KR19990042596A - Method of producing polyamide film - Google Patents

Abstract

The present invention is polymerized by adding 0.1 to 5.0% by weight of organic monoamine and organic monocarboxylic acid as inorganic particles and end-controlling agent with respect to polyamide resin 100 and adding 10 to 1000 ppm of magnesium compound as catalyst during the polymerization of polyamide resin. The present invention provides a method for producing a polyamide film, which is then extruded by a Ti-die method or an inflation method. A die-line and fisheye is reduced, so that a polyamide film having excellent printability and excellent transparency and slipperiness can be obtained. You will get

Description

Method of producing polyamide film

The present invention relates to a method for producing a polyamide film having excellent melt stability, good appearance, and improved transparency and slip properties. More specifically, organic monoamine and organic monocarboxylic acid may be used as a polymer end-controlling agent in lactams. The present invention relates to a method for producing a polyamide film having excellent appearance, improved transparency and slippery properties, characterized in that it is added and polymerized under a magnesium compound catalyst, and then produced by a Ti-die method or an inflation method.

Polyamide film has excellent gas barrier properties, mechanical properties, and thermal properties compared to other materials, so it is not only used for food packaging but also as a single layer film through printing process or as a laminate film of other resin film, laminated film or other materials. have.

In general, polyamide films are usually produced by extruding a polyamide polymer under appropriate conditions. When the polyamide resin is continuously extruded, volatile substances such as monomers and oligomers are formed and adhered to the die surface, and the attached material is exposed to high temperature air. The problem of oxidation and degeneration of carbides occurs. In addition, carbides that accumulate on the die surface disrupt the flow of molten polyamide and are mixed into the polyamide melt to produce die-lines and increase fish eyes, resulting in poor film appearance and film Worsens the transparency and slipperiness.

In the polyamide film, it is difficult to print uniformly on the film when the transparency is poor, and when the slip property is poor, adhesion between the films occurs during the printing process, that is, blocking occurs, which lowers work and print deformation occurs when printing in multicolor printing. Done. Therefore, the transparency and slipperiness of the polyamide film becomes an important characteristic in terms of the productivity of the film as well as the quality and product value.

As a method for improving the slip property of a polyamide film, Japanese Patent 53-45226 proposes a method of blending polyethylene, and Japanese Patent 54-4741 proposes a method of combining inorganic particles having high surface activity. However, the method of blending polyethylene has the disadvantage of lowering the transparency of the film, which is a conventional problem, and the method of combining inorganic particles deteriorates the melt stability of the polyamide resin, resulting in defects in the form of particles called diessia and die line. There is a disadvantage in that it is difficult to continuously produce a film having a good appearance. In addition, when only silica is mixed as an inorganic particle in the combination of the inorganic particles, a film having a relatively good transparency and slipperiness can be obtained, but there is a disadvantage in that die lines and fisheye are easily generated.

An object of the present invention is to overcome the conventional problems as described above, to provide a method for producing a polyamide film excellent in transparency and slip properties without die line generated during extrusion, reduced fisheye.

That is, the present invention adds 0.1 to 5.0% by weight of organic monoamine and organic monocarboxylic acid as inorganic particles and terminal control agent to the polyamide resin 100, and 10 to 1000 ppm of magnesium compound as a catalyst during polymerization of the polyamide resin. It is to provide a method for producing a polyamide film, characterized in that the polymerization by extrusion.

Hereinafter, the present invention will be described in detail.

The monomers used in the polymerization of the polyamide resin of the present invention are preferably lactams or ω-amino acids. As the lactams, ε-caprolactam, capryllactam, lauryllactam, α-pyrrolidone and α-py Ferridone and the like are preferable, and as the? -Amino acids, 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid and the like are preferable.

Inorganic particles added to improve the slip properties of the present invention may be either wet silica or dry silica, having a specific surface area of 50 m 2 / g or more according to the BET method, and an oil absorption amount measured according to JIS K 5101. It is preferable that it is more than the above, 0.1-0.2 weight part is used with a magnesium compound, an organic monoamine, or a magnesium compound, and an organic monocarboxylic acid with respect to 100 weight part of polyamide resins.

In addition, the magnesium compound used as a catalyst in order to improve the slip properties and thermal stability in the present invention is selected from the group consisting of magnesium acetate, magnesium oxide, magnesium iodide, magnesium stearate, magnesium chloride 10-1000 ppm is used with respect to polyamide. If the added amount of the magnesium compound is less than 10ppm, the die line suppression effect is inadequate, and if it exceeds 1000ppm, the die line does not occur, but the physical properties of the film is reduced.

Monoamines and monocarboxylic acids used in the present invention are added as a sock end stabilizer of a polyamide chain structure in order to prevent a decrease in polymerization viscosity and occurrence of nonuniformity, which may occur when a magnesium compound is used alone as a catalyst. Monoamine is preferably butylamine, isopropylamine, hexylamine, octylamine, dodecylamine, benzylamine, cyclohexylamine and the like, and monocarboxylic acids include acetic acid, propionic acid, butyric acid, caproic acid and capric acid. , Benzoic acid and the like are preferable.

In addition, the method of adding the monoamine and monocarboxylic acid mentioned above is a polymerization step of one selected from silica and magnesium compounds and one selected from the above-mentioned monoamine in a ratio of 0.1 to 5.0% by weight relative to the polyamide It is preferred to polymerize together by adding together or polymerizing monocarboxylic acids together with silica and magnesium compounds instead of monoamines or by adding together silica, magnesium compounds, monoamines and monocarboxylic acids.

If the amount of the monoamine and the monocarboxylic acid is less than 0.1% by weight, the polymerization viscosity nonuniformity is not improved. When the amount of the monoamine and the monocarboxylic acid is more than 5.0% by weight, the film properties are deteriorated due to the die line phenomenon and the polymerization viscosity.

In addition, as a result of adding the organic monoamine and the organic monocarboxylic acid to the polymerization step, by polymerizing an appropriate amount of monoacid or monoamine in the presence of a magnesium compound, the polymer viscosity change value (Δη _rel ) of the polymer chip and the film forming film is 0.5 or less. Not only is it easily suppressed and increases the reaction rate of the polymer, but also achieves a substantial reaction equilibrium during the film forming process to obtain uniform and good physical properties.

Here, the relationship between the viscosity change value (Δη _rel ) of the polymer and the slip property and transparency is described. In order to obtain a sufficient modification effect for melt extrusion, the polymer viscosity change value (Δη _rel ) after extrusion can be expressed by the following equation.

Δη _rel = (1% solution made of polymer chip and 98% sulfuric acid-relative viscosity of sulfuric acid)-(1% solution made of film and 98% sulfuric acid-relative viscosity of sulfuric acid)

It is required to be about 0.5 or less. If a high viscosity polymer is used or the above conditions are not satisfied, the extruder does not substantially reach equilibrium during the residence time, and thus die-line phenomenon and denaturation caused by a large amount of monomers and oligomers are caused during extrusion. Due to the large amount of fisheye generated in the film, the appearance of the film is deteriorated, and it is difficult to manufacture a film having excellent printability due to a decrease in slip property.

In the present invention, in order to further improve the lubricity of the film in addition to the above components, the film can be prepared by adding ethylene bissteramide (EBS) to the polyamide resin obtained in the polymerization.

In order to uniformly disperse the magnesium compound, monoamine and monocarboxylic acid in the polyamide film, a method of pre-mixing the polymer chip and each additive with a separate mixer or blender, or during polymerization or directly in the extruder is preferable. The method of adding during polymerization is most preferred for uniformity of dispersion.

In addition, the polyamide polymer prepared according to the present invention is to be produced into a film through the Ti-die method or inflation method.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Examples 1-7

100 parts by weight of caprolactam, 0.2 parts by weight of silica, 2 parts by weight of water and the composition of the organic monoamine, the organic monocarboxylic acid and the magnesium compound were changed as shown in Table 1, put into a polymerization reactor and polymerized at 260 ° C. for 6 hours, After removing the internal pressure and reacted for 4 hours at a reduced pressure of 220 torr (torr) to prepare a polyamide having a constant relative viscosity, each relative viscosity is shown in Table 1. After extracting and drying the obtained polyamide chip, resins N1 to N7 containing EBS in an amount of 0.1% by weight with respect to each polyamide resin were 25 mm thick at a resin temperature of 270 ° C. and a cooling exit temperature of 40 ° C. using an extruder having a diameter of 40 mm. Film was formed into a film. In order to visually observe the presence or absence of die lines and the number of fisheyes using the film 4 hours after the start of film formation, and to evaluate the transparency and slip properties using the film having passed 1 hour after the start of film formation, The static friction coefficient was measured and shown in Table 2.

Comparative Examples 1 to 3

100 parts by weight of caprolactam, 0.2 parts by weight of silica, 2 parts by weight of water and the monoamine or monocarboxylic acid compound as shown in Table 1 were each added to a polymerization reactor and polymerized at 260 ° C. for 6 hours. The reaction was carried out under reduced pressure of Thor for 4 hours to prepare a polyamide having a constant relative viscosity, each of which is shown in Table 1. Thereafter, the resins N8 to N10 blended with EBS were prepared in the same manner as in Example, and the physical properties thereof were shown in Table 2 below.

Magnesium addition amount (ppm) Monocarboxylic acid ^a) addition amount (weight%) Monoamine ^b) Amount added Polymerization Viscosity (RV) Viscosity Difference between Chip and Film Example 1 50 ^c) 0.5 0.5 2.70 0.1 Example 2 100 ^c) 1.5 - 2.65 0.2 Example 3 250 ^c) - 2.0 2.63 0.3 Example 4 100 ^c) 2.0 2.0 2.65 0.2 Example 5 200 ^d) 1.0 2.0 2.67 0.2 Example 6 500 ^d) 2.0 1.0 2.62 0.5 Example 7 100 ^f) 0.5 0.5 2.65 0.4 Comparative Example 1 - - - 2.72 0.6 Comparative Example 2 - 5.0 - 2.68 0.5 Comparative Example 3 - - 5.0 2.66 0.6

a) acetic acid b) benzylamine c) magnesium acetate d) magnesium chloride

f) magnesium stearate

Haze (%) Static friction coefficient Die line presence Fishia () Example 1 N1 2.1 0.42 radish 3 Example 2 N2 2.0 0.42 radish 5 Example 3 N3 2.5 0.40 radish 6 Example 4 N4 3.0 0.50 radish 10 Example 5 N5 2.3 0.44 radish 10 Example 6 N6 2.6 0.47 radish 13 Example 7 N7 2.8 0.41 radish 11 Comparative Example 1 N8 3.6 0.65 U 20 Comparative Example 2 N9 3.0 0.60 U 15 Comparative Example 3 N10 3.0 0.55 U 17

Property measurement method

(1) Haze: It measured using haze meter (Tokyo Color Co., Ltd.).

(2) Slipperiness: The static friction coefficient was measured by parallel movement under the condition of 65% relative humidity and 23 ° C temperature.

(3) Die line and fisheye: The film was cut into 300x300 mm, the part was visually observed, and the number of fisheye of 40 micrometers or more was measured.

According to the present invention, by using a magnesium compound in combination with monoamine and mono carboxylic acid, it is possible to prevent dielines and improve melt stability, which reduces printability. Improving the properties makes it possible to obtain a polyamide film having good printability and improved physical properties.

Claims (3)

At the time of polymerization of the polyamide resin, 0.1 to 5.0% by weight of an organic monoamine and an organic monocarboxylic acid as inorganic particles and an end regulator are added to the polyamide resin 100, and 10 to 1000 ppm of a magnesium compound is added as a catalyst, followed by extrusion. Method for producing a polyamide film, characterized in that. According to claim 1, wherein the organic monoamine is selected from the group consisting of butylamine, isopropylamine, hexylamine, octylamine, dodecylami, benzylamine, cyclohexylamine, wherein the organic mono carboxylic acid is acetic acid , Propionic acid, butyric acid, caproic acid, capric acid, benzoic acid and the like. The method of claim 1, wherein the magnesium compound is at least one selected from the group consisting of magnesium acetate, magnesium oxide, magnesium iodide, magnesium stearate, and magnesium chloride.