JPH05192997A - Manufacture of biaxially oriented ny 6/mxd 6 blend film - Google Patents

Abstract

PURPOSE:To provide a manufacture of biaxially oriented Ny 6/MXD 6 blend film by which excellent forming stability at the time of biaxial orientation can obtained. CONSTITUTION:When the maximum orientation stress in the moving direction (MD) of a film 11 is made sigmaMD and the maximum orientation stress in the width direction (TD) of the film is made sigmaTD, sigmaMD and sigmaTD are set to be 400kg/ cm<2=sigmaTD and sigmaTD<=1600kg/cm<2> respectively. However, it is expressed by the formula of sigmaMD=(FXBMD)/A, F=T/r. Herein, the reference F shows orienting forces, BMD is orientation magnification in the MD direction, A is the cross-sectional area of a raw material film, T is the rotational torque of nip rollers 12, 17, and (r) is the radius of the nip rollers. Also, it is expressed by the formula of sigmaTD=(DELTAPXR)/t. Herein, the reference DELTAP denotes the inner pressure of a bubble 16, R is the radius of the bubble, and (t) is the thickness of the film 11.

Description

Detailed Description of the Invention

[0001]

The present invention relates to biaxially stretched Ny6, MX.
The method for producing a D6 blend film can be used in the food packaging field, industrial material field and the like.

[0002]

BACKGROUND ART Nylon-based films such as nylon 6 and nylon 66 produced by simultaneously biaxially stretching by a tubular method are excellent in mechanical and optical characteristics such as strength and transparency. Have Conventionally, in order to impart a gas barrier property to such a biaxially stretched film, a PVDC (polyvinylidene chloride) emulsion is generally applied to the film surface, so-called K coating.

[0003]

K-coated nylon films (KONy) generate harmful hydrogen chloride gas and chlorine gas when they are incinerated, and therefore, like PVC, they are feared to have an adverse effect on the environment. In addition, since the K-coated product is a PVDC emulsion, it is weak against hot water and is retorted (about 110 to 135 ° C).
There was a restriction that it could not be used for business. Moreover,
When the PVDC emulsion is applied, the inorganic substances are likely to aggregate to cause color loss, which causes a problem in halftone printability that expresses a delicate color tone, making it difficult to perform high-grade printing.

On the other hand, Ny6 (nylon 6) and MXD6
The film blended with (meta-xylylene adipamide) can solve these drawbacks, but the bubbles are not stable during biaxial stretching by the tubular method, so the bubbles may roll or sometimes There was a manufacturing problem that the bag was broken. Incidentally, conventionally, in order to solve such a problem, a production method based on control of a draw ratio, a draw temperature, a draw speed, etc. has also been proposed, but conditions for obtaining good molding stability are not always specified exactly. It wasn't possible. Therefore, the present invention provides Ny6 and MXD.
An object of the present invention is to provide a production method capable of improving the molding stability of a 6-blend film during biaxial stretching.

[0005]

The inventor of the present invention has
Ny6 (nylon, biaxially stretched by the tuber method
6), MXD6 (meta-xylylene adipamide) blend
In the method for producing a base film, various types of films involved in stretching are
As a result of confirming the parameters by experiments, the movement of the film
Direction (MD) maximum stretching stress σ_MDAnd the width direction of the film
(TD) maximum stretching stress σ _TDFocusing on these σ_MDWhen
σ_TDBy setting the manufacturing conditions based on
It was found that the fruit was obtained.

That is, the present invention is characterized in that the conditions σ _MD and σ _TD are set as follows. 400 kg / cm ² ≦ σ _TD ≦ 1600 kg / cm ² 400 kg / cm ² ≦ σ _MD ≦ 1600 kg / cm ² However, the above σ _MD and σ _TD are respectively represented by the following formulas. σ _MD = (F × B _MD ) / A F = T / r

Here, F is the stretching force (kg), B _MD is the stretching ratio in the MD direction, A is the cross-sectional area (cm ² ) of the original film, and T is
Is the rotation torque (kg · cm) of the nip roll, and r is the radius (cm) of the nip roll. σ _TD = (ΔP × R) / t where ΔP is the bubble internal pressure (kg / cm ² ), R is the bubble radius (cm), and t is the film thickness (cm). The N
The chemical formula of y6 is shown in Chemical Formula 1 below, and the chemical formula of MXD6 is shown in Chemical Formula 2 below.

[0008]

[Chemical 1]

[0009]

[Chemical 2]

When σ _MD and σ _TD exceed 1600 kg / cm ² , continuous production cannot be performed because bubbles are frequently broken during stretching. On the other hand, when σ _MD and σ _TD are less than 400 kg / cm ² , bubbles in the process of stretching become unstable, resulting in poor film thickness accuracy. Both σ _MD and σ _TD preferably have an upper limit of 1500 kg / cm ² and a lower limit of 600 kg / c.
m ²

Biaxially stretched Ny6, MX according to the present invention
Necessary additives can be appropriately added to the D6 blend film. Examples of such additives include anti-blocking agents (inorganic fillers and the like), water repellents (ethylene bisstearate and the like), and lubricants (calcium stearate and the like).

[0012]

Example 1 A raw material blended with an extruder at a ratio of 60 wt% Ny6 and 40 wt% MXD6 was extruded at 270 ° C. to form a tubular film, which was then cooled with a water-cooled ring at a temperature of 15 ° C. Then, it was rapidly cooled to prepare a raw film having a diameter of 90 mm and a thickness of 130 μm. Ny6 used here is UBE nylon 1023 FD [trade name, relative viscosity η _r = 3.7, manufactured by Ube Industries, Ltd.], and MXD6 is MX nylon 6007.
[Product name, relative viscosity η _r = 2.7, Mitsubishi Gas Chemical Co., Inc.
Made].

Next, as shown in FIG. 1, after the raw film 11 is fed between a pair of nip rolls 12, it is heated by a heater 13 at 310 ° C. while a gas is being injected into the nip rolls 12, and a stretching start point is set. Air volume of 15m ³ / min from air ring 14
By blowing 15 onto the bubble 16 to expand it and taking it up with a pair of downstream nip rolls 17, simultaneous biaxial stretching was carried out to obtain a biaxially stretched Ny6 and MXD6 blend film 18. This draw ratio is in the moving direction (MD) of the film.
It was 3.0 times and 3.2 times in the width direction (TD) of the film.

During this simultaneous biaxial stretching, the pressure inside the bubble 16, the radius of the bubble 16, the number of revolutions of the nip rolls 12 and 17, the load of the drive motor, the rotational torque, etc. are set to specific values,
Maximum stretching stress σ in the moving direction (MD) of the obtained film
The maximum stretching stress σ _TD in the _MD and the width direction (TD) of the film was adjusted. In this embodiment, the maximum stretching stress σ _{MD in} the MD direction of the film is 960 kg / cm ² , and the TD of the film is
The maximum stretching stress σ _{TD in the} direction was 1170 kg / cm ² .

Incidentally, these σ _MD and σ _TD are calculated by the following equation. σ _MD = (F × B _MD ) / A F = T / r where F is a stretching force of 118 kg, B _MD is a stretching ratio in the MD direction of 3.0, and A is a cross-sectional area of the raw film of 0.37 cm ² , T is the rotating torque of 592 kg · cm, r is the radius of the nip roll, 5
cm. This stretching force F is a value obtained by reading the load of the motor required to drive the nip rolls and calculating the rotational torque T from this. σ _TD = (ΔP × R) / t

Here, ΔP is the pressure inside the bubble, which is 1097 × 10 ^-4
kg / cm ² , R is a bubble radius of 14.4 cm, and t is a film thickness of 13.5 × 10 ^-4 cm. The bubble pressure ΔP is a value measured using a digital manometer. Also,
The thickness t of the film is a value calculated from the thickness of the original film / (MD stretching ratio × TD stretching ratio). In the production of the biaxially stretched Ny6, MXD6 blend film according to this example in which σ _MD and σ _TD are set as described above,
During continuous production for 24 hours, the bubbles during stretching deformation
No. 16 had no rolling and the molding stability was very good.

Examples 2 to 8 In the same manner as in Example 1 above, biaxially stretched Ny6, MXD6 blend film 18 according to Examples 2 to 8 was manufactured. However, with respect to the blend ratio of Ny6 and MXD6, the MD stretching ratio and the TD stretching ratio, the air volume of the air ring 14, and the temperature of the heater 13, the conditions were changed as shown in Table 1 below.

Further, in the simultaneous biaxial stretching, for each example,
The maximum stretching stress σ _{MD in} the MD direction of the film and the maximum stretching stress σ _{TD in the} TD direction are 400 kg / cm ² or more and 1600, respectively.
The pressure in the bubble 16 so that the pressure is within kg / cm ²
The radius of 16, the rotation speed of nip rolls 12 and 17, the load of the drive motor, and the rotation torque were set to specific values. σ _MD and σ
_In the production of the biaxially stretched film 18 according to each example in which _TD is set to an appropriate value, continuous production for 24 hours was performed, and the molding stability of the bubble 16 during stretch deformation was observed, and the results are shown below. Tables 1 and 2 are collectively shown.

[0019] In analogy to the Comparative Examples 1 to 5 above Example, was produced biaxially oriented Ny6, MXD6 blend based film according to a comparative example 1-5.
However, regarding the blending ratio of Ny6 and MXD6, the MD stretching ratio and the TD stretching ratio, the air volume of the air ring 14, and the temperature of the heater 13, the conditions were made different as shown in Tables 1 and 2 below. In the simultaneous biaxial stretching, the film σ _MD and σ _TD
The pressure inside the bubble 16, the radius of the bubble 16 and the like were set to specific values so that at least one of them fell outside the range according to the embodiment.

In the production of the biaxially stretched film according to each comparative example in which σ _MD and σ _TD were set to appropriate values, continuous production was carried out for 24 hours, and the molding stability of bubbles during stretching deformation was observed. The evaluation results are also shown in Tables 1 and 2 below. In the table below, ◎ in the molding stability column indicates that the bubble diameter variation is ± 1%, and bubble breakage and instability phenomena (up / down movement, roll, etc.) do not occur, and ○ indicates the bubble diameter. Fluctuation of ± 3%, bubble breakage and instability do not occur, ×
Indicates that the continuous molding is difficult because the bubble is broken or an unstable phenomenon occurs.

[0021]

[Table 1]

[0022]

[Table 2]

[0023] From the above Tables 1 and 2, according to embodiments 1 to 8, Ny6, maximum draw stress in the MD direction of the MXD6 blends based film sigma _MD and TD directions of the maximum draw stress sigma _TD is,
Since all of them are in the range of 400 to 1600 kg / cm ² , it can be seen that good molding stability of the bubbles 16 at the time of stretching deformation can be obtained. Further, according to Examples 1, 2, 6 and 7 in which σ _MD and σ _TD are set within the range of 600 to 1500 kg / cm ² , the molding stability becomes better. On the other hand, Comparative Examples 1 and 3
Σ _MD and σ _TD are both less than 400 kg / cm ² , while Comparative Examples 2, 4 and 5 show that at least one of σ _MD and σ _TD exceeds 1600 kg / cm ^2. It can be seen that the molding stability is poor.

[0024]

According to the manufacturing method of the present invention, Ny
6. Since good molding stability can be obtained during biaxial stretching of the MXD6 blend film, continuous production can be carried out without any trouble.

[Brief description of drawings]

FIG. 1 is a schematic view of a biaxial stretching device used in an example of the present invention.

[Explanation of symbols]

 11 Original film 13 Heater 14 Air ring 16 Bubble 18 Biaxially stretched film.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B29L 7:00 4F C08L 77:00 77:10 9286-4J

Claims (1)

[Claims] 1. Biaxially stretched Ny6 by a tubular method,
In the method for producing the MXD6 blend film, the maximum stretching stress in the moving direction (MD) of the film is σ _MD , and the maximum stretching stress in the width direction of the film (TD) is σ _TD.
And σ _MD and σ _TD are respectively set to 400 kg / cm ² ≦ σ _TD ≦ 1600 kg / cm ² 400 kg / cm ² ≦ σ _MD ≦ 1600 kg / cm ² , biaxial stretching Ny6, MXD6
Method for producing blend film. However, the above σ _MD and σ _TD
Are respectively expressed by the following equations. σ _MD = (F × B _MD ) / A F = T / r where F is the stretching force (kg), B _MD is the stretching ratio in the MD direction, A is the cross-sectional area of the original film (cm ² ), T Is the rotation torque (kg · cm) of the nip roll, and r is the radius (cm) of the nip roll. σ _TD = (ΔP × R) / t where ΔP is the bubble internal pressure (kg / cm ² ), R is the bubble radius (cm), and t is the film thickness (cm).