JP2013147614A - Polyurethane resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyurethane resin excellent in all expansion/contraction properties of elastic recovery rate, tensile strength and elongation.SOLUTION: The polyurethane resin is obtained by reacting an active hydrogen component (A) with an organic polyisocyanate component (B), the active hydrogen component (A) includes a polyether polyol (a1) having an oxytetramethylene group and a branched ether group (x) represented by general formula (1) as structural units and a polyoxytetramethylene glycol (a2), and a weight ratio of the branched ether group (x) in the polyether polyol (a1) is ≥40 wt.%.

Description

  The present invention relates to a polyurethane resin. More specifically, the present invention relates to a polyurethane resin suitable as a raw material for producing elastic fibers, thermoplastic elastomers, paints, synthetic leather, and the like.

  Polyurethane resins are widely used as raw materials for producing elastic fibers, thermoplastic elastomers, paints, synthetic leathers and the like because of their excellent stretch properties (elastic recovery rate, tensile strength, elongation, etc.). In particular, polyurethane resins using polyoxytetramethylene glycol as a polyol component are excellent in abrasion resistance, hydrolysis resistance and rebound resilience, and are used in various applications including elastic fibers. Further improvement in stretchability is achieved.

Various methods for improving the polyol to be used have been proposed as a method for improving the elastic recovery rate of a polyurethane resin using polyoxytetramethylene glycol as a polyol component. For example, a method using a polycarbonate diol obtained by copolymerizing two kinds of diols and diethyl carbonate has been proposed (see, for example, Patent Document 1).
However, in the above method, although the elastic recovery rate is improved as compared with the use of a polycarbonate diol obtained by copolymerizing one kind of diol and diethyl carbonate, the basic skeleton has a carbonate bond with extremely high cohesive force. It does not extend to those using polytetramethylene glycol as the basic skeleton, and its improvement effect is not sufficient.

JP-A-6-49166

  An object of the present invention is to provide a polyurethane resin excellent in elastic properties such as elastic recovery rate, tensile strength and elongation.

  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 is a polyurethane resin obtained by reaction of an active hydrogen component (A) and an organic polyisocyanate component (B), wherein the active hydrogen component (A) is represented by an oxytetramethylene group and the general formula (1). A polyether polyol (a1) having a branched ether group (x) as a structural unit and a polyoxytetramethylene glycol (a2), and the branched ether group in the polyether polyol (a1) ( The polyurethane resin is characterized in that the weight ratio of x) is 40% by weight or more.

[Wherein, R ¹ represents an alkyl group having 1 to 5 carbon atoms, R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, p and r each independently represents an integer of 0 to 6; q represents the integer of 1-6. ]

  The polyurethane resin of the present invention is excellent in elastic properties such as elastic recovery, tensile strength and elongation.

The polyurethane resin of the present invention is obtained by a reaction between an active hydrogen component (A) and an organic polyisocyanate component (B), and the active hydrogen component (A) is an oxytetramethylene group (—OCH ₂ CH ₂ CH ₂ CH ₂ And a polyether polyol (a1) having a branched ether group (x) represented by the general formula (1) as a structural unit, and a polyoxytetramethylene glycol (a2). .

R ¹ in the general formula (1) represents an alkyl group having 1 to 5 carbon atoms, R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, p and r each independently represents an integer of 0 to 6; Q represents an integer of 1-6.

  Examples of the alkyl group having 1 to 5 carbon atoms include methyl group, ethyl group, n- or iso-propyl group, n-, sec-, iso- or tert-butyl group, n- or iso-pentyl group and cyclopentyl group, Etc.

The polyether polyol (a1) in the present invention is a Lewis acid having a rare earth metal such as scandium (III) triflate [Sc (OTf) ₃ ] or scandium (III) trifurylimide [Sc (NTf ₂ ) ₃ ] as an active center. It can be produced by copolymerizing tetrahydrofuran (hereinafter abbreviated as THF) and a branched diol represented by the general formula (2) in the presence of a catalyst. Polyether polyol (a1) may be used individually by 1 type, or may use 2 or more types together.

R ¹ , R ² , p, q and r in the general formula (2) are the same as those in the general formula (1).

  The proportion of the weight of the branched ether group (x) represented by the general formula (1) in the polyether polyol (a1) is usually 40% by weight or more based on the weight of (a1) from the viewpoint of the elastic recovery rate, Preferably it is 50 weight% or more.

  The number average molecular weight (hereinafter abbreviated as Mn) of the polyether polyol (a1) and the polyoxytetramethylene glycol (a2) used in combination is preferably 500 from the viewpoint of the tensile strength, elongation and elastic recovery rate of the polyurethane resin. ˜5000, more preferably 800˜3000. Mn in the present invention is measured by gel permeation chromatography (hereinafter abbreviated as GPC) using THF as a solvent and polyethylene glycol as a standard substance.

  The active hydrogen component (A) in the present invention may further contain a polyol (a3) having a Mn of 500 to 5000, a chain extender (a4), and a reaction terminator (a5).

  As the polyol (a3) having a Mn of 500 to 5000, a polyether polyol, a polyester polyol and other polyols obtained by adding a C2-4 alkylene oxide (hereinafter abbreviated as AO) to a C2-20 polyhydric alcohol. A polyol etc. are mentioned. A polyol (a3) may be used individually by 1 type, or may use 2 or more types together.

  As a C2-C20 polyhydric alcohol used for polyether polyol, it is C2-C20 bihydric alcohol [Aliphatic diol (Ethylene glycol, propylene glycol, 1, 3- or 1, 4- butane diol, 1,6-hexanediol, neopentyl glycol and 1,10-decanediol, etc.), alicyclic diols (cyclohexanediol, cyclohexanedimethanol, etc.) and araliphatic diols [1,4-bis (hydroxyethyl) benzene Etc.], trihydric alcohols having 3 to 20 carbon atoms [aliphatic triols (such as glycerin and trimethylolpropane)] and 4- to 8-hydric alcohols having 5 to 20 carbon atoms [aliphatic polyols (pentaerythritol, sorbitol, Mannitol, sorbitan, diglycerin and dipen Erythritol, etc.) and saccharides (sucrose, glucose, mannose, fructose, methyl glucoside and derivatives thereof)], and the like.

  As AO added to a polyhydric alcohol having 2 to 20 carbon atoms, AO having 2 to 4 carbon atoms, for example, ethylene oxide (hereinafter abbreviated as EO), 1,2-propylene oxide (hereinafter abbreviated as PO), Examples include 1,3-propyloxide, 1,2-, 1,3- or 2,3-butylene oxide and THF. Of these, EO, PO and THF are preferred from the viewpoint of tensile strength. AO may be used alone or in combination of two or more. As an addition method when two or more of AO are used in combination, block addition or random addition may be used. It may be used in combination.

  As the polyester polyol, the polyhydric alcohol having 2 to 20 carbon atoms and / or the polyether polyol, the divalent to tetravalent aromatic polycarboxylic acid and / or the aliphatic polycarboxylic acid, and their anhydrides or lower alkyls ( Condensation reaction products with ester-forming derivatives such as esters having an alkyl group having 1 to 4 carbon atoms; these AO adducts; polylactone polyols [for example, lactones having a polyhydric alcohol having 2 to 20 carbon atoms as an initiator obtained by ring-opening polymerization of ε-caprolactone and the like]; and polycarbonate polyol (for example, a reaction product of the polyhydric alcohol having 2 to 20 carbon atoms and alkylene carbonate).

  Examples of the divalent to tetravalent aromatic polycarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8- Naphthalenedicarboxylic acid, anthracene dicarboxylic acid, 4,4′-benzophenone dicarboxylic acid, 3,3′-biphenyl dicarboxylic acid, 4,4′-biphenyl dicarboxylic acid, 3,3′-biphenyl ether dicarboxylic acid, 4,4′- Examples thereof include aromatic dicarboxylic acids having 8 to 30 carbon atoms such as biphenyl ether dicarboxylic acid and 4,4′-binaphthyl dicarboxylic acid, and the above trivalent or tetravalent aromatic polycarboxylic acids.

  Examples of the divalent to tetravalent aliphatic polycarboxylic acid include oxalic acid, succinic acid, malonic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, itaconic acid, tricarbaryl. Examples thereof include aliphatic polycarboxylic acids having 2 to 30 carbon atoms such as acid and hexanetricarboxylic acid.

  Examples of other polyols include monocyclic polyhydric phenols (pyrogallol, hydroquinone, phloroglucin, etc.) or bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.) added with AO, polyols, silicone polyols, polymer polyols, polydienes Examples include polyols (such as polybutadiene polyols), hydrogenated products of polydiene polyols, acrylic polyols, natural oil-based polyols (such as castor oil), and modified products of natural oil-based polyols.

  As the chain extender (a4), water, the above polyhydric alcohol having 2 to 20 carbon atoms, diamine having 2 to 10 carbon atoms (for example, ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, toluenediamine and piperazine), Polyalkylene polyamines (for example, diethylenetriamine and triethylenetetramine), hydrazine or derivatives thereof (for example, dibasic acid dihydrazides such as adipic acid dihydrazide) and amino alcohols having 2 to 10 carbon atoms (for example, monoethanolamine, diethanolamine, 2-amino) -2-methylpropanol and triethanolamine). A chain extender (a4) may be used individually by 1 type, or may use 2 or more types together.

  As the reaction terminator (a5), monoalcohols having 1 to 8 carbon atoms (methanol, ethanol, isopropanol, cellosolves and carbitols) and monoamines having 1 to 10 carbon atoms (monomethylamine, monoethylamine, mono Mono- or dialkylamines such as butylamine, dibutylamine and monooctylamine; mono- or dialkanolamines such as monoethanolamine, diethanolamine and diisopropanolamine). As the reaction terminator (a5), one type may be used alone, or two or more types may be used in combination.

  The ratio of the total weight of the polyether polyol (a1) and the polyoxytetramethylene glycol (a2) in the active hydrogen component (A) is based on the weight of (A) from the viewpoint of the tensile strength, elongation and elastic recovery rate of the polyurethane resin. Is preferably at least 70% by weight, more preferably 80 to 99.9% by weight.

  The weight ratio of the polyether polyol (a1) to the total weight of the polyether polyol (a1) and the polyoxytetramethylene glycol (a2) is preferably 1 from the viewpoint of the tensile strength, elongation and elastic recovery rate of the polyurethane resin. -50% by weight, more preferably 3-30% by weight.

  As the organic polyisocyanate component (B), all organic polyisocyanates generally used in the production of polyurethane resins can be used. For example, aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, araliphatic polyisocyanates and These modified products (urethane group, carbodiimide group, allophanate group, urea group, burette group, isocyanurate group, oxazolidone group-containing modified product, etc.) can be mentioned. An organic polyisocyanate component (B) may be used individually by 1 type, or may use 2 or more types together.

  Aromatic polyisocyanates include aromatic diisocyanates having 6 to 16 carbon atoms (excluding carbons in NCO groups; the following polyisocyanates are also the same), aromatic triisocyanates having 6 to 20 carbon atoms, and crude products of these isocyanates. Thing etc. are mentioned. Specific examples include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (hereinafter abbreviated as TDI), crude TDI, 2,4′- or 4,4 ′. -Diphenylmethane diisocyanate (hereinafter abbreviated as MDI), polymethylene polyphenylene polyisocyanate (hereinafter abbreviated as crude MDI), naphthylene-1,5-diisocyanate, triphenylmethane-4,4 ', 4' '-triisocyanate and the like Can be mentioned.

  Examples of the aliphatic polyisocyanate include aliphatic diisocyanates having 6 to 10 carbon atoms (such as 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate).

  Examples of the alicyclic polyisocyanate include alicyclic diisocyanates having 6 to 16 carbon atoms (such as isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and norbornane diisocyanate).

Examples of the araliphatic isocyanate include araliphatic diisocyanates having 8 to 12 carbon atoms (such as xylylene diisocyanate and α, α, α ′, α′-tetramethylxylylene diisocyanate).
Specific examples of the modified polyisocyanate include carbodiimide-modified MDI.

  Among these, aromatic polyisocyanates are preferable from the viewpoint of the tensile strength of the polyurethane resin, and more preferable are TDI, crude TDI, MDI, crude MDI, and modified products of these isocyanates. The total content of MDI, crude MDI and their modified products is 10% by weight or more (especially 15 to 80% by weight), and the content of TDI, crude TDI and their modified products (especially TDI) is 90% by weight. The following (especially 20 to 85% by weight). The isocyanate group content (NCO%) of the organic polyisocyanate component (B) as a whole is preferably 25 to 45% by weight.

  The production method of the polyurethane resin of the present invention is not particularly limited, but a stationary premixer comprises (a1), (a2) and, if necessary, a urethane prepolymer obtained by reacting (a3) and (B) and preferably an organic solvent. In a method of batch mixing and reacting the urethane prepolymer, the chain extender (a4) and, if necessary, the reaction terminator (a5) with a flash mixer in a batch mixer (A) (B) and, if necessary, a method in which an organic solvent is charged all at once and heated to react, and if necessary, a reaction terminator (a5) is added.

  Examples of the organic solvent include solvents that do not contain an active hydrogen group. Specific examples include amide solvents (N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, etc.), sulfoxide solvents (dimethyl sulfoxide, etc.), ketone solvents (methyl ethyl ketone, methyl isobutyl ketone, etc.) Ether solvents (dioxane, THF, etc.), ester solvents (methyl acetate, ethyl acetate, butyl acetate, etc.), aromatic solvents (toluene, xylene, etc.) and the like. An organic solvent may be used individually by 1 type, or may use 2 or more types together.

  In the production of the polyurethane resin, it is possible to mix one or more amine-based catalysts and organometallic catalysts. Examples thereof include those disclosed in Japanese Patent Publication No. 11-200367.

  The polyurethane resin of the present invention can be used by adding pigments, stabilizers and other additives.

  As a pigment, a well-known organic pigment and / or an inorganic pigment can be used, and 0-5 weight% normally with respect to a polyurethane resin, Preferably 0.1-3 weight% is mix | blended. Examples of organic pigments include insoluble azo pigments, soluble azo pigments, copper phthalocyanine pigments, and quinacridone pigments. Examples of inorganic pigments include chromates, ferrocyan compounds, metal oxides, selenium sulfide compounds, metal salts. (Sulfates, silicates, carbonates, phosphates, etc.), metal powders, carbon black and the like.

The stabilizer is not particularly limited, and a known antioxidant and / or ultraviolet absorber can be used, and is usually 0 to 5% by weight, preferably 0.1 to 3% by weight based on the polyurethane resin. The
Antioxidants include phenolic [2,6-di-t-butyl-p-cresol and butylated hydroxyanisole, etc.]; bisphenol [2,2′-methylenebis (4-methyl-6-t-butylphenol) Etc.]; phosphorus-based [triphenyl phosphite and diphenylisodecyl phosphite etc.] and the like.

Examples of the ultraviolet absorber include benzophenone [2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone and the like]; benzotriazole [2- (2′-hydroxy-5′-methylphenyl) benzotriazole and the like]; Salicylic acid type [phenyl salicylate and the like]; hindered amine type [bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and the like] and the like.
Other additives include anti-fusing agents and flame retardants.

  The pigment, stabilizer and other additives can be added at any stage during the production of the polyurethane resin, and may be added after the production.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. In the following description, “parts” indicates parts by weight.

<Production Example 1> Synthesis of polyether polyol (a1-1) obtained by copolymerization of THF and neopentyl glycol (hereinafter abbreviated as NPG):
230 parts of THF and 33 parts of NPG were charged into a reaction vessel equipped with a stirrer, a distiller, a condenser tube and an adsorption tower, and then 0.55 parts of scandium (III) triflate [Sc (OTf) ₃ ] was added. Stirring is continued for 15 hours with the heating bath temperature set at 75 ° C., and the generated water is fed from the bottom of the tower to a glass adsorption tower (diameter 22 mm, height 500 mm) filled with 50 parts of type 3A molecular sieve together with THF. And extracted from the top of the column and returned to the reactor. The adsorption tower used was pre-filled with THF. The distillate from the reaction system in the reaction for 15 hours was about 600 parts, and water was adsorbed and removed, and the whole amount was returned to the reactor. After completion of the reaction, the reaction solution was allowed to stand at room temperature and separated into two layers. The upper layer liquid was extracted by decantation, and a strong acidic cation exchange resin (“Amberlyst” manufactured by Organo Corporation) was added to remove the contained catalyst, followed by filtration. Subsequently, THF in the filtrate was removed by evaporation to obtain the desired polyether polyol (a1-1) as a transparent and viscous liquid. Branched ether in which R ¹ and R ² are methyl groups and p, q and r are 1 in the general formula (1) derived from NPG in (a1-1) obtained by ¹ H-NMR (400 MHz) measurement The weight ratio of the group was 50.4% by weight, and Mn of (a1-1) by GPC measurement was 2005.

<Comparative Production Example 1> Synthesis of polyether polyol (a6) obtained by copolymerization of THF and neopentyl glycol:
Into a reaction vessel equipped with a stirrer, a distiller, a cooling pipe and an adsorption tower, 230 parts of THF and 33 parts of NPG were charged, and then 12 tungsto (VI) phosphoric acid n hydrate (H ₃ PW ₁₂ O ₄₀ / nH ₂ O) 150 parts of [Wako Pure Chemical Industries, Ltd.] were added. Stirring is continued for 15 hours with the heating bath temperature set at 75 ° C., and the generated water is fed from the bottom of the tower to a glass adsorption tower (diameter 22 mm, height 500 mm) filled with 50 parts of type 3A molecular sieve together with THF. And extracted from the top of the column and returned to the reactor. The adsorption tower used was pre-filled with THF. The distillate from the reaction system in the reaction for 15 hours was about 600 parts, and water was adsorbed and removed, and the whole amount was returned to the reactor. After completion of the reaction, the reaction solution was allowed to stand at room temperature and separated into two layers. The upper layer liquid was extracted by decantation, and calcium hydroxide was added to precipitate a trace amount of the catalyst, followed by filtration. Subsequently, THF in the filtrate was removed by evaporation to obtain the desired polyether polyol (a6-1) as a transparent and viscous liquid. Branched ether in which R ¹ and R ² are methyl groups and p, q and r are 1 in the general formula (1) derived from NPG in (a6-1) determined by ¹ H-NMR (400 MHz) measurement The weight ratio of the group was 22.2% by weight, and Mn of (a6-1) was 2008 by GPC measurement.

<Example 1 and Comparative Examples 1-2>
In a reaction vessel equipped with a stirrer and a thermometer, according to the formulation shown in Table 1, the polyether polyol (a1), polyoxytetramethylene glycol (a2), and Mn of 500 to 5000 in the active hydrogen component (A) A polyol (a3), a chain extender (a4), a polyether polyol (a6) having a low content of branched ether groups, an organic polyisocyanate component (B), and an organic solvent are charged, and the reaction is carried out at 70 ° C. in a dry nitrogen atmosphere. It was made to react for 10 hours, the reaction terminator (a5) was prepared after that, and the terminal termination reaction was performed for 1 hour, and the solution of the polyurethane resin of Example 1 and Comparative Examples 1-2 was obtained.
In addition, the composition of PTMG2000 and PP-2000 in Table 1 is as follows.
PTMG2000: polytetramethylene ether glycol, Mn = 1975 (“PTMG2000” manufactured by Mitsubishi Chemical Corporation)
PP-2000: Polyoxypropylene diol having Mn of 1941 obtained by adding PO to propylene glycol (“SANNICS PP-2000” manufactured by Sanyo Chemical Industries, Ltd.)

  Table 1 shows the results of measuring the values of the tensile strength, elongation and elastic recovery of the polyurethane resins in the polyurethane resin solutions obtained in Example 1 and Comparative Examples 1 and 2 by the following methods.

[1] Film production method A polyurethane resin solution is applied to a release-treated glass plate to a thickness of 0.7 mm, dried in a circulating dryer at 70 ° C. for 3 hours, and then peeled off from the glass plate. A film having a thickness of about 0.2 mm was produced.

[2] Measuring method of tensile strength and elongation of film After leaving the film obtained above in a room adjusted to a temperature of 25 ° C. and a humidity of 65% RH for one day, the tensile strength and elongation were measured according to JIS K 6251. did.

[3] Measuring method of elastic recovery rate Using an Instron type tensile tester (manufactured by Shimadzu Corporation) in an atmosphere of 25 ° C., a test piece produced in the same manner as the measuring method of tensile strength and elongation of the film was used. The process of stretching 300% at a pulling speed of 50 cm / min and returning to the state before stretching at the same speed as the pulling speed was repeated four times, and then stretching 300% at a pulling speed of 50 cm / min and holding for 30 seconds. After the operation to return to the state before stretching at the same speed as the tensile speed, measure the distance (L ₅ ) between the marked lines and use this value and the distance (L ₀ ) between the marked lines before the test. The elastic recovery rate was calculated from the equation.
Elastic recovery rate (%) = {1− (L ₅ −L ₀ ) / L ₀ } × 100

  The polyurethane resin of the present invention is suitable as a raw material for producing elastic fibers, thermoplastic elastomers, paints, synthetic leathers and the like because it is excellent in elastic properties such as elastic recovery, tensile strength and elongation.

Claims (3)

A polyurethane resin obtained by reacting an active hydrogen component (A) with an organic polyisocyanate component (B), wherein the active hydrogen component (A) is a branched form represented by the oxytetramethylene group and the general formula (1) Weight ratio of branched ether group (x) in polyether polyol (a1), comprising polyether polyol (a1) having ether group (x) as a structural unit and polyoxytetramethylene glycol (a2) Is a polyurethane resin, characterized in that is 40% by weight or more.

[R ¹ in General Formula (1) represents an alkyl group having 1 to 5 carbon atoms, R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and p and r each independently represent 0 to 6 carbon atoms. Represents an integer, q represents an integer of 1 to 6; ]   The proportion of the total weight of the polyether polyol (a1) and the polyoxytetramethylene glycol (a2) in the active hydrogen component (A) is at least 70% by weight based on the weight of (A), and the polyether polyol (a1) and The polyurethane resin according to claim 1, wherein the weight ratio of the polyether polyol (a1) to the total weight of the polyoxytetramethylene glycol (a2) is 1 to 50% by weight.   The polyurethane resin according to claim 1 or 2, wherein the polyether polyol (a1) and the polyoxytetramethylene glycol (a2) have a number average molecular weight of 500 to 5,000.