JPH0364529B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to epoxy-modified polyurethane resins having a large number of OH groups. Blends of simple epoxy resins and urethane resins have been known in the past, but they have the drawback of poor dispersibility of pigments and fillers and poor toughness of the coating film when cured. In other words, when an epoxy group is cured, an OH group remains, and when an OH group is crosslinked with an isocyanate compound, an epoxy group remains, so it is necessary to use separate curing methods. is unbalanced in its strength, flexibility, and hardness. Moreover, before curing, OH
Since the number of groups is small, the dispersibility of pigments and fillers is poor, so variations in properties are more likely to occur. An object of the present invention is to provide an epoxy-modified polyurethane resin that provides a cured resin with an excellent balance of strength, flexibility, hardness, etc. Another object of the present invention is to provide an epoxy-modified polyurethane resin that has a large number of OH groups and has excellent dispersibility of pigments and fillers. In the present invention, a part or all of the epoxy groups of an epoxy-modified polyurethane obtained by reacting an epoxy compound, a polyol, and an isocyanate compound having two or more OH groups on average in the molecule are opened with amines and/or carboxylic acids. Formula obtained by ringing to generate OH group (In the formula, X is

[Formula] or -N-) in the molecule, a number average molecular weight of 4,000 to 20,000, a hydroxyl group concentration of 0.1 to 1.0 meq/g, a viscosity of 200 to 2,000 mPa・s (25°C) It relates to an epoxy-modified polyurethane resin. In the present invention, the number average molecular weight is a value measured by gel permeation chromatography manufactured by Waters Inc. and converted from standard polystyrene, and the viscosity is a value of a 40% solids solution in a mixed solution of cyclohexane/methyl ethyl ketone = 4/5. twenty five
Shows viscosity in °C. In addition, the hydroxyl group concentration
1.0meq/g polymer means that per 1g of polymer,
This means that 1.0 milliequivalents of OH are present, so in a polymer with a molecular weight of 4000, there are 4000 x 1.0 x 10 ^-3
=4.0 equivalents, meaning that 4 OH groups are present. The material of the present invention has the advantages of both the toughness of polyurethane and the hardness and adhesive strength of epoxy resin, and can be cured with an isocyanate compound. Moreover, because it has many OH groups in its molecules, it has excellent dispersibility of pigments, fillers, and other magnetic powders. The present invention can be used in various fields, such as paint vehicles, magnetic tape binders, coating agents, adhesives, and the like. It is particularly effective in fields where affinity with fillers and the like that require abrasion resistance and dispersibility are required, and is especially suitable as a binder for magnetic tapes. In the present invention, first, an epoxy compound, a polyol, and an isocyanate compound having an average of two or more OH groups in the molecule are reacted to obtain an epoxy-modified polyurethane. In this case it is also optional to use chain extenders. As the epoxy compound, a bisphenol type epoxy resin is preferably used, and an epoxy resin represented by the following formula is particularly suitable. (R ¹ and R ² are each hydrogen or methyl group, X is hydrogen, methyl group, chlorine, bromine, or iodine, and n is a number of 1 or more) (Y is S or SO ₂ , m is a number of 1 or more) Specific examples of product names include Epicote 828,
Examples include 838, 1001, 1002, 1003, 1004, 1007, and 1009 (all manufactured by Ciel Chemical). In addition, other epoxy compounds include epoxy resins containing bromine, such as Epicote 1045-B-80 and 1046-B-
80, 1050 (manufactured by Yuka Ciel Epoxy Co., Ltd.), Sumiepoxy ESB-340, 400, 500, 700, 715 (manufactured by Sumitomo Chemical Industries), and the like. In the present invention, the polyol has a molecular weight of
500-5000 various polyester polyols, polyether polyols, and other polyols can be used. Specific examples of polyester polyols include adipate polyols such as polyethylene adipate polyol, polybutylene adipate polyol, and polyethylene propylene adipate polyol, and terephthalic acid polyols (e.g., Toyobo Co., Ltd., product names Byron RUX, Byron RV-).
200L), polycaprolactone polyol (e.g., Daicel Chemical, trade name Plaxel 212, Plaxel
220), etc., and specific examples of polyether polyols include polyoxyethylene glycol, polyoxypropylene polyol, polyoxytetramethylene polyol, and the like. In addition, other polyols include polycarbonate polyol (e.g., West Germany, Bayer AG, trade name: Desmofene 2020E), polybutadiene polyol (e.g., Nippon Soda, trade name: G-1000, G-
2000, G-3000, Idemitsu Petrochemical, trade name PoLY
bd R-45 HT), polypentadiene polyol,
Castor oil-based polyols can be mentioned, and 1
A species or two or more species can be used. The isocyanate compound used in the present invention may be any polyisocyanate known in polyurethane chemistry, such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI),
2,4-tolylene diisocyanate (2,4-
TDI), 2,6-tolylene diisocyanate (2,
6-TDI), 4,4'-diphenylmethane diisocyanate (MDI), carbodiimide-modified MDI, polymethylene polyphenyl polyisocyanate (PAPI), orthotoluidine diisocyanate (TODI), naphthylene diisocyanate (NDI),
Examples include xylylene diisocyanate (XDI) and lysine diisocyanate (LDI), and one type or two or more types can be used. As a chain extender, for example, 2 with a molecular weight of 500 or less
~6-functional polyol and 1 with a molecular weight of 500 or less
Diamines having a primary or secondary terminal amino group are mentioned. Suitable chain extenders include (a) ethylene glycol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,4-butanediol,
2,3-butanediol, 1,3-propylene glycol, 1,6-hexanediol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, metaxylylene Polyols such as glycol and paraxylylene glycol (b) Hydrazine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 1,
Diamines such as 4-cyclohexanediamine (c) Alkanolamines such as ethanolamine, diethanolamine, and triethanolamine (d) Hydroquinone, pyrogallol, 4,4'-isopropylidene diphenol, aniline, and the above polyols and diamines and polyols with a molecular weight of 500 or less obtained by adding propylene oxide and/or ethylene oxide to alkanolamines in any order. Epoxy-modified polyurethane is synthesized using the above-mentioned components, and in this case, the reaction is usually carried out at an NCO index of about 0.7 to 1.2, preferably about 0.9 to 1.1. In the present invention, the epoxy groups of the above-mentioned epoxy-modified polyurethane are further reacted with amines and/or carboxylic acids to open the ring and generate OH groups to obtain the desired epoxy-modified polyurethane resin. The amines are preferably compounds containing secondary amino groups, such as dialkylamines such as diethylamine, dipropylamine, and dibutylamine;
Alkanolamines such as N-methylethanolamine, N-butylethanolamine, diethanolamine, and dipropanolamine, and carboxylic acids such as acetic acid, propionic acid, stearic acid, succinic acid, adipic acid, maleic acid, benzoic acid, and phthalic acid. , phenylacetic acid, hydroxyacetic acid (glycolic acid), lactic acid, 2,2-dimethylolpropionic acid, 9,10,11,12,13-tetraoxyoctadecanoic acid, acetic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride Examples include acids. These amines and carboxylic acids can be used alone or in combination. In the above-mentioned ring-opening reaction of the present invention, part or all of the epoxy group can be ring-opened, and the amount of amines and/or carboxylic acids is usually about 1 equivalent or less, preferably about 0.2 to 1 equivalent to the epoxy group. It is better to use double equivalents. The reaction is usually carried out at about 20 to 180°C, preferably about 100 to 150°C. The ring-opened modified polyurethane resin of the present invention has a large number of OH groups in its molecules and has extremely good dispersibility of pigments, magnetic powders, other fillers, and the like. The number of OH groups is usually preferably 3 or more, and generally 6 to 30.
OH groups, particularly preferably 10 to 20 OH groups. In the present invention, a polyfunctional isocyanate compound can be further blended with the epoxy-modified polyurethane resin, and when this composition is cured, excellent film strength and heat deformation resistance can be obtained. As the polyfunctional isocyanate compound in the present invention, a polyisocyanate having two or more functional groups can be used. Preferred specific examples include various isocyanate compounds that can be used in the production of the epoxy-modified polyurethane, trifunctional isocyanate obtained from trimethylolpropane and TDI (trade name: Desmodyur L, Bayer AG, West Germany), Trifunctional isocyanate (product name Desmodyur N-
75, R, H, etc.), polymeric polyisocyanate (PPI), and the like. EXAMPLES The present invention will be described in detail below with reference to Examples, Comparative Examples, and Test Examples. Note that parts and % simply indicate parts by weight and % by weight. Example 1 280 g of Vylon RV-200L (OH value 56.1) polycaprolactone diol (OH value 56.1) in two separable flasks equipped with a thermometer, stirrer, nitrogen gas introduction tube, and condenser.
120g Epicote 1001 36g IPDI 64.0g Cyclohexanone 152g were weighed out and reacted at 110°C for 2 hours in a stream of dry nitrogen. Then 192g of cyclohexanone and 1,6
-Add 7.1g of hexanediol and further heat at 110℃ for 1 hour.
After heating for an hour, 0.13 g of dibutyltin dilaurate was added and reacted for 2 hours. This epoxy-modified polyurethane solution and 8.4 g of diethanolamine were reacted at 130°C for 2 hours, and in the infrared absorption spectrum, 905cm
After absorption of ^-1 has disappeared, cool to 70°C and add 429 g of methyl ethyl ketone (MEK). The resulting solution has a solid content of 40% and a viscosity of 320mPa.

Claims (1)

[Claims] 1. Part or all of the epoxy groups of the epoxy-modified polyurethane obtained by reacting an epoxy compound, a polyol, and an isocyanate compound each having two or more OH groups in the molecule on average are amines and/or Formula obtained by ring opening with carboxylic acids to generate OH group (wherein, X represents [formula] or -N-) in the molecule, a number average molecular weight of 4000 to 20000, a hydroxyl group concentration of 0.1 to 1.0 meq/g, a viscosity of 200 to 2000 mPa・Epoxy-modified polyurethane resin that is s (25℃). 2 The epoxy compound has the formula (R ¹ and R ² are each hydrogen or a methyl group, X is hydrogen, a methyl group, chlorine, bromine, or iodine, and n is a number of 1 or more) according to claim 1. resin. 3 The epoxy compound has the formula The resin according to claim 1, which is a compound represented by (Y is S or SO ₂ , m is a number of 1 or more).