JPH1067848A - Production of moldable polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a moldable polyester excellent in flexibility and water resistance. SOLUTION: In producing a moldable polyester containing at least 1wt.%, based on the total weight of the entire structural units, units derived form a dimer diol, the condensation reaction is performed between a polyhydric alcohol component comprising a polyether polyol derived by the addition reaction of each of the two hydroxyl groups of the dimer diol with at least one molecule of a 2-4C alkylene oxide and a 2-4C alkylene glycol and an aromatic dicarboxylic acid or its dialkyl ester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing a polyester for molding comprising a long-chain alkylene group as one component. According to the present invention, the process is excellent in flexibility, water resistance and dyeability. Polyester is obtained with high purity.

[0002]

2. Description of the Related Art Molding polyesters represented by polyethylene terephthalate and polybutylene terephthalate have excellent mechanical properties, heat resistance and chemical resistance.
Widely used for fibers, sheets, various bottles or films. However, the above polyester has a problem that it is inferior in flexibility and impact resistance at low temperature, and further, inferior in water resistance, alkali resistance and acid resistance because the resin itself is hydrolyzable.

As a means for improving the water resistance and flexibility of a polyester for molding, there is a proposal to use a dimer diol as a part of a polyhydric alcohol (Japanese Patent Laid-Open No. 3-25 / 1991).
2419). However, dimer diols are poor in compatibility with hydrophilic compounds such as terephthalic acid and ethylene glycol, and have a low polymerization rate to polyesters.Polyesters obtained by polycondensing dimer diols with terephthalic acid together with ethylene glycol etc. Then
In addition, flexibility was insufficient. From the same viewpoint, a method using dimer acid as a component of the polyester has also been proposed (JP-A-2-263827 and JP-A-6-79776). There was a similar problem.

On the other hand, polyethylene terephthalate and polybutylene terephthalate have high crystallinity,
When used as a fiber, there is a problem in dyeability, and as a means for improving dyeability, a high-boiling glycol obtained by adding ethylene oxide to an alkylene glycol having an alkylene group having 4 to 20 carbon atoms is used as a copolymer component. It has been proposed to use it (JP-A-57-63325). However, the polyester obtained by such a method still has insufficient water resistance and flexibility.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a high-purity polyester excellent in water resistance and flexibility, which is in great demand in the field of polyester resins for molding.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. That is, the present invention relates to the production of a molding polyester containing 1% by weight or more of a unit based on dimer diol based on the total amount of all the constituent units. It is characterized by polycondensing a polyether polyol having one or more molecules of an alkylene oxide having 2 to 4 alkylene oxides and a polyhydric alcohol having an alkylene glycol having 2 to 4 carbon atoms with an aromatic dicarboxylic acid or a dialkyl ester thereof. This is a method for producing a molding polyester. Hereinafter, the present invention will be described in more detail.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the polyether polyol used in the present invention has at least one alkylene oxide having 2 to 4 carbon atoms added to each of the two hydroxyl groups of the dimer diol. It is a polyether polyol, and in terms of chemical structure, two hydroxyl groups of the dimer diol are formed into groups —O— (RO) _n —H (R
Is an alkylene group having 2 to 4 carbon atoms, and n is an integer of 1 or more). The dimer diol is a saturated aliphatic diol having 36 carbon atoms obtained by completely hydrogenating high-purity dimer acid, and is a mixture containing many geometrical isomers due to the difference in the structure of the alkylene group serving as a skeleton. . Many of the alkylene groups in the dimer diol have a branched alkyl group, and it is presumed that the alkyl group is oriented on the surface of the polyester, thereby improving the water resistance. As the dimer diol, for example, Pespol HP-10 sold by Toagosei Co., Ltd.
Commercial products such as 00 can also be used.

The alkylene oxides having 2 to 4 carbon atoms include ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), butylene oxide (hereinafter abbreviated as BO) and tetrahydrofuran (hereinafter abbreviated as THF).
Abbreviated). In the present invention, a polyether polyol having both ends hydrophilized can be obtained by adding a lower alkylene oxide having high hydrophilicity to both ends of the dimer diol. Since the polyether polyol reacts with a hydrophilic aromatic dicarboxylic acid such as terephthalic acid or isophthalic acid at a high rate, a polyester containing a designed amount of dimer diol units can be easily obtained.

PO or B is added to the hydroxyl group of the dimer diol.
In the case of adding O, the terminal of the resulting polyether polyol becomes a secondary alcohol type and the reactivity of polyesterification is low. Therefore, once PO or BO is added, EO is added to add the terminal to the terminal of the polyether polyol. Is preferably converted to a primary alcohol type. When an alkylene oxide having 5 or more carbon atoms is used, the resulting polyether polyol becomes hydrophobic, and the copolymerizability with a hydrophilic aromatic dicarboxylic acid is poor. The amount of the alkylene oxide having 2 to 4 carbon atoms to be used is 2 mol or more per 1 mol of the dimer diol, and a preferable upper limit is 20 mol per 1 mol of the dimer diol.

The addition reaction of the alkylene oxide to the dimer diol can be carried out by a commonly used method. That is, when an alkylene oxide having a three-membered ring is used, a basic catalyst such as sodium hydroxide or potassium hydroxide is used in an equimolar amount with the dimer diol in the presence of the dimer diol and heated at 70 to 90 ° C. The desired polyether polyol can be obtained by adding the alkylene oxide with stirring. When THF is used as the alkylene oxide, THF is subjected to ring-opening polymerization at about 0 ° C. in the presence of a boron trifluoride ether salt, and then the polymerization is terminated by adding a disodium salt of dimer diol. The desired polyether polyol is obtained. The preferred number average molecular weight of the polyether polyol is 600 to 3000 as a value calculated from the hydroxyl value.
It is. When the number average molecular weight of the polyether polyol is 6
If it is less than 00, flexibility and water resistance are hardly exhibited in the obtained polyester, while if it exceeds 3000, the copolymerizability of the polyether polyol is inferior.

Specific examples of the alkylene glycol having 2 to 4 carbon atoms used together with the above polyether polyol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol and 1,4-propylene glycol.
Butanediol and the like, and preferably ethylene glycol and 1,4-butanediol. In the present invention, in addition to the polyether polyol and the alkylene glycol having 2 to 4 carbon atoms, 1,6-hexanediol, 1,1
9-nonanediol, cyclohexane dimethanol, diethylene glycol and triethylene glycol may be used.

Preferred aromatic dicarboxylic acids in the present invention are terephthalic acid, isophthalic acid, phthalic acid, 2,6
-Naphthalenedicarboxylic acid and 1,5-naphthalenedicarboxylic acid; and more preferably terephthalic acid. Further, dialkyl esters of the above aromatic dicarboxylic acids can also be preferably used, and the most preferred dialkyl ester is dimethyl ester. Polyester in which the main component of the acid component is terephthalic acid has excellent mechanical strength and heat resistance, and is particularly suitable for molding. When the polyester is dyed with a cationic dye, aromatic dicarboxylic acids having a sulfonic acid salt structure such as 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid and 4-sodium sulfo-2,6-naphthalenedicarboxylic acid are used. It is preferable to copolymerize. In addition, an aliphatic or alicyclic dicarboxylic acid such as succinic acid, adipic acid, azelaic acid, sebacic acid and cyclohexanedicarboxylic acid can be used as long as the effects of the present invention are not impaired.

In the present invention, a polyester is produced by polycondensing the above polyether polyol and a polyhydric alcohol comprising an alkylene glycol having 2 to 4 carbon atoms with an aromatic dicarboxylic acid or a dialkyl ester thereof. The polyester produced in the present invention is a polyester having a unit based on dimer diol (hereinafter referred to as dimer diol residue) of 1% by weight or more based on the total amount of all the constituent units, and 15% by weight or less of dimer diol. Polyesters having residues are preferred. A polyester having a dimer diol residue ratio of less than 1% by weight is inferior in flexibility and water resistance. On the other hand, if the amount exceeds 15% by weight, the heat resistance tends to decrease. The preferred average molecular weight of the polyester is such that the intrinsic viscosity measured at 25 ° C. with a 1,1,2,2-tetrachloroethane / phenol (1/1 weight ratio) mixed solvent is 0.3 or more. The polyester having an intrinsic viscosity of less than 0.3 is inferior in mechanical strength, water resistance and alkali resistance.

The polycondensation for polyesterification can be carried out by a conventionally known method, such as a method of esterifying an aromatic dicarboxylic acid and a polyhydric alcohol followed by a polycondensation, or a method of conducting a polycondensation with an aromatic dicarboxylic acid dialkyl ester. A method of subjecting a polyhydric alcohol to transesterification followed by polycondensation can be employed. In either method, a catalyst is added to the reactor together with the carboxylic acid and alcohol, and the reaction is carried out at a normal pressure at a temperature of about 230 to 300 ° C. And condensing while removing excess diols. The end point of the reaction is the point at which the fluidity of the reactants decreases at 250 ° C. or higher. The preferred charging ratio of the aromatic dicarboxylic acid or its dialkyl ester to the polyhydric alcohol is 1: (2 to 4) in molar ratio. With respect to the charge ratio of the polyether polyol containing the aromatic dicarboxylic acid and the dimer diol residue, the charge corresponding to the content of the unit based on them in the obtained polyester was charged, while the lower alkylene glycol was charged in a large excess, and the reaction was carried out. Preferably, the excess is distilled off.

As a catalyst used in the polyesterification reaction, zinc acetate, antimony oxide, tetraisopropyl titanate, tetrabutyl titanate and the like are effective. The preferred use amount of the catalyst is about 0.01 to 0.5% by weight based on the total amount of the charged compounds. If necessary, a nucleating agent, a heat stabilizer, a light stabilizer or a filler may be added to the polyester obtained by the above method.

The polyester produced according to the present invention comprises
In addition to molding into a desired shape by injection molding, blow molding, extrusion molding, or the like, it is also possible to form fibers by spinning. For example, polyester is spun into a fiber at a temperature of 200 to 300 ° C. and a winding speed of 500 to 5000.
melt spinning at m / min.
It is performed by a method of performing a stretching treatment at 1 to 6 times.
Since the fiber obtained from the polyester containing the dimer diol component targeted by the present invention has good alkali resistance, if necessary, it can be subjected to an alkali weight reduction treatment to give a silky feeling and luster. . The alkali reduction is performed, for example, by immersing the polyester fiber in a 0.1 to 5% by weight aqueous sodium hydroxide solution at 80 ° C. to the boiling temperature for 1 to 5 hours.

The dyeing of the polyester fiber is carried out with a cationic dye after knitting by a usual method.
Specifically, the object to be dyed is immersed in an aqueous solution prepared with a dye, an organic acid, an organic acid alkali metal salt, a dyeing assistant such as a slow dyeing agent, and heated at 80 to 120 ° C. for 10 to 60 minutes. Can be dyed. The amount of the dye varies depending on the color of the finished product, but is usually about 0.01 to 5% by weight based on the material to be dyed. Hereinafter, the present invention will be described more specifically with reference to Reference Examples, Examples, and Comparative Examples. The dimer diol used in each of the following examples is Pespol HP-1000 (hereinafter referred to as DD) commercially available from Toagosei Co., Ltd.

[0018]

Reference Example 1 (Synthesis of polyether polyol A)
100.0 g of DD (0.187 mol)
And 52.4 g of a 40% aqueous solution of potassium hydroxide (0.3
74 mol) at 100 ° C. under a pressure of 5 mmHg for 3 hours.
Dehydration was performed to obtain a reaction product having a water content of about 100 ppm.
The above reactant set at a temperature of 110 to 120 ° C.
In (about 5Kg / cm^Two4) g of EO over 4 hours
(1.122 mol) was added and reacted. Then 60
° C and reduced to 10 mmHg to remove residual EO
Was. After neutralizing the reaction product with hydrochloric acid, dehydration and filtration were performed.
A hydroxyl value of 140.8 mg KOH / g (number average molecule
Amount: about 800) of polyether polyol A (hereinafter simply referred to as
143 g of polyol A). Polyol A
Is According to 1H NMR analysis, EO was detected per mole of DD.
It was found to be a 6.0 mol added polyol. Ma
It has good solubility in ethylene glycol at 25 ° C
Showed sex.

[0019]

Reference Example 2 (Synthesis of Polyol B) By the same operation as in Reference Example 1,
After addition of PO to DD and subsequent addition of EO, 9.8 moles of PO and 1 mole of E per mole of DD were added.
Polyol B having a constitution to which 4.0 mol of O was added was obtained.

[0020]

Reference Example 3 (Synthesis of Polyol C) Cooled to 0 ° C. under a nitrogen atmosphere.
Boron trifluoride diethyl ether salt 28.4 g
(0.2 mol) in 146 g (2.
03 mol) was gradually added, followed by dimer diol dinatto.
58 g (0.1 mol) of lithium were added. After that, wash with water,
By drying, a hydroxyl value of 64.0 mgKOH / g (number average
175 g of polyol C having a molecular weight of 1750) was obtained. Po
Riol C 1 H NMR analysis showed that 1 mol
Or a polyol with 16.8 moles of THF added
found.

[0021]

Examples 1 to 5 The polyether polyols obtained in Reference Examples 1 to 3, dimethyl terephthalate (hereinafter referred to as DMT), ethylene glycol (hereinafter referred to as EG), and zinc acetate as a catalyst are listed in Table 1, respectively. Into the reactor at normal pressure and under a nitrogen atmosphere at 210 ° C.
The resulting methanol was distilled off. About 4-5
After a lapse of time, when the distillation of methanol stops, antimony oxide is added, and 280 is added over 2 hours.
The temperature was raised to 1 mmHg and the pressure was reduced. Then 2-3
The reaction was continued for a time, and the reaction was stopped when the viscosity of the reaction solution was increased. Table 1 shows the DD residue content, intrinsic viscosity, glass transition point, and melting point of the obtained polyester. The results of measuring the flexibility, water resistance and alkali resistance of the polyester are shown in Table 2.

[0022]

Comparative Example 1 A polyester was produced in the same manner as in Example 2 except that dimer diol was used in place of the polyether polyol in Example 2. The physical constants and the like of the obtained polyester are as follows, and the measurement results of flexibility, water resistance and alkali resistance are as shown in Table 2. Intrinsic viscosity ───0.892 Glass transition temperature ───59 ° C Melting point ───248 ° C Content of DD residue in polyester ポ リ エ ス テ ル 10% by weight

[0023]

Comparative Example 2 Polyethylene terephthalate was produced in the same manner as in the above Example except that only DMT and EG were used as main raw materials without using polyether polyol or dimer diol. The physical constants and the like of the obtained polyester are as follows, and the measurement results of flexibility, water resistance and alkali resistance are as shown in Table 2. Intrinsic viscosity ───1.045 Glass transition temperature ───80 ° C Melting point ───253 ° C

[0024]

[Table 1]

[0025]

[Table 2]

The intrinsic viscosity, glass transition temperature, flexibility and water resistance of the polyester were measured by the following methods. (A) Intrinsic viscosity 0.25 g of the dried polyester was accurately weighed, and 50
Placed in mL volumetric flask. Furthermore, 1,1,2,2-
A mixed solution of tetrachloroethane / phenol (weight ratio 1/1) was added, and the mixture was heated to 70 ° C. and dissolved. The solution was placed in a water bath maintained at 25 ° C. to a constant temperature, filled with the solvent up to the marked line of the volumetric flask, and allowed to stand for 1 hour or more. The viscosity of this solution was measured with a viscometer (Cannon Fenske SO-90366), and the intrinsic viscosity was determined by the following equation. η = ln {(T / Tb) / C} η: Intrinsic viscosity T: Flowing time of solution Tb: Flowing time of mixed solvent C: 0.5 g / dL

(B) Glass transition point and melting point The glass transition point and melting point were measured using a DSC under a nitrogen atmosphere at a rate of temperature rise and fall of 20 ° C./min.

(C) Flexibility, water resistance and alkali resistance The polyester obtained in each example was melt-extruded at 280 ° C. and discharged in a sheet form. The film was stretched three times and 3.3 times in the horizontal direction to obtain a film having a thickness of 50 μm. Evaluation of flexibility is based on JIS
In accordance with K7127, a tensile test was performed at a predetermined temperature, and the result was indicated by an elongation at break. The water resistance was evaluated by immersing the film in boiling water for 2 weeks, drying the film sufficiently, and then measuring the tensile strength (JIS K7127). . The alkali resistance was evaluated by immersing the film in a 5% aqueous solution of sodium hydroxide maintained at 100 ° C. for 24 hours, measuring the tensile strength, and indicating the strength retention as compared with the tensile strength before immersion.

[0029]

According to the present invention, a polyester having a dimer diol residue as one component can be produced with high purity.
The polyester is extremely excellent in flexibility, water resistance and alkali resistance.

Claims (1)

[Claims] When producing a molding polyester containing 1% by weight or more of a unit based on dimer diol based on the total amount of all constituent units, each of two hydroxyl groups of dimer diol has a carbon number Polycondensation of a polyether polyol having at least one molecule of 2 to 4 alkylene oxides added thereto and a polyhydric alcohol comprising an alkylene glycol having 2 to 4 carbon atoms, and an aromatic dicarboxylic acid or a dialkyl ester thereof. Of producing polyester for molding.