JPH04222221A - 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 and higher than that of the polyester of the sheath component 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 melting point of 90-200 deg.C, a heat of crystal melting of >=2.0cal/g and a shortest crystallization time of >=80sec. The sum of TA unit and isophthalic acid unit in the acid unit is >=60mol% and the sum of 1,6-hexanediol unit and 1,4-butanediol unit in the glycol unit is >=60mol%.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a heat-adhesive composite fiber having excellent hydrophilic properties, and moreover, when manufacturing a fiber aggregate using the fiber, there is no process trouble and the manufacturing process is smooth. It is about fibers that can
The purpose is to provide a polyester thermoadhesive conjugate fiber that does not cause any particular process troubles, has highly durable hydrophilic properties, and has no safety issues.

0002

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 heat-fusible fibers have been developed that use polyester as an adhesion partner. However, in order to bond polyester fibers, it is preferable to use polyester-based polymers as adhesive components due to the similarity in chemical structure and solubility parameters. It is preferable from the viewpoint of adhesive strength and process passability. In fact, many soft amorphous copolymer polyesters with low glass transition points have been proposed as solvent-soluble or hot-melt adhesives that use polyester as an adhesion partner.

However, when a soft amorphous copolymer polyester with a low glass transition point is used as an adhesive fiber, it passes through specific equipment and a specific thermal history in the fiber or nonwoven fabric manufacturing process. During the treatment process at a temperature above the softening point of the amorphous copolyester, the amorphous copolyester softens and fuses, making it impossible to make it into fibers.
Ordinary copolyesters for adhesives cannot be used at all.

For example, when extruding a molten polymer through a spinneret to form fibers and storing the fiber bundle in a can or winding it onto a bobbin, it is difficult to obtain spun fibers due to severe adhesion between single fibers or fiber bundles. becomes. Further on,
If stretching, crimping, cutting, etc. are performed, adhesion and fusion between single fibers will occur, making it impossible to obtain good fibers. In particular, when handling fiber bundles with a large total denier in order to increase production, the problems in the fiber manufacturing process become even more pronounced. Furthermore, even if fiberization is performed incompletely, for example, when converting it into a non-woven fabric, problems such as the generation of neps may result in poor card passage, and problems with adhesion occur during adhesion processing, making it impossible to convert into a non-woven fabric. . The process properties required for this spinning and the subsequent fiberization and nonwoven fabric manufacturing processes are extremely strict, and the molten polymer is taken out of the polymerization tank and is cut into pellets in the chipping process and the pellets are transferred to the spinning machine. Even if it passes the drying process without any trouble before being fed to a directly connected extruder, very little can be made into fibers or non-woven fabrics.

On the other hand, depending on the type of copolymerized polyester, if the amount of copolymerization is reduced and the degree of modification is lowered, it is possible to obtain a polymer that maintains a high level of crystallinity and has a fast crystallization rate. However, such fibers are made of polyesters such as polyethylene terephthalate (hereinafter abbreviated as PET) or polybutylene terephthalate (hereinafter abbreviated as PBT), which are currently commercially mass-produced. In general, the adhesiveness with fibers is low, so it cannot be used as an adhesive fiber.

[0007] On the other hand, there is also a need for the development of polyester heat-fusible fibers that can impart durable hydrophilic properties to the resulting polyester nonwoven fabric, but in reality this has not yet been developed. Particularly recently, we have been working in the field of sanitary materials such as baby diapers, diaper liners, and sanitary products, in the field of non-hygienic materials such as counter cloths for the restaurant industry, draining bags for kitchen utensil sinks, and in the field of base fabrics and fixing sheets for sip medicines.
Nonwoven fabrics have been widely used in the medical field, such as hospital surgical gowns and masks. Among these many nonwoven fabric products, baby diapers and sanitary products in particular are required to have hydrophilic properties that are more durable than conventional products. However, most of the products to date have been surface treated with hydrophilic oils, that is, post-processing methods, 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.

[0008] Among these, wet-type nonwoven fabric applications for the surface material of diapers and sanitary pads always go through a papermaking process in water during the manufacturing process, so the method of coating the fiber surface with a hydrophilic agent 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.

[0009] Recently, an attempt has been proposed to impart durable liquid absorbing and liquid retaining properties by kneading polyoxyalkylene glycol, which is a hydrophilic agent, and a metal sulfonic acid derivative into modified polyester. However, sulfonic acid metal derivatives are compounds that are generally harmful to the human body, and when nonwoven fabrics for wet wipes made of modified polyester fibers containing such compounds are immersed in a wetting agent such as hydrous alcohol, they may enter the fibers. There was a problem that a large amount of kneaded sulfonic acid metal derivatives etc. were eluted. When the nonwoven fabric is used, it contaminates the object to be wiped, and when used on the body, hygiene and safety problems arise.

0010

[Problems to be Solved by the Invention] An object of the present invention is to provide a fiber that has excellent adhesion to polyester and is easy to process in the production of fibers and nonwoven fabrics, and which is suitable for both dry and wet nonwoven fabrics. An 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.

Another object of the present invention is to provide a durable hydrophilic heat-fusible fiber in which a hydrophilic agent is less eluted from the fiber and the eluted material does not pose a safety problem to the human body. Another object of the present invention is that when a nonwoven fabric or sheet is obtained from heat-fusible fibers using a hydrophilic material such as wood pulp, viscose rayon, or vinylon, the heat-fusible fibers are hydrophilic. without inhibiting the hydrophilicity of the material.
An object of the present invention is to provide a heat-fusible fiber having excellent hydrophilic durability and capable of exhibiting hydrophilic properties.

0012

[Means for Solving the Problems] The fiber of the present invention contains a compound in which a group having a polyalkylene oxide chain is bonded to a polyalkylene polyamine skeleton in a predetermined amount, and which satisfies specific conditions. Composite fibers are produced by containing and dispersing a specific polymer in a crystalline polyester having specific polymer physical properties, using the dispersion as a sheath component, and a thermoplastic polymer with a melting point of 150°C or higher as a core component. It is a heat-adhesive composite fiber having durable hydrophilic properties.

That is, the present invention uses a polyester as a sheath component containing 0.2 to 20% by weight of the compound [A] below, consisting of units [B] below, and having the physical property values of [C] below; A thermoplastic polymer having a higher melting point than the polyester constituting the sheath component at 150°C or higher is used as the core component,
and the weight ratio of the sheath component and the core component is 20:80 to 80.
:20, which is a core-sheath type composite fiber.

[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 total amount of terephthalic acid units and isophthalic acid units occupying in the acid units is 60 mol% or more, and 1,6-hexanediol units and 1,6-hexanediol units occupying in the glycol units , 4-butanediol units in a total amount of 60 mol% or more. [C] Melting point is 90-200℃, heat of crystal fusion is 2.0
Cal/g or more, minimum crystallization time within 80 seconds.

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.

[0016] 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.

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, N used in the present invention
-POA compounds also include cases where substantially all of the hydrogen atoms of the amino group or imino group are substituted with a group having a polyalkylene oxide chain.

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] numbers of each exist 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.

[0021] 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 (E0) are connected in a block form.

[0022]

[Case 2]

HLB value is a method of expressing the balance between hydrophilic groups and lipophilic groups of surfactants, which was developed by Griff in 1940.
Hydrophile Lipoph announced by in
ileBalance, the HLB value is determined by HLB 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, when 100%, HL
When B=20 and there are equal amounts of hydrophilic and lipophilic groups, 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. The HLB value is determined by excluding the polyalkylene polyamine portion of the skeleton.

H of the N-POA compound used in the present invention
The LB value ranges from 6.0 to 16.0. HLB value is 1
If the value is higher than 6.0, N- will be added to the polyester.
After adding a POA compound and forming fibers, the initial water absorption performance is sufficiently developed, but the durability becomes insufficient. In particular, the durability after washing 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 when it is washed, the N-POA compound dispersed in the polyester is eluted, resulting in a decrease in the water absorption performance of the fiber. It is thought that this is because of this. 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 it is not satisfactory for imparting the original water absorption performance to polyester fiber. I can't reach the level.

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 it may be copolymerized to the extent that it does not significantly reduce the performance of polyester. There may be. Further, atoms other than ethylene oxide units and propylene oxide units may be present within the group or at the base of the group.

[0026] Furthermore, it is not necessary that groups having a polyalkylene oxide chain are 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 fibers and the fibers are 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 amine value of the N-POA compound of the present invention must be 500 or less. Preferably it is 100 or less. Note that the amine value is the number of milligrams calculated by converting the amount of acid required to neutralize 1 g of a compound into KOH.

[0027] 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.

[0028] 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 polyalkylene polyamine skeleton has an affinity with polyester. The ethylene oxide unit in the side chain is hydrophilic (
It has excellent wettability) and the propylene oxide unit in the side chain is N.
- It has a control function that balances the elution resistance and hydrophilicity of POA, and as a result, it has good water wettability and is thought to be extremely durable. . This means that the general formula (
The above prediction is also supported by the fact that in 1), a compound in which 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 is the most preferable N-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. It may also contain an antioxidant. In particular, when composite spinning is performed using a polymer with a high melting point such as polyethylene terephthalate as the core component, the spinning temperature becomes high and the polyoxyalkylene glycol part is likely to undergo oxidative decomposition and thermal decomposition. It is effective to add a dophenol-based antioxidant to form fibers. It was found that process properties such as stretchability were poor.

Next, the polyester used for the sheath component will be specifically explained. As the polymer constituent unit, the acid unit is essentially a terephthalic acid (TA) unit alone or substantially composed of terephthalic acid and isophthalic acid (IPA) units,
That is, the total amount of terephthalic acid and isophthalic acid units is 60 mol% or more of the total acid units, and the glycol units are 1,
It consists of a polymer unit in which the total amount of 6-hexanediol (HD) units and 1,4-butanediol (BD) units is 60 mol% or more, the melting point is 90 to 200°C, and the heat of crystal fusion (ΔHu) is 2 cal/ g or more, the shortest crystallization time is 9
It is a crystalline polyester that can be used within 0 seconds.

[0031] This polyester is defined as the polymerization percentage (hereinafter, polymerization percentage is calculated based on the total acid component (if oxyacid is included, one-half is considered to be the acid component and one-half is the diol component) of the produced polyester. It is preferable to use TA in an amount of 50 mol % or more (expressed in mol % based on the total acid components). T.A.
If it is less than 50 mol%, the quality of the fiber and processability are not good, and the cost is also not appropriate. And TA and IPA
As mentioned above, the total amount must be 60 mol % or more, and if it is less than 60 mol %, the quality of the fiber and processability will particularly deteriorate. In terms of economy, the component amounts of TA and IPA are preferably 80 mol% or more.

On the other hand, if the IPA component increases too much, the degree of crystallinity will decrease and at the same time the crystallization speed will also become extremely slow, which is not preferable because troubles in the process of manufacturing adhesive fibers will frequently occur. . However, in order to maintain the above-mentioned polymer physical properties (crystalline heat of fusion, shortest crystallization time), appropriate IPA copolymerization is preferred.

Further, the polyester used has a total content of BD and HD of 60 mol % or more, preferably 70 mol % or more, and more preferably 80 mol % or more. 60
If the amount is less than mol %, the physical properties are unfavorable, the quality of the fiber and processability are reduced, and the cost is also not appropriate. In particular, it is preferable that BD or HD alone is 60 mol % or more, and either BD or HD may be 0 mol %. Although the use of IPA is very convenient from the standpoint of economy, polymerization equipment, and production efficiency, IPA tends to reduce the crystallinity of the polymer because it has an asymmetric molecular structure. Therefore, in order to maintain the physical properties of the polymer of the present invention for producing the target adhesive fibers, that is, the heat of crystal fusion and the shortest crystallization time, it is necessary to
The glycol units that can compensate for the decrease in crystallinity of A need to be mainly HD and BD.

[0034] In addition, the polyester has a proportion of aliphatic and/or alicyclic copolymer units other than BD and HD of 3.
The content is preferably 0 mol% or less, and may be 0 mol%. If it exceeds 30 mol %, process efficiency tends to deteriorate, which is not preferable from the viewpoint of ensuring a high degree of process stability. B
Although the aliphatic and/or alicyclic copolymer components other than D and HD lower the melting point or hardness, it is preferable that the decrease in crystallinity is as small as possible, and therefore it is symmetrical and does not have bulky side chains. is desirable, but is not necessarily limited to this depending on the amount of copolymerization and the desired physical properties.

Specific examples include adipic acid, sebacic acid, hydroxyacetic acid, and ethylene glycol (EG).
, trimethylene glycol, pentamethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, cyclohexanedimethanol and propylene glycol, neopentyl glycol and the like.

[0036] The polyester used for the sheath component must satisfy the above-mentioned structural unit conditions, and also ensure stability in the fiber and nonwoven fabric manufacturing process at the commercial production level and quality as adhesive fibers and nonwoven fabrics. In order to do so, the following physical properties must also be satisfied. That is, the polyester constituting the sheath component has a melting point of 90 to 20
0°C, preferably 90-185°C, more preferably 1
00 to 175°C is used. Below 90℃,
The heat resistance of the fiber or nonwoven fabric is insufficient, resulting in poor practical performance. On the other hand, if the temperature exceeds 200°C, high temperatures are required for adhesion, making it impossible to use conventional equipment, or even if high-temperature processing equipment is used, the molded product may become deformed, its texture may deteriorate, and energy This is not preferable because there is a lot of loss.

The polyester constituting the sheath component has a heat of crystal fusion (ΔHu) of 2.0 cal/g or more, preferably 2.5 cal/g or more, and more preferably 3.0 cal/g.
1/g or more is used. If it is less than 2.0 cal/g, it is not preferable because it tends to cause sticking during fiber production. ΔH
To measure u, a sample is taken out from the molten polymer as fine fibrous or thin film pieces, cooled, and left at room temperature for three days or more, then subjected to a differential scanning calorimeter (DSC) at a rate of 10°C/min in nitrogen. It is determined by raising the temperature and determining the area of the endothermic peak during melting.

Furthermore, the polyester constituting the sheath component has a minimum crystallization time (CTmin.) of 80 seconds or less, preferably 70 seconds or less, and more preferably 50 seconds or less. If the time exceeds 80 seconds, sticking may occur during fiber production, which is undesirable.

CTmin. means that the crystallization start time is defined as the time at which substantially non-oriented film particles placed in a silicon bath or water bath at a predetermined temperature from a molten state are allowed to stand in the bath, and whitening starts. The crystallization start time at the shortest temperature in the temperature range of °C is the crystallization start time. CTmin. To obtain this, it is possible to leave it in the air without putting it in a bath, but it is preferable to do so in a bath because the heat exchange rate is higher and the influence of the cooling process can be reduced.In the present invention, Adopt the value in the bath. CTmin. To find CTmin., change the temperature. It is not necessarily necessary to measure it as such; it is a sufficient condition that the crystallization time at a certain temperature in the range of 0 to 120° C. is within 80 seconds. CTmin. In some cases, the temperature shown is close to 0℃,
It can also reach temperatures close to 120 degrees Celsius. The crystallization time in the actual fiber manufacturing process varies depending on temperature history, etc., but CTmin
．． It goes without saying that the crystallization rate in the process will be faster if the temperature is set to a temperature that indicates . Furthermore, when fibers are highly oriented as during spinning, the crystallization rate may increase, but the CTmin. can be used as a measure related to process efficiency.

[0040] When the secondary transition point of the polyester serving as the sheath polymer is lower than room temperature, it is preferable that the crystallization rate be as fast as possible. If oriented crystallization has not progressed by the time the fiber is wound up during spinning, problems such as sticking between single fibers may occur, which is not preferable.

[0041] The present invention provides durable hydrophilic properties, low elution properties, and low elution properties by incorporating an appropriate hydrophilic agent into a crystalline polyester that is composed of appropriate polymer units and has appropriate polymer physical properties. Heat-fusible fibers with excellent safety have become possible. The polyester constituting the sheath component may contain small amounts of additives such as antioxidants, optical brighteners, stabilizers, or ultraviolet absorbers. Further, the polyester may contain other copolymerized units within a range that satisfies the constitutional unit conditions defined in the present invention.

The fiber of the present invention is a composite fiber having the above polyester containing an N-POA compound as a sheath component and another melt-spun polymer as a core component. In order to maintain the purpose of the nonwoven fabric as a heat-adhesive and durable hydrophilic fabric and to maintain good fiber processability, it was found that a composite fiber structure is best.

As the core component, a thermoplastic polymer having a melting point of 150° C. or higher and higher than that of the polyester constituting the sheath component is used, examples of which include polyethylene terephthalate, polybutylene terephthalate, nylon-6, and nylon 6.6. , polypropylene, etc. In order to achieve the desired purpose as an adhesive fiber, the ratio of the N-POA compound-containing copolyester component to the total circumference of the cross-section of the composite fiber, that is, the cross-sectional circumference of the fiber, must be 5.
0% or more is preferable. In this case, it goes without saying that when emphasis is placed on the morphological stability of the adhesive fibers, it is necessary to use a thermoplastic polymer having a melting point higher than the adhesive processing temperature as the core component polymer. In order to maintain the fiber morphology after the adhesive treatment, the core component polymer must have a higher melting point than the sheath component polymer, preferably 40° C. or higher.

Specific examples of the cross-sectional shapes of the core-sheath type composite fibers of the present invention in composite form are explained with drawings.The complete single core-sheath type composite fibers as shown in FIG. 1, FIGS. 2, 3, and 5 A core-sheath type composite fiber with a core component having an irregular shape as shown in FIG. 4, a multicore core-sheath type composite fiber as shown in FIG. 4, an eccentric core-sheath type composite fiber as shown in FIG. Fibers, laminated composite fibers as shown in Figure 8, multi-layered composite fibers as shown in Figure 9, Figure 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 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. In addition, when it exceeds 80% by weight, fiber physical properties
In particular, this is not preferable because the yarn strength decreases.

The fibers of the present invention may be used as a fusion-treated fiber aggregate consisting only of composite fibers of N-POA compound-containing polyester and other polymers; It may also be used as a fused fiber aggregate.

[0046] Fiber aggregates cut into 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 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.

[0048] Furthermore, the N-POA 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 50.
ppm or less, whereas the N-POA compound of the present invention has a content of 50,000 ppm or more, which is much safer. Furthermore, as mentioned above, when the N-POA compound is kneaded into polyester, when the fibers are immersed in water and the dissolution of the kneading agent is examined, the ABS compound is 30% dissolved in the fiber in one month. N-PO
It was confirmed that the A-type compound content was 10% or less, and the elution property was 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 the water permeability, as shown in FIG. 13, an evaluation sheet for measurement was placed on cotton linter pulp, one drop of water was dropped from the buret 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.

[0051] Regarding durability, the test paper was
Washing was repeated 10 times according to method 0217-103, and after the 10 times, water permeability and water permeability measurements were performed to evaluate performance. Further, the intrinsic viscosity [η] in the examples is the intrinsic viscosity (dl/g) of polyester measured at 30° C. in a mixed solvent of equal weights of phenol and tetrachloroethane. The melting point (m.p) of polyester is determined by measuring the point at which the polarized light of the sample on the hot plate disappears, or the pouring point, using a micro-melting point measuring device.

[0052]

EXAMPLES Next, the present invention will be explained by examples, but the present invention is not limited by these examples. (Example 1) 260℃ using a polycondensation reactor in a conventional manner
A polycondensation reaction was carried out with 90 mol of TA, 10 mol of IPA,
A copolyester consisting of 100 moles of 1,6 hexanediol was produced, 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 the copolyester containing no additives are [η] 0.90, m・p 133~1
The crystallization time at 35°C, ΔH was about 8.0 cal/g, and 90°C was about 10 seconds. The resulting pellets were dried at 100°C in a vacuum dryer.

[0053] Then, the copolymerized polyester is melted,
Into the molten polymer, an N-polyoxyalkylene polyalkylene polyamine compound represented by the following formula (2),
HLB is 12.0, amine value 4.5, average molecular weight is approximately 5
0,000 with a small amount of hindered phenol antioxidant added, and then mixed uniformly with a static mixer, and then used as a sheath component.
On the other hand, using polyethylene terephthalate with [η] 0.67 as a core component, core-sheath composite spinning with a cross section shown in FIG. 1 was carried out at a core/sheath weight ratio of 50/50. The spinning head was extruded at a temperature of 290° C. and wound at a speed of 600 m/min. The wound fibers had almost no sticking 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 shrunk by 8% at 95°C in a water bath to obtain fibers with a fineness of 2.0 dr, a strength of 3.5 g/d, and an elongation of 43%. Ta. There were no problems such as sticking between single yarns during the drawing process.

[0054] 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 tapine paper machine to produce fiber paper. . After that, it was dried for 1 minute at 140℃ on a Yankee dryer-type floe board heated cylinder, and then glued to give a basis weight of 20g/m↑2, 40g/m↑2,
Handmade paper of 80g/m↑2 was produced. In either case, paper could be easily made without any problems with adhesion, and it maintained sufficient strength to withstand practical use.

[0055] 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,
The elution amount of the N-POA compound kneaded into the fiber into water was calculated using Talal Organic Carbon A.
When measured using a nalyser (TOC-500 manufactured by Shimadzu Corporation), approximately 5% of the N-POA compound kneaded into the fiber.
It was confirmed that only the front and rear elution occurred, and it was found that the level was not problematic.

[0056]

[Chemical formula 3]

(Comparative Example 1) The only difference from Example 1 is that it does not contain a hydrophilic agent. The sheath component is a copolymerized polyester, and the core component is polyethylene terephthalate with [η] 0.67, so that the core/sheath ratio is A core-sheath composite fiber having the cross section shown in FIG. 1 was spun at a weight ratio of 50/50. Spinning head temperature 29
It was extruded at 0°C 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.

[0058]

[Table 1]

Note) Wash according to JIS L0217
- Implemented in accordance with Law 103. Add and dissolve 2 g of synthetic laundry detergent in 1 liter of water at a liquid temperature of 40°C to obtain a washing liquid. A sample and, if necessary, a load cloth are added to the washing solution 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 at the same bath ratio, dehydrate again, Rinse for a minute and air dry. 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, a hydrophilic agent having the same molecular structure as the formula (2) but different in HLB value was used. In Example 4, one with HLB=8.0 was used, and 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 about 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.

It was found that all of the fiberizing process properties were good, the tearing length, which is a measure of the strength of the test paper, was large, and the hydrophilic properties were maintained at a good level even after 10 washes. 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.

[0063]

[C4]

In formula (3), R↓2 to R↓7 are PO and ED.
It is a random copolymer with an HLB of 12.0 and an average molecular weight of about 50,000. As a result, fibers with good fiberization process properties, durability, and good water absorption were obtained.

(Examples 19 to 23) 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, and 100 moles of 1,4-butanediol was obtained. manufacture,
In Example 20, a copolymerized polyester consisting of 83 moles of TA, 17 moles of IPA, 25 moles of EG, and 75 moles of 1,4-butanediol was produced by the same method as in Example 1.
Example 21 produced a polymer containing 100 moles of TA, 90 moles of 1,6-hexanediol, and 10 moles of diethylene glycol, and Example 22 produced a polymer containing 90 moles of TA, 10 moles of sebacic acid, and 100 moles of 1,6-hexanediol. In Example 23, 100 mol of TA, 1,4
A polymer containing 20 moles of -butanediol and 80 moles of 1,6-hexanediol was produced, and then a conjugate fiber to which a hydrophilic agent was added was produced 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-POA compound as in formula (2) was used, and a small amount of hindered phenol antioxidant was added to the copolymerized polyester of the sheath component. This case was carried out under the same conditions as in Example 1 except that N-POA was kneaded 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 it was added to the 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 same method as in Example 1 was carried out except for using the same additive. 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) As an additive, one having the same structure as the formula (2) but with HLB=5.0, that is, one rich in PO segment of hydrophobic group, was used, and the other conditions were as in Example 1. Performed in the same manner. Although the fiberization processability was good, the water absorption performance level was insufficient.

(Comparative Examples 6-7) Composite ratio: core/sheath = 10
The same method as in Example 1 was carried out except that core-sheath composite spinning having the cross section shown in FIG. 1 was carried out at a /90 weight ratio. 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 by the same method as in Example 1, and then the composite ratio was changed to core/sheath = 90.
Fibers were produced in the same manner as in Example 1, except that the weight ratio was changed to /10, and test paper was produced. The paper strength and hydrophilicity were insufficient.

(Comparative Examples 8 to 9) Each of the copolymerized polyesters listed in Table 2 was used as a sheath, and the core and
Although sheath composite spinning was performed, agglutination was observed between single fibers and agglutination also occurred between fiber bundles. Therefore, it was not possible to obtain a good paper that could be evaluated.

(Comparative Example 10) A polycondensation reaction was carried out by a conventional method to produce a copolymerized polyester consisting of 82 moles of TA, 18 moles of IPA, and 100 moles of EG, and having [η] 0.76 and ΔH 1.0 cal/g. The same amount of the hydrophilizing agent as in Example 1 was added, and spinning was performed in the same manner as in Example 1 to obtain spinning atoms. Then, it is stretched and shrunk to a fineness of 2.0d.
A fiber with a strength of 4.5 g/dr and an elongation of 30% was 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 hydrophilicity was good to some extent, but the tearing length was 0.1 km, which was very low strength.

[0072]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

(Example 24, Comparative Example 11) By the same method as in Example 1, a copolyester containing an N-POA compound was used as a sheath, polyethylene terephthalate with [η] 0.67 was used as a core, and A polyester binder fiber with a /sheath weight ratio of 50/50 was made, and the fineness was 2.0.
dr, and cut fibers with a fiber length of 5 mm were obtained. 70 parts by weight of the cut fiber and hydrophilic rayon (PB 1
505) 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 and made using a square tapie paper machine to produce fiber paper. After that, it was dried on a Yankee dryer type Ploe board heating cylinder at 120℃ for 1 minute and glued.
↑2 handmade paper was made. In either case, there were no problems with adhesion, the paper could be easily made, and it maintained sufficient strength to withstand practical use. In addition, as a comparative example, a binder fiber was produced that differed only in that it did not contain the 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 both papers was evaluated, the water permeability and water permeability results were shown in Table 6. In the case of this example, not only the initial performance but also excellent durable hydrophilicity was obtained. You can see that Furthermore, Comparative Example 11 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.

[0075]

[Table 6]

[0076]

Effects of the Invention As described above, the present invention uses a crystalline copolymerized polyester having a specific polymer composition and polymer physical properties, and furthermore, by incorporating a specific hydrophilic agent into the crystalline copolymerized polyester, the dissolution property can be improved. A durable hydrophilic heat-fusible conjugate fiber that has good durability, good hydrophilicity, and particularly good heat-fusion bonding to polyester fibers, and a part or all of the conjugate fiber. The objective is to provide the used nonwoven fabric without any trouble in the process.

[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: 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, as a sheath component, and having a melting point of 150
A core-sheath type conjugate fiber, the core component of which is a thermoplastic polymer having a higher melting point than the polyester constituting the sheath component at temperatures above .degree. C., and the weight ratio of the sheath component and the core component being 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 total amount of terephthalic acid units and isophthalic acid units occupying in the acid units is 60 mol% or more, and 1,6-hexanediol units and 1,6-hexanediol units occupying in the glycol units , 4-butanediol units in a total amount of 60 mol% or more. [C] Melting point is 90-200℃, heat of crystal fusion is 2.0
Cal/g or more, minimum crystallization time within 80 seconds.