JPS59143608A - Manufacture of molding material made of polyester - Google Patents

Abstract

PURPOSE:To omit predrying process prior to manufacture of strengthened polyester resin, by kneading undried thermoplastic aromatic polyester, a reinforcing agent and the other additives under specific conditions by making use of a special extruding machine. CONSTITUTION:An extruder possesses two material supply ports and two vent holes, which are provided in order of the supply port 21, the vent hole 22, the supply port 23 and the vent hole 24. As for the extruder, thermoplastic aromatic polyester is supplied from the supply port 21 and a reinforcing agent and the other additives, for example, a filler, a core material, an accelerator of crystallization, a fire-resistant agent, a coloring agent and a plasticizer are supplied from the supply port 23. A staying time of polymer from the supply port 21 to the vent hole 22 is less than 120sec which is desirably less than 60sec, and the same from the port 23 to the vent hole 24 is less than 80sec which is desirably less than 50sec. The vent holes 22, 24 are connected with a vacuum generator, and at the time of kneading the respective vent holes are kept under decompressed states at less than 100 Torr, desirably less than 50 Torr.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing polyester molding materials. More specifically, the present invention relates to a method for producing a polyester molding material by kneading a thermoplastic aromatic polyester having a water content of 0.01% by weight or more, a reinforcing agent, and a filler in an extruder.

[Prior art]

Conventionally, thermoplastic aromatic polyester resins reinforced with glass fibers have many excellent properties and have been widely used in electrical parts, electronic parts, automobile parts, mechanical parts, and housing parts.

Thermoplastic aromatic polyester has low hydrolysis resistance during melting, and for example, hydrolysis occurs in the presence of moisture (e.g., 0.01 weight), and as a result, the polyester molecule ff1 (intrinsic viscosity ) is significantly reduced, making stable melt molding difficult, and the quality of the resulting molded product, such as deterioration in strength, appearance, etc., occurs. Therefore, thermoplastic aromatic polyester used for melt molding, melt cross-wiring, etc. has a moisture content of +1.007'r.
It is necessary to pre-dry it until it becomes less than i lji%.

This pre-drying must be carried out at a high temperature (usually 140'C or higher and 80C or lower) for a long time (usually 3 hours or more), which poses various restrictions in terms of equipment, workability, and cost. For example, drying polyester for an extruder with a high extrusion capacity requires special equipment, and is further subject to time constraints such as drying time before starting up extrusion operation and replacement time in the dryer when changing raw materials. Such capital investment, drying energy, replacement time, etc. are naturally reflected in the manufacturing cost, and these various costs account for a high proportion of the product cost.

[Purpose of the invention]

In order to reduce these various costs, the inventor of the present invention has conducted extensive studies on the possibility of omitting the drying process, and as a result, the inventors have discovered that using a specific extruder and under specific conditions, the undried PA-chocolated aromatic polyester and reinforced The present invention has been made based on the discovery that it is possible to obtain a molding material having the same properties as when using a pre-dried thermoplastic aromatic +1 polyester when kneaded with other additives.

Therefore, an object of the present invention is to provide a method for producing a polyester molding material using an undried thermoplastic aromatic polyester. A further object of the present invention is to provide a polyester molding material with reduced manufacturing costs.

[Structure of the invention]

The purpose of the present invention is to basically provide a method for producing a polyester molding material by kneading a thermoplastic aromatic polyester, a reinforcing agent, and other additives in an extruder, and the method includes the following (A) and (D) This can be achieved by a method characterized by:

(A) A supply port (1) for thermoplastic aromatic polyester in the extruder, a supply port (2) for reinforcing agents and other additives on the discharge side of the supply port (1), and a supply port (1) for the reinforcing agent and other additives. Supply [ko(
(B) providing a vent hole (1) between the supply port (2) and the discharge die;
Water content is 0.01 as thermoplastic aromatic polyester
(C) Supply port (1
) to the vent hole (1), and the residence time at the supply port (2) to the vent hole (14) to 80 seconds or less, and (D) the vent hole. (
1) and vent hole (2), 100 tolls each,
Keep under reduced pressure.

The extruder used in the present invention has two material supply locations and two vent holes.
), vent hole (1), supply port (2) l vent hole,
Any type of filter may be used as long as it is provided in the order of +21. For example, a negative screw type or a twin screw type may be used. It is best to use screws with a screw-like shape that can disperse crosstalk within an hour, and preferably screws with a re-type, kneading disc type, or bottle-shaped tile image type. '-Yo (・.

Extruder! tl: supply ITI (1) is used as a supply port for thermoplastic component 1 ester, (lt-supply port (2) number ma auxiliary thread 1" and other bulking agents (e.g. filling It is used as a guide for Aa o, Nuclear Qi 1j, Ikisho Ihii additive, Inflammatory agent 2 coloring agent, plasticizer, etc. Stable supply of (well, usually advantageous) to these supply ports and workability. For the sake of improvement, a series of HOSO/<-KA threads are used.

Further, the vent holes +1+ and +2+ are connected to a vacuum generator, and each vent hole is maintained under a reduced pressure of 100 Torr or less, preferably 50 Torr or less, and 71.degree. or less during crosstalk. The vent hole (1) has the function of venting moisture and other volatile substances contained in the thermoplastic aromatic + 1 reester, and the vent hole (2) acts to vent moisture and other volatile substances contained in the thermoplastic aromatic + It has the function of venting volatile substances such as moisture.The vacuum generator is connected to the vent hole, and its capacity can be selected depending on the degree of depressurization of the vent hole, and its model etc. can be selected arbitrarily. It is.

In kneading the thermoplastic aromatic polyester and other additives before reinforcement, the supply port (1) and the vent hole (
The polymer residence time at 11'j (well, it should be a time in which at least a portion of the thermoplastic aromatic polyester is melted and a vacuum seal can be formed, and hydrolysis does not substantially occur. Which time 1' !, 120 seconds or less, preferably 60 seconds or less, and preferably 10 seconds or more.Furthermore, the residence time from the supply port (2) to the vent hole (2) is such that the molten thermoplastic aromatic polyester This is the time when the reinforcing agent and other additives are added and kneading begins, the additives need to be dispersed appropriately, and the time should be such that hydrolysis of the polyester does not substantially occur.

This time is less than 80 seconds, preferably less than 50 seconds.

Moreover, it is preferable that it is 15 seconds or more.

The reason why reinforcing agents and other additives are supplied from the supply port (2) instead of from the supply port (1) is that if they were supplied from the supply port (1), the thermoplastic aromatic polyester would be easily decomposed by moisture. , fj of the polymer molecular needle (intrinsic viscosity) (because it is impossible for H lower to occur).

Another important reason is that reinforcing agents such as glass fibers are subjected to large shearing forces at the start of melting of the plastic all-aromatic polyester, causing the fibers to fracture. The reason is that the crow fiber length of the toughening agent increases, reducing its effectiveness.

The thermoplastic aromatic polyester used in the present invention is
It is a saturated linear aromatic polyester whose main acid component is an aromatic dicarboxylic acid, such as polyalkylene terephthanate such as polyethinone terephthanate and polytetramethylene terephthalate: a terephthalic acid component, an isophthalic acid component, and a hissyl acid component. Examples include polyarylate consisting of a phenol component, copolymers or mixtures containing these aromatic polyesters as main components, and the like.

Thermoplastic aromatic polyester is usually used as powder or granules (e.g. pellets, chips), but these powders absorb moisture during the manufacturing process and have a moisture content of 0.01% or more. Also, when left in the atmosphere, it absorbs moisture and has the above-mentioned moisture content. In the present invention, a thermoplastic aromatic polyester having a moisture content of 0.01% or less is used.The moisture content is preferably 2% by weight or less.

Examples of reinforcing agents used in the present invention include plate-like reinforcing agents such as glass reinforcing agents, horn glass flakes, and mica used as reinforcing agents for thermoplastic aromatic polyesters. Further, other additives include, for example, fillers, nucleating agents, crystallization promoters, mold release agents, lubricants, flame release agents, colorants, and plasticizers.

Anti-arc agents, stabilizers, ultraviolet absorbers, and other agents commonly used in reinforced polyester resins can be used.

These may be inorganic or 48-organic. Furthermore, these may be in powder form or in liquid form. The water content of the reinforcing agent and other additives is not particularly limited, and may be at most a few.It goes without saying that it is better to keep the water content as low as possible.

〔Effect of the invention〕

According to the present invention, it is possible to omit the pre-drying step before manufacturing the reinforced polyester resin, which was conventionally required by Fujisha, and the effect of reducing various costs including equipment and processes is significant.

If the polyester is sufficiently dried, for example, the moisture content is 0.00,
When the method of the present invention is applied to a thermoplastic aromatic polyester having a pA of 7% or less, it is less effective in suppressing the decrease in the intrinsic viscosity of the thermoplastic aromatic polyester than when the vent hole is not depressurized. However, the effect of reducing energy costs cannot be obtained. Therefore, the present invention can exhibit a remarkable effect on thermoplastic aromatic polyesters, which conventionally require sufficient drying.

〔Example〕

The present invention will be further explained below with reference to Examples.

Note that the intrinsic viscosity in the examples was measured at 25° C. using orthochlorophenol as a solvent. Further, in the comparative example, pre-drying of the polyester chips was carried out at 170° C. for 3 hours.

Comparative Example 1 Intrinsic viscosity 0.72. Preliminary drying of polyethylene telecrate chips with a moisture content of 0.15% by weight results in a moisture content of 0.00.
Dry chips of 4x'jk% were obtained. Using this dry chip, the short part of the dry chip 1001, tl, and 4oB
Using a certain amount of chopped strand glass (average fiber length: 3 degrees) and two folds of talc, the dimensions shown in Figure-IK,
The screw diameter of the shape is 65, the degree of vacuum in the vent hole 13 is 50 torr, and the cylinder temperature is 28 in a single screw vent type extruder.
The mixture was kneaded and extruded at 0°C to obtain pellets for injection molding.

Using this injection molding pellet, a test piece for strength measurement was molded using an injection molding machine.

The intrinsic viscosity of the injection molding pellet and the strength of the test piece were measured. The results are shown in Table 1.

Examples 1 to 4 and Comparative Examples 2 to 6 Intrinsic viscosity o72. Using polyethylene terephthalate chips with a water content of 0.25 and 40 parts by weight of chopped strand glass (average fiber length: 3i *) and 2 parts of talc per 100 parts of the chips, -2
Using a vented twin-screw extruder with a screw diameter of 65 tnvLs and having the shape shown in Figure 1, the degree of vacuum in the vent hole 22.24 was maintained at the Torr level shown in Table 1, and the mixture was kneaded, extruded, and injected at a cylinder temperature of 280°C. A pellet for molding was obtained. During this kneading and extrusion, bare 1
・The residence time (crosstalk time) up to hole 22 is 60 seconds,
The residence time (crosstalk time) from the supply port 23 of the glass and talc to the bedding 4 was 50 seconds.

Using this injection molding pellet, a test piece for strength measurement was molded using an injection molding machine.

On the other hand, for comparison, the degree of pressure reduction in the vent holes 22 and 24 was
The same procedure as in Examples 1 to 4 was carried out except for changing to the taller shown in the table (Comparative Examples 2 and 3).

Furthermore, as a raw material chip, the above-mentioned intrinsic viscosity is 0.72. Pre-dried polyethylene terephthalate chips with a water content of 0.25 wt-1t% (moisture content 0.004 wt%)
The same procedure as in Examples 1 to 4 or Comparative Examples 2 and 3 was performed except that .

The strength of these injection molding pellets and test pieces was measured. The results are shown in Table 1.

Table 1 Roofing A8TM D-256 Izonoto/;/Chi Non-impact strength As is clear from Table 1, the intrinsic viscosity and impact strength of the example were comparable to those of the conventional method in comparative example 1. It is being

Example 5.6 and Comparative Examples 7 to 9 Intrinsic viscosity 0.85. A polytetramethylene terephthalate chip with a water content of 0.20% by weight, and the chip Ioon
i part 40 parts chopped strand glass (average fiber length H3) + 1 slit part σ-) flame retardant (polycarbonate oligomer of tetrapropyl bisphenol A) and 0.4 parts by weight of mold release agent ( Low molecular weight polyethinone) was used in a twin-screw extruder with a bend (not shown in Figure 2), and the degree of vacuum in the vent hole 22. The mixture was kneaded and extruded with changes as shown in the table to obtain pellets for injection molding.

Using this injection molding pellet, a test piece for strength measurement was molded using an injection molding machine.

On the other hand, for comparison, the same procedure as in the above example was carried out except that the residence time was changed as shown in Table 2.

In addition, as a raw material chip, the upper limit viscosity is 0.85. Moisture content 0
．． The procedure was carried out in the same manner as in Example 207 (IQ'%) except that pre-dried polytetramethylene terephthalate chips were used.

The limiting viscosity of these injection molding chips and the strength of the test pieces were measured. The results are shown in Table 2.

Table 2 ■ Guizonotonosochi Mukan Strength ASTM D-256 From Table 2, when using non-dried polytetramethylene terephthalate, the kneading time +so/1. o.

In seconds, the decrease in intrinsic viscosity is +20/80.
In a short time of seconds, it becomes almost like a dry product (and even more than 60
It can be seen that at /40 seconds, the same result as in the case of dry chips can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a simplified top view of a vented single-screw extruder, and FIG. 2 is a simplified top view of a vented twin-screw extruder. 11: Supply port for raw material chips, 12: Supply port for additives. 13: Vent hole, 14: Dice. 15: Suffle, 2]: Supply port for raw material chips. 22: Vent hole, 23: Additive supply port. 24: Vent hole, 25: Dice.

Claims (1)

[Claims] When producing a molding material by kneading thermoplastic aromatic polyester, a reinforcing agent, and other additives in a 4-P extruder, an aromatic polyester supply port (1) is connected to the extruder, and the supply port (1) is A reinforcing agent and other additive supply port (2
), and a vent hole f between the supply port (1) and the supply port (2).
i+ is further provided with a vent hole (2) between the supply port (2) and the discharge die, and is made of thermoplastic aromatic polyester with a water content of 0. Use OI weight fi% or more (・, supply port fi
The residence time from + to the vent hole (11) is 120 seconds or less, and the residence time from the supply port (2) to the vent hole (2) is 80 seconds or less;
2) is maintained under a reduced pressure of 100 torr or less.