JP4567995B2 - Thermoplastic polyurethane elastomer - Google Patents

Description

The present invention relates to a novel polyurethane elastomer with 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 the molecule are partially ionically crosslinked with a polyvalent metal. For example, it is used for automobile hall joints / dust covers, electric wires / cable materials, 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 and is excellent in repeated bending durability, cold resistance, etc., and is extremely useful industrially.
However, these polyurethane elastomers have insufficient physical properties such as heat resistance due to thermal characteristics derived from urethane bonds.

  On the other hand, in order to improve thermal properties such as heat resistance, there are those using 1,5-naphthalene diisocyanate as a diisocyanate component, and urethane elastomer can be used without using a reaction accelerator that causes a decrease in heat resistance. Synthesis is possible (Patent Document 1).

JP-A-11-279255

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

As a result of intensive studies to solve the above-mentioned problems, the present inventors have reached the present invention.
That is, the present invention relates to a polyurethane elastomer (I) obtained by reacting a diol (A) having a number average molecular weight of 1000 to 5000, a diisocyanate (B), and a chain extender (C) having a number average molecular weight of 50 to 300. Chain extender (C1) having a group (a) and / or a salt group (b) of a sulfonic acid group or a monovalent cation thereof, and two hydroxyl groups or amino groups in the molecule ) At least as the chain extender (C), and the carboxylate anion group (a ′) and / or the sulfonate anion group (b ′) derived from (C1) in the hard segment of (I) is a polyvalent metal cation A thermoplastic polyurethane elastomer obtained by ion-crosslinking with (e);
And an NCO-terminated polyurethane prepolymer obtained by reacting a diol (A) having a number average molecular weight of 1000 to 5000 and a diisocyanate (B), a carboxyl group or a salt group thereof with a monovalent cation (a) and / or a sulfonic acid After at least a chain extension reaction with a chain extender (C1) having a number average molecular weight of 50 to 300 having two groups or a group (b) of a salt with a monovalent cation and a hydroxyl group or an amino group in the molecule, In the method for producing a thermoplastic polyurethane elastomer, the carboxylate anion group (a ′) and / or the sulfonate anion group (b ′) derived from (C1) in the hard segment is ion-crosslinked with a polyvalent metal compound. is there.

  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), a group of a salt with these monovalent metal cations (—COO ⁻ M ⁺ , − SO ₃ ^- M ⁺ ) in the molecule and further containing two hydroxyl groups and amino groups as active hydrogens, preferably introduced into the polyurethane hard segment in combination with the following chain extender (C2) After that, by reacting with the polyvalent metal-containing compound (E), a thermoplastic elastomer ionically crosslinked with the polyvalent metal cation, preferably partially ionically crosslinked, is obtained.
Here, in the group (a) of the salt with the carboxyl group or its monovalent cation and the group (b) of the salt with the sulfonic acid group or its monovalent cation, it reacts with (E) to react with the polyvalent metal cation and the ionic bridge The ratio is preferably 20 to 100 mol%, more preferably 30 to 80 mol%.
The molded article formed from a thermoplastic urethane elastomer by ionic crosslinking with a polyvalent metal cation, preferably partial ionic crosslinking, is particularly excellent in heat resistance, mechanical properties at room temperature, and various physical properties such as cold resistance. The effect that it can hold | maintain is acquired.

  In the present invention, the chain extender (C2) is a molecule having both a carboxyl group or a salt group with a monovalent cation (a) and a sulfonic acid group or a salt group with a monovalent cation (b). A chain extender that is not contained in the diol, and is a known one that is usually used as a chain extender in a polyurethane elastomer, and preferably has a number average molecular weight of 50 to 300, more preferably 50 to 150 from the viewpoint of mechanical strength. (C21), 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; bisphenol A ethylene oxide (hereinafter abbreviated as EO) or propylene oxide (hereinafter abbreviated as PO) adduct (molecular weight 50 to 300) Etc.] and mixtures of two or more thereof.
Among these, preferred are ethylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, EO or PO adduct of bisphenol A.

Specific examples of (C22) include aromatic diamines, aliphatic diamines, and alicyclic diamines, and mixtures of two or more of these.
As aromatic diamines, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 1 , 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'-diaminodiphenyl sulfone, 3,4-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-methylene-bis (2- Chloroaniline), 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminodi 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'- 1, n-bis (4- (4-aminophenoxy) alkane, 1,4-bis (4-aminophenoxy) alkane, 1,4-bis (4-aminophenoxy) alkane, 1,5-bis (4-aminophenoxy) alkane, etc. Aminophenoxy) alkane (n is 3 to 10), 1,2-bis [2- (4-aminophenoxy) ethoxy] ethane, 9,9-bis (4-aminopheny) ) Fluorene, 4,4'-diaminobenzanilide, and the like.
Aliphatic diamines 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, 4,4′-diaminodicyclohexylmethane, and the like.
Of 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 salt group imparting the properties of the thermoplastic polyurethane elastomer of the present invention in the molecule is a carboxyl group or a base with a monovalent cation (a), a sulfonic acid group Or the base (b) with the monovalent cation, and the number average molecular weight containing these combinations in the molecule is preferably 50 to 300, more preferably from the viewpoint of mechanical strength, the diol (C11) having a number of 50 to 150, the number A 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 sulfonate anion group (b ′) are the anion groups of (a) and (b), and these anion groups are further added after the urethane reaction is completed. The cation is derived from the cation derived from the polyvalent metal-containing compound (E) entirely, preferably partially ionically crosslinked.

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

  Specific examples of (C1) include 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 formula (3) or a salt thereof; dialkanol sulfamic acid represented by 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 carbon atoms, preferably 3 to 6 carbon atoms; R ′ is a hydrogen atom or 1 to 3 carbon atoms, preferably 1 to 2 alkyl groups; R ″ represents an alkylene group having 1 to 8 carbon atoms, preferably 3 to 6 carbon atoms; Ar represents a trivalent aromatic hydrocarbon group.

Among these compounds represented by the formulas (1) to (4), preferred specific examples include 2,2-dimethylolpropionic acid (its salt), 2.4-diethanolbenzenesulfonic acid (its salt), N, N, bis-2hydroxyethyl-2aminoethanesulfonic acid (its salt), diethanolsulfamic acid (its salt), etc. are mentioned.
Of these, 2,2-dimethylolpropionic acid, its sodium salt, potassium salt, lithium salt; N, N, bis-2hydroxyethyl-2aminoethanesulfonic acid, its sodium salt, potassium salt, Lithium salt.

The chain extender (C) used in the present invention includes a chain extender (C1), and preferably also includes (C2).
The content of (C1) with respect to 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 -60% by weight, very preferably 25-45% by weight. When it is 5% by weight or more, the heat resistance is sufficiently improved, and when it is 90% by weight or less, thermoplasticity is sufficiently obtained.

  Further, (C1) is preferably contained in an amount of 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, which is a metal of Group 2, Group 4, Group 8, Group 11, Group 12 or Group 13, and a combination thereof. . Specific examples include copper, barium, magnesium, calcium, iron, zinc, aluminum, and titanium. Of these, zinc, aluminum, and titanium are preferable.

  The thermoplastic urethane elastomer (I) of the present invention comprises a diol (A) having a number average molecular weight of 1000 to 5000, a diisocyanate (B), a chain extender (C2) having a number average molecular weight of 50 to 800, and a carboxyl group or 1 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 a salt group (b) with a monovalent cation in the molecule It is.

  Examples of the diol (A) having a number average molecular weight of 1000 to 5000 of the present invention include polyester diol (A1) and polyester diol (A2).

  As the polyester diol (A2), a low molecular diol is condensed with a dicarboxylic acid or an ester-forming derivative thereof [an acid anhydride, lower alkyl (carbon number 1 to 4) ester, acid halide, etc.]; A ring-opening polymer of a lactone monomer using a diol as an initiator; and a mixture of two or more thereof.

  As the polyether diol (A1), for example, a low-molecular diol, a divalent phenol or the like containing two hydroxyl groups, a C2-C5 alkylene oxide (hereinafter abbreviated as AO) is blocked or randomly. The added compound can be mentioned. Of these, preferred are those obtained by adding AO to a low molecular diol, and more preferred is polytetramethylene glycol (PTMG) obtained by adding 1,4-butylene oxide to an aliphatic diol.

  As the polyester diol (A2), a low molecular diol is condensed with a dicarboxylic acid or an ester-forming derivative thereof [an acid anhydride, lower alkyl (carbon number 1 to 4) ester, acid halide, etc.]; A ring-opening polymer of a lactone monomer using a diol as an initiator; and a mixture of two or more thereof.

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

  The number average molecular weight of (A) is usually 1000 to 5000, preferably 1000 to 4000, and more preferably 1500 to 3500 from the viewpoints of elongation and strength of the elastomer.

As the diisocyanate (B) of the present invention, for example,
(1) Aliphatic diisocyanate having 2 to 18 carbon atoms (excluding carbon in NCO group, the same shall apply hereinafter) [ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethyl Hexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanate Natohexanoate, etc.];
(2) C4-C15 alicyclic diisocyanate [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, 2, 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) C8-15 araliphatic diisocyanate [m- and / or p-xylylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI), etc.];
(5) Modified products of these diisocyanates (modified diisocyanates having a carbodiimide group, a uretdione group, a uretoimine group, a urea group, etc.);
And a mixture of two or more of (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 NCO from the diisocyanate (B), Y is O or NH, C2 is the chain extender ( C2) a residue obtained by removing two hydroxyl groups or amino groups, X is O or NH, C1 is a group obtained by removing two hydroxyl groups or amino groups from the chain extender (C1), and COO ⁻ M ⁺ or SO ₃ ⁻ M Residue excluding ⁺ 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 10,000 to 200,000, preferably 20,000 to 100,000. When the number average molecular weight is 10,000 or more, the strength of the molded article is obtained, and when it is 200,000 or less, the resultant melt viscosity is low and the moldability is good.
The number average molecular weight can be measured using 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. ~ 5.
The hardness of the urethane elastomer of the present invention (by measurement of Shore A hardness according to JIS K6301) is preferably 30 to 100, more preferably 50 to 80.
The softening temperature (° C., measured according to JIS K7206) of the urethane elastomer of the present invention is preferably 145 to 220, more preferably 165 to 195.

Next, the manufacturing method of the urethane elastomer of this invention is demonstrated 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 1000 to 5000 with a diisocyanate (B), a salt group with a carboxyl group or a monovalent cation (a ) And / or the chain group (b) having a sulfonic acid group or a salt thereof with a monovalent cation at least in a chain extender (C1) in the molecule, and then derived from (C1) in the hard segment The carboxylate anion group (a ′) and / or the sulfonate anion group (b ′) can be obtained by ionic crosslinking, preferably partial ionic crosslinking, with a polyvalent metal compound.
In the urethane elastomer of the present invention, the NCO-terminated polyurethane prepolymer obtained by reacting (A) and (B) is preferably subjected to a chain extension reaction with a chain extender (C2) and a chain extender (C1). The carboxylate anion group (a ′) and / or the sulfonate 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-stage method in which an isocyanate (NCO) -terminated prepolymer is produced by reacting a diisocyanate and a polyol with an excess of diisocyanate, and an elastomer is used as a chain extender.
The one-shot method is a method in which an NCO-terminated prepolymer is not produced, and a diisocyanate, a polyol and a chain extender are mixed and stirred at a time in a reactor, cast into a mold, and then reacted and cured to obtain an elastomer.
The prepolymer method generally has higher strength and durability than the one-shot method, and the prepolymer method is preferred as the method for producing the elastomer of the present invention.

The NCO-terminated prepolymer used in the present invention has a ratio (NCO / OH) of the NCO equivalent of the diisocyanate (B) to the hydroxyl (OH) equivalent of the polyol (A) having a number average molecular weight of 1,000 to 5,000. 5, preferably 1.5 to 3, and after adding the catalyst (F) if necessary, it is heated 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 the production of the NCO-terminated prepolymer is preferably 100 to 200 ° C. When the temperature is 100 ° C. or higher, the polyisocyanate component is melted 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 blending amount of the chain extender (C) is such that the ratio (H / NCO) of the active hydrogen equivalent of the chain extender to the NCO equivalent (excluding the active hydrogen of carboxylic acid and sulfonic acid) is 0.7 to 1, more preferably 0.8 to 1. When the H / NCO ratio is 0.7 or more, the mechanical properties are good, and when it is 1 or less, the elasticity of the obtained elastomer does not decrease at low temperatures.
The temperature during the production of the elastomer is preferably 80 to 200 ° C. When the temperature is 80 ° C. or higher, the elastomer is melted and the production time is shortened. When the temperature is 200 ° C. or lower, urethane is hardly thermally decomposed.

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

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

  As the polyvalent metal-containing compound (E), an alkoxide of at least one polyvalent metal selected from the group consisting of metals of Group 2, Group 4, Group 8, Group 11, Group 12, Group 13 and Group 13, inorganic salt, water An oxide and an oxide are mentioned. Specifically, polyvalent metal alkoxides, sulfates, hydroxides, carbonates, oxides and the like are used. For example, polyvalent metal alkoxide [aluminum isopropoxide, aluminum tributoxide, tetrabutyl titanate], polyvalent metal sulfate [aluminum sulfate, zinc sulfate, magnesium sulfate, titanium sulfate], polyvalent metal hydroxide [ 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 Oxides [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 addition amount of the polyvalent metal-containing compound (E) varies depending on the valence and is preferably relative to the molar equivalent of the total of carboxyl groups, carboxylate anion groups, sulfonic acids and sulfonic acid anion groups 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 in the prepolymer synthesis as needed 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 ′-(2 dimethylamino) -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 ′-(2hydroxyethyl) -piperazine (MHEP), N- (2-hydroxyethyl) morpholine (HEMO); ether amines: bis (2-dimethylaminoethyl) ether (BDMEE), ethylene glycol bis (3-dimethyl) -aminopropyl ether.
Examples of the organometallic catalyst include stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marker peptide, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin marker peptide, dioctyltin thiocarboxylate, phenyl. Examples include mercury propionate and lead octenoate.

In addition, you may add a plasticizer, a pigment, and another additive 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 phthalates. Examples of the pigment include titanium dioxide. Other additives include generally used antioxidants. These additives may be added to the polyol or may be added in advance to the NCO-terminated prepolymer.

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” represents parts by weight and “%” represents% by weight.

Example 1
A polytetramethylene glycol (manufactured by Sanyo Chemical Co., Ltd.) having a number average molecular weight of 2000, 0.5 mol, 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 and reacted The mixture was reacted at a temperature of 100 ° C. for 6 hours to obtain a prepolymer (I′-1) having isocyanate groups at both ends.
In this prepolymer, N, N, bis-2hydroxyethyl-2aminoethanesulfonic acid (molecular weight: 193) 0.1 mol (19.3 g) and 1,4-butanediol (molecular weight: 90) 0 were used as chain extenders. .3 mol (27 g) of the mixture was added and reacted at 100 ° C. for 5 minutes. The content of the chain extender containing a sulfonic acid group with respect to the total weight of the extender is 41.7% by weight.
To this, 0.02 mol of tetrabutyl titanate was added as a polyvalent metal-containing compound, reacted for 5 minutes and ion-crosslinked, and then cast into a mold preheated to 100 ° C. The target urethane elastomer (I-1) was obtained by reacting with a circulating dryer at 100 ° C. for 20 hours. The reaction rate 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
A polytetramethylene glycol (manufactured by Sanyo Chemical Co., Ltd.) having a number average molecular weight of 3000, 0.5 mol, diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Co., Ltd.), 1 mol, and 1 g of triethylamine as a catalyst were charged into a four-necked flask. The mixture was reacted for 6 hours to obtain a prepolymer (I′-2) having isocyanate groups at both ends.
As a chain extender, 0.1 mole (21.5 g) of sodium N, N, bis-2hydroxyethyl-2aminoethanesulfonate (molecular weight: 215) and 0.3 mole of 1,4-butanediol ( 27 g) was added and reacted at 100 ° C. for 5 minutes. The content of the chain extender containing a sulfonic acid group with respect to the total weight of the extender is 44.3% by weight.
To this, 0.02 mol of aluminum isopropoxide was added and reacted for 5 minutes for ion crosslinking, and then cast into a mold preheated to 100 ° C. The target urethane elastomer (I-2) was obtained by reacting with a circulating dryer at 100 ° C. for 20 hours. The reaction rate 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 42000.

Example 3
As a chain extender, 0.2 mol (23.8 g) of dimethylolpropionic acid (molecular weight: 119) and 1,6-hexanediol (molecular weight: 118) were added to 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 with respect to the total weight of the extender is 50.2% by weight.
After 0.05 mol of aluminum tributoxide was added thereto and reacted for 5 minutes to ion-crosslink, it was cast into a mold preheated to 100 ° C. The target urethane elastomer (I-3) was obtained by reacting with a circulating dryer at 100 ° C. for 20 hours. The reaction rate 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) and 1,4-butanediol as a chain extender were added 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 with respect to the total weight of the extender is 32.7% by weight.
To this, 0.03 mol of tetrabutyl titanate was added and reacted for 5 minutes for ion crosslinking, and then cast into a mold preheated to 100 ° C. The target urethane elastomer (I-4) was obtained by reacting with a circulating dryer at 100 ° C. for 20 hours. The reaction rate 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 33000.

Comparative Example 1
In Production Example 1, after the chain extension reaction, the urethane elastomer (I-5) was obtained by reacting for 20 hours in a circulating dryer at 100 ° C. without performing ionic crosslinking as it is.

Comparative Example 2
N, N, bis-2hydroxyethyl-2aminoethanesulfonic acid (molecular weight: 193) 0.1 mol (19.3 g) as a chain extender to the prepolymer (I′-1) obtained in Production Example 1 A mixture of 0.3 mol (27.0 g) of 1,4-butanediol was added and reacted at 100 ° C. for 5 minutes, and then cast into a mold preheated to 100 ° C. without ion crosslinking. The urethane elastomer (I-6) was obtained by reacting with a circulating dryer at 100 ° C. for 20 hours as it was. The content of the chain extender containing a sulfonic acid group with respect to the total weight of the extender is 41.7% by weight.
The number average molecular weight of (I-6) was 38000.

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) and 0.2 mol of 1,6-hexanediol as a chain extender ( 23.6 g) was added and allowed to react at 100 ° C. for 5 minutes. After adding 0.2 mol of sodium chloride which is a monovalent metal salt to this and reacting for 5 minutes, it was cast in a mold preheated to 100 ° C. The target urethane elastomer (I-7) was obtained by reacting with a circulating dryer at 100 ° C. for 20 hours. The content of the chain extender containing a carboxyl group with respect to the total weight of the extender is 50.2% by weight.
The number average molecular weight of (I-7) was 40000.

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

Comparative Example 5
In a three-necked flask, 70 g of fumaric acid and 1700 g of polypropylene glycol having a molecular weight of 4000 were placed and heated to 150 ° C. Here, 5 g of 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, which is an initiator, was dropped 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 polypropylene glycol carboxylic acid calcium salt (A-5 ′). After neutralization, water was removed under reduced pressure.
Polypropylene glycol carboxylic acid calcium salt (A-5 ′) 0.5 mol, diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Co., Ltd.) 1.1 mol, triethylamine 0.1 g as a catalyst were charged into a four-necked flask, reaction temperature 100 ° C., 6 The target urethane elastomer (I-9) was obtained by reacting for a period of time. The reaction rate of the carboxylic acid group calculated from the charged value with the polyvalent metal is 100 mol%.
The number average molecular weight of (I-9) was 44000.

[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 performance such as room temperature mechanical properties and heat resistance characteristics. The results are shown in the table below.

<Shore A hardness>
The Shore A hardness was measured according to JIS K6301. It measured using the A type spring type hardness tester, and the arithmetic average of three places was made into the measured value.

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

<Break strength>
The breaking strength [kgf / cm ² ] was measured according to JIS K6301. The test piece used the No. 1 piece and measured at 25 degreeC.

<Elongation at break>
The elongation at break [%] was measured according to JIS K6301. The test piece used the No. 1 piece and measured at 25 degreeC.

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

<Low temperature torsion test>
The low temperature torsion test [° C.] was measured according to JIS K6301. Evaluation was performed using a wire having a torsional constant of 2.81 mN · m / rad. Can evaluate cold resistance.

<Softening temperature>
The softening temperature [° C.] was measured according to JIS K7206. Using a test piece having a thickness of 5 mm, the temperature was controlled at a heating rate of 120 ° C./h for evaluation. Can evaluate heat resistance.

As shown in Tables 1 and 2, it is clear that Examples 1 to 4 have significantly higher softening temperature and breaking strength than Comparative Examples 1 to 5, and improved performance in heat resistance and mechanical strength. It is.
In Comparative Example 4 in which a covalent bond of trimethylolpropane was introduced instead of an ionic bond of dimethylolpropionic acid, mechanical strength such as Shore A hardness and breaking strength was good, but a bending test and a low-temperature torsion test. It is apparent that the bending fatigue resistance and the cold resistance are inferior.
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, it can maintain cold resistance and bending fatigue resistance.

The thermoplastic polyurethane elastomer of the present invention is wholly or preferably partially crosslinked with polyvalent metal ions, and has improved high-performance mechanical characteristics and heat resistance while maintaining cold resistance. It is used in the form of film, sheet, and molded product, and is particularly advantageously used in automobile hole joints, dust covers, electric wires and cable materials.

Claims (12)

In the polyurethane elastomer (I) obtained by reacting a diol (A) having a number average molecular weight of 1000 to 5000, 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 group (a) and / or a sulfonic acid group or a salt group (b) thereof with a monovalent cation and two hydroxyl groups or amino groups in the molecule. And the carboxylate anion group (a ′) and / or the sulfonate anion group (b ′) derived from (C1) in the hard segment of (I) is ionically crosslinked with the polyvalent metal cation (e). A thermoplastic polyurethane elastomer characterized by comprising: Chain extender (C2) selected from diol (C21) and diamine (C22), which does not have any of the groups (a) and (b) in the molecule. ) As a chain extender (C), and the carboxylate anion group (a ′) and / or the sulfonate anion group (b ′) derived from (C1) in the hard segment of the polyurethane elastomer (I) are polyvalent. 2. The thermoplastic polyurethane elastomer according to claim 1, wherein the thermoplastic polyurethane elastomer is formed by partial ion crosslinking with the metal cation (e). The thermoplastic polyurethane elastomer according to claim 1 or 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; An alkylene group having 1 to 8 carbon atoms; Ar represents a trivalent aromatic hydrocarbon group; ] The thermoplastic polyurethane elastomer according to claim 3, which has a repeating unit represented by the following general formula (5).
[Wherein A is a residue obtained by removing 2 OH from the diol (A), B is a residue obtained by removing 2 NCO 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 hydroxyl groups or amino groups are 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. ] 5. The content of (C1) in the chain extender (C) is 5 to 90 weight percent with respect to the total weight of the chain extender (C2) and the chain extender (C1). 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, Group 4, Group 8, Group 11, Group 12 and Group 13 metal elements. The thermoplastic polyurethane elastomer according to any one of claims 1 to 5. The thermoplastic polyurethane elastomer according to claim 6, 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 1 to 7, wherein the diol (A) having a number average molecular weight of 1000 to 5000 is a polyether diol (A1) and / or a polyester diol (A2). The thermoplastic polyurethane elastomer according to any one of claims 1 to 8, which is used as a coating material for electric wires and cables. An NCO-terminated polyurethane prepolymer obtained by reacting a diol (A) having a number average molecular weight of 1000 to 5000 and a diisocyanate (B) is converted into a carboxyl group or a salt group with a monovalent cation (a) and / or a sulfonic acid group. Alternatively, after the chain extension reaction (C1) having a number average molecular weight of 50 to 300 and having a group (b) of a salt with a monovalent cation and two hydroxyl groups or amino groups in the molecule, A process for producing a thermoplastic polyurethane elastomer, characterized by ion-crosslinking a carboxylate anion group (a ′) and / or a sulfonate anion group (b ′) derived from (C1) in a segment with a polyvalent metal compound. The NCO-terminated polyurethane prepolymer is a diol (C21) that does not have any of the chain extender (C1) and (a) and (b) in the molecule and has a number average molecular weight of 50 to 300 And a chain extender (C2) selected from diamine (C22) and then a carboxylate anion group (a ′) and / or a sulfonate anion group (b ′) derived from (C1) in the hard segment The method for producing a thermoplastic polyurethane elastomer according to claim 10, wherein the polymer is partially ion-crosslinked with a polyvalent metal compound. The method for producing a thermoplastic polyurethane elastomer according to claim 10 or 11, 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; An alkylene group having 1 to 8 carbon atoms; Ar represents a trivalent aromatic hydrocarbon group; ]