KR0178050B1 - Polyamide resin composition for film - Google Patents

Abstract

In the present invention, the inorganic particle having an average particle diameter of 0.1 to 6 µm and a surface area of 300 m ² / g or more is represented by 0.03 to 0.12% by weight based on 100% by weight of a copolymer containing nylon 6 as a main component, represented by the following structural formulas (I) and (II) Nonionic ester-based surfactant 0.01 ~ mixture of polyoxyethylene sorbitan fatty acid ester consisting of 6 rings and 5 rings and the glycerin mono fatty acid ester of formula (III) in a weight ratio of 30 to 50/30 to 50/0 to 40 0.5% by weight, phosphate ester salt of formula (IV) or 0.001 to 5% by weight phosphate ester of formula (V) is provided to provide a polyamide resin composition for film production, the composition of the present invention The film produced by this has the advantage that it can be manufactured to be excellent in surface properties, transparency, antistatic property and suitable for the needs of the consumer.

(Wherein, R is an alkyl group having 5 to 20 carbon atoms, n ₁ , n ₂ , n ₃ are each an integer of 5 to 20.)

(Wherein, R is an alkyl group having 5 to 20 carbon atoms, n ₁ , n ₂ , n ₃ are each an integer of 5 to 20.)

(Wherein R is an alkyl group having 2 to 20 carbon atoms)

(Wherein R is an alkyl group having 2 to 20 carbon atoms, n ₁ and n ₂ are each an integer of ₂ to 20, and M ⁺ is Na ⁺ or K ⁺ )

(Wherein R is an alkyl group having 2 to 20 carbon atoms, n ₁ and n ₂ are each an integer of ₂ to 20).

Description

Polyamide Resin Composition for Film Production

The present invention relates to a polyamide resin composition for film production, and more particularly, to a polyamide resin composition for film production, which can be processed into a film having excellent surface properties, transparency, antistatic properties and suitable for the physical properties of polyamide film users. It is about.

Polyamide film has excellent transparency, pinhole resistance, gas barrier property, heat resistance, oil resistance, etc., and is widely used in food packaging fields such as meat processed food or retort food and other industrial product packaging fields.

The polyamide film has a biaxially oriented film forming method, molding conditions, and the like depending on the range of use, such as cold resistance, heat resistance, oil resistance, water absorption, impact resistance, gas barrier property, printability, lamination resistance to other films, and the user's requirements. The polyamide resin should be produced in different composition. However, it is extremely difficult to produce and control the physical properties of the polyamide film in order to meet these various needs, and there has been a demand for improvement.

Accordingly, it is an object of the present invention to provide a polyamide resin composition for film production that can be processed into a film having excellent surface properties, transparency, antistatic properties and suitable for various demands of polyamide film users.

That is, in the present invention, 0.03 to 0.12% by weight of inorganic fine particles having an average particle diameter of 0.1 to 6 µm and a surface area of 300 m ² / g or more based on 100% by weight of a copolymer containing nylon 6 as a main component, the following structural formulas (I) and (II Nonionic ester system which mixed polyoxyethylene sorbitan fatty acid ester which consists of 6 rings and 5 rings represented by the following), and the glycerin mono fatty acid ester of following formula (III) in the weight ratio of 30-50 / 30-50 / 0-40. It is providing the polyamide resin composition for film manufacture which contains 0.01-0.5 weight% of surfactant, phosphate ester salt of following formula (IV), or 0.001-5 weight% of phosphate ester of following formula (V).

(Wherein R is an alkyl group having 5 to 20 carbon atoms,

n ₁ , n ₂ , and n ₃ are each an integer of 5 to 20.)

(Wherein R is an alkyl group having 5 to 20 carbon atoms,

n ₁ , n ₂ , and n ₃ are each an integer of 5 to 20.)

(Wherein R is an alkyl group having 2 to 20 carbon atoms)

(Wherein R is an alkyl group having 2 to 20 carbon atoms,

n ₁ and n ₂ are each an integer from ₂ to 20

M ⁺ is Na ⁺ or K ⁺ )

(Wherein R is an alkyl group having 2 to 20 carbon atoms,

n ₁ and n ₂ are each an integer of ₂ to 20.)

Hereinafter, the present invention will be described in more detail.

As the polyamide resin used in the present invention, a copolymer containing nylon 6 as a main component is used. Copolymers based on nylon 6 contain 95-99.9% by weight of ε-caprolactam, hexamethylenediamine, 2-methylpentamethylenediamine, metaparaxylenediamine, adipic acid and 12-aminododecanoic acid or lauryllactam And polyamide copolymers obtained by melt-polymerizing 0.1 to 5% by weight of a mixture of these compounds.

The introduction of the monomer into the main chain in the nylon 6 is to be able to provide a film suitable for the physical properties of the user without compromising the inherent physical properties of the nylon 6 film. 2-methylpentamethylenediamine has a structure in which the main chain is made of odd carbon and has a methyl group as a branch, thereby preventing crystallization of the main chain of nylon 6 and improving transparency. In addition, since metaparaxylenediamine has an aromatic, it can maintain stability at high temperature, and 12-aminododecanoic acid has a long alkyl group, which is highly moisture resistant and has the strength of maintaining the properties of the film even at low temperatures. In addition, polyamide copolymers generally have a wider processing temperature range than nylon 6 homopolymers.

In the copolymer based on nylon 6 used as a polyamide resin in the present invention, when the mixing ratio of the monomers is less than 0.1% by weight can not improve the desired physical properties, on the contrary if it exceeds 5% by weight It is not preferable because the manufacturing cost is increased.

In the preparation of the polyamide polymer of the present invention, inorganic fine particles are added as a blocking agent of the polyamide film, and the inorganic fine particles have an average particle diameter of 0.1 to 6 µm and a surface area of 300 m ² / g, based on 0.03 to 0.12% by weight of the polymer. It is used in the amount of addition. The addition of the inorganic fine particles may be added at any stage of the polymerization, in the middle stage, or at the end of the polymerization, but it is advantageous to add the inorganic fine particles in the initial stage of polymerization for even dispersion in the polymer.

As the inorganic fine particles in the present invention, silica, kaolin, talc, calcium carbonate, and other aluminosilicates composed of a mixture of compounds of oxides such as Si, Al, Mg, and Na may be used. In the case of addition of the inorganic fine particles, it is important to select an inorganic additive having a similar refractive index to the polyamide resin used for the transparency of the film.

In the present invention, when the content of the inorganic fine particles is less than 0.03% by weight, the role as an antiblocking agent is insufficient, and when the content of the inorganic fine particles exceeds 0.12% by weight, the glossiness and transparency of the film are reduced, and the gap between the inorganic additive and the polyamide is used. Mechanical strength and gas barrier properties are reduced.

In the present invention, in order to achieve even mixing of the polyamide chips of aliphatic amides and alkyl ester salts known as inorganic fine particles and known film additives and to improve dispersibility during film processing, the six rings and 5 of formulas (I) and (II) Nonionic ester-based surfactants in which polyoxyethylene sorbitan fatty acid esters of a ring and glycerin mono fatty acid esters of formula (III) are mixed at a weight ratio of 30 to 50/30 to 50/0 to 40, 0.01 to 0.5% by weight relative to the used.

If the nonionic ester surfactant is added in an amount less than 0.01% by weight, the transparency of the polyamide film is lowered. If the content of these nonionic ester surfactants exceeds 0.5% by weight relative to the polyamide resin, the nonionic surfactant is used. Is present in the portion other than the interface between the polyamide film and the inorganic fine particles, and the inorganic fine particles are agglomerated to each other, resulting in fish-eye on the surface of the film and deteriorating slippage property.

On the other hand, the polyamide film has a disadvantage in that workability is poor at the time of film forming or post-processing of the film due to static electricity because the volume specific resistance is large, like other plastic films. In the present invention, 0.001 to 5% by weight of the phosphate salt of formula (IV) or phosphate ester of formula (V) was added as an antistatic agent in order to improve such disadvantages. If the antistatic agent is less than 0.001% by weight based on the total resin, the antistatic property is insufficient, and when the antistatic agent exceeds 5% by weight, the appearance of the film is damaged and the strength of the film is lowered.

In the present invention, the aliphatic ester surfactant and the phosphate antistatic agent may be added to the polyamide resin in the polyamide polymerization step or through dry blending with a polyamide chip.

In addition, the aliphatic amide compounds, stearates, and the like, which are used as known lubricants, may be used in combination within the range not impairing the basic physical properties of the polyamide resin composition of the present invention.

In the production of the polyamide resin composition for film production of the present invention, the polymerization process of the polyamide copolymer is as follows.

1) First, an aqueous solution of a salt consisting of a mixture of adipic acid and aliphatic diamine is introduced into the reactor. At this time, a mixture of hexamethylenediamine, 2-methylpentamethylenediamine, and metaparaxylenediamine is used as the diamine. Depending on the properties required, 12-aminododecanoic acid or lauryllactam can be added in admixture with the monomers.

2) A proportion of caprolactam is added to the reactor.

3) Pressurize for reaction and maintain constant pressure while releasing water while heating the mixture.

4) The polymerization degree is determined by setting the temperature inside the reactor and the reduced pressure conditions at a level having a relative viscosity of 3.3 to 3.8 and a molecular weight distribution ranging from 2 to 4.

5) The reactor is evacuated to atmospheric pressure and maintained at a constant viscosity.

6) The discharged polymer is made into chips.

7) In order to manage the hot water extract of the polymer to be 0.5% or less, unreacted materials are extracted at the maximum bath ratio and dried to prepare a chip for manufacturing the final polyamide film.

The chip manufactured by the above-described method can be molded into a film by a generally known T-die method or inflation method. For example, the chips are fed into an extruder through a hopper, heated to melt, extruded from an extrusion die, and then cooled and solidified to produce an unstretched fabric, which is then simultaneously co-ordinated in the advancing direction (MD) and width direction (TD) of the film. Alternatively, the film may be prepared by heat-setting after successive stretching.

The stretching method after shaping | molding of a polyamide film can be roughly divided into the tubla method and the tenta method. Although the tenta method is an easy method for mass production of films, it is difficult to avoid a lot of investment in processing equipment, and it is difficult to set the processing conditions for stretching the film while maintaining the balance in the width direction and the length direction. In contrast, the tubular method stretches the width direction and the length direction at the same time by the pressure of the fluid introduced into the film, thereby bringing the draw ratios in the width direction and the length direction together. Can be obtained. In addition, the tubular method has the advantages of low facility investment cost, installation in a narrow space, and providing a variety of high quality films.

The polyamide resin composition for producing a film of the present invention may be processed into a film alone or may be combined with ethylene vinyl alcohol copolymer (EVOH) having excellent gas barrier properties in order to further improve gas barrier properties of the final film according to a known method. It can be molded by extrusion or made into a film by a method of coating polyvinylidene chloride (PVDC) having good gas barrier properties.

Laminated film produced by laminating with biaxially stretched polyamide film or other film prepared from the polyamide resin composition of the present invention is excellent in surface properties, transparency, slip properties and antistatic properties, and also suitable for the needs of users The physical properties such as transparency, heat resistance, moisture resistance, low temperature stability and the like are improved.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are only for describing specific embodiments of the present invention, and the present invention is not limited to the following Examples. The physical property evaluation method of the film used in the present Example is as follows.

[Assessment Methods]

1. Heat transition temperature: Melting temperature, crystallization temperature, low temperature crystallization temperature, glass transition temperature, etc. were measured using a thermal analyzer (Perkin-Elmer's DSC-7) with the temperature rise and fall rates of 20 ℃ / min. Are the maximum points of the peaks, and the glass transition temperature is set at the position of 1/2 of the heat capacity.

2. Hot water extract: Polyamide resin was measured by weight loss after extraction with hot water at 100 ° C. for 12 hours using an extractor (Soxhlet).

3. Relative Viscosity: The polyamide resin was dissolved in concentrated sulfuric acid (98%) at a concentration of 0.25 g / dl, and then measured using a Cannon-Fenske viscometer in a 25 ° C thermostat.

Relative Viscosity = Falling seconds of solution (sec) / Falling seconds of pure sulfuric acid (sec)

4. Molecular weight distribution: Obtained by GPC analysis using 150-CALC model of Water (Water), the solvent and fluid phase was used for the metacresol, the measurement temperature was carried out at 100 ℃.

Molecular weight distribution = weight average molecular weight / number average molecular weight

5. Transparency: According to ASTM D-1003, haze was measured using a haze meter manufactured by Nippon Electric Corporation.

6. Surface glossiness: Surface glossiness was measured according to ASTM D-2457 with an incident angle of 20 °.

7. Friction Coefficient: According to ASTM D-1894, the static friction coefficient was measured using a friction coefficient measuring instrument at 20 ° C and 65% relative humidity.

8. Number of gels: A film of 20 cm × 20 cm was accurately observed with the naked eye, and the number of gels of 100 µm or more was counted.

9. Tensile strength: in accordance with ASTM D-882 was measured using a universal tensile tester at 20 ℃, 65% relative humidity atmosphere.

10. Heat shrinkage rate: After dipping a film of 20cm × 20cm in hot water at 100 ℃ 30 minutes, the length change rate in the longitudinal direction and the width direction was measured.

11. Hygroscopicity: Tensile strength after soaking a 1 cm × 15 cm film in water at 25 ° C. for 24 hours was measured and expressed as a reduction rate before and after treatment.

12. Surface specific resistance: Surface specific resistance was measured using Takedai Co., Ltd. High Resistance Insulation Tester at 20 ℃ and 33 ℃ relative humidity.

Example 1

Silica dispersion was prepared by adding silica (Fuji Silysia Co., Ltd., average particle diameter: 1.4 μm, surface area: 300 m ² / g) into an aqueous solution of 50 wt% of ε-caprolactam and stirring for at least 2 hours to achieve a uniform dispersion state using a homomixer. do. To 100% by weight of the total polyamide copolymer resin, hexamethylenediamine and artisan salt were placed in a 2% by weight reactor, and ε-caprolactam and a prepared silica dispersion were added to the composition ratio shown in Table 1. This 0.07% by weight polyamide copolymer was polymerized to prepare a chip. Polyoxyethylene (20) sorbitan monostearate (manufactured by Nippon Oil Industries, Ltd.) having the structures of Formulas (I) and (II) to 100% by weight of the prepared polyamide copolymer, A mixture of 0.06% by weight of a nonionic ester-based surfactant and 0.05% by weight of dilauryl phosphate calcined salt having a glycerin monostyrene (manufactured by Yuji Co., Ltd.) having a structure in a ratio of 40/40/20 is evenly mixed with a dry mixer under a nitrogen atmosphere. To prepare a polyamide resin composition for film production.

Subsequently, an extruder was extruded downwardly at 255 ° C. using an annular die having a diameter of 400 mm to quench with 15 ° C. water to obtain an unstretched film fabric. Pressurized gas was fed into the tube between two sets of nip rollers with different speeds and simultaneously biaxially stretched with MD / TD = 3 / 3.2 times to produce a film diameter of 700 mmφ and a thickness of 15 µm at a film surface temperature of 70 ° C. Phosphorus biaxially oriented film was prepared. After that, the stretched film is transferred to the heat setting tower through the guide roller, and then the low pressure gas is fed into the film, and the film surface is passed through the heat setting tower at a speed of 60 m / min continuously in the tube state. After the first heat setting and folding for 8 seconds to fold the temperature to 180 ° C, the film is separated into two sheets, and each film is contacted with the secondary heat treatment roller, and the second heat setting is performed at 90 ° C for 3 seconds, and then wound up in a winder, and the final poly An amide film was prepared. The negative of the obtained polyamide film was evaluated and the results are shown in Table 3 below.

EXAMPLES 2-6

Except for changing the process conditions according to the composition of the polyamide resin composition and the composition of the polyamide resin composition in Example 1 as shown in Table 1 and Table 2 in the same conditions and methods as in Example 1 To prepare, and evaluated the physical properties thereof are shown in Table 3 below.

[Comparative Examples 1-7]

The same conditions and methods as in Example 1 were changed except for changing the process conditions according to the composition of the polyamide resin composition and the composition of the polyamide resin composition in Example 1, as shown in Tables 1 and 2 below. A polyamide film was prepared, and the physical properties thereof were evaluated and shown in Table 3 below.

Claims (3)

6 rings represented by the following structural formulas (I) and (II) with respect to 100% by weight of nylon 6-based copolymer, and inorganic particles having an average particle diameter of 0.1 to 6 µm and a surface area of 300 m ² / g or more. 0.01 to 0.5% by weight of a nonionic ester surfactant, in which a polycyclic ethylene sorbitan fatty acid ester composed of five rings and a glycerin mono fatty acid ester of the following formula (III) are mixed at a weight ratio of 30 to 50/30 to 50/0 to 40 Including the phosphate ester salt of the following formula (IV) or 0.001-5 weight% of phosphate ester of the following formula (V), the relative viscosity is 3.3-3.8, the molecular weight distribution is 2-4 range, and brine extract is 0.5% or less Polyamide resin composition for film production. (Wherein, R is an alkyl group having 5 to 20 carbon atoms, n ₁ , n ₂ , n ₃ are each an integer of 5 to 20.) (Wherein, R is an alkyl group having 5 to 20 carbon atoms, n ₁ , n ₂ , n ₃ are each an integer of 5 to 20.) (Wherein R is an alkyl group having 2 to 20 carbon atoms) (Wherein R is an alkyl group having 2 to 20 carbon atoms, n ₁ and n ₂ are each an integer of ₂ to 20, and M ⁺ is Na ⁺ or K ⁺ ) (Wherein R is an alkyl group having 2 to 20 carbon atoms, n ₁ and n ₂ are each an integer of ₂ to 20). The copolymer of claim 1, wherein the copolymer based on nylon 6 is a) 95 to 99.9 wt% of caprolactam and b) hexamethylenediamine, 2-methylpentamethylenediamine, metaparaxylenediamine, adipic acid, 12- A polyamide resin composition for film production, characterized in that it is prepared by melt-polymerizing 0.01 to 5% by weight of at least one mixture selected from the group consisting of aminododecanoic acid or lauryl lactam. The polyamide resin composition for film production according to claim 1, wherein the inorganic fine particles are selected from the group consisting of silica, kaolin, talc, calcium carbonate, alumina or a mixture of two or more thereof.