JP2010174213A - Process for producing polyester composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for producing a polyester composition suitable to apply to a polyester film with uniformly dispersed silica, excellencies in productivity, large unevenness on the surface and favorable deflation. <P>SOLUTION: The process for producing the polyethylene terephthalate polyester composition by an esterification reaction and a polycondensation reaction to give the polyester composition includes: adding a catalyst, a phosphoric acid ester and an alkaline earth metal compound to a low polymerized polyester after the esterification reaction; agitating the reaction mixture for 0.5-2 hours; adding a silica/ethylene glycol-dispersed solution containing 2-20 mass% of silica with an average particle size of 1-10 μm and maximum particle size of less than 20 μm thereto, so that 0.5-3 mass% of silica is contained in the polyester composition, at a temperature of 240-300°C of the low polymerized polyester; and continuously performing polycondensation reaction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a polyester composition. More specifically, the present invention relates to a method for producing a polyester composition that can provide a polyester film that is excellent in productivity and good in air bleeding.

  Polyesters are widely used as various films and sheets because they have excellent chemical and physical properties. However, the polyester film has a drawback of poor air escape, and air accumulation may occur when performing adhesion or bonding.

  This defect occurs because the polyester film is in close contact with the air passage and is mainly due to the surface state of the polyester film.

  So far, various methods have been proposed to improve the air bleedability of the polyester film. For example, Patent Document 1 proposes a method of forming a large number of fine or non-penetrating holes having a pore diameter of several μm to several tens of μm in a polyester film. However, the film obtained by this method has problems such as a problem in strength and a post-processing of the film.

  In addition, a method for forming irregularities on the film surface by causing fine particles to be present in the polyester composition has been proposed. In this method, a part or all of a catalyst and a coloring inhibitor used in polyester polymerization are deposited in the course of the polymerization reaction to be present as fine particles, and inorganic fine particles are added from the outside at an arbitrary stage during polyester polymerization. Broadly divided into methods.

  However, the method of precipitating fine particles in the polyester polymerization reaction process has problems that it is difficult to control the amount of particles and the particle diameter, and it is difficult to avoid the generation of coarse particles.

  In Patent Documents 2 and 3, etc., as a method of adding inorganic particles from the outside, silica, titanium oxide, barium sulfate, silicon oxide-magnesium oxide compound, silica-alumina compound, alumina compound, glass powder, calcium carbonate, clay, A method of adding mica, talc and the like to polyester has been proposed. Depending on the application, those having an average particle diameter of 0.001 to 10 μm are properly used. However, it is difficult to avoid the generation of coarse particles due to aggregation of inorganic fine particles.

  In order to suppress aggregation of inorganic particles, Patent Document 4 proposes a method of adding a phosphorus compound having a specific chemical structure to an esterified product. However, the phosphorous compounds described in the literature are disadvantageous in production because of their high cost.

JP-A-9-252718 Japanese Patent Publication No.59-8216 Japanese Patent Laid-Open No. 52-3645 JP 2007-224238 A

  An object of the present invention is to improve the dispersibility of silica in polyester and suppress the formation of coarse particles, thereby producing a polyester composition that can produce a polyester film that is excellent in productivity and good in air release properties. Is to provide.

  As a result of investigations to solve the above-mentioned problems, the present inventors have determined that a specific method for adding an additive such as a catalyst and a specific silica / ethylene glycol dispersion in a polycondensation reaction of a polyester low polymer. It has been found that the addition of the silica gel can suppress the formation of coarse silica particles in the polyester composition, and the present invention has been achieved.

  That is, the present invention provides a polyester after completion of the esterification reaction in producing a polyester composition containing terephthalic acid as a main component as a dicarboxylic acid component and ethylene glycol as a main component as a glycol component by an esterification reaction and a polycondensation reaction. After adding the catalyst, phosphate ester and alkaline earth metal compound to the low polymer, stirring is performed for 0.5 to 2 hours, then the average particle size is 1 to 10 μm, and the maximum particle size is less than 20 μm. The temperature of the polyester low polymer is 240 to 300 ° C. so that the silica / ethylene glycol dispersion containing 2 to 20 mass% of a certain silica contains 0.5 to 3 mass% of silica with respect to the polyester composition. Polyethylene terephthalate-based polyester composition characterized in that it is added in a state and subsequently undergoes a polycondensation reaction The gist of the manufacturing method of the product.

  According to the present invention, silica can be contained in a polyester composition with good dispersibility without generating coarse silica particles. Therefore, the average particle diameter of silica in the polyester composition obtained by the present invention can be made substantially equal to the average particle diameter before addition to the composition, and the maximum particle diameter can be less than 20 μm. Therefore, an increase in the filtration pressure can be suppressed during molding, and the polyester film obtained therefrom can be made into a polyester film having excellent productivity and good air bleeding.

Hereinafter, the present invention will be described in detail.
The polyester composition referred to in the present invention is a polyethylene terephthalate-based polyester composition containing terephthalic acid as a main component as a dicarboxylic acid component and ethylene glycol as a main component as a glycol component. A part of the dicarboxylic acid component may be replaced with another dicarboxylic acid component, and a part of the glycol component may be replaced with another glycol component.

  Other dicarboxylic acid components include isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, succinic acid, adipic acid, sebacic acid, 5-sodium isophthalic acid And oxycarboxylic acids such as p-β-oxyethoxybenzoic acid or esters thereof.

  Other glycol components include alkylene glycols having 2 to 10 carbon atoms, 1,4-cyclohexanedimethanol, neopentyl glycol, 1,4-bis (β-oxyethoxy) benzene, bisglycol ether of bisphenol A, Examples include polyalkylene glycol.

  Furthermore, within the range in which the polyester is substantially linear, a polycarboxylic acid such as trimellitic acid and pyromellitic acid, a polyol such as pentaerythritol, trimethylolpropane, and glycerin, and a polymerization terminator such as phenylacetic acid may be used. good.

  In the present invention, first, an esterification reaction is carried out using the above raw materials to obtain a polyester low polymer. The esterification reaction is carried out by charging terephthalic acid and ethylene glycol into an esterification reaction vessel so that the molar ratio is terephthalic acid: ethylene glycol = 1.4 to 1.8, and stirring in a molten state at 250 to 260 ° C. under normal pressure. This can be done.

  The average degree of polymerization of the polyester low polymer used in the present invention is not particularly limited, but is preferably 2.0 to 10.0, more preferably 4.0 to 8.0.

  In the present invention, a catalyst, a phosphate ester, and an alkaline earth metal compound described below are added to the polyester low polymer described above.

  The catalyst used in the present invention is added to perform a polycondensation reaction, and specifically, antimony, germanium, tin, titanium, zinc, aluminum, magnesium, potassium, calcium, sodium, generally used, In addition to metal compounds such as manganese and cobalt, organic sulfonic acid compounds such as sulfosalicylic acid and o-sulfobenzoic anhydride can be used.

The addition amount of the catalyst is not particularly defined, but from the viewpoint of polymerizability, thermal stability, etc., preferably 0.5 × 10 ^{−4 to} 5.0 × with respect to 1 mol of the acid component constituting the polyester. 10 ^-4 mol, more preferably 2.0 × ¹⁰ -4 to 4.0 × ^{10 -4} mol.

  The phosphoric acid ester used in the present invention is added as a heat stabilizer for suppressing thermal decomposition at the time of melting and improving the color tone, and specifically includes triethyl phosphate, trimethyl phosphate, dimethyl phosphate, diethyl phosphate and the like. It is done.

The addition amount of the phosphate ester is not particularly specified, but from the viewpoint of color tone improvement effect, thermal stability, etc., preferably 0.5 × 10 ⁻⁴ to 30 to 1 mol of the acid component constituting the polyester. × ^{10 -4} mol, more preferably from 1.0 × ¹⁰ -4 to 20 × ^{10 -4} mol.

The alkaline earth metal compound used in the present invention is added as a pinning agent in terms of improving the winding property when the resulting polyester composition is formed into a film. Specifically, magnesium acetate, calcium acetate, Examples thereof include magnesium oxalate, calcium propinate, calcium stearate, magnesium stearate, calcium benzoate and the like.
The addition amount of the alkaline earth metal is not particularly specified, but is preferably 2.0 × 10 ⁻⁴ to 50 with respect to 1 mol of the acid component constituting the polyester, from the viewpoints of polymerizability and thermal stability. × ^{10 -4} mol, more preferably from 4.0 × ¹⁰ -4 to 40 × ^{10 -4} mol.

  In the present invention, it is necessary to add the above-mentioned catalyst, phosphate ester and alkaline earth metal compound to the polyester low polymer after completion of the esterification reaction and then stir for 0.5 to 2 hours. Preferably, it is 0.7 to 1.8 hours, and more preferably 0.8 to 1.5 hours. When the stirring time is less than 0.5 hour, the dispersibility of silica added in the next step is deteriorated, and coarse particles due to aggregation are likely to be generated, which cannot be employed. This is thought to be due to the fact that the additives are dense at the beginning of stirring, and the intermolecular force that attracts silica becomes strong, making it easy to become the core of aggregation. On the other hand, if it exceeds 2 hours, the deterioration of the color tone and many by-products are generated due to the thermal deterioration of the polyester low polymer, and the production efficiency is lowered. The stirring method here is not limited in any way, but it can be carried out with an arbitrary number of stirring using a paddle type, anchor type, double helical type stirring blade or the like.

  Further, the temperature of the polyester low polymer at the time of stirring is not particularly specified, but in order to suppress the deterioration of color tone and the generation of by-products due to thermal degradation of the polyester low polymer, it is preferable to be 300 ° C. or less, More preferably, it is 280 degrees C or less.

  The order of addition of the above-described catalyst, phosphate ester and alkaline earth metal compound is not particularly defined, and any order of addition can be adopted.

  In the present invention, it is necessary to add a silica / ethylene glycol dispersion described below after stirring for the predetermined time described above. When the silica / ethylene glycol dispersion is added first and stirring is performed for a predetermined time, and then an additive such as a catalyst is added, the additive is added to the low-polyester polymer containing silica in a dense state. Therefore, it becomes necessary to add a catalyst or the like and add a silica / ethylene glycol dispersion after stirring.

  The silica / ethylene glycol dispersion used in the present invention is one in which silica is dispersed in ethylene glycol at a concentration of 2 to 20% by mass, preferably 5 to 15% by mass, more preferably 8 to 12% by mass. Silica concentration. When the silica concentration is less than 2% by mass, it is necessary to add a large amount of the dispersion, the polyester low polymer is likely to solidify due to a decrease in temperature, and it takes time to remelt, and the amount of ethylene glycol used. Can not be adopted because of an increase in productivity and a decrease in productivity. On the other hand, when the amount exceeds 20% by mass, coarse particles due to aggregation of silica are likely to occur in the dispersion, which cannot be employed.

  The average particle size of silica present in the silica / ethylene glycol dispersion used in the present invention is required to be 1 to 10 μm, preferably 3 to 8 μm, and more preferably 4 to 6 μm. When the average particle size is less than 1 μm, the surface irregularity is small when the film is formed, and the air escape property becomes insufficient. On the other hand, if it exceeds 10 μm, the filtration pressure rises due to clogging of the filter of the melt extruder during film formation, or it becomes a defect of the film and cannot be employed.

  In addition, the maximum particle size of silica present in the silica / ethylene glycol dispersion must be less than 20 μm. If the particle diameter is 20 μm or more, the filtration pressure increases due to clogging of the filter of the melt extruder at the time of film formation, or a defect of the film cannot be adopted.

  The average particle size and the maximum particle size of silica referred to in the present invention are values obtained by measurement using a laser diffraction particle size distribution measuring device (SALD-2000 manufactured by Shimadzu Corporation). A slurry in which silica is added to ethylene glycol so as to be 2% by mass is prepared, and a dispersion obtained by performing stirring and sonolator ultrasonic dispersion treatment for 2 hours is used to measure the diffraction / scattered light intensity of 40 to 60% with the above measuring apparatus. The dilution was adjusted with ethylene glycol so as to be within the range, and the average value of those measured at n = 4 was taken.

  The silica used in the present invention is not particularly specified. However, since the secondary particles are strongly bonded to each other, primary particles of about several nanometers are hardly seen, and the particle size distribution is sharp. Is preferred. Specifically, AZ-400 and CX-400 manufactured by Tosoh Silica Co., Ltd., and SY-350 and SY-430 manufactured by Fuji Silysia Chemical Co., Ltd. can be preferably used. Absent.

  The silica / ethylene glycol dispersion used in the present invention is not particularly limited with respect to the production method. However, ethylene glycol is filled in a stirring tank in advance, and the silica in a powder state has a predetermined concentration while stirring ethylene glycol. The mixture is stirred for a sufficient period of time and then subjected to ultrasonic dispersion treatment using a sonolator, homogenizer, or the like.

  In the present invention, the addition amount of the silica / ethylene glycol dispersion needs to be added in such an amount that the content of silica in the obtained polyester composition is 0.5 to 3% by mass. It is preferable to set it as mass%, and it is more preferable to set it as 1.5-2.0 mass%. When it is less than 0.5% by mass, there are few surface irregularities when it is made into a film, and the air escape property becomes insufficient. On the other hand, when it exceeds 3% by mass, the dispersibility of silica is deteriorated due to aggregation. Since coarse particles are likely to be generated, neither can be employed.

  Moreover, in this invention, it is necessary to make the temperature of the polyester low polymer at the time of adding the above-mentioned silica / ethylene glycol dispersion liquid into a polyester low polymer set to 240-300 degreeC, Preferably it is 260-280 degreeC. Yes, more preferably 265-275 ° C. When the temperature is less than 240 ° C., when the silica / ethylene glycol dispersion is added, the polyester low polymer is likely to be solidified due to a decrease in temperature, and it takes time for remelting. If it exceeds ℃, the aggregation of silica is liable to occur due to the temperature difference between the polyester low polymer and the silica / ethylene glycol dispersion, so that both cannot be employed.

  In the present invention, after adding the silica / ethylene glycol dispersion to the polyester low polymer, a polycondensation reaction of the polyester low polymer is performed to obtain a polyester composition. The polycondensation reaction is not limited at all, but as an example, a polycondensation catalyst is added to the polyester low polymer, and the pressure is reduced to about 0.2 to 1.3 hPa while melting and stirring at 270 to 290 ° C. Can be performed.

  In the production of the polyester composition in the present invention, one or more of a color tone improver such as a cobalt compound, a fluorescent brightening agent, a dye and a pigment, a plasticizer and a flame retardant may be added.

  The intrinsic viscosity of the polyester composition obtained by the production method of the present invention is preferably 0.5 or more. A material having an intrinsic viscosity of less than 0.5 is not preferable because various physical, mechanical and chemical properties are inferior. On the other hand, even if the intrinsic viscosity is too high, the processing operability is deteriorated. In order to set the intrinsic viscosity of the polyester composition to 0.5 or more, the catalyst amount, polycondensation reaction temperature, polycondensation reaction time, and the like in the polycondensation reaction are set to predetermined values so as to have an arbitrary intrinsic viscosity. do it.

  In the polyester composition obtained by the production method of the present invention, the average particle size of silica present in the composition is substantially equal to the average particle size of silica to be added, and the maximum particle size is suppressed to less than 20 μm, Coarse particles due to aggregation of silica are not generated. Therefore, an increase in the filtration pressure can be suppressed when the polyester composition is formed into a film or the like.

  In addition, the polyester composition obtained by the production method of the present invention is particularly suitably used as a film, and the resulting film is excellent in surface roughness and has a good air escape property. The film forming method is not limited, but as an example, the polyester composition pellets are dried by a conventional method and supplied to a melt extruder to form an unstretched film, which is longitudinally and / or transversely. The method of extending | stretching and heat-processing and setting it as a film is mentioned. The form of the film may be a single layer or a heterogeneous multilayer. Further, the polyester composition obtained by the production method of the present invention may be used alone, or may be used by blending with another polyester composition not containing inorganic fine particles.

  Next, the present invention will be described specifically by way of examples. In addition, each measured value shown in the Example was calculated | required with the following method.

(A) Intrinsic viscosity [η]
The measurement was carried out based on a conventional method under the condition of a temperature of 20 ° C. using an equal mass mixture of phenol and ethane tetrachloride as a solvent.

(B) The average particle diameter and the maximum particle diameter of the silica used were measured by the method described above.

(C) The average particle diameter of silica in the polyester composition and the maximum particle diameter The polyester composition is dissolved using an equivalent mixture of phenol and ethane tetrachloride as a solvent, and a laser diffraction particle size distribution analyzer (SALD-2000 manufactured by Shimadzu Corporation). ).

(D) Silica content in polyester composition The polyester composition was melt-molded into a disk shape and measured using an X-ray spectrometer 3270 manufactured by Rigaku Corporation.

(E) Filtration pressure rise of the filter Using a filtration pressure tester equipped with a wire mesh filter having an average opening of 20 μm, the filtration pressure when filtration is performed at a temperature of 290 ° C. and a filtration rate of 30 g / min is measured. The pressure was increased at a pressure (MPa / h).

(F) Three-dimensional surface roughness of the film The surface roughness SRa of the center surface of the film was measured as an index of the air bleedability of the film. The larger this value is, the better the air escape property is. It measured according to JIS B-0601 method using the surface roughness measuring device SE-3AK type made from Kosaka Laboratory. The stylus diameter was 2 μmR, the stylus pressure was 10 mg, and the height magnification was 50000 times.

Example 1
A slurry of terephthalic acid and ethylene glycol (molar ratio of terephthalic acid: ethylene glycol = 1.6) is continuously supplied to an esterification reactor in which a low-polymer polyester exists, under the conditions of a temperature of 250 ° C. and a pressure of 50 hPa. The reaction was carried out to obtain a polyester low polymer having an esterification reaction rate of 95% continuously for a residence time of 8 hours. This polyester low polymer was put into a 2 ton scale polycondensation reaction can heated to 270 ° C., and 1.8 ton was substituted in the container with nitrogen. After confirming the melting of the polyester low polymer, antimony trioxide as the polycondensation catalyst is 2.0 × 10 ⁻⁴ mol per 1 mol of the acid component constituting the polyester, and trimethyl phosphate as the heat stabilizer constitutes the polyester. after 1 × 10 ^-4 mol of the acid component 1 mol of magnesium acetate as pinning agent was added so as to be 4 × 10 ^-4 mol of the acid component 1 mol of constituting the polyester, the temperature of the polyester oligomer Was stirred at 270 ° C. for 1 hour.

  Next, a silica / ethylene glycol dispersion liquid in which silica having an average particle diameter of 4.0 μm and a maximum particle diameter of 12.5 μm is added to ethylene glycol so as to be 10% by mass and dispersed uniformly is prepared, It added to the polyester low polymer of 270 degreeC so that content of the silica in a polyester composition might be 2 mass%.

  Subsequently, after confirming the melting of the polyester low polymer, the pressure was gradually decreased to 1.2 hPa or less after 1 hour. The polycondensation reaction was carried out for 2 hours with stirring under these conditions, and then discharged by a conventional method and pelletized to obtain a polyester composition having an intrinsic viscosity of 0.68.

  The pellets were dried by a conventional method, blended with polyethylene terephthalate pellets having an intrinsic viscosity of 0.59 containing no inorganic fine particles, and then melt extruded at 290 ° C. to obtain an unstretched film. Further, this unstretched film was stretched three times in the longitudinal and lateral directions at 90 ° C. and heat-treated at 220 ° C. for 10 seconds to obtain a film having a thickness of 50 μm.

Examples 2-3 and Comparative Examples 1-2
This was carried out in the same manner as in Example 1 except that the average primary particle size and the maximum primary particle size of the silica used were changed to those shown in Table 1.

Examples 4-5, Comparative Examples 3-4
It carried out like Example 1 except having changed the content of the silica in a polyester composition into the value shown in Table 1.

Examples 6-7, Comparative Examples 5-6
The same procedure as in Example 1 was performed except that the polyester low polymer temperature when adding the silica / ethylene glycol dispersion was changed to the values shown in Table 1.

Examples 8-9, Comparative Examples 7-8
The same procedure as in Example 1 was performed except that the stirring time until the silica / ethylene glycol dispersion was added after the addition of the additive was changed to the values shown in Table 1.

Examples 10-11, Comparative Examples 9-10
The same procedure as in Example 1 was performed except that the concentration of the silica / ethylene glycol dispersion was changed to the values shown in Table 1.

Comparative Example 11
A 1.8 ton polyester low polymer of terephthalic acid and ethylene glycol was charged into a 2 ton scale polycondensation reaction vessel, and the inside of the container was replaced with nitrogen, followed by heating at 270 ° C. After confirming the melting of the polyester low polymer, silica having an average particle size of 4.0 μm and a maximum particle size of 12.5 μm was introduced into ethylene glycol so as to be 10% by mass and dispersed uniformly. An ethylene glycol dispersion is prepared and added to a polyester low polymer of 270 ° C. so that the content of silica in the polyester composition is 2% by mass, and the temperature of the polyester low polymer is 270 ° C. Stir for 1 hour.

Subsequently, antimony trioxide as a polycondensation catalyst is 2.0 × 10 ⁻⁴ mol per 1 mol of the acid component constituting the polyester, and trimethyl phosphate as a heat stabilizer is 1 × per mol of the acid component constituting the polyester. 10 ⁻⁴ mol, and magnesium acetate as a pinning agent was added to 4 × 10 ⁻⁴ mol with respect to 1 mol of the acid component constituting the polyester. That is, the same procedure as in Example 1 was performed except that the addition order of the silica / ethylene glycol dispersion and the additive such as the catalyst was reversed.

  Table 1 shows the results obtained in Examples 1 to 11 and Comparative Examples 1 to 11.

  In the polyester composition obtained by the production method of the example, the average particle size of the silica in the polyester composition is equal to the average particle size of the silica in the slurry, and the maximum particle size is less than 20 μm. Coarse particles were not generated, and the increase in filtration pressure was small. Moreover, the film formed using the obtained polyester composition was excellent in surface roughness.

  On the other hand, in Comparative Example 1, the average particle diameter of silica was small, and in Comparative Example 3, the content of silica was small. Therefore, the film formed using the obtained polyester composition was inferior in surface roughness. It was. In Comparative Example 2, since the average particle diameter of silica was large, the increase in filtration pressure was large. In Comparative Example 4, since the content of silica was large, in Comparative Example 7, the stirring time until the addition of the silica / ethylene glycol dispersion was short after the addition of the additive. Therefore, in Comparative Example 10, the silica / ethylene glycol was added. Since the concentration of the dispersion liquid was high, in Comparative Example 11, the order of addition of the additive and the silica / ethylene glycol dispersion liquid was reversed, so that the dispersibility of silica deteriorated and coarse particles were formed due to aggregation, resulting in an increase in filtration pressure. It was big. In Comparative Example 5, the polyester low polymer temperature at the time of stirring was low, and in Comparative Example 9, the concentration of the silica / ethylene glycol dispersion was low. The oligomer was solidified, and it took time for remelting, which was not preferable in terms of production efficiency. In Comparative Example 6, since the polyester low polymer temperature when adding the silica / ethylene glycol dispersion was high, the aggregation of silica occurred due to the temperature difference between the polyester low polymer and the silica / ethylene glycol dispersion, and the filtration pressure was reduced. The rise was great. In Comparative Example 8, since the stirring time from the addition of the additive to the addition of the silica / ethylene glycol dispersion was long, many by-products such as thermally deteriorated products were generated during the stirring, and the increase in the filtration pressure was large. Moreover, it was not preferable in terms of production efficiency.

Claims (1)

  When producing a polyester composition having terephthalic acid as a main component as a dicarboxylic acid component and ethylene glycol as a main component as a glycol component by an esterification reaction and a polycondensation reaction, a polyester low polymer after completion of the esterification reaction, After adding the catalyst, phosphate ester and alkaline earth metal compound, stirring is performed for 0.5 to 2 hours, and then silica having an average particle size of 1 to 10 μm and a maximum particle size of less than 20 μm is added to 2 The silica / ethylene glycol dispersion containing 20% by mass is added in a state where the temperature of the polyester low polymer is 240 to 300 ° C. so that the silica contains 0.5 to 3% by mass with respect to the polyester composition, A method for producing a polyethylene terephthalate-based polyester composition, wherein a polycondensation reaction is subsequently performed.