KR100450381B1 - Process for preparing a polyamide 6 fiber stabilized to heat and light - Google Patents

Abstract

The present invention is a method for producing modified polyamide 6 for fibers having excellent thermal and ultraviolet stability.

More specifically, 0.03 to 20 parts by weight of a novel Hals-based compound of the following general formula (Ι) having a rigid adjacent amide bond in the main chain and a hals system for providing heat and UV stability to both side chains. It is prepared by adding to the blend or blended to the chip during spinning.

(Wherein R ₁ , R ₂ , R ₃ and R ₄ are the same or different alkyl groups having 1 to 6 carbon atoms)

Description

Process for preparing a polyamide 6 fiber stabilized to heat and light

The present invention relates to a method for producing modified polyamide 6 for fibers having stability against heat and ultraviolet rays.

More specifically, 0.03 to 20 weights of a novel HALS-based compound that provides stability to heat and ultraviolet rays by using 0 to 1.0 parts by weight of a mono or dicarboxylic acid component as a chain regulator in the preparation of polyamide 6. The present invention relates to a method for producing polyamide 6 having excellent heat and ultraviolet stability, characterized in that it is blended at the time of polymerization or at the time of spinning.

Minimization of trimming in the production process of polyamide fibers is very important in terms of speed and automation as well as cost reduction by productivity improvement expressed in spinning workability.

In order to improve the radioactivity, optimization of all conditions including polymerization and spinning hardware and software is essential, but of these conditions, it is most important to make the chips produced in the polymerization process suitable for the spinning process.

In order to improve the spinning workability, a method of using a polymer having thermal stability has been proposed as an alternative.

In general, polyamide is used for various purposes such as clothing, litter, film, plastic, etc. due to its excellent physical and chemical properties, but has a disadvantage of lacking stability to light.

Generally, light stabilizers that are used to improve light resistance are classified into ultraviolet absorbers, quenchers, and Hals based (Hindered Amine Light Stabilizer) according to the functional mechanism.

According to the chemical structure, it is classified into phenyl salicylates, benzophenones, benzotriazoles, nickel derivatives, and radical scavengers, and the development time is sequentially in 1945, 1953, 1956, and 1957. , 1970s.

Ultraviolet absorbers selectively absorb ultraviolet energy, convert it into infrared energy, and emit it. In general, hydroxy benzophenone, benzotriazole, and substituted acrylates are used.

The ultraviolet absorber absorbs light having a wavelength of 250 μm to 400 μm and converts the ultraviolet energy into thermal energy.

However, in the case of polymers such as thin polyolefins, light simply passes through, so in the case of products having a thickness of less than 0.1 μm, the absorbent system is less effective. Has disadvantages

The quencher system is stabilized by a UV absorber and itself emits energy as fluorescence, phosphorescence and heat. Mainly nickel compounds are used.

Hals system serves to stop the photooxidation reaction by removing the free radicals generated during the photolysis reaction.

Hals is easily oxidized, converted to nitroxyl radicals, and reacted with polymeric radicals to produce hydroxyamine ethers.

The photooxidation reaction is then stopped by reacting with peroxide radicals and regenerating stable nitroxyl radicals.

In addition, unlike absorbents, it has excellent surface protection and is applicable to products having a thin cross section, and unlike the quencher system, it is not colored.

In addition, it can be used alone and can be used in combination with the quencher.

The Hals system was originally developed in 1894 with 2,2,6,6-tetramethyl-4-oxophyteridine, and the stability of nitroxyl radicals was reported before the development of the Hals system.

In 1967, it was patented by Sankyo, Japan. In 1975, Tubabin by Shiba-gaiga. It was commercialized as. Hals reacts with the free radicals of the activating molecules to consume the radicals and to remove the radicals.

Therefore, the Hals system itself is a compound having the advantage of not being consumed while serving to remove free radicals.

Due to the advantages of Hals, domestic and foreign companies are paying attention to the new Hals stabilizer.

In order to apply the Hals system in the production of polyamide 6, a reactive amine must be present to have a binding force with the polymer.

However, the addition of Hals-based (eg 4-amino-2,2,6,6-tetramethylpiperidine) with reactive amines during polyamide polymerization presents several problems with other additives during the polymerization process due to reactive amines. Can cause.

Thus, there is a need for new novel Hals systems that are free of reactive amines and are compatible with polyamides.

Recently, BASF and Inventa-Fisher have used aromatic dicarboxylic acids (terephthalic acid or isophthalic acid) and Hals-based (4-amino-2,2,6,6-tetramethylpiperidine) during polyamide 6 polymerization. Although a method of preparing polyamide 6 having excellent thermal and ultraviolet stability has been proposed, when two additives are added together with molten caprolactam in a large-scale continuous polymerization column, polymerization is shown due to cohesiveness due to salts form. It has the difficulty of improving the hardware of the tower and the disadvantage that it can not be used for blending during spinning.

On the other hand, there is no hardware problem at the time of polymerization, and a new Halus-based additive which can be used by blending at the time of spinning has been seeded by Clariant. It was marketed as a product.

The novel Halus-based additives have excellent properties in terms of UV stability and discharge stability, but in terms of melt stability, they are slightly lower than those in which the halogen-containing and aromatic dicarboxylic acids containing reactive amines are added to the polyamide 6 polymerization phase, respectively. There is a downside to falling.

Therefore, there is an urgent need for novel Halus-based additives that can be used alone during the polymerization or spinning of polyamide 6 and that do not cause problems even when used simultaneously with the chain regulator.

There is also a need for a new Hals system with better compatibility with polyamide 6 and better melt stability.

The present invention is to solve the above-mentioned problems, heat, ultraviolet light by adding a novel Hals system having compatibility with polyamide 6 alone or together with mono or dicarboxylic acid during polymerization or spinning of polyamide 6 The present invention aims to provide a method for producing polyamide 6 that can improve the stability to the melt and further improve the melt stability and the discharge stability, and the spinning workability and the dyeing property.

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

The present invention is a novel haule for providing thermal and ultraviolet stability to both side chains having 0 to 1.0 parts by weight of mono or dicarboxylic acid as a chain modifier in the preparation of polyamide 6, and adjacent amide bonds in the main chain to give rigidity. It relates to a method for producing a modified polyamide 6 for fibers having stability against heat and ultraviolet rays, characterized in that the blend is prepared by addition of 0.03 to 20 parts by weight of the compound based on polymerization or spinning.

Structural formula of the novel Hals-based compound used in the present invention is the same as the following general formula (Ι).

Below

Wherein R ₁ , R ₂ , R ₃ , and R ₄ are the same or different alkyl groups having 1 to 6 carbon atoms

In the present invention, when using the compound of formula (Ι) at the time of polymerization, 0.1 to 20 parts by weight of water as a polymerization initiator with respect to 100 parts by weight of caprolactam alone, 0.03 to 1.0 part by weight of the compound of formula (Ι) alone It is preferably used with 0.1 to 1.0 parts by weight of mono or dicarboxylic acid as a chain regulator.

If less than 0.03 parts by weight of the compound of the general formula (I) is added in the present invention, polyamide 6 having excellent stability against heat and ultraviolet rays cannot be obtained. If it exceeds 1.0 parts by weight, the inherent physical properties of the polyamide 6 are lowered.

In the present invention, when blending the compound of the general formula (Ι) at the time of spinning, the compound of the general formula (I) may be used alone by 1.0 to 20 parts by weight, or 0.5 to 1.0 weight of mono or dicarboxylic acid. It can also be used with wealth.

When blending with less than 1.0 part by weight of the compound of formula (Ι), polyamide 6 with excellent heat and ultraviolet stability and improved dyeability cannot be obtained. If it exceeds 20 parts by weight, the inherent physical properties of polyamide 6 may be reduced. It also worsens radioactivity.

The compound of general formula (Ι) used in the present invention can increase the compatibility by generating an intermolecular hydrogen bond between two polyamide groups adjacent to the main chain and the compound of general formula (Ι). Adjacent amide groups in the compound of formula (I) itself cause intramolecular hydrogen bonds to impart very rigid properties, thereby enhancing melt stability and discharge stability.

In addition, since the compound of the formula (Ι) is dissolved in the molten caprolactam and does not have a reactive functional group with a chain modifier or other additives, it can not only eliminate the problems caused when added together, but also during spinning It can also be blended into chips.

In addition, since the compound of formula (Ι) is a Halz-based compound, it gives stability to heat and light, and can improve dyeing property when applied for medical use due to the hindered amine at the end.

In addition, a compound of the general formula (Ι) having a rigid structure as described above is introduced into the polyamide 6 molecular chain, which may additionally serve as a nucleating agent, thereby improving the strength of the polyamide 6 fiber. .

The modified polyamide 6 according to the present invention may be prepared in a reactor operated basically in a batch or continuous manner by polymerization or polycondensation, or may be prepared by blending a chip during spinning.

In the present invention, a quencher such as titanium dioxide or an antistatic agent such as polyalkylene oxide and derivatives thereof may be added as an adjuvant together with the compound of general formula (Ι).

Examples and Comparative Examples

Polyamide 6 is polymerized under the following conditions.

Polymerization temperature: 260 ~ 270 ℃

Pressure: 2 to 3.5 bar

Polymerization time: 5-6 hours

When the desired relative viscosity was reached, it was discharged, passed through a water bath, cut into chips, extracted with water, and dried in vacuum at 100 ° C. for 24 hours.

The stirrer torque indicator of the automatic reactor serves as a criterion for determining the melt viscosity of the polyamide 6.

Relative solution viscosity (RV) was measured at 25 ° C uniform temperature by dissolving 1 g of polymer per 100 ml of 95% sulfuric acid.

Thermal characteristics analysis was measured by differential scanning calorimetry (DSC) to increase the temperature to 10 ℃ / min to 280 ℃ and isothermal crystallization was measured by holding at 195 ℃ 20 minutes.

Example

To ε-caprolactam, 0.5 part by weight of terephthalic acid and 2.0 parts by weight of water and 0.15 part by weight of the compound of the following general formula (Ι) were added.

The degree of polymerization had a discharge torque of about 1.85 and the relative viscosity of the extracted and dried chips was 2.53 to 2.65.

Provided that R ₁ , R ₂ , R ₃ and R ₄ are all methyl groups (-CH ₃ ).

Comparative Example 1

0.09 parts by weight of acetic acid (CH ₃ COOH) and 2.0 parts by weight of water were added to the epsilon caprolactam. The degree of polymerization was about 1.85, and the relative viscosity of the extracted and dried chips was maintained as in Example.

Comparative Example 2

0.5 parts by weight of terephthalic acid and 2.0 parts by weight of water were added to the epsilon caprolactam to maintain the relative viscosity as in the example.

Comparative Example 3

0.5 parts by weight of terephthalic acid, 2.0 parts by weight of water, and 0.18 parts by weight of 4-AMP [4- (aminomethylpiperidine)] were added to the epsilon caprolactam, and the relative viscosity was maintained as in the example.

Comparative Example 4

0.5 parts by weight of terephthalic acid, 2.0 parts by weight of water and 0.16 parts by weight of DMAPA (3-dimethylaminopropylamine) were added to the epsilon caprolactam, and the relative viscosity was maintained as in the example.

After extracting and drying the polyamide 6 chips prepared in Examples and Comparative Examples 1 to 4, respectively, spinning through a spinneret made of SUS-316 having 24 detent holes having a diameter of 0.25 mm in an extruder having a diameter of 40 mm After spinning at a temperature of 265 ° C and a discharge rate of 43g / min, cooling by blowing air at 20 ° C at a speed of 0.6m / min to cool the oil, and then winding it at a speed of 6,000m / min to obtain 70 denier / 24 filaments. Got it.

Table 1 compares the physical properties of the chips prepared in Examples and Comparative Examples with the yarns manufactured using the chips.

<Table 1>

Classification Example Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Chip property Relative Viscosity (Dry Chip) 2.53 2.64 2.61 2.61 2.60 Crystallization rate (t1 / 2 min) 2.44 2.42 2.43 3.16 3.55 DSC Tm (℃) Tc (℃) 219.9183.3 223.0183.6 220.1183.2 221.3180.3 221.3180.3 △ R.V [chip ↔ discharger] △ 0.05 △ 0.30 △ 0.19 △ 0.22 △ 0.08 Yarn Properties Relative Viscosity (Dry Chip) 2.54 2.75 2.69 2.70 2.65 Radio workability (%) 98 54 72 60 83 Strength (g / denier) 5.61 5.22 5.38 5.35 5.55 Elongation (%) 45 44 43 42 44 Scene defects (times / 100km) 0.16 1.76 1.20 1.35 0.35 Weaving property Color fastness (grade) 4 3 4 4 4 Yellowing degree ◎ △ △ △ ○

Note) t½ minutes is crystallization time.

△ R.V (chip ↔ discharge yarn) is the relative viscosity difference between the polymer chip and the filament discharged from the nozzle.

The less ΔR.V, the better the thermal stability.

· Emissivity (%) is the percentage of regular yarn (non-trimmed yarn) to the total yarn produced within a given time.

· Scene defects: The number of defects of the yarn per 100 km generated when the scene is warped in the warper.

Yellowness: ◎: Excellent, ○: Normal, △: Poor

As can be seen from Table 1, the polymer of the polyamide 6 to which the compound of the general formula (Ι) was added has excellent melt stability, and it can be seen that the yarn property and the woven fabric property were greatly improved.

In addition, using a weathering test (Weathering Test) after irradiating the ultraviolet ray to the yarn for 200 hours, the results of measuring the strength and elongation reduction rate is shown in Table 2.

<Table 2>

Classification Example Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Strong drop rate (%) 24 ↓ 47 ↓ 43 ↓ 45 ↓ 31 ↓ % Elongation 27 ↓ 43 ↓ 44 ↓ 45 ↓ 30 ↓

As can be seen from Table 2, the polyamide 6 to which the compound of the general formula (I) was added greatly improved the resistance to ultraviolet rays due to the Halz system of both side chains of the compound of the general formula (I).

According to the present invention, when the compound of the general formula (I) is used alone or in combination with a mono or dicarboxylic acid which is a chain modifier, the polyamide 6 has improved melt stability, and is excellent in heat stability and light stability against ultraviolet rays. Can be obtained.

In addition, in the present invention, the compound of general formula (Ι) can be added at the time of polymerization or blended onto the chip during spinning, and can improve the dyeability of the polyamide 6 fiber produced by the amine groups introduced at both ends.

Claims (4)

A method for producing modified polyamide 6 having excellent heat and ultraviolet stability, characterized in that the polyamide 6 is prepared by adding a compound of formula (I) as described below during polymerization or by adding to a chip during spinning. Wherein R ₁ , R ₂ , R ₃ and R ₄ are the same or different alkyl groups having 1 to 6 carbon atoms The method for producing modified polyamide 6 having excellent heat and ultraviolet stability according to claim 1, wherein the compound of the formula (I) is added alone or in combination with a conventional chain regulator. The method for producing modified polyamide 6 having excellent heat and ultraviolet stability according to claim 2, wherein the chain modifier is one selected from mono or dicarboxylic acid, and the amount thereof is 0 to 1.0 parts by weight. The method for producing modified polyamide 6 having excellent heat and ultraviolet stability according to claim 1, wherein the amount of the compound of the formula (Ι) is 0.03 to 20 parts by weight.