JPH0376856A - Production of nonwoven fabric of extremely thin yarn of polyurethane - Google Patents

Abstract

PURPOSE:To obtain the title nonwoven fabric useful as a bandage, etc., having excellent uniformity by spinning a thermoplastic urethane comprising a specific polyester diol, an organic diisocyanate and chain extender. CONSTITUTION:A thermoplastic urethane obtained by reacting (A) a polyester diol having 600-3,000 average molecular weight prepared by reacting (i) 8-12C aliphatic or alicyclic diol with (ii) an aliphatic dicarboxylic acid or aliphatic dicarboxylic ester with (B) an organic diisocyanate consisting essentially of an aromatic and/or alicyclic diisocyanate and (C) a chain extender excellent at least two active hydrogen atoms is spun by melt blown spinning at <=400 poise melt viscosity at spinneret to give the objective nonwoven fabric. Preferably (D) a compound selected from hindered phenols and benzotriazoles is added to the thermoplastic polyurethane.

Description

[Detailed description of the invention] [Industrial application field]

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

[Conventional technology]

Conventionally, a number of proposals have already been made to obtain polyurethane filaments by melt-spinning thermoplastic polyurethane, and to make polyurethane fibers into nonwoven fabrics. Furthermore, it is also possible to obtain a polyurethane elastic fiber nonwoven fabric by spinning thermoplastic polyurethane using a melt-blown spinning method, as disclosed in JP-A-61-22855 and JP-A-61-5.
This method has been proposed in Japanese Patent Publication No. 5248, Japanese Patent Publication No. 1-30945, etc. In addition, it has been disclosed in Japanese Patent Publication No. 8746/1987 that a polyisocyanate compound is kneaded into a molten thermoplastic polyurethane elastomer, and then deposited and collected in a sheet form using a melt blowing method to produce a nonwoven fabric.
No. 8747 discloses that a polyurethane nonwoven fabric obtained by melt-kneading an ether-based thermoplastic polyurethane alone or with a polyisocyanate compound, then spinning it using a melt-blown spinning method and laminating it into a sheet shape is heated and pressurized to produce a reticulated sheet. According to Japanese Patent Application Laid-open No. 63-282362,
Patent Publication No. 1987-8724 discloses a glove obtained by melt-blown polyurethane elastic fiber non-woven fabric obtained by a high-frequency welder and melt-cut into the shape of a glove. JP-A-64-40655 discloses that a nonwoven fabric of plastic polyurethane and a cloth-like material are laminated together to form an attached fabric, and furthermore, as a specific polyurethane, 3-methyl-1
, 5-bentanediol and a dicarboxylic acid as soft segments to produce a nonwoven fabric by melt-blown spinning method is proposed in JP-A-1-132858.

[Problem to be solved by the invention]

In conventional melt spinning of thermoplastic polyurethane, the spinning is carried out at a high temperature higher than the dissociation temperature of the urethane bonds in polyurethane, which causes scission of the polyurethane chains, making it impossible to produce fibers and nonwoven fabrics with sufficiently satisfactory performance. As a countermeasure, for example, as proposed in Japanese Patent Publication No. 64-8746, fiber performance is maintained by adding a polyisocyanate compound and spinning to form chain recombination or crosslinking. ing. However, if a highly active compound such as polyisocyanate is used, irregular crosslinking reactions or partial reactions occur, making it impossible to obtain fibers with good quality. Furthermore, polyurethane melts have high viscosity, making it difficult to produce ultrafine fibers with good homogeneity. The present invention uses ultrafine polyurethane that does not cause undesirable irregular crosslinking reactions or partial reactions that occur when polyisocyanates are used, has good thread quality, is highly homogeneous, and has low adhesion. An object of the present invention is to provide a method for producing a nonwoven fabric using a melt-blown spinning method. Furthermore, it is an object of the present invention to provide a polyurethane microfiber nonwoven fabric with excellent photostability and hydrolyzability, low yellowing and oxidative deterioration, and good elastic behavior.

[Means to solve the problem]

The present invention provides an aliphatic or alicyclic diol having an average molecular weight of 600 to 3.00 obtained by the reaction of an aliphatic or alicyclic diol having 8 to 12 carbon atoms and an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid ester.
A thermoplastic polyurethane obtained by reacting 0 polyester diol, an organic diisocyanate mainly composed of aromatic and/or alicyclic diisocyanate, and a chain extender having at least two active hydrogen atoms is added to the spinneret section. This is a method for producing a polyurethane ultrafine fiber nonwoven fabric, which is characterized by spinning the polyurethane ultrafine fiber nonwoven fabric using a melt blown spinning method with a melt viscosity of 400 poise or less. Further, the present invention provides a method for producing an aliphatic or alicyclic diol having an average molecular weight of 600 to 3, 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.
．． 000 polyester diol, aromatic and/or alicyclic diisocyanate, and a chain extender having at least two active hydrogen atoms. This is a method for producing a polyurethane microfiber nonwoven fabric, which comprises adding 0.5 to 3% by weight of at least one compound selected from alcohols and benzotriazoles, and spinning by a melt-blown spinning method. Furthermore, the present invention provides an aliphatic or alicyclic diol having an average molecular weight of 600 to 3, obtained by the reaction of an aliphatic or alicyclic diol having 8 to 12 carbon atoms, and an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid ester.
,000 polyester diol, an organic diincyanate mainly composed of aromatic and/or alicyclic diisocyanates, and a chain extender having at least two active hydrogen atoms, a thermoplastic polyurethane is added with a binder. Adding 0.5 to 3% by weight of at least one compound selected from dophenols and benzotriazoles and 0.05 to 2% by weight of silicone oil having a viscosity of 2 to 150 poise at 30°C, This is a method for producing a polyurethane ultrafine fiber nonwoven fabric, which is characterized by spinning using a melt blown spinning method. The thermoplastic polyurethanes applied to the present invention are polyester diols obtained by condensation polymerization of low-molecular-weight diols and dicarboxylic acids, polylactone diols obtained by ring-opening polymerization of lactams, polyoxyalkylene glycols, polyalkylene carbonate glycols, etc. with average molecular weights. 500~3.0
This is a thermoplastic polyurethane obtained by reacting 00 polymer glycol, an organic diisocyanate, and a low-molecular compound having two active hydrogen atoms. Particularly preferred thermoplastic polyurethanes are aliphatic diols or alicyclic diols having 8 to 12 carbon atoms, such as 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecane. Diol, 1,12-dodecanediol, 2- or 3-methyl-1,7-hebutanediol, 2- or 3-methyl-1,8-octanediol, ω, ω'-dihydroxy-1,4-dimethyl At least one diol selected from linear or side chain aliphatic diols or alicyclic diols such as cyclohexane, and an aliphatic dicarboxylic acid, for example,
Reacting with at least one dicarboxylic acid selected from succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, or esters of these dicarboxylic acids or esters thereof. Obtained average molecular weight 600-3.00
0 polyester diol and an aromatic organic diisocyanate such as phenylene diisocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, inphorone diisocyanate, xylylene diisocyanate, etc. Alternatively, an organic diisocyanate selected from an alicyclic diisocyanate as a main component, and, if necessary, an aliphatic diisocyanate or a diisocyanate having a naphthalene ring, and a low-molecular compound having two active hydrogen atoms, such as a diol. , aminoalcohols are the chain extenders of choice. Then, the polymer diol, organic diisocyanate, and chain extender are selected in 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, this thermoplastic polyurethane has a content of polymer diol, which becomes a soft segment, of 45 to 75% by weight in the composition at the time of producing the polyurethane. Further, the chain extender is a polyurethane polymerized using a chain extender mainly composed of a compound selected from particularly low molecular weight aliphatic diols or inphorone diamines,
The intrinsic viscosity [η] of polyurethane is 0.06 to O. , 12
A polyurethane whose degree of polymerization is adjusted to be in the range of 12/g is preferable from the viewpoint of melt-blowing properties. However, when polyurethane is produced by the melt polymerization method and made into a nonwoven fabric directly by the melt-blown spinning method without taking it out, the intrinsic viscosity [η] at the time of spinning is in the range of 0.05 to 0.10Q/g. Adjust the degree of polymerization. If the soft segment content in polyurethane is less than 4511% by weight, it is good in terms of spinnability and ultra-fine fiber formation, but it is not good in terms of flexibility, stretchability, form stabilization, surface smoothness, etc. of the nonwoven fabric. Undesirable. In addition, when the soft segment content exceeds 75% by weight, it is good in terms of flexibility as a nonwoven fabric, but
Spinnability and microfiber formation deteriorate, making it impossible to obtain a nonwoven fabric with good texture. On the other hand, if the intrinsic viscosity [η] of polyurethane is small, sufficiently fine fibers cannot be obtained, and a nonwoven fabric with fibers of non-uniform thickness will result. Furthermore, when the intrinsic viscosity [η] of polyurethane is large, the melt viscosity becomes high, making it difficult to form a good fiber flow. Next, examples of the hindered phenol compound to be added to the thermoplastic polyurethane include 1.3.5°-tris(4-1-butyl-3-hydroxy-2,6-dimethylpencyl)isocyanuric acid, 1. 3.5- Tris (3
, 5(butyl-4-hydroxybenzyl)isocyanuric acid, triethylene glycol-bis(3-(3-t-butyl-5methyl-4-hydroxyphenyl)propionate), etc. On the other hand, as benzotriazole compounds, For example, 2-(2″-hydroxy-5′-methylphenyl)benzotriazole, 2-(2″-hydroxy5′-t-butylphenyl)benzotriazole,
2(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-L-amylphenyl)benzotriazole, 2-(2'-di-t-butylphenyl)benzotriazole, 'hydroxy-4'-octoxyphenyl)benzotriazole, 2-(2'-hyF roxy-3'-(3', 4", 5", 6"tetrahydrophthalimidomethyl-5'-methylphenyl)benzotriazole These compounds are added to the polyurethane before it is melted or spun.The amount added is in the range of 0.5 to 3% by weight based on the thermoplastic polyurethane.These additives In order to prevent heat-molten polyurethane from dissociating and causing undesirable side reactions, the action of the additive is to actively react with the dissociated part of the active group of the additive and stabilize it. The objective is to provide the additive with the effect of inhibiting oxidation or photodeterioration.Therefore, if the amount of additive added is small,
The dissociated portions of the polyurethane are sufficiently blocked and cannot be stabilized. Moreover, if the amount added is large, the additive will rather cause an undesirable side reaction in the polyurethane, which will deteriorate the performance of the polyurethane. Furthermore, in the present invention, silicone oil is added to the polyurethane at any stage before spinning in order to improve the spinnability and stringiness of the polyurethane and to form a sufficiently fine fiber stream. The silicone oil used in the present invention is a compound that is inert to molten polyurethane, does not increase the vapor pressure of the molten polyurethane system, and has a viscosity in the range of 2 to 150 poise at 30°C; For example, an oily substance selected from compounds such as dimethylpolysiloxane, methylphenylpolysiloxane, and other heat-resistant general silicone oils is added in an amount of 0.05 to 2% by weight based on the polyurethane. Next, the melt blown spinning method of polyurethane composition is
By spinning at a spinning temperature in the range of 230 to 280°C, a temperature with a melt viscosity of 400 poise or less at the spinneret, and a carrier gas pressure (gauge pressure) of 0.5 to 5 kg/cm, an average fiber diameter of 10 Ultra-fine fibers of micron size or less can be obtained, and a fiber stream with good uniformity can be formed. By collecting this fiber stream in a sheet shape on a conveyor net, even if it is wide, it can be made with good uniformity. Polyurethane microfiber nonwoven fabric can be obtained.Increasing the spinning temperature lowers the melt viscosity of the polyurethane composition and improves the spinnability, but the dissociation of urethane bonds increases and the resulting nonwoven fabric has poor physical properties. It is easy to become
In addition, stains occur around the spinneret, resulting in decreased spinnability. If the spinning temperature is lowered, dissociation will be reduced, but the melt viscosity will increase, making it impossible to obtain good ultrafine fibers. Therefore, the melt viscosity at the spinneret is preferably in the range of 400 poise or less. The method for producing a polyurethane ultrafine fiber nonwoven fabric of the present invention has good fluidity of the molten polyurethane and good spinnability of the spun polyurethane fiber, so it can be made sufficiently ultrafine, and the fiber flow is less likely to stick together. Forms a fiber stream with good dispersibility. The polyurethane microfiber nonwoven fabric thus obtained has good homogeneity. Furthermore, a nonwoven fabric product with high strength and elongation can be obtained with less side reactions due to polyurethane dissociation and thermal decomposition. Furthermore, it is a nonwoven fabric that has long-lasting oxidation resistance, light deterioration resistance, and hydrolysis resistance. The polyurethane ultrafine fiber nonwoven fabric obtained in the present invention is useful for bandages, base fabrics for Supporter-1 patch materials, training wear/training pants, bands, base materials for leather-like sheets, and the like.

[Effect]

When thermoplastic polyurethane is melt-spun using the melt-blown method, it is exposed to high-temperature air for a relatively longer period of time than in normal spinning methods, so activated parts such as dissociated parts formed during melting can cause undesirable side reactions. . The activated portion of the polyurethane is blocked by the hindered phenol and/or benzotriazole added to the polyurethane, thereby inhibiting side reactions and stabilizing the polyurethane. Furthermore, the addition of silicone oil improves the fluidity of the molten polyurethane, improves the spinnability of the spun polyurethane fibers, makes it possible to make them sufficiently fine, and further reduces the stickiness of the fiber flow, improving dispersibility. can be increased.

【Example】

Next, embodiments of the present invention will be explained using specific examples, but the present invention is not limited to these examples. Note that parts and percentages in the examples are by weight unless otherwise specified. Further, the intrinsic viscosity [η] of the polymer of the present invention was determined by dissolving it in N,N' dimethylformamide and measuring it at a temperature of 30°C using a capillary viscometer, and the intrinsic viscosity [η] was determined by the following formula. η,, m (t-to)/lo-(t/1o)-1 [η
)-Jimηhe/C where t is the solution flow time (seconds), to is the solvent flow time (seconds), and C is the polymer concentration (g/Q). It was determined by measuring the pressure at the mouthpiece, the diameter of the discharge port, and the discharge amount. Example 1 Poly 2-methyl-1,8-octane adipate glycol having an average molecular weight of 2,000 obtained by condensation polymerization of 2-methyl 1,8-octanediol and adipic acid was used as a polymer diol component, and polymer diol 1 A composition containing mol % (soft segment content 61%), 4 mol % of 4.4'-diphenylmethane diisocyanate, and 3 mol % of 1.4-butylene glycol was polymerized by a melt polymerization method to obtain an intrinsic viscosity [η) = 0. .107 (2/g polyurethane C
I) was obtained. After melt polymerization, this polyurethane [I] was taken out as a strand, cut, and pelletized. To this polyurethane pellet, 1.3.5-tris (4-t
A polyurethane composition to which 1.3% of -butyl-3-hydroxy-2,6-dimethylbenzyl)incyanuric acid and 1% of dimethylpolysiloxane having a viscosity of 3.8 poise at 30°C is melted in an extruder, A melt-blowing machine was installed with a melt-blowing die equipped with a nozzle part in which discharge holes with a diameter of 0.3 mm were arranged in a row at 1-mm intervals, and a melt-blowing die with gas jetting slits of a width of 0.25 mm on both sides. The fibers are spun under the following conditions: melt viscosity at the spindle is 390 poise), conveying air temperature is 290°C, and air pressure is 2.5 kg/cm. Collected on a net with an average basis weight of 100 g/m
A melt-blown ultrafine fiber nonwoven fabric (1) was obtained. This polyurethane has good spinnability and can form ultrafine fibers with good uniformity, and the average fiber diameter is about 7.
It consisted of ultrafine fibers of 6 microns. In addition, the intrinsic viscosity [η] of polyurethane after spinning is 0.089Q/
It was g. Comparative Example 1 Spinning was carried out under the same conditions as in Example 1 except that the spinning temperature was 230° C. (melt viscosity at the spinneret part was 550 poise). As a result, the spinnability was poor, and the polyurethane did not form ultrafine fibers but formed a non-uniform deposit. Comparative Example 2 The polyurethane [■] obtained in Example 1 was spun by a melt-blown method under the conditions of Example 1 without adding any additives. As a result, the nonwoven fabric had poor spinnability, irregular fiber flow, and uneven deposition, resulting in poor uniformity. In addition, the average fiber diameter is distributed in the range of approximately 5.3 microns for thin fibers and approximately 18.2 microns for thick fibers.
;. Furthermore, the intrinsic viscosity [η] of polyurethane after spinning is 0.
．． 066+2/g, indicating a large decrease in viscosity. Comparative Example 3 A polyurethane composition obtained by adding 1% dimethylpolysiloxane having a viscosity of 3.8 poise at 30°C to the polyurethane (1) obtained in Example 1 was melted in an extruder, and melt blown under the conditions of Example 1. It was spun using the method. As a result, the spinnability and fiber flow formation properties were relatively good, the ultrafine fiber flow was well deposited, and the average fiber diameter was about 8.2 microns. However, the intrinsic viscosity [η] of the polyurethane after spinning was 0.0711/g, which was a large decrease in viscosity. Example 2 2-methyl l,3-octanediol (30s) and l,
A polymer diol is prepared from poly2-methyl-1,8-octane/1,9-nonane/adipate glycol with an average molecular weight of 2,000 obtained by condensation polymerization of a mixed diol of 9-nonanediol (70 parts) and adipic acid. As a component, polymer diol 1 mol% (soft segment 55.4%),
4.4'-diphenylmethane diisocyanate 5 mol%
A composition containing 4 mol% of l,4-butylene glycol was polymerized by a melt polymerization method to obtain an intrinsic viscosity [η)-0,097Q/g.
Polyurethane (II) was obtained. This polyurethane (1
After melt polymerization, 1) was taken out as a strand, cut, and pelletized. 1.3 for this polyurethane pellet
．． 5-Tris(4-t-butyl-3-hydroxy-2
,6-dimethylbenzyl)incyanuric acid 1.0%, 2
A polyurethane composition containing 1.0% (2'-hydroxy-3'',5'-di-L-butylphenyl)benzotriazole and 1% dimethylpolysiloxane having a viscosity of 3.8 poise at 30°C is melted in an extruder. The fibers were spun using the melt-blown method under the same conditions as in Example 1, and the ultrafine fiber stream was collected on the net of a collector to obtain an average basis weight of 150.
g/m" melt-blown ultrafine fiber nonwoven fabric (2) was obtained. The results showed that the polyurethane had good spinnability and spinnability, and it was possible to form a flow of ultrafine fibers with good uniformity. It consists of ultrafine fibers with an average fiber diameter of approximately 7.4 microns, and the intrinsic viscosity of polyurethane after spinning is [
η] was 0.091Q/g. In addition, this nonwoven fabric was subjected to a hydrolysis resistance test using a jungle tester at a temperature of 70°C and a humidity of 95%, and the intrinsic viscosity [η] after 15 days was 0.0534/g. It was also excellent in the light resistance test. One side of this nonwoven fabric was embossed with a belt embossing machine that engraved an uneven pattern at 135°C, and the fibers were partially adhered in a pattern. The obtained nonwoven fabric had good elasticity, was flexible, had good skin adhesion, and was useful as a supporter for joints. Example 3 Poly 1.0 with an average molecular weight of 2.000. Intrinsic viscosity [η) obtained by polymerizing by melt polymerization with a composition of 1 mol% to-decane adipate glycol, 5 mol% diphenylmethane diisocyanate, and 4 mol% 2-methyl-1,5-pentane glycol [η) -0, Using 092Q/g of polyurethane, 1.0% of triethylene glycol-bis(3-(3-t-butyl-5-methyl-4-hydroxyphenyl)glopionate), 2-(2'-hydroxy-5'- 1-
A polyurethane m-acid obtained by adding 1.0% of (butylphenyl) benzotriazole was spun using the same melt-blowing apparatus as in Example 1 at a spinning temperature of 250°C and a conveying air temperature of 2.
Spun at 90'C and air pressure of 2.3Kg/cm'', the spun ultrafine fiber stream was collected on the net of a collector to obtain a melt-blown ultrafine fiber nonwoven fabric (with an average basis weight of 75g/-).
3) was obtained. The intrinsic viscosity [η] of the polyurethane after spinning was 0.08312/g, and excellent results were obtained in hydrolysis resistance and light resistance tests. Embossing was performed on the negative side of this ultrafine fiber nonwoven fabric (3) using a belt embossing machine with a smooth surface at 135°C to partially adhere the fibers. The obtained nonwoven fabric was stretchable, flexible, had good skin adhesion, and had good drug spreadability, and was suitable as a base material for a patch.

【Effect of the invention】

The method for producing a polyurethane ultrafine fiber nonwoven fabric of the present invention has good fluidity of the molten polyurethane and good spinnability of the spun polyurethane fiber, so it can be made sufficiently ultrafine, and the fiber flow is less likely to stick together. Forms a fiber stream with good dispersibility. The polyurethane microfiber nonwoven fabric thus obtained has good homogeneity. Furthermore, a nonwoven fabric product with high strength and elongation can be obtained with less side reactions due to polyurethane dissociation and thermal decomposition. Furthermore, it is a nonwoven fabric that has long-lasting oxidation resistance, light deterioration resistance, and hydrolysis resistance.

Claims (3)

[Claims] (1) A polyester diol with an average molecular weight of 600 to 3,000 obtained by the reaction of an aliphatic or alicyclic diol having 8 to 12 carbon atoms and an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid ester, and an aromatic and/or Alternatively, a thermoplastic polyurethane obtained by reacting an organic diisocyanate mainly consisting of an alicyclic diisocyanate with a chain extender having at least two active hydrogen atoms is melt-blown spun with a melt viscosity of 400 poise or less at the spinneret. 1. A method for producing a polyurethane ultrafine fiber nonwoven fabric, which is characterized by spinning by a method. (2) A polyester diol with an average molecular weight of 600 to 3,000 obtained by the reaction of an aliphatic or alicyclic diol having 8 to 12 carbon atoms and an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid ester, and an aromatic and/or Alternatively, a thermoplastic polyurethane obtained by reacting an organic diisocyanate mainly composed of alicyclic diisocyanate with a chain extender having at least two active hydrogen atoms, and at least one selected from hindered phenols and benzotriazoles. A method for producing a polyurethane microfiber nonwoven fabric, which comprises adding 0.5 to 3% by weight of one type of compound and spinning the fabric by a melt-blown spinning method. (3) A polyester diol with an average molecular weight of 600 to 3,000 obtained by the reaction of an aliphatic or alicyclic diol having 8 to 12 carbon atoms and an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid ester, and an aromatic and/or Alternatively, a thermoplastic polyurethane obtained by reacting an organic diisocyanate mainly composed of an alicyclic diisocyanate with a stretching agent having at least two active hydrogen atoms, and at least one selected from hindered phenols and benzotriazoles. 0.5 to 3% by weight of one type of compound and 0.05% of silicone oil with a viscosity of 2 to 150 poise at 30°C.
A method for producing a polyurethane ultrafine fiber nonwoven fabric, which comprises adding ~2% by weight of polyurethane fibers and spinning the fabric by a melt-blown spinning method.