WO2013137153A1

WO2013137153A1 - Biaxially-stretched nylon film, laminate film, laminate packaging material, and manufacturing method for biaxially-stretched nylon film

Info

Publication number: WO2013137153A1
Application number: PCT/JP2013/056526
Authority: WO
Inventors: 真男高重
Original assignee: 出光ユニテック株式会社
Priority date: 2012-03-16
Filing date: 2013-03-08
Publication date: 2013-09-19
Also published as: JP2013193271A; TW201347957A

Abstract

　This biaxially-stretched nylon film has a nylon resin as a starting material, and is characterized in that the impact strength as determined in accordance with JIS P8134 is 160 KJ/m or more.

Description

Biaxially stretched nylon film, laminate film, laminate packaging material, and method for producing biaxially stretched nylon film

The present invention particularly relates to a biaxially stretched nylon film, a laminate film, a laminate packaging material and a method for producing a biaxially stretched nylon film that can be suitably used as a packaging material for cold forming.

Biaxially stretched nylon film (hereinafter also referred to as ONy film) is excellent in strength, impact resistance, pinhole resistance, etc., and is therefore often used for applications that require heavy strength loads such as heavy weight packaging and water packaging. .
The laminate packaging material including the ONy film is used as a packaging material for cold molding that is superior in safety and flexibility in shape (drawing moldability) and can be reduced in thickness and weight compared to hot molding. (For example, Patent Document 1 and Patent Document 2). A laminate packaging material including such an ONy film can be suitably used for battery packaging or pharmaceutical use.

JP 2008-44209 A JP 2005-22336 A

On the other hand, the packaging material for cold molding is required to further improve the drawability (deep drawability) as the capacity of batteries and the like increases. However, in a laminate packaging material including a biaxially stretched nylon film as described in Patent Document 1, there is no problem in ordinary drawing, but if deep drawing is performed, pinholes may be generated.
Patent Document 2 describes a packaging material including a heat-resistant resin film having an impact strength of 30000 J / m (30 KJ / m) or more. Even with such a packaging material, there is a problem in normal drawing. Must not. However, in Patent Document 2, there is a description that when the impact strength exceeds 80,000 J / m (80 KJ / m), the resin itself becomes hard, and conversely, the moldability may be hindered. The packaging material includes a heat resistant resin film having an impact strength of 30000 J / m or more and 80000 J / m or less (30 KJ / m or more and 80 KJ / m or less). In such a packaging material, pinholes may occur when deep drawing is performed.

Therefore, an object of the present invention is to provide a biaxially stretched nylon film, a laminate film, a laminate packaging material, and a method for producing a biaxially stretched nylon film having excellent deep drawability during cold forming.

In the present invention, cold molding refers to molding performed at room temperature without heating. One means of such cold forming is to use a cold forming machine used for forming aluminum foil or the like to push the sheet material into the female mold with a male mold and press it at high speed. According to such cold forming, plastic deformation such as molding, bending, shearing and drawing can be generated without heating.

In order to solve the above-mentioned problems, the present invention provides the following biaxially stretched nylon film, laminate film, laminate packaging material, and method for producing a biaxially stretched nylon film.
That is, the biaxially stretched nylon film of the present invention is a biaxially stretched nylon film made from a nylon resin, and has an impact strength defined by JIS P8134 of 160 KJ / m or more. .
The laminate film of the present invention is formed by laminating the biaxially stretched nylon film.
The laminate packaging material of the present invention is characterized by using the laminate film.

The method for producing a biaxially stretched nylon film of the present invention is a method for producing a biaxially stretched nylon film for producing the biaxially stretched nylon film, and a raw film production process for forming a raw film from the raw material, Biaxial stretching for stretching the original film under the conditions that the stretching ratio in the MD direction and the TD direction is 2.8 times or more and the maximum strain rate in the MD direction and the TD direction is 3 s ^-1 or more, respectively. And a heat setting step of heat-setting the film after the biaxial stretching step by heat treatment.
In the method for producing a biaxially stretched nylon film of the present invention, it is preferable that the biaxial stretching process is performed biaxially by a tubular biaxial stretching method.

According to the present invention, it is possible to provide a biaxially stretched nylon film, a laminate film, a laminate packaging material, and a method for producing a biaxially stretched nylon film having excellent deep drawability during cold forming.

It is a schematic block diagram which shows an example of the apparatus which manufactures the biaxially stretched nylon film of this invention.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.
[Configuration of biaxially stretched nylon film]
The biaxially stretched nylon film (ONy film) of this embodiment is formed by biaxially stretching a raw film made of nylon resin as a raw material and heat-fixing it at a predetermined temperature.
Nylon 6, nylon 8, nylon 11, nylon 12, nylon 6,6, nylon 6,10, nylon 6,12, etc. can be used as the nylon resin as the raw material. Nylon 6 (hereinafter also referred to as Ny6) is preferably used from the viewpoint of physical properties, melting characteristics, and ease of handling.
Here, the chemical formula of Ny6 is shown in the following formula (1).

The number average molecular weight of the raw material nylon resin is preferably 15000 or more and 30000 or less, and more preferably 22000 or more and 24000 or less.

In the present embodiment, the impact strength defined in JIS P8134 must satisfy the following conditions.
The biaxially stretched nylon film needs to have an impact strength (puncture) of 160 KJ / m or more. When the impact strength is less than 160 KJ / m, the deep drawability of the film is insufficient. Further, from the viewpoint of obtaining excellent deep drawability during cold forming, the impact strength is more preferably 175 KJ / m or more. The impact strength can be measured according to the method described in JIS P8134. Furthermore, the impact strength of the biaxially stretched nylon film is preferably set to 300 KJ / m or less from the viewpoint that the effect is saturated in addition to the increase in film thickness.

Here, the tensile strength of the biaxially stretched nylon film is preferably 240 MPa or more. This is because if the tensile strength is less than 240 MPa, the deep drawability of the film may be insufficient. Further, from the viewpoint of obtaining excellent deep drawability during cold forming, the tensile strength is more preferably 250 MPa or more. The tensile strength can be measured according to the method described in ASTM D882.

Further, the elongation at break of the biaxially stretched nylon film is preferably 70% or more. This is because if the elongation at break is less than 70%, the deep drawability of the film may be insufficient. Further, from the viewpoint of obtaining excellent deep drawability during cold forming, the elongation at break is more preferably 80% or more. In particular, the breaking elongation in the TD direction is preferably 130% or less. The elongation at break can be measured according to the method described in ASTM D882.

[Composition of laminate film]
The laminate film of this embodiment is configured by laminating one or two or more other laminate base materials on at least one surface of the above-described ONy film. Specifically, other laminate base materials include, for example, an aluminum layer, a film containing an aluminum layer, a polypropylene-based or polyethylene-based seal layer (sealant layer), and the like.
In addition, the laminate packaging material of the present embodiment is made of polyethylene terephthalate (PET), polyester resin, polyvinylidene chloride resin, polyvinylidene chloride copolymer resin, lubricant, or the like on at least one surface of the above-mentioned ONy film. A laminate in which an antistatic agent or a coating layer of nitrified cotton amide resin is further laminated may be used.
By laminating such a laminate substrate, it is possible to improve manufacturing efficiency and conveyance efficiency, and functionality (chemical resistance, electrical insulation, moisture resistance, cold resistance, workability, etc.) Can be obtained.

[Composition of laminate packaging material]
The laminate packaging material of this embodiment is comprised from the said laminate film. In general, a laminate packaging material including an aluminum layer is not suitable for cold forming because the aluminum layer is easily broken by necking during cold forming. In this respect, according to the laminate packaging material of the present embodiment, the above-described ONy film has excellent drawability, so that it is possible to suppress the breakage of the aluminum layer during cold deep drawing, etc. The generation of pinholes in can be suppressed. Therefore, even when the total thickness of the packaging material is thin, a molded product having a sharp shape and high strength can be obtained.

In the laminate packaging material of the present embodiment, the total thickness of the ONy film and other laminate base material is preferably 200 μm or less. When the total thickness exceeds 200 μm, it becomes difficult to form the corner portion by cold forming, and it tends to be difficult to obtain a molded product having a sharp shape.

The thickness of the ONy film in the laminate packaging material of the present embodiment is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less. Here, if the thickness of the ONy film is less than 5 μm, the impact resistance of the laminate packaging material tends to be low, and the cold formability tends to be insufficient. On the other hand, when the thickness of the ONy film exceeds 50 μm, it is difficult to obtain an effect of further improving the impact resistance of the laminate packaging material, which is not preferable because the total thickness of the packaging material is increased.

[Production equipment for biaxially stretched nylon film]
Next, a method for producing the biaxially stretched nylon film of the present embodiment will be described based on the drawings.
First, an apparatus for producing the biaxially stretched nylon film of this embodiment will be described with an example.
As shown in FIG. 1, the film manufacturing apparatus 100 includes an original fabric manufacturing apparatus 90 for manufacturing the original fabric film 1, a biaxial stretching apparatus (tubular stretching apparatus) 10 that stretches the original fabric film 1, and stretching. A first heat treatment device 20 (preheating furnace) that preheats a base film 2 that is folded later (hereinafter also simply referred to as “film 2”), a separation device 30 that separates the preheated film 2 into two upper and lower sheets, A second heat treatment device 40 that heat-treats (heat-set) the separated film 2, a tension control device 50 that applies tension to the film 2 from the downstream side when the film 2 is heat-set, and the film 2 is heat-set. And a winding device 60 for winding the biaxially stretched nylon film 3 (hereinafter also simply referred to as “film 3”).

As shown in FIG. 1, the raw fabric manufacturing apparatus 90 includes an extruder 91, a circular die 92, a water cooling ring 93, a stabilizer plate 94, and a pinch roll 95.
The tubular stretching device 10 is a device for producing a film 2 by biaxially stretching (bubble stretching) a tubular raw film 1 with the pressure of internal air. As shown in FIG. 1, the tubular stretching device 10 includes a pinch roll 11, a heating unit 12, a guide plate 13, and a pinch roll 14.
The first heat treatment apparatus 20 is an apparatus for preliminarily heat-treating the flat film 2. As shown in FIG. 1, the first heat treatment apparatus 20 includes a tenter 21 and a heating furnace 22.
As shown in FIG. 1, the separation device 30 includes a guide roll 31, a trimming device 32, separation rolls 33A and 33B, and grooved rolls 34A to 34C. Further, the trimming device 32 has a blade 321.

The second heat treatment apparatus 40 includes a tenter 41 and a heating furnace 42 as shown in FIG.
As shown in FIG. 1, the tension controller 50 includes guide rolls 51 </ b> A and 51 </ b> B and a tension roll 52.
As shown in FIG. 1, the winding device 60 includes a guide roll 61 and a winding roll 62.

[Production method of biaxially stretched nylon film]
Next, each process which manufactures a biaxially-stretched nylon film using this film manufacturing apparatus 100 is demonstrated in detail.

(Raw film production process)
As shown in FIG. 1, the raw material nylon resin is melt-kneaded by an extruder 91 and extruded into a tube shape by a circular die 92. The tubular molten resin is cooled by a water cooling ring 93. The raw film 1 is molded by rapidly cooling a molten nylon resin as a raw material by a water cooling ring 93. The cooled original film 1 is folded by the stabilizer 94. The folded original fabric film 1 is sent to the next biaxial stretching process by a pinch roll 95 as a flat film.

(Biaxial stretching process)
As shown in FIG. 1, the original film 1 manufactured by the original film manufacturing process is introduced into the apparatus as a flat film by a pinch roll 11. The introduced raw film 1 is bubble-stretched by being heated with infrared rays at the heating unit 12. Thereafter, the film 2 after being bubble-stretched is folded by the guide plate 13. The folded film 2 is pinched by the pinch roll 14 and sent to the next first heat treatment step as a flat film 2.

At this time, the draw ratio in the MD direction and the TD direction must be 2.8 times or more, respectively. When either the MD direction or the TD direction draw ratio is less than 2.8 times, the impact strength is lowered, causing a problem in practicality.

Further, it is necessary that the maximum strain rates in the MD direction and the TD direction are 3 s ⁻¹ or more, respectively. When either of the maximum strain rates in the MD direction and the TD direction is less than 3 s ⁻¹ , the impact strength of the resulting film is lowered and the drawability is insufficient. Further, from the viewpoint of further improving the drawability, the maximum strain rate is more preferably 3.5 s ⁻¹ or more.
The strain rate refers to the rate of increase in magnification per time.
The maximum strain rate can be obtained by the following method.
First, a film sample in the middle of stretching is collected. Then, a change in the folding diameter (width) of the sample with respect to the moving distance in the moving direction of the sample is measured, and a curve indicating the relationship between the moving distance and the folding diameter (width) of the sample is created. Here, the time from the start of stretching can be calculated from the moving distance. Moreover, the relationship between the folding diameter of the sample, the folding diameter (width) of the raw film (unstretched film), and the stretching ratio in the TD direction is expressed by the following formula:
(Folded diameter of sample (width)) / (Folded diameter of raw film (width)) = (Stretch ratio in TD direction)
Therefore, by dividing the folding diameter (width) of the sample by the folding diameter (width) of the original film, the stretching ratio in the TD direction can be calculated. Therefore, a curve indicating the relationship between the time from the start of stretching and the stretching ratio in the TD direction can be created from a curve indicating the relationship between the moving distance and the folding diameter of the sample.
Next, for the sample described above, a change in the thickness of the sample with respect to the moving distance in the moving direction of the sample is measured, and a curve indicating the relationship between the moving distance and the thickness of the sample is created. Here, the time from the start of stretching can be calculated from the moving distance. Moreover, the relationship between the thickness of the sample, the thickness of the raw film, and the overall draw ratio of MD × TD is expressed by the following formula:
(Thickness of original film) / (Thickness of sample) = (Total draw ratio of MD × TD)
Therefore, the total draw ratio of MD × TD can be calculated by dividing the thickness of the sample from the thickness of the raw film. Moreover, the relationship between the MD × TD total draw ratio, the TD direction draw ratio, and the MD direction draw ratio is given by the following formula:
(MD × TD total draw ratio) / (TD direction draw ratio) = (MD direction draw ratio)
Therefore, by dividing the TD-direction stretch ratio calculated from the MD × TD total stretch ratio, the MD-direction stretch ratio can be calculated. Therefore, a curve indicating the relationship between the time from the start of stretching and the stretching ratio in the MD direction can be created from the curve indicating the relationship between the moving distance and the thickness of the sample.
With the two curves that can be created as described above, the change state of the draw ratio in the MD direction and the TD direction with respect to the time from the start of drawing can be quantified. In these curves, the maximum strain rate in the MD direction and the TD direction can be obtained by obtaining the slope of the portion where the slope of the curve is maximum.

Furthermore, it is preferable that the stretching ratio in the TD direction is larger than the stretching ratio in the MD direction at the end of stretching. Further, the difference (TD−MD) obtained by subtracting the draw ratio in the MD direction from the draw ratio in the TD direction is preferably 0.1 to 0.8 times, and more preferably 0.2 to 0.8 times. It is more preferable that it is 0.3 times or more and 0.8 times or less. If the value of TD-MD is less than the lower limit, the deep drawability of the resulting film tends to be insufficient, and the thickness accuracy of the film tends to decrease. In particular, when the value of TD-MD is 0.1 times or less, the stretching stability is inferior and the thickness accuracy of the film tends to be lowered. On the other hand, if the value of TD-MD exceeds the above upper limit, the deep drawability of the resulting film tends to be insufficient, and the stretching stability is lowered.

(First heat treatment process)
The film 2 sent from the biaxial stretching step is at or above the shrinkage start temperature of the film 2 and about 30 ° C. higher than the melting point of the film 2 while being gripped at both ends by clips (not shown) of the tenter 21. The film 2 is preheated at a low temperature or lower and sent to the next separation step.
The heat treatment temperature in the first heat treatment is preferably 120 ° C. or higher and 190 ° C. or lower, and the relaxation rate is preferably 15% or lower.
By this first heat treatment step, the crystallinity of the film 2 is increased, and the slipping property between the overlapping films is improved.

(Separation process)
As shown in FIG. 1, the flat film 2 sent through the guide roll 31 is cut into both ends by a blade 321 of a trimming device 32 and separated into two

films

2A and 2B. And

film

2A, 2B is isolate | separated, interposing air between

film

2A, 2B by a pair of

separation roll

33A, 33B located up and down apart. The incision of the flat film 2 may be performed so that a part of the ear is generated by positioning the blade 321 slightly inward from both ends, or by positioning the blade 321 in the fold portion of the film 2. , It may be performed so that the ear does not occur.
These

films

2A and 2B are overlapped again by three grooved rolls 34A to 34C positioned in order in the film flow direction, and sent to the next second heat treatment step. In addition, these grooved rolls 34A to 34C are obtained by plating the surface after the grooved processing. A good contact state between the

films

2A and 2B and the air can be obtained through the grooves.

(Second heat treatment process (heat setting process))
The overlapped

films

2A and 2B are heat-treated at a temperature equal to or lower than the melting point of the resin constituting the film 2 and about 30 ° C. lower than the melting point while being gripped at both ends by clips (not shown) of the tenter 41. It is (heat-set) and becomes a biaxially stretched nylon film 3 (hereinafter also referred to as film 3) having stable physical properties, and is sent to the next winding step.
The heat treatment temperature in the second heat treatment (heat setting) is preferably 190 ° C. or higher and 215 ° C. or lower. When the heat treatment temperature is less than the lower limit, the film shrinkage rate is increased, and the risk of delamination is increased.On the other hand, when the upper limit is exceeded, the bowing phenomenon at the time of heat setting increases, and the distortion of the film increases. The density becomes too high, the crystallinity becomes too high, and the film is difficult to deform.
In addition, the relaxation rate at this time is preferably 15% or less.
A strong tension is applied to the

films

2A and 2B in the heating furnace 42 by the tension control device 50 located on the downstream side.

(Winding process)
The film 3 heat-set in the second heat treatment step is wound as

films

3A and 3B on the two winding rolls 62 via the guide roll 61 via the tension control device 50.

[Modification of Embodiment]
The aspect described above shows one aspect of the present invention, and the present invention is not limited to the above-described embodiment, and has the configuration of the present invention and can achieve the object and effect. It goes without saying that modifications and improvements within the scope are included in the content of the present invention. In addition, the specific structure and shape in carrying out the present invention may be used as other structures and shapes within the scope of achieving the object and effect of the present invention.

For example, in this embodiment, the tubular method is adopted as the biaxial stretching method, but a tenter method may be used. Furthermore, the stretching method may be simultaneous biaxial stretching or sequential biaxial stretching.

EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples. The characteristics in each example (impact strength of the biaxially stretched nylon film and deep drawability of the laminate film) were evaluated by the following methods.
(I) Impact strength Based on the method described in JIS P8134, the impact strength of the biaxially stretched nylon film was measured using a puncture tester.
(Ii) Deep-drawing moldability The laminate film was cut to prepare a 120 × 80 mm strip piece as a sample. Using a 33 x 55 mm rectangular mold, press it with a surface pressure of 0.1 MPa, change the molding depth from 0.5 mm to 0.5 mm, and cold mold each 10 samples. (One-stage pull-in molding). The molding depth at which no pinhole was generated in any of the 10 samples in the aluminum foil was taken as the limit molding depth, and the molding depth was shown as an evaluation value. In addition, confirmation of the pinhole confirmed the transmitted light visually.
A: The limit molding depth is 5 mm or more.
B: The limit molding depth is less than 5 mm.

[Example 1]
(Raw film production process)
As shown in FIG. 1, after Ny6 pellets were melt-kneaded at 275 ° C. in an extruder 91, the melt was extruded as a tube-like film from a circular die 92, and then rapidly cooled with water (15 ° C.). Film 1 was produced.
What was used as Ny6 is Ube Industries, Ltd. nylon 6 [UBE nylon 1022FD (trade name), relative viscosity ηr = 3.5].
(Biaxial stretching process)
Next, as shown in FIG. 1, the raw film 1 is inserted between a pair of pinch rolls 11, and then heated by the heating unit 12 while a gas is being pressed into the film 1, and blown to the stretching start point to form bubbles. The biaxial stretching in the MD direction and the TD direction was performed by the tubular method by expanding and taking up with a pair of downstream pinch rolls 14. The magnification during this stretching was 3.0 times in the MD direction and 3.3 times in the TD direction. The maximum strain rate during the stretching was ^{5.0 s} -1, 4.0 s ^-1 at TD direction MD direction.
(First heat treatment step and second heat treatment step)
Next, as shown in FIG. 1, the film 2 is subjected to heat treatment at a temperature of 170 ° C. by the first heat treatment device 20, and then passed through the separation device 30 and then heat treated at a temperature of 205 ° C. by the second heat treatment device 40. And heat fixed.
(Winding process)
Next, as shown in FIG. 1, the film 3 heat-set in the second heat treatment step is wound as two films 3 </ b> A and 3 </ b> B on two winding rolls 62 via a guide roll 61 via a tension control device 50. A biaxially stretched nylon film was produced. The thickness of the obtained biaxially stretched nylon film was 15 μm.
The impact strength of the obtained biaxially stretched nylon film was measured. The obtained results are shown in Table 1.
(Production of laminate film)
The obtained biaxially stretched nylon film was used as a front substrate film, an aluminum foil having a thickness of 40 μm was used as an intermediate substrate, and a CPP film having a thickness of 60 μm was used as a sealant film to obtain a laminate film. The laminated film after dry lamination was aged at 40 ° C. for 3 days.
The deep drawability of the obtained laminate film was evaluated. The obtained results are shown in Table 1.

[Examples 2 to 5, Comparative Examples 1 to 8]
A biaxially stretched nylon film and a laminate film were produced in the same manner as in Example 1 except that each condition was changed according to the production method and production conditions (biaxial stretching method, maximum strain rate, and thickness) shown in Table 1.
The impact strength of the obtained biaxially stretched nylon film was measured. The obtained results are shown in Table 1. Further, the deep drawability of the obtained laminate film was evaluated. The obtained results are shown in Table 1.

As is clear from the results shown in Table 1, when the impact strength of the biaxially stretched nylon film satisfies the above conditions (Examples 1 to 5), it has good deep drawability during cold forming. confirmed. Moreover, it was confirmed that these biaxially stretched nylon films have good stretching stability and excellent film thickness accuracy.
On the other hand, when the impact strength of the biaxially stretched nylon film did not satisfy the above conditions (Comparative Examples 1 to 8), it was confirmed that good deep drawability was insufficient during cold forming. In particular, even in Comparative Examples 7 and 8 described as the preferred range in Patent Document 2 described above, it was confirmed that good deep drawability was insufficient during cold forming.

The biaxially stretched nylon film of the present invention is, for example, for industrial fields (such as lithium battery packaging materials mounted on electric vehicles, tablet terminal devices, smartphones, etc.), pharmaceutical fields (such as PTP packaging materials), and household goods. It can be suitably used as a packaging material that particularly requires pinhole resistance, such as packaging materials in the field (such as refill packaging for liquid detergents) and foods. The laminate packaging material of the present invention can be suitably used as a packaging material for cold molding that requires particularly excellent deep drawability.

3, 3A, 3B ... Biaxially stretched nylon film

Claims

A biaxially stretched nylon film made from nylon resin,
The biaxially stretched nylon film characterized by having an impact strength defined by JIS P8134 of 160 KJ / m or more.
A laminate film obtained by laminating the biaxially stretched nylon film according to claim 1.
A laminate packaging material using the laminate film according to claim 2.
A biaxially stretched nylon film manufacturing method for manufacturing the biaxially stretched nylon film according to claim 1,
A raw film manufacturing process for forming a raw film from the raw material,
Biaxial stretching for stretching the original film under the conditions that the stretching ratio in the MD direction and the TD direction is 2.8 times or more and the maximum strain rate in the MD direction and the TD direction is 3 s -1 or more, respectively. Process,
And a heat setting step of heat-setting the film after the biaxial stretching step by performing a heat treatment. A method for producing a biaxially stretched nylon film.
In the manufacturing method of the biaxially stretched nylon film of Claim 4,
In the biaxial stretching step, biaxial stretching is performed by a tubular biaxial stretching method. A method for producing a biaxially stretched nylon film.