JP3117810B2 - Polyester particle mixture - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixture of polyester particles, and the dimensional accuracy of the molded product is not changed even if the mixing ratio of the dust generated during molding to the original particles is changed. The present invention relates to a particle mixture that can also reduce the occurrence of fogging.

[0002]

2. Description of the Related Art Polyesters are widely used in fibers, films, bottles, industrial resins and the like because of their excellent mechanical, physical and chemical properties.

[0003] Of these, the use for bottles has been rapidly growing in recent years because of its excellent transparency, light weight, impact strength and the like. However, since it is a packaging material, it is extremely strict in terms of cost, and it is a common sense that dust generated during molding is pulverized as it is and used as flakes or pelletized and mixed with the original particles.

[0004] Since the flakes are once melt-molded or stretch-crystallized, they exhibit a peculiar crystallization behavior as compared with the original particles, and affect the bottle size after molding. For this reason, unless the flakes ratio is controlled to be constant, the bottle height or the like fluctuates, which causes defective products. Flakes increase when the number of defective bottles increases due to a process failure, and conversely, when the process becomes stable, the flakes decrease. Therefore, the molding conditions must be adjusted each time. Beyond the adjustable range, the bottle dimensions will change and the mold will need to be changed.

[0005] In order to cope without changing the mold, it is inevitable that the good bottle is pulverized, flaked, mixed with the original particles and molded.

On the other hand, when the polyester is melt-molded, a small amount of low molecular weight oligomers, monomers and the like contained in the polyester or generated due to regeneration or decomposition during the melt-molding migrate to the surface of the molded article, There is a problem that the low molecular weight material adheres to the mold and fills the vent, or is transferred to the surface of the molded product and fogs the molded product.

Particularly, in the case of polyester obtained by solid-state polymerization of the original particles as polyester, since the molding waste flakes have undergone a melting step, the content of low molecular weight substances has increased, and the influence on molded products is great. .

Apart from recycling, a method of hydrolyzing polyester (Japanese Patent Application Laid-Open No. 56-11 / 1999) is a method for preventing low molecular weight substances in molded articles and troubles caused by molding due to the low molecular weight substances.
No. 8420) and a warm water treatment method in which the conditions are somewhat mild (JP-A-3-7725, JP-A-3-47830,
3-72523, 72524 and 3-174
No. 441) has been proposed.

Although these methods are certainly effective in regenerating low molecular weight substances and suppressing troubles caused by them, there are problems in that the amount of treatment is enormous and it is difficult to control polymer quality after the treatment.

[0010]

SUMMARY OF THE INVENTION According to the present invention, even if the amount of flakes fluctuates, the influence on the quality of molded products is extremely small.
Further, the present invention provides a mixture of polyester particles having little clouding of a molded article.

[0011]

According to the present invention, the following three kinds of particles are (B + C): A = 8-20: 92-8 in weight ratio.
0, and a polyester particle mixture in which particles C are 1% or more. However, and particles A: a polyester comprising an aromatic dicarboxylic acid and an aliphatic glycol, grain child intrinsic viscosity of 0.65~0.90dl / g, particle
B: The particle A once melt-molding, even in the grinding or pelletizing it. Particle C : hydrolyzes the particle A,
Polyester particles having an intrinsic viscosity lower by 0.01 to 0.25 dl / g than that of the particles A.

The present invention will be described.

In the present invention, the "polyester" refers to a polyester containing an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component.
Here, "main" means that dicarboxylic acid and glycol are 8
It means that it accounts for 5 mol% or more. What contains 15 mol% or less of the third component is a technique to which the present invention can be applied.

Examples of the "aromatic dicarboxylic acid" constituting the polyester include terephthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylketonedicarboxylic acid, diphenoxyethanedicarboxylic acid and the like.

Examples of the "aliphatic glycol" constituting the polyester include ethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol and the like.

The copolymerizable third component includes dicarboxylic acids other than aromatic dicarboxylic acids and aliphatic glycols constituting the polyester, diols, and oxycarboxylic acids. Specifically, in addition to the above compounds, aromatic dicarboxylic acids such as isophthalic acid, diphenylsulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, sodium-sulfoisophthalic acid, and dibromoterephthalic acid;
Alicyclic dicarboxylic acids, for example, decalin dicarboxylic acid,
Tetralin dicarboxylic acid, hexahydroterephthalic acid;
Examples thereof include aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid and sebacic acid. Examples of the glycol component include aliphatic diols such as pentamethylene glycol, diethylene glycol, and triethylene glycol; aromatic diols such as catechol, naphthalene diol, resorcinol, 4,4'-dihydroxy-diphenyl-sulfone, and bisphenol A ([ 2,
2'-bis (4-hydroxyphenyl) propane], tetrabromobisphenol A, bishydroxyethoxybisphenol A, etc .; alicyclic diols, eg, cyclohexanediol; aliphatic oxycarboxylic acids, eg, glycolic acid, hydroacrylic acid, 3 -Oxypropionic acid and the like; alicyclic oxycarboxylic acids such as asiatic acid, quinovanic acid and the like; aromatic oxycarboxylic acids such as salicylic acid, m-oxybenzoic acid, p-oxybenzoic acid, mandelic acid and atrolactin acid Can be mentioned.

Further, a polyfunctional compound having a valence of 3 or more, for example, glycerin, within a range in which the polyester is substantially linear.
Trimethylolpropane, pentaerythritol, trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, gallic acid, etc. may be copolymerized, and if necessary, monofunctional compounds such as o-benzoylbenzoic acid, naphthoic acid, etc. May be added.

In the present invention, "particles" are in the form of ordinary pellets or flakes. "pellet"
The term “square” having an average particle diameter of 1 to 4 mm or a well-shaped one such as a cylinder is used. The term "flakes" refers to an irregular shape obtained by pulverizing molding waste and the like, and is generally called "repro" or "reclaim" in the industry.

In the present invention, the particles A are so-called “virgin pellets” and have an intrinsic viscosity of 0.65 to 0.90 d.
1 / g is targeted. Particle B is a so-called "repro". Although the polymer properties are essentially the same as those of the particle A, the intrinsic viscosity and the crystal behavior are different from those of the particle A because the polymer is once melt-molded, stretched or heat-set compared to the particle A.

The particles C are obtained by hydrolyzing the polyester A. Particle C has a lower intrinsic viscosity than particle A by 0.01 to 0.25 due to hydrolysis. If the intrinsic viscosity reduction is less than 0.01, the crystallization rate of the particles A
When the amount of the particles B (repro) decreases, the size of the molded product changes. When the intrinsic viscosity lowering amount is 0.01 or more, the crystallization temperature (Tci) at the time of temperature rise becomes lower than the original polymer particle A by about 10 ° C. or more, and the intrinsic viscosity lowering amount is 0.1 ° C.
When it is 02 or more, the temperature is lowered by about 20 ° C. or more, and the crystallization becomes easy accordingly. However, when the intrinsic viscosity decrease exceeds 0.25, the physical properties of a polyester formed from a mixture of the particles A, B, and C as a molded product are deteriorated. A preferable range of the intrinsic viscosity reduction amount as the particle C is, as compared with the particle A,
0.02 to 0.20 lower.

The weight ratio of particles A, B and C is (B +
C): A = 8-20: 92-80, and the particles C
Accounts for 1% or more of the total.

If the ratio of B + C exceeds this range, the dimensional accuracy of the molded product will decrease. The object of the present invention cannot be achieved unless the proportion of the particles C accounts for 1% or more of the whole.

The preferred range is (B + C): A = 10-1
8: 90 to 82, a preferred range of C is 2% or more of the whole,
More preferably, it is at least 5%.

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples. Each characteristic used in the examples was measured by the following method.

(A) Intrinsic viscosity: [η] phenol / tetrachloroethane (weight ratio 60/40)
Was calculated from the solution viscosity measured at 35 ° C. using a mixed solvent of

(B) DEG: After hydrazinolysis, it was quantified by gas chromatography.

(C) Solution haze: An o-chlorophenol solution was prepared and measured with a haze meter.

(D) Tci: Using a differential scanning calorimeter,
The measurement was performed at a heating rate of 20 ° C./min.

(E) Bottle height: 160 particles compound
After drying at 5 ° C. for 5 hours, an injection molding machine Dynamelter M-100DM manufactured by Meiki Seisakusho Co., Ltd. was used.
A preform of 50 g is formed at 5 ° C. and blow-stretched to form a bottle having an inner volume of 1.5 liter and a wall thickness of 0.3 mm. The distance from the top surface of the four points forming 90 ° to each other in the body direction of the bottle and the lower surface of the support ring was measured, and the average value was defined as the height.

(F) Transparency of molded article: 160
After drying at 5 ° C. for 5 hours, using an injection molding machine Dynamelter M-100DM manufactured by Meiki Seisakusho, cylinder temperature 29
A preform of 50 g is formed at 5 ° C. and blow-stretched to form a bottle having an inner volume of 1.5 liter and a wall thickness of 0.3 mm. The straight body was cut out, and the haze of the bottle body was measured with a haze meter to determine the transparency of the molded product.

(G) Oligomer (abbreviated as Cy-3) Sampling was performed from a polymer or a preform of a molded bottle, and this was dissolved in a mixed solvent of hexafluoroisopropanol / chloroform (50/50), and further diluted with chloroform. The content of the cyclic trimer in the filtrate filtered with a filter is quantified using ALC / GPC244 of Waters.

Fogging caused by irregularities on the bottle surface due to the transfer of the deposits on the bottle to the bottle cannot be evaluated without continuous molding for a long period of time. Therefore, this was substituted by the increased amount of oligomer before and after molding.

[0033]

[Reference example]

(Preparation of Particle B) Teijin polyester resin TR-855
After drying 0T (intrinsic viscosity 0.76, DEG 1.5% by weight) (particle A) at 160 ° C. for 5 hours, using an injection molding machine Dynamelter M-100DM manufactured by Meiki Seisakusho, 50 g at a cylinder temperature of 295 ° C. Preform, and blow molding machine RHB manufactured by Cincinnati Milacron Co., Ltd.
-Using L, inner volume 1.5 liter, body thickness 0.3 mm
Bottle. The intrinsic viscosity after molding was 0.70. The bottle was crushed into flake-like particles (B ₁ ).

The temperature and the residence time during the injection molding were changed, and particles B ₂ and B ₃ were molded and pulverized in the same manner. Table 1 shows the properties of each polymer.

[0035]

[Table 1]

(Preparation of Particles C) Teijin polyester resin TR-8550T (particles A) was hydrothermally hydrolyzed in an autoclave under the conditions shown in Table 2 to prepare particles C ₁ , C ₂ and C ₃ . did. The polymer properties are shown in the right column of the table.

[0037]

[Table 2]

[0038]

Examples 1 to 4 and Comparative Examples 1 to 6 A bottle was formed by mixing the above-mentioned particles B and C with a predetermined ratio under the conditions of polyester resin TR-8550T (particle A) manufactured by Teijin. Table 3 shows the properties of the molded product.

[0039]

[Table 3]

If the degree of hydrolysis of the particles C is too high, the physical properties (intrinsic viscosity) of the bottle are greatly reduced and the crystallization is rapid (Tc
i), the transparency of the bottle deteriorated, and the height became shorter (Comparative Example 3).

Conversely, when the degree of hydrolysis of the particles C was small, the crystallization rate was low and the height was long (Comparative Example 4).

When the amount of the particles C ₁ was too small, the amount of the oligomer was increased, and the stain on the mold became severe (Comparative Example 5).

Conversely, if the amount of C ₁ was too large, the physical properties of the bottle were reduced (intrinsic viscosity).

Although the above has been specifically described with reference to bottle molding as an example, the present invention is not limited to bottle molding materials.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroki Nagano 77, Kitayoshida-cho, Matsuyama-shi, Ehime Prefecture Teijin Limited Matsuyama Office (56) References JP-A-57-31948 (JP, A) (58) Investigated Field (Int.Cl. ⁷ , DB name) C08J 3/00-3/28 C08L 1/00-101/16

Claims (1)

(57) [Claims] 1. A polyester comprising an aromatic dicarboxylic acid and an aliphatic glycol having an intrinsic viscosity of 0.6.
5~0.90dl / g and a particle element A, once melt-molding the particles A, it pulverized or pelletized particles B, and than its intrinsic viscosity particles A was hydrolyzed the particles A 0 It is a mixture of three kinds of particles C, which is reduced by 0.01 to 0.25 dl / g, and has a weight ratio of (B + C): A
= 8 to 20: 92 to 80 and a mixture of polyester particles, wherein the particles C account for 1% or more of the whole.