JP2731597B2 - Method for producing polyurethane ultrafine fiber nonwoven fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

TECHNICAL FIELD The present invention relates to the production of a polyurethane ultrafine fiber nonwoven fabric by a melt-blown spinning method having good uniformity.

2. Description of the Related Art Conventionally, there have been several proposals for melt-spinning a thermoplastic polyurethane to obtain a polyurethane filament and for further converting a polyurethane fiber into a nonwoven fabric. Further, it has been proposed in Japanese Patent Application Laid-Open Nos. 61-22855, 61-55248 and 1-30945 to obtain a polyurethane elastic fiber nonwoven fabric by spinning thermoplastic polyurethane by a melt blown spinning method. ing. In addition, after kneading a polyisocyanate compound into a melted thermoplastic polyurethane elastic body, it is possible to manufacture a nonwoven fabric by depositing and collecting in a sheet shape by a melt blown method.
Japanese Patent Publication No. 64-8746, Japanese Patent Publication No. 64-8747 discloses a polyurethane nonwoven fabric obtained by melt-kneading an ether-based thermoplastic polyurethane alone or with a polyisocyanate compound and then spinning it by a melt blown spinning method to form a sheet. Japanese Patent Application Laid-Open (JP-A) No. 63-28 discloses the production of a reticulated sheet by heating and pressing.
No. 2362, fused polyurethane elastic fiber non-woven fabric obtained by melt blown method in the form of gloves with a high-frequency welder,
Japanese gazette of Japanese Patent Publication No. 64-8724 discloses that a nonwoven fabric of a thermoplastic polyurethane obtained by a melt-blown spinning method of a polyester-based thermoplastic polyurethane is bonded to a cloth-like material to form an attached cloth. JP-A-64-40655 further discloses, as a specific polyurethane, 3-methyl-
Japanese Patent Application Laid-Open No. 1-132858 proposes producing a nonwoven fabric by spinning a polyurethane having a polyester diol of 1,5-pentanediol and dicarboxylic acid as a soft segment by a melt blown spinning method.

[Problems to be solved by the invention]

In the conventional melt spinning of a thermoplastic polyurethane, the fiber is spun at a high temperature equal to or higher than the dissociation temperature of the urethane bond of the polyurethane, so that the polyurethane chains are cut off, so that fibers and nonwoven fabrics having sufficiently satisfactory performance cannot be produced.
As a countermeasure, for example, as proposed in Japanese Patent Publication No. 64-8746, a polyisocyanate compound is added and spun to form a chain recombination or cross-link to maintain fiber performance. ing. However, a compound having high activity such as polyisocyanate causes an irregular cross-linking reaction or a partial reaction, so that a good fiber cannot be obtained. Further, the polyurethane melt has a large viscosity, and it is difficult to produce fine fibers with good homogeneity. The present invention does not cause undesired irregular cross-linking reaction or partial reaction as in the case of using a polyisocyanate, has good thread quality, and has a finely divided material having good homogeneity.
It is an object of the present invention to provide a method for producing a polyurethane nonwoven fabric with less sticking by a melt blown spinning method. Furthermore, light stability,
An object of the present invention is to provide a polyurethane ultrafine fiber non-woven fabric having excellent hydrolyzability, small yellowing and little oxidative deterioration, and good elasticity.

[Means for Solving the Problems]

The present invention provides a polyester diol having an average molecular weight of 600 to 3,000 obtained by reacting an aliphatic or alicyclic diol having 8 to 12 carbon atoms with an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid ester, and an aromatic and / or aromatic diol. A thermoplastic polyurethane obtained by reacting an organic diisocyanate mainly composed of an alicyclic diisocyanate with a chain extender having at least two active hydrogen atoms contains at least one selected from hindered phenols and benzotriazoles. A process for producing a polyurethane ultrafine fiber nonwoven fabric, characterized by adding 0.5 to 3% by weight of various kinds of compounds and spinning by a melt blown spinning method. Further, the present invention provides an aliphatic or alicyclic diol having 8 to 12 carbon atoms and an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid ester obtained by a reaction with an average molecular weight of 600 to 3,000.
Hindered phenols to a thermoplastic polyurethane obtained by reacting a polyester diol of the formula (I) with an organic diisocyanate mainly composed of an aromatic and / or alicyclic diisocyanate and a chain extender having at least two active hydrogen atoms. And 0.5 to 3% by weight of at least one compound selected from benzotriazoles and 0.05 to 2% by weight of silicone oil having a viscosity of 2 to 150 poise at 30 ° C. and spinning by melt blown spinning. This is a method for producing a polyurethane ultrafine fiber nonwoven fabric. Thermoplastic polyurethane applied to the present invention, polyester diol by condensation polymerization of low molecular weight diol and dicarboxylic acid, polylactone diol obtained by ring-opening polymerization of lactam, polyoxyalkylene glycol, average molecular weight of 500 such as polyalkylene carbonate glucose. A thermoplastic polyurethane obtained by reacting a polymer glycolose, an organic diisocyanate, and a low molecular weight compound having two active hydrogen atoms of up to 3.000. Particularly preferred thermoplastic polyurethanes are aliphatic or alicyclic diols having 8 to 12 carbon atoms, such as 1,8-octanediol, 1,9-diol.
Nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2- or 3
Linear or side chain aliphatic such as -methyl-1,7-heptanediol, 2- or 3-methyl-1,8-octanediol, ω, ω'-dihydroxy-1,4-dimethylcyclohexane At least one diol selected from diols or alicyclic diols, and an aliphatic dicarboxylic acid, for example, succinic acid, glutaric acid, adipic acid,
Pimelic acid, suberic acid, azelaic acid, sebacic acid,
Average molecular weight obtained by reacting at least one type of dicarboxylic acid selected from dodecane dicarboxylic acid or esters of these dicarboxylic acids or esters thereof
600 to 3,000 polyester diols, and as organic diisocyanate, for example, phenylene diisocyanate,
Organic diisocyanates mainly composed of aromatic or alicyclic diisocyanates such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate and xylylene diisocyanate, and An organic diisocyanate selected from an aliphatic diisocyanate or a diisocyanate having a naphthalene ring if necessary,
It is a low molecular weight compound having two active hydrogen atoms, for example, a chain extender selected from diol, amino alcohol, hydrazine, diamine and the like. Then, a polymer diol, an organic diisocyanate, and a chain extender are selected at a desired composition ratio, and polymerized by a melt polymerization method, a bulk polymerization method, a solution polymerization method, or the like to obtain a thermoplastic polyurethane. In order to obtain a nonwoven fabric with good uniformity, the content of the polymer diol which is a soft segment in the thermoplastic polyurethane is 45 to 75% by weight in the composition at the time of polyurethane production. The chain extender is a polyurethane polymerized using a chain extender mainly composed of a compound selected from low-molecular-weight aliphatic diols and isophoronediamine, and has an intrinsic viscosity [η] of 0.06 to 0.12 / 0.12. Polyurethane whose degree of polymerization is adjusted to be in the range of g is preferred from the viewpoint of melt blown properties. However, when a polyurethane is produced by a melt polymerization method, and a non-woven fabric is directly formed by a melt blown spinning method without being taken out, the intrinsic viscosity at the time of spinning (η) is 0.
The degree of polymerization is adjusted so as to be in the range of 05 to 0.10 / g. When the content of the soft segment in the polyurethane is less than 45% by weight, it is good in terms of spinnability and ultrafine fibers, but in terms of softness, stretchability, shape stability, and surface smoothness of the nonwoven fabric. Not preferred. Also, the soft segment content
If the content exceeds 75% by weight, the flexibility of the nonwoven fabric is good, but the spinnability and the formation of ultrafine fibers deteriorate, and a nonwoven fabric with good formation cannot be obtained. On the other hand, if the intrinsic viscosity [η] of the polyurethane is small, a sufficiently fine fiber cannot be obtained and a non-woven fabric of fibers having an uneven thickness is obtained. On the other hand, when the intrinsic viscosity [η] of the polyurethane is large, the melt viscosity becomes high, and a good fiber flow cannot be formed. Next, as a hindered phenol compound to be added to the thermoplastic polyurethane, for example, 1,3,5-tris (4
-Tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, 1,3,5-tris (3,5-tert-butyl-4-hydroxybenzyl) isocyanuric acid, triethylene glycol-bis [3 -(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate]. On the other hand, as the benzotriazole compound, for example, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-
5'-t-butylphenyl) benzotriazole, 2-
(2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-
3 ', 5'-di-t-amylphenyl) benzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole, 2- {2'-hydroxy-
3 '-(3 ", 4", 5 ", 6"-tetrahydrophthalimidomethyl-5'-methylphenyl) benzotriazole and the like. These compounds are added to the polyurethane prior to melting the polyurethane or prior to spinning. The addition amount is 0.5 to 3 with respect to the thermoplastic polyurethane.
% By weight. The action of these additives is to stabilize the active groups possessed by the additives by positively reacting with the dissociated portions in order to prevent the heated and melted polyurethane from dissociating and causing undesirable side reactions. In addition, it is to provide the effect of suppressing the oxidation or light deterioration of the additive. Therefore, when the amount of the additive is small, the dissociated portion of the polyurethane is sufficiently blocked and cannot be stabilized. On the other hand, when the amount of the additive is large, the additive causes an undesirable side reaction to the polyurethane, which deteriorates the performance of the polyurethane. In addition, in the present invention, in order to improve the spinnability and spinnability of the polyurethane, and to form a sufficiently fine fiber stream,
Silicon oil is added to the polyurethane at any stage before spinning. The silicone oil used in the present invention is a compound which is inert to molten polyurethane and does not increase the vapor pressure of the molten polyurethane yarn.
An oil selected from silicone oil in the range of ~ 150 poise, for example, compounds such as dimethylpolysiloxane and methylphenylpolysiloxane, and other heat-resistant general silicone oils, is used in an amount of 0.05 to 2% by weight based on the polyurethane. Is added. Next, the melt blown spinning method of the polyurethane composition is performed under the conditions of a spinning temperature of 230 to 280 ° C., a melt viscosity at the spinneret of 440 poise or less, and a carrier gas pressure (gauge pressure) of 0.5 to 5 kg / cm ² . By spinning, ultrafine fibers having an average fiber diameter of 10 μm or less can be obtained, and a fiber stream having good uniformity can be formed. By collecting this fiber stream in a sheet shape on a conveyor net, it is possible to obtain a polyurethane ultra-fine fiber non-woven fabric having a wide width and good uniformity. When the spinning temperature is increased, the melt viscosity of the polyurethane composition decreases, and the spinnability is improved, but the dissociation of urethane bonds increases, and the resulting nonwoven fabric tends to have poor physical properties. And spinnability decreases. When the spinning temperature is lowered, the dissociation decreases, but the melt viscosity increases, and good ultrafine fibers cannot be obtained. Therefore, the preferable melt viscosity at the spinneret is 400 poise or less. The method for producing a polyurethane ultrafine fiber nonwoven fabric of the present invention comprises:
Since the melted polyurethane has good fluidity and the spun polyurethane fiber has good spinnability, it can be sufficiently finely divided, and the fiber stream has less sticking to form a fiber stream having good dispersibility. For this reason, the obtained polyurethane ultrafine fiber nonwoven fabric has good homogeneity. Further, a non-woven fabric product having high strength and elongation with little side reaction due to dissociation and thermal decomposition of polyurethane can be obtained. Furthermore, it is a nonwoven fabric having high oxidation resistance, light deterioration resistance and hydrolysis resistance with high durability. The polyurethane microfiber nonwoven fabric obtained by the present invention is useful for bandages, supporters, base cloths for adhesive materials, training wear, training pants, bands, base materials for leather-like sheets, and the like.

[Action]

When a thermoplastic polyurethane is melt-spun by a melt-blown method, it is exposed to air at a high temperature for a relatively longer time than a normal spinning method, so that activated portions such as dissociation formed during melting cause undesirable side reactions. . The hindered phenol and / or benzotriazole added to the polyurethane blocks the activated portion of the polyurethane, thereby inhibiting and stabilizing side reactions. Furthermore, by adding silicone oil, the flowability of the molten polyurethane is improved, and the spinning property of the spun polyurethane fiber is improved,
The fineness can be sufficiently reduced, and the dispersibility can be enhanced by reducing the sticking of the fiber stream.

【Example】

Next, embodiments of the present invention will be described with reference to specific examples, but the present invention is not limited to these examples.
The parts and percentages in the examples relate to weight unless otherwise specified. The intrinsic viscosity [η] of the polymer of the present invention was dissolved in N, N′-dimethylformamide and measured at a temperature of 30 ° C. using a capillary viscometer, and the intrinsic viscosity [η] was determined by the following equation. Here, t is the flow time of the solution (second) t ₀ is the flow time of the solvent (second) c is the concentration of the polymer (g /) Further, the melt viscosity at the spinneret of the present invention is the pressure at the spinneret, It was determined by measuring the discharge diameter and discharge amount. Example 1 Poly-2-methyl- having an average molecular weight of 2,000 and obtained by condensation polymerization of 2-methyl-1,8-octanediol and adipic acid.
1,8-octane adipate glycol as a polymer diol component, 1 mol% of polymer diol (61% of soft segment content), 4 mol% of 4,4'-diphenylmethane diisocyanate, 3 mol% of 1,4-butylene glycol
Is polymerized by a melt polymerization method to obtain an intrinsic viscosity [η] = 0.
107 / g of polyurethane [I] was obtained. After the polyurethane [I] was melt-polymerized, it was taken out as a strand, cut, and pelletized. This polyurethane pellet has 1,
3,5-tris (4-tert-butyl-3-hydroxy-2,6-
1.3% dimethylbenzyl) isocyanuric acid and 30 ° C
1% dimethylpolysiloxane with a viscosity of 3.8 poise
Melt-blown die with melted polyurethane composition added by extruder, nozzles with 0.3mm diameter discharge holes arranged in a row at 1mm intervals, and 0.25mm wide gas ejection slits on both sides The spinning temperature is 245 ° C (with a melt viscosity of 3 at the spinneret).
Spun under the conditions of 90 poise), air temperature of 290 ° C and air pressure of 2.5 kg / cm ² , and the spun ultrafine fiber stream is collected on a net of a collector installed about 25 cm from the die. , Average weight
100 g / m ² of meltblown ultrafine fiber nonwoven fabric (1) was obtained. The spinnability of this polyurethane was good, and a fine fiber stream with good uniformity could be formed. The average fiber diameter of the polyurethane was about 7.6 microns. The intrinsic viscosity of the polyurethane after spinning (η) is 0.089 /
g Comparative Example 1 Spinning was performed under the same conditions as in Example 1 except that the spinning temperature was 230 ° C. (melt viscosity at the spinneret portion was 550 poise). As a result, the spinnability was poor, and the polyurethane did not become ultrafine fibers but formed an uneven deposit. Comparative Example 2 The polyurethane [I] obtained in Example 1 was spun by a melt blown method under the conditions of Example 1 without adding both additives added in Example 1. As a result, the spinnability is poor,
The nonwoven fabric was irregular in fiber flow, causing unevenness in the deposited state and poor uniformity. The average fiber diameter was about 5.3 microns for thin fibers and about 18.2 microns for thick fibers. Furthermore, the intrinsic viscosity [η] of the polyurethane after spinning was 0.066 / g, and the decrease in viscosity was large. Comparative Example 3 A polyurethane composition obtained by adding 1% of dimethylpolysiloxane having a viscosity of 3.8 poise at 30 ° C. to the polyurethane [I] obtained in Example 1 was melted by an extruder, and spun by a melt blown method under the conditions of Example 1. did. As a result, the spinnability and the fiber stream forming property were relatively good, the deposition state of the ultrafine fiber stream was good, and the average fiber diameter was about 8.2 microns. However, the intrinsic viscosity [η] of the polyurethane after spinning was 0.071 / g, indicating a large decrease in viscosity. Example 2 Poly-2-methyl- having an average molecular weight of 2,000 obtained by condensation polymerization of a mixed diol of 2-methyl 1,8-octanediol (30 parts) and 1,9-nonanediol (70 parts) and adipic acid.
1,8-octane / 1,9-nonane adipate glycol as a polymer diol component, and 1 mol% of polymer diol
(Soft segment 55.4%), composition of 5 mol% of 4,4'-diphenylmethane diisocyanate and 4 mol% of 1,4-butylene glycol were polymerized by a melt polymerization method, and the intrinsic viscosity [η] = 0.097 /% Of polyurethane [II]. After melt polymerization, this polyurethane [II] was taken out as a strand, cut, and pelletized. 1,3,5-Tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid 1.0 was added to the polyurethane pellet.
%, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole and 1% of dimethylpolysiloxane having a viscosity of 3.8 poise at 30 DEG C. were melted by an extruder. And spun by a melt blown method under the same conditions as in Example 1,
The ultrafine fiber stream is collected on the net of the collector and the average weight is 150 g.
/ m ² of the melt blown ultrafine fiber nonwoven fabric (2). As a result, the spinnability and spinnability of the polyurethane were good, and an ultrafine fiber stream with good uniformity could be formed. The nonwoven fabric is made of ultrafine fibers having an average fiber diameter of about 7.4 microns, and the intrinsic viscosity [η] of the polyurethane after spinning is
It was 0.091 / g. The nonwoven fabric was subjected to a hydrolysis resistance test using a jungle tester at a temperature of 70 ° C and a humidity of 95%. As a result, after 15 days, the intrinsic viscosity [η] was 0.053 / g, and the heat resistance and light resistance The test was excellent. The nonwoven fabric was embossed at 135 ° C. with a belt embossing machine in which an uneven pattern was engraved on one side, and the fibers were partially adhered in a pattern. The obtained nonwoven fabric had good elasticity, was soft and had good skin contact properties, and was useful as a supporter for joints. Example 3 Polymerization was carried out by a melt polymerization method in a composition of 1 mol% of poly 1,10-decane adipate glycol having an average molecular weight of 2,000, 5 mol% of diphenylmethane diisocyanate, and 4 mol% of 2-methyl-1,5-pentane glycol. Intrinsic viscosity [η]
= 0.092 / g of polyurethane and triethylene glycol-bis [3- (3-t-butyl-5-methyl-4
-Hydroxyphenyl) propionate] 1.0%, 2-
A polyurethane composition obtained by adding 1.0% of (2'-hydroxy-5'-t-butylphenyl) benzotriazole was spun at a spinning temperature of 250 ° C., a conveying air temperature of 290 ° C. and air using the same melt blown apparatus as in Example 1. The fiber was spun under a pressure of 2.3 kg / cm ² , and the spun ultrafine fiber stream was collected on a net of a collector to obtain a melt-blown ultrafine fiber nonwoven fabric (3) having an average basis weight of 75 g / m ² . The intrinsic viscosity [η] of the polyurethane after spinning was 0.083 / g, and excellent results were obtained in the hydrolysis resistance and light resistance tests. One surface of this ultrafine fiber nonwoven fabric (3) was embossed at 135 ° C. with a smooth surface belt embossing machine, and the fibers were partially adhered. The obtained nonwoven fabric had elasticity, was soft, had good skin contact properties, had good spreadability of the drug, and was suitable as a base material for a patch.

【The invention's effect】

The method for producing a polyurethane ultrafine fiber nonwoven fabric of the present invention comprises:
The flowability of the molten polyurethane is good, and the spun polyurethane fiber has good spinnability, so that it can be sufficiently finely divided, and the fiber stream is less stuck and forms a fiber stream with good dispersibility. For this reason, the obtained polyurethane ultrafine fiber nonwoven fabric has good homogeneity. Further, a non-woven fabric product having high strength and elongation with little side reaction due to dissociation and thermal decomposition of polyurethane can be obtained. Furthermore, it is a nonwoven fabric having high oxidation resistance, light deterioration resistance and hydrolysis resistance with high durability.

Claims (2)

(57) [Claims] 1. A polyester diol having an average molecular weight of 600 to 3,000 obtained by reacting an aliphatic or alicyclic diol having 8 to 12 carbon atoms with an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid ester, and an aromatic and / or aromatic diol. Or a thermoplastic polyurethane obtained by reacting an organic diisocyanate mainly composed of an alicyclic diisocyanate with a chain extender having at least two active hydrogen atoms, at least one selected from hindered phenols and benzotriazoles A method for producing a polyurethane ultrafine fiber nonwoven fabric, comprising adding one type of compound in an amount of 0.5 to 3% by weight and spinning by a melt blown spinning method. 2. A polyester diol having an average molecular weight of 600 to 3,000 obtained by reacting an aliphatic or alicyclic diol having 8 to 12 carbon atoms with an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid ester, and an aromatic and / or aromatic diol. Or a thermoplastic polyurethane obtained by reacting an organic diisocyanate mainly composed of an alicyclic diisocyanate with a chain extender having at least two active hydrogen atoms, at least one selected from hindered phenols and benzotriazoles Production of a polyurethane ultrafine fiber nonwoven fabric characterized by adding 0.5 to 3% by weight of one compound and 0.05 to 2% by weight of silicone oil having a viscosity of 2 to 150 poise at 30 ° C. and spinning by melt blown spinning. Method.