KR101723116B1 - Method of stretching polymer web and method of producing polymer film - Google Patents

Abstract

The offline draw facility has a compartment and a tenter. The storage chamber houses the preceding film roll and the subsequent film roll. The tenter widens the width of the preceding film while grasping the grip area of the preceding film delivered from the preceding film roll. After all preceding films have been dispensed, the subsequent film is dispensed from the subsequent film rolls into a tenter. In the junction portion provided in front of the tenter, the overlapping portion is provided by overlapping the rear end portion of the preceding film and the leading end portion of the following film. And a welded area is set at a portion of the overlapped portion that is away from the grip area toward the center side of the direction B. [ The bonding portion performs the bonding treatment in the welding area. The film bonded by the bonding treatment is fed to the tenter portion, and is stretched to both sides in the direction B while holding the gripping area.

Description

METHOD OF STRETCHING POLYMER WEB AND METHOD OF PRODUCING POLYMER FILM < RTI ID = 0.0 >

The present invention relates to a method of stretching a polymer web and a method of producing a polymer film.

A polymer film (hereinafter referred to as a film) has characteristics such as excellent light transmittance, flexibility, and light weight. In this respect, the film is used in many fields as an optical film. Among them, a TAC film formed of cellulose acylate, particularly cellulose triacetate having an average degree of acetylation of 57.5% to 62.5% (hereinafter referred to as TAC), is used as a protective film of a polarizing plate of a liquid crystal display device, . As the optical compensation film, for example, there is a viewing angle enlarging film.

As a main production method of a film, a solution film-forming method is known. In the solution film-forming method, a flexible film is formed on a support on which a polymer solution containing a polymer and a solvent (hereinafter referred to as " dope ") runs. This process is hereinafter referred to as a fusing process. The flexible film having the self-supporting property is peeled from the support to form a film. This process is hereinafter referred to as a pickling process. Then, the dried film is dried. This process is hereinafter referred to as a drying process. In the case of removing wrinkles, looseness, and the like generated on the film, or when imparting desired optical characteristics to the film, the film is stretched in the transverse direction while being transported at a predetermined transporting speed by using a stretching device such as a clip tenter (Hereinafter referred to as stretching treatment) is carried out in the drying step. Finally, the film is rolled into a film roll by winding using a winder or the like. Then, the film can be continuously and efficiently produced by continuously performing the fusing step, the pickling step and the drying step.

2. Description of the Related Art In recent years, demand for optical films such as TAC films has been increasing due to rapid development and dissemination of liquid crystal displays and the like. With this increase in demand, it is desired to improve the productivity of the optical film. From such a background, in many cases, a solution casting method of a cooling gelling method capable of expressing self-supporting property in a flexible film in a short time by cooling while improving the running speed of a support is often adopted as a production method of an optical film.

However, the traveling speed of the support and the transporting speed of the film in the stretching apparatus differ from each other at the optimum speed. Particularly, when the cooling gelling method is employed, the film-forming speed of the solution film-forming method is controlled by the delivery speed of the stretching device. Therefore, the production efficiency can not be substantially improved. Thus, as disclosed in Japanese Patent Application Laid-Open No. 2008-238682, a solution casting facility for producing a film without stretching treatment and a separate stretching facility (hereinafter referred to as an offline stretching facility) for performing stretching treatment on the produced film are installed separately , And a method of using these facilities together has been proposed.

Further, as described in Japanese Patent Application Laid-Open No. 2008-238682, it is preferable that the film drawn out from the core is subjected to the stretching treatment continuously in the off-line stretching facility. Here, at the time of switching the film roll, the joining of the rear end portion and the front end portion (hereinafter referred to as joining treatment) is performed in the overlapping portion where the rear end portion of the film fed out from the core and the front end portion of the new film overlap. By performing such joining treatment in the off-line stretching equipment, it is possible to continuously perform the film stretching process while switching the film roll.

However, as described in Japanese Patent Application Laid-Open No. 2008-238682, when the joining treatment is performed in the same way throughout the overlapping portion, the portion constituting the overlapping portion in the film is stretched more than the portion not constituting the overlapping portion in the film . Therefore, when the film subjected to the bonding treatment is subjected to the stretching treatment, many breakdowns occur in the vicinity of the boundary between the two portions, in which the film is broken due to the difference in the amount of deformation.

The present invention solves the above-mentioned problems, and an object of the present invention is to provide a method of stretching a polymer web and a method of producing a polymer film, which can efficiently perform film stretching treatment.

The method of stretching a polymer web of the present invention comprises a bonding step and a stretching step. The bonding step deposits the overlapping portions of the first polymer web and the second polymer web to produce a series of bonded webs. The first polymer web precedes and the second polymer web follows the first web. The overlapping portion is a portion in which the lengthwise rear end of the first polymer web overlaps the lengthwise end of the second polymer web. The overlapping portion is divided into a plurality of areas. The welding is performed in the remaining areas except for at least one of the plurality of areas. The stretching step stretches the bonded web. The stretching is performed by using a pair of holding members in a state of holding the bonded web. The overlapping portion is divided into the plurality of areas in the stretching direction.

It is preferable to perform welding at a portion apart from the grip portion gripped by the pair of gripper members.

It is preferable to perform welding at a plurality of locations in the area.

It is preferable that the length of the welded area in the stretching direction is 0.5 times or more and 0.9 times or less of the length (W) of the overlapping portion.

Wherein one of the pair of gripping means grips one end of the bonded web and the other of the pair of gripping means grips the other end of the bonded web, The width direction of the bonded web.

It is preferable that the welding is performed at a portion of the grip portion gripped by the gripping member and distanced from the gripping portion toward the center of the overlapping portion in the stretching direction.

The method of producing a polymer film of the present invention comprises a first polymer web forming step, a second polymer web forming step, a first polymer web running step, a second polymer web running step, a bonding step and a stretching step.

The first polymer web forming step produces a first polymer web. The second polymer web forming step produces a second polymer web. The first polymer web travel step travels through the first polymer web. The second polymer web travel step runs the second polymer web followed by the second polymer web. The bonding step deposits the overlapping portions of the first polymer web and the second polymer web to produce a series of bonded webs. The overlapping portion is a portion in which the lengthwise rear end of the first polymer web overlaps the lengthwise end of the second polymer web. The overlapping portion is divided into a plurality of areas. The welding is performed in the remaining areas except for at least one of the plurality of areas. The stretching step stretches the bonded web to form the polymer film. The stretching is performed by using a pair of holding members in a state of holding the bonded web. The overlapping portion is divided into the plurality of areas in the stretching direction.

One of the pair of gripping means grips one end of the joint web, the other of the pair of gripping means grips the other end of the joint web, and the stretching direction is the width of the joint web Direction.

It is preferable that the welding is performed at a portion of the grip portion gripped by the gripping member, the gripping portion being away from the gripping portion toward the center of the overlapping portion in the stretching direction.

According to the present invention, the overlapping portion is divided into a plurality of areas in the stretching direction. The bonding step is performed in the remaining areas excluding at least one of the plurality of areas. The overlapped portion subjected to such bonding treatment is liable to be entirely stretched in the width direction as compared with the overlapped portion which is subjected to the same bonding treatment throughout the whole area. Therefore, even if the film subjected to the bonding treatment as described above is stretched in the width direction, it is possible to reduce the difference in the amount of deformation between the overlapped portion and the portion other than the overlap portion, and as a result, the film can be prevented from being broken. Therefore, according to the present invention, it is possible to efficiently perform the drawing process in the offline drawing equipment. Therefore, the polymer film can be efficiently produced.

The above objects and advantages will be easily understood by those skilled in the art by reading the detailed description of the preferred embodiments with reference to the accompanying drawings.
1 is a schematic side view showing an off-line stretching facility.
2 is a plan view showing the tenter portion.
3 is a cross-sectional view of the tenter portion when the flapper is in the grip-open position;
4 is a cross-sectional view of the tenter portion when the flapper is in the gripping position.
5 is a perspective view showing an outline of the joint.
Fig. 6 is a plan view partially enlarging the receiving surface of the pedestal. Fig.
7 is a top view showing an outline of a first welding area provided in the overlapping portion;
8 is an explanatory diagram showing an outline of a first arrangement pattern of a welded portion provided in a welding area.
Fig. 9 is an explanatory view showing an outline of a second arrangement pattern of a welded portion provided in a welding area;
10 is a top view showing an outline of a second welded area provided in the overlapping portion;
11 is a top view showing an outline of a third welding area provided in the overlapping portion.
12 is a top view showing an outline of a fourth welded area provided in the overlapping portion.
13 is a top view showing an outline of a fifth welded area provided in the overlapping portion.
14 is an explanatory diagram showing an outline of a solution film-forming apparatus.
15 is an explanatory diagram showing an outline of a melt film-forming apparatus.
16 is a perspective view showing the arrangement of a plurality of rolls in the heat treatment zone.
17 is an explanatory diagram showing the roll wrap length (D) and the inter-roll length (G) of a plurality of rolls in the heat treatment zone.

1, the off-line stretching facility 2 includes a film storage chamber 4, a reservoir 5, a tenter portion 6, a thermal relaxation chamber 7, a cooling chamber 8, and a film winding chamber 9 ). The film storage chamber 4 accommodates the elongated film 3. In the tenter portion 6, the film 3 is continuously subjected to stretching treatment.

The film storage chamber 4 is provided with a turret type film delivery portion 10 and a bonding portion 11. The film delivery portion 10 has a turret arm 13. At both end portions of the turret arm 13, a pair of attachment shafts 12a are provided. The turret arm 13 is rotated 180 degrees so that one of the attachment shafts 12a is set in the film feed position 16 and the other attachment shaft 12a is set in the winding position 17 . The film roll 14 is attached to the attachment shaft 12a at the core exchange position 17 and the film roll 14 attached to the attachment shaft 12a by the rotation of the turret arm 13 is moved to the film delivery position 16 . From the attachment shaft 12a in the core exchange position 17, a hollow winding is drawn out and a new film roll 15 is set.

The film feeding section 10 feeds a film (hereinafter referred to as a preceding film) from the film roll 14 in the film feeding position 16 to the joining section 11. When the film delivery portion 10 detects that the film roll 14 set in the film delivery position 16 is missing, the turret arm 13 is rotated 180 degrees to move the new film roll 15 To the film delivery position 16. Then, a film (hereinafter referred to as a succeeding film) is fed from the new film roll 15 to the joining portion 11.

In the joining portion 11, the rear end portion of the preceding film and the leading end portion of the succeeding film are welded together to form a single film 3. The film 3 is fed to the tenter portion 6 through the reservoir 5 and stretched in the tenter portion 6. Details of the bonding portion 11 and bonding treatment will be described later.

In the reservoir 5, a part of the preceding film is allowed to remain. The length of the preceding film held in the reservoir 5 is set to be not less than the product of the time required for the bonding treatment and the conveying speed of the preceding film in the tenter portion 6. [

The tenter portion 6 grasps both side edges of the film 3 to stretch the film 3 in the width direction and feeds the film 3 to the ear cutting device 21. The die cutting device 21 cuts out both side edges of the film 3. The film 3 as a product part cut off at both side edges thereof by the knitting machine 21 is sent out to the thermal relaxation chamber 7. [ On the other hand, both side edge portions cut out from the film 3 are sent to the cut blower 22 and are finely cut into small pieces. The cut small pieces of ear pieces are sent to the crusher 23 by a wind-up device (not shown), and are crushed into chips. This chip is reused for dope preparation.

The thermal relaxation chamber 7 is provided with a plurality of rollers 25 and a drying duct not shown and the film 3 is conveyed into the thermal relaxation chamber 7 by the roller 25, And is sent to the cooling chamber 8. Further, it is preferable that the temperature of the wind from the dry air duct is not less than 20 ° C and not more than 250 ° C.

The film 3 after heat relaxation is cooled in the cooling chamber 8 to 30 占 폚 or lower and then sent to the film winding chamber 9. The film winding chamber 9 is provided with a winder 27 having a press roller 26. The film 3 is wound on the winding core 28 while being pressed against the winding core 28 by the press roller 26. [

(Tenter part)

2, the tenter portion 6 applies tension to the film 3 in the width direction (hereinafter referred to as direction B) while conveying the film 3 in the longitudinal direction, The width W1 is widened to W2. A preheating area 6a, a stretched area 6b and a relaxation area 6c are sequentially provided from the upstream side of the transport direction (hereinafter referred to as direction A) of the film 3 in the tenter part 6. A duct (not shown) is provided in each of the areas 6a to 6c. Each duct blows a predetermined drying air to the film 3 in each of the areas 6a to 6c. Thereby, the temperature of the film 3 in each of the areas 6a to 6c is adjusted to be in the optimum range.

The tenter portion 6 is provided with a clip 31, rails 32 and 33, and chains 34 and 35. The rails 32 and 33 are provided on both sides of the conveying path of the film 3, and the rails 32 and 33 are arranged so as to be spaced apart from each other by a predetermined rail interval. The rail spacing is constant in the preheating area 6a, gradually widening toward the direction A in the stretched area 6b, and constant in the relaxation area 6c. A driven sprocket 38 is provided in the vicinity of the downstream end of the rails 32 and 33 in the direction A and a driven sprocket 39 is provided in the vicinity of the upstream end of the rails 32 and 33 in the direction A.

2, the chains 34 and 35 are movably attached along the rails 32 and 33 between the driven sprocket 38 and the driven sprocket 39. As shown in Fig. A plurality of clips (31) are attached to the chains (34, 35) at predetermined intervals. 2, only a part of the clip 31 is shown in order to avoid duplication of the drawings.

3 and 4, the clip 31 is composed of a clip body 40 and a rail attachment portion 41. The clip body (40) is composed of a frame (42) and a flapper (43). The frame 42 has a substantially U-shape. The flapper 43 is rotatably attached to the frame 42 by an attachment shaft 42a. The flapper 43 is provided so as to be displaceable between a gripping-open position (see Fig. 3) in an inclined upright position and a grip position (see Fig. 4) And is biased to be in the grip position by a spring.

The rail attachment portion 41 is composed of an attachment frame 44 and a guide roller 45. The attachment frame 44 may be attached with a chain 34 or a chain 35. The guide roller 45 rotates while contacting each of the support surfaces of the sprockets 38 and 39 (see Fig. 2) or the support surface of the rail 32 or the rail 33. Thereby, the clip body 40 is guided along the rails 32, 33 without falling off the sprockets 38, 39 or the respective rails 32, 33.

Near the upstream end in the direction A of the rails 32 and 33, a gripping start position Pi is provided as shown in Fig. Further, a grip releasing position Po is provided in the vicinity of the downstream end in the direction A of the rails 32, 33. The opening member 48 of the clip 31 is located on the upstream side of the direction A of the gripping start position Pi and the opening member 49 of the clip 31 is located on the downstream side of the direction A of the gripping position Po Is installed. The opening members 48 and 49 are engaged with the engaging head 46 of the flapper 43 of the clip 31 passing near the upstream side of the direction A of the gripping start position Pi and the vicinity of the downstream side of the direction A of the grip releasing position Po, (43a).

When the engaging head 43a contacts the opening member 48 by the running of the clip 31 along the rails 32 and 33, the flapper 43 is displaced to the gripping open position (see Fig. 3). As a result, the clip 31 becomes able to accommodate the side edge portion of the film 3. Then, when the running clip 31 passes the gripping start position Pi, the contact between the opening member 48 and the engaging head 43a is released and the flapper 43 is displaced to the gripping position (see Fig. 4) . In this way, at the gripping start position Pi, the clip 31 is gripped by the film gripping surface 42b and the flapping lower surface 43b at both side edge portions (hereinafter referred to as gripping area) 3w of the film 3, . Thereafter, the film 3 is sequentially transported to the respective areas 6a to 6c in a state in which the holding area 3w is gripped by the clip 31. Then, In the stretched area 6b, stretching process is performed in which the film 3 is stretched in the direction B and the width of the film 3 is widened from W1 to W2. The elongation ratio ER (= W2 / W1) is preferably 1.1 or more and 2.0 or less. Thereafter, when the clip 31 passes the grip releasing position Po, the engaging head 43a is brought into contact with the opening member 49. Then, By the contact of the opening member 49 and the engaging head 43a, the flapper 43 is displaced to the gripping open position. Thus, the clip 31 opens the grip of the grip area 3w.

(Bonding unit)

1 and 5, the nip roller 51 and the nip roller 52 are disposed on the upstream side of the direction A in the joining portion 11, and between the nip roller 51 and the nip roller 52 The ultrasonic bonding device 53 and the pedestal 54 are disposed.

(Base)

The pedestal 54 has a receiving surface 55. As shown in Fig. 6, the receiving surface 55 is subjected to a roulette process so that the projections 56 are formed in an infinite number of times. The protrusions 56 are formed as squares. The shape of the projection 56 is not limited to a square, and may be a shape such as a truncated cone, a circle, a pyramid, a cone, or other shapes. Further, the pedestal 54 is movably provided in the direction C under the control of a control unit (not shown).

(Nip roller)

In Fig. 1, the nip rollers 51 and 52 perform a polymerization process under the control of a control unit (not shown). In the polymerization process, the nip rollers 51 and 52 sandwich the preceding film 3a and the succeeding film 3b to feed the films 3a and 3b in the direction opposite to the direction A or the direction A, The position of the rear end 3ax and the position of the front end 3bx of the subsequent film 3b are adjusted to be on the receiving face 55 as shown in Fig. The overlapping portion 60 in which the rear end portion 3ax of the preceding film 3a and the front end portion 3bx of the succeeding film 3b overlap is formed on the receiving surface 55. [

(Ultrasonic bonding apparatus)

The ultrasonic bonding apparatus 53 is for welding the target using frictional heat due to mechanical vibration and includes a vibrator 65, a horn 66, and an oscillator 67. Under the control of a control unit (not shown), the oscillator 67 mechanically vibrates the vibrator 65 at a predetermined frequency (10 kHz to 50 kHz). The horn 66 vibrates in the thickness direction of the film 3 (hereinafter referred to as direction C) as a result of resonance with the vibration of the vibrator 65.

The ultrasonic bonding device 53 is attached to the pressing portion 71 through the attachment member 70. [ The pressing portion 71 makes the ultrasonic bonding device 53 movable in the direction C under the control of the control portion.

Further, the pressing portion 71 is provided in the first slide mechanism 72 so as to be movable in the A direction. Further, the first slide mechanism 72 is installed in the second slide mechanism 73 so as to be movable in the direction B. The second slide mechanism 73 includes a pair of pulleys 76 that are rotatably installed, a belt 77 that extends over the pair of pulleys 76, and a belt 77 that rotates the pulley 76 by a predetermined amount in a predetermined direction And a control unit (not shown). In this way, the ultrasonic bonding apparatus 53 is movable in the directions A and B by the first slide mechanism 72 and the second slide mechanism 73.

The ultrasonic bonding device 53 and the pedestal 54 can be moved between a nipping position where the overlapping portion 60 is held at a predetermined pressure and a retreat position where the overlapping portion 60 is retracted from the nipping position under the control of the control portion. When the joining step is not performed, the ultrasonic joining apparatus 53 and the pedestal 54 are in the retreat position and move to the gripping position only when the joining step is performed.

Next, the joining process performed in the joining portion 11 will be described. 1 and 5, the film feeder 10 feeds the preceding film 3a from the film roll 14 to the joining portion 11 and the nip rollers 51 and 52 feed the preceding film 3a, To the reservoir (5). Thereafter, when the control unit detects that the film roll set in the film feed position 16 is missing, the film feeder 10 rotates the turret arm 13 by 180 degrees to produce a new film roll (15) to the film delivery position (16). Then, the succeeding film 3b is sent out from the new film roll 15.

The nip rollers 51 and 52 align the rear end portion 3ax and the front end portion 3bx by transporting the preceding film 3a and the following film 3b. The overlapping portion 60 in which the rear end portion 3ax of the preceding film 3a and the front end portion 3bx of the succeeding film 3b overlap is formed on the receiving surface 55. [

The ultrasonic bonding apparatus 53 and the pedestal 54 are set in advance in the retracted position. The first slide mechanism 72 and the second slide mechanism 73 set the ultrasonic bonding apparatus 53 at a predetermined position on the reception surface 55 on the basis of a predetermined welding area in the overlapping portion 60. [

Thereafter, when the ultrasonic bonding apparatus 53 and the pedestal 54 in the retracted position are moved to the nipping position by the control unit, the overlapping portion 60 is held by the vibrating horn 66 and the receiving surface 55 , The overlapping portion 60 is vibrated. As a result of the frictional heat being generated between the rear end portion 3ax of the preceding film 3a and the front end portion 3bx of the following film 3b due to the vibration of the overlapping portion 60, the vibrating horn 66 and the receiving face 55 and the rear end portion 3ax and the distal end portion 3bx in the vicinity thereof are welded together.

In addition, the first slide mechanism 72 and the second slide mechanism 73 move the ultrasonic bonding apparatus 53 in the direction B or A in the welded area. As a result, the horn 66 comes into contact with the entire overlapping portion 60 in the welding area, and welding of the rear end portion 3ax and the front end portion 3bx in the entire welding region is completed.

The pressing portion 71 moves the ultrasonic bonding device 53 and the pedestal 54 to the retreat position after welding of the rear end portion 3ax and the front end portion 3bx is completed in the entire welding region. As described above, the joining portion 11 can weld the rear end portion 3ax and the distal end portion 3bx in a desired welding area in the overlapping portion 60. [

In the present invention, as shown in Fig. 7, a welded area 60y is set at a portion of the overlapping portion 60 that is distant from the gripping area 3w toward the center of the direction B, and the welded area 60y is set at both sides in the direction B of the welded area 60y. The area 60z is set and the joining process is performed in the welding area 60y. Even if the film 3 subjected to the bonding treatment is subjected to the stretching treatment, the untreated area 60z between the holding area 3w and the welding area 60y is the same as the film 3 which does not form the overlapping part 60 .

Therefore, according to the present invention, it becomes possible to reduce the difference between the amount of deformation of the entire overlapped portion 60 and the amount of deformation of the portion of the film 3 that does not form the overlapping portion 60 in the stretching process, It is possible to suppress the breakage of the film 3 caused by the difference in the amount of deformation between the two.

The distance CL1 between the gripping area 3w and the welded area 60y in the direction B is preferably not less than 0.05 times and not more than 0.25 times the width W1 of the film 3 and is preferably not less than 50 mm and not more than 600 mm, desirable. The length Wy in the direction B of the welding area 60y is preferably 0.5 times or more and 0.9 times or less of the width W1 of the film 3 and is preferably 600 mm or more and 2200 mm or less, for example. The length L1 of the direction A of the overlapping portion 60 is preferably 10 mm or more and 40 mm or less, for example.

(Welding condition)

In the bonding treatment, the bonding temperature (W _TH ) per unit thickness is preferably 0.4 W / μm or more and 1.1 W / μm or less, more preferably 0.6 W / μm or more and 0.9 W / μm or less. Bonding work (W _TH) welding of 0.4W / ㎛ above is 0.4W / ㎛ if less apt to be delivered to a sufficient overlapping parts vibration 60 to the weld compared to, after the end result (3ax) and distal end (3bx) Can be performed more reliably. Bonding work (W _TH), because when the vibration of the overlapping portion 60 as compared to the case is greater than 1.1W / ㎛ is less than 1.1W / ㎛ too large, it is possible to prevent the resulting fracture. The bonding date W _TH per unit thickness is obtained by dividing the amount W of the horn 66 given to the overlapping portion 60 by the thickness of one film 3.

In the bonding treatment, the pressure per unit thickness P _TH applied to the overlapping portion 60 is preferably 1.0 x 10 ^-3 MPa / 탆 or more and 3.5 x 10 ^-3 MPa / 탆 or less. When the pressure per unit thickness (P _TH ) is 1.0 × 10 ^-3 MPa / μm or more, vibrations sufficient for welding are liable to be transmitted to the overlapping portion 60 as compared with the case of less than 1.0 × 10 ^-3 MPa / μm The welding of the end portion 3ax and the tip end portion 3bx can be more reliably performed. On the other hand, when the pressure per unit thickness (P _TH ) is 3.5 × 10 ^-3 MPa / μm or less, the vibration of the overlapping portion 60 does not become excessively large as compared with the case where it is larger than 3.5 × 10 ^-3 MPa / The resultant breakage can be prevented. The pressure P _TH per unit thickness is the pressure P given by the horn 66 to the overlapping portion 60 divided by the thickness of one film 3.

It is preferable that the horn amplitude (f _TH ) per unit thickness in the above fusion welding is 0.35 or more and 0.7 or less. If the horn amplitude f _TH per unit thickness is 0.35 or more, vibration sufficient for welding is likely to be transmitted to the overlapping portion 60 as compared with the case where the horn amplitude f _TH is less than 0.35. As a result, So that it can be performed surely. On the other hand, when the horn amplitude f _TH per unit thickness is 0.7 or less, the vibration of the overlapping portion 60 does not become excessively large as compared with the case where the horn amplitude per unit thickness is larger than 0.7, and as a result, breakage can be prevented. The horn amplitude (f _TH ) per unit thickness is the amplitude (f) of the horn (66) divided by the thickness of one film (3).

It is preferable that the total area of the areas where the rear end 3ax and the tip end 3bx are welded is 2000 mm < 2 >

(film)

The width W1 of the film 3 is preferably 600 mm or more, more preferably 1300 mm or more and 2500 mm or less, and the effect of the present invention is exhibited even when it is greater than 2500 mm. The thickness (TH1) of the film (3) is preferably 20 mu m or more and 200 mu m or less, more preferably 30 mu m or more and 100 mu m or less.

(Welding pattern)

The arrangement pattern of the welded portion in the welded area 60y is a solid pattern (not shown) provided with a welded portion without gaps throughout the welded area 60y, a plurality of welded portions provided in the welded area 60y as shown in FIG. 8 It is also possible to use a pattern in which the welded portion 81 provided in the welded area 60y as shown in Fig. 9 is provided as a wire rope in addition to the pattern in which the welded portion 80 is arranged as shown in Fig. Although the filament pattern shown in Fig. 9 is provided so as to be stretched in the direction B, it may be provided to be stretched in the direction A, or may be provided to stretch in a direction intersecting the direction A or the direction B at an acute angle. The number of the ancillary patterns shown in Fig. 9 may be not only two but also three or more.

In the above embodiment, the welded area 60y is set at the central portion in the direction B. [ However, the present invention is not limited to this. As shown in Fig. 10, a welded area 60y may be set at a portion on both end sides of the direction B rather than a pair of grip areas 3w and a pair of grip areas 3w It is also good.

(Welded area)

In the above embodiment, the welded area 60y is set at a portion CL1 away from the grip area 3w to the center side in the direction B. However, the present invention is not limited to this. For example, the welded area 60y may be set in a part of the overlapping portion 60 so that the overlapping portion 60 can be stretched in the direction B as a whole in the stretching process.

As an example of the setting of the welding area 60y, the overlapping area 60 is divided into n areas (n is a natural number of 2 or more) in the direction B, and even if many (n-1) areas are set as the welding area 60y, The area may be set as the non-application area 60z. Here, it is preferable that the untreated area 60z is provided in a portion of the film constituting the overlapping portion 60 where the stretching amount in the stretching treatment is large. The stretching amount of the film 3 in the stretching process is larger than the stretching amount of the film 3 in the direction B from the grip area 3w to the center portion side in the direction B when gripping the grip area 3w and stretching the film 3 in the direction B . Therefore, when this stretching process is performed, provision of the non-application area 60z on the center side in the direction B of the grip area 3w is advantageous in that the stretching amount as the whole overlapping part 60 and the overlapping part 60 of the film 3, Is most preferable in that it reduces the difference in the stretching amount of the portion that does not constitute the nonwoven fabric.

In addition, the setting of the welded area 60y in the present invention is not limited to the form shown in Fig. 7 or Fig. As another form, there is a form in which a welding area 60y is provided at both ends of the direction B of the overlapping portion 60 as shown in Fig.

In the case where a plurality of welding areas 60y are provided in the overlapping portion 60, the length of the welding area 60y in the direction B is different depending on the position at which the welding area 60y is set as shown in Fig. 12 Maybe. That is, it is preferable that the length of the welding area 60ya provided in the portion where the stretching amount in the stretching treatment is large is shorter than the length of the welding area 60yb provided in the portion where the stretching amount in the stretching treatment is small. Likewise, it is preferable that the length of the unapplied area provided in the portion where the stretching amount in the stretching treatment is large is longer than the length of the unfixed area provided in the portion where the stretching amount in the stretching treatment is small.

In the above embodiment, the welded area 60y is set so as to be aligned in a line in the direction A in the overlapped portion 60. [ However, the present invention is not limited to this, and the welded area 60y may be set so as to be lined up in a plurality of rows in the direction A. Therefore, the present invention may provide the welding area 60y to the overlapping portion 60 as shown in Fig.

In the above embodiment, the stretching process is performed in the width direction of the film 3, but the present invention is not limited to this. In this case also, the overlapping portions 60 may be divided into a plurality of areas in the stretching direction, at least one area may be a non-application area, and the remaining areas may be a welding area.

In the above embodiment, the joining process is performed by sandwiching a predetermined portion of the overlapping portion 60 using the receiving surface 55 and the horn 66 on which the roret processing is performed, but the present invention is not limited to this. From the viewpoint of preventing breakage of the film 3, it is preferable that the portion sandwiched by the horn 66 and the receiving surface 55 is a line or point rather than a surface. As described above, the receiving surface of the pedestal 54 may be a flat surface, a flat surface formed with a linear groove, a line-shaped projection, or a receiving surface 55 shown in Fig. 6, The receiving surface 55 as shown is the best.

In the above embodiment, the joining process of the overlapping portions 60 is performed using the horn 66 vibrating in the direction C. However, the present invention is not limited to this, and the joining process may be performed in the direction crossing the direction A, the direction B, The joining treatment of the overlapping portion 60 may be performed using the vibrating horn 66. [

In the above embodiment, the bonding treatment is performed using the ultrasonic bonding apparatus 53. However, the present invention is not limited to this. The bonding treatment may be performed by bringing the heating head into contact with a predetermined welding area such as a heat sealer (Acetone or the like) is applied to a predetermined welding area of the rear end portion 3ax or the front end portion 3bx and then the rear end portion 3ax and the front end portion 3bx are polymerized to form the rear end portion 3ax and the front end portion 3bx It may be welded.

In the above embodiment, the non-application area 60z is set in the overlapping area 60. [ However, the present invention is not limited to this, and if the superposed portion 60 can be stretched in the direction B as a whole in the stretching process, the low adhesion treatment may be performed in the untreated area 60z. In the low-joint treatment, the rear end portion 3ax and the tip end portion 3bx of the overlapping portion 60 are welded together in the same manner as in the normal joining treatment. However, the degree of the welding is lower than that of the ordinary bonding treatment. The conditions of the low-temperature bonding treatment may be made smaller than those of the ordinary bonding treatment. (W _TH ) is preferably 0.1 W / μm or more and 0.4 W / μm or less when the ultrasonic joining apparatus is used, and the pressure (P _TH ) per unit thickness is preferably 0.1 × 10 ^-3 MPa / Mu m or more and 1.0 x 10 < ^-3 > MPa / mu m or less.

(Solution film-forming method)

The film (the preceding film and the following film) in the above embodiment can be obtained by a solution casting method. 14, the solution film-forming equipment 210 for performing the solution film-forming method comprises a stock tank 211, a flexible chamber 212, a pin tenter 213, a drying chamber 215, a cooling chamber 216 and a winding chamber 217 ).

The stock tank 211 has a stirring blade 211b and a jacket 211c rotated by a motor 211a. In the interior of the stock tank 211, a dope 221 in which a polymer as a raw material of the film 3 is dissolved in a solvent is stored. The dope 221 in the stock tank 211 is adjusted by the jacket 211c so that the temperature becomes substantially constant. Further, the rotation of the stirring blade 211b keeps the dope 221 at a uniform quality while suppressing aggregation of the polymer and the like. The pipe 222 connects the stock tank 211 and the flexible die 230.

The flexible chamber 212 is provided with a flexible die 230, a flexible drum 232 as a support, a peeling roller 234, temperature control devices 235 and 236 and a decompression chamber 237. The flexible drum 232 is rotated in the circumferential direction (hereinafter referred to as the direction Z1) around the shaft 232a by a driving device (not shown). The flexible drum 212 and the flexible drum 232 are set at temperatures such that the flexible film 233 is cooled and solidified (gelled) by the temperature control devices 235 and 236.

The flexible die 230 has a slit formed to be stretched in the width direction. The flexible die 230 discharges the dope 221 from the slit toward the circumferential surface 232b of the rotating flexible drum 232. Thereafter, the flexible film 233 is formed from the dope 221 on the circumferential surface 232b of the flexible drum 232. During the rotation of the flexible drum 232 about 3/4 of its rotation, the self-supporting property by gelation is expressed in the flexible film 233, and the flexible film 233 is removed from the flexible drum 232 by the peeling roller 234. [ And becomes a wet film 238. The amount of the residual solvent in the flexible film 233 at the time of dusting is preferably 150 wt% or more and 320 wt% or less. Here, the amount of residual solvent means the amount of solvent remaining on the flexible film 233, etc. on the basis of the dry weight, and a method of measuring the amount is to take a sample from a target film or the like, (Xy) / y} x 100.

The decompression chamber 237 is disposed on the upstream side of the direction Z1 with respect to the flexible die 230 and holds the inside of the decompression chamber 237 at a negative pressure so that the back surface of the flexible bead ) Is depressurized to a desired pressure. The reduced pressure on the back side of the flexible bead reduces the influence of the accompanying wind generated by the rotation of the flexible drum 232 and forms a stable flexible bead between the flexible die 230 and the flexible drum 232, A flexible film 233 with less unevenness can be formed.

The material of the flexible die 230 is formed of a material having a high corrosion resistance and a low coefficient of thermal expansion for an electrolyte aqueous solution, a mixed solution of dichloromethane and methanol, and the like. The finishing accuracy of the contact surface of the flexible die 230 is preferably 1 mu m or less in surface roughness and the straightness is 1 mu m / m or less in any direction.

The circumferential surface 232b of the flexible drum 232 is chrome plated and has sufficient corrosion resistance and strength. The temperature regulating device 236 circulates the heat transfer medium to the flexible drum 232 to maintain the temperature of the peripheral surface 232b of the flexible drum 232 at a desired temperature. The temperature of the circumferential surface 232b of the flexible drum 232 is maintained at a desired temperature by passing through the heat transfer medium flow path in the flexible drum 232. [

Although the width of the flexible drum 232 is not particularly limited, it is preferable to use the flexible drum 232 having a range of 1.1 to 2.0 times the flexible width of the dope. The material of the flexible drum 232 is preferably made of stainless steel, and more preferably made of SUS316 so as to have sufficient corrosion resistance and strength. It is preferable that the chrome plating treatment performed on the peripheral surface 232b of the flexible drum 232 is Vickers hardness Hv of 700 or more and film thickness of 2 占 퐉 or more, so-called hard chrome plating.

A condenser (condenser) 239 for condensing and liquefying the evaporating solvent is provided in the flexible chamber 212 and a recovery device 240 for recovering the condensed and liquefied solvent. The condensed liquid in the condenser 239 is recovered by the recovery device 240. The solvent is recycled as a solvent for dope preparation after being regenerated in the regenerator.

A moving part 241 and a pin tenter 213 are sequentially disposed downstream of the flexible chamber 212. In the moving unit 241, the conveying roller 242 introduces the wet film 238 into the pin tenter 213. The pin tenter 213 has a plurality of fin plates that penetrate and hold both side edges of the wet film 238, and the pin plates run on the orbit. The drying air is blown against the wet film 238 driven by the fin plate, and the wet film 238 is dried to become the film 220. [

And a cutting device 243 is provided downstream of the pin tenter 213, respectively. The splicing device 243 cuts both side edges of the film 220. The cut edge portions are sent out to the crusher 244 by blowing, crushed, and reused as raw materials such as dope.

The drying chamber 215 is provided with a plurality of rollers 247, on which the film 220 is wound and transported. The drying chamber 215 is connected to the adsorption recovery device 248 for adsorbing and recovering the evaporated solvent. A cooling chamber 216 is provided on the outlet side of the drying chamber 215. The cooling chamber 216 is cooled until the film 220 becomes room temperature. A forced static electricity removing device (static electricity removing bar) 249 is provided downstream of the cooling chamber 216, so that the film 220 is discharged. Further, on the downstream side of the forced static eliminator 249, a nulling roller 250 is provided, and knurling is applied to both side edge portions of the film 220. The winding chamber 217 is provided with a winder 251 having a press roller 252 so that the film 220 is wound in a roll on the winding and the winding roll 251 is obtained by the winder 251. The film rolls 255 are stored as film rolls 14 and 15 in the film storage chamber 4 (see Fig. 1) of the off-line stretching facility 2 from the winding chamber 217.

(Polymer)

Hereinafter, the polymer as a raw material of the film will be described. In the present embodiment, cellulose acylate is used as the polymer, and cellulose triacetate (TAC) is particularly preferable as the cellulose acylate. Among the cellulose acylates, it is more preferable that the substitution degree of the acyl group in the hydroxyl group of the cellulose satisfies all of the following formulas (I) to (III). In the following formulas (I) to (III), A and B represent substitution degree of an acyl group with respect to a hydrogen atom in the hydroxyl group of cellulose, A represents substitution degree of an acetyl group, 22 < / RTI > It is also preferable that 90% by weight or more of TAC is 0.1-4 mm particles. However, the polymer that can be used in the present invention is not limited to cellulose acylate.

(I) 2.5? A + B? 3.0

(II) 0? A? 3.0

(III) 0? B? 2.9

The glucose unit in which the? -1,4-linked cellulose constituting cellulose has a free hydroxyl group at 2-position, 3-position and 6-position. The cellulose acylate is a polymer (polymer) obtained by esterifying a part or all of these hydroxyl groups with an acyl group having two or more carbon atoms. The degree of acyl substitution means the ratio of esterification of the hydroxyl group of cellulose to the 2-position, 3-position and 6-position, respectively (100% esterification is referred to as substitution degree 1).

The total degree of acyl substitution, that is, the value of DS2 + DS3 + DS6 is preferably 2.00 to 3.00, more preferably 2.22 to 2.90, and particularly preferably 2.40 to 2.88. The value of DS6 / (DS2 + DS3 + DS6) is preferably 0.28 or more, more preferably 0.30 or more, particularly preferably 0.31 to 0.34. Here, DS2 is the ratio of the hydrogen at the 2-position hydroxyl group in the glucose unit replaced by the acyl group (hereinafter referred to as the 2-position acyl substitution degree), DS3 is the ratio of the hydroxyl group at the 3-position in the glucose unit (Hereinafter, referred to as acyl substitution degree at 3-position) in which hydrogen is substituted by an acyl group, and DS6 represents a ratio at which the hydrogen of the hydroxyl group at the 6-position in the glucose unit is substituted by an acyl group Quot; degree of substitution ").

The acyl group used in the cellulose acylate of the present invention may be only one type, or two or more kinds of acyl groups may be used. When two or more kinds of acyl groups are used, it is preferable that one of them is an acetyl group. The sum total of the hydroxyl groups at the 2-position, 3-position and 6-position substituted by the acetyl group is referred to as DSA, and the sum of the hydroxyl groups at the 2-position, 3-position and 6-position is substituted by an acyl group other than the acetyl group In terms of DSB, the value of DSA + DSB is preferably 2.22 to 2.90, particularly preferably 2.40 to 2.88.

The DSB is preferably 0.30 or more, and particularly preferably 0.7 or more. The DSB is preferably a substituent of the 6-position hydroxyl group of 20% or more, more preferably 25% or more, still more preferably 30% or more, and particularly preferably 33% or more. The cellulose acylate having a DSA + DSB value of at least 6, more preferably at least 0.80, especially at least 0.85 at the 6-position of the cellulose acylate is also preferable, and the use of these cellulose acylates makes it more soluble Excellent solution (dope) can be produced. In particular, when a non-chlorine-based organic solvent is used, a dope exhibiting excellent solubility, having a low viscosity and excellent in filtration can be produced. Cellulose as a raw material of cellulose acylate may be obtained from either a linter or a pulp.

The acyl group having two or more carbon atoms of the cellulose acylate in the present invention may be either an aliphatic group or an aryl group and is not particularly limited. Examples thereof include alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters and aromatic alkylcarbonyl esters of cellulose, and they may further have substituted groups. Preferable examples thereof include a propionyl group, a butanoyl group, a pentanoyl group, a hexanoyl group, an octanoyl group, a decanoyl group, a dodecanoyl group, a tridecanoyl group, a tetradecanoyl group, a hexadecanoyl group, A butanoyl group, a t-butanoyl group, a cyclohexanecarbonyl group, an oleyl group, a benzoyl group, a naphthylcarbonyl group, and a cinnamoyl group. Among them, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzyl, naphthylcarbonyl and cinnamoyl groups are more preferable, and propionyl Group, butanoyl group.

Details of the cellulose acylate are described in paragraphs [0140] to [0195] of Japanese Patent Application Laid-Open No. 2005-104148, and the description thereof can also be applied to the present invention. Also, as to additives such as solvents and plasticizers, deterioration inhibitors, ultraviolet absorbers (UV agents), optically anisotropic control agents, retardation control agents, dyes, matting agents, release agents and release promoters, 0196] to [0516], and these descriptions are also applicable to the present invention.

(menstruum)

Examples of the solvent for preparing the dope include aromatic hydrocarbons such as benzene and toluene, halogenated hydrocarbons such as dichloromethane and chlorobenzene, alcohols such as methanol, ethanol, n-propanol, n- Diethyleneglycol, etc.), ketones (e.g., acetone, methyl ethyl ketone, etc.), esters (such as methyl acetate, ethyl acetate and acetic acid), and ethers (e.g., tetrahydrofuran, methyl Cellosolve, etc.). In the present invention, it means a polymer solution or dispersion obtained by dissolving or dispersing a polymer in a solvent.

Of these, halogenated hydrocarbons having 1 to 7 carbon atoms are preferably used, and dichloromethane is most preferably used. It is preferable to mix one to several kinds of alcohols having 1 to 5 carbon atoms in addition to dichloromethane from the viewpoints of solubility of TAC, rustability of the flexible film from the support, mechanical strength of the film, and physical properties such as optical properties of the film Do. The content of the alcohol is preferably 2% by weight to 25% by weight, more preferably 5% by weight to 20% by weight based on the whole solvent. Specific examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol and the like, but methanol, ethanol, n-butanol or a mixture thereof is preferably used.

However, in recent years, studies have also been made on the solvent composition when dichloromethane is not used for the purpose of minimizing the influence on the environment. For this purpose, an ether having 4 to 12 carbon atoms, 12 individual ketones, esters having 3 to 12 carbon atoms, and alcohols having 1 to 12 carbon atoms are preferably used. They may be suitably mixed and used. For example, a mixed solvent of methyl acetate, acetone, ethanol, and n-butanol is listed. These ethers, ketones, esters and alcohols may have a cyclic structure. Further, a compound having two or more functional groups (that is, -O-, -CO-, -COO-, and -OH) of an ether, a ketone, an ester and an alcohol may be used as a solvent.

In the above-described embodiment, cellulose acylate is used as the raw material of the film. However, the present invention is not limited to these examples. The present invention is also applicable to cyclic olefins and other cellulose esters such as cellulose acetate propionate. It may also be applied to a polymer film produced by a solvent production method.

(Melt film-forming equipment)

Next, a manufacturing facility for manufacturing a polymer film by a melt film forming method (hereinafter referred to as a melt film forming facility) will be described. The melt film-forming equipment 410 is an apparatus for producing a thermoplastic film F that can be used for a liquid crystal display device or the like as shown in Fig. The pellet-shaped thermoplastic resin as the raw material of the thermoplastic film F is introduced into the dryer 412 and dried. The pellet is extruded by the extruder 414 and supplied to the filter 418 by the gear pump 416 . Subsequently, foreign matter is filtered by the filter 418, and molten resin (molten thermoplastic resin) is extruded from the die 420. The molten resin is pressed and molded by the first casting roll 428 and the touch roll 424 and then cooled and solidified in the first casting roll 428 into a film having a predetermined surface roughness, 426) and conveyed by the third casting roll 427 to obtain an unstretched film Fa. This unstretched film Fa may be wound at this stage or may be supplied to the transverse drawing section 442 which continuously performs intensional span stretching. Even when the once-wound unstretched film Fa is supplied again to the transverse elongation section 442, the same effect as that obtained when continuous stretching is applied to the transverse elongation section 442 is obtained.

In the transverse drawing 442, the unstretched film Fa is stretched in the transverse direction (hereinafter referred to as direction Y) orthogonal to the conveying direction (hereinafter referred to as direction X) to form the transverse stretched film Fb. The preheating section 436 may be provided on the upstream side of the transverse drawing section 442 or the opening and closing section 444 may be provided on the downstream side of the transverse drawing section 442. [ This makes it possible to reduce the number of bowing (misalignment of optical axes) during stretching. The preheating temperature is preferably higher than the transverse stretching temperature, and the heat setting temperature is preferably lower than the transverse stretching temperature. That is, the bowing becomes concave toward the direction of the width in the center in the width direction, but the bowing can be reduced by setting the preheating temperature> the transverse stretching temperature and the transverse stretching temperature> the heat fixing temperature. Either the preheating treatment or the heat fixing treatment may be performed, or both of them may be performed.

After the post-stretching, the post-stretched film Fb is shrunk in the heat treatment zone 446 in the X direction. In the heat treatment zone 446, as shown in Fig. 16, the rolls 448a to 448a are formed so that the shrinkage in the direction X does not occur in the direction Y while the side end portions of the transversely stretched film Fb are not held by the chuck, 448d to transport the transversely stretched film Fb. At this time, as shown in Fig. 17, the plurality of rolls 448a to 448d are arranged such that the ratio (G / D) of the roll wrap length D to the roll-to-roll length G is 0.01 or more and 3 or less. Thus, contraction in the direction Y is suppressed by the friction between the transversely stretched film Fb and the rolls 448a to 448d. The transverse stretched film Fb has a ratio V2 / V1 of the circumferential velocity V1 by the roll 448a on the upstream side to a circumferential velocity V2 by the roll 448d on the downstream side of 0.6 or more and 0.999 or less And is heat-treated. That is, the transversely stretched film Fb is shrunk in the X direction in the heat treatment zone.

The transversely stretched film Fb is heat-treated in the heat treatment zone to produce a thermoplastic film F which is the final product in which the orientation angle and the retardation are adjusted. This film (F) is wound by a winding section (449). The wound film F is rolled into a film storage chamber 4 (see Fig. 1) of the off-line stretching equipment 2 as film rolls 14 and 15.

The stretching in the direction X before or after the stretching in the direction Y may be performed. The stretching in the direction X can be achieved by transporting the film by using a plurality of nip roll pairs aligned in the direction X and by increasing the circumferential speed of the nip roll pair on the downstream side of the circumferential speed of the upstream nip roll pair. If the ratio (L / W) of the nip roll distance L in the direction X to the film width W in the nip roll pair on the upstream side is large, the stretching method is different. When the L / W is small, And a stretching method in the direction X as described in JP-A-2006-348114. Although this method tends to increase Rth, the device can be made compact. On the other hand, when the L / W is large, a stretching method of direction X as described in JP-A-2005-301225 can be used. This method can reduce the Rth, but the device is liable to be damaged.

The polymer which can be used in the melt film-forming method is not particularly limited as long as it is a thermoplastic resin, and examples thereof include cellulose acylate, lactone ring-containing polymer, cyclic olefin, polycarbonate and the like. Of those, preferred are cellulose acylate and cyclic olefin, and among these, a cellulose acylate containing an acetate group and a propionate group, a cyclic olefin obtained by addition polymerization, and more preferably a cyclic olefin obtained by addition polymerization .

(Cyclic olefin)

The cyclic olefin is preferably polymerized from a norbornene-based compound. This polymerization can be carried out by any of ring-opening polymerization and addition polymerization. Examples of the addition polymerization include those described in JP 3517471 A, JP 3559360 A, JP 3867178 A, JP 3871721 A, JP 3907908 A, JP 3945598 A, and JP 2005-527696 A Japanese Patent Application Laid-Open No. 2006-28993, and International Publication No. 2006/004376 pamphlet. Particularly preferred is that disclosed in Japanese Patent No. 3517471.

As the ring-opening polymerization, there may be mentioned, for example, pamphlet of International Publication No. 98/14499, Japanese Patent No. 3060532, Japanese Patent No. 3220478, Japanese Patent No. 3273046, Japanese Patent 3404027, Japanese Patent 3428176, Japanese Patent 3687231, Japanese Patent 3873934, and JP-A-3912159. Of these, preferred are the pamphlets of International Publication Nos. 98/14499 and 3060532.

Among these cyclic olefins, addition polymerization is more preferable.

(Lactone ring-containing polymer)

Refers to those having a lactone ring structure represented by the following formula (1).

In the general formula (1), R ¹ , R ² and R ³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.

The content of the lactone ring structure in the general formula (1) is preferably 5 to 90% by weight, more preferably 10 to 70% by weight, and still more preferably 10 to 50% by weight.

(Meth) acrylic acid ester, a hydroxyl group-containing monomer, an unsaturated carboxylic acid, and a monomer represented by the following formula (2), in addition to the lactone ring structure represented by formula (1) Structural units (repeating structural units) are preferred.

(Compound 2) of the R ⁴ represents a hydrogen atom or a methyl group, X is a hydrogen atom, a C 1 -C 20 alkyl group, an aryl group, -OAc group, -CN group, -CO-R ⁵ group, or a -COR ⁶ group , The Ac group represents an acetyl group, and R ⁵ and R ⁶ represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.

For example, Japanese Laid-Open Patent Publication No. 2006/025445, Japanese Laid-Open Patent Publication No. 2007-70607, Japanese Laid-Open Patent Publication No. 2007-63541, Japanese Laid-Open Patent Publication No. 2006-171464, Japanese Laid-Open Patent Publication No. 2005-162835 Can be used.

Claims (11)

Depositing an overlapping portion of the first polymer web and the second polymer web to form a series of bonded webs, wherein the first polymer web precedes and the second polymer web follows the first polymer web, Is a portion where the longitudinal end of the first polymer web overlaps with the longitudinal end of the second polymer web, and the overlapping portion is divided into a plurality of areas, and the welding is performed by one or more of the plurality of areas A step performed in the remaining areas except the area; And
Wherein the stretching is performed using a pair of gripping members holding the bonded web and the overlapping portion is divided into the plurality of areas in the stretching direction ,
Wherein the overlapping portion is divided into a gripping area, a welded area and a nonapplied area in a width direction of the bonded web, wherein in the width direction of the bonded web, the gap between the gripped area and the welded area is 0.05 times And the width of the welded area is 0.5 times or more and 0.9 times or less the width of the bonded web. The method according to claim 1,
And the welding is carried out at a portion apart from the grip portion gripped by the pair of gripping members. The method according to claim 1,
And the welding is carried out at a plurality of locations in the area. delete The method according to claim 1,
Wherein one of the pair of gripping means grips one end of the bonded web and the other of the pair of gripping means grips the other end of the bonded web, Lt; RTI ID = 0.0 > a < / RTI > width direction of the bonded web. 6. The method of claim 5,
Wherein the welding is carried out at a portion of the grip portion gripped by the gripping member at a distance from the gripping portion toward the center of the overlapping portion in the stretching direction. Forming a first polymer web;
Forming a second polymer web;
Running the first polymer web;
Running the second polymer web following the first polymer web;
Forming a series of bonded webs by fusing overlapping portions of the first polymer web and the second polymer web, wherein the overlapping portions include a longitudinally-extending rearward end of the first polymeric web and a longitudinally- The overlapping portion is divided into a plurality of areas, and the welding is performed in the remaining areas except for at least one of the plurality of areas; And
Wherein the stretching is carried out by using a pair of gripping members holding the bonded web, the overlapping portions are stretched in the plurality of areas in the stretching direction And a step for dividing,
Wherein the overlapping portion is divided into a gripping area, a welded area and a nonapplied area in the width direction of the bonded web, wherein in the width direction of the bonded web, an interval between the gripped area and the welded area is a width 0.05 times or more and 0.25 times or less, and the width of the welding area is 0.5 times or more and 0.9 times or less of the width of the width of the bonded web. 8. The method of claim 7,
Wherein one of the pair of gripping means grips one end of the bonded web and the other of the pair of gripping means grips the other end of the bonded web, Lt; RTI ID = 0.0 > width < / RTI > of the bonded web. 9. The method of claim 8,
Wherein the welding is carried out at a portion of the grip portion gripped by the gripping member at a distance from the gripping portion toward the center of the overlapping portion in the stretching direction. The method according to claim 1,
Wherein the step of forming the bonded web is characterized in that the bonding work per unit thickness is 0.4 W / m or more and 1.1 W / m or less. 8. The method of claim 7,
Wherein the step of forming the bonded web has a bonding work per unit thickness of 0.4 W / m or more and 1.1 W / m or less.

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