JP4222084B2 - Polybutylene terephthalate chip, manufacturing method thereof, and piping transportation method thereof - Google Patents

Description

【００３２】
【表２】

【００３３】
表１から明らかなように請求範囲内で実施した実施例１〜３は、移送配管でのチップの閉塞がなく、計量時間が短く安定しており、伸度、Ｉｚｏｄが高く安定している。
一方請求範囲外で実施した比較例１〜７は、移送配管での閉塞が発生する；計量時間が長くばらつきがある；伸度、Ｉｚｏｄがばらつきがある、などのいずれかの欠点を有していた。
【００３４】
【発明の効果】
本発明のポリブチレンテレフタレート粒状チップを用いた場合は、コンパウンド、射出成型時の移送配管でのチップ閉塞がない。スクリューへの食い込みが安定し、計量時間が短く安定している。射出成形品の物性が安定している。等の成形作業の安定性向上、成形品物性が安定する効果を持つ。
【図面の簡単な説明】
【図１】典型的な形状のチップの模式図である。
【図２】 配管閉塞試験に用いた内径１０ｍｍφの１１０度のベント部を２カ所有する配管の模式図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polybutylene terephthalate chip and a pipe transportation method thereof. More specifically, the bite of the chip into the screw during compounding or injection molding is stabilized, and the physical properties of the injection molded product are stabilized. The present invention relates to a granular chip of polybutylene terephthalate capable of preventing clogging in a transportation pipe and a method for transporting the pipe.
[0002]
[Prior art]
Polybutylene terephthalate is widely used as an engineering plastic for electrical and electronic parts and automobile connectors because of its excellent physical and chemical properties.
Polybutylene terephthalate to be used for these moldings is generally produced by cutting a melt-formed strand, and its size is handling workability, bite into a molding machine screw, meltability in a molding machine, etc. From the surface, the cross section is a columnar or elliptical column having a major axis of about 1 to 5 mm, a minor axis of about 1 to 5 mm, and a length of about 2 to 5 mm.
[0003]
The granular chip is manufactured by extruding polybutylene terephthalate as a columnar body from a small hole in a molten state, and cutting it from a direction transverse to the extrusion direction while solidification or the surface is not yet completely solidified. However, as the number of strands cut increases and the number of chips increases, there are cases in which resin powder generated during cutting is mixed in the chips or chips are obliquely cut. If a molded product is molded using a chip mixed with a large amount of this resin powder or a chip mixed with diagonally cut chips, burns or unmelted material may be mixed in the molded product, resulting in poor biting. In some cases, molding defects occurred in the molded product.
[0004]
In addition, when the strand is not sufficiently cooled, the strand on the line flowing at a predetermined speed cannot be cut at a predetermined length, and a long chip is manufactured or discharged from the forming die. In some cases, a plurality of adjacent strands are connected to each other, and a twin-type chip that is cut as it is is manufactured. Molding using a chip containing a large amount of adhesion-type chips such as long chips and twin chips will cause chip weighing failure, and it will be caught by the hopper when it is put into the molding machine, or in the extruder. In some cases, the flow of the resin deteriorates, and molding defects such as burns occur in the molded product. Further, they are not easily melted, and the mechanical properties of the molded product may be deteriorated.
[0005]
In order to solve such problems, a polyester chip having a specific chip shape and a small amount of fine powder or fusion-type chip has been proposed (for example, see Patent Document 1). I can't say that. For example, the chip may be pneumatically transported between the cutter to silo, the silo to the packaging equipment, and the drying equipment to the molding machine at the time of molding. When the mold chip is mixed, there is a problem that the chip may be blocked in the pipe (particularly the bent portion) and transport may not be possible.
[0006]
[Patent Document 1]
JP2000-289022
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a polybutylene terephthalate chip in which the compound of polybutylene terephthalate, the bite of the chip during injection molding into the screw is stable, and the physical properties of the injection molded product are stable.
Another object of the present invention is to provide a polybutylene terephthalate chip capable of preventing clogging in a transportation pipe and a method for transporting the pipe.
[0008]
[Means for Solving the Problems]
As a result of intensive investigations to achieve the above-mentioned goal, the present inventors have determined that the weight of a predetermined amount of polybutylene terephthalate chips used for molding, the number of fusion chips, the number of long chips, the number of thick chips. The present invention has been completed by obtaining knowledge that the number of obliquely cut chips affects biting into the screw, the physical properties of the injection-molded product, and the blockage in the transport piping.
[0009]
That subject matter of the present invention is a polybutylene terephthalate chips obtained by cutting a strand of polybutylene terephthalate was discharged from the forming die, (1) 1.5 ≦ (M ) ≦ 3.0 ( However, M is the weight (g) per 100 granular chips, (2) the ratio of fusion-type chips is 700 ppm or less in terms of the number of chips, and (3) the ratio of obliquely cut chips with a cutting surface angle of 60 degrees or less is the chip. (4) The ratio of chips having a thickness of 5 mm or more is 300 ppm or less, and (5) The ratio of chips having a length of 10 mm or more is 500 ppm or less. (6) chip rate passing through the 24 mesh 30ppm or less as a chip weight, consists in polybutylene terephthalate chips is.
[0010]
Another gist of the present invention resides in a chip pipe transportation method characterized in that the polybutylene terephthalate chip is pneumatically transported using a chip transportation pipe having a pipe diameter of 10 to 30 mm.
Moreover, the method further aspect of the present invention, the strands of polybutylene terephthalate was discharged from the forming die is cut, by selecting the resulting machine sieve chips by cutting, the production of the polybutylene terephthalate chips a is, cut after contacting the cooling water and 0.3 seconds the strands, this by a vibrating screen device Furuiana径is 5 to 10 mm, frequency 1800～3600Rpm, amplitude 0.75mm~ The present invention resides in a method for producing a polybutylene terephthalate chip, which is characterized by screening at 3 mm.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The polybutylene terephthalate chip of the present invention is a chip (granular material) made of polybutylene terephthalate obtained through a polycondensation reaction after an esterification reaction or a transesterification reaction according to a conventional method. The polybutylene terephthalate obtained by the polycondensation reaction is usually transferred from the bottom of the polycondensation reaction tank to a polymer extraction die and extracted in the form of a strand, while being cooled with water or after being cooled with water and then cut with a cutter to obtain chips. The
[0012]
The polybutylene terephthalate used in the present invention is a polymer having a structure in which a terephthalic acid unit and a 1,4-butanediol unit are ester-bonded, and 50 mol% or more of the dicarboxylic acid unit is composed of a terephthalic acid unit, This means that 50 mol% or more of the components are composed of 1,4-butanediol units. Among them, terephthalic acid units preferably occupy 70 mol% or more, more preferably 80 mol% or more, particularly 95 mol% or more of all dicarboxylic acid units, and 70 mol% or more, more preferably 80 mol of diol units. It is preferable that 1,4-butanediol units occupy% or more, particularly 95 mol% or more. When the amount of terephthalic acid units or 1,4-butanediol units is less than 50 mol%, the crystallization rate of polybutylene terephthalate is lowered, and the moldability is deteriorated.
[0013]
Carboxylic acid components used in addition to terephthalic acid can be substituted with one or more of alicyclic dicarboxylic acids such as oxycarboxylic acid and cyclohexanedicarboxylic acid, aliphatic dicarboxylic acids such as succinic acid, adipic acid, and sebacic acid. Can.
[0014]
The glycol component used in addition to 1,4-butanediol includes ethylene glycol, trimethylene glycol, pentamethylene glycol or hexamethylene glycol, a part of which is 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 or the like.
[0015]
Further, as long as the performance as polybutylene terephthalate is not impaired, a polyfunctional compound having three or more functions such as trimethylolpropane and trimellitic acid, or a simple compound such as benzoic acid, diphenylsulfone-4-carboxylic acid, and methoxypolyethylene glycol. A product obtained by reacting a functional compound may be used, or other additives such as various stabilizers, pigments, fillers, and the like may be added.
[0016]
Polybutylene terephthalate is produced by synthesizing a low polymer by a reaction such as esterification or transesterification of these acid component and glycol component, and then subjecting the low polymer to a polycondensation reaction under high temperature and reduced pressure. be able to.
[0017]
The polybutylene terephthalate chip of the present invention has the following characteristics. Each characteristic represents a characteristic as a set of a large number of chips. For example, each characteristic should be measured for each lot of the product, but in actuality, an arbitrary 100 g chip may be measured.
The shape of the chip is obtained by cutting a strand such as a columnar shape, an elliptical column shape, or a prismatic shape at a substantially right angle with respect to the extraction direction. FIG. 1 shows a chip having a typical shape, and the two cut surfaces of the chip have substantially the same size and the same shape. Accordingly, the size of the chip is defined by the thickness that is the diameter of the cut surface and the length that is the distance between the two cut surfaces. When the cut surface is not a circle, the thickness is the average value of the minor axis and the major axis.
[0018]
(1) 1.5 ≦ (M) ≦ 3.0 (where M is the weight (g) per 100 granular chips).
M is preferably 1.7 or more, and more preferably 1.8 or more. Moreover, 2.7 or less is preferable and 2.5 or less is still more preferable. When the value of M is out of the above range, a biting failure occurs, the measuring time of the chip becomes long, and the fluctuation width of the measuring time becomes large. In addition, the flow of resin in the extruder may deteriorate, and molding defects such as burns may occur in the molded product.
[0019]
(2) The ratio of fusion-type chips is 700 ppm or less as the number of chips.
The fused tip is a fusion of two or more tips obtained by cutting with a cutter, and the twin fused type is distinguished from a normal tip because the tip is constricted. .
The ratio of these fusion-type chips is preferably 500 ppm or less, and more preferably 400 ppm or less. When there are many of these fusion-type chips, they are caught by the hopper when they are put into the molding apparatus, or a bite defect occurs, and the measuring time of the chips becomes long and the fluctuation time of the measuring time becomes large. In addition, the flow of resin in the extruder may deteriorate, and molding defects such as burns may occur in the molded product. Further, such a chip is not easily melted, and the mechanical properties of the molded product are deteriorated.
[0020]
(3) The ratio of obliquely cut chips having a cut surface angle of 60 degrees or less is 2% or less as the number of chips.
The cut surface angle means an angle between the strand drawing direction and the cut surface, and is ideally 90 degrees. It is essential that the ratio of chips having an angle of 60 degrees or less (slant cut chips) is 2% or less in number, but it is preferably 1.5% or less, and more preferably 1% or less. preferable. In addition, since there are two cut surfaces, if one of the cut surface angles is 60 degrees or less, it is counted as a diagonally cut chip. If the number of obliquely cut chips is too large, a biting failure occurs, the chip measurement time becomes longer, and the fluctuation time of the measurement time increases. Further, it is not preferable because fine powder is easily generated by impact such as chip aerodynamic transportation.
[0021]
(4) The ratio of chips having a thickness of 5 mm or more is 300 ppm or less as the number of chips.
When the ratio of chips having a thickness of 5 mm or more is too large, the chips are caught by the hopper when they are put into the molding apparatus, or biting defects occur, the chip measurement time becomes long, and the fluctuation time of the measurement time increases. In addition, the flow of resin in the extruder may deteriorate, and molding defects such as burns may occur in the molded product. These are hardly melted, and the mechanical properties of the molded product are deteriorated.
A chip having a thickness of 5 mm or more is more preferably 100 ppm or less.
[0022]
(5) The ratio of chips having a length of 10 mm or more is 500 ppm or less as the number of chips.
As in the above (4), when the amount of chips having a length of 10 mm or more is large, the mechanical properties of the molded product are deteriorated.
A chip having a length of 10 mm or more is preferably 300 ppm or less, and more preferably 100 ppm or less.
(6) The amount of chips passing through 24 mesh is 30 ppm or less with respect to the chip weight.
This means that the amount of fine powder passing through 24 mesh is relatively small.
Such a fine powder chip is preferably 20 ppm or less, and more preferably 10 ppm or less. When the amount of fine powder is large, a biting failure occurs, and as a result, burns and unmelted materials are mixed into the molded product, or a molding failure occurs.
[0023]
As a method of manufacturing the chip having the shape described above, a method of cutting a strand and then passing it through a sieve device can be adopted. Preferably, the strand is cut after contacting the cooling water for 0.3 seconds or longer, Can be produced with high productivity by screening the screen with a vibration sieve having a sieve hole diameter of 5 to 10 mm at a frequency of 1800 to 3600 rpm and an amplitude of 0.75 mm to 3 mm.
The temperature of the cooling water used for cooling the strand is preferably 5 to 35 ° C, more preferably 15 to 25 ° C. The time for contacting the strand with the cooling water is preferably 0.3 to 2 seconds, and more preferably 0.5 to 1.5 seconds. If the contact time is too short, it becomes a cutting in a state where the strand is not completely cooled, causing a disadvantage that many miscut chips such as a fusion-type chip, a long chip, and a diagonally cut chip are generated. Although the generation of miscut chips is suppressed, a lot of fine powder is generated, and the cooling water tank facility is lengthened, resulting in an inconvenience that the facility cost is increased.
Next, the sieve hole diameter of the vibration sieve machine is preferably 5 to 10 mm, and more preferably 6 to 8 mm. The frequency is preferably 1800 to 3600 rpm, more preferably 1500 to 2000 rpm. Depending on the frequency, the amplitude is preferably 0.75 to 3.0 mm, and more preferably 1.0 to 2.5 mm.
By setting the sieve hole diameter, frequency, and amplitude within the above ranges, it is possible to properly treat miscut chips such as fusion-type chips, long chips, and diagonally cut chips generated by cutting, and fine powder with minimum sieve equipment. It can be efficiently applied to the chip.
[0024]
When the chip of the present invention is transported by piping, the diameter of the piping is usually 10 to 30 mm, preferably 15 to 25 mm. If the diameter of the pipe is too large, the amount of gas required for pneumatic transportation is large, and incidental equipment such as a pump needs to be enlarged, resulting in inconvenience in operation. Further, when the diameter of the pipe is small, the tip is likely to be blocked by the pipe.
[0025]
Further, when the tip of the present invention is transported by piping, if the tip has a length or thickness larger than the radius of the transport piping, the tip is blocked in the pipe (particularly the bent portion) and cannot be transported. This may cause trouble. Therefore, it is preferable that the ratio of chips whose length or thickness is equal to or greater than the diameter of the transport pipe is 1 ppm or less as the number of chips.
[0026]
【Example】
Hereinafter, the present invention will be described based on further detailed examples, but the present invention is not limited to these examples. In the following description, “part” or “%” is based on weight unless otherwise specified.
“Intrinsic viscosity”: the prepolymer obtained in Examples and Comparative Examples, and measurement of the polymer at 30 ° C. using a mixed solution of phenol / tetrachloroethane (weight ratio 1/1) as a solvent using an Ubbelohde viscometer. Determined by
“Piping blockage”: As shown in FIG. 1, using a pipe having two 110 ° vent portions with an inner diameter of 10 mmφ, the tip 1 Kg was allowed to flow down to confirm the presence or absence of blockage.
“Chip penetration”: In an injection molding machine (“FS-75” manufactured by Nissei Plastic Industry Co., Ltd.), at a cylinder temperature of 260 ° C., a screw rotation speed of 120 rpm, a primary pressure time of 1.0 second, and a mold temperature of 80 ° C. A predetermined molded piece weighing about 80 g was injection molded. At that time, the injection molding was performed 100 times, the measurement time of the material resin in each of them was measured, the average value and the standard deviation were calculated, and the results are shown in Table 1.
“Elongation at break”: measured by ASTM D-638.
“Izod impact strength”: Measured according to JIS-K-6719.
[0027]
[Example 1]
The following examples will be described.
2236 weight of slurry prepared by supplying both raw materials to the slurry preparation tank 1 from the raw material supply ports 1a and 1b at a ratio of 1.8 mol to 1 mol of terephthalic acid and mixing them with a stirrer Parts / Hr (TPA 6.81 mol part / Hr, BG 12.26 mol part / Hr) were continuously supplied to the esterification reaction tank 2 adjusted to a temperature of 230 ° C. and a pressure of 78.7 kPa (590 mmHg), and a catalyst was supplied. An oligomer having an esterification reaction rate of 97.5% is supplied by continuously supplying 1.06 parts by weight of tetra-n-butyl titanate / Hr from the port 2i and performing an esterification reaction with a residence time of 3 hours under stirring by a stirrer. Got.
[0028]
The oligomer obtained by the esterification reaction was continuously supplied to the first polycondensation reaction tank 3 adjusted to a temperature of 250 ° C. and a pressure of 2.66 kPa (20 mmHg), and the polycondensation was performed with a residence time of 2 hours under the stirring of the stirring device. The reaction was performed to obtain a prepolymer having an intrinsic viscosity of 0.250 dl / g. The prepolymer was continuously supplied to the second polycondensation reaction tank 4 adjusted to a temperature of 250 ° C. and a pressure of 0.133 kPa (1 mmHg), and the polycondensation reaction was further advanced with a residence time of 3 hours under stirring by a stirrer. A polymer having an intrinsic viscosity of 0.872 dl / g was obtained. The polymer was continuously supplied to the third polycondensation reaction tank 5 adjusted to a temperature of 250 ° C. and a pressure of 0.133 kPa (1 mmHg), and the polycondensation reaction was further advanced with a residence time of 2 hours under stirring by a stirring device. A polymer with an intrinsic viscosity of 1.20 dl / g was obtained.
[0029]
It is transferred to a polymer extraction die, the polymer is extruded from the die into a cylindrical shape, cooled for 0.9 seconds with cooling water at 20 ° C., then cut using a cutter, 100 pieces weighing 2.2 g, intrinsic viscosity [η] A 1.20 polybutylene terephthalate granular chip was obtained.
Thereafter, the obtained polybutylene terephthalate granular chip was subjected to a sorting process using a vibration sieve equipment having a frequency of 1800 rpm, an amplitude of 2.1 mm, and a sieve hole diameter of 6.5 mm.
[0030]
With respect to the granular chip, the chip biteability, Izod impact strength, and tensile elongation during molding were measured.
[Example 2]
Each physical property was measured and evaluated in the same manner as in Example 1 except that it was cooled with cooling water at 10 ° C. for 0.4 seconds and then cut with a cutter, and the results are shown in Table 1. .
[Example 3]
In the sieving process, each physical property was measured and evaluated in the same manner as in Example 1 except that the screening process was performed using a vibration sieving equipment having a frequency of 3600 rpm, an amplitude of 0.75 mm, and a sieve hole diameter of 5 mm. Is shown in Table 1.
[Comparative Examples 1-5]
In addition to the oblique chips, twins, triplet fused chips, chips with a length of 10 mmL or more, chips with a thickness of 5 mmφ or more, and 24 mesh pass fine powder separately added to the granular chips obtained in Example 1 as shown in Table 1 Were measured and evaluated in the same manner as in Example 1, and the results are shown in Table 1.
[Comparative Example 6]
Each physical property was measured and evaluated in the same manner as in Example 1 except that it was cooled with cooling water at 40 ° C. for 0.28 seconds and then cut with a cutter, and the results are shown in Table 1. .
[Comparative Example 7]
In the sieving process, each physical property was measured and evaluated in the same manner as in Example 1 except that the sieving process was performed using a vibrating sieving equipment having a frequency of 3600 rpm, an amplitude of 0.75 mm, and a sieve hole diameter of 10.5 mm. The results are shown in Table 1.
[0031]
[Table 1]

[0032]
[Table 2]

[0033]
As apparent from Table 1, Examples 1 to 3 carried out within the scope of claims have no chip clogging in the transfer pipe, are stable with a short measurement time, and have a high elongation and Izod.
On the other hand, Comparative Examples 1 to 7 carried out outside the scope of the claims have any drawbacks such as clogging in the transfer piping; long and variable measurement times; and unevenness in elongation and Izod. It was.
[0034]
【The invention's effect】
When the polybutylene terephthalate granular chip of the present invention is used, there is no chip blockage in the transfer pipe during compounding and injection molding. Biting into the screw is stable and the weighing time is short and stable. The physical properties of injection molded products are stable. This has the effect of improving the stability of molding operations such as, and stabilizing the physical properties of molded products.
[Brief description of the drawings]
FIG. 1 is a schematic view of a chip having a typical shape.
FIG. 2 is a schematic view of a pipe having two 110 degree vent parts with an inner diameter of 10 mm used for a pipe blockage test.

Claims (6)

A polybutylene terephthalate chips obtained by cutting the polybutylene terephthalate strands were discharged from the forming die, (1) 1.5 ≦ (M ) ≦ 3.0 ( where, M is granular chip 100 (Weight per grain (g)), (2) the ratio of fusion-type chips is 700 ppm or less as the number of chips, (3) the ratio of diagonally-cut chips whose cutting surface angle is 60 degrees or less is 2% or less as the number of chips ( 4) The ratio of chips with a thickness of 5 mm or more is 300 ppm or less as the number of chips, (5) The ratio of chips with a length of 10 mm or more is 500 ppm or less as the number of chips, (6) The ratio of chips passing through 24 mesh is 30ppm or less as a chip weight, polybutylene terephthalate chips is. ( 7 ) The polybutylene terephthalate chip according to claim 1 , wherein the average thickness is 3 mm or less. ( 8 ) The polybutylene terephthalate chip according to claim 1 or 2 , wherein the average length is 3 mm or less. A pipe transportation method for chips, wherein the polybutylene terephthalate chip according to any one of claims 1 to 3 is pneumatically transported using a chip transportation pipe having a pipe diameter of 10 to 30 mm. The chip transportation method according to claim 4 , wherein the ratio of the chips whose thickness and / or length is equal to or greater than the diameter of the transportation piping is 1 ppm or less as the number of chips. The method for producing a polybutylene terephthalate chip according to any one of claims 1 to 3, wherein the strand of polybutylene terephthalate discharged from the forming die is cut, and the chip obtained by cutting is selected with a sieving machine. a is, cut after contacting the cooling water and 0.3 seconds the strands, this by a vibrating screen device Furuiana径is 5 to 10 mm, frequency 1800～3600Rpm, amplitude 0.75mm~ A method for producing a polybutylene terephthalate chip, characterized by screening through 3 mm.

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