TWI492977B - Nylon film for pouch - Google Patents

Description

Nylon film for bags

The present invention relates to a film which has good slipperiness due to a low coefficient of friction and good processability during post-treatment, and has a good bag depth ability due to a low modulus when a bag type is produced (pocket depth) Forming characteristics).

In particular, the present invention relates to a film having a low coefficient of friction and a low modulus, which is prepared by mixing inorganic and organic particles having different types and sizes to prepare a masterbatch, and is manufactured by using a tubular film during film production. The device puts the masterbatch; and the present invention relates to a nylon film which has good processability in preparing a sealing material and improving bag depth.

Compared with other films, nylon films have high gas barrier properties and are therefore mainly used for vacuum packaging raw materials, balloons and the like, and have recently been used in chemical packaging material bags and secondary battery packaging bags.

Meanwhile, when a nylon film is manufactured, a small amount of an additive is added to prevent clogging and bending wrinkles during the stretching process or the heat treatment. Depending on the type, each film has more or less different characteristics, but they need to have high speed productivity and tearing properties, and can be easily handled by printing, lamination, etc., and their respective physical properties during post-processing.

If the films are not easy to produce and post-treat, they are difficult to use commercially, although they have good properties, and therefore, proper post-treatment and film slipperiness are important.

In other words, much of the moisture is absorbed on the surface of the nylon film with increased moisture absorption of the nylon surface, i.e., increases the coefficient of friction of the nylon film, and thus causes its slipperiness to decrease. This phenomenon deteriorates the mobility and operability during slitting, printing, laminating film, and the like during post-processing. As the defects increase, the operability is remarkably deteriorated and the yield is lowered, thus increasing the manufacturing cost, and therefore, it is required to improve the slipperiness of the film.

In order to improve the slipperiness of the film, fine unevenness may be formed on the surface of the film to reduce the contact area with the film, or the film surface may be unevenly formed by having a good material.

As a result of forming fine unevenness on the surface of the film to reduce the contact area and thus lowering the coefficient of friction, as an example of a method for improving film slip, there are the following methods: a method of slowly cooling a film by extrusion, by crystal A method of forming a ball on the surface of a film by a method of growing a ball (Japanese Patent Publication No. Sho 51-7708); a method of forming unevenness on a surface of a film by growth of a crystal ball due to addition of a crystal nucleating agent (Japanese Patent Publication No. Sho 52-41925); a method of directly coating a surface of a film with ceria or fine talc powder (Japanese Patent Publication No. Sho 48-33991); a method of polymerizing a polymer and producing a film, A method of obtaining a film by performing addition of inorganic fine particles, and the like. In addition to this, there are well-known methods such as an embossing process, a matting process, and the like.

Further, in order to improve the slipperiness of the film, by using a material having a good activity to non-homogenize the surface of the film, it is known to mix another material having good activity, such as wax or bisamide, in the raw material. ), fluorocarbon resin, etc., are used to form a film or directly coated on the surface of the film.

However, the above method may improve the slipperiness, but there are many problems in the manufacturing process or quality consistency. Since the conditions for manufacturing the film are limited, the slow cooling when the film is produced by extrusion significantly reduces the operability. The method of coating fine powder on the surface of the film deteriorates the working environment and has difficulty in controlling the amount of coating and treating foreign particles. In addition, embossing, matting, chemical processing, and the like require complicated processes, which result in an increase in cost and deterioration of physical properties of the film such as transparency and surface gloss. In addition, the method of mixing a wax or a fluorocarbon resin in a raw material causes a problem of adhesion in printing or lamination during post-treatment.

Further, the method of adding inorganic fine particles during polymerization has a preferable advantage, such as lowering the production cost, but the inorganic particles are extracted during the polymerization even during the extraction treatment, and are used for high-temperature and long-time high alkaline conditions. Processes that promote dispersibility can cause particles to become cracked or melted.

Films, basically, require high bond strength in most post-treatments such as printing, lamination, deposition, and the like. The bond strength essentially depends on the chemical structure of the base film surface, but most of the same chemical composition depends on the physical shape of the surface.

In fact, if the amount of slip agent is large, the coefficient of friction will be easily reduced, even if the slip agent is slightly increased. However, the bond strength has been largely determined by the chemical composition and can therefore be ignored. As far as it is concerned, the composition, size, shape and other factors of the slip agent have an effect on its slipperiness, but in fact, the effect of the slip agent on the surface adhesive strength during the post-treatment is negligible.

However, the use of microparticles in the slip agent to improve the surface protrusions results in an increased contact area with the surface, thereby improving the bond strength, such as the strength of the adhesive in the printing or lamination and the adhesion in the deposition during post-treatment.

In particular, nylon film as a chemical packaging bag or a secondary battery packaging bag requires high slipperiness, low modulus, and softness as described above, and in addition, bag depth characteristics are particularly important.

SUMMARY OF THE INVENTION An object of the present invention is to provide a nylon film which exhibits improved slip property due to a low coefficient of friction and exhibits excellent post-treatment workability due to its soft film characteristics.

In one aspect, according to the present invention, the nylon film includes a plurality of inorganic particles (A) and a plurality of organic particles (B), each of the inorganic particles (A) and the organic particles (B) having an average particle size of 1 Up to 5 μm, and a plurality of inorganic fine particles (C) having an average particle size of 0.05 to 2 μm, wherein the nylon film has a total content of inorganic fine particles in the range of 1600 to 13000 ppm, and a coefficient of friction of 0.05 to 0.3 according to ASTM D1894, according to ASTM D882, the modulus range is from 250 to 350 kg/cm ² , and the film haze is from 10 to 50 according to ASTM D1003.

According to the nylon film of the present invention, nylon having a relative viscosity coefficient of 2.6 to 3.5 is used as the base resin, and by combining inorganic fine particles (A) each having an average particle size of 1 to 5 μm and having a shape close to a sphere The organic fine particles (B) and the inorganic fine particles (C) having an average particle size of 0.05 to 2 μm and having an irregular block shape are used to prepare a particulate master batch. The fine particle masterbatch is extruded by using a circular die and biaxially stretching in a tubular manner, thereby producing a nylon film.

The inventors have found that mixing and using the above three kinds of microparticles will give unexpected effects, such as improved post-processing workability due to a significant decrease in the coefficient of friction in coating and printing and an increase in the bonding strength, which promotes the present invention. carry out.

Here, the fine particle master batch can be prepared by separately or wholly injecting the inorganic fine particles (A), the organic fine particles (B), and the inorganic fine particles (C). The inorganic fine particles (A) and the inorganic fine particles (C) are selected from the group consisting of phthalates, alumina, cerium oxide and kaolin, and the organic fine particles (B) may be acrylic, styrene or fluorenone polymer fine particles. More specifically, a natural or synthetic zeolite composed of aluminosilicate, alumina, cerium oxide or the like can be used as the inorganic fine particles (A). The organic fine particles (B) are synthetic bead type, and poly(meth)acrylic acid or polystyrene, organic anthracene or the like can be used. As the inorganic fine particles (C), kaolin, cerium oxide or the like can be applied.

In the process for producing a nylon film, the prepared masterbatch particles are added to produce 100 to 1000 ppm of inorganic fine particles (A), 1000 to 10,000 ppm of organic fine particles (B), and 500 to 2000 ppm of inorganic fine particles ( Film of C). The process for making a film can be carried out in a tube type which is of the simultaneous biaxial stretching type. The film formed has a machine direction (MD) modulus of 250 to 400 kg/mm ² .

The invention will be described in detail below.

The present invention aims to obtain a nylon film by adding masterbatch particles containing inorganic fine particles to improve the slipperiness of the nylon film. Here, the three inorganic fine particles each have different shapes and different sizes as the inorganic fine particles.

First, each of the inorganic fine particles (A) and the organic fine particles (B) has an average size of 1 to 5 μm and is spherical. Further, since they have an unsmooth property on the surface of the film, they also exhibit a good effect in improving the slipperiness. However, if the amount of addition is increased, the formed film has an increased haze. For the inorganic fine particles (A) and the organic fine particles (B) having a shape close to a spherical shape, since the inorganic fine particles (A) and the organic fine particles (B) have a small surface area, the affinity between the particles becomes relatively weak. This results in voids in the interface between the particles, and the polymer is stretched in the case of a sheet having an amorphous form, and then these voids increase the haze. For the inorganic fine particles (A) and the organic fine particles (B) having these characteristics, if they are small in size, they are expensive, and if they are large in size, the haze of the film is increased. Therefore, in order to use the inorganic fine particles (A) and the organic fine particles (B) in the commercial field, it is necessary to minimize the number of fine particles within the allowable haze range of the film. However, this makes it exhibit good slipperiness, but since the number of protrusions formed on the surface of the film is small, the film surface is very smooth. As a result, the surface area of the film becomes small, and therefore, the contact area of the film during the post-treatment is reduced, thereby causing a decrease in the bonding strength.

According to the invention, the inorganic fine particles (C) having different shapes and sizes from the inorganic fine particles (A) and the organic fine particles (B) are also added together with the fine particles (A) and (B). The inorganic fine particles (C) have an irregular block shape and have an average size of 0.5 to 2 μm. As such, when the inorganic fine particles (C) are also added, a large number of protrusions are formed, and the contact area is also increased, thereby improving the bonding strength. Further, such use of the inorganic fine particles (C) gives the film a more stable bending property than the case of using only the inorganic fine particles (A) and the organic fine particles (B). In addition, this situation can improve the slipperiness under high humidity. When large-sized inorganic fine particles are utilized, a large amount of fine particles cannot be used due to the haze of the thin film, and therefore, the number of fine particles is absolutely insufficient. As a result, good friction characteristics were exhibited at low humidity, but the friction coefficient was remarkably increased. However, when the inorganic fine particles (C) are added, a large number of small protrusions are formed even under high humidity, thereby reducing the increase in the friction coefficient.

The inorganic fine particles (A) and the organic fine particles (B) have an average particle size of 1 to 5 μm. If the average particle size is less than 1 μm, the effect of forming a matte after the film is formed is small, and thus the coefficient of friction cannot be effectively reduced. On the other hand, if the average particle size is larger than 5 μm, the film is broken due to a marked increase in the haze of the particles and the film.

The inorganic fine particles (C) have an average particle size of 0.05 to 2 μm and have an irregular block shape. If the average particle size thereof is less than 0.05 μm, the effect of the matte after the film is small is small, so that it is difficult to improve the bonding strength, and a large amount of agglomeration occurs during the preparation of the master batch, thereby reducing the dispersibility. On the other hand, if its average particle size is larger than 2 μm, the haze of the film is remarkably increased due to a large amount of particles. The inorganic fine particles (C) preferably have a particle size of from 1/100 to 1/25 of the inorganic fine particles (A). If the particle size of the inorganic fine particles (C) is larger than 1/25 of the inorganic fine particles (A), the haze of the film is remarkably increased, and since the inorganic fine particles (C) have a block shape, when the master batch is prepared or the film is produced, It is easy to have agglomeration. These massive structures cause defects in the film and, therefore, defects are produced when the cell bag is produced. On the other hand, if the particle size of the inorganic fine particles (C) is smaller than 1/100 of the particle size of the inorganic fine particles (A), a large amount of fine particle agglomeration occurs in the preparation of the master batch, thereby increasing the difficulty in preparing the master batch. Further, the nylon film used in the masterbatch combination preferably has a relative viscosity of 2.6 to 3.5 (measured by a 95% sulfuric acid method). If the relative viscosity is less than 2.6, the dispersibility of the particles is excellent, but when mixed with the nylon film base resin, the difference in viscosity is large. As a result, some of the network points that are not printed or adhesively coated are produced at the time of printing or adhesive coating after the film is produced, resulting in deterioration of the quality of the final product. On the other hand, if the relative viscosity is more than 3.5, the dispersibility of the particles is lowered, thereby increasing the difficulty of satisfying the physical properties required of the film.

Further, the present invention mainly uses zeolite, alumina, ceria, kaolin, Na ₂ O, CaO or the like as the inorganic fine particles (A) and inorganic fine particles (C), and an acrylic, styrene or anthrone. Polymer particles or the like are used as the organic fine particles (B). These may be combined singly or in combination when preparing the master batch.

The masterbatch prepared by using the inorganic fine particles (A), the organic fine particles (B), and the inorganic fine particles (C) preferably has a particle content of 0.5 to 30% by weight. If the content of the fine particles is less than 0.5% by weight, the amount of the master batch to be prepared is increased, thereby increasing the difficulty in maintaining the quality of the master batch, and also increasing the cost of processing the master batch, and thus increasing the production cost. On the other hand, if the content of the fine particles is more than 30% by weight, the dispersibility of the fine particles is deteriorated, and since the content of the fine particles is high, it is difficult to produce a masterbatch of uniform quality. Further, the dispersibility of the fine particles in the film is deteriorated, and the number of the film fine particles is difficult to control. Further, the optimum content of the above inorganic fine particles is 1600 to 13,000 ppm based on the total content of the film.

Further, 100 to 1000 ppm of inorganic fine particles (A), 1000 to 10000 ppm of organic fine particles (B), and 500 to 2000 ppm of inorganic fine particles (C) may be contained.

If the content of the inorganic fine particles (A) is less than 100 ppm, even if the content of the organic fine particles (B) having a large size is increased, the bending property is severely deteriorated. On the other hand, if the content of the inorganic fine particles is more than 1000 ppm, the haze of the film is remarkably increased without improving the bending property or the low friction coefficient characteristics and the manufacturing cost.

If the content of the organic fine particles (B) is less than 1000 ppm, in view of haze, even if a large amount of inorganic fine particles (A) having a large size is supplied, low friction characteristics are difficult to achieve. On the other hand, if the content of the organic fine particles (B) is more than 10,000 ppm, the slip property is too high so that bending is difficult, the haze of the film is remarkably increased, and the manufacturing cost is also increased.

If the content of the inorganic fine particles (C) is less than 500 ppm, printing and adhesion are severely deteriorated. On the other hand, if the content of the inorganic fine particles (C) is more than 2,000 ppm, the manufacturing cost is increased without improving the printing and adhesion.

The nylon film of the present invention is not limited by nylon 6, and may include a nylon biaxially stretched film. Generally, the nylon film used in the present invention has a suitable thickness of 5 to 50 μm, and the base resin used in the nylon film has a preferred relative viscosity of 3.0 to 3.6. If the relative viscosity of the base film is less than 3, the physical properties of the nylon film after manufacture are destroyed. On the other hand, if the relative viscosity of the base film is higher than 3.6, the base resin does not have good flow characteristics at the time of melt extrusion, and the tensile properties are insufficient, which cannot satisfy the desired physical properties.

SUMMARY OF THE INVENTION The present invention is directed to a nylon film having a low coefficient of friction and a low modulus, and which has a better effect in bag-type bag depth capability.

Hereinafter, the present invention will be described in detail by way of specific examples, but the invention is not limited to the following examples.

The physical properties of the film of the present invention were measured by the following methods.

1) Friction coefficient

Measurement method: American Society for Testing and Materials (ASTM) D1894

Instrumentation: friction test device (Toyoseiki, TR model)

Measurement conditions: Measuring the coefficient of friction of the corona treated surface of a nylon film

2) Modulus

Measurement method: American Society for Testing and Materials (ASTM) D882

Instrument used: British tensile strength testing machine 5566 (Instron 5566)

Measurement conditions: elongation rate 500mm/min, temperature 20°C, relative humidity 65%

Sample size: width 15mm, length 100mm

Determine the tensile stress to 2% stress after measurement according to the above method

3) Haze

Measurement method: American Society for Testing and Materials (ASTM) D1003

Use the instrument: color and color difference meter

(Nopon denshoku, 1001DP model)

Example 1

As shown in Table 1, 1 wt% of spherical alumina (aspect ratio, 1.02) was used as a component of the inorganic fine particles (A), and 5 wt% of polymethyl methacrylate beads (KOLON Diasphere) was used as organic fine particles. a component of (B), and 2% by weight of kaolin having irregular massive form as a component of the inorganic fine particles (C), mixed in a nylon 6 having a relative viscosity of 3.3 based on the total weight of the master batch, and by using a double helix The resulting extruder was used at 245 ° C using the resulting mixture to prepare a mixed masterbatch.

Next, according to the contents shown in Table 3, the mixed master batch was mixed into nylon 6 having a relative viscosity of 3.3. The resulting mixture was extruded at 265 ° C using a circular die while being biaxially stretched in a tube form at a draw ratio of 3 x 3 times, followed by heat setting, whereby a nylon film was produced. Further, an aluminum foil was attached to the manufactured film to produce a pouch form, and then the depth of the bag type was measured.

The results are reported in Table 3.

Example 2 to 6

Each of the mixed master batches was prepared in the same manner as in Example 1, except that the particle size and the contents of the inorganic fine particles (A), the organic fine particles (B), and the inorganic fine particles (C) were controlled as shown in Table 1, and the nylon was controlled. 6 is outside the relative viscosity.

Next, the mixed master batch was mixed into nylon 6 having a relative viscosity of 3.3, as shown in Table 3. The nylon film was produced by extruding the resulting mixture at 265 ° C using a circular die while being biaxially stretched in a tube form at a draw ratio of 3 x 3 times, followed by heat setting. Further, aluminum foil was attached to the manufactured film to produce a pouch type, and then the depth of the pouch type was measured and recorded in Table 3.

The results are reported in Table 3.

Example 7

The spherical synthetic zeolite, as a constituent component of the inorganic fine particles (A), is mixed into the nylon 6 having a relative viscosity of 3.3 as shown in Table 1 based on the total weight percent by weight of the master batch, so that it contains the contents as shown in Table 1. Masterbatch A was prepared using the resulting mixture by using a twin propeller extruder at 245 ° C, as in Example 1.

Polymethyl methacrylate beads (KOLON Diasphere), as a constituent of the organic fine particles (B), based on the total weight percent by weight of the masterbatch, are also mixed into the nylon 6 having a relative viscosity of 3.3 as shown in Table 1. This was made to contain the contents as shown in Table 1, and the resulting mixture was used to prepare Masterbatch B as in Example 1.

The block kaolin, as a constituent of the inorganic fine particles (C), is also mixed into the nylon 6 having a relative viscosity of 3.3 as shown in Table 1 so as to contain the components shown in Table 1 as shown in Table 1. The content, and the resulting mixture was used to prepare the masterbatch C.

Next, the three prepared master batches were mixed into nylon 6 having a relative viscosity of 3.3 as shown in Table 1. The nylon film was produced by extruding the resulting mixture using a circular die, as in Example 1, and biaxially stretching in a tubular form. Further, an aluminum foil was attached to the formed film to produce a pouch type, and then the depth of the pouch type was measured and recorded in Table 3.

The results are reported in Table 3.

Example 8 to 12

Each of the nylon films was produced in the same manner as in Example 7, except that the contents of the inorganic fine particles (A), the organic fine particles (B), and the inorganic fine particles (C) to be added as shown in Table 1 were verified. In addition, aluminum foil was applied to the formed film to produce a pouch type, and then the depth of the pouch type was measured and recorded in Table 4.

The results are reported in Table 4.

Compare examples 1 to 6

For each of the comparative examples, each master batch having a content as shown in Table 2 was prepared, and a master batch was used to manufacture a film, as in Example 1. The results are reported in Table 4.

Table 1

Method for preparing masterbatch (percentage (%) means weight percentage (wt%))

Table 2 (percentage (%) represents weight percent (wt%))

Table 3 (percentage (%) represents weight percent (wt%))

* The delamination between the aluminum foil and the comparative example 3 occurred in the production of the bag type.

Table 4 (percentage (%) represents weight percent (wt%))

* Comparative Example 6 cannot be used as a cell pouch due to high haze and a large number of particle aggregation defects.

As can be seen from the results of Tables 3 and 4, the nylon film produced by the present invention has a lower coefficient of friction and a lower modulus, as well as a better bag-type bag depth.

Claims (5)

A nylon film comprising: a plurality of inorganic particles (A) and a plurality of organic particles (B), each of the inorganic particles (A) and the organic particles (B) having an average particle size of 1 to 5 μm; a plurality of inorganic fine particles (C) having an average particle size of 0.05 to 2 μm, wherein the nylon film has a coefficient of friction of 0.05 to 0.3 according to ASTM D1894, a modulus range of 250 to 350 kg/cm ² according to ASTM D882, and according to ASTM D1003, the film has a haze of 10 to 50, and wherein the nylon film contains spherical inorganic particles (A) of 100 to 1000 ppm, spherical organic particles (B) of 1000 to 10000 ppm, and has inorganic particles (A) The irregularly shaped inorganic particles (C) of different sizes are 500 to 2000 ppm. The nylon film according to claim 1, wherein the inorganic fine particles (A) and the inorganic fine particles (C) are selected from the group consisting of zeolite, alumina, cerium oxide, kaolin, sodium oxide, and Calcium oxide, and the organic fine particles (B) are acrylic, styrene or fluorenone polymer fine particles. The nylon film according to claim 1, wherein each of the inorganic fine particles (A) and the organic fine particles (B) has a spherical shape, and the inorganic fine particles (C) have an irregular block. Shape. The nylon film according to claim 1, wherein the inorganic fine particles (C) have an average particle size of from 1/100 to 1/25 of the inorganic fine particles (A). The nylon film according to claim 1, wherein the nylon film is produced by extrusion using a circular die and biaxial stretching in a tubular manner.