JPH0347648B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Application Field The present invention relates to a method for producing a radically polymerizable urethane oligomer. More specifically, the compound of the present invention can be homopolymerized or copolymerized with an appropriate reactive monomer using heat, ultraviolet rays, electron beams, etc., and can be used in paints, inks, adhesives, yeast immobilization, dentistry, etc. In addition to being used as a filler, it is also useful as printing plate material, photoresist, resist ink for printed wiring, etc. due to its property of curing with ultraviolet rays. B. Prior Art Radically polymerizable urethane oligomers are often used particularly as ultraviolet curable prepolymers. An ultraviolet curable resin is a resin that changes from a liquid state to a solid state when exposed to ultraviolet rays, and is usually composed of a reactive prepolymer, a reactive diluent, and a photopolymerization initiator. The mainstream of these reactive prepolymers is acrylic prepolymers. Acrylic prepolymers include polyester acrylate types, epoxy acrylate types, urethane acrylate types, etc., and each prepolymer is used as appropriate depending on the function and application. Among them, the urethane acrylate type is
41708, Japanese Patent Publication No. 55-8013, etc., it has better air curing properties than other prepolymers,
In the future, urethane acrylate is expected to be developed because it forms a strong coating film and has excellent adhesion to iron and glass, and on the other hand, it can be expected to develop urethane acrylates with various different structures depending on the reactivity of isocyanate. is also seen as promising. C Problems to be Solved by the Invention As mentioned above, when producing urethane acrylate, various molecular designs are possible due to the high reactivity of isocyanate, and it has many possibilities, but in reality There are only a few types of urethane acrylate commercially available. Among these, there is currently a demand for urethane acrylates that have better hardness, better adhesion to iron surfaces, and better flexibility than conventional ones. D. Means for Solving the Problems In view of the above circumstances, the inventors of the present invention have made extensive studies and found that the following reaction products of component (a), component (b), and product (c) are: Isocyanate (b) Spiroglycol (c) Compound represented by the following general formula () (In the formula, R ₁ is H or CH ₃ , n = 1 to 10) It was discovered that the radically polymerizable urethane oligomer produces a cured product with excellent hardness, adhesion to iron surfaces, and flexibility. He came up with an invention. The present inventors previously invented an oligomer having a structure similar to this substance and filed a patent application (Japanese Patent Application No. 147,133/1982). The present invention further improves this material and provides a method for producing a urethane oligomer that exhibits particularly excellent performance not only in hardness and adhesion to iron surfaces but also in flexibility. The radically polymerizable urethane oligomer of the present invention is structured, for example, as follows. polyvalent isocyanate and spiroglycol,
Ratio of hydroxyl groups per isocyanate group (OH/
NCO)≦1 (mol/mol) to produce a terminal isocyanate oligomer. Next, polycaprolactone (meth)acrylate [general formula ()] is added at a ratio of hydroxyl groups per isocyanate group (OH/NCO)≦1 and reacted. The reaction is preferably carried out in a solvent such as tetrahydrofuran or methyl ethyl ketone. As a reaction catalyst,
Examples include metal salts such as dibutyltin dilaurate and lead naphthenate, and tertiary amines. In addition, as polymerization inhibitors, hydroquinone, p-benzoquinone, p-
- Cresol etc. may be added. Reaction temperature is 80℃
The following are preferred. Examples of the polyvalent isocyanate include 2,4-tolylene diisocyanate, 2,6-tritenediisocyanate, a mixture of 2,4 and 2,6-tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, m-phenylene diisocyanate, and xylene diisocyanate. Diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate ester, 1,
4-cyclohexylene diisocyanate, 4,4'
-dicyclohexylmethane diisocyanate,
3,3'-dimethyl-4,4-biphenylene diisocyanate, 3,3-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dichloro-
4,4'-biphenylene diisocyanate, 1,5
- Naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, isophorone diisocyanate, etc. are used. E Examples Examples are shown below. Example 1 174 g (1.0 mol) of 2,4-tolylene diisocyanate (TDI) [manufactured by Tokyo Kasei Co., Ltd.] was placed in a four-necked flask equipped with a thermometer, a cooling tube, and a stirring device.
Spiroglycol [manufactured by Mitsubishi Gas Chemical Co., Ltd.] 152g
(0.5 mol) and tetrahydrofuran (THF) 500
Added ml. Next, dibutyltin dilaurate
Heat was generated at the same time as the reaction started when 0.2 g was added and heated, but the maximum temperature during the reaction was 72°C. After the temperature rise due to heat generation had ended, stirring was continued at 60°C for about 2 hours. 0.02 g of hydroquinone monomethyl ether (MEHQ) and a compound of the following formula were added to the obtained reaction product. (Product name: Plaxel FA-1) [manufactured by Daicel Chemical Industries, Ltd.] 230 g (1.0 mol) was added. In this case as well, the maximum temperature during the reaction was 70°C. After the exotherm had ended, stirring was continued at 60°C for about 1 hour. The obtained reaction product was dried under reduced pressure (5 mmHg) at 40° C. for 3 hours after THF was distilled off using an evaporator to obtain a solid pale yellow substance. The characteristic IR peak of this pale yellow substance is shown below. 3330cm ^-1 Absorption due to stretching vibration of N-H 2960cm ^-1 2830cm ^-1 Stretching vibration of aliphatic C-H Around 1720cm ^-1 C=O of urethane bond and ester bond of acryloyl group 1610cm ^-1 1590cm ^-1 Benzene nucleus C =C stretching vibration Absorption of isocyanate groups at 2270 cm ^-1 was not observed at all. Example 2 The 2,4-tolylene diisocyanate of Example 1 was converted into isophorone diisocyanate (IPDI),
In addition, Plaxel FA-1 is a compound of the following formula. (Product name: Plaxel FA5) [Daicel Chemical Industries
Co., Ltd.], except for the same procedure as in Example 1. As a result, a transparent viscous substance was obtained. [Effects of the Invention] Using the urethane oligomers obtained in Examples 1 and 2, photocurable resins were obtained with the formulations shown in Table 1. Table-1 Part by weight Urethane oligomer 50 Polyethylene glycol #400 diacrylate
20 Tetrahydrofurfuryl acrylate 24 Methyl o-benzoylbenzoate 6 The resin obtained with the formulation shown in Table 1 was applied onto a steel plate, and exposed to light for 10 seconds directly under a high-pressure mercury lamp with an output of 120 W/cm for 10 seconds to form a coating film. Obtained. Table 2 shows the physical property test results of the obtained coating film. 【table】

Claims (1)

[Scope of Claims] 1. A method for producing a radically polymerizable urethane oligomer, characterized by reacting the following components (a), (b), and (c): (a) polyvalent isocyanate (b) spiroglycol (c) Compound represented by the following general formula () (In the formula, R ₁ is H or CH ₃ , n = 1 to 10)