TW201437252A - Method for preparing unsaturated polyester, unsaturated polyester and composition for curing - Google Patents

Abstract

A method for preparing unsaturated polyester comprises the following steps: providing phthalic anhydride by-product and glycerol to perform polycondensation reaction and form a prepolymer with acid value of less than 3 mgKOH/g and viscosity ranging from 350 cps to 650 cps. Then fumaric acid is added to carry out polycondensation reaction, wherein the phthalic anhydride by-product comprises 80 wt% or higher of benzoic acid and phthalic anhydride. The method for preparing unsaturated polyester of this invention uses completely glycerol; in addition, during the preparation of unsaturated polyester, benzoic acid of the phthalic anhydride by-product is reacted with glycerol so as to reduce the average functionality to less than three, followed by reaction with phthalic anhydride or fumaric acid, such that gelation can be inhibited during the reaction to prevent worsened fluidity which results in difficult reaction and operation.

Description

Method for preparing unsaturated polyester, unsaturated polyester and curing group Adult

This invention relates to a process for the preparation of unsaturated polyesters, and more particularly to a process for the preparation of unsaturated polyesters using phthalic anhydride by-products and glycerol.

Unsaturated polyester is one of the most commonly used thermosetting resins, and is formed by polycondensation of an unsaturated dibasic acid and a polyhydric alcohol, wherein the polyhydric alcohol is mainly a glycol (such as ethylene glycol). Depending on the desired physical properties, an appropriate amount of glycerin is added. The use of a glycol can make the operation of the reaction easy and the reaction rate is fast, and the glycerin can produce a network structure gel in the process of synthesizing the unsaturated polyester, so that the fluidity is deteriorated, and the reaction is not easy to carry out. Operation, therefore, the preparation of unsaturated polyesters is still mostly based on the use of glycols. However, the cost of the diol is higher than the cost of glycerin, and the unsaturated polyester prepared by using the diol has lower heat resistance and hardness than the unsaturated polyester obtained by using glycerin, so how to use glycerin Replacing the diol used in the past is a subject that can be further broken by those skilled in the art.

The Chinese Patent No. CN102219882 discloses a method for synthesizing an unsaturated polyester resin using glycerin. The preparation method comprises starting a synthesis of a synthetic raw material comprising 0.25 parts by weight to 1.5 parts by weight of glycerin, 1 part by weight of a diol, a monobasic acid and a dibasic acid at 150 ° C to 155 ° C, and then raising the temperature to 208. The reaction is carried out at a temperature of from ° C to less than 210 ° C, and when reacted to an acid value of 45 to 50 mg KOH / g, nitrogen gas is introduced, and the flow rate of the nitrogen gas is 0.5 m ³ /h, after which the reaction is evacuated to an acid value of 25 When the temperature was 30 mgKOH/g, the temperature was lowered to 190 ° C, a polymerization inhibitor and an antifoaming agent were added, and the cooling water was turned off. Then, the mixture was diluted with a crosslinking agent, and when the mixture was sufficiently stirred to 65 ° C or lower, the stirring was stopped. The patent uses glycerin instead of some of the glycols previously used in the preparation of unsaturated polyesters, which greatly reduces the production cost of unsaturated polyesters and improves the economic efficiency of the industry. At the same time, the unsaturated polycondensation obtained by the method The ester has better mechanical strength and is in line with the utility of the manufacturer. However, the diol used in the patent is still not completely replaced by glycerol, so the cost reduction is still limited, and the preparation method is to avoid gelation, process conditions (such as multi-stage temperature regulation). The control or glycerol content is limited and severe. Therefore, the method cannot meet the needs and use benefits of the manufacturer. At the same time, the diol reacts with the monobasic acid, resulting in the formation of the unsaturated polyester. A large number of small molecular weight polymers, which in turn affect the physical properties of the unsaturated polyester (such as tensile strength).

In view of the above, there is still a need to provide a method for preparing an unsaturated polyester which is completely glycerin-free and which is low in cost, and a method for reducing gelation in the process of preparing an unsaturated polyester.

Accordingly, a first object of the present invention is to provide a process for preparing an unsaturated polyester which completely uses glycerin and which reduces the occurrence of gelation.

The method for preparing an unsaturated polyester according to the present invention comprises the steps of: providing a polycondensation reaction of a phthalic anhydride by-product with glycerol to form a prepolymer having an acid value in the range of less than 3 mgKOH/g and a viscosity ranging from 350 cps to 650 cps, followed by adding The fumaric acid is formed by a polycondensation reaction, wherein the phthalic anhydride by-product comprises 80% by weight or more of benzoic acid and phthalic anhydride.

A second object of the invention is to provide an unsaturated polyester.

Thus, the unsaturated polyester of the present invention is obtained by the above process for producing an unsaturated polyester.

A third object of the present invention is to provide a curing composition.

Thus, the curing composition of the present invention comprises: an unsaturated polyester which is subjected to a polycondensation reaction with a phthalic anhydride by-product and glycerin to form a prepolymer having an acid value of less than 3 mgKOH/g and a viscosity ranging from 350 cps to 650 cps. The addition of fumaric acid is carried out to carry out a polycondensation reaction, wherein the phthalic anhydride by-product comprises 80% by weight or more of benzoic acid and phthalic anhydride; and styrene.

The effect of the invention is that the method for preparing the unsaturated polyester of the invention is to completely use glycerin, and in the process of preparing the unsaturated polyester, the benzoic acid in the by-product of the phthalic anhydride is reacted with glycerol to reduce the average functionality to three. Hereinafter, it is further reacted with phthalic anhydride or fumaric acid to reduce the occurrence of gelation during the reaction, thereby avoiding deterioration of fluidity, resulting in difficulty in carrying out and handling the reaction.

The method for preparing the unsaturated polyester of the invention is that the glycerin is completely used, and the cost of the synthetic raw material can be greatly reduced. At the same time, the by-product produced by the preparation of the phthalic anhydride in the invention can not only reduce the waste disposal cost, but can be reduced again. In addition to the cost of the synthetic raw material for preparing the unsaturated polyester, in the process of preparing the unsaturated polyester, the benzoic acid in the by-product of the phthalic anhydride is reacted with glycerin to reduce the average functionality to less than three, thereby reducing the reaction process. The middle gel phenomenon is generated, and then the fluidity is prevented from being deteriorated, so that the reaction is not easy to carry out and the processing operation is performed. At the same time, the reaction temperature can be raised to 210 ° C to 225 ° C, and in addition to accelerating the reaction, the reaction is also carried out at this temperature. It is not easy to produce gelation. Further, the reaction is carried out until the acid value is less than 3 mgKOH/g, and then the fumaric acid is added, and the reaction temperature is lowered to 210 ° C or lower, which can reduce the gelation phenomenon during the reaction. In addition, the cured composition formed by the unsaturated polyester obtained by the present invention and the styrene may have good mechanical properties (such as elongation, pull) in the cured product formed by the subsequent heat treatment of the reinforcing accelerator and the hardener. Extensive strength or bending strength) and thermal properties (such as high heat distortion temperature).

The gel phenomenon described herein refers to a gel body which tends to generate a large amount of network structure during the reaction, so that the overall viscosity becomes so large that the fluidity during the reaction becomes poor. The presence of the gel of the network structure produced by the gelation phenomenon deteriorates the compatibility of the formed unsaturated polyester with styrene, affects the processing property of subsequent treatment, and leads to unsaturated polyester and Styrene is less reactive in the presence of a hardener, which in turn affects the degree of thermal cure. At the same time, the presence of the gel causes the unsaturated polyester to polymerize with styrene, which in turn causes the curing composition to be difficult to store.

The phthalic anhydride by-products described herein refer to the process of preparing phthalic anhydride and obtaining high purity phthalic anhydride by distillation, and the light boilers distilled during the distillation are the by-products of phthalic anhydride described herein, such as benzoic acid and some phthalic anhydride.

The method for preparing an unsaturated polyester according to the present invention comprises the steps of: providing a polycondensation reaction of a phthalic anhydride by-product with glycerol to form a prepolymer having an acid value of less than 3 mgKOH/g and a viscosity ranging from 350 cps to 650 cps, followed by adding a counter The butenedic acid is formed by a polycondensation reaction, wherein the phthalic anhydride by-product comprises 80% by weight or more of benzoic acid and phthalic anhydride. By reacting benzoic acid with glycerol, the gel formation of the network structure can be reduced, and the viscosity is controlled from 350 cps to 650 cps.

The weight ratio of benzoic acid in the by-product of glycerin and phthalic anhydride is less than 0.85, which avoids the formation of a gel which is easy to have a network structure and causes excessive viscosity.

Preferably, the content of the benzoic acid is in the range of 85 wt% or more based on 100 wt% of the total amount of the phthalic anhydride by-product.

Preferably, the fumaric acid is used in an amount ranging from 56 parts by weight to 57 parts by weight based on 100 parts by weight of the total of the phthalic anhydride by-product.

The unsaturated polyester of the present invention is obtained by the above process for producing an unsaturated polyester. The unsaturated polyester has an acid value ranging from 31 mgKOH/g to 33 mgKOH/g and a viscosity ranging from 830 cps to less than 950 cps.

The curing composition of the present invention comprises: an unsaturated polyester which is subjected to a polycondensation reaction of a phthalic anhydride by-product with glycerin to form a prepolymer having an acid value in the range of less than 3 mgKOH/g and a viscosity in the range of 350 cps or more and 650 cps or less. And adding a fumaric acid to carry out a polycondensation reaction, wherein the phthalic anhydride by-product comprises 80% by weight or more of benzoic acid and phthalic anhydride; and styrene.

Preferably, the weight ratio of glycerol to benzoic acid in the by-product of the phthalic anhydride is less than 0.85.

Preferably, the content of the benzoic acid is in the range of 85 wt% or more based on 100 wt% of the total amount of the phthalic anhydride by-product.

Preferably, the fumaric acid is used in an amount ranging from 56 parts by weight to 57 parts by weight based on 100 parts by weight of the total of the phthalic anhydride by-product.

Preferably, the styrene is used in an amount ranging from 30% by weight to 40% by weight based on 100% by weight of the total of the curing composition.

The curing composition has an acid value ranging from 15 mgKOH/g to 20 mgKOH/g and a viscosity ranging from 450 cps to 600 cps.

The curing composition of the present invention may be added to a reagent component containing a hardening accelerator and a hardener and heat-treated to form a cured product. The cured product preferably has good mechanical properties (e.g., elongation, tensile strength or flexural strength) and thermal properties (e.g., high heat distortion temperature). The hardener may be used singly or in combination, and the hardener is, for example but not limited to, methyl ethyl ketone peroxide. The hardening accelerator may be used singly or in combination, and the hardening accelerator is, for example but not limited to, Cobalt isooctylate or cobalt naphthenate.

<Example>

<Example 1> Preparation of unsaturated polyester and curing composition

422 g of phthalic anhydride by-product (85 wt% of benzoic acid and 15 wt% of phthalic anhydride) and 275 g of glycerin were placed in a 2 liter four-necked flask, and the temperature was raised to 160 ° C to 165 ° C, and the reaction was carried out at a constant temperature for 1.5 hours. Further, the temperature was raised to 225 ° C, and the reaction was carried out at a constant temperature for 5 hours to obtain a prepolymer having an acid value of 1.1 mgKOH/g and a viscosity of 358 cps (measured at 50 ° C). Next, the temperature is lowered to below 155 ° C, 220 g of fumaric acid is added for esterification, and the temperature is raised to 160 to 165 ° C, and the reaction is carried out at a constant temperature for 1.5 hours, and then, the temperature is raised to 210 ° C, and the reaction is kept at a constant temperature. An unsaturated polyester having an acid value of 32.8 mgKOH/g and a viscosity of 833 cps (measured at 130 ° C) was obtained in an hour. Next, the temperature was lowered to below 100 ° C, and then 510 g of styrene was added and stirred to obtain a curing composition, and the acid value was measured to be 19.5 mgKOH/g and the viscosity was 480 cps (measured at 25 ° C). Got).

<Example 2>

422 g of phthalic anhydride by-product (85 wt% of benzoic acid and 15 wt% of phthalic anhydride) and 285 g of glycerin were placed in a 2 liter four-necked flask, and the temperature was raised to 160 ° C to 165 ° C, and the reaction was carried out at a constant temperature for 1.5 hours. Further, the temperature was raised to 225 ° C, and the reaction was carried out at a constant temperature for 5 hours to obtain a prepolymer having an acid value of 1.8 mgKOH/g and a viscosity of 451 cps (measured at 50 ° C). Then, lower the temperature to below 155 ° C, add 240 grams of fumaric acid for esterification, and raise the temperature to 160 to 165 ° C, and the constant temperature reaction 1.5 small Thereafter, the temperature was further raised to 210 ° C, and the reaction was carried out at a constant temperature for 9 hours to obtain an unsaturated polyester having an acid value of 32.6 mgKOH/g and a viscosity of 855 cps (measured at 130 ° C). Next, the temperature was lowered to below 100 ° C, and then 545 g of styrene was added and stirred to obtain a curing composition, and the acid value was 15.2 mgKOH/g and the viscosity was 580 cps (measured at 25 ° C). Got).

<Comparative Example 1>

422 g of phthalic anhydride by-product (85 wt% of benzoic acid and 15 wt% of phthalic anhydride) and 305 g of glycerin were placed in a 2 liter four-necked flask, and the temperature was raised to 160 ° C to 165 ° C, and the reaction was kept at a constant temperature for 1.5 hours. Further, the temperature was raised to 225 ° C, and the reaction was carried out at a constant temperature for 5 hours to obtain a prepolymer having an acid value of 3.5 mgKOH/g and a viscosity of 1,005 cps (measured at 50 ° C). Next, the temperature was lowered to 155 ° C or lower, and 278 g of fumaric acid was added for esterification, and the temperature was raised to 160 to 165 ° C, and the reaction was carried out at a constant temperature for 1.5 hours, and then, the temperature was further raised to 210 ° C, and the reaction was kept at a constant temperature of 9 An unsaturated polyester having an acid value of 31 mgKOH/g and a viscosity of 950 cps (measured at 130 ° C) was obtained in an hour. Next, the temperature was lowered to 100 ° C or less, and then 581 g of styrene was added and stirred to obtain a curing composition, and the acid value was measured to be 14 mgKOH/g and the viscosity was 650 cps (measured at 25 ° C). ).

<Application example>

<Application Example 1>

To 100 g of the curing composition of Example 1, 0.3 g of a 6 wt% cobalt octoate hardening accelerator was added (label: solid; type) No.: L-24) and 1 ml of methyl ethyl ketone peroxide hardener (label: AkzoNobel; model: HBO 50), filled with sufficient agitation, and then cured at 25 ° C for 24 hours, then at 70 ° C Bake for 12 hours.

<Application Example 2>

To 100 g of the curing composition of Example 2, 0.3 g of a 6 wt% cobalt octoate hardening accelerator (label: solid addition; model: L-24) and 1 ml of methyl ethyl ketone peroxide hardener were added. (label: AkzoNobel; model: HBO 50), after thorough stirring and dispersion, the mold is filled, and cured at 25 ° C for 24 hours, and then baked at 70 ° C for 12 hours.

<Comparative Application Example 1>

To 100 g of the curing composition of Comparative Example 1, 0.3 g of a 6 wt% cobalt octoate hardening accelerator (label: solid addition; model: L-24) and 1 ml of methyl ethyl ketone peroxide hardener were added. (label: AkzoNobel; model: HBO 50), after thorough stirring and dispersion, the mold is filled, and cured at 25 ° C for 24 hours, and then baked at 70 ° C for 12 hours.

<evaluation item>

Viscosity measurement: The prepolymer, unsaturated polyester, and curing composition of Examples 1 to 2 and Comparative Example 1 were subjected to the methods of ASTM D-2398-80 at 50 ° C, 130 ° C, and 25 ° C, respectively. Measurement, unit: cps.

Acid value measurement: Pre-takements in Examples 1 to 2 and Comparative Example 1 The polymer, the unsaturated polyester, and the curing composition were measured in accordance with the method of ASTM D-1639-83, and the unit was mgKOH/g.

Heat distortion temperature measurement: The cured products of Application Examples 1 to 2 and Comparative Application Example 1 were respectively cut into strips, and then measured according to the ISO / R75 method, respectively, in units of ° C.

Tensile strength and tensile modulus measurement: The cured products of Application Examples 1 to 2 and Comparative Application Example 1 were cut into strips, respectively, and then measured according to the ISO/R527 method, respectively, in units of MPa.

Elongation at break: The cured products of Application Examples 1 to 2 and Comparative Application Example 1 were cut into strips, respectively, and then measured according to the ISO/R527 method, respectively, in units of %.

Flexural strength and flexural modulus measurement: The cured products of Application Examples 1 to 2 and Comparative Application Example 1 were cut into strips, respectively, and then measured according to the ISO/R178 method, respectively, in units of MPa.

Storage stability measurement: The curing compositions of Examples 1 to 2 and Comparative Example 1 were placed in a constant temperature oven at 80 ° C, and the time required for the gel to flow was observed. The time required for the gel to be greater than 24 hours is acceptable.

From the experimental data of Table 1, it is known that the viscosity of the prepolymer formed is 358 cps and 451 cps, indicating that no gelation occurs, and no gel of the network structure is generated, so the reaction with fumaric acid is continued. The unsaturated polyester formed is not affected by the gel, so that the compatibility with styrene is deteriorated, so that the unsaturated polyester obtained by the present invention is combined with the curing composition formed by styrene. The cured product formed by the heat treatment of the hardener and the hardening accelerator has good elongation, tensile strength and bending strength, and has a high heat distortion temperature.

It can be seen from Comparative Example 1 that the high viscosity of the formed prepolymer indicates that a gel phenomenon occurs, and a gel having a large number of network structures is generated, and therefore, the unsaturated polyester formed by the reaction with fumaric acid is continued. Due to the presence of the gel of the network structure, the compatibility of the unsaturated polyester with styrene is deteriorated, resulting in poor dispersibility, which in turn makes the unsaturated polyester react poorly with styrene, and is not easily condensed. Glue and cure.

In summary, the method for preparing an unsaturated polyester of the present invention is to completely use glycerin, and in the process of preparing an unsaturated polyester, reacting benzoic acid with glycerin to reduce the average functionality to less than three, and then, The reaction of phthalic anhydride or fumaric acid can reduce the gelation phenomenon during the reaction, thereby avoiding the deterioration of fluidity, and the reaction is not easy to carry out and operate, so the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

Claims (10)

A method for preparing an unsaturated polyester, comprising the steps of: providing a polycondensation reaction of a phthalic anhydride by-product with glycerin to form a prepolymer having an acid value in the range of less than 3 mgKOH/g and a viscosity ranging from 350 cps to 650 cps, followed by adding a reversed The enedic acid is formed by a polycondensation reaction, wherein the phthalic anhydride by-product comprises 80% by weight or more of benzoic acid and phthalic anhydride. The method for producing an unsaturated polyester according to claim 1, wherein a weight ratio of the glycerin to the benzoic acid in the phthalic anhydride by-product is in a range of less than 0.85. The method for producing an unsaturated polyester according to claim 1, wherein the content of the benzoic acid is 85 wt% or more based on 100 wt% of the total amount of the phthalic anhydride by-product. The method for producing an unsaturated polyester according to claim 1, wherein the fumaric acid is used in an amount ranging from 56 parts by weight to 57 parts by weight based on 100 parts by total of the total of the phthalic anhydride by-product. An unsaturated polyester obtained by the method for producing an unsaturated polyester according to any one of claims 1 to 4. A curing composition comprising: an unsaturated polyester which is subjected to a polycondensation reaction of a phthalic anhydride by-product with glycerin to form a prepolymer having an acid value of less than 3 mgKOH/g and a viscosity ranging from 350 cps to 650 cps, followed by addition of a counter-polymer The butyric acid is formed by a polycondensation reaction, wherein the phthalic anhydride by-product comprises 80% by weight or more of benzoic acid and phthalic anhydride; Styrene. The curing composition according to claim 6, wherein a weight ratio of the glycerin to the benzoic acid in the phthalic anhydride by-product is in a range of less than 0.85. The curing composition according to claim 6, wherein the content of the benzoic acid is 85 wt% or more based on 100 wt% of the total amount of the phthalic anhydride by-product. The curing composition according to claim 6, wherein the fumaric acid is used in an amount ranging from 56 parts by weight to 57 parts by weight based on 100 parts by weight of the total of the phthalic anhydride by-product. The curing composition according to claim 6, wherein the styrene is used in an amount ranging from 30% by weight to 40% by weight based on 100% by weight of the total of the curing composition.