JPH11349808A - Polyamide resin composition for oriented film and oriented film prepared therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition for an oriented film being excellent in mechanical strengths, heat resistance, chemical resistance, etc., and having low transparency. SOLUTION: There is provided a polyamide resin composition for an oriented film, being a polyamide resin composition containing 100 pts.wt. polyamide resin and 0.5-5 pts.wt. amorphous zeolite, wherein the polyamide resin comprises 60-100 wt.% polyamide-forming units (nylon 6 units) comprising ε-caprolactam and 0-40 wt.% polyamide-forming units (nylon 66 units) comprising adipic acid and hexamethylenediamine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyamide resin composition for a stretched film, and more particularly to a polyamide resin composition for a stretched film capable of being biaxially stretched and a stretched film comprising the polyamide resin composition. is there.

[0002]

2. Description of the Related Art Polyamide resins are excellent in mechanical properties, heat resistance, chemical resistance, abrasion resistance and the like, and are often used for films and the like. Stretched films made from polyamide resin are excellent in gas barrier properties, mechanical properties, thermal properties, etc., so they are mainly used for food packaging, single-layer films, multilayer films, laminated films with other materials, biaxial It is used for a wide range of applications as a stretched film. Such a stretched film made of a polyamide resin is usually transparent, but there is a demand for a film having reduced transparency, for example, because it is not preferable to see the packaging material for waste in medical treatment or to see the contents.

As a method of reducing the transparency of a film, there is a method of blending various inorganic pigments such as carbon black and titanium white and inorganic filler particles. However, in the case of using an inorganic pigment, there is a problem that the influence of the previous material remains at the time of grade switching, and it takes a long time to switch the production grade. Further, when inorganic filler particles are used, there is a problem that the film is broken when the film is stretched, and it has been difficult to obtain a stretched polyamide film having excellent strength and heat resistance and low transparency.

[0004]

An object of the present invention is to provide a polyamide resin composition for a stretched film having excellent mechanical strength, heat resistance, chemical resistance and the like and low transparency.
Another object of the present invention is to provide a stretched film comprising the polyamide resin composition.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the present invention is that amorphous zeolite is added to 100 parts by weight of a polyamide resin.
A polyamide resin composition containing 5 to 5 parts by weight, wherein a polyamide-forming unit (6 units of nylon) composed of ε-caprolactam in the polyamide resin is 60 to 60 parts by weight.
The polyamide resin composition for a stretched film is 100% by weight, and the polyamide-forming unit (66 units of nylon) composed of adipic acid and hexamethylenediamine is 0 to 40% by weight.

Hereinafter, the present invention will be described in detail. In the composition of the polyamide resin in the present invention, the polyamide-forming unit composed of ε-caprolactam (hereinafter, also referred to as nylon 6 unit) is 60 to 100% by weight, and the polyamide-forming unit composed of adipic acid and hexamethylenediamine (hereinafter, referred to as nylon 6 unit). , Nylon 66 units).
0% by weight. When a plurality of polyamide resins are used, the resin composition in the mixture thereof may be within the above range. When the proportion of the nylon 6 units is less than 60% by weight, the specific haze value of the film becomes smaller than 1.0, the transparency becomes high, and the contents become clear when the bag is formed. Nylon 6 in polyamide resin
The ratio of units to 66 units of nylon is preferably 65 to 1
00% by weight / 0 to 35% by weight, more preferably 7% by weight.
5 to 100% by weight / 0 to 25% by weight.

The polyamide resin in the present invention includes:
Preferably, a polyamide resin obtained by polymerizing ε-caprolactam (6 nylon), a copolymerized polyamide resin obtained by polymerizing ε-caprolactam and adipic acid and hexamethylenediamine (6/66 copolymerized nylon), or a blend thereof And the like. As the polyamide resin giving 6 units of nylon, 6 nylon, 6/66
Copolymer nylon and the like. Examples of the polyamide resin giving 66 units of nylon include 6/66 copolymer nylon and 66 nylon, and preferably 6/66
Copolymer nylon is exemplified.

The relative viscosity of a polyamide resin is determined according to JIS K
According to 6810, it is preferably 1.5 to 6.0 when measured at a concentration of 1% in 98% sulfuric acid and a temperature of 25 ° C. If the relative viscosity is less than 1.5, mechanical strength tends to be insufficient,
If it exceeds 6.0, workability tends to decrease. The relative viscosity of the polyamide resin is more preferably 2.0 to 5.5, and most preferably 3.0 to 5.0. When a plurality of polyamide resins are used, the relative viscosity of the mixture is preferably within the above range.

The amorphous zeolite in the present invention includes a zeolite that is amorphous as measured by an X-ray method. When a zeolite having a crystal structure as measured by the X-ray method is used, stretching stability is extremely reduced, and stretching breakage is likely to occur frequently. The shape of the amorphous zeolite is not particularly limited, but an amorphous zeolite having a more polygonal shape than a spherical shape is preferable for promoting translucency and preventing the amorphous zeolite from falling off the film.

The oil absorption of amorphous zeolite is determined according to JIS K
-5101 method, preferably 1 to 70 ml / 1
00 g. If the oil absorption is too low, the stretching stability will be reduced, and the filler will fall out of the film, contaminating the guide roll or adhering to the filler.If the oil absorption is too high, the haze will not increase when the film is stretched, and the opacity will not be high. Will be enough. The oil absorption is more preferably 5 to 70 ml / 100 g.

The content of the amorphous zeolite is 0.5 to 5% by weight based on 100 parts by weight of the polyamide resin. If the content is less than 0.5% by weight, the specific haze value becomes small and the film becomes transparent. If the content exceeds 5% by weight, stretching breakage is apt to occur, and the filler is liable to fall off.
The content of the amorphous zeolite is preferably 1.0 to 3.5% by weight, more preferably 1.5 to 2.8% by weight, based on 100 parts by weight of the polyamide resin.

In the polyamide resin composition for a stretched film of the present invention, various fillers can be blended in addition to zeolite as long as the effects of the present invention are not impaired. Examples of the filler include silica, talc, kaolin, barium sulfate, calcium carbonate, and the like, and a glass fiber called a milled fiber having a fiber length of 100 μm or less can also be used. The shape of the filler is not particularly limited, but is preferably a polygonal shape rather than a spherical shape in order to promote translucency and prevent the filler from falling off the film.

As a method of adding zeolite to a polyamide resin, a method of directly blending a predetermined amount of zeolite particles with a polyamide resin and melt-kneading the same, and a method of adding a high concentration of zeolite particles to a polyamide resin and melt-kneading the zeolite. A method in which a high-content pellet is diluted with a polyamide resin during film formation and used (master batch method), and a method in which zeolite is added during polymerization of the polyamide resin (polymerization internal addition method). The masterbatch method or the internal polymerization method is preferred for improving the film quality and obtaining stable film formability.

In the polyamide resin composition of the present invention, various additives such as hindered phenol,
Antioxidants such as phosphate esters and phosphite esters,
It may contain a weather resistance improver such as a benzotriazole compound, an antistatic agent, a lubricant, a plasticizer, and the like. It is also possible to increase the specific haze value by adding a coloring agent such as an inorganic pigment, but it is necessary to extend the color change time of the extruder during production and to install a dedicated line. Therefore, when using a coloring component such as an inorganic pigment, the content of the coloring agent,
It is preferably at most 1 part by weight, more preferably at most 0.1 part by weight, based on 100 parts by weight of the polyamide resin.

The stretched film of the present invention can be obtained by a known film forming method using the above-mentioned polyamide resin composition. Examples of the film forming method include a T-die method and an inflation method. As the stretching method, any method known to those skilled in the art can be applied, and examples thereof include a uniaxial stretching method and a simultaneous or sequential biaxial stretching method. The stretched polyamide film can be used not only as a single-layer film but also as a multilayer film. Examples of the multilayer film include a multilayer film laminated by a coextrusion method or a lamination method. Examples of the layer to be laminated include a sealant layer composed of polyolefins and a gas barrier layer composed of a saponified product of a copolymer of ethylene and vinyl acetate.

The thickness of the stretched film of the present invention is preferably from 2 to 50 μm, more preferably from 3 to 40 μm. In the case of a single-layer film, more preferably 5-35 μm
m. In the case of a laminated film, the thickness of the layer of the stretched film composed of the polyamide resin composition is preferably 2
To 30 μm, and more preferably 3 to 25 μm.

The specific haze value of the stretched film of the present invention is represented by the following formula, and is preferably 1.0 or more. Specific haze value = haze value (%) / film thickness (μm) When the specific haze value is less than 1.0, opacity is insufficient. The specific haze value is more preferably 1.5 or more, and most preferably 1.7 or more. The specific haze value is an index of translucency or opacity of a material. As the value increases, the content becomes less visible.

[0018]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. The raw materials used are as follows. (1) 6 nylon (a): 6 nylon (Novamid 1030 manufactured by Mitsubishi Engineering-Plastics Corporation)
J, relative viscosity 4.5) (2) 6/66 copolymer nylon (a): 6/66 copolymer nylon (Mitsubishi Engineering Plastics Co., Ltd.)
Made, Novamid 2030J, nylon 6 units 85% by weight
/ Nylon 66 unit 15% by weight, relative viscosity 4.5)

(3) 6/66 copolymer nylon (b): 6
/ 66 copolymer nylon (Novmid 2320J, manufactured by Mitsubishi Engineering-Plastics Corporation, nylon 6 units 95% by weight / nylon 66 units 5% by weight, relative viscosity 3.5) (4) 6/66 copolymer nylon (c) : 6/66 copolymer nylon (Mitsubishi Engineering Plastics Co., Ltd.)
Made, Novamid 2430J, nylon 6 units 80% by weight
/ Nylon 66 unit 20% by weight, relative viscosity 4.5)

(5) Zeolite (a): Amorphous zeolite (manufactured by Mizusawa Chemical Industry Co., Ltd., Shilton AMT-50, oil absorption 26 ml / 100 g) (6) Zeolite (b): Amorphous zeolite (Mizusawa Chemical Industries ( Co., Ltd., Shilton AMT-08, oil absorption 68 ml
(7) Zeolite (c): amorphous zeolite (manufactured by Mizusawa Chemical Industry Co., Ltd., Shilton AMT-25, oil absorption 45 ml)
(8) Zeolite (d): crystalline zeolite (manufactured by Mizusawa Chemical Industry Co., Ltd., Shilton AMT-08, oil absorption 75 ml)
/ 9Og) (9) Silica: silica (Mizukasil P-603, manufactured by Mizusawa Chemical Industry Co., Ltd., lubrication amount 115ml / 100g)

(10) Measurement of relative viscosity of polyamide: J
It was measured according to IS K6810 at a concentration of 1% in 98% sulfuric acid at a temperature of 25 ° C. (11) Haze value: Measured using a fully automatic haze meter MODE-TC-H3DPK manufactured by Tokyo Denshoku Co., Ltd. (12) Measurement of oil absorption: Oil was dripped from a burette onto a powder sample in accordance with JIS K-5101.
When kneading with a spatula, a value was obtained by converting the amount of oil to the minimum required amount of oil that allowed the sample to be spirally wound with the spatula per 100 g of the sample.

Example 1 32 parts by weight of 6 nylon (a) and 2 parts by weight of zeolite (a) were blended and kneaded at a resin temperature of 260 ° C. using a twin screw extruder to form pellets.
The obtained pellets were vacuum dried at 120 ° C. for 10 hours to obtain a master batch. After blending 34 parts by weight of the obtained master batch and 68 parts by weight of 6 nylon (a), a T-die film forming machine comprising an extruder having a diameter of 40 mmφ forms a 150 μm thick film at a resin temperature of 250 ° C. did.
The haze value of the obtained film was 5.3%. This film was heated to 80 ° C. in a stretching apparatus (a film stretcher manufactured by TM Long Co.), and then simultaneously stretched 3 × 3 times at different stretching speeds to obtain a stretched film. The obtained stretched film was heat-set in an oven at 180 ° C. for 1 minute. When the thickness and haze of the film thus obtained were measured, the thickness was 15 μm, the haze value was 45.1, and the specific haze value was 3.0.

Comparative Example 1 6.7 parts by weight of 6 nylon (a) and 0.4 part by weight of zeolite (a) were blended and kneaded at a resin temperature of 260 ° C. using a twin screw extruder to form pellets. did. The obtained pellets were vacuum dried at 120 ° C. for 10 hours to obtain a master batch. After blending 7.1 parts by weight of the obtained master batch with 93.3 parts by weight of 6 nylon (a), a stretched film was obtained in the same manner as in Example 1 using a T-die type film forming machine and a stretching apparatus. Table 1 shows the evaluation results. [Comparative Example 2] 100 parts by weight of 6 nylon (a) and 6 parts by weight of zeolite (a) were blended and kneaded at a resin temperature of 260 ° C using a twin-screw extruder to form pellets. After vacuum drying the obtained pellets at 120 ° C. for 10 hours, a stretched film was obtained in the same manner as in Example 1 using a T-die type film forming machine and a stretching apparatus, but a stretch break occurred. Table 1 shows the evaluation results.

[0024]

[Table 1]

Example 2 A stretched film was prepared in the same manner as in Example 1 except that 6/66 copolymer nylon (a) was used instead of 6 nylon (a). Table 2 shows the evaluation results. Comparative Example 3 In Comparative Example 1, except that 6/66 copolymer nylon (a) was used instead of 6 nylon (a),
A stretched film was prepared in the same manner as in Comparative Example 1. Table 2 shows the evaluation results. Comparative Example 4 In Comparative Example 2, except that 6/66 copolymer nylon (a) was used instead of 6 nylon (a),
An attempt was made to obtain a stretched film in the same manner as in Comparative Example 2, but a stretch break occurred. Table 2 shows the evaluation results.

[0026]

[Table 2]

Example 3 16 parts by weight of 6/66 copolymerized nylon (b) and 1 part by weight of zeolite (a) were blended and kneaded at a resin temperature of 260 ° C. using a twin screw extruder to form pellets. did. The obtained pellet is heated at 120 ° C. for 1 hour.
It was vacuum dried for 0 hour to obtain a master batch. After blending 17 parts by weight of the obtained masterbatch and 84 parts by weight of 6/66 copolymer nylon (b), the T
A stretched film was obtained using a die-type film forming machine and a stretching apparatus. Table 3 shows the evaluation results. [Example 4] 48 parts by weight of 6/66 copolymerized nylon (b) and 3 parts by weight of zeolite (a) were blended and kneaded at a resin temperature of 260 ° C using a twin-screw extruder to prepare pellets.
The obtained pellets were vacuum dried at 120 ° C. for 10 hours to obtain a master batch. After blending 51 parts by weight of the obtained master batch and 52 parts by weight of 6/66 copolymerized nylon (b), a stretched film was obtained in the same manner as in Example 1 using a T-die type film forming machine and a stretching apparatus. Table 3 shows the evaluation results.

Example 5 16 parts by weight of 6 nylon (a) and 1 part by weight of zeolite (a) were blended and kneaded at a resin temperature of 260 ° C. using a twin-screw extruder to prepare pellets.
The obtained pellets were vacuum dried at 120 ° C. for 10 hours to obtain a master batch. After blending 17 parts by weight of the obtained master batch and 84 parts by weight of 6/66 copolymer nylon (c), a stretched film was obtained in the same manner as in Example 1 using a T-die type film forming machine and a stretching apparatus. Table 3 shows the evaluation results. Example 6 64 parts by weight of 6 nylon (a) and 4 parts by weight of zeolite (a) were blended and kneaded at a resin temperature of 260 ° C. using a twin-screw extruder to prepare pellets. The obtained pellets were vacuum dried at 120 ° C. for 10 hours to obtain a master batch. 68 parts by weight of the obtained master batch and 6/6
After blending 36 parts by weight of 6-copolymer nylon (c), a stretched film was obtained in the same manner as in Example 1 using a T-die type film forming machine and a stretching apparatus. Table 3 shows the evaluation results.

[0029]

[Table 3]

Example 7 In Example 1, except that zeolite (b) was used instead of zeolite (a),
A stretched film was prepared in the same manner as in Example 1. Table 4 shows the evaluation results. Example 8 72 parts by weight of nylon 6 (a) and 4.5 parts by weight of zeolite (a) were blended and kneaded at a resin temperature of 260 ° C. using a twin-screw extruder to prepare pellets. The obtained pellets were vacuum dried at 120 ° C. for 10 hours to obtain a master batch. After blending 76.5 parts by weight of the obtained master batch and 28 parts by weight of 6 nylon (a), Example 1 was blended.
Similarly to the above, a stretched film was obtained with a T-die type film forming machine and a stretching apparatus. Table 4 shows the evaluation results.

Example 9 In Example 1, except that zeolite (c) was used instead of zeolite (a),
A stretched film was prepared in the same manner as in Example 1. Table 4 shows the evaluation results. Comparative Example 5 A stretched film was prepared in the same manner as in Example 1 except that silica was used instead of zeolite (a). Table 4 shows the evaluation results. Comparative Example 6 A stretched film was obtained in the same manner as in Example 1, except that zeolite (d) was used instead of zeolite (a). Table 4 shows the evaluation results.

[0032]

[Table 4]

[0033]

Industrial Applicability The polyamide resin composition for a stretched film of the present invention has excellent mechanical strength, heat resistance, chemical resistance, etc., low transparency and excellent concealment properties, and has excellent stretchability, particularly biaxial stretching. Two excellent. Moreover, the stretched film made of the polyamide resin composition is excellent in concealing the contents to be packaged, can withstand heat treatment such as retort, and is useful in various uses such as food and medical use.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 7:00

Claims (8)

[Claims] 1. A polyamide resin composition containing 0.5 to 5 parts by weight of amorphous zeolite with respect to 100 parts by weight of a polyamide resin.
The polyamide-forming unit composed of caprolactam (6 units of nylon) is 60 to 100% by weight, and the polyamide-forming unit composed of adipic acid and hexamethylenediamine (66 units of nylon) is 0 to 40% by weight. A polyamide resin composition for a stretched film. 2. The polyamide resin is a polyamide resin obtained by polymerizing ε-caprolactam, a copolymerized polyamide resin obtained by polymerizing ε-caprolactam, adipic acid and hexamethylenediamine, or a blend thereof. The polyamide resin composition for a stretched film according to claim 1, wherein 3. The relative viscosity of the polyamide resin is 1.5 to 6.0 as measured at a concentration of 1% in 98% sulfuric acid and a temperature of 25 ° C.
The polyamide resin composition for a stretched film according to claim 1 or 2, wherein 4. An amorphous zeolite having an oil absorption of JIS
The polyamide resin composition for a stretched film according to any one of claims 1 to 3, wherein the amount is 1 to 70 ml / 100 g as measured by the K-5101 method. 5. A stretched film comprising the polyamide resin composition for a stretched film according to claim 1. 6. The stretched film according to claim 5, wherein the stretched film is a biaxially stretched film. 7. The stretched film according to claim 5, wherein the thickness of the stretched film is 2 to 50 μm. 8. The stretched film according to claim 5, wherein the specific haze value of the stretched film is 1.0 or more. Specific haze value = haze value (%) / film thickness (μm)