JP2944558B2 - Elastic monofilament - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic monofilament having stretch elasticity. More specifically, the present invention relates to an elastic monofilament containing an elastic hydrogenated block copolymer as a main component and having little distortion and adhesion after expansion and contraction.

[0002]

2. Description of the Related Art As a material having elasticity, natural rubber,
Polyurethanes and block copolymers are known. Due to the weather, natural rubber fluctuates greatly in production, causing not only problems in stable production, but also allergies due to natural rubber, and conversion to synthetic products is desired. ing. In addition, polyurethane has poor heat stability and poor weather resistance of the product, and polyurethane itself has high cost disadvantages. Therefore, a material that replaces polyurethane is required.

[0003] Various proposals have already been made on elastic fibers comprising a hydrogenated block copolymer, which is the object of the present invention. For example, JP-B-8-19564 describes a composition that can be melt-extruded by mixing a specific three-block copolymer and a specific two-block copolymer. However, it is difficult to uniformly mix the two block copolymers, and it is very difficult to prepare the two block copolymers into a composition having desired properties in the polymerization step. This is because in the examples (Examples 1, 3 and Comparative Example A) of the same publication, the tensile strength was greatly reduced as the amount of the diblock copolymer was increased (Table 1 of the same publication). This is also clear from the fact that it indicates that it is difficult to uniformly mix the two-type block copolymer. Japanese Patent Application Laid-Open No. 64-70550 discloses a block copolymer blend, but this proposal also has the same problem as the above-mentioned Japanese Patent Publication No. Hei 8-19564.

Further, JP-A-6-57525 discloses specific three types of polymer blocks composed of butadiene, a polymer block composed of a vinyl aromatic compound, and a random copolymer block composed of a monomer mixture of isoprene and butadiene. A fiber comprising a hydrogenated block copolymer obtained by hydrogenating a block copolymer in which two polymer blocks have a specific arrangement is described.

However, the above publication only discloses fibers using a normal spinning machine with a fineness of several deniers or more that can be used as a multifilament, and the publication discloses this specific block copolymer. There is no description that can judge the suitability of the present invention for an elastic monofilament, particularly a monofilament monofilament having a large fineness. As is evident from the above, elastic monofilaments that are conventionally satisfactory enough.
In particular, a large fineness elastic monofilament was not known.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an elastic monofilament which can solve the above-mentioned problems which have been difficult to solve so far, that is, an elastic monofilament which has high breaking strength and low distortion and adhesion after expansion and contraction. It is to provide.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, an elastic monofilament capable of achieving the above object of the present invention was obtained by using a specific hydrogenated block copolymer. And found that the present invention was completed. That is, the present invention provides: A single filament fineness formed of a thermoplastic polymer that is mostly a hydrogenated block copolymer is a monofilament having a denier of 200 denier or more, and the hydrogenated block copolymer is mainly composed of a vinyl aromatic compound. Having at least two polymer blocks A, at least two polymer blocks B mainly composed of a conjugated diene compound, and at least one polymer block B at the end of the polymer chain; The content of the combined block A is 5 to 5.
1. An elastic monofilament characterized in that it is a hydrogenated block copolymer having a number average molecular weight of 70,000 to 110,000 obtained by hydrogenating a block copolymer of 30% by weight, Thermoplastic polymer 10 comprising 50 to 95 parts by weight of a hydrogenated block copolymer and 5 to 50 parts by weight of polyethylene
A monofilament having a single-fiber fineness of 200 denier or more formed at 0 parts by weight, wherein the hydrogenated block copolymer has at least two copolymer blocks A mainly composed of a vinyl aromatic compound. At least two polymer blocks B mainly composed of a conjugated diene compound.
And at least one polymer block B is at the end of the polymer chain, and the content of the polymer block A is 5
2. An elastic monofilament characterized in that it is a hydrogenated block copolymer having a number average molecular weight of 70,000 to 110,000 obtained by hydrogenating a block copolymer having a molecular weight of ３０30% by weight. Polymer block A of block copolymer before hydrogenation
Has a number average polymerization degree of 30 to 300, and the content of the polymer block B at the polymer chain end in the block copolymer is 3
-25% by weight, and the hydrogenated block copolymer M
3. The elastic monofilament according to claim 1 or 2, wherein FR has a value of 1 to 100. 4. The elastic monofilament according to claim 1, 2, or 3, wherein the monofilament has an 80% stretching strain of 20% or less. The polymer according to claim 1, wherein the thermoplastic polymer is a polymer containing 0.1 to 2 parts by weight of a fatty acid amide and 0.5 to 5 parts by weight of a powder compound based on 100 parts by weight of the polymer. 5. The elastic monofilament according to 3, 3 or 4, The vinyl aromatic compound is styrene, and the conjugated diene compound is butadiene.
An elastic monofilament according to 2, 3, 4 or 5.

Hereinafter, the present invention will be described in more detail. The elastic monofilament according to the invention consists for the most part of a thermoplastic polymer which is a specific hydrogenated block copolymer. This means that the particular hydrogenated block copolymer is present to bear most of the elastic function of the monofilament. The block copolymer before hydrogenation in the present invention comprises a block A mainly composed of a vinyl aromatic compound and a block B mainly composed of a conjugated diene compound. Examples of the vinyl aromatic compound constituting the block A used in the block copolymer before hydrogenation include styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, and the like. To achieve
Particularly, styrene is preferred. In the present invention, these compounds may be used alone or in combination of two or more.

The conjugated diene compound constituting the block B used in the block copolymer before hydrogenation in the present invention includes, for example, 1,3-butadiene, isoprene, 1,3
-Pentadiene, 2,3-dimethyl-1,3-butadiene and the like.
3-Butadiene and isoprene are particularly preferred. These compounds may be used alone or in combination of two or more. The block copolymer before hydrogenation in the present invention may be obtained by a conventionally known polymerization method, for example, by sequentially performing block copolymerization using a lithium alkyl catalyst such as n-butyllithium, or A block copolymer may be formed by performing a coupling reaction after sequentially performing block polymerization.

The thus obtained block copolymer before hydrogenation is then selectively hydrogenated. The hydrogenation reaction in the present invention is a known hydrogenation catalyst, for example, a supported catalyst of a noble metal system such as platinum or palladium, Raney nickel, an organic nickel compound, an organic cobalt compound or a compound in which these compounds are combined with another organic metal compound. The reaction can be performed using a catalyst or the like. In the present invention, it is preferable that this hydrogenation reaction is selectively performed on the double bond of the conjugated diene compound. If most of the double bonds of the conjugated diene compound are not hydrogenated, and if the double bonds are mostly present, the resulting monofilament is liable to decrease in the weather resistance, it is not preferable, and at least 80% by weight or more of the conjugated diene bond is hydrogenated. Is preferred. More preferably, 90% by weight or more of hydrogen is added.

The number average molecular weight of the hydrogenated block copolymer according to the present invention must be 70,000 to 110,000. Particularly preferably, 80,000 to 90,0.
00. If the number average molecular weight is less than 70,000 , the possibility that the monofilaments adhere to each other in the monofilament production process increases, and the possibility that the tensile strength of the obtained monofilament decreases may increase. Number average molecular weight of the block copolymer after hydrogenation is 1
If it exceeds 10,000, the hydrogenated block copolymer of the present invention has a high melt viscosity, the die pressure at the time of spinning increases, and the spinnability may be poor.
Further, if the melt viscosity is too high, irregularities will be formed on the surface of the obtained monofilament, and it will be difficult not only to expect uniform characteristics in the obtained monofilament, but also to cut the monofilament in the manufacturing process. This is not preferable because the problem described above tends to occur.

In the present invention, the polymer block A composed of a vinyl aromatic compound in the hydrogenated block copolymer can be provided with a high tensile strength to a monofilament from which a polymer block A composed of a conjugated diene compound is obtained. The hydrogenated block copolymer is constituted so as to impart stretch elasticity to the monofilament from which the block B is obtained.

In the present invention, it is preferred that the block A composed of a vinyl aromatic compound is polymerized so that the number average degree of polymerization is 30 to 300. 30 to 100 are particularly preferred. If the average degree of polymerization is less than 30, there is a possibility that sufficient properties as a monofilament elastic body cannot be provided. When the average degree of polymerization of block A exceeds 300,
The strain after expansion and contraction of the monofilament becomes large, and it becomes difficult to obtain the elastic monofilament aimed at by the present invention. In the present invention, the content of the block A in the block copolymer before hydrogenation needs to be 5 to 30% by weight, more preferably 5 to 20% by weight, and particularly preferably 10 to 20% by weight. %. If the content is less than 5% by weight, it may be difficult to impart sufficient elasticity to the monofilament. On the other hand, if it exceeds 30% by weight, the strain after expansion and contraction of the monofilament may increase.

The MFR (melt flow amount) of the block copolymer after hydrogenation in the present invention is preferably from 1 to 100, and more preferably from 5 to 20. MFR
Is less than 1, the spinning fluidity of the hydrogenated block copolymer in the spinning step becomes less stable, and as a result, the surface morphology of the spun yarn becomes uniform. Therefore, there is a possibility that a uniform shaped filament cannot be obtained and thus the obtained monofilament cannot have uniform characteristics. In addition, MFR is 10
If the block copolymer exceeds 0, the tensile strength of the monofilament may be reduced.

In the block copolymer before hydrogenation in the present invention, the polymer block B composed of at least one conjugated diene compound needs to be at the terminal of the polymer chain. By having the copolymer block B at the end of the polymer chain, the monofilament according to the present invention can be made into an excellent elastic monofilament having high breaking strength and small distortion after expansion and contraction. In the present invention, terminal block B occupying in the block copolymer before hydrogenation
Is preferably 3 to 25% by weight.
20% by weight is particularly preferred. When the amount of the terminal block B is less than 3% by weight, the melt viscosity is increased, and the spinnability may be poor. If it exceeds 25% by weight, the tensile strength of the monofilament may decrease.

In the polymer constituting the monofilament of the present invention, other polymers than the hydrogenated block copolymer can be added without departing from the object of the present invention. In the present invention, the properties of the monofilament comprising the hydrogenated block copolymer can be further improved by adding a specific amount of polyethylene to the hydrogenated block copolymer. That is, by using a block copolymer to which a specific amount of polyethylene is added, it is possible to suppress an increase in stretching strain of the obtained monofilament, and, as is clear when comparing the results of Examples 7 to 9 described below, A monofilament capable of exhibiting a desired stress-strain curve can be obtained. In addition, the addition of a specific amount of polyethylene during monofilament spinning
It is useful not only for improving the flow properties of the molten polymer, but also for reducing the tackiness of the resulting monofilament and significantly improving the handling operability of the monofilament.

As an example of the polyethylene used in the present invention,
Low density polyethylene (LDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDP)
E), very low-density polyethylene (VLDPE), very-low-density polyethylene (SSCPE), polyethylene copolymer and the like. Of these, low-density polyethylene (LDPE) is particularly preferred. In the present invention, it is preferable to add polyethylene so that the hydrogenated block copolymer is 50 to 95 parts by weight, the polyethylene is 5 to 50 parts by weight, and the total amount of the polymer is 100 parts by weight. Particularly preferred is a polymer adjusted to be 70 to 90 parts by weight of a hydrogenated block copolymer and 10 to 30 parts by weight of polyethylene. When the amount of polyethylene is less than 5 parts by weight, it is difficult to sufficiently obtain the effects expected when polyethylene is added. On the other hand, if the polymer has a composition of polyethylene exceeding 50 parts by weight, it is difficult to maintain the stretching strain of the monofilament intended in the present invention within an appropriate range.

The melt viscosity of the polyethylene used in the present invention is preferably from 0.5 to 250, particularly preferably from 1 to 10.
0 is preferred. It is preferable to use polyethylene having a melt viscosity close to the melt viscosity of the hydrogenated block copolymer. As a method of mixing the hydrogenated block copolymer and polyethylene, either a method of chip blending at the time of spinning or a method of using chips in which two kinds of polymers are melt-mixed in advance may be used. In the present invention, there is no particular reason to limit the use of these two mixing methods, but the latter is preferred because uniform blending is relatively easy. The hydrogenated copolymer used in the present invention, or the thermoplastic polymer composed of the copolymer and polyethylene, includes a fatty acid for improving the properties of the monofilament, and further, the process properties and the like in the production process of the monofilament filament. It is preferred to add an amide.

Examples of the fatty acid amide to be added include, for example, stearic acid amide, erucic acid amide, palmitic acid amide and the like, and in particular, stearic acid amide is preferable. The amount of the fatty acid amide to be added is preferably 0.1 to 2 parts by weight, particularly preferably 0.5 to 1 part by weight, per 100 parts by weight of the thermoplastic polymer.
When the amount of the fatty acid amide is less than 0.1 part by weight, the amount of the fatty acid amide deposited on the surface of the monofilament is small, and the monofilament may be adhered. When the amount of the fatty acid amide exceeds 2 parts by weight, the amount of the precipitated fatty acid amide exceeds an appropriate amount, and conversely, it functions as an adhesive, and the adhesion between the monofilament and the fatty acid amide is likely to occur. Not preferred.

In the present invention, a powder compound can be added to the thermoplastic polymer in order to improve the surface properties and mechanical properties of the monofilament. Examples of the powder compound in the present invention include, for example, calcium carbonate, diatomaceous earth, titanium oxide, talc, synthetic silica, glass balloon, and the like, or polymer powder that does not deform at the processing temperature, and calcium carbonate is particularly preferable. . The addition amount of the powder compound is the same as that of the thermoplastic polymer 1
0.5 to 5 parts by weight, preferably 1 to 100 parts by weight,
-4 parts by weight is particularly preferred. The powder compound forms minute irregularities on the surface of the monofilament.

If the amount of the powdered compound is less than 0.5 part by weight, the possibility of monofilament adhesion increases, which is not preferable. The powder compound itself tends to clog the spinneret filter, which is not preferable from the viewpoint of stable production. The particle size of the powder compound used in the present invention needs to be smaller than the pore size of the nozzle used for melt spinning, but the average particle size is preferably 0.1 to 30 μm, and the average particle size is 0.5 to 2 μm The particle size is particularly preferable. The monofilament of the present invention preferably has an 80% stretching strain of 20% or less, particularly preferably 15% or less. A monofilament having an 80% stretching strain of more than 20% may lack practically usable form retention as a stretching material.

The 80% stretching strain in the present invention is:
Set to 10cm between chucks with an autograph, 80%
This is measured by repeating the expansion and contraction two times continuously to obtain the elongation of the monofilament when the strength becomes 0 at the second return. The monofilament according to the present invention is preferably a filament having a single yarn fineness of 200 denier or more, and particularly preferably a filament having a large fineness of 1000 denier or more. If the denier is less than 200 denier, the resistance of water in the water at the time of cooling the spun filament increases the possibility that the monofilament is cut,
In addition, the resistance may cause the monofilament to be in a stretched state, and a uniform product may not be obtained. The cross-sectional shape of the monofilament according to the present invention may be any of a flat cross-section, a polygonal cross-section and the like in addition to a general round cross-section. The thus obtained elastic monofilament according to the present invention has particularly excellent strain characteristics, blocking properties and weather resistance, and is most suitable as an elastic material.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The stretchable monofilament of the present invention will be described below based on examples. The number average molecular weight in the present invention is GPC (GEL PERMENTION CHROMATOGRAPH).
It was determined from the molecular weight in terms of styrene according to Y). In the present invention, 10 mg of a sample was dissolved in 20 ml of THF using LC-9A manufactured by Shimadzu Corporation and measured at a flow rate of 1.8 ml / min. The MFR of the present invention is JIS K7210-1.
It was measured at 230 ° C. under a load of 2.16 kg by the method specified in 995 (Method A). However, polyethylene was measured at 190 ° C. which is generally used.

The 80% stretching strain was measured by an autograph (AGS100G) manufactured by Shimadzu Corporation, and the distance between chucks was 10 c.
m, expand and contract up to 80% (head moving speed 1
(0 cm / min) was continuously repeated twice, and the elongation was measured by reading the elongation when the strength reached 0 g in the second return.
In general, the elongation recovery rate or the residual strain rate described in JISL1096 may be used, but in the case of an elastic monofilament, it is important to return to the original length immediately after stretching, In the present invention, stretching strain is defined by elongation after continuous stretching.

[0025]

Examples 1 to 3 and Comparative Examples 1 to 7 A butadiene-styrene-butadiene-styrene type block copolymer was synthesized by performing block copolymerization using an n-butyllithium catalyst. The polystyrene content of this copolymer is 2
It was 0% by weight. This polymer was hydrogenated to form a pellet, and a hydrogenated block copolymer having a number average molecular weight of 85,000 was obtained.

The obtained hydrogenated block copolymer is charged into a single screw extruder and melted by heating (extruder temperature: 220 ° C.,
(220 ° C., 230 ° C., 270 ° C.), discharged from a nozzle having a hole diameter of 1.2 mm, and immediately taken out at 27 m / min while cooling in water at 20 ° C. to obtain a 6000 denier monofilament (Example 1). Similarly, monofilaments of Examples 2, 3 and Comparative Examples 1 to 4 were obtained by changing the number average molecular weight and the styrene ratio. Styrene-isoprene-styrene type hydrogenated block copolymer (Kuraray
A monofilament was obtained by spinning in the same manner as in Example 1 except that Septon 2002) (Comparative Example 5) was used.

Styrene-butadiene-styrene type hydrogenated block copolymer (Kraton G-Shell Chemical Co., Ltd.)
1652, the content of a vinyl aromatic compound was 29%), and spinning was carried out in the same manner as in Example 1 (Comparative Example 6). However, in this case, it was recognized that the melt viscosity was high and large irregularities were generated on the monofilament surface. When the extrusion temperature was increased to 310 ° C., the surface of the monofilament was no longer uneven, but it was confirmed that a large amount of smoke considered to be a decomposition gas was generated, and it was not possible to stably produce an elastic monofilament.

The evaluation results of the monofilaments obtained in the above Examples and Comparative Examples are summarized in Table 1. As is clear from Table 1, when the number average molecular weight of the hydrogenated block copolymer is 120,000 or more, it is observed that irregularities are generated on the surface of the monofilament, and therefore, it is found that a monofilament having uniform elasticity cannot be obtained. . In the case of a hydrogenated block copolymer having a number average molecular weight of less than 60,000, in the spinning and production steps, the adhesion of the yarn was so strong that it could not be released. Further, when the polystyrene content exceeds 30%, it is apparent that the 80% stretching strain exceeds 20%, which is an appropriate value for achieving the object of the present invention, and this case is not preferable as a stretching material.

[0029]

Examples 4 to 9, Comparative Examples 7 to 8 The hydrogenated block copolymer (number average molecular weight 85,000, polystyrene content 20% by weight) obtained in Example 1 and polyethylene as a polyolefin (Examples 5, 7, Example 1 except that 8, 9, Comparative Example 8), polypropylene (Comparative Example 7), and ethylene-ethyl acrylate copolymer (Example 6) were selected and blended in a pellet form using a tumbler-type blender.
6000 denier monofilament was obtained. As a blank, a monofilament of Example 4 was obtained in exactly the same manner as in Example 5, except that no polyolefin was added. Table 2 summarizes the evaluation results of the obtained monofilaments.

As is apparent from Table 2, when polyethylene is blended, the 80% stretching strain exceeds 20%, and the monofilament intended for the present invention cannot be obtained. Even when polyethylene is blended, if 80 parts by weight or more is blended, the 80% stretching strain becomes 20% or more, and it is apparent that the subject of the present invention cannot be achieved similarly.

[0031]

Examples 10 to 15 75 parts by weight of the hydrogenated block copolymer pellets obtained in Example 1, 25 parts by weight of polyethylene (Suntech LDPE F2225 manufactured by Asahi Kasei Corporation), and calcium carbonate were added in an amount of 4 parts by weight of the total weight of the polymer. % Of stearic acid amide and 1% of the total weight of the polymer were blended and melt-blended by a twin-screw extruder, and then re-pelletized. This melt-blended pellet was prepared in Example 1
Melted with the single screw extruder used in the above, slit width 0.2mm,
After discharging from a slit having a slit length of 25 mm and cooling in water, the monofilament was wound around a paper tube at a speed of 65 m / min. The adhesion of the obtained monofilament after winding the paper tube was evaluated, and the results are shown in Table 3. By winding around a paper tube, the winding force makes the yarns easily adhere to each other. However, as is apparent from Table 3, by blending the fatty acid amide and the powder compound, the adhesion of the monofilament is further improved. In the present invention, it is particularly desirable to use a fatty acid amide and a powder compound in combination, and the combined use significantly improves the adhesion.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

The elastic monofilament of the present invention has a small distortion after expansion and contraction, the adhesion as a monofilament is greatly improved, and the strength of expansion and contraction can be arbitrarily changed according to the application. . Due to these properties, it can be widely used for stretch tapes, bandages, diapers, and the like, and even clothing.

Continuation of the front page (56) References JP-A-2-259151 (JP, A) JP-A-3-130402 (JP, A) JP-A-8-13237 (JP, A) JP-A-4-257361 (JP) , A) JP-A-6-57525 (JP, A) JP-A-61-155446 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) D01F ⁶ /28-6/30 D01F 6/44-6/48

Claims (6)

(57) [Claims] 1. A single fiber fineness of 200 denier formed of a thermoplastic polymer which is mostly a hydrogenated block copolymer.
At least two polymer blocks A mainly composed of a vinyl aromatic compound, and at least two polymer blocks B mainly composed of a conjugated diene compound. It was obtained by hydrogenating a block copolymer having two and having at least one polymer block B at the end of the polymer chain and having a polymer block A content of 5 to 30% by weight. The number average molecular weight is 70,000 to 110,
000 hydrogenated block copolymers. 2. The fineness of a single yarn formed from 100 to 100 parts by weight of a thermoplastic polymer comprising 50 to 95 parts by weight of a hydrogenated block copolymer and 5 to 50 parts by weight of polyethylene is 200 denier.
Or more monofilaments, wherein the hydrogenated block copolymer comprises at least two polymer blocks A mainly composed of a vinyl aromatic compound and at least a polymer floc B mainly composed of a conjugated diene compound. It was obtained by hydrogenating a block copolymer having two and having at least one polymer block B at the end of the polymer chain and having a polymer block A content of 5 to 30% by weight. The number average molecular weight is 70,000 to 110,
000 hydrogenated block copolymers. 3. The number average polymerization degree of the polymer block A of the block copolymer before hydrogenation is 30 to 300, and the content of the polymer block B at the polymer chain end in the block copolymer is 3 to 300. The elastic monofilament according to claim 1 or 2, wherein the MFR is 25% by weight and the MFR of the hydrogenated block copolymer is 1 to 100. 4. The monofilament according to claim 1, wherein the 80% stretching strain is 20% or less.
An elastic monofilament as described. 5. The thermoplastic polymer according to claim 1, wherein the thermoplastic polymer is a polymer containing 0.1 to 2 parts by weight of a fatty acid amide and 0.5 to 5 parts by weight of a powdery compound based on 100 parts by weight of the polymer. Item 5. The elastic monofilament according to item 1, 2, 3, or 4. 6. The vinyl aromatic compound is styrene,
The elastic monofilament according to claim 1, 2, 3, 4, or 5, wherein the conjugated diene compound is butadiene.