JP2013209433A - Method for producing polyester resin aqueous dispersion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for easily producing a polyester resin aqueous dispersion, which is excellent in various characteristics when formed into a resin film, without using any special machine while greatly reducing defective dispersion during production or filtration clogging in a production system.SOLUTION: In a method for producing a polyester resin aqueous dispersion: a specific polyester resin is mixed to an aqueous medium along with an organic solvent and ammonia without using any surfactant, and subsequently, an agitation process (I) and an agitation process (II) are carried out in this order. In the agitation process (I), dispersion efficiency of the polyester resin becomes ≥80% by performing agitation for ≥30 minutes at a temperature not lower than a temperature found by subtracting 10°C from a glass transition temperature of the polyester resin and not higher than the glass transition temperature. In the agitation process (II), dispersion efficiency of the polyester resin becomes ≥97% by performing agitation for ≥60 minutes at a temperature not lower than a temperature found by adding 10°C to the glass transition temperature of the polyester resin. In the agitation processes (I) and (II), the dispersion efficiency means a mass ratio of the polyester resin actually dispersed in the aqueous dispersion to the used polyester resin.

Description

  The present invention relates to a method for producing an aqueous polyester resin dispersion.

  Conventionally, a polyester resin has been widely used as a resin for forming a film. The polyester resin is excellent in processability when formed into a film, resistance to chemicals and alcohol (chemical resistance, alcohol resistance) and weather resistance. At the same time, the polyester resin adheres to various substrates such as polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), molded articles and films made of vinyl chloride, and metal foils made of various metals. Also excellent in properties. For this reason, in applications such as paints, inks, adhesives or coating agents for such a substrate, a polyester resin dissolved in an organic solvent is very often used.

  In recent years, the use of organic solvents tends to be suppressed for reasons such as environmental protection, regulation of dangerous goods by the Fire Service Act, or improvement of the workplace environment. Therefore, in the above-mentioned applications, there is a strong demand for the use of an aqueous polyester resin dispersion in which a polyester resin is not dissolved in an organic solvent but is finely dispersed in an aqueous medium. ing.

  As such a polyester resin aqueous dispersion, for example, a polyester resin aqueous dispersion in which a carboxyl group of a polyester resin is neutralized with a basic compound and dispersed in an aqueous medium has been proposed (Patent Documents 1 and 2). 2). Further, Patent Documents 1 and 2 disclose that by using such an aqueous dispersion, a resin film having excellent performance such as processability, water resistance, chemical resistance and alcohol resistance can be formed. ing. In particular, in the case of a polyester resin aqueous dispersion in which a polyester resin in which terephthalic acid or isophthalic acid is used as an acid component is dispersed, the hardness, water resistance, solvent resistance, workability, etc. when the resin film is formed It is known that the industrial utility value is high in applications such as paints, coating agents and adhesives.

International Publication No. 2004/037924 Pamphlet JP 2006-182951 A

  In general, when a resin film is produced from an aqueous polyester resin dispersion, the organic resin used in the aqueous polyester resin dispersion is used to minimize the residual amount of additives such as organic solvents and dispersion aids in the resin film. It is preferable that the solvent or the basic compound has a lower boiling point. By using an organic solvent or basic compound having a lower boiling point, the organic solvent or basic compound easily volatilizes when the aqueous dispersion is heated and dried during the formation of the resin film. These remaining amounts are small. Examples of the basic compound having a lower boiling point include ammonia. However, in the production of the aqueous polyester resin dispersions described in Patent Documents 1 and 2, when ammonia is used as the basic compound, there are many undispersed materials (for example, aggregates, precipitates, or precipitates of polyester resin). There is a problem that the clogging occurs in the production system.

  In view of such a situation, the problem of the present invention is that a polyester resin aqueous dispersion that is excellent in various properties when made into a resin film, even when ammonia is used as a basic compound, poor dispersion during production Another object of the present invention is to provide a method for producing easily without using a special machine while significantly reducing clogging in a production system.

The present inventor has reached the present invention as a result of intensive studies to solve the above problems.
That is, the gist of the present invention is as follows.
(1) A surfactant is used for a polyester resin containing an acid component containing 60 mol% or more of terephthalic acid and an alcohol component containing 40 mol% or more of ethylene glycol and having an acid value of 4 to 40 mgKOH / g. A method for producing an aqueous polyester resin dispersion comprising mixing an organic solvent and ammonia together with an aqueous medium and then performing the following stirring step (I) and stirring step (II) in this order.
Stirring step (I) (Glass transition temperature of polyester resin −10) Step of stirring polyester resin at a dispersion efficiency of 80% or more by stirring for 30 minutes or more at a temperature not lower than (glass transition temperature) ° C.
Stirring Step (II) (Glass Transition Temperature of Polyester Resin +10) A step of stirring the polyester resin at a dispersion efficiency of 97% or more by stirring at a temperature of 60 ° C. or higher.
In the stirring step (I) and the stirring step (II), the dispersion efficiency of the polyester resin is the ratio of the mass of the polyester resin actually dispersed in the aqueous dispersion to the mass of the polyester resin used. It is shown.

(2) The method for producing a polyester resin aqueous dispersion according to (1), wherein in the stirring step (I), stirring is performed at a peripheral speed of the stirring blade of 0.2 to 2.0 m / s.

(3) The method for producing an aqueous polyester resin dispersion according to (1) or (2), wherein in the stirring step (II), stirring is performed at a peripheral speed of the stirring blade of 0.1 to 1.5 m / s. .

(4) An aqueous polyester resin dispersion produced by the production method of any one of (1) to (3).

(5) A resin film formed from the aqueous polyester resin dispersion of (4).

  According to the production method of the present invention, by specifying the acid value and composition of the polyester resin used, the storage stability, the film forming property when the resin film is formed, and the water resistance when the resin film is formed A polyester resin aqueous dispersion having excellent properties, alcohol resistance, chemical resistance and flex resistance can be produced. In addition, by providing a two-step stirring process and controlling the stirring temperature and stirring time in these stirring processes to a specific range, a polyester resin dispersion having excellent characteristics as described above can be converted into ammonia as a basic compound. Even in the case of using, it is possible to manufacture easily without using a special machine while significantly reducing the dispersion failure at the time of manufacture and clogging in the production system.

Hereinafter, the present invention will be described in detail.
The method for producing a polyester resin aqueous dispersion of the present invention (hereinafter sometimes referred to simply as “aqueous dispersion”) contains an acid component containing 60 mol% or more of terephthalic acid and 40 mol% or more of ethylene glycol. A polyester resin containing an alcohol component and having an acid value of 4 to 40 mg KOH / g is mixed in an aqueous medium together with an organic solvent and ammonia without using a surfactant, and then the following stirring step (I) and stirring step ( II) is performed in this order.
Stirring step (I) (Glass transition temperature of polyester resin −10) Step of stirring polyester resin at a dispersion efficiency of 80% or more by stirring for 30 minutes or more at a temperature not lower than (glass transition temperature) ° C.
Stirring Step (II) (Glass Transition Temperature of Polyester Resin +10) A step of stirring the polyester resin at a dispersion efficiency of 97% or more by stirring at a temperature of 60 ° C. or higher.

  In the stirring step (I) and the stirring step (II), the dispersion efficiency of the polyester resin is an indicator of the dispersibility of the polyester resin in the aqueous dispersion. In the present invention, the higher the dispersion efficiency, the lower the non-dispersed polyester resin (polyester resin precipitate, aggregate or precipitate). A method for obtaining the dispersion efficiency will be described later.

  In the manufacturing method of the polyester resin aqueous dispersion of the present invention, the stirring step (I) and the stirring step (II) have two stages of stirring steps, and the stirring temperature and stirring time in these stirring steps are set. By simultaneously controlling to a specific range, even when ammonia is used as the basic compound, it effectively suppresses the occurrence of undispersed polyester resin in the resulting aqueous dispersion, and the system during production The remarkable effect that the filtration clogging inside can be prevented is exhibited.

  First, the polyester resin used in the production method of the present invention will be described. The polyester resin contains an acid component and an alcohol component as constituent components.

  In the acid component constituting the polyester resin, it is necessary to contain 60 mol% or more of terephthalic acid in all acid components, preferably 70 mol% or more, more preferably 80 mol% or more. More preferably, the content is 90 mol% or more. In the present invention, by using a polyester resin containing terephthalic acid in the above range, an aqueous polyester resin dispersion excellent in bending resistance and alcohol resistance in the case of a resin film can be produced. That is, when a polyester resin having a terephthalic acid content of less than 60 mol% is used, there is a problem that only an aqueous dispersion inferior in bending resistance and alcohol resistance when formed into a resin film is produced.

  Examples of acid components other than terephthalic acid that are copolymerized with the polyester resin include aromatic dicarboxylic acids, saturated aliphatic dicarboxylic acids, unsaturated aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and trifunctional or higher functional carboxylic acids. And polycarboxylic acids having two or more carboxyl groups.

  Examples of the aromatic dicarboxylic acid include isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 3-tert-butylisophthalic acid, and diphenic acid. Examples of the saturated aliphatic dicarboxylic acid include oxalic acid, succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, aicosane diacid, hydrogenated dimer acid, and the like. Examples of the unsaturated aliphatic dicarboxylic acid include fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, and dimer acid. Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornenedicarboxylic acid and its anhydride, tetrahydrophthalic acid and its anhydride. Thing etc. are mentioned. Trifunctional or higher carboxylic acids include trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, trimesic acid, ethylene glycol bis (anhydrotrimethyl). And glycerol tris (anhydro trimellitate), 1,2,3,4-butanetetracarboxylic acid, and the like. These acid components may be used alone or in combination of two or more.

  In the polyester resin used in the present invention, the content of the aromatic dicarboxylic acid component having a sulfonate group in the total acid component is preferably less than 1 mol%, and the aromatic having a sulfonate group More preferably, it does not contain any dicarboxylic acid component. If the aromatic dicarboxylic acid component having a sulfonate group is contained in an amount of 1 mol% or more, only an aqueous polyester resin dispersion that is remarkably inferior in water resistance when formed into a resin film may be obtained.

  Generally, by blending an aromatic dicarboxylic acid having a sulfonate group with the composition of the polyester resin, the polyester resin can be easily dispersed in an aqueous medium without using a surfactant or the like. There is an advantage that you can. However, on the other hand, if the content of the aromatic dicarboxylic acid having a sulfonate group is too large, the water resistance of the polyester resin may be impaired. As a result, since only an aqueous dispersion inferior in water resistance in the case of a resin film may be obtained, in the present invention, a polyester resin containing 1 mol% or more of an aromatic dicarboxylic acid having a sulfonate group is used. It is not preferable to use it.

  Examples of the aromatic dicarboxylic acid component having a sulfonate group include 5-sodium sulfoisophthalic acid (SIPA-Na), 5-sodium sulfoterephthalic acid (STPA-Na), and 5-potassium sulfoisophthalic acid (SIPA-K). 5-potassium sulfoterephthalic acid (STPA-K), 5-lithium sulfoisophthalic acid (SIPA-Li), 5-lithium sulfoterephthalic acid (STPA-Li), 3,5-di (carbo-β-hydroxyethoxy) Sodium benzenesulfonate (SIPG-Na), 2,5-di (carbo-β-hydroxyethoxy) sodium benzenesulfonate (STPG-Na), potassium 3,5-di (carbo-β-hydroxyethoxy) benzenesulfonate (SIPG-K), 3,5-di (carbo-β-hydroxy) Toxi) lithium benzenesulfonate (SIPG-Li), dimethyl 5-sodium sulfoisophthalate (SIMM-Na), dimethyl 5-sodium sulfoterephthalate (STPM-Na), dimethyl 5-potassium sulfoisophthalate (SIMM-K) And dimethyl 5-lithium sulfoisophthalate (SIPM-Li).

  The polyester resin used in the present invention is required to contain 40 mol% or more of ethylene glycol in all alcohol components, preferably 50 mol% or more, more preferably 60 mol% or more. More preferably, the content is 70 mol% or more. By using a polyester resin containing ethylene glycol in the above range, an aqueous dispersion having excellent chemical resistance when formed into a resin film can be produced. That is, when a polyester resin having an ethylene glycol content of less than 40 mol% is used, there is a problem that only an aqueous dispersion having inferior chemical resistance when obtained as a resin film is obtained.

  Examples of alcohol components other than ethylene glycol that are copolymerized with the polyester resin include aliphatic glycols, alicyclic glycols, ether bond-containing glycols, and trifunctional or higher functional alcohol components. Aliphatic glycols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl Examples include glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, and 2-ethyl-2-butylpropanediol. Examples of the alicyclic glycol include 1,4-cyclohexanedimethanol. Examples of the ether bond-containing glycol include diethylene glycol, triethylene glycol, dipropylene glycol, polytetramethylene glycol, polyethylene glycol, and polypropylene glycol. Examples of the tri- or higher functional alcohol component include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. As the alcohol component, in addition to the above, an alkylene oxide adduct of 2,2-bis [4- (hydroxyethoxy) phenyl] propane (bisphenol A), bis [4- (hydroxyethoxy) phenyl] sulfone (bisphenol S) ) Alkylene oxide adduct and the like. These alcohol components may be used alone or in combination of two or more.

  The polyester resin used in the production method of the present invention may be copolymerized with an aliphatic lactone or a hydroxycarboxylic acid, if necessary, within a range not impairing the characteristics of the present invention. Examples of the aliphatic lactone include ε-caprolactone, δ-valerolactone, and γ-valerolactone. Examples of the hydroxycarboxylic acid include lactic acid, β-hydroxybutyric acid, p-hydroxybenzoic acid, an ethylene oxide adduct of 4-hydroxyphenyl stearic acid, and the like. The copolymerization amount of the aliphatic lactone or hydroxycarboxylic acid in the polyester resin is preferably 10 mol% or less in all the constituent components from the viewpoint of not impairing the balance of the properties of each resin film, and 5 mol% or less. It is more preferable that the amount be 1 mol% or less.

  The polyester resin used in the production method of the present invention may be copolymerized with a monocarboxylic acid and / or a monoalcohol, if necessary, within a range not impairing the characteristics of the present invention. The copolymerization ratio of the monocarboxylic acid or monoalcohol is preferably less than 1 mol%, more preferably less than 0.1 mol%, of the acid component or alcohol component constituting the polyester resin. It is particularly preferred that it is mol%. When the copolymerization ratio of these components is 1 mol% or more, the elongation of the molecular chain may be inhibited during the production of the polyester resin described later, and the desired molecular weight cannot be obtained without the polycondensation of the polyester resin proceeding. End up. As a result, an aqueous dispersion in which such a polyester resin is dispersed may be inferior in film forming property when formed into a resin film.

  Examples of the monocarboxylic acid include benzoic acid, phenylacetic acid, lauric acid, palmitic acid, stearic acid, oleic acid and the like. Examples of the monoalcohol include cetyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, octyl alcohol, stearyl alcohol, and the like.

  The acid value of the polyester resin used in the production method of the present invention needs to be 4 to 40 mgKOH / g from the viewpoint of improving the dispersibility and long-term storage stability when the aqueous dispersion is used, It is preferably 6 to 30 mgKOH / g, more preferably 8 to 30 mgKOH / g, and even more preferably 8 to 25 mgKOH / g. If the acid value of the polyester resin used is less than 4 mgKOH / g, it becomes difficult to disperse the polyester resin in an aqueous medium, and even if it can be dispersed, it is difficult to obtain a uniform aqueous dispersion, which improves storage stability. It will be inferior. On the other hand, when the acid value of the polyester resin used exceeds 40 mgKOH / g, there is a problem that only an aqueous dispersion inferior in water resistance, chemical resistance and flex resistance can be obtained when a resin film is formed. . In order to control the acid value of the polyester resin within the above range, a method of depolymerizing the polyester obtained by polycondensation may be employed.

  The glass transition temperature of the polyester resin used in the production method of the present invention is preferably −50 to 100 ° C., more preferably 0 to 100 ° C., and further preferably 40 to 100 ° C. If the glass transition temperature is less than −50 ° C., the resulting polyester resin may be inferior in heat resistance. On the other hand, when it exceeds 100 ° C., it may be difficult to disperse the obtained polyester resin in an aqueous medium. In order to control the glass transition temperature of the polyester resin within the above range, a method of appropriately selecting various monomers when polymerizing the polyester may be employed.

  The number average molecular weight of the polyester resin used in the production method of the present invention is 3000 to 25000 from the viewpoint of improving the film forming property and workability when the produced aqueous dispersion is used as a resin film. Preferably, it is 3000 to 20000, more preferably 5000 to 20000, and particularly preferably 7000 to 15000. That is, when the number average molecular weight of the polyester resin is less than 3000, only an aqueous dispersion having inferior film-forming properties may be obtained when a resin film is formed. On the other hand, when the number average molecular weight exceeds 25000, the volume average particle size of the polyester resin becomes large, and the storage stability of the resulting aqueous dispersion may be inferior. In order to control the number average molecular weight within the above range, a method of depolymerizing the polyester obtained by polycondensation may be employed.

  In addition, it is preferable that the dispersity of the polyester resin used with the manufacturing method of this invention is 1.5-6, It is more preferable that it is 1.5-5, It is further more preferable that it is 2-4. . The degree of dispersion indicates a value obtained by dividing the weight average molecular weight by the number average molecular weight. The weight average molecular weight here can be obtained by a known measurement method as described later, as with the number average molecular weight.

Next, the manufacturing method of the polyester resin used by this invention is demonstrated.
That is, the polyester resin used in the present invention can be produced by a known method by combining raw material monomers as described above. As a specific example of a method for producing a polyester resin, a raw material monomer component and / or a low polymer thereof is reacted in an inert atmosphere to carry out an esterification reaction, and then a polycondensation reaction proceeds until a desired molecular weight is reached. The method etc. which obtain a polyester resin by this can be mentioned.

  The reaction temperature in the esterification reaction is preferably 180 to 260 ° C. The reaction time is preferably 2.5 to 10 hours, more preferably 4 to 6 hours.

  The reaction temperature in the polycondensation reaction is preferably 220 to 280 ° C. The polycondensation reaction may be performed under reduced pressure, and the degree of reduced pressure is preferably 130 Pa or less. If the degree of vacuum is low, the polycondensation time may be long, or the resulting polyester resin may have a low number average molecular weight. In reducing the pressure, it is preferable to gradually reduce the pressure over a period of about 60 to 180 minutes until the pressure reaches 130 Pa or less from the atmospheric pressure.

In the polycondensation reaction, a polycondensation catalyst for promoting the reaction may be used. The polycondensation catalyst is not particularly limited, and known compounds such as zinc acetate, antimony trioxide, tetra-n-butyl titanate, and n-butylhydroxyoxotin can be used. As a usage-amount of a catalyst, it is preferable to set it as 0.1-20 * 10 < ^-4 > mol with respect to 1 mol of acid components.

  In the polycondensation reaction, phosphoric acid or triethyl phosphate as a heat stabilizer can also be used. These heat stabilizers may be added simultaneously with the polycondensation catalyst, or one of them may be added first, and the other may be added later.

  In addition, following the above polycondensation reaction, a depolymerization reaction may be performed by adding the acid component and / or alcohol component in an inert atmosphere. The depolymerization is preferably performed with an acid component from the viewpoint of imparting a desired acid value to the polyester resin. Further, from the viewpoint that the number average molecular weight of the polyester resin and the acid value can be adjusted to a desired value in a balanced manner, it is more preferable to perform depolymerization using trimellitic acid and / or its anhydride among the acid components. .

  Subsequently, the polyester resin aqueous dispersion manufactured with the manufacturing method of this invention is demonstrated below. The polyester resin aqueous dispersion is obtained by dispersing a polyester resin in an aqueous medium. The aqueous dispersion may be an emulsion.

  Here, the aqueous medium refers to a medium composed of a liquid containing water, and may contain a basic compound other than an organic solvent or ammonia as long as the ratio is less than 1% by mass.

  In the production method of the present invention, the aqueous dispersion is preferably produced so that the content of the polyester resin is 5 to 50% by mass, and the aqueous dispersion is produced so as to be 15 to 40% by mass. More preferred. When the content of the polyester resin in the aqueous dispersion exceeds 50% by mass, the dispersed polyester resin tends to aggregate, and only an aqueous dispersion having poor storage stability may be obtained. On the other hand, when the content of the polyester resin in the aqueous dispersion is less than 5% by mass, when a resin film is formed from the aqueous dispersion, a large amount of aqueous polyester resin is used to obtain a film having a sufficient film thickness. The dispersion may be consumed, which is not preferable from the viewpoint of cost.

  The polyester resin aqueous dispersion produced by the production method of the present invention preferably has a pH of 6 or more, more preferably 7 or more, and even more preferably 8 or more. If the pH is less than 6, the polyester resin dispersed in the aqueous dispersion may be aggregated and a uniform aqueous dispersion may not be obtained.

  In the aqueous polyester resin dispersion produced by the production method of the present invention, the volume average particle size of the polyester resin is preferably fine particles of 10 nm or more and 400 nm or less, and 30 nm or more and 300 nm or less from the viewpoint of improving storage stability. It is more preferable that it is 50 nm or more and 200 nm or less. When the volume average particle diameter exceeds 400 nm, precipitates are generated in the aqueous dispersion, and the storage stability may be inferior. On the other hand, when the volume average particle size of the polyester resin is less than 10 nm, handling as an aqueous dispersion may be difficult.

  The type of water used as the aqueous medium is not particularly limited, and examples thereof include distilled water, ion exchange water, city water, and industrial water. Especially, it is preferable to use distilled water or ion-exchange water from a viewpoint which prevents mixing of the impurity when it is set as an aqueous dispersion.

  In the polyester resin aqueous dispersion in the present invention, an aqueous resin such as alcohol, other water-based polyester resin, water-based urethane resin, water-based olefin resin, or water-based acrylic resin may be used as long as the effects of the present invention are not impaired. Etc. may be blended.

Next, the manufacturing method of the polyester resin aqueous dispersion of this invention is demonstrated in detail.
That is, the polyester resin as described above is mixed with an organic solvent and ammonia in an aqueous medium without using a surfactant, and then the stirring step (I) and the stirring step (II) are performed in this order. It is essential. By using such a two-step stirring process for a specific time at a specific temperature, a polyester resin can be dispersed well and a stable aqueous dispersion in which generation of undispersed materials is suppressed should be used with a special apparatus. And can be obtained simply and efficiently.

  In the production method of the present invention, so-called “self-emulsification” in which the polyester resin swells and disperses by the hydrophilic action of the carboxyl anion generated by neutralizing the carboxyl group of the polyester resin with ammonia is achieved. The Therefore, it is not necessary to take a so-called “phase inversion emulsification” in which a polyester resin is dissolved in an organic solvent in advance to obtain a solution, and this solution is mixed with an aqueous medium containing ammonia to achieve dispersion. It is more advantageous as a simple manufacturing method. The “phase inversion emulsification” means that an amount of water exceeding the amount of organic solvent contained in this solution is added to the organic solvent liquid of the polyester resin, and the organic solvent liquid system is changed from the organic solvent phase to O / W. Changing to an emulsion dispersion.

  In the production method of the present invention, the method for mixing the polyester resin in an aqueous medium together with an organic solvent and ammonia is not particularly limited. For example, the polyester resin, the organic solvent and ammonia are mixed with a surfactant. It is possible to add them all together in an aqueous medium without using them and mix them while raising the temperature. When a basic compound other than ammonia is used, it is difficult for the polyester resin to be dispersed in the aqueous medium.

  In the production method of the present invention, as described above, it is necessary to use ammonia as the basic compound. Animonia has a relatively low boiling point among all basic compounds, and when forming a film using the obtained polyester resin aqueous dispersion, heating during drying can be performed at a relatively low temperature and formed. This is because it can be most preferably used because the remaining amount of the basic compound in the coated film can be reduced. In addition, by using ammonia as the basic compound, there is an advantage that the storage stability of the obtained aqueous dispersion is excellent. Here, the presence of a large amount of basic compounds in the resulting resin film impairs the water resistance, alcohol resistance, chemical resistance, and flex resistance of the film, so it is important that it easily volatilizes at low temperatures during drying. It is. For example, when the aqueous polyester resin dispersion obtained in the present invention is used, a film can be obtained by heating at 120 ° C. for 1 minute and for a short time.

  In the present invention, an ammonia aqueous solution may be used as ammonia.

  The amount of ammonia used is based on the polyester resin 100 g having an acid value of 20 mgKOH / g from the viewpoint of improving the dispersibility of the polyester resin in the aqueous dispersion produced and further improving the dispersion efficiency and long-term storage stability. Thus, it is preferable to use 0.55 to 0.73 g of ammonia (when using an aqueous solution, for example, 2.19 to 2.91 g if 25% by mass of ammonia water), 0.61 to 0.67 g (25 If it is a mass% ammonia water, it is more preferable to use 2.43 to 2.67 g). As a measure of the amount of ammonia used, if the acid value is doubled, the amount of ammonia used is preferably doubled. When the amount of ammonia used is excessive, in the stirring step (I) or the stirring step (II), a stable aqueous dispersion is obtained, for example, the liquid viscosity increases drastically or a large amount of undispersed matter is generated. May be difficult. If the amount used is too small, the polyester resin may not be sufficiently dispersed in the aqueous medium, and a uniform aqueous dispersion may not be obtained.

  When the preferred amount of ammonia is converted in terms of equivalents, it is preferably added in an amount equivalent to 1.0 to 1.3 times the acid value of the polyester resin used, and more preferably added in an amount equivalent to 1.0 to 1.2 times. preferable. If it is 1.0 times equivalent, dispersion in an aqueous medium is insufficient, and if it exceeds 1.3 times equivalent, not only is it difficult to obtain a stable aqueous dispersion, but also storage stability is lowered. There is.

  In mixing, the use of an organic solvent can facilitate the formation of an aqueous solution. However, a part or all of the organic solvent and / or ammonia can be distilled off by the solvent removal step described later.

  Examples of the organic solvent include known organic solvents such as ketone organic solvents, aromatic hydrocarbon organic solvents, ether organic solvents, halogen-containing organic solvents, alcohol organic solvents, ester organic solvents, and glycol organic solvents. Can be used.

  Examples of the ketone organic solvent include methyl ethyl ketone, acetone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, 2-hexanone, 5-methyl-2-hexanone, cyclopentanone, and cyclohexanone. Examples of the aromatic hydrocarbon-based organic solvent include toluene, xylene, benzene and the like.

  Examples of the ether organic solvent include dioxane and tetrahydrofuran. Examples of the halogen-containing organic solvent include carbon tetrachloride, trichloromethane, dichloromethane and the like. Examples of alcohol-based organic solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol, Examples include 1-ethyl-1-propanol and 2-methyl-1-butanol.

  Examples of the ester organic solvent include ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, 3-methoxybutyl acetate, and methyl propionate. Examples of glycol organic solvents include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol Examples thereof include monobutyl ether and diethylene glycol ethyl ether acetate. Further, organic solvents such as 3-methoxy-3-methylbutanol, 3-methoxybutanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol and the like can also be used. In addition, an organic solvent may be used independently or 2 or more types may be used together.

  As an organic solvent, the solubility in water at 20 ° C. is preferably 5 g / L or more, more preferably 10 g / L or more. Moreover, it is preferable that a boiling point is 150 degrees C or less. When the boiling point exceeds 150 ° C., there is a problem that a large amount of energy is wasted in order to distill the organic solvent in the solvent removal step described later. In particular, an organic solvent having a solubility of 5 g / L or more and a boiling point of 150 ° C. or less is preferable. Specific organic solvents satisfying such conditions include methyl ethyl ketone, tetrahydrofuran, ethanol, n-propanol, isopropanol, n-butanol, ethylene glycol monoethyl ether, and the like. Of these, alcohols having 2 to 4 carbon atoms are preferred, alcohols having 3 carbon atoms are more preferred, and isopropanol is particularly preferred from the viewpoint of excellent ease of dispersibility, dispersion stability, volatility, and the like.

  Further, when an organic solvent is used, an aqueous dispersion with higher dispersion efficiency and stability can be easily produced by controlling the content ratio. For example, when isopropanol is used as the organic solvent, the content ratio of isopropanol in the organic solvent is preferably 17 to 27% by mass.

  In the production method of the present invention, it is necessary not to use a surfactant. This is because when a surfactant is used, the polyester resin can be easily dispersed in an aqueous medium, but there is a problem that only an aqueous dispersion in which the water resistance when the resin film is formed is significantly reduced can be obtained. .

  Here, as a general surfactant, for example, Igepal series manufactured by Aldrich; Naroacty N-100, Naroacty N-120, Naroacty N-140 manufactured by Sanyo Kasei Co., Ltd., etc .; Sanyo Kasei Sannonic SS series such as Sannonic SS-120, Sannonic SS-90 and Sannonic SS-70 manufactured by Sanyo Chemical Co., Ltd .; Sannonic FD series such as Sannonic FD-140, Sannonic FD-100 and Sannonic FD-80 manufactured by Sanyo Chemical; Sanyo Kasei Cedran FF series such as Cedran FF-220, Cedran FF-210, Cedran FF-200, Cedran FF-180 manufactured by Sanyo Chemical Co., Ltd. Cedran SNP series such as Cedran SNP-112 manufactured by Sanyo Kasei Co., Ltd. PE-64, New Pole P New Paul PE series such as E-74 and New Paul PE75; Sanmorin 11 and the like.

The stirring step (I) will be described below.
The stirring step (I) is a step of setting the polyester resin dispersion efficiency to 80% or more by stirring for 30 minutes or more at a temperature of (glass transition temperature of the polyester resin−10) ° C. or more (glass transition temperature) ° C. or less. is there.

Here, the dispersion efficiency indicates the dispersibility of the polyester resin in the aqueous polyester resin dispersion, and is calculated by the following method.
First, the mass of the polyester resin charged when the aqueous polyester resin dispersion is produced is weighed, and this value is defined as W ₀ g. Next, using the mass Z ₁ g of the aqueous dispersion actually produced, the mass W _{1 of the} polyester resin dispersed in the finally obtained aqueous dispersion is calculated from the following equation.
W ₁ (g) = (Z ₁ ) × [concentration of solid content in aqueous dispersion (%) / 100]

Next, the dispersion efficiency of the aqueous polyester resin dispersion is determined by the following formula.
Dispersion efficiency (%) = (W ₁ / W ₀ ) × 100
In addition, the calculation method of solid content concentration in an aqueous dispersion is explained in full detail in an Example.

  In this invention, it has shown that the polyester resin which is not disperse | distributed to an aqueous dispersion becomes more undispersed material and precipitates, aggregates, or precipitates, so that a dispersion efficiency is a low value.

  For example, when the Tg of the polyester resin used is 50 ° C., the stirring temperature (temperature of the stirring tank) in the stirring step (I) is controlled at 40 to 50 ° C., and stirring is performed for 30 minutes or more. is there. By stirring while simultaneously controlling the stirring temperature and stirring time within this range, the polyester resin can be appropriately swollen with ammonia and / or an aqueous medium, and the dispersion efficiency at the end of the stirring step (I) is 80%. This can be done. In addition, in the subsequent stirring step (II), there is a remarkable effect that the polyester resin can be stably dispersed.

  When the stirring temperature in the stirring step (I) is less than (glass transition temperature of the polyester resin−10) ° C., the polyester resin is insufficiently swollen, while the temperature in the stirring step (I) is (glass transition temperature). When the temperature exceeds ℃, the dispersion proceeds non-uniformly, and in any case, the dispersion efficiency at the end of the stirring step (I) becomes less than 80%. As a result, the amount of undispersed material increases and an aqueous dispersion in which the polyester resin is stably dispersed cannot be obtained.

  The stirring time in the stirring step (I) needs to be 30 minutes or more, preferably 30 to 180 minutes, more preferably 30 to 120 minutes, and further preferably 30 to 90 minutes. preferable. When the stirring time is less than 30 minutes, swelling of the polyester resin by ammonia or an aqueous medium becomes insufficient, and an aqueous dispersion in which the polyester resin is stably dispersed cannot be obtained. On the other hand, if it exceeds 180 minutes, excessive energy is consumed for this purpose, which is not preferable from the viewpoint of cost and the like.

  The dispersion efficiency at the end of the stirring step (I) needs to be 80% or more, and preferably 85% or more. If the dispersion efficiency is less than 80%, the polyester resin cannot be stably dispersed in the subsequent stirring step (II), and the dispersion efficiency at the end of the stirring step (II) cannot be in a desired range. .

  The stirring step (II) will be described below. As described above, the stirring step (II) is a step of setting the dispersion efficiency of the polyester resin to 97% or more by stirring at a temperature of (polyester resin glass transition temperature + 10) ° C. or more for 60 minutes or more.

  For example, when Tg of the polyester resin to be used is 50 ° C., the stirring temperature (temperature of the stirring tank) in the stirring step (II) is controlled to 60 ° C. or higher and stirred for 60 minutes or longer. By stirring while controlling the temperature of the stirring tank and the stirring time within this range, the polyester resin is dispersed well, and the dispersion efficiency at the end of the stirring step (II) can be 97% or more. As a result, a stable aqueous dispersion in which the generation of undispersed material is suppressed can be easily and efficiently obtained without using a special apparatus.

  When the temperature in the stirring step (II) is lower than (glass transition temperature of polyester resin + 10) ° C., the dispersion of the polyester resin becomes incomplete, and a large amount of undispersed matter is generated. In addition, it is preferable that the temperature in stirring process (II) is (Tg + 10) -110 degreeC.

  When the stirring time in the stirring step (II) is less than 60 minutes, the polyester resin is not sufficiently dispersed, and an aqueous dispersion in which the polyester resin is stably dispersed cannot be obtained. The stirring time is preferably 60 to 180 minutes, and more preferably 60 to 120 minutes. When the stirring time exceeds 180 minutes, excessive energy is consumed for this purpose, which is not preferable from the viewpoint of cost and the like.

  The dispersion efficiency at the end of the stirring step (II) needs to be 97% or more, and preferably 99% or more. If the dispersion efficiency is less than 97%, the polyester resin cannot be stably dispersed in the resulting aqueous dispersion. As a result, undispersed matter is generated, and filtration clogging occurs in the production system.

  In the stirring step (I) and the stirring step (II), as a device for stirring, various stirring devices such as a homomixer can be used from the viewpoint of improving the dispersibility of the polyester resin. The choice of wings is important. That is, when the rotation radius of the stirring blade is sufficiently large with respect to the stirring vessel, the stirring efficiency can be sufficiently increased, and consequently the dispersion efficiency of the stirring step (I) and the stirring step (II) of the present invention is increased. Can be increased.

  Furthermore, as a method for stirring, the peripheral speed of the blade tip of the stirring blade is preferably 0.2 to 2.0 m / s in the stirring step (I), and 0.3 to 1.5 m / s. It is more preferable that In stirring process (II), it is preferable that it is 0.1-1.5 m / s, and it is preferable that it is 0.2-1.0 m / s. By performing stirring at such a peripheral speed, the dispersion efficiency at the end of the stirring step (I) and the stirring step (II) of the present invention can be set in the above range.

The peripheral speed is calculated from the following formula using the rotation speed n (rpm) of the stirring blade (rotation speed per minute) and the rotation radius of the stirring blade (that is, the stirring blade radius) R (mm). It is a value and is an index representing the efficiency of stirring regardless of the scale of stirring.
Peripheral speed (m / s) = 2πnR
For example, the tip of a stirring blade when stirring at a rotation speed of 30 rpm using a stirring device equipped with a stirring blade having a rotation radius of 70 mm for a cylindrical container having a capacity of 3 L (radius inside the container: 75 mm, height: 170 mm) The peripheral speed of the stirring blade is 0.21 m / s, and the peripheral speed at the tip of the stirring blade is 0.51 m / s when stirring at a rotational speed of 70 rpm.

  In the method for producing a polyester resin aqueous dispersion of the present invention, the organic solvent or ammonia may be distilled off (desolvent) after the stirring step (I) and the stirring step (II). This is because the storage stability of the aqueous dispersion may be inferior when the organic solvent or ammonia remains in the system.

  The solvent removal step can be performed by a method of distilling the aqueous medium after the dispersion step. Distillation may be carried out at normal pressure or under reduced pressure, and any apparatus can be used as long as it is equipped with a tank into which a liquid can be introduced and can be appropriately stirred.

  Moreover, in the manufacturing method of this invention, the filtration process may be provided in the back | latter stage of stirring process (I) and stirring process (II) in order to remove a foreign material etc. In the filtration step, for example, a 600-mesh stainless steel filter (filtration accuracy 25 μm, twill) may be installed, and normal pressure filtration or pressure (air pressure of about 0.2 MPa) filtration may be performed. The filtration step may be provided immediately after the stirring step (I) and the stirring step (II), or may be provided after the solvent removal step when the above-described solvent removal step is provided.

  In the polyester resin aqueous dispersion produced by the production method of the present invention, a curing agent, various additives, a compound having a protective colloid action, water, and an organic solvent are added to the polyester resin aqueous dispersion as long as the effects of the present invention are not impaired. Solvents, pigments such as titanium oxide, zinc white, and carbon black, dyes, other water-based polyester resins, water-based urethane resins, water-based olefin resins, water-based resins such as water-based acrylic resins, and the like may be blended.

  The resin film of the present invention can be formed from the aqueous polyester resin dispersion produced by the production method of the present invention. The method for forming the resin film is not particularly limited. For example, a gravure coating method, a Mayer bar coating method, a dipping method, a brush coating method, a spray coating method, a curtain flow coating method, or the like may be employed. Can do. By using these methods, the polyester resin aqueous dispersion is uniformly coated on the surface of various substrates, set as necessary near room temperature, and then subjected to a heat treatment for drying and baking, whereby the present invention is used. The resin coating can be formed in close contact with the substrate surface. Examples of the heating device used for the heat treatment include a normal hot air circulation type oven and an infrared heater.

  The heating temperature and the heating time are appropriately selected depending on the type of substrate. Especially, when economical efficiency is considered, it is preferable that it is 60-250 degreeC normally as heating temperature, It is more preferable that it is 70-230 degreeC, It is further more preferable that it is 80-200 degreeC. The heating time is usually preferably 1 second to 30 minutes, more preferably 5 seconds to 20 minutes, and further preferably 10 seconds to 10 minutes.

  The thickness of the resin coating of the present invention is appropriately selected depending on the purpose and application. Especially, it is preferable that it is 0.01-40 micrometers, it is more preferable that it is 0.1-30 micrometers, and it is further more preferable that it is 0.5-20 micrometers.

  The aqueous polyester resin dispersion produced by the production method of the present invention is excellent in storage stability. In addition, when it is formed into a resin film, it has film-forming properties, water resistance, alcohol resistance, chemical resistance and resistance. Excellent flexibility. Therefore, the obtained resin film is very useful in applications such as a packaging film that performs boil processing and retort processing, and a laminated member of a decorative film for a high-temperature and high-humidity space represented by a bathroom.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to these examples.

The evaluation method and measurement method used in the present invention are as follows.
(1) Composition of polyester resin By ¹ H-NMR analysis using a high-resolution nuclear magnetic resonance apparatus (manufactured by JEOL Ltd., “ECA500 NMR”), the composition of the polyester resin is determined from the peak intensity of each copolymer component. Asked. As analysis conditions, deuterated trifluoroacetic acid was used as a solvent, the resolution was 500 MHz, and the temperature was 25 ° C. In addition, for resins containing monomers that do not have a peak that can be assigned or quantified on the ¹ H-NMR spectrum, methanol was decomposed in a sealed tube at 230 ° C. for 3 hours, and then subjected to gas chromatogram analysis for quantitative analysis. It was.

(2) Acid value of polyester resin 0.5 g of polyester resin was dissolved in 50 ml of a mixed solvent of water and 1,4-dioxane [(water) / (1,4-dioxane) = 1/9, volume ratio] at room temperature. And used as a solution. This solution was titrated with 0.1N potassium hydroxide methanol solution using cresol red as an indicator, and the number of mg of potassium hydroxide (gKOH / g) per gram of copolyester resin consumed for neutralization was determined by acid value. It was.

(3) Glass transition temperature of polyester resin 10 mg of the polyester resin was used as a sample, and the temperature was raised using an input compensation type differential scanning calorimeter (Perkin Elmer, “Diamond DSC”, detection range: −50 ° C. to 200 ° C.). Measurements were made at a speed of 10 ° C./min. And in the obtained temperature rise curve, at the intersection of the straight line obtained by extending the low temperature side baseline to the high temperature side and the tangent line drawn at the point where the slope of the step change portion of the glass transition becomes maximum The temperature was determined and used as the glass transition temperature.

(4) Number average molecular weight and weight average molecular weight of polyester resin Using gel permeation chromatography (GPC), the polystyrene-equivalent number average molecular weight and weight average molecular weight were measured under the following conditions.
[Liquid feeding unit]: LC-10ADvp manufactured by Shimadzu Corporation
[Ultraviolet-visible spectrophotometer]: SPD-6AV manufactured by Shimadzu Corporation, detection wavelength: 254 nm
[Column]: One Shodex KF-803 and two Shodex KF-804s connected in series [Solvent]: Tetrahydrofuran [Measurement temperature]: 40 ° C.

(5) Concentration of solid content of aqueous polyester resin dispersion About 1 g of the aqueous polyester resin dispersion was weighed to obtain X ₁ g. Furthermore, the mass of the residue after drying this aqueous dispersion at 150 ° C. for 2 hours was weighed, and this was defined as Y ₁ g. And solid content concentration was calculated | required by the following formula | equation (I).
Solid content concentration (% by mass) = (Y ₁ / X ₁ ) × 100 (A)

(6) pH of aqueous polyester resin dispersion
Using a pH meter (Horiba Seisakusho "F-21") and calibrating with pH 7 and pH 9 standard buffer (Nacalai Tesque), the measurement temperature is 25 ° C and the pH of the polyester resin aqueous dispersion is measured. did.

(7) Volume average particle diameter and number average particle diameter of polyester resin in aqueous polyester resin dispersion The product was diluted with water so that the concentration of the polyester resin in the aqueous polyester resin dispersion was 0.1% by mass. On the other hand, a volume average particle diameter and a number average particle diameter of the polyester resin in the aqueous dispersion are measured using a laser diffraction particle diameter measuring apparatus [manufactured by Nikkiso Co., Ltd., “MICROTRAC UPA” (model 9340-UPA)]. did. The refractive index of the polyester resin was set to 1.57, and the density of the polyester resin was set to 1.21 g / cm ³ .

(8) Dispersion efficiency in aqueous polyester resin dispersion The mass of the polyester resin charged when the aqueous polyester resin dispersion is produced is weighed (referred to as W ₀ ), and the mass of the aqueous dispersion actually produced (Z ₁ The mass W _{1 of the} polyester resin dispersed in the obtained aqueous dispersion was calculated from the following formula (B).
W ₁ (g) = (Z ₁ ) × [Solid content concentration (%) / 100 in aqueous dispersion determined in (5) above] (b)
Subsequently, the dispersion efficiency was calculated | required by the following formula | equation (c).
Dispersion efficiency (%) = (W ₁ / W ₀ ) × 100 (c)

(9) Storage stability of aqueous polyester resin dispersion 30 g of the aqueous dispersion was sealed in a 50 mL glass sample bottle and stored at 25 ° C for 180 days. After storage, the supernatant liquid was collected from the sample bottle, the solid content concentration was measured, the ratio of the precipitated polyester resin was calculated by the following formula (d), and evaluated according to the following criteria.
Ratio of precipitated polyester resin (mass%) = [solid content concentration before storage (mass%) − solid content concentration after storage (mass%)] / [solid content concentration before storage (mass%)] (d)
(Double-circle): The ratio of the precipitated polyester resin is less than 0.1 mass%.
(Circle): The ratio of the precipitated polyester resin is 0.1 mass% or more and less than 0.5 mass%.
(Triangle | delta): The ratio of the precipitated polyester resin is 0.5 mass% or more and less than 1.0 mass%.
X: The ratio of the precipitated polyester resin is 1.0 mass% or more.

(10) Film-forming property of resin coating An aqueous dispersion is applied to a corona-treated surface of a biaxially stretched PET film (manufactured by Unitika Ltd., thickness 38 μm) on a desktop coating apparatus (Yasuda Seiki Co., Ltd., film applicator No. 542). -AB type, equipped with a bar coater). Then, the resin film whose film thickness is 1 micrometer was formed by making it dry for 1 minute in the hot air dryer set to 120 degreeC. The resin film was visually observed, and the film forming property was evaluated according to the following criteria. In addition, the film thickness of the resin film was measured in advance using a thickness meter (manufactured by Union Tool, “MICROFINE”), and after forming the resin film on the film using an aqueous dispersion, The thickness of the substrate having this resin coating was measured by the same method, and the difference was calculated.
○: Neither cracks, butts and whitening are observed.
X: Any of cracks, bumps and whitening is observed.

(11) Water Resistance of Resin Film A resin film having a thickness of 1 μm was formed on the PET film in the same manner as (10). Thereafter, it was immersed in distilled water at 60 ° C., gently pulled up after 24 hours, and air-dried. Next, the appearance of the resin coating was visually observed, and the water resistance was evaluated according to the following criteria.
○: There was no change in the appearance of the resin coating.
(Triangle | delta): The resin film surface became cloudy white.
X: The resin film was dissolved and swollen.

(12) Alcohol resistance of resin coating In the same manner as in (10) above, a resin coating having a thickness of 1 μm was formed on a PET film. Then, it was immersed in 25 degreeC isopropanol, and it pulled up gently 24 hours later, and made it air dry. Next, the appearance of the resin film was visually observed, and the alcohol resistance was evaluated according to the following criteria.
○: There was no change in the appearance of the resin coating.
(Triangle | delta): The resin film surface became cloudy white.
X: The resin film was dissolved and swollen.

(13) Chemical resistance of resin coating In the same manner as in (10) above, a resin coating having a thickness of 1 μm was formed on a PET film. Then, it was immersed in 25 degreeC hydrochloric acid aqueous solution (0.1N), and it pulled up gently 24 hours later, and made it air dry. Next, the appearance of the resin coating was visually observed, and chemical resistance was evaluated according to the following criteria.
○: No change in appearance.
X: The surface state was changed (the surface was clouded white, the resin film was dissolved, swelled, etc.).

(14) Bending resistance of resin coating The obtained aqueous dispersion was applied to a tin-free steel (0.3 mm thickness) with a desktop coating device (“Yamada Seiki Co., Ltd.,“ Film Applicator No. 542-AB type ”), Coated with a bar coater). Then, the resin film with a film thickness of 4 micrometers was formed by making it dry for 3 minutes in the hot air dryer set to 150 degreeC. Next, the tin-free steel on which the resin film was formed was cut out to 150 mm × 50 mm to obtain a test piece. The measurement was performed as follows according to JIS K5600-5-1. That is, a test piece was inserted into a film performance evaluation apparatus (“Paint film bending tester No. 514” manufactured by Yasuda Seiki Co., Ltd.) so that the resin film forming surface was on the outer side with respect to the curvature core rod, and 180 ° in 1 second. Bent. Then, the bent part was observed visually and the bending resistance was evaluated according to the following criteria. In addition, three types having different diameters were used as the curvature core rods, and the respective diameters were 10 mm, 6 mm and 1 mm. The smaller the diameter of the curvature core rod, the more severe the test, and the better the evaluation under the severe test, the better the bending resistance.
○: The resin film is not broken or peeled off, and is resistant to bending.
(Triangle | delta): A micro crack (crack less than 2 mm) is seen in a resin film.
X: The resin film is cracked and peeled off.

(15) Peripheral speed during stirring The rotation speed (rpm) and the stirring blade radius (mm) of the stirring blade during stirring were used to calculate the following speed.
Peripheral speed (m / s) = 2πnR

The polyester resin used in Examples and Comparative Examples was obtained as follows.
[Preparation example of polyester resin]
[Polyester resin A]
A mixture consisting of 2907 g of terephthalic acid (TPA), 1246 g of isophthalic acid (IPA), 1055 g of ethylene glycol (EG) and 1745 g of neopentyl glycol (NPG) was heated in an autoclave at 260 ° C. for 6 hours to carry out an esterification reaction. . The charged resin composition was TPA / IPA / EG / NPG = 70/30/68/67 (molar ratio). Next, 1.8 g of antimony trioxide (2.5 × 10 ⁻⁴ mol per mol of the acid component) and 0.3 g of phosphoric acid (1.0 × 10 ⁻⁴ mol per mol of the acid component) were added as catalysts, The system temperature was raised to 280 ° C., and the system pressure was gradually reduced to 13 Pa after 1.5 hours. Under this condition, the polycondensation reaction was continued, and after 4 hours, the system was brought to atmospheric pressure with nitrogen gas, and the temperature of the system was lowered to 265 ° C. .02 mol) was added and stirred at 265 ° C. for 2 hours to effect depolymerization. Thereafter, the system was pressurized with nitrogen gas, and the resin was discharged in a sheet form. This was sufficiently cooled to room temperature, then pulverized with a crusher, and a fraction having an opening of 1 to 6 mm was collected using a sieve to obtain a granular polyester resin A. The charge composition of the polyester resin A is shown in Table 1.

[Polyester resin B]
A mixture composed of 4153 g of terephthalic acid (TPA), 1133 g of ethylene glycol (EG) and 1614 g of neopentyl glycol (NPG) was heated in an autoclave at 260 ° C. for 6 hours to carry out an esterification reaction. The charged resin composition was TPA / EG / NPG = 100/73/62 (molar ratio). Next, 1.4 g of zinc acetate (2.5 × 10 ⁻⁴ mol per mol of acid component) was added as a catalyst, the temperature of the system was raised to 280 ° C., and the pressure of the system was gradually reduced to 1.5 It was set to 13 Pa after time. Under this condition, the polycondensation reaction was further continued, and after 3 hours, the system was brought to atmospheric pressure with nitrogen gas, the temperature of the system was lowered, and when the temperature reached 265 ° C., 96 g of trimellitic anhydride (0. 02 mol) was added and stirred at 265 ° C. for 2 hours to carry out a depolymerization reaction. Thereafter, the system was pressurized with nitrogen gas, and the resin was discharged in a sheet form. This was sufficiently cooled to room temperature, then pulverized with a crusher, and a fraction having an opening of 1 to 6 mm was collected using a sieve to obtain a granular polyester resin B. The charge composition of the polyester resin B is shown in Table 1.

[Polyester resins C to L]
Polyester resins C to L were obtained in the same manner as the polyester resin A except that the charged composition of the polyester resin and the depolymerizing agent were changed as shown in Table 1.

なお、表１および表２における略語は、以下のものを示す。
ＴＰＡ：テレフタル酸
ＩＰＡ：イソフタル酸
ＡＤＡ：アジピン酸
ＥＧ：エチレングリコール
ＮＰＡ：ネオペンチルグリコール
ＢＡＥＯ：２，２−ビス［４−（ヒドロキシエトキシ）フェニル］プロパンのエチレンオキシド付加体
ＴＭＭＡ：無水トリメリット酸
ＴＭＡ：有水トリメリット酸
ＳＩＰＡ：５−ナトリウムスルホイソフタル酸

In addition, the abbreviation in Table 1 and Table 2 shows the following.
TPA: terephthalic acid IPA: isophthalic acid ADA: adipic acid EG: ethylene glycol NPA: neopentyl glycol BAEO: ethylene oxide adduct of 2,2-bis [4- (hydroxyethoxy) phenyl] propane TMMA: trimellitic anhydride TMA: Hydrous trimellitic acid SIPA: 5-sodium sulfoisophthalic acid

  Table 2 shows the final resin compositions and characteristic values of the obtained polyester resins A to L.

[Example 1]
Polyester resin A using a jacketed cylindrical glass container with a jacket (inner volume 3 L; inner radius of 75 mm, height of 170 mm) and a stirrer (manufactured by Tokyo Science Instruments Co., Ltd., “MAZELA NZ-1200”) 300 g, 180 g of isopropanol, 7.6 g of ammonia water having a concentration of 25% by mass (corresponding to 1.05 times equivalent of ammonia to the acid value of the polyester resin), and 512 g of distilled water were each charged in a glass container. The temperature of the agitating blade (stirring rod with blades; blade diameter: 140 mm) was increased by passing hot water through the jacket while stirring at a rotation speed of 70 rpm. When the internal temperature reached 58 ° C., the temperature was raised and stirring was continued for 30 minutes. During stirring, the temperature was appropriately raised so as to keep the internal temperature at 58 to 62 ° C. The stirring up to this point is the stirring step (I).

  The following is the stirring by the stirring step (II). That is, after carrying out the stirring step (I), while continuing stirring, the temperature was raised again through hot water through the jacket, and when the temperature reached 78 ° C., the temperature was raised and stirring was continued for 120 minutes. During the stirring, the temperature was appropriately raised so as to keep the internal temperature at 78 to 82 ° C. Thereafter, cold water was passed through the jacket, and the rotation speed was lowered to 30 rpm and the mixture was cooled to 25 ° C. while stirring to obtain an aqueous polyester resin dispersion. The obtained aqueous dispersion was filtered with a 600 mesh stainless steel filter.

[Example 2]
Use of polyester resin B, and feed amount of ammonia water having a concentration of 25% by mass to 8.8 g (corresponding to 1.0 times equivalent of ammonia to the acid value of polyester resin) and distilled water to 511 g A polyester resin aqueous dispersion was obtained in the same manner as in the production method described in Example 1 with modification. In addition, the stirring temperature of stirring process (I) was 68-72 degreeC, and the stirring temperature of stirring process (II) was 84-88 degreeC.

[Example 3]
Use polyester resin C, and charge 10.5 g of ammonia water having a concentration of 25% by mass (corresponding to 1.0 times equivalent of ammonia to the acid value of polyester resin), charge of distilled water Was changed to 510 g, and an aqueous polyester resin dispersion was obtained in the same procedure as in the production method described in Example 1. In addition, the stirring temperature of stirring process (I) was 38-40 degreeC, and the stirring temperature of stirring process (II) was 63-66 degreeC.

[Example 4]
Use polyester resin D, and charge 3.0 g of ammonia water having a concentration of 25% by mass (equivalent to 1.1 times equivalent of ammonia to the acid value of polyester resin), charge of distilled water Was changed to 517 g, and an aqueous polyester resin dispersion was obtained in the same procedure as in the production method described in Example 1. In addition, the stirring temperature of stirring process (I) was 65-68 degreeC, and the stirring temperature of stirring process (II) was 81-84 degreeC.

[Example 5]
The amount of isopropanol charged was changed to 220 g and the amount of distilled water charged was changed to 472 g, and an aqueous polyester resin dispersion was obtained in the same procedure as in the production method described in Example 1. The stirring temperature in the stirring step (I) and the stirring step (II) was also the same as in Example 1.

[Example 6]
The amount of isopropanol charged was changed to 150 g and the amount of distilled water charged was changed to 542 g, and a polyester resin aqueous dispersion was obtained in the same procedure as in the production method described in Example 1. The stirring temperature in the stirring step (I) and the stirring step (II) was also the same as in Example 1.

[Example 7]
Example 1 The amount of ammonia water having a concentration of 25% by mass was changed to 9.4 g (corresponding to 1.3 times equivalent of ammonia to the acid value of the polyester resin), and the amount of distilled water was changed to 511 g. A polyester resin aqueous dispersion was obtained by the same procedure as in the production method described in 1. above. The stirring temperature in the stirring step (I) and the stirring step (II) was also the same as in Example 1.

[Example 8]
Using polyester resin I, and charging amount of ammonia water having a concentration of 25% by mass (corresponding to 1.05 times equivalent of ammonia to the acid value of polyester resin), charging amount of distilled water Was changed to 518 g, and an aqueous polyester resin dispersion was obtained in the same procedure as in the production method described in Example 1. The stirring temperature in the stirring step (I) was the same as that in Example 1.

[Example 9]
Use polyester resin J, and charge 15.3 g of ammonia water having a concentration of 25% by mass (corresponding to 1.05 times equivalent of ammonia to the acid value of the polyester resin), charge of distilled water Was changed to 505 g, and an aqueous polyester resin dispersion was obtained in the same procedure as in the production method described in Example 1. The stirring temperature in the stirring step (I) was the same as that in Example 1.

[Example 10]
A polyester resin aqueous dispersion was obtained by the same charging amount and procedure as in the production method described in Example 1 except that the polyester resin K was used. The stirring temperature in the stirring step (I) was the same as that in Example 1.

[Example 11]
Using polyester resin L, and charging amount of ammonia water having a concentration of 25% by mass to 9.6 g (corresponding to 1.05 times equivalent ammonia to the acid value of polyester resin), charging amount of distilled water Was changed to 510 g, and an aqueous polyester resin dispersion was obtained in the same procedure as in the production method described in Example 1. The stirring temperature in the stirring step (I) was the same as that in Example 1.

[Example 12]
The temperature in the stirring step (I) was 53 to 57 ° C., that is, (Tg−10) ° C., and an aqueous polyester resin dispersion was obtained by the same procedure as the production method described in Example 1. In addition, the stirring temperature of stirring process (I) was 53-57 degreeC.

[Examples 13 to 15]
A polyester resin aqueous dispersion was obtained in the same procedure as the production method described in Example 1, except that the stirring time in the stirring step (I) was changed as shown in Table 4.

[Examples 16 to 18]
A polyester resin aqueous dispersion was obtained in the same procedure as the production method described in Example 1, except that the stirring time in the stirring step (II) was changed as shown in Table 4.

[Example 19]
A stirrer having a blade diameter of 60 mm is attached to a stirrer (manufactured by Tokyo Science Instruments Co., Ltd., “MAZELA NZ-1200”). The stirring speed is 70 rpm in the stirring process (I), and the rotating speed is 30 rpm in the stirring process (II). A polyester resin aqueous dispersion was obtained in the same procedure as in the production method described in Example 1, except that stirring was performed.

[Example 20]
The same as the production method described in Example 1, except that the stirring blade used in Example 19 is used and stirring is performed at a rotational speed of 60 rpm in the stirring process (I) and at a rotational speed of 30 rpm in the stirring process (II). A polyester resin aqueous dispersion was obtained by the procedure described above.

[Comparative Example 1]
Use of polyester resin E and 7.2 g of ammonia water having a concentration of 25% by mass (corresponding to 1.0 times equivalent of ammonia to the acid value of polyester resin), distilled water Was changed to 513 g, and an aqueous polyester resin dispersion was obtained in the same procedure as in the production method described in Example 1. In addition, the stirring temperature of stirring process (I) was 55-59 degreeC, and the stirring temperature of stirring process (II) was 75-79 degreeC.

[Comparative Example 2]
Using polyester resin F, and charging amount of ammonia water having a concentration of 25% by mass to 7.3 g (corresponding to 1.05 times equivalent of ammonia to acid value of polyester resin), charging amount of distilled water Was changed to 513 g, and an aqueous polyester resin dispersion was obtained in the same procedure as in the production method described in Example 1. In addition, the stirring temperature of stirring process (I) was 50-55 degreeC, and the stirring temperature of stirring process (II) was 75-79 degreeC.

[Comparative Example 3]
Using polyester resin G, and charging amount of ammonia water having a concentration of 25% by mass (equivalent to 1.1 times equivalent of ammonia to acid value of polyester resin), charging amount of distilled water Was changed to 519 g, and a method for producing a polyester resin aqueous dispersion was performed in the same procedure as the production method described in Example 1. However, the entire polyester resin as the contents aggregated during the reaction, and an aqueous dispersion could not be obtained. In addition, the stirring temperature of stirring process (I) was 58-62 degreeC, and the stirring temperature of stirring process (II) was 78-82 degreeC.

[Comparative Example 4]
Use of polyester resin H, and supply amount of ammonia water having a concentration of 25% by mass to 16 g (corresponding to 1.0 times equivalent of ammonia to the acid value of polyester resin), and supply of distilled water to 504 g A polyester resin aqueous dispersion was obtained in the same manner as in the production method described in Example 1 with modification. In addition, the stirring temperature of stirring process (I) was 50-55 degreeC, and the stirring temperature of stirring process (II) was 75-79 degreeC.

[Comparative Example 5]
The stirring temperature in the stirring step (II) is changed to the same temperature as the stirring temperature in the stirring step (I), and the amount of ammonia water having a concentration of 25% by mass is 7.2 g (based on the acid value of the polyester resin). 1.0 equivalent of ammonia), the amount of distilled water charged was changed to 513 g, and an aqueous polyester resin dispersion was obtained in the same procedure as in the production method of Example 1. Specifically, the stirring temperature in the stirring step (I) was 58 to 62 ° C, and the stirring temperature in the stirring step (II) was also set to 58 to 62 ° C.

[Comparative Example 6]
The stirring temperature of the stirring step (I) is changed to the same temperature as the stirring temperature of the stirring step (II), and the amount of ammonia water having a concentration of 25% by mass is 7.2 g (based on the acid value of the polyester resin). 1.0 equivalent of ammonia), the amount of distilled water charged was changed to 513 g, and an aqueous polyester resin dispersion was obtained in the same procedure as in the production method of Example 1. Specifically, the stirring temperature in the stirring step (I) was 78 to 82 ° C, and the stirring temperature in the stirring step (II) was also set to 78 to 82 ° C.

[Comparative Example 7]
25 g of a 10% by mass aqueous solution of a surfactant (manufactured by Aldrich, “IgepalCO720”) was added, and the amount of ammonia water having a concentration of 25% by mass was 7.2 g (1.0 times the acid value of the polyester resin). Equivalent to ammonia), the charged amount of distilled water was changed to 513 g, and an aqueous polyester resin dispersion was obtained in the same procedure as in the production method of Example 1. The stirring temperature in the stirring step (I) and the stirring step (II) was also the same as in Example 1.

[Comparative Example 8]
The production method described in Example 1 except that the temperature in the stirring step (I) is 48 to 52 ° C, that is, less than (Tg-10) ° C, and the temperature in the stirring step (II) is 75 to 79 ° C. A polyester resin aqueous dispersion was obtained in the same procedure as described above.

[Comparative Example 9]
A polyester resin aqueous dispersion was obtained in the same procedure as the production method described in Example 1, except that the stirring time in the stirring step (I) was 25 minutes.

[Comparative Example 10]
A polyester resin aqueous dispersion was obtained in the same procedure as in the production method described in Example 1, except that the stirring time in the stirring step (II) was 55 minutes.

[Comparative Example 11]
The ammonia water having a concentration of 25% by mass was changed to 11 g of triethylamine (corresponding to 1.05 times equivalent of triethylamine with respect to the acid value of the polyester resin), and the same procedure as in the production method described in Example 1 was used. Thus, an aqueous polyester resin dispersion was obtained. The stirring temperature of the stirring step (I) was 68 to 72 ° C.

  Tables 3, 4 and 5 show the evaluation results of the polyester resin aqueous dispersions obtained in Examples 1 to 20 and Comparative Examples 1 to 11 and the evaluation results of the polyester resin coatings obtained using the aqueous dispersions. Shown in In addition, the addition amount of ammonia in Tables 3-5 was described as the amount of ammonia when ammonia water was used.

表５において、※１は内容物全体が凝集してしまい、水性分散体を得ることができなかったことを示す。

In Table 5, * 1 indicates that the entire contents were aggregated and an aqueous dispersion could not be obtained.

  As is clear from Table 3, when the method for producing a polyester resin aqueous dispersion of the present invention as in Examples 1 to 20 is used, there is no occurrence of poor dispersion or precipitate, and the polyester resin is in a state of good dispersion efficiency. An aqueous dispersion could be obtained. In addition, the obtained aqueous dispersion is very excellent in long-term storage stability, and the resin film obtained from the aqueous dispersion has a film forming property, water resistance, alcohol resistance, chemical resistance and Excellent bending resistance. Furthermore, since the resin coating is obtained from an aqueous dispersion, it is very excellent in that the burden on the environment can be reduced.

  In Comparative Example 1, terephthalic acid was not contained in the polyester resin used in a proportion of 60 mol% or more. Therefore, the resin film obtained from the produced aqueous dispersion has poor alcohol resistance.

  In Comparative Example 2, the polyester resin used did not contain ethylene glycol as an alcohol component in a proportion of 40 mol% or more. Therefore, the resin film obtained from the produced aqueous dispersion has poor chemical resistance.

  In Comparative Example 3, the acid value of the polyester resin used was less than 4 mgKOH / g. For this reason, solids aggregated in the aqueous dispersion, and an aqueous dispersion could not be obtained.

  In Comparative Example 4, the acid value of the polyester resin used exceeded 40 mgKOH / g. Therefore, the obtained resin film was poor in water resistance and chemical resistance, and was slightly inferior in flex resistance.

  In Comparative Example 5, the stirring temperature in the stirring step (II) of the method for producing an aqueous dispersion was less than (Tg of polyester resin + 10) ° C. Therefore, a large amount of poor dispersion occurred, and only an aqueous dispersion with low dispersion efficiency was obtained. Further, the obtained aqueous dispersion was inferior in storage stability.

  In Comparative Example 6, the stirring temperature in the stirring step (I) in the method for producing an aqueous dispersion exceeded the Tg of the polyester resin. Therefore, a large amount of poor dispersion occurred, and only an aqueous dispersion having low dispersion efficiency was obtained.

  In Comparative Example 7, an aqueous dispersion was obtained using a surfactant. Therefore, the resin film obtained from the aqueous dispersion has poor water resistance.

  In Comparative Example 8, since the temperature in the stirring step (I) was less than (Tg-10) ° C., the dispersion efficiency at the end of the stirring step (I) and the stirring step (II) was low and obtained. The aqueous dispersion was inferior in storage stability.

  In Comparative Example 9, since the stirring time in the stirring step (I) was too short, the dispersion efficiency at the end of the stirring step (I) and the stirring step (II) was low, and the obtained aqueous dispersion was storage stable. It became inferior.

  In Comparative Example 10, since the stirring time in the stirring step (II) was too short, the dispersion efficiency at the end of the stirring step (II) was low, and the obtained aqueous dispersion was inferior in storage stability. It was.

  In Comparative Example 11, an aqueous dispersion was obtained using triethylamine as a basic compound instead of ammonia. Therefore, the obtained aqueous dispersion was inferior in storage stability, and in addition, inferior in water resistance, alcohol resistance, chemical resistance and flex resistance.

Claims (5)

A polyester resin containing an acid component containing 60 mol% or more of terephthalic acid and an alcohol component containing 40 mol% or more of ethylene glycol and having an acid value of 4 to 40 mg KOH / g is organic without using a surfactant. A method for producing an aqueous polyester resin dispersion, comprising mixing in an aqueous medium together with a solvent and ammonia, and then performing the following stirring step (I) and stirring step (II) in this order.
Stirring step (I) (Glass transition temperature of polyester resin −10) Step of stirring polyester resin at a dispersion efficiency of 80% or more by stirring for 30 minutes or more at a temperature not lower than (glass transition temperature) ° C.
Stirring Step (II) (Glass Transition Temperature of Polyester Resin +10) A step of stirring the polyester resin at a dispersion efficiency of 97% or more by stirring at a temperature of 60 ° C. or higher.
In the stirring step (I) and the stirring step (II), the dispersion efficiency of the polyester resin is the ratio of the mass of the polyester resin actually dispersed in the aqueous dispersion to the mass of the polyester resin used. It is shown.   2. The method for producing an aqueous polyester resin dispersion according to claim 1, wherein in the stirring step (I), stirring is performed at a peripheral speed of the stirring blade of 0.2 to 2.0 m / s.   The method for producing an aqueous polyester resin dispersion according to claim 1 or 2, wherein in the stirring step (II), stirring is performed at a peripheral speed of the stirring blade of 0.1 to 1.5 m / s.   A polyester resin aqueous dispersion produced by the production method according to claim 1.   A resin film formed from the aqueous polyester resin dispersion according to claim 4.