KR20130018573A - Joining method for resin members - Google Patents

Abstract

The subject of this invention is providing the joining method of the resin member which suppresses a break in the joining of the resin member using a laser beam.
The joining method of the resin member includes a step of arranging a plurality of resin members so that at least a portion thereof overlaps, and the pressing member 50 is scanned while pressing the overlapping portion with the glass pressing member 50. The process of irradiating the laser beam L with the overlap part is provided. In the step of irradiating, the pressing time by the pressing member 50 is set to 3 msec or more and 600 msec or less.

Description

Joining method of resin member {JOINING METHOD FOR RESIN MEMBERS}

This invention relates to the bonding method of a resin member, More specifically, it contains the polarizing film used for image display apparatuses, such as a liquid crystal display device, an electroluminescence (EL) display device, a plasma display, a field emission display, etc. It is related with the bonding method by the laser of an optical film.

DESCRIPTION OF RELATED ART Conventionally, in the image display apparatuses, such as a liquid crystal display device, the optical film containing a polarizing film etc. is used.

As a manufacturing method of such a polarizing film, the strip | belt-shaped polyvinyl alcohol (PVA) system raw material film is sent out through a predetermined | prescribed movement path, sending out from a front end side, and it extends in the said movement path, and the method of making a polarizing film is employ | adopted.

For example, a raw material film is sent out from a raw material roll formed by winding a band-shaped polyvinyl alcohol-based raw material film in a roll shape, and the raw material film is passed through various raw materials such as a dye bath by regulating a moving path with a plurality of rollers. The method of making a polarizing film by extending | stretching and extending | stretching the dyed film in a movement path is employ | adopted.

By the way, in the manufacturing method of such a polarizing film, it is very complicated and wasteful time to manually pass the front end side of each raw material film in the movement path regulated by a roller or the like, so that the next raw material on the end side of the preceding raw material film Bonding the tip end side of the film to form a polarizing film successively is performed.

As the bonding means at this time, conventional bonding adhesive means such as an adhesive tape or an adhesive, suture bonding means by rivets or seals, heat melt bonding means by a heat sealer or the like (for example, JP 2007-171897A (Patent Document 1) ) And Japanese Patent Laid-Open No. 2010-8509 (Patent Document 2)).

However, each of the above joints has the following problems.

Problems in adhesive bonding with adhesive tapes or adhesives

In the process of immersing in chemical liquids such as swelling and dyeing, the adhesive or adhesive melts in the chemical liquid to contaminate the chemical liquid and cause the adhesion of foreign substances to the product. It lowers and a raw material break may generate | occur | produce before reaching a desired draw ratio in an extending process.

Problems in suture bonding due to rivets or threads

Since wrinkles generate | occur | produce in a bonding part, it becomes a cause of extending | stretching nonuniformity of a polarizing film. In addition, since the bonding strength is low, breakage of raw materials may occur before the desired draw ratio is reached, similarly to the adhesive bonding means.

Problems in hot melt bonding by heat sealer or the like

Since it is difficult to heat only a narrow area with a heat sealer, it hardens locally by the high crystallinity of a junction part and its periphery part by a wide area heating and heat transfer to the periphery. For this reason, when extending | stretching load is enlarged in order to improve the characteristic of a polarizing film, raw material fracture may generate | occur | produce.

Thus, as disclosed in Japanese Patent No. 3927958 (Patent Document 3) in addition to the above bonding, it is conceivable to apply a technique using a laser beam as the bonding means.

Japanese Patent Publication No. 2007-171897 Japanese Patent Publication No. 2010-8509 Japanese Patent No. 3929958

However, when extending | stretching 5.25 times or more like the case of manufacturing a polarizing film to the joined body bonded by the bonding method of the said patent document 3, for example, since bonding is not enough, a breakage may arise.

This invention makes it a subject to provide the joining method of the resin member which suppresses a break in the joining of the resin member using a laser beam in view of the said problem.

The joining method of the resin member of this invention arrange | positions a some resin member so that at least one part may overlap, and injects the said pressing member, pressing the overlapping part with a glass pressing member, and at the overlapping part via the said pressing member, The process of irradiating a laser beam is provided, The irradiation process is characterized by making the pressurization time by the said press member into 3 msec or more and 600 msec or less.

As a result of earnest research by the present inventors, in the method of joining a resin member using a laser beam, it discovered that the joining strength in a junction part is raised by making time to press an overlap part into the said range.

Specifically, if the pressurization time is less than 3 msec, the pressurization time is too short. Therefore, the pressurization by the pressurizing member is opened before the joining reaction is completed, and it is difficult to obtain a sufficient joining state. On the other hand, if the pressurization time exceeds 600 msec, the pressurization time is too long, causing high crystallization by heat transfer to the junction and its periphery, and stress is concentrated on the junction and its periphery when a large stretching load is applied. Done.

Therefore, even if extending | stretching the time which presses an overlapping part in the said range, even when extending | stretching the joined resin member, the joining method of the resin member which suppresses the fracture | rupture at a joining part can be provided.

In the joining method of the said resin member, Preferably, the rotatable cylindrical or spherical pressing member is used at the process to irradiate.

Thereby, the pressing member can be easily scanned. For this reason, since the pressurization time of the whole superimposition part can be controlled more correctly, the fracture of a junction part can be suppressed more.

In the bonding method of the said resin member, Preferably, in the process of arrange | positioning, it arrange | positions so that an overlap part may overlap through a light absorber.

Thereby, when a some resin member is a material which does not absorb a laser beam, since a laser beam is absorbed at an overlap part, the reliability of joining in a junction part can be improved.

In the joining method of the said resin member, Preferably, at the process to irradiate, the infrared laser of the wavelength of 800 nm or more and 11000 nm or less is irradiated.

Thereby, bonding strength can be especially improved with respect to a polyvinyl alcohol-type resin film.

In the joining method of the said resin member, Preferably, the resin member which has a thickness of 3 micrometers or more and 300 micrometers or less is used at the process of arrange | positioning.

When thickness is 3 micrometers or more, the fall of mechanical strength can be suppressed, and when the thickness is 300 micrometers or less, the fall of an optical characteristic can be suppressed, and even if it is applied to an image display apparatus, thickness can be achieved.

In the bonding method of the said resin member, Preferably, the process of arrange | positioning uses the optical film containing a polarizing film as a resin member.

Since the bonding method of the resin member of this invention can suppress the fracture | rupture at a junction part, it is used especially suitably for the optical film containing the polarizing film in which big extending | stretching is desired.

As described above, according to the present invention, since the laser light is irradiated with the pressurization time of the pressing member being 3 msec or more and 600 msec or less, a method of joining the resin member which suppresses breakage in joining the resin member using the laser light is provided. can do.

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which shows schematically the apparatus used for the manufacturing method of the polarizing film of embodiment of this invention.
FIG. 2 is a perspective view schematically showing a state in which a raw material film is bonded in an embodiment of the present invention and supplied to a manufacturing apparatus of a polarizing film. FIG.
It is a side view which shows schematically the bonding apparatus for bonding the raw material film in embodiment of this invention.

EMBODIMENT OF THE INVENTION Below, the example applied to the manufacturing method of a polarizing film is demonstrated about one Embodiment which concerns on the bonding method of the resin member of this invention.

Specifically, it demonstrates, illustrating the case where a polarizing film is manufactured by bonding strip | belt-shaped polyvinyl alcohol-type resin films, and supplying these polyvinyl alcohol-type resin films to a stretching apparatus continuously.

First, the preferable extending | stretching apparatus for implementing the manufacturing method of the polarizing film of this embodiment is demonstrated, referring drawings.

As shown in Figs. 1 and 2, the stretching apparatus is a raw material film from a raw material roll in which a strip-shaped polyvinyl alcohol-based resin film (hereinafter also referred to as a "raw material film" or simply "film") is wound in a roll shape. Raw material film supply part 3 for sending out (1), a plurality of immersion baths 4 for immersing the sent raw material film 1 in a predetermined chemical liquid, and the raw material film 1 in the immersion bath 4. Is immersed in a plurality of rollers 9 for restricting the movement path of the raw material film 1 to pass through, a drawing portion for stretching the raw material film 1 in the moving path, and a plurality of immersion baths 4. Moreover, the polarizing film winding part 10 for winding up the stretched film in roll shape as a polarizing film is provided.

As shown in FIG. 1 and FIG. 2, the swelling bath 4a in which the swelling liquid which swells the polyvinyl alcohol-type resin film in order from the flow direction upstream of the film as the plurality of immersion baths 4 is stored. A dyeing bath (4b) in which a dye solution for dyeing a film is stored, a crosslinking bath (4c) in which a crosslinking agent solution for crosslinking molecular chains of the resin constituting the film is stored, and a stretching bath (4d) for stretching the film in the bath. ) And the stretching apparatus is equipped with five types of immersion baths 4 called the washing bath 4f in which the washing | cleaning liquid which wash | cleans the film which passed the said stretching bath 4d was stored.

Moreover, the said stretching apparatus is a downstream apparatus of the washing | cleaning bath 4f in the movement path of the film 1, and the drying apparatus which dries the washing | cleaning liquid attached to the film 1 on the upstream side of the winding-up part 10 ( 11) Specifically, a drying oven is provided.

Moreover, in the said stretching apparatus, the film 12 for lamination | stacking, such as the surface protection film (for example, a triacetyl cellulose film or a cycloolefin polymer film) wound in roll shape on both sides of the film dried by the drying apparatus 11, This is arranged. The stretching apparatus is equipped with the lamination apparatus for laminating | stacking the film 12 for lamination | stacking on both surfaces of the film after drying.

As a stretch part, what is called a roll extending means is employ | adopted. That is, a plurality of pairs of paired nip rollers 9a arranged to sandwich the film 1 in the moving path and to feed the downstream side in the flow direction are arranged, and the peripheral speed of the set on the downstream side in the flow direction is the upstream side. Furthermore, the structure which becomes high speed is employ | adopted.

In addition, as shown in FIG. 2, the stretching apparatus has a raw material film 1 before the end portion 1a of the raw material film 1 passes through a regulated movement path, specifically, before passing through the immersion bath 4. And a bonding apparatus (see Fig. 3) for connecting the distal end portion 1a of the end portion 1a and the distal end portion 1b of the new raw material film 1 to pass through the raw material film 1 in the movement path by laser welding. .

In addition, in FIG. 2, the part joined by laser irradiation is shown by the black 30. As shown in FIG.

Next, the bonding apparatus of this embodiment is demonstrated with reference to FIG. 3 shows the side surface of the bonding apparatus when the overlapping part of the raw material film of the new and old to be bonded is seen from the one side surface.

As shown in this FIG. 3, the bonding apparatus of this embodiment is arrange | positioned on the interposition member 40 arrange | positioned on the overlapping part of the distal end part 1a and the front-end | tip part 1b of a film, and this interphase member 40. It has a pressurizing member 50 and the laser irradiation part 60 arrange | positioned on the pressurizing member 50. FIG. In the bonding apparatus of the present embodiment, the distal end portion 1a of the preceding raw material film 1 and the distal end portion 1b of the new raw material film 1 connected thereto are overlapped vertically, and the overlapping portion is formed between the upper and lower members 40. The laser beam L is irradiated from the laser irradiation part 60 while pressurizing with the press member 50, and it is comprised so that the interface part of the terminal part 1a and the front end part 1b may be melted and welded.

The pressing member 50 is comprised from glass which shows high transparency with respect to the laser beam L to be used. The pressing member 50 can scan the overlapping portion of the raw material film 1.

The pressing member 50 is not particularly limited as long as the pressing member is pressurized so that the pressing time is 3 msec or more and 600 msec or less. However, the pressing member 50 has a rotatable cylindrical or spherical shape in that the overlapping portion of the raw material film 1 can be easily scanned. desirable.

The pressing member 50 is preferably configured to have a pressurization strength of 0.5 kgf / cm 2 or more and 200 kgf / cm 2 or less, more preferably 30 kgf / cm 2 or more and 150 kgf / cm 2 or less.

The material constituting the pressing member 50 is not particularly limited as long as it is made of glass. For example, quartz, alkali-free glass, tempax, pyrex, bicore, D263, OA10, AF45 and the like can be used.

In order to increase the utilization efficiency of the laser light L, the pressing member 50 preferably has high transparency to the wavelength of the laser light L to be used, preferably has a light transmittance of 50% or more, and has a light transmittance of 70% or more. It is more preferable to have.

The interphase member 40 is disposed so as to cover approximately the entire overlapping portion of the raw material film 1 in order to suppress warpage, misalignment and the like of the raw material film 1 due to the movement of the pressing member 50. It may be arrange | positioned so that at least one part of the non-bonded part in the raw material film 1 may be covered.

50 micrometers or more and less than 10 mm are preferable, and, as for the thickness of the interphase member 40, 1 mm or more and less than 5 mm are more preferable. If it is 50 micrometers or more, handling will become easy, and if it is 1 mm or more, handling will become easier. In the case of less than 10 mm, the efficiency of laser beam L reaching the overlapped portion can be suppressed from being absorbed or scattered, and in the case of less than 5 mm, the efficiency of laser beam L reaching the overlapped portion is lowered. It can be suppressed.

Although the interphase member 40 is not specifically limited, It is preferable to have a light transmittance of 30% or more with respect to the wavelength of the laser beam L to be used, and it is more preferable to have a light transmittance of 50% or more.

The material constituting the interphase member 40 is preferably, for example, a rubber having good light transmittance, a resin material having a cushion property, or the like. As such a material, rubber-based materials, such as silicone rubber and urethane rubber, and resin materials, such as polyethylene, can be used, for example.

The interphase member 40 may be one layer or a plurality of layers. When the interphase member 40 has a plurality of layers, in addition to the layer of the material, for example, polycarbonate, polyethylene terephthalate, norbornene resin, cycloolefin polymer, polymethyl methacrylate, polyimide, triacetyl cellulose Etc. can be laminated | stacked and used. When the upper phase member 40 is a single | mono layer, you may use said various resin materials as a single | mono layer.

The laser irradiation part 60 irradiates the laser beam L through the press member 50 along the overlapping part of the old and new raw material film 1. Since the pressurizing member 50 can be scanned, it is preferable that the laser light source of the laser irradiation part 60 can also be scanned. As such a structure, the laser irradiation part 60 has a mechanism for scanning the spot beam collected by the condensing lens to the desired beam size, for example, along the overlapping portion of the old and new raw material film 1.

In this embodiment, the laser beam L irradiated from the laser irradiation part 60 is absorbed by the light absorbing agent arrange | positioned by means, such as application | coating to one or both sides, in the middle (interface) of the overlapping part which superimposed the old and new raw material film 1. When the absorption sensitivity of the light absorbing agent to be used is high, the type of laser is not particularly limited. The laser light L to be irradiated is preferably a solid state laser such as a semiconductor laser, a fiber laser, a femtosecond laser, a picosecond laser, a YAG laser, or a gas laser such as a CO ₂ laser having an visible light region or an infrared region. More preferably, a semiconductor laser or a fiber laser can easily obtain a uniform laser beam. In addition, the CW laser of continuous wave is more preferable than the pulse laser which inputs high energy instantaneously for the purpose of avoiding decomposition of the raw material film 1 and promoting melting.

The output (power), beam size, shape, number of irradiations, scanning speed, and the like of the laser light L irradiated from the laser irradiation unit 60 may include optical characteristics such as light absorption of the raw material film 1 and the light absorbing agent to be bonded. It selects suitably with respect to a difference, such as melting | fusing point and thermal characteristics, such as glass transition point Tg. In the case where polyvinyl alcohol-based resin is used as the raw material film 1, the laser irradiation part 60 is preferably 200 W / cm 2 or more in order to efficiently fluidize the polyvinyl alcohol-based resin of the laser irradiation part to obtain a high strength bonding. The laser beam L having a power density of 10000 W / cm 2 or less, more preferably 300 W / cm 2 or more and 5000 W / cm 2 or less, particularly preferably 1000 W / cm 2 or more and 3000 W / cm 2 or less can be irradiated.

Moreover, it is preferable that the laser irradiation part 60 is comprised so that it may have an irradiation beam area (irradiation width or spot diameter) 1/10 or more and 5 times or less of the old and new raw material film overlap width with the power which satisfy | fills irradiation laser power density. When the irradiation width is 1/10 or more of the overlapping width, since the joint in the overlapping portion is large, it is possible to suppress the fluctuation when conveying after the bonding and to suppress the satisfactory conveyability. When the laser beam L is irradiated with a width of 5 times or less, the influence on the bonding and stretching characteristics is small, and the energy utilization efficiency is good. From this viewpoint, it is more preferable that irradiation width is 1/5 or more and 3 times or less of overlapping width.

Further, the laser irradiation unit 60 preferably irradiates an integrated irradiation amount of 5 J / cm 2 or more and 400 J / cm 2 or less, more preferably 10 J / cm 2 or more and 300 J / cm 2 or less, particularly preferably 30 J / cm 2 or more and 150 J / cm 2 or less. It is configured to be possible.

The beam shape of the laser beam L may be circular or may be linear in order to obtain high power density.

In addition, the bonding apparatus in this embodiment may further have a stage (not shown) which mounts the raw material film 1 to bond | bond. Such a stage can employ | adopt what the upper surface part is formed with metal, glass, resin, rubber | gum, a ceramic, etc., for example.

In addition, although it is not demonstrated in detail here, the said bonding apparatus can employ | adopt various mechanisms used by a general laser welding apparatus and its peripheral apparatus.

Then, the method to manufacture a polarizing film using the extending | stretching apparatus provided with such a bonding apparatus is demonstrated.

In the manufacturing method of the polarizing film of this embodiment, the swelling process of dipping and swelling the strip | belt-shaped raw material film 1 in the swelling bath 4a, and the dyeing process of dipping and swelling the swelled film in the dyeing bath 4b, and dyeing; A crosslinking step of immersing the dyed film in the crosslinking bath 4c to crosslink the molecular chains of the resin constituting the film, a stretching step of stretching the film after the crosslinking step in the stretching bath 4d, and the stretching step The washing | cleaning process which wash | cleans a subsequent film, the drying process which dries the said washed film with the drying apparatus 11, and the lamination process which laminates a surface protection film on the film after the said drying are performed.

And in the manufacturing method of the polarizing film of this embodiment, one raw material roll is set to the raw material film supply part 3, the raw material film is sent out continuously from this raw material film supply part 3, and the said process is performed by the movement path. It implements by carrying out the winding process which winds up the product (polarizing film) which carried out and finally the lamination process is carried out in roll shape in the polarizing film winding-up part 10.

In addition, using the above-mentioned bonding apparatus, before a winding process of a raw material roll is complete | finished, a raw material film is taken out from a new raw material roll, and is made to the end part 1a of the raw material roll which precedes the front-end | tip 1b of this new raw material film. By performing the bonding process to bond separately, a raw material film is subsequently supplied from this new raw material roll to a stretching apparatus, and a polarizing film is continuously manufactured.

Although the raw material film provided in the said process is not specifically limited, As a strip | belt-shaped polyvinyl alcohol-type resin film, it is a polyvinyl alcohol-type high molecular resin material used as a polarizing film, A polyvinyl alcohol film, a partially saponified polyvinyl alcohol film, or poly Vinyl alcohol dehydration film, etc. can be used.

Usually, these raw material films are used in the state of the raw material roll wound by roll shape as demonstrated above.

The polymerization degree of the polymer which is a material of the said polyvinyl alcohol-type raw material film is generally 500 or more and 10000 or less, It is preferable that it is the range of 1000 or more and 6000 or less, It is more preferable to exist in the range of 1400 or more and 4000 or less.

In the case of the partially saponified polyvinyl alcohol film, the saponification degree is preferably 75 mol% or more, for example, in terms of solubility in water, more preferably 98 mol% or more, and 98.3 mol% or more and 99.8 mol%. It is more preferable to exist in the following ranges.

As a manufacturing method of the said polyvinyl alcohol-type raw material film, what was formed by arbitrary methods, such as the casting method, the casting method, and the extrusion method which cast-forms the stock solution melt | dissolved in water or an organic solvent, can be used suitably.

It is preferable that the retardation value of a raw material film is 5 nm or more and 10 nm or less.

Moreover, in order to obtain an in-plane uniform polarizing film, it is preferable that the retardation deviation in the polyvinyl alcohol-based raw material film plane is as small as possible, and the in-plane retardation deviation of the polyvinyl alcohol-based film as the raw material film is 10 at a measurement wavelength of 1000 nm. It is preferable that it is nm or less, and it is more preferable that it is 5 nm or less.

As an absorption (function) state when a polyvinyl alcohol-type raw material film is joined, it is preferable to have an absorptivity of 2 mass% or more and 15 mass% or less, and it is more preferable to have an absorption rate of 4 mass% or more and 10 mass% or less. When the non-connected raw material film has an absorptivity of 15% by mass or less, it is possible to suppress the heat-melting portion from foaming by water evaporation and to reduce the bonding failure. When water absorption is 10 mass% or less, a poor bonding can be suppressed more. On the other hand, when water absorption is 2 mass% or more, resin fluidity at the time of the heating of the raw material film which is not bonded is favorable, and the fall of bonding efficiency can be suppressed. When water absorption is 4 mass% or more, the fall of joining efficiency can be suppressed more.

In addition, about the said light absorptivity, the transmittance | permeability: T (%) and reflectance: R (%) of a target wavelength range by an integrating sphere mode using Nihon Bunko Corporation, an ultraviolet visible near-infrared spectrophotometer, and a product name "V-670". Can be obtained by calculating the following equation.

Light absorption rate: A (%) = 100-T-R

In addition, about water absorption, it is calculated | required by comparing the mass before and behind drying, for example, if it is a polyvinyl alcohol-type resin film, it heats 83 degreeC * 1 hour, and divides the heating loss by the mass of the polyvinyl alcohol-type resin film before heating, You can get it.

Next, each process for extending | stretching to the said raw material film with the said extending | stretching apparatus and processing to a polarizing film is demonstrated.

(Swelling process)

In this process, the raw material film sent out from the raw material film supply part 3 is guided by the swelling bath 4a filled with water, for example, and the raw material film is immersed in water, keeping the moving speed constant by the roller 9.

As a result, the raw material film is washed with water, and the contamination or blocking blocking agent on the surface of the raw material film can be washed, and the effect of preventing nonuniformity such as dyeing stains can be expected by swelling the raw material film with water.

Glycerin, potassium iodide, etc. may be added to the swelling liquid in the swelling bath 4a suitably in addition to water, and when adding these, it is preferable to set it as 5 mass% or less if it is glycerin, and 10 mass% or less if it is potassium iodide. Do.

It is preferable to make temperature of a swelling liquid into the range of 20 degreeC or more and 45 degrees C or less, and it is more preferable to set it as 25 degreeC or more and 40 degrees C or less.

The immersion time during which the raw material film is immersed in the swelling liquid is preferably 2 seconds or more and 180 seconds or less, more preferably 10 seconds or more and 150 seconds or less, and particularly preferably 30 seconds or more and 120 seconds or less.

Moreover, you may extend | stretch a polyvinyl alcohol-type resin film in the longitudinal direction in this swelling bath, It is preferable to make it the draw ratio at that time about 1.1 times or more and 3.5 times or less including the extension by swelling.

(Dyeing process)

The film which passed through the said swelling process is immersed in the dye solution stored in the dyeing bath 4b by the roller 9 similarly to a swelling process, and a dyeing process is performed.

For example, this dyeing step can be carried out by employing a method of adsorbing the dichroic material to the film by immersing the polyvinyl alcohol-based resin film that has undergone the swelling step in a dyeing solution containing a dichroic material such as iodine. .

As said dichroic substance, a conventionally well-known substance can be used, For example, iodine, an organic dye, etc. are mentioned.

As an organic dye, for example, red BR, red LR, red R, pink LB, ruby BL, Bordeaux GS, sky blue LG, lemon yellow, blue BR, blue 2R, navy RY, green LG, violet LB, violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Sprue Blue G, Sprue Blue GL, Sprue Orange GL , Direct sky blue, direct first orange S, first black and the like can be used.

1 type of these dichroic substances may be used and they may use two or more types together.

When using the said organic dye, in order to neutralize visible region, for example, it is preferable to combine two or more types.

As a specific example, the combination of Congo red and sprue blue G, the sprue orange GL, and direct sky blue, or the combination of direct sky blue and first black etc. are mentioned.

As the dye solution of the dyeing bath, a solution in which the dichroic substance is dissolved in a solvent can be used. As a solvent, although water can be used generally, you may add and use the organic solvent compatible with water further.

As a density | concentration of the dichroic substance in this dyeing liquid, it is preferable to set it as the range of 0.010 mass% or more and 10 mass% or less, It is more preferable to set it as 0.020 mass% or more and 7 mass% or less, More preferably, it is 0.025 mass% or more and 5 mass% It is especially preferable to set it as% or less.

In addition, when iodine is used as a dichroic substance, it is preferable to add an iodide further at the point which can improve dyeing efficiency further.

Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, titanium iodide and the like.

It is preferable to set it as 0.010 mass% or more and 10 mass% or less in the said dyeing bath, and, as for the addition ratio of these iodide, it is more preferable to set it as 0.10 mass% or more and 5 mass% or less.

Among these, it is preferable to add potassium iodide, the ratio (mass ratio) of iodine and potassium iodide is preferably in the range of 1: 5 to 1: 100, more preferably in the range of 1: 6 to 1:80. And it is especially preferable to set it as the range of 1: 7-1: 70.

Although the immersion time of the film in the said dyeing bath is not specifically limited, It is preferable to set it as the range of 0.5 to 20 minutes, and the range of 1 to 10 minutes is more preferable. Moreover, it is preferable to set it as the range of 5 degreeC or more and 42 degrees C or less, and, as for the temperature of a dyeing bath, it is more preferable to set it as the range which is 10 degreeC or more and 35 degrees C or less.

Moreover, you may extend | stretch a film in a longitudinal direction in this dyeing bath, and it is preferable to make the accumulated total draw ratio into about 1.1 times or more and about 4.0 times or less.

As the dyeing step, in addition to the method of immersing in the dyeing bath as described above, for example, a method of applying or spraying an aqueous solution containing a dichroic substance to the polymer film may be employed.

Moreover, in this invention, the film formed into the polymer raw material previously mixed with a dichroic substance may be employ | adopted as a raw material film used without performing a dyeing process.

(Cross-linking process)

Next, a film is introduce | transduced into the crosslinking bath 4c which stores a crosslinking agent liquid, a film is immersed in a crosslinking agent liquid, and a crosslinking process is performed.

Conventionally well-known substances can be used as a crosslinking agent, For example, boron compounds, such as a boric acid and a borax, glyoxal, glutaraldehyde, etc. can be used. These crosslinking agents may use only 1 type, and may use two or more types together. When using two or more types of crosslinking agents together, the combination of boric acid and a borax is preferable, for example, It is preferable to make the addition ratio (molar ratio) into the range of 4: 6-9: 1, and it is 5.5: 4.5-7 It is more preferable to set it as the range of: 3, and it is most preferable to set it to 6: 4.

As a crosslinking agent liquid of the said crosslinking bath, what melt | dissolved the crosslinking agent in the solvent can be used.

As a solvent, although water can be used, for example, you may use together the organic solvent which is compatible with water further. Although the density | concentration of the crosslinking agent in the said crosslinking agent liquid is not specifically limited, It is preferable to set it as the range of 1 mass% or more and 10 mass% or less, and it is more preferable to set it as 2 mass% or more and 6 mass% or less.

You may add iodide to the crosslinking agent liquid in the said crosslinking bath in order to provide in-plane uniform characteristic to a polarizing film.

Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, titanium iodide, and the like. It is preferable to set content of the iodide in to 0.05 mass% or more and 15 mass% or less, and it is more preferable to set it as 0.5 mass% or more and 8 mass% or less.

As a combination of a crosslinking agent and iodide, the combination of boric acid and potassium iodide is preferable, It is preferable that the ratio (mass ratio) of boric acid and potassium iodide shall be in the range of 1: 0.1-1: 3.5, and it is 1: 0.5-1: 2.5 It is more preferable to set it as the range.

It is preferable to make the temperature of the crosslinking agent liquid in the said crosslinking bath normally into the range of 20 degreeC or more and 70 degrees C or less, and the immersion time of a polyvinyl alcohol-type resin film is usually any time within 1 second or more and 15 minutes or less. It is possible to, and it is preferable to set it as 5 second or more and 10 minutes or less.

In the said crosslinking process, you may extend | stretch a film in a longitudinal direction in a crosslinking bath, and it is preferable to make the accumulated total draw ratio into about 1.1 times or more and about 5.0 times or less.

In addition, as a crosslinking process, you may implement by the method of apply | coating or spraying a crosslinking agent containing solution instead of the processing method immersed in a crosslinking agent liquid similarly to a dyeing process.

(Drawing step)

An extending process is a process of extending | stretching the crosslinked polyvinyl alcohol-type resin film to the longitudinal direction so that the accumulated total draw ratio may be about 2 times or more and about 8 times or less, for example. As the stretching step, for example, a wet stretching method can be employed. In this wet stretching method, stretching is performed by applying tension in the longitudinal direction while the film is immersed in a solution stored in the stretching bath.

Although it does not specifically limit as a solution stored in an extending | stretching bath, For example, the solution which added the compound of various metal salts, iodine, boron, or zinc can be used.

As a solvent of this solution, water, ethanol or various organic solvents can be used as appropriate. Especially, it is preferable to use the solution which added 2 mass% or more and about 18 mass% or less of boric acid and / or potassium iodide, respectively. When using this boric acid and potassium iodide simultaneously, it is preferable to use the content rate (mass ratio) in the ratio of about 1: 0.1-1: 4, More preferably, it is about 1: 0.5-1: 3.

As temperature of the solution in the said stretching bath, it is preferable to set it as the range of 40 to 67 degreeC, for example, and it is more preferable to set it to 50 to 62 degreeC.

(Cleaning process)

A washing | cleaning process is a process of wash | cleaning the unnecessary residues, such as the boric acid which affixed in the process before this by passing a film through the washing bath in which washing | cleaning liquids, such as water, were stored, for example.

It is preferable to add iodide to the said water, for example, it is preferable to add sodium iodide or potassium iodide.

When potassium iodide is added to the water of a washing bath, the density | concentration becomes 0.1 mass% or more and 10 mass% or less normally, Preferably they are 3 mass% or more and 8 mass% or less.

Moreover, it is preferable to make temperature of a washing | cleaning liquid into 10 degreeC or more and 60 degrees C or less, and it is more preferable to set it as 15 degreeC or more and 40 degrees C or less.

The number of times of washing treatment, that is, the number of repetitions of lifting from the washing liquid after being immersed in the washing liquid is not particularly limited, and may be a plurality of washing treatments, and water having different kinds and concentrations of additives is stored in the plurality of washing baths. You may perform a washing | cleaning process by letting it pass.

In addition, when lifting a film from the immersion bath in each process, in order to prevent generation | occurrence | production of liquid flow, it uses methods, such as using a liquid cutting roll, such as a pinch roll conventionally well-known, or wiping off a liquid with an air knife. By this, excess moisture may be removed.

(Drying step)

The film wash | cleaned at the washing | cleaning process can be introduce | transduced into the drying apparatus 11, and it can dry by appropriately optimal methods, such as natural drying, wind drying, heat drying, and can perform the said drying process.

Among these, when performing the drying process by heat drying, it is preferable that conditions of heat drying make heating temperature into 20 degreeC or more and about 80 degrees C or less, and drying time into 1 minute or more and about 10 minutes or less.

Furthermore, it is preferable to make a drying temperature as low as possible for the purpose of preventing deterioration of a film irrespective of the said method. 60 degrees C or less is preferable and, as for a drying temperature, 45 degrees C or less is especially preferable.

(Lamination process) and (winding process)

In this embodiment, the polarizing film wound by roll shape can be obtained by performing the winding process which winds the film which passed the above process with the winding roller.

In addition, in this embodiment, you may make a winding process after performing the lamination process which suitably laminates a surface protective film etc. to the surface one side or both sides of the polarizing film dried at the drying process.

The final total draw ratio of the polarizing film thus produced is preferably a draw ratio of any one of the ranges of 5.25 times or more and 8.0 times or less with respect to the raw material film, and the draw ratio of any one of the ranges of 6.0 times and 7.0 times or less. It is more preferable that is.

The above draw ratio is preferable because a polarizing film having high polarization characteristics can be obtained if the final total draw ratio is 5.25 times or more, and generation of breakage in the film can be suppressed if it is 8.0 times or less.

(Bonding process)

Although the polarizing film can be manufactured continuously continuously by performing the above process over the full length of a raw material roll, in this embodiment, before all of these raw material rolls are supplied to an extending | stretching apparatus, poly A vinyl alcohol-based resin film (raw material film) is further extracted, and a bonding step of joining the distal end portion 1b of the new raw material film to the distal end portion 1a of the raw material roll subjected to each step in the stretching apparatus is performed.

In a bonding process, it arrange | positions so that at least one part (overlapping part) of the front-end | tip part 1a of the preceding film and the new film may overlap, for example first. 0.1 mm or more and less than 50.0 mm are preferable, and, as for the overlap width at this time, 0.5 mm or more and less than 30.0 mm are more preferable. If it is 0.1 mm or more, it is easy to overlap and arrange | position the raw material film which has a wide width with repeating high precision. If it is 0.5 mm or more, it is easier to arrange | position a raw material film superimposed. On the other hand, if it is less than 50.0 mm, the unbonded part which is not joined by the laser welding mentioned later can be made small, and the fluctuation | variation of a film can be suppressed during conveyance. If it is less than 30.0 mm, the fluctuation | variation of the film in conveyance can be suppressed more.

It is preferable to arrange | position a raw material film which has a thickness of 3 micrometers or more and 300 micrometers or less in this process. When thickness is 3 micrometers or more, the fall of mechanical strength can be suppressed, and when the thickness is 300 micrometers or less, the fall of an optical characteristic can be suppressed, and even if it is applied to an image display apparatus, thickness can be achieved.

Moreover, in this process, it is preferable to arrange | position so that a raw material film may overlap via a light absorber. Specifically, between the distal end 1a and the distal end 1b (the distal end 1a) in order to increase the light absorption of the laser beam L at the junction of the distal end 1a and the distal end 1b, and to perform welding more efficiently. ) And at least one of the surfaces of the tip 1b). That is, a raw material film is a material which permeate | transmits the laser beam L, and absorbs the laser beam L with the light absorber arrange | positioned.

Carbon black, a pigment, a dye, etc. can be used for the purpose of absorbing the laser beam to be used and generating heat, for example. It is preferable that these water absorbing agents are diluted with an organic solvent etc. and apply | coated to one side of a raw material film superimposition part by suitable apply | coating means beforehand. The absorbent may be, for example, a phthalocyanine-based absorbent, a naphthalocyanine-based absorbent, a polymethine-based absorbent, a diphenylmethane-based absorbent, a triphenylmethane-based absorbent, a quinone-based absorbent, an azo-based absorbent, a diimnium salt, water, or the like. As an absorbent in the case of using a laser beam having a wavelength of 800 nm or more and 1200 nm or less, for example, Clearweld (registered trademark) made by Gentex, USA can be used.

As a coating means, general methods, such as a dispenser, an inkjet printer, screen printing, two-fluid type, one-fluid type, an ultrasonic spray, a stamper, a coater, can be used, for example.

Next, while pressing the overlapping part of a raw material film with the glass pressing member 50, the pressing member 50 is scanned, and the laser beam L is irradiated through the pressing member 50. FIG. In this step, the laser beam L is scanned along this overlapping portion, for example, while overlapping the distal end portion 1a of the preceding film and the tip portion 1b of the new film, and pressing and scanning the pressing member 50 along the overlapping portion. And it can carry out by irradiating and making mutually compatible resin at a film interface, and forming a welding part.

In this step of irradiation, the pressing time by the pressing member 50 is 3 msec or more and 600 msec or less, preferably 5 msec or more and 500 msec or less, more preferably 20 msec or more and 150 msec or less.

If the pressurization time is less than 3 msec, the pressurization time is too short, so that the pressurization by the press member 50 is released before the joining reaction due to melting of the laser beam L is completed, and thus a sufficient joining state is hardly obtained. If the pressurization time is 5 msec or more, since the pressurizing member is opened after the joining reaction by melting is completed, a sufficient joining state can be obtained. When the pressurization time is 20 msec or more, a more sufficient bonding state can be obtained.

On the other hand, if the pressurization time exceeds 600 msec, the pressurization time is too long, causing high crystallization by heat transfer to the junction and its periphery. As a result, the junction and its periphery are high crystallized, resulting in large (e.g., For example, when 5.25 times or more) an extension load is applied, stress is concentrated at the junction and its periphery. If the pressurization time is 500 msec or less, the stress to a junction part and its peripheral part can be alleviated. If the pressurization time is 150 msec or less, the stress to a junction part and its peripheral part can be effectively alleviated.

Therefore, even when extending | stretching the joined raw material film can be suppressed by making time to press the overlap part into the said range, the fracture | rupture of a junction part can be suppressed.

Here, the said press time is a value computed from the pressing area in the state which the glass pressing member 50 stopped pressurizing, and the scanning speed of the glass pressing member 50. As shown in FIG. For example, when the cylindrical glass pressing member 50 is brought into contact with the raw material film, the area is 1 mm x 4 mm, and the scanning (rotating) speed of the pressing member 50 is 50 mm / sec. Distance 1mm) / (speed 50mm / sec) becomes a pressurization time, and it calculates by 20msec.

Since the laser beam L is irradiated through the pressing member 50, the irradiation time of the laser beam L does not exceed the pressing time by the pressing member, and is equal to the pressing time by the pressing member 50 (3 msec or more and 600 msec or less). Also good.

In this process, it is preferable to use the rotatable cylindrical or spherical pressing member 50. By using the press member 50 of such a shape, the overlapping part can be easily scanned, suppressing the curvature of the overlapping part, and the pressurization time of the overlapping part can be easily controlled.

Moreover, it is preferable to use the press member 50 which has an aperture mechanism, such as a condensing lens which can collect the laser beam L. By using such a pressing member 50, laser beam L can be irradiated with high certainty to an overlapping part.

In this step, it is preferable to use an infrared laser having a wavelength of 800 nm or more and 11000 nm or less as the laser light L to be irradiated. By irradiating such a laser beam, a bonding strength can be raised and a polyvinyl alcohol-type resin film can be bonded.

In addition, in this process, it is preferable to arrange the interphase member 40 between the raw material film and the pressing member 50. By applying the pressure by the interphase member 40 to the raw material film, the positional shift of the overlapping portion due to the scanning of the pressure member 50 can be suppressed, so that the joint can be formed stably.

In particular, when the press member 50 is cylindrical or spherical, it can suppress that it bends or shifts | deviates by pressurization and rotation of the press member 50 from the state which overlapped the raw material film 1. From this viewpoint, it is preferable to insert a rubber, a resin material with a cushion property, etc. which are excellent in light transmittance between the glass pressing member 50 and the raw material film containing a non-bonded part.

In this step, it is preferable that both tip portions do not swing during conveyance by joining sufficient regions of the tip portion of each raw material film in the overlapping portion of the old and new raw material film in terms of achieving good conveyability of the film. In view of such a viewpoint, the width of the unbonded portion at the overlapping portion of the old and new raw material film is preferably 5 mm or less, more preferably 2 mm or less, and even more preferably 0 mm (the entire surface of the overlapping portion is bonded). Do.

By performing the above process, the optical film containing the polarizing film in this embodiment can be manufactured.

Moreover, although the thickness of the polarizing film to manufacture is not specifically limited, It is preferable that they are 5 micrometers or more and 40 micrometers or less. When thickness is 5 micrometers or more, the fall of a mechanical strength can be suppressed, and when the thickness is 40 micrometers or less, a fall of an optical characteristic can be suppressed, and even if it is applied to an image display apparatus, thickness can be achieved.

Since the optical film manufactured in this way can raise the bonding strength of a junction part, even when a swelling process, a dyeing process, a bridge | crosslinking process, an extending process, a washing process, a drying process, and a lamination process can be performed, the fracture | rupture at a junction can be suppressed. For this reason, extending | stretching at a high magnification (for example, 5.25 times or more) can be performed, suppressing the problem of break | rupture. Therefore, the deflection film which provided the high deflection function can be manufactured. Moreover, since it can continuously notify, without changing extending | stretching conditions, such as lowering a draw load, when passing through the junction part of the raw material film 1, the joining method of this embodiment improves work efficiency, improves productivity, and improves yield. And the effect of reducing material loss.

Therefore, the polarizing film manufactured by this embodiment can be used as a polarizing film etc. laminated | stacked on a liquid crystal cell board | substrate, etc., It can be used for a liquid crystal display device, etc. Moreover, besides a liquid crystal display device, an electroluminescent display device, a plasma display, a field emission display, etc. It can be used as a polarizing film in various image display apparatuses.

In addition, in practical use, various optical layers may be laminated on both surfaces or one side to form an optical film, or various surface treatments may be used for image display devices such as liquid crystal displays.

The optical layer is not particularly limited as long as it satisfies the required optical properties. For example, a transparent protective layer for protecting a polarizing film, an alignment liquid crystal layer for visual compensation, or the like for laminating another film In addition to the adhesive layer, an image display device such as a polarization conversion element, a reflection plate, a semi-transmissive plate, a retardation plate (including a wave plate (λ plate) such as 1/2 or 1/4), a vision compensation film, a brightness enhancement film, and the like The film used for formation of can be used.

As the surface treatment, a surface treatment for the purpose of hard coat treatment, antireflection treatment, sticking prevention, diffusion prevention, or antiglare is mentioned.

In addition, although the manufacturing method of the polarizing film in this embodiment is as above, this invention is not limited to this embodiment, Design can be changed suitably within the range which this invention intends.

In addition, in this embodiment, although the example regarding the polyvinyl alcohol-type resin film used for manufacture of a polarizing film as a resin member is given, the resin member of this invention is not limited to a polyvinyl alcohol-type resin film, It is preferable that it is a thermoplastic resin. Do. As the thermoplastic resin, for example, polycarbonate, polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, thermoplastic polyimide, triacetyl cellulose, polymethyl methacrylate, cycloolefin polymer, norbornene resin, polyoxymethylene , Polyether ether ketone, polyetherimide, polyamideimide, polybutadiene, polyurethane, polystyrene, polymethylpentene, polyamide, polyacetal, polybutylene terephthalate, ethylene vinyl acetate and the like can be used. A single layer or multiple layers may be sufficient as these resin members, and if at least 1 layer is comprised from a thermoplastic resin, it will not specifically limit.

[Example]

Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.

(Default condition)

Raw material film:

Polyvinyl alcohol resin film (Kuraray Co., Ltd. thickness, 75 micrometers, width 50mm, water absorption 6%)

· Polymerization Width:

1.8mm width

Glass pressing member:

Cylindrical shape (diameter 10 mm, roll width 15 mm)

Interphase member:

Urethane rubber (thickness 10mm, hardness 90 degrees)

Laser light:

Semiconductor laser (wavelength 940 nm, power 140 W, beam shape 4 mm x 0.6 mm (line beam), power density 5833 W / cm 2, scanning speed 100 mm / sec, integrated dose 35 J / cm 2)

Light absorbers:

Clearweld LD120C (registered trademark) (manufactured by Gentex, solvent acetone)

5 mm wide, scanning speed 200 mm / sec, 0.4 L / min

Pressure area:

1.8mm width * 3mm (3mm is the length of the scanning direction)

· Pressure size:

Pressurized to 128kgf / ㎠

Pressure time:

30msec as the 3mm length is pressed at a scanning speed of 100mm / sec

(Example 1)

The superimposition of the old and new raw material films was bonded under the above basic conditions, and the resulting bonded body in the stretching apparatus as shown in Fig. 1 had a draw ratio of 2.6 times in the swelling bath, 3.4 times in the dyeing bath, 3.6 times in the crosslinking bath, stretching bath and When the polarizing film was batch-manufactured, extending | stretching so that it might become 6.0 times in the washing | cleaning bath, the polarizing film was able to be manufactured without breaking in a junction part.

(Example 2)

Except for making the laser power 230W and scanning speed 600mm / sec (pressing time 5msec), except for bonding old and new raw material films on the said basic conditions, and extending | stretching 5.5 times in an extending | stretching bath and a washing bath. When polarizing film batch manufacture was performed on the conditions of 1, the polarizing film was able to be manufactured without breaking in a junction part.

(Example 3)

When joining a new and old raw material film on the said basic conditions except having made laser power 120W and scanning speed 30 mm / sec (pressing time 100msec), and manufacturing polarizing film batch on the conditions of Example 1, the junction part The polarizing film could be manufactured without breaking in.

(Example 4)

Except for making the laser power 40W and scanning speed 6mm / sec (pressing time 500msec), except for making old and new raw material film bond on the said basic conditions, and extending | stretching 5.25 times in extending | stretching bath and washing bath. When the polarizing film batch manufacture was performed on the conditions of 1, the polarizing film was able to be manufactured without breaking in a connection part.

(Example 5)

Except changing the film width to 2600 mm width, the old and new raw material film was bonded on the said basic conditions, the raw material film bonded by the polarizing film manufacturing apparatus shown in FIG. 1 is thrown in, and it rolls on the extending conditions of Example 1 When the polarizing film manufacture in the two rolls was performed, breakage did not generate | occur | produce in a junction part and the polarizing film was able to be manufactured continuously.

(Comparative Example 1)

Except for making the laser power 20W and scanning speed 4mm / sec (pressing time 750msec), except the case where the old and new raw material film was bonded on the said basic conditions, and extending | stretching 5.25 times in an extending | stretching bath and a washing bath. When polarizing film batch manufacture was performed on condition of 1, breakage generate | occur | produced in the connection part in the extending | stretching bath, and the polarizing film was not able to be manufactured.

(Comparative Example 2)

Except that the laser power was 500 W and the scanning speed was 1200 mm / sec (pressing time: 2.5 msec), the old and new raw material films were intended to be bonded under the above basic conditions, but good bonding was not obtained.

As described above, according to the present embodiment, it is confirmed that the breakage at the bonding portion is suppressed in the bonding of the polyvinyl alcohol-based resin film as the resin member by irradiating a laser beam with the pressing time of the pressing member being 3 msec or more and 600 msec or less. Could.

As mentioned above, although embodiment and Example of this invention were described, combining the characteristic of embodiment and an Example suitably is planned from the beginning. In addition, it should be thought that embodiment and Example which were disclosed this time are an illustration and restrictive at no points. The scope of the present invention is shown not by the above embodiments and examples but by the claims, and is intended to include all modifications within the meaning and range equivalent to the claims.

1: film
1a: distal end
1b: tip
3: supply unit
4: immersion bath
4a: swelling bath
4b: dyeing bath
4c: crosslinking bath
4d: stretch bath
4f: washing bath
9: roller
9a: nip roller
10: winding part
11: drying device
12: film for lamination
40: interphase member
50: pressing member
60: laser irradiation unit
L: laser light

Claims (6)

Arranging a plurality of resin members so that at least part of them overlap,
Scanning the pressing member while pressing the overlapping portion with a glass pressing member, and irradiating a laser beam to the overlapping portion through the pressing member;
In the step of irradiating, the pressing time by said pressing member is 3 msec or more and 600 msec or less, The joining method of the resin member characterized by the above-mentioned. The method of joining a resin member according to claim 1, wherein in the step of irradiating, a pressing member having a rotatable cylindrical shape or a spherical shape is used. The bonding method of the resin member of Claim 1 or 2 which arrange | positions so that the said overlapping part may overlap through a light absorber at the said process of arrange | positioning. The bonding method of the resin member of Claim 1 or 2 which irradiates an infrared laser of the wavelength of 800 nm or more and 11000 nm or less in the said irradiating process. The said resin member which has a thickness of 3 micrometers or more and 300 micrometers or less is used at the said process to arrange | position, The joining method of the resin member of Claim 1 or 2 characterized by the above-mentioned. The bonding method of the resin member of Claim 1 or 2 characterized by using the polyvinyl alcohol-type resin film as said resin member in the said process to arrange | position.

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