JPS6329686B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing thermoplastic polyurethane resin. More specifically, the present invention relates to a method for producing a thermoplastic polyurethane resin that is soluble in organic solvents, has high mechanical properties, and has groups having active hydrogen pendantly and/or at the end of the molecule. Thermoplastic polyurethane resin (hereinafter simply referred to as TPU) is used in some fields by being dissolved in a solvent. In such fields, it is often dissolved in a solvent due to the necessity of coating operations.
Generally, the solvent is removed after application. In this case, after removing the solvent, the solvent resistance,
Water resistance, heat resistance, etc. may be required, and for this purpose, it is simple and effective to introduce active hydrogen into the TPU molecule and crosslink and harden it using polyisocyanate etc. at the time of application. well known. On the other hand, TPU is used in some fields where it is mixed with inorganic materials, but in this field, the dispersibility of inorganic materials is sometimes required, and for this purpose TPU has sulfonic, carboxyl, and phosphoric acid groups. It is also effective to introduce a group such as a hydroxyl group or an amino group into the molecule, but this may cause gelation when forming a paint, so it is common to introduce a group having active hydrogen such as a hydroxyl group or an amino group. Furthermore, even in these applications, it is desirable that TPU alone has sufficient mechanical properties. Therefore, the present inventors investigated a new method for manufacturing TPU that is soluble in organic solvents, has high mechanical properties, and has a group containing active hydrogen in its molecule.
We have arrived at the present invention. That is, the present invention provides a method for producing a thermoplastic polyurethane elastomer by reacting a high molecular diol (A) with an average molecular weight of 500 to 5000, a low molecular diol (B) with an average molecular weight of 500 or less, and an organic diisocyanate (C). 1) A, B, and C are reacted in an organic solvent at a ratio of the total number of active hydrogens of A and B to the number of isocyanate groups of C in a ratio of 1:1.02 to 1:1.1 to form isocyanate groups at the terminals. prepolymer with
(D), (2) followed by a crosslinking agent (E) having three or more active hydrogen atoms,
The ratio of the number of isocyanate groups in C to the total number of active hydrogens in A, B and E is 1:0.85 to 1:
A method for producing a thermoplastic polyurethane resin, characterized in that the molecular structure of the thermoplastic polyurethane elastomer obtained by adding at a ratio of 0.98 and chain-extending D with E has at least two OH groups at the molecular terminal. It is. The solvents used in the present invention include one or more of amide, sulfoxide, cyclic ether, cyclic ketone, and acyclic ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, as well as the above solvents and ethyl acetate. , ester-based solvents such as butyl acetate, aromatic hydrocarbon-based solvents such as benzene, toluene, and xylene, and mixed solvents with chlorinated solvents such as methylene chloride and perchlorethylene. The polymer diol (A) used in the present invention has an average molecular weight of
500 to 5000, and include known polyether diols, polyester diols, polycarbonate diols, etc. Examples of polyether diols include water, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-
Alternatively, one or more alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide, etc. are added to 1,4-butylene glycol, 1,6-hexamethylene glycol, etc. (hereinafter simply referred to as alkylene oxide). ) is obtained by adding Polyester diols include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,3- or 1,4-butylene glycol, neopentyl glycol, 1,
One or more of 6-hexamethylene glycol, decamethylene glycol, etc., and malonic acid, maleic acid, succinic acid, adipic acid, glutaric acid,
pimelic acid, sebacic acid, oxalic acid, phthalic acid,
Polyester diols from one or more of isophthalic acid, terephthalic acid, hexahydrophthalic acid, etc. or diols obtained by ring-opening polymerization of cyclic esters such as propiolactone, butyrolactone, caprolactone, etc., and further from the above glycols and cyclic esters. Alternatively, it is a polyester diol selected from the above three types of glycols, dibasic acids, and cyclic esters. Polycarbonate diol has the general formula H[-O-
R-OCO]- _o In the compound represented by ROH (n≧1), R is a residue of glycol or divalent phenol, and glycol or divalent phenol is, for example, trimethylene glycol, diethylene glycol, 1,3- or 1,4-butylene glycol, 1,6-hexamethylene glycol, decamethylene glycol, p-xylylene glycol,
Bisphenol A [2,2-bis(4'-hydroxyphenyl)propane], bisphenol F (4,
4′-dihydroxydiphenylmethane), etc. As the polymer diol of the present invention, 1,2-polybutadiene glycol, 1,4-polybutadiene glycol, polychloroprene diol, putadiene-acrylonitrile copolymer diol, etc. can also be used. These various polymeric diols may be used alone or in combination of two or more. The low molecular weight diol (B) having an average molecular weight of 500 or less used in the present invention includes known aliphatic diols, aromatic diols, N-alkyl or N-aryldialkanolamines, and the like. Aliphatic diols include, for example, ethylene glycol, propylene glycol, 1,3- or 1,4-butylene glycol,
1,5-pentanediol, 1,6-hexamethylene glycol, neopentyl glycol, 2-
Ethyl-1,3-hexanediol, 2,2,4
-trimethyl-1,3-pentanediol, 2,
2,4- or 2,4,4-trimethyl-1,6-
hexanediol, decamethylene glycol,
1,4-cyclohexanediol and the like. Examples of aromatic diols include hydroquinone, bisphenol A, bisphenol F, and p-xylylene glycol. Examples of N-alkyl or N-aryl dialkanolamines include methyldiethanolamine, methyldiisopropanolamine, ethyldiethanolamine, phenyldiethanolamine, m-tolyldiethanolamine, and the like. The above B is the aliphatic diol,
Those obtained by adding alkylene oxide to aromatic diols, N-alkyl or N-aryl dialkanolamines are also used. These various low molecular weight diols (B) having an average molecular weight of 500 or less may be used alone or in combination of two or more. The crosslinking agent E having three or more active hydrogens used in the present invention includes known polyols, alkanolamines, polyamines, and the like. Examples of polyols include trimethylolpropane, glycerin, 3-methylpentane-1,3,5-triol, pentaerythritol, sorbitol, sucrose, polyglycerin, tris(β-hydroxyethyl)isocyanurate, and alkylene oxide adducts thereof. Or ε-caprolactone adduct, polyester polyol, etc. Examples of alkanolamines include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, and triisopropanolamine. Examples of polyamines include ethylenediamine, diethylenetriamine, tolylenediamine,
These include diphenylmethanediamine, isophoronediamine, 4,4'-methylenebis(2-chloroaniline), and the like. These various crosslinking agents having three or more active hydrogens may be used alone or in combination of two or more. The organic diisocyanate (C) used in the present invention is, for example, tolylene diisocyanate (various isomer ratios), diphenylmethane-4,4'-diisocyanate (hereinafter also referred to as MDI), naphthylene-1,
5-diisocyanate, 3,3'-dimethyl-4,
4'-Biphenylene diisocyanate, xylylene diisocyanate, dicyclohexylmethane-
These include 4,4'-diisocyanate (hydrogenated MDI), isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and the like. These various organic diisocyanates may be used alone or in combination of two or more. High molecular diol (A) and low molecular diol of the present invention
(B), crosslinking agent (E), and organic diisocyanate (C) are (1) NCO-terminated prepolymer from A, B, and C.
When producing (D), the number of isocyanate groups in C is 1 for the total number of active hydrogens in A and B.
1.02 to 1.1; (2) When manufacturing TPU from D and E, A,
The number of isocyanate groups in C is 0.85 to 0.98 relative to the total number of active hydrogens in B and E, which is 1. Used in quantitative relationships such as Under the conditions (1), in order to obtain TPU with good solubility in a solvent, it is preferable to carry out chain extension with an excess of isocyanate groups to obtain an NCO-terminated prepolymer (F). However, if the number exceeds 1.1 and there are many isocyanate groups, chain extension will be insufficient, the molecular weight of the polymer will not increase, and the physical properties will deteriorate. On the other hand, when the number of isocyanate groups is less than 1.02, the number of active hydrogens that can be introduced into the molecule decreases, which is not preferable. Under condition (2), if the number of isocyanate groups is less than 0.85, the amount of unreacted E will be excessive, causing blooming or bleeding of the cured product. On the other hand, if the number of isocyanate groups exceeds 0.98, there is a risk of gelation of the reaction solution, which is not preferable. Note that under the conditions (2), if the number of isocyanate groups after the reaction is less than 0.85, or if necessary to adjust the viscosity of the product, an organic polyisocyanate may be added. However, in this case, the total number of isocyanate groups of the added organic polyisocyanate and C is within the range of 0.85 to 0.98, and the added organic polyisocyanate may be the same type as C or different. In the present invention, a conventionally known urethanization catalyst is used as necessary at any stage of the reaction. Further, in the present invention, various additives such as antioxidants, ultraviolet absorbers, and carbodiimides are used as necessary. To outline the production of TPU of the present invention, polymer diol (A), organic diisocyanate (C), and if necessary urethanization catalyst are mixed in a solvent at 20 to 80% by weight (hereinafter %
represents weight %. ) 50-90℃, with solids content of
Allow to react for 1 to 3 hours. Furthermore, a low molecular weight diol (B) is reacted at 50 to 90°C by charging all at once or in portions. As the viscosity of the reaction solution increases, a solvent and a catalyst are added as necessary to cause a reaction, thereby obtaining an NCO-terminated prepolymer solution (D). (D) is reacted with the crosslinking agent (E) and, if necessary, a solvent, at 5 to 90°C by charging them all at once. After reacting for 1 to 3 hours, organic diisocyanate is reacted at 5 to 90° C., either all at once or in portions, if necessary. (The above conditions indicate normal conditions and are not necessarily limited to these.) The obtained TPU solution preferably has a solids content of 10 to 40%, and is approximately 30% solution. The viscosity at 25° C. is preferably 1000 centipoise or more. If the viscosity is lower than this, good physical properties cannot be obtained. The present invention provides TPU that is soluble in organic solvents, has high mechanical properties, and has at least two or more active hydrogens per molecule end and/or active hydrogens pendant in the molecule. In addition, the polymer diol (A), low molecular diol (B), and organic diisocyanate (C) of the present invention have an amount of A based on the total weight of A, B, and D.
By changing the weight ratio of
You can get TPU. Furthermore, the TPU of the present invention
is a reaction product of trimethylolpropane and 3 mol of tolylene diisocyanate, a reaction product of trimethylolpropane and 3 mol of hexamethylene diisocyanate, a polyisocyanate such as hexamethylene diisocyanate modified by introducing a Biuret group, and a preform containing an NCO group. By combining with polymers, blocked polyisocyanates, etc., cured products can be obtained. In the present invention, TPU can be used in resins, films, various coatings, impregnating agents, adhesives, paints, binders,
Used in binders for magnetic paints, ink vehicles, etc. Next, the present invention will be specifically explained with reference to Examples. Example 1 After purging the reactor with a stirrer and a reflux condenser with nitrogen gas, 500 parts of methyl ethyl ketone (hereinafter simply referred to as MEK) was charged, and polyester diol (produced from ethylene glycol, 1,4-butylene glycol, and adipic acid) was charged. Polyester diol, average molecular weight 1600.Hereafter simply referred to as PEBA)
100 parts of MDI (mentioned above), 291.3 parts of MDI (mentioned above), and 0.05 part of dibutyltin dilaurate (hereinafter simply referred to as DBTDL) were added, and the mixture was reacted at 80°C for 2 hours. Add neopentyl glycol (hereinafter simply referred to as NPG) to the above solution.
107.3 parts were added and reacted at 80°C for 1 hour to obtain an NCO-terminated prepolymer solution. To this prepolymer solution, 700 parts of NEK and 16.7 parts of trimethylolpropane (hereinafter simply referred to as TMP) were added and reacted at 80°C for 1 hour to obtain a prepolymer solution containing hydroxyl groups (that is, active hydrogen). Add to this hydroxyl group-containing prepolymer solution at 80℃.
10.9 parts of MDI (mentioned above) was added and reacted at 80°C for 1 hour. The obtained TPU solution has a solid content of 32.0% and a viscosity of 1900 centipoise (25°C), and the resin obtained from this solution has a Ys (stress at yield) of 650 Kg/cm ² ,
The elongation at yield was 4.3%, and the Young's modulus was 23,800 Kg/cm ² . Ys, elongation at yield, and Young's modulus were measured on a rectangular sample with a width of 5 mm at a distance between gauge lines of 50 mm and a tensile speed of 5 mm/min. Examples 2-3 The resins of Examples 2-3 were produced in the same manner as in Example 1 except that MDI was added all at once. The composition and properties of the resin are shown in Table 1.

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Claims (1)

[Claims] 1. A polymeric diol (A) having an average molecular weight of 500 to 5000,
In a method for producing a thermoplastic polyurethane elastomer by reacting a low molecular diol (B) with an average molecular weight of 500 or less and an organic diisocyanate (C), (1) the total number of active hydrogens in A and B and the number of isocyanate groups in C; A prepolymer having isocyanate groups at the terminals by reacting A, B and C in an organic solvent in a number ratio of 1:1.02 to 1:1.1
(D), (2) followed by a crosslinking agent (E) having three or more active hydrogen atoms,
The ratio of the number of isocyanate groups in C to the total number of active hydrogens in A, B and E is 1:0.85 to 1:
A method for producing a thermoplastic polyurethane resin, characterized in that the molecular structure of the thermoplastic polyurethane elastomer obtained by adding D at a ratio of 0.98 and chain-extending D with E has at least two OH groups at the molecular terminals.