JP3193118B2 - Amorphous polyamide fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide fiber which has high elasticity, hardly deteriorates in physical properties when absorbing moisture, and is suitable as a reinforcing fiber for various composite materials.

[0002]

2. Description of the Related Art In general, polyamides are widely used in fiber materials, general molding materials, structural materials, etc., utilizing their excellent properties.

[0003] Polyamide fibers such as nylon 6 and nylon 66 are generally used. These have a glass transition temperature of about 50 ° C, and suddenly in a temperature range exceeding the glass transition temperature. There is a disadvantage that the elastic modulus is reduced. In addition, these have a high water absorption speed,
Since the saturated water absorption is also high, there is a disadvantage that the mechanical strength and the rigidity at the time of moisture absorption are greatly reduced.

[0004] Therefore, for various material applications in which deterioration of physical properties in a high temperature region or under moisture absorption is a problem,
It was extremely difficult to use general polyamide fibers.

[0005] Nylon 12 and the like have low water absorption, but also have a low glass transition temperature.
In a high temperature region such as at least ℃, the elastic modulus is greatly reduced.

[0006] On the other hand, amorphous polyamide is excellent in mechanical strength, impact resistance, abrasion resistance, solvent resistance, dimensional stability, insulating properties, etc. as well as transparency, so that various types of mechanical parts, It is used for equipment parts, etc., but because of its poor melt spinnability due to its amorphous nature, it has hardly ever been used alone as a fiber, especially as a multifilament. .

[0007]

SUMMARY OF THE INVENTION In view of the above points, the present invention can be widely used in various material fields and the like, and in particular, it can be used as a reinforcing fiber for various composite materials. An object of the present invention is to provide an amorphous polyamide fiber having an elastic modulus.

[0008]

The present invention has the following arrangement to solve the above-mentioned problems.

That is, the present invention provides the following three types:
And a storage shear modulus G 'in a dry state in a temperature range from room temperature to 120 ° C. is 5 × 10 ⁹ dyne / cm ² or more and boiling water at 90 ° C. or more. G ′ at room temperature to 100 ° C. in a water-absorbed state after immersion treatment for 24 hours was 4 × 10 ⁹ dy
It is an amorphous polyamide fiber composed of a polymer having a ne / cm ² or more. Isophthalic acid, 4,4'-diamino-3,3'-dimethyl cyclo f
Xylene methane ω-laurolactam

The amorphous polyamide referred to herein is different from a straight-chain aliphatic nylon such as nylon 6 or nylon 66 in that a polyamide which hardly causes crystallization of a polymer or has a very low crystallization rate is used. Point.

The amorphous polyamide is also called a transparent polyamide (transparent nylon) and gives a transparent molded article under ordinary melt molding conditions, and the molded article is subjected to post-crystallization even during heat treatment and water absorption treatment. It is a polyamide that does not cause devitrification.

The term "amorphous" as used in the present invention indicates a heat of crystal fusion of 1 cal / g or more when measured at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC). What does not exist. In the present invention, “crystalline” means:
When measured at a heating rate of 10 ° C./min using a differential scanning calorimeter, it indicates a crystal heat of fusion of 1 cal / g or more.

Further, the “glass transition temperature” in the present invention
Can also be generally determined by a differential scanning calorimeter.

Since the amorphous polyamide has no crystalline phase, its thermal properties such as heat resistance are almost dominated by the glass transition temperature (Tg). Therefore, in order to satisfy the heat resistance required for practical use, the Tg of the amorphous polyamide must be high.

The amorphous polyamide of the present invention has a Tg in a dry state of 100 ° C. to 200 ° C.

Amorphous polyamide is practically used in a temperature range below Tg where the motion of the polymer chains is frozen, and therefore has a smaller linear expansion coefficient than crystalline polyamide and is excellent in dimensional stability. .

The heat distortion temperature (HDT) also corresponds to Tg.

As with the glass transition temperature, an important physical property required for the polymer constituting the fiber in practical use is the dynamic elastic modulus. The dynamic elastic modulus of the amorphous polyamide does not change much in the temperature range of Tg or lower, and sharply decreases from the vicinity of Tg, leading to plasticization and fluidization. This viscoelastic behavior is significantly different from crystalline polyamide.

The polymer constituting the amorphous polyamide fiber of the present invention has a storage shear modulus G 'of 5 × 10 ⁹ dyne / c in a temperature range from room temperature to 120 ° C. in a dry state.
m ² or more, and even in a relatively high temperature range of, for example, 80 to 100 ° C., the decrease in physical properties is extremely small and stable.

The dry state in the present invention means that a sample is 1
This refers to a state of vacuum drying at 00 ° C. for 2 hours or more.

The behavior of an amorphous polyamide under moisture absorption is extremely specific among polyamide polymers which are considered to have a large change in properties due to moisture absorption.

Amorphous polyamide has a lower water absorption rate and a lower saturated water absorption rate than nylon 6 or nylon 66.
Therefore, the retention rate of the mechanical strength, rigidity, and electrical properties of the amorphous polyamide when absorbing moisture compared to when absolutely dry is significantly superior to that of nylon 6 or 66, and the amide group concentration is low and the moisture absorption is relatively low. Nylon 610, which is less susceptible to
Better than.

The polymer constituting the amorphous polyamide fiber of the present invention has a storage shear modulus G 'of 4 × 10 ⁹ at room temperature to 100 ° C. in a water-absorbed state immersed in boiling water at 90 ° C. or higher for 24 hours. dyne / cm ² or more, and a decrease in physical properties under moisture absorption is small and stable.

The amorphous polyamide polymer constituting the amorphous polyamide fiber of the present invention can be obtained by polycondensing a dicarboxylic acid component with a diamine component, a lactam or an amino acid.

Representative examples of the dicarboxylic acid component include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecandioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, and 5-methylisophthalic acid. Examples include acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, diglycolic acid, and the like, and mixtures thereof.

Representative examples of the diamine component include ethylenediamine, tetramethylenediamine, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-12,4,4-trimethylhexamethylenediamine, 5-methyl Nonamethylenediamine,
Meta-xylylenediamine, para-xylylenediamine,
1,3-bis (aminomethyl) cyclohexane, 1,4
-Bis (aminomethyl) cyclohexane, bis (4-aminocyclohexyl) methane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis (3-methyl-4-aminocyclohexyl) methane,
2,2-bis (4-aminocyclohexyl) propane,
Bis (aminopropyl) piperazine, bis (aminoethyl) piperazine and the like and mixtures thereof can be mentioned.

Representative examples of lactams and amino acids include lactams such as ε-caprolactam and ω-laurolactam, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, paraaminomethylbenzoic acid and the like. Amino acids, and mixtures thereof.

Among these, specific examples of the most preferable amorphous polyamide polymer used in the present invention are as follows:
And a polymer composed of three types of monomers.

Bis (3-methyl-4-aminocyclohexyl) methane isophthalate, that is, 4,4'-diamino-3,3'-dimethyldicyclohexylenemethane ω-laurolactam The amorphous polyamide fiber of the present invention is To be widely used in various material fields, etc., it is preferable to use a multifilament having 3 or more filaments, preferably 5 or more filaments in order to flexibly pass through various post-processing steps. Also, when used as reinforcing fibers for various composite materials,
A multifilament is preferable for sufficiently exhibiting its reinforcing effect.

Further, in order to widely use the amorphous polyamide fiber of the present invention in various fields of materials, etc., the tensile strength is 1 g.
/ D or more, preferably 1.5 g / d or more, and the breaking elongation is 3
0% or more, boiling water shrinkage rate of 25% or less, preferably 20%
Hereinafter, it is practically suitable that the dry heat shrinkage when subjected to dry heat treatment at 140 ° C. for 30 minutes is 20% or less, preferably 15% or less.

As a method for producing the amorphous polyamide fiber of the present invention, a known melt spinning method can be applied. In particular, the most suitable method is to spin a molten polymer immediately below a die. Provided with a heating nitrogen supply device,
This is a method in which a yarn spun from a spinneret is passed through a heated nitrogen atmosphere before being brought into contact with air, then refueled, taken up at a predetermined speed, and wound into a package.

In the production of the amorphous polyamide fiber of the present invention, no humidifying equipment such as that used for spinning nylon 6, 66 or the like is required.

[0033]

The present invention will be described below in detail with reference to examples.

Each physical property value in the examples is measured by the following method.

(Storage Shear Modulus G 'in Dry State)
First, a test piece having a width of 12 mm, a thickness of 2 mm, and a length of 60 mm is vacuum-dried at 100 ° C. for 3 hours, and a dynamic viscoelasticity analyzer, RDA-700, manufactured by Rheometrics Co., Ltd., has a substantial measurement sample length of 42 mm and a temperature rise. It was measured at a rate of 5 ° C./step.

(Storage Shear Modulus G 'in Water Absorbing State)
A test piece having a width of 12 mm, a thickness of 2 mm, and a length of 60 mm was first immersed in boiling water at 94 ° C. for 24 hours, and then immediately immersed in water at room temperature until the test piece reached room temperature. The water adhering to the surface was wiped off, and the measurement was performed in the same manner as in the dry state.

[0037] (boiling water shrinkage percentage) initial length l was immersed for 30 minutes in boiling water yarns _0, the subsequent yarn length l _1,
It was measured under a load of 1/30 (g / d) and calculated by the following equation.

[0038]

(Equation 1)

[0039] The (dry heat shrinkage) yarns of the initial length l ₀ 140
℃ placed in the hot air dryer for 30 minutes, followed by the yarn length l ₁ was measured under a load of 1/30 (g / d), was calculated by the following equation.

[0040]

(Equation 2)

(Examples 1 to 6) Isophthalic acid and 4,4 '
TR55 (manufactured by EMS, having a glass transition temperature of 15), which is an amorphous polyamide consisting of -diamino-3,3'-dimethyldicyclohexylenemethane and ω-laurolactam.
5 ° C.) The polymer chip was vacuum-dried at 120 ° C. for 14 hours, melted using an extruder, and melt-spun at a spinning speed and a spinning temperature shown in Table 1, respectively. Table 1 also shows the denier and the number of filaments of the obtained yarn.

The hole diameter of the spinneret used is 0.25 mm in Examples 1 and 2, and 0.3 mm in Examples 3 to 6, and the number of holes corresponds to the number of filaments.

In carrying out the present melt spinning,
A heating nitrogen supply device was installed directly below the base, and the nitrogen temperature was set to 140
° C, the flow rate was set to 0.1 m / sec, and the yarn spun from the spinneret was passed through a heated nitrogen atmosphere before being brought into contact with air, and then lubricated. At a spinning speed of 1. and wound up in a package.

FIG. 1 shows the results of measuring the storage shear modulus G 'of the amorphous polyamide of this example in the dry state and in the water-absorbed state.
It was shown to.

[0045]

[Table 1]

[0046]

According to the present invention, there is provided a polyamide fiber having a high modulus of elasticity up to a high temperature region and a small decrease in physical properties when absorbing moisture.

Such a fiber can be suitably used for various material applications in which the deterioration of physical properties in a high temperature region or under moisture absorption, which has conventionally been difficult, is problematic.

Further, since the polyamide fiber of the present invention can be made into a multifilament, post-processing such as knitting and weaving, which has been conventionally difficult, becomes extremely easy, and fiber structures having various forms can be easily formed. Is obtained. Therefore, in addition to the excellent properties of the amorphous polyamide itself, it can be widely applied to various industrial fields by utilizing the properties as a fiber structure.

Further, the amorphous polyamide fiber of the present invention comprises
It can be used very preferably as a reinforcing fiber for various composite materials, particularly carbon fiber composite materials using an epoxy resin as a matrix. This has the effect of improving impact resistance without lowering the modulus of elasticity of the composite material.

[Brief description of the drawings]

FIG. 1 is a view showing an example of a measurement result of a storage shear modulus G ′ of an amorphous polyamide of the present invention.

[Explanation of symbols]

A storage shear modulus in dry state B storage shear modulus in water absorption state (after immersion in boiling water at 94 ° C for 24 hours)

────────────────────────────────────────────────── ─── Continuing from the front page Examiner Toshiko Nakata (56) References JP-A-51-111897 (JP, A) JP-A-57-127734 (JP, A) JP-A-63-170418 (JP, A) 47-8181 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) D01F 6/60 C08G 69/38

Claims (3)

(57) [Claims] 1. A composition comprising the following three types of monomers:
Having a storage shear modulus G ′ of 5 × 10 in a temperature range from room temperature to 120 ° C. in a dry state.
⁹ dyne / cm ² or more, and immersed in boiling water of 90 ° C. or more for 24 hours.
An amorphous polyamide fiber comprising a polymer having a G 'at 00 ° C of 4 × 10 ⁹ dyne / cm ² or more. Isophthalic acid, 4,4'-diamino-3,3'-dimethyl cyclo f
Xylene methane ω-laurolactam 2. A contractor having the following characteristics (a) to (d):
The amorphous polyamide fiber according to claim 1. (A) Tensile strength of 1 g / d or more (b) Elongation at break of 30% or more (c) Boiling water shrinkage of 25% or less (d) Dry heat shrinkage when subjected to dry heat treatment at 140 ° C. for 30 minutes
20% or less 3. A multi-fiber having three or more filaments.
3. The amorphous polymer according to claim 1, which is a filament.
Lamide fiber.