JPH04239607A - Manufacture of polyethylenenaphthalate - Google Patents

Abstract

PURPOSE:To provide a method of manufacturing polyethylenenaphthalate which is improved in its anti-blocking property and supplied as a molding raw material stably. CONSTITUTION:The present manufacture of polyethylenenaphthalate is characterized in such a manner that dicarboxylic acid containing 2,6-naphthalene dicarboxylic acid and a hydroxy compound containing ethylene glycol are subjected to polymerization condensation in liquid phase, whereby polyethylenenaphthalate is manufactured, following this, after the polyethylenenaphthalate is molded into chips, by conducting a sharing treatment to the chips, the chip surfaces are made into roughened surfaces.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing polyethylene naphthalate, and more particularly, the present invention relates to a method for producing polyethylene naphthalate, and more specifically, the chip surface is roughened by subjecting polyethylene naphthalate chips obtained by liquid phase polycondensation to a shearing treatment. The present invention relates to a method for producing polyethylene naphthalate, which improves the blocking resistance of polyethylene naphthalate and allows it to be stably supplied as a molding raw material.

0002

TECHNICAL BACKGROUND OF THE INVENTION Polyethylene naphthalate has excellent transparency, excellent gas barrier properties, and excellent mechanical strength, so it is widely used as a material for bottles and the like.

By the way, such polyethylene naphthalate is usually supplied as chips during molding, but with polyethylene naphthalate obtained by liquid phase polycondensation, the chips may stick together due to reasons such as low crystallinity. and easy to block. For this reason, the supply stability of the raw material chips deteriorates, resulting in poor biting or entrainment of air bubbles, making molding difficult.

[0004] In order to solve such problems, conventionally,
The raw material polyethylene naphthalate obtained by liquid phase polycondensation is heated and cooled to pre-crystallize it, and then further subjected to solid phase polycondensation to increase the crystallinity of polyethylene naphthalate, thereby producing chips that are difficult to block. It was used as

However, the above-mentioned method includes a preliminary crystallization step and a solid phase polycondensation step, and the solid phase polycondensation step takes a long time, so that the production cost tends to be high.

[0006] In addition, other measures may be taken, such as adding a fluidizing lubricant or attaching a feeder to the extruder supply port to stabilize the supply of raw materials. However, in the former case, the transparency of the molded article decreases due to the addition of a fluidizing lubricant, and in the latter case, the size of the equipment increases, which is not preferable in terms of industrial production.

[0007]

OBJECTS OF THE INVENTION The present invention aims to solve the problems associated with the prior art as described above, and aims to produce polyethylene naphthalate at a low cost, which can be stably supplied as raw material chips during molding. The purpose of the present invention is to provide a method for producing polyethylene naphthalate that is water-retaining.

[0008]

Summary of the Invention The method for producing polyethylene naphthalate according to the present invention involves polycondensing a dicarboxylic acid containing 2,6-naphthalene dicarboxylic acid and a hydroxy compound containing ethylene glycol in a liquid phase. After producing polyethylene naphthalate with [η] of 0.30 to 0.80 dl/g, and then molding the polyethylene naphthalate obtained in the liquid phase polycondensation process into chips, It is characterized by roughening the chip surface by subjecting the chip to shearing treatment.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The method for producing polyethylene naphthalate according to the present invention will be explained in detail below.

In the present invention, first, polyethylene naphthalate is produced by polycondensing a dicarboxylic acid containing 2,6-naphthalene dicarboxylic acid and a hydroxy compound containing ethylene glycol in a liquid phase. During the polycondensation, the polyethylene naphthalate obtained contains a structural unit consisting of ethylene-2,6-naphthalate in an amount of 60 mol% or more, preferably 80 mol%, more preferably 90 mol%. , 2,6-naphthalene dicarboxylic acid and ethylene glycol are preferably used.

In the present invention, dicarboxylic acids other than 2,6-naphthalene dicarboxylic acid and/or hydroxy compounds other than ethylene glycol may be used in amounts of less than 40 mol %.

Examples of dicarboxylic acids other than 2,6-naphthalene dicarboxylic acid include terephthalic acid, isophthalic acid, 2,7-naphthalene dicarboxylic acid, 2,5-naphthalene dicarboxylic acid, and diphenyl-4,4'-dicarboxylic acid. acid, 4,4'-diphenyl ether dicarboxylic acid,
4,4'-diphenylsulfonedicarboxylic acid, 4,4'
- Aromatic dicarboxylic acids such as diphenoxyethanedicarboxylic acid and dibromoterephthalic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, and decanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, cyclopropanedicarboxylic acid, Alicyclic dicarboxylic acids such as hexahydroterephthalic acid, glycolic acid, hydroxycarboxylic acids such as p-hydroxybenzoic acid, p-hydroxyethoxybenzoic acid, etc. can be used.

Hydroxy compounds other than ethylene glycol include propylene glycol, trimethylene glycol, diethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, neopentylene glycol, p-xylene glycol, 1,4 -Cyclohexane dimethanol, bisphenol A, p,p-diphenoxysulfone, 1,4-bis(β-hydroxyethoxy)benzene, 2,2-bis(p-β-hydroxyethoxyphenol)propane, polyalkylene glycol, p -Phenylenebis(dimethylsiloxane), glycerin, etc. can be used.

[0014] As the hydroxy compound, a small amount of a polyfunctional compound such as trimesic acid, trimethylolethane, trimethylolpropane, trimethylolmethane, or pentaerythritol may be used, for example, in an amount of 2 mol% or less.

Furthermore, monofunctional compounds such as benzoylbenzoic acid, diphenylsulfone monocarboxylic acid, stearic acid, methoxypolyethylene glycol, and phenoxypolyethylene glycol may be used in small amounts, for example, in amounts of 2 mol % or less.

[0016] In the present invention, such a liquid phase polycondensation step specifically comprises an esterification reaction step and a polycondensation reaction step. Specifically, it is carried out as follows using a dicarboxylic acid and a hydroxy compound containing ethylene glycol.

The polycondensation reaction is carried out in the presence of a catalyst. As such a catalyst, germanium compounds such as germanium dioxide, germanium tetraethoxide, germanium tetra-n-butoxide, antimony catalysts such as antimonium trioxide, and titanium catalysts such as titanium tetrabutoxide can be used.

Among these catalysts, germanium dioxide compounds are preferably used. Further, the reaction may be carried out in the presence of a stabilizer. Such stabilizers include trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate,
Phosphate esters such as triphenyl phosphate and tricresyl phosphate, triphenyl phosphide,
Phosphite esters such as trisdodecyl phosphide and trisnonylphenyl phosphide; acidic phosphate esters and phosphorus such as methyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, dibutyl phosphate, monobutyl phosphate, and dioctyl phosphate; Acids, phosphorus compounds such as polyphosphoric acid are used.

These catalysts and stabilizers may be used in the esterification reaction step, or may be supplied to the first stage polycondensation reactor in the liquid phase polycondensation step.

[0020] dicarboxylic acid, preferably 1.02 to 1.4 mol per 1 mol of dicarboxylic acid, preferably 1.03 to 1.3 mol;
molar of the hydroxy compound to form a dicarboxylic acid hydroxy compound slurry. The slurry is continuously fed to the esterification reaction step. The esterification reaction is carried out using a device in which at least two esterification reactors are connected in series under conditions in which the hydroxy compound is refluxed, while water produced by the reaction is removed from the system in a rectification column. . The reaction conditions for carrying out the esterification reaction are such that the temperature of the first stage esterification reaction is usually 21
0 to 250°C, preferably 210 to 250°C, and the pressure is usually 0.2 to 3 Kg/cm2G, preferably 0.5 to 250°C.
2Kg/cm2G, and the temperature of the final stage esterification reaction is usually 220-260℃, preferably 240-260℃.
The temperature is 60°C, and the pressure is usually 0 to 1.5 kg/cm2G, preferably 0 to 1.3 kg/cm2G. Therefore, when carrying out the esterification reaction in two stages, the first
The esterification reaction conditions of the first stage and the second stage are within the above-mentioned ranges, and when the reaction is carried out in three or more stages, the second stage is
The reaction conditions for the esterification reaction from the first stage to one stage before the final stage are between the reaction conditions for the first stage and the reaction conditions for the final stage. For example, when the esterification reaction is carried out in three stages, the temperature of the second stage esterification reaction is usually 215-255°C, preferably 235-255°C, and the pressure is usually 0-2Kg/cm2G, preferably is 0.
It is 2 to 1.5 Kg/cm2G. The reaction rate of these esterification reactions is not particularly limited in each stage, but it is preferable that the degree of increase in the esterification reaction rate in each stage is distributed smoothly, and that In the reaction product, it is usually desirable to reach 90% or more, preferably 93% or more. A lower condensate is obtained by these esterification steps, and the number average molecular weight of the lower condensate is usually 500 to 5,000.

The low-order condensate thus obtained is continuously supplied to a polycondensation reactor for the next liquid phase polycondensation step. The reaction conditions for the polycondensation reaction are such that the reaction temperature for the first stage polycondensation is usually 240 to 290°C, preferably 240 to 270°C.
The temperature is 0°C, more preferably 250-270°C, and the pressure is usually 500-20 Torr, preferably 200-30 Torr.
rr, and the temperature of the final stage polycondensation reaction is usually 2
The temperature is 50-300°C, preferably 260-290°C, and the pressure is usually 10-0.1 Torr, preferably 5-0.1 Torr.
It is 5 Torr.

When carrying out the polycondensation reaction in two stages,
The polycondensation reaction conditions for the first stage and the second stage are within the above ranges, and when carried out in three or more stages, the polycondensation reaction conditions for the second stage are
The reaction conditions of the polycondensation reaction from the first stage to one stage before the final stage are between the reaction conditions of the first stage and the final stage. For example, when the polycondensation reaction is carried out in three stages, the reaction temperature of the second stage polycondensation reaction is usually 25
The temperature is 0 to 290°C, preferably 250 to 280°C, more preferably 260 to 280°C, and the pressure is usually 50 to 2T.
orr is preferably 40 to 5 Torr.

Although there is no particular restriction on the intrinsic viscosity [η] reached in each of these polycondensation reaction steps, it is preferable that the degree of increase in the intrinsic viscosity at each stage is distributed smoothly.

In the liquid phase polycondensation process as described above, the esterification reaction can be carried out in the presence of the following basic compounds. Examples of such basic compounds include tertiary amines such as trimethylamine, tri-n-butylamine, and benzyldimethylamine, and quaternary ammonium compounds such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide, and trimethylbenzylammonium hydroxide. , lithium carbonate, sodium carbonate,
Examples include potassium carbonate and sodium acetate.

The method of adding these basic compounds is as follows:
There is no particular limitation, and it may be added to all of the esterification reactors, or may be added to a specific reactor from the first stage or the second stage.

[0026] By using the basic compound as described above, the amount of dioxyethylene terephthalate component units present can be maintained at a relatively low level in the main chain forming the resulting polyethylene terephthalate.

In the liquid phase polycondensation of polyethylene naphthalate as described above, the intrinsic viscosity [η] of the polyethylene naphthalate obtained from the final stage polycondensation reactor is usually preferably 0.2 to 0.8 dl/g. is 0.3~0.7d
l/g.

The above-mentioned intrinsic viscosity [η] is determined as follows. Polyethylene naphthalate is dissolved in o-chlorophenol at a concentration of 1 g/100 ml,
Measure the solution viscosity using an Ubbelohde capillary viscometer at 25°C, then gradually add o-chlorophenol, measure the solution viscosity on the low concentration side, and increase the concentration to 0% to determine the intrinsic viscosity. Find [η].

[0029] Furthermore, the glass transition temperature is usually 80 to 130
℃, preferably 100 to 120℃. Polyethylene naphthalate obtained by liquid phase polycondensation as described above is cooled to produce chips.

In the present invention, the chip surface is roughened by subjecting the chip made of polyethylene terephthalate obtained as described above to shearing treatment. Such shearing treatment can be performed, for example, by applying shearing stress to the chip surface. To apply shear stress to the chip surface, the chips may be agitated, for example, by rubbing a plurality of chips against each other.

[0031] The stirring device used for this purpose is
It is not particularly limited as long as it can apply shear stress to the chips, for example, Henschel mixer, V
Examples include blenders, ribbon blenders, and tumbler blenders.

[0032] The shearing treatment time is usually 3 to 20 minutes. The polyethylene naphthalate chip subjected to the shearing treatment as described above has a roughened chip surface. The degree of surface roughening is determined by surface roughness Ra measured according to JIS B 0601-1982.

Specifically, the surface roughness Ra is determined as follows. After applying shear to the chip for a predetermined period of time according to the method described in Example 1, the surface roughness was determined according to the method described in JIS B 0601-1982. The measurements were carried out using a Mitutoyo Surftest 401 surface roughness meter in a constant temperature and humidity room at 23°C and 50%, with a range of 25 μm and a λc of 0.25 m.
m, and the measured value is shown as the average value of three measured values.

In the shearing treatment, Ra'-Ra is 0, where the surface roughness of the chip before shearing treatment is Raμm and the surface roughness of the chip after shearing treatment is Ra'μm.
．． It is preferable to apply the coating so that the thickness is 2 μm or more.

[0035] In the present invention, by roughening the surface of the chips as described above, the chips become difficult to stick to each other during the drying process of the chips performed after shearing treatment, etc.
Blocking is less likely to occur.

As described above, shearing the chip has the effect that the chip surface is not only roughened but also crystallized. In the present invention, it is preferable to dry the chip whose surface has been roughened as described above at a temperature of 150° C. or higher under reduced pressure.

The polyethylene naphthalate chips obtained as described above have excellent blocking resistance.

[0038]

[Effects of the Invention] When polyethylene naphthalate obtained by the production method according to the present invention is supplied as a raw material in chips, the chips do not stick together.
It can be stably supplied to molding machines, etc.

In the production method of the present invention, polyethylene naphthalate that is less likely to cause blocking when made into chips can be obtained through a conventional preliminary crystallization step, even though it does not include a step of increasing crystallinity. For this reason,
When supplied as a molding material, it does not easily contain air bubbles, has excellent supply stability, and has good penetration. Furthermore, since the above-mentioned molding properties can be obtained without solid-phase polycondensation, it is also excellent in economical efficiency.

[0040] The present invention will be explained below with reference to Examples.
The invention is not limited to this example.

[0041]

[Example 1] Polyethylene naphthalate resin having the following physical properties was produced from 2,6-naphthalene dicarboxylic acid and ethylene glycol through an esterification process and a polycondensation reaction.
I gained kg. The glass transition point (Tg) is 118℃, the melting point (T
m) was 267°C, and the heating crystallization temperature (Tc) was 215°C.

The polyethylene naphthalate obtained as described above had an intrinsic viscosity [η] of 0.55 dl/g. This polyethylene naphthalate is made into chips,
5 kg each of the chips were mixed in a Henschel type mixer (capacity 9 liters, manufactured by Mitsui Miike Seisakusho Co., Ltd.; model FM10).
B), using a standard type impeller, the number of revolutions is 148.
Shearing treatment was performed by stirring at 0 rpm for 10 minutes. At this time, Ra'-Ra of the chip was 0.34 μm. Ra=0.14 μm.

[0043] The chip after the treatment was dried at 150°C under vacuum and used as a sample. The sample was supplied to Meiki M-70B manufactured by Meiki Seisakusho Co., Ltd.
．． Preform for 5 liter carbonated bottle at resin temperature of 30
The molding was performed at 0 to 310°C, and the incidence of molded products containing air bubbles in the preform was investigated.

[0044] The preforms were molded continuously, and a total of 30
Although 0 preforms were made, a total of 4 preforms contained air bubbles, and the occurrence rate was 1.3%.

[0045]

Comparative Example 1 Chips were obtained in the same manner as in Example 1, except that no shearing treatment was performed. The chips were dried under vacuum at 150° C., and the number of preforms with bubbles among 300 chips was counted. A total of 91 preforms had bubbles, and the occurrence rate was 30%.

Claims (3)

[Claims] Claim 1: Polyethylene naphthalate is produced by polycondensing a dicarboxylic acid containing 2,6-naphthalene dicarboxylic acid and a hydroxy compound containing ethylene glycol in a liquid phase, and then by the liquid phase polycondensation. A method for producing polyethylene naphthalate, which comprises forming the obtained polyethylene naphthalate into chips, and then subjecting the chips made of the polyethylene naphthalate to a shearing treatment to roughen the chip surface. [Claim 2] The intrinsic viscosity [η] of polyethylene naphthalate obtained by polycondensation is 0.30 to 0.80 dl/g.
The method for producing polyethylene naphthalate according to claim 1. 3. When the surface roughness of the chip before the shearing treatment is Ra μm and the surface roughness of the chip after the shearing treatment is Ra′ μm, Ra′−Ra is 0.2 μm.
The method for producing polyethylene naphthalate according to claim 1 or 2, characterized in that the chip surface is roughened so as to achieve the above.