JPH0134530B2 - - 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 requirements. 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, desired results have not been obtained at this stage.

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 for solving problems]

That is, the present invention is based on the general formula [However, R ₁ and R ₂ each represent hydrogen or a methyl group, n is 0 to 2, and m is 2 to 20
The present invention provides a curable unsaturated alkyd having the following integer:

Furthermore, the present invention relates to the general formula The epoxy resin represented by is reacted with cresol in an amount that eliminates the epoxy groups in the epoxy resin to form 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. The object of the present invention is to provide a method for producing a curable unsaturated alkyd represented by the formula (where R ₁ , R ₂ , n and m are the same as above).

[Effect]

The unsaturated alkyd of the present invention has a novel structure represented by the above general formula, and has a methylphenooxymethylene group in the side chain, so it is bulky.
Furthermore, the number of double bonds per molecular weight decreases, which is presumed to have a favorable effect on the boiling resistance and heat distortion temperature of the resin. 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. It is thought that this product will have excellent workability when used as a tool. The number of repeating units is 2 to 20 (equivalent to about 1,000 to 10,000 when converted to molecular weight); if the number of repeating units is smaller than 2, the curing properties of the resin are poor, and if it is larger than 20, it is difficult to implement the present invention. becomes.

The unsaturated alkyd according to the present invention can be used in paints, adhesives, molding agent,
It can be used for various purposes such as FPR.

The method for synthesizing the unsaturated alkyd of the present invention involves reacting a bisphenol diglycidyl ether type epoxy resin with cresol, and then converting the hydroxyl group in the reaction product into an α-β unsaturated polybasic acid or its anhydride. An example of this method is esterification. The flow is shown below using a typical example.

The epoxy resin used in the present invention is of the phenyl glycidyl ether type, commonly referred to as the so-called bisphenol type.

For example, the type shown by the following general formula synthesized from bisphenol A and epchlorohydrin, It is preferable that n be in the range of 0 to 2, and there is no need to increase the number of repeating units.

Furthermore, a methylene-bisphenyl glycidyl ether type epoxy resin commonly referred to as a bisphenol F type epoxy resin can also be used.

Examples of the cresol to be reacted with the epoxy resin include ortho-cresol, meta-cresol, and para-cresol.

In the present invention, mixtures of these can also be suitably used.

The reaction ratio of epoxy resin and cresol is 1 equivalent of epoxy group to 1 equivalent of phenolic hydroxyl group.
A suitable amount is 0.5 equivalent or less.

If it is less than 0.5 equivalent, it is not preferable because it tends to gel when esterified with an unsaturated polybasic acid or its acid anhydride.

During the reaction, tertiary amines that are generally used as curing accelerators for epoxy resins, such as benzyldimethylamine and tris(dimethylamino), are used.
The use of phenol, quaternary ammonium salt, etc. is highly effective in promoting the reaction.

Examples of the α-β unsaturated polybasic acid or its acid anhydride used in the present invention include maleic anhydride, maleic acid, and fumaric acid. At that time, it can also be modified with a small amount of saturated polybasic acid.

Esterification is carried out in the usual manner, i.e. in an inert gas stream.
It is carried out at a temperature of about 180 to 220 degrees Celsius.

The unsaturated alkyd obtained by esterification can be dissolved in copolymerizable monomers such as styrene, vinyltoluene, diallyl phthalate, diallyl terephthalate, methacrylic acid esters, etc., and can be provided for various uses.

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.

〔Example〕

Next, examples will be shown below to help understand the present invention. In the examples, parts indicate parts by weight.

Example 1 Into a separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas inlet tube, 370% of Epicoat 827 from Yuka Ciel Co., Ltd. was added as an epoxy resin.
g, para-cresol 195g (ratio of epoxy group to phenolic hydroxyl group is 1:0.9), and benzyldimethylamine 1.5g, and when heated, it rapidly generates heat when the temperature exceeds 110℃, so cool it and raise it to 160℃ or higher. I prevented it from happening.

The reaction was then carried out at 150-160°C for 5 hours, and as a result of infrared analysis, it was confirmed that the free epoxy groups had completely disappeared (see Figure 1).

Next, add 110 g of fumaric acid and add 200 g of fumaric acid to
After heating to 210°C for 6 hours, the acid value became 19.6, so 0.13g of hydroquinone was added and poured into a metal vat to solidify. Yellowish brown, melting point approximately 110-115℃
of unsaturated alkyd A was obtained. The infrared absorption spectrum is shown in FIG. Average molecular weight is approximately 3200
It was hot.

Grind 100 parts of unsaturated alkyd A, add 100 parts of styrene to it, and heat and stir at 60 to 70°C to obtain unsaturated polyester resin B with a Gardner color number of 2 to 2.
3. Obtained with a viscosity of 9.6 poise.

A system in which 2 parts of methyl ethyl ketone peroxide and 2 parts of cobalt naphthenate were added to 100 parts of unsaturated polyester resin B gelled in 49 minutes and reached a maximum temperature of 139° C. while slowly generating heat. The heat distortion temperature of the cast product was 108°C.

A continuous boiling test was conducted on a casting plate measuring 5 cm x 5 cm and 3 mm thick, and no abnormality was observed in the 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.

Example 2 In a separable flask equipped with a stirrer, a fractionating condenser, a gas inlet tube, and a thermometer, 340 g of Epicote 807 from Yuka Ciel Co., Ltd. and 173 g of metacresol were added as bisphenol F-type epoxy resin.
(The ratio of epoxy groups and phenolic hydroxyl groups is 1:1.
0.8) When 1.5g of trimethylbenzylammonium chloride is charged and heated, it starts to generate heat rapidly after reaching 110℃, so it is cooled to 160℃.
I kept it below. When kept at 150-160℃ for 5 hours,
As a result of infrared analysis, free epoxy groups completely disappeared.

Next, add 98g of maleic anhydride and heat at 200-215℃.
When esterified for 6 hours in an inert gas stream, the acid value is
11.4, so add 0.1g of hydroquinone,
It was poured into a metal vat and allowed to solidify.

An unsaturated alkyd C was obtained which was yellowish brown in color and had a melting point of about 105-110°C. The average molecular weight was approximately 4,500.

Unsaturated polyester resin D obtained by pulverizing 100 parts of unsaturated alkyd C and dissolving it in 110 parts of p-methylstyrene while heating at 60 to 70 DEG C. had a Hazen color number of 500 and a viscosity of 9.5 poise.

A system in which 2 parts of methyl ethyl ketone peroxide, 1 part of cobalt naphthenate, and 0.2 parts of dimethylaniline are added to 100 parts of unsaturated polyester resin D is as follows:
After gelation at room temperature for about 40 minutes, it slowly generated heat, reaching a maximum exothermic temperature of 149°C.

The heat distortion temperature of the cast product was 104°C.

[Brief explanation of drawings]

FIG. 1 shows an infrared spectrum of the reaction product of the epoxy resin obtained in Example 1 and p-cresol. 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, R ₁ and R ₂ each represent hydrogen or a methyl group, n is 0 to 2, and m is 2 to 20
]. The epoxy resin represented by is reacted with cresol in an amount that eliminates the epoxy groups in the epoxy resin to form 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 R ₁ , R ₂ , n and m are the same as above).