JPS62106926A - Polyamide packaging material - Google Patents

Abstract

PURPOSE:To obtain a packaging material excellent in gas barrier property, strength and heat resistance, by using a polyamide mainly consisting of repeating tetramethylene adipamide units or repeating tetramethylene isophthalamide units as a component of the material. CONSTITUTION:A packaging material containing a polyamide mainly consisting of repeating tetramethylene adipamide units and/or repeating tetramethylene isophthalamide units as a component thereof. The polyamide used has a content of tetremethylene adipamide units and/or tetramethylene isophthalamide units of above 50%, preferably, above 80% of the total repeating units. When this content is below 50%, the gas barrier property is not sufficient. When a polyamide containing both of tetramethylene adipamide units and tetramethylene isophthalamide units is used, the ratio between these two kinds of units is preferably 90:10-10:90 on account of transparency and heat resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a polyamide packaging material, and more particularly to a polyamide packaging material having excellent gas barrier properties, strength, and heat resistance.

<Prior Art> Packaging materials, especially food packaging materials, require materials with good gas barrier properties in order to extend the shelf life of foods and keep them fresh.

For example, if the food to be packaged contains oil, deterioration progresses due to oxygen permeation, so the packaging material should be a material with excellent oxygen barrier properties. In order to maintain coolness, materials with excellent carbon dioxide gas barrier properties are used. Various materials have been developed to meet these demands, and examples of such materials include poly(t'-nylidene chloride), ethylene-vinyl alcohol copolymer, polyamide, and polyethylene terephthalate. It will be done. Films of these polymers have other requirements besides gas barrier properties (e.g. strength,
In order to satisfy moisture permeability and weather resistance '4), further practical value can be given by so-called multilayering, such as laminating with other types of polymer films or coating the surface with other types of materials. Among these materials, polyamide has excellent processability, heat resistance, and strength, and is widely used as a packaging material.

However, nylon 6 and nylon 66 do not necessarily have sufficient gas barrier properties, and there is a desire to develop materials with even better gas barrier properties.

<Objective of the Invention> An object of the present invention is to provide a polyamide packaging material with excellent gas barrier properties.

<Structure of the Invention> The present invention is a packaging material containing a polyamide whose main repeating units are tetramethylene azide-2ψmid units and/or tetramethylene isophthalamide units.

In the present invention, when using a polyamide containing tetramethyleneazihalamide units and tetramethylene isophthalamide units, the ratio of the respective amide units is not particularly specified, but considering transparency and heat resistance, the ratio is 90%.
:10 to 10:90 is desirable. If the proportion of tetramethylene azinophthalamide units exceeds 90, the crystallization rate of the polyamide is extremely fast (・), so that the resulting molded product tends to become cloudy. When it exceeds 90, heat resistance tends to decrease.

In the present invention, "main J" refers to a proportion of more than 50%. Therefore, it can contain less than 50 other amide units, and copolymer components constituting such amide units include tetramethylenediamine, adipic acid, isophthalic acid, etc. In addition to acids, there are other diamines, dicarboxylic acids, aminocarboxylic acids, and lactams, and specific VCs include aromatic dicarboxylic acids,
For example, terephthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, sodium-sulfoisophthalic acid, dibromoterephthal powder, etc.; alicyclic dicarboxylic acids, e.g. , decalin dicarboxylic acid, etc.; aliphatic dicarboxylic acids, such as )I-phosphoric acid, sepatic acid, etc.; aliphatic diamines, such as ethylene diamine, trimethylene diamine, hexamethylene diamine, etc.; aromatic diamines, such as phenylene diamine,
xylylene diamine, 3,6-diamitacridine, N
-methyl-p-phenylenediamine, N5N-dimethyl-p-phenylenediamine, tolylenediamine, etc.; aliphatic diamines, such as 1,2-diaminocyclobutane; aliphatic aminocarboxylic acids, such as glycine, alanine, valine Aromatic aminocarboxylic acids, such as phenylalanine, amine benzoate, etc.; Lipid aminocarboxylic acids, such as aminochlorhexanecarboxylic acid; Lactams; such as β-propiolactam, T
-butyrolactam, ε-caprolactam, etc. are exemplified.

In the polyamide used in the present invention, it is necessary that the number of tetramethylene adipamide units and/or tetramethylene isophthalamide units exceeds 50% of the repeating units, and preferably 80 units or more. If it is less than 50 yen, the gas barrier property is not sufficient.

The relative viscosity of the polyamide used in the present invention (measured when dissolved in a 96°C sulfurizing solvent at 20°C) is preferably 2°0 or more in view of the strength required as a packaging material.

Examples of the polyamide packaging material of the present invention include a film obtained by a forming method involving stretching, and containers such as bottles and pots. It also includes a sheet or a tray-shaped sheet with a vacuum or pressure bottom. Also, unstretched 4
It may be a container made by deep drawing an 11-layer sheet, or a container made by forming a bottomed Vibrator and stretching it.

Such polyamides can be produced by conventionally known methods for producing polyamides. For example, it can be produced by reacting tetramethylene diamine with adipic acid and/or isophthalic acid in a methanol solvent to form a salt, and further polycondensing the sown reaction product. At that time, various degenerated gold catalysts, stabilizers, etc. can be used.

Further, other additives such as colorants, optical brighteners, oxidation stabilizers, ultraviolet absorption agents, antistatic agents, flame release agents, etc. may be used as necessary.

Further, the film or sheet can be manufactured by a method conventionally known as a film or sheet molding method. For example, after drying at a temperature of 80°C or higher for 30 minutes or more, it is melt-extruded using an extruder equipped with a T-die or I-die and then rapidly cooled to form an unstretched film or sheet, or it is further uniaxially or biaxially stretched. , oriented sheets or films can be produced.

<Effects of the Invention> The polyamide packaging material of the present invention has excellent gas barrier properties. For example, the carbon dioxide gas permeability coefficient is 115 to 1/10 that of nylon 6, making it extremely useful especially for packaging items that require gas barrier properties.

<Example> Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, the method for measuring the characteristics used in the examples is shown below.

0 relative viscosity (ηrel) 0.0 in 96 thiosulfuric acid. Measured at 20℃ as IM characteristic 0 Intrinsic viscosity ([da]) Measured at 25℃ using m-cresol solventQ Oxygen gas permeability coefficient (Po□) and carbon dioxide gas permeability coefficient (
pco□) o2/co, =' 80/20 (vol.
Measurement of oxygen gas permeation filtration and carbon dioxide gas permeation risk at 30°C using a mixed gas of
A polyamide (hereinafter referred to as nylon 46) having a polyamide of 3.5 was obtained. Nylon 46 was dried at 100℃ using a vacuum dryer.
After drying for 4 hours, a film with a thickness of about 100 μm was produced using a 30 mm diameter extruder at a cylinder temperature of 300° C. and a roll temperature of about 20° C.

This film had a milky appearance.

For comparison, films of nylon 6 ([η)-1,2) and nylon 66 ([η)=1.3) were produced in the same manner.

Table 1 shows the results of gas barrier properties measured using these films.

Table 1 The polyamide of the present invention has excellent gas barrier properties.

Examples 2 to 5 Polyamides were obtained by polycondensation of tetramethylene diamine, adipic acid, and isophthalic acid.

Table 2 shows the ηrel, appearance and gas barrier properties of this polyamide.

Hand U and Lord 11 Original Book October 22, 1986 Special R.J. Te Ch.'White'dono 1, Indication of Case Patent Application No. 1983-244110 @2, Name of Invention Polyamide Packaging Material Contact Information (506) 4481 6. Contents of amendment (1) Specification, page 6, line 3, [0, IJ)'1.
Correction to O.J.

(2) Same, 8th shell, 5th line, correct [0, 1j to [1, 0J].

that's all

Claims (1)

[Scope of Claims] A packaging material containing, as a constituent component, a polyamide whose main repeating units are tetramethylene adipamide units and/or tetramethylene isophthalamide units.