JPH01256519A - Copolymerized polyester having excellent crystallinity - Google Patents

Abstract

PURPOSE:To prepare a copolymerized polyester having an improved rate of crystallization without spoiling the inherent good thermal and mechanical properties, by incorporating a specified polyfunctional component besides two constitutional components. CONSTITUTION:0.01-8mol% polyfunctional component (C) having at least two functional groups selected from among carboxylic acids and alcohols and also an alkali metal salt group of a carboxylic acid as a substituent (e.g., an alkali metal salt of dimethylolpropionic acid) based on the component A is incorporated in a polyester consisting of a dicarboxylic acid component (A) wherein the main component is terephthalic acid and a glycol component (B) wherein the main component is an alkylene glycol (pref. ethylene glycol). A low rate of crystallization which has been a defect of polyethylene terephthalate as a molding material can be improved without spoiling good thermal and mechanical properties which polyalkylene terephthalate consisting of both said components A and B, especially polyethylene terephthalate, has.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a copolyester having excellent crystallization properties and suitable as a molding material.

[Conventional technology]

Polyalkylene terephthalates are of great importance as raw materials for the production of fibers, films or moldings. Among them, polyethylene terephthalate (hereinafter abbreviated as PET) is heat resistant and chemical resistant.

It is particularly suitable for manufacturing various industrial products because of its many excellent physical properties such as mechanical properties and electrical properties. However, if this PE'l' is to be made into an injection molded product and used for brush ticking purposes.

High molding temperature (approximately 140℃) in manufacturing the molded product
Also, it requires a relatively long processing time, which poses a practical problem. In other words, it is difficult to mold at such high temperatures with general molding equipment used for molding other general-purpose thermoplastic resins such as polyamide, polypropylene, polyacetal, and polybutylene terephthalate, so special molding equipment must be installed. Also, the operation for atrocities becomes complicated.

There is a disadvantage that the working efficiency is significantly reduced, and furthermore, the molding cycle becomes longer and the molding cost increases. These molding defects found in PET are due to the crystallization characteristics of PET that are different from other general-purpose resins, that is, the crystallization rate is slow, and it is important to improve this point.

Although many methods are known as means for improving the crystallization rate of PET, a method of blending a crystal nucleating agent (nucleating agent) or a crystallization promoter into PET is generally often adopted. Examples include inorganic compounds such as talc, metal oxides such as calcium oxide, and metal salts of organic carboxylic acids such as sodium benzoate and sodium stearate.
No. 29977.

Special Publication No. 47-14502@), α-olefin and α, β
- Ionic copolymers consisting of metal salts of unsaturated carboxylic acids (Japanese Patent Publication No. 45-26225 J, alkali metal salts of polycarboxylic acids (Japanese Patent Publication No. 48-4098), etc. are used as nucleating agents. JP-A-59-161427 discloses that copolymers of alkali metal salts of sulfone and polyester are effective nucleating agents for polyester compositions.

Further, JP-A No. 56-92918 discloses a method in which the terminal group of polyester is a metal salt such as a carboxylic acid.

[Problem to be solved by the invention]

However, Special Publication No. 46-29977, Special Publication No. 47-34
The method described in No. 502 does not yet sufficiently improve the crystallization rate, and further improvement of the crystallization rate is desired, and the addition of nucleating agents and crystallization promoters causes undesirable side effects. There is also the drawback that it brings about For example, among the known nucleating agents, when using an alkali metal salt of an organic carboxylic acid, which has a relatively large effect of promoting crystallization, PET
There is a problem in that the molecular weight of the molded product decreases, leading to a decrease in the mechanical properties of the molded article. Even with the method described in Japanese Patent Publication No. 45-26225, there are problems of a decrease in the mechanical strength of the molded product and deterioration of coloration during heating. Even in the method described in Japanese Patent Publication No. 48-4098, the mechanical strength of the molded product inevitably decreases.

In addition, many of the known nucleating agents have poor uniform dispersibility in polymers, resulting in molded products that are non-uniform in terms of crystallinity and inferior in terms of dimensional stability and shape stability. Become something.

In the method described in JP-A-59-161427, 1. It is difficult to obtain a significant crystallization promoting effect. Japanese Unexamined Patent Publication 1983-1992
In the method described in No. 918, a metal base such as a carboxylic acid is introduced only at the end of the molecule. Therefore, in ordinary polyester, only two at most are introduced per molecule, and it has a remarkable effect of promoting crystallization. It is difficult to obtain the polyester, and it takes a longer time than usual to obtain the polyester with a sufficiently high molecular weight.

Since it is necessary to carry out a polycondensation reaction, there is a drawback that the polymer becomes colored.

One object of the present invention is therefore to address the drawbacks of P M 'l' as a molding material without impairing the good thermal and mechanical properties characteristic of P,ET. The purpose is to improve the slow crystallization rate.

[Means to solve the problem]

The present invention is used as a constituent component of polyester.

We discovered that the main ingredients, terephthalic acid component and ethylene glycated polyester, can solve the above problems.
The present invention has now been completed.

That is, the present invention provides a polyester consisting of a dicarboxylic acid component (a), which is the main component of 2-terephthalate, and a glycol component, which is mainly an alkylene glycol having 2 to 4 carbon atoms, with a small number of functional groups selected from alcohols. The object of the present invention is to provide a copolymerized polyester having excellent crystallinity, which contains 0.01 to 8 mol % of a polyfunctional component C having two polyfunctional components C having an alkali metal base of carbonic acid as a substituent, based on component a.

The dicarboxylic acid component a in the present invention is primarily a terephthalic acid component.

A part of it, ie less than 10 mol %, may be directly replaced with a dicarboxylic acid component other than the terephthalic acid component.

Examples of dicarboxylic acid components other than terephthalic acid components include aromatic dicarboxylic acids such as inphthalic acid, phthalic acid, naphthalenedicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenyldicarboxylic acid, and adipic acid... ...Also include aliphatic or alicyclic dicarboxylic acids such as cyclohexane-1,4-dicarboxylic acid.

In the present invention, the term "glycol component mainly composed of fullylene glycol having 2 to 4 carbon atoms" refers to an ethylene glycol or tetramethylene glycol component, but a portion thereof, i.e., less than 10 mol%, is a component other than ethylene glycol component. Other glycol components may be substituted.

Examples of such glycol components include aliphatic or alicyclic glycols such as trimethylene glycol, hexamethylene glycol, neopentyl glycol, and cyclohexane-1,4-dimetatool, as well as hydroquinone, resorcinol, and bisphenol M nato (7). Aromatic glycols are also exemplified. Furthermore, oxycarboxylic acids such as oxybenzoic acid oxycarboxylic acid and human-xyethquin benzoic acid may be copolymerized.

The greatest feature of the present invention is that, in addition to the two components a and 1) above, a polyfunctional component C having an alkali metal base of carbonic acid is contained in the entire polyester as a constituent component of the polyester. The introduction of such a polyfunctional component having an alkali metal base of carboxylic acid can be achieved by introducing a polyhydric alcohol or a polyhydric carboxylic acid having at least one alkali metal base of carboxylic acid into the dicarboxylic acid component a or the glycol component, or by a reaction thereof. This can be achieved by reacting with the product and polycondensing it.

A specific example of such polyfunctional component C is carbon M3.
Above, preferably 3 to 22 aliphatic 2 alicyclic or aromatic polyoxycarboxylic acids and polycarphonic acids mono- or dialka! Jexa is used. Among these, dioxydicarboxylic acid and dioxymonocarboxylic acid are preferred, and the most preferred is the alkali metal salt of dioxymonocarboxylic acid, such as dimethyl R-luprobionic acid.

Specific examples of the polyfunctional component C other than those mentioned above include alkali metal salts of monooxydicarboxylic acids, such as tal, ponic acid, and malic acid, and alkali metal salts of monooxypolycarboxylic acids, such as citric acid. , dioxymonocarphonic acid 1
For example, alkali metal salts such as glyceric acid, 4,4-his(4-hydrocysylμhexyl)valeric acid, and 9,10-dioxyoctadecanoic acid can be used with dioxydicarboxylic acids such as tartaric acid, α, β-di Oxyglutaric acid, α, δ-dioxyadipic acid, 6,7-cyoxidotecanniic acid, 7
．． Alkali metal salts such as 8-dioxyoctadecanoic acid, croionic acid, dioxyfumaric acid, etc. are used to prepare polyoxypolycarboxylic acids, and alkali metal salts such as desoxalic acid and oxycitric acid are used to prepare 5-polycarboxylic acids such as benzenetricarboxylic acid and benzene. Examples include alkali metal salts such as tetracarboxylic acids.

These oxycarboxylic acids are non-functional such as alkyl groups! 1 may be substituted with a substituent.

The present invention is not limited to these exemplified components.

Examples of alkali metal salts include lithium salts, sodium salts, potassium salts, etc., and sodium salts are particularly preferably used.

The content of the polyfunctional component C in the polyester to achieve the object of the present invention is 0.01 to 8 mol%, more preferably 0.1% by mole based on the dicarboxylic acid component a.
~5 mol%. If it is less than 0.01 mol %, it is not substantially effective in promoting crystallization, which is the object of the present invention, while if it is added in excess of 8 mol %, mechanical properties are deteriorated, which is not preferable.

The copolymerized polyester of the present invention is produced by a known method normally used for producing polyester. Polyesters are generally prepared by raising the temperature of a mixture of reactants in the presence or absence of a catalyst under an inert gas atmosphere at atmospheric or pressurized pressure. In that case, each raw material component is used in the form of an acid or alcohol or an ester-forming derivative thereof. The temperatures employed to carry out these reactions are in the range 180<0>C to 270<0>C, preferably in the range 210<0>C to 260<0>C. After completion of this reaction, the resulting oligomer product is subjected to polycondensation. Polycondensation reaction is known as polycondensation + m. Examples of solvents are antimony, germanium, and titanium.

! 1) In the presence of compounds such as lead, cobalt, and manganese,
It is carried out at a pressure of 10wnn11g or less, preferably 11NRHQ or less, and at a temperature of 1!&a degree in the range of 270 to 30°C (1°C).Here, the addition of the polyfunctional compound for introducing the C component can be carried out at any stage during polyester production. For example, it may be added at the esterification or transesterification stage, the polycondensation stage, or it may be added after the polycondensation and the polycondensation is continued to complete the reaction.

The intrinsic viscosity of the copolymerized polyester of the present invention is 0.3 to 1.2, preferably 0.0 when measured in a mixed solvent system of equal weights of phenol and tetrachloroethane at 30°C.
．． It is in the range of 4 to 1.0. If the intrinsic viscosity is 0.3, the strength and physical properties of the polyester will deteriorate, which is undesirable, and if it exceeds 1 or 2, the melt viscosity will increase significantly,
This is particularly inconvenient in injection molding.

In the copolymerized polyester obtained in the present invention,
The polyfunctional component C is introduced into the polymer molecule by copolymerization. For example, when trifluoroacetic acid is used as a solvent for a copolyester obtained from terephthalic acid, ethylene glycol, and sodium dimethylolpropionate, 500 to IHz -'kl
In the N M Ji spectrum, in addition to the absorption that appears in k'ET, the absorption of the proton of the methyl group is 1.3.
It is observed as a singlet at the pprn position, and the proton absorption of the methyl group is similar in a sample in which the copolymerized polyester is dissolved in a solvent (equal weight 1M mixture of phenol and tetrachloroethane) and reprecipitated with methanol. In addition to this information, in the same spectrum of sodium dimethylolpropionate (solvent: trifluoroacetic acid), the absorption of the proton of the methyl group is 1.1 ppm and 1.2 ppm. CHa 11(J-UH2-C-C1h-(JHL-UH3 protons 1.1 ppm) U(JCINa CHa 110-Uliz-C-0M2-(J-1j-Ul'3)
L-CHa proton 1.2 pprn)COON
Considering that it belongs to the structure of a O CHa (-Ch, proton 1.3 ppm), sodium dimethylolpropionate in the polyester is not simply mixed or introduced at the end of the polymer, but is copolymerized. It is clear that it is incorporated into the polymer molecule as a component. However, in the copolymerized polyester of the present invention, the case where the polyfunctional component C is bonded to the terminal is not excluded.

In the copolymerized polyester of the present invention, since the alkali metal base component C, which is thought to act as a crystal nucleating agent, has already been incorporated into the polymer molecule as a constituent component of the polyester, it has a sufficient crystallization rate even when used alone. It's thick. Therefore, when used as a molding material, conventional P
It is no longer necessary to separately add a nucleating agent to promote crystallization, which was required after E 'II', and the above-mentioned problems associated with the addition of such a nucleating agent will inevitably be solved. It will be resolved.

Further, the thermal properties and mechanical properties of the copolyester of the present invention are substantially comparable to those of P E 1'.

It is preferable as a molding material.

The present invention has produced a copolyester useful as a material for molding, especially injection molding, which has significantly improved the slow crystallization rate, which is a disadvantage of PET, without impairing the thermal and mechanical properties that are characteristic of PET. Now available.

In the copolymerized polyester obtained by the present invention, a plasticizer may be added, if necessary, in order to further enhance the crystallinity of the polyester molecule at low temperatures. As such a substance, any known substance can be used as long as it functions as described above.

Examples of this include aliphatic esters of polyhydric alcohols, aromatic esters of polyhydric alcohols,
Polyhydric carbonic acid esters, polyalkylene glycols, mono- or dialkyl ethers of polyalkylene glycol, polyester diols consisting of aliphatic glycol and aliphatic dicarboxylic acid, and ring-opening polymerization of cyclic polyesters (lactones). Polyester diols, mono- or di-IJi of various polyester diols
lli aliphatic and/or aromatic carbonic acid esters,
Examples include aromatic sulfonamides, sodium aromatic sulfonates, and fluorinated polyolefins.

Among these substances, polyalkylene glycols and mono- or dialkyl ethers of polyalkylene glycols are preferably used.

Among them, the general formula % formula % () (R+, B't represents 11 or alkyl, acyl, or aroyl having 1 to 10 carbon atoms, b2 represents an alkylene group having 2 to 4 carbon atoms, and n is a number of 5 or more. ) The polyalkylene glycol represented by is preferable. Particularly preferred are substances in which hl and ridges are lower alkyl groups. For example, polyethylene glycol, polybupylene glycol, polytetramethylene glycol, and their mono- or dialkyl ethers (such as monomethyl or dimethyl ether, monoethyl or diethyl nyf/L=, monopropyl or dipropyl ether, monobutyl or dibutyl ether, etc.) ), mono- or sialylates and mono- or sialylates (eg mono-acetylate, diacetylate, mono-2-ethylhexanoate, di-2-ethylhexanoate, heptanobenzoate, dibenzoate, etc.). In the present invention, it is preferable that the polyalkylene glycol has alkyl ether at both ends, since the inherent viscosity of the polyester resin rrfi during molding is less likely to decrease.

When using monoalkyl ethers that are etherified at only one end or polyalkylene glycols that have hydroxyl groups at both ends, the inherent viscosity of the polyester resin during molding decreases significantly, so when using these, please avoid rope polymerization. It is necessary to use a high degree of polyester resin. Polyalkylene glycol (I) must have a degree of polymerization of 5 or more, and if 5 is not read, polyalkylene glycol (I) tends to stand out on the surface of the molded product, which is undesirable. The appropriate amount is 10 parts by weight or less, preferably 5 parts by weight or less, based on the weight of the copolymerized polyester]()00.More than 10 parts by weight is inappropriate because it causes noise and deteriorates the steel column of the molded product. .

It is also possible to add a crystal nucleating agent to the copolymerized polyester of the present invention in hopes of further improving the crystallization rate. Furthermore, if necessary, organic halogen-based or phosphorus-based flame retardants may be used. Particularly preferred flame retardants include poly(halogenated styrene), halogenated epoxy compounds, and the like. It is also possible to use various flame retardant aids in combination with flame retardants. Examples of flame retardant aids that can be specifically used include antimony compounds such as antimony trioxide and antimonic acid sorter, oxalic acid layers, aluminum hydroxide, zirconium oxide, and molybdenum oxide.

In the copolyester of the present invention, various additives other than the above-mentioned components for the purpose of improving properties, such as coloring agents, mold release agents, antioxidants, and ultraviolet stabilizers, are added to the extent that the effects of the present invention are not impaired. In addition, other types of polymers such as polyester resins, polyolefin resins, acrylic resins, polycarbonate resins, polyamide resins, rubber-like elastic bodies, etc. may be blended. is also possible.

The copolymerized polyester of the present invention can be molded into desired shapes such as fibers, films, sheets, bottles, containers, laminates, etc. using an injection molding machine, an extrusion molding machine, a blow molding machine, a compression molding machine, etc. I can do it.

The present invention will be explained in further detail by giving examples below.

In the present invention, all parts in the examples are based on weight Ik.

Examples 1-6 Dimethyl terephthalate (IJM'l'') 97i11S,
A reaction was carried out using 68 parts of ethylene glycol, 0.024 parts of manganese acetate, and sodium dimethylolpropionate as a modifier in the respective ratios shown in Table 1, and equipped with a stirrer, a rectification column, and a methanol distillation cooling tube. Pour into a container, 150
The methanol produced by the reaction is distilled out of the system by heating from °C to 235 °C, and the transesterification reaction is carried out. When the distillation of methanol is completed, phosphorous acid 1 is added as a stabilizer.
1.01 parts and 0.0 parts of antimony trioxide as a polycondensation catalyst.
034 parts were added. The resulting reaction mixture was transferred to a reactor equipped with a stirrer and an ethylene glycol distillation condenser,
The condensation reaction proceeded while gradually increasing the temperature from 235° C. to 285° C. and gradually lowering the pressure of the system from normal pressure to a high vacuum below the 1-threshold mg. The polycondensation reaction was terminated when a predetermined melt viscosity was reached. The excellent polymers were evaluated as follows, and the results are shown in Table 1.

The intrinsic viscosity [η] of the polymer was measured at 30° C. using a mixed solvent system of phenol and tetrachloroethane.

The crystallization rate is evaluated using Δ′1 obtained by the following method.
ΔT = 'i'cc - 'l'ch where l'CC and l'ch are measured using a differential scanning thermometer (Mettler IJ8 (j, '1'A-3000)) The measured degrees of temperature-drop crystallization and temperature-rise crystallization are shown.

Note that 'l'cc is 5 when the sample is placed in a calorimeter at 290℃.
It shows exothermic peak application when melted in a nitrogen stream for minutes and cooled at a downfall rate of 10°C/min, while 'l'ch.

Crystallization exothermic peak when the temperature is raised at a heating rate of 10°C/min for an amorphous film sample formed by heating a dry sample to a film of about 50 μm using a heat press heated to 290°C and quenching it with liquid nitrogen. Indicates temperature.

Regarding the relationship between the crystallization rate and these peak knitting patterns due to Dk3C, it can be said that the higher Tcc and the lower 'i'ch, the faster the crystallization rate, and therefore the larger Δ'l゛, the faster the crystallization rate. show.

The melting point ('l'm), which is an index of side heat property, was expressed by the crystalline melting peak obtained when the amorphous film was measured at L)8C at an increasing rate of lθ°C/min.

The tensile strength was determined by hot pressing a dry polyester sample.
The tensile strength was measured for a test piece that was formed into a substantially non-oriented and fully crystallized sheet with a thickness of rn/B, and then produced using a dumbbell die. 0.5 portion).

Regarding the polymer obtained in Example 3, it was dissolved in trifufluoroacetic acid and 500 Mliz lH-N~tli
As a result of analysis, the absorption of protons at the 1-position methyl group at 1.3 ppm was observed as a singlet. In addition, similar NMk1 analysis was performed on a sample in which the polymer was dissolved in an equibaric ft mixed solvent of phenol and tetrachloroethane and then reprecipitated with methanol. observed in intensity.

Example 7 110 parts by weight of the copolymerized polyester l obtained in Example 3 and polyethylene glycol dimethyl ether (average molecule of polyethylene glycol portion 11 (100) 3)
After drying and blending parts by weight in advance, Plastograph (
Melt-kneaded using 1'L-30 (model 10) manufactured by Brabender (conditions: 275°C, rotor speed 30 rprn)
). The superior composition was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Examples 1 to 3 P without adding sodium dimethylolpropionate
Polyester (Comparative Example 3) was obtained in the same manner as in Example 1 except that E '11' (Comparative Example 1% 2) or sodium dimethylolpropionate was used in an amount outside the range of the present invention. , and evaluated in the same manner as in Example 1. Table 1 shows the results.
It was shown to.

Comparative Example 4 A reaction was carried out in the same manner as in Example 1, except that the amount of sodium dimethyl rubrobiionate was 10 mol 9b (vs. DM'l'), which exceeded the range of the present invention.

The resulting polymer was extremely brittle and difficult to use as a molding resin.

As is clear from Table 1 below, the copolymerized polyesters according to the present invention (Examples 1 to 7) are unmodified PET (Comparative Examples 1 and 2)
Compared to the above, ΔT was very large and the crystallization rate was superior, and the 'rm was almost the same, and - the same level of excellent heat resistance was exhibited. Regarding tensile strength, it tends to decrease as the amount of component C added increases, but if the amount is within the range of the present invention, it is a practical problem. In Example 4), the tensile strength is extremely low (
Not preferred as a molding material. Note that when the amount of component 0 is too small (Comparative Example 3), ΔT does not change much from that of PET.1 The effect of improving the crystallization rate is poor.
j Still in Example 4.5 and Comparative Example 1.2 [
η] was changed by 1 and the various performances were compared. As [η] increases, crystallization tends to slow down somewhat, but in either case, the copolyester of the present invention has a high crystallization rate.

Example 8 1 part of 53 parts of copolymerized polyester obtained in Example 3, 1 part of polyethylene glycol dimethyl ether (
Average molecular weight of polyethylene glycol part: 100,032
Weight parts and phlogopite (manufactured by Kuraray, Sujirite Mica 20)
011K) 4 oijt parts were dried in advance, mixed, and put into the hopper of a 40 mφ extruder (U'l'-40-'i' manufactured by Japan Institute of Plastics Engineering), and the cylinder temperature was 250-275-275-275. ℃ (based on hopper measurement) and a die temperature f of 265° C., extrusion molding was carried out while melting and mixing to obtain a strand pellet.

The pellets were dried at 120℃ for 15 hours, cylinder humidity 240℃-260℃-275℃, nozzle fan [2
A test piece was molded using an injection molding machine (Mekkushi Resin Kogyo Seishi '880812A8E) maintained at 80°C and mold fineness of IIO°C. The bending strength (based on A8TM 1) 790), flexural modulus (based on A8TM 1) 790), and thermal deformation fineness (based on A8TM 1) 648iC$M) 8 of the test piece were measured. The results are shown in Table 2.

Example 9 In Example 8, instead of phlogopite, Merck (manufactured by Linka Ebisu,
The same procedure as in Example 8 was conducted except that Micron White 50001i) was used. The results are shown in Table 2.

Comparative Example 5 In Example 8, 54 parts by weight of PET obtained in Comparative Example 1 was used in place of the copolymerized polyester 5S @ parts, and sodium salt of ethylene/methacrylic acid copolymer (Mitsui Polymer Co., Ltd.) was used as a crystal nucleating agent. Made by Chemical ■) 1 Imilan 1707
) 4 parts by weight was used in the same manner as in Example 8. The results are shown in Table 2.

Comparative Example 6 Comparative Example 5 was carried out in the same manner as Comparative Example 5 except that talc used in Example 9 was used instead of phlogopite. The results are shown in Table 2.

The copolymerized polyester of the present invention sufficiently progresses in crystallization even when no crystal nucleating agent is used, and even when phlogopite and talc are blended, the copolymerized polyester of the present invention has a smooth and glossy surface. A molding was obtained.

In the case of i'E'l' in which sodium salt of ethylene/methacrylic acid copolymer was used as a crystal nucleating agent, a molded product with a good surface condition was similarly obtained, but the rigidity and heat resistance (thermal deformation - degree of ) was inferior to the copolymerized polyester of the present invention.

Examples 10-14 A slurry consisting of 3 parts of terephthal a('l'a)s, 36.5 parts of ethylene glycol, 11.005 parts of phosphoric acid, and 0.034 parts of antimony trioxide was passed through a stirrer, a rectification column, and 2,6 kcvc1/l (j under pressure, 24
The esterification reaction was carried out at a temperature of 5 to 255°C. Next, after the reaction yarn was brought to normal pressure for 1 hour, a polyfunctional compound having an alkali metal base as Component C shown in Table 2 was added to the reaction product in various proportions, and the reaction was further allowed to proceed for one portion. Transfer the superior reaction mixture to a polycondensator.

While gradually increasing the temperature to 280℃, the pressure of the system was decreased from normal pressure to 1 m.
The condensation reaction was carried out by lowering the temperature to t<kg or less.

The polycondensation reaction was terminated as soon as a predetermined melt viscosity was reached, that is, 55 to 70 minutes from the start of the first polycondensation reaction, and the obtained polymer was evaluated in the same manner as described above. The results are shown in Table 3. It is clear that all the copolyesters of the present invention have excellent heat resistance and a high crystallization rate.

Comparative Example 7 The reaction was carried out in the same manner as in Example 10 except that sodium monomethyl terephthalate was used as component O in an amount of 1 mol % based on the terephthalic acid component. When the polycondensation reaction time was the same as in Example 10 (65 minutes after the polycondensation reaction time), the melt viscosity was considerably lower than that in Example 10, so the polycondensation reaction was further continued, and eventually the type combination reaction started. After 110 minutes, the same melt viscosity as that of Example 10 was reached, but the polymer was colored light brown. Poor but excellent polymer ([η]-〇, 53)
(1) The improvement in crystallization rate compared to JTLt 50 TE was not significant.

As described above, [Effects of the Invention] The present invention provides a copolyester suitable as a molding material having excellent crystallization properties.

Claims (1)

[Scope of Claims] 1) A polyester consisting of a dicarboxylic acid component (a) mainly consisting of terephthalic acid and a glycol component (b) mainly consisting of an alkylene glycol having 2 to 4 carbon atoms, comprising: a functional group selected from carboxylic acids or alcohols; The polyfunctional component c containing at least two groups and having an alkali metal base of a carboxylic acid as a substituent is added to component a in an amount of 0.
A copolymerized polyester with excellent crystallinity containing 01 to 8 mol%. 2) At least 90 mol% of dicarboxylic acid component a
The copolymerized polyester according to claim 1, wherein is a terephthalic acid component, and at least 90 mol% of the glycol component b is an ethylene glycol component. 3) The copolymerized polyester according to claim 1 or 2, wherein the polyfunctional component c having an alkali metal base of a carboxylic acid is an alkali metal salt of a dioxymonocarboxylic acid. 4) The copolymerized polyester according to claim 1 or 2, wherein the polyfunctional component c having an alkali metal base of carboxylic acid is an alkali metal salt of dimethylolpropionic acid. 5) The copolymerized polyester according to any one of claims 1 to 4, wherein the proportion of the polyfunctional component c having an alkali metal base of carboxylic acid to the component a is 0.1 to 5 mol%. 6) The copolyester according to any one of claims 1 to 5, which has an intrinsic viscosity in the range of 0.3 to 1.2.