JPH08269181A - Production of high-molecular weight unsaturated polyester - Google Patents

Abstract

PURPOSE: To obtain at low cost a polyester excellent in boiling water resistance, toughness, heat distortion temperature, etc., useful for e.g. fiber-reinforced plastics, by esterification between saturated polybasic acid(s) and a polyhydric alcohol followed by adding an unsaturated polybasic acid to the system to carry out a further esterification followed by deglycolation. CONSTITUTION: Esterification is conducted between a saturated polybasic acid (anhydride) component containing 5-40mol% of compound(s) of formula, HOOC (CH2 )n COOH ((n) is 4-10) (e.g. adipic acid, sebacic acid) and a polyhydric alcohol component to an esterification rate of >=60%, and an α,β-unsaturated polybasic acid (anhydride) component is then added to the reaction system to carry out a further esterification; and when the acid value of the reaction system comes to 90-15, the pressure is reduced to 93-7hPa to conduct a deglycolation, thus the objective polyester with a number-average molecular weight of >=3500 is obtained.

Description

Detailed Description of the Invention

[0001]

The present invention relates to fiber reinforced plastics (FRP), gel coat, paint, casting, SMC, BM.
The present invention relates to a method for producing a high molecular weight unsaturated polyester which is useful in various fields such as C and has good physical properties such as boiling water resistance, toughness and heat distortion temperature.

[0002]

2. Description of the Related Art Unsaturated polyester resin (in the present specification, in order to avoid confusion, a "resin" is attached to a type in which a monomer is used in combination, and a type in which a monomer is not used is simply referred to as "unsaturated polyester") Is known to have excellent moldability, mechanical strength, chemical, physical and electrical properties. Therefore, this unsaturated polyester resin is used as a FRP used in bathtubs, unit baths, fishing boats, tanks, housings, etc., as a non-FRP used in paints, castings, resin concrete, and as a molding material for SMC and BMC. Widely used.

As described above, the unsaturated polyester resin has a wide variety of uses, but boiling water resistance, chemical resistance and toughness are particularly important performances.

However, it has been pointed out that the conventional unsaturated polyester resin is inferior in toughness. For example, tensile elongation is an index of toughness, but that of conventional unsaturated polyester resin is 2.5% or less, which is less than 4 to 5% of vinyl ester resin. Further, generally, when toughness is imparted, the heat distortion temperature is lowered, and the boiling water resistance is also lowered, so that the use is limited. Therefore, boiling water resistance,
An unsaturated polyester resin having good chemical resistance and excellent toughness and heat distortion temperature is desired.

As a method of satisfying these physical properties, a method of using an ethylene oxide adduct of bisphenol A as a part of a polyhydric alcohol component, a method of modifying an end group of an unsaturated polyester with glycidyl methacrylate, etc. However, these raw materials are expensive and therefore increase the manufacturing cost and are not desirable.

Therefore, some of the inventors of the present invention have previously proposed a method for producing an unsaturated polyester which can improve boiling water resistance, toughness and heat distortion temperature without using expensive raw materials (special feature). Kaihei 6-200002). This production method has an acid value of 90 to 90 during the esterification reaction of various raw materials.
When the temperature reached 25, the reaction system was depressurized to 10 Torr or less,
It is characterized in that the unreacted polyhydric alcohol component is removed. Further, it is said that after the esterification reaction, it is preferable to carry out a deglycol reaction under a further high reduced pressure in order to increase the molecular weight. According to this production method, an unsaturated polyester resin having a well-balanced boiling water resistance, toughness and heat distortion temperature can be obtained at low cost and is useful.

[0007]

However, the above-mentioned prior art production method requires a high degree of depressurization during the esterification reaction and / or the deglycolization reaction, and in order to achieve such high depressurization. However, there is still room for cost improvement because it is necessary to change equipment such as increasing the capacity of the vacuum pump and increasing the airtightness of the reaction system. The present inventors have solved the conventional problems as described above, at a lower cost than the prior art, and a method for producing a high molecular weight unsaturated polyester having a balanced boiling water resistance, toughness and heat distortion temperature. It is intended to be provided.

[0008]

Means for Solving the Problems As a result of intensive studies by the present inventors, the use of a specific saturated polybasic acid or an anhydride component thereof in a specific ratio provides toughness and a heat distortion temperature. It was found that a high molecular weight unsaturated polyester having good boiling water resistance was obtained, and the present invention could be completed.

That is, in the present invention, the acid component of the α, β-unsaturated polybasic acid or its anhydride component and the saturated polybasic acid or its anhydride component and the polyhydric alcohol component are subjected to an esterification reaction to deglycolize. In the method for producing a high molecular weight unsaturated polyester including a step of reacting, with respect to the α, β-unsaturated polybasic acid or an anhydride component thereof and the acid component of the saturated polybasic acid or an anhydride component thereof, As the saturated polybasic acid or its anhydride component, the following general formula (1)

[0010]

Embedded image HOOC (CH ₂ ) _n COOH (1)

An alkylenedicarboxylic acid represented by the formula (wherein n has a value of 4 to 10) is used in an amount of 5 to 40 mol%, and the esterification reaction is carried out by using the saturated polybasic acid or its anhydride component and polyanionic acid. The first step reaction in which the polyhydric alcohol component is reacted until the esterification reaction rate becomes 60% or more, and the α, β-unsaturated polybasic acid or its anhydride component is added to the reaction system of the first step reaction. And a second step reaction in which the acid value of the reaction system in the second step reaction is 90 to 15
At that time, the pressure was reduced to 93 hPa to 7 hPa, a deglycol reaction was performed, and the number average molecular weight was 3,50.
The present invention provides a method for producing a high molecular weight unsaturated polyester, which is characterized in that it is 0 or more.

The present invention also provides the above-mentioned production method, wherein the alkylenedicarboxylic acid is adipic acid (n = 4).

The present invention further provides the above-mentioned production method, wherein the alkylenedicarboxylic acid is sebacic acid (n = 8).

Furthermore, the present invention provides the above-mentioned production method, wherein the alkylenedicarboxylic acid is used in an amount of 7 to 35 mol%.

In the present invention, the esterification reaction rate is 80%.
The present invention provides the above-mentioned production method in which the first-step reaction is continued.

Further, in the present invention, the acid value of the reaction system is 70 to 4
The present invention provides the above-mentioned production method, in which the pressure is reduced to 60 to 7 hPa and the deglycolization reaction is carried out when the pressure becomes 0.

Furthermore, the present invention provides a method for producing an unsaturated polyester resin, characterized in that the high molecular weight unsaturated polyester obtained by the above-mentioned production method is blended with a monomer copolymerizable therewith. It is a thing.

The present invention will be described in more detail below.
(Saturated polybasic acid or its anhydride component) The saturated polybasic acid or its anhydride component used in the present invention has the following general formula (1).

[0019]

Embedded image HOOC (CH ₂ ) _n COOH (1)

(Where n has a value of 4 to 10)

It is essential to use an alkylenedicarboxylic acid represented by the following, which is one of the features of the present invention. The alkylenedicarboxylic acid of the general formula (1) is used in an amount of 5 to 5 with respect to the total amount of the α, β-unsaturated polybasic acid or its anhydride component and the acid component of the saturated polybasic acid or its anhydride component. 40 mol%, preferably 7 to 3
5 mol% is good. If the amount of the alkylenedicarboxylic acid used is less than 5 mol%, the toughness is insufficient, and 40
If it exceeds mol%, the heat distortion temperature and boiling water resistance become insufficient. In the general formula (1), adipic acid with n = 4 and sebacic acid with n = 8 are preferable in the present invention. It is also possible to use a saturated polybasic acid other than the alkylenedicarboxylic acid of the general formula (1) or an anhydride thereof together, for example, isophthalic acid, tetrahydrophthalic anhydride or the like. Hereinafter, unless otherwise specified, the alkylenedicarboxylic acid represented by the general formula (1) and another saturated polybasic acid used in combination as necessary are simply referred to as “saturated polybasic acid component”.

(Α, β-Unsaturated Polybasic Acid or Anhydride Component Thereof) The α, β-unsaturated polybasic acid or its anhydride component usable in the present invention is not particularly limited, but for example, maleic anhydride, Fumaric acid and the like are generally used.

(Polyhydric alcohol component) The polyhydric alcohol component that can be used in the present invention can be appropriately selected in consideration of the fact that the production cost does not increase, but as an example, it is 1013 hPa (1 atm, 760 mmHg). It is preferable to use a glycol component having a boiling point of 320 ° C. or less, such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,6-hexanediol, neopentyl glycol, hydrogenated bisphenol A.
Etc. In addition, a polyhydric alcohol component having a boiling point at 1013 hPa higher than 320 ° C. can be used in combination if necessary, but generally, when a large amount of such a component is used, a deglycolization reaction under reduced pressure with a low degree is performed. Therefore, it is preferable that the use ratio thereof be 30% by weight or less based on the whole polyhydric alcohol component.

(Ratio of Three Components Used) The ratio of alkylenedicarboxylic acid used is 5 to 40 with respect to the total of the α, β-unsaturated polybasic acid or its anhydride component and the acid component of the saturated polybasic acid component. If it is mol%, the use ratio of the α, β-unsaturated polybasic acid or its anhydride component, the saturated polybasic acid component and the polyhydric alcohol component is not particularly limited and is appropriately determined. However, in consideration of the physical properties of the resulting unsaturated polyester, the proportion of the α, β-unsaturated polybasic acid or its anhydride component used is usually 70 to 40 mol% in all the acid components.

(Esterification reaction) The present invention is also characterized in that the esterification reaction of the above-mentioned three components is carried out by a total of two stages of reaction. First-Step Reaction The first-step reaction consists of an esterification reaction between a saturated polybasic acid component and a polyhydric alcohol component. In the first-step reaction, for example, while nitrogen is introduced, the esterification proceeds by gradually increasing the temperature from the temperature at which both components do not distill the reaction water together. The maximum reaction temperature is, for example, 20
It is about 0 to 215 ° C., and the esterification reaction rate of both components is 60% or more, preferably 80% or more. When the reaction rate is less than 60%, the boiling water resistance of the resulting unsaturated polyester may be poor.

Second-step reaction The second-step reaction is carried out by adding α, to the reaction system when the esterification reaction rate of the saturated polybasic acid component and the polyhydric alcohol component becomes 60% or more in the first-step reaction. A β-unsaturated polybasic acid or its anhydride component is added, and the temperature of the reaction system is gradually raised to 180 to 230 ° C. while flowing nitrogen and the reaction system has an acid value of 90 to 15, preferably 70 to It consists of continuing the esterification reaction until 40. The reason for defining the acid value in the second-step reaction in this way is that the deglycolization reaction is a reaction between terminal hydroxyl groups, and it is desirable that the acid value is low considering only the deglycolization reaction (for example, an acid value of less than 15). Also, it is desirable that the polyester prepolymer before the deglycolization reaction has a large molecular weight because the molecular weight increases rapidly in the deglycolization reaction, but in order to reduce the acid value to less than 15, the polyhydric alcohol component should be added in a large amount. Moreover, the reaction time must be lengthened, which increases the cost. On the other hand, when the acid value exceeds 90, the molecular weight of the polyester prepolymer is still small, and the amount of unreacted polyhydric alcohol component distills out under reduced pressure, resulting in a shortage of polyhydric alcohol component. Furthermore, considering that the esterification reaction is also performed in parallel in the depressurization reaction during deglycolization, the acid value is 90 to 15,
It is preferably specified to 70-40.

As described above, the reason why the esterification reaction is carried out in two steps in the present invention is that the reactivity between the alkylenedicarboxylic acid represented by the general formula (1) and the polyhydric alcohol component is α, β-unsaturated. It is lower than that of the basic acid or its anhydride component, and if all components are esterified at the same time, the unreacted product of the alkylenedicarboxylic acid or the saturated polybasic acid component used in combination increases, which reduces boiling water resistance. Because it does. By the esterification reaction in the first step, the alkylenedicarboxylic acid or other saturated polybasic acid component used in combination efficiently reacts with the polyhydric alcohol component, and then in the second step reaction, α, β-unsaturation By adding the polybasic acid or its anhydride component, the number average molecular weight of the resulting unsaturated polyester is increased, and the boiling water resistance and chemical resistance, as well as the toughness and heat distortion temperature are improved.

(Deglycol reaction) In the present invention,
After the acid value of the reaction system becomes 90 to 15 by the above esterification reaction, a deglycol reaction is subsequently performed. The deglycolization reaction is carried out in the presence of a catalyst at a temperature of 180 to 230 ° C., preferably 190 to 215 ° C., until the number average molecular weight of the unsaturated polyester reaches a desired molecular weight of 3,500 or more,
Usually 2 to 6 hours, pressure 93 to 7 hPa, preferably 60
It is performed under reduced pressure of ˜7 hPa. At this time, the pressure is 93
When it exceeds hPa, the increase of the molecular weight is slow, and conversely 7 hPa
If it is less than the above range, the facility cost is increased as described above, which is not preferable. As the catalyst, organic compounds of titanium such as tetraisopropyl titanate, acetylacetonate of titanium; organic salts of zinc such as zinc acetate; tin compounds such as dibutyltin oxide; inorganic compounds of antimony,
For example, antimony trioxide or the like can be used. The amount used is 0.01 parts by weight or more, preferably 0.05 to 0.2 parts by weight, based on 100 parts by weight of the charged amount of the above three components. The catalyst is preferably added at the start of the deglycolization reaction, but since these catalysts can also be used as the esterification reaction catalyst, they may be added at the start of the esterification reaction.

(Unsaturated Polyester Resin) The unsaturated polyester resin obtained as described above is dissolved in a monomer to obtain an unsaturated polyester resin. Typical examples of the monomer that can be used include styrene, but vinyltoluene, methyl methacrylate, diallyl phthalate, diallyl terephthalate prepolymer and the like can be used.

[0030]

In the conventional esterification reaction of unsaturated polyester, the esterification reaction proceeds while the condensed water is fractionally removed at 180 to 230 ° C. while flowing nitrogen, and the acid value is 9
When it becomes 0 or less, the pressure is reduced to 93 to 53 hPa, and the removal of condensation water is further promoted to increase the molecular weight. However, the number average molecular weight is less than 3,500 and equilibrium occurs. Only the average molecular weight increases, leading to gelation. Increasing the molecular weight also increases boiling water resistance, chemical resistance, toughness, and heat distortion temperature. The present inventors have found a method of increasing the number average molecular weight by a deglycolization reaction under high pressure reduction conditions as described above, but it has been necessary to solve the problem of high cost due to high pressure reduction. It was found that high-pressure reduction does not necessarily require high decompression, but can be achieved by selecting the reaction method and conditions. It is well known that polyhydric alcohols, saturated polybasic acids or their anhydrides, which generally impart toughness, lower the heat distortion temperature and boiling water resistance. The present inventors use a alkylenedicarboxylic acid in a specific ratio and set the number average molecular weight to 3,500 or more to impart toughness, heat distortion temperature, and high molecular weight unsaturated polyester excellent in boiling water resistance. It was found that the above was obtained, and the present invention could be completed.

[0031]

EXAMPLES The present invention will be described below with reference to examples. Reference Example 1 A 2-liter 4-neck separable flask equipped with a stirrer, temperature controller, fractionating condenser, distillate collection trap, manometer, vacuum pump, and nitrogen inlet tube was charged with 479 g of propylene glycol (6.3 mol). ), 222 g of phthalic anhydride (1.
(5 mol) and 228 g (1.56 mol) of adipic acid were charged, and the temperature was gradually raised while introducing nitrogen. 174 ° C
Although water of reaction started to be discharged at, the temperature was gradually raised and the temperature was kept at 205 ° C. to carry out the esterification reaction. When the acid value reached 5, the temperature was lowered to 130 ° C and the maleic anhydride 28
8 g (2.94 mol) was added and the temperature was gradually raised. 1
Although water of reaction started to come out at 93 ° C, the temperature was gradually raised to 215 ° C and maintained. 4 when the acid value reaches 63
The pressure was reduced to 0 hPa and the reaction was performed for 2 hours. An unsaturated polyester having a number average molecular weight of 2,600, a weight average molecular weight of 6,500 and an acid value of 30 was obtained. Then, the temperature of the reaction system was lowered to 170 ° C., 0.18 g of hydroquinone and styrene monomer (40%) were added and uniformly dissolved to obtain an unsaturated polyester resin.

Reference Example 2 In the same apparatus as in Reference Example 1, 479 g of propylene glycol was added.
(6.3 mol), 378 g of isophthalic acid (2.28 mol)
Then, 114 g (0.78 mol) of adipic acid was charged and the esterification reaction was carried out in the same manner as in Reference Example 1. When the acid value reached 10, the temperature was lowered to 130 ° C., 288 g (2.94 mol) of maleic anhydride was added, and the temperature was gradually raised to 21
Raised to 5 ° C. While maintaining this temperature, when the acid value reached 58, the pressure was reduced to 40 hPa and the reaction was carried out for 2 hours. An unsaturated polyester having a number average molecular weight of 3,100, a weight average molecular weight of 9,500 and an acid value of 32 was obtained. Subsequently, the temperature of the reaction system was lowered to 170 ° C., and 0.22 g of hydroquinone and styrene monomer (40%) were added and uniformly dissolved to obtain an unsaturated polyester resin.

Example 1 479 g of propylene glycol was placed in the same apparatus as in Reference Example 1.
(6.3 mol), 222 g (1.5 mol) of phthalic anhydride and 228 g of adipic acid (26 mol% of the acid component) were charged and the esterification reaction was carried out in the same manner as in Reference Example 1. When the acid value reaches 62 (1st stage reaction, esterification reaction rate 8
4.7%), the temperature was lowered to 130 ° C., 288 g (2.94 mol) of maleic anhydride was added, and the temperature was gradually raised to 21%.
Raised to 5 ° C. Maintaining this temperature (second stage reaction), when the acid value reached 63, 0.22 g of hydroquinone and 1.1 g of antimony trioxide were added, the pressure inside the system was reduced to 40 hPa, and the reaction was carried out at 215 ° C for 3 hours. (Deglycol reaction). The temperature was further lowered to 190 ° C. and the reaction was carried out for 3 hours. Number average molecular weight 5,000, weight average molecular weight 20,5
An unsaturated polyester having an acid value of 00 and an acid value of 10 was obtained. Subsequently, 0.18 g of hydroquinone and styrene monomer (40%) were added and uniformly dissolved to obtain an unsaturated polyester resin.

Example 2 479 g of propylene glycol was placed in the same apparatus as in Reference Example 1.
(6.3 mol), 378 g of isophthalic acid (2.28 mol)
Then, 114 g of adipic acid (13 mol% of the acid component) was charged, and the esterification reaction was carried out in the same manner as in Reference Example 2. When the acid value reaches 10 (esterification reaction rate 97.5%)
Then, the temperature is lowered to 130 ° C. and maleic anhydride 28
8 g (2.94 mol) was added and the temperature was gradually raised to 215 ° C. While maintaining this temperature, when the acid value reached 63, 0.22 g of hydroquinone and 1.1 g of antimony trioxide were added, the pressure in the system was reduced to 40 hPa, and the reaction was carried out at 215 ° C. for 3 hours. An unsaturated polyester having a number average molecular weight of 4,900, a weight average molecular weight of 19,600 and an acid value of 13 was obtained. Subsequently, 0.18 g of hydroquinone and styrene monomer (40%) were added and uniformly dissolved to obtain an unsaturated polyester resin.

Example 3 150 g of propylene glycol was placed in the same apparatus as in Reference Example 1.
(1.98 mol), neopentyl glycol 449 g
(4.32 mol), 449 g of isophthalic acid (2.70 mol) and 121 g of sebacic acid (0.60 mol, 10 mol% of the acid component) were charged, and the temperature was gradually raised to 205 ° C. Held When the acid value became 55 (esterification reaction rate 84.6%), the temperature was lowered to 130 ° C, 265 g (2.70 mol) of maleic anhydride was added, and the temperature was gradually raised to 215 ° C. It was When this temperature was maintained and the acid value reached 36, hydroquinone 0.22
g, antimony trioxide 1.1g was added, and the system was heated to 40 hP
The pressure was reduced to a and the reaction was carried out at 215 ° C. for 4 hours. An unsaturated polyester having a number average molecular weight of 6,500, a weight average molecular weight of 26,700 and an acid value of 3 was obtained. Subsequently, 0.18 g of hydroquinone and styrene monomer (40%) were added and uniformly dissolved to obtain an unsaturated polyester resin.

(Method of measuring acid value) The method of measuring acid value is described in J.
Specified in IS K6901. In this method, anhydrous acid is measured as a monoacid. The acid value in the present invention is the following method for measuring anhydrous acid as a diacid. For example, 2 g of water is added to 10 g of pyridine, and 1 g of the sample is added.
It is heated at 0 ° C. for 10 minutes to ring-open the anhydrous acid for measurement. Except for the operation of ring opening, it is the same as the above JIS method.

(Measurement of Molecular Weight) The number average molecular weight and the weight average molecular weight in this specification are measured under the following GPC conditions. Measuring instrument: Showa Denko SYSTEM11; Column: Shodex, KF805, 803 and 80
2 1 piece each, 3 pieces in total; molecular weight: converted to polystyrene, calculation range cuts molecular weight of 260 or less.

With respect to each unsaturated polyester resin obtained in the above Reference Examples and Examples, boiling water resistance, elongation,
The heat deformation temperature, tensile strength, tensile elastic modulus, bending strength and bending elastic modulus were measured. The measurement conditions are described below.

(Preparation of Test Piece for Measurement) 100 g of unsaturated polyester resin obtained in each Reference Example or Example
In addition, 20 g of styrene monomer and 0.04 of dimethylaniline
g and 0.5 g of cobalt naphthenate were added and mixed uniformly, and 1.2 g of Permec N (methyl ethyl ketone peroxide) was added to degas. The obtained resin is cast on a glass plate with a gap of 3 mm and cured at room temperature, then at 110 ° C.
It was post-cured for 2 hours. Each of the obtained flat plates was processed according to the following measurement standards to obtain a test piece for measurement. In addition, the test piece for measurement of boiling water resistance was made by cutting a flat plate into a size of 25 × 80 mm and cutting its cross section into 40
The test piece for measuring the heat distortion temperature, which was ground with No. 0 paper, was made of the above resin in 15 x 15 x 130 mm.
12.5 × 12.5 × 110 mm.

(Measurement of boiling water resistance) 5 with condenser
4 liters of tap water was put into a 1-liter flask and heated by a mantle heater to boil. Five pieces of each of the measurement test pieces were put in this and boiled. The boiling water resistance was defined as the time when star cracks started to occur.

(Measurement of Various Physical Properties) Tensile strength, tensile elastic modulus and elongation, bending strength, bending elastic modulus and heat deformation temperature are JIS K7113, K7203 and K720, respectively.
It measured according to 7207.

(Measurement Results) Table 1 shows the results obtained.
From Table 1, the unsaturated polyester resin prepared by the production method of the present invention shows particularly excellent boiling water resistance, elongation and heat distortion temperature, which are significantly superior to those of Reference Example.
It can be seen that a very well balanced unsaturated polyester was obtained.

[0043]

[Table 1]

[0044]

Industrial Applicability According to the present invention, there is provided a method for producing a high molecular weight unsaturated polyester in which the boiling water resistance, the toughness and the heat distortion temperature are well balanced at a lower cost than the prior art.

Claims (7)

[Claims] 1. A step of subjecting an acid component of an α, β-unsaturated polybasic acid or its anhydride component and an acid component of a saturated polybasic acid or its anhydride component and a polyhydric alcohol component to an esterification reaction and a deglycol reaction. In the method for producing a high molecular weight unsaturated polyester, the saturated polybasic acid or the anhydride component thereof and the saturated polybasic acid or the acid component of the anhydride component are added to the saturated polybasic acid. An alkylenedicarboxylic acid represented by the following general formula (1): HOOC (CH ₂ ) _n COOH (1) (wherein n has a value of 4 to 10) is used as the basic acid or its anhydride component. 5 to 40 mol% is used, and the esterification reaction converts the saturated polybasic acid or its anhydride component and polyhydric alcohol component to an esterification reaction rate of 60.
%, And a second stage reaction in which the α, β-unsaturated polybasic acid or its anhydride component is added to the reaction system of the first stage reaction and further reacted. When the acid value of the reaction system in the second-stage reaction reaches 90 to 15, the pressure is reduced to 93 hPa to 7 hPa and a deglycol reaction is performed to make the number average molecular weight 3,500 or more. And a method for producing a high molecular weight unsaturated polyester. 2. The production method according to claim 1, wherein the alkylenedicarboxylic acid is adipic acid (n = 4). 3. The method according to claim 1, wherein the alkylenedicarboxylic acid is sebacic acid (n = 8). 4. The production method according to claim 1, wherein the alkylenedicarboxylic acid is used in an amount of 7 to 35 mol%. 5. The production method according to claim 1, wherein the first step reaction is continued until the esterification reaction rate is 80% or more. 6. The production method according to claim 1, wherein when the acid value of the reaction system reaches 70 to 40, the deglycolization reaction is performed by reducing the pressure to 60 to 7 hPa. . 7. An unsaturated polyester, characterized in that the high molecular weight unsaturated polyester obtained by the production method according to claim 1 is blended with a monomer copolymerizable therewith. Resin manufacturing method.