JPS62109815A - Production of curable resin - Google Patents

Abstract

PURPOSE:To obtain the titled resin which is freely curable at normal temperature or under heating and capable of forming a protecting smooth film of coating in a micron unit on the surface of a metal, by reacting a phenoxy resin with an unsaturated isocyanate obtained by a specific method. CONSTITUTION:Firstly, a polyfunctional isocyanate (preferably 2,4-tolylene diisocyanate, etc.) containing plural NCO groups is reacted with an unsaturated alcohol containing an unsaturated group and a hydroxyl group, to give an unsaturated isocyanate containing a NCO group and the unsaturated group. Then, a phenoxy resin having >=20 polymerization degree is reacted with the unsaturated isocyanate in such a way that the amount of NCO group in the unsaturated isocyanate is >=0.01 equivalent based on 1 equivalent hydroxyl group in the phenoxy group, to give the aimed resin. A reaction product of acrylic acid with an alkylene monoepoxide is used as the unsaturated alcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a curable resin that can be freely cured at room temperature or under heating and is useful for various uses.

[Conventional technology]

There are various types of resins that can be cured, especially those that cure by radical polymerization reactions, such as unsaturated polyester resins, vinyl ester resins (epoxy-acrylates), various oligoacrylates, and diallyl phthalate sol polymers, each of which has its own characteristics in its application field. It is utilized and widely used.

However, with the diversification and sophistication of required performance in each application field, these existing resins may not be able to fully satisfy the required performance.

For example, it is extremely difficult to uniformly coat a metal surface in microns and cure it to form a smooth protective coating layer using the existing radical-curing resins, which have molecular weights that belong to oligomers. It is.

[Problem that the invention seeks to solve]

In view of the above situation, the present inventors have been conducting various studies on the synthesis of radical-curable resins that can be used in applications where existing resins are unsatisfactory. We were able to complete the present invention by learning that curable resins can satisfy some of the diversification and sophistication of performance required.

[Means for solving problems]

That is, the present invention provides a phenoxy resin with a degree of polymerization of 20 or more (corresponding to a molecular weight of 5000 or more, preferably 1000 or more), and a polyhydric isocyanate and an unsaturated monoalcohol, which are obtained by reacting a polyvalent isocyanate and an unsaturated monoalcohol. An unsaturated isocyanate having one isocyanate group and at least one unsaturated bond is mixed with 0 isocyanate groups of the unsaturated isocyanate per equivalent of hydroxyl group of the phenoxy resin.
It is better to react in amounts of 0.01 equivalent or more.

[Effect]

For reference, typical methods of the present invention are illustrated with chemical formulas.

(a) Synthesis of unsaturated isocyanate Diisocyanate 2-Hydroxyethyl methacrylate Unsaturated isocyanate As mentioned above, the hydroxyl group of the phenoxy group is bonded to the methacryloyl group via two urethane bonds, and the unsaturated isocyanate is attached to the polymer side chain. It has a saturated bond added to it.

Since the side chain acryloyl group introduced by such an operation can be crosslinked, it is possible to convert phenoxy resin, which is originally a thermoplastic polymer, into a thermosetting type, imparting heat resistance, improving chemical resistance, It will be useful for etc.

The phenoxy resin used in the present invention is a polymer represented by the following general formula, and has a degree of polymerization of 20 or more (average molecular weight of 5,000 or more, preferably 10,000 or more).

CH.

Ha However, R=, -H or -CH2-CH-CH2CH2 CH.

Generally, those in the range of 30,000 to 100,000 are commercially available, and in the present invention, these are dissolved as they are in the necessary solvent, and
Can be used for reactions with unsaturated isocyanates. .

If the molecular weight is less than 500, film forming properties before curing are not necessarily sufficient.

In principle, 1 mol of unsaturated monoalcohol is used for 1 mol of diisocyanate in the production of unsaturated isocyanate, but when two isocyanates are used, such as 2,4-tolylene diisocyanate, Even if there is a significant difference in reactivity between the isocyanate groups, the unsaturated isocyanate depicted in the model is not removed alone; the following three types of diisocyanates, unsaturated isocyanates, and oligomers are usually used. A mixture of acrylates is formed.

0 Unsaturated isocyanate.

Oligoacrylates Undesirable among these components are free diisocyanates, which, if left behind, can cause dulling or abnormally increase viscosity, making handling difficult.

When phenoxy resin is used as a component, the residual amount of diisocyanate must be 0.1 (wt%) or less.

In order to remove free diisocyanate, it is necessary to increase the amount of the unsaturated monoalcohol component to more than a specified number of moles, or to remove the diisocyanate by distillation under reduced pressure after the reaction is completed.

However, if the unsaturated monoalcohol has a (meth)acryloyl group, reduced pressure at high temperature will polymerize the (meth)acryloyl group, resulting in celification. Measures such as depressurization are required.

Oligoacrylates, which are another so-called by-product, do not impede the invention.

If its abundance is determined, it will be useful for improving physical properties, for example, increasing heat distortion temperature.

Therefore, a practically easy method for producing unsaturated 11th isocyanate is to use 1 mol or more of unsaturated monoalcohol per 1 mol of diisocyanate, and the most suitable molar ratio is 1.2 mol or more and 1.2 mol or more. It is 5 moles or less.

For example, when 1.2 mol of unsaturated monoalcohol is used per 1 mol of diisocyanate, the following mixture is obtained.

(a) Unsaturated isocyanate (b) Oligoacrylate This can be used as is for reaction with phenoxy resin.

Examples of diisocyanates for forming unsaturated isocyanates include the following types.

2.4-tolylene diisocyanate, mixture of 2.4-tolylene diisocyanate and 2.6-)lylene diisocyanate, 4-rough phenylene diisocyanate, diphenylmethane diisocyanate, 1.5-naphthylene diisocyanate Isocyanate, xylylene diisocyanate,
Hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, inphorone diisocyanate.

The preferred type is 2,4-tolylene diisocyanate;
There is a difference in the reactivity of two isocyanate groups, such as inphorone diisocyanate.

Furthermore, examples of the unsaturated monoalcohol to be used include those having a (meth)acryloyl group and a hydroxyl group in one molecule, which are obtained by reacting acrylic acid or methacrylic acid with alkylene sonoepoxide.

In addition, allyl alcohol can also be used.

The reaction ratio of phenoxy resin and unsaturated isocyanate is: isocyanate group (i.e., unsaturated isocyanate) o, oi per equivalent of hydroxyl group of phenoxy resin.
It is more than an equivalent, but preferably 0.1 equivalent or more and 1 equivalent or less. If the amount is less than 0.01 equivalent, it is difficult to make it thermosetting.

During the reaction, it is necessary to use a polymerization inhibitor to prevent ketalization, and it is advantageous to use a reaction accelerator such as a tertiary amine or an organic tin compound to shorten the reaction time.

The curable resin composition obtained by the method of the present invention is
It can be cured by using a radical generating catalyst such as an organic peroxide and, if necessary, a curing accelerator.

It goes without saying that the curable resin according to the present invention may be used in combination with colorants, reinforcing materials, fillers, mold release agents, etc., as necessary.

〔Example〕

Next, examples will be shown below to help understand the present invention.

Example 1 Production of unsaturated incyaner (A) 2.4-
Tolylene diisocyanate 174ji (1 mol) was charged, and 2-hydroxyethyl methacrylate containing 2001) pm benzoquinone-containing 13og (
1 mol) was added dropwise.

Since the temperature rises, the reaction mixture is cooled as necessary so that the reaction occurs at around 60°C.

After reacting at 60° C. for 8 hours, it was determined that free hydroxyl groups had disappeared as a result of infrared analysis.

Change the reflux condenser to a fractionation condenser, add 0.1F of phenothiazine, and add 2 to 3 rran in oxygen stream.
Hg, vacuum to 90°C. After 3 hours, gas chromatography analysis revealed that the amount of free diisocyanate was approximately 0.06 (
It will be discontinued once it is recognized that it is $).

Pale reddish brown unsaturated iso7anate A was obtained in the form of a viscous liquid.

Production of curable resin (B) As a phenoxy resin, Phenoto) YP manufactured by Toto Kasei Co., Ltd.
-50 (weight average molecular weight approximately 41,000) dissolved in methyl ethyl ketone 716y, 60 g of unsaturated isocyanate (5) (0.2 equivalent of isocyanate group per equivalent of hydroxyl group of phenoxy resin)
, 0.5 g of diptyltin nolaurate, and heated to 60°C.
After reacting for a while, infrared analysis confirmed that free isocyanate groups disappeared.

A methyl ethyl keto/molten tL (abbreviated as resin B) of phenoxy resin having a (meth)acryloyl group in the side chain was obtained with a reddish brown color and a viscosity of about 200 poise.

Resin B: 100 parts by weight or less, 0.5 parts of 328E from Kayaku Nouri Co., Ltd. as a curing agent, and 0.0 parts of cobalt naphthenate.
．． Add 2 parts and 50 parts of methyl ethyl ketone onto Vinprite steel plate. I painted it with a percoater so that it was IN thickness.

The coating film cured for 12 hours at 60℃ and 2 hours at 120℃ is smooth, has a pencil hardness of 3H, and has a goblin adhesion test).
It was excellent at 100/Zoo.

Furthermore, even when the coating film was immersed in methyl ethyl ketone, no peeling due to dissolution or swelling was observed, and it was confirmed that the coating film had hardened.

Example 2 Production of unsaturated incyaner (C) Stirrer, reflux condenser, dropping funnel, thermometer, t-
Attached 2! 7 Parapur Flasconi, Methyl Ethyl Ketone 512Ii, Isophoro/Diisocyanate 225. F(
1 mole of 7-enylglycisol ether and acrylic acid (1 mole to 1 mole adduct 2709 (1 mole of isocyanate, (equivalent to .2 mol) was added dropwise.

When the reaction was carried out at 60° C. for 6 hours after the completion of the dropwise addition, it was determined that the free hydroxyl groups had disappeared as a result of infrared analysis.

A pale yellow-brown unsaturated isonener) (C) (approximately 50 methyl ethyl ketone solution) was obtained.

Production of curable resin) In a Mitsuro Ninuma flask equipped with a stirrer, a reflux condenser, and a thermometer, as a phenoxy resin, Epicoat 53f (B35 (methyl ethyl ketone solution 34-36% solid content, molecular weight approx. 55,000), unsaturated isocyanate (c), 4ooy (isocyanate group, approximately 0.3 equivalent per equivalent of hydroxyl group of phenoxy resin), hydroquinone 0.1,
9. Add dibutyltin nolaurate 0.5.9, 60
React at ℃ for 8 hours.

As a result of infrared analysis, it was confirmed that the isocyanate groups had completely disappeared.

The resulting curable resin (D) has a yellowish brown color and a viscosity of approximately 13
It was 0 poise.

To 100 parts of resin (D), 30 parts of methyl ethyl ketone, 1 part of cumene hydroglycoxide, and 0.2 parts of cobalt naphthenate were added, and the mixture was coated on a Handerite steel plate to a thickness of 0.1.

After heating at 60°C for 12 hours and 120°C for 2 hours, the coating film was smooth, had a hardness of 3 to 4H, and had a goblin adhesion test of 100/100. Even after being immersed in methyl ethyl ketone for one day, there were no abnormalities, and no dissolution or swelling was observed. .

It was confirmed that it had hardened.

〔Effect of the invention〕

The curable resin produced by the method of the present invention can be freely cured at room temperature or under heating, and is useful for various uses. In particular, the ability to form a smooth protective coating layer by coating and curing a metal surface in micron units is an effect not found with conventionally known curable resins.

Claims (1)

[Claims] A phenoxy resin with a degree of polymerization of 20 or more, and a polyvalent isocyanate having at least 2 isocyanate groups in one molecule, which has 0.01 equivalent or more of isocyanate groups per 1 equivalent of hydroxyl group of the phenoxy resin. An unsaturated alcohol having at least one isocyanate group and at least one unsaturated group in the molecule obtained by reaction with an unsaturated alcohol having at least one unsaturated group and a hydroxyl group per minute. A method for producing a curable resin by reacting it with a saturated isocyanate.