JP2011157639A - Hygroscopic staple polyamide 56 fiber and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide hygroscopic staple polyamide fibers which can be produced in good spinnability and have a high commercial value. <P>SOLUTION: The hygroscopic staple polyamide 56 fibers comprising polyamide 56 as a main polymer component includes a moisture-absorbing or releasing parameter (ΔMR) of ≥4%, a fiber length of 30 to 100 mm and a crimp degree of 10 to 25%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyamide 56 short fiber having excellent hygroscopicity. More particularly, the present invention relates to a polyamide 56 short fiber that can be suitably used for materials such as stuffed cotton and non-woven fabric, inner materials made of spun yarn, and materials for clothing such as sports.

  Recently, with the increasing awareness of the environment on a global scale, the development of non-petroleum-derived fiber materials is eagerly desired. Since conventional general-purpose plastics use petroleum resources as the main raw material, global warming caused by petroleum resources being depleted in the future and mass consumption of petroleum resources has been taken up as major problems.

  By using plant resources that grow by taking in carbon dioxide from the atmosphere as a raw material, it can be expected that global warming can be suppressed by the circulation of carbon dioxide, and the problem of resource depletion may be solved. Therefore, in recent years, attention has been focused on plastics starting from plant resources, that is, plastics derived from biomass (hereinafter referred to as biomass plastics). For example, representative examples of biomass plastics include aliphatic polyesters such as polylactic acid, and research and development are active. However, aliphatic polyesters have various properties such as mechanical properties and heat resistance, which are lower than those of conventional aromatic polyester fibers or polyamide fibers, and their uses are considerably limited.

  Polyamide fibers typified by nylon 6 and nylon 66 are used in many apparel applications due to their excellent yarn strength, abrasion resistance, deep dyeability, ease of high-order processing, and the like. However, although these general-purpose polyamide fibers have relatively high hygroscopicity among synthetic fibers, their hygroscopicity is inferior compared to natural fibers, so they touch the skin directly like innerwear, pants, sports clothing, etc. Or, when used in a field worn near the skin side, there is a drawback in that it is dull and sticky due to sweating from the skin and inferior in terms of comfort compared to natural fibers.

  In order to remedy this drawback, Japanese Patent Publication No. 60-34979 proposes a method in which a hydrophilic vinyl monomer is graft-polymerized on a polyamide fiber to impart moisture absorption to improve the comfort of clothes. However, the graft-polymerized polyamide has a drawback that the dyeing fastness is lowered, and there is a problem that product development is restricted. Japanese Patent Publication No. 44-10488 discloses a technique of combining polyamide and an aliphatic block polyether amide for the purpose of improving hygroscopicity and antistatic properties, but imparts high hygroscopicity. When the block polyether amide is combined in a large amount as much as possible, the color tone of the composite fiber has a drawback that the yellowish color becomes strong and the development application is limited.

  In order to remedy this problem, Japanese Patent Laid-Open No. 6-136618 discloses a core-sheath type composite fiber in which the core component is polyetheresteramide and the sheath component is a fiber-shaped polyamide resin. According to the publication, although it is possible to exhibit excellent moisture absorption performance, the polyether ester amide of the core component is expensive to produce, and in order to exhibit sufficient moisture absorption performance, the composite ratio of the core component It was necessary to increase the value, and there was a limit to the application for deployment. Japanese Patent Application Laid-Open No. 9-188917 proposes a method of exerting a hygroscopic effect by adding 3 to 15% by weight of polyvinyl pyrrolidone in a polyamide fiber. There is a big problem that it cannot be stretched due to swelling and cannot be used.

  On the other hand, Japanese Patent Application Laid-Open No. 51-136924 proposes a core-sheath type composite staple having a hydrophilic polyester as a core component and a non-hydrophilic polyester as a sheath component. This publication uses a polyalkylene glycol copolymer alone or a small amount of a polyalkylene glycol copolymer blended with a small amount of a sulfonic acid or an acidic phosphate ester derivative as a hydrophilic polyester. This is a proposal to increase the water absorption. However, since the inventors of the present application are staples, the polyester as the sheath component is damaged in the crimping step by the crimper, and the hygroscopic resin in the core absorbs water during hot water treatment such as refining and dyeing. As a result, the fiber surface swells so that cracks occur on the fiber surface, and the core component tends to flow out to the outside.

Japanese Patent Publication No. 60-34979 Japanese Patent Publication No. 44-10488 JP-A-6-136618 Japanese Patent Laid-Open No. 9-188917 JP-A-51-136924

  The object of the present invention is to overcome the problems of the prior art and to use polyamide 56 having a high moisture absorption rate and a high melt viscosity to obtain a polyamide short fiber having good spinnability and high commercial value. It is to provide.

  The object of the present invention is a short fiber composed of polyamide 56 as a main polymer component, the moisture absorption / release parameter (ΔMR) is 4% or more, the fiber length is 30 to 80 mm, and This can be achieved with hygroscopic polyamide 56 short fibers characterized by a shrinkage of 10-25%.

  The hygroscopic short fibers obtained by the present invention have very high hygroscopic properties, and the inner and sports apparel made of spun yarns using the yarn have sufficient hygroscopic properties to obtain wearing comfort. And high dyeing fastness.

  The moisture absorption / release parameter (hereinafter referred to as ΔMR) is a scale representing the moisture absorption / release performance of the fiber, and the higher the better, the ΔMR of the hygroscopic polyamide 56 short fiber of the present invention is 4% or more. Preferably it is 6% or more.

  Here, ΔMR is a difference obtained by subtracting the moisture absorption rate (MR1) at 20 ° C. × 65% RH from the moisture absorption rate (MR2) at 30 ° C. × 90% RH (ΔMR (%) = MR2−MR1). Here, ΔMR is a driving force for obtaining comfort by releasing moisture in the clothes to the outside air when the clothes are worn, and 30 ° C. × 90% RH when performing light to medium work or light to medium exercise. The difference in moisture absorption between the temperature and humidity in the clothes represented by (1) and the outside temperature and humidity represented by 20 ° C. × 65% RH. In the present invention, this ΔMR is used as a scale indicating the hygroscopic ability as a scale for evaluating the hygroscopicity. The larger ΔMR corresponds to the higher moisture absorption / release capability and the better comfort when worn.

  The polyamide 56 short fiber of the present invention is a fiber made of polyamide 56 resin having 1,5-diaminopentane and adipic acid as main structural units. Since the polyamide 56 fiber of the present invention comprises 1,5-diaminopentane units utilizing biomass, it is excellent in environmental adaptability. In view of more excellent environmental adaptability, 50% or more of the 1,5-diaminopentane units constituting the polyamide 56 are preferably made of 1,5-diaminopentane obtained by using biomass. More preferably, it is 75% or more, and most preferably 100%.

  The cross-sectional shape of the moisture absorbing / releasing polyamide 56 short fiber of the present invention can adopt not only a round cross section but also a wide variety of irregular cross-sectional shapes such as a flat type, a Y type, an H type, a polygonal shape, and a hollow type. From the viewpoint of increasing the strength of the polyamide 56 fiber, a round cross section is preferable. However, in order to increase moisture absorption and desorption, a modified cross-sectional shape having a large fiber surface area is preferable.

  In the present invention, in order to obtain practical wearing comfort, the ΔMR of the hygroscopic short fibers is preferably as high as possible within a range in which a change with time does not cause a problem, and is 4.0% or more. Although there is no upper limit, it is about 6.5% at the highest because of the possibility of polyamide 56.

  The hygroscopic short fiber of the present invention is required to have a fiber length of 30 to 100 mm, and more preferably 35 to 80 mm. When the fiber length is too short, the entanglement between the fibers tends to be insufficient during the high-order processing. On the other hand, if the length is too long, the processability tends to be poor, including the spinning process.

  Further, the hygroscopic short fiber of the present invention needs to have a crimp degree of 10 to 25%, and more preferably 13 to 20%. If the degree of crimp is less than 10%, the entanglement between the short fibers is low, the card passing property and the spinning property are deteriorated, and it becomes difficult to exhibit sufficient bulkiness. On the other hand, if the degree of crimp exceeds 25%, the entanglement property becomes too high, and entanglement occurs, the card passing property is lowered, and the spun yarn has poor uniformity. The crimping degree can be adjusted by changing the conditions in the mechanical crimping process in the manufacturing process.

  The hygroscopic polyamide 56 short fiber of the present invention can be produced by the following method for producing a short fiber from the polyamide 56 by melt spinning.

  After the polyamide 56 is melted and discharged from the spinneret and cooled and solidified with cooling air, a water-containing oil agent is attached, subjected to stretching, heat treatment, relaxation treatment with a wet heat source, and crimped, and then a fiber length of 30 to A polyamide 56 short fiber is produced by cutting to 100 mm.

  A more specific method is illustrated. The polyamide 56 is melted, guided to a spinning pack, and spun from a discharge hole. The spun multifilament yarn is cooled and solidified, attached with a water-containing oil agent, taken up at a speed of 400 to 2000 m / min, made into a tow shape, and once stored in a can. The obtained tow was stretched more than twice in a commonly used steam bath, heat-treated, relaxed at a relaxation ratio of 0.7 to 0.95, and then mechanically crimped by an indentation method, depending on the application. Short fibers are produced by cutting to a predetermined length.

  In the present invention, as the polyamide 56 used for melt spinning, a polyamide 56 having a polymerization degree of sulfuric acid relative viscosity ηr = 2.0 to 3.0 may be used. In addition to pigments such as titanium oxide and carbon black, conventionally known antioxidants, anti-coloring agents, anti-lighting agents, antistatic agents, and the like may be added to the polyamide 56.

  The hygroscopic short fibers of the present invention are preferably used for the purpose of forming a spun yarn and then a fabric, but the fabric form can be appropriately selected according to the purpose such as a woven fabric, a knitted fabric, a non-woven fabric, and cotton padding. .

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, each characteristic value in an Example was calculated | required with the following method.

A. Hygroscopic parameters (ΔMR) of short fibers
The moisture absorption rate is 1 to 3 g of raw cotton or fabric used as a sample, and left in a constant temperature and humidity chamber for 24 hours under an absolutely dry weight and an atmosphere of 20 ° C. × 65% RH or 30 ° C. × 90% RH. Measure the weight after absorbing moisture. From the change in weight, the moisture absorption rate is obtained by the following equation.

Moisture absorption rate (%) = [(weight after moisture absorption−weight when absolutely dry) / weight when absolutely dry] × 100
The moisture absorption difference ΔMR (%) = MR2−MR1 is determined from the measured moisture absorption rates (respectively MR1 and MR2) at 20 ° C. × 65% RH and 30 ° C. × 90% RH.

B. Strength and elongation Using a Tensilon tensile tester, a stress-strain curve is obtained under the conditions of a sample length of 2 cm and a pulling speed of 2 cm / min. From this, the strength and elongation value at the time of cutting are obtained.

C. Crimp degree The length when the initial load (2 mg / d) is applied to the sample is a, the length when the load (300 mg / d) is applied is b, and the crimp degree (%) according to the following formula Is calculated. The number of tests is 10, and the average value is used.
Crimp degree (%) = [(ba) / b] × 100
Example 1 and Comparative Examples 1 and 2
Polyamide 56 is melted, discharged from a spinneret, cooled and solidified with cooling air, and then a water-containing oil agent is attached, taken at a speed of 1300 m / min to form an undrawn yarn, and once stored in a can in a tow shape did. Next, after drawing in a steam bath, heat treatment at 180 ° C., relaxation treatment, mechanical crimping by indentation method, cutting, producing short fibers with a fineness of 2.45 dtex, a fiber length of 51 mm, and a crimping degree of 15% did.

  The obtained raw cotton was used to obtain a spun yarn with a cotton count of 30 by an ordinary method. The moisture absorption / release characteristics of the spun yarn were measured and found to be ΔMR = 4.4%, which was comparable to that of cotton.

  As comparative example 1, polyamide 6 was used instead of polyamide 56, and as comparative example 2, polyamide 6 short fiber and polyamide 66 short fiber were prepared in the same manner as in Example 1 except that polyamide 66 was used instead of polyamide 56. Manufactured.

  The polyamide 6 short fiber according to Comparative Example 1 had ΔMR = 2.7%, and the polyamide 66 short fiber according to Comparative Example 2 had ΔMR = 2.5%, so that sufficient moisture absorption performance was not obtained.

Examples 2-3 and Comparative Examples 3, 4
In Example 1, the polyamide 56 short fiber was manufactured by the same method as Example 1 except having made the fineness and crimp degree constant, and having changed fiber length short or long. The results are shown in Table 2.

  In Comparative Examples 3 and 4, since the fiber length was too short or too long, problems of insufficient entanglement of spun yarn and poor process passability occurred.

Examples 4 to 5 and Comparative Examples 5 and 6
Polyamide 56 short fibers were produced in the same manner as in Example 1 except that the fiber length was fixed to 51 mm in Example 1 and the crimping degree was changed. The results are shown in Table 3.

  In Comparative Example 5, since the degree of crimping was too low, the entanglement property between the short fibers was low, the card passing property and the spinning property were deteriorated, and sufficient bulkiness was not obtained. In Comparative Example 6, since the degree of crimping was too high, the entanglement became too high, entanglement occurred, the card passing property was lowered, and the spun yarn had poor uniformity.

  The hygroscopic short fibers obtained by the present invention are suitable for comfortable bedding such as sheets, futon covers, stuffed cotton, etc., as well as non-woven fabrics for comfortable interlining, and are extremely practical.

Claims (4)

A short fiber composed of polyamide 56 as a main polymer component, a moisture absorption / release parameter (ΔMR) of 4% or more, a fiber length of 30 to 100 mm, and a crimping degree of 10 to 25%. Hygroscopic polyamide 56 short fiber characterized by being. The hygroscopic polyamide 56 short fiber according to claim 1, wherein the strength is 4 to 8 cN / dtex. After the polyamide 56 is melted and discharged from the spinneret and cooled and solidified with cooling air, a water-containing oil agent is attached, subjected to stretching, heat treatment, relaxation treatment with a wet heat source, and crimped, and then a fiber length of 30 to A method for producing a hygroscopic polyamide 56 short fiber, wherein the hygroscopic polyamide 56 short fiber according to claim 1 or 2 is produced by cutting to 100 mm. A spun yarn comprising the hygroscopic polyamide 56 short fiber according to claim 1 or 2.