JP2007196635A - Plastic film roll and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic film roll which sees through the optimum method in a case that a plastic film is industrially manufactured using a static mixer and shows uniform tensile characteristics and thickness over the whole length of a long film. <P>SOLUTION: The plastic film roll is formed by taking up the plastic film with a length of 1,000-7,000 m. The plastic film is obtained by a method wherein two kinds of resins A and B different in chemical composition are respectively charged in separate extruders to be melted and the molten resins A and B are allowed to meet with each other to be passed through the static mixer, extruded from a T-die and closely brought into contact with a cooling roll to be cast to a film. The tensile strength at break, tensile elongation at break and thickness of all of samples cut out under a specific condition are received within a range of an average value of ±10% calculated therefrom. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plastic film roll in which a long plastic film having a laminated structure obtained by using two types of resin components having different chemical compositions as raw materials and using a static mixer in a production process and a method for producing the same. This plastic film roll is a roll around which a plastic film showing uniform tensile properties and thickness is wound substantially over the entire length of the film.

  2. Description of the Related Art Conventionally, a method for producing a film in which two or more different types of resins are melted separately and the melted resins are combined and passed through a static mixer has been proposed (for example, Patent Document 1). . These films were manufactured at a relatively small scale tester level.

By the way, in a production machine for industrially producing plastic film, production with a large discharge amount is required to improve productivity, and operating conditions performed at the test machine level cannot be immediately applied to the production machine. Absent. Usually, production machines are required to have stricter operating conditions than test machines. For example, the shear rate of the resin in the static mixer does not exceed 2 (1 / second) in the test machine (discharge amount less than 0.3 m ³ / hour), whereas the production machine (discharge amount 0.3 m ^3). / Hour or more) is 2 (1 / second) or more, and the technology that was completed in the testing machine is also incompatible with the production machine, resulting in the manifestation of various problems that were not recognized by the testing machine. .

  When a film is produced industrially by blending two kinds of resins, since a film having a substantially uniform composition is produced by transesterification, there has been almost no problem with scale-up. In industrial production of the film to be used, it is considered difficult to scale up because a multilayer (non-uniform) film is produced.

  For example, when the present inventors carried out a plastic film manufacturing method using a static mixer in a production machine, the obtained unstretched film and stretched film had poor appearance with streaky irregularities inside. The unevenness causes defects when surface post-processing such as printing and vapor deposition is performed. In addition, foreign matter is also generated in the film, and this foreign matter causes defects in appearance and defects when surface post-processing such as printing and vapor deposition is performed.

Further, if the scale-up is not successful, it is conceivable that the characteristics vary in the film length direction when a long film of 1000 m or more is manufactured. Normally, in any film application, a film is cut out to a desired size while being fed out from a roll. If the characteristics fluctuate in the length direction of the film as described above, There may be a problem that the characteristics vary.
JP 2003-266519 A

  Therefore, in the present invention, the optimum method for industrially manufacturing a plastic film using a static mixer is determined, and there is no defect in appearance over the entire length of the long film, and further, uniform tensile characteristics and thickness are exhibited. The issue of providing plastic film rolls was raised.

The present invention is a plastic film roll formed by winding a plastic film having a length of 1000 to 7000 m,
The plastic film is prepared by charging two types of resins A and B having different chemical compositions into separate extruders, melting them, joining the melted resins A and B, and passing them through a static mixer. It is obtained by sticking to a cooling roll after extrusion and forming a cast film,
The plastic film has a gist where it satisfies the following requirements (1) to (3).
(1) When the end portion on the winding start side of the film in the steady region where the film physical properties are stable in the length direction of the film is the first end portion, and the end portion on the winding end side is the second end portion, A first sample cutout is provided within 2 m inside the second end, and a final cutout is provided within 2 m inside the first end, and a sample is cut out every about 100 m from the first sample cutout. For each sample cutout part, a film sample with a length of 150 mm in the length direction of the film and a width of 10 mm, and a film sample with a length of 150 mm in the width direction of the film and a width of 10 mm are collected, When the tensile fracture strength in the length direction and the width direction of the film was measured for each sample based on JIS K 7127-1999 at a tensile speed of 100 mm / min, There is within a range within ± 10% of the mean values calculated from them,
(2) When the tensile fracture elongation in the length direction and the width direction of the film was measured in the same manner as described above, the tensile fracture elongation of all samples was within a range of ± 10% of the average value calculated therefrom. In the
(3) A film sample having a length in the length direction of 50 cm and a width of 5 cm was taken for each sample cutout portion in the requirement (1), and the thickness displacement measurement in the length direction was performed on this sample. At each sample cutout portion, the thickness variation defined by the following formula is within a range of 10% or less.
Thickness variation (%) = [(maximum thickness−minimum thickness) / average thickness] × 100
The present invention is a plastic film roll formed by winding a plastic film having a length of 1000 to 7000 m, and the plastic film is formed by combining two types of resin A layers and resin B layers having different chemical compositions. A plastic film roll having 100 layers or more and satisfying the above requirements (1) to (3) is also included.

  The present invention also includes a preferred method for producing the above-described plastic film roll of the present invention. This method comprises two types of resins A and B having different chemical compositions, which are fed into separate extruders A and B, respectively. The melted resin A and B are merged, passed through a static mixer, extruded from a T-die, and then brought into close contact with a cooling roll to form a cast film. The ratio ηA / ηB between the viscosity ηA and the melt viscosity ηB of the resin B immediately before joining is 0.5 to 2.0, and the shear rate γ (1 / second) of the resin in the static mixer is 2 to 100 (1 / second) ).

  The number of elements of the static mixer is preferably 3-18. In addition, if it is a film roll of Claim 2, it is preferable that the number of elements shall be 6-18. Further, each of the discharge amounts of the extruders A and B is controlled within the range of the average discharge amount ± 2%, and the rotation speed of the cooling roll is controlled within the range of the average rotation speed ± 2%. This is a preferred embodiment of the method of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the plastic film roll by which the long film by which the external appearance was favorable over the full film length, and the fluctuation | variation of the tensile characteristic and the fluctuation | variation of thickness was small was wound was able to be provided. Individual plastic film products obtained from this plastic film roll have small variations in quality, and defects in appearance are less likely to occur even when printing or vapor deposition is performed.

  Moreover, according to the method of the present invention, the plastic film roll can be produced industrially.

  The plastic film (manufacturing method will be described later) wound around the plastic film roll of the present invention needs to satisfy the requirements (1) to (3). Hereinafter, each requirement will be described.

  The following requirements (1) and (2) indicate that the tensile properties (tensile breaking strength and tensile breaking elongation) of the long film wound around the roll of the present invention have little variation over the entire length of the film. Yes.

(1) When the end portion on the winding start side of the film in the steady region where the film physical properties are stable in the length direction of the film is the first end portion, and the end portion on the winding end side is the second end portion, A first sample cutout is provided within 2 m inside the second end, and a final cutout is provided within 2 m inside the first end, and a sample is cut out every about 100 m from the first sample cutout. For each sample cutout part, a film sample with a length of 150 mm in the length direction of the film and a width of 10 mm, and a film sample with a length of 150 mm in the width direction of the film and a width of 10 mm are collected, When the tensile fracture strength in the length direction and the width direction of the film was measured for each sample based on JIS K 7127-1999 at a tensile speed of 100 mm / min, There is within a range within ± 10% of the mean values calculated from them,
(2) When the tensile fracture elongation in the length direction and the width direction of the film was measured in the same manner as described above, the tensile fracture elongation of all samples was within a range of ± 10% of the average value calculated therefrom. Is in the range.

  First, the meaning of the requirement (1) “steady region where film properties are stable in the length direction of the film” will be described. The “steady region where the film physical properties are stable in the length direction of the film” is a region where the film forming process and the stretching process are stably performed during film production, and the film physical properties are almost uniform. In the present invention, in the long film obtained when the film forming process and the stretching process are operated in a stable steady state, the technical idea is to make the tensile characteristics and thickness highly uniform than the conventional level. . In actual operation, during film production, the film characteristics may vary depending on the raw material supply method and film forming conditions, but in the present invention, the film obtained when the raw material supply amount and film forming conditions are unstable. It does not require uniformization. For this reason, it is assumed that the sampling for evaluating the characteristics requiring homogenization is performed only in the region where the film forming process and the stretching process are operated in a stable steady state, that is, the “steady region”.

  Therefore, for example, if the film is about 10 m from the beginning of winding of the roll when the steady operation is not performed, sampling is not performed from this portion, and the 10 m from the beginning of winding is sampled as the first end of the film.

  The number of the steady regions (steady operation regions) is usually one place per film roll (one place over the entire film roll). However, depending on the manufacturing situation, there may be a plurality of locations. In this case, sampling is performed only from the steady region. The steady region can be evaluated, for example, by measuring the thickness variation of the film by a method described later. In other words, a region where the thickness variation is within 20% may be regarded as a steady region.

  Subsequently, a sampling method will be described. For the film wound on one roll, when the end of the film in the steady region on the winding start side is the first end and the end on the winding end is the second end, the second end The first sample cutout portion is provided within 2 m from the first end portion, and the final cutout portion is provided within 2 m inside the first end portion, and the sample cutout portion is provided approximately every 100 m from the first sample cutout portion. By providing, samples are selected at approximately equal intervals over the entire length of the steady region of the film. Note that “about every 100 m” means that the sample may be cut out at about 100 m ± 1 m.

  The sampling method will be described in more detail. For example, when a film having a total length of a steady region and a length of 498 m is wound on a roll, the first sample (i) is cut out within 2 m from the end of winding of the film (second end). . Note that the area to be cut is appropriately set according to the physical property value to be measured.

  Subsequently, the second sample (ii) is cut out at a distance of about 100 m from where the first sample (i) was cut out. Similarly, the third sample (iii) is cut at about 200 m, the fourth sample (iv) is cut at about 300 m, and the fifth sample (v) is cut at about 400 m. Here, since the remainder becomes shorter than 100 m, the sixth (final) sample (vi) cuts out any portion within 2 m from the start of winding (first end) of the film.

  The requirement (1) of the present invention is that when the tensile fracture strength in the length direction and the width direction of the film is measured for all the samples cut in this way, the tensile fracture strengths of all the samples are determined from these, respectively. It is within the range of ± 10% of the calculated average value. That is, for example, if the average value of the tensile fracture strength in the length direction of the film is 50 MPa, it is sufficient that the tensile fracture strengths of all the samples for length direction measurement are within the range of 45 to 55 MPa. Of the tensile fracture strength of each sample, both 100 × (maximum value−average value) / average value and 100 × (average value−minimum value) / average value should be smaller than 10%. If the fluctuation width exceeds 10%, after film production, when the film is slit in the length direction and divided into a plurality of rolls, the tension applied to the film is not constant, and the roll form is poor. It is not preferable. Further, when cutting into smaller sizes to obtain individual plastic film products, the mechanical strength varies from product to product, resulting in a high defect rate. The fluctuation range of the tensile fracture strength is more preferably within ± 8% of the average value in the length direction and the width direction of the film, and more preferably within ± 6% of the average value. In actual operation, the tensile fracture strength of all the samples cannot be the same measured value, that is, the average value cannot be ± 0%, so the lower limit of the fluctuation range is ± 1%.

  The tensile properties in the length direction of the film (tensile breaking strength and tensile elongation at break) were measured using a sample having a length in the length direction of 150 mm, and the tensile properties in the width direction of the film were measured in the width direction of the film. Measurement is performed using a sample having a length of 150 mm.

  The requirement (2) is that, when the tensile fracture elongation in the length direction and the width direction of the film is measured for all the samples, the tensile fracture elongation of all the samples is ±± of the average value calculated from them. It is within the range of 10%. If the variation in tensile elongation at break exceeds ± 10%, the same inconvenience as in the case of tensile strength can occur. The fluctuation range of the tensile breaking elongation is more preferably within ± 8% of the average value in the length direction and the width direction of the film, and further preferably within ± 6% of the average value. In addition, the lower limit of the fluctuation range in tensile fracture elongation is ± 1%.

  In the tensile test, a specimen of JIS K 7127 type 2 was used, and the sample was placed at a temperature of 23 ° C. in a tensile tester (for example, “STM-T” manufactured by Baldwin) so that the distance between chucks was 100 mm. The sample is set and pulled in the length direction of the sample at a pulling speed of 100 mm / min. The strength at the time of failure is defined as tensile fracture strength (MPa), and the elongation is defined as tensile fracture elongation (%). The absolute values of these measured values are not particularly limited because they vary depending on the types of resins A and B used.

The plastic film roll of the present invention needs to satisfy the following requirement (3).
(3) A film sample having a length in the length direction of 50 cm and a width of 5 cm was taken for each sample cutout portion in the requirement (1), and the thickness displacement measurement in the length direction was performed on this sample. At each sample cutout portion, the thickness variation defined by the following formula is within a range of 10% or less.
Variation in thickness = [(maximum thickness−minimum thickness) / average thickness] × 100
From each sample obtained from each sample cut-out part, create a plurality of test pieces with a length of 50 cm and a width of 5 cm in the length direction of the film, and measure the thickness of the test piece in the length direction with a contact thickness meter, The maximum thickness, the minimum thickness, and the average thickness are obtained, and the thickness variation in the test piece is calculated according to the above formula. That is, one thickness variation is calculated in one sample cutout part. The requirement (3) requires that the thickness variation in the length direction of the film is 10% or less in all the sample cutout portions. May be 10% or less.

  If there is a portion where the thickness variation in the length direction exceeds 10%, when the long film is cut into individual plastic film products, the thickness varies from product to product, resulting in a high defect rate. Therefore, it is not preferable. In addition, when the thickness variation is small, color misregistration can be prevented and printability can be improved when performing multicolor printing in which a plurality of colors are superimposed on a film. In addition, when the uniformity of the film thickness is increased, it is easy to superimpose the bonded portions when processing the film into a tube or the like by solvent bonding. In addition, when multicolor printing is performed on the film, wrinkles can be prevented from easily entering the film, and the film can be prevented from meandering during traveling, thereby improving workability (stable workability). Furthermore, it is possible to prevent a difference in partial winding hardness from occurring in a state where the film is wound in a roll shape, and to prevent the film from being loosened or wrinkled and greatly deteriorating the appearance of the film. The preferred thickness variation in the film length direction is 9% or less, more preferably 8% or less.

  In addition, when a test piece having a length in the width direction of the film of 50 cm and a width of 5 cm is used in the same manner as described above, the thickness variation in the film width direction is obtained, but the thickness variation in the film width direction is also 10% or less. It is preferable.

  Next, the manufacturing method of the plastic film roll of this invention is demonstrated. In the plastic film roll of the present invention, two types of resins A and B having different chemical compositions are put into separate extruders and melted, and the melted resins A and B are merged and passed through a static mixer. -It is obtained by extruding from a die and then bringing it into close contact with a cooling roll to form a cast film. The resulting film has 100 layers or more in total of two types of resin A layers and resin B layers having different chemical compositions.

The present invention presupposes the production of plastic film rolls at the production machine level. Production of a plastic film at the production machine level means production in the case where the amount of resin discharged from the extruder per hour is 0.3 m ³ / hour or more. Considering production efficiency, the discharge rate is preferably 0.5 m ³ / hour or more, and more preferably 1 m ³ / hour or more.

  In the present invention, two types of resins A and B having different chemical compositions are used. This is because by using the resins A and B, they are agitated inside the static mixer, and a film having a multilayered laminated structure having the advantages of the resins A and B is obtained. Resins A and B may each be composed of a single type of resin, or may be a blend resin in which two or more types of resins are mixed. In addition, “different in chemical composition” of “two types of resins A and B having different chemical compositions” means that the composition of monomers constituting each resin is different. For example, i) resin A is a resin In the case where it is configured to include a monomer unit different from that of B, ii) the resin A and the resin B are composed of a copolymer composed of the same type of monomer unit, but the ratio between the copolymerized monomer units ( When the copolymerization composition ratio) is different, iii) the resin A and the resin B are both blended resins in which the same kind of resin is mixed, but the resin A and the resin B have different resin blend ratios.

  The types of the resin A and the resin B are not particularly limited as long as they can be melt-extruded and can be formed into a film by a cooling roll. The resin A and the resin B are preferably resins that are not compatible with each other. When resins that are incompatible with each other are used as raw materials, a multilayer structure in which the resin A and the resin B are alternately laminated can be formed in the obtained film without much disturbance.

  As an example of a resin that can be used, first, a polyester having a wide application range can be given. Examples of the polyester include crystalline polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polypentamethylene terephthalate, polyhexamethylene terephthalate, and polyethylene-2,6-naphthalate (PEN). Or a polyester having a relatively high crystallinity (highly crystalline polyester) obtained by copolymerizing an acid component and / or a glycol component, which will be described later, in an amount of 10 mol% or less in 100 mol% of the acid component and / or glycol component. Can be used. Furthermore, based on polyethylene terephthalate (PET), dimer acid is copolymerized to 10 mol% or less (PET-D), or polyethylene-2,6-naphthalate (PEN) is copolymerized to 10 mol% or less of isophthalic acid. It is also possible to use. More preferred are PBT, PTT and PET-D.

  When the highly crystalline polyester is the resin A, a polyester having relatively low crystallinity may be used as the resin B. For example, based on a polyester composed of terephthalic acid as the acid component and ethylene glycol as the glycol component, the dicarboxylic acid having a difference of 5 mol% or more, preferably 6 mol% or more and less than 40 mol%, in 100 mol% of the acid component and / or glycol component Examples thereof include polyesters obtained by copolymerizing components and / or glycol components. Specific monomer components include, for example, dicarboxylic acid components such as aromatic dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid, and orthophthalic acid, and aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, and decanedicarboxylic acid. And alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid. Examples of the glycol component include aliphatic diols such as propanediol, butanediol, neopentylglycol, and hexanediol; alicyclic diols such as 1,4-cyclohexanedimethanol, and aromatic diols. Among them, preferred is a copolymer of 7 mol% or more and 35 mol% or less neopentyl glycol and / or 1,4-cyclohexanedimethanol based on a polyester composed of terephthalic acid as an acid component and ethylene glycol as a glycol component. Polyester.

  Polystyrene resins are also mentioned as preferable resins. The polystyrene-based resin is styrene as a monomer component; p-, m- or o-methylstyrene, 2,4-, 2,5-, 3,4- or 3,5-dimethylstyrene, pt-butyl. Alkylstyrenes such as styrene; halogens such as p-, m- or o-chlorostyrene, p-, m- or o-bromostyrene, p-, m- or o-fluorostyrene, o-methyl-p-fluorostyrene Halogenated alkyl styrene such as p-, m- or o-chloromethyl styrene; alkoxy styrene such as p-, m- or o-methoxy styrene, p-, m- or o-ethoxy styrene; Carboxyalkylstyrenes such as m- or o-carboxymethylstyrene; alkyl ethers such as p-vinylbenzylpropyl ether Emissions; p-trimethylsilyl styrene alkylsilyl styrene; vinyl benzyl dimethoxyphosphinyl sulfide or the like using one or more, a polymer obtained by a known radical polymerization or the like. A copolymer of acrylonitrile and a styrene monomer, an ABS resin, or the like can also be used. These polystyrene resins can be used in any of a syndiotactic structure, an atactic structure, and an isotactic structure.

  Polyolefin resins can also be preferably used. The polyolefin-based resin is one kind of α-olefin having about 3 to 20 carbon atoms such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methylpentene, 1-decene or the like. A polymer containing two or more monomer components. Moreover, you may use the cyclic olefin which has an ethylenically unsaturated bond and an alicyclic structure as 1 type of a monomer component. Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of mechanical strength, heat resistance, and the like. The number of carbon atoms constituting the alicyclic structure is preferably 4 to 30, and the proportion of the repeating unit having the alicyclic structure is preferably 50% by mass or more. Specific examples of the alicyclic structure-containing polymer include, for example, (1) a norbornene polymer, (2) a monocyclic olefin polymer, (3) a cyclic conjugated diene polymer, and (4) a vinyl alicyclic ring. And a hydrocarbon-based polymer, and hydrogenated products thereof.

  Polyacrylic resins can also be used. Polyacrylic resins include acrylic acid, methacrylic acid, lower alkyl esters thereof (for example, esters such as methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, 2-ethylhexyl), hydroxymethyl (meth) acrylate In this case, the main component is a (meth) acryloyl group-containing monomer such as glycidyl (meth) acrylate, and radical polymerization is carried out with another vinyl monomer (such as the styrene monomer) as necessary.

  Further, nylons such as nylon 6, nylon 66, nylon 9, nylon 6-10, nylon 11, nylon 12, nylon 6T, nylon 6T / 6I and nylon 6I can also be used.

  In order to produce a plastic film, first, two types of resins A and B having different chemical compositions are put into separate extruders and melted. Prior to feeding into the extruder, the resin may be dried under heating and / or vacuum as necessary. In an extruder for melting, it is necessary to appropriately adjust the melting temperature of the resin according to the melting point, glass transition temperature, softening temperature, etc. of the resin, but the resin can be discharged from the extruder in a molten state. Therefore, it is necessary to determine the thermal degradation. As a guide, when the resin used is polyester, nylon, polystyrene resin, or polyacrylic resin, the viscosity as a molten resin at a shear rate of 20 (1 / second) is about 200 to 700 Pa · s, and the resin is polyolefin. In the case of a resin, the temperature may be set to about 300 to 1200 Pa · s. In the case of a crystalline resin, a temperature about 10 to 40 ° C. higher than the melting point of the resin may be used as a guide. For each resin, conventionally known additives such as organic particles (eg, crosslinked acrylic particles, crosslinked styrene particles, silicone particles), inorganic particles (eg, silica, kaolin, clay, calcium carbonate) are used as necessary. , Aluminum oxide, barium sulfate, zinc oxide, zinc sulfide, etc.), lubricants, stabilizers, colorants, antioxidants, antifoaming agents, antistatic agents, ultraviolet absorbers, and the like.

  Resins A and B melted by the extruder are joined together in the molten state. “Merging” means that resin A and resin B come into contact with each other in the same flow path. The merging may be performed before charging into the static mixer or may be performed at the moment when charging into the static mixer. Further, a feed block may be disposed immediately before the static mixer.

  In FIG. 1, the schematic diagram of the typical implementation apparatus which can manufacture the plastic film roll of this invention was shown. Gear pumps A and B are connected to the outlets of the extruder A for the resin A and the extruder B for the resin B, respectively, and the feed block is connected by piping. The feed block is connected to the inlet of the static mixer. In this apparatus, the joining of the resin A and the resin B is performed in the feed block. In addition, when not using a feed block, it is good to make it merge by static mixer inlet side piping.

  In the present invention, it is necessary that the ratio ηA / ηB of the melt viscosity ηA of the resin A and the melt viscosity ηB of the resin B immediately before the merge (when reaching the feed block inlet) is 0.5 to 2.0. When a plastic film manufacturing method using a static mixer is industrially carried out by a production machine, streaky unevenness generated in the resulting film has a large difference in melt viscosity between separately melted resins. It is presumed that the disturbance occurs at the contact interface at the moment when the resins of the seeds join (contact). However, by setting the ratio ηA / ηB within the above range, the generation of the disturbance of the interface is reduced. As a result, it is possible to suppress the occurrence of streaky unevenness in the obtained film. The lower limit of ηA / ηB is more preferably 0.53, and the upper limit is 1.9. In addition, when blending 2 or more types of polymers as the resin A or B, a value obtained by measuring the melt viscosity of each polymer and arithmetically averaging it may be used as the melt viscosity of the resin.

  The amount of the resin A and the resin B at the time of merging, that is, the ratio of the discharge amount of the extruder A and the extruder B may be appropriately selected according to the intended characteristics of the obtained film, but A / B = It is preferable to set it as 95 / 5-5 / 95, and 85 / 15-15 / 85 is a more preferable range.

The joined resins are laminated or mixed by a static mixer in a molten state. The static mixer is an element in which a rectangular plate is twisted 180 degrees alternately in a resin flow path, and the number of layers doubles each time one element passes through this element. Therefore, logically, when passing through n elements, it becomes a ²ⁿ layer or a ^{2n + 1} layer, but in reality, it may change depending on the relationship between the flow path diameter, the discharge amount, the viscosity and surface tension of each resin, etc. .

  The size of the element of the static mixer is preferably 1 to 3, and more preferably 1.5 in terms of L / D ratio (ratio represented by the length of one element / mixer inner diameter). Although the plate | board thickness of the part twisted is not specifically limited, About 2-6 mm is preferable. The number of elements inside the static mixer is preferably 3-18, and more preferably 6-14. If the amount is too small, the function as a multilayer film cannot be exhibited. If the amount is too large, the performance is not different from that of a film produced by simply blending. In order to exhibit the suitable characteristics of Resin A and Resin B, the total number of layers of 100 or more is preferable, and for that purpose, the number of elements is preferably 6 or more.

In the present invention, it is important to set the shear rate γ (1 / second) of the merged molten resins A and B in the static mixer to 2 to 100 (1 / second). When a plastic film manufacturing method using a static mixer is industrially carried out by a production machine, it is assumed that the foreign matter generated in the resulting film is generated by the molten resin staying in the process for a long time and deteriorating. Is done. Therefore, the generation of this foreign matter can be suppressed by setting the shear rate in the static mixer to 2 or more. Further, if the shear rate exceeds 100 (1 / second), it becomes difficult to control the pressure in the extrusion process, or it is necessary to make the pressure resistant specification, which increases the cost of production equipment and is not economically preferable. . The lower limit of γ (1 / second) is preferably 3, more preferably 5, more preferably 8, and the upper limit of γ (1 / second) is preferably 90, more preferably 70, still more preferably 50. is there. The shear rate is defined as a velocity gradient when a viscous fluid passes between parallel plates. The pipe having a circular cross section, that is, the shear rate inside the static mixer is determined by the cross sectional area of the pipe of the mixer in which the element is arranged (radius is r (mm)) and the amount of resin Q (mm ³ / mm) flowing in the mixer. Second). The amount of resin flowing in the mixer may be the sum of the discharge amounts of the extruder A and the extruder B. Since the shear rate γ (1 / second) in the mixer is 4Q / πr ³ , the discharge amounts of the extruders A and B and the inner diameter of the static mixer may be set so that this value falls within the above range. In order to keep the discharge rate of extruders A and B constant, it is preferable to use a highly quantitative gear pump, and a pump with a helical type gear or a pump with two parallel gears is recommended. Is done. The discharge amount is preferably within the range of the average discharge amount ± 2%. By using these pumps, a long film satisfying the requirements (1) to (3) can be obtained.

  The resin A and the resin B are usually at different temperatures in order to obtain an appropriate melt viscosity. In order to prevent thermal deterioration inside the static mixer, it is preferable to set the temperature below the temperature of the high temperature resin. The lower limit of the temperature is not particularly limited as long as there is no problem in the fluidity of the resin, but it is usually preferable to set the temperature lower than the temperature of the resin having a low temperature. When the number of elements of the static mixer is large (when the mixer is long), it is preferable to provide multiple temperature control units because precise control is possible. The total length of the static mixer may be the same, or the temperature may be reduced toward the downstream side. It may be controlled so as to go down. Lowering the temperature is effective in suppressing thermal degradation of the resin. The lowering temperature is preferably 10 ° C. or lower. In addition, the fluidity of the resin on the high temperature side is not substantially a problem as long as the residence time in the static mixer is about 10 minutes or less.

  The molten resin laminated or mixed by the static mixer is guided to a T-die, extruded from the T-die onto a cooling roll, and formed into a cast film. When extruding the molten resin onto the cooling roll, it is preferable that the molten resin is brought into close contact with the cooling roll by electrostatic force using electrodes such as a wire shape, a tape shape, a needle shape, or a knife shape and rapidly solidified. The surface temperature of the cooling roll may be selected according to the types of the resin A and the resin B to be used, which is usually adopted in the production of the resin film. Further, an air knife method may be adopted.

  In the resin path from the extruder to the T-die, it is necessary to prevent pressure loss. If a significant pressure loss occurs in the path, it is not preferable because a turbulent flow of resin occurs in that portion, and a deteriorated product is likely to be generated, or the laminated structure of the film is disturbed. In addition, temperature control in the extruder, gear pump, static mixer, T-die, and piping between these devices is PID control (proportional operation P, integral operation I) that can be controlled more precisely than normal on / off control. The differential operation D) is preferably performed. In addition, you may interpose a filter suitably between these apparatuses.

  A variation factor of the thickness in the length direction of the film in the film roll includes a variation in the rotation speed of the cooling roll in the casting process for cooling the film after melt extrusion. Regarding the fluctuation of the rotation speed of the casting roll, it is preferable to control the rotation accuracy of the roll drive system by an inverter or the like so that the fluctuation of the rotation speed of the casting roll is within the range of the average speed ± 2%. The average speed of the casting roll is preferably 50 to 100 m / min in the case of a film stretched after casting, and 60 to 150 m / min in the case where stretching is not performed after casting.

  The obtained cast film may be stretched uniaxially or biaxially as necessary. The stretching direction (longitudinal direction, lateral direction) for uniaxial stretching and the method (simultaneous stretching, sequential stretching) for biaxial stretching may be appropriately determined according to the characteristics required for the obtained film. Further, the stretched film may be subjected to heat treatment in order to impart flatness and dimensional stability.

  When stretching, it is recommended to reduce the fluctuation of the surface temperature of the film as much as possible by suppressing the temperature fluctuation in the process of preheating and stretching the film to obtain a long film with uniform characteristics. The

When uniaxially stretching in the transverse direction using a tenter, there are a preheating step before stretching, a stretching step, a heat treatment step after stretching, a relaxation treatment, a restretching treatment step, etc., but in particular, a preheating step, stretching In the process and the heat treatment process after stretching, it is recommended that the fluctuation range of the surface temperature of the film measured at each arbitrary point is within an average temperature ± 1 ° C, preferably within an average temperature ± 0.5 ° C. . This is because if the fluctuation range of the surface temperature of the film is small, the film is stretched or heat-treated at the same temperature over the entire length of the film, and the thickness and physical properties of the film become uniform. In particular, temperature fluctuations in the preheating process and the stretching process greatly affect the film thickness fluctuation, and temperature fluctuations in the stretching process and the heat treatment process after stretching affect the tensile properties of the film. It is preferable to use a controllable heating facility or stretching facility. As equipment for controlling film temperature, for example, an inverter is installed to control the wind speed of the tenter's hot air to suppress fluctuations in the wind speed, and low pressure steam with a pressure of 500 kPa (5 kgf / cm ² ) or less is used as the heat source. Thus, it is preferable to suppress temperature fluctuations of the hot air. Of course, it is preferable that the fluctuation range of the surface temperature of the film is small also in the relaxation treatment and the re-stretching treatment step.

  The fluctuation range of the surface temperature of the film measured at an arbitrary point is, for example, when the film surface is continuously produced by, for example, an infrared non-contact surface thermometer, etc., after 2 m has elapsed from the start of the stretching process. The fluctuation range when measuring. Since the average temperature can be calculated when film production for one roll is completed, if the fluctuation range of the surface temperature of the film is within ± 1 ° C. of the average temperature, the film is stretched under the same conditions over the entire length of the film. In other words, variations in film thickness and tensile properties are also reduced.

  When the production method described above is adopted and a film is produced under the same conditions, a film having a multilayer structure having an excellent appearance and uniform tensile properties and thickness over the entire length of the long film can be obtained on an industrial scale. The number of layers may be confirmed with an electron microscope or the like, and the method employed in the present invention will be described in Examples. The number of layers is preferably 100 or more in total of the A layer and the B layer, more preferably 500 to 100,000, and most preferably 1000 to 10,000.

  The plastic film roll in the present invention is obtained by winding a plastic film on a winding core (core) with a length of 1000 m to 7000 m. The film width is preferably 0.2 m or more. A roll of a film having a width of less than 0.2 m has a low industrial utility value, and a film roll having a width of less than 1000 m covers the entire length of the film because the roll length of the film is small. Since fluctuations in thickness and tensile properties are reduced, the effects of the present invention are hardly exhibited. The width of the film roll is more preferably 0.3 m or more, and further preferably 0.4 m or more. The upper limit of the width of the film roll is not particularly limited, but a width of 1.5 m or less is generally preferable because of easy handling. As the winding core, paper tubes, plastic cores, and metal cores such as 3 inches, 6 inches, and 8 inches can be usually used. Moreover, the thickness of the film which comprises the plastic film roll of this invention does not specifically limit, According to a use, it can select suitably.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not restrict | limited to these Examples at all. First, the evaluation method of the film created in the Example and the comparative example is demonstrated.

(1) Melt Viscosity The melt viscosity at the resin temperature immediately before joining the static mixer was measured using a capillograph (manufactured by Toyo Seiki Co., Ltd .; model CAPILOGRAPH 1B). The shear rate γ at the time of viscosity measurement was 20 (1 / second), and measurement was performed using a capillary having an inner diameter of 1 mmφ and a length of 10 mm.

(2) Shear rate As described above, from the radius r (mm) of the static mixer and the amount of resin Q (mm ³ / sec) flowing through the mixer (the total discharge amount of the extruder A and the extruder B), The shear rate γ = 4Q / πr ³ was calculated.

(3) Roll winding shape When a 0.6 m wide film is wound on a winding core of 2000 m and a diameter of 3 inches, if there are no wrinkles or streaks on the outer periphery or end face of the roll, ○ X.

(4) Confirmation of steady region In order to determine whether or not the region is a steady region, five sample cutout portions are provided every 20 m from 0 m from the end of winding of the film, and further inside (winding end) from 100 m from the start of winding. Direction) is provided with five sample cutouts every 20 m. A sample having a length of 50 cm and a width of 5 cm in the length direction of the film is cut out from each sample cut-out portion, and 10 pieces of the test pieces are prepared in each direction for each sample cut-out portion. Using the meter [“KG60 / A”; manufactured by Anritsu Co., Ltd.], the thickness in the length direction of each test piece was continuously measured and output to the chart. From this output result, the maximum thickness, the minimum thickness, and After obtaining the average thickness and calculating the thickness fluctuation based on the following formula, the average value was taken as the thickness fluctuation in each direction of the film in each sample cutout portion.
Thickness variation (%) = [(maximum thickness−minimum thickness) / average thickness] × 100
In all the film rolls described later in Examples and Comparative Examples, the thickness variation of all the test pieces was within 20%. Furthermore, the conditions of the film forming process and the stretching process were stable over the entire region from the start to the end of winding of the film. Accordingly, the entire region corresponds to the steady region in any of the films wound on the film rolls described later in this example and the comparative example.

(5) Sample cutout part As described above, the film wound on the film roll described later in this example / comparative example was the first because all the regions corresponded to the steady region. The sample cut-out part was the film winding end part (0 m from the winding end), and the final cut-out part was the film winding start part (0 m from the winding start), and a sample cut-out part was provided every 100 m. Therefore, there were 19 sample cutouts in the 2000 m film in total.

(6) Film appearance From each sample cutout part in (5), the film is cut into 1 m ² squares, placed on a black mount, and the film on the mount is white fluorescent lamp (“FLR40S” manufactured by Toshiba Corporation; three-wavelength type; Place the two in parallel. Considering the case where the fluorescent lamp and the film are parallel to each other as 0 degree, the film is tilted by 20 to 80 degrees, the fluorescent lamp is reflected on the film, and unevenness inside the film is visually observed. X when multiple linear irregularities are visible inside any film sample, Δ when slight (about one) linear irregularities are visible in any film sample, all film samples When no unevenness was seen in the circle, it was rated as ○.

(7) Foreign matter When a 1 m ² film is cut out from each sample cutout part in (5) and one or more foreign matters having a long side of 0.5 mm or more are recognized in any of the film samples, ×, all film samples If it was not, it was rated as ○

(8) Number of layers inside the film The number of layers inside the film was determined by observing the film cut out from the final sample cutout section using a transmission electron microscope. First, the film was embedded in an epoxy resin. As the epoxy resin used, a mixture of Luabeck 812, Luavec NMA (manufactured by Nacalai Tesque) and DMP30 (manufactured by TAAB) in a ratio of 100: 89: 3 was used. Next, after embedding the sample film in the above-described mixed resin, the sample film was left in an oven adjusted to a temperature of 60 ° C. for 16 hours to cure the resin and obtain an embedded block.

  The obtained embedding block was attached to an ultra cut N manufactured by Nissan Sangyo Co., Ltd., and an ultrathin section was prepared. First, trimming was performed using a glass knife until a cross section of a portion desired to be observed for the film appeared on the resin surface. Next, an ultrathin section was cut out using a diamond knife (manufactured by Sumitomo Electric; Sumiknife SK2045). The cut sections were collected on a mesh and then stained by standing in a ruthenium tetroxide vapor for 30 minutes at room temperature, followed by thin carbon deposition.

  The electron microscope observation was performed using JEM-2010 manufactured by JEOL under the condition of an acceleration voltage of 200 kV. The obtained image was recorded on an imaging plate (Fuji Photo Film; FDL UR-V). A signal recorded on an imaging plate is read out using digital luminography (manufactured by JEOL; Pixsys TEM), recorded as digital image information on a Windows personal computer, and a layer that is confirmed from the difference in staining degree between layers A and B I counted the number of.

(9) Thickness variation A sample having a length of 50 cm and a width of 5 cm in the length direction of the film and a sample having a length of 20 cm and a width of 5 cm in the width direction of the film were cut out from each sample cutout portion (sample for measuring thickness displacement). ). Ten test pieces were prepared in each direction for each sample cutout portion. After that, as in the case of the confirmation of the steady region, the thickness in the length direction of each test piece is continuously measured using the contact-type thickness meter and output to the chart. Then, after obtaining the minimum thickness and the average thickness and calculating the thickness variation based on the following formula, the average value was defined as the thickness variation in each direction of the film in each sample cutout portion.
Variation in thickness = [(maximum thickness−minimum thickness) / average thickness] × 100

(10) Tensile properties From each sample cut-out part, a film sample with a length of 150 mm and a width of 10 mm and a film sample with a width of 150 mm and a width of 10 mm are each 10 pieces. Samples were taken one by one, and the sample was set at a temperature of 23 ° C. in a tensile tester (“STM-T” manufactured by Baldwin) so that the distance between chucks was 100 mm, and the sample length direction was 100 mm / min. Pulled on. The strength at the time of failure was defined as tensile fracture strength (MPa), the elongation was defined as tensile fracture elongation (%), and the average value of 10 sheets was defined as the tensile fracture strength and tensile fracture elongation at each sample cut-out portion. Furthermore, the average value of the entire film was calculated from the tensile fracture strength and tensile fracture elongation of each sample cut-out portion, and the fluctuation range on the maximum value side and the fluctuation range on the minimum value side were calculated.

Synthesis Example 1 (Synthesis of polyester)
In an esterification reactor, 57036 parts by mass of terephthalic acid (TPA), 33244 parts by mass of ethylene glycol (EG), 15733 parts by mass of neopentyl glycol (NPG), 23.2 parts by mass of antimony trioxide (polymerization catalyst) , 5.0 parts by weight of sodium acetate (alkali metal compound) and 46.1 parts by weight of trimethyl phosphate (phosphorus compound) were charged, the pressure was adjusted to 0.25 MPa, and the mixture was stirred at a temperature of 220 to 240 ° C. for 120 minutes. The reaction was carried out. The reaction vessel was restored to normal pressure, 3.0 parts by mass of cobalt acetate tetrahydrate and 124.1 parts by mass of magnesium acetate tetrahydrate (alkaline earth metal compound) were added, and the temperature was 240 ° C. for 10 minutes. After stirring, the pressure was reduced to 0.5 hPa over 75 minutes and the temperature was raised to 280 ° C. Stirring was continued until the melt viscosity reached 4500 poise at a temperature of 280 ° C. (about 70 minutes), and then discharged into water in the form of a strand. The discharged material was cut with a strand cutter to obtain a polyester chip a. The intrinsic viscosity of the polyester chip a was 0.75 dl / g.

  The intrinsic viscosity was measured at 30 ± 0.1 ° C. with an Ostwald viscometer after precisely weighing 0.1 g of a chip and dissolving in 25 ml of a mixed solvent of phenol / tetrachloroethane = 3/2 (mass ratio). . The intrinsic viscosity [η] is obtained by the following formula (Huggins formula).

Here, η _sp : specific viscosity, t ₀ : solvent dropping time using Ostwald viscometer, t: film solution dropping time using Ostwald viscometer, and C: film solution concentration. In the actual measurement, the intrinsic viscosity was calculated by the following approximate equation where k = 0.375 in the Huggins equation.

Here, η _{r is the} relative viscosity.

Synthesis example 2
Polyester raw material chips b to having the chip composition shown in Table 1 were obtained in the same manner as in Synthesis Example 1. In the table, NPG is neopentyl glycol, DEG is diethylene glycol, PD is 1,3-propanediol, CHDM is 1,4-cyclohexanedimethanol, and BD is 1,4-butanediol.

Example 1
The film roll was manufactured with the manufacturing apparatus shown in FIG. Each chip obtained in the above synthesis example is separately preliminarily dried, and chip a and chip b are placed at a ratio of 8: 2 (mass ratio) in a hopper (not shown) immediately above the extruder A and a fixed screw feeder (not shown). The mixture was mixed in the hopper and continuously melted and extruded with a single screw extruder A at 275 ° C. ± 2 ° C. (resin A). In this extruder A, the shaft was 200 mmφ, L / D = 25, and the discharge amount was 0.972 m ³ / hour (= 1268 kg / hour).

Separately, chip a and chip b are fed into the hopper (not shown) directly above the extruder B at a ratio of 2: 8 (mass ratio), separately and continuously with a fixed screw feeder (not shown). And melt extrusion with a single screw extruder B (resin B) at 255 ° C. ± 2 ° C. In this extruder B, the shaft was 100 mmφ, L / D = 25, and the discharge amount was 0.243 m ³ / hour (= 317 kg / hour). In the extruders A and B, a gear pump in which helical gears having diagonal grooves were arranged in two stages in parallel was used, and the discharge amount was suppressed to a range within an average discharge amount ± 2%.

  The resin melted by both extruders is led to a feed block at 265 ° C. ± 2 ° C. so that resin A / resin B = 8/2 (discharge amount ratio), and further, a static mixer (Noritake, 265 ° C. ± 2 ° C.) 12 elements) manufactured by the company were passed through a T-die at 265 ° C. ± 2 ° C. and melt extruded into a film. The static mixer element is a 180 mm twisted metal plate with a thickness of 4 mm, and has a length (equivalent to the inner diameter of the mixer) of 68.2 mm and a length of 102.3 mm (L / D = 1.5). Using. When connecting the elements, the nth end face and the (n + 1) th end face were connected so as to be orthogonal to each other at 90 degrees. The odd-numbered elements were twisted clockwise and the even-numbered elements were twisted counterclockwise. Temperature control in all apparatuses was performed by PID control.

The total extrusion amount of the resins A and B is 1.215 m ³ / hour (corresponding to 1580 kg / hour), and the inner diameter of the mixer is 68.2 mm (2r). Therefore, the shear rate γ in the mixer is 10.8. (1 / second).

  The extruded resin was electrostatically adhered onto a cooling (casting) roll having a surface temperature of 25 ° C. ± 2 ° C. to obtain an unstretched cast film. The rotation speed of the casting roll was controlled by an inverter, and fluctuations in the rotation speed of the casting roll were suppressed within a range of ± 2% within the average speed (62 m / min).

  The unstretched cast film was preheated at 75 ° C. with a metal roll as it was, and then stretched 1.1 times at 80 ° C. with a silicone rubber roll. The longitudinally stretched sheet was preheated in a tenter at 82 ° C. for 24 seconds, subsequently stretched 4.8 times in the transverse direction at 77 ° C., and then heat treated at 70 ° C. for 24 seconds to obtain a thickness of 45 μm and a length of A heat-shrinkable polyester film having a length of 2000 m or more was obtained. The obtained film was slit into a width of 0.6 m and a length of 2000 m and wound up on a 3-inch paper tube to obtain a film roll. The production conditions are shown in Table 2, and the evaluation results of the obtained film rolls are shown in Tables 4-6. The number of laminated films in Example 1 was 2420.

  Moreover, in Example 1, the fluctuation range of the temperature of the film surface when the film was continuously produced was the average temperature ± 1.5 ° C. in the tenter preheating step, the average temperature ± 2.5 ° C. in the stretching step, and the heat treatment step The average temperature was in the range of ± 2.0 ° C.

Comparative Example 1
An unstretched cast film was obtained in the same manner as in Example 1, except that the total discharge amount of the resin in Example 1 was 0.213 m ³ / hour (277 kg / hour). The cast film was not stretched because the appearance was poor and many foreign substances were generated. The production conditions are summarized in Table 2.

Comparative Example 2
An unstretched cast film was obtained in the same manner as in Example 1 except that the inner diameter of the static mixer was 120.0 mm. The cast film was not stretched because the appearance was poor and many foreign substances were generated. The production conditions are summarized in Table 2.

Comparative Example 3
A film roll was obtained in the same manner as in Example 1 except that the temperature of the resin A was 225 ° C. The production conditions are shown in Table 2, and the evaluation results of the obtained film rolls are shown in Tables 4-6. The number of laminated films in Comparative Example 3 was 2380.

Reference example (film formation experiment with an experimental machine)
A single screw extruder (60 mmφ, L / D = 25) having a small scale was used instead of the extruder A in Example 1, and a twin screw extruder (22.5 mmφ × 2, L / D) was used instead of the extruder B. Resins A and B were extruded and passed through a static mixer in the same manner as in Example 1 except that D = 25) was used. The total discharge amount was 0.03 m ³ / hour. In the static mixer, the number of elements was the same as that in Example 1 (12), but the length was 38.4 mm and L / D = 1.5. After passing through the static mixer, an unstretched cast film was obtained in the same manner as in Example 1, preheated, stretched and heat-set, and a film roll wound with a heat-shrinkable polyester film having a thickness of 45 μm and a length of 800 m was obtained. Obtained. In the experimental machine, since the discharge amount was smaller than that in the production machine, the shear rate in the mixer was low, but the appearance of the film was good and no foreign matter was observed. The production conditions are shown in Table 2, and the evaluation results of the obtained film rolls are shown in Tables 4-6. The number of laminated films in Reference Example 1 was 2340.

Example 2
Using the chips c and b obtained in the above synthesis example, a film was produced using the same film production apparatus as used in Example 1. Chips c and b were separately preliminarily dried and melt-extruded with a single screw extruder A at 280 ° C. ± 2 ° C. while continuously feeding the chip c to the hopper directly above the extruder A with a quantitative screw feeder. (Resin A). The discharge rate of the extruder A was set to 1.004 m ³ / hour (= 1306 kg / hour).

Separately, the chips b were melt-extruded by a single screw extruder B at 255 ° C. ± 2 ° C. (resin B) while being continuously supplied to a hopper directly above the extruder B by a fixed screw feeder. The discharge amount of the extruder B was 0.251 m ³ / hour (= 326 kg / hour). In the extruders A and B, a gear pump in which helical gears having diagonal grooves were arranged in two stages in parallel was used, and the discharge amount was suppressed to a range within an average discharge amount ± 2%.

The resin melted by both extruders was made resin A / resin B = 8/2 (discharge amount ratio), and after passing through the feed block and the static mixer in the same manner as in Example 1, from the T-die It was melt extruded into a film. In this example, the total extrusion amount of the resins A and B was 1.255 m ³ / hour (corresponding to 1632 kg / hour), so the shear rate γ in the mixer was 11.2 (1 / second). It was.

  The extruded resin was electrostatically adhered onto a cooling roll having a surface temperature of 25 ° C. ± 2 ° C. to obtain an unstretched cast film. The rotation speed of the casting roll was controlled by an inverter, and fluctuations in the rotation speed of the casting roll were suppressed within a range of ± 2% within the average speed (62 m / min). The unstretched cast film was preheated in a tenter at 82 ° C. for 24 seconds, subsequently stretched 4.8 times in the transverse direction at 77 ° C., and then heat-treated at 70 ° C. for 24 seconds to obtain a thickness of 45 μm, long A heat-shrinkable polyester film having a thickness of 2000 m or more was obtained. The obtained film was slit into a width of 0.6 m and a length of 2000 m and wound up on a 3-inch paper tube to obtain a film roll. The production conditions are shown in Table 2, and the evaluation results of the obtained film rolls are shown in Tables 4-6. The number of laminated films in Example 2 was 2220.

  In Example 2, when the film was continuously produced, the fluctuation range of the film surface temperature was the average temperature ± 1.0 ° C. in the tenter preheating step, the average temperature ± 1.0 ° C. in the stretching step, and the average in the heat treatment step. The temperature range was ± 1.5 ° C.

Example 3
Using the chips d and e obtained in the above synthesis example, a film was produced with the same film production apparatus as used in Example 1. Chips d and e were separately preliminarily dried, and melt-extruded with a single screw extruder A at 250 ° C. ± 2 ° C. while continuously feeding the chips d to the hopper directly above the extruder A with a fixed screw feeder ( Resin A). The discharge amount of the extruder A was 0.783 m ³ / hour (= 1065 kg / hour). In the extruders A and B, a gear pump in which helical gears having diagonal grooves were arranged in two stages in parallel was used, and the discharge amount was suppressed to a range within an average discharge amount ± 2%.

Separately, the chips e were melt-extruded by a single screw extruder B at 285 ° C. ± 2 ° C. (resin B) while being continuously supplied to a hopper directly above the extruder B by a fixed screw feeder. The discharge amount of the extruder B was 0.522 m ³ / hour (= 710 kg / hour).

The resin melted by both extruders was made resin A / resin B = 6/4 (discharge amount ratio), and after passing through the feed block and the static mixer in the same manner as in Example 1, from the T-die It was melt extruded into a film. In this example, since the total extrusion amount of the resins A and B was 1.305 m ³ / hour (corresponding to 1775 kg / hour), the shear rate γ in the mixer was 11.6 (1 / second). It was.

  The extruded resin was electrostatically adhered onto a cooling roll having a surface temperature of 25 ° C. ± 2 ° C. to obtain an unstretched cast film. The rotation speed of the casting roll was controlled by an inverter, and fluctuations in the rotation speed of the casting roll were suppressed within a range of ± 2% within the average speed (55 m / min). The unstretched cast film was preheated at 60 ° C. with a metal roll as it was, and subsequently stretched longitudinally at 65 ° C. with a silicone rubber roll at 3.2 times. The longitudinally stretched sheet was preheated in a tenter at 82 ° C. for 24 seconds, subsequently stretched 3.8 times in the transverse direction at 90 ° C., and then heat-treated at 210 ° C. for 10 seconds to a thickness of 20 μm and a length of 2000 m. The above biaxially stretched polyester film was obtained. The obtained film was slit into a width of 0.6 m and a length of 2000 m and wound up on a 3-inch paper tube to obtain a film roll. The production conditions are shown in Table 2, and the evaluation results of the obtained film rolls are shown in Tables 4-6. In addition, the number of lamination of the film of Example 3 was 2220.

  In Example 3, when the film was continuously produced, the fluctuation range of the film surface temperature was as follows: the average temperature ± 1.0 ° C. in the tenter preheating step, the average temperature ± 1.0 ° C. in the stretching step, and the heat treatment step. The average temperature was in the range of ± 1.5 ° C.

Example 4
A film was produced with the same film production apparatus used in Example 1. While the pre-dried nylon 6 resin (RV = 2.8: manufactured by Toyobo Co., Ltd.) is continuously fed to the hopper directly above the extruder A with a fixed screw feeder, the single screw extruder A at 245 ° C. ± 2 ° C. Melt extruded (Resin A). The discharge rate of the extruder A was 0.907 m ³ / hour (= 1042 kg / hour).

Separately, while preliminarily dried nylon 66 resin (RV = 3.2: manufactured by Toyobo Co., Ltd.) is continuously fed to the hopper directly above the extruder B with a quantitative screw feeder, a single-screw extruder at 275 ° C. ± 2 ° C. B was melt-extruded (resin B). The discharge amount of the extruder B was 0.389 m ³ / hour (= 447 kg / hour). In the extruders A and B, a gear pump in which helical gears having diagonal grooves were arranged in two stages in parallel was used, and the discharge amount was suppressed to a range within an average discharge amount ± 2%.

  The relative viscosity (RV) of nylon 6 resin and nylon 66 resin was measured according to Section 4.4 of JIS K6920-1 (2000 edition).

Resin melted by both extruders was made resin A / resin B = 7/3 (discharge amount ratio), and after passing through a feed block and a static mixer in the same manner as in Example 1, from the T-die It was melt extruded into a film. In this example, the total extrusion amount of the resins A and B was 1.295 m ³ / hour (corresponding to 1489 kg / hour), so the shear rate γ in the mixer was 11.6 (1 / second). It was.

  The extruded resin was electrostatically adhered onto a cooling roll having a surface temperature of 25 ° C. ± 2 ° C. to obtain an unstretched cast film. The rotation speed of the casting roll was controlled by an inverter, and fluctuations in the rotation speed of the casting roll were suppressed within a range of ± 2% within the average speed (55 m / min). The unstretched cast film was preheated at 50 ° C. with a metal roll as it was, and then stretched longitudinally at a silicone rubber roll at 3.2 times at 55 ° C. The longitudinally stretched sheet was preheated in a tenter at 82 ° C. for 24 seconds, and then stretched 3.8 times in the transverse direction at 100 ° C., followed by heat treatment at 210 ° C. for 10 seconds, thickness 20 μm, length 2000 m. The above biaxially stretched nylon film was obtained. The obtained film was slit into a width of 0.6 m and a length of 2000 m and wound up on a 3-inch paper tube to obtain a film roll. The production conditions are shown in Table 3, and the evaluation results of the obtained film rolls are shown in Tables 4-6. The number of laminated films in Example 4 was 2160.

  In Example 4, when the film was continuously produced, the fluctuation range of the temperature of the film surface was as follows: average temperature ± 1.0 ° C. in the tenter preheating step, average temperature ± 1.0 ° C. in the stretching step, and heat treatment step The average temperature was in the range of ± 1.5 ° C.

Example 5
As extruders A and B, a single-screw extruder having a shaft of 90 mmφ and L / D = 25 was used, respectively, and a static mixer was used with an apparatus having an inner diameter (2r) of 41.2 mm to produce a film. While supplying a pre-dried polypropylene resin (trade name “WF577-PG”; MFR = 3.3; manufactured by Sumitomo Chemical Co., Ltd .; abbreviated as PP in Table 3) continuously to the hopper directly above the extruder A with a quantitative screw feeder. Then, it was melt-extruded with a single screw extruder A at 260 ° C. ± 2 ° C. (Resin A). The discharge amount of the extruder A was 0.16 m ³ / hour (= 148 kg / hour).

Separately, the previously dried polypropylene resin “WF577-PG” and the low density polyethylene resin (trade name “F412” manufactured by Sumitomo Chemical Co., Ltd .; abbreviated as PE in Table 3) are 7: 3 (mass ratio). As described above, while continuously feeding separately to the hopper directly above the extruder B with a fixed screw feeder, mixing in this hopper (abbreviated as PP + PE in the table), and at 275 ° C. ± 2 ° C. with a single screw extruder B Melt extruded (Resin B). The discharge amount of the extruder B was set to 0.16 m ³ / hour (= 148 kg / hour). In the extruders A and B, a gear pump in which helical gears having diagonal grooves were arranged in two stages in parallel was used, and the discharge amount was suppressed to a range within an average discharge amount ± 2%.

Except that a static mixer having an inner diameter (2r) of 41.2 mm was used, the resin melted in both extruders was made to be resin A / resin B = 5/5 (discharge amount ratio) in the same manner as in Example 1. After passing through a feed block and a static mixer, it was melt extruded from a T-die into a film. Since the total extrusion amount of the resins A and B was 0.32 m ³ / hour (corresponding to 295 kg / hour), the shear rate γ in the mixer having an inner diameter of 41.2 mm was 12.9 (1 / second). . The extruded resin was electrostatically adhered onto a cooling roll having a surface temperature of 25 ° C. ± 2 ° C. The rotation speed of the casting roll was controlled by an inverter, and fluctuations in the rotation speed of the casting roll were suppressed within a range of ± 2% within the average speed (120 m / min). An unstretched polypropylene film having a thickness of 60 μm and a length of 2000 m or more was obtained. The obtained film was slit into a width of 0.6 m and a length of 2000 m and wound up on a 3-inch paper tube to obtain a film roll. The production conditions are shown in Table 3, and the evaluation results of the obtained film rolls are shown in Tables 4-6.

  The plastic film wound around the plastic film roll of the present invention has uniform tensile properties and thickness over the entire length of the long film, has no defects in appearance, and has a good finish such as printing and vapor deposition. is there. Therefore, it can be used as a film for various food packaging, general industrial use, optical use, electric material use and molding process. Specifically, for general packaging, antistatic, gas barrier, metal laminating, heat sealing, antifogging, metal deposition, easy tearing, easy opening, bag making packaging, retort packaging, boil packaging, medicine packaging It is suitable for application, easy adhesion, magnetic recording, capacitor, ink ribbon, transfer, adhesive label, stamping foil, gold and silver thread, tracing material, mold release, shrink film and the like.

It is a schematic diagram of the example of an apparatus for implementing this invention method.

Claims (6)

A plastic film roll obtained by winding up a plastic film having a length of 1000 to 7000 m,
The plastic film is prepared by charging two types of resins A and B having different chemical compositions into separate extruders, melting them, joining the melted resins A and B, and passing them through a static mixer. It is obtained by sticking to a cooling roll after extrusion and forming a cast film,
A plastic film roll characterized in that the plastic film satisfies the following requirements (1) to (3).
(1) When the end portion on the winding start side of the film in the steady region where the film physical properties are stable in the length direction of the film is the first end portion, and the end portion on the winding end side is the second end portion, A first sample cutout is provided within 2 m inside the second end, and a final cutout is provided within 2 m inside the first end, and a sample is cut out every about 100 m from the first sample cutout. For each sample cutout part, a film sample with a length of 150 mm in the length direction of the film and a width of 10 mm, and a film sample with a length of 150 mm in the width direction of the film and a width of 10 mm are collected, When the tensile fracture strength in the length direction and the width direction of the film was measured for each sample based on JIS K 7127-1999 at a tensile speed of 100 mm / min, There is within a range within ± 10% of the mean values calculated from them,
(2) When the tensile fracture elongation in the length direction and the width direction of the film was measured in the same manner as described above, the tensile fracture elongation of all samples was within a range of ± 10% of the average value calculated therefrom. In the
(3) A film sample having a length in the length direction of 50 cm and a width of 5 cm was taken for each sample cutout portion in the requirement (1), and the thickness displacement measurement in the length direction was performed on this sample. At each sample cutout portion, the thickness variation defined by the following formula is within a range of 10% or less.
Thickness variation (%) = [(maximum thickness−minimum thickness) / average thickness] × 100 A plastic film roll obtained by winding up a plastic film having a length of 1000 to 7000 m,
The plastic film has two or more layers of the resin A and the layer of the resin B having different chemical compositions, and has 100 layers or more.
A plastic film roll characterized in that the plastic film satisfies the following requirements (1) to (3).
(1) When the end portion on the winding start side of the film in the steady region where the film physical properties are stable in the length direction of the film is the first end portion, and the end portion on the winding end side is the second end portion, A first sample cutout is provided within 2 m inside the second end, and a final cutout is provided within 2 m inside the first end, and a sample is cut out every about 100 m from the first sample cutout. For each sample cutout part, a film sample with a length of 150 mm in the length direction of the film and a width of 10 mm, and a film sample with a length of 150 mm in the width direction of the film and a width of 10 mm are collected, When the tensile fracture strength in the length direction and the width direction of the film was measured for each sample based on JIS K 7127-1999 at a tensile speed of 100 mm / min, There is within a range within ± 10% of the mean values calculated from them,
(2) When the tensile fracture elongation in the length direction and the width direction of the film was measured in the same manner as described above, the tensile fracture elongation of all samples was within a range of ± 10% of the average value calculated therefrom. In the
(3) A film sample having a length in the length direction of 50 cm and a width of 5 cm was taken for each sample cutout portion in the requirement (1), and the thickness displacement measurement in the length direction was performed on this sample. At each sample cutout portion, the thickness variation defined by the following formula is within a range of 10% or less.
Thickness variation (%) = [(maximum thickness−minimum thickness) / average thickness] × 100 It is a manufacturing method of the plastic film roll of Claim 1 or 2, Comprising:
Two types of resins A and B having different chemical compositions were respectively charged into separate extruders A and B, melted, and the melted resins A and B were merged, passed through a static mixer, and extruded from a T-die. When making a cast film by sticking to the cooling roll later,
The ratio ηA / ηB of the melt viscosity ηA of the resin A just before joining and the melt viscosity ηB of the resin B just before joining is 0.5 to 2.0,
A method for producing a plastic film roll, wherein the shear rate γ (1 / second) of the resin in the static mixer is 2 to 100 (1 / second).   The manufacturing method of the plastic film roll of Claim 3 which makes the number of elements of a static mixer 3-18.   The method for producing a plastic film roll according to claim 3 or 4, wherein each discharge amount of the extruders A and B is controlled within a range of an average discharge amount ± 2%.   The manufacturing method of the plastic film roll in any one of Claims 3-5 performed by controlling the rotational speed of a cooling roll in the range of average rotational speed +/- 2%.

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