JPH0525247B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radically curable unsaturated alkyd having a novel structure useful for various uses such as paints, adhesives, molding materials, and FRP, and a method for producing the same.

[Conventional technology]

Currently, unsaturated polyester resins and vinyl ester resins are widely used as radical-curable resins that can be cured at room temperature.

However, as the uses of resins become more diverse, the performance required of the resins becomes more detailed and sophisticated, and it is often felt that existing resins are insufficient to meet these demands. For example, in the case of gel coat, which is commonly used as a coloring and surface protection layer for FRP, there is a movement to improve water resistance, alkali resistance, and corrosion resistance against specific chemicals without increasing costs.

Vinyl ester resins have extremely excellent water and chemical resistance, so naturally they can be used for this purpose, and in fact, their boiling resistance itself is extremely good, so they are generally used as gel coats. However, the workability required for gel coats, namely sprayability, thixotropy imparting properties,
There is a need for further improvement in various aspects such as the absence of color separation, and although efforts are being made to improve in line with these expectations, at this stage the desired results have not been obtained.

On the other hand, for unsaturated polyester resin, the bisphenol type polyester shown by the following formula Styrene solutions have become the mainstream gel coat for bathtubs because of their good workability. However, it has the drawback that its hot water resistance is inferior to that of vinyl ester resins, and it does not meet high demands.

[Problem that the invention seeks to solve]

As a result of intensive research to improve the various drawbacks of these existing resins, the present inventors discovered that an unsaturated alkyd with a new structure represented by the general formula below has excellent water resistance and
The present inventors have discovered that this resin has chemical resistance that is at least equal to or better than these existing resins, and is also superior in terms of workability, leading to the completion of the present invention.

[Means to solve the problem]

That is, the present invention is based on the general formula The object of the present invention is to provide a curable unsaturated alkyd, wherein n is an integer from 2 to 20.

Furthermore, the present invention provides general formula The epoxy resin represented by is reacted with phenol in an amount that eliminates the epoxy groups in the epoxy resin to obtain a reaction product [] is produced, and then the hydroxyl group in the reaction product [] is esterified with an α-β unsaturated polybasic acid or its anhydride. [Provided that n is an integer of 2 to 20] [Operation] The unsaturated alkyd of the present invention has a novel structure represented by the above general formula. Because it has a phenoxymethylene group in the side chain, it is bulky and has fewer double bonds per molecular weight, which has a positive effect on the boiling resistance and heat distortion temperature of the resin. Presumed. In addition, since the main chain of the unsaturated alkyd of the present invention is composed of repeating units in which bisphenol diglycidyl ether and α-β unsaturated polybasic acid are ester-bonded, it can be dissolved in styrene solution like bisphenol type polyester. The number of repeating units that are considered to provide excellent workability when used as When the curing property is poor and it is greater than 20, it becomes difficult to carry out the present invention.

The unsaturated alkyd according to the present invention can be used in paints, adhesives, etc. by dissolving it in a copolymerizable monomer (hereinafter referred to as monomer) that can copolymerize with unsaturated bonds in the molecule and curing it in the presence of a radical catalyst. It can be used for various purposes such as , molding materials, and FRP.

A method for synthesizing the unsaturated alkyd of the present invention is to further esterify the hydroxyl group produced by reacting a desired epoxy resin with phenol with an α-β unsaturated polybasic acid or its acid anhydride. .

An epoxy resin suitable for the present invention is one having the following structure and sold by Yuka Shell Co., Ltd. under the trade name YX-4000.

The ratio of epoxy groups to phenolic hydroxyl groups is 1 equivalent of epoxy groups to 1 equivalent of phenolic hydroxyl groups.
A suitable amount is 0.5 equivalent or less.

If the amount is less than 0.5 equivalent, gelation tends to occur when esterifying with an unsaturated polybasic acid or its acid anhydride. During the reaction, tertiary amines, such as benzyldimethylamine, tris(dimethylamino)phenol, or quaternary ammonium salts, which are generally used as curing accelerators for epoxy resins, are used to accelerate the reaction. is extremely effective.

Examples of α-β unsaturated polybasic acids or their acid anhydrides include maleic anhydride, maleic acid, and fumaric acid. It can also be modified with saturated polybasic acids.

Esterification is carried out in the usual manner, i.e. in an inert gas stream.
It is carried out at a temperature of 180-220°C. The unsaturated alkyd obtained by esterification can be dissolved in copolymerizable monomers such as styrene, vinyltoene, diallyl phthalate, diallyl terephthalate, and methacrylic acid esters, and can be used for various purposes. At this time, in order to prevent gelation, it is necessary to add a small amount (0.01 to 0.5 phr) of commonly used polymerization inhibitors such as polyhydric phenols and quinones.

It goes without saying that fillers, reinforcing materials, colorants, mold release agents, polymers, etc. can be used in combination, depending on the needs of the application.

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

Example: Into a separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas inlet tube, 380 g of YX-4000 from Yuka Ciel Co., Ltd. as an epoxy resin was added.
169g of phenol (0.9 equivalents of hydroxyl group per equivalent of epoxy group) and 1.5g of benzylmethylamine were charged, and when the temperature was raised to around 110℃, it rapidly generated heat, so it was cooled to prevent it from rising above 160℃. .

After reacting at 150 to 160°C for 5 hours, infrared analysis confirmed that the absorption of epoxy groups completely disappeared.

Next, add 110g of fumaric acid and place it in an inert air stream.
Esterification was accelerated at 190-210°C, stopped at an acid value of 11.4, and 0.1g of hydroquinone was added, poured into a metal vat, and cooled.

The obtained unsaturated alkyd [A] has a melting point of approximately 120
℃, dark reddish brown.

Molecular weight, approximately 5000.

100 parts of unsaturated alkyd [A] was ground and dissolved in 100 parts of styrene while heating at 70-80°C.

The obtained unsaturated polyester resin [B] has a viscosity of
It had 5.8 poise and 5 to 6 Gardner colors.

A mixture obtained by adding 2 parts of methylethyltone peroxide and 2 parts of cobalt naphthenate to 100 parts of unsaturated polyester resin [B] gelled in 20 minutes and slowly generated heat, reaching a maximum exothermic temperature of 157°C.

The heat distortion temperature of the cast product was 121°C.

A continuous boiling test was conducted on a casting plate measuring 5 cm x 5 cm and 3 mm thick, and no abnormalities were observed in appearance even after 2000 hours of boiling, indicating excellent water resistance.

In addition, there were no abnormalities in a continuous boiling test with a 10% caustic soda aqueous solution for up to 500 hours, and it also showed extremely good alkali resistance.

[Brief explanation of the drawing]

FIG. 1 shows an infrared spectrum of the reaction product of the epoxy resin and phenol obtained in Example 1. FIG. 2 shows an infrared spectrum of the unsaturated alkyd of the present invention obtained by the reaction of the above reaction product with fumaric acid.

Claims (1)

[Claims] 1. A curable unsaturated alkyd substantially represented by the following general formula: [However, n is an integer from 2 to 20]. 2 General formula The epoxy resin represented by is reacted with phenol in an amount that eliminates the epoxy groups in the epoxy resin to obtain a reaction product [] is produced, and then the hydroxyl group in the reaction product [] is esterified with an α-β unsaturated polybasic acid or its anhydride. A method for producing a curable unsaturated alkyd represented by (where n is an integer from 2 to 20).