JP2760991B2 - Polyamide film for packaging - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a packaging film, particularly to a polyamide film having good transparency, gas barrier properties and slip properties.

[Conventional technology]

Aliphatic polyamide films are widely used as packaging films, especially food packaging films, because of their excellent gas barrier properties, pinhole resistance, heat resistance, cold resistance, oil resistance, printability, and the like. On the other hand, a partially aromatic polyamide in which the acid component is an aromatic dicarboxylic acid and the diamine component is an aliphatic diamine or an alicyclic diamine is more excellent in transparency, oxygen barrier properties, flavor barrier properties, and heat sealing properties. Attention has been drawn as a packaging film material. However, such partially aromatic polyamides, particularly amorphous or low-crystalline partially aromatic polyamide films, have the disadvantage that they have poor slip properties and are likely to cause blocking, as compared with general-purpose aliphatic polyamide films. It was found that improvement was necessary for handling on an industrial scale.

Heretofore, some formulations of an aliphatic polyamide with a slip agent or an anti-blocking agent have been known, but no systematic study has been made on the improvement of the slip property of a partially aromatic polyamide. It has also been found that various inconveniences occur even if the prescription is applied as it is. For example, when the aliphatic polyamide formulation is applied as it is, the slip property is often insufficient, and when the addition amount of the slip agent or the like is increased to improve the slip property, the transparency of the film is reduced and the powder blowing phenomenon is caused. In some cases, troubles occurred. Also,
In that case, when the slip agent is to be blended in an industrially advantageous master batch system, in the granulation step of producing a master batch containing a high concentration of the slip agent, the screw of the extruder causes an idling phenomenon, and the Granulation sometimes became difficult. Further, even in a formulation satisfying the above-mentioned transparency and granulation properties, there is a problem that an eye is generated at the time of forming a film, which causes a problem that the film thickness becomes non-uniform, scratches occur, and the film is torn. Sometimes happened.

For example, erucamide and palmitamide are widely known as slip agents, but do not exhibit a sufficient slip effect on partially aromatic polyamides.
Also, Japanese Patent Application Laid-Open No. 61-64750 proposes to blend a bisamide with an aliphatic copolymerized polyamide,
For partially aromatic polyamide, even if such a bisamide alone is blended, a sufficient effect cannot be obtained unless it is used in a large amount, in which case the transparency is lowered and other disadvantages as described above are caused. I also found out. As a method for improving the slip property of polyamide, a method using two kinds of additives is known. For example, JP-A-56-151729 discloses that N, N'-ethylenebisstearylamide is added to an aliphatic copolymerized polyamide. And talc are shown, but it has been found that when this formula is applied to a partially aromatic polyamide, it is not preferable because a phenomenon occurs in the film formation.

[Means for solving the problem]

The present inventors have recognized that there are various problems to be solved in the slip property improvement of the partially aromatic polyamide film, and as a result of conducting many experiments, N,
By mixing N'-alkylenebisfatty acid amide and silica of a specific particle size at a fixed blending ratio, transparency is not impaired by a small amount of addition, granulation is carried out smoothly, and there is no occurrence of eyes during molding. It has been found that a polyamide film having excellent slip properties can be obtained.

That is, the present invention provides: (1) an acid component comprising terephthalic acid / isophthalic acid = 1/9 to 5
/ 5 (molar ratio) a mixture of terephthalic acid and isophthalic acid, wherein the diamine component is hexamethylenediamine: 50-100 parts by weight of a partially aromatic polyamide; and (2) a polyamide comprising 0-50 parts by weight of an aliphatic polyamide. (3) N, N'-methylenebisfatty acid amide or N, N'-
Ethylene bis fatty acid amide 0.05 to 0.5 parts by weight (4) The average particle size by the Coulter counter method is 1
It is a polyamide film for packaging containing 0.01 to 0.2 parts by weight of silica, which is 5 μm.

The partially aromatic polyamide of the present invention is a copolycondensation polyamide of hexamethylenediamine and terephthalic acid and isophthalic acid is a low-crystalline or non-crystalline polyamide, and is excellent in transparency, so that it is suitable as a packaging film. . In this copolycondensation polyamide, the ratio of terephthalic acid to isophthalic acid is 1/9 to 5/5, especially 2/8 to 4/6.
Polyamides in the range are suitable for the purposes of the present invention.

Although the partially aromatic polyamide can be used alone, it can also be used as a mixture with an aliphatic polyamide. As aliphatic polyamides, nylon 6, nylon 66,
Nylon 610, nylon 12, nylon 6.66 and the like can be mentioned, but nylon 6, nylon 66 and nylon 6.66 are particularly preferred.

The composition of the partially aromatic polyamide and the aliphatic polyamide is a mixture of a partially aromatic polyamide 50 to 100 parts by weight and an aliphatic polyamide 0 to 50 parts by weight,
Preferably, a composition comprising 60 to 100 parts by weight of a partially aromatic polyamide and 0 to 40 parts by weight of an aliphatic polyamide is suitable.

The fatty acid components of N, N'-methylenebisfatty acid amide or N, N'-ethylenebisfatty acid amide added to polyamide include caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid,
Oleic acid, elaidic acid and the like can be mentioned, and stearic acid and oleic acid are particularly preferable.

N, N'-alkylenebisfatty acid amides include N, N '
-Methylenebisstearic acid amide, N, N'-methylenebisoleic acid amide, N, N'-ethylenebisstearic acid amide and N, N'-ethylenebisoleic acid amide are preferred.

The addition amount of N, N'-methylenebisfatty acid amide or N, N'-ethylenebisfatty acid amide is 0.05 to 0.5 part by weight, preferably 0.15 to 0.3 part by weight, based on 100 parts by weight of polyamide. . If the addition is less than 0.05 part by weight, the effect of improving the slip property is insufficient, and if it is added more than 0.5 part by weight, the transparency is lowered and trouble during granulation is liable to occur.

Silica, which is another additive component, has an average particle size of 1 to 5 μm as measured by a Coulter counter method, and silica within this range is N, N′-methylenebisfatty acid amide or N, N When added to polyamide in combination with '-ethylenebisfatty acid amide, the slip properties can be improved without impairing the transparency of the polyamide film.

The amount of silica is 0.01 to 0.2 parts by weight based on 100 parts by weight of the polyamide, and the addition of 0.2 parts by weight or more impairs the transparency of the film.

If the amount is less than 0.01 part by weight, the effect of improving the slip property is small.

The method of compounding N, N'-methylenebisfatty acid amide or N, N'-ethylenebisfatty acid amide and silica with the polyamide is not particularly limited, and a known method is used, but it is mixed with polyamide pellets using a tumbler or the like. It is possible to adopt a method of melt-kneading with an ordinary extruder, or a method of preparing a polyamide masterbatch containing these additives at a high concentration, and mixing the additives at a predetermined ratio with a polyamide without additives at the time of film forming. .

There is no particular limitation on the method for producing the polyamide film,
Known methods such as a T-die method and a tubular method can be employed. The polyamide film of the present invention can be used as a multilayer film with another thermoplastic resin if necessary.

The polyamide film of the present invention can be used for food packaging, for example, meat such as raw meat and processed meat, dairy products, miso, pickles, and other foods.
It is suitable for use in packaging retort foods and the like, and as the innermost layer of paper containers for beverages such as juices.

The film of the present invention may contain other additives,
For example, an antioxidant, an antistatic agent, an antifogging agent, a weather stabilizer, and the like can be added.

〔The invention's effect〕

The polyamide film of the present invention has a remarkably improved slip property due to the addition of a small amount of a mixed additive, and furthermore, there is no decrease in transparency due to the addition of the additive and no troubles in granulation and film forming. It is a polyamide film for packaging excellent in ease.

 Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 95 parts by weight of a partially aromatic polyamide which is a copolycondensate of hexamethylenediamine as a diamine component and 30/70 mol% of terephthalic acid / isophthalic acid as a dicarboxylic acid component, and N, N'-ethylenebisstearic acid Amide (trade name: Armowax EBS beads manufactured by Lion Co., Ltd.) 4 parts by weight and an average particle size of 1.7 by a Coulter counter method.
One part by weight of silica (trade name, Mizukasil P-527 manufactured by Mizusawa Chemical Industry Co., Ltd.) was extruded at a temperature of 230 ° C. using a 30 mmφ twin screw extruder, and then the water-cooled strand was cut and pelleted. A master batch was obtained.

Next, the partially aromatic polyamide 10 was cast into a 30 mmφ extruder (screw type: full flight) of a cast film forming machine having a coat hanger type die having a width of 300 mm.
A blended product of 0 parts by weight and 5 parts by weight of the above master batch was supplied by a brible blend method, extruded at a temperature of 230 ° C., rapidly cooled by a metal roll, and formed into a 30 μm thick film.

Table 1 shows the results of evaluating the coefficient of friction as a slip material and the haze as transparency of the obtained film.

Comparative Example 1 Table 1 shows the results of evaluating the coefficient of friction and the haze of a 30 μm thick cast film obtained by molding the partially aromatic polyamide used in Example 1 in the same manner as in Example 1.

Comparative Example 2 95 parts by weight of the partially aromatic polyamide used in Example 1,
4 parts by weight of N, N'-ethylenebisstearic acid amide (trade name: Armowax EBS beads manufactured by Lion Co., Ltd.) and silica having an average particle size of 5.5 μm as measured by the Coulter counter method (trade name: Manville, supermarket) Floss)
A master batch was obtained by pelletizing 1 part by weight in the same manner as in Example 1.

Next, a 30 μm thick film formed by the same method as in Example 1 except that 95 parts by weight of the partially aromatic polyamide used in Example 1 and 5 parts by weight of the master batch were supplied by a dry blending method. Table 1 shows the results of evaluating the coefficient of friction and the haze.

Example 2, Comparative Examples 7 and 8 93 parts by weight of the partially aromatic polyamide used in Example 1, 6 parts by weight of N, N'-bisstearinamide or erucamide or palmitamide as a slipping agent, and a Coulter counter method A masterbatch was obtained by pelletizing 1 part by weight of silica having an average particle diameter of 1.7 μm in the same manner as in Example 1.

Next, a 30 μm thick film formed by the same method as in Example 1 except that 95 parts by weight of the partially aromatic polyamide used in Example 1 and 5 parts by weight of the master batch were supplied by a dry blending method. Table 1 shows the results of evaluating the coefficient of friction and the haze.

Comparative Example 3 98.2 parts by weight of the partially aromatic polyamide used in Example 1, 0.8 part by weight of N, N'-bisstearic acid amide, and 1 part by weight of silica having an average particle diameter of 1.7 μm by a Coulter counter method. A masterbatch pelletized in the same manner as in Example 1 was obtained.

Next, friction of a 30 μm thick film formed in the same manner as in Example 1 except that 95 parts by weight of the partially aromatic polyamide used in Example 1 and 5 parts by weight of the master batch were supplied by a dry blending method. Table 1 shows the results of evaluating the coefficient and haze.

Comparative Example 4 92 parts by weight of the partially aromatic polyamide used in Example 1,
An attempt was made to obtain a masterbatch obtained by pelletizing 7 parts by weight of N, N'-bisstearic acid amide and 1 part by weight of silica having an average particle size of 1.7 μm by a Coulter counter method in the same manner as in Example 1. Pelletization was impossible due to the screw idling phenomenon of the extruder.

Comparative Example 5 95.9 parts by weight of the partially aromatic polyamide used in Example 1, 4 parts by weight of N, N'-bisstearic acid amide, and 0.1 part by weight of silica having an average particle diameter of 1.7 μm by a Coulter counter method were used. A pelletized master batch was obtained in the same manner as in Example 1.

Next, friction of a 30 μm thick film formed in the same manner as in Example 1 except that 95 parts by weight of the partially aromatic polyamide used in Example 1 and 5 parts by weight of the master batch were supplied by a dry blending method. Table 1 shows the results of evaluating the coefficient and haze.

Comparative Example 6 91 parts by weight of the partially aromatic polyamide used in Example 1,
A masterbatch was obtained by pelletizing 4 parts by weight of N, N'-bisstearic acid amide and 5 parts by weight of silica having an average particle diameter of 1.7 μm by a Coulter counter method in the same manner as in Example 1.

Next, a 30 μm thick film formed by the same method as in Example 1 except that 95 parts by weight of the partially aromatic polyamide used in Example 1 and 5 parts by weight of the master batch were supplied by a dry blending method. Table 1 shows the results of evaluating the coefficient of friction and the haze.

Examples 3 and 4, Comparative Example 10 80 to 30 parts by weight of the partially aromatic polyamide used in Example 1 and 20 to 70 parts by weight of nylon 6 (trade name: CMP1021XF, manufactured by Toray Industries, Inc.) as an aliphatic polyamide were added at 40 mmφ. After extruding at a temperature of 230 ° C. using an extruder, a strand cooled by water cooling was cut into pellets to obtain a partially aromatic polyamide / nylon 6 mixture.

Next, an air-cooled inflation film having a 300 mφ die is supplied to a 40 mmφ extruder of a molding machine by dry blending 95 parts by weight of the above mixture and 5% by weight of a master batch obtained in the same manner as in Example 1. Then, a film having a thickness of 30 μm was formed.

Table 2 shows the results of evaluating the coefficient of friction and haze of the obtained film.

Comparative Example 9 A masterbatch was obtained in the same manner as in Example 1 except that talc (trade name: Tomura Sangyo High Filler 5000PJ) was used, and a film was formed. The film was uneven and the film thickness was not uniform, resulting in a film with poor appearance. In addition, when the size of the eyes was large, the film breakage occurred due to the portion, and it was difficult to form the film.

Comparative Example 11 In the masterbatch used in Example 1, 95 parts by weight of a partially aromatic polyamide and N, N'-
A pelletized masterbatch was obtained in the same manner as in Example 1 except that ethylene bisstearic acid amide (trade name: Armowax EBS beads manufactured by Lion Corporation) was used in an amount of 5 parts by weight.

96 parts by weight of the partially aromatic polyamide used in Example 1 and 4 parts by weight of the above master batch were blended in the same manner by a dry blending method, and the polyamide containing 0.2 part by weight of EBS was mixed with 100 parts by weight of the polyamide composition at 30 μm. Was formed, and the coefficient of friction and haze were measured. Table 1 shows the results.

Comparative Example 12 0.4 parts by weight of EBS per 100 parts by weight of the polyamide composition in the same manner as in Comparative Example 11 except that the mixing ratio of the partially aromatic polyamide and the master batch was changed to 92 parts by weight and 8 parts by weight in Comparative Example 11. A 30 μm film of the blended polyamide was formed, and the friction coefficient and haze were measured. Table 1 shows the results.

Comparative Example 13 In the master batch used in Example 1, N, N '
Silica having 99 parts by weight of partially aromatic polyamide and an average particle size of 1.7 μm by a coal tar counter method without adding ethylenebisstearic acid amide (trade name: Mizusuka P-527 manufactured by Mizusawa Chemical Industry Co., Ltd.) ) As 1 part by weight to obtain a masterbatch pelletized in the same manner as in Example 1.

In a similar manner, 95 parts by weight of the partially aromatic polyamide used in Example 1 and 5 parts by weight of the above master batch were blended by a dry blending method, and 0.05 part by weight of silica per 100 parts by weight of the polyamide composition and 30 μm of polyamide containing 0.05 part by weight of silica were blended. The film was formed, and the coefficient of friction and haze were measured. Table 1 shows the results.

Comparative Example 14 0.25 parts by weight of silica per 100 parts by weight of the polyamide composition in the same manner as in Comparative Example 13 except that the mixing ratio of the partially aromatic polyamide and the master batch was 75 parts by weight and 25 parts by weight in Comparative Example 13 Was formed, and the friction coefficient and haze were measured. Table 1 shows the results.

 The physical property measurement items in the examples were performed by the following methods.

(1) Transparency (Haze) The transparency was measured using an SM color computer manufactured by Suga Test Instruments.

(2) Slip Property (Coefficient of Friction) In the case of a cast molded film, the non-metal roll side of the film was rubbed against the outer surface of the film in the case of an inflation molded film under the following conditions, and the friction coefficient was measured.

Friction area: 60 × 60mm Friction speed: 150mm / min Friction load: 200g

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification code FI C08K 5: 205 3:36) (58) Investigated field (Int.Cl. ⁶ , DB name) C08L 77/06 C08L 77/02 C08K 5/205 C08K 3/36

Claims (1)

(57) [Claims] (1) Partially aromatic wherein the acid component is a mixture of terephthalic acid and isophthalic acid in a molar ratio of terephthalic acid / isophthalic acid = 1/9 to 5/5, and the diamine component is hexamethylenediamine. (3) N, N'-methylenebisfatty acid amide or N, N'-ethylenebisfatty acid amide of 0.05 to 100 parts by weight of polyamide consisting of 50 to 100 parts by weight of polyamide and 0 to 50 parts by weight of aliphatic polyamide 0.5 part by weight (4) The average particle size by the Coulter counter method is 1 to
A polyamide film for packaging containing 0.01 to 0.2 parts by weight of silica, which is 5μ.