JP5839290B2 - Yellowing-suppressing polyamide fiber and method for producing the same - Google Patents

Description

  The present invention relates to a yellowing-suppressing polyamide fiber and a method for producing the same.

  Polyamide fiber is a kind of relatively high strength chemical fiber. While it has wear resistance, good dimensional stability, low water absorption, moisture absorption and quick drying, it has even better elasticity (elastic recovery rate is comparable to wool) and light weight (polyamide fiber has a specific gravity of 1. 14. Among the commercial synthetic fibers, the specific gravity is less than 1 (PE and PP), and it also has corrosion resistance, insect resistance, mold resistance, etc., and it has clothing, blankets, towels, artificial leather, fishnets, fishing lines. Widely used in various areas such as.

  Polyamide fibers have the above-mentioned advantages, but also have such disadvantages as low yellowing resistance. For example, in the case of being irradiated with sunlight for a long time or in transportation, the fiber itself is easily yellowed, and thus cannot be widely applied in many fields. Further, since the shape retention is not good as compared with the polyester fiber, the obtained woven fabric is relatively weak and firm, the fiber surface has a light slip, and has a waxy feeling. In recent years, various studies have been conducted to improve the above problems. Improves light resistance by adding a light-proofing agent, or improves appearance and glossiness by making an irregular cross section, and improves texture by DTY processing or ATY processing, or blending or interweaving with other fibers The means to do is mentioned.

  Various studies have been conducted on the above yellowing problem, and it has been found that the content of amino end groups is the key to the yellowing phenomenon of polyamide fibers.

Sublimates of phenolic BHT (dibutylhydroxytoluene), an oxidation inhibitor contained in amino end groups in the fiber and packaging materials used during transport, are a series of products in the presence of catalyst NO _x (nitrogen oxide gas). Derivatives are produced, and some of the derivatives are colored derivatives, which may cause the fibers to yellow.

  In addition, the amino terminal group in the fiber and the substance obtained by dehydration reaction with vanillin contained in the packaging material used during transportation may produce a colored quinone structure in the presence of oxygen to yellow the fiber. .

  The yellowing phenomenon generated by reacting with the substances contained in the packaging material used at the time of transportation mentioned above affects the use range and field of polyamide fibers.

Further, at the stage when consumers use the polyamide textile, detergent adhering on the product, the dirt, the amino terminal groups contained polyamide fibers under NO x _(nitrogen oxide gas) catalyst present in the air Reacts with it to produce colored substances and yellow the fibers.

  Due to the above yellowing problem, polyamide fibers have an impact on service life and application fields. For example, in the clothing field, yellowing occurs, so that it cannot be applied to outerwear, and its use is limited to underwear.

  Conventionally, the following treatment has been performed for the yellowing problem caused by the amino terminal group.

  At the stage of synthesizing the polyamide, an acid substance is added to allow amino end groups to participate in the polymerization reaction, and the content of amino end groups in the polymer is lowered, thereby suppressing the occurrence of fiber yellowing phenomenon. . However, if the reaction system of the amino terminal group is changed in the polymerization stage, it is difficult to control the content of the amino terminal group. If the amino end group is excessively reduced, it becomes difficult to color at the time of dyeing, which affects the color development and the use of the fiber. In addition, the excessive amount of unreacted low molecular weight substance added affects the physical properties of the formed fiber, and the cost is greatly increased by changing the polymerization method, so that the competitiveness of the fiber market is lowered. There is.

  When the yellowing problem is improved by the finishing process at the fabric stage, the polyamide fabric is treated with an organic acid, so that some amino end groups are reacted to suppress yellowing and some amino end groups are retained. Guarantees the dyeing performance of the fabric. However, the actual treatment of the amino terminal group has a large variation, and the performance of the product cannot be controlled well. Therefore, it is considered that finishing is not a good treatment method.

  In addition, by treating the used packaging material and not containing vanillin and phenolic oxidation inhibitor BHT, a means for improving the yellowing problem of the polyamide fiber was also mentioned, but this treatment method is expensive, The impact is significant and difficult to implement.

  Conventionally, yellowing suppression treatment was also performed for the yellowing problem of polyamide fibers. In the polyamide polymerization stage, by adding an acidic substance and reacting with amino end groups, the method of reducing the content of amino end groups in the polyamide and suppressing yellowing of the polyamide fibers reduces the polymerizing ability of the polyamide. However, there is a problem that the cost is greatly increased. In addition, there is a complicated method of suppressing yellowing by treating polyamide fabric with organic acid or organic anhydride (eg: acetic acid or acetic anhydride) at the fabric stage and reducing the content of amino end groups. However, it is difficult to control. Moreover, the method of suppressing the yellowing of the polyamide fiber by selecting or improving the packaging material is very expensive and has low feasibility, and the problem of the yellowing of the polyamide fiber cannot be fundamentally solved.

  In order to improve the problems of the above-described treatment method, it is necessary to develop a technique that well solves the yellowing problem without affecting the performance of the polyamide fiber by a low-cost and simple process. Currently, the technology for adding trace amounts at the spinning stage has matured, and by controlling the content of amide end groups of polyamide fibers by adding a small amount of acidic additives at the spinning stage, the yellowing of the fibers can be suppressed. It is possible.

  The present invention provides a polyamide fiber that can suppress yellowing by controlling the amide end group content and has excellent dyeing performance, and a method for producing the same.

The present invention relates to a yellowing-suppressing polyamide fiber, containing 1.0 × 10 ^{−5 to} 3.0 × 10 ⁻⁵ mol / g amino end groups at the ends of the polyamide molecular chain and the following nitrogen-containing end group structures: and, and in the structure, R1 is an aliphatic hydrocarbon, saturated or unsaturated _C 2 _{-C 20,}

A yellowing-suppressing polyamide fiber characterized in that the above-mentioned nitrogen-containing end group structure of the polyamide molecular chain is formed by the reaction of a C ₂ -C ₂₀ carboxylic acid or derivative thereof with the terminal amino group of the base polyamide molecular chain It is.

The C ₂ -C ₂₀ carboxylic acid derivative is oxalic anhydride, malonic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, heptyl anhydride, octanoic anhydride, azelaic anhydride, sepacic anhydride, or maleic anhydride It is an acid.

  The base polyamide that reacts with dicarboxylic acid is obtained by copolymerization with terephthalic acid, so that it is possible to suppress the increase in polymer viscosity during the spinning process, and it is not necessary to suppress the increase in viscosity by controlling the moisture content of the chip. .

  The amount of dicarboxylic anhydride added is 50 to 150% of the molar content of the base polyamide molecular chain amino terminal group.

  The base polyamide is N6 or N66.

The content of the amino terminal group of the polyamide molecular chain of the fiber is 1.0 × 10 ^{−5 to} 3.0 × 10 ⁻⁵ mol / g.

  The dicarboxylic acid anhydride is continuously metered into the base polyamide at the raw material inlet of the extruder, and the base polyamide and the dicarboxylic acid anhydride are mixed, melted, reacted with the extruder, and then spun and wound.

  Using a positive displacement powder addition device, the dicarboxylic anhydride is continuously metered into the base polyamide.

  The base polyamide that reacts with the dicarboxylic acid is obtained by copolymerization with terephthalic acid.

  Polyamide 6 chips obtained by copolymerization reaction with terephthalic acid were introduced into a hopper installed immediately above the extruder, and at the same time, perpendicular to the position of 10% to 50% of the chip height from the bottom of the hopper stacking part. A carboxylic acid or a derivative thereof is continuously supplied to the polyamide in the hopper using the piping to be installed.

  In the method for producing the yellowing-suppressing polyamide fiber of the present invention, dicarboxylic acid anhydride is continuously metered into the base polyamide at the raw material inlet of the extruder, and the base polyamide and dicarboxylic acid anhydride are mixed and melted with the extruder. After reacting, spinning and winding.

  Preferably, the dicarboxylic acid anhydride is continuously metered into the base polyamide by a positive displacement powder addition device.

  The present invention also provides a method for reducing the amino end group content of the polyamide molecular chain of a polyamide fiber and includes a method of treating a base polyamide with an anhydride.

  That is, the terminal amino group content of the polyamide molecular chain of the fiber is controlled by adding a small amount of solid anhydride to the base polyamide at the melting stage of the extruder and causing a melt reaction. It also ensures that the polyamide fiber being transported and used is not yellowed, has excellent yellowing suppression performance, and the service life and area of use of the fiber are not limited. In addition, by using a powder addition device at the spinning stage and adding an end blocking agent, the amino end group content of the polyamide molecular chain of the fiber is not reduced so as to affect the dyeing. While ensuring yellowing suppression, the fiber is not affected by blocking of amino end groups and has good dyeing performance.

  Base polyamides suitable for the present invention are those termed “nylon” and long chain synthetic polymers of amide bonds (—CO—NH—) along the main polymer chain. Practical examples of the base polyamide are homopolyamide and copolyamide obtained by polymerization of lactam or amino group caproic acid, and a mixture of diamine and dicarboxylic acid or a copolymer obtained from lactam. Typical polyamides include nylon 6 [poly (ε-caprolactam)], nylon 6/6 (polyhexamethylene adipamide). The base polyamide may be nylon 6 or a copolymer of nylon 6/6 and a nylon salt. The nylon salt reacts with a dicarboxylic acid (for example, terephthalic acid, isophthalic acid, adipic acid or sepacic acid) and a diamine (for example, hexamethylenediamine, methaxylene diamine or l, 4-diaminomethylcyclohexane). Obtained. The base polyamide is preferably nylon 6 (N6) or nylon 6/6 (N66), more preferably nylon 6 (N6).

  The objects, effects, features and advantages of the present invention will become clear from the detailed description of the embodiments below. In order to facilitate an understanding of the nature of the invention, specific embodiments of the invention will be described in specific language. Such specific terms do not limit the scope of the invention. Further, modifications, improvements, equivalent replacements, and further applications to the present invention that can be normally conceived by those skilled in the art to which the present invention pertains are also included in the scope of the present invention.

  The knitted fabric made of the polyamide fiber obtained by the above-mentioned substances and methods has excellent yellowing resistance, and at the same time, the dyeing performance of the fiber itself can be secured.

  The content of amino end groups is measured by dissolving about 2.0 g of the polymer in about 60 ml of a phenol-methyl alcohol mixture (68:32). The solution is titrated by potentiometric titration using about 0.2 N HCI in an environment of about 25 ° C. The end point is determined by a rapid potential increase.

The yellowing suppression performance of polyamide fiber is divided into anti-vanillin yellowing performance, anti-NO _X yellowing performance, and anti-phenol yellowing performance, which has excellent yellowing suppression performance, maintains the whiteness of the fiber, and at the same time The fibers have better heat resistance than nylon fibers whose terminal amino groups are not blocked.

  The present invention will be described in detail by way of examples.

Example 1:
Before adding Nylon 6 (poly (ε-caprolactam)) chip (BASF400N) having a terminal amino group content of 4.2 × 10 ⁻⁵ mol / g to the extruder, use a micro-powder addition device to add N6 chip. After adding 0.3 wt% succinic anhydride, melting, mixing and reacting, it was discharged from the base through a spinning bed at 255 ° C., cooled, and wound up to obtain 56T nylon 6 fiber. The nylon 6 had a terminal amino group content of 2.22 × 10 ⁻⁵ mol / g and a nitrogen-containing terminal group structure of the following formula.

R1 is a saturated aliphatic hydrocarbon having 2 carbon atoms.

Example 2:
Before adding Nylon 6 (poly (ε-caprolactam)) chip (BASF400N) having a terminal amino group content of 4.2 × 10 ⁻⁵ mol / g to the extruder, use a micro-powder addition device to add N6 chip. After adding 0.3 wt% succinic anhydride, melting, mixing and reacting, it was discharged from the base through a spinning bed at 255 ° C., cooled, and wound up to obtain 33T nylon 6 fiber. The nylon 6 had a terminal amino group content of 1.96 × 10 ⁻⁵ mol / g, and the nitrogen-containing terminal group structure was the same as in Example 1.

Example 3:
Before adding Nylon 6 (poly (ε-caprolactam)) chip (BASF400N) having a terminal amino group content of 4.2 × 10 ⁻⁵ mol / g to the extruder, use a micro-powder addition device to add N6 chip. After adding 0.3 wt% succinic anhydride, melting, mixing, and reacting, it was discharged from the base through a spinning bed at 255 ° C., cooled, and wound up to obtain 84T nylon 6 fiber. The nylon 6 had a terminal amino group content of 1.86 × 10 ⁻⁵ mol / g, and the nitrogen-containing terminal group structure was the same as in Example 1.

Example 4:
Before adding Nylon 6 (poly (ε-caprolactam)) chip (BASF400N) having a terminal amino group content of 4.2 × 10 ⁻⁵ mol / g to the extruder, use a micro-powder addition device to add N6 chip. After adding 0.6 wt% of sepacic anhydride, melting, mixing and reacting, it was discharged from the base through a spinning bed at 255 ° C., cooled, and wound up to obtain 56T nylon 6 fiber. The nylon 6 had a terminal amino group content of 2.58 × 10 ⁻⁵ mol / g and a nitrogen-containing terminal group structure of the following formula.

R1 is a saturated aliphatic hydrocarbon of _{C 8.}

Example 5:
Before adding Nylon 6 (poly (ε-caprolactam)) chip (BASF400N) having a terminal amino group content of 4.2 × 10 ⁻⁵ mol / g to the extruder, use a micro-powder addition device to add N6 chip. After adding 0.5 wt% succinic anhydride, melting, mixing, and reacting, the mixture was discharged from the base through a spinning bed at 255 ° C., cooled, and wound up to obtain 56T nylon 6 fiber. The nylon 6 had a terminal amino group content of 2.18 × 10 ⁻⁵ mol / g, and the nitrogen-containing terminal group structure was the same as in Example 1.

Example 6:
Before adding Nylon 6 (poly (ε-caprolactam)) chip (BASF400N) having a terminal amino group content of 4.2 × 10 ⁻⁵ mol / g to the extruder, use a micro-powder addition device to add N6 chip. After adding 0.21 wt% succinic anhydride, melting, mixing, and reacting, it was discharged from the base through a spinning bed at 255 ° C., cooled, and wound up to obtain 56T nylon 6 fiber. The terminal amino group content of the nylon 6 was 2.65 × 10 ⁻⁵ mol / g, and the nitrogen-containing terminal group structure was the same as in Example 1.

Example 7:
Before adding Nylon 6 (poly (ε-caprolactam)) chip (BASF400N) having a terminal amino group content of 4.2 × 10 ⁻⁵ mol / g to the extruder, use a micro-powder addition device to add N6 chip. After adding 0.63 wt% succinic anhydride, melting, mixing and reacting, it was discharged from the base through a spinning bed at 255 ° C., cooled, and wound up to obtain 56T nylon 6 fiber. The nylon 6 had a terminal amino group content of 2.11 × 10 ⁻⁵ mol / g, and the nitrogen-containing terminal group structure was the same as in Example 1.

Example 8:
Before adding Nylon 6 (poly (ε-caprolactam)) chips (Toray T100) with a terminal amino group content of 5.4 × 10 ⁻⁵ mol / g to the extruder, use a micro-powder addition device and use N6 chips. After adding 0.3 wt% succinic anhydride to the mixture, melting, mixing and reacting, the mixture was discharged from the base through a spinning bed at 275 ° C., cooled, and wound up to obtain 56T nylon 6 fiber. The terminal amino group content of the nylon 6 was 2.65 × 10 ⁻⁵ mol / g, and the nitrogen-containing terminal group structure was the same as in Example 1.

Example 9:
Before adding a nylon 66 (N66) chip having a terminal amino group content of 3.5 × 10 ⁻⁵ mol / g to the extruder, a 0.3 wt% succinic anhydride was added to the N66 chip using a micro-powder addition device. Were added, melted, mixed and reacted, and then discharged from the die through a spinning bed at 285 ° C., cooled and wound up to obtain 56T nylon 66 fiber. The terminal amino group content of the nylon 66 was 2.31 × 10 ⁻⁵ mol / g, and the nitrogen-containing terminal group structure was the same as in Example 1.

Comparative Example 1:
Before adding Nylon 6 (poly (ε-caprolactam)) chip (BASF400N) having a terminal amino group content of 4.2 × 10 ⁻⁵ mol / g to the extruder, use a micro-powder addition device to add N6 chip. After adding 0 wt% succinic anhydride, melting, mixing and reacting, it was discharged from the base through a spinning bed at 255 ° C., cooled, and wound up to obtain 56T nylon 6 fiber. The terminal amino group content of the nylon 6 was 3.97 × 10 ⁻⁵ mol / g, and the nitrogen-containing terminal group structure was the same as in Example 1.

Comparative Example 2:
Before adding Nylon 6 (poly (ε-caprolactam)) chip (BASF400N) having a terminal amino group content of 4.2 × 10 ⁻⁵ mol / g to the extruder, use a micro-powder addition device to add N6 chip. 0.7 wt% succinic anhydride was added, melted, mixed and reacted, and then discharged from the die through a spinning bed at 255 ° C. The spinning pressure dropped significantly, the raw material leaked from the die, and could not be wound up.

Example 10:
Polyamide 6 chips obtained by copolymerization reaction with terephthalic acid were introduced into a hopper installed immediately above the extruder, and the tip height of 40 chips was added from the bottom of the hopper depositing section using a rotary powder micro-adding device. Introduce 0.3 wt% succinic anhydride into the polymer in the hopper through a pipe installed vertically at the position of%, mix with an extruder, melt and react, then discharge from the base through a spinning bed at 255 ° C. After cooling and winding, 52 DeN nylon 6 fiber was obtained. The nylon 6-terminal amino group content was 2.22 × 10 ⁻⁵ mol / g.

Example 11:
Polyamide 6 chip copolymerized with terephthalic acid was introduced into a hopper installed directly above the extruder, and 0.3 wt% anhydrous succinic acid was added to the polymer in the hopper through a pipe using a rotary powder micro-adding device. After introducing an acid, mixing, melting and reacting with an extruder, it was discharged from a base through a spinning bed at 255 ° C., cooled, and wound up to obtain 31 DeN nylon 6 fiber. The nylon 6-terminal amino group content was 1.96 × 10 ⁻⁵ mol / g.

Example 12:
In the same manner as in Example 1, 74 DeN nylon 6 fiber was obtained. The terminal amino group content of the nylon 6 fiber was 1.86 × 10 ⁻⁵ mol / g.

Example 13:
Polyamide 6 chips obtained by copolymerization reaction with terephthalic acid were introduced into a hopper installed immediately above the extruder, and 0.5 wt% anhydrous succinic acid was added to the polyamide 6 chips using a rotary powder micro-adding device. An acid was introduced, and then 52 DeN nylon 6 fiber was obtained in the same manner as in Example 1. The nylon 6-terminal amino group content was 2.18 × 10 ⁻⁵ mol / g.

Example 14:
Polyamide 6 chips obtained by copolymerization reaction with terephthalic acid were introduced into a hopper installed immediately above the extruder, and 0.7 wt% of sepasic acid was added to the polyamide 6 chips using a rotary powder micro-adding device. Then, 52DeN nylon 6 fiber was obtained in the same manner as in Example 1. The nylon 6-terminal amino group content was 2.31 × 10 ⁻⁵ mol / g.

Comparative Example 3:
Polyamide 6 chips obtained by copolymerization reaction with terephthalic acid were introduced into a hopper installed immediately above the extruder and spun without adding any additives to obtain 52 DeN nylon 6 fibers. The terminal amino group content of the nylon 6 was 3.97 × 10 ⁻⁵ mol / g.

Comparative Example 4:
Polyamide 6 chips obtained by copolymerization reaction with terephthalic acid were introduced into a hopper installed immediately above the extruder, and 1.0 wt% anhydrous succinic acid was added to the polyamide 6 chips using a rotary powder micro-adding device. The same procedure as in Example 1 was performed except that an acid was introduced. However, the spinning pressure dropped significantly, the raw material leaked from the die, and could not be wound up.

  The parameters and effects in Examples and Comparative Examples are shown in Tables 1 and 2. In Tables 1 and 2, “◯” indicates good performance, and “×” indicates poor performance.

Claims (8)

The end of the polyamide molecular chain contains 1.0 × 10 ^{−5 to} 3.0 × 10 ⁻⁵ mol / g amino end groups and the following nitrogen-containing end group structure, and in this structure, R1 is C ₂ saturated or unsaturated aliphatic hydrocarbon -C _20,

A yellowing-suppressing polyamide fiber characterized in that the above-mentioned nitrogen-containing end group structure of the polyamide molecular chain is formed by the reaction of a C ₂ -C ₂₀ carboxylic acid or derivative thereof with the terminal amino group of the base polyamide molecular chain . The C ₂ -C ₂₀ carboxylic acid derivative is oxalic anhydride, malonic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, heptyl anhydride, octanoic anhydride, azelaic anhydride, sepacic anhydride, or maleic anhydride The yellowing-suppressing polyamide fiber according to claim 1, which is an acid. That the C ₂ -C ₂₀ carboxylic acid or the base polyamide or polyamide 6 terephthalic acid is copolymerized to form a terminal group structure of nitrogen-containing derivatives thereof and reacting with the polyamide molecular chains of polyamide 66 The yellowing-suppressing polyamide fiber according to claim 1, wherein C ₂ -C amount of carboxylic acid or a derivative of ₂₀ according to claim 1 or claim 3 yellowing according variable, characterized in that 50 to 150% of the amino terminal group molar content in the base polyamide Suppressed polyamide fiber.   In the method for producing the yellowing-suppressing polyamide fiber according to claim 1, carboxylic acid or a derivative thereof is continuously metered into the base polyamide continuously at the raw material inlet of the extruder, and mixed, melted, and reacted with the extruder. A method for producing a yellowing-suppressing polyamide fiber, which is then spun and wound.   6. The method for producing a yellowing-suppressing polyamide fiber according to claim 5, wherein a carboxylic acid or a derivative thereof is continuously metered into the base polyamide using a positive displacement powder addition device. Wherein the base polyamide, the production method of the yellowing inhibition polyamide fiber according to claim 5 or claim 6, wherein the the terephthalic acid copolymerized polyamide 6 or polyamide 66.   A polyamide 6 or polyamide 66 chip copolymerized with terephthalic acid was introduced into a hopper installed directly above the extruder, and at the same time, a pipe vertically installed at a position 10% to 50% of the chip stacking height from the bottom of the hopper. The method for producing a yellowing-suppressing polyamide fiber according to claim 7, wherein the carboxylic acid or a derivative thereof is continuously supplied to the chip in the hopper.