JP4962108B2 - Polyamide-based mixed resin film roll and method for producing the same - Google Patents

Description

  The present invention relates to a high-quality film roll having uniform physical properties over a long length obtained by winding a polyamide-based mixed resin film. Specifically, it is laminated with a polyolefin-based resin film for packaging retort foods and the like. The present invention relates to a polyamide-based mixed resin film roll having good processability when used.

  Biaxially oriented polyamide resin film mainly composed of nylon is tough and has excellent gas barrier properties, pinhole resistance, transparency, printability, etc., so it can be used for various liquid foods, water-containing foods, frozen foods, It has been widely put into practical use as a packaging material for various foods such as retort foods, pasty foods, livestock meat and fishery foods, and in recent years, it has been widely used for packaging retort foods. Such a polyamide-based resin film is laminated with, for example, a polyolefin-based resin film such as polyethylene or polypropylene, folded in two parallel to the flow direction, then heat-sealed on three sides, and opened on one side. The three-side sealed bag is in a state, filled with various foods and the like, sealed, and then heat-sterilized in boiling water for market.

  However, when a biaxially oriented polyamide-based resin film is used, there is a phenomenon in which the corners of the packaging bag are warped after heat sterilization and the four sides curl into an S shape (hereinafter referred to as an S-curl phenomenon). It may occur and the appearance as a packaged product may be remarkably deteriorated. Therefore, as a method of reducing such curling phenomenon, as in Patent Document 1, the product of boiling water shrinkage strain rate and change rate of molecular orientation angle in the film width direction in a biaxially oriented polyamide resin film is adjusted to a specific value. In order to improve dimensional stability during boiling water treatment, it is necessary to extremely increase the temperature during heat setting or excessively perform relaxation heat treatment after stretching. Therefore, there arises a problem that the toughness and pinhole resistance of the obtained film are impaired.

  Therefore, as described in Patent Document 2, the applicants adjust the boiling water shrinkage and refractive index of the film to a specific numerical range, thereby reducing the S-curl phenomenon without reducing toughness and pinhole resistance. Invented and proposed a method for obtaining a biaxially oriented polyamide-based resin film that does not cause the problem.

Japanese Patent Laid-Open No. 4-103335 JP-A-8-174663

  According to the method of Patent Document 2 described above, it is possible to obtain a biaxially oriented polyamide-based resin film that is tough and excellent in pinhole resistance and does not cause an S-curl phenomenon. However, in the bag making process by lamination, the conditions such as pressure and time when heat-sealing are finely adjusted for each film roll used, so the boiling water shrinkage and refractive index of the film wound around the film roll Even in the case where the average value of physical property values such as is within the range of Patent Document 2, if the amount of fluctuation in one film roll is large, there is a wrinkle between the films when laminating in the bag making process. And troubles such as poor yield are likely to occur.

  On the other hand, in the manufacturing method of a biaxially stretched film roll for winding a biaxially stretched film after mixing and extruding a mixture of a plurality of resins, the applicants as raw material chips Proposed a method for reducing the segregation of the raw material by making the shape of the same and increasing the inclination angle of the funnel-like hopper which is a raw material supply unit to the extruder (Japanese Patent Laid-Open No. 2004-181777). However, this method is not necessarily a definitive method as a method for suppressing fluctuations and variations in physical properties such as boiling water shrinkage and refractive index of a film wound on a film roll.

  Therefore, as a result of earnestly examining the production technology for producing highly uniform biaxially stretched film rolls, the applicants have highly uniform physical properties such as film thickness, boiling water shrinkage rate and refractive index, The inventors have invented a polyamide-based resin film roll that can be formed with a high yield without causing wrinkles between the films when laminating (Japanese Patent Application No. 2004-262922).

  According to the polyamide resin film roll having highly uniform physical properties such as film thickness, boiling water shrinkage and refractive index as described above, the S-curl phenomenon is maintained without deteriorating the good toughness and pinhole resistance of the polyamide resin film. The processability at the time of laminating can be made good without causing the above. However, a film made of only a polyamide-based resin has a limit in pinhole resistance and is not necessarily suitable for packaging foods containing a large amount of water such as liquid soup. Further, as a means for improving the pinhole resistance of a polyamide resin film, a method of filling an elastomer into a polyamide resin which is a film raw material is known. In such a mixed resin film roll, It is not possible to obtain good processability at the time of laminating simply by reducing the variation in physical properties such as thickness, boiling water shrinkage and refractive index, and there is variation in pinhole resistance in each laminated three-sided seal bag. It will occur.

  The present invention has been achieved as a result of earnest research and development on production technology for making a biaxially stretched mixed resin film composed of a mixed resin of a polyamide-based resin and an elastomer highly uniform. , Which eliminates the problems of conventional polyamide resin film rolls and can be used in packaging applications that require extremely high pinhole resistance. An object of the present invention is to provide a biaxially oriented polyamide mixed resin film roll capable of efficiently obtaining a package having no S-curl. Another object of the present invention is to provide a biaxially oriented polyamide mixed resin film roll capable of obtaining a processed product with a high yield in post-processing such as bag making processing. In addition, it is providing the manufacturing method which can manufacture such a biaxially-oriented polyamide type mixed resin film roll efficiently.

Among the present inventions, the invention described in claim 1 is formed by melt-extruding a mixed resin of nylon 6 and a polyamide-based elastomer or a polyolefin-based elastomer and then biaxially stretching, and has a width of 0. A film roll formed by winding a film having a length of 2 m or more and 3.0 m or less and a length of 300 m or more and 30000 m or less, and the amount of polyamide-based elastomer or polyolefin-based elastomer added to nylon 6 is 3 wt% or more and 10 wt% %, And the biaxial stretching is performed in two stages in the longitudinal direction and then in the transverse direction, and the first longitudinal stretching is performed at 2.0 to 2 at a temperature of 80 to 90 ° C. is intended to .4 times stretching, longitudinal stretching of the two-stage, which is stretched 1.3 to 1.7 times at a temperature of 65 to 75 ° C., and yet, The longitudinal stretching ratio of the second stage is higher than the longitudinal stretching ratio of the second stage, and the first sample cutout portion is within 2 m from the end of film winding, and the final cutout is within 2 m from the beginning of film winding. When the sample cutout portion is provided every 100 m from the first sample cutout portion, the following requirements (a) to (c) are satisfied.
(A) When the tensile modulus in the film winding direction is measured for each sample cut out from each cut-out portion, the average tensile modulus, which is the average value of the tensile modulus, is 1.30 GPa or more 2 (B) For each sample cut out from each cut-out part, the variation rate of the tensile elastic modulus of all the samples is within ± 10% of the average tensile elastic modulus. measuring the content of the thermoplastic elastomer component, when calculating the average content which is the average value of their content, of all the samples, the difference between the content and the average content of the thermoplastic elastomer component The variation rate of the largest sample is within the range of ± 2% to ± 10% with respect to the average content rate. (C) The average thickness among the maximum and minimum thicknesses in the longitudinal direction of the wound roll. Difference from Larger variation rate is in the range of from ± 2% ~ ± 10% relative to the average thickness

The invention described in claim 2 is the invention described in claim 1, wherein each sample cut out from each cut-out part is continuously used at a rate of 40 cycles per minute using a gelbo flex tester. In this case, the number of pinholes when the bending test of 3000 cycles is performed is 10 pieces / 497 cm ² or less in all cases.

The invention described in claim 3 is the invention described in claim 1, wherein the maximum boiling water shrinkage rate, which is the maximum value among the boiling water shrinkage rates in all directions, is determined for each sample cut out from each cutout portion. When measured, the average boiling water shrinkage, which is the average value of the maximum boiling water shrinkage, is 3% to 6%, and among all the samples, the difference between the maximum boiling water shrinkage and the average boiling water shrinkage is the largest. The variation rate of the large sample is characterized by being in the range of ± 2% to ± 10% with respect to the average boiling water shrinkage rate .

The invention described in claim 4 is the invention described in claim 1, wherein the boiling water shrinkage in the direction of +45 degrees with respect to the longitudinal direction and −45 with respect to the longitudinal direction of each sample cut out from each of the cutout portions. When the boiling water shrinkage direction difference, which is the absolute value of the difference between the boiling water shrinkage rate in the direction of temperature, is determined, the average boiling water shrinkage direction difference, which is the average value of the boiling water shrinkage direction differences, is 1.5% or less. In addition, among all the samples, the variation rate of the sample having the largest difference between the boiling water shrinkage direction difference and the average boiling water shrinkage direction difference is ± 2% to ± 10% with respect to the average boiling water shrinkage direction difference. It is characterized by being within the range .

  The configuration of the invention described in claim 5 is that, in the invention described in claim 1, when the refractive index in the thickness direction is measured for each sample cut out from each cutout portion, the average of those refractive indexes is measured. The average refractive index as a value is 1.500 or more and 1.520 or less, and the variation rate of the refractive index of all the samples is within a range of ± 2% with respect to the average refractive index.

  The structure of the invention described in claim 6 is that, in the invention described in claim 1, the main component of the polyamide-based resin is nylon 6.

  The structure of the invention described in claim 7 is that, in the invention described in claim 1, the main component of the thermoplastic elastomer is at least one of a polyamide-based elastomer and a polyolefin-based elastomer.

The structure of the invention described in claim 6 is that, in the invention described in claim 1, the wound polyamide-based mixed resin film is laminated with the polyolefin-based resin film.

The structure of the invention described in claim 7 is the non-oriented obtained in the invention described in claim 1 by extruding the molten polyamide-based mixed resin from the T-die and bringing it into contact with a metal roll and cooling it. That is, a polyamide-based mixed resin film obtained by biaxially stretching the sheet-like material is wound up.

The structure of the invention described in claim 8 is that in the invention described in claim 1, a polyamide-based mixed resin film stretched by a tenter stretching method is wound.

The structure of the invention described in claim 9 is that, in the invention described in claim 1, the polyamide-based mixed resin film that has been sequentially biaxially stretched is wound.

The structure of the invention described in claim 10 is that in the invention described in claim 1, a polyamide-based mixed resin film stretched biaxially in the vertical direction and the horizontal direction is wound.

The structure of the invention described in claim 11 is the glass transition of the main component of the polyamide-based mixed resin in the invention described in claim 1 in which a sheet-like material made of a substantially unoriented polyamide-based mixed resin is used. A polyamide-based mixed resin film that is stretched in the longitudinal direction in at least two stages so as to obtain a magnification of 3 times or more at a temperature higher than the temperature + 20 ° C. and then stretched in the transverse direction so as to obtain a magnification of 3 times or more. It is that it is wound up.

The structure of the invention described in claim 12 is that, in the invention described in claim 1, the polyamide-based mixed resin film which is heat-set after the final stretching treatment is wound up.

The structure of the invention described in claim 13 is that in the invention described in claim 1, a polyamide-based mixed resin film which has been subjected to relaxation treatment after heat setting is wound.

In the invention described in claim 14 , in the invention described in claim 1, in the polyamide-based mixed resin film wound up, a lubricant, an anti-blocking agent, a heat stabilizer, an antioxidant, an antistatic agent are used. This is because at least one of an agent, a light resistance agent, and an impact resistance improvement agent is added.

The structure of the invention described in claim 15 is that, in the invention described in claim 1, inorganic particles are added to the wound polyamide-based mixed resin film.

The structure of the invention described in claim 16 is that, in the invention described in claim 15 , the inorganic particles are silica particles having an average particle diameter of 0.5 to 5.0 μm.

The structure of the invention described in claim 17 is that, in the invention described in claim 1, a higher fatty acid is added to the wound polyamide-based mixed resin film.

The structure of the invention described in claim 18 is a film-forming step of forming a film made of melt-extruded chips made of nylon 6 and a chip made of polyamide-based elastomer or polyolefin-based elastomer, and unstretched obtained in the film-forming step To produce a polyamide-based mixed resin film roll according to claim 1, comprising a biaxial stretching step of biaxially stretching the film in the machine direction and the transverse direction, and a roll forming step of winding up the biaxially stretched film. The following manufacturing method (5) satisfies the following requirements (1) to (5).
(1) The film forming step is to melt and extrude after mixing nylon 6 chip and polyamide elastomer chip or polyolefin elastomer chip, and the shape of each chip used has a major axis and a minor axis The shape is an elliptic cylinder having an elliptical cross section, and the polyamide elastomer chip or the polyolefin elastomer chip is within ± 20% of the average major axis, average minor axis, and average chip length of the nylon 6 chip. (2) The film forming step is performed by melt extrusion after mixing the nylon 6 chip and the polyamide-based elastomer chip or the polyolefin-based elastomer chip in the film having the average major axis, the average minor axis, and the average chip length. To be , Mixing of the nylon 6 chips and polyamide elastomer chips or polyolefin elastomer chips, performed by adding a sublimable segregation inhibitor (3) the film of step is provided with a funnel-shaped hopper as a raw material chip supply unit A step of melt extrusion using an extruder, the inclination angle of the hopper being adjusted to 65 degrees or more, and a nylon 6 chip and a polyamide-based elastomer chip or polyolefin-based before being supplied to the hopper The moisture content of the elastomer chip is adjusted to 800 ppm or more and 1000 ppm or less, and the temperature of the nylon 6 chip and the polyamide elastomer chip or the polyolefin elastomer chip before being supplied to the hopper is adjusted to 80 ° C. or more ( 4) The above two The axial stretching step includes a preheating step that is performed before the stretching in the longitudinal direction and a heat treatment step that is performed after the stretching in the longitudinal direction. The fluctuation range of the surface temperature of the film at an arbitrary point in the stretching process is adjusted within the range of the average temperature ± 1 ° C. over the entire length of the film. (5) The film forming process is melted extruded from the extruder. A roll cooling step for cooling the resin by winding the resin around a cooling roll, and in the roll cooling step, the portion that contacts the surface of the molten resin and the cooling roll extends over the entire width of the molten resin. Is sucked in the direction opposite to the winding direction.

  According to the polyamide-based mixed resin film roll of the present invention, even when a bag making process of a three-side sealed bag for packaging liquid soup or the like that requires a high degree of pinhole resistance is performed, it is laminated smoothly with almost no trouble. Thus, it is possible to efficiently obtain a package having no S-curl. Further, in post-processing such as bag making processing, a processed product can be obtained with a high yield. In addition, if the polyamide-based mixed resin film roll of the present invention is used, the bag for food packaging after the bag-making process by lamination has a very high pinhole resistance, and the pin resistance for each bag. Hall variation is reduced.

  In addition, according to the method for producing a polyamide-based mixed resin film roll of the present invention, a polyamide-based mixed resin film roll having extremely high pinhole resistance and good laminating properties is inexpensive and extremely efficient. Can be obtained.

  The polyamide-based mixed resin film roll of the present invention cuts out a sample by a method to be described later, measures the content of the thermoplastic elastomer component for each cut out sample, and calculates the average content that is the average of those contents. When calculated, it is necessary that the variation rate of the content of the thermoplastic elastomer component in all the samples is within a range of ± 10% with respect to the average content rate.

  In the cutting of the sample in the present invention, first, the first sample cutting portion is provided within 2 m from the end of winding of the film, and the final cutting portion is provided within 2 m from the beginning of winding of the film. A sample cut-out section is provided every about 100 m. Note that “about every 100 m” means that the sample may be cut out at about 100 m ± 1 m.

  More specifically, the cutting of the above sample will be described. For example, when a polyamide-based film having a length of 498 m is wound around a roll, the first sample (1) is taken within 2 m from the end of winding of the film. cut out. For convenience, the sample is cut out in a rectangular shape so as to have a side along the longitudinal direction of the film and a side along the direction orthogonal to the longitudinal direction (not cut diagonally). Subsequently, the second sample (2) is cut away from the cut portion at a distance of 100 m from the winding start side. In the same manner, the third sample (3) is separated to the winding start side of 200 m, the fourth sample (4) is separated to the winding start side of 300 m, and the fifth sample is separated to the winding start side of 400 m. Cut out (5). When the sample is cut out in this way, the remainder becomes shorter than 100 m, so the sixth (final) sample (6) cuts out any portion within 2 m from the start of film winding.

  And, for each sample cut out, the content of the thermoplastic elastomer component is quantitatively analyzed, and when the average content rate, which is the average value of those content rates, is calculated, the content of the thermoplastic elastomer component in all the samples That is, it is necessary that the fluctuation rate of the above is within a range of ± 10% with respect to the average content rate. Here, the variation rate of the thermoplastic elastomer component content of all the samples is the maximum / minimum of the thermoplastic elastomer component content (measured value) of all the samples. It means the ratio of the difference with respect to the average content when the difference between the average content and the one with the larger difference from the average content is obtained. As will be described later, the content of the thermoplastic elastomer component is sliced perpendicular to the surface to form an ultrathin piece, and the elastomer component is dyed with a specific substance to occupy the entire dyed portion. It can be measured by a method of calculating the area ratio, or can be measured by other methods such as infrared analysis and NMR analysis focusing on a peak peculiar to the elastomer.

  The polyamide-based mixed resin film roll of the present invention preferably has a variation rate of the elastomer component content of all cut out samples within a range of ± 9% of the average content, and within a range of ± 8%. More preferably, it is more preferably within the range of ± 7%.

  In addition, the polyamide-based mixed resin film roll of the present invention is preferably as small as the variation rate of the elastomer component content of all cut out samples, but the lower limit of the variation rate is about 2% in consideration of measurement accuracy. I think it is the limit.

Moreover, the polyamide-based mixed resin film roll of the present invention has an average tensile elastic modulus of 1. as the average value of the tensile elastic modulus when the tensile elastic modulus is measured for each sample cut out from each cut-out portion. 30GPa with less than (1300N / mm ²⁾ or more 2.50GPa (2500N / mm ^2), tensile modulus change rate of all samples, adjusted within a range of ± 10% relative to the average tensile elastic modulus Preferably. Here, the fluctuation rate of the tensile modulus of elasticity of all the samples is the maximum / minimum of the tensile modulus of elasticity of all the samples, and the larger of the difference between the average tensile modulus of the maximum / minimum It means the ratio of the difference to the average tensile elastic modulus when the difference from the average tensile elastic modulus is obtained.

  In addition, the tensile elastic modulus of the polyamide-based mixed resin film constituting the polyamide-based mixed resin film roll is important in increasing the toughness and pinhole resistance of the film itself, and when the tensile elastic modulus is less than 1.30 GPa, On the other hand, if the toughness and pinhole resistance are insufficient, and if it exceeds 2.50 GPa, tearing properties are deteriorated when a three-side sealed bag is formed, it is not preferable. A more preferable range of the tensile elastic modulus is 1.50 GPa to 2.30 GPa in order to enhance toughness / pinhole resistance and tearability when forming a three-side sealed bag.

  In the polyamide-based mixed resin film roll of the present invention, the variation rate of the tensile modulus of all cut out samples is preferably within ± 9% of the average tensile modulus, and within ± 8%. More preferably, it is more preferably within a range of ± 7%.

  In addition, the polyamide-based mixed resin film roll of the present invention is preferably as small as the variation rate of the tensile modulus of all the cut out samples, but the lower limit of the variation rate is limited to about ± 2% in consideration of measurement accuracy. I believe that.

  In addition, the polyamide-based mixed resin film roll of the present invention is continuously 3000 cycles at a rate of 40 cycles per minute using a gelbo flex tester for each sample cut out from each cut-out portion by the following method. It is preferable that the number of pinholes in the bending test is adjusted so as to be 10 or less.

[Measurement method of pinhole resistance]
A film laminated with a polyolefin film or the like and cut to a predetermined size (20.3 cm x 27.9 cm) is conditioned at a predetermined temperature and humidity for a predetermined time, and then the rectangular test film is wound. To form a cylindrical shape having a predetermined length. Then, both ends of the cylindrical film are fixed to the outer periphery of the disk-shaped fixed head of the gel bow flex tester and the outer periphery of the disk-shaped movable head, respectively, and the movable heads are parallel to the direction of the fixed head. Rotate a predetermined angle (440 °) while approaching a predetermined length (7.6 cm) along the axis, and then proceed straight ahead for a predetermined length (6.4 cm) without rotating, then reverse their movements A one-cycle bending test in which the movable head is returned to the initial position by being executed in the direction is continuously repeated for a predetermined cycle (3000 cycles) at a predetermined speed (40 cycles per minute). Thereafter, the number of pinholes generated in a predetermined range (497 cm ² ) excluding a fixed portion of the tested film and a portion fixed to the outer periphery of the movable head is measured.

  In addition, when the polyamide-based mixed resin film roll of the present invention is cut out by the method described later, the maximum boiling water shrinkage which is the maximum value of the boiling water shrinkage in all directions is measured for all samples by the following method. When the rate is measured, it is preferable that the average boiling water shrinkage, which is the average value of the maximum boiling water shrinkage, is adjusted to be 3% or more and 6% or less.

  Moreover, when the polyamide-based mixed resin film roll of the present invention is cut out by the method described later, the boiling water shrinkage rate in the +45 degree direction with respect to the longitudinal direction and the longitudinal direction are measured for all the samples by the following method. When the boiling water shrinkage direction difference, which is the absolute value of the difference from the boiling water shrinkage rate in the -45 degree direction, was determined, the average boiling water shrinkage direction difference, which is the average of the boiling water shrinkage direction differences, was 1.5%. It is preferable to adjust so as to be as follows.

[Measuring method of boiling water shrinkage (BS), maximum boiling water shrinkage (BSx), average boiling water shrinkage (BSax), boiling water shrinkage direction difference (BSd), average boiling water shrinkage direction difference (BSad)]
The biaxially oriented polyamide-based resin film cut out from each cut-out portion of the polyamide-based resin film roll is cut into a square shape and left in an atmosphere of 23 ° C. and 65% RH for 2 hours or more. A circle (about 20 cm in diameter) centered on the center of this sample is drawn, and a straight line passing through the center of the circle in the direction of 0 to 165 ° clockwise at 15 ° intervals, with the vertical direction (film drawing direction) being 0 °. Pull, measure the diameter in each direction, and make it the length before processing. The cut sample was then heat-treated in boiling water for 30 minutes, then removed and wiped off the moisture adhering to the surface, air-dried, and left in an atmosphere of 23 ° C. and 65% RH for 2 hours or more, as described above. The length of the straight line drawn in each diametric direction is measured and set as the length after treatment. BS (boiling water shrinkage), BSx (maximum boiling water shrinkage), BSax (average boiling water shrinkage), BSd (boiling water shrinkage direction difference) and BSad (average boiling water shrinkage direction difference) are calculated.
BS = [(length before processing−length after processing) / length before processing] × 100 (%)... 1
BSx = Maximum shrinkage rate (%) measured in 0 to 165 ° direction at 15 ° intervals 2
BSax = sum of BSx of all samples / number of samples 3
BSd = | (BS in 45 ° direction) − (BS in 135 ° direction) |
BSad = sum of BSd of all samples / number of samples 5

  The value of BSx of the polyamide-based mixed resin film constituting the polyamide-based mixed resin film roll is the heat resistance (lamination strength or heat resistance) when the biaxially oriented polyamide-based resin film is formed into a bag shape and subjected to hot water treatment. It is important to ensure the toughness and pinhole resistance of the film itself, and if the BSx value is less than 3%, the toughness and pinhole resistance will be insufficient. If it exceeds 6%, it is not preferable because poor lamination or insufficient heat-resistant laminate strength during hot water treatment may result. The range of BSx that is more preferable for enhancing toughness, pinhole resistance, laminating properties, and heat-resistant laminating strength is 3.5 to 5.0%.

  Also, the BSd value of the polyamide-based mixed resin film constituting the polyamide-based mixed resin film roll has a great influence on the curling phenomenon that occurs during the boiling water treatment, and the larger the BSd value, the easier the bag will bend and the curling becomes remarkably. However, if BSd is suppressed to 1.5% or less, more preferably 1.2% or less, the bag warpage during boiling water treatment can be suppressed as much as possible, and the occurrence of the S-curl phenomenon can be prevented. It becomes possible.

  Further, in the polyamide-based mixed resin film roll of the present invention, the variation rate of the maximum boiling water shrinkage (BSx) of all the cut out samples is ± 2% to ± 10% (± 2%) of the average boiling water shrinkage (BSa). It is preferable to adjust so as to be within the range of ± 10% or less. Here, the variation rate of the maximum boiling water shrinkage (BSx) of all the samples is the maximum / minimum of the maximum boiling water shrinkage (BSx) of all the samples, and the average boiling water shrinkage of those maximum / minimum. It means the ratio of the difference with respect to the average boiling water shrinkage when the difference between the one with the larger difference between the ratio and the average boiling water shrinkage is obtained.

  That is, in the polyamide-based mixed resin film roll of the present invention, when the boiling water shrinkage rate of the samples (1) to (6) is Xn (n = 1 to 6), the maximum value Xmax of Xn and the average boiling water shrinkage rate. This means that both the difference from (BSax) and the difference between the minimum value Xmin and the average boiling water shrinkage (BSax) must be within ± 10%. BSax-Xn | (where || indicates an absolute value) is preferably 10% or less.

  In the polyamide-based mixed resin film roll of the present invention, the variation rate of the maximum boiling water shrinkage (BSx) of all cut out samples is more preferably within ± 9% of the average boiling water shrinkage (BSa). , More preferably within a range of ± 8%, and even more preferably within a range of ± 7%.

  In addition, the polyamide-based mixed resin film roll of the present invention is preferably as small as the variation rate of the maximum boiling water shrinkage (BSx) of all the cut out samples, but the lower limit of the variation rate is ± 2 in consideration of measurement accuracy. % Is considered the limit.

  Further, in the polyamide based mixed resin film roll of the present invention, the fluctuation rate of the boiling water shrinkage direction difference (BSd) of all the cut out samples is ± 2% to ± 10% of the average boiling water shrinkage direction difference (BSad) ( It is preferable to adjust so as to be within a range of ± 2% or more and ± 10% or less. Here, the fluctuation rate of the boiling water shrinkage direction difference (BSd) of all the samples is the maximum / minimum in the boiling water shrinkage direction difference (BSd) of all the samples, and the average of these maximum / minimum values. When the difference between the larger difference between the boiling water shrinkage direction difference and the average boiling water shrinkage direction difference is obtained, it means the ratio of the difference to the average boiling water shrinkage direction difference.

  That is, in the polyamide-based mixed resin film roll of the present invention, when the boiling water shrinkage direction difference of samples (1) to (6) is Yn (n = 1 to 6), the maximum value Ymax of Yn and the average boiling water The difference between the difference in shrinkage direction (BSad) and the difference between the minimum value Ymin and the average boiling water shrinkage direction difference (BSad) must be within ± 10%. In other words, | BSad-Yn | (where || indicates an absolute value) is preferably 10% or less.

  In the polyamide mixed resin film roll of the present invention, the fluctuation rate of the boiling water shrinkage direction difference (BSd) of all the cut out samples is within a range of ± 9% of the average boiling water shrinkage direction difference (BSad). And more preferably within a range of ± 8%, and further preferably within a range of ± 7%.

  In addition, the polyamide-based mixed resin film roll of the present invention is preferably as the fluctuation rate of the boiling water shrinkage direction difference (BSd) of all the cut out samples is smaller, but the lower limit of the fluctuation rate is ± We think about 2% is the limit.

  In the polyamide-based mixed resin film roll of the present invention, the variation rate of the thickness over the entire length in the longitudinal direction is within a range of ± 2% to ± 10% (± 2% or more and ± 10% or less) with respect to the average thickness. It is necessary to be adjusted so that Here, the variation rate of the thickness over the entire length in the longitudinal direction is the maximum / minimum of the thickness over the entire length in the longitudinal direction, and the difference between the average thickness of the maximum / minimum average thickness and the average thickness It means the ratio of the difference to the average thickness when the difference is obtained.

  That is, in the polyamide-based mixed resin film roll of the present invention, the difference between the maximum value Tmax of the thickness over the entire length in the longitudinal direction and the average thickness (the average thickness Ta over the entire length in the longitudinal direction), and the minimum value Tmin and the average thickness (Ta ) Is required to be within ± 10%.

  In the polyamide-based mixed resin film roll of the present invention, the variation rate of the thickness over the entire length in the longitudinal direction is preferably within ± 8% of the average thickness (Ta), and within ± 6%. More preferred.

  In addition, the polyamide-based mixed resin film roll of the present invention is preferable as the variation rate of the thickness over the entire length in the longitudinal direction is small, but the lower limit of the variation rate is about ± 2% from the viewpoint of the performance of the film forming apparatus. I think there is.

Furthermore, when the polyamide-based mixed resin laminated film roll of the present invention is cut out by the above method, when the refractive index (Nz) in the thickness direction is obtained for all the samples, the average value of the refractive indexes is obtained. The average refractive index (Nza) is preferably adjusted to be 1.500 or more and 1.520 or less. The average refractive index is calculated by the following formula 6.
Nza = total Nz of all samples / number of samples 6

  In addition, the value of Nz of the polyamide film constituting the polyamide-based mixed resin laminated film roll has a great influence on the film quality such as laminate strength and thickness unevenness. Therefore, the requirement that the average refractive index is 1.500 or more and 1.520 or less is an indispensable requirement when the biaxially oriented polyamide resin film is laminated with the polyolefin resin film. When Nz is less than 1.500, the laminate strength with the polyolefin resin film or the like becomes insufficient, and peeling between the laminate base material is likely to occur due to boiling water treatment after bag making. On the other hand, this Nz gradually decreases in the process of biaxially stretching an unstretched polyamide resin film. In other words, Nz can also be considered as one of the indices of stretching, and a large Nz indicates that stretching is insufficient. If Nz exceeds 1.520, it is due to insufficient biaxial stretching. Thick spots and the like appear remarkably, and satisfactory film quality cannot be obtained. Considering both the laminate strength and the film quality, a particularly preferable range of Nz is in the range of 1.507 to 1.516.

  Further, in the polyamide-based mixed resin laminated film roll of the present invention, the variation rate of the refractive index (Nz) of all the cut out samples is ± 2 with respect to the average value of the refractive indexes (hereinafter referred to as the average refractive index). It is preferable to adjust so that it may become in the range within%. Here, the variation rate of the refractive index (Nz) of all the samples is the maximum / minimum of the refractive indexes (Nz) of all the samples, and the difference between the average refractive index of the maximum / minimum values. When the difference between the larger one and the average refractive index is obtained, it means the ratio of the difference to the average refractive index.

  That is, in the polyamide-based mixed resin laminated film roll of the present invention, when the refractive indexes of the samples (1) to (6) are Nz1 to Nz6, the difference between the maximum value Nzmax of Nz1 to Nz6 and the average refractive index , Nz1 to Nz6, and the difference between the minimum value Nzmin and the average refractive index is preferably within ± 2%, in other words, | average refractive index−Nz1 | ˜ | average refractive index. -Nz6 | is preferably 2% or less. In the polyamide-based mixed resin laminated film roll of the present invention, it is more preferable that the variation rate of the refractive index (Nz) of all the cut out samples is within a range of ± 1% with respect to the average refractive index.

  In addition, the polyamide-based mixed resin laminated film roll of the present invention is preferable as the variation rate of the refractive index (Nz) of all the cut out samples is smaller. However, the lower limit of the variation rate is from the viewpoint of measurement accuracy and mechanical accuracy. About 0.1% is considered the limit.

  As described above, 3 for packaging liquid soup or the like that requires high pinhole resistance by reducing fluctuations in the elastomer component content and film thickness in one polyamide-based mixed resin film roll. Even when carrying out the bag-making process of the side-sealed bag, it is possible to prevent the deterioration of the appearance in the bag-making process and the laminating process, and it is possible to process it smoothly with a high yield.

  Examples of the polyamide resin used in the present invention include nylon 6 using ε-caprolactam as a main raw material. Examples of other polyamide resins include polyamide resins obtained by polycondensation of lactams having three or more members, ω-amino acids, dibasic acids and diamines. Specifically, as lactams, in addition to the above-mentioned ε-caprolactam, enantolactam, capryllactam, lauryllactam, and ω-amino acids include 6-aminocaproic acid, 7-aminoheptanoic acid, 9- Examples include aminononanoic acid and 11-aminoundecanoic acid. Examples of dibasic acids include adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecadioic acid, hexadecadioic acid, eicosandioic acid, eicosadienedioic acid, 2 2,4-trimethyladipic acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and xylylenedicarboxylic acid. Furthermore, as diamines, ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, pentamethylenediamine, undecamethylenediamine, 2,2,4 (or 2,4,4) -trimethylhexamethylenediamine, cyclohexane Examples thereof include diamine, bis- (4,4′-aminocyclohexyl) methane, and metaxylylenediamine. And polymers obtained by polycondensation of these or copolymers thereof, such as nylon 6, 7, 11, 12, 6.6, 6.9, 6.11, 6.12, 6T, 6I, MXD6 (Metaxylene dipanamid 6), 6 / 6.6, 6/12, 6 / 6T, 6 / 6I, 6 / MXD6, and the like can be used. In addition, when producing the polyamide-based mixed resin film roll of the present invention, the above-mentioned polyamide resins can be used alone or in admixture of two or more.

  Of the polyamide-based resins, those having a relative viscosity in the range of 2.0 to 3.5 are particularly preferable in the present invention. The relative viscosity of the polyamide-based resin affects the toughness and spreadability of the resulting biaxially stretched film. If the relative viscosity is less than 2.0, the impact strength tends to be insufficient. This is because, if it exceeds 3.5, the biaxial stretchability tends to deteriorate with increasing stretching stress. In addition, the relative viscosity in this invention means the value at the time of measuring at 25 degreeC using the solution which melt | dissolved 0.5g of polymers in 50 ml of 97.5% sulfuric acid.

  Examples of the thermoplastic elastomer used in the present invention include a polyamide such as a block or random copolymer of a polyamide-based resin such as nylon 6 or nylon 12 and PTMG (polytetramethylene glycol) or PEG (polyethylene glycol). It is preferable to use a polyolefin-based elastomer, an ethylene-methacrylic acid copolymer, a copolymer of ethylene and butene, a polyolefin-based elastomer such as a copolymer of styrene or butadiene, or an ionomer of an olefin-based resin such as an ethylene-based ionomer. it can.

  Further, the amount of the thermoplastic elastomer added to the polyamide resin is not particularly limited, but the lower limit of the addition amount is preferably 1% by weight or more, more preferably 2% by weight or more. More preferably, it is at least wt%. On the other hand, the upper limit of the addition amount is preferably 15% by weight or less, more preferably 10% by weight or less, and further preferably 6% by weight or less. If the added amount of the thermoplastic elastomer is less than 1% by weight, it is not preferable because good pinhole resistance cannot be obtained. Conversely, if the added amount of the thermoplastic elastomer exceeds 15% by weight, the toughness of the film is reduced. It is not preferable because it is damaged.

  Next, the preferable manufacturing method for obtaining the polyamide-type resin film roll of this invention is demonstrated. The polyamide-based resin film roll of the present invention is formed into a roll after biaxially stretching an unstretched film obtained by melting and extruding a raw material polyamide resin chip in the longitudinal direction (longitudinal direction) and the transverse direction (width direction). Manufactured by winding.

  As a result of examining the thickness variation in the vertical direction of the film roll (thickness variation over the entire length of the film roll) and variation in physical properties such as boiling water shrinkage rate and variations, the present inventors have found that the thickness variation in the vertical direction and the variation in physical properties. It has been found that variations and variations are largely influenced by various factors in the casting process in which a molten resin is converted into an unstretched film. That is, if the temperature of the resin when supplied to a funnel-shaped popper directly connected to the extruder (hereinafter simply referred to as a hopper) is low or the moisture content of the resin supplied to the hopper is high, the thickness in the longitudinal direction of the unstretched film It was found that the spots became larger, and the fluctuations and variations in physical properties of the biaxially stretched film increased. In addition, when the resin extruded from the T die is wound around a metal roll, even if the contact point between the resin and the metal roll is disturbed, the thickness unevenness in the longitudinal direction in the unstretched film becomes large, and the physical properties in the biaxially stretched film It was found that the fluctuation and variation of Furthermore, it was also found that if the stretching conditions in the biaxial stretching process are inappropriate, the thickness unevenness in the longitudinal direction of the unstretched film is amplified, which promotes fluctuations and variations in physical properties.

Furthermore, as a result of intensive studies based on the above facts, the present inventors have found out that it is possible to obtain a film roll with little fluctuation in physical properties by taking the following means when manufacturing the film roll. It was.
(1) Unification of shape of polyamide resin chip and elastomer chip (2) Reduction of moisture content when resin chip is dried (3) Temperature retention when resin is supplied to hopper (4) Optimization of hopper shape (5) Resin Addition of anti-segregation agent during mixing (6) Removal of adverse effects due to addition of anti-segregation agent (7) Optimization of stretching conditions Hereinafter, each of the above-described means will be sequentially described.

(1) Unification of the shape of the polyamide-based resin chip and the elastomer chip In the manufacture of the polyamide-based mixed resin film roll of the present invention, the polyamide resin chip and the elastomer chip as raw materials are blended in a hopper, and then melt-kneaded. Extruded from an extruder to form a film (so-called blending method). That is, the polyamide-based resin chip and the elastomer chip are supplied continuously or intermittently in separate hoppers, and finally passed through a buffer hopper as necessary, finally, a hopper immediately before or just above the extruder (hereinafter referred to as “ While mixing the polyamide resin chip and the elastomer chip in the final hopper), the raw material chips are quantitatively supplied to the extruder according to the extrusion amount of the extruder to form a film.

  However, depending on the capacity or shape of the final hopper, when the amount of chips in the final hopper is large and the remaining amount of chips in the final hopper is small, the material segregation phenomenon, that is, from the final hopper to the extruder. A phenomenon occurs in which the composition of the supplied chip is different. Further, such segregation phenomenon appears particularly prominent when the shape or specific gravity of the chip is different. Furthermore, due to such segregation phenomenon, when a long film is produced, the tensile elastic modulus, pinhole resistance, maximum boiling water shrinkage rate, boiling water shrinkage direction difference, film thickness, and refractive index in the thickness direction vary.

  That is, if there is a difference between the size of the polyamide resin chip and the size of the elastomer chip, when the mixture of chips falls in the final hopper, small chips tend to fall first, so that the chip residue in the final hopper remains. As the amount decreases, the ratio of large chips increases, which causes raw material segregation. Therefore, in order to obtain a film roll with little variation in physical properties, it is necessary to match the shapes of the polyamide resin chip and the elastomer chip to suppress the phenomenon of raw material segregation in the final hopper.

  Polyamide raw material chips are usually formed in a molten state after polymerization in the form of strands from a polymerization apparatus, immediately cooled with water, and then cut with a strand cutter. For this reason, the polyamide chip has an elliptical column shape with an elliptical cross section. On the other hand, elastomer raw material chips are often formed in a disk shape having an elliptical cross section, and as a result of examining the relationship between the shape of polyamide chips and elastomer chips and raw material segregation, The average major axis (mm), average minor axis (mm), and average chip length (mm) are the average major axis (mm), average minor axis (mm), and average chip length of the cross-sectional ellipse of the polyamide resin raw material chip, respectively. The raw material segregation can be reduced by adjusting the thickness (mm) within a range of ± 25%. The average major axis, average minor axis, and average chip length of the cross-sectional ellipse of the elastomer chip are within ± 20% of the average major axis, average minor axis, and average chip length of the cross-sectional ellipse of the polyamide resin chip, respectively. Adjusting to the range is more preferable because the effect of preventing segregation becomes extremely remarkable.

(2) Moisture reduction during resin chip drying Chips supplied into the hopper are usually heated and reduced in water by an apparatus such as a blender. When drying such a chip, in the production of a polyester film roll or a polypropylene film roll, it is generally considered that the lower the moisture content during drying, the less hydrolysis in the extrusion process and the better the film roll is obtained. ing. However, as a result of studies by the present inventors, in the production of a polyamide-based resin film roll, it is difficult to stretch simply by lowering the moisture content during drying, and a film roll having uniform physical properties can be obtained. First, it was found that a film roll with uniform physical properties can be obtained by controlling the moisture content within a predetermined range and securing a certain amount of moisture so as to be appropriately plasticized without being hydrolyzed in the extrusion process. . That is, in order to obtain the film roll of the present invention, it is necessary to control the moisture content of the chip to 800 ppm or more and 1000 ppm or less. When the moisture content of the chip exceeds 1000 ppm, hydrolysis is promoted when it is melted, the viscosity is lowered, the thickness unevenness in the longitudinal direction of the unstretched film is deteriorated, and the thickness unevenness in the longitudinal direction of the biaxially stretched film is deteriorated. Increase, fluctuations in physical properties and variations. On the contrary, if the moisture content of the chip is less than 800 ppm, the viscosity when melted becomes too high, and the film-forming property (easy to stretch) deteriorates. In addition, the optimal moisture content of the chip | tip supplied into a hopper is 850 ppm or more and 950 ppm or less.

(3) Maintaining temperature when resin is supplied to the hopper As described above, even when the moisture content of the chip is adjusted to 800 ppm or more and 1000 ppm or less, the chip after heating and drying is allowed to stand to reach room temperature (room temperature). When it is supplied to the hopper after being lowered, a film roll with uniform physical properties cannot be obtained. That is, in order to obtain the film roll of the present invention, it is necessary to supply the chips heated and dried by a blender or the like to the hopper while keeping the temperature high. Specifically, the chips dried by heating with a blender need to be supplied to the hopper while being maintained at 80 ° C. or higher, and more preferably supplied to the hopper while being maintained at 90 ° C. or higher. When the temperature of the chip supplied to the hopper is lower than 80 ° C., the resin bite becomes worse, causing vertical thickness unevenness, physical property fluctuations and variations, and the film roll of the present invention cannot be obtained. In addition, when drying a chip | tip with apparatuses, such as a blender, it is necessary to adjust drying temperature to 150 degrees C or less. If the drying temperature exceeds 150 ° C., hydrolysis may occur during drying, which is not preferable. In addition, when the temperature of the chip heat-dried by the blender falls below 80 ° C., it is necessary to reheat the chip to 80 ° C. or higher and supply it to the hopper.

(4) Optimizing the hopper shape By using a funnel-shaped hopper as the final hopper and making its inclination angle 70 ° or more, large chips can be easily dropped as well as small chips. Since it descends while maintaining a horizontal plane, it is effective in reducing raw material segregation. A more preferable inclination angle is 75 ° or more. The inclination angle of the hopper is an angle between the funnel-shaped hypotenuse and the horizontal line segment. A plurality of hoppers may be used upstream of the final hopper. In this case, in any hopper, the inclination angle must be 70 ° or more, and more preferably 75 ° or more.

  It is also preferable to reduce the ratio of the fine powder generated due to the cutting of the raw material chips used in order to suppress fluctuations in the boiling water shrinkage rate. Since the fine powder promotes the occurrence of raw material segregation, it is preferable to remove the fine powder generated in the process and reduce the ratio of the fine powder contained in the hopper. The ratio of the fine powder contained is preferably within 1% by weight and more preferably within 0.5% by weight throughout the entire process until the raw material chips enter the extruder. As a specific method for reducing the fine powder ratio, the fine powder is removed by passing a sieve at the time of chip formation with a strand cutter or by passing a cyclone air filter when the raw material chips are air-fed. The method of doing can be mentioned.

(5) Addition of anti-segregation agent during resin mixing Further, as a means of reducing raw material segregation in the hopper, a sublimation anti-segregation agent is added in the mixing of the polyamide resin and the elastomer in the hopper. Is also preferable. As such a sublimation segregation preventing agent, a low boiling glycol can be used, and among them, polyoxyethylene / polyoxypropylene glycol can be suitably used. The amount of the sublimation segregation inhibitor added to the polyamide resin raw material chip and the elastomer raw material chip is in the range of 0.02% to 2.00% with respect to the total weight of the polyamide resin and the elastomer. It is preferable to do this. If it is less than 0.02%, it is not preferable because a sufficient segregation preventing effect cannot be obtained. On the other hand, if it is 2.00% or more, there is a possibility that it cannot be completely sublimated.

  In addition, as a means for reducing raw material segregation in the hopper, it is also a preferable means to optimize the capacity of the hopper used. Here, the proper capacity of the hopper is in the range of 15 to 120% by weight with respect to the discharge amount per hour of the extruder, and 20 to 100% by weight with respect to the discharge amount per hour of the extruder. It is more preferable that it is within the range.

  In addition, as a method of mixing the raw material chip of polyamide resin and the raw material chip of elastomer, it is also possible to supply to the final hopper and the extruder through an intermediate hopper (buffer hopper) for mixing.

  In addition, when mixing multiple types of raw materials as polyamide-based resins and elastomers, mixing is performed while quantitatively supplying multiple types of raw materials into the hopper from a device that continuously supplies quantitative raw material chips. The method or the method of mixing in advance using a blender, paddle dryer, etc. can be mentioned, but when using the latter, the raw material chip size is set so that the raw material segregation does not occur when the mixture is discharged. It is preferable to make it small.

(6) Elimination of adverse effects due to addition of segregation inhibitor (suction when molten resin contacts metal roll)
When the chip was melt extruded to obtain an unstretched film, the chip was melted at a temperature of 200 to 300 ° C. by an extruder and extruded from a T-die to form a film (sheet) (ie, casting). Then, it cools rapidly by the method wound around cooling rolls, such as a metal roll cooled to predetermined temperature. In addition, from the viewpoint of vertical thickness variation, physical property fluctuations, and variations, a preferable melt extrusion temperature is 240 ° C. to 290 ° C. In order to obtain the film roll of the present invention, when the molten resin is wound around the metal roll, the air gap (that is, the vertical distance from the exit of the T die lip to the chill roll surface) is adjusted to 20 to 60 mm, Using a suction device such as a vacuum box (vacuum chamber) with a wide suction port, the part that contacts the surface of the molten resin and the cooling roll is sucked across the entire width of the molten resin in the direction opposite to the winding direction. By doing so, it is preferable that the molten resin is forcibly adhered to the metal roll.

  And in that case, in order to prevent the situation where the sublimation segregation preventing agent described above impedes the adhesion of the molten resin to the cooling roll, the suction air velocity at the suction port is set to 2.0 to 7.0 m / sec. Need to be adjusted to 2.5 to 5.5 m / sec. It is more preferable to adjust to. Furthermore, the vacuum box may have a series of suction ports, but the suction ports are divided into a predetermined number of sections in the lateral direction in order to facilitate adjustment of the suction air velocity at the suction ports. It is preferable that the suction air speed can be adjusted for each section. Further, when the casting speed is increased, an accompanying flow is generated with the rotation of the metal roll, and the adhesion of the molten resin to the metal roll is hindered. In order to improve the degree of adhesion of the metal roll to the metal roll, a wide shield plate made of a soft material such as Teflon (registered trademark) is installed on the upstream side adjacent to the suction device (the metal roll rotates relative to the suction device). It is preferable to install on the side opposite to the direction) to block the accompanying flow. Furthermore, in order to obtain the film roll of the present invention, it is necessary to suppress the variation in the suction wind speed of the vacuum box within ± 20% of the average suction wind speed (set value), and more preferably within ± 10%. . In addition, it is preferable to adjust the suction force by providing a filter in the vacuum box and feeding back the differential pressure before and after the filter so that the suction wind speed of the vacuum box does not fluctuate due to oligomer dust or the like.

  Moreover, in order to obtain the film roll of the present invention, when the molten resin is wound around the cooling roll, a DC negative charge of 90 to 105 mA is applied to the molten resin sheet at 2 to 15 kv from the needle electrode, It is necessary to continuously contact and quench the metal roll while glow discharge. In this case, it is preferable to adjust the DC negative charge to be applied in the range of 7 to 14 kv because vertical thickness variation, physical property fluctuations and variations are reduced. Further, in order to obtain the film roll of the present invention, it is necessary to suppress the variation of the DC negative charge to be applied within an average negative charge (set value) of ± 20%, more preferably within ± 10%. .

(7) Optimization of stretching conditions As a method of biaxially stretching an unstretched film, the unstretched film is stretched in the longitudinal direction with a roll-type stretching machine and stretched in the transverse direction with a tenter-type stretching machine, followed by heat setting treatment and relaxation. It is necessary to employ a longitudinal / lateral stretching method for performing the treatment. Furthermore, in order to obtain the film roll of the present invention, it is necessary to adopt a so-called longitudinal-longitudinal-lateral stretching method as a biaxial stretching method. The longitudinal-longitudinal-transverse stretching method means that, in longitudinal stretching of a substantially unoriented polyamide-based mixed resin film, the first-stage stretching is performed and the second-stage stretching is continued without cooling to Tg or less. After that, it is a method of transverse stretching at a magnification of 3.0 times or more, preferably 3.5 times or more, and further heat setting. And in order to obtain the film roll of this invention, when performing longitudinal-longitudinal-lateral stretching mentioned above, it is necessary to make the longitudinal stretch ratio of the 1st stage higher than the longitudinal stretch ratio of the 2nd stage. That is, by making the first stage longitudinal draw ratio higher than the second stage longitudinal draw ratio, it is possible to obtain a film roll with good physical properties such as boiling water shrinkage and few variations in those physical properties. It becomes. In addition, when performing longitudinal-longitudinal-lateral stretching, it is usually easier to make the first-stage longitudinal stretching ratio lower than the second-stage longitudinal stretching ratio without causing sticking to the roll during the first-stage stretching. However, by using a special roll such as a Teflon (registered trademark) roll, even if the longitudinal stretch ratio of the first stage is higher than the longitudinal stretch ratio of the second stage, it causes sticking to the roll. It becomes possible to stretch easily.

  When performing longitudinal-longitudinal-lateral stretching as described above, the first-stage longitudinal stretching is preferably stretched about 2.0 to 2.4 times at a temperature of 80 to 90 ° C. When the draw ratio at the first stage is out of the above range and becomes high, the thickness unevenness in the vertical direction becomes large, which is not preferable. In addition, the longitudinal stretching in the second stage is preferably stretched about 1.3 to 1.7 times at a temperature of 65 to 75 ° C. If the draw ratio of the second stage falls outside the above range, it becomes unfavorable because the boil distortion increases and becomes unpractical.On the other hand, if the draw ratio of the second stage goes out of the above range, it becomes high. The strength in the direction (such as strength at 5% elongation) becomes low and becomes unpractical.

  Moreover, when performing longitudinal-longitudinal-lateral stretching as described above, hot roll stretching, infrared radiation stretching, or the like can be employed as the longitudinal stretching method. In addition, when the polyamide-based resin film of the present invention is produced by such a longitudinal-longitudinal-lateral stretching method, not only the thickness variation in the vertical direction, the variation in physical properties and the variation are reduced, but also the variation in physical properties in the lateral direction. And variations can also be reduced. In the case of longitudinal-longitudinal-lateral stretching, the total longitudinal stretching condition is preferably 3.0 to 4.5 times.

  Moreover, when performing longitudinal-longitudinal-lateral stretching, it is preferable to stretch the lateral stretching at a temperature of 120 to 140 ° C. by about 4.0 to 5.5 times. If the transverse stretching ratio falls outside the above range, the transverse strength (5% elongation strength, etc.) becomes low and impractical, which is not preferable. Conversely, the transverse stretching ratio falls within the above range. If the deviation is high, the thermal contraction rate in the lateral direction is increased, which is not preferable. On the other hand, if the transverse stretching temperature falls outside the above range, it becomes unpreferable because the boil distortion becomes large and becomes impractical, and conversely, if the transverse stretching temperature rises outside the above range, It is not preferable because the strength (strength at 5% elongation, etc.) decreases and becomes impractical.

  Furthermore, in order to obtain the film roll of this invention, it is preferable to perform the heat setting process after longitudinal-longitudinal-lateral stretching at the temperature of 180-230 degreeC. If the temperature of the heat setting treatment falls outside the above range, the heat shrinkage rate in the longitudinal direction and the transverse direction increases, which is not preferable. On the contrary, if the temperature of the heat setting treatment rises outside the above range, biaxial stretching Since the impact strength of a film becomes low, it is not preferable.

  In addition, in order to obtain the film roll of the present invention, it is preferable to relax the relaxation treatment after heat setting by 2 to 10%. If the rate of relaxation treatment falls outside the above range, the thermal contraction rate in the longitudinal direction and the transverse direction increases, which is not preferable. Conversely, if the rate of relaxation treatment falls outside the above range, the longitudinal direction and the width direction The strength (such as strength at 5% elongation) becomes low and becomes unpractical.

  Further, the width of the film roll is not particularly limited, but from the viewpoint of easy handling, the lower limit of the width of the film roll is preferably 0.35 m or more, and more preferably 0.50 m or more. . On the other hand, the upper limit of the width of the film roll is preferably 2.5 m or less, more preferably 2.0 m or less, and further preferably 1.5 m or less. In addition, the winding length of the film roll is not particularly limited, but the lower limit of the winding length of the film roll is preferably 500 m or more and more preferably 1,000 m or more from the viewpoint of ease of winding and handling. . On the other hand, the upper limit of the roll length of the film roll is preferably 2,5000 m or less, more preferably 20,000 m or less, and further preferably 15,000 m or less. In addition, when a film thickness is about 15 micrometers, it is especially preferable in it being 12000 m or less. In addition, as the winding core, usually, paper of 3 inches (7.62 cm), 6 inches, 8 inches, etc., a plastic core or a metal core can be used.

  On the other hand, the thickness of the film constituting the polyamide-based mixed resin film roll of the present invention is not particularly limited. For example, the packaging polyamide-based film is preferably 8 to 50 μm, and more preferably 10 to 30 μm.

  In addition, the polyamide resin film constituting the film roll of the present invention includes a lubricant, an anti-blocking agent, a thermal stabilizer, an antioxidant, an antistatic agent, a light-proofing agent, and an impact resistance within a range that does not impair the properties. It is also possible to include various additives such as an improving agent. In particular, it is preferable to contain various inorganic particles for the purpose of improving the slipperiness of the biaxially stretched film. In addition, as the inorganic particles, those having an average particle size (that is, average particle size) of 0.5 to 5.0 μm are preferable, and silica particles are particularly preferable. If the average particle size is less than 0.5 μm, good slipperiness will not be obtained. Conversely, if the average particle size is more than 5.0 μm, transparency will be poor or so-called “missing” will occur during printing. This is not preferable. In addition, the measurement of the average particle diameter can employ a method of calculating the weight average diameter from the particle size distribution obtained by a Coulter counter, and can be measured from the particles before being added to the polyamide resin. It is also possible to measure from particles precipitated by dissolving a resin-based resin film with an acid. Moreover, it is preferable to add an organic lubricant such as ethylenebisstearic acid that exhibits the effect of reducing the surface energy because the slipping property of the film constituting the film roll becomes excellent.

  Furthermore, the polyamide-based resin film constituting the film roll of the present invention can be subjected to heat treatment or humidity control treatment in order to improve dimensional stability depending on the application. In addition, in order to improve the adhesion of the film surface, corona treatment, coating treatment, flame treatment, etc., and processing such as printing, vapor deposition and the like can be performed.

  It should be noted that only one of the above-mentioned means (1) to (7) does not effectively contribute to the reduction of fluctuations in the physical properties of the film roll, and the means (1) to (7) are combined. Therefore, it is considered that the change in physical properties of the film roll can be reduced very efficiently.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the embodiments of the examples, and can be appropriately changed without departing from the spirit of the present invention. . Properties of raw material chips A to H used in Examples and Comparative Examples, composition of raw material chips used in Examples and Comparative Examples, and film forming conditions of film rolls in Examples and Comparative Examples are shown in Tables 1 and 2, respectively. Show. Chip A is made of nylon 6 (relative viscosity = 2.8, Tg = 41 ° C.) 99.70% by weight and silica particles 0.30% by weight. Chips B and H are made of nylon 12 and PTMG. (Polytetramethylene glycol) and a copolymer (relative viscosity = 2.0) 99.85% by weight, ethylene bis stearic acid amide 0.15% by weight, chip C, nylon 6 and PEG ( Polyethylene glycol) (relative viscosity = 2.4) 99.85% by weight, ethylenebisstearic acid amide 0.15% by weight, chip D is an ethylene / methacrylic acid copolymer ( MFR (Melt Flow Rate) at 190 ° C. = 2.4 g / 10 minutes) 99.85% by weight, ethylenebisstearic acid amide 0.15% by weight Chip E is composed of 99.85% by weight of ethylene / butene copolymer (MFR = 2.0 g / 10 min) and 0.15% by weight of ethylenebisstearic acid amide, and chip F is made of ethylene ionomer ( MFR = 2.4 g / 10 min) and 99.85 wt% ethylene bis-stearic acid amide 0.15 wt%. Chip G is a styrene-butadiene copolymer (MFR = 2.8 g / 10 min). ) 99.85% by weight and ethylenebisstearic acid amide 0.15% by weight. In addition, the silica particles added to the chip A have an average particle size of about 3.0 μm. The shapes of the chips A to H are all elliptic cylinders, and the chips B to G have the same cross-sectional major axis, cross-sectional minor axis, and chip length.

[Example 1]
The above chip A was preliminarily dried using a 15 kl blender apparatus while being heated to about 120 ° C. for about 8.0 hours. On the other hand, the above chip B was pre-dried while being heated to about 80 ° C. for about 8.0 hours using another blender apparatus of 15 kl. When a predetermined amount of each chip was collected from the blender and the moisture content was measured, the moisture content of chips A and B was 800 ppm. The moisture content was measured using a Karl Fischer moisture meter (MKC-210 manufactured by KYOTO Electronics) under the conditions of a sample weight of 1 g and a sample heating temperature of 230 ° C.

  And the chip | tip in each blender after preliminary drying was continuously supplied separately into the mixing mixer with the fixed screw feeder. The supply amount of chip A was 97.0% by weight, and the supply amount of chip B was 3.0% by weight. In addition, ethylene bis stearic acid amide (Light Amide WE-183 manufactured by Kyoei Chemical Co., Ltd.) is used as a lubricant in the hopper to which the chips A and B are supplied. .5 (0.15 parts by weight). Furthermore, as a sublimation segregation preventing agent, polyoxyethylene / polyoxypropylene glycol (Newpol PE-64 manufactured by Sanyo Chemical Co., Ltd.) was added so as to be 1000 ppm with respect to the total weight of chip A and chip B.

  Thereafter, the mixed raw material of chip A and chip B mixed in the mixing mixer as described above was continuously supplied to the hopper directly above the extruder. The hopper had a capacity of 150 kg of raw material chips, and the discharge rate of the extruder was 450 kg per hour. The inclination angle of the hopper was adjusted to 70 °. In Example 1, the average major axis, the average minor axis, and the average chip length of the elastomer chip (Chip B) are the average major axis, average minor axis, and average of the polyamide-based resin chip (Chip A) that is most used. Each is included within a range of ± 20% of the chip length.

  Further, when the chips A and B were supplied into the hopper, they were supplied to the hopper within a short time after drying so that the temperature of the chip in each blender would not become too low. The temperatures of chips A and B immediately before being supplied to the hopper were both about 91 ° C. Then, the supplied chips A and B are sufficiently mixed in a hopper, melt-extruded from a T die at 270 ° C. by a single-screw extruder, wound around a rotating metal roll cooled to 17 ° C., and rapidly cooled. Thus, an unstretched film having a thickness of 257 μm was obtained. In addition, the take-up speed of the unstretched film (rotational speed of the metal roll) is about 60 m / min. Met.

  In addition, the air gap when the molten resin is wound around the metal roll is adjusted to 40 mm, and by applying a negative DC charge of 100 mA at 11 ± 1.1 kv from the needle electrode to the molten film, glow discharge is performed. The molten resin was electrostatically adhered to a metal roll. Further, when the molten resin is wound around the metal roll, the portion where the molten resin comes into contact with the metal roll is opposite to the direction in which the resin is wound using the vacuum box over the entire width of the molten resin. By attracting in the direction, adhesion of the molten resin to the metal roll was promoted. The suction air velocity of the vacuum box is 5.0 ± 0.5 m / sec. Over the entire width of the suction port (that is, the entire width of the molten resin). It adjusted so that it might become.

  Thereafter, the obtained unstretched film was longitudinally stretched (first longitudinal stretching) about 2.1 times at a stretching temperature of about 85 ° C. by a Teflon (registered trademark) roll, and then stretched at a stretching temperature of about 70 by a ceramic roll. Longitudinal stretching (second longitudinal stretching) was performed at about 1.5 times at a temperature. Further, the longitudinally stretched sheet is continuously led to a tenter, stretched by 4.0 times at about 130 ° C, heat-set at about 210 ° C, subjected to 5.0% lateral relaxation treatment, and then cooled. By cutting and removing both edges, a biaxially stretched film of about 15 μm was continuously formed over 2000 m to produce a mill roll. In addition, the fluctuation range of the film surface temperature when the film is continuously produced 2000 m is the average temperature ± 0.8 ° C. in the preheating step, the average temperature ± 0.6 ° C. in the stretching step, and the average temperature ± 0.5 ° C. in the heat treatment step. It was in the range. Further, the obtained mill roll was slit into a width of 400 mm and a length of 2000 m, wound up on a 3-inch paper tube, and two polyamide-based mixed resin film rolls (slit rolls) were obtained. Then, using the obtained two slit rolls (namely, those obtained from the same mill roll), the characteristics were evaluated by the following method. In the measurement of the following elastomer component content, tensile elastic modulus, pinhole property, BS (boiling water shrinkage), BSx (maximum boiling water shrinkage), BSd (boiling water shrinkage direction difference), refractive index, The first sample cut-out section is provided within 2 m from the end of film winding, and the second to twentieth sample cut-out section is provided approximately every 100 m from the first sample cut-out section, and the 21st within 2 m from the beginning of film winding. Sample cutout portions were provided, and sample films were cut out from the first to 21st sample cutout portions. The evaluation results are shown in Tables 3-9. When showing the evaluation results, for the impact strength and the laminate strength, the measured average values of the sample samples and the fluctuation range of the values of the sample samples were shown. For S-curl, the number of sample samples at each evaluation level and the overall evaluation level of all sample samples are shown.

[Content of elastomer component]
A polyamide-based mixed resin film is cut perpendicularly to the surface and perpendicular to the winding direction to produce ultrathin sections, and the specimen is prepared by staining with phosphotungstic acid and ruthenium oxide by the ultrathin piece method. did. Thereafter, an electron micrograph (thickness direction: about 160 mm × winding direction: about 220 mm) was taken with a transmission electron microscope (JEM2010) manufactured by JEOL Ltd. at a magnification of 10,000 times. And the ratio which occupies for the whole area of the elastomer part dye | stained with phosphotungstic acid and ruthenium oxide using the image processing apparatus (analySIS) by JEOL Ltd. was computed as a content rate of an elastomer component.

[Tensile modulus]
The polyamide-based mixed resin film was sampled to a length of 150 mm and a width of 15 mm, and was conditioned for 24 hours in an atmosphere of a temperature of 23 ° C. and a relative humidity of 50%. Then, under the conditions of a temperature of 23 ° C. and a relative humidity of 50%, in accordance with JIS K-7127, using an autograph AG-100E type manufactured by Shimadzu Corp. The tensile modulus was calculated as the ratio of the tensile stress within the tensile proportional limit and the corresponding strain.

[Boiling water shrinkage]
A biaxially oriented polyamide-based resin film (sample film) cut out from each cut-out portion of one slit roll was cut into a square shape with a side of 21 cm and left for 2 hours or more in an atmosphere of 23 ° C. and 65% RH. Draw a circle with a diameter of 20 cm centered on the center of the sample, draw a straight line passing through the center of the circle in the direction of 0 to 165 ° clockwise at 15 ° intervals, with the vertical direction (film drawing direction) being 0 °. The diameter in the direction was measured and taken as the length before treatment. The cut sample was then heat-treated in boiling water for 30 minutes, then removed and wiped off the moisture adhering to the surface, air-dried, and left in an atmosphere of 23 ° C. and 65% RH for 2 hours or more, as described above. The length of the straight line drawn in each diametric direction is measured and set as the length after treatment, and BS (boiling water shrinkage rate), BSx (maximum boiling water shrinkage rate), BSax (average boiling water shrinkage rate), BSd (boiling water shrinkage direction difference) and BSad (average boiling water shrinkage direction difference) were calculated.

  Then, the maximum / minimum in the maximum boiling water shrinkage (BSx) of all the samples is obtained, and the difference between the larger one of the maximum / minimum average boiling water shrinkage (BSax) and the average boiling water shrinkage And the ratio (%) of the difference to the average boiling water shrinkage (BSax) was calculated to obtain the variation rate of the maximum boiling water shrinkage (BSx) with respect to the average boiling water shrinkage (BSax). In addition, the maximum / minimum difference in boiling water shrinkage direction difference (BSd) of all samples is obtained, and the difference between the maximum / minimum average boiling water shrinkage direction difference (BSad) and the average boiling water shrinkage rate. The difference in boiling water shrinkage direction difference (BSd) with respect to the average boiling water shrinkage direction difference (BSad) is calculated by calculating the ratio (%) of the difference to the average boiling water shrinkage direction difference (BSad). The rate was determined.

[Vertical thickness unevenness]
The slit roll was slit to a width of about 3 cm over the entire length in the longitudinal direction to prepare a slit roll for thickness spot measurement. Thereafter, an average thickness, a maximum thickness, and a minimum thickness over the entire length in the longitudinal direction were determined using a thickness spot measuring device (wide range high sensitivity electronic micrometer K-313A) manufactured by Anritsu Corporation. And by calculating the difference between the average thickness and the larger one of the maximum thickness and the minimum thickness among the maximum thickness and the minimum thickness, and calculating the ratio (%) of the difference to the average thickness by the following formula 7. The variation rate of thickness over the entire length in the longitudinal direction was calculated.
Variation rate of thickness = | maximum thickness or minimum thickness−average thickness | / average thickness 7

[Refractive index]
Using an “Abbe refractometer 4T type” manufactured by Atago Co., Ltd., each sample film cut out from each sample cut-out part was left in an atmosphere of 23 ° C. and 65% RH for 2 hours or more, and then the refractive index in the thickness direction ( Nz) was measured. Also, the average average refractive index of all sample films is calculated, and as shown in Table 8, the difference between the maximum or minimum Nz and the average refractive index in all samples is calculated, and the ratio of the difference to the average refractive index is calculated. Was calculated as the rate of change.

[Impact strength]
Each sample film cut out from each cut-out part was allowed to stand in an atmosphere of 23 ° C. and 65% RH for 2 hours or more, and then a “film impact tester TSS type” manufactured by Toyo Seiki Seisakusho was used. The breaking strength was measured with a hemispherical impactor to determine the impact strength. The average impact strength of all sample films was also calculated.

[Lamination workability]
Using a slit roll (obtained from the same mill roll) different from the slit roll whose boiling water shrinkage rate, longitudinal thickness unevenness, refractive index, and impact strength were measured, the biaxially oriented polyamide constituting the slit roll After applying urethane AC agent (“EL443” manufactured by Toyo Morton Co., Ltd.) to a resin-based resin film, a 15 μm-thick LDPE (low density polyethylene) film using a single test laminator device manufactured by Modern Machinery Is extruded at 315 ° C., and a 40 μm thick LLDPE (Linear Low Density Polyethylene) film is continuously laminated thereon, and a laminate film roll having a three-layer structure composed of polyamide resin / LDPE / LLDPE is provided. Obtained. Moreover, the workability at the time of manufacturing a laminate film roll was evaluated in the following three stages.
○: No wrinkle on the roll and condition adjustment is not required. Δ: Roll wrinkle is eliminated by condition adjustment. ×: No matter how the condition is adjusted, wrinkle is generated on the roll.

[Lamination strength]
In addition, the laminate film cut out from the laminate film roll was cut out into a width of 15 mm and a length of 200 mm as a test piece, and “Tensilon UMT-II-500 type” manufactured by Toyo Baldwin Co., Ltd. was used. The peel strength between the polyamide resin film layer and the LDPE layer was measured under the condition of 65% humidity. The tensile rate was 10 cm / min, the peel angle was 180 degrees, and water was added to the peeled portion for measurement. The laminate strength is measured by cutting out the first sample piece within 2 m from the end of winding of the laminate film roll, and cutting out the second to 19th sample pieces every about 100 m from the cut out portion of the first sample piece. The 20th sample piece was cut out within 2 m from the beginning of winding of the film, and the measurement was performed on each of the first to 20th sample pieces. Moreover, the average of those measured values was also calculated.

[S-curl phenomenon]
The laminate film wound up as a laminate film roll as described above is folded into two parallel to the winding length direction using a test sealer manufactured by Seibu Machinery Co. Then, 10 mm in the vertical direction was intermittently heat-sealed at intervals of 150 mm to obtain a semi-finished product having a width of 200 mm. This was cut in the winding length direction and both edges were cut so that the seal portion was 10 mm, and then cut at the boundary of the seal portion in the direction perpendicular to this to produce a three-side seal bag (seal width: 10 mm). . From these three-sided sealing bags, a three-sided sealing bag made from a portion within 2 m from the end of winding of the laminate film roll is selected as the first sample, and about 100, 200,..., 1800, 3900 sealed bags made from 1900 m apart were selected as the 2nd to 20th samples, respectively, and were made from the portion within 2 m from the start of the laminate film roll. A 3-way sealed bag was selected as the 21st sample. And after heat-treating those 21 three-way seal bags for 30 minutes in boiling water, hold them in an atmosphere of 23 ° C. and 65% RH all day and night. A load of 1 kg was applied to the entire surface of the bag, and the bag was removed after being held for a whole day and night, and the degree of bag curl (S-curl) was evaluated as follows.
◎: No warping at all. ○: Slight warping is observed. X: Warping is clearly observed. XX: Warping is remarkable.

[Pinhole resistance]
The laminated film cut out from the laminated film roll was cut into a size of 20.3 cm (8 inches) × 27.9 cm (11 inches), and the rectangular test film (laminated film) after the cutting was cut at a temperature of 23 ° C. Conditioning was allowed to stand for 24 hours or more under the condition of 50% relative humidity. Thereafter, the rectangular test film was wound into a cylindrical shape having a length of 20.32 cm (8 inches). Then, one end of the cylindrical film is fixed to the outer periphery of a disk-shaped fixing head of a gel bow flex tester (manufactured by Rigaku Kogyo Co., Ltd., NO.901 type) (conforming to the standard of MIL-B-131C). The other end of the tester was fixed to the outer periphery of a disk-shaped movable head of a tester facing the fixed head at a distance of 17.8 cm (7 inches). Then, the movable head is rotated 440 ° while approaching the fixed head in the direction of 7.6 cm (3.5 inches) along the axis of both heads opposed in parallel, and then 6.4 cm (without rotation) 2.5-inch) A one-cycle bending test in which the movement is performed in the reverse direction and the movable head is returned to the initial position is performed continuously for 3000 cycles at a rate of 40 cycles per minute. Repeated. Thereafter, the number of pinholes generated in a portion within 17.8 cm (7 inches) × 27.9 cm (11 inches) excluding the portion fixed to the outer periphery of the fixed head and movable head of the tested film was measured (ie, The number of pinholes per 497 cm ² (77 square inches) was measured).

[Example 2]
An unstretched film obtained in the same manner as in Example 1 was longitudinally stretched (first longitudinal stretching) about 2.2 times at a stretching temperature of about 90 ° C. by a Teflon (registered trademark) roll, and then by a ceramic roll. The film was stretched longitudinally (second longitudinal stretching) about 1.5 times at a stretching temperature of about 70 ° C. Further, similarly to Example 1, the longitudinally stretched sheet was continuously led to a stenter, transversely stretched 4.0 times at about 130 ° C., and heat-set at about 210 ° C. to be 5.0% transverse After the relaxation treatment, the film was cooled and both edges were cut and removed, whereby a biaxially stretched film having a thickness of about 15 μm was continuously formed over 2000 m. In addition, the fluctuation range of the film surface temperature when the film was continuously produced was, as in Example 1, the average temperature ± 0.8 ° C. in the preheating step, the average temperature ± 0.6 ° C. in the stretching step, and the average in the heat treatment step. The temperature was within the range of ± 0.5 ° C. Thereafter, the obtained film was slit and wound in the same manner as in Example 1 to obtain a polyamide-based mixed resin film roll of Example 2. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Example 3]
The polyamide-based mixture of Example 3 was the same as Example 2 except that the mixing ratio of raw material chip A and raw material chip B was 90.0% by weight of chip A and 10.0% by weight of chip B. A resin film roll was obtained. In Example 3 as well, the average major axis, average minor axis, and average chip length of the elastomer chip (Chip B) are the same as the average major axis, average minor axis, and average chip length of the polyamide resin chip (Chip A). , Each within a range of ± 20%. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Example 4]
Example 2 except that a raw material chip C was used instead of the raw material chip B, and the mixing ratio of the raw material chip A and the raw material chip C was changed to 95.0 wt% for the chip A and 5.0 wt% for the chip C. In the same manner as described above, a polyamide-based mixed resin film roll of Example 4 was obtained. In Example 4 as well, the average major axis, average minor axis, and average chip length of the elastomer chip (Chip C) are the same as the average major axis, average minor axis, and average chip length of the polyamide resin chip (Chip A). , Each within a range of ± 20%. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Example 5]
Example 2 except that the raw material chip D was used in place of the raw material chip B, and the mixing ratio of the raw material chip A and the raw material chip D was 95.0 wt% for the chip A and 5.0 wt% for the chip D. In the same manner as described above, a polyamide-based mixed resin film roll of Example 5 was obtained. In Example 5, the average major axis, the average minor axis, and the average chip length of the elastomer chip (Chip D) are the same as the average major axis, average minor axis, and average chip length of the polyamide resin chip (Chip A). , Each within a range of ± 20%. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Example 6]
Example 2 except that a raw material chip E was used instead of the raw material chip B, and the mixing ratio of the raw material chip A and the raw material chip E was changed to 95.0 wt% for the chip A and 5.0 wt% for the chip E. In the same manner as described above, a polyamide-based mixed resin film roll of Example 6 was obtained. In Example 6, the average major axis, average minor axis, and average chip length of the elastomer chip (Chip E) are the same as the average major axis, average minor axis, and average chip length of the polyamide resin chip (Chip A). , Each within a range of ± 20%. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Example 7]
Example 2 except that the raw material chip F was used instead of the raw material chip B, and the mixing ratio of the raw material chip A and the raw material chip F was changed to 95.0 wt% for the chip A and 5.0 wt% for the chip F. In the same manner as described above, a polyamide-based mixed resin film roll of Example 7 was obtained. In Example 7 as well, the average major axis, average minor axis, and average chip length of the elastomer chip (Chip F) are the average major axis, average minor axis, and average of the polyamide-based resin chip (Chip A) that is most used. Each is included within a range of ± 20% of the chip length. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Example 8]
Example 2 except that the raw material chip G was used instead of the raw material chip B, and the mixing ratio of the raw material chip A and the raw material chip G was 95.0% by weight for chip A and 5.0% by weight for chip G. In the same manner as described above, a polyamide-based mixed resin film roll of Example 8 was obtained. In Example 8, the average major axis, the average minor axis, and the average chip length of the elastomer chip (Chip G) are the average major axis, average minor axis, and average of the polyamide-based resin chip (Chip A) that is most used. Each is included within a range of ± 20% of the chip length. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Comparative Example 1]
A polyamide-based mixed resin film roll of Comparative Example 1 was obtained in the same manner as in Example 2 except that only the raw material chip A was used as the raw material. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Comparative Example 2]
The mixing ratio (weight ratio) of the raw material chips A and B is changed to 95: 5, and the preliminary drying conditions of the raw material chips A and B are heated to about 100 ° C. for about 4.0 hours. A mixed polyamide resin film roll of Comparative Example 2 was obtained in the same manner as in Example 2 except that the method was changed. After pre-drying, a predetermined amount of each chip was collected from the blender and the moisture content was measured. As a result, the moisture content of chips A and B was 1500 ppm, and the chips A and B just before being supplied to the hopper The temperatures were all about 85 ° C. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Comparative Example 3]
The polyamide of Comparative Example 3 was prepared in the same manner as in Example 2 except that the raw material chips A and B were pre-dried and then allowed to stand for about 5 hours in each blender before being supplied to the hopper immediately above the extruder. A system mixed resin film roll was obtained. The moisture content of chips A and B immediately before being supplied to the hopper was 800 ppm, and the temperature of chips A and B immediately before being supplied to the hopper was about 30 ° C. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Comparative Example 4]
When the raw material chips A and B in the blender were supplied to the hopper directly above the extruder, the polyamide mixed resin film roll of Comparative Example 4 was prepared in the same manner as in Example 2 except that the hopper inclination angle was changed to 45 °. Obtained. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Comparative Example 5]
When supplying the raw material chips A and B to the hopper immediately above the extruder, the polyamide-based mixed resin film roll of Comparative Example 5 was used in the same manner as in Example 2 except that no segregation inhibitor was added to the hopper. Obtained. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Comparative Example 6]
A polyamide-based mixed resin film roll of Comparative Example 6 was obtained in the same manner as in Example 2 except that the mixing ratio (weight ratio) of both was changed to 95: 5 using the raw material chips A and H. . In Comparative Example 6, the average major axis and average chip length of the elastomer chip (Chip H) are within ± 20% of the average major axis and average chip length of the polyamide resin chip (Chip A), respectively. Not included. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 3-9.

[Effects of Example Film]
From Tables 3 to 9, all of the film rolls of Examples 1 to 8 have very small longitudinal thickness variation across the entire roll, small fluctuations in the elastomer content, tensile modulus, boiling water shrinkage, It can be seen that the variation in physical properties such as refractive index is small. In addition, the film rolls of Examples 1 to 8 in which the variation in the elastomer content is small and the physical properties such as the tensile elastic modulus, the boiling water shrinkage, and the refractive index are small cause the S-curl phenomenon. It can be seen that the laminate processability is good. Moreover, it can be seen that the films constituting the film rolls of Examples 1 to 8 have good impact strength (toughness and pinhole resistance) and high laminate strength. Further, the pinhole resistance is very good and the fluctuation is small, and it can be seen that the pinhole resistance is suitable for packaging foods containing a lot of water such as liquid soup.

  On the other hand, the film rolls of Comparative Examples 1 to 6 have large thickness variation in the longitudinal direction and large fluctuations in the content of the elastomer, and fluctuations in physical properties such as tensile elastic modulus, boiling water shrinkage and refractive index. It can be seen that the S-curl phenomenon is observed and the laminate processability is poor. Furthermore, it can be seen that the film rolls of Comparative Examples 1 to 6 have poor pinhole resistance and large fluctuations, and are not suitable for packaging foods containing a large amount of water such as liquid soup.

  The polyamide-based mixed resin film roll of the present invention has excellent processing characteristics as described above, has very good pinhole resistance, and its fluctuation is small, so it is suitable for food retort processing applications. Can be used.

Claims (18)

It is formed by melt-extruding a mixed resin of nylon 6 and polyamide-based elastomer or polyolefin-based elastomer and then biaxially stretching, and has a width of 0.2 m or more and 3.0 m or less and a length of 300 m or more and 30000 m or less. A film roll formed by winding a film,
The amount of polyamide-based elastomer or polyolefin-based elastomer added to nylon 6 is 3 wt% or more and 10 wt% or less,
The biaxial stretching is a stretching in the transverse direction after stretching in two stages in the longitudinal direction, and the longitudinal stretching in the first stage is stretched by 2.0 to 2.4 times at a temperature of 80 to 90 ° C. The second-stage longitudinal stretching is performed by stretching 1.3 to 1.7 times at a temperature of 65 to 75 ° C., and the first-stage longitudinal stretching ratio is set to the second-stage longitudinal stretching ratio. Higher,
A first sample cutout portion was provided within 2 m from the end of film winding, a final cutout portion was provided within 2 m from the start of film winding, and a sample cutout portion was provided every 100 m from the first sample cutout portion. A polyamide-based mixed resin film roll characterized by satisfying the following requirements (a) to (c).
(A) When the tensile modulus in the film winding direction is measured for each sample cut out from each cut-out portion, the average tensile modulus, which is the average value of the tensile modulus, is 1.30 GPa or more 2 (B) For each sample cut out from each cut-out part, the variation rate of the tensile elastic modulus of all the samples is within ± 10% of the average tensile elastic modulus. measuring the content of the thermoplastic elastomer component, when calculating the average content which is the average value of their content, of all the samples, the difference between the content and the average content of the thermoplastic elastomer component The variation rate of the largest sample is within the range of ± 2% to ± 10% with respect to the average content rate. (C) The average thickness among the maximum and minimum thicknesses in the longitudinal direction of the wound roll. Difference from Larger variation rate is in the range of from ± 2% ~ ± 10% relative to the average thickness For each sample cut out from each cut-out part, the number of pinholes in a case where 3000 cycles of bending test were continuously performed at a rate of 40 cycles per minute using a gelbo flex tester was 10 The polyamide-based mixed resin film roll according to claim 1, wherein the number is 497 cm ² or less.   For each sample cut out from each cut-out part, when measuring the maximum boiling water shrinkage, which is the maximum value of the boiling water shrinkage in all directions, the average boiling water shrinkage is the average of those maximum boiling water shrinkage 3% to 6%, and among all the samples, the variation rate of the sample having the largest difference between the maximum boiling water shrinkage and the average boiling water shrinkage is ± 2% to ± 10 with respect to the average boiling water shrinkage. The polyamide-based mixed resin film roll according to claim 1, which is in a range of%.   For each sample cut out from each cutout section, the boiling water shrinkage direction difference, which is the absolute value of the difference between the boiling water shrinkage rate in the +45 degree direction with respect to the longitudinal direction and the boiling water shrinkage ratio in the −45 degree direction with respect to the longitudinal direction, is calculated. When the average boiling water shrinkage direction difference, which is the average value of the boiling water shrinkage direction differences, is 1.5% or less, the boiling water shrinkage direction difference and the average boiling water shrinkage direction among all samples. 2. The polyamide-based mixed resin film according to claim 1, wherein a variation rate of a sample having the largest difference from the difference is within a range of ± 2% to ± 10% with respect to a difference in average boiling water shrinkage rate. roll.   When the refractive index in the thickness direction was measured for each sample cut out from each cutout portion, the average refractive index, which is the average value of those refractive indexes, was 1.500 or more and 1.520 or less, and all samples 2. The polyamide based mixed resin film roll according to claim 1, wherein a variation rate of the refractive index is within a range of ± 2% with respect to the average refractive index.   The polyamide-based mixed resin film roll according to claim 1, wherein the wound polyamide-based mixed resin film is laminated with a polyolefin-based resin film.   A polyamide-based mixed resin film obtained by biaxially stretching a non-oriented sheet-like material obtained by extruding a molten polyamide-based mixed resin from a T die, contacting a metal roll, and cooling it is wound up. The polyamide-based mixed resin film roll according to claim 1.   The polyamide-based mixed resin film roll according to claim 1, wherein the polyamide-based mixed resin film is wound up by a tenter stretching method.   The polyamide-based mixed resin film roll according to claim 1, wherein the polyamide-based mixed resin film wound up sequentially biaxially is wound. 2. The polyamide-based mixed resin film roll according to claim 1, wherein the polyamide-based mixed resin film is wound around a polyamide-based mixed resin film stretched biaxially in the vertical direction and the horizontal direction.   Longitudinal direction of the sheet-like material composed of a substantially unoriented polyamide-based mixed resin in at least two steps so that the glass transition temperature of the main component of the polyamide-based mixed resin is higher than the glass transition temperature + 20 ° C. and the magnification is 3 times or more. The polyamide-based mixed resin according to claim 1, wherein the polyamide-based mixed resin film obtained by winding a polyamide-based mixed resin film that has been stretched in the transverse direction so as to have a magnification of 3 times or more after being stretched Film roll.   The polyamide-based mixed resin film roll according to claim 1, wherein the polyamide-based mixed resin film that has been heat-set after the final stretching treatment is wound up.   The polyamide-based mixed resin film roll according to claim 1, wherein the polyamide-based mixed resin film which has been subjected to a relaxation treatment after heat setting is wound up.   At least one of a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, a light resistance agent, and an impact resistance improving agent is added to the wound polyamide-based mixed resin film. The polyamide-based mixed resin film roll according to claim 1.   2. The polyamide-based mixed resin film roll according to claim 1, wherein inorganic particles are added to the wound-up polyamide-based mixed resin film. The polyamide-based mixed resin film roll according to claim 15 , wherein the inorganic particles are silica particles having an average particle diameter of 0.5 to 5.0 μm.   2. The polyamide-based mixed resin film roll according to claim 1, wherein a higher fatty acid is added to the wound-up polyamide-based mixed resin film. A film forming process for forming a film made of nylon 6 and a chip made of polyamide elastomer or polyolefin elastomer while melting and extruding, and an unstretched film obtained in the film forming process is biaxially stretched in the longitudinal direction and the transverse direction. A production method for producing a polyamide-based mixed resin film roll according to claim 1, comprising a biaxial stretching step and a roll forming step of winding a biaxially stretched film,
The manufacturing method of the polyamide-type mixed resin film roll characterized by satisfy | filling the following requirements (1)-(5).
(1) The film forming step is to melt and extrude after mixing nylon 6 chip and polyamide elastomer chip or polyolefin elastomer chip, and the shape of each chip used has a major axis and a minor axis The shape is an elliptic cylinder having an elliptical cross section, and the polyamide elastomer chip or the polyolefin elastomer chip is within ± 20% of the average major axis, average minor axis, and average chip length of the nylon 6 chip. (2) The film forming step is performed by melt extrusion after mixing the nylon 6 chip and the polyamide-based elastomer chip or the polyolefin-based elastomer chip in the film having the average major axis, the average minor axis, and the average chip length. To be , Mixing of the nylon 6 chips and polyamide elastomer chips or polyolefin elastomer chips, performed by adding a sublimable segregation inhibitor (3) the film of step is provided with a funnel-shaped hopper as a raw material chip supply unit A step of melt extrusion using an extruder, the inclination angle of the hopper being adjusted to 65 degrees or more, and a nylon 6 chip and a polyamide-based elastomer chip or polyolefin-based before being supplied to the hopper The moisture content of the elastomer chip is adjusted to 800 ppm or more and 1000 ppm or less, and the temperature of the nylon 6 chip and the polyamide elastomer chip or the polyolefin elastomer chip before being supplied to the hopper is adjusted to 80 ° C. or more ( 4) The above two The axial stretching step includes a preheating step that is performed before the stretching in the longitudinal direction and a heat treatment step that is performed after the stretching in the longitudinal direction. The fluctuation range of the surface temperature of the film at an arbitrary point in the stretching process is adjusted within the range of the average temperature ± 1 ° C. over the entire length of the film. (5) The film forming process is melted extruded from the extruder. A roll cooling step for cooling the resin by winding the resin around a cooling roll, and in the roll cooling step, the portion that contacts the surface of the molten resin and the cooling roll extends over the entire width of the molten resin. Is sucked in the direction opposite to the winding direction.