JPH04222220A - Durably hydrophilic hot-melt conjugate fiber - Google Patents

Abstract

PURPOSE:To obtain the subject fiber having low dissolution tendency by using a sheath component produced by adding a specific hydrophilic modifier to a specific amorphous copolyester. CONSTITUTION:The objective conjugate fiber is composed of a sheath component (a) consisting of an amorphous polyester incorporated with 0.2-20wt.% of a hydrophilic modifier and a core component (b) consisting of a thermoplastic polymer having a melting point of >=150 deg.C at a weight ratio (sheath:core) of 20:80 to 80:20. The hydrophilic modifier is a compound containing a group having a polyalkylene oxide chain bonded to a polyalkylene polyamine skeleton and has an HLB of 6.0-16.0, an average molecular weight of >=10,000 and an amine value of <=500. The polyester used as the sheath component has a second order transition temperature of 50-90 deg.C and a heat of crystal melting of essentially zero and contains >=40mol% of TA unit and >=20mol% of isophthalic acid unit in the acid unit and >=75mol% of ethylene glycol unit in the glycol unit.

Description

Detailed Description of the Invention [0001] [Industrial Application Field] The present invention relates to a heat-adhesive conjugate fiber having excellent hydrophilicity. An object of the present invention is to provide a polyester-based heat-adhesive conjugate fiber that has excellent hydrophilicity and is safe. BACKGROUND OF THE INVENTION Heat-adhesive conjugate fibers for producing nonwoven fabrics and the like by interfiber thermal fusion have been known. For example, there are polyethylene-polypropylene composite fibers containing polyethylene as an adhesive component, composite fibers with polypropylene containing copolymerized nylon as an adhesive component, composite fibers with polyethylene terephthalate containing an ethylene-vinyl alcohol copolymer as an adhesive component, and the like. [0003] In recent years, the role of polyester fibers such as polyethylene terephthalate has been growing in the textile field, particularly in the nonwoven fabric field, and from the viewpoint of production efficiency and energy saving, there is a growing demand for fiber aggregates or textile products, especially nonwoven fabrics, by thermal bonding. Therefore, adhesive fibers for polyester are strongly desired. Therefore, various types of copolymerized polyester heat-fusible fibers that use polyester as an adhesion partner have been developed. It has not been developed yet. [0004] Especially recently, baby diapers and diaper liners,
The field of sanitary materials such as sanitary products, the field of non-hygienic materials such as counter cloths for the restaurant industry, drainage bags for sinks for kitchen utensils, and the field of medical products such as base fabrics and fixing sheets for medical supplies, surgical gowns for hospitals, and masks. Non-woven fabrics have been widely used in Among these many nonwoven products, especially those such as baby diapers and sanitary products,
Hydrophilic properties that were more durable than conventional products were required. However, most of the products to date have been processed after surface treatment using a hydrophilic oil, etc., and although this has good initial performance, after a certain amount of use, the surface oil falls off and the performance deteriorates dramatically. There were many things. [0005] Among these, wet-type nonwoven fabric applications for diaper surface materials and sanitary pad surface materials always undergo a papermaking process in water during the manufacturing process. The hydrophilizing agent falls off, and the final product is only one that does not maintain sufficient performance. Furthermore, when a hydrophilic material such as wood pulp or rayon is mixed and the heat-fusible fiber is hydrophobic, there is a problem that the resulting nonwoven fabric or sheet loses its hydrophilicity. [0006] Recently, it has been proposed to knead polyoxyalkylene glycol, which is a hydrophilic agent, and a metal sulfonic acid derivative into a modified polyester to impart durable liquid absorption and liquid retention properties. However, when wet wipe nonwoven fabrics made of modified polyester fibers containing metal sulfonate derivatives, etc., are soaked in a wetting agent such as hydrous alcohol, a large amount of the metal sulfonate derivatives kneaded into the fibers is released. There was a problem with elution. When the nonwoven fabric is used, it contaminates the object to be wiped, and when used on the body, hygiene and safety problems arise. [0007] An object of the present invention is to maintain the performance of polyester heat-adhesive fibers that can be thermally bonded to polyester fibers, and to improve the performance of both dry-laid and wet-laid nonwoven fabrics obtained. Another object of the present invention is to provide a heat-fusible fiber having extremely excellent hydrophilic durability and whose hydrophilicity does not substantially decrease even after washing with water or hot water. Furthermore, it is an object of the present invention to provide a durable hydrophilic heat-fusible fiber in which the hydrophilizing agent is less eluted from the fiber and the eluted material does not pose a safety problem to the human body. [0008] Another object of the present invention is to obtain a nonwoven fabric or sheet using heat-fusible fibers using hydrophilic materials such as wood pulp, viscose rayon, or vinylon. An object of the present invention is to provide a heat-fusible fiber having excellent hydrophilic durability and capable of exhibiting hydrophilicity without impairing the hydrophilicity of a hydrophilic material. Means for Solving the Problems The heat-fusible fiber of the present invention is a compound in which a group having a polyalkylene oxide chain is bonded to a polyalkylene polyamine skeleton, and satisfies specific conditions. A predetermined amount of the compound is contained and dispersed in an amorphous copolymerized polyester that is a specific polymer and has specific polymer physical properties, and the amorphous copolymerized polyester is used as a sheath component, and the melting point is 150 ° C. or higher. It is a thermoadhesive conjugate fiber having durable hydrophilic properties, which is characterized by having a thermoplastic polymer as a core component and making it into a conjugate fiber. That is, the present invention comprises a polyester containing 0.2 to 20% by weight of the following compound [A], consisting of the following units [B], and having the following physical properties [C] as a sheath component; A thermoplastic polymer having a temperature of 150°C or higher is used as a core component, and the weight ratio of the sheath component and the core component is 20:80 to 8.
It is a core-sheath type composite fiber with a ratio of 0:20. [A] A compound in which a group having a polyalkylene oxide chain is bonded to a polyalkylene polyamine skeleton, and has an HLB in the range of 6.0 to 16.0, an average molecular weight of 10,000 or more, and an amine value 500 or less. [B] Consisting of acid units and glycol units, the proportion of terephthalic acid units in the acid units is 40 mol% or more,
The proportion of isophthalic acid units is 20 mol% or more, and the proportion of ethylene glycol units in the glycol units is 75 mol% or more. [C] It is an amorphous polymer having a secondary transition point temperature of 50 to 90°C and a heat of crystal fusion of substantially 0. To explain the present invention more specifically, the compound used in the present invention in which a group having a polyalkylene oxide chain is bonded to a polyalkylene polyamine skeleton (hereinafter abbreviated as an N-POA compound) is known. For example, JP-A-58-80391 describes that the same compound can be used as a dispersant for coal slurry. [0013] The N-POA compound can be produced according to a general method for producing surfactants. For example, it can be obtained by blowing alkylene oxide gas into a heated polyalkylene polyamine skeleton compound containing an alkali catalyst such as caustic soda. Further, the polyalkylene polyamine compound serving as the skeleton can be obtained by reacting alkylene polyamines or alkylene polyamines with a compound such as urea. Therefore, the polyalkylene polyamine skeleton compound may contain groups other than alkylene groups, amino groups, and imino groups, such as carbonyl groups. [0014] It is preferable that the N-POA compound has substantially no reactivity with the polyester constituting the sheath component described below. Here, "having substantially no reactivity" means that it is not copolymerized with the polyester to a large extent. If the N-POA compound reacts with the polyester, spinnability becomes poor, which is not preferable. In other words, the degree of polymerization of polyester is lowered, and the melt viscosity during spinning is extremely reduced, resulting in unstable spinning properties and cross-sectional abnormalities.As a result, single yarn breakage and yarn breakage occur frequently, and continuous operation is interrupted. becomes difficult. The group having a polyalkylene oxide chain is preferably bonded to the nitrogen atom of the polyalkylene polyamine skeleton. Therefore, the N-POA compound used in the present invention includes cases in which substantially all of the hydrogen atoms of an amino group or an imino group are substituted with a group having a polyalkylene oxide chain. [0016] The N-POA compound has a molecular weight of 10
,000 or more, preferably 10
,000 or more and 100,000 or less. If the molecular weight is too low, the reactivity with the polyester sheath component will increase, causing the above-mentioned problems. Furthermore, if the molecular weight is too low, even if it does not react with the polyester, the compatibility will be poor and the spinnability during spinning will be poor, resulting in frequent single yarn breakage and yarn breakage. Of course, two or more types of N-POA compounds having different molecular weights, amine values, HLB values, etc. may be used in combination. A preferred structure of the N-POA compound is as follows:
It is a polymer in which oxyethylene units and oxypropylene units are randomly or block-copolymerized on an amine moiety, that is, an amino group or an imino group. An example of a structural formula is shown below. embedded image Here, R↓1 to R↓7 are a group having a polyalkylene oxide chain or a hydrogen atom. However, regarding R↓3, as is clear from equation (1) above, [n
]×[x] numbers exist, but these do not need to be the same. Similarly, R↓2, R↓4, R↓5
Also, [x] of each exists in one molecule, but these R↓2, R↓4, and R↓5 do not need to be the same. n of the polyamine molecular chain forming the skeleton is preferably 0 to 10, particularly preferably 0 to 5. If n is too large, the original effect of the polyester as a kneading agent for imparting water absorption properties will be insufficient. Also, x is 1
-20, especially 1-5 are preferred. If x becomes too large, the fibers are likely to be colored during spinning. [0018] It is necessary that an oxyethylene unit and an oxypropylene unit exist in the group having a polyalkylene oxide chain of R↓1 to R↓7 (however, an oxyethylene unit and an oxypropylene unit must be present in the same group). It is not necessary that propylene units coexist, i.e. only oxyethylene units may be present in some groups with polyalkylene oxide chains and only oxypropylene units in other groups with polyalkylene oxide chains. good)
Depending on the composition ratio of oxyethylene units and oxypropylene units, hydrophilicity may decrease, so it is preferable that oxyethylene units be the main component within a range that does not impede the object of the present invention. As a guideline for determining the appropriate range, it is best to use the HLB value. A more preferable group having a polyalkylene oxide chain is the structure shown in Formula 2 below, in which oxypropylene units (PO) are connected in a block form from the N atom, and further oxyethylene units (EO) are connected in a block form. ##STR2## The HLB value is a method to express the balance between hydrophilic groups and lipophilic groups in a surfactant.
Hydrophile Lipop announced by fin
hile Balance, but the HLB value is H
It is determined by LB value=20×M↓H/M. (M: molecular weight of surfactant, M↓H: molecular weight of hydrophilic group part) When the amount of hydrophilic groups in the molecule is 0%, HLB = 0, and when it is 100%, HLB = 20. When there are equal amounts of oil bases, HLB=10. In the case of the N-POA compound of the present invention, an oxyethylene unit was used as a lipophilic group as a hydrophilic group, and a polyoxypropylene unit was used as a standard for calculating the HLB value. HLB excluding the polyalkylene polyamine part of the skeleton etc.
Find the value. H of the N-POA compound used in the present invention
The range of LB value is 6.0 to 16.0. HLB value is 1
If it is higher than 6.0, the initial water absorbing performance after adding the N-POA compound to the binder polyester and forming it into fibers will be sufficiently developed, but the durability will be insufficient. In particular, the washing durability becomes insufficient and the water absorption performance after washing decreases. This is because the hydrophilic element of the N-POA compound becomes too strong, and the N-POA compound dispersed in the binder polyester is eluted during washing, resulting in a decrease in the water absorption performance of the fiber. It is thought that this is to put it away. On the other hand, if the HLB value is lower than 6.0, the hydrophobic element of the N-POA compound becomes too strong, so that it is not at a satisfactory level to impart the original water absorption performance to polyester. I can't reach it. The terminal of the group having a polyalkylene oxide chain may be a hydroxyl group, a non-ester-forming organic group, or an ether bond, an ester bond,
It may be bonded to other ester-forming organic groups through carbonate bonds or the like. Of course, as mentioned above, it is preferable that it is not copolymerized with polyester, but
Copolymerization may be carried out to the extent that the performance of the polyester is not significantly deteriorated, and from this, the terminal may be an ester-forming organic group. Further, atoms other than ethylene oxide units and propylene oxide units may be present within the group or at the base of the group. [0023] Furthermore, it is not necessary that groups having a polyalkylene oxide chain be bonded to all the amino groups and imino groups of the polyalkylene polyamine skeleton, and even if unreacted free amino groups and imino groups are present, I don't mind. However, the presence of too many free amino groups and imino groups is undesirable because it becomes highly toxic to the human body. In particular, when an N-POA compound is added to the fiber and the fiber is used for purposes such as direct contact with the human skin, care must be taken because skin damage may occur. From this point of view, the amino value of the N-POA compound of the present invention must be 500 or less. Preferably it is 100 or less. Note that the amino value is the number of milligrams calculated by converting the amount of acid required to neutralize 1 g of a compound into KOH. [0024] The polyalkylene polyamine structure constituting the skeleton of the N-POA compound has a plurality of alkylene groups and a plurality of nitrogen atoms. Alkylene groups are common. If the skeleton has only one alkylene group or only one amino group or imino group, the N-POA compound will have a low affinity with the polyester, and the object of the present invention will be not achieved. [0025] The reason why the N-POA compound used in the present invention is extremely excellent in imparting durable hydrophilicity to heat-fused polyester composite fibers is not necessarily clear, but the reason why the N-POA compound used in the present invention is extremely excellent in imparting durable hydrophilicity to heat-fused polyester composite fibers is not necessarily clear. It has excellent hydrophilicity, the ethylene oxide unit in the side chain has excellent hydrophilicity (wettability), and the propylene oxide unit in the side chain has a control function that balances the elution resistance and hydrophilicity of N-POA. As a result, it is believed that it has good water wettability and is extremely durable. This means that in the above general formula (1), a propylene oxide unit is first added as a side chain to the polyamine skeleton, and an ethylene oxide unit is added to the end of the side chain.
-The above prediction is also supported by the fact that it is the most preferred as a POA compound. The content of the N-POA compound described so far in the polyester polymer constituting the sheath component is 0.
It ranges from 2% to 20% by weight. If it is less than 0.2% by weight, the desired water absorbency is insufficient. If it exceeds 20% by weight, spinnability will be poor. Further, it may contain an oxidized spinning agent. In particular, when composite spinning is performed using a high melting point polymer such as polyethylene terephthalate as the core component, the spinning temperature becomes high and the polyoxyalkylene glycol portion is prone to oxidative decomposition and thermal decomposition. It is effective to add a dirt phenol type antioxidant to form fibers. Next, the polyester used for the sheath component will be specifically explained. As a polymer constituent unit, the total acid component (if it contains an oxy acid, half of it is the acid component, 2
Copolymerization mol% in 1/2 of the diol component)
terephthalic acid is 40 mol% or more, isophthalic acid is 20 mol% or more, ethylene glycol is 75 mol% or more as mol% of all glycol units, and has a secondary transition temperature of 50°C to 90°C, Preferably, it is an amorphous copolyester having a heat of crystal fusion of substantially 0 cal/g. More preferably, as the amorphous copolymerized polyester component, terephthalic acid (TA) is 50 mol % or more and isophthalic acid is 3 mol % or more based on the copolymerized mol % of the total acid components.
It is desirable that the content of ethylene glycol is 0 mol % or more, 80 mol % or more of ethylene glycol, and the secondary transition temperature is 60 to 90°C. If the TA content is less than 40 mol%, the fiber quality and processability are not good, and the cost is also not appropriate. In addition, if the copolymerization amount of isophthalic acid is less than 20 mol%, not only the peel strength during adhesion will decrease, but also the low temperature adhesive property, which is a feature of the present invention at an adhesive processing temperature of 200°C or less, will decrease. Undesirable. On the other hand, if it exceeds 60 mol %, it is unsuitable because the process efficiency during fiber production decreases. Further, if the proportion of ethylene glycol is less than 75 mol %, the physical properties are unfavorable, the quality of the fiber and processability are lowered, and the fiber is not suitable in terms of cost. Furthermore, in the copolymerized polyester of the present invention, in addition to the above copolymerized components, copolymerized components A and B satisfying the following ( ) and ( ) can be used as melting point regulators. 0≦A+B≦25
・・・・・・
・( ) 0≦B↓W≦25

・・・・・・( ) [Here A; Terephthalic acid,
Aromatic copolymerization component B other than isophthalic acid; aliphatic and/or alicyclic copolymerization component other than ethylene glycol The formula ( ) indicates the copolymerization mol% with respect to the total acid component, and the formula (
) is the B component raw material [COOH] and/or [O
The weight % based on the copolymerized polyester produced in the case of H] type is shown. [0030] As the copolymerization component A, various aromatic dicarboxylic acids, oxyacids and diols are used, and those having one or two aromatic nuclei are particularly used. Examples of A include phthalic acid, methylterephthalic acid, oxybenzoic acid, oxyethoxybenzoic acid, diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid, naphthadicarboxylic acid, bisphenol A, p-xylylene glycol, and the like. [0031] Specific examples of the above copolymer component B include:
When the adhesive treatment temperature for fibers or nonwoven fabrics is 150°C or lower, in order to appropriately adjust the polymer fluidity of the adhesive fibers, a linear molecular structure with high molecular mobility and no bulky chains is used. Adipic acid, sebacic acid,
Pentamethylene glycol, diethylene glycol, triethylene glycol and the like are preferred. In addition, the heat resistance of the fiber or nonwoven fabric is increased, and the adhesive treatment temperature is 150~150℃.
In the case of a relatively high temperature of 200°C, polymers with bulky side chains are used to suppress the fluidity of the polymer at temperatures below 150°C and to optimally adjust the fluidity of the polymer at a predetermined temperature of 150 to 200°C. Depending on the purpose, components with low molecular mobility at low temperatures such as cyclohexanedimethanol, 1,2-propylene glycol, neopentyl glycol, etc.
It is used in a range of mol % or less, preferably 15 mol % or less. If it exceeds 25 mol %, processability tends to deteriorate, which is undesirable from the viewpoint of ensuring high processability. The type of copolymerization component to be selected and the mol% of the copolymerization amount vary depending on the intended fiber or the intended use of the nonwoven fabric sheet. In addition, when the ester-forming group of component B is [COOH] and/or [OH] group, the weight % based on the copolymerized polyester produced is 25
Up to 15% by weight is used, preferably up to 15% by weight. If the amount of copolymerization exceeds 25% by weight, the polymer will become soft and the fiber manufacturing process will be deteriorated, which is not preferable. In the present invention, if the total amount of component A and component B exceeds 25 mol %, not only the efficiency of the fiber manufacturing process deteriorates but also it is unfavorable in terms of cost. The copolymerized polyester used in the fibers of the present invention must satisfy the above-mentioned compositional conditions of terephthalic acid, isophthalic acid, and ethylene glycol, and must also meet the requirements for fiber production stability and adhesion at a commercial production level. In order to ensure quality as a fiber, the secondary transition point and heat of crystal fusion must be appropriate. That is, the copolymerized polyester constituting the sheath component of the present invention is an amorphous polymer having a heat of crystal fusion (ΔH) of substantially 0. When a polymer becomes one in which ΔH can be measured, its quality as an adhesive fiber deteriorates, and in particular, the deterioration in peel strength becomes remarkable. In the present invention, △H refers to a sample taken from a molten polymer in the form of fine fibers or thin film pieces, cooled, and left at room temperature for 3 days or more. This value is determined from the area of the endothermic peak when the crystalline region melts when the temperature is increased at a rate of Substantially no endothermic peaks occur. Therefore, ΔH is substantially 0. If the endothermic peak is so broad that it cannot be clearly determined, it is safe to assume that there is substantially no endothermic peak and that ΔH is 0. Further, the ΔH value did not vary depending on the intrinsic viscosity if the polymer composition was the same. If there is a value of ΔH based on crystals, the peel strength as an adhesive fiber will actually decrease, which is undesirable. Furthermore, since the polymer used in the present invention is substantially an amorphous polymer, there is no problem of morphological change due to fiber shrinkage due to crystallization during the heat treatment process in the adhesive treatment process. Moreover, since preheating treatment can be performed in the pre-processing process up to the bonding process, product management is not only easy, but it is also possible to operate with good thermal efficiency, ensuring that the product has good quality such as dimensional stability. Not only is this advantageous, but it is also advantageous in terms of operating costs. Further, the copolyester used in the present invention must have a secondary transition point within the range of 50°C to 90°C. Preferably, the temperature range is from 60°C to 90°C. 50
If the temperature is less than 0.degree. C., not only will the fiber manufacturing process become extremely difficult, but the morphological stability of the product will also decrease. Specifically, with regard to process efficiency, it becomes difficult to cut the polymer into pellets during polymer production. Furthermore, even though the miscut rate is high, even if fibers are produced by spinning pelletized pellets, sticking, fusion, or breakage between single yarns frequently occurs during spinning. Further, during subsequent stretching, crimping, cutting, etc., adhesion and fusion occur, making it impossible to obtain good fibers. However, it is of course possible to omit the drawing step if the spun yarn state sufficiently satisfies the desired properties of the adhesive fiber. When the secondary transition point is 50° C. or higher, by appropriately setting the pellet drying temperature, stretching temperature, etc., stable production for a long period of time that satisfies commercial productivity and operational productivity becomes possible. Even if the secondary transition point exceeds 90° C., the processability in fiber production does not particularly deteriorate, but the quality performance as an adhesive fiber deteriorates. In particular, it is not preferable because the low temperature adhesion performance at temperatures below 150° C. deteriorates significantly. In particular, in the present invention, an N-OPA compound is contained in the above-mentioned copolymerized polyester, but this tends to substantially lower the apparent secondary transition point of the polymer. It was discovered that the secondary transition point of the polymer should be kept at 50° C. or higher to avoid the phenomenon of adhesion between single fibers and adhesion between single fibers during the stretching process during the fiberization process. The second-order transition point mentioned here is determined by measuring the temperature distribution and tan δ using a "Vibrone Direct Reading Dynamic Viscoelasticity Meter Model DDV-" manufactured by Toyo Baldwin Co., Ltd., and based on the tan δ measurement value. The dynamic loss modulus (E″) was determined, and the temperature at which the E″ value reached the maximum was defined as the second-order transition point. The measurement conditions at this time were a driving frequency of 110 cps, and a temperature increase rate of 1° C./min starting from room temperature. To prepare the measurement sample, prepare a sample with a width of 5 mm and a length of 20 mm from the melted polymer.
A thin film with a thickness of 0.2 mm and a thickness of 0.2 mm was prepared, and immediately after the film was formed, it was cooled and left at room temperature for 3 days or more, and measurements were taken. At this time, if there is unevenness in the thickness of the film, the measured values will vary slightly, so we measured each of the five measurement films that were adjusted separately, and the average value of the five measured values was taken as the secondary transition point. Established. Furthermore, E'' did not vary depending on the size of the intrinsic viscosity as long as the polymer composition was the same. A small amount of additives, such as titanium oxide, etc., were added to the copolyester constituting the sheath component. The fiber of the present invention may contain an eraser, an antioxidant, a fluorescent brightener, a stabilizer, or an ultraviolet absorber. , is a composite fiber with a core component of other melt-spun polymers.In order to maintain its purpose as a heat-adhesive and durable hydrophilic nonwoven fabric and to maintain good fiber processability, it is best to have a composite fiber structure. As the core component, a thermoplastic polymer having a melting point of 150° C. or higher is used, examples of which include polyethylene terephthalate, polybutylene terephthalate, nylon-6, nylon-6,6, polypropylene, etc. There are crystalline melt-spun polymers that can be spun.In order to achieve a sufficient purpose as an adhesive fiber, it is necessary to increase the ratio of the N-OPA compound-containing copolyester component to the total circumference of the composite fiber cross-section, that is, the cross-sectional circumference of the fiber. The ratio is preferably 50% or more.In this case, it goes without saying that if the morphological stability of the adhesive fiber is important, it is necessary to use a thermoplastic polymer with a melting point higher than the adhesive processing temperature as the core component. [0040] Specific examples of the cross-sectional shapes of the core-sheath type composite fiber of the present invention as composite forms are explained with figures. A core-sheath type composite fiber with a core component having an irregular shape as shown in Fig. 5, a multi-core sheath-core type conjugate fiber as shown in Fig. 4, an eccentric core-sheath type conjugate fiber as shown in Fig. 6, a core-sheath type conjugate fiber with an irregular cross section as shown in Figs. 7 and 10. Composite fiber, laminated composite fiber as shown in Fig. 8, multilayer laminated composite fiber as shown in Fig. 9, Fig. 1
Also included are composite fibers of a modified multi-layer bonding type such as No. 1. Component (a) in FIGS. 1 to 11 is a copolymerized polyester containing an N-POA compound, that is, a sheath component, and component (b) is a thermoplastic polymer having a melting point of 150° C. or higher, that is, a core component. It is desirable that component (a) polymer accounts for about 50% or more of the fiber cross-sectional circumference. If it is less than 50%, it is difficult to obtain durable hydrophilic and heat-adhesive fibers which are the object of the present invention. The composite ratio of the sheath component and the core component must be in the range of 80:20 to 20:80% by weight. If the content of the sheath component is less than 20% by weight, it is not preferable because the good hydrophilicity and good thermal adhesion that are the objectives of the present invention will be insufficient. Moreover, if it exceeds 80% by weight, process properties such as spinnability and stretchability will deteriorate, and the A maximum will decrease, which is not preferable. The fibers of the present invention may be used as a fusion-treated fiber aggregate consisting only of composite fibers of copolyester containing an N-POA compound and other polymers.
It may also be used as a mixed and fused fiber aggregate with other fibers containing 0% by weight or more. Fiber aggregates cut into pieces of 20 to 100 mm can be used as dry nonwoven fabric binders, and
Those cut into pieces of ~10 mm are suitable as a wet nonwoven fabric binder, and can provide a nonwoven fabric with high strength, durable hydrophilicity, and moisture and heat resistance. Among these, in the case of polyester containing terephthalic acid as a component, such as polyethylene terephthalate or polybutylene terephthalate, as a mixed fiber, the adhesion is good not only between the bonding fibers but also with the terephthalic acid-based polyester, resulting in a highly strong nonwoven fabric. It can be done. Conventionally, there were no fibers that adhered to terephthalic acid polyester, which was a big problem, but the present invention has made it possible to produce a good polyester nonwoven fabric and also at a low cost. Further, when a hydrophilic material such as wood pulp, rayon, vinylon, etc. is used as the mixed fiber, the hydrophilicity is not only not inhibited but also more actively exhibited. The fibers of the present invention are useful in a wide variety of nonwoven fabrics for various uses, but a particularly significant feature is that they exhibit remarkable effects in wet-laid nonwoven fabrics. As a specific application, for example, sanitary materials requiring hydrophilicity are suitable. [0044] Furthermore, the N-OPA compound used in the present invention is highly safe; for example, sodium alkylbenzenesulfonate (ABS) is a typical anionic surfactant that is commonly used. When comparing fish toxicity data, ABS compounds have an LC50 of 5.
While it is 0 ppm or less, the N-OPA compound of the present invention has a concentration of 50,000 ppm or more, which is much safer. Moreover, as mentioned above, the N-OPA compound is
When kneaded into copolymerized polyester, we immersed the fibers in water and examined the elution properties of the kneading agent, and found that while ABS compounds elute nearly 30% from the fibers in one month,
It can be confirmed that the content of N-OPA-based compounds is 10% or less, and the elution property is also quite low, which is convenient. Evaluation of durable hydrophilicity as referred to in the present invention was carried out by the following two methods: water permeability and water permeability. Water permeability is measured by adding one drop of water from a buret to an evaluation paper prepared under specified conditions, as shown in Figure 12. Judgment was made with the naked eye. Regarding water permeability, as shown in FIG. 13, an evaluation sheet for measurement was placed on the cotton linter pulp, one drop of water was dropped from the burette in the same manner, and the water droplets that fell onto the paper were collected. The time until the condition disappeared was measured visually. Papers with a basis weight of 20 to 80 g/m↑2 were evaluated using two methods: water permeability and water permeability. [0047] Regarding durability, the test paper was
Repeat washing 10 times according to method 0217-103,
Performance was evaluated by measuring water permeability and water permeability after 10 times. In addition, the intrinsic viscosity [η] in the examples is
The intrinsic viscosity (dl
/g). [Examples] Next, the present invention will be explained with reference to Examples, but the present invention is not limited to these in any way. Hereinafter, terephthalic acid will be abbreviated as TA, isophthalic acid as IPA, and ethylene glycol as EG. [Example 1] 280℃ using a polycondensation reactor in a conventional manner
A polycondensation reaction was carried out with 60 moles of TA, isophthalic acid (
A copolymerized polyester consisting of 40 moles of IPA), 90 moles of ethylene glycol (EG), and 10 moles of diethylene glycol was produced, and then extruded into water in the form of a sheet from the bottom of the polymerization vessel, and cut into pellets using a sheet cutter. The extrusion and cutting conditions were good, and pellets with a good shape were obtained. The physical properties of copolymerized polyester are [η
]0.69, △H 0cal/g, secondary transition point 70
It was warm at ℃. When the obtained pellets were dried at 60° C. in a vacuum dryer, no agglutination was observed. [0049] Next, the copolymerized polyester is melted,
Into the molten polymer, an N-polyoxyalkylene polyalkylene polyamine compound represented by the following formula (2),
A predetermined amount of a product with an HLB of 12.0, an average molecular weight of about 50,000, and an amine value of 4.5 plus a small amount of a hindered phenol antioxidant was added, and then uniformly mixed using a static mixer. Using the mixed polymer stream as a sheath component and polyethylene terephthalate having [η] of 0.67 as a core component, core-sheath composite spinning having the cross section shown in FIG. 1 was carried out at a core/sheath weight ratio of 50/50. Spinning head temperature 2
It was extruded at 90°C and wound up at 1000 m/min. The wound fibers had no adhesion between single fibers or fiber bundles, and could be stably spun for a long period of time. The pellet transportability of the sheath component in the extruder was good and there were no problems. This spun yarn was stretched 4.2 times in a water bath at 70°C, and then expanded and contracted by 8% at 75°C in a water bath, with a fineness of 2.0 dr and a strength of 3.5 g.
/d, and a fiber with an elongation of 43% was obtained. After mixing 70 parts by weight of the obtained drawn yarn cut into fiber lengths of 5 mm and 30 parts by weight of polyethylene terephthalate fibers (2 dr x 5 mm), the mixture was mixed in a square tapie paper machine to produce fiber paper. . After that, it was dried for 1 minute at 120°C on a Yankee dryer-type floe board heated cylinder, and then glued and the basis weight was 20g/m↑2, 40g/m↑2, 8
Handmade paper of 0g/m↑2 was produced. In either case, the paper could be easily made without any problems with adhesion, and it maintained sufficient strength to withstand practical use. [0051] Subsequently, hydrophilicity evaluation was carried out, and it was found that
The results of water permeability and water permeability are shown in Table 1, and Comparative Example 1
It was found that it not only had excellent initial performance but also excellent durable hydrophilicity. In addition, the above prepared paper for hydrophilic performance evaluation was immersed in pure water (bath ratio 1:50) for one month, and the amount of N-OPA compound kneaded into the fiber eluted into the water was calculated as Total Organic Carbon.
When measured using an Analyzer (TOC-500 manufactured by Shimadzu Corporation), it was confirmed that only about 5% of the N-OPA compound kneaded into the fibers was eluted, which was found to be at a level that poses no problem. Ta. [Comparative Example 1] The only difference from Example 1 was that it did not contain a hydrophilic agent. The sheath component was a copolymerized polyester, while the core was polyethylene terephthalate with [η ] 0.67. Core/sheath composite spinning with the cross section shown in FIG. 1 was carried out using a core/sheath weight ratio of 50/50. Spinning head temperature 290
It was extruded at ℃ and wound at 1000 m/min. The obtained spun yarn was drawn in the same manner as in Example 1, and then a test paper was produced under the same conditions. Subsequently, hydrophilicity was evaluated, and the results shown in Table 1 were obtained, indicating that it was unsatisfactory. [Table 1] [0055] Note) Washing according to JIS L0217-10
Implemented in accordance with 3 laws. Add and dissolve 2 g of synthetic laundry detergent to 1 liter of water at a liquid temperature of 40°C to prepare a washing liquid. A sample and, if necessary, a load cloth are added to the washing liquid at a bath ratio of 1:30, and operation is started. After processing for 5 minutes,
Stop the operation, dehydrate the sample and load cloth in a dehydrator, then change the washing solution to fresh water at room temperature, rinse for 2 minutes with the same bath ratio, dehydrate, rinse again for 2 minutes, and air dry. let The above operation was repeated 10 times, and a measurement sample was obtained after 10 times. [Examples 2 to 17] Using a copolymerized polyester having the same polymer composition as in Example 1, tests were conducted under the conditions listed in Table 2, and the results are shown. In Examples 2 and 3, the amount of the hydrophilic agent added was changed. In Examples 4 and 5, the molecular structure is the same as that of formula (2) as a hydrophilic agent, but HLB
Different values were used. Example 4 has HLB=8.0
In Example 5, one with HLB=15.0 was used. In Example 6, a hydrophilic agent having the same molecular structure as formula (2) but with an average molecular weight of 20,000 was used. Examples 7 and 8 were tested by changing the core/sheath composite ratio. Examples 9 to 13 were tested by changing the fiber cross-sectional shape. Example 14 was conducted using polybutylene terephthalate as the core component polymer, and Example 15 was conducted using nylon 6. Examples 16 and 17 were carried out by changing the paper-making conditions, that is, the mixing ratio of polyethylene terephthalate fiber as the mixed fiber. All of them have good fiberization process properties, have a large breaking length, which is a measure of the strength of the test paper, and have a hydrophilic property of 1 after washing.
It was found that a good level was maintained even after 0 treatments. Furthermore, it was confirmed that the dissolution properties were not at any level that would pose a problem. [Example 18] As an additive, the molecular structure is (
The same method as in Example 1 was carried out except that the formula 3) was used. ##STR4## In the formula (3), R↓1 to R↓7 are PO and EO
It is a random copolymer with an HLB of 12.0 and an average molecular weight of about 50,000. As a result, the fiberization process was successful, and durable fibers with good water absorption properties were obtained. [Examples 19 to 21] In Example 19, a polycondensation reaction was carried out at 280°C in a conventional manner using a polycondensation reactor, and a copolymerized polyester consisting of 70 moles of TA, 30 moles of IPA, 95 moles of EG, and 5 moles of diethylene glycol was obtained. In Example 20, a copolyester consisting of 50 moles of TA, 50 moles of IPA, and 100 moles of EG was produced by the same method as in Example 1, and in Example 21, a copolyester consisting of TA6
5 mol, IPA 30 mol, sebacic acid 5 mol, EG10
A 0 mol polymer was prepared, and then a conjugate fiber to which a hydrophilizing agent was added was prepared in the same manner as in Example 1. Thereafter, a test paper was prepared in exactly the same manner as in Example 1. The paper had sufficient tearing strength and good hydrophilicity. Furthermore, it was confirmed that the dissolution of the hydrophilic agent kneaded into the fibers was not at a level that would cause any problems. [Comparative Examples 2 to 3] In Comparative Example 2, the same N-OPA compound as in formula (2) was used, and a small amount of hindered phenolic antioxidant was added. This is a case where the experiment was carried out under the same conditions as in Example 1 except that N-OPA was kneaded into the copolyester in an amount of 0.1 wt%. The water absorption level was lower than that of Example 1. Comparative Example 3 is a case in which the compound was added to the amorphous copolymerized polyester of the sheath component at a concentration of 25 wt %, and the other conditions were the same as in Example 1. However, the viscosity during spinning was severely reduced and stable spinning could not be achieved. [Comparative Example 4] An additive having the same structure as the formula (2) and having a molecular weight of about 8,000 was used, and the other methods were the same as in Example 1. However, the viscosity during spinning was severely reduced, screws fell off, and single fiber breakage and yarn breakage occurred frequently, making stable spinning impossible. [Comparative Example 5] An additive having the same structure as that of formula (2) but with HLB=5.0, that is, one rich in PO segment of a hydrophobic group, was used, and the other additives were those of Example 1. It was carried out in the same manner as. Although the fiberization processability was good, the water absorption performance level was insufficient. [Comparative Examples 6 to 7] Comparative Example 6 was the same method as Example 1 except that core/sheath composite spinning with the cross section shown in FIG. 1 was carried out at a core/sheath ratio of 10/90 by weight. It was carried out by The composite ratio was unstable, single thread breakage occurred frequently, and evaluation samples could not be obtained. In Comparative Example 7, a copolymerized polyester was obtained in the same manner as in Example 1, and then fiberized in the same manner as in Example 1 except that the composite ratio was changed to a core/sheath = 90/10 weight ratio. was created. The paper strength and hydrophilicity were insufficient. [Comparative Example 8] A polycondensation reaction was carried out by a conventional method, and a copolymer containing 80 mol of TA, 20 mol of IPA, and 100 mol of EG, [η] 0.76, △H 0.7 cal/g, and a secondary transition point of 76°C. Polymerized polyester was produced, the same amount of the hydrophilizing agent as in Example 1 was added, and the same amount was added as in Example 1, followed by spinning to obtain a spun yarn. Then, stretching and shrinking are performed to obtain a fineness of 2.0 dr, strength of 4.5 g/dr, and elongation of 30%.
fibers were obtained. The processability was good and there were no particular troubles, and no sticking between single fibers or between fiber bundles was observed. However, when a test paper was prepared in the same manner as in Example 1, the fresh water performance was good, but the tearing length was 0.1 km.
It was extremely low in strength. [Comparative Example 9] A polycondensation reaction was carried out by a conventional method, and 45 mol of TA, 25 mol of IPA, 100 mol of EG,
A copolymerized polyester consisting of 30 moles of sebacic acid was produced, extruded into water from the bottom of the polymerization vessel in the form of a strand, and cut using a strand cutter to obtain pellets having the physical properties shown in Table 2. However, due to the low secondary transition temperature of the polymer, the strands were soft and insertion into the cutter was quite difficult, and the cutter was often shut down due to accumulation of uncut strands and fusion of the polymer to the cutter. Therefore, the yield of pelletization was increased by extruding the strands into ice water at 0°C. When this pellet was dried at 45° C. in a vacuum dryer, a sticky lump formed, so drying was carried out at room temperature for a long time. Then, it was fed to an extruder, a hydrophilizing agent was added in the same manner as in Example 1, and composite spinning was performed at a spinning head temperature of 280°C at a speed of 1000 m/min. A lot of sticking occurred and it was not possible to obtain good fibers. [Table 2] [Table 3] [Table 4] [Example 22, Comparative Example 10] In the same manner as in Example 1, a copolyester containing an N-OPA compound was sheathed. , [η]0.67 polyethylene terephthalate core, core/sheath weight ratio 50/50
A polyester binder fiber with a fineness of 2.
Cut fibers with a fiber length of 5 mm were obtained at 0 dr. 70 parts by weight of cut fiber and hydrophilic rayon (PB150)
5) After mixing 30 parts by weight of cut fibers with a fineness of 1.5 dr and a fiber length of 5 mm, the mixture was mixed with a square tapie paper machine,
Fiber paper was produced. Thereafter, they were dried for 1 minute at 120° C. on a Yankee dryer-type floe plate thermal cylinder and adhered to produce hand towels with basis weights of 20 g/m↑2, 40 g/m↑2, and 80 g/m↑2. In either case, there were no problems with adhesion, the paper could be easily made, and it maintained sufficient strength to withstand practical use. As a comparative example, a binder fiber was produced that differed from the above binder fiber in that it did not contain the above hydrophilic agent, and was mixed with hydrophilized rayon in the same manner as in the above Example to obtain a test paper. When the hydrophilicity of these two papers was evaluated, the water permeability and water permeability results were shown in Table 5. In the case of this example, it had not only initial performance but also excellent durable hydrophilicity. You can see that Furthermore, Comparative Example 10 shows that even if the fibers to be mixed with the binder fibers are hydrophilic fibers, if the binder fibers are not hydrophilic, the hydrophilicity of the resulting paper is poor from the initial performance.

[Table 5] [Effects of the Invention] As described above, the present invention uses a copolymerized polyester having a specific polymer composition and polymer physical properties, and furthermore, contains a specific hydrophilic agent in the copolymerized polyester. Durable hydrophilic heat-fusible conjugate fibers and composite fibers, which have excellent durability and good hydrophilicity with little elution and excellent safety, and especially good heat-fusion bonding to polyester fibers. An object of the present invention is to provide a nonwoven fabric using some or all of the fibers.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the cross-sectional shape of a composite fiber of the present invention.

FIG. 2 is a diagram showing another example of the cross-sectional shape of the composite fiber of the present invention.

FIG. 3 is a diagram showing still another example of the cross-sectional shape of the composite fiber of the present invention.

FIG. 4 is a diagram showing another example of the cross-sectional shape of the composite fiber of the present invention.

FIG. 5 is a diagram showing an example of the cross-sectional shape of the composite fiber of the present invention.

FIG. 6 is a diagram showing another example of the cross-sectional shape of the composite fiber of the present invention.

FIG. 7 is a diagram showing another example of the cross-sectional shape of the composite fiber of the present invention.

FIG. 8 is a diagram showing another example of the cross-sectional shape of the composite fiber of the present invention.

FIG. 9 is a diagram showing another example of the cross-sectional shape of the composite fiber of the present invention.

FIG. 10 is a diagram showing another example of the cross-sectional shape of the composite fiber of the present invention.

FIG. 11 is a diagram showing another example of the cross-sectional shape of the composite fiber of the present invention.

FIG. 12 is a schematic diagram of an apparatus for measuring water permeability.

FIG. 13 is a schematic diagram of an apparatus for measuring water permeability.

[Explanation of symbols]

A: Sheath component made of amorphous polyester B: Melting point 150
Core component made of thermoplastic polymer with temperature above ℃

Claims (1)

[Claims] Claim 1: The sheath component is a polyester containing 0.2 to 20% by weight of the compound [A] below, consisting of the units [B] below, and having the physical property values of [C] below, and having a melting point of 150°C or higher. A core-sheath type composite fiber having a plastic polymer as a core component and having a weight ratio of the sheath component and the core component of 20:80 to 80:20. [A] A compound in which a group having a polyalkylene oxide chain is bonded to a polyalkylene polyamine skeleton, and has an HLB in the range of 6.0 to 16.0, an average molecular weight of 10,000 or more, and an amine value of 500 or less. a certain compound. [B] Consisting of acid units and glycol units, the proportion of terephthalic acid units in the acid units is 40 mol% or more,
The proportion of isophthalic acid units is 20 mol% or more, and the proportion of ethylene glycol units in the glycol units is 75 mol% or more. [C] It is an amorphous polymer having a secondary transition point temperature of 50 to 90°C and a heat of crystal fusion of substantially 0.