WO1997038043A1

WO1997038043A1 - Polyamide film composition

Info

Publication number: WO1997038043A1
Application number: PCT/KR1996/000047
Authority: WO
Inventors: Gi Sang Song; Jin Sa Kim; Bo Kyoung Jeon
Original assignee: Kolon Industries, Inc.
Priority date: 1996-04-08
Filing date: 1996-04-08
Publication date: 1997-10-16

Abstract

The present invention relates to a polyamide film composition having excellent slipperiness and excellent workability because breakage thereof hardly occurs. According to the present invention, a polyamide film composition comprising aliphatic or aromatic diamine, dicarboxylic acid and amino acid, wherein the composition additionally comprises 0.01 - 2.0 % by weight of silicon dioxide having mean particle diameter of 0.5 - 10 νm and oil absorption ability of 200 ml/100 g or less is provided.

Description

TITLE OF THE INVENTION

POLYAMIDE FILM COMPOSITION

TECHNICAL FIELD

The present invention elates to a polyamide film composition, more specifically, a polyamide film composi- tion having excellent slipperiness and excellent workabili¬ ty with no breakage occurred.

BACKGROUND ART

Besides the own characteristics of each plastic film, an additional requirements to the characteristics are high¬ speed productivity, and an easiness for the post-processing such as slitting, printing and lamination. Even though being a film having excellent quality, there occurs various problems in the industrial use unless it has high productivity and can be readily post-processed.

However, as the hygroscopicity of the polyamide film is increasing, the surface adsorbed water is increasing, and as a result, the slipperiness of the film is deterio- rated. The deterioration of slipperiness causes a serious problem in the post-processing such as slitting, printing and lamination, whereby resulting in a prominent deteriora¬ tion of workability and a reduce of yield owing to the occurrence of inferior goods to raise the cost for produc- tion. Thus, slipperiness of polyamide film is an important property which controls the difficulty of the post-process¬ ing.

Various methods have been developed to enhance the slipperiness of polyamide film, and the methods are gener¬ ally divided into two groups, of which the one is to reduce the contact area by making minute unevennesε on the sur¬ face, and the other is to heterogenize the surface by using a highly slippery material.

Examples of the former group include the methods to provide unevenness to the surface by globular crystal growing by slow cooling in extruding film formation (Japa¬ nese Patent Publication No. Sho 51-7708, No. Sho 48-16986), or by crystal growing caused by an addition of crystal seeds(Japanese Patent Publication No. Sho 52-41925) , or the method by spreading silica or talc micro-powder to the film surface(Japanese Patent Publication No. Sho 48-33991), or incorporating the powder into the raw material so that the powder is to be protruded on the film surface after the film formation. Besides, methods of emboss processing, mat processing, surface roughening by chemicals have been known.

However, these methods cause some problems during the manufacturing or processing steps, or quality problems.

More specifically, the method for globular crystal growing by slow cooling restricts the condition for the film formation and deteriorates workability, the spreading micro-powder method noticeably deteriorates the working environment and has difficulty to control the spreading quantity of the micro-powder. In the method for film formation by mixing foreign material, it is difficult to disperse homogeneously not to cause a breakage at the stretching. The emboss processing, mat processing or treatment with chemical agent includes complicated steps to cause the cost-rise, and deteriorates the transparency and the surface gloss.

As the latter methods, a process of incorporating highly slippery foreign materials such as wax, biεamide or the like to form a film, or directly coating on the surface has been known. However, these methods may cause adhesion inferiority during the course of printing or laminating. On the other hand, an attempt to overcome the disad¬ vantages of the prior art by adding silica during the preparation of polyamide film has been tried in Japanese Patent Publication sho 52-41925, however, satisfactory results could not be obtained because of problems such as clogging of filter, occurrence of cake, breakage, and bad workability.

DISCLOSURE OF INVENTION

Under such circumstances, the present inventor has performed intensive study in order to solve the problems of the prior art as described above, and, as a result, found the fact that the oil absorption ability, the mean parti- cle diameter and the addition amount of silicon greatly affect on the slipperiness of the film, and thus completed the present invention of a polyamide film composition which has excellent slipperiness and no breakage during the work to give excellent workability. The present invention relates to a polyamide film composition which has improved slipperiness by virtue of the unevenness on the film surface by preparing the film from a polymer mixture admixed with silicsa as an anti¬ blocking agent. More specifically, the present invention relates to a polyamide film composition of improved slip¬ periness, comprising aliphatic or aromatic diamine, dicarb¬ oxylic acid and amino acid, wherein the composition addi¬ tionally comprises 0.01 - 2.0 wt% by weight of silicon dioxide having mean particle diameter of 0.5 - 10 μm and oil absorption ability of 200 ml/100 g or less.

In the preparation of this film, what is important is to perform intimate dispersion of the silica particles added so as to avoid film breakage during the process and other problems in workability.

Oil absorption ability of silica is preferably not more than 200 ml/100 g. If oil absorption ability is more than 200 ml/100 g, a viscous filtrate may clog the filter and form a hard cake so that the filtration can not be per¬ formed when the water slurry in which silica have been dis¬ persed is added and passed through 800 mesh filter. On the other hand, if the particle has oil absorption ability of 200 ml/100 g or less, the particles hardly aggregate between themselves and make a good dispersion, thus there happens no problem of filtration.

Mean particle diameter of silica may be 0.5-10 μm, preferably 1 - 5 μm. If mean particle diameter is less than 0.5 μm, the effect of forming unevenness on the surface after film formation may be reduced so that im¬ provement of friction coefficient cannot be expected. On the other hand, if the diameter is more than 10 μm, the possibility of existence of large particles is increased so that the risk of breakage during the film formation may be increased.

The amount of silica to be added is preferably 0.01 - 2.0 wt% by weight. If the amount is less than 0.01 % by weight, the formation of unevenness is insufficient so that improvement of friction coefficient cannot be expected. On the other hand, if the amount is more than 2.0 wt% by weight, a serious problem occurs because the possibility of aggregation and that of existence of large particles may be increased, whereby breakage may be caused. BEST MODE FOR CARRYING OUT THE INVENTION

Here-in-after, the present invention will be described in more detail, referring to the Examples and Comparative Examples. However, it should be noted that the present invention is not restricted to these Examples.

Example 1 Polyamide 6 resin, which had been polymerized by adding 0.2 wt% by weight of silica particles having mean particle diameter of 2.0 μm and oil absorption ability of 170 ml/lOOg to e-caprolactam, had relative viscosity of 3.45 measured by 96% sulfuric acid method. The resin was melted at 260°C, extruded through a loop die, and water cooled to prepare a non-stretched sheet. The sheet was stretched by stretching ratio 3.0 in length and width directions by simultaneous biaxial stretching with tubular type to prepare a film. The stretched film thus obtained was thermally set in a heat treatment roll and an oven at 140 - 210°C to prepare the film as a final product.

Example 2

The procedure same as Example 1 was repeated with a polyamide 6 resin, which had been polymerized by adding 0.1 wt % by weight of silicon dioxide particles having mean particle diameter of 3.0 μm and oil absorption ability of

100 ml/lOOg to e-caprolactam to prepare a film.

Comparative Example 1

The procedure same as Example 1 was repeated with a polyamide 6 resin, which had been polymerized by adding 0.2 wt% by weight of silicon dioxide particles having mean particle diameter of 2.0 μm and oil absorption ability of 300 ml/lOOg to e-caprolactam to prepare a film.

Comparative Example 2

The procedure same as Example 1 was repeated with a polyamide 6 resin, which had been polymerized by adding 0.2 wt% by weight of silicon dioxide particles having mean particle diameter of 0.3 μm and oil absorption ability of

300 ml/lOOg to e-caprolactam to prepare a film.

Comparative Example 3

The procedure same as Example 1 was repeated with a polyamide 6 resin, which had been polymerized by adding 0.1 wt% by weight of silicon dioxide particles having mean particle diameter of 12 μm and oil absorption ability of 300 ml/lOOg to e-caprolactam to prepare a film.

Comparative Example 4

The procedure same as Example 1 was repeated with a polyamide 6 resin, which had been polymerized by adding 0.005 wt% by weight of silicon dioxide particles having mean particle diameter of 3.0 μm and oil absorption ability of 300 ml/lOOg to e-caprolactam to prepare a film.

Comparative Example 5 The procedure same as Example 1 was repeated with a polyamide 6 resin, which had been polymerized by adding 3.0 % by weight of silicon dioxide particles having mean parti¬ cle diameter of 2.0 μm and oil absorption ability of 100 ml/lOOg to e-caprolactam to prepare a film.

Experiments

Methods and Results

Friction coefficient, film breakage frequency and Haze of each film prepared by the Examples and Comparative Examples described above were measured. The results are shown in Table 1 and Table 2 below :

Table 1

Ex. Mean particle oil Amount 50% RH No. diameter(μm) absorption added Friction ability (wt%) coefficient (ml/lOOg)

Ex.l 2.0 170 0.2 0.34/0.29

Ex.2 3.0 100 0.1 0.37/0.33

Comp. 2.0 300 0.2 0.63/0.60 Ex.l

Comp. 0.3 300 0.2 0.89/0.90 Ex.2

Comp. 12.0 300 0.1 0.38/0.35

Ex.3

Comp. 3.0 300 1.48/1.80 Ex.4 0.005

Comp. 2.0 100 3.0 0.25/0.24 Ex.5

Table 2

Ex. 70% RH Filtration Film Haze No. Friction Breakage coefficient

Ex.l 0.48/0.43 Good < 1/day 3.0

Ex.2 0.5/0.45 Good < 1/day 2.5

Comp. 1.08/0.98 Caked < 3/day 2.0

Ex.l

Comp. 1.48/1.3 Caked < 2/day 0.5 Ex.2

Comp. 0.47/0.41 Caked < 5/day 6.0

Ex.3

Comp. 2.75/2.90 Good < 1/day 0.4

Ex.4

Comp. 0.28/0.29 Caked Continuous 70 Ex.5 breakage

[Methods for Measurements]

1) Mean particle diameter : Coulter Counter Method 2) Oil absorption ability : JIS K5101

3) Friction Coefficient : ASTM D1894

(In case of low friction coefficient, slipperiness is good, while in case of high friction coefficient, slipperiness is bad. ) 4) Haze : ASTM D1003

Results

In Examples 1 and 2, films were prepared according to the present invention using silicon oxide of certain mean particle diameter, oil absorption ability in a predeter- mined amount. The films had improved slipperiness with low friction coefficient, good filterability, and excellent workability with less than once/day of film breakage.

In Comparative Example 1 in which oil absorption ability of silicon oxide exceeded the predetermined range, friction coefficient increased to be compared to Examples 1 and 2 so that slipperiness was lowered, cake occurred during the filtration, and workability was deteriorated (less than three times per day of film breakage) compared to the present invention.

In Comparative Example 2 in which both particle diameter and oil absorption ability were out of the prede¬ termined range of the present invention, slipperiness was bad because of high friction coefficient owing to the small particle size, cake occurred during the filtration owing to high oil absorption ability, and the frequency of film breakage was high.

In Comparative Example 3 in which both oil absoptivity and mean particle diameter of silicon dioxide were out of the predetermined range of the present invention, cake occurred during the filtration and Haze was increased to deteriorate transparency of the film though slipperiness had been improved with low friction coefficient. In addition, film breakage frequently occurred to deteriorate the workability.

In Comparative Example 4 in which both oil absoptivity and the amount of silicon dioxide were out of the predeter¬ mined range of the present invention, friction coefficient was highly raised to lower the slipperiness though the mean particle size was within the range.

In Comparative Example 5 in which the amount of silicon dioxide had been increased, slipperiness was im¬ proved with lower friction coefficient, however the work¬ ability was deteriorated by caking during the filtration and continuous film breakage, and transparency of the film was also deteriorated. Thus, it was noted that the amount of silicon dioxide affects on the film formation.

What is demonstrated by the results of measuring friction coefficient, frequency of film breakage and Haze of the films prepared according to the Examples and Compar¬ ative Examples is that the silicon dioxide having mean particle diameter of 0.5 - 10 μm and oil absorption ability of 200 ml/lOOg or less should be added in an amount of 0.01 - 2.0 wt% by weight when it is added in order to improve the slipperiness of the polyamide film.

Thus, the polyamide films prepared according to the present invention has higher slipperiness than conventional films. In addition, high-speed productivity is achieved, post-processing such as slitting, printing and lamination are facilitated, and workability is improved with no breakage occurred, according to the present invention.

Claims

WHAT IS CLAIMED IS :

1. A polyamide film composition comprising aliphatic or aromatic diamine, dicarboxylic acid and amino acid, wherein the composition additionally comprises 0.1 - 2. Owt % by weight of silicon dioxide having mean particle diame¬ ter of 0.5 - 10 μm and oil absorption ability of 200 ml/100 g or less.

2. The polyamide film composition according to claim 1, wherein the mean particle diameter of silicon dioxide is 1 - 5 μm.