JP2000290500A - Polyamide molding - Google Patents

Abstract

(57) [Summary] [PROBLEMS] The present invention provides transparency required for packaging materials,
An object of the present invention is to provide a polyamide molded article having excellent gas barrier properties and mechanical performance. SOLUTION: A diamine containing 70 mol% or less of meta-xylylenediamine in a diamine component, and an α, ω-linear aliphatic carboxylic acid having 4 to 20 carbon atoms in a dicarboxylic acid component are contained in 7 parts.
A resin composition (C) obtained by blending 0.1 to 10 parts by weight of a layered silicate (B) with respect to 100 parts by weight of a polyamide resin A) obtained by polycondensation with a dicarboxylic acid containing 0 mol% or more was molded. A polyamide molded product, characterized in that a layered silicate is finely dispersed in a polyamide resin by melt-kneading.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide molded article excellent in transparency, gas barrier properties and mechanical performance as a packaging material for foods, beverages, medicines, electronic parts and the like.

[0002]

2. Description of the Related Art A polyamide obtained from a polycondensation reaction between xylylenediamine and an aliphatic dicarboxylic acid, for example, a polyamide MXD6 (hereinafter sometimes referred to as "MX nylon") obtained from meta-xylylenediamine and adipic acid.
Because of its low permeability to gaseous substances such as oxygen and carbon dioxide, it is used as a film or bottle as a gas barrier material. However, in recent years, the necessity of gas barrier packaging for preserving foods and beverages for a long period of time without deteriorating freshness has been further increased, and further improvement in gas barrier properties is required.

One of the methods for improving the gas barrier properties of a polyamide resin is to add a layered silicate to the polyamide resin. In Japanese Patent Publication No. 58-35211 and JP-A-2-105856, etc., after the layered silicate is swollen in advance, the ε-
A method is disclosed in which a layered silicate is uniformly dispersed in polyamide-6 by mixing and polymerizing with caprolactam. Although the gas barrier property of the polyamide-6 is improved by this method, the melt viscosity after the addition of the layered silicate increases, so that there is a concern that it is difficult to extract the polymer from the polymerization can.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a polyamide molded article excellent in transparency, gas barrier property and mechanical performance required as a packaging material by finely dispersing a layered silicate in a polyamide resin. It is something to offer.

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, the above-mentioned problems can be solved by melt-kneading a polyamide resin having a specific structure and a layered silicate. This led to the completion of the present invention.

That is, the present invention relates to a diamine containing 70% by mole or more of metaxylylenediamine in a diamine component and 70 moles of an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms in a dicarboxylic acid component. % Of a polyamide resin obtained by blending 0.1 to 10 parts by weight of a layered silicate (B) with respect to 100 parts by weight of a polyamide resin (A) polycondensed with a dicarboxylic acid containing at least 10% by weight. The invention relates to a molded article, wherein the layered silicate is finely dispersed in a polyamide resin by melt-kneading.

[0007] The polyamide resin (A) used in the present invention means that metaxylylenediamine is contained in the starting diamine component.
It is a polyamide resin obtained by polycondensation of a diamine containing 0 mol% or more and a dicarboxylic acid containing 70 mol% or more of α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms in a raw material dicarboxylic acid component. The polyamide resin is practically a crystalline polyamide resin.

Here, the crystalline polyamide is a crystalline polymer having a melting point, such as nylon 6 or nylon 66, and has a crystallinity, a crystallinity distribution, and a size of a spherulite which is an aggregate of crystals. , And its distribution affect the physical properties, specific gravity, dimensional stability and the like of the polyamide resin molded article. For example, these crystalline polyamides can be oriented and crystallized by stretching to increase the strength. Since the polyamide (A) used in the present invention also has a melting point and exhibits properties as a crystalline polyamide, it is useful as a material for the film, hollow container and the like of the present invention.

In the present invention, the starting diamine of the polyamide (A) contains at least 70 mol% of metaxylylenediamine. Further, in the present invention, other diamines in meta-xylylenediamine, such as aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, octamethylenediamine, nonamethylenediamine, paraphenylenediamine, metaxylylenediamine And aromatic diamines such as para-xylylenediamine and alicyclic diamines such as bis (aminomethyl) cyclohexane can be used in an amount of less than 30 mol% in all diamine components.

In the present invention, as the dicarboxylic acid component of the raw material of the polyamide (A), as the α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, for example, succinic acid, glutaric acid, pimelic acid, suberic acid, Aliphatic dicarboxylic acids such as azelaic acid, adipic acid, sebacic acid, undecandioic acid and dodecanedioic acid can be exemplified, and among these, adipic acid is preferred. The above α, ω-linear aliphatic dicarboxylic acids may contain aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, etc., in a total dicarboxylic acid component of less than 30 mol%. Can be.

The polyamide resin (A) contains 70 mol% or more of metaxylylenediamine in the starting diamine component and 70 mol of α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms in the starting dicarboxylic acid component. % Or more, it is excellent in properties such as barrier properties against gaseous substances such as oxygen and carbon dioxide when finally formed into films, sheets and hollow containers.

In the present invention, the relative viscosity of the polyamide resin (A) is preferably from 2.2 to 4.0, preferably from 2.4 to 3.7.
Is more preferred. By using a polyamide (A) having a relative viscosity of 2.2 to 4.0, the moldability when finally forming a film, sheet, or hollow container is improved.

In the present invention, the method of melt-kneading the polyamide (A) and the layered silicate (B) is not particularly limited, but a method of adding and stirring the layered silicate (B) during the melt polymerization of the polyamide resin. And a method of melt-kneading using various commonly used extruders such as a single-screw or twin-screw extruder. Among them, a method using an extruder is preferable from the viewpoint of productivity, versatility, and the like. Further, in the present invention, the melt kneading of the polyamide resin (A) and the layered silicate (B) is carried out, for example, by mixing solids such as pellets and powders as they are, putting the mixture into an extruder, and forming a sheet or film through a T-die. Either a method generally called dry blending for forming a film, or a method generally called melt blending in which solids are melted and extruded once and then repelletized as a raw material can be used. Note that the dry blend method is preferable because it has a small heat history and can reduce performance deterioration such as mechanical performance due to thermal deterioration.

In the present invention, the layered silicate (B) contained in the polyamide (A) needs to be uniformly dispersed without local aggregation. The variance here is
It means that the layered silicate separates into a plate shape in the polyamide, and that 50% or more of them have an interlayer distance of 50 angstroms or more. The interlayer distance refers to the distance between the centers of gravity of the flat objects. The longer this distance is, the better the dispersion state is, the better the appearance such as transparency when finally made into a film, sheet, or hollow container, and the better the barrier property against gaseous substances such as oxygen and carbon dioxide gas. Can be.

The layered silicate (B) used in the present invention includes a 1: 1 type layered silicate composed of one tetrahedral layer and one octahedral layer, that is, kaolinite, halloysite, chrysotile, and the like. 2: 1 type layered silicate composed of two tetrahedral layers and one octahedral layer, ie, smectites such as montmorillonite, hectorite, beidellite, savonite, mica such as muscobite, phlogovite, talc, pyrophyllite Light, vermiculite, chlorite and the like. As these layered silicates, those obtained by previously contacting a swelling agent such as a polymer compound, an organic compound or an inorganic compound to expand the interlayer may be used.

The amount of the layered silicate (B) used in the present invention is 0.1 parts by weight based on 100 parts by weight of the polyamide resin (A).
It is preferably from 10 to 10 parts by weight, more preferably from 0.5 to 8 parts by weight. When the addition amount of the layered silicate (B) is 0.1 parts by weight or more, the effect of improving gas barrier properties is exhibited, and when the addition amount is 10 parts by weight or less, transparency is not impaired.

In the present invention, the polyamide molded product comprising the mixture (C) of the polyamide resin (A) and the layered silicate (B) is a molded product which becomes a packaging material for foods, beverages, chemicals, electronic parts and the like. Examples include hollow containers such as films, sheets, bottles, cups, trays, and tanks.

The method for producing a polyamide molded product in the present invention is not particularly limited, but a melt molding method such as T-die extrusion molding and blow molding is preferred. Specifically, a method for producing an unstretched film and a sheet using a T-die extruder, a method for producing a stretched film by stretching the sheet in the machine direction and / or the transverse direction, and deep drawing from the sheet A method of manufacturing a cup, tray, etc., an injection molding machine, or a cylindrical parison using an extruder, and a method of manufacturing a bottle, a tank, etc. by blow molding the parison. However, the present invention is not limited to these methods.

In the present invention, the stretched film comprising the mixture (C) is preferably stretched to have an area stretching ratio of 4 to 16 times. When the area stretching ratio is 4 times or more, the mechanical performance is improved, and when the area stretching ratio is 16 times or less, the film can be stably manufactured without stretching and breaking.

In the present invention, it is preferable that the bottle comprising the mixture (C) is stretch-blown at an area stretching ratio of 1 to 30 times. By setting the area stretching ratio to 30 times or less, it is possible to stably manufacture without stretching fracture.

In the present invention, a polyamide molded article obtained by joining at least one layer made of the mixture (C) and at least one layer made of another thermoplastic resin is used for a food, beverage, medicine, electronic part and the like. A molded product that serves as packaging material, and can be used in multilayer films, multilayer sheets, bottles, cups,
A multilayer hollow container such as a tray or a tank may be used.

The method for forming a laminate in the present invention is a method for producing an unstretched film or sheet by coextrusion using a plurality of T-die extruders, and stretching the sheet in the machine direction and / or the transverse direction. A method for producing a stretched film, a method for producing cups and trays from the sheet by a deep drawing molding machine, a method for molding a cylindrical parison using a plurality of injection molding machines or extruders, and a blow molding for the parison. Thus, methods for producing bottles, tanks, and the like can be mentioned, but the method is not limited to these methods.

In the present invention, a lubricant such as a fatty acid amide compound, a fatty acid metal salt compound, a fatty acid amide compound, a copper compound, an organic or inorganic halogen compound, a hindered phenol compound, a hindered amine compound, etc.
It is also possible to mix additives such as antioxidants such as hydrazine-based compounds, sulfur-based compounds and phosphorus-based compounds, and ultraviolet absorbers such as benzotriazole-based compounds.

[0024]

The present invention will be specifically described below with reference to examples. In the examples and the like, the following method was used to evaluate a polyamide molded product. Relative Viscosity of Polyamide Resin A 1 g / dl 96% sulfuric acid solution was measured for relative viscosity at 25 ° C. using a Cannon-Fenske viscometer. Dispersion state A 0.1 μm-thick slice was cut out from the unstretched film with a microtome, and was measured using a transmission electron microscope J manufactured by JEOL Ltd.
The dispersion state of the layered silicate plate was photographed (100,000 times magnification) using EM-1200EX2. For 20 screens of the photographic image, the distance between the centers of gravity of adjacent flat plates was measured on a scale, and the percentage of flat plates having a distance between the centers of gravity of 50 Å or more with respect to all the flat plates in the image was obtained.

Transparency Using ZE-2000 manufactured by Nippon Denshoku Industries Co., Ltd., AST
The haze of the film was measured according to MD1003. ASTM D for stretched and unstretched films
It was measured according to 781. The measurement was made by Toyo Seiki Co., Ltd. PM
23 ° C, relative humidity 5 using an I puncture tester
The test was performed in an atmosphere of 0%. Oxygen permeability ASTM D3 for stretched film and unstretched film
It was measured according to 985. The measurement was performed using OX-TRAN 10 / 50A manufactured by Modern Control Company under an atmosphere of 23 ° C. and a relative humidity of 60%.

Example 1 Polyamide MXD6 having a relative viscosity of 2.7 (manufactured by Mitsubishi Gas Chemical Company, trade name: MX nylon 6007) 100
After dry blending 3 parts by weight of montmorillonite (trade name: Orben, manufactured by Shiraishi Industry Co., Ltd.) with a weighing feeder, the mixture is biaxially extruded with a cylinder diameter of 20 mm at a rate of 1.2 kg / hour using a weighing feeder. Machine. After melt-kneading under the conditions of a cylinder temperature of 270 ° C. and a screw rotation speed of 100 rpm, a film is extruded through a T-die, and is pulled out at a speed of 2.7 m / min.
To obtain an unstretched film having a thickness of 50 μm. Table 1 shows the physical properties of the unstretched film.

Example 2 Polyamide MXD6 having a relative viscosity of 2.7 (manufactured by Mitsubishi Gas Chemical Company, trade name: MX nylon 6007) 100
Parts by weight and 3 parts by weight of montmorillonite (trade name: Orben, manufactured by Shiroishi Kogyo Co., Ltd.), and then the mixture was biaxially extruded with a cylinder diameter of 20 mm at a rate of 2.0 kg / hour by a weighing feeder. Machine. After melt-kneading under the conditions of a cylinder temperature of 270 ° C. and a screw rotation speed of 100 rpm, the sheet is extruded through a T-die and solidified on a 70 ° C. cooling roll while being taken off at a speed of 1.0 m / min. A 300 μm sheet was obtained. The sheet was subjected to simultaneous biaxial stretching at a stretching temperature of 110 ° C. and an area magnification of 13 times with a biaxial stretching apparatus manufactured by Toyo Seiki Co., Ltd.
Further, the film was heat-set at 240 ° C. to obtain a stretched film having a thickness of 20 μm. Table 2 shows the physical properties of the stretched film.

Example 3 An unstretched film was obtained in the same manner as in Example 1 except that 100 parts by weight of the polyamide MXD6 and 5 parts by weight of montmorillonite were used. Table 1 shows the properties of the unstretched film.
Shown in

Example 4 A stretched film was obtained in the same manner as in Example 2, except that 100 parts by weight of the polyamide MXD6 and 5 parts by weight of montmorillonite were used. Table 2 shows the physical properties of the stretched film.

Example 5 An unstretched film was obtained in the same manner as in Example 1 except that 100 parts by weight of the polyamide MXD6 and 7 parts by weight of montmorillonite were used. Table 1 shows the physical properties of the unstretched film.
Shown in

Example 6 A stretched film was obtained in the same manner as in Example 2 except that 100 parts by weight of the polyamide MXD6 and 7 parts by weight of montmorillonite were used. Table 2 shows the physical properties of the stretched film.

Comparative Example 1 An unstretched film was obtained in the same manner as in Example 1 except that montmorillonite was not added. Table 1 shows the physical properties of the unstretched film.

Comparative Example 2 A stretched film was obtained in the same manner as in Example 2 except that montmorillonite was not added. Table 2 shows the physical properties of the stretched film.

Comparative Example 3 Polyamide 6 having a relative viscosity of 3.5 (Ube Industries, Ltd.)
100 parts by weight of Ube Nylon 1024B) and 3 parts by weight of montmorillonite (trade name: Orben, manufactured by Shiroishi Kogyo Co., Ltd.), and then the mixture is weighed with a weighing feeder at 1.2 kg / hour. And fed to a twin-screw extruder having a cylinder diameter of 20 mm. After melt-kneading at a cylinder temperature of 260 ° C. and a screw rotation speed of 100 rpm, the film is extruded through a T-die, solidified on a cooling roll at 20 ° C. while being drawn at a speed of 2.7 m / min. An unstretched film of 50 μm was obtained. Table 5 shows the physical properties of the unstretched film.

Comparative Example 4 Polyamide 6 having a relative viscosity of 3.5 (Ube Industries, Ltd.)
100 parts by weight of Ube Nylon 1024B) and 3 parts by weight of montmorillonite (trade name: Orben, manufactured by Shiraishi Industry Co., Ltd.), and then the mixture is weighed with a weighing feeder at 2.0 kg / hour. And fed to a twin-screw extruder having a cylinder diameter of 20 mm. After melt-kneading under the conditions of a cylinder temperature of 260 ° C. and a screw rotation speed of 100 rpm, the sheet is extruded through a T-die and solidified on a cooling roll at 20 ° C. while being drawn at a speed of 1.0 m / min. A 300 μm sheet was obtained. The sheet was stretched at a stretching temperature of 50 using a biaxial stretching apparatus manufactured by Toyo Seiki Co., Ltd.
Simultaneous biaxial stretching was attempted at an area magnification of 4 to 6 times at ８０80 ° C., but stretching was not possible due to rupture.

Comparative Example 5 An unstretched film was obtained in the same manner as in Example 1, except that the amount of montmorillonite was changed to 0.05 part by weight. Table 5 shows the physical properties of the unstretched film.

Comparative Example 6 A stretched film was obtained in the same manner as in Example 2 except that the amount of montmorillonite was changed to 0.05 part by weight. Table 4 shows the physical properties of the stretched film.

Comparative Example 7 Except that the amount of montmorillonite was changed to 15 parts by weight,
An unstretched film was obtained in the same manner as in Example 1. Table 3 shows the physical properties of the unstretched film.

Comparative Example 8 Except that the amount of montmorillonite was changed to 15 parts by weight,
A stretched film was obtained in the same manner as in Example 2. Table 4 shows the physical properties of the stretched film.

[0040]

The polyamide molded product of the present invention has transparency,
Since it has excellent gas barrier properties and mechanical performance, it is useful as a packaging material for foods, beverages, drugs, electronic components, and the like.

[0041]

[Table 1] Example / Comparative Example No. Example 1 Example 3 Example 5 Comparative Example 1 Component Resin Type N-MXD6 N-MXD6 N-MXD6 N-MXD6 Relative viscosity 2.7 2.7 2.7 2.7 Blending amount (parts by weight) 100 100 100 100 Montmorillonite (parts by weight) 3 5 7 0 Evaluation result Dispersion state (%) 98 85 70 − Haze (%) 4.0 4.1 4.3 1.4 Impact strength (kgf · cm) 1.6 1.5 1.5 1.5 Oxygen transmission coefficient (cc-mm / m2-day-atm) 0.06 0.05 0.05 0.09

[0042]

[Table 2] Example / Comparative Example No. Example 2 Example 4 Example 6 Comparative Example 2 Component Resin Type N-MXD6 N-MXD6 N-MXD6 N-MXD6 Relative viscosity 2.7 2.7 2.7 2.7 Compounding amount (parts by weight) 100 100 100 100 Montmorillonite (parts by weight) 3 5 7 0 Evaluation result Haze (%) 12 12 12 1.6 Impact strength (kgf · cm) 6.0 5.8 5.7 8.1 Oxygen permeability coefficient (cc-mm / m2-day-atm) 0.04 0.03 0.03 0.06

[0043]

[Table 3] Comparative Example No. Comparative Example 3 Comparative Example 5 Comparative Example 7 Component Resin Type N-6 N-MXD6 N-MXD6 Relative viscosity 3.5 2.7 2.7 Compounding amount (parts by weight) 100 100 100 Montmorillonite (parts by weight) 3 0.05 15 Evaluation results Dispersion state (%) 99 99 45 Haze (%) 4.0 1.5 13 Impact strength (kgf · cm) 1.6 1.5 1.5 Oxygen transmission coefficient (cc-mm / m2-day-atm) 0.07 0.09 0.09

[0044]

[Table 4] Comparative Example No. Comparative Example 4 Comparative Example 6 Comparative Example 8 Component Resin Type N-6 N-MXD6 N-MXD6 Relative viscosity 3.5 2.7 2.7 Blending amount (parts by weight) 100 100 100 Montmorillonite (parts by weight) 3 0.05 15 Evaluation result Haze (%)-2.0 20 Impact strength (kgfcm)-7.8 5.7 Oxygen permeability coefficient (cc-mm / m2-day-atm)-0.06 0.06

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/34 C08K 3/34 // B29K 77:00 B29L 7:00 9:00 22:00 F term ( Reference) 4F071 AA55 AA88 AB30 AH04 AH05 BA01 BB06 BB07 BB08 BC01 BC04 4F100 AC04A AE08A AE09A AK01B AK01C AK46A BA01 BA03 BA07 BA10B BA10C EJ37A GB15 GB16A JA06A JB16C JD02 JK01 J01A01 DJ056 FA016 FD070 GG01 GG02

Claims (6)

[Claims] 1. A diamine containing at least 70 mol% of metaxylylenediamine in a diamine component, and a dicarboxylic acid containing at least 70 mol% of an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms in a dicarboxylic acid component. A polyamide molded product obtained by molding a resin composition (C) obtained by mixing 0.1 to 10 parts by weight of a layered silicate (B) with 100 parts by weight of a polyamide resin (A) polycondensed with an acid. Characterized in that the layered silicate is finely dispersed in the polyamide resin by melt-kneading. 2. The polyamide resin (A) has a relative viscosity of:
The polyamide molded product according to claim 1, wherein the ratio is 2.2 to 4.0. 3. The polyamide molding according to claim 1, wherein the polyamide molding is a film, a sheet, or a hollow container. 4. The polyamide molded product has an area stretching ratio of 4 to 4.
The polyamide molded product according to claim 1, which is a stretched film stretched 16 times. 5. The polyamide molded product has an area stretching ratio of 1 to 5.
The polyamide molded product according to claim 1, which is a bottle stretch-blown by 30 times. 6. The polyamide molded product is a resin composition (C).
At least one layer consisting of, and a multilayer film formed by joining at least one layer made of another thermoplastic resin,
The polyamide molded product according to claim 1, which is a multilayer sheet or a multilayer container.