JPS6019771B2 - Method for producing unsaturated polyester resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an unsaturated polyester resin consisting of an unsaturated polyester containing dicarboxylic acid anhydride and alkylene oxide as main components and a polymerizable unsaturated monomer. It is.

Conventionally, there has been a method for producing unsaturated polyester from dicarboxylic anhydride and alkylene oxide (hereinafter simply referred to as the oxide method).

), and it is well known that some of them have already been put into practical use industrially. This oxide method is compared to other condensation methods that produce unsaturated polyesters from dicarboxylic acids and/or their anhydrides and polyhydric alcohols through dehydration condensation reactions.
It was introduced with the following advantages 1 and 2 as its biggest features. However, it has many disadvantages compared to the condensation method, and the following disadvantages 1 to 4 can be cited as representative examples. Advantage 1: Short reaction time.

Advantage 2: Product yield is high because it is an addition polymerization reaction.

Defect 1: The resulting unsaturated polyester is significantly colored.
Disadvantage 2: The copolymerization reactivity between the obtained unsaturated polyester and the polymerizable unsaturated monomer is low. Disadvantage 3: Since the main raw materials are limited to dicarboxylic acid anhydride and alkylene oxide, the degree of freedom in molecular design of unsaturated polyester from the viewpoint of raw materials is low.

Disadvantage 4: Side reactions tend to occur in the late stage of the reaction, resulting in the unsaturated polyester having a strange odor and poor storage stability when mixed with a polymerizable unsaturated monomer to form an unsaturated polyester resin. .

Furthermore, the deterioration in storage stability in this case is difficult to improve even if the unsaturated polyester is stripped with an inert gas to remove the off-odor.

Several methods have been proposed to compensate for these shortcomings.

For example, as a method for compensating for drawback 2, a method has been proposed in which unsaturated polyester derived by the oxide method is heat treated. Although it is true that this method improves the copolymerization reactivity of the unsaturated polyester obtained with the polymerizable unsaturated monomer, the molecular weight of the unsaturated polyester is sufficiently large to be practically acceptable (for example, 1000 In the above cases, an extremely long heat treatment is required, which reduces one of the greatest advantages of the oxide method, Advantage 1, and makes the oxide method extremely unattractive. A special method proposed to improve defect 2 is the method disclosed in Japanese Patent Publication No. 39-684y.

Although defect 2 is certainly improved to a large degree by following this method, defect 1 is still unresolved, and in order to obtain an unsaturated polyester with a commercially acceptable acid value, heat treatment is required. It is stated that it is preferable to further introduce alkylene oxide later to lower the acid value, which is not necessarily a satisfactory method. This is because the alkylene oxide added to achieve a commercially acceptable degree of oxidation in this process has a greater chance of reacting with the terminal hydroxyl groups of the unsaturated polyester to form ether groups, resulting in This is because a long inert end portion is introduced into the resin, which deteriorates the physical properties of the resulting unsaturated polyester resin and its cured product. Tsubaki Kaisho 51-6 as another method to improve the drawbacks of the oxide method
The method shown in US Pat. No. 5,198 is also known.

If this method is followed, Defect 2 will certainly be improved and Defect 1 will also be improved to a considerable extent, but it is not suitable for applications where appearance is extremely important, such as gold 0, molded products, paints, decorative laminates, etc. Only unsaturated polyester resins of unsatisfactory hue can be provided. In addition, since this method uses a large amount of glycol, the amount of water removed in the condensation step is large, which reduces the second advantage of the oxide method. As mentioned above, although the oxide method is economically superior to the condensation method, its usage is extremely low compared to the condensation method due to the lack of effective means to improve its drawbacks. is the current situation. The present inventors believe that if the above-mentioned disadvantages of the oxide method can be overcome, the industrial utility value of the oxide method can be greatly increased.As a result of intensive research, the inventors found that a specific raw material composition that is inseparable The present inventors have discovered that an excellent unsaturated polyester can be obtained by combining the process with specific conditions, and have completed the present invention.

Therefore, an object of the present invention is to provide a method for producing an unsaturated polyester resin based on the oxide method, which is capable of producing an excellent cured product with little coloration and excellent curing properties.

Other purposes will become apparent from the description below.
The method for producing an unsaturated polyester resin of the present invention is to produce an unsaturated polyester resin consisting of an unsaturated polyester (1) and a polymerizable unsaturated monomer (b). The following steps '1}, ■ and '3}
It is characterized by being obtained through. Process m:Q・
8-Unsaturated dicarboxylic anhydride [a' containing at least 20 mol % of dicarboxylic anhydride and 0.25 mol or more per mol of the dicarboxylic anhydride and 0.40
A carboxyl compound having a concentration of 0.33 to 0.65 equivalents/100 units is reacted with a dihydric alcohol in an amount in a ratio in the submolar range in an inert gas atmosphere, without catalyst, within a temperature range of 90 to 15,000 °C. A step of obtaining a reaction product mixture 'a) containing a group. Step ■: Reaction mixture {desktop alkylene oxide [C'] in an inert gas atmosphere, without catalyst, 110-1
The acid value is 70-160 when reacted within a temperature range of 90qo.
A step of obtaining a reaction product mixture 'Rho' having a difference between oxidation and hydroxyl values of 30 or less and a molecular weight of 400 to 800.

Step '3': The reaction product mixture [o} is heated in an inert gas atmosphere within a temperature range of 180 to 24,000 to an acid value of 15 to 6.
A step of obtaining an unsaturated polyester by dehydration condensation until the polyester is within the range of 0.

The present invention is characterized by necessarily passing through steps {2) and '3}, and only by doing so can the object of the present invention be achieved.

The dicarboxylic acid anhydride used in the present invention is Q
Contains at least 20 mol% of 8-unsaturated dicarboxylic anhydride a}. Examples of Q.8 monounsaturated dicarboxylic anhydride [a-] include maleic anhydride, itaconic anhydride, citracosic anhydride, etc., of which maleic anhydride is the most common. Examples of dicarboxylic anhydrides other than Q.8 monounsaturated dicarboxylic anhydride [a} include phthalic anhydride, tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, 3.6-ethyl anhydride, Anhydrides represented by ndomethylenetetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3,6-endodichloromethylenetetrachlorophthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, glutaric anhydride, or pentadodecylsuccinic anhydride. Examples include succinic acid substituted products. In the present invention, it is necessary that at least 20 mol % of the dicarboxylic anhydride is occupied by one or more of Q.8 monounsaturated dicarboxylic anhydrides {a-.

If the proportion of the Q.8-unsaturated dicarboxylic acid anhydride {a) is less than 20 mol %, the physical properties of the cured product of the unsaturated polyester resin derived therefrom will deteriorate, which is not preferable.
Examples of dihydric alcohol 'B' include ethylene glycol, diethylene glycol, and polyhydric alcohol.

Examples include polyethylene glycols such as pyrene glycol, dipropylene glycol, hexylene glycol, hydrogenated bisphenol A, neobentyl glycol, butylene glycol, or triethylene glycol, and polypropylene glycols such as tripropylene glycol. In particular, when ethylene glycol, diethylene glycol, propylene glycol, or dipropylene glycol is used as the main component, the unsaturated polyester resin produced according to the method of the present invention is the unsaturated polyester resin produced by the condensation method using a similar composition. Compared to resins, it is preferable because it has particularly excellent physical properties when made into a cured product. Moreover, the unsaturated polyester resin produced according to the method of the present invention, which contains 1,3-butylene glycol as a main component among butylene glycols, has higher performance compared to the unsaturated polyester resin produced by the condensation method using a similar composition. It is preferable because it is particularly excellent in hue and storage stability. Incidentally, instead of a portion of the dihydric alcohol, a monohydric alcohol such as methanol or octyl alcohol, or a trihydric or higher alcohol such as trimethylolpropane or bentaerythritol can be used as a denaturing agent.

The amount used is usually within 30 mol% of the dihydric alcohol (B); if it exceeds this range, the reaction in step '3' will not proceed smoothly with the monohydric alcohol, and the trihydric alcohol will not proceed smoothly. Gelation tends to occur with the above alcohols.The usage ratio of dicarboxylic anhydride ■ and dihydric alcohol 'B} is 0.25 mol or more of dihydric alcohol [B} per 1 mol of dicarboxylic anhydride style. , and less than 0.40 mol.

If the usage ratio of dihydric alcohol [B} is less than 0.25 mol, the reaction will proceed smoothly in the absence of a catalyst and may become thick, and the unsaturated polyester derived from it may exhibit a strange odor or change in color. Inconveniences such as deterioration are more likely to occur.

In addition, the ratio of dihydric alcohol (B) residues in the derived unsaturated polyester is small, making it difficult to introduce properties based on dihydric alcohol bending into unsaturated polyester. The degree of freedom in molecular design will be greatly reduced, and the degree of improvement of the above-mentioned disadvantage 3 will be reduced, which is undesirable.In addition, if it exceeds 0.40 mol, the above-mentioned advantages 1 and 2 will likely be lost. Unexpectedly, when the amount is 0.40 mol or more, it is also undesirable that the resin liquid properties and cured product physical properties of the unsaturated polyester resin derived therefrom deteriorate.In the present invention, Before introducing the alkylene oxide 'C', the dicarboxylic acid anhydride and the dihydric alcohol 'B' are reacted in advance in an inert gas atmosphere without a catalyst within a temperature range of 90 to 150 qo. , 0.33 to 0.65 equivalent/1
The process of obtaining a reaction product mixture containing carboxyl groups at a concentration of 0.00 ml is one of the essential requirements.
If alkylene oxide (alkylene oxide) is directly introduced into the mixture of dicarboxylic acid anhydride ■ and dihydric alcohol 'B} without going through this process {1}, the resulting unsaturated polyester will be colored. This makes it impossible to obtain an unsaturated polyester resin with a good hue that can be used in the purpose of the present invention, in which appearance is extremely important. The reason is Kou Kaede 1
This is thought to be because if the reaction is not carried out, the concentration of carboxyl groups in the reaction system is low, making it difficult for the reaction between the alkylene oxide and the carboxyl groups to occur, making side reactions more likely to occur.
In addition, the process (1 female inert gas atmosphere, no catalyst, 90-1
It is essential to carry out the reaction within a temperature range of 50 CO.

If this is not the case, the hue of the unsaturated polyester obtained will deteriorate, which is not preferable. Note that the inert gas referred to herein refers to a gas that does not react with components in the reaction system under the reaction conditions for producing unsaturated polyester, and nitrogen gas or carbon dioxide gas is generally used. If the reaction temperature in step {1) is lower than 9,000 ℃, it is not preferable because a long time is required to obtain the reaction product mixture (i).

Also, if it is higher than 150q○, side reactions are likely to occur,
I still don't like it. The reaction product mixture {i} obtained in step {1} of the present invention has an amount of 0.33 to 0.65 equivalent/10
It has a carboxyl group concentration of 0.

If the carboxyl group concentration is less than 0.33 equivalent/100 ta, it is not preferable because the hue of the unsaturated polyester obtained becomes poor. In addition, if the concentration is higher than 0.65 equivalents/100 equivalents, the molecular weight of the reaction product mixture obtained in the next step (2) will be lower, resulting in an unsaturated product with a commercially acceptable molecular weight. In order to obtain polyester, a long time is required in the subsequent step '31, and the amount of water removed is large. Therefore, the advantages 1 and 2 mentioned above are lost, which is not preferable. The carpoxyl group concentration of the reaction product mixture [I] was measured by John Mitchell (Jo
Chopsticks Organic Analysis (0rscalenlcikeal$is) Volume 3, page 104 (Interscience Publishers, Inc.
encePlishe Dai, Inc. , New York
) 195 Mother Sheep Publishing).

That is, the number x of moles of sodium methylate required to neutralize the reaction product mixture t'1 in a non-aqueous system using a sodium methylate solution, and the number of moles x of sodium methylate required to neutralize the reaction product mixture After converting the dicarboxylic anhydride group into a carboxyl group, it is calculated from the number of moles of sodium hydroxide, y, required for neutralization with an aqueous sodium hydroxide solution, using the formula (common y) x 100. Step '1) is generally carried out in a time of 60 minutes or less, and 10 to 20 minutes is usually sufficient. The alkylene oxide used in step [2] of the present invention refers to a compound having one atomic group shown in 1 molecule, such as ethylene oxide, propylene oxide, styrene oxide, epichlorohydrin, or allylglycidyl. Examples include ether and glycidyl compounds represented by benzoic acid glycidyl ether.

Among these, ethylene oxide and propylene oxide are most suitable. In step ■, the reaction product mixture
and alkylene oxide) in an inert gas atmosphere without a catalyst.
It should be carried out in the temperature range of 0:00. If the reaction is not carried out in an inert gas atmosphere without a catalyst, the resulting unsaturated polyester will have a poor hue, which is undesirable. Regarding the reaction temperature, if it is lower than 110°C, the reaction progresses slowly and is not preferable. On the other hand, if the temperature is higher than 190°C, the hue of the unsaturated polyester obtained will deteriorate,
I still don't like it. In step (2), the reaction is carried out at normal pressure or under a slightly increased pressure, and even when the pressure is increased, a pressure of 5k9/m or less is suitable.

This pressure does not affect the effects of the present invention.
The ratio of the reaction product mixture {A and alkylene oxide} in step [2} is the reaction product mixture {A and alkylene oxide}.
If the amount of dicarboxylic anhydride used to obtain is a mole, the amount of dihydric alcohol is b mole, and the amount of alkylene oxide {q is c mole, then (b+c)/a=0
．． A ratio of 9 to 2.0 is preferable.

However, it is not particularly limited to this value, and the acid value of the reaction product mixture [o} is within the range of 70 to 160,
The difference between acid value and hydroxyl value is 30 or less, and the molecular weight is 400.
Any value in the range of ~800 is sufficient. When the acid value of the reaction product mixture (o) is less than 7, side reactions are likely to occur, causing the resulting unsaturated polyester resin to exhibit an off-odor or deterioration in storage stability.

On the other hand, if the acid value exceeds 160, the acid value of the unsaturated polyester ultimately obtained will be too high, which is also undesirable. If the difference between the acid value and the hydroxyl value exceeds 30, the next step {3' will require a long time, which is not preferable. The molecular weight of the reaction product mixture 'rho is 4.
If the temperature is less than 0 degrees Celsius, the amount of dehydration in the process increases and the time required for the reaction becomes longer, which impairs the advantages 1 and 2. On the other hand, if the molecular weight exceeds 800, it will take a long time to improve the reactivity of the resin during dehydration condensation in the process leg, which is also undesirable.
The reaction product mixture obtained in Step (1) may be used directly in Step (3), or may be stored in a container and then used again in Step (3).

Step {Mechanically, the reaction product mixture obtained in Step 2} is subjected to dehydration condensation in an inert gas atmosphere at a temperature range of 180 to 240 qo until the acid value reaches a range of 15 to 60, thereby producing an unsaturated polyester. It's something you get. Process '3
}At a low temperature of less than 180 o'clock, it takes a long time for dehydration and condensation, and on the other hand, at a high temperature of more than 240 o'clock, coloration tends to occur due to side reactions, and the reaction system tends to gel. Undesirable.

Further, it is essential that step {3'' be performed in an inert gas atmosphere. Otherwise, the reaction system tends to gel,
In addition, the unsaturated polyester obtained is likely to be colored. Reaction product mixture obtained in step ①.

} has a molecular weight in the range of 400 to 800 and contains virtually no volatile components. The amount of inert gas introduced can be increased compared to the method involving components.Therefore, the method of the present invention can shorten the time required for dehydration condensation, thereby reducing transesterification and other side reactions of the unsaturated polyester obtained. can be controlled, and an excellent unsaturated polyester with stable quality can be obtained.Step '3' is continued until the acid value of the obtained unsaturated polyester is within the range of 15 to 60. The time required for this is usually 2~
It is 5 hours.

If the acid value of the unsaturated polyester obtained does not fall within the range of 15 to 60, an unsaturated polyester resin derived from such an unsaturated polyester and a polymerizable unsaturated monomer may be added with an additive such as Mg0. This is undesirable because the thickening properties are poor when a viscosity agent is applied, and the effect is not well expressed when a thixotropic agent such as silicic anhydride is used. Unsaturation obtained according to the method of the invention. In order to produce unsaturated polyester resin from polyester (1) and polymerizable unsaturated monomer (b), the conventional method is to mix unsaturated polyester and polymerizable unsaturated monomer to produce unsaturated polyester resin. Any known method can be used.

Examples of the polymerizable unsaturated monomer (0) used in the present invention include vinyl compounds such as styrene, chlorostyrene, Q-methylstyrene, vinyltoluene, divinylbenzene, and vinyl acetate; methyl acrylate, methyl methacrylate, glycidyl methacrylate, 2 - Esters of acrylic acid or methacrylic acid such as hydroxyethyl methacrylate and ethylene diacrylate; esters of allyl alcohol such as diallyl phthalate, dimethallyl phthalate and allyl propionate; or allyl glycidyl ether, ethylene diallyl ether, etc. Examples include ethers of allyl alcohol, and one or a mixture of two or more of these monomers can be used.

The unsaturated polyester resin thus obtained according to the present invention can be cured by the same means as conventional unsaturated polyester resins, and can be used in paints, metallization, cast products, resin concrete, putty, etc. It can be used for various purposes such as fiber-reinforced unsaturated polyester resin.

According to the method of the present invention, when obtaining the unsaturated polyester constituting the unsaturated polyester resin, not only can the reaction time, which normally takes 12 to 1 hour in conventional condensation methods, be shortened to 4 to 6 hours, The obtained unsaturated polyester (1) has performance that is no different from that of the conventional condensation method in terms of hue and copolymerization reactivity with the polymerizable unsaturated monomer (0).

More surprisingly, the cured product of the unsaturated polyester resin obtained based on the present invention has better water resistance, heat resistance, It was found that it exhibited better mechanical properties. This is an unexpected effect of the present invention. Hereinafter, the present invention will be explained in more detail using examples, but the present invention is of course not limited to the scope of these examples.

In addition, "parts" in the examples indicate parts by weight, and the following ( )
The numbers inside indicate the molar ratio. Also, the acid value is JISK-69
The hydroxyl value was measured according to the method described in No. 01 and the pyridine-acetic anhydride method of the standard oil and fat analysis test method (established by the Japan Oil Chemists' Association). Example 1 Step '1}: 74 parts (0.5) of phthalic anhydride and maleic anhydride were placed in a pressure cooker equipped with a heating device, a cooling device, a heating device, a condenser, a gas introduction pipe, a liquid injection device, and a thermometer. 4 parts (0.5), and 18. ethylene glycol.
6 parts (0.3) were added, the inside of the system was replaced with nitrogen gas, and the system was sealed.

By reacting this system at a temperature of 110 pm for 15 minutes, a reaction product mixture 'I' having a carboxyl group concentration of 0.37 equivalent/100 pm was obtained. Step '2}: Next, after raising the temperature in the system to 120%, propylene oxide
When 2.2 parts (0.9) was introduced over 60 minutes, the temperature in the system became 183 qo and the gauge pressure reached a maximum of 0.7 kg/fu.

By keeping it at this temperature for 15 minutes, the acid value increases and the hydroxyl value increases to 80.
A reaction product mixture 'o} with a molecular weight of 645 was obtained. When a portion of the reaction product mixture [〇] was taken out, cooled, and examined for properties, it was found to be a transparent, uniform, and viscous liquid. Also, as a result of NMR analysis, 0.5 mol of phthalic acid residue, 0.15 mol of fumaric acid residue, 0.35 mol of maleic acid residue, 0.3 mol of ethylene glycol residue, and 0.5 mol of propylene glycol residue. Mol and dipropylene glycol residues 0
．． It was found that the composition was composed of 2 moles. Step {31: Next, after the reaction system is made into an open system, the temperature of the system is decreased to 21
An unsaturated polyester having an acid value of 31 and a hydroxyl value of 27 (hereinafter referred to as polyester "1") was heated to a temperature of 0.0 mm and subjected to dehydration condensation for 170 minutes while introducing nitrogen.

) was obtained. Polyester "1" has a pale leet color and is transparent, and as a result of NMR analysis, it contains 0.5 mol of phthalic acid residue, 0.48 mol of fumaric acid residue, 0.02 mol of maleic acid residue, and 0.5 mol of ethylene glycol residue. 3 moles, 0.5 moles of propylene glycol residues and 0.5 moles of dipropylene glycol residues.
It was composed of 2 moles.

Next, 65 parts of polyester "1" were mutually dissolved together with 35 parts of styrene and 0.01 part of hydroquinone to form an unsaturated polyester resin (hereinafter referred to as resin "1").

) was obtained. Physical properties of resin “1” and resin “1” 100
Cobalt octenoate (metal content 8% by weight) 0.2 parts
parts and methyl ethyl ketone peroxide (peroxide content 55% by weight)1. After injecting the resin liquid containing Isobe between two glass plates and curing it, 110 qo
Table 1 shows the physical properties of the cured product obtained by post-curing at a temperature of 2 hours. Comparative Example 1 In Example 1, 0.0% zinc acetate was added as a catalyst in the reaction system.
An unsaturated polyester resin (hereinafter referred to as comparative resin "1") was prepared in the same manner as in Example 1 except that 0.015 parts was coexisting.

) was obtained. At that time, step {1} was performed at a reaction temperature of 11 mm. The carboxyl group concentration of the resulting reaction product mixture was 0.41 equivalent/100 equivalents. In addition, the reaction temperature in step (1) is within the range of 120 to 180, and the maximum gauge pressure is 0.6.
k9/me, and the acid value of the reaction product mixture obtained is 8.
1, the hydroxyl value was 92, and the molecular weight was 648. Furthermore,
Step '3' was carried out at a reaction temperature of 210 pm. The acid value of the obtained unsaturated polyester was 28. Moreover, the total reaction time was 4 hours. Comparative Example 2 In Example 1,
An unsaturated polyester resin (hereinafter referred to as comparative resin "B") was prepared in the same manner as in Example 1 except that 36.0 parts (0.58) of ethylene glycol and 33.6 parts (0.58) of propylene oxide were used. It is called.

) was obtained. At this time, Step 1 was carried out at a reaction temperature of 110 oo. The carboxyl group concentration of the resulting reaction product mixture was 0.63 equivalents/100 equivalents. The reaction temperature in step ① is within the range of 120 to 181℃, and the maximum gauge pressure is 0.6k9.
', and the acid value of the reaction product mixture obtained was 157.
, the hydroxyl value was 181, and the molecular weight was 332. Process'
The reaction temperature of 3' was 21,000, and the acid value of the obtained unsaturated polyester was 26. Also, the total reaction time was 7.
It was bug time. Comparative Example 3 Into the same reaction vessel as used in Example 1, 74 parts of phthalic anhydride (
0.5), 4 parts (0.5) of maleic anhydride, and 6.2 parts (0.1) of ethylene glycol, and the system was purged with nitrogen gas and sealed.

Next, after raising the temperature in the system to 13,000℃, 64 parts (1.1) of propylene oxide was introduced over 13 minutes, and at the end of the introduction, the temperature in the system was 15%.
The pressure was 7.3k9/m. Thereafter, the pressure in the system became constant (1.4 k9') after every 5 flows, and the reaction was completed. 65 parts of the obtained unsaturated polyester, 35 parts of styrene, and 0.01 part of hydroquinone were mutually dissolved to form an unsaturated polyester resin (hereinafter referred to as comparative resin "m").
It is called. ) was obtained. Comparative Example 4 An unsaturated polyester resin having the same composition as resin "1" (hereinafter referred to as comparative resin "W") was produced by a conventionally known condensation method.

) was obtained. The manufacturing method is as follows. 0.5 mol of phthalic anhydride was placed in a four-necked flask equipped with a heating device, a rope device, a gas inlet tube, a partial condenser, and a thermometer.
Maleic anhydride 0.5 mol, ethylene glycol 0.3
mol, propylene glycol in a ratio of 0.52 mol and dipropylene glycol in a ratio of 0.2 mol, and dehydrated and condensed at 200 pm in a nitrogen stream to obtain an acid value of 25 and a hydroxyl value of 3.
An unsaturated polyester of No. 3 was obtained.

Next, 65 parts of this unsaturated polyester was mutually melted together with 35 parts of styrene and 0.01 part of hydroquinone to obtain an unsaturated polyester resin. Table 1 shows the physical properties of comparative resins "1" to "N" obtained in Comparative Examples 1 to 4 and the physical properties of the respective cured products.

Section 1 Table *1 Curing characteristics: JIS K-6901K 80℃ high damage side characteristics.

*2 Storage stability: After putting one resin in a 1 ml tin plate and sealing it, store it at 40C and measure the time (days) until the resin turns into a shell *3 Water resistance: 25x 75×3
Boil other resins on the skin in ion-exchanged water and measure the time until cracks appear. From the results of the above examples and comparative examples, the following points are clear. {i) As is clear from comparing Example 1 and Comparative Example 1, in the case of Comparative Example 1 in which a catalyst coexists in the reaction system, although the reaction time is somewhat shortened, 'a' cannot be obtained. However, it is difficult to achieve the object of the present invention because the haze of the unsaturated polyester resin deteriorates, making it unsuitable for applications requiring excellent appearance, and decreasing storage stability. Can not.

{Example} From the comparison between Example 1 and Comparative Example 2, it is clear that when the proportion of dihydric alcohol used exceeds the range of the method of the present invention, (a) the reaction time becomes longer, {b- the curing properties become worse (that is, the maximum exothermic temperature decreases).

), 'c} It can be seen that there are disadvantages in that the physical properties of the cured product are reduced, and in particular, the heat distortion temperature and water resistance are significantly reduced. From the comparison between Example 1 and Comparative Example 3,
If the proportion of dihydric alcohol used is small and out of the range of the method of the present invention, {a} the unsaturated polyester will exhibit a strange odor, and tb) the physical properties of the unsaturated polyester resin and its cured product will deteriorate significantly. It is clear that this will cause a disadvantage. 0 Comparing Example 1 and Comparative Example 4, the resin "1" obtained by the method of the present invention has a lower level of resin liquid as compared to the comparative resin "W" obtained by the conventional condensation method. It is clear that it has excellent curing properties (particularly maximum exothermic temperature), and also has excellent physical properties when made into a cured product, particularly in terms of heat distortion temperature and water resistance.

Example 2 68.6 parts (0.70) of maleic anhydride, 44.4 parts (0.30) of phthalic anhydride, 34.2 parts (0.38) of 1,3-butylene glycol and 46 parts of propylene oxide .4 parts (0.80) of an unsaturated polyester resin (hereinafter referred to as resin "0") in the same manner as in Example 1.

) was obtained. At that time, step m was performed at a reaction temperature of 110 do. The carboxyl group concentration of the resulting reaction product mixture was 0.49 equivalents/100 equivalents. The reaction temperature in step {2) is within the range of 120 to 178°C, and the maximum gauge pressure is 0.
．． The resulting reaction product mixture {o} had an air value of 121, a hydroxyl value of 99, and a molecular weight of 509. The reaction temperature in step (2) was 210 qo, and the acid value of the obtained unsaturated polyester was 41. Also, the total reaction time is 3. It was time. Table 2 shows the physical properties of the resin "B" and its cured product.

Comparative Example 5 In step '1} of Example 2, phthalic anhydride and maleic anhydride were heated to 18,000 ℃ in advance, and then 1,3-butylene glycol was added at that temperature and reacted for 18 minutes to form a reaction product. An unsaturated polyester resin (hereinafter referred to as comparative resin "V") was prepared in the same manner as in Example 2 except that the mixture was obtained.

) was obtained. At this time, the carboxyl group concentration of the reaction product mixture obtained in step '1} was 0.53 equivalent/100 units. The reaction temperature in step (2) is within the range of 120 to 181°C,
The highest gauge pressure was 0.7k9', and the resulting reaction product mixture had an acid value of 118, a hydroxyl value of 107, and a molecular weight of 497. The reaction temperature in step {3} was 210q0, and the acid value of the obtained unsaturated polyester was 39.
Also, the total reaction time was 4. It was childhood. Comparative resin “V
'' and the physical properties of the cured product are shown in Table 2.

Table 2 As shown in Table 2, when the reaction temperature in step '11 was higher than the range of the method of the present invention, the hue and storage stability were extremely deteriorated.

Examples 3 to 9 Unsaturated polyester resins were obtained using the same procedure as in Example 1.

At that time, the reaction conditions in steps [1', [2} and [3}' are as shown in Table 3, and the characteristics of each unsaturated polyester resin are shown in Table 3. It was exactly as expected. Table 3 *1 Composition: Each composition ○ The numbers in the upper row indicate parts by weight, and the numbers in parentheses in the lower row indicate the molar ratio.

*2 Glycol: PG; Flopylene glycol, D
PG: dibropylene glycol, 1,3-BG: butylene glycol, DEG: soethyl glycol, NPG
: Neobentyl glycol, EG; Ethylene glycol*3 [COOH]: Comparative example of carboxyl group concentration of reaction product mixture) 6 Into the same reaction pot as used in Example 1, 397 parts of phthalic anhydride (0.5 ), 263 parts (0.5) of maleic anhydride, 14.4 parts (0.15) of water, and 1.25 parts (0.006) of sodium hydroxide,
After replacing the inside of the system with nitrogen, the temperature was raised to 100°C.

Next, 28 parts (0.9) of propylene oxide were continuously introduced while maintaining the pressure in the system at 2 to 2.2 k9', the introduction was completed in 60 minutes, and then 1
The pressure inside the powder system is constant (1.3k9/k),
The reaction has finished. The resulting reaction product mixture had a white, transparent appearance and an acid value of 119, and upon cooling, white needle crystals precipitated. Next, the reaction product mixture was maintained at 210oC for 3 hours to obtain an unsaturated polyester having an acid value of 107 and a hydroxyl value of 0 (hereinafter referred to as comparative polyester "W-1"). Next, take 77 parts of comparative polyester "No-1",
After the temperature was brought down to 110 degrees zero, 24 parts (0.17) of propylene oxide was further introduced to produce an unsaturated polyester having an acid value of 33 and a hydroxyl value of 56 (hereinafter referred to as comparative polyester "W-2").

) was obtained. Comparative polyester "W-2" was significantly colored and had a strange odor.

Next, compare polyester "W-1", comparative polyester "
Machi-2'' was taken and mutually dissolved with 35 parts of styrene and 0.01 part of hydroquinone to form an unsaturated polyester resin (hereinafter, the former will be referred to as comparative resin "W-1", and the latter will be referred to as comparative resin "W-1"). 2) was obtained. Comparative resin
W-1" was cloudy and opaque. In addition, comparative resin “no-2
'' was transparent, but its hue (Hazen) was extremely poor, exceeding 300. As described above, it has not been possible to obtain the unsaturated polyester resin targeted by the present invention using the conventionally known oxide method. Comparative Example 7 103.6 parts (0.70) of phthalic anhydride, 29.4 parts (0.30) of maleic anhydride, 30.7 parts (0.26) of 1,6-hexylene glycol, and ethylene oxide An unsaturated polyester resin (hereinafter referred to as comparative resin "skin") was prepared in the same manner as in Example 1 except that 37 parts (0.1 parts) was used.

) was obtained. The hue (Hazen) of the comparison resin “skin” is 180
The storage stability was 55 days. Incidentally, when producing the comparative resin "Hada", the reaction temperature of Koen 1 was 110 qo, and the carboxyl group concentration of the resulting reaction product mixture was 0.2 ta equivalent/100 qo. In addition, in the process [2L, the reaction temperature is within the range of 120 to 171℃, and the maximum gauge pressure is 1.8K.
The resulting reaction product mixture had an acid value of 78, a hydroxyl value of 63, and a molecular weight of 796. In step {3}', the reaction temperature was 210q0, and the acid value of the unsaturated polyester obtained was 31. Also, the total reaction time is 5. It was beat time. This comparative example satisfies all the constituent requirements of the present invention except for the carboxyl group concentration of the reaction product mixture obtained in step '1}, but both the hue and storage stability of the obtained unsaturated polyester resin are It was inferior to the resins derived according to the invention.

Claims (1)

[Claims] 1. Unsaturated polyester (I) and polymerizable unsaturated monomer (
In producing an unsaturated polyester resin from (II), the unsaturated polyester (I) is used in the following steps (1) and (2).
) and (3). A method for producing an unsaturated polyester resin. Step (1): α/β-unsaturated dicarboxylic acid anhydride (a)
dicarboxylic acid anhydride containing at least 20 mol% of
A) and the dicarboxylic anhydride (A) 0.
0.33 by reacting dihydric alcohol (B) in an amount of 25 mol or more and less than 0.40 mol in an inert gas atmosphere, without catalyst, within a temperature range of 90 to 150°C.
A step of obtaining a reaction product mixture (a) containing carboxyl groups at a concentration of ~0.65 equivalents/100 g. Step (2): Add alkylene oxide (C) to the reaction product mixture (a) in an inert gas atmosphere, without catalyst, 110-1
A reaction product mixture (b) which is reacted within a temperature range of 90°C and has an acid value within the range of 70 to 160, a difference between the oxidation value and the hydroxyl value is 30 or less, and a molecular weight within the range of 400 to 800. The process of obtaining Step (3): The reaction product mixture (b) is heated to an acid value of 15 to 60 within a temperature range of 180 to 240°C in an inert gas atmosphere.
A step of obtaining an unsaturated polyester by dehydration condensation until it falls within the range of . 2. The method for producing an unsaturated polyester resin according to claim 1, wherein the dihydric alcohol is mainly composed of ethylene glycol. 3. The method for producing an unsaturated polyester resin according to claim 1, wherein the dihydric alcohol is mainly composed of diethylene glycol. 4. The method for producing an unsaturated polyester resin according to claim 1, wherein the dihydric alcohol is mainly composed of propylene glycol. 5. The method for producing an unsaturated polyester resin according to claim 1, wherein the dihydric alcohol is mainly composed of dipropylene glycol. 6. The method for producing an unsaturated polyester resin according to claim 1, wherein the dihydric alcohol is mainly composed of 1,3-butylene glycol.