JP3589088B2 - Sequential biaxially stretched film - Google Patents

Description

【００４０】
実施例６
６−アミノカプロン酸２０００ｇ、２，２，４−トリメチル−１，６−ジアミノヘキサンと２，４，４−トリメチル−１，６−ジアミノヘキサンとの混合物（ヒュルス社製、商品名：ベスタミンＴＭＤ）５４．８ｇ、アジピン酸５０．５ｇおよび蒸留水２００ｇを実施例１と同様の耐圧容器に仕込み窒素加圧と放圧を数回繰り返し、耐圧容器内を窒素置換してから２７０℃まで昇温した。窒素ガスを１５０ｍｌ／分で流しながら、２７０℃で撹拌下に６時間反応させた。次に、撹拌を停止し、ポリマー取出口から溶融状態のポリアミドを紐状で抜出し、水冷した後、ペレタイズして、１６００ｇのペレットを得た。このペレットを９０〜９５℃の熱水流通下で数時間洗浄した後、８０℃、２４時間真空乾燥した。得られたポリアミドのηｒは３．６３であった。このポリマーから実施例１と同様の方法でフィルムを成形し、逐次２軸延伸による二次延伸の破断時の延伸倍率は３．８倍であった。
【００４１】
【発明の効果】
ラクタムおよび／又はアミノカルボン酸からなる単位、ジカルボン酸からなる単位および２，２，４−トリメチル−１，６−ジアミノヘキサン、２，４，４−トリメチル−１，６−ジアミノヘキサン、１，２−ジアミノプロパン、１，３−ジアミノペンタン、２−メチル−１，５−ジアミノペンタン、２−メチル−１，８−ジアミノオクタン又はこれらの混合物から選ばれる分岐型飽和ジアミンを含むジアミンからなる単位を含むポリアミド、特に、ジアミンの１０〜１００ｍｏｌ％が前記分岐型飽和ジアミンであるポリアミドは延伸性に優れており、該ポリアミドから逐次二軸延伸フィルムが得られる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sequentially biaxially stretched film manufactured from a polyamide having excellent stretchability. More specifically, the present invention relates to a sequentially biaxially stretched film produced from a polyamide using a specific branched saturated diamine for part or all of the diamine.
[0002]
[Prior art]
Polyamide is used as a food packaging material such as retort foods because of its excellent heat resistance and gas barrier properties. In recent years, required properties have been diversified with the expansion of food packaging applications. For example, there is a demand for a polyamide suitable for producing a thin film having practical mechanical strength and gas barrier properties and a polyamide suitable for a sequential biaxial stretching method with good productivity.
[0003]
In general, it is known that, when a film obtained from a crystalline polymer is stretched, the thickness of the film is reduced and the mechanical strength per unit is improved. By applying this stretching technique, thin films having high mechanical strength are produced from many crystalline polymers.
However, it is known that, if films, monofilaments, fibers and the like obtained from crystalline polyamides such as nylon 6 and nylon 66 are not controlled in a certain narrow range, stretching unevenness occurs or breaks. In particular, when producing a film by the sequential biaxial stretching method which is considered to be advantageous for mass production, the polyamide molecules are oriented in parallel with the film surface in the first stretching, forming hydrogen bonds between the molecules, It is known that the crystallization proceeds and the film becomes hard, so that the second-stage stretching becomes difficult. Therefore, a polyamide having improved stretchability that can be easily applied to the sequential biaxial stretching method is desired.
[0004]
Conventionally, there have been many proposals for improving the stretchability of polyamide. For example, JP-A-52-104565 discloses that a film obtained by melt-molding a blend of an aliphatic polyamide and a polyamide comprising xylylenediamine and α, ω-aliphatic dicarboxylic acid is used to obtain a film having a plane orientation index. Is stretched in the first stage (also referred to as “primary stretching”) so that the film thickness becomes 0.6 to 1.5, and then the film is stretched in the second stage (also referred to as “secondary stretching”). Has been proposed. JP-B-55-41901 discloses blending an aliphatic polyamide with another polyamide compatible with the polyamide and a nucleating agent in an amount such that an isothermal crystallization parameter is 1.1 to 2.5. A method for producing a sequentially biaxially stretched film has been proposed in which the film is primarily stretched so that the plane orientation index is 0.6 to 1.5, and then is secondarily stretched. JP-B-62-25704 discloses an aliphatic polyamide and 2,2,4-trimethyl-1,6-hexamethylenediamine and / or 2,4,4-trimethyl-1,6-hexamethylenediamine and an aromatic polyamide. And / or a method for producing a stretched film obtained from a blend of polyamide with an alicyclic dicarboxylic acid at a specific ratio. Japanese Patent Publication No. 43552/1994 discloses a blend obtained from a copolymer of an aliphatic polyamide and a semi-aromatic polyamide, an aliphatic diamine and a semi-aromatic polyamide of isophthalic acid and / or terephthalic acid. A polyamide composition suitable for a biaxially stretched film has been proposed.
[0005]
Conventionally, the stretchability of a proposed polyamide composition or the like is improved as compared with a single polyamide such as nylon 6. However, when the stretching ratio of the film is 3 times or more, stretching unevenness may occur, or there is a limit to the stretching ratio at which good stretching can be performed. Also, when the second-stage stretching (secondary stretching) in the sequential biaxial stretching method, that is, when stretching is performed in a direction perpendicular to the stretching direction of the primary stretching, stretching unevenness is likely to occur or the film is broken at a low stretching ratio. However, improvement in stretchability was not yet sufficient.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a sequentially biaxially stretched film produced from a polyamide having excellent stretchability.
[0007]
[Means for Solving the Problems]
The present inventors have conducted extensive studies on the relationship between the molecular structure of the polyamide and the extensibility of polyamides having excellent stretchability, particularly excellent sequential biaxial stretchability. Have been found to be polyamides having good sequential biaxial stretching properties to achieve the object of the present invention, and have reached the present invention.
[0008]
That is, the first invention of the present invention relates to a unit comprising lactam and / or aminocarboxylic acid, a unit comprising dicarboxylic acid, and 2,2,4-trimethyl-1,6-diaminohexane, 2,4,4- Selected from trimethyl-1,6-diaminohexane, 1,2-diaminopropane, 1,3-diaminopentane, 2-methyl-1,5-diaminopentane, 2-methyl-1,8-diaminooctane or a mixture thereof And a unit comprising a diamine containing a branched saturated diamine.
[0009]
A second invention is the sequential biaxially stretched film according to the first invention, wherein 10 to 100 mol% of the diamine is the branched saturated diamine.
[0010]
A third invention is a polyamide containing 50 to 99.8 mol% of lactam and / or aminocarboxylic acid, 0.1 to 25 mol% of dicarboxylic acid, and 0.1 to 25 mol% of diamine, wherein 10 to 100 mol% of the diamine. Is 2,2,4-trimethyl-1,6-diaminohexane, 2,4,4-trimethyl-1,6-diaminohexane, 1,2-diaminopropane, 1,3-diaminopentane, 2-methyl- It is a sequential biaxially stretched film produced from a polyamide which is a branched saturated diamine selected from 1,5-diaminopentane, 2-methyl-1,8-diaminooctane or a mixture thereof.
[0011]
The reason why the polyamide having the branched saturated diamine as a structural unit is excellent in stretchability, in particular, the conventional biaxial stretchability, which has conventionally been difficult, is not clear, but the branching of the diamine unit introduced into the polyamide molecular chain is not clear. Is presumed to weaken the hydrogen bonding interaction between the polyamide molecules during stretching, suppress the orientation of the polyamide molecules in the film plane, and suppress crystallization. This indicates that the polyamide of the present invention is better than the polyamide of the present invention containing the branched saturated diamine as an essential component and the degree of orientation of all molecular planes of films having substantially the same stretching ratio obtained from nylon 6. It is presumed as described above also from the low plane orientation of the molecules.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail. The polyamide of the present invention comprises a unit composed of lactam and / or aminocarboxylic acid, a unit composed of dicarboxylic acid, and 2,2,4-trimethyl-1,6-diaminohexane, 2,4,4-trimethyl-1,6. Branched saturated diamine selected from -diaminohexane, 1,2-diaminopropane, 1,3-diaminopentane, 2-methyl-1,5-diaminopentane, 2-methyl-1,8-diaminooctane or a mixture thereof And a diamine unit containing:
[0013]
The lactam used in the present invention includes ε-caprolactam, ω-enantholactam, ω-undecalactam, ω-dodecalactam, 2-pyrrolidone and the like. Examples of the aminocarboxylic acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 10-aminocapric acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. These lactams and amino acids may be used alone or in combination of two or more. When lacram and aminocarboxylic acid are used in combination, they can be mixed and used at an arbitrary ratio. A polyamide comprising a polyamide derived from a lactam and / or an aminocarboxylic acid and a polyamide having a branched saturated diamine having 6 to 22 carbon atoms has a stretchability even when the content of the latter is small. Be improved.
[0014]
Specific examples of the dicarboxylic acid used in the present invention include adipic acid, suberic acid, azelaic acid, sebacic acid, aliphatic dicarboxylic acids such as dodecanoic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. Examples include aromatic dicarboxylic acids such as alicyclic dicarboxylic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid. These dicarboxylic acids may be used alone or in combination of two or more. Is also good.
[0015]
The branched saturated diamine used in the present invention includes 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 1,2-diaminopropane, 3-diaminopentane, 2-methyl-1,5-diaminopentane and 2-methyl-1,8-diaminooctane or a mixture thereof.
[0016]
Examples of the diamine other than the branched saturated diamine include aliphatic diamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, bis (4-aminocyclohexyl) methane, and bis ( 4-aminocyclohexyl) propane, 1,3-bisaminomethylcyclohexane, alicyclic diamines such as 1,4-bisaminomethylcyclohexane, meta-xylylenediamine, aromatic diamines such as para-xylylenediamine, and the like, These diamines may be used alone or in combination of two or more. The dicarboxylic acid and the diamine containing the branched saturated diamine are used in an approximately equimolar ratio.
[0017]
The amount of lactam and / or aminocaproic acid used is 50 to 99.8 mol%, preferably 70 to 99.5 mol%, dicarboxylic acid is 0.1 to 25 mol%, preferably 0.25 to 15 mol%, and diamine is 0 to 9 mol%. 0.1 to 25 mol%, preferably 0.25 to 15 mol%. Also, 10 to 100 mol%, preferably 30 to 100 mol%, more preferably 50 to 100 mol% of the diamine is the branched saturated diamine. If the amount of the lactam and / or aminocarboxylic acid is less than the above lower limit, the mechanical strength may decrease. In addition, if it exceeds the above upper limit, the stretchability may decrease. If the amount of the branched saturated diamine in the diamine is less than the above lower limit, the stretchability will decrease. On the other hand, when it exceeds the upper limit, the stretchability is good, but practical physical properties such as mechanical strength are reduced.
[0018]
The production of the polyamide of the present invention can be carried out batchwise or continuously, and can be carried out in a batch reactor, a single-tank or multilayer continuous reactor, a tubular continuous reactor, a single-screw kneading extruder, or a twin-screw kneading extruder. A known polyamide production apparatus such as a kneading reaction extruder can be used. Known polymerization methods such as melt polymerization, solution polymerization, and solid phase polymerization can be used as the polymerization method. These polymerization methods can be used alone or in an appropriate combination.
[0019]
For example, a lactam and / or an aminocarboxylic acid, a dicarboxylic acid, a diamine containing the branched saturated diamine and water are charged in a pressure-resistant container, and polycondensed under pressure in a sealed temperature range of 200 to 350 ° C. By lowering the pressure and continuing the polycondensation reaction in the temperature range of 200 to 350 ° C. under atmospheric pressure or reduced pressure to increase the molecular weight, the desired polyamide can be produced. At this time, the diamine and the dicarboxylic acid may be directly charged in a pressure-resistant container, or, after mixing and dissolving substantially equimolar diamine and dicarboxylic acid in water or alcohol, a nylon salt is formed, and the solution state as it is or A concentrated solution state or a solid nylon salt obtained by recrystallization may be charged. As the water used in the present invention, it is desirable to use ion-exchanged water or distilled water from which oxygen has been removed, and the amount used is generally 1 to 150 parts by weight based on 100 parts by weight of the raw material constituting the polyamide. .
[0020]
The high molecular weight polyamide is usually withdrawn from the reaction vessel in a molten state, cooled with water or the like, and then pelletized. In the case of pellets mainly composed of polyamide containing a large amount of unreacted monomers such as nylon 6, the unreacted monomers and the like are further removed by hot water washing or the like, and then used for film production. The molecular weight of the polyamide of the present invention is in the range of 1.5 to 5.0, preferably 2.0 to 4.5, in terms of relative viscosity (ηr) measured by the method described in JIS K6810. In addition, there is no special restriction on the kind of the terminal group of the polyamide and its concentration or molecular weight distribution.
[0021]
During the polymerization of the polyamide of the present invention, if necessary, a phosphorus-based compound such as phosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, metaphosphoric acid or an alkali metal salt thereof is added for promoting polymerization or preventing oxidation. can do. The addition amount of these phosphorus compounds is usually 50 to 3,000 ppm based on the polyamide to be obtained. In addition, amines such as laurylamine, stearylamine, hexamethylenediamine, metaxylylenediamine, acetic acid, benzoic acid, stearic acid, hexanedioic acid, isophthalic acid, terephthalic acid, etc. are used for controlling the molecular weight and stabilizing the melt viscosity during molding. A carboxylic acid such as an acid can be added. The amount of these molecular weight regulators varies depending on the reactivity of the molecular weight regulator and the polymerization conditions, but is appropriately determined so that the relative viscosity of the polyamide finally obtained is in the range of 1.5 to 5.0. .
[0022]
The film can be produced from the polyamide of the present invention by a known film production method, for example, a T-die method using a melt extruder, an inflation method, a tubular method, a solvent casting method, a hot press method, or the like. The melting temperature of the polyamide by a method using a melt extruder is from the melting point of the polyamide used to 320 ° C.
[0023]
In the case of producing a film by the sequential biaxial stretching method, the polyamide of the present invention, if necessary, after adding a lubricant such as calcium stearate, a bisamide compound, silica, talc, a slip agent, a nucleating agent, and the like, a T die is provided. The polyamide is melt-extruded by an extruder to form an unstretched film. The unstretched film may be continuously stretched in a continuous process, or may be wound up and then stretched. The stretching is performed at a temperature equal to or higher than the glass transition temperature (hereinafter referred to as Tg) of the polyamide used. The first-stage stretching (primary stretching) of the sequential biaxial stretching is performed in a temperature range of Tg to (Tg + 50) ° C. in the extrusion direction of the film by 2 to 5 times, preferably 2.5 to 4 times. Then, the second-stage stretching (secondary stretching) performed in a direction perpendicular to the extrusion direction of the film is performed at the same or slightly higher temperature as the primary stretching at a stretching ratio of 2 to 5 times, preferably 2.5 times. Stretched up to 4 times. Then, it is heat-set at a temperature of 150 ° C. or more, and a successively biaxially stretched film is obtained.
[0024]
Heat stabilizers, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, tackifiers, sealability improvers, antifoggants, release agents are added to the polyamides of the present invention within the range in which the effects of the present invention are not impaired. Molding agents, impact modifiers, plasticizers, pigments, dyes, fragrances, reinforcing materials and the like can be added.
[0026]
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The measured values shown in the examples and comparative examples were measured by the following methods.
[0027]
1) Measurement of ηr (Relative Viscosity) of Polyamide According to JIS K6810, measurement was performed at a temperature of 25 ° C. using 98 wt% concentrated sulfuric acid as a solvent at a polyamide concentration of 1 wt / vol% using an Ubbelohde viscometer.
[0028]
2) Measurement of the degree of orientation of all molecular planes when the film is stretched (primary stretching) in the extrusion direction of the film A biaxial stretching machine BIX-703 (Iwamoto) whose temperature is controlled to a predetermined atmospheric temperature (50 ° C., 60 ° C., 70 ° C.) An unstretched sample film having a length of 92 mm and a width of 92 mm was attached to a stretching tank (manufactured by Seisakusho Co., Ltd.), preheated at ambient temperature for 20 seconds, and stretched 3.2 times in the extrusion direction of the film at a deformation speed of 35 mm / sec ( (Primary stretching) and heat-setting at 200 ° C. to prepare a test film for measuring the degree of orientation of all molecular planes. The refractive index (Nx) in the stretching direction, the refractive index (Ny) in the width direction, and the refractive index (Nz) in the thickness direction of this film were measured with an automatic birefringence meter KOBRA-21ADH type (manufactured by Oji Scientific Instruments), and The total molecular plane orientation (P) was determined by (1).
(Equation 1)
P = {(Nx + Ny) / 2} −Nz Equation (1)
(Where P is the total molecular plane orientation of the stretched film, Nx is the refractive index in the stretching direction of the film, Ny is the refractive index in the width direction of the film, and Nz is the refractive index in the thickness direction)
The smaller the value of P, the lower the orientation of the polyamide molecules and the better the stretchability.
[0029]
3) Measurement of stretching ratio at the time of breaking of secondary stretching by sequential biaxial stretching method A sample film was attached to a stretching tank of a biaxial stretching machine BIX-703 (manufactured by Iwamoto Seisakusho) adjusted to an atmosphere temperature of 60 ° C. After preheating at ambient temperature for 20 seconds, the first stage of stretching (primary stretching) is performed 3.0 times at a deformation speed of 35 mm / sec in the extrusion direction of the film, and subsequently, the deformation speed is 35 mm / sec in a direction perpendicular to the extrusion direction. The second-stage stretching (secondary stretching) was performed in seconds until the film was broken, and the stretching ratio at the time of breaking was measured.
[0030]
Example 1
In a 5 liter pressure vessel equipped with a stirrer, thermometer, pressure gauge, pressure controller and polymer outlet, 2200 g of ε-caprolactam, 2,2,4-trimethyl-1,6-diaminohexane and 2,4,4- 41.2 g of a mixture with trimethyl-1,6-diaminohexane (manufactured by Huls, trade name: Vestamine TMD), 38 g of adipic acid and 120 g of distilled water were charged, and nitrogen pressurization and depressurization were repeated several times. Was replaced with nitrogen, and the temperature was raised to 240 ° C. After reacting at 240 ° C. with stirring for 4 hours, the temperature was raised to 270 ° C., and the gauge pressure was released to 0 kg / cm ² · G over 2 hours. Then, while flowing nitrogen gas at 150 ml / min, The reaction was carried out at 270 ° C. with stirring for 6 hours. Next, the stirring was stopped, the polyamide in a molten state was pulled out from the polymer outlet in the form of a string, cooled with water, and then pelletized to obtain about 1800 g of pellets. The pellets were washed for several hours under flowing hot water at 90 to 95 ° C., and then vacuum dried at 80 ° C. for 24 hours. Ηr of the obtained polyamide was 3.13.
To 1500 g of this polyamide, 0.45 g of calcium stearate was mixed and supplied to an extruder equipped with a coat hanger type T die. The mixture was melt-kneaded at 260 ° C. and extruded onto a cooling roll controlled at about 35 ° C. to produce a 120 μm-thick unstretched film. The unstretched film was placed in an aluminum bag so as not to absorb moisture until the stretchability was evaluated, and stored at 0 ° C. or lower. A sample having a length of 92 mm and a width of 92 mm cut out from the unstretched film was mounted on a biaxial stretching machine BOX-703 (manufactured by Iwamoto Seisakusho) and preheated at an ambient temperature of 60 ° C. for 20 seconds. The film was stretched (primary stretching) three times in the extrusion direction of the film in seconds. The degree of orientation in all molecular planes of the obtained stretched film was measured. Table 1 shows the results.
A film obtained by primary stretching 3.0 times in the extrusion direction at an ambient temperature of 60 ° C. and a deformation speed of 35 mm / sec is broken at the same temperature in the direction perpendicular to the extrusion direction at the same deformation speed of 35 mm / sec as the primary stretching. The film was secondarily stretched. The stretching ratio at the time of secondary stretching breaking was 4 times.
[0031]
Example 2
12.2200 g of ε-caprolactam, a mixture of 2,2,4-trimethyl-1,6-diaminohexane and 2,4,4-trimethyl-1,6-diaminohexane (trade name: Vestamine TMD, manufactured by Huls) A polyamide was obtained in the same manner as in Example 1 except that 0 g, 12.1 g of adipic acid and 100 g of distilled water were charged into a pressure-resistant container. Ηr of this polyamide was 3.47. The degree of orientation in all molecular planes of a film produced from this polyamide in the same manner as in Example 1 was measured. Table 1 shows the results.
The stretching ratio at the time of breaking of the secondary stretching by sequential biaxial stretching measured in the same manner as in Example 1 was 3.5 times.
[0032]
Example 3
18.2200 g of ε-caprolactam, a mixture of 2,2,4-trimethyl-1,6-diaminohexane and 2,4,4-trimethyl-1,6-diaminohexane (trade name: Vestamine TMD, manufactured by Huls) A polyamide was obtained in the same manner as in Example 1 except that 7 g, 3.6 g of hexamethylenediamine, 25.9 g of isophthalic acid and 110 g of distilled water were charged into a pressure-resistant container. Ηr of this polyamide was 3.51. The degree of orientation in all molecular planes of a film produced from this polyamide in the same manner as in Example 1 was measured. Table 1 shows the results.
Further, the stretching ratio at the time of breaking of the secondary stretching by the sequential biaxial stretching measured in the same manner as in Example 1 was 3.0 times.
[0033]
Example 4
A polyamide was obtained in the same manner as in Example 1 except that 2,200 g of ε-caprolactam, 30.1 g of 2-methyl-1,5-diaminopentane, 37.9 g of adipic acid and 118 g of distilled water were charged into a pressure-resistant container. Was. Ηr of this polyamide was 3.55. The degree of orientation in all molecular planes of a film produced from this polyamide in the same manner as in Example 1 was measured. Table 1 shows the results.
Further, the stretching ratio at the time of breaking of the secondary stretching by sequential biaxial stretching measured in the same manner as in Example 1 was 3.3 times.
[0034]
Example 5
A polyamide was obtained in the same manner as in Example 1 except that 2200 g of ε-caprolactam, 35.4 g of 2-methyl-1,8-diaminooctane, 32.6 g of adipic acid and 118 g of distilled water were charged into a pressure-resistant container. Was. Ηr of this polyamide was 3.55. The degree of orientation in all molecular planes of a film produced from this polyamide in the same manner as in Example 1 was measured. Table 1 shows the results.
Further, the stretching ratio at the time of breaking of the secondary stretching by the sequential biaxial stretching measured in the same manner as in Example 1 was 3.0 times.
[0035]
Comparative Example 1
A polyamide (nylon 6) was obtained in the same manner as in Example 1 except that 2,200 g of ε-caprolactam and 116 g of distilled water were charged into a pressure-resistant container. Ηr of this polyamide was 3.57. The degree of orientation in all molecular planes of a film produced from this polyamide in the same manner as in Example 1 was measured. Table 1 shows the results.
The stretching ratio at the time of breaking of the secondary stretching by sequential biaxial stretching measured in the same manner as in Example 1 was 1.3 times.
[0036]
Comparative Example 2
Except that 2200 g of ε-caprolactam, 30.1 g of hexamethylenediamine, 38.9 g of adipic acid and 119 g of distilled water were charged into a pressure-resistant container, the same procedure as in Example 1 was carried out to obtain a polyamide (copolymer of nylon 6 and 66). (Polymer) was obtained. Ηr of this polyamide was 3.50. The degree of orientation in all molecular planes of a film produced from this polyamide in the same manner as in Example 1 was measured. Table 1 shows the results.
Further, the stretching ratio at the time of breaking of the secondary stretching by sequential biaxial stretching measured in the same manner as in Example 1 was 2.5 times.
[0037]
[Table 1]

[0040]
Example 6
2000 g of 6-aminocaproic acid, a mixture of 2,2,4-trimethyl-1,6-diaminohexane and 2,4,4-trimethyl-1,6-diaminohexane (trade name: Vestamine TMD, manufactured by Huls) 54 8.8 g, adipic acid 50.5 g and distilled water 200 g were charged into the same pressure-resistant container as in Example 1, and nitrogen pressurization and depressurization were repeated several times. After the inside of the pressure-resistant container was replaced with nitrogen, the temperature was raised to 270 ° C. The reaction was carried out at 270 ° C. for 6 hours with stirring while flowing nitrogen gas at 150 ml / min. Next, stirring was stopped, the polyamide in a molten state was pulled out from the polymer outlet in a string form, cooled with water, and then pelletized to obtain 1600 g of pellets. The pellets were washed for several hours under flowing hot water at 90 to 95 ° C., and then vacuum dried at 80 ° C. for 24 hours. Ηr of the obtained polyamide was 3.63. A film was formed from this polymer in the same manner as in Example 1, and the stretching ratio at the time of breaking in secondary stretching by sequential biaxial stretching was 3.8 times.
[0041]
【The invention's effect】
Lactam and / or aminocarboxylic acid units, dicarboxylic acid units and 2,2,4-trimethyl-1,6-diaminohexane, 2,4,4-trimethyl-1,6-diaminohexane, 1,2 A unit comprising a diamine containing a branched saturated diamine selected from -diaminopropane, 1,3-diaminopentane, 2-methyl-1,5-diaminopentane, 2-methyl-1,8-diaminooctane or a mixture thereof; Polyamides, particularly polyamides in which 10-100 mol% of the diamine is the branched saturated diamine, are excellent in stretchability, and a sequential biaxially stretched film can be obtained from the polyamide.

Claims (3)

A unit composed of a lactam and / or an aminocarboxylic acid, a unit composed of a dicarboxylic acid, and 2,2,4-trimethyl-1,6-diaminohexane, 2,4,4-trimethyl-1,6-diaminohexane, A unit comprising a diamine containing a branched saturated diamine selected from 2-diaminopropane, 1,3-diaminopentane, 2-methyl-1,5-diaminopentane, 2-methyl-1,8-diaminooctane or a mixture thereof. A biaxially stretched film produced from a polyamide containing: The sequential biaxially stretched film according to claim 1, wherein 10 to 100 mol% of the diamine is a branched saturated diamine. A polyamide comprising 50 to 99.8 mol% of lactam and / or aminocarboxylic acid, 0.1 to 25 mol% of dicarboxylic acid, and 0.1 to 25 mol% of diamine, wherein 10 to 100 mol% of the diamine is 2,2,2 . 4-trimethyl-1,6-diaminohexane, 2,4,4-trimethyl-1,6-diaminohexane, 1,2-diaminopropane, 1,3-diaminopentane, 2-methyl-1,5-diaminopentane , 2-methyl-1,8-diaminooctane or a polyamide which is a branched saturated diamine selected from a mixture thereof .