JP3350646B2 - Molded product made of polyester resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin having excellent transparency and hydrolysis resistance and a molded product thereof. The polyester resin and the molded product have excellent transparency and can be re-washed. It is suitable for bottle resins and bottles that can be used repeatedly.

[0002]

2. Description of the Related Art Polyester resins represented by polyethylene terephthalate are widely used in fibers, films and the like because of their excellent mechanical properties, chemical properties and transparency. More recently, it has been widely used as beverage bottles and containers instead of vinyl chloride, which has the danger of generating dioxins by incineration.

[0003] However, many of these bottles and containers for beverages are disposable, which causes an increase in waste. Recently, as one of the measures against these problems,
It is being studied to collect, wash and reuse beverage bottles and containers. However, at the time of washing, since an alkaline washing solution is used, in polyethylene terephthalate,
Hydrolysis occurs, and the surfaces of bottles and containers are whitened, and mechanical properties such as impact resistance are reduced, so that they cannot be reused. Therefore, a polyethylene naphthalate resin having better hydrolysis resistance than polyethylene terephthalate has been studied, but the hydrolysis resistance is not sufficient.

On the other hand, there is polytetramethylene naphthalenedicarboxylate (polybutylene naphthalate) as a polyester having excellent hydrolysis resistance, and a fiber which is excellent in wet heat resistance and alkali resistance using the polyester is disclosed in
No. 8887, polytetramethylene naphthalenedicarboxylate (polybutylene naphthalate) has high crystallinity. Therefore, when a bottle or container is molded by a conventional method, it becomes white due to crystallization and becomes transparent. It is difficult to manufacture bottles and containers.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, to provide a polyester resin which is excellent in hydrolysis resistance and can be used to form transparent bottles and containers by the conventional production method. And a molded product comprising the same.

The object of the present invention is to provide a compound of the general formula

Embedded image (However, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ ,
Of R ₈ , any two are a carboxyl group, and the others are hydrogen or any group. ) Is the main dicarboxylic acid component, and 50 mol% or more of the diol component is 1,3-propanediamine.
Polyester resins Tona, characterized in that the all-
Molded products (excluding metal plate laminating films)
Can be achieved by:

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The polyester resin of the present invention has the general formula

Embedded image (However, any _{two of} R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , and R ₈ are a carboxyl group, and the others represent hydrogen or an arbitrary group.) The represented compound is the main dicarboxylic acid component. Among R _{1 to} R ₈ , the substituent other than the carboxyl group is not particularly limited as long as the hydrolysis resistance and transparency of the polyester resin are not impaired, and a small substituent such as hydrogen or a methyl group may be used. preferable. Specific examples include 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 4-methyl-2,6-naphthalenedicarboxylic acid. Naphthalenedicarboxylic acid is preferred.

[0008] More than 50 mol% of the diol component is 1,3-propanediol . When the number of atoms between two OH groups is 2 or less, the polyester resin does not have sufficient hydrolysis resistance. When the number of atoms between two OH groups is 4, sufficient hydrolysis resistance is not obtained. However, it has high crystallinity and cannot obtain a transparent polyester. Further, when the number of atoms between two OH groups is 5 or more, the glass transition temperature of the obtained polyester is too low and it is difficult to use as a molded article.

The polyester resin of the present invention may be copolymerized with a diol component other than the above as the diol component, but the proportion is 50 mol% or less based on all diol components. If it exceeds 50 mol%, sufficient hydrolysis resistance,
It does not become a polyester resin having transparency and glass transition temperature. Examples of copolymerizable diol components include, for example,
Ethylene glycol, tetramethylene glycol, 1,
Aliphatic diols such as 2-propanediol, 1,3-butanediol and neopentyl glycol; alicyclic diols such as 1,4-cyclohexanedimethanol and tricyclodecanedimethylol; bisphenol A, bisphenol S, tetrabromobisphenol And aromatic ethylene diols such as A and ethylene oxide adducts thereof, dimer diols and ethylene oxide adducts thereof, and the like.

Further, the polyester of the present invention can partially convert a dicarboxylic acid component to another dicarboxylic acid component within a range that does not impair hydrolysis resistance and transparency and does not extremely lower the glass transition temperature. It can be replaced. Other dicarboxylic acids include, for example, aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid; and terephthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4 '- dicarboxylic acid, diphenylether -4,
Aromatic dicarboxylic acids such as 4'-dicarboxylic acid; alicyclic dicarboxylic acids such as hexahydroterephthalic acid, decalin dicarboxylic acid, tetralin dicarboxylic acid, and 1,4-cyclohexane dicarboxylic acid; dimer acid, glycolic acid, p-oxybenzoic acid Oxy acids such as acids are exemplified.

[0011] The polyester resin of the present invention can be produced by a known polyester production method such as a known direct polymerization method or transesterification method. For example, there is a method in which a transesterification reaction using an alkyl ester of a dicarboxylic acid and a diol, or an esterification reaction using a dicarboxylic acid and a diol is performed in a nitrogen stream, and then polycondensation is performed at a high temperature under reduced pressure. A method in which the polymer obtained by the above melt polymerization is solid-phase polymerized at a temperature lower than its melting point under reduced pressure or a nitrogen stream may be combined.

The polyester resin of the present invention may contain other polyesters, other polymers or various additives as necessary. For example, inorganic particles and organic lubricants for improving the lubricity of the molded article, such as an alkali metal compound or an alkaline earth metal compound, and internal particles formed inside a polymer such as a metal compound catalyst used in the production of polyester, and the like. In addition, an antioxidant, an antistatic agent, a coloring agent, a weathering agent, and the like can be added.

The method for producing a molded article such as a container or a bottle from the polyester resin of the present invention is not particularly limited, and a conventionally known method is used. For example, as a method for producing a bottle, there is a method in which the polyester resin of the present invention is supplied to an injection molding machine to form a preform, which is heated and blow-molded. Examples of a method for producing a molded article such as a container include a method in which the polyester resin of the present invention is supplied to an extruder, extruded from a T-die to form a sheet, and the sheet is thermoformed or folded into a box shape. Can be As a method for producing a film, the polyester resin of the present invention is supplied to an extruder, extruded into a sheet from a T-die, and this is monoaxially stretched, or sequentially biaxially stretched, simultaneously biaxially stretched, or A method in which the polyester resin of the present invention is supplied to an extruder, extruded from an inflation die, and air is blown into the inside to produce (inflation method).

[0014]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The measurement and evaluation methods are shown below.

(1) Intrinsic viscosity (IV) Resin is phenol / tetrachloroethane = 60/40
(Weight ratio) and dissolved at 20 ° C.

(2) Glass transition temperature (Tg), crystallization temperature (Tc), melting point (Tm), cooling crystallization temperature (Tc ')
Heating rate 1 by DSC7 manufactured by Perkin-Elmer
The temperature is raised to 300 ° C. or 310 ° C. at 0 ° C./min,
Glass transition temperature (Tg), crystallization temperature (Tc), and melting point (Tm) were measured. Thereafter, the temperature was maintained at 300 ° C. or 310 ° C. for 5 minutes, and the temperature was lowered to 0 ° C. at 10 ° C./min, and the temperature-reducing crystallization temperature (Tc ′) was measured.

(3) Transparency of Bottle The polyester chip is supplied to an injection molding machine to form a parison for hollow molding, and the parison for hollow molding is supplied to a blow molding machine, and the bottle (internal volume: 1.5 liters) ) Was molded. The appearance of the bottle thus obtained was evaluated. ：: transparent, Δ: slightly cloudy, ×: cloudy

(4) Transparency of Container 1 A polyester chip is supplied to an extruder, and is extruded at a temperature of 260 ° C. to 290 ° C. depending on the type of resin to obtain a thickness of 3 mm.
A sheet of 00 μm was produced. A tray was formed by thermoforming the sheet. The appearance of the tray thus obtained was evaluated. ：: transparent, Δ: slightly cloudy, ×: cloudy

(5) Transparency of Container 2 A polyester chip is supplied to an extruder and extruded at a temperature of 260 ° C. to 290 ° C. depending on the type of resin to obtain a thickness of 3 mm.
A sheet of 00 μm was produced. The sheet was folded into a box to form a case. The appearance of the case thus obtained was evaluated. ：: transparent, Δ: slightly cloudy, ×: cloudy

(6) Film Transparency 1 A polyester chip was supplied to an extruder and extruded from a T-die at a temperature of 260 ° C. to 290 ° C. depending on the type of resin to produce a sheet having a thickness of 300 μm. The sheet was stretched 3.5 times × 3.5 times by simultaneous biaxial stretching to prepare a film. The appearance of the film thus obtained was evaluated. ：: transparent, Δ: slightly cloudy, ×: cloudy

(7) Film transparency 2 A polyester chip is fed to an extruder, extruded from an inflation die at a temperature of 260 ° C. to 290 ° C. depending on the type of resin, and air is blown into the film to form a 25 μm thick film. Was prepared. The appearance of the film thus obtained was evaluated. ：: transparent, Δ: slightly cloudy, ×: cloudy

(8) Hydrolysis resistance 1 2 g of polyester chips were stored in a 30% by weight aqueous solution of potassium hydroxide at room temperature, and changes in appearance after 7 days and 1 month were evaluated. ◎: no change, ○: slightly whitened, Δ: whitened, ×: partially dissolved

(9) Hydrolysis resistance 2 Among the bottles molded in (3), transparent bottles 3
After washing 10 times with a 0 wt% aqueous potassium hydroxide solution, changes in appearance were evaluated as a measure of the degree of hydrolysis. ：: no change, Δ: slight whitening, ×: whitening

(10) Hydrolysis resistance 3 Of the trays molded in (4), transparent trays 3
After washing 10 times with a 0 wt% aqueous potassium hydroxide solution, changes in appearance were evaluated as a measure of the degree of hydrolysis. ：: no change, Δ: slight whitening, ×: whitening

(11) Hydrolysis resistance 4 Among the cases molded in (5), transparent cases
After washing 10 times with a 0 wt% aqueous potassium hydroxide solution, changes in appearance were evaluated as a measure of the degree of hydrolysis. ：: no change, Δ: slight whitening, ×: whitening

(12) Hydrolysis resistance 5 Of the films prepared in (6), the transparent one was washed 10 times with a 30 wt% aqueous potassium hydroxide solution,
The appearance change was evaluated as a measure of the degree of hydrolysis. ：: no change, Δ: slight whitening, ×: whitening

(13) Hydrolysis resistance 6 Of the films prepared in (7), the transparent one was washed 10 times with a 30 wt% aqueous potassium hydroxide solution,
The appearance change was evaluated as a measure of the degree of hydrolysis. ：: no change, Δ: slight whitening, ×: whitening

Example 1 In a stainless steel autoclave, 244 parts by weight of 2,6-dimethylnaphthalate (2,6-NDCM), 1,3
167 parts by weight of -propanediol (1,3-PD) were charged, and then 0.05 parts by weight of a titanium tetrabutoxide monomer was added as a transesterification catalyst, and a transesterification reaction was performed at 220 ° C. After completion of the transesterification reaction, titanium tetrabutoxide monomer 0.16 was used as a polymerization catalyst.
After the polycondensation reaction was performed at 260 ° C. under reduced pressure, the pressure was returned to normal pressure, the contents were extruded in a gut shape, cooled with water, and a chip-shaped polyester resin was obtained using a cutter. The above-described evaluation was performed using this polyester resin. Table 1 shows the evaluation results.

Examples 2 to 10 Polyester resins were obtained in the same manner as in Example 1 except that the composition of the polyester resin was changed as shown in Table 1. Tables 1 and 2 show the evaluation results.

Comparative Example 1 In a stainless steel autoclave, 244 parts by weight of 2,6-dimethylnaphthalate, ethylene glycol (EG)
137 parts by weight were added, and then 0.10 parts by weight of manganese acetate tetrahydrate was added as a transesterification catalyst.
A transesterification reaction was performed at ℃. After completion of the transesterification reaction, 0.08 parts by weight of antimony trioxide as a polymerization catalyst,
0.06 parts by weight of trimethyl phosphate were added, and 2
After performing a polycondensation reaction at 90 ° C. under reduced pressure, the pressure was returned to normal pressure, the contents were extruded in a gut shape, cooled with water, and a chip-shaped polyester resin was obtained using a cutter. Table 3 shows the evaluation results.

Comparative Example 2 Instead of 167 parts by weight of 1,3-propanediol,
A polyester resin was obtained in the same manner as in Example 1 except that 198 parts by weight of 4-butanediol (1,4-BD) was used. Table 3 shows the evaluation results. Since this polyester had high crystallinity, the polyester chips were crystallized, and Tg and Tc were not observed. Further, the bottles, containers, and films molded from this resin were all whitened and had poor appearance.

Comparative Examples 3 and 4 A polyester resin was obtained in the same manner as in Comparative Example 1 except that the composition of the polyester resin was changed as shown in Table 2. Table 3 shows the evaluation results.

Comparative Example 5 In a stainless steel autoclave, 194 parts by weight of dimethyl terephthalate (DMT) and ethylene glycol 13 were added.
After charging 7 parts by weight, 0.10 parts by weight of manganese acetate tetrahydrate was added as a transesterification catalyst, and a transesterification reaction was performed at 230 ° C. After the transesterification reaction is completed,
As a polymerization catalyst, 0.08 parts by weight of antimony trioxide and 0.06 parts by weight of trimethyl phosphate were added.
After performing a polycondensation reaction at a temperature of 0 ° C. under reduced pressure, the pressure was returned to normal pressure, the content was extruded in a gut shape, cooled with water, and a chip-shaped polyester resin was obtained using a cutter. Table 3 shows the evaluation results.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

As is clear from the above results, it is understood that the polyester resin of the present invention can produce a molded article having excellent hydrolysis resistance and excellent transparency.

[0038]

The polyester resin of the present invention and the molded product thereof are excellent in transparency and hydrolysis resistance, and do not whiten even when washed with an alkaline washing liquid, and maintain transparency. Therefore, it is most suitable for applications such as beverage bottles that require cleaning and reuse.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-50-30994 (JP, A) JP-A-11-228714 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (4)

(57) [Claims] 1. A compound of the general formula (However, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ ,
Of R ₈ , any two are a carboxyl group, and the others are hydrogen or any group. ) Is the main dicarboxylic acid component, and 50 mol% or more of the diol component is 1,3-propanediamine.
Polyester resins Tona, characterized in that the all-
Molded products (except for metal plate laminating films)
H) . 2. The method according to claim 2, wherein the main dicarboxylic acid component is 2,2.
The compound according to claim 1, which is 6-naphthalenedicarboxylic acid.
Moldings . 3. A compound of the general formula ( However, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ ,
Of R ₈ , any two are carboxyl groups, and the other is
Represents hydrogen or any group. ) As the main dicarboxylic acid component
At least 50 mol% of the
It is made of polyester resin that is all
Bottle . 4. The method according to claim 1, wherein the main dicarboxylic acid component is 2,2.
The compound according to claim 3, which is 6-naphthalenedicarboxylic acid.
Bottle .