JP3565129B2 - Production method of saturated copolymerized polyester resin solution - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a saturated copolymerized polyester resin (hereinafter simply abbreviated as polyester) used for paints, adhesives, coating agents, and the like, and a method for producing a polyester solution that can be used for producing powder of the polyester. And a method for producing a solution capable of rapidly and easily dissolving in a solvent.
[0002]
[Prior art]
A polyester solution obtained by dissolving polyester in a solvent has been put to practical use in paints, adhesives, coating agents, binders and the like. In addition, the polyester is once dissolved in an organic solvent, the solution is mixed and dispersed in water, and then the organic solvent is removed to produce a water-dispersed polyester coating agent. Polyester solutions are used in a wide range of fields, such as producing polyester powder by dispersing in a poor solvent to precipitate polyester and then drying the obtained powder.
[0003]
The method of dissolving the polyester in the solvent is a method in which the polyester in a solid state is roughly cut into pieces or processed into pellets and the polyester is dissolved in the solvent, or the polyester in the molten state is directly poured into the solvent. Generally, a method of dissolving by stirring is used. In the method of dissolving the polyester in the solid state, the polyester is processed into a shape having a high dissolution rate in advance as described above, or while taking measures such as heating the solvent, the dissolution rate is still insufficient and necessary for dissolution. There is a problem that the required time is long.
In addition, in the method of dissolving the polyester in a molten state by pouring it into a solvent, the synthesized polyester can be dissolved as it is, and the polyester is cooled and solidified, and the process of shredding or processing into pellets and the energy required there are reduced. Although there is an advantage that can be obtained, there are problems such as that the molten polyester charged into the solvent becomes a lump and the dissolution rate is slowed down, and solidification and deposition are caused on a portion having poor fluidity during the dissolution stirring, resulting in a decrease in solubility.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to solve the problems of the conventional polyester dissolving method and to provide a method for producing a solution obtained by quickly and efficiently dissolving the polyester in a solvent.
[0005]
[Means for Solving the Problems]
The present inventors have intensively studied to solve the problems of the conventional method as described above, and as a result, by specifying specific dissolving conditions, a polyester can be easily dissolved in a solvent in a short time. And found that the present invention can be dissolved, and completed the present invention. That is, the present invention comprises the following inventions.
[1] In the first invention, gravity acts on the melt under stirring with a stirring blade having a rotation axis in the vertical direction at a shearing rate of 5 sec- ¹ or more and 50 sec- ¹ or less. The saturated copolymerized polyester resin is dissolved in the solvent by circulating the melt in the direction or in the opposite direction so that the liquid circulation amount with respect to the total amount of the melt is 0.3 hours- ¹ or more and 20 hours- ¹ or less. And a process for producing a saturated copolymerized polyester resin solution.
[2] The second invention is characterized in that the inert gas is blown into the melt so that the amount of the inert gas with respect to the total amount of the melt is not less than 0.1 hr- ^{1 and not} more than 10 hr- ^1. [1] A method for producing a saturated copolymerized polyester resin solution, which comprises performing the production method described in [1] .
[ 3 ] A third invention relates to the method for producing a saturated copolymerized polyester resin solution according to the above [1] or [2], wherein the saturated copolymerized polyester resin is dissolved in a solvent while boiling the melt. Things.
Here, the melt refers to a mixture of polyester, a solvent, and a solution comprising the same.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Examples of the repeating unit (monomer) constituting the polyester of the present invention include, but are not limited to, the following components.
Examples of the acid component include aromatic compounds such as terephthalic acid, isophthalic acid, phthalic anhydride, α-naphthalenedicarboxylic acid, β-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, and esters thereof. Aliphatic dicarboxylic acids such as dicarboxylic acid, oxalic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecylenic acid, dodecane diacid, and ester-forming products thereof, 1,4-cyclohexanedicarboxylic acid, tetrahydroanhydride Alicyclic dicarboxylic acids such as phthalic acid and hexahydrophthalic anhydride; In addition, other carboxylic acids such as trimellitic acid and pyromellitic acid can be used together within a range that does not impair gelation during synthesis of the polyester or solubility of the polyester in a solvent.
[0007]
As the polyol component, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, Fats such as 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, 3-methylpentanediol, 2,2,3-trimethylpentanediol, diethylene glycol, triethylene glycol and dipropylene glycol And alicyclic glycols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol, and aromatic glycols such as bisphenol A. Polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol can also be used in combination as long as gelling during polyester synthesis and solubility of the polyester resin in a solvent are not impaired.
[0008]
The polyester used in the present invention can be synthesized by a general method, and is subjected to an esterification reaction between the above-mentioned acid component and a polyol component, followed by polycondensation while distilling off excess glycol under high temperature and high vacuum. It can be synthesized by a direct esterification method or a transesterification method using a dicarboxylic acid ester-forming product.
[0009]
As the solvent used in the present invention, any solvent can be used as long as it can dissolve the polyester. For example, one or more organic solvents such as aliphatic, alicyclic, aromatic hydrocarbon compounds, aliphatic ester compounds, alcohol compounds, ether compounds, ketone compounds, and halogen hydrocarbon compounds, or Water, an aqueous solution in which an organic substance is mixed with water, and the like are not limited thereto. Among the above solvents, hexane, aliphatic hydrocarbons such as petroleum ether, cyclohexane, alicyclic hydrocarbons such as cyclohexene, xylene, aromatic hydrocarbon compounds such as toluene, ethyl acetate, propyl acetate, acetic acid Various organic solvents such as aliphatic ester compounds such as butyl, alcohol compounds such as methanol, ethanol, butanol, and ethylene glycol; ether compounds such as diethyl ether; methyl ethyl ketone, diisobutyl ketone, acetone, and ketone compounds such as cyclohexanone; That mixture is preferred. In the polyester solution of the present invention, the solvent is preferably used in a proportion of 20 to 95% by weight based on the resin composition.
[0010]
In the solution produced in the present invention, a modifier other than the polyester dissolved in the solvent can be blended without any particular limitation. Specific examples thereof include urethane resins, epoxy resins, acrylic resins, novolak resins, phenoxy resins, butyral resins, ketone resins, and the like, and these may be used alone or in combination of two or more. be able to. If necessary, a plasticizer such as an epoxidized oil and dioctyl phthalate can be appropriately added. Further, additives such as coloring agents such as coloring pigments, anti-sagging agents, surface conditioners, crosslinking accelerators, ultraviolet absorbers, light stabilizers, and antioxidants, and stabilizers can be used as necessary.
[00011]
Polyester is a method in which the molten resin after the completion of the polymerization reaction is dissolved as it is, pelletized or formed into a sheet and dissolved in a solid state, or a once pelletized or sheeted solid state polyester is melted by heating and melting. Can be used with
[0012]
As a method for dissolving the polyester of the present invention, for example, (1) a solvent adjusted to an appropriate temperature is previously charged into a dissolving tank, and the resin in a molten state is passed through a die, a perforated plate or a grid-like plate to form a strand or sheet. (2) a method in which a solvent adjusted to an appropriate temperature is previously charged in a dissolving tank, and polyester pellets are dissolved in the solvent and then dissolved.
[0013]
As shown in FIG. 1, the dissolving equipment used in the present invention is a dissolving tank 1 having a stirrer and a stirring blade, an input port 8 for charging a solvent, an input port 9 for charging a resin, and circulating and / or discharging the melt. Transfer device 3 such as a pump for heating, an external heat exchanger 4 for heating or cooling a melt (mixture of solvent and resin), a heat exchanger 10 for condensing a partially evaporated solvent, etc. Consists of When the melting tank 1 has a jacket having a sufficient heat exchange capacity, the external heat exchanger 4 can be omitted. However, when the resin easily accumulates on the bottom, as shown in FIG. 2, the liquid transfer device 3 can be sucked from the middle or upper supernatant of the dissolution tank and returned into the reactor from the bottom of the dissolution tank. preferable.
[0014]
In the present invention, the liquid transfer device 3 is a liquid transfer device having a circulation capacity of 0.3 hours ^-1 or more with respect to the total volume [L] of the dissolved material in the dissolving tank 1, that is, the total volume [L of the dissolved material. ] Is multiplied by 0.3 with a liquid transfer device having a circulation capacity of not less than a circulation amount [L / hour]. In order to make the liquid near the bottom extraction nozzle of the dissolving tank 1 in which the flow of the melt hardly occurs and the resin and the like easily accumulate, the melt that has accumulated there is used by the circulation pump 3 to make the total volume of the melt. The dissolution is promoted by returning to the inside of the dissolving tank 1 with a circulation amount of 0.3 hour- ¹ or more with respect to [L]. When the circulation amount is less than 0.3 hour- ¹ , the dissolution rate is low, and the effect of improving the dissolution rate by liquid circulation is not sufficient. The upper limit of the circulation amount is not particularly limited, but from an economical point of view such as the liquid circulation efficiency in consideration of the pump power (electric power consumption) and the piping pressure loss, is preferably 20 hours- ¹ or less, particularly preferably 10 hours- ¹ or less. is there. If necessary, a solid-liquid separation device such as a strainer can be attached to the suction port in order to prevent damage to the liquid transfer device due to biting of the undissolved resin.
[0015]
In the present invention, in order to improve the dissolution rate of the dissolved material, particularly, the flow of the dissolved material is less likely to occur, and the liquid near the bottom extraction nozzle of the dissolving tank 1 where the resin and the like are easily deposited flows in the lower part of the dissolving tank. or from blowing valve 2 to the inside, the total volume of the lysate [L] 0.1 hr ^-1 or more with respect to, i.e., the total volume [L] blow amount multiplied by 0.1 to lysate [L / [Time], an inert gas such as nitrogen, helium, neon, argon or the like is blown, and the resin or the melt remaining in the lower portion of the melter is rolled up into the melter by the inert gas to promote the melt. If blowing of the gas is less than 0.1 over ¹ hour, the dissolution accelerating effect is small, and the force to wind the retentate is not observed blow effect because of insufficient. Although there is no particular upper limit for the amount of blowing, economical factors such as an increase in the running cost due to an increase in the amount of gas and a loss of the solvent due to the flow of the solvent vapor into the waste gas treatment facility without being condensed by the condenser (10 in FIGS. 1 and 2). Considering the problem, the blowing amount is preferably 10 hours- ¹ or less, particularly preferably 5 hours- ¹ or less.
In the present invention, it is more preferable to simultaneously perform the liquid circulation and the inert gas blowing according to the present invention from the viewpoint of increasing the dissolution rate.
[0016]
The stirring of the melt in the present invention is preferably performed under a stirring condition of a shear rate of 5 seconds- ¹ or more in order to secure a sufficient flow. In the present invention, the shear rate is the average value of the shear velocity gradient of the liquid at the tip of the stirring blade and the liquid near the inner wall of the stirring tank, and the shear rate γ is the shear velocity gradient Δu and the distance between the tip of the stirring blade and the inner wall of the tank. s is calculated as γ = △ u / △ s. Under stirring conditions where the shear rate does not reach 5 seconds- ¹ , the dissolution rate is low and productivity is poor. There is no particular upper limit for the shear rate, but from the viewpoint of economy (the relationship between the power consumption and the stirring efficiency), the shear rate is preferably 50 seconds- ¹ or less, particularly preferably 30 seconds- ¹ or less.
[0017]
The dissolution temperature of the present invention is preferably a temperature that is the boiling point of the melt and does not cause quality deterioration such as thermal deterioration of the resin. The amount of vapor generated by the boiling of the solvent may be such that the total volume [L] of the melt is multiplied by 0.1 and the volume is [L / hour] or more and the condensing capacity of the heat exchanger 10 or less. Are particularly preferred. By keeping the melt in a boiling state in this way, the flow of the solvent vapor generated in the melting tank is improved by the bubbles of the generated solvent vapor, and the dissolution can be promoted. The dissolution pressure can be increased or increased as necessary.
[0018]
In the method for producing a polyester solution of the present invention, the stirring method of the second invention or the boiling of the melt of the third invention, or the stirring method of the second invention, simultaneously with the liquid circulation or / and the addition of the inert gas according to the present invention. The combination of boiling of the melt of the third invention and the third invention is a more preferable method from the viewpoint of improving the dissolution rate.
[0019]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.
[0020]
[Reference Example 1]
<Synthesis of polyester>
271 kg of dimethyl terephthalate, 450 kg of ethylene glycol and 265 kg of neopentyl glycol are used as main raw materials, and 0.135 kg of zinc acetate dihydrate is charged as a catalyst. After that, 155 kg of isophthalic acid, 102 kg of adipic acid, 330 kg of sebacic acid and 0.34 kg of antimony trioxide were added, and water was distilled off at 180 to 220 ° C. to carry out an esterification reaction. Subsequently, excess glycol was distilled off while gradually raising the temperature to 220 to 245 ° C under reduced pressure. The weight average molecular weight (in terms of PSt) of the obtained polyester resin by GPC was 70,000, and the monomer composition by H ¹ -NMR analysis was such that the molar ratio of the acid component was terephthalic acid / isophthalic acid / adipic acid / sebacic acid = 30 / 20/17/33, the polyol component was ethylene glycol / neopentyl glycol = 70/30 in molar ratio.
[0021]
[Example 1]
<Dissolution of polyester>
Using the apparatus shown in FIG. 1, 1096 kg of ethyl acetate was charged as a solvent into a dissolution tank, and 998 kg of the polyester resin obtained in Reference Example 1 was transferred through a pipe heated to 200 ° C., and charged into the dissolution tank over 2 hours. . Immediately after the completion of the introduction of the resin, the temperature of the melt was maintained at 60 ° C., and the mixture was stirred at a constant stirring shear rate of 10.4 sec− ^{1, and} at the same time, 2 m ³ / Hr (with respect to the total volume [L] of the melt) by the pump 3. (The circulation amount was 1.0 hour- ¹ time), and the heating and melting were continued for 18 hours. After cooling to 40 ° C., the solid content concentration was adjusted to 45%, and the melt was extracted from the melting tank. No residual polyester was found in the dissolution tank, and the desired polyester solution could be obtained 20 hours after the start of dissolution.
[0022]
[Example 2]
Using the apparatus of FIG. 2, polyester was charged under the same conditions as in Example 1 and stirring was started. In Example 1, the liquid was not circulated by the pump immediately after the completion of the resin introduction, but instead, nitrogen gas was supplied at 1 m ³ / Hr (total of the dissolved material) from the inert gas blowing valve 2 in the pipe below the dissolving tank. The polyester was dissolved in the same manner as in Example 1 except that the polyester was dissolved while blowing at a rate of 0.5 hour to ¹ time with respect to the volume [L]. After the polyester resin was charged, the heating and melting were continued for 15 hours, and then circulation from the bottom outlet to the inside of the melting tank was started, and the heating and stirring and melting were continued for 4 hours. After cooling to 40 ° C., the solid content concentration was adjusted to 45%, and the melt was extracted from the melting tank. No residual polyester remained in the dissolution tank, and the desired polyester solution could be obtained 21 hours after the start of dissolution.
[0023]
[Example 3]
Using the apparatus shown in FIG. 1, 998 kg of the polyester obtained in Reference Example 1 was charged into a dissolution tank with 1096 kg of ethyl acetate as a solvent, and the polyester obtained in Reference Example 1 was transferred through a pipe heated to 200 ° C. It was charged into the dissolution tank over time. After the polyester is charged, circulation is started while circulating at 2 m ³ / Hr (a circulation amount of 1.0 hour to ¹ time with respect to the total volume of the melt [L]) by the pump 3 from the bottom outlet to the inside of the dissolution tank. At the same time, the mixture was stirred at a jacket temperature of the melting tank of 90 ° C. and a shear rate of 10.4 sec- ¹ constant, and the steam generation amount was 1.2 m ³ / Hr on average (based on the total volume of the melt [L]. then 0.6 h ^-1 time blow amount) Te was dissolved while refluxing the vapors in the condenser 10. After the introduction of the polyester resin, the dissolution was continued for 12 hours under the above conditions. The temperature of the lysate during lysis was about 79 ° C. Subsequently, after cooling the whole liquid to 40 ° C., the solid content was adjusted to 45%, and the dissolved substance was extracted from the dissolving tank. No residual polyester resin remained in the dissolution tank, and the desired polyester solution could be obtained 14 hours after the start of dissolution.
[0024]
【The invention's effect】
The polyester solution can be easily and quickly dissolved in a solvent by the method for producing a polyester solution according to the present invention, and can be widely used in the chemical industry or the like for producing or using a polyester solution.
[Brief description of the drawings]
FIG. 1 is a flow chart 1 showing the concept of an apparatus used to carry out the method of the present invention.
FIG. 2 is a flowchart 2 showing the concept of an apparatus used to carry out the method of the present invention.
[Explanation of symbols]
1: dissolution tank having a stirrer 2: inert gas blowing valve 3: liquid transfer device 4 for circulating and / or discharging the dissolved material 4: external heat exchanger 5 for heating and cooling the dissolved material , 14: refrigerant or heat medium inlet line 6, 15: refrigerant or heat medium outlet line 7: discharge line 8 for dissolving material: input line 9 for inputting solvent 9: input line 10 for inputting resin composition: condenser 11: refrigerant Inlet line 12: Refrigerant outlet line 13: Line to waste gas treatment facility

Claims (3)

The stirring blade having a rotating axis in the vertical direction dissolves the melt in the direction in which gravity acts or in the opposite direction while stirring the melt under stirring conditions in which the shear rate is 5 sec- ¹ or more and 50 sec- ¹ or less. The saturated copolymerized polyester resin is dissolved in a solvent by circulating the dissolved product so that the liquid circulation amount with respect to the total amount of the product is 0.3 hours- ¹ or more and 20 hours- ¹ or less. A method for producing a polymerized polyester resin solution. 2. The method according to claim 1, wherein the inert gas is blown into the melt so that the amount of the inert gas with respect to the total amount of the melt is from 0.1 hours ^{-1 to} 10 hours ^-1. A method for producing a saturated copolymerized polyester resin solution. The method for producing a saturated copolymerized polyester resin solution according to claim 1 or 2, wherein the saturated copolymerized polyester resin is dissolved in a solvent while boiling the solution.

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