JPH10195204A - Polyester granular chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide polyester granular chips that resist fusion among granular chips or powdering during drying or solid-phase polymerization and show high polymerization rate in the solid-phase polymerization. SOLUTION: The shape of this granular chip has the following characteristics: (1) 0.4<=(S1/S2)<=0.95, (2) 0.3<=(H1/H2)<=1, and (3) 0.2<=(M)<=0.06 where S1 is the surface area in mm<2> at the cut part; S2 is the surface area in mm<2> of a granule formed by natural cooling but not cutting; H1 is the average length of the minor axis of a chip cut on both ends in mm; H2 is the average length of the major axis of a chip cut on both ends in mm; M is a weight or every granular chip in g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a granular chip made of polyester. More specifically, the present invention relates to a granular chip made of polyester, which is characterized in that it is difficult for fusion or powder of granular chips to occur during drying or solid phase polymerization, and that the rate of increase in the degree of polymerization is high during solid phase polymerization. ..

[0002]

2. Description of the Related Art Polyester has been widely used as a molded article such as a fiber, a film and a hollow container because of its excellent physical and chemical properties.

[0003] Such polyesters are generally molded by a melt molding method, and if moisture is present during melting, a significant reduction in the degree of polymerization is caused by hydrolysis. Therefore, a drying step is indispensable for molding.

When this drying is performed at a high temperature of 80 ° C. or more,
The granular chips are plasticized and deformed, or the granular chips fuse together.

[0005] This fusion is more likely to occur in a naturally cooled portion formed by natural cooling regardless of cutting than in a cut portion in which crystallization is progressing due to shearing force during cutting.

[0006] When the granular chips are fused together, dry chips are generated or biting into the melting device is deteriorated, making molding difficult.

For this reason, Japanese Unexamined Patent Publication (Kokai) No. 52-29856 discloses a method of forming an uneven portion on the surface of a granular chip.
In Japanese Patent Application Laid-Open No. 9, the concave portion is provided on the surface of the granular chips to reduce the contact area between the granular chips during drying.

[0008] In these methods, fusion of the granular chips during drying is reduced, but the degree of polymerization during solid-phase polymerization generally performed when a molded article requires ultra-high strength is required. The ascending speed is not so high or a slight effect of the slight increase in the specific surface area can be expected.

As a method of increasing the degree of polymerization increase during the solid-phase polymerization by changing the shape of the granular chips, it is known to increase the specific surface area of the granular chips or to reduce the size of the granular chips. Powder is likely to be generated during the polymerization, which adversely affects the molding.

When the surface state of the naturally cooled portion formed by natural cooling and the surface state of the cut portion are compared, the cut portion having not less than a small amount of unevenness due to cutting has a larger specific surface area.

It is apparent from the above that the deglycolization reaction and the esterification reaction in the solid-phase polymerization are more active at the cut portion.

Therefore, it has been intensively studied to obtain a granular chip in which fusion and powder of the granular chips hardly occur during drying and solid-phase polymerization, and a rapid increase in the degree of polymerization during solid-phase polymerization. As a result, the present invention has been reached.

[0013]

DISCLOSURE OF THE INVENTION The object of the present invention is to prevent fusion between granular chips or powder during drying and solid phase polymerization, and to increase the degree of polymerization during solid phase polymerization. It is to provide a fast polyester granular chip.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide a granular chip made of polyester having the following characteristics. (1) 0.4 ≦ (S1 / S2) ≦ 0.95 (2) 0.3 ≦ (H1 / H2) ≦ 1 (3) 0.02 ≦ (M) ≦ 0.06 where S1 is cut surface area parts (mm ^2), S2 is said surface area of the natural cooling part formed by natural cooling regardless of cut (mm ^2), H1 is the average length of the minor axis of the two cutting portions (mm), H2 is It means the average length (mm) of the major axis of both cut portions. M means the weight (g) per one granular chip.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a granular chip is obtained by extruding polyester in a molten state from a small hole as a columnar body.
It is manufactured by cutting from a direction transverse to the direction of extrusion while the solidification or surface has not yet completely solidified.

The columnar body referred to here is a columnar body whose surface may be partially oriented, but is substantially non-oriented, and the shape of the columnar body is such that a melt of polyester is formed in the shape of a cut portion. Although it can be easily changed into various shapes depending on the shape of the extrusion die, it generally has a circular or oval shape.

The present invention will be described with reference to the drawings. The shorter diameter (H1A) and the longer diameter (H2A) of the near-side cut portion cut in a lateral direction with respect to the extrusion direction in FIG. 1 with a caliper or the like, and the shorter diameter (H1B) and the longer diameter of the other cut portion in FIG. (H2B) and the length (L) in the extrusion direction are measured.

In the equation (1), the surface area (S1
A) and the surface area (S1B) of the other cut portion are calculated.

The sum of the surface area (S1A) of the front cut portion and the surface area (S1B) of the other cut portion is the surface area (S1) of the cut portion.

The average of the minor axis (H1A) of the front cut portion and the minor axis (H1B) of the other cut portion is the average minor axis length (H1) of both cut portions, and the major axis (H1A) of the near cut portion. The average of H2A) and the major axis (H2B) of the other cut portion is the average major axis length (H2) of both cut portions. Then, the perimeter (LA) of the front cut portion and the perimeter (LB) of the other cut portion in FIG. 2 which are cut in the lateral direction with respect to the extrusion direction in FIG. . The surface area (S2) of the natural cooling part formed by natural cooling without cutting is (3)
It is calculated by the formula. In the formula, π represents the pi.

[0021]

(Equation 1)

[0022]

(Equation 2)

[0023]

(Equation 3) As for the shape of the granular chips, the ratio of the surface area (S1) of the cut part to the surface area (S2) of the natural cooling part is 0.4 ≦ (S1 / S2).
≦ 0.95, preferably 0.5 ≦ (S1 / S2)
≦ 0.9, more preferably 0.6 ≦ (S1 / S2)
≦ 0.85. When the surface area ratio is (S1 / S2) <0.
In the case of No. 4, the rate of increase in the degree of polymerization during the solid-phase polymerization becomes slow, and in the case of drying and solid-phase polymerization, fusion of the granular chips and powder are easily generated, which is not preferable. The surface area ratio is (S
When (1 / S2)> 0.95, the rate of increase in the degree of polymerization during solid-phase polymerization is increased, but powder is easily generated during drying and solid-phase polymerization, which is not preferable.

The ratio of the minor axis average length (H1) to the major axis average length (H2) of both cut portions is 0.3 ≦ (H1 / H2) ≦ 1, preferably 0.35 ≦ (H1 / H2). ) ≦ 0.9, more preferably 0.4 ≦ (H1 / H2) ≦ 0.8
It is. The average length ratio between the minor axis and the major axis is (H1 / H2) <
When the ratio is 0.3, it is not preferable because fusion and powder of the granular chips are liable to occur during drying and solid phase polymerization. The weight (M) per granular chip is 0.02 ≦ (M) ≦ 0.06, preferably 0.025 ≦ (M) ≦ 0.05, more preferably 0.03 ≦ (M) ≦ 0.04. When the weight per particle is (M) <0.02, powder is liable to be generated during drying and solid phase polymerization, which is not preferable. Also (M)>
If it is 0.06, the rate of increase in the degree of polymerization during solid-state polymerization is undesirably reduced.

The polyester of the present invention is a polyester containing an aromatic dicarboxylic acid as an acid component. The aromatic dicarboxylic acid is mainly terephthalic acid or 2,6-naphthalene dicarboxylic acid, and a part thereof is a mutual or other aromatic dicarboxylic acid such as isophthalic acid or naphthalene dicarboxylic acid other than 2,6-. It can be substituted with one or more of acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid and the like.

Part of the aromatic dicarboxylic acid is one or more of an alicyclic dicarboxylic acid such as oxycarboxylic acid and cyclohexanedicarboxylic acid, and an aliphatic dicarboxylic acid such as succinic acid, adipic acid and sebacic acid. Can be replaced.

The glycol component of the polyester is mainly ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol or hexamethylene glycol.
Some of these are mutually or other glycols such as neopentylene glycol, diethylene glycol, 2,
It can be substituted with 2-bis (4-β-hydroxyethoxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) propane and the like.

The polyester is produced by synthesizing a low polymer by a reaction such as esterification or transesterification of the acid component and the glycol component, and then subjecting the low polymer to a polycondensation reaction under high temperature and reduced pressure. can do.

In the range where the polyester is substantially linear, trifunctional or higher polyfunctional compounds such as trimethylolpropane and trimellitic acid, or benzoic acid, diphenylsulfone-4-carboxylic acid, and methoxypolyethylene glycol can be used. Such a monofunctional compound may be reacted, or other additives such as various stabilizers, pigments, fillers and the like may be added.

In the present invention, the same effects as those of the present invention can be obtained by blending polyester or other components with a known method in a melter using a mixer, forming granulated chips, and drying and solid-phase polymerization. Obtainable.

[0031]

The present invention will be described in more detail with reference to the following examples. In the examples, the intrinsic viscosity [η] is a value when the polyester composition is dissolved in o-chlorophenol and measured at 25 ° C.

The "degree of fusion between the granular chips" in the embodiment is defined as follows. 30 g of granular chips are placed in a cylindrical glass container having an inner diameter of 5 cm, and an outer diameter of 4.7 g is placed thereon.
A cylindrical glass container corrected in cm and weight to 160 g is placed.

It was placed in a drier, heated at 170 ° C. for 1 hour, and then immediately placed on a granular chip with an outer diameter of 4.7.
The cylindrical glass container whose cm and weight have been corrected to 160 g is removed and left to cool for 30 minutes.

After cooling, vibration is applied with a rotary shaker at 160 rpm for 30 seconds.

The granular chips are classified into the following four stages according to the state of the granular chips when the granular chips are taken out.

A: There is hardly any fusion between the granular chips, and the individual chips are separated.

B: There is fusion between the granular chips, but when vibrated, they fall apart one by one.

C: There is fusion between the granular chips, but when mechanical stirring is applied, the individual chips are broken up one by one.

D: There is fusion between the granular chips, and even if mechanical stirring is applied, no separation occurs and a fusion portion remains.

If the state of the granular chips at the time of removal is A or B, there is no practical problem. The solid phase polymerization rate was as follows. A flask containing 100 g of granular chips and having a flowable irregularity portion of granular chips inside was heated in a silicon oil bath heated to 230 ° C. under a high vacuum of 0.5 Torr or less for 8 hours. The intrinsic viscosity [η] after the solid-phase polymerization was performed by rotating at 20 rpm was measured. Under these conditions, if the difference in intrinsic viscosity [η] before and after solid-state polymerization is 0.2 or more, it means that the rate of increase in the degree of polymerization during solid-state polymerization is high.

The amount of powder in the granular chips is 3,0 granular particles.
A diamond-shaped rotary dryer containing 00 kg was rotated at 10 rpm for 15 hours at room temperature and normal pressure, and then a sample was taken, and the granular chips and the weight of each granular chip were 80%. Separation and collection of less than% crushed material and fine powder,
Weight ratio of both after drying, (crushed material + fine powder) /
(Granular chips + crushed material + fine powder). If this powder amount is less than 500 ppm, there is no practical problem.

Example 1 1,160 kg of an esterification reaction product was previously placed in an esterification reaction vessel, and terephthalic acid 860 Kg was added thereto.
g and 370 Kg of ethylene glycol were charged over 3 hours.

During this time, a pressure of 1 × 10 ⁵ Pa was applied to the vessel, the temperature was kept at 250 ° C., and the generated water was discharged out of the system.

After the charging of the slurry mixture was completed, this state was maintained for 1 hour, and then 1,160 kg of the esterification reaction product was transferred to a polycondensation reaction vessel.

Then, 0.4 kg of antimony trioxide, 0.1 kg of manganese acetate, 0.05 kg of phosphoric acid were charged,
The polycondensation reaction was performed at 80 ° C. under a reduced pressure of 20 Pa or less for 3 hours.

After the completion of the polycondensation reaction, the polymer was extruded into a cylindrical shape through a small hole having a diameter of 9 mm at the lower portion of the polycondensation reaction vessel, and the polymer was extruded by 2.5 times
mm length and the average length of the minor axis of both cut parts is 2.5
5 mm, average length of major axis 4.45 mm, intrinsic viscosity [η]
A 0.65 polyester granular chip was obtained, and the degree of fusion between the granular chips, the rate of increase in the degree of polymerization during solid-phase polymerization, and the amount of generated powder were examined.

Examples 2 and 3, Comparative Examples 1 to 5 Polyester granular chips were obtained in the same manner as in Example 1 except that the cut length, the short diameter and the long diameter of the cut surface were changed as shown in Table 1. Regarding the granular chips, the degree of fusion between the granular chips, the rate of increase in the degree of polymerization during solid phase polymerization, and the amount of generated powder were examined.

As is clear from Table 1, in Examples 1 to 3 carried out within the scope of the claims, there were no problems with the fusion of the granular chips, the rate of increase in the degree of polymerization during solid phase polymerization, and the generation of powder.
Comparative Examples 1 to 5 performed outside the scope of the claims have the disadvantage that the degree of fusion between the granular chips is large, the rate of increase in the degree of polymerization during solid-state polymerization is slow, or the generation of powder is large, Had.

[0049]

[Table 1]

[0050]

When the polyester granular chips of the present invention are used for drying, the fusion of the granular chips is unlikely to occur and the temperature rising rate can be increased, so that the drying time can be shortened and solid phase polymerization can be performed. When used, the time required for drying can be shortened, and also the time for solid phase polymerization can be shortened.

As a result, the ability of drying and solid-phase polymerization can be greatly increased, and powder is not easily generated during drying and solid-phase polymerization, so that there is no adverse effect on molded articles.

[Brief description of the drawings]

FIG. 1 is a view of a granular chip according to the present invention as viewed from one cut portion direction.

FIG. 2 is a view of the granular chip according to the present invention as viewed from the other cut portion direction.

[Explanation of symbols]

S1A: Surface area (mm ² ) of the near-side cut portion cut from the lateral direction to the extrusion direction. S1B: Surface area (mm ² ) of the other cut portion cut in a direction transverse to the extrusion direction. S1: Surface area of cut portion (mm ² ). S2: Surface area (mm ² ) of the naturally cooled portion formed by natural cooling without cutting. H1A: Short side diameter (mm) of the front side cut portion cut from the lateral direction with respect to the extrusion direction. H1B: short diameter (mm) of the other cut portion cut from the transverse direction to the extrusion direction. H1: Average minor axis length (mm) of both cut portions. H2A: The long diameter (mm) of the near-side cut portion cut from the lateral direction with respect to the extrusion direction. H2B: the major axis (mm) of the other cut portion cut from the transverse direction to the extrusion direction. H2: Longest diameter average length (mm) of both cut portions. L: Length in the extrusion direction (mm) LA: Perimeter (mm) of the near-side cut portion cut from the side in the extrusion direction. LB: Perimeter (mm) of the other cut portion cut from the transverse direction to the extrusion direction.

Claims (1)

[Claims] 1. Granular chips made of polyester having the following characteristics: (1) 0.4 ≦ (S1 / S2) ≦ 0.95 (2) 0.3 ≦ (H1 / H2) ≦ 1 (3) 0.02 ≦ (M) ≦ 0.06 where S1 is cut surface area parts (mm ^2), S2 is said surface area of the natural cooling part formed by natural cooling regardless of cut (mm ^2), H1 is the average length of the minor axis of the two cutting portions (mm), H2 is It means the average length (mm) of the major axis of both cut portions. M means the weight (g) per one granular chip.