JPH0245645B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for producing a polyester copolymer, and more specifically, to a method for producing a polyester copolymer, which has a lower melting point and an appropriate degree of crystallinity than conventional polyester copolymers. This relates to a manufacturing method. Traditionally, linear polyester copolymers have been used in a wide range of applications such as films, molded products, and fibers, but generally speaking, polyester copolymers of this type with a moderate degree of crystallinity have a high molecular weight. At the same time, they have high melting points and are not necessarily suitable for certain applications, such as hot melt adhesives, laminating binders, plastic blending agents or polyester elastomers. That is, these uses often require a polyester copolymer having a relatively low melting point and an appropriate degree of crystallinity. Generally, a polyester copolymer is composed of a dicarboxylic acid component and a glycol component, and by various combinations of these two components, it is possible to change the melting point and crystallinity of the copolymer. However, in many cases, a decrease in melting point simultaneously brings about an extreme decrease in crystallinity, and in some cases, it becomes amorphous, making it difficult to balance melting point and crystallinity. However, as a result of intensive research, the present inventors found that 1,6-hexanediol and 2-
By using a mixture of methyl-1,3-propanediol, it is possible to easily control the balance between melting point and crystallinity, resulting in a polyester copolymer that has a fairly low melting point and a moderate degree of crystallinity. It was discovered that this can be obtained, leading to the present invention. That is, the present invention provides (A) terephthalic acid or a mixture of 50 mol% or more of terephthalic acid and one or more dicarboxylic acids selected from aromatic dicarboxylic acids and aliphatic dicarboxylic acids other than terephthalic acid. and (B) a mixture of 15 to 40 mol% of 2-methyl-1,3-propanediol and 85 to 60 mol% of 1,6-hexanediol. diol, and (C) one or more high molecular weight diols selected from polyalkylene ether glycol and polycaprolactone glycol (however, in an amount such that the proportion of the high molecular weight diol component in the copolymer is 0 to 60% by weight) ), and relates to a method for producing a polyester copolymer characterized by copolymerizing. As the dicarboxylic acid component used in the present invention, terephthalic acid or its ester-forming derivative is suitable in order to maintain the thermal and mechanical strength of the obtained copolymer within a preferable range, but depending on the use, terephthalic acid or its ester-forming derivative may be used. It is also possible to use a mixture of terephthalic acid and one or more dicarboxylic acids selected from aromatic dicarboxylic acids and aliphatic dicarboxylic acids other than terephthalic acid in an amount of mol % or more. Examples of the aromatic dicarboxylic acids include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-p,p'-dicarboxylic acid, bis(p-carboxyphenyl)methane, anthracenedicarboxylic acid, ethylene bis-p -benzoic acid,
Examples include 1,4-tetramethylenebis-p-benzoic acid. In addition, examples of the aliphatic dicarboxylic acids include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecandioic acid, and further aliphatic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid. . Further, a small amount of polyhydric carboxylic acid such as trimellitic acid or pyromellitic acid may also be mixed depending on the purpose. In the present invention, the low molecular weight diol is 15 to
It is necessary to use a mixture of 40 mol % 2-methyl-1,3-propanediol with 85 to 60 mol % 1,6-hexanediol. 2-methyl-
1,3-Propanediol has one methyl group in its side chain and is an asymmetric diol in terms of its chemical structure.It makes the structure of polyester copolymers containing it as a copolymer component disordered, and improves the melting point and crystallinity. It is an extremely effective compound in reducing the degree of carbonation. Moreover, 2
Since all of the hydroxyl groups are primary, they are highly reactive and easily react with compounds having carboxyl groups, such as terephthalic acid, to form ester bonds. On the other hand, 1,6-hexanediol is a diol in which six methylene groups are bonded in a linear chain and has primary hydroxyl groups at both ends, and it easily reacts with compounds having carboxyl groups to form ester bonds. The polyester obtained by forming and reacting with a dicarboxylic acid exhibits high crystallinity. According to the present invention, the melting point and crystallinity of a polyester copolymer obtained by combining the two types of low molecular weight glycol components that exhibit contradictory tendencies as described above in terms of melting point and crystallinity can be adjusted to a desired level. It can be easily controlled within this range. 2-methyl-1,3- used in the present invention
The proportion of propanediol in the low molecular weight glycol component is 15 to 40 mol%, but if it is less than 15 mol%, the above characteristics of 2-methyl-1,3-propanediol cannot be exhibited, and the resulting The melting point and crystallinity of the polymer will become too high, and if the amount exceeds 40 mol %, the melting point and crystallinity of the resulting polyester copolymer will become too low, both of which are unfavorable. Further, in the present invention, as described above, one or more high molecular weight diols selected from polyalkylene ether glycol and polycaprolactone glycol are used as polymerization reaction components, if necessary. These polymeric diols impart properties such as abrasion resistance, impact resistance, flexibility, or elastic recovery to the resulting copolymer, which are essential properties depending on the use of the copolymer. . Examples of the polyalkylene ether glycol include diethylene glycol, triethylene glycol, or polyethylene glycol with a higher degree of polymerization, poly(1,2- and 1,3-propylene oxide) glycol, poly(tetramethylene oxide) glycol, poly( (hexamethylene oxide) glycol and copolymers thereof, and a mixture of these may be used. The number average molecular weight of these polyalkylene ether glycols is 100 to 3000, preferably 100 to 3000.
It is 2000. The above polycaprolactone glycol is produced by ring-opening polymerization of lactone using an appropriate catalyst in the presence of a low molecular weight glycol such as ethylene glycol, and its number average molecular weight is 500.
~4000, preferably 800-3000. The most preferable such lactone is ε-caprolactone, and others include enantlactone, β-propiolactone, dimethylpropiolactone, butyrolactone, γ-valerolactone, γ-caprolactone,
γ-capryrolactone, crotolactone, δ-valerolactone, δ-caprolactone, etc. can also be used, but two or more of these lactones can also be used at the same time. In the reaction of the present invention, the proportion of the high molecular weight diol component in the resulting polymer is 0 to 60% by weight, preferably 0 to 40% by weight; This is not preferred because the polymer becomes too soft. Conventionally known methods for producing polyester can be applied as they are to producing the polyester copolymer of the present invention. That is, it can be produced by either a method of directly polycondensing a dicarboxylic acid compound and a diol compound, or a method of reacting an ester-forming derivative such as a lower alkyl ester of a dicarboxylic acid or a halogen derivative with a diol compound. An example of a polycondensation method by the so-called transesterification method using a lower alkyl ester of a dicarboxylic acid is shown below.
A mixed diol consisting of hexanediol, 2-methyl-1,3-propanediol and a high molecular weight diol is subjected to an esterification exchange reaction under a nitrogen atmosphere at a temperature of about 150 to 240°C under normal pressure using a normal esterification catalyst. , after distilling methanol and adding catalysts, color inhibitors, etc. as necessary, the temperature is 5 mmHg.
Polycondensation is carried out at about 200-280°C under reduced pressure. A wide range of catalysts can be used as the catalyst, including titanium compounds such as tetramethoxytitanium, tetraethoxytitanium, tetran-propoxytitanium, tetraiso-propoxytitanium, and tetrapoxytitanium, di-n-butyl-tin-dilaurate, etc. , G-n
Examples include tin compounds such as -butyl-tin-oxide and dibutyl-tin-diacetate, and combinations of acetates such as magnesium, calcium, and zinc with antimony oxide or the above-mentioned titanium compounds. These catalysts are preferably used in an amount of 0.002 to 0.8% by weight based on the total copolymer produced. Additionally, additives such as a coloring inhibitor, a polymerization accelerator, a whitening agent, a light-fastening agent, and a crystallization accelerator can be added to the reaction mixture as required. The copolymer obtained by the method of the present invention can be used in applications for which polyester copolymers have conventionally been used, such as molding materials, film materials, adhesive materials, etc., but especially hot melt adhesives and laminates. It can be used with excellent effects in applications requiring a relatively low melting point and appropriate crystallinity, such as binders, plastic blending agents, and polyester elastomers. Below, as an example of the production method of the polyester copolymer according to the present invention, and as an example of the application of the obtained polyester copolymer, the performance when used as a hot melt adhesive is illustrated as an example. It is not limited. In addition, parts in the examples mean parts by weight, and the measured values were obtained by the following measuring method. (1) The copolymer composition was determined by analyzing the nuclear magnetic resonance spectrum of the obtained copolymer. Regarding the diol component, each diol residue constituting the copolymer is shown in mol % with respect to all diol residues, and with regard to polyalkylene ether glycol, the residue is shown in weight % with respect to the copolymer. (2) Intrinsic viscosity is a value measured at 25°C in a mixed solvent of tetrachloroethane-phenol (3 parts: 2 parts). (3) Melting point and heat of fusion were measured using a differential scanning calorimeter, and Sn was used as a reference material for the heat of fusion. (4) Adhesive strength The tensile shear adhesive strength test method (JIS K6850) of the Japanese Industrial Standards ``Adhesives'' was followed. That is,
Between aluminum plates treated according to JIS K6848,
The tensile shear adhesive strength of a test piece thermocompressed to a thickness of 100 μm at 150° C. was measured using a Tensilon UTM-500 universal testing machine manufactured by Toyo Baldwin. Example 1 69.9 parts of dimethyl terephthalate, 2-methyl-
14.6 parts of 1,3-propanediol, 44.7 parts of 1,6-hexanediol and tetrabutoxytitanium catalyst
Add 0.07 parts to a reaction vessel equipped with a double helical ribbon stirrer, and add the mixture to a reaction vessel equipped with a double helical ribbon stirrer, under normal pressure and nitrogen flow.
Heat at 180℃ for 1 hour, then at 230℃ for 2.5 hours,
89% of the theoretical amount of methanol produced was distilled off. Next, 0.08 part of tridecyl phosphorite was added to the reaction mixture, the temperature was raised to 250°C, and the pressure inside the system was reduced to 0.2 mmHg over 40 minutes, and polymerization was carried out under these conditions for 3.5 hours. The intrinsic viscosity of the obtained polyester is 0.780 dl/
The melting point was 122°C and the heat of fusion was 5.07 cal/g. In addition, the copolymerized polyester was found to contain 29 mol% of 2-methyl-1,3-propanediol and 1,6-hexanediol by nuclear magnetic resonance spectrum analysis.
It was revealed that it contained 71 mol% of diol residues. Examples 2 to 6 and Comparative Examples 1 to 2 Polymerization was carried out under exactly the same polymerization conditions as in Example 1 using the charged amounts shown in Table 1. Table 1 shows the measured values for each of the obtained polymers.

【table】

[Table] Reference Example Table 2 shows the measurement results of the tensile shear adhesive strength of the polyester copolymers obtained in the Examples and Comparative Examples.
It was shown to.

【table】 (Note) In the case of the comparative example, the thermocompression bonding temperature was 170°C.

Claims (1)

[Scope of Claims] 1 (A) Terephthalic acid or a mixture of 50 mol% or more of terephthalic acid and one or more dicarboxylic acids selected from aromatic dicarboxylic acids and fatty acid dicarboxylic acids other than terephthalic acid. (B) a dicarboxylic acid or an ester-forming derivative thereof; and (B) a dicarboxylic acid or an ester-forming derivative thereof; a molecular weight diol, and (C) one or more high molecular weight diols selected from polyalkylene ether glycol and polycaprolactone glycol (provided that the proportion of the high molecular weight diol component in the copolymer is 0 to 60% by weight) A method for producing a polyester copolymer, characterized by copolymerizing a polyester copolymer (amount).