KR20120076150A - Polyester resin containing polycarbonatediol having excellent suppleness, and its preparation - Google Patents

Abstract

PURPOSE: A polycarbonatediol-containing polyester resin is provided to have excellent flexibility and moldability, and to reduce the used amount of solvent for reducing viscosity because of low viscosity relative with existing polyester resin. CONSTITUTION: A manufacturing method of a polycarbonatediol-containing polyester resin comprises: a step of ester coupling reaction to the dicarboxylic acid compound, and dihydroxy compound to equivalent ratio of 1:0.7-1:0.9; and a step of adding 15-50 weight% of polycarbonate diol to the product. A polyester resin containing polycarbonate diol manufactured by the manufacturing method has weight average molecular weight of 3,000-5,000, and is in chemical formula 1. In chemical formula 1, n is a positive integer.

Description

Polycarbonate diol-containing polyester resin with excellent flexibility and manufacturing method thereof {POLYESTER RESIN CONTAINING POLYCARBONATEDIOL HAVING EXCELLENT SUPPLENESS, AND ITS PREPARATION}

The present invention relates to a polyester resin and a method for manufacturing the same, and to a polyester resin used in various industrial paints and coatings that require flexibility and formability, and a method for producing the same.

Polyester resin compositions are widely used in construction and industrial resins, and are widely used in automotive interior paints such as primers, intermediate and top coats, such as automobile air cleaners, oil filters, wheels, and bumpers. When polyester is used in various industrial interior materials or paints, the physical properties required include coating durability, scratch resistance, chipping resistance, acid resistance, and flexibility.

Durability and scratch resistance means resistance to scratches on the surface of the coating film, and the chipping resistance means durability against coating damage that the film is peeled off by external impact or reaches the steel sheet. The acid resistance is due to the effects of wild bird droppings or acid rain due to the recent severe air pollution, the surface of the coating film is damaged, stains and irregularities are often generated on the surface of the coating, which means resistance to this. Flexibility means the property of improving the moldability of a coating film by appropriate paint viscosity.

Accordingly, research for improving the quality of the polyester resins used in industrial interior materials and various paints has been steadily progressed.

As a related art relating to a method for producing a polyester resin for coating, Korean Patent Application No. 1991-18269 is known for a method for producing a polyester resin for coating by modifying two kinds of polyesters with aliphatic diisocyanate. If it is used as an industrial paint has the advantage of excellent cold resistance adhesion. However, when it is used as an industrial paint, the adhesion is improved, but there is a problem that the hardness and smoothness worsens.

In addition, Korean Patent No. 456970 is known for a coating composition using a urethane-modified polyester resin. However, in this case, the durability of the coating film is reduced, and it is still necessary to use a solvent for viscosity adjustment in order to adjust the viscosity of the paint.

Existing polyester resins as described above have the disadvantage of low flexibility and formability due to the limitation of molecular structure and chain length of the dihydroxy compound and the dicarboxylic acid compound as a basic raw material, and the high viscosity of the synthesized resin In addition, there was a non-environmental problem in that a viscosity adjusting solvent should be used.

An object of the present invention is to provide a polycarbonate diol-containing polyester resin containing a polycarbonate diol in the polyester resin is improved flexibility and moldability.

According to a preferred embodiment of the present invention to solve the above problems, the step of ester-bonding the dicarboxylic acid compound and the dihydroxy compound in 1: 0.7 to 1: 0.9 equivalent ratio; And it provides a method for producing a polyester resin containing a polycarbonate diol comprising the step of adding 15 to 50% by weight of the polycarbonate diol to the product of the reaction.

According to another suitable embodiment of the present invention, the ester coupling reaction is characterized in that it goes through a two-step temperature increase process in the 150 ~ 200 ℃ section.

According to another suitable embodiment of the present invention, there is provided a polyester resin containing a polycarbonate diol according to the above production method having a number average molecular weight of 3,000 to 5,000 and the following formula.

The polycarbonate diol-containing polyester resin of the present invention exhibits superior properties in flexibility and formability than conventional polyester resins. Through this, it can be usefully used as automotive coatings and various industrial coatings that require flexibility. In addition, since the viscosity is lower than the same molecular weight of the existing polyester resin can reduce the amount of solvent used for viscosity dilution purpose can exhibit an environmentally friendly effect.

Polycarbonate diol is a compound containing a carbonate structure and has excellent physical properties such as flexibility and surface hardness and durability, and is mainly used as a raw material for high-quality polyurethane resins. It has a hydroxyl group at both ends of the molecular chain and can react with the dicarboxylic acid compound to produce an ester bond, which is applicable to polyester resins. In addition, unlike the basic raw materials of the conventional polyester resin has a long chain structure in the molecular chain can be expected excellent properties in terms of flexibility.

In order to provide a polycarbonate diol-containing polyester resin with improved flexibility and formability, the present invention is primarily to synthesize a polyester resin composed of carboxylic acid at both ends, and secondly to change the temperature conditions to polycarbonate diol To further add to prepare a polyester resin containing a polycarbonate diol.

The present invention comprises the steps of ester-bonding the dicarboxylic acid compound and the dihydroxy compound in 1: 0.7 to 1: 0.9 equivalent ratio; And it provides a method for producing a polyester resin containing a polycarbonate diol comprising the step of adding 15 to 50% by weight of the polycarbonate diol to the product of the reaction.

When the equivalent weight of the dihydroxy compound compared to the dicarboxylic acid compound is less than 0.7, the ester coupling reaction does not sufficiently occur. When the equivalent weight of the dihydroxy compound is greater than 0.9, the chain structure in the polyester molecule is reduced, and the elongation of the resin is lowered.

As the dicarboxylic acid compound constituting the polyester resin of the present invention, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenylcarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclo At least one compound selected from the group consisting of dicarboxylic acids such as hexanedicarboxylic acid, adipic acid and sebacic acid, alkyl, alkoxy and haloken-substituted derivatives thereof, and ester forming derivatives such as respective dimethyl esters; Can be used.

Examples of the dihydroxy compound constituting the polyester resin of the present invention include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, hydroquinone, resorcinol, hydroxyphenyl, naphthalenediol, dihydroxydiphenyl ether, and cyclohexanediol. , Dihydroxy compounds such as 2,2-bis (4-hydroxyphenyl) propane, polycarbonatediol and diethoxylated bisphenol A, polyoxyalkylene glycols and alkyl, alkoxy or halogen-substituted derivatives thereof One or more compounds selected from can be used.

In addition, polyesters having a branched or crosslinkable structure made using a small amount of trifunctional or higher monomers may also be used in the present invention, the trifunctional monomers being for example trimellitic acid, trimesic acid and pyromelli Triacid, pentaerythritol, trimethylolpropane and the like.

The content of the polycarbonate diol may be adjusted to 15 to 50% by weight based on the total weight to prepare a polycarbonate diol-containing polyester resin having various molecular weights. The content of polycarbonate diol is preferably 15 to 50% by weight based on the total weight, more preferably 25 to 35% by weight relative to the total weight. When the polycarbonate diol is less than 15% by weight, the effect of improving the elongation is small, and when it is more than 50% by weight, the tensile strength is lowered.

In addition, the present invention is characterized in that the ester coupling reaction is subjected to a two-step temperature rising process in the 150 ~ 200 ℃ section. Since the pyrolysis temperature of the polycarbonate diol starts at 220 ° C. or more, the compound having much of the dicarboxyl group is reacted at a high temperature, and when the reaction is stabilized, the polycarbonate diol is introduced by lowering the temperature. Thereafter, the temperature was raised to 180 ° C. in a step temperature raising method for a stable reaction, and the reaction was terminated at a point of 5 or less.

A four-necked flask of 500 mL was attached with a thermometer, condenser, stirrer and heater. Phthalic anhydride and isophthalic acid were used as the dicarboxylic acid compound, and ethylene glycol, trimethylol propane, 1,6 hexanediol, and polycarbonate diol were used as the dihydroxy compound. Then, the temperature is raised to about 150 ° C. under a nitrogen atmosphere, and the temperature is increased to 200 ° C. in a step to carry out the polymerization reaction of the dicarboxylic acid compound and the dihydroxy compound. After removing the condensed water produced in the reaction, the reaction temperature was lowered to 100 ° C and then polycarbonate diol was added, and the temperature was raised to 180 ° C step to perform the ester bond reaction. The reaction progress was observed by measuring the acid value using 0.1 N KOH solution. When the acid value of the composite drops to 5 or less, the reaction is terminated to obtain a polycarbonate diol-containing polyester resin having a solid content of 100%.

The polymerization reaction temperature of the ester bond is condensed water is generated as the condensation reaction of the carboxyl group and the hydroxyl group proceeds at 150 ° C or higher. When the reaction temperature is lower than 150 ℃, the reaction does not occur smoothly. Especially when using a substance with high melting point such as terephthalic acid or isophthalic acid, the reaction must proceed at a temperature higher than the melting point of the raw material. Problems arise in terms of the stability of the polycarbonate diol which starts to decompose. Therefore, when using a raw material with a melting point of 180 ℃ or more, after preparing a primary polyester resin having a carboxyl group except for polycarbonate diol, the polycarbonate diol is added at a temperature below 180 ℃, and then contains polycarbonate diol in a second reaction. Polyester resin is prepared.

(In the above structural formula, n is a positive integer.)

The reaction scheme briefly illustrates a process for preparing a polyester resin containing a polycarbonate diol according to an embodiment of the present invention. Isophthalic acid and phthalic anhydride as dicarboxylic acid compounds were reacted at 200 ° C. using ethylene glycol, trimylol propane, 1,6 hexanediol as dihydroxy compounds, and then the temperature dropped to 180 ° C. or lower. To prepare a polyester resin.

In another aspect, the present invention provides a polyester resin containing a number average molecular weight of 3,000 to 5,000 and a polycarbonate diol according to the preparation method.

The polyester resin containing the polycarbonate diol according to the present invention has a hydroxyl group at both ends of the molecular chain to react with the dicarboxylic acid compound to generate an ester bond, unlike the basic raw materials of the conventional polyester resin molecular chain Because of its long chain structure, excellent physical properties can be expected in terms of flexibility. The polyester resin containing the polycarbonate diol according to the present invention contains a large amount of hydroxy groups and can be cured using a melamine curing agent, an isocyanate series curing agent, or the like.

Polycarbonate diol according to the present invention is a compound containing a carbonate structure, as well as excellent physical properties such as surface hardness, durability can be used as a variety of industrial interior materials and coatings, including the raw material of the advanced polyurethane resin.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the scope of the present invention is not limited by the following examples.

 ≪ Example 1 >

Preparation of polyester resin containing 15% by weight of polycarbonate diol

A four-necked flask of 500 mL was attached with a thermometer, condenser, stirrer and heater. 21% by weight of phthalic anhydride, 27% by weight of isophthalic acid as dicarboxylic acid compound, 5% by weight of ethylene glycol as dihydroxy compound, 10% by weight of trimethylol propane, 22% by weight of 1,6 hexanediol, polycarbonatediol 15 % By weight was used. Then, the temperature is raised to about 150 ° C. under a nitrogen atmosphere, and the temperature is increased to 200 ° C. in a step to carry out the polymerization reaction of the dicarboxylic acid compound and the dihydroxy compound. As a result of the reaction, a polymer having an equivalence ratio of 1: 0.9 of the dicarboxylic acid compound and the dihydroxy compound was formed, and after removing the condensation water generated in the reaction, the reaction temperature was lowered to 100 ° C. and 15 wt% of polycarbonate diol was added thereto. After that, the temperature is raised to 180 ° C. to cause ester coupling reaction. The reaction progress was observed by measuring the acid value using 0.1 N KOH solution. When the acid value of the composite drops to 5 or less, the reaction is terminated to obtain a polycarbonate diol-containing polyester resin having a solid content of 100%.

<Example 2>

Preparation of polyester resin containing 33 wt% of polycarbonate diol

A four-necked flask of 500 mL was attached with a thermometer, condenser, stirrer and heater. 17% by weight of phthalic anhydride, 22% by weight of isophthalic acid as dicarboxylic acid compound, 4% by weight of ethylene glycol as dihydroxy compound, 8% by weight of trimethylol propane, 16% by weight of 1,6 hexanediol, polycarbonatediol 33 % By weight was used. Then, the temperature is raised to about 150 ° C. under a nitrogen atmosphere, and the temperature is increased to 200 ° C. in a step to carry out the polymerization reaction of the dicarboxylic acid compound and the dihydroxy compound. As a result of the reaction, a polymer having an equivalence ratio of dicarboxylic acid compound and dihydroxy compound of 1: 0.9 was formed, and after removing the condensed water generated in the reaction, the reaction temperature was lowered to 100 ° C and 33% by weight of polycarbonate diol was added. After that, the temperature is raised to 180 ° C. to cause ester coupling reaction. The reaction progress was observed by measuring the acid value using 0.1 N KOH solution. When the acid value of the composite drops to 5 or less, the reaction is terminated to obtain a polycarbonate diol-containing polyester resin having a solid content of 100%.

<Example 3>

Preparation of polyester resin containing 46% by weight of polycarbonate diol

A four-necked flask of 500 mL was attached with a thermometer, condenser, stirrer and heater. 14% by weight of phthalic anhydride, 19% by weight of isophthalic acid as dicarboxylic acid compound, 4% by weight of ethylene glycol as dihydroxy compound, 6% by weight of trimethylol propane, 11% by weight of 1,6 hexanediol, polycarbonatediol 46 % By weight was used. Then, the temperature is raised to about 150 ° C. under a nitrogen atmosphere, and the temperature is increased to 200 ° C. in a step to carry out the polymerization reaction of the dicarboxylic acid compound and the dihydroxy compound. As a result, a polymer having an equivalence ratio of 1: 0.9 of the dicarboxylic acid compound and the dihydroxy compound was formed. After removing the condensed water generated in the reaction, the reaction temperature was lowered to 100 ° C. and 46 wt% of polycarbonate diol was added thereto. After that, the temperature is raised to 180 ° C. to cause ester coupling reaction. The reaction progress was observed by measuring the acid value using 0.1 N KOH solution. When the acid value of the composite drops below 5, the reaction is terminated to obtain a polycarbonate diol-containing polyester resin having a solid content of 100%.

&Lt; Comparative Example 1 &

Polyester resin manufacturing

A four-necked flask of 500 mL was attached with a thermometer, condenser, stirrer and heater. 23 weight% of phthalic anhydride, 31 weight% of isophthalic acid were used for the dicarboxylic acid compound, 7 weight% of ethylene glycol, 11 weight% of trimethylol propane, and 28 weight% of 1,6 hexanediol were used for the dihydroxy compound. Then, the temperature is raised to about 150 ° C. under a nitrogen atmosphere, and the temperature is increased to 200 ° C. in a step to carry out the polymerization reaction of the dicarboxylic acid compound and the dihydroxy compound. The reaction progress was observed by measuring the acid value using 0.1 N KOH solution. When the acid value of the compound falls below 5, the reaction is terminated to obtain a polyester resin having a solid content of 100%.

Evaluation of Physical Properties of Cured Coating Film

After the cured coating film of the polycarbonate-containing polyester resin obtained in Example was formed, physical properties were evaluated. Tensile strength was measured by applying the method of ASTM D 1822 in order to measure the flexibility of the cured coating film, the thickness of the cured coating film was about 300 ~ 500 ㎛, the curing agent was Cymel 303 of methylated melamine-based Cytec Co. 150 Curing was performed under curing conditions at 0 ° C. for 1 hour.

Tensile strength evaluation results are shown in Table 1 below.

OH value T _g (° C) Tensile Strength (MPa) Elongation (%) Example 1 87 42 18 38 Example 2 70 25 13 105 Example 3 57 15 4 72 Comparative Example 1 100 52 45 7

ASTM D 1822 for evaluating the flexibility in Table 1 is a method for measuring the tensile strength and elongation using a Universal Testing Machine (UTM) after producing a specimen of a rectangular shape on the cured coating film. Comparative Example 1 is a polyester resin of the same type except for polycarbonate diol in order to distinguish it from the example, and showed a high value in tensile strength, but showed a characteristic of a general polyester resin having an elongation of 10 or less. Examples 1 to 3 are properties of the cured coating film produced by adjusting the content of polycarbonate diol. As the content of polycarbonate diol increases, the glass transition temperature (T _g ) tends to decrease and the tensile strength tends to decrease, but the elongation increases. However, as can be seen from the results of Example 3, when the polycarbonate diol content is too high, the tensile strength reduction ratio is increased and the elongation is not increased a lot, so the polycarbonate diol content of about 33% by weight in Example 2 It was confirmed that the polyester resin of was the most excellent.

Claims (3)

Ester-bonding the dicarboxylic acid compound and the dihydroxy compound at a ratio of 1: 0.7 to 1: 0.9 equivalents; And
Method for producing a polyester resin containing a polycarbonate diol comprising the step of adding 15 to 50% by weight of the polycarbonate diol to the product of the reaction. The method according to claim 1, wherein the ester coupling reaction is characterized in that it goes through a two-step temperature increase process in the 150 ~ 200 ℃ section. A polyester resin containing a polycarbonate diol according to claim 1 having a number average molecular weight of 3,000 to 5,000.

(n is a positive integer)