JPH0354249A - Production of polyester resin composition - Google Patents

Abstract

PURPOSE:To obtain a nonblocking chipped polyester resin composition by mixing PET with a specified copolyester in a specified ratio, melting the mixture, cooling the melt, forming the solid product into chips, roughening the surfaces of the chips and vacuum-drying them. CONSTITUTION:A copolyester resin comprising dicarboxylic acid component units (A) comprising 20-100mol% isophthalic acid component units and 80-0mol% terephthalic acid component units, dihydroxy compound component units (B) comprising 5-90mol% dihydroxyethoxyresorcinol component units and 95-10mol% ethylene glycol component units and 0.05-1pt.mol, per 100pts.mol component A, polyhydroxy compound component units having at least three hydroxyls is produced. 90-60wt.% this resin is mixed with 10-40wt.% polyethylene terephthalate resin, and the mixture is melted. The melt is cooled to form chips, which are agitated under a shearing force to roughen their surfaces, and the roughened chips are dried at a temperature >=100 deg.C in a vacuum to obtain a polyester resin composition.

Description

[Detailed description of the invention] Is it early stage and standing? The invention relates to a method for manufacturing a polyester resin composition,
For details, see (a) polyethylene terephthalate resin,
(b) An aromatic dibasic acid is used as a dicarboxylic acid unit, a dihydroxy compound unit consisting of a dihydroxyethoxyresorcinol unit and an ethylene glycol unit, and a polyfunctional hydroxy compound unit having at least three hydroxy groups. A polyfunctional hydroxy compound component unit, or a 1,3-bis(2-hydroxydiethoxy)benzene component unit or a 1,4-bis(2-hydroxydiethoxy)benzene component unit and an ethylene glycol component unit are used as a polyfunctional hydroxy compound component unit. A polyester resin composition comprising a copolymerized polyester resin as a compound component unit, particularly containing a high content of the latter copolymerized polyester resin, and is suitable as a masterbatch for, for example, a machining material. The present invention relates to a method for producing a polyester resin composition that can be used for.

In general, polyethylene terephthalate resin has excellent mechanical strength and transparency in addition to gas barrier properties.
It has excellent formability, such as meltability and stretchability, and is also lightweight, so it is widely used as a material for shaping containers for carbonated drinks, beer, etc.

However, containers for carbonated beverages, beer, etc. are required to have extremely high gas barrier properties in order to prevent the gas from leaking out of these beverages. A polyethylene terephthalate resin assembly has been proposed.

The present inventors have already discovered that a polyester resin composition composed of a polyethylene terephthalate resin and a copolymerized polyester resin as described below has excellent gas barrier properties as well as excellent formability. (Patent application No. 1-62 filed on January 14, 1989)
No. 62).

However, when producing such a polyester resin, polyethylene terephthalate resin is generally hygroscopic, so after drying at about 150'C, it is dry blended with the above copolymerized polyester resin and melted. On the other hand, the copolymerized polyester resin is inferior in quality and has a low glass transition point. Therefore, in order to avoid blocking between the polyethylene terephthalate resin and the copolymerized polyester resin, the polyethylene terephthalate resin must be heated at 50°. It is necessary to cool it to below C and then dry blend it with the copolymerized bonoester resin. However, cooling the polyethylene terephthalate resin as described above requires large-scale equipment, which increases the manufacturing cost of the resin composite bottom and, by extension, the manufacturing cost of the precept-shaped body. I don't get it.

On the other hand, for applications that require gas barrier properties as described above, the amount of copolymerized polyester resin in the polyester resin composition is usually about 10% by weight. If the polyester resin composition as a so-called masterbatch is manufactured as chips, the required amount of polyethylene terephthalate resin chips can be mixed with the chips and subjected to molding, so a large amount of polyethylene terephthalate resin chips can be cooled. This is not necessary, and as a result, the cost of manufacturing molded objects such as containers from resin compositions can be reduced.

However, when increasing the content of copolymerized polyester resin in the polyester resin composite material, the resin composite material is usually heated at 100°C or higher prior to shaping. During the drying process, there is a problem of chips blocking each other.

The present invention has been made in order to solve the above-mentioned problems, and is to provide a polyester resin composition as a chip made of a polyethylene terephthalate resin and a copolymerized polyester resin that does not cause blocking in the drying process prior to molding. The purpose is to provide a method for manufacturing horns.

The method for producing a polyester resin composition according to the present invention for producing a polyester resin composition comprises (a) 10 to 60 parts by weight of a polyethylene terephthalate resin, and (2) 20 to 100 mol% of isophthalic acid content units and terephthalic acid content units. A dicarboxylic acid component unit consisting of 80 to 0 mol%, and (a) dihydroxyethoxyresorcinol unit 5
~90 mol% and ethylene glycol weight unit 95-1
0 mole % of a dihydroxy compound unit, and 0.05 to 1.0 mole part of a polyfunctional hydroxy compound component unit having at least three hydroxyl groups per 100 mole parts of the dicarboxylic acid component unit, or (i) ) L3-bis(2-hydroxyethoxy)benzene unit or 1.
5 to 90 mol% of 4-bis(2-hydroxyethoxy)benzene component units and 95 to 95 mol% of ethylene glycol component units
A method for producing a polyester resin composition comprising 90 to 60% by weight of a copolymerized polyester resin consisting of 10 mol%, wherein the polyethylene terephthalate resin and the copolymerized polyester resin are mixed and melted and cooled to form chips. Thereafter, the chips are stirred while applying a shearing force to roughen the surface of the chips, and then dried under reduced pressure at a temperature of 100° C. or higher.

The polyethylene terephthalate 1 resin used in the present invention is a polyester having ethylene terephthalate structural units as its main structural units. The content of ethylene terephthalate structural units in polyethylene terephthalate resin is
Usually, it is 50 mol% or more, preferably 70 mol% or more. Polyethylene terephthalate resins containing such ethylene terephthalate structural units are usually composed of diol component units and dicarboxylic acid component units.

The dicarboxylic acid component units may contain a small amount of aromatic dicarboxylic acid component units other than terephthalic acid component units. Examples of such aromatic dicarboxylic acid component units include isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, and the like.

In the ethylene terephthalate structural unit, the terephthalic acid fractional unit is usually in the range of 50 to 100 mol%, preferably 70 to 100 mol%, and the aromatic dicarboxylic acid component units other than the terephthalic acid fractional unit are Usually 0~
50 mol%, preferably in the range of 0 to 30 mol%.

On the other hand, in the diol fractional units, the ethylene glycol fractional units are usually in the range of 50 to 100 mol%, preferably 70 to 100 mol%, and the diol component units other than the ethylene glycol component units are usually 0-50
The mole % is preferably in the range of 0 to 30 mole %. Furthermore, the polyethylene terephthalate resin may contain a polyfunctional compound component unit other than the above in an amount of 2 mol % or less as a component unit.

The polyethylene terephthalate resin used in the present invention usually has an intrinsic viscosity [η] (measured value in a mixed solvent of phenol/tetrachloroethane (weight ratio 1/1) at 25°C) of 0.5 to 1. 5 dl/g, preferably 0. 6-1. 3 dl/g, and the melting point is usually 210 to 265'C, preferably 220
-260°C, and furthermore, the glass transition point is usually in the range of 50-120°C, preferably -60-100°C.

Next, the first copolyester resin used in the present invention consists of a dicarboxylic acid fractional unit consisting of an isophthalic acid fractional unit and a terephthalic acid component unit, and a dihydroxyethoxyresorcinol fractional unit and an ethylene glycol component unit. It consists of a dihydroxy compound component unit and a polyfunctional hydroxy compound component unit having at least three hydroxy groups per 100 mole parts of the dicarboxylic acid component unit. In the first copolyester resin, the dicarboxylic acid component units include 20 to 100 mol% of isophthalic acid component units, preferably 50 to 98 mol%, and 80 to 0 mol% of terephthalic acid component units, preferably, It consists of 0.5 to 50 mol%. When the amount of isophthalic acid units in the dicarboxylic acid component units is within the above range, the resulting polyester resin composition has particularly excellent gas barrier properties.

On the other hand, in the first copolymerized polyester resin, the dihydroxy compound component unit is 5 to 90 mol%, preferably 10 to 90 mol% of the dihydroxyethoxyresorcinol component unit.
85 mol% and 95 to 10 ethylene glycol component units
mol%, preferably 15 to 90 mol%. When the dihydroxyethoxyresorcinol component unit in the dihydroxy compound component unit is less than 5 mol %, it is not preferable because it becomes difficult to suppress the generation of oligomers in the production of the copolyester resin.

On the other hand, when it exceeds 90 mol%, the rate of polycondensation decreases, which is not preferable.

Furthermore, the first copolymerized polyester resin contains 0 mole units of a polyfunctional hydroxy compound having at least three hydroxy groups per 100 mole parts of the dicarboxylic acid unit.
．． 05 to 1.0 mole part, preferably 0.05 to 1.0 mole part. 1 to 0.5 mole part. When the amount of the polyfunctional hydroxy compound unit is less than 0.05 mole part per 100 mole parts of the dicarboxylic acid component unit, for example, when processing the obtained polyester resin into a shaped body such as a container, etc. , there is a risk that thickness unevenness will occur in the molded product. but,
If it exceeds 1.0 mole part, the resulting polyester resin composition will gel and become insolubilized, which is not preferable.

Examples of such a polyfunctional hydroxy compound unit include trimethylolmethane, trimethylolethane, trimethylolpropane, etc. Trimethylolpropane is particularly preferably used in the present invention. In the present invention, as the copolymerized polyester resin, a second copolymerized polyester resin consisting of a dicarboxylic acid unit consisting of an isophthalic acid component unit and a terephthalic acid component unit and a dihydroxy compound unit can also be used. .

In this second copolymerized polyester resin, the dicarboxylic acid component unit has 20 to 10 isophthalic acid component units.
0 mol %, preferably 50-100 mol % and 80-0 mol %, preferably 50-0 terephthalic acid fraction units.
It consists of mol%.

In the dicarboxylic acid component unit, when the isophthalic acid component unit is within the above range, the resulting polyester resin has particularly excellent gas barrier properties.

On the other hand, in the second copolymerized polyester resin, dihydroxy compound? I fraction units are 13-bis(2-hydroxyethoxy)benzene fraction units or 1,4-bis(2-hydroxyethoxy)benzene fraction units 5 to 90 mol%,
Preferably, it consists of 10 to 85 mol% and 95 to 10 mol% of ethylene glycol units, preferably 15 to 90 mol%. When it is less than 5 mol% of 1.3 bis(2-hydroxyethoxy)benzene unit or 1,4-bis(2-hydroxyethoxy)henzene component unit in the dihydroxy compound component unit, in the production of copolymerized polyester resin. This is not preferable because it becomes difficult to suppress the generation of oligomers.

On the other hand, when it exceeds 90 mol%, the rate of polycondensation decreases, which is not preferable.

The first and second copolymerized polyester resins as described above used in the present invention are not particularly limited, but may be used to improve moldability and gas barrier properties of the obtained polyester resin composition into containers etc. Considering that the relative viscosity measured in 0-chlorophenol at 25°C is 0.6 dl/
g or more, particularly 0.g or more. 8-0.
It is preferably in the range of 85 dl/g.

The polyester resin composition according to the present invention is produced by first dry-blending 10 to 60% by weight of the above-mentioned polyethylene terephthalate resin and 90 to 60% by weight of the first or second copolyester resin, and then blending the resulting mixture. After melt blending, the resulting strands were cooled and cut into chips, which were stirred while applying shearing force to roughen the surface of the chips, and then heated under reduced pressure for 1 hour.
It can be obtained by drying at a temperature of 00°C or higher.

Dry blending and melt blending of polyethylene terephthalate 1 resin and copolymerized polyester resin may be carried out by conventional methods, and for example, a single screw extruder, a twin screw extruder, etc. can be used for melt blending. The temperature in the melt blend is usually in the range of 250 to 320°C, preferably in the range of 260 to 300'C.

According to the present invention, the strands obtained by melt blending are led into, for example, a water tank, cooled, cut into appropriate lengths with a strand cutter to form chips, and then stirred while applying shearing force. , to roughen the surface of the chip. This surface roughening also has the effect of partially crystallizing the polyethylene terephthalate resin in the chip.

The stirrer used for this purpose is not particularly limited as long as it can impart shear to the chips, and for example, a Henschel mixer, (1) blender, ribbon blender, tumbler blender, etc. can be used. Processing time is typically in the range of 3 to 20 minutes.

As described above, if the surface of the polyester resin composition chips is roughened and then heated and dried under reduced pressure, the polyester resin according to the present invention can be obtained! I1 get something. This drying step is carried out under vacuum at 120-1. It is preferable to consist of a preliminary drying step of drying at a temperature of 40° C. and a final drying step of drying at a temperature of 140 to 160° C. under reduced pressure. This pre-drying step also has the effect of further crystallizing the polyethylene terephthalate 1 resin in the chip.

In the present invention, in the step of roughening the chip surface, the degree of roughening is determined so that the chips do not block each other in the subsequent preliminary and final drying steps.
Selected appropriately. However, according to the present invention, as an index of the degree of surface roughening, JIS B 0601-1
The surface roughness according to 982 can be used. That is, according to the present invention, in stirring the chips, the surface roughness of the chips before stirring is Ra, and the surface roughness after shearing is R.
If a', then Ra'-Ra is 0. By applying shear so that the shearing force is 2 pm or more, it is possible to effectively prevent the chips from blocking during the drying process.

As described above, according to the present invention, polyethylene terephthalate resin and copolymerized polyester resin are mixed and melted, cooled to form chips, and then stirred while applying shearing force.
Since the surface of the chip is roughened, it is then heated under reduced pressure for 10 minutes.
Even when dried at temperatures above 0°C, the chips do not block. In particular, such a chip can be easily obtained by adjusting the surface roughness of the chip to a predetermined value after shearing.

EXAMPLES The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples in any way.

In the following, the polyethylene terephthalate resin is J135 manufactured by Mitsui Bet Resin (relative viscosity measured at 25°C in 0-chlorophenol: 0.85
dl/g), and as the copolymerized polyester resin,
The relative viscosity measured at 25'C in O-chlorophenol is 0. 85 dl/g, and the resin composition consists of dicarboxylic acid component units of 90 mol% isophthalic acid component units and terephthalic acid component units of 10 mol%, and dihydroxy compound fractional units of 111 and 15 mol% of dihydroxyethoxyresorcinol components. and 85 mol% of ethylene glycol component units, and further contained 0.3 mol parts of trimethylolbroban component units based on 100 mol parts of the dicarboxylic acid component units.

Example 1 50 parts by weight of each of the copolymerized polyester resin and polyethylene terephthalate resin J135 and 200 parts of a stabilizer
After thoroughly mixing 0 pμm in a tumbler, melt blending was carried out at a resin temperature of 270 to 290°C using a single screw extruder (P-4022A manufactured by Japan Steel Works, Dia 40kaku).

The strand extruded from the die is heated to a water temperature of 50 to 60°C.
After cooling it in a water tank, it was cut into chips using a cutter.

Next, the chips were stirred and mixed for 10 minutes at a rotational speed of 1480 rpm using a Henschel mixer (FMIOB manufactured by Mitsui Miike Seisakusho, capacity 92, equipped with standard blades).

After that, put the chips in a vat and dry them in a vacuum dryer.
Pre-crystallization was performed by drying at 120°C for about 20 hours. The chips were then dried in the same dryer for 5 minutes.
It was dried at Torr, 150''C for about 20 hours.

In these drying steps, the chips made of polyester resin did not block each other, as did the chips made only of polyethylene terephthalate resin.

Further, the moisture content in the chip was initially 3000 pμm, but after the drying, it was 50 pμm or less.

Example 2 Example 1 except that 70 parts by weight of copolymerized polyester resin and 30 parts by weight of polyethylene terephthalate resin were used.
Chips of the polyester resin composition were manufactured in the same manner as above. No chip blocking was observed during the drying process.

Example 3 Example 1 except that 90 parts by weight of copolymerized polyester resin and 10 parts by weight of polyethylene terephthalate resin were used.
Chips of polyester resin composite were manufactured in the same manner as above. In the drying process, it was observed that slight blocking occurred in the chips, but this did not cause any practical problems.

Comparative Example 1 In Example 1, after the resin composition was formed into a dip, the chips were placed in a vat and pre-crystallized at 5 Torr and 120'C in a vacuum dryer without stirring using a Henschel tanker. However, the chips fused together and formed an intact clump within the vat.

Comparative Example 2 In Example 2, after the resin composition was formed into chips, the chips were placed in a vat without stirring using a Henschel mixer, and then heated at 5 Torr and 120' in a vacuum dryer.
When pre-crystallization was carried out with C, the chips of Comparative Example 1
They fused together to a greater extent than in the vat, resulting in an intact mass within the vat.

Comparative Example 3 In Example 3, after the resin assembly was made into chips, the chips were placed in a vat without stirring using a Henschel mixer, and preliminary crystallization was performed in a vacuum dryer at 5 Torr and 120°C. Ta. The chips fused together even more significantly than in Comparative Example 2, resulting in intact clumps in the vat.

Example 4 After applying shear to the chip for a predetermined period of time according to the method described in Examples 1 to 3, the surface roughness was determined according to JIS B
0601-1982. The measurement was carried out using a Mitoyo Surftest 401 surface roughness meter in a thermostatic chamber at 23°C and 50%, with a range of 25 μm and a λc of 0.25-, and the measured values were as follows:
The average value of three measurements is shown. The results are shown in Table 1.

Claims (2)

[Claims] (1) (a) Polyethylene terephthalate resin 10-6
0% by weight, and (2) dicarboxylic acid component units consisting of 20 to 100 mol% of isophthalic acid component units and 80 to 0 mol% of terephthalic acid component units; (a) 5 to 90 mol% of dihydroxyethoxyresorcinol component units and 95 to 95 mol% of ethylene glycol component units; 10 mol% of dihydroxy compound component units, and 0.05 to 1.0 mol parts of polyfunctional hydroxy compound component units having at least three hydroxy groups per 100 mol parts of the dicarboxylic acid component units, or (a) 1 , 5 to 90 mol% of 3-bis(2-hydroxyethoxy)benzene component units or 1,4-bis(2-hydroxyethoxy)benzene component units, and 95 to 10 mol% of ethylene glycol component units. In a method for producing a polyester resin composition comprising 90 to 60% by weight of a polyester resin, the polyethylene terephthalate resin and the copolymerized polyester resin are mixed and melted, cooled to form chips, and then stirred while applying a shearing force. A method for producing a polyester resin composition, which comprises roughening the surface of the chip, and then drying the chip at a temperature of 100° C. or higher under reduced pressure. (2) When the surface roughness of the chip before shearing is Raμm and the surface roughness of the chip after shearing is Ra′μm, the chip should be adjusted so that Ra′-Ra is 0.2 μm or more. 2. The method for producing a polyester resin composition according to claim 1, wherein the surface is roughened.