JP2004307833A - Thermoplastic polyurethane elastomer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a thermoplastic urethane elastomer excellent in heat resistance and mechanical strengths and having good cold resistance and flexing durability. <P>SOLUTION: This thermoplastic urethane elastomer (I) is produced by reacting a diol (A) having 1000-5000 number average molecular weight with a diisocyanate (B) and a chain extender (C) having 50-300 number average molecular weight. Here, the whole or a part of the chain extender (C) comprises a chain extender (C1) having a base (a) with a carboxylate group or its monovalent cation and/or a base (b) with a sulfonate group or its monovalent cation in the molecule, and a carboxylate anion group (a') and/or a sulfonate anion group (b') of the elastomer (I) are/is ionically crosslinked each with a multivalent metal cation (e). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to novel polyurethane elastomers having improved thermal properties.
More specifically, it is a polyurethane elastomer (ionomer) excellent in mechanical properties and heat resistance, having a hard segment in which a carboxyl group and / or a sulfonic acid group in a molecule is partially ion-crosslinked with a polyvalent metal. For example, it is used for hole joints and dust covers of automobiles, electric wires and cables, and the like.

A thermoplastic polyurethane elastomer is produced by reacting a compound having an isocyanate group (NCO) with a diol and a chain extender, is excellent in repeated bending durability, cold resistance, and the like, and is extremely useful industrially.
However, these polyurethane elastomers have insufficient physical properties such as heat resistance due to thermal properties derived from urethane bonds.

  On the other hand, in order to improve thermal properties such as heat resistance, there are those using 1,5-naphthalenediisocyanate as a diisocyanate component. Further, urethane elastomers are used without using a reaction accelerator which causes a decrease in heat resistance. It is possible to combine (Patent Document 1).

JP-A-11-279255

However, although the urethane elastomer has improved heat resistance, it has a problem in that cold resistance and flex fatigue resistance are insufficient.
An object of the present invention is to provide a thermoplastic urethane elastomer characterized by having excellent cold resistance, bending fatigue resistance, mechanical properties at room temperature, and heat resistance, and a method for producing the same.

The present inventors have intensively studied to solve the above-mentioned problems, and as a result, have reached the present invention.
That is, the present invention provides a thermoplastic polyurethane elastomer in which an anionic group is ionically crosslinked with a polyvalent metal cation in a hard segment;
In a polyurethane elastomer (I) obtained by reacting a diol (A) having a number average molecular weight of 1,000 to 5,000, a diisocyanate (B) and a chain extender (C) having a number average molecular weight of 50 to 300, a carboxyl group or a monovalent cation thereof A chain extender (C1) having a salt group (a) and / or a sulfonic acid group or a salt group (b) thereof with a monovalent cation in the molecule as at least a chain extender (C), and The carboxylate anion group (a ′) and / or sulfonic acid anion group (b ′) derived from (C1) in the hard segment of (I) is formed by ionic crosslinking with the polyvalent metal cation (e). Thermoplastic polyurethane elastomers;
And an NCO-terminated polyurethane prepolymer obtained by reacting a diol (A) having a number average molecular weight of 1,000 to 5,000 with a diisocyanate (B) to form a carboxyl group or a salt group (a) with a monovalent cation thereof and / or the sulfone After at least a chain extension reaction is carried out with a chain extender (C1) having an acid group or a salt group (b) thereof with a monovalent cation in the molecule, a carboxylate anion group (a) derived from (C1) in the hard segment ') And / or a sulfonate anion group (b') is ion-crosslinked with a polyvalent metal compound.

  The thermoplastic urethane elastomer of the present invention has the performance of being particularly excellent in heat resistance and mechanical strength while maintaining cold resistance and bending fatigue resistance.

In the present invention, the chain extender (C1) is a carboxyl group (COOH) and / or a sulfonic acid group (SO ₃ H), or a salt group thereof (—COO ⁻ M ⁺ , −) with a monovalent metal cation. SO ₃ ^- M ⁺⁾ and has in a molecule, a further two compounds containing a hydroxyl group or an amino group as the active hydrogen, preferably introduced in combination with the following chain extender (C2) to the hard segment of the polyurethane After that, by reacting with the polyvalent metal-containing compound (E), a thermoplastic elastomer which is ionically crosslinked with the polyvalent metal cation, preferably partially ionically crosslinked is obtained.
Here, in the group (a) of a salt with a carboxyl group or its monovalent cation and the group (b) of a salt with a sulfonic acid group or its monovalent cation, it reacts with (E) to form a polyvalent metal cation and ionic crosslinking. The proportion is preferably 20 to 100 mol%, more preferably 30 to 80 mol%.
Then, the heat resistance of the molded body formed from the thermoplastic urethane elastomer by ionic cross-linking with the polyvalent metal cation, preferably by partial ionic cross-linking, the mechanical properties at room temperature are particularly excellent, and various physical properties such as cold resistance are also obtained. The effect of being able to hold is obtained.

  In the present invention, the chain extender (C2) has both a carboxyl group or a salt group thereof with a monovalent cation (a) and a sulfonic acid group or a salt group thereof with a monovalent cation (b). A diol having a number average molecular weight of preferably 50 to 300, more preferably 50 to 150 from the viewpoint of mechanical strength, which is a known chain extender which is not contained therein and is usually used as a chain extender in a polyurethane elastomer. (C21), a diamine (C22) having a number average molecular weight of preferably 50 to 300 and more preferably 50 to 150 from the viewpoint of mechanical strength can be used. Of these, diol (C21) is preferred.

Specific examples of (C21) include aliphatic diols [ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, propylene glycol, Neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,2-, 1,3- or 2,3-butanediol, etc.]; alicyclic diol [1,4-bis (hydroxymethyl) cyclohexane, m- or p-xylylene glycol; ethylene oxide (hereinafter abbreviated as EO) or propylene oxide (hereinafter abbreviated as PO) adduct of bisphenol A (molecular weight 50 to 300) Etc.] and mixtures of two or more of these.
Of these, preferred are ethylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and an EO or PO adduct of bisphenol A.

Specific examples of (C22) include, for example, aromatic diamines, aliphatic diamines, alicyclic diamines, and the like, and mixtures of two or more thereof.
Examples of the aromatic diamine include 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) biphenyl, and , 4′-bis (4-aminophenoxy) benzene, 1,3′-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 3,4-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-methylene-bis (2- Chloroaniline), 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl Phenyl sulfide, 2,6′-diaminotoluene, 2,4-diaminochlorobenzene, 1,2-diaminoanthraquinone, 1,4-diaminoanthraquinone, 3,3′-diaminobenzophenone, 3,4-diaminobenzophenone, 4,4 '-Diaminobenzophenone, 4,4'-diaminobibenzyl, R (+)-2,2'-diamino-1,1'-binaphthalene, S (+)-2,2'-diamino-1,1'- Binaphthalene, 1,3-bis (4-aminophenoxy) alkane, 1,4-bis (4-aminophenoxy) alkane, 1,5-bis (4-aminophenoxy) alkane, and other 1, n-bis (4- Aminophenoxy) alkane (n is 3 to 10), 1,2-bis [2- (4-aminophenoxy) ethoxy] ethane, 9,9-bis (4-aminophenyl ) Fluorene, 4,4'-diaminobenzanilide, and the like.
Examples of the aliphatic diamine include 1,2-diaminomethane, 1,4-diaminobutane, tetramethylenediamine, 1,5-diaminopentane, 1,6-diaminohexane, 1,8-diaminooctane, and 1,10-diaminododecane. , 1,11-diaminoundecane and the like.
Examples of the alicyclic diamine include 1,4-diaminocyclohexane, 1,2-diaminocyclohexane, bis (4-aminocyclohexyl) methane, and 4,4′-diaminodicyclohexylmethane.
Among these, aliphatic diamines are preferable, and 1,2-diaminomethane, 1,4-diaminobutane, and tetramethylenediamine are more preferable.

The chain extender (C1) having an acid group or a salt thereof group imparting the properties of the thermoplastic polyurethane elastomer of the present invention in a molecule includes a carboxyl group or a base (a) thereof and a monovalent cation thereof, a sulfonic acid group. Alternatively, a diol (C11) having a number average molecular weight of preferably from 50 to 300, more preferably from 50 to 150 from the viewpoint of mechanical strength, containing a base (b) with a monovalent cation and a combination thereof in the molecule is more preferable. Diamine (C12) having an average molecular weight of preferably 50 to 300 and more preferably 50 to 150 from the viewpoint of mechanical strength can be used.
The carboxylate anion group (a ') and the sulfonic acid anion group (b') are the respective anion groups of (a) and (b), and these anion groups are further added after the urethane reaction is completed. The cations derived from the polyvalent metal-containing compound (E) are ionically cross-linked with all, preferably partially.

  The group of the salt of a carboxylic acid or a sulfonic acid with a monovalent cation contained in the chain extender (C1) is a monovalent alkali metal salt or an ammonium salt of a carboxylic acid or a sulfonic acid. Here, when a divalent metal such as an alkaline earth metal or a polyvalent metal salt is used as a chain extender, the polyurethane is apt to gel, and (C1) contains a divalent metal such as an alkaline earth metal. Or polyvalent metal salts are not included.

  As specific examples of (C1), 2,2-dialkanolpropionic acid represented by the following general formula (1) or a salt thereof; 2,4-dialkanolbenzenesulfonic acid represented by the formula (2) or a salt thereof N, N-bis (2-hydroxyalkyl) -2-aminoalkanesulfonic acid represented by the formula (3) or a salt thereof; dialkanol sulfamic acid represented by the formula (4) or a salt thereof; .

In the formula, M ⁺ is a monovalent alkali metal ion, ammonium ion or proton; R is an alkylene group having 1 to 8, preferably 3 to 6 carbon atoms; R ′ is a hydrogen atom or 1 to 3 carbon atoms, preferably R ″ is an alkylene group having 1 to 8, preferably 3 to 6 carbon atoms; Ar represents a trivalent aromatic hydrocarbon group.

Among the compounds represented by these formulas (1) to (4), preferred specific examples include 2,2-dimethylolpropionic acid (the salt thereof), 2.4-diethanolbenzenesulfonic acid (the salt thereof), N, N, bis-2-hydroxyethyl-2aminoethanesulfonic acid (salt thereof), diethanolsulfamic acid (salt thereof) and the like.
Of these, more preferred are 2,2-dimethylolpropionic acid, its sodium salt, potassium salt, and lithium salt; N, N, bis-2-hydroxyethyl-2aminoethanesulfonic acid, its sodium salt and its potassium salt, It is a lithium salt.

The chain extender (C) used in the present invention contains a chain extender (C1), and preferably also contains (C2).
The content of (C1) based on the total weight of the chain extender (C2) and the chain extender (C1) is preferably 5 to 100% by weight, more preferably 5 to 90% by weight, and most preferably 20% by weight. -60% by weight, very preferably 25-45% by weight. If it is 5% by weight or more, the heat resistance is sufficiently improved, and if it is 90% by weight or less, sufficient thermoplasticity can be obtained.

  The content of (C1) is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, based on the polyurethane elastomer (I). Further, the content is preferably 10% by weight or less, more preferably 5% by weight or less, and most preferably 2% by weight or less from the viewpoint of the flexibility of the resin itself.

  The polyvalent metal cation (e) of the present invention is a metal cation having a valence of 2 to 4, and is a metal belonging to Group 2, 4, 8, 11, 12, or 13 or a combination thereof. . Specific examples include copper, barium, magnesium, calcium, iron, zinc, aluminum, and titanium. Preferred among these are zinc, aluminum and titanium.

  The thermoplastic urethane elastomer (I) of the present invention comprises a diol (A) having a number average molecular weight of 1,000 to 5,000, a diisocyanate (B), a chain extender (C2) having a number average molecular weight of 50 to 800, and a carboxyl group or one thereof. Thermoplastic polyurethane elastomer obtained by reacting a chain extender (C1) having a salt group (a) with a valent cation and / or a sulfonic acid group or its salt group (b) with a monovalent cation in the molecule It is.

  Examples of the diol (A) having a number average molecular weight of 1,000 to 5,000 in the present invention include polyester diol (A1) and polyester diol (A2).

  Examples of the polyester diol (A2) include a condensation polymer of a low molecular weight diol with a dicarboxylic acid or an ester-forming derivative thereof [acid anhydride, lower alkyl (1 to 4 carbon atoms) ester, acid halide, etc.]; Ring-opened polymers of lactone monomers with diols as initiators; and mixtures of two or more of these.

  As the above polyether diol (A1), for example, a compound having two hydroxyl groups such as a low molecular weight diol or a dihydric phenol is obtained by blocking or randomizing an alkylene oxide having 2 to 5 carbon atoms (hereinafter abbreviated as AO). An added compound may be mentioned. Of these, preferred are those obtained by adding AO to low molecular weight diols, and more preferred are polytetramethylene glycol (PTMG) obtained by adding 1,4-butylene oxide to aliphatic diols.

  Examples of the polyester diol (A2) include a condensation polymer of a low molecular weight diol with a dicarboxylic acid or an ester-forming derivative thereof [acid anhydride, lower alkyl (1 to 4 carbon atoms) ester, acid halide, etc.]; Ring-opened polymers of lactone monomers with diols as initiators; and mixtures of two or more of these.

  Of these (A), preferred is polyether diol (A1), more preferred is polyether diol obtained by adding AO to low molecular weight diol, and particularly preferred is polytetramethylene glycol.

  The number average molecular weight of (A) is generally from 1,000 to 5,000, preferably from 1,000 to 4,000, and more preferably from 1500 to 3,500, from the viewpoint of elongation and strength of the elastomer.

As the diisocyanate (B) of the present invention, for example,
(1) Aliphatic diisocyanates having 2 to 18 carbon atoms (excluding carbon in the NCO group, the same applies hereinafter) [ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethyl Hexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylcaproate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanate Natohexanoate, etc.];
(2) Alicyclic diisocyanate having 4 to 15 carbon atoms [isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis (2-isocyanatoethyl) -4-cyclohexene and the like];
(3) C6-C14 aromatic diisocyanate [1,3- and / or 1,4-phenylene diisocyanate, 2,4- and / or 2,6-tolylene diisocyanate (TDI), crude TDI, 4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl -4,4'-diisocyanatodiphenylmethane, crude MDI, 1,5-naphthylene diisocyanate, etc.];
(4) C8-C15 araliphatic diisocyanates [m- and / or p-xylylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI) and the like];
(5) Modified products of these diisocyanates (modified diisocyanates having a carbodiimide group, uretdione group, uretoimine group, urea group, etc.);
And mixtures of two or more of these (1) to (5).
Among these, preferred are (2) alicyclic diisocyanate, (3) aromatic diisocyanate, and (4) araliphatic diisocyanate, and particularly preferred are IPDI, hydrogenated MDI, MDI, XDI and TMXDI.

As the thermoplastic polyurethane elastomer of the present invention, a polymer having a repeating unit represented by the following general formula (5) is preferable.
In the formula, A is a residue obtained by removing two OH from the diol (A), B is a residue obtained by removing two NCOs from the diisocyanate (B), Y is O or NH, and C2 is the chain extender ( A residue obtained by removing two hydroxyl groups or amino groups from C2), X is O or NH, C1 is two chains or two amino groups removed from the chain extender (C1), and COO ⁻ M ⁺ or SO ₃ ⁻ M A residue excluding a ⁺ group, Z ⁻ is COO ⁻ or SO ₃ ⁻ , En ⁺ is a polyvalent metal ion, p, q, and r are integers of 5 to 80, n is an integer of 2 to 4, The bonding mode of the three repeating units may be block or random.

The number average molecular weight of the urethane elastomer of the present invention is usually from 10,000 to 200,000, preferably from 20,000 to 100,000. When the number average molecular weight is 10,000 or more, the strength of the molded body is obtained, and when it is 200,000 or less, the melt viscosity becomes low and the moldability is good.
The number average molecular weight can be measured by gel permeation chromatography (GPC) such as HLC-8220 (manufactured by Tosoh Technosystem Co., Ltd.) using dimethylformamide as a solvent and polystyrene resin as a molecular weight calibration reagent. it can.

The urethane elastomer of the present invention is thermoplastic. For example, the melt flow rate (g / 10 minutes, measurement conditions: 230 ° C., excess weight 2.16 kg) is preferably 0.1 to 10, more preferably 0.5 to 10. ~ 5.
The hardness (measured by Shore A hardness according to JIS K6301) of the urethane elastomer of the present invention is preferably 30 to 100, and more preferably 50 to 80.
The softening temperature (° C., as measured according to JIS K7206) of the urethane elastomer of the present invention is preferably 145 to 220, and more preferably 165 to 195.

Next, a method for producing the urethane elastomer of the present invention will be described below.
The urethane elastomer of the present invention comprises an NCO-terminated polyurethane prepolymer obtained by reacting a diol (A) having a number average molecular weight of 1,000 to 5,000 with a diisocyanate (B) to form a carboxyl group or a salt group thereof with a monovalent cation (a). ) And / or at least a chain elongation reaction with a chain extender (C1) having a sulfonic acid group or a salt group thereof (b) with a monovalent cation in the molecule, followed by a reaction derived from (C1) in the hard segment. The carboxylate anion group (a ′) and / or the sulfonic acid anion group (b ′) can be obtained by ionic crosslinking, preferably partial ionic crosslinking, with a polyvalent metal compound.
Further, the urethane elastomer of the present invention is preferably obtained by subjecting an NCO-terminated polyurethane prepolymer obtained by reacting (A) and (B) to a chain extension reaction with a chain extender (C2) and a chain extender (C1). The carboxylate anion group (a ′) and / or sulfonic acid anion group (b ′) derived from (C1) in the hard segment can be obtained by ionic crosslinking, preferably partial ionic crosslinking, with a polyvalent metal compound.

Known production methods for obtaining the urethane elastomer of the present invention include a prepolymer method and a one-shot method.
The prepolymer method is a two-step method in which a diisocyanate and a polyol are reacted in an excess of diisocyanate to produce an isocyanate (NCO) -terminated prepolymer, and the elastomer is formed with a chain extender.
The one-shot method is a method in which a diisocyanate, a polyol and a chain extender are mixed and stirred at a time in a reactor without casting an NCO-terminated prepolymer, cast into a mold, and then cured by reaction to obtain an elastomer.
Compared with the one-shot method, the prepolymer method generally has higher strength and durability of the obtained molded article, and the prepolymer method is preferable as the method for producing the elastomer of the present invention.

The NCO-terminated prepolymer used in the present invention has a ratio of NCO equivalent of diisocyanate (B) to hydroxyl group (OH) equivalent of polyol (A) having a number average molecular weight of 1,000 to 5,000 (NCO / OH) of 1.2 to 5,000. 5, preferably 1.5 to 3, and the mixture is heated after adding the catalyst (F) if necessary to complete the reaction.
When the NCO / OH ratio is 1.2 or more, the viscosity of the prepolymer is low, and the moldability is good. When the NCO / OH ratio is 5 or less, the obtained elastomer has good elasticity at low temperatures.

  The temperature during production of the NCO-terminated prepolymer is preferably 100 to 200 ° C. When the temperature is 100 ° C. or higher, the polyisocyanate component melts, and the production time is shortened. When the temperature is 200 ° C. or lower, urethane does not thermally decompose and is stable.

Further, the NCO-terminated prepolymer thus obtained is extended with a chain extender (C) to produce a polyurethane elastomer (IA).
The ratio (H / NCO) of the active hydrogen equivalent (excluding the active hydrogen of carboxylic acid and sulfonic acid) of the chain extender to the NCO equivalent is preferably 0.7 to 0.7%. 1, more preferably from 0.8 to 1. When the H / NCO ratio is 0.7 or more, the mechanical properties become good, and when it is 1 or less, the obtained elastomer does not decrease in elasticity at low temperature.
The temperature during the production of the elastomer is preferably 80 to 200 ° C. If the temperature is 80 ° C. or higher, the elastomer melts, and the production time is shortened. When the temperature is 200 ° C. or lower, urethane is not easily thermally decomposed.

  Next, a polyvalent metal-containing compound (E) is added to the polyurethane elastomer (IA) to increase the carboxylate anion group (a ′) and / or sulfonic acid anion group (b ′) derived from (C1) in the hard segment. The polyurethane elastomer (I) can be obtained by partial ion crosslinking with a valent metal compound.

  In order to crosslink the carboxylate anion group (a ') or the sulfonate anion group (b') with the polyvalent metal cation (e) in the hard segment (HS) of the urethane elastomer (I), preferably partially ionic crosslink. It is necessary to react some or all of the carboxylic acid, sulfonic acid, or salt groups thereof with monovalent cations contained in the chain extender (C1) with the polyvalent metal-containing compound (E). is there. Preferably, 20 to 100 mol%, more preferably 30 to 80 mol%, of the carboxylic acid, sulfonic acid, or a salt group thereof with a monovalent cation reacts with (E).

  Examples of the polyvalent metal-containing compound (E) include alkoxides, inorganic salts, and water of at least one polyvalent metal selected from the group consisting of metals of Groups 2, 4, 8, 11, 12, and 13. Oxides and oxides. Specifically, alkoxides, sulfates, hydroxides, carbonates, oxides and the like of polyvalent metals are used. For example, polyvalent metal alkoxides [aluminum isopropoxide, aluminum tributoxide, tetrabutyl titanate], polyvalent metal sulfates [aluminum sulfate, zinc sulfate, magnesium sulfate, titanium sulfate], polyvalent metal hydroxides [ Zinc hydroxide, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, copper hydroxide], carbonates of polyvalent metals [calcium carbonate, barium carbonate, cobalt carbonate, zinc carbonate, magnesium carbonate, manganese carbonate], polyvalent metals [Aluminum oxide, zinc oxide, calcium oxide, magnesium oxide, titanium oxide, iron oxide, copper oxide, manganese oxide]. Of these, alkoxides of polyvalent metals are preferred.

The amount of the polyvalent metal-containing compound (E) varies depending on its valence, and is preferably based on the total molar equivalent of the carboxyl group, carboxylate anion group, sulfonic acid and sulfonic acid anion group contained in the chain extender. Is a molar equivalent ratio of 0.2 to 1.0.
From the viewpoint of the flexibility of the elastomer, it is more preferable to add 0.3 to 0.7 in terms of equivalent ratio.

Examples of the catalyst (F) that can be used as needed for the synthesis of the prepolymer include amines and organometallic catalysts.
Examples of amines include monoamines: triethylamine (TEA), N, N-dimethylcyclohexylamine (DMEDA); diamines: N, N, N'N'-tetramethylethylenediamine (TMEDA), N, N, N 'N'-tetramethylpropane 1,3-diamine (TMPDA), N, N, N'N'-tetramethylhexane-1,6-diamine (TMHMDA); triamines: N, N, N ', N ", N "-pentamethyldiethylenetriamine (PMDETA), N, N, N ', N", N "-pentamethyldipropylene-triamine (PMDPTA), tetramethylguanidine (TMG); cyclic amines: triethylenediamine (TEDA), N, N'-dimethylpiperazine (DMP), N, -methyl, N '-(2dimethylamino) -ethylpiperazine (TMNAEP) N-methylmorpholine (NMMO), N. (N ', N'-dimethylaminoethyl) -morpholine (DMAEMO), 1,2-dimethylimidazole (DMIZ); alcohol amines: dimethylaminoethanol (DMEA), dimethylamino Ethoxyethanol (DMAEE), N, N, N'-trimethylaminoethyl-ethanolamine (TMAEEA), N-methyl-N '-(2-hydroxyethyl) -piperazine (MHEP), N- (2-hydroxyethyl) morpholine (HEMO); ether amines: bis (2-dimethylaminoethyl) ether (BDMEE) and ethylene glycol bis (3-dimethyl) -aminopropyl ether.
Examples of the organometallic catalyst include, for example, stannas octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marcatide, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin marcaptide, dioctyltin thiocarboxylate, phenyl Mercury propionate, lead octenoate and the like can be mentioned.

In addition, you may add a plasticizer, a pigment, and other additives to the thermoplastic polyurethane elastomer of this invention.
In the present invention, a plasticizer, a pigment and other additives may be added during the production of the elastomer.
Examples of the plasticizer include dialkyl phthalate. Examples of the pigment include titanium dioxide. Other additives include antioxidants which are generally used. These additives may be added to the polyol or may be added to the NCO-terminated prepolymer in advance.

EXAMPLES Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited thereto. In the following description, "parts" indicates parts by weight and "%" indicates% by weight.

Example 1
0.5 mol of polytetramethylene glycol (manufactured by Sanyo Chemical Industries) having a number average molecular weight of 2000, 1.1 mol of diphenylmethane diisocyanate (manufactured by Nippon Polyurethane), and 0.1 g of triethylamine as a catalyst were charged into a four-necked flask and reacted. The reaction was carried out at a temperature of 100 ° C. for 6 hours to obtain a prepolymer (I′-1) having isocyanate groups at both ends.
0.1 mol (19.3 g) of N, N, bis-2-hydroxyethyl-2aminoethanesulfonic acid (molecular weight: 193) and 1,4-butanediol (molecular weight: 90) as chain extenders 0.3 mol (27 g) of the mixture was added and reacted at 100 ° C. for 5 minutes. The content of the chain extender containing sulfonic acid groups based on the total weight of the extender is 41.7% by weight.
To this, 0.02 mol of tetrabutyl titanate as a polyvalent metal-containing compound was added, reacted for 5 minutes, ion-crosslinked, and then poured into a mold preheated to 100 ° C. The desired urethane elastomer (I-1) was obtained by allowing the mixture to react in a circulating drier at 100 ° C. for 20 hours. The conversion of the sulfonic acid group with the polyvalent metal calculated from the charged value is 80 mol%.
The number average molecular weight of (I-1) was 35,000.

Example 2
0.5 mol of polytetramethylene glycol having a number average molecular weight of 3000 (manufactured by Sanyo Chemical Industries, Ltd.), 1 mol of diphenylmethane diisocyanate (manufactured by Nippon Polyurethane), and 1 g of triethylamine as a catalyst were charged into a four-necked flask at a reaction temperature of 100 ° C. The mixture was reacted for 6 hours to obtain a prepolymer (I'-2) having isocyanate groups at both terminals.
As a chain extender, 0.1 mol (21.5 g) of sodium N, N, bis-2-hydroxyethyl-2aminoethanesulfonate (molecular weight: 215) and 0.3 mol of 1,4-butanediol are added to this prepolymer. 27 g) was added and reacted at 100 ° C. for 5 minutes. The content of the chain extender containing sulfonic acid groups based on the total weight of the extender is 44.3% by weight.
0.02 mol of aluminum isopropoxide was added thereto, and the mixture was reacted for 5 minutes to ion-crosslink, and then cast into a mold preheated to 100 ° C. The desired urethane elastomer (I-2) was obtained by allowing the mixture to react in a circulating drier at 100 ° C. for 20 hours. The conversion of the sulfonic acid group with the polyvalent metal calculated from the charged value is 60 mol%.
The number average molecular weight of (I-2) was 42,000.

Example 3
0.2 mol (23.8 g) of dimethylolpropionic acid (molecular weight: 119) and 1,6-hexanediol (molecular weight: 118) as a chain extender on the prepolymer (I'-1) obtained in Production Example 1 0.2 mol (23.6 g) of the mixture was added and reacted at 100 ° C. for 5 minutes. The content of the chain extender containing a carboxyl group based on the total weight of the extender is 50.2% by weight.
After adding 0.05 mol of aluminum tributoxide and reacting for 5 minutes to ion-crosslink, the mixture was poured into a mold preheated to 100 ° C. The desired urethane elastomer (I-3) was obtained by allowing the mixture to react in a circulating air dryer at 100 ° C. for 20 hours. The conversion of the carboxyl group with the polyvalent metal calculated from the charged value is 75 mol%.
The number average molecular weight of (I-3) was 39000.

Example 4
0.1 mol (13.1 g) of sodium dimethylolpropionate (number average molecular weight: 131) as a chain extender and 1,4-butanediol 0.1 to the prepolymer (I'-2) obtained in Production Example 2 3 mol (27.0 g) of the mixture was added and reacted at 100 ° C. for 5 minutes. The content of the chain extender containing a carboxyl group based on the total weight of the extender is 32.7% by weight.
After adding 0.03 mol of tetrabutyl titanate and reacting for 5 minutes to perform ion crosslinking, the mixture was poured into a mold preheated to 100 ° C. The desired urethane elastomer (I-4) was obtained by allowing the mixture to react in a circulating drier at 100 ° C. for 20 hours. The conversion of the carboxyl group with the polyvalent metal calculated from the charged value is 100 mol%.
The number average molecular weight of (I-4) was 33,000.

Comparative Example 1
In Production Example 1, a urethane elastomer (I-5) was obtained by reacting with a circulating drier at 100 ° C. for 20 hours after the chain extension reaction without directly performing ion crosslinking.

Comparative Example 2
0.1 mol (19.3 g) of N, N, bis-2-hydroxyethyl-2aminoethanesulfonic acid (molecular weight: 193) as a chain extender was added to the prepolymer (I′-1) obtained in Production Example 1 After a mixture of 0.3 mol (27.0 g) of 1,4-butanediol was added and reacted at 100 ° C. for 5 minutes, the mixture was cast into a mold preheated to 100 ° C. without ion crosslinking. The urethane elastomer (I-6) was obtained by allowing the mixture to react in a circulating drier at 100 ° C. for 20 hours. The content of the chain extender containing sulfonic acid groups based on the total weight of the extender is 41.7% by weight.
The number average molecular weight of (I-6) was 38,000.

Comparative Example 3
To the prepolymer (I'-1) obtained in Production Example 1, 0.2 mol (23.8 g) of dimethylolpropionic acid (molecular weight: 119) as a chain extender and 0.2 mol of 1,6-hexanediol ( 23.6 g) was added and reacted at 100 ° C. for 5 minutes. After 0.2 mol of sodium chloride as a monovalent metal salt was added thereto and reacted for 5 minutes, the mixture was poured into a mold preheated to 100 ° C. The desired urethane elastomer (I-7) was obtained by allowing the mixture to react in a circulating drier at 100 ° C. for 20 hours. The content of the chain extender containing a carboxyl group based on the total weight of the extender is 50.2% by weight.
The number average molecular weight of (I-7) was 40,000.

Comparative Example 4
To the prepolymer (I'-2) obtained in Production Example 2, 0.1 mol (13.4 g) of trimethylolpropane (molecular weight: 134) as a chain extender and 0.3 mol of 1,4-butanediol ( 27.0 g) of the mixture was added, reacted at 100 ° C. for 5 minutes, and poured into a mold preheated to 100 ° C. The desired urethane elastomer (I-8) was obtained by allowing the mixture to react for 20 hours in a circulating drier at 100 ° C. The content of the chain extender containing a carboxyl group relative to the total weight of the extender is 0% by weight.

Comparative Example 5
A three-necked flask was charged with 70 g of fumaric acid and 1700 g of polypropylene glycol having a molecular weight of 4000, and heated to 150 ° C. To this, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, which is an initiator, was added dropwise at a rate of 5 g every 1.5 hours, and a total of 27 g was added in 13 hours to complete the reaction. A carboxylic acid containing polyol was obtained. Further, 40 g of calcium oxide and 100 g of water were added and neutralized to obtain a calcium salt of polypropylene glycol carboxylate (A-5 ′). After the neutralization reaction, water was removed under reduced pressure.
0.5 mol of polypropylene glycol carboxylate (A-5 '), 1.1 mol of diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Co., Ltd.), and 0.1 g of triethylamine as a catalyst were charged into a four-necked flask. The reaction was carried out for an hour to obtain a desired urethane elastomer (I-9). The conversion of the carboxylic acid group with the polyvalent metal calculated from the charged value is 100 mol%.
The number average molecular weight of (I-9) was 44,000.

[Evaluation test]
The urethane elastomers (I-1) to (I-9) obtained in Examples 1 to 4 and Comparative Examples 1 to 5 were evaluated for properties such as room temperature mechanical properties and heat resistance. The results are shown in the table below.

<Shore A hardness>
The Shore A hardness was measured according to JIS K6301. The measurement was performed using an A-type spring hardness tester, and the arithmetic mean at three locations was used as the measured value.

<Melt flow rate (MFR)>
MFR [g / 10 min] was measured according to JIS K7210. The measurement was performed at 230 ° C. and a load of 2.16 kg.

<Breaking strength>
The breaking strength [kgf / cm ² ] was measured according to JIS K6301. The test piece was measured at 25 ° C. using No. 1 piece.

<Elongation at break>
The elongation at break [%] was measured according to JIS K6301. The test piece was measured at 25 ° C. using No. 1 piece.

<Bending test>
The bending test [mm] was measured according to JIS K6301. The measurement was performed three times, and the average of the inferior length was defined as the measured value. Flexural fatigue resistance can be evaluated.

<Low temperature torsion test>
A low-temperature torsion test [° C.] was measured according to JIS K6301. The evaluation was performed using a wire having a torsion constant of 2.81 mN · m / rad. Cold resistance can be evaluated.

<Softening temperature>
The softening temperature [° C.] was measured according to JIS K7206. Using a test piece having a thickness of 5 mm, evaluation was performed by controlling the temperature at a rate of 120 ° C./h. Heat resistance can be evaluated.

As shown in Tables 1 and 2, it is clear that Examples 1-4 have significantly higher softening temperature and breaking strength than Comparative Examples 1-5, and have improved heat resistance and mechanical strength. It is.
In Comparative Example 4 in which a covalent bond of trimethylolpropane was introduced instead of the ionic bond of dimethylolpropionic acid, the mechanical strength such as Shore A hardness and breaking strength was good, but the bending test and the low-temperature torsion test were performed. It is clear that the sample has poor flex fatigue resistance and cold resistance.
From the above, the thermoplastic urethane elastomer of the present invention has a feature that it is particularly excellent in heat resistance and mechanical strength, and at the same time, can maintain cold resistance and bending fatigue resistance.

The thermoplastic polyurethane elastomer of the present invention is wholly or preferably partially crosslinked with a polyvalent metal ion, and has high-performance mechanical properties and improved heat resistance while having cold resistance. It is used in the form of a film, sheet, or molded product, and is particularly advantageously used for a hole joint / dust cover of an automobile, a wire / cable material, and the like.

Claims (13)

A thermoplastic polyurethane elastomer in which an anionic group is ionically crosslinked with a polyvalent metal cation in a hard segment. In a polyurethane elastomer (I) obtained by reacting a diol (A) having a number average molecular weight of 1,000 to 5,000, a diisocyanate (B) and a chain extender (C) having a number average molecular weight of 50 to 300, a carboxyl group or a monovalent cation thereof A chain extender (C1) having a salt group (a) and / or a sulfonic acid group or a salt group (b) thereof with a monovalent cation in the molecule as at least a chain extender (C), and The carboxylate anion group (a ′) and / or sulfonic acid anion group (b ′) derived from (C1) in the hard segment of (I) is ionically crosslinked with the polyvalent metal cation (e). The thermoplastic polyurethane elastomer according to claim 1, wherein The chain extender (C1), and further a chain extender (C2) having neither the group (a) nor the group (b) in the molecule as a chain extender (C); The carboxylate anion group (a ′) and / or sulfonic acid anion group (b ′) derived from (C1) in the hard segment of the polyurethane elastomer (I) is partially ion-crosslinked with the polyvalent metal cation (e). The thermoplastic polyurethane elastomer according to claim 2, wherein: 4. The thermoplastic polyurethane elastomer according to claim 2, wherein the chain extender (C1) is a chain extender represented by at least one selected from the group consisting of the following general formulas (1) to (4).
[Wherein, M ⁺ is a monovalent alkali metal ion, ammonium ion, or proton; R is an alkylene group having 1 to 8 carbon atoms; R ′ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; Ar represents an alkylene group having 1 to 8 carbon atoms; Ar represents a trivalent aromatic hydrocarbon group. ] The thermoplastic polyurethane elastomer according to any one of claims 1 to 4, having a repeating unit represented by the following general formula (5).
Wherein A is a residue obtained by removing two OH from the diol (A), B is a residue obtained by removing two NCOs from the diisocyanate (B), Y is O or NH, and C2 is the chain extender. A residue obtained by removing two hydroxyl groups or amino groups from (C2), X is O or NH, C1 is two chains or two amino groups removed from the chain extender (C1), and COO ⁻ M ⁺ or SO ₃ ^−. A residue excluding the M ⁺ group, Z ⁻ is COO ⁻ or SO ₃ ⁻ , En ⁺ is a polyvalent metal ion, p, q, and r are integers of 5 to 80, n is an integer of 2 to 4, The bonding mode of the three repeating units in the formula may be block or random. ] The said chain extender (C) WHEREIN: Content of (C1) with respect to the total weight of the said chain extender (C2) and the said chain extender (C1) is 5-90 weight%. Thermoplastic polyurethane elastomer. The polyvalent metal cation (e) in the hard segment is at least one divalent to tetravalent cation selected from the group consisting of Group 2, 4, 8, 11, 11, 12 and 13 metal elements; The thermoplastic polyurethane elastomer according to any one of claims 2 to 6, wherein The thermoplastic polyurethane elastomer according to claim 7, wherein the polyvalent metal cation (e) is at least one selected from the group consisting of zinc, aluminum, and titanium. The thermoplastic polyurethane elastomer according to any one of claims 2 to 8, wherein the diol (A) having a number average molecular weight of 1,000 to 5,000 is a polyether diol (A1) and / or a polyester diol (A2). The thermoplastic polyurethane elastomer according to any one of claims 1 to 9, which is used as a covering material for electric wires and cables. An NCO-terminated polyurethane prepolymer obtained by reacting a diol (A) having a number average molecular weight of 1,000 to 5,000 with a diisocyanate (B) is converted into a carboxyl group or a salt group (a) with a monovalent cation thereof and / or a sulfonic acid group Alternatively, a carboxylate anion group (a ′) derived from (C1) in the hard segment after at least a chain elongation reaction with a chain extender (C1) having a salt group (b) with a monovalent cation in the molecule. And / or a sulfonic acid anion group (b ′) is ionically cross-linked with a polyvalent metal compound. The NCO-terminated polyurethane prepolymer is prepared by combining the chain extender (C1) and the chain extender (C2) having neither (a) nor (b) in the molecule and having a number average molecular weight of 50 to 300. ), The carboxylate anion group (a ′) and / or sulfonic acid anion group (b ′) derived from (C1) in the hard segment are partially ion-crosslinked with a polyvalent metal compound. The method for producing a thermoplastic polyurethane elastomer according to claim 11, wherein The method for producing a thermoplastic polyurethane elastomer according to claim 11 or 12, wherein the chain extender (C1) is a chain extender represented by at least one selected from the group consisting of the following general formulas (1) to (4).
[Wherein, M ⁺ is a monovalent alkali metal ion, ammonium ion, or proton; R is an alkylene group having 1 to 8 carbon atoms; R ′ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; Ar represents an alkylene group having 1 to 8 carbon atoms; Ar represents a trivalent aromatic hydrocarbon group. ]