JPH0150248B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an unsaturated polyester resin from at least an unsaturated dibasic acid or its anhydride and isophthalic acid as dibasic acid components and propylene oxide. .

Conventionally, unsaturated polyester resins containing isophthalic acid as part of the acid component have different resin properties, compared to unsaturated polyester resins containing orthophthalic acid.
That is, it is well known that it has excellent water resistance, chemical resistance, and mechanical properties. but,
When using isophthalic acid, the esterification reaction takes a longer time than when using orthophthalic acid, and the drawback is that the productivity is low.

Two types of methods, called a one-stage method and a two-stage method, are generally known as methods for producing isophthalic acid-based unsaturated polyester resins. That is, the one-stage method is a method in which all acid components including isophthalic acid and polyhydric alcohol components such as glycols are reacted simultaneously, and the two-stage method is a method in which isophthalic acid and polyhydric alcohol components such as glycols are reacted at the same time. This is a method in which the oligoester is reacted until it reaches a certain value, generally 30 or less, and then the resulting oligoester is reacted with an unsaturated acid. Although the one-stage method has a shorter reaction time than the two-stage method, it is known that the performance of the resulting resin is inferior [Reinforced Plastics, 19
Vol. 38 (1973)]. Since unsaturated polyester resins obtained by a one-stage process have poor water resistance, chemical resistance, and mechanical properties, high-performance isophthalic acid-based unsaturated polyester resins are usually produced by a two-stage process.

On the other hand, many proposals have already been made regarding methods for producing unsaturated polyester resins by reacting alkylene oxide with dicarboxylic acids or their anhydrides. However, this method is not known for unsaturated polyester resins in which isophthalic acid is used as one of the acid components. The reason is that isophthalic acid has an extremely high melting point and extremely low solubility in the reaction medium.
It has been said that this is because the reaction is difficult.

In addition, since adducts of aromatic dicarboxylic acids and alkylene oxides are easily produced, for example, in the presence of amine compound catalysts, they are used as intermediate raw materials for polyester resins, mainly saturated linear polyesters. well known. However, when such adducts are used as they are as intermediate raw materials for unsaturated polyester resins, the resulting resins are highly colored, lack stability in various properties related to curing behavior, and do not have sufficient storage stability. It has been said that practical inconveniences such as these are difficult to avoid.

The present inventors have conducted intensive studies to produce an unsaturated polyester resin in an economically advantageous manner using the above oligoester, which is an adduct of isophthalic acid and alkylene oxide, especially propylene oxide, as an intermediate raw material. I did this.

The present inventors first caused an addition reaction between isophthalic acid and propylene oxide in the presence of an amine compound catalyst, heat-treated the resulting reaction product,
A method was proposed in which an oligoester was then obtained by adsorption treatment, and an unsaturated polyester resin was produced using this as an intermediate (Japanese Patent Application No. 70450/1983), but the present invention is capable of producing isophthalic acid using a further simplified operation. The present invention provides a method for producing an unsaturated polyester resin.

That is, the present invention uses at least an unsaturated dibasic acid or its anhydride and isophthalic acid as the dibasic acid component, and in producing an unsaturated polyester resin from this and propylene oxide, the isophthalic acid and propylene oxide are combined in tetrahedron. The oligoester is obtained by reaction in the presence of an alkyl ammonium salt, the oligoester obtained by the reaction is heated to a temperature of 180°C to 280°C to distill off volatile components, and then heated. The oligoester obtained by
This is a method for producing an unsaturated polyester resin having excellent performance by reacting it with a dibasic acid component containing a basic acid or its anhydride.

Therefore, the object of the present invention is to provide a method for economically producing isophthalic acid-based unsaturated polyester resin having excellent water resistance, chemical resistance, mechanical properties, etc., in an extremely simplified process and in a short time. Our goal is to provide the following.

Hereinafter, the method of the present invention will be explained in detail based on specific embodiments. The method of the present invention consists of the following combined steps.

The first step of the present invention is to produce an oligoester by addition reaction of propylene oxide to isophthalic acid. Specifically, this step uses a reaction medium, charges isophthalic acid in the presence of a tetraalkylammonium salt catalyst, heats it to a predetermined temperature, and stirs it under normal pressure, if desired, under pressure. This is done by continuously injecting propylene oxide into the reactor. The molar ratio of propylene oxide to isophthalic acid is 1.1 to 3.3, preferably 1.2.
Selected in the range of ~3.0.

In this addition reaction, it is also possible to replace a part of isophthalic acid with another saturated dicarboxylic acid. Examples of these saturated dicarboxylic acids include phthalic acid, terephthalic acid, tetrahydrophthalic acid, 3,6-endomethylenetetrahydrophthalic acid, pimelic acid, adipic acid, glutaric acid, succinic acid, and sebacic acid. These saturated dicarboxylic acids may be substituted within 30 mol% of the amount of isophthalic acid used. Further, a part of propylene oxide can be replaced with other alkylene oxide. These alkylene oxides include ethylene oxide, butylene oxide, amylene oxide, hexane oxide, etc., and may be substituted within 30 mol% of the amount of propylene oxide used.

In the first step, a tetraalkylammonium salt is used as a catalyst, with the primary purpose of promoting the reaction between isophthalic acid and propylene oxide, and the secondary purpose of controlling the structure of the oligomer produced. Specifically, the tetraalkylammonium salts include tetramethylammonium chloride, tetramethylammonium bromide,
Tetramethylammonium iodide, tetramethylammonium hydroxide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, tetraethylammonium hydroxide, tetrapropylammonium chloride, tetrapropylammonium bromide, tetrapropylammonium hydroxide, tetrabutylammonium chloride , tetrabutylammonium bromide, tetramethylammonium bicarbonate, tetraethylammonium bicarbonate, tetramethylammonium carbonate, tetraethylammonium carbonate, tetramethylammonium benzoate, tetraethylammonium benzoate, bis(tetramethylammonium) phthalate, bis(tetraethylammonium) phthalate, "Bis(tetramethylammonium) isophthalate, bis(tetraethylammonium)
Isophthalate, bis(tetramethylammonium) terephthalate, bis(tetraethylammonium) terephthalate, bis(2-hydroxyethyltriethylammonium)isophthalate, bis(2-hydroxyethyltripropylammonium)isophthalate, mono(2-hydroxypropyltriethyl) Examples include ammonium) isophthalate, bis(tetraethylammonium) oxazole, and the like, and these may be used alone or in combination.

It is said that the addition reaction mainly proceeds in the form shown by the following general formula, (Here, n and m are 0, 1, 2, 3...
Indicates an integer indicated by . ) When a large amount of the catalyst tetraalkylammonium salt is used, the oligoester produced is (1)
Among the oligomers represented by the formula, the proportion of oligomers in which n and m are relatively small integers increases; in other words, the content of ether bonds in the molecular structure decreases. On the other hand, when the amount of catalyst is small, the number of ether bonds in the oligomer represented by formula (1) tends to increase.

In this way, being able to control the proportion of ether bonds contained in oligoesters by changing the amount of catalyst can control the performance of the resulting resin when producing unsaturated polyester resins using this oligoester as a raw material. It means to get. The advantage of being able to select any embodiment by adjusting the amount of catalyst in this way further enhances the significance of the present invention. Generally speaking, as the proportion of ether bonds present in oligoesters increases, the performance of cured unsaturated polyester resins made from oligoesters decreases in terms of elastic modulus and heat distortion temperature, while elongation rate decreases. increases, showing a tendency to be highly flexible.

Taking the above facts into consideration, in the method of the present invention, the amount of catalyst during oligoester production is selected from the range of 0.01 to 0.5% by weight based on isophthalic acid, depending on the desired performance of the unsaturated polyester resin. .

As the reaction catalyst, the oligoester itself obtained in this first step may be used, but in addition, oligomers obtained by esterifying isophthalic acid and propylene glycol, etc.
An oligoester having a similar structure or substantially the same structure as the oligoester produced in the first step may also be used.

The first step, oligoester production, is carried out under normal pressure.
It is carried out at a temperature of 100 to 230°C, preferably 110 to 220°C, optionally under pressure. In reactions under pressure, the pressure varies depending on conditions such as the injection rate of propylene oxide, the type and amount of the solvent used, the amount of catalyst, and the temperature, but it is usually selected within a pressure range of 15 kg/cm ² G or less. It will be done. The reaction time also varies depending on the above conditions, but is usually set between 10 and 240 minutes, preferably between 15 and 180 minutes.

The second step of the present invention is a step of heat-treating the reaction product containing the oligoester obtained in the first step at a high temperature. By this treatment, all volatile components including unreacted alkylene oxide and volatile substances generated by decomposition due to heating are distilled off. The compounds decomposed by this high-temperature heat treatment include the tetraalkylammonium salt used as a catalyst, and as a result, substantially no catalyst remains in the product obtained by the heat treatment.
Therefore, the oligoester obtained by heat treatment in the second step can be directly used for producing an unsaturated polyester resin without undergoing any purification operation.

The second step is operated under normal pressure, optionally under reduced pressure, and at a temperature of 180 to 280°C, preferably 220 to 270°C.

If the acid value of the oligoester obtained in the first step is not sufficiently lowered, the esterification reaction will proceed simultaneously during the high temperature treatment in this step, the generated water will also be removed, and the acid value will decrease rapidly. . This results in imparting more useful performance to the oligoester as an intermediate raw material for unsaturated polyester resin, and increases the significance of the high temperature treatment in the second step.

In the second step, when the reaction product containing the oligoester obtained in the first step is heat-treated at high temperature, it is one of the preferred embodiments to add isophthalic acid to the reaction product. In this case, the esterification reaction occurs simultaneously during the high temperature treatment,
The ratio of the isophthalic acid component and the propylene oxide component contained in the oligoester obtained after the heat treatment can be changed. That is,
Generally, the ratio of the isophthalic acid component and the propylene oxide component in the oligoester is controlled by the charging ratio of isophthalic acid and propylene oxide in the first step, but the component ratio can also be controlled by the above embodiment. This means that it is possible to meet the demand for the preparation of unsaturated polyester resins with a wider range of compositions, and to provide oligoesters with high practical value.

The third step of the present invention is to condense the oligoester obtained in the second step with an unsaturated dibasic acid or its anhydride, by further adding a saturated dibasic acid and/or a polyhydric alcohol as necessary. This is a manufacturing process for unsaturated polyester resin.

Examples of the unsaturated dibasic acid component used in the condensation reaction include maleic anhydride, maleic acid, fumaric acid, itaconic acid, citraconic acid, etc., and two or more types can be mixed and used as desired. I can do it. Examples of the saturated dibasic acid used in combination with the unsaturated dibasic acid component if necessary include phthalic acid, halogenated phthalic acid, phthalic anhydride,
Halogenated phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, 3,6
- Endomethylenetetrahydrophthalic acid, succinic acid, adipic acid, glutaric acid, pimelic acid, succinic acid, azelaic acid, sebacic acid, etc. In addition, polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol,
Examples include 3-butylene glycol, 1,6-hexanediol, neopentyl glycol, hydrogenated bisphenol A, and adducts of bisphenol A with ethylene oxide and propylene oxide.

In the third step, the intermediate product oligoester is subjected to a condensation reaction with an unsaturated dibasic acid, and if desired, a saturated dibasic acid and/or a polyhydric alcohol to produce an unsaturated polyester. The blending conditions for each reaction component are set within a range that satisfies the following formula.

1≦(c+d)/(a+b)≦1.2 where a: Number of moles of unsaturated dibasic acid component b: Number of moles of saturated dibasic acid component c: Number of moles of oligoester d: Number of moles of polyhydric alcohol The condensation reaction is carried out according to a conventional method, usually at a temperature in the range of 150 to 250°C, and under any pressure, such as increased pressure, normal pressure, or reduced pressure. The completion of the condensation reaction is
The reaction is determined by the acid value of the condensation product obtained, and the reaction is usually stopped when the acid value of the product reaches 50 or less, preferably 30 or less.

The temperature of the unsaturated polyester obtained by the condensation reaction is lowered to below 150°C according to a conventional method, and if necessary, a known polymerization inhibitor such as hydroquinone is added, and a vinyl monomer is added. , are mixed under stirring to form an unsaturated polyester resin. The vinyl monomer used here is one that is copolymerized with unsaturated polyester and acts as a crosslinking agent, such as vinylbenzenes such as styrene, halogenated styrene, α-methylstyrene, vinyltoluene, and divinylbenzene. ; Methyl methacrylate,
These include (meth)acrylic acid esters such as methyl acrylate and ethylene glycol dimethacrylate; and polyvalent allyl compounds such as diallyl phthalate and triallyl cyanurate. The polymerization inhibitor added as necessary when mixing vinyl monomers is selected from known polymerization inhibitors such as p-tert-butylcatechol, hydroquinone, toluhydroquinone, benzoquinone, and copper naphthenate. selected. The amount added is 30 to 500 ppm to unsaturated polyester resin.
selected at a ratio of

As described in detail above, the present invention is a method for producing isophthalic acid-based unsaturated polyester resin with excellent various properties in a short time through simplified steps. do.

Comparative example Production of oligoester 1661 g of isophthalic acid and 1522 g of propylene glycol were charged into a reactor equipped with a stirrer, partial reflux device, thermometer and nitrogen gas inlet tube, and heated to 205°C while flowing nitrogen gas at a rate of 400 ml/min. The temperature rose. Steam at 100°C was passed through a partial reflux vessel, and water produced by condensation was distilled off while propylene glycol was refluxed. After about 10 hours, 2810 g of a reaction product (oligoester A) having an acid value of 10, a Gardner color number of 2, and a viscosity of 3500 poise (at 25° C.) was obtained.

Production of unsaturated polyester resin 2525 g of oligoester A, 883 g of maleic anhydride, and 150 g of propylene glycol were charged into a reactor equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a partial reflux device with a thermometer attached to the top of the column. 400
The temperature was raised to 220° C. while flowing nitrogen gas at ml/min. Propylene glycol was refluxed while flowing steam at 100°C through the partial reflux vessel, and condensed water was distilled out of the system. When the acid value reaches 20, remove the partial reflux device and reduce the nitrogen gas flow rate to 1000ml/
As the reaction progressed for several minutes, unreacted glycol remaining in the system was removed. 13 hours after the start of the reaction, acid value 10, Gardner color number 2, Gardner viscosity ×
(Color number and viscosity measured as a 40% styrene solution)
3400g of unsaturated polyester was obtained. After the reaction was completed, the internal temperature was lowered to 180 to 190°C, and 0.05 part of a polymerization inhibitor (hydroquinone) was added, and then dissolved in styrene monomer to obtain a liquid unsaturated polyester resin.

Example 1 Production of oligoester 1882 g of oligoester A obtained in Comparative Example, 1661 g of isophthalic acid and 13.9 g of tetraethylammonium chloride were added to a reactor equipped with a stirrer, a thermometer, a nitrogen inlet pipe and a thermometer attached to the top of the column. The mixture was charged into a reactor, the inside of the reactor was sufficiently purged with nitrogen gas, and the temperature was raised to 160°C. When the internal temperature reaches 160℃, increase the stirring speed to 500rpm and add 1162g of propylene oxide while keeping the temperature constant.
was continuously injected into the reactor over a period of 130 minutes.
During propylene oxide injection, cold water was circulated through the reflux vessel, and the entire amount of unreacted propylene oxide was refluxed. After propylene oxide injection,
The reaction was continued for an additional 10 min at 160°C until the acid number reached 35.
(mgKOH/g) of the reaction product was obtained.

Then, the temperature was raised to 250° C. while continuously flowing nitrogen gas at a rate of 400 ml/min. 100℃ for the reflux vessel
Steam was passed through the tank to sufficiently distill off the volatile substances together with the condensed water. After 30 minutes, the product was cooled to 100°C and added to propylene glycol with continued stirring.
248 g was added to obtain 4785 g of oligoester (oligoester B) having an acid value of 2.0, a Gardner color number of 1, and a residual catalyst of 1.8 ppm (in terms of nitrogen).

Production of unsaturated polyester resin A reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet pipe, and a partial refluxer with a thermometer attached to the top of the column.
Prepare 1467g of oligoester B, 76g of propylene glycol, and 491g of maleic anhydride.
The condensation reaction was carried out by raising the temperature to 210° C. while flowing nitrogen gas at 300 ml/min. 100℃ for partial reflux
of steam was flowed to reflux the propylene glycol, and the water of condensation was distilled off. When the acid value reaches 20, remove the partial reflux device and reduce the nitrogen gas flow rate to 1200.
ml/min, and condensed water and unreacted glycol were removed from the system. 13 hours after the start of the reaction, acid value 9.8,
Gardner viscosity X, Gardner color number 2-3 (Viscosity and color number were measured as a 40% styrene solution.)
1905g of unsaturated polyester was obtained.

0.2 g of hydroquinone was added to the obtained unsaturated polyester, and 1270 g of styrene was further added and mixed to obtain a liquid unsaturated polyester resin with a styrene content of 40%. This liquid resin could be stably stored at 40°C for more than 3 months, exhibited excellent color tone and curing performance, and had good physical properties of the cured resin.

Example 2 Production of oligoester 1882g of oligoester A obtained in the comparative example, 1661g of isophthalic acid, and 9.71g of tetramethylammonium chloride were placed in a stainless steel autoclave, the inside of the reactor was sufficiently purged with nitrogen gas, and the temperature was raised to 210°C. did. When the internal temperature reached 210°C, the stirring speed was set to 50 rpm, and 1162 g of propylene oxide was continuously press-ined over 40 minutes while keeping the temperature constant. After the propylene oxide injection was completed, the reaction was continued for an additional 10 minutes at 210°C. The pressure during the reaction reached a maximum of 2.1Kg/cm ² . Acid value 35 (mg
4620 g of reaction product (KOH/g) was obtained.

2833g of this reaction product was transferred to a reactor equipped with a stirrer, a partial refluxer, and a nitrogen gas inlet tube, and nitrogen gas was continuously flowed at 400ml/min. At the same time, while steam at 100°C was flowing through the partial refluxer, the reaction was carried out. The temperature inside the vessel was raised to 250°C, and volatile substances were sufficiently distilled off together with condensed water. After 30 minutes, the product was heated to 100℃
153 g of propylene glycol was added with continued stirring to obtain 2986 g of an oligoester (Oligoester C) having an acid value of 2.0, a Gardner color number of 1, and a residual catalyst of 19 ppm (in terms of nitrogen).

Production of unsaturated polyester resin 735 g of oligoester C and propylene glycol were placed in a reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, and a partial reflux vessel with a thermometer attached to the top of the column.
Prepared 457g and fumaric acid 871g, 300g
The condensation reaction was carried out by raising the temperature to 210° C. while flowing nitrogen gas at ml/min. Steam at 100°C was passed through the partial reflux vessel to reflux propylene glycol and distill water of condensation. When the acid value reached 40, remove the partial reflux device and reduce the nitrogen gas flow rate to 1200.
ml/min, and condensed water and unreacted glycol were removed from the system. 8.5 hours after the start of the reaction, the acid value
33.0, Gardner viscosity K and Gardner color number
1760 g of unsaturated polyester having a viscosity of 2 to 3 (viscosity and color number measured as a 40% styrene solution) was obtained.

0.2 g of toluhydroquinone was added to the obtained unsaturated polyester, and 1173 g of styrene was further added and mixed to obtain a liquid unsaturated polyester resin with a styrene content of 40%.

Example 3 Production of oligoester 1727 g of oligoester B obtained in Example 1, 1661 g of isophthalic acid, and 9.71 g of tetraethylammonium bromide were added to a reactor equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a reflux vessel with a thermometer attached to the top of the column. The mixture was charged into a reactor, the inside of the reactor was sufficiently purged with nitrogen gas, and the temperature was raised to 170°C. When the internal temperature reaches 170℃, increase the stirring speed to 500rpm and add 930g of propylene oxide while keeping the temperature constant.
was continuously injected into the reactor over a period of 120 minutes.
During propylene oxide injection, cold water was circulated through the reflux vessel, and the entire amount of unreacted propylene oxide was refluxed. After propylene oxide injection,
The reaction was further continued at 160℃ and the acid value was 44 (mg
4241 g of a reaction product of KOH/g) was obtained.

2,689 g of this reaction product was transferred to a reactor equipped with a stirrer, a partial reflux device, and a nitrogen gas inlet tube, and nitrogen gas was continuously flowed at a rate of 400 ml/min. Then, the temperature inside the reactor was raised to 250°C, and volatile substances were distilled off together with condensed water. After 30 minutes, the product was cooled and the oligoester obtained was a viscous liquid with an acid value of 3.0 and a residual catalyst of 17 ppm (nitrogen equivalent). This oligoester is referred to as oligoester D.

Production of unsaturated polyester resin A reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet pipe, and a partial refluxer with a thermometer attached to the top of the column.
Oligoester D 1568g, maleic anhydride
Prepared 392g and 106g of propylene glycol,
The condensation reaction was carried out by raising the temperature to 210° C. while flowing nitrogen gas at 300 ml/min. 100℃ for partial reflux
Steam was supplied to reflux propylene glycol, and water of condensation was distilled off. When the acid value reaches 25, remove the partial reflux device and reduce the nitrogen gas flow rate to 1200.
Condensed water and unreacted glycol were removed from the system at a rate of ml/min. 6 hours after the start of the reaction, acid value 18.0,
An unsaturated polyester having a Gardner viscosity of E and a Gardner color number of 2 (viscosity and color number were measured as a 40% styrene solution) was obtained.

A polymerization inhibitor hydroquinone was added to the obtained unsaturated polyester, and styrene was further added and mixed to obtain a liquid unsaturated polyester resin.

Example 4 Production of oligoester 1727 g of oligoester B obtained in Example 1, 1661 g of isophthalic acid, and 10.47 g of tetrapropylammonium bromide were placed in a stainless steel autoclave, the inside of the reactor was sufficiently purged with nitrogen gas, and the temperature was raised to 210°C. It was warm. When the internal temperature reached 210℃, the stirring speed was set to 500rpm, and while keeping the temperature constant, 930g of propylene oxide was added to 40g of propylene oxide.
It was continuously press-fitted in minutes. After the propylene oxide injection was completed, the reaction was continued at 210°C for an additional 10 minutes.
The pressure during the reaction is a maximum of 2.1 (mgKOH/g), resulting in a viscous liquid.

2683g of this reaction product was charged into a reactor equipped with a stirrer, partial reflux device and nitrogen inlet tube, and nitrogen gas was introduced into the reactor.
The temperature inside the reactor was raised to 250°C while flowing the water continuously at 400ml/min, and at the same time flowing steam at 100°C through the partial reflux vessel to distill off volatile substances together with condensed water. After 30 minutes, the product obtained by cooling was a viscous liquid oligoester (oligoester E) with an acid value of 2.6 and a residual catalyst amount of 18 ppm (in terms of nitrogen).

Production of unsaturated polyester resin 1042 g of oligoester E and propylene glycol were placed in a reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, and a partial reflux vessel with a thermometer attached to the top of the column.
83 g of dipropylene glycol, 403 g of dipropylene glycol, and 589 g of maleic anhydride were charged, and the temperature was raised to 230° C. while flowing nitrogen gas at 300 ml/min to carry out a condensation reaction. Flow 100℃ steam into the partial reflux vessel.
Glycols were refluxed and water of condensation was distilled off.
When the acid value reached 30, the partial reflux device was removed, the nitrogen gas flow rate was increased to 1200 ml/min, and condensed water and unreacted glycol were removed from the system. Ten hours after the start of the reaction, an unsaturated polyester having an acid value of 25.5, a Gardner viscosity of O to P, and a Gardner color number of 3 (viscosity and color number were measured as a 40% styrene solution) was obtained. This was mixed with a polymerization inhibitor and styrene to obtain a liquid unsaturated polyester resin.

Example 5 Production of oligoester 1882 g of oligoester B obtained in Example 1, 1661 g of isophthalic acid, and 11.18 g of tetrapropylammonium chloride were prepared using a stirrer, a thermometer, a nitrogen inlet tube, and a reflux device equipped with a thermometer at the top of the column. The mixture was charged into a reactor, the inside of the reactor was sufficiently purged with nitrogen gas, and the temperature was raised to 160°C. When the internal temperature reaches 160℃, increase the stirring speed to 500rpm and add 1162g of propylene oxide while keeping the temperature constant.
was continuously injected into the reactor over a period of 125 minutes.
During propylene oxide injection, cold water was circulated through the reflux vessel, and unreacted propylene oxide was refluxed. After propylene oxide injection, 160℃
The reaction was continued for an additional 10 minutes. Acid value 33 (mg
4622 g of reaction product (KOH/g) was obtained.

2834g of this reaction product and 1107g of isophthalic acid
was transferred to a reactor equipped with a stirrer, partial refluxer, and nitrogen introduction, and nitrogen gas was continuously flowed at 400 ml/min. At the same time, while 100°C steam was flowing into the partial refluxer, the temperature inside the reactor was raised to 250°C. The temperature was raised. Approximately 120
The reaction was continued for a minute, and the water of condensation and volatile substances were sufficiently distilled off. As a result, the softening point is approximately 75℃, the acid value
12.4 Solid product oligoester F at room temperature
Obtained 3548g.

Production of unsaturated polyester resin 1630 g of oligoester F, 245 g of maleic anhydride, and 235 g of propylene glycol were charged into a reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, and a reflux device with a thermometer attached to the top of the tower, and 300 ml was charged. The condensation reaction was carried out by raising the temperature to 220° C. while flowing nitrogen gas for 1 minute. Steam at 100°C was passed through the partial reflux vessel to reflux propylene glycol and distill water of condensation. When the acid value reached 30, the partial reflux device was removed, the nitrogen gas flow rate was increased to 1200 ml/min, and condensed water and unreacted glycol were removed from the system. Seven hours after the start of the reaction, an unsaturated polyester having an acid value of 16.0, a Gardner viscosity G and a Gardner color number of 2 (viscosity and color number were measured as a 40% styrene solution) was obtained.

A polymerization inhibitor was added to the obtained unsaturated polyester, and styrene was further added and mixed to obtain a liquid unsaturated polyester resin.

Example 6 Production of oligoester Oligoester B 1882- obtained in Example 1, 1661 g of isophthalic acid, and 10.14 g of tetramethylammonium iodide were mixed in a stirrer, a thermometer, a nitrogen inlet pipe, and a reflux vessel equipped with a thermometer at the top of the column. The reactor was charged into a reactor equipped with nitrogen gas, the inside of the reactor was sufficiently purged with nitrogen gas, and the temperature was raised to 180°C. When the internal temperature reaches 180℃, increase the stirring speed to 500rpm and add 1162g of propylene oxide while keeping the temperature constant.
was continuously injected into the reactor over 130 minutes. During propylene oxide injection, cold water was circulated through the reflux vessel, and unreacted propylene oxide was refluxed.
After the propylene oxide injection was completed, the reaction was continued at 180°C for another 10 minutes until the acid value reached 37 (mgKOH/
4620 g of the reaction product g) was obtained.

2833g of this reaction product and 1107g of isophthalic acid
was transferred to a reactor equipped with a stirrer, a partial reflux device, and a nitrogen inlet tube, and nitrogen gas was continuously flowed at a rate of 400 ml/min.
At the same time, the temperature inside the reactor was raised to 240°C while flowing 100°C steam into the partial reflux vessel. about
The reaction was continued for 130 minutes, and the condensed water and volatile substances were sufficiently distilled off. A solid product (oligoester G) having a softening point of about 76° C. at room temperature was obtained.

Production of unsaturated polyester resin 542 g of oligoester G, 871 g of fumaric acid, 729 g of neopentyl glycol, and propylene glycol were placed in a reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet pipe, and a reflux device with a thermometer at the top of the column.
A condensation reaction was carried out by raising the temperature to 210° C. while flowing nitrogen gas at 300 ml/min. Steam at 100°C was passed through the partial reflux vessel to reflux the glycols and distill off the condensed water. Start of reaction
After 17 hours, acid value 28.4, Gardner viscosity U and Gardner color number 2-3 (viscosity and color number are styrene
An unsaturated polyester (measured as a 40% solution) was obtained.

A polymerization inhibitor and styrene were added to and mixed with the obtained unsaturated polyester to obtain an unsaturated polyester resin.

Example 7 Production of oligoester 1727g of oligoester A obtained in Reference Example, 1661g of isophthalic acid, and 12.7g of bis(tetramethylammonium)isophthalate were mixed with a stirrer, a thermometer, a nitrogen inlet tube, and a thermometer attached to the top of the column. The mixture was charged into a reactor equipped with a reflux device, the inside of the reactor was sufficiently purged with nitrogen gas, and the temperature was raised to 170°C. Internal temperature
When the temperature reached 170℃, the stirring speed was increased to 500rpm.
While keeping the temperature constant, 1162 g of propylene oxide was continuously injected into the reactor over a period of 120 minutes. During propylene oxide injection, cold water was circulated through the reflux vessel, and the entire amount of unreacted propylene oxide was refluxed. After the propylene oxide injection was completed, the reaction was continued at 165°C for an additional 15 minutes.
4480 g of a reaction product with an acid value of 37 (mgKOH/g) was obtained.

2800 g of this reaction product was transferred to a reactor equipped with a stirrer, a partial reflux device, and a nitrogen gas inlet tube, and nitrogen gas was continuously flowed at a rate of 400 ml/min. The temperature inside the reactor was raised to 250°C, and volatile substances were distilled off together with condensed water. After 30 minutes, the product was cooled and the oligoester obtained was a viscous liquid with an acid value of 2.5 and a residual catalyst of 15 ppm (nitrogen equivalent).

This oligoester is referred to as oligoester H.

Production of unsaturated polyester resin A reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet pipe, and a partial refluxer with a thermometer attached to the top of the column.
Oligoester H 1662g, maleic anhydride
392 g and 15 g of propylene glycol were charged, and the temperature was raised to 210° C. while flowing nitrogen gas at 300 ml/min to perform a condensation reaction. In the partial reflux device
Steam at 100°C was passed to reflux propylene glycol, and water of condensation was distilled off. When the acid value reached 25, the partial reflux device was removed, and the nitrogen gas flow rate was increased to 1200 ml/min to remove condensed water and unreacted glycol from the system. 6 hours after the start of the reaction, the acid value
20, Gardner viscosity D to E, Gardner color number 2 (viscosity and color number are measured as a 45% styrene solution)
An unsaturated polyester was obtained.

A polymerization inhibitor hydroquinone was added to the obtained unsaturated polyester, and styrene was further added and mixed to obtain a liquid unsaturated polyester resin.

Example 8 Production of oligoester 1727 g of oligoester A obtained in Reference Example, 1661 g of isophthalic acid, and 11.0 g of tetramethylammonium bicarbonate were heated using a stirrer, a thermometer, a nitrogen inlet tube, and a reflux vessel equipped with a thermometer at the top of the column. The mixture was charged into a reactor equipped with the reactor, the inside of the reactor was sufficiently purged with nitrogen gas, and the temperature was raised to 170°C. When the internal temperature reaches 170°C, increase the stirring speed to 500 rpm and add propylene oxide while keeping the temperature constant.
1162 g was continuously injected into the reactor over a period of 120 minutes. During propylene oxide injection, cold water was circulated through the reflux vessel, and the entire amount of unreacted propylene oxide was refluxed. After the propylene oxide injection was completed, the reaction was continued at 165°C for an additional 15 minutes, and the acid value was
4485 g of a reaction product of 38 (mgKOH/g) was obtained.

2800 g of this reaction product was transferred to a reactor equipped with a stirrer, a partial reflux device, and a nitrogen gas inlet tube, and nitrogen gas was continuously flowed at a rate of 400 ml/min. The temperature inside the reactor was raised to 250°C, and volatile substances were distilled off together with condensed water. After 30 minutes, the product was cooled and the oligoester obtained was a viscous liquid with an acid value of 2.8 and a residual catalyst of 18 ppm (nitrogen equivalent).

This oligoester is referred to as oligoester I.

Production of unsaturated polyester resin A reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet pipe, and a partial refluxer with a thermometer attached to the top of the column.
Oligoester I 1662g, maleic anhydride
392 g and 15 g of propylene glycol were charged, and the temperature was raised to 210° C. while flowing nitrogen gas at 300 ml/min to perform a condensation reaction. In the partial reflux device
Steam at 100°C was passed to reflux propylene glycol, and water of condensation was distilled off. When the acid value reached 25, the partial reflux device was removed, and the nitrogen gas flow rate was increased to 120 ml/min to remove condensed water and unreacted glycol from the system. 6 hours after the start of the reaction, the acid value
17, Gardner viscosity D to E, Gardner color number 3 (viscosity and color number are measured as a 45% styrene solution)
An unsaturated polyester was obtained.

A polymerization inhibitor hydroquinone was added to the obtained unsaturated polyester, and styrene was further added and mixed to obtain a liquid unsaturated polyester resin.

Claims (1)

[Claims] 1. Using at least an unsaturated dibasic acid or its anhydride and isophthalic acid as the dibasic acid component,
In producing an unsaturated polyester resin from this and propylene oxide, (1) Isophthalic acid 1 is reacted with oligoester obtained by reacting isophthalic acid with propylene oxide or propylene glycol in the presence of a tetraalkylammonium salt catalyst as a reaction medium. an addition reaction step in which moles are reacted with 1.1 to 3.0 moles of propylene oxide; (2) heating in which the reaction product containing the oligoester obtained in the addition reaction step is heated to a temperature of 180 to 280°C to distill off volatile components; The oligoester obtained in the treatment step and (3) the heat treatment step is subjected to a condensation reaction with a dibasic acid component containing at least an unsaturated dibasic acid or its anhydride to produce an unsaturated polyester, and the resulting unsaturated polyester is A method for producing an isophthalic acid-based unsaturated polyester resin, which includes a resin conversion step of adding a polymerization inhibitor and a vinyl monomer to a saturated polyester to obtain a liquid unsaturated polyester resin.