing the heating temperature and the treatment time according to Table 1 below. The results are shown in Table 1 below. In the evaluation, when the treated surface of the test PVA film after the organic matter removal treatment was observed using an atomic force microscope (AFM), the organic matter was removed and stretched wrinkles could be confirmed (see the state shown in FIG. 9). The case is "○", and some stretched wrinkles can be confirmed, but the case where the organic matter produced by the surface modification treatment is not completely removed is "△", and the stretched wrinkles cannot be confirmed and the surface. The case where the organic matter produced by the reforming treatment was not removed (see the state shown in FIG. 8) was designated as “x”.

From the above results, it was confirmed that the organic matter produced by the surface modification treatment can be removed by the organic matter removing treatment by the heat treatment by appropriately setting the heating temperature and the treatment time.

[Experimental Example 4]
A test was conducted by adhering a 60 μm-thick triacetyl cellulose (TAC) resin film to the other surface of a polarizing element made of a uniaxially stretched film made of polyvinyl alcohol resin having a thickness of 20 μm cut to a size of 25 × 130 mm. PVA film for use was obtained. The contact angle of water droplets on one surface of this test PVA film was measured according to JIS R3257 "Test method for wettability of substrate glass surface", and the contact angle was 98 °.
Further, a bonding material obtained by cutting a cycloolefin resin (COP) film having a thickness of 50 μm into a size of 25 × 130 mm was prepared. The contact angle of water droplets on one surface of this bonding material was 99 °.

One surface of this test PVA film is surface-modified by irradiating one surface of the test PVA film with vacuum ultraviolet light having a central wavelength of 172 nm from a xenon excimer lamp under the condition that the irradiation amount is 420 mJ / cm ^2. It was. When the contact angle of water droplets on the treated surface of the PVA film was measured, the contact angle was 14 °.
Further, one surface of the bonding material was surface-modified by irradiating one surface of the bonding material with vacuum ultraviolet light having a central wavelength of 172 nm from a xenon excimer lamp under the condition that the irradiation amount was 2540 mJ / cm ² . .. When the contact angle of water droplets on the treated surface of the PVA film was measured, the contact angle was 13 °.

One side of the test PVA film that has undergone surface modification treatment is washed with water by immersing it in pure water at 20 ° C for 30 seconds, and dry air at 20 ° C is applied to one side of the test PVA film after the water washing treatment. Organic matter removal treatment was performed by performing a drying treatment by spraying. Next, the test PVA film and the bonding material were laminated so that the treated surfaces were in close contact with each other, and the test PVA film and the bonding material were bonded using a laminator "Proteus A3" (manufactured by Fellows Japan Co., Ltd.). The roller heating temperature in the laminator was 60 ° C., and the feed rate of the laminate of the test PVA film and the bonding material was 6 mm / sec.

Two bonding structures thus obtained were produced, and for each bonding structure, the bonding strength between the test PVA film and the bonding material was measured at a peeling rate of 300 mm / min by a T-type peeling test. .. The peeling test for one bonded structure is performed immediately after joining, and the peeling test for the other bonded structure is performed by leaving the bonded structure in an air atmosphere having a temperature of 15 to 25 ° C and a humidity of 50 to 60%. , 48 hours after joining was performed. The results are shown in Table 2 below.

[Experimental Example 5]
Two bonded structures were produced by the same method as in Experimental Example 4, except that the organic matter removal treatment by heat treatment was performed instead of the organic matter removal treatment by water washing treatment and drying treatment. The heat treatment was performed using a hot plate, the heating temperature was 60 ° C., and the treatment time was 60 seconds.
For each bonded structure, the bonding strength between the test PVA film and the bonding material was measured by the same method as in Experimental Example 4. The results are shown in Table 2 below.

[Experimental Example 6]
Two bonded structures were prepared by the same method as in Experimental Example 4, except that the organic matter removal treatment was performed by performing a heat treatment in addition to the water washing treatment and the drying treatment. The heat treatment was performed using a hot plate, the heating temperature was 60 ° C., and the treatment time was 60 seconds.
For each bonded structure, the bonding strength between the test PVA film and the bonding material was measured by the same method as in Experimental Example 4. The results are shown in Table 2 below.

[Comparative Experiment Example 1]
With respect to the test PVA film, two bonded structures were prepared by the same method as in Experimental Example 4, except that the one surface to which the surface was modified was not subjected to the organic substance removal treatment.
For each bonded structure, the bonding strength between the test PVA film and the bonding material was measured by the same method as in Experimental Example 4. The results are shown in Table 2 below.

As shown in Table 2, immediately after joining, the joining strength is high and the joining material is broken in any of the joining structures regardless of the presence or absence of the organic substance removal treatment. However, when 48 hours have passed since the bonding, in the bonding structure according to Comparative Experimental Example 1 in which the organic substance removal treatment was not performed, the bonding strength may decrease and the bonding material may be easily peeled off. confirmed.

10 Polarizer supply mechanism 11 Polarizer supply unit 12 Polarizer original roll 13a to 13c Conveyor roller 15 Surface modification processing unit 16 Vacuum ultraviolet light irradiation means 20 Organic matter removal processing unit 21 Water washing treatment unit 22 Water washing means 23 Water tank 25 Drying treatment Part 26 Drying means 29 Heating means 30 One side protective film supply mechanism 31 One side protective material supply part 32 Protective material original roll 33 Conveyor roller 35 Surface modification processing part 40 Other side protective film supply mechanism 41 Other side protective material Supply unit 42 Protective material Raw fabric roll 43 Conveying roller 45 Surface modification processing unit 50 Primary bonding processing unit 51a Crimping roller 51b Crimping roller 53 Secondary bonding processing unit 54a Crimping roller 54b Crimping roller 56 Crimping processing unit 57a Crimping roller 57b Crimping roller 60 Polarizer Other side treatment mechanism 61 Surface modification treatment part 62 Organic matter removal treatment part 63 Water washing treatment part 64 Drying treatment part 65a to 65c Conveyor roller 70 Recovery mechanism 71 Joined winding roll F1 One side protective film Fa treatment surface F2 Other side protective film Fb treated surface L primary bonded La treated surface M bonded structure (polarizing plate)
P Polarizer Pa Treatment surface Pb Treatment surface W Pure water

Claims (8)

It is a method of manufacturing a joint structure formed by joining a second joint material to a first joint material.
A surface modification treatment step for improving the wettability of the surface to be the joint surface of one or more of the first joint material and the second joint material, and
An organic substance removal treatment step of heating and removing the organic matter generated on the joint surface that has been surface-modified in the surface modification treatment step so that the organic substance is removed.
Manufacture of a joining structure including a joining treatment step of laminating the first joining material and the second joining material so that the surfaces to be the respective joining surfaces are in close contact with each other and joining them. Method. The bonding material subjected to the surface modification treatment in the surface modification treatment step is the first bonding material.
The method for producing a bonded structure according to claim 1, wherein the first bonding material is made of a resin having an OH group in the chemical structure. The method for producing a bonded structure according to claim 2, wherein the first bonding material is made of a polyvinyl alcohol-based resin. The method for producing a bonded structure according to claim 2 or 3, wherein the second bonding material is made of a resin different from that of the first bonding material. Claims 1 to 1, wherein the surface modification treatment step is performed by irradiating the surface of one or more of the first bonding material and the second bonding material, which is to be a bonding surface, with vacuum ultraviolet light. The method for producing a bonded structure according to any one of claims 4. The bonded structure according to claim 5, wherein in the surface modification treatment step, irradiation with vacuum ultraviolet light is performed in an air atmosphere or an atmosphere containing one or more of nitrogen and oxygen. Manufacturing method. The surface modification treatment step is performed by any of corona treatment, plasma treatment, and ozone treatment on the surface of one or more joint surfaces of the first joint material and the second joint material. The method for manufacturing a bonded structure according to any one of claims 1 to 6, wherein the bonded structure is characterized. The bonding structure is a polarizing plate in which a protective material made of a transparent resin film as a second bonding member is bonded to one or more surfaces of a polarizing element made of a resin film as a first bonding material. The method for producing a bonded structure according to any one of claims 4 to 7, wherein the bonded structure is characterized.