JPH0776263B2 - Method for producing elastic polyester - Google Patents

Description

The present invention relates to a novel method for producing an elastic polyester having an aromatic polyester as a hard segment and an aliphatic polyester polylactone as a soft segment. More specifically, the present invention relates to a method for economically producing elastic polyester of stable quality using a twin-screw or more extruder.

<Prior Art> A polyester-polyester type block copolymer in which an aromatic polyester such as polybutylene terephthalate constitutes a hard segment and polycaprolactone constitutes a soft segment has a tensile strength, a tear strength, a bending fatigue resistance, As a thermoplastic elastomer with excellent heat resistance, it is widely used in automobile parts, electric / electronic parts, mechanical parts, etc.

This polyester polyester block copolymer type elastic polyester is produced by melt-mixing and reacting a crystalline aromatic polyester and a lactone compound, and is disclosed in JP-B-48-4116 and JP-B-52-49.
037, JP 61-281124, JP 61-28361
No. 9, JP-A-61-287922, JP-A-62-20525, JP-A-62-27425 and JP-A-62-53336.

<Problems to be Solved by the Invention> However, in the method of the above-mentioned known example, the reaction time is long, the aromatic polyester constituting the hard segment and the polylactone constituting the soft segment are partially randomized by transesterification reaction, and melting point and mechanical However, there is a problem that only an elastic polyester having a large variation in dynamic strength can be produced.

<Means for Solving the Problems> Therefore, as a result of intensive studies to solve the problems and economically obtain elastic polyester having stable quality, the present inventors have found that
The present invention has been reached.

That is, the present invention provides a method for producing an elastic polyester, which comprises feeding a crystalline aromatic polyester and a lactone compound to an extruder having two or more axes and continuously carrying out addition polymerization.

The crystalline aromatic polyester used in the present invention is a polymer having at least one kind of aromatic group and an ester bond in the main repeating unit, and includes polyethylene terephthalate, polybutylene terephthalate, poly 1,4-cyclohexylene diene. Methylene terephthalate, polyethylene 2,
6-naphthalate, polybutylene 2,6-naphthalate and the like can be mentioned, but a mixture of these polyesters or these polyesters is further added with isophthalic acid units, adipic acid, sebacic acid, dodecanedioic acid or other aliphatic dicarboxylic acid units, p- A copolyester in which oxybenzoic acid units and the like are copolymerized can also be used. Among them, polybutylene terephthalate is particularly preferably used because it has excellent crystallinity.

The relative viscosity (ηr) of the crystalline aromatic polyester used in the present invention is 0.
The value measured with a 5% polymer solution at 25 ° C. is in the range of 1.20 to 2.00, particularly preferably 1.30 to 1.80. It is preferable to use a crystalline aromatic polyester having a high degree of polymerization, that is, a high relative viscosity (ηr), because the obtained elastic polyester has a high degree of polymerization and excellent mechanical properties.

Examples of the lactone compound used in the present invention include ε-caprolactone, enanthlactone, and caprylolactone, but ε-caprolactone is particularly preferable from the viewpoint of reactivity with the crystalline aromatic polyester and the elastic properties of the elastic polyester obtained. used.

The composition ratio of the crystalline aromatic polyester and the lactone compound in the present invention is preferably 99/1 to 20/80 in terms of the weight ratio of the crystalline aromatic polyester / lactone compound from the mechanical properties of the obtained elastic polyester, and particularly, Preferably 98 / 2-30 /
70.

When an elastic polyester is produced by the addition reaction of the crystalline aromatic polyester of the present invention and a lactone compound, a catalyst may be added or the reaction may be performed without a catalyst. As the catalyst, all known catalysts for ring-opening polymerization of lactone compounds can be used, and specifically, lithium, potassium, sodium, magnesium, calcium, barium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, Examples thereof include metals such as cadmium, manganese and zirconium, organic metal compounds thereof, organic acid salts, alcoholates, alkoxides and the like. Particularly preferably, tin compounds such as diacyl stannous tin, tetraacyl stannic tin, monobutyltin oxide, dibutyltin oxide, dibutyltin dilaurate, tin tetraacetate, triisobutylaluminum, tetrabutyltitanium, tetrabutylzirconium, germanium dioxide, and three. Antimony oxide,
Cobalt acetate, etc. can be used.
You may use together 1 or more types.

As a method of adding the catalyst, a method of adding it at the time of producing the crystalline aromatic polyester in advance or a method of adding it when supplying the crystalline aromatic polyester and the lactone compound to a single-screw extruder can be adopted.

The addition amount of these catalysts is 0 to 0.3% by weight, particularly preferably 0.001 to 0.2% by weight, based on the total amount of the crystalline aromatic polyester and the lactone compound. Addition of 0.3% by weight or more is not preferable because the transesterification reaction between the crystalline aromatic polyester and the polylactone proceeds and the mechanical properties of the obtained elastic polyester are impaired.

The phosphorus compound can be added after the elastic polyester is produced by the addition reaction of the crystalline polyester of the present invention and the lactone compound. The phosphorus compound substantially deactivates or suppresses the activity of the catalyst present in the reaction system, and when the blocking reaction by the addition reaction and the transesterification reaction of the crystalline aromatic polyester and the lactone compound appropriately proceeds. It is effective to add it, and has the effect of maximally suppressing the deterioration of the physical properties of the elastic polyester due to the subsequent randomization reaction.

Typical phosphorus compounds include inorganic acids such as phosphoric acid, phosphorous acid, hypophosphorous acid, methyl phosphinic acid, ethyl phosphinic acid, isobutyl phosphinic acid, benzyl phosphinic acid, phenyl phosphinic acid, cyclohexyl. Phosphinic acids such as phosphinic acid and 4-methylphenyl phosphinic acid, methyl phosphonic acid, ethyl phosphonic acid, isopropyl phosphonate, isobutyl phosphonate, benzyl phosphonate, phenyl phosphonate, cyclohexyl phosphonate Four
-Phosphonic acids such as methylphenylphosphonic acid and their alkyls having 1 to 20 carbon atoms such as methyl, ethyl, bropyr, cyclohexyl, phenyl and benzyl;
Cycloalkyl, aryl, aralkyl esters and partial esters as well as their sodium, potassium,
Examples thereof include metal salts such as calcium and magnesium, ammonium salts, phosphine oxides such as triethylphosphine oxyside and triphenylphosphine oxide, phosphines such as tributylphosphine, triphenylphosphine, tribenzylphosphine and tricyclohexylphosphine. I can.

Among these phosphorus compounds, since they are added in a dissolved state of the elastic polyester, compounds having a high boiling point or a high decomposition point are preferably used. The addition amount of the above phosphorus compound is 1
It is effective to use 0.5 or more, particularly preferably 1.0 or more phosphorus atoms per one.

The biaxial or more extruder used in the present invention has at least a raw material supply port and a discharge port for discharging a polymer in a molten state,
The shape and the like are not particularly limited as long as they can be kneaded and extruded with two or more screws. The ratio between the screw length (L) and the diameter (D), that is, the effective screw length (L / D) and the screw shape are not particularly limited. A twin-screw extruder is preferable, and a twin-screw extruder of the same or different directions is preferably used. Particularly preferred is a co-rotating intermeshing twin-screw extruder, a typical example of which is TEX commercially available from Japan Steel Works, and the extrusion shaft is a kneading disk type and a shaft part to which a screw type paddle is fixed. The paddle consists of a fixed shaft. Here, the kneading disc type paddle is a plurality of paddles fixed to an extrusion shaft, and this paddle has a cross section in the direction perpendicular to the shaft, for example, a convex lens shape or a polygonal shape of pseudo triangle or more, and the paddle of one shaft is The tip constantly rotates with a slight clearance from the end surface of the paddle of the other shaft and the inner surface of the casing. Therefore, the material on the paddle surface is constantly renewed and has a so-called self-cleaning ability. The installation method of the extruder is not particularly limited, even if the screw shaft is installed horizontally,
The object of the present invention is not impaired even if the liquid lactone compound is installed at an angle with respect to the horizontal axis in order to prevent a short pass of the liquid lactone compound.

The method for supplying the crystalline aromatic polyester and the lactone compound to the supply ports of a twin-screw or more extruder is not particularly limited,
(1) A method of simultaneously supplying a solid-state crystalline aromatic polyester and a lactone compound from a supply port, (2) A method of supplying a solid-state crystalline polyester from a supply port and a lactone compound from a vent port, (3) A method of simultaneously supplying a crystalline aromatic aromatic polyester and a lactone compound from a supply port, (4) a method of supplying a crystalline aromatic aromatic polyester from a supply port and a lactone compound from a vent port, (5) crystal A method in which the aromatic aromatic polyester and the lactone compound are melt-mixed in advance and then supplied can be employed.

The conditions for the addition polymerization of the crystalline aromatic polyester of the present invention and the lactone compound are as follows:
At a temperature of 0 to 280 ° C, preferably 215 to 250 ° C, the residence time in the extruder is 1 to 30 minutes, preferably 3 to 20 minutes.

Further, as a method of removing the lactone compound monomer present in the polymer obtained by the addition polymerization, (1) a vent port is provided at the tip of the twin-screw or more extruder used in the addition polymerization and 50 Torr or less A method of removing the lactone compound monomer at a vacuum degree of preferably 10 Torr or less, (2) supplying the polymer obtained by the addition polymerization in a solid or molten state to a single-screw or twin-screw or more extruder having a vent port, A method of removing the lactone compound monomer at a temperature above the melting point of the polymer, a vacuum degree at the vent port, 50 Torr or less, preferably 10 Torr or less, (3) supplying the polymer obtained by addition polymerization to a reactor having a stirrer, Examples include a method of removing the lactone compound monomer by allowing the polymer to stay at a temperature above the melting point of the polymer and a vacuum degree of 50 Torr or less for 1 to 30 minutes.

In addition, the elastic polyester of the present invention has a known weather resistance such as hindered phenol-based, phosphite-based, thioether-based, amine-based antioxidants, benzophenone-based, hindered amine-based, etc. Agents, fluorine-containing polymers, silicone oils, metal stearates, metal montanates, montanate ester waxes, mold release agents such as polyethylene waxes, epoxy compounds, carbodiimide compounds, bisoxazoline compounds, acyllactam compounds, isocyanate compounds Thickeners, colorants such as dyes and pigments, titanium oxide, ultraviolet shielding agents such as carbon black, glass fibers and carbon fibers, reinforcing agents such as potassium titanate, silica, clay, calcium carbonate, calcium sulfate, Glass beads etc. Fillers, nucleating agents such as talc, flame retardants, plasticizers, adhesion aids, can be allowed to optionally contain an adhesive or the like,. Further, in order to improve the mechanical strength of the elastic polyester of the present invention, another thermoplastic polymer or thermoplastic elastomer may be contained. These additives and polymers may be blended before the addition polymerization reaction of the crystalline aromatic polyester and the lactone compound,
You may mix | blend with an elastic polyester after an addition polymerization reaction.

<Operation> In the present invention, a high-viscosity crystalline aromatic polyester and a low-viscosity lactone are used by using a biaxial or more extruder having high stirring efficiency as an addition polymerization reactor of the crystalline aromatic polyester and the lactone compound. Since the compound and the catalyst can be homogeneously mixed in a short time, a high quality elastic polyester can be obtained continuously and economically.

<Examples> The effects of the present invention will be described below with reference to Examples. All percentages and parts in the examples are by weight. Further, the relative viscosity (ηr) is a value measured at 25 ° C. in a 0.5% polymer solution using o-chlorophenol as a solvent. The surface hardness, melting point and mechanical properties of the molded products shown in Examples and Comparative Examples were measured as follows.

Molding: Using an injection molding machine with a 5 ounce injection capacity,
Cylinder temperature 240 ℃, mold temperature 80 ℃ and molding cycle 4
The ASTM No. 1 dumbbell test piece and the Izod impact test piece were injection-molded at 0 second.

Surface hardness: Using the ASTM No. 1 dumbbell test piece obtained by the above injection molding, the surface hardness was measured according to the ASTM D-2240 method.

Melting point: Measured by DSC (differential scanning calorimeter) at a temperature rising rate of 10 ° C./min.

Mechanical properties: Using the ASTM No. 1 dumbbell test piece obtained by the above-mentioned injection molding, the tensile properties were measured according to the ASTM D-638 method. Also, using the Izod impact test piece, ASTM D
The impact strength was measured according to the -256 method.

Reference Example 100 parts of terephthalic acid, 110 parts of 1,4-butanediol and 0.1 part of tetrabutyl titanate were charged into an esterification can equipped with a rectification column and a helical ribbon type stirring blade, and the reaction water was discharged while stirring to remove nitrogen. After carrying out an esterification reaction at 220 ° C. for 2 hours under atmospheric pressure, the reaction product is transferred to a polymerization vessel,
After carrying out a polymerization reaction for 2 hours under a vacuum of 250 ° C and 0.5 Torr,
A polybutylene terephthalate (A-1) was obtained by discharging in strand form in water and cutting. The relative viscosity (ηr) of the obtained polybutylene terephthalate (A-1) is
The melting point was 1.40 and the melting point was 225 ° C. Next, this polybutylene terephthalate (A-1) is subjected to solid phase polymerization at a temperature of 190 ° C. and a vacuum degree of 0.5 Torr, and the solid phase polymerization time is changed to obtain a relative viscosity (ηr) of 1.52. Polybutylene terephthalate (A-2) and polybutylene terephthalate (A-3) having a relative viscosity (ηr) of 1.73 were obtained. The melting points of polybutylene terephthalate (A-2) and polybutylene terephthalate (A-3) were both 225 ° C.

Example 1, Comparative Examples 1 and 2 15 kg / hr of polybutylene terephthalate (A-2) pellets having a relative viscosity (ηr) of 1.52 were prepared using a vibration feeder.
Then, it is supplied to the supply port 1 of the twin-screw co-rotating mesh type extruder TEX44H (inner diameter: 47 mmφ, L / D = 40) manufactured by Japan Steel Works shown in FIG. 1, and ε-caprolactone 5 kg / hr is quantified. Same with pump
It was supplied to the supply port 1 of TEX44H.

The screw arrangement has a convex lens type kneading disc paddle at the middle part and the tip near the discharge port, and the other has a screw type paddle.The cylinder part of this TEX44H is divided into 12 electric heaters. The heating is controlled, and from the one near the supply port, 190 ℃, 220 ℃,
230 ℃, 230 ℃, 230 ℃, 230 ℃, 230 ℃, 230 ℃, 230 ℃, 2
At 30 ° C, 230 ° C and 230 ° C and the die portion was set to 230 ° C, the addition reaction was carried out at a screw rotation speed of 100 rpm. At this time, carbon black powder was added from the supply port, and the average residence time was measured and found to be 7 minutes. Next, the polymer was discharged in a strand form from the die, cooled with water, and then cut to obtain an elastic polyester (B-1).

Further, polymerization was continuously carried out for 5 hours, injection molding was carried out collectively for every 1 hour, and the surface hardness was measured.

For comparison, the relative viscosity (η
r) is 1.52 polybutylene terephthalate (A-2) pellets at a rate of 15 kg / hr, and is fed to the feed port 5 of the surface renewal type continuous polymerization tank shown in FIG. 2, and ε-caprolactone is 5 kg / hr.
The hr was supplied to the supply port 5 of the same reaction tank by a metering pump. 230
Elastic polyester (B-2) by staying for 10 minutes on average
The elastic polyester (B
-3) was obtained. Table 1 shows the physical properties of the obtained elastic polyester and the surface hardness variation after continuous operation for 5 hours.

It is apparent from Table 1 that the elastic polyester of stable quality according to the present invention can be produced in a short time and has excellent mechanical properties.

Examples 2 and 3 Instead of polybutylene terephthalate (A-2) having a relative viscosity (ηr) of 1.52 in Example 1, a relative viscosity (ηr) of 1.40 was used.
Polybutylene terephthalate (A-1) and a relative viscosity (ηr) of 1.73 polybutylene terephthalate (A-)
3) was used to carry out an addition polymerization reaction in the same manner as in Example 1,
Elastic polyester (B-4) and elastic polyester (B-
5) was obtained. The physical properties are shown in Table 2.

Example 4 Instead of the polybutylene terephthalate (A-2) having a relative viscosity (ηr) of 1.52 in Example 1, a polybutylene terephthalate having a relative viscosity (ηr) of 1.16 obtained by carrying out polymerization in the same manner as in Reference Example was used. Then, the addition polymerization reaction was carried out in the same manner as in Example 1. The discharge amount of the polymer was not stable, but the surface hardness variation per hour in the continuous addition polymerization reaction of the obtained elastic polyester (B-6) for 5 hours was 59, 60, 60, 5
It was stable at 9, 60.

Example 5 Polybutylene terephthalate (A-2) pellets having a relative viscosity (ηr) of 1.52 in Example 1 were supplied at 12 kg / hr, and the amount of ε-caprolactone supplied was 8 kg / hr, which was added in the same manner as in Example 1. A polymerization reaction was performed to obtain an elastic polyester (B-7). The elastic polyester (B-7) exhibited excellent physical properties such as a surface hardness of 50 D, a melting point of 199 ° C., a tensile yield stress of 14 MPa and a tensile elongation at break of 850%.

Example 6 Elastic polyester (B-1) 100 obtained in Example 1
Part, 0.1 parts of triphenylphosphine are dry blended, and using a vented single-screw extruder equipped with a full flight screw with an inner diameter of 30 mmφ and L / D = 40, the degree of vacuum at the vent port is 10 Torr, the extrusion temperature is 230 ° C., After kneading at a screw rotation speed of 60 rpm, the mixture was discharged into water in a strand form and subjected to demonomerization (de-ε-caprolactone) and catalyst deactivation to obtain an elastic polyester (B-8).

The pellets of the obtained elastic polyester (B-8) had no monomer odor (ε-caprolactone odor), were melt-retained by DSC (differential scanning calorimeter) at 230 ° C. for 30 minutes, and then were measured for melting point. It was 215 ° C. Elastic polyester (B-
When 1) was similarly melt-retained for 30 minutes at 230 ° C. and the melting point was measured, it was 203 ° C. From this, it is clear that the addition of the phosphorus compound deactivated the catalyst and suppressed the randomization reaction by the transesterification reaction.

Example 7 Relative viscosity (ηr) 1.52 polybutylene terephthalate (A
-2) 100 parts of pellets, 0.1 part of monobutyltin oxide,
The addition polymerization reaction was carried out in the same manner as in Example 1 except that the compound containing 0.2 parts of Irganox 1330 (a hindered phenolic heat stabilizer manufactured by Ciba-Geigy), which was Dalai blended, was fed at 15 kg / hr, and the elastic polyester (B -9) was obtained. Elastic polyester (B-9) has a surface hardness of 60D, a melting point of 215 ° C,
It showed excellent physical properties such as tensile yield stress of 20 MPa and Izod impact NB.

Example 8 In Example 1, a vent port 4 was provided at an intermediate position between the kneading disc paddle of TEX44H and the kneading disc paddle, and demonomerization was performed at a vacuum degree of 5 Torr to carry out an addition polymerization reaction in the same manner as in Example 1. did. The elastic polyester (B-10) thus obtained had a surface hardness of 60 D and a melting point of 215 ° C. and had no monomer odor.

<Effects of the Invention> By producing an elastic polyester by the method of the present invention, the addition polymerization reaction time and the demonomerization time are shortened, so that an elastic polyester can be easily obtained with high efficiency by a simplified apparatus and operation. You can

Further, the elastic polyester obtained in the present invention has heat resistance,
Since it has excellent durability represented by weather resistance, rubber elasticity, and mechanical properties, it can be used in a wide range of applications such as automobile parts, electric / electronic parts, and mechanical parts.

[Brief description of drawings]

FIG. 1 shows a twin-screw extruder showing an embodiment of the present invention, and FIG. 2 shows a reactor used for comparison. 1 ... Supply port 2 ... Kneading disk zone 3 ... Screw part 4 ... Vent port 5 ... Supply port 6 ... Discharge port

Claims (2)

[Claims] 1. A method for producing an elastic polyester, which comprises feeding a crystalline aromatic polyester and a lactone compound to an extruder having two or more axes and continuously carrying out addition polymerization. 2. The method for producing an elastic polyester according to claim 1, wherein the unreacted lactone compound is continuously removed from the elastic polyester.