JPH0317850B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing unsaturated polyester that has various properties that are even better than those of the prior art. [Prior art] Unsaturated polyester resin obtained by reacting polybasic acid, polyhydric alcohol, and polyhydric alcohol allyl ether is used as an air-drying paint for furniture, interior materials,
It is widely used for painting household items, etc. This paint has excellent properties in terms of curing speed, drying speed, abrasiveness, coating hardness, water resistance, etc., and as one of the most practical paints, the demand for it is increasing. [Problems to be solved by the invention] However, in recent years, as technological innovations and social demands have become more sophisticated, the above-mentioned properties of such paints have been further improved, and at the same time corrosion resistance has also been improved when used in humid and wet areas. The applied paint is required. [Means for Solving the Problems] However, in order to solve the above problems, the present inventors have
We have conducted extensive research into air-drying paints. the result,
An epoxy resin-modified unsaturated polyester in which an unsaturated polyester having an allyl ether group and a carboxyl group (hereinafter abbreviated as allyl ether group-containing polyester) is bonded to the epoxy group in a bifunctional bisphenol A type epoxy resin is different from conventional products. In comparison, it was found that the corrosion resistance and coating hardness were extremely superior, and the present invention was completed. The bifunctional bisphenol A type epoxy resin (hereinafter simply referred to as epoxy resin) in the present invention is a compound having the following structural formula, in which n is usually appropriately selected from the range of 0 to 3. In addition, the epoxy equivalent of the epoxy resin is 100~
500, preferably in the range of 180 to 300. If it is less than 100, the glass transition temperature will be too low and the drying rate will tend to decrease; if it is more than 500, allyl ether groups and unsaturated groups will be removed when producing the unsaturated polyester of the present invention. It is not preferable because the functional group equivalent of is too low and the curing speed and anticorrosion properties are lowered. The allyl ether group-containing polyester used in the present invention must contain a free carboxyl group in its molecule, and the carboxyl group is reacted with the epoxy group in the epoxy resin. In addition, it is essential that the polyester always has an allyl ether group in the resin, and even if it is a general unsaturated polyester without such a group or an allyl group, it cannot be condensed with a monohydric alcohol such as allyl alcohol. If it is introduced into the resin as a component, the effects of the present invention cannot be achieved at all. Although such unsaturated polyesters can be produced by any method, they are usually produced by condensing polybasic acids, polyhydric alcohols, and polyhydric alcohol allyl ethers to produce allyl ether group-containing unsaturated polyesters in which at least one free carboxyl group remains in the molecule. Prepare a saturated polyester. As the polybasic acid, unsaturated polybasic acids such as maleic acid, fumaric acid, itaconic acid, cistraconic acid and anhydrides thereof are used, and if necessary, phthalic acid, isophthalic acid,
Saturated polybasic acids such as terephthalic acid, hettic acid, adipic acid, sedicic acid, succinic acid, azelaic acid, and anhydrides thereof can also be used in combination. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, trimethylene glycol, triethylene glycol, trimethylolethane, trimethylolpropane, dihydroxypentadiene, pentaerythritol, glycerin, diglycerin, ditrimethylolpropane, etc. It will be done. Examples of polyhydric alcohol allyl ethers include glycerin monoallyl ether, trimethylolpropane moallyl ether, trimethylolpropane diallyl ether, trimethylolethane monoallyl ether, trimethylolethane diallyl ether, pentaerythritol monoallyl ether, pentaerythritol diallyl ether, and pentaerythritol. triallyl ether, 1,
Examples include 2,6-hexanetriol monoallyl ether, 1,2,6-hexanetriol diallyl ether, sorbitan monoallyl ether, sorbitan diallyl ether, but the present invention is not limited to these compounds. The desired epoxy resin-modified polyester can be obtained by reacting the allyl ether group-containing polyester with an epoxy resin. Specifically, it is common to prepare an allyl ether group-containing unsaturated polyester in advance, mix it with an epoxy resin, and react it. During the reaction between the epoxy resin and the allyl ether group-containing polyester, a small amount of 2-hydroxyethyl para-toluidine, 2-methylimidazole, trimethylbenzylammonium chloride, etc. is added as a catalyst. Reaction temperature is 50~
150°C, preferably in the range of 70-120°C. As described above, by reacting the allyl ether group-containing polyester with the epoxy resin, the unsaturated polyester of the present invention contains bisphenol cores, allyl ether groups, and unsaturated polybasic acids such as maleic anhydride. An acid double bond will be present. The presence of these three components makes it possible to obtain excellent performance in that corrosion resistance, coating hardness, and corrosion resistance are significantly improved without deteriorating the various performances of conventional air-drying paints. In the above epoxy resin-modified unsaturated polyester, the epoxy resin component is 20% of the total polymer.
The objective can be sufficiently achieved if the content is between 80% and 80% by weight, but the anticorrosive properties are more preferably achieved in the range of 25% to 70% by weight. Allyl ether is selected from a range of 5 to 20% by weight based on the total polymer. When the epoxy resin component is less than 20% by weight, the hardness of the coating film tends to decrease, and when it is used in excess of 80% by weight, the viscosity becomes too high, which remains a practical problem. The molecular weight of the epoxy resin-modified unsaturated polyester of the present invention is 800 to 4000, more preferably 1000 to 4000.
A range of 3000 is preferred. If the molecular weight is less than 800, the coating viscosity will be too low, resulting in a decrease in curing speed and corrosion resistance, and if it is more than 4000, the viscosity will be too high.
If styrene or the like is not used in large quantities, the viscosity of the coating will not be maintained, resulting in a decrease in curing speed and corrosion resistance, so it should be avoided. Furthermore, when the unsaturated polyester is used for coatings, it is generally mixed with a polymerizable monomer. Polymerizable monomers include styrene, vinyltoluene, chlorostyrene, α-methylstyrene, divinylbenzene, (meth)acrylic acid ester, glycidyl (meth)acrylate, vinyl acetate, diallyl phthalate, triallyl cyanurate, and trimethylolpropane. tri(meth)acrylate, tung oil,
Examples include linseed oil, soybean oil, cottonseed oil, safflower oil, and coconut oil. When used as a coating material, additives such as pigments, fillers, curing agents, curing accelerators, diluents, and thermoplastic resins may be added. Examples of pigments include titanium white, cyanine blue, cream yellow, watching red, red iron, carbon black, and aniline black. As a curing agent, methyl ethyl ketone peroxide, cyclohexanone peroxide, benzoyl peroxide, dicumyl peroxide,
Examples include tertiary butyl perbenzoate. Examples of the curing accelerator include cobalt octylate and manganese naphthenate. Examples of the diluent include ethyl acetate, toluene, xylene, methanol, ethanol, butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cellosolve, diacetone alcohol, and the like. Thermoplastic resins include cellulose acetate butyrate, nitrocellulose, vinyl chloride resin,
Examples include vinyl acetate resin, acrylic resin, copolymers thereof, butylated melamine, butylated urea, and the like. Other additives include phosphoric acid, tartaric acid, phosphorous acid, oils and fats, silicone oil, surfactants, paraffin wax, and the like. [Function] The epoxy resin-modified unsaturated polyester of the present invention is particularly useful as a paint, and can be used in any location. For example, target objects include wood coatings (furniture, musical instruments, etc.), automobile repair putty, FRP molding, and cast molding.One of the excellent features of the present invention is that it has very good corrosion resistance, so it can be used as heavy-duty anticorrosive flake coating paint, FRP. Ideal for gel coat coating of molded products. In addition to paints, it can also be used appropriately for adhesives, molded products, etc. [Example] The present invention will be specifically described below with reference to Examples. In addition, all "%" in the examples are based on weight. Example 1 0.45 mol of glycerin allyl ether, 1.0 mol of maleic anhydride, and 0.5 mol of ethylene glycol were charged and reacted for 6 hours at a temperature of 180°C to obtain an allyl ether group-containing polyester. To this was added 0.5 mol of bisphenol A diglycidyl ether (n=2) as an epoxy resin component, and 0.3% of 2-hydroxy paratoluidine was added to the total system, and the mixture was reacted at 90°C for 1 hour. Total 2.5%
After adding methanol and reacting for an additional hour,
Depressurize at 10mmHg for 30 minutes and dilute with styrene to obtain a resin content of 60%, acid value of 18mgKOH/g, and viscosity.
An epoxy resin-modified unsaturated polyester of 3000 cps and an epoxy resin component content of 60% based on the total polymer was obtained. To this was added 0.03% hydroquinone as a polymerization inhibitor, and the performance when used in paint was evaluated by the method described below. Example 2 Trimethylolpropane diallyl ether 0.25 as a raw material for allyl ether group-containing polyester
mol, maleic anhydride 0.7 mol, isophthalic acid 0.3
mol, one using 0.5 mol of propylene glycol and bisphenol A as an epoxy resin component
Using 0.5 mol of diglycidyl ether (n = 2), the resin content was 60% and the acid value was
An epoxy resin-modified unsaturated polyester having a viscosity of 15 mgKOH/g, a viscosity of 2500 cps, and an epoxy resin component content of 55% based on the total polymer was obtained and used as a paint. Example 3 In Example 1, an allyl ether group-containing unsaturated polyester having a composition of 0.8 mol of diallylpentaerythritol, 2.5 mol of maleic anhydride, and 1.4 mol of ethylene glycol and 1 mol of bisphenol A diglycidyl ether (n=0) were added. Same as the same example except that resin content 60%, acid value 3.5KOH
An epoxy resin-modified unsaturated polyester having a viscosity of 2000 cps and an epoxy resin component content of 25% based on the total polymer was obtained and used as a paint. The results of Examples 1 to 3 are summarized in a table. Control Example 1 Instead of the epoxy resin-modified unsaturated polyester used in Example 1, an unsaturated polyester consisting of 1.0 mol of maleic anhydride, 0.5 mol of hydrogenated bisphenol A, 0.2 mol of propylene glycol, and 0.4 mol of ethylene glycol was used as a raw material. This was diluted with styrene to give a resin content of 60% and an acid value of 22mgKOH/g.
A resin solution having a viscosity of 3000 cps was obtained and used as a paint in the same manner as in Example 1. Control Example 2 Instead of the epoxy resin-modified unsaturated polyester used in Example 1, an allyl ether group-containing unsaturated polyester consisting of 0.25 mol of trimethylolpropane diallyl ether, 1.0 mol of maleic anhydride, 0.5 mol of propylene glycol, and 0.5 mol of ethylene glycol was used. Using saturated polyester as a raw material, it is diluted with styrene to produce a resin with a resin content of 60% and an acid value of 20mg/KOH/
A resin solution with a viscosity of 2100 cps was obtained and used as a paint in the same manner as in Example 1. Control Example 3 Instead of the allyl ether group-containing unsaturated polyester used in Example 1, an allyl ether group-free unsaturated polyester with a resin composition of 1.0 mol of maleic anhydride, 0.6 mol of ethylene glycol, and 0.4 mol of propylene glycol was used. Then, 0.5 mol of bisphenol A glycidyl ether (n = 0) was charged and the reaction was carried out according to Example 1, and then diluted with styrene to reduce the resin content to 60.
%, an acid value of 7 mgKOH/g, a viscosity of 2300 cps, and an epoxy resin component of 35% based on the total polymer. A resin solution was obtained and used as a paint in the same manner as in Example 1. Control Example 4 Instead of the allyl ether group-containing unsaturated polyester used in Example 1, an unsaturated polyester resin with a resin composition of 1.0 mol of maleic anhydride, 0.3 mol of ethylene glycol, 0.4 mol of propylene glycol, and 0.3 mol of allyl ether was used. Then, 0.5 mol of bisphenol A glycidyl ester (where n=) was charged, and the reaction was carried out according to Example 1, resulting in a resin content of 60%, an acid value of 3.5 mgKOH/g,
A resin solution having a viscosity of 2800 cps and an epoxy resin component of 50% of the total polymer was obtained and used as a paint in the same manner as in Example 1. The performance of the paints of Control Examples 1 to 4 is summarized in the table. Performance evaluation was performed using the following method. 1 Surface drying property After diluting the resulting paint with a resin content of 60% to 50% with a styrene solution, 0.5% cobalt octenoate (cobalt content 8%) and Burmek N (methyl ethyl ketone peroxide 55% manufactured by NOF Co., Ltd.) were added. solution) was added at 1%. Apply 0.5mm of this onto a glass plate with an applicator and check that it is dry to the touch.
Carbon paper was placed on the painted surface, a load of 5 kg was applied to a 5 cm x 5 cm width, and the presence or absence of tack was determined based on the degree of carbon remaining. In a completely tack-free state, no carbon transfer is observed. 2 Pencil hardness Based on JIS K5401, the back of the pencil was erased with an eraser, and the hardness value is shown when there are no scratches. 3 Corrosion resistance The state of change in the painted surface and the weight change (%) of the test piece were investigated under the conditions described below. Pure water resistance: 72 hours immersion in pure water at 90°C Acid resistance: 6 months in 30% hydrochloric acid (at room temperature) Alkali resistance: 6 months in 50% sodium hydroxide aqueous solution (at room temperature)

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Claims (1)

[Claims] 1. A method for producing an epoxy resin-modified unsaturated polyester, which comprises bonding an unsaturated polyester having an allyl ether group and a carboxyl group to an epoxy group in a bifunctional bisphenol A type epoxy resin.