JPH1120004A - Manufacture of thermoplastic resin sheet and production equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently obtain a sheet at high speed without impairing quality by a method wherein the position of a blade-like electrostatic applying electrode to a cooling rotator is adjusted biaxially and, at the same time, the angle between the normal direction of the cooling rotator and the blade-like electrostatic applying electrode is adjusted. SOLUTION: A blade-like electrostatic applying electrode 4 is provided in the neighborhood of the landing point 8 of a thermoplastic resin sheet to a cooling rotator 2 so as to bring the thermoplastic resin sheet 3 into close contact with the cooling rotator 2. Both the end parts of the blade-like electrostatic applying electrode 4 are covered with insulating members 5, the end part of each of which is supported with a holding part 6. The holding part 6 is made slidable on a fixed stand 13 and horizontally adjusted with a bolt 10 under the condition that a stay 11 cats as a fulcrum and vertically adjusted with the hold 12. Further, with the rotating devices 14 at both the end parts of the electrostatic applying electrode 4, the angle between the normal direction of the cooling rotator 2 and the blade-like electrostatic applying electrode 4 is preperly adjusted. As a result, the applying electrode can be easily and accurately adjusted to an optimum position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a thermoplastic resin sheet which is extruded from a die into a sheet shape and closely adheres to a cooling rotator to be cooled and solidified.

[0002]

2. Description of the Related Art In a crystalline thermoplastic polymer such as polyethylene terephthalate, rapid cooling by bringing a thermoplastic resin extruded into a sheet shape from a die into close contact with a cooling rotating body can reduce the degree of crystallinity. It is important that if the crystallinity is excessively large, the sheet becomes brittle or the sheet manufacturing operation in the subsequent process becomes difficult, and productivity is significantly impaired. For this reason, a method of applying an electrostatic charge to the thermoplastic resin sheet is widely used as a means for bringing the thermoplastic resin sheet into close contact with the cooling rotator to rapidly cool the thermoplastic resin sheet.

[0003] In the production of an actual thermoplastic resin sheet, it is strongly required to rotate the cooling rotator at a high speed without impairing the sheet quality in order to improve the productivity of the sheet. In the method of applying an electrostatic charge to the resin sheet, it is important to efficiently apply more electrostatic charge to the thermoplastic resin sheet, and when the application of the electrostatic charge is insufficient, it is necessary to apply the electrostatic charge to the thermoplastic resin sheet. Adhesion with the cooling rotator becomes insufficient, causing a bubble-like defect in the sheet. On the other hand, if an attempt is made to apply an excessive amount of electrostatic charge, a pinhole-shaped defect occurs due to dielectric breakdown of the thermoplastic resin sheet, and as a result, the thermoplastic resin sheet becomes poor in quality, resulting in serious inconvenience in production. Invite.

[0004] Generally, as a method of applying an electrostatic charge,
An electrostatic applicator equipped with a wire-shaped electrode is known.
As described in JP-A-8116, in order to efficiently apply an electrostatic charge to the thermoplastic resin sheet from the wire-shaped electrostatic application electrode as described above, a DC connected to the wire-shaped electrostatic application electrode is used. It has been proposed that the position of a thermoplastic resin sheet be accurately adjusted in the vicinity of a landing point on a cooling rotary body while maintaining the voltage of a high-voltage power supply at an optimum level.

However, in order to achieve high-speed production by rotating the cooling rotator at a higher speed, for example, the above-mentioned wire-like electrostatic application electrode is contacted with, for example, JP-B-63-206.
No. 88, a blade-shaped electrostatic application electrode is used, compared to a wire-shaped electrostatic application electrode,
It has been proposed that even if the cooling rotator is further rotated at a higher speed, the thermoplastic resin sheet does not have the above-described bubble-like defects, so that a high-quality thermoplastic resin sheet can be efficiently produced. .

[0006]

However, according to experiments conducted by the present inventors, it has been found that the above-mentioned blade-shaped electrostatic application electrode has the following problems.

That is, the blade-shaped electrostatic application electrode is
When the electrostatic charge is applied to the thermoplastic resin sheet, the directivity of the application of the electrostatic charge is stronger than that of the wire-shaped electrostatic application electrode. Unless the positional accuracy of the placement of the electrostatic application electrode is more strictly controlled, the above-mentioned bubble-like defects and pinholes due to the insulation breakdown of the sheet are extremely likely to occur, and the thermoplastic resin sheet can be stabilized for a long time. It becomes difficult to produce continuously.

Accordingly, an object of the present invention is to provide a method and apparatus capable of producing a thermoplastic resin sheet at high speed and efficiently without deteriorating the quality of the sheet, focusing on such problems.

[0009]

In order to solve such a problem, the present invention comprises the following constitution. That is, claim 1
The method for producing a thermoplastic resin sheet according to the above includes a step of bringing the thermoplastic resin extruded into a sheet form from a die into a cooling rotating body by a blade-shaped electrostatic application electrode and cooling and solidifying the thermoplastic resin sheet. In the method, the position of the blade-shaped electrostatic applying electrode with respect to the cooling rotator is adjusted in at least two axial directions, and the angle between the normal direction of the cooling rotator and the blade-shaped electrostatic applying electrode is formed. And adjusting.

In the method for producing a thermoplastic resin sheet according to the second aspect, polyester is used for the thermoplastic resin. In the method for producing the thermoplastic resin sheet according to the third aspect, the thermoplastic resin sheet is further biaxially stretched. , Heat treated,
Biaxially oriented film.

According to a fourth aspect of the present invention, there is provided an apparatus for forming a thermoplastic resin sheet, the method comprising a step of bringing the thermoplastic resin extruded into a sheet form from a die into close contact with a cooling rotating body by a blade-shaped electrostatic application electrode to cool and solidify. In the thermoplastic resin sheet manufacturing apparatus, the distance in the normal direction of the cooling rotator between the cooling rotator-side end of the blade-shaped electrostatic application electrode and the thermoplastic resin sheet on the cooling rotator is set on the cooling rotator. Moving means capable of moving the blade-shaped electrostatic applying electrode in at least two axial directions with respect to the cooling rotator so that the electrostatic applying electrode can be adjusted at an arbitrary position of the cooling rotator; A rotating means capable of arbitrarily adjusting an angle between the electrode and the electrode.

According to a fifth aspect of the present invention, there is provided an apparatus for manufacturing a thermoplastic resin sheet, wherein a normal direction of a cooling rotator between an end of the blade-shaped electrostatic application electrode on the cooling rotator side and the thermoplastic resin sheet on the cooling rotator. Is X [mm], the peripheral speed of the cooling rotator is Y [m / min], and the voltage of the DC high-voltage power supply connected to the blade-shaped electrostatic application electrode is Z [kV]. aXY + b where 0.005 ≦ a ≦ 0.04, 0 ≦ b ≦ 7, the distance between the blade-shaped electrostatic applying electrode and the cooling rotator, and the connection to the blade-shaped electrostatic applying electrode. And the voltage of the DC high-voltage power supply to be controlled.

[0013] In the apparatus for manufacturing a thermoplastic resin sheet according to claim 6, the distance between the blade-like electrostatic application electrode and the thermoplastic resin on the cooling rotary member is in the range of 1 mm or more and less than 20 mm.

In the apparatus for manufacturing a thermoplastic resin sheet according to a seventh aspect, the voltage of the DC high-voltage power supply connected to the blade-like electrostatic application electrode is set in a range of 1 kV or more and less than 30 kV.

According to an eighth aspect of the present invention, in the above-mentioned apparatus, in the above-mentioned apparatus, a rotating means capable of arbitrarily adjusting an angle formed between a normal direction of the cooling rotator and the blade-shaped electrostatic application electrode. The angle between the normal direction of the cooling rotator and the blade-shaped electrostatic application electrode is 0 ° or more and 45 ° or more.
It is characterized by being adjusted within the range of less than.

In the apparatus for manufacturing a thermoplastic resin sheet according to the ninth aspect, the twist angle of the blade-like electrostatic application electrode is within ± 7.5 ° with respect to the die width direction.

[0017]

According to the method of manufacturing a thermoplastic resin sheet of the first aspect, the blade-shaped electrostatic applying electrode is moved so that the blade-shaped electrostatic applying electrode can be moved to an arbitrary position with respect to the cooling rotator. The direction of movement with respect to the cooling rotator is at least two axial directions, and the angle between the normal direction of the cooling rotator and the electrostatic applying electrode is arbitrarily adjusted. Since it is possible, it is possible to adjust the blade-shaped electrostatic applying electrode with high precision at an optimum position near the point of attachment of the thermoplastic resin sheet to the cooling rotator, and furthermore, in the normal direction of the cooling rotator. And the angle between the blade-shaped electrostatic application electrode and the blade-shaped electrostatic application electrode can be arbitrarily adjusted, so that the angle between the thermoplastic resin sheet and the blade-shaped electrostatic application electrode is also optimized, and the cooling rotator can be formed without causing defects in the sheet. Can rotate at high speed, The production of can be significantly improved.

According to the method for producing a thermoplastic resin sheet of the present invention, since the polyester is used as the thermoplastic resin, the sheet can be effectively adhered to the cooling rotary body by the blade-shaped electrostatic application electrode, so that the productivity is improved. It can be significantly improved. According to the method for producing a thermoplastic resin sheet of the third aspect, the thermoplastic resin sheet having excellent properties as described above is subjected to biaxial stretching and heat treatment to produce a biaxially oriented film. The film will also have excellent quality.

According to the thermoplastic resin sheet manufacturing apparatus of the present invention, the blade-like electrostatic application electrode has a cooling rotor side end (lower end) and the thermoplastic resin sheet on the cooling rotor in a normal direction. Moving means for arbitrarily moving the blade-shaped electrostatic application electrode in at least two axial directions with respect to the cooling rotator so that the distance can be adjusted at an arbitrary position on the cooling rotator; Since it includes a rotating device that can arbitrarily adjust the angle between the normal direction and the blade-shaped electrostatic application electrode, it can be accurately positioned at the optimum position near the landing point of the thermoplastic resin sheet on the cooling rotating body. It is possible to move the electrostatic applying electrode quickly and accurately, so that the angle between the thermoplastic resin sheet and the blade-like electrostatic applying electrode is also optimized, so that the electrostatic applying electrode can be moved quickly and accurately. Because it can rotate It can be produced without time-consuming to position adjustment of the applied electrode, the result, which can be improved productivity.

According to the thermoplastic resin sheet manufacturing apparatus of the present invention, the above relational expression: Z = aXY + b where 0.0
With 05 ≦ a ≦ 0.04 and 0 ≦ b ≦ 7, the distance between the blade-shaped electrostatic applying electrode and the cooling rotator, the peripheral speed of the cooling rotator, and the connection to the blade-shaped electrostatic applying electrode In order to control the voltage of the DC high-voltage power supply, in actual production, the set value of the distance between the electrostatic application electrode and the thermoplastic resin sheet on the surface of the cooling rotator, and the set value of the peripheral speed of the cooling rotator Since the set value of the voltage of the DC high-voltage power supply connected to the electrostatic application electrode can be set to an optimum value in relation to each other, it is possible to simultaneously improve the productivity of the thermoplastic resin sheet as well as the quality. it can.

According to the apparatus for manufacturing a thermoplastic resin sheet of the present invention, the distance between the blade-shaped electrostatic application electrode and the thermoplastic resin sheet on the cooling rotator in the normal direction is 1 m.
Because it is within the range of m to less than 20 mm, the electrostatic charge can be efficiently applied to the thermoplastic resin sheet from the blade-like electrostatic application device, and the voltage of the DC high-voltage power supply connected to the electrostatic application electrode is not unnecessarily increased. Therefore, during actual production,
In addition to ensuring the safety of workers working in the vicinity of the blade-shaped electrostatic application electrode and preventing discharge to a die other than the thermoplastic resin sheet, a thermoplastic resin sheet can be manufactured with high productivity in actual production. It will be.

According to the apparatus for manufacturing a thermoplastic resin sheet of the present invention, the voltage of the DC high-voltage power supply connected to the blade-like electrostatic application electrode is in the range of 1 kV to less than 30 kV. An appropriate amount of electrostatic charge applied to the thermoplastic resin sheet from the application electrode can be supplied, and bubble-like defects due to insufficient supply of electrostatic charge, and conversely damage to the surface of the thermoplastic resin sheet due to excessive supply of electrostatic charge, and furthermore, sheet Stable production becomes possible without causing pinhole-shaped defects due to dielectric breakdown.

According to the thermoplastic resin sheet manufacturing apparatus of the present invention, the cooling rotator can be arbitrarily adjusted by an angle between the normal direction of the cooling rotator and the blade-shaped electrostatic application electrode. The angle between the normal direction of the blade and the blade-shaped electrostatic applying electrode can be adjusted within a range of 0 ° or more and less than 45 °, so that the angle between the thermoplastic resin sheet and the blade-shaped electrostatic applying electrode is also optimal. As a result, the vibration of the blade-like electrostatic application electrode generated when applying an electrostatic charge from the blade-like electrostatic application electrode to the thermoplastic resin sheet can be reduced as much as possible, and as a result, the thickness unevenness of the sheet due to the vibration is greatly reduced. And the electrostatic charge can be efficiently supplied to the thermoplastic resin sheet, so that the productivity and quality of the thermoplastic resin sheet can be improved at the same time.

According to the apparatus for manufacturing a thermoplastic resin sheet of the ninth aspect, the twist angle of the blade-like electrostatic application electrode is within ± 7.5 ° with respect to the die width direction.
Since the electrostatic charge can be uniformly supplied to the thermoplastic resin sheet on the cooling rotator over the entire width, stable production can be performed without deteriorating the quality of the sheet.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. First, as the thermoplastic resin in the present invention, for example, polyethylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, poly-1,4-cyclohexane dimethylene terephthalate, polyethylene α, β-bis ( Polyesters such as 2-chlorophenoxy) ethane 4,4-dicarboxylate, polyolefins such as polyethylene, polypropylene, polybutene and poly-4-methylpentene-1, polyamides such as nylon 6, nylon 66 and nylon 12, polyimide , Polysulfones, polystyrenes, polyvinyls, polyester ethers, polycarbonates, polyester carbonates, polyether sulfones, polyetherimides, polyphenylene Sulfides and the like can be used. These resins may be used alone, or may be a copolymer or a mixture. Of course, other additives to these thermoplastics,
For example, an antistatic agent, a weather-resistant material, a lubricant made of inorganic particles or organic particles, wax, or the like, a pigment, or the like may be contained.

As the thermoplastic resin in the present invention, polyesters, especially polyethylene terephthalate, polyethylene isophthalate and polyethylene-2,6-naphthalate are effective among the above-mentioned ones. Here, “mainly” indicates that the polyester is contained in an amount of 70 mol% or more. The polyester may be a single polyester, a copolymer, or a simple mixture of other components at a ratio of less than 30 mol%.

FIG. 1 shows a general embodiment of an apparatus for producing a thermoplastic resin sheet according to the present invention. In FIG. 1, a thermoplastic resin supplied from an extruder (not shown) is widened in a width direction by a base 1 and then discharged in the form of a thermoplastic resin sheet 3. The thermoplastic resin sheet 3 is quenched after landing on the cooling rotator 2. In the present invention, the blade-shaped electrostatic application electrode 4 is located near the point 8 where the thermoplastic resin sheet 3 lands on the cooling rotator 2.
Is provided. The position of the landing point 8 varies depending on the relative position between the base 1 and the cooling rotator 2, and further varies depending on the thickness of the thermoplastic resin sheet 3 and the rotation speed of the cooling rotator 2. The blade-shaped electrostatic application electrode 4 is connected to a DC high-voltage power supply 7. By applying a DC high voltage to the flared electrostatic application electrode 4, electrostatic charges generated from the blade-shaped electrostatic application electrode 4 are discharged. The thermoplastic resin sheet 3 is applied to the thermoplastic resin sheet 3 and adheres to the cooling rotator 2 by the Coulomb force.

FIG. 2 shows an embodiment of the present invention. The lower end 41 of the blade-shaped electrostatic application electrode 4, that is, the end on the side of the cooling rotator 2 needs to be provided near the landing point 8,
When the lower end 41 is installed on the base 1 side from the landing point 8,
Because the Coulomb force of the electrostatic charge applied to the thermoplastic resin sheet before landing exerts a force to adhere to the cooling rotator 2, the landing point 8 fluctuates, and as a result, uneven thickness is induced on the sheet. Become. On the other hand, lower end 41 is landing point 8
In the case where it is installed on the side opposite to the base 1, the Coulomb force at the landing point 8 is reduced, so that air is caught from the landing point 8 and a bubble-like defect occurs.

If the distance X in the normal direction between the lower end 41 of the blade-shaped electrostatic application electrode 4 and the thermoplastic resin sheet 3 on the cooling rotator 2 is too large, the thermoplastic resin sheet in the vicinity of the landing point 8 is too large. The electrostatic charge cannot be applied sufficiently to
As described above, a bubble-like defect occurs. On the contrary, if the distance X is too small, a pinhole-like defect easily occurs due to dielectric breakdown of the thermoplastic resin sheet. Due to a slight change, the thermoplastic resin sheet 3 and the blade-shaped electrostatic application electrode 4 come into contact with each other, which causes inconvenience in production.

Further, assuming that the angle between the normal direction of the cooling rotator 2 and the blade-shaped electrostatic applying electrode 4 is θ, the electrostatic charge generated from the blade-shaped electrostatic applying electrode 4 is transferred to the landing point 8.
In order to efficiently apply the pressure to the thermoplastic resin sheet 3 in the vicinity of the above, it is necessary to appropriately adjust the angle θ.

As described above, the blade-shaped electrostatic application electrode 4
However, it is very important that the blade can be moved to an arbitrary position with respect to the cooling rotator 2. Therefore, the direction in which the blade-shaped electrostatic application electrode 4 can move with respect to the cooling rotator 2 must be at least two axial directions. Further, even if the position of the landing point 8 is changed due to the change of the production condition, the angle θ between the normal direction of the cooling rotator 2 and the blade-shaped electrostatic application electrode 4 is always appropriately adjusted. Being able to adjust is very desirable.

Another embodiment of the present invention is shown in FIG. At both ends of the blade-shaped electrostatic application electrode 4 located outside the thermoplastic resin sheet 3 in the width direction, the blade-shaped electrostatic application electrode 4 is generally provided with an insulating member 5 in order to avoid discharge to the cooling rotator 2. The end of the insulating member 5 is
Is held in. The support portion 6 is movable on the fixed base 13, and in the embodiment shown in FIG. 3, the bolt 10 is used as a moving means, and by rotating the bolt 10, the support portion 6 is horizontally moved around the stay 11 as a fulcrum. Direction can be adjusted. Further, the bolt 12 is used as another moving means, and by rotating the bolt 12, the support portion 6 can be adjusted in the vertical direction with respect to the fixed base 13. The bolt 10 and the bolt 12 constitute moving means in at least two axial directions in the present invention. Furthermore, rotating devices 14 are provided at both ends of the blade-shaped electrostatic application electrode 4 to appropriately adjust the angle θ between the normal direction of the cooling rotator 2 and the blade-shaped electrostatic application electrode 4. You can do it.

In the above embodiment, as shown in FIG. 4, the moving direction of the blade-shaped electrostatic application electrode 4 corresponds to the horizontal direction 21 by the moving means 10 and the moving direction of the moving means 12 Corresponds to the vertical direction 20,
More preferably, as shown in FIG. 5, the moving direction by the moving means 10 corresponds to the circumferential direction 22 of the cooling rotator 2, and the moving direction by the moving means 12 is the normal direction 2 of the cooling rotator 2.
3, the lower end 41 of the blade-shaped electrostatic applying electrode 4 and the thermoplastic resin sheet on the cooling rotator 2 when the blade-shaped electrostatic applying electrode 4 is moved corresponding to the landing point 8. Since the operation can always be performed with the distance X in the normal direction to 3 constant, desired adjustment can be performed accurately in a short time, and the operability during production is excellent.

Further, the distance between the lower end 41 of the blade-shaped electrostatic application electrode 4 and the thermoplastic resin sheet 3 on the cooling rotator 2 in the normal direction is X [mm], and the peripheral speed of the cooling rotator 2 is Y.
[M / min], assuming a voltage Z [kV] of the DC high-voltage power supply 7 connected to the blade-shaped electrostatic application electrode 4, the distance X, the peripheral velocity Y, and the voltage Z are in a close relationship. According to the experiments of the present inventors, Z = aXY + b, where 0.0
If controlled by the relational expressions of 05 ≦ a ≦ 0.04 and 0 ≦ b ≦ 7, high quality sheets can be efficiently produced. Here, the values of a and b are more preferably 0.01 ≦ a
≦ 0.03, 0 ≦ b ≦ 5. In actual production, the distance X in the normal direction between the lower end 41 of the blade-shaped electrostatic application electrode and the thermoplastic resin sheet 3 on the cooling rotator 2 is set.
Is always used at a constant value, the voltage Z of the DC high-voltage power supply 7 connected to the blade-shaped electrostatic applying electrode 4 and the peripheral speed Y of the cooling rotator 2 can be uniquely determined. Even when the peripheral speed of the cooling rotator 2 gradually increases, such as at the start of production, the voltage Z can always be set to an optimum value, so that it can be controlled very easily.

Here, the normal distance X between the lower end 41 of the blade-shaped electrostatic application electrode 4 and the thermoplastic resin sheet 3 on the cooling rotator 2 is 1 mm or more and less than 20 mm, and more preferably 2 mm or more and 12 mm. When the value is less than the above range, the electrostatic charge generated from the blade-shaped electrostatic application electrode 4 can be efficiently applied to the thermoplastic resin sheet 3, and as a result, the generated Coulomb force is large and the high-speed operation of the cooling rotator 2 becomes possible. .

According to experiments by the present inventors, the voltage Z of the DC high-voltage power supply 7 connected to the blade-shaped electrostatic application electrode 4 is 1 kV or more and less than 30 kV, more preferably 5 kV.
When the voltage was V or more and less than 15 kV, stable production was possible without causing defects in the sheet. At this time, when a resistor is separately added in the circuit, it goes without saying that the appropriate range of the voltage is increased by the relationship of voltage = current × resistance.

Next, as shown in FIG.
The angle θ formed between the normal direction of the cooling rotor 2 and the normal direction of the cooling rotor 2 is inclined toward the opposite base side with respect to the normal direction of the cooling rotator 2, and conversely inclined toward the base side. If the angle θ is defined as a minus direction, the rotation device 14 capable of arbitrarily adjusting the angle θ makes the angle θ −45 ° or more +4.
If the angle is adjusted within a range of less than 5 °, the electrostatic charge can be efficiently applied from the blade-shaped electrostatic applying electrode 4, so that the cooling rotator 2 can be rotated at a higher speed and the blade-shaped electrostatic applying electrode 4 itself can be rotated. Since the vibration generated at the time of application can be minimized, the thickness unevenness of the thermoplastic resin sheet 3 can be minimized.

Further, if the above-mentioned twist angle of the blade-shaped electrostatic application electrode 4 is Δθ [°], if Δθ is within ± 7.5 ° with respect to the die width direction, the thermoplastic resin sheet 3 Over the entire width, the electrostatic charge supplied from the blade-shaped electrostatic applying electrode 4 becomes uniform, and the vibration of the blade-shaped electrostatic applying electrode 4 can also reduce non-uniformity, thereby improving productivity and improving quality. Can be achieved at the same time.

In the present invention, if polyester is used as the thermoplastic resin, the blade-shaped electrostatic
Thereby, the cooling rotator 2 is effectively brought into close contact with the cooling rotator 2, so that productivity and quality are greatly improved, which is preferable.

It is also preferable to subject the thermoplastic resin sheet obtained in the present invention to biaxial stretching and heat treatment to form a biaxially oriented film. The method of biaxial stretching and heat treatment is not particularly limited, but as a typical method, a thermoplastic resin sheet is heated to a glass transition temperature or higher, and a low-speed, high-speed stretching roll is provided between stretching rolls, in one stage or in multiple stages. After stretching in the longitudinal direction, the longitudinally stretched film obtained by cooling is gripped by a clip, and the film is gripped by a tenter of a type in which the film is run. it can.

The material of the blade-shaped electrostatic applying electrode of the present invention includes a simple metal such as iron, nickel, molybdenum, tungsten, cobalt, chromium, and zirconium, and at least one of the above components. Alloys (eg, stainless steel, duralumin, etc.), or the above-mentioned metal simple substance or an alloy obtained by plating, etc., of which inexpensive stainless steel is practical and preferable. Also, as the shape, in its cross section,
The width W (FIG. 2) is 2 to 20 mm and the thickness t (FIG. 2) is 0.0
It is preferable that the ratio is 1 to 1 mm and the ratio of width / thickness is in the range of 50 to 1000, from the viewpoints of handling property, strength, and improvement of electrostatic application property due to concentration of electric charge. Further, it is preferable to apply tension to both ends so that the electrodes are not significantly deformed in order to prevent the electrodes from vibrating.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
Lower end 41 of blade-like electrostatic application electrode 4 and cooling rotator 2
Distance X [m in the normal direction to the upper thermoplastic resin sheet 3
m], the peripheral velocity Y [m / min] of the cooling rotator 2, the voltage Z [kV] of the DC high-voltage power supply 7 connected to the blade-shaped electrostatic application electrode 4, and the normal direction of the cooling rotator 2. And the twist angle Δθ [°] of the blade-shaped electrostatic applying electrode 4 and the apparatus for manufacturing a thermoplastic resin sheet according to the present invention. For Comparative Example, a polyester was used as a thermoplastic resin, and the occurrence of surface defects of the sheet was compared and tested. Table 1 shows the results.

[0043]

[Table 1]

As shown in Table 1, Examples 1 to 6 were used.
Sets the distance X between 1 mm and 20 mm, sets the voltage Z between 1 kV and less than 30 kV, sets the angle θ between −45 ° and less than + 45 °, and sets the twist angle Δθ to 2
Since the sheet surface was set within 0 °, the sheet surface was good without defects, but in Comparative Example 1, the distance X was set to 22 mm, so that the electrostatic charge from the blade-shaped electrostatic application electrode 4 was insufficiently applied. And a sheet-like defect occurred in the sheet.
In Comparative Example 2, although the distance X was 12 mm, the voltage Z was set to 33 kV, so that a pinhole-shaped defect occurred due to insulation breakdown of the sheet. Further, in Comparative Example 3, since the angle θ was set to −50 °, the blade-shaped electrostatic application electrode 4 vibrated, and as a result, the sheet thickness accuracy was deteriorated, and a bubble-like defect was also caused. Further, in Comparative Example 4, since the twist angle Δθ was set to 12 °, the close contact between the thermoplastic resin sheet 3 and the cooling rotator 2 became uneven in the width direction, and the high-speed rotation test of the cooling rotator 2 was interrupted. . At that time, vibration of the blade-shaped electrostatic application electrode 4 was also generated, and the thickness accuracy was also deteriorated.

In the first to fourth embodiments, as shown in FIG. 6, the distance X, the peripheral velocity Y, and the voltage Z are substantially equal to 0.
There is a relationship of 022XY + 4.5. If the distance X is fixed to 6 mm, Z = 0.13Y + 4.5, and the peripheral velocity Y and the voltage Z can be uniquely determined, so that the control can be easily performed.

[0046]

According to the first aspect of the present invention, when the electrostatic charge is applied to the thermoplastic resin sheet, the directivity of the application of the electrostatic charge is changed to the wire-like electrostatic application. Since it is stronger than the electrodes, it is necessary to more strictly control the installation position accuracy of the blade-like electrostatic application electrode with respect to the position where the thermoplastic resin sheet is grounded to the cooling rotating body. The direction of movement of the blade-shaped electrostatic application electrode with respect to the cooling rotator is set to at least two axial directions so that the electrode can be moved to an arbitrary position with respect to the cooling rotator. Since the angle formed between the electrode and the electrode can be arbitrarily adjusted, a unique effect is obtained in that the electrode can be easily and accurately adjusted to an optimum position.

According to the second aspect of the present invention, since the thermoplastic resin is polyester, the above-mentioned effect of the present invention can be efficiently exhibited.

According to the third aspect of the present invention, by forming a biaxially stretched film, a film having excellent quality can be obtained as a final product film, and the effect of the present invention can be more remarkably confirmed. Has the effect of

According to the fourth aspect of the present invention, since the moving means for arbitrarily moving in at least two axial directions with respect to the cooling rotator is provided, the blade-like electrostatic application electrode can be accurately positioned at a predetermined position. In addition, a rotating device that can freely adjust the angle θ between the normal direction of the cooling rotator and the blade-shaped electrostatic applying electrode is provided. The angle of the body normal to the normal direction can be adjusted appropriately, as a result, the optimal amount of charge can always be applied to the thermoplastic resin sheet, it is possible to produce high quality products at high speed It works.

According to the fifth aspect of the present invention, the distance in the normal direction between the lower end of the blade-shaped electrostatic application electrode and the thermoplastic resin sheet on the cooling rotator, the peripheral speed of the cooling rotator, Since the voltage can be controlled in relation to the voltage of the DC high-voltage power supply connected to the electrostatic applying electrode, the optimum conditions can be determined quickly, and the specific effect of minimizing the production loss can be achieved.

According to the sixth aspect of the present invention, the distance in the normal direction between the lower end of the blade-shaped electrostatic application electrode and the thermoplastic resin sheet on the cooling rotator is kept optimal, so that the electrostatic charge can be efficiently reduced. It can be applied to a thermoplastic resin sheet well, and has a unique effect that a high quality sheet can be stably produced.

According to the seventh aspect of the present invention, the voltage of the DC high-voltage power supply connected to the blade-shaped electrostatic applying electrode is kept optimal, so that the electrostatic charge generated from the blade-shaped electrostatic applying electrode is reduced to a desired amount. As a result, a unique effect that high-quality sheets can be produced at high speed can be obtained.

According to the eighth aspect of the present invention, the angle between the blade-shaped electrostatic application electrode and the normal direction of the cooling rotator is kept optimal, so that the electrostatic charge is efficiently applied to the thermoplastic resin sheet. In addition to this, vibration of the blade-like electrostatic application electrode generated at the time of application can be reduced as much as possible, and a unique effect that a high-quality sheet with less unevenness in thickness can be obtained.

According to the ninth aspect of the present invention, since the twist angle of the blade-shaped electrostatic application electrode with respect to the width direction of the base is small, the statically applied thermoplastic resin sheet is uniformly spread over the entire length of the blade-shaped electrostatic application electrode. Since a charge can be supplied and the thickness accuracy can be made uniform, a unique effect that desired production with desired quality and no trouble can be performed can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a general configuration of an apparatus for manufacturing a thermoplastic resin sheet to which the present invention can be applied.

FIG. 2 is a schematic configuration diagram of an apparatus for manufacturing a thermoplastic resin sheet according to an embodiment of the present invention.

FIG. 3 is an enlarged partial perspective view showing a configuration example near the end of an electrostatic application electrode of the apparatus of FIG. 1;

FIG. 4 is a schematic configuration diagram illustrating an example of a moving direction of a blade-shaped electrostatic application electrode in the apparatus of the present invention.

FIG. 5 is a schematic configuration diagram showing another example of a moving direction of a blade-like electrostatic application electrode in the apparatus of the present invention.

FIG. 6 is a relationship diagram between Z and Y, showing an example of control of a voltage of a DC high-voltage power supply connected to a blade-shaped electrostatic application electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cap 2 Cooling rotating body 3 Thermoplastic resin sheet 4 Blade-like electrostatic application electrode 5 Insulating member 6 Indicating part 7 DC high-voltage power supply 8 Landing point 10, 12 Moving means 14 Rotating means

Claims (9)

[Claims] 1. A method for producing a thermoplastic resin sheet, comprising the steps of: bringing a thermoplastic resin extruded into a sheet shape from a die into a cooling rotating body by means of a blade-shaped electrostatic application electrode; and cooling and solidifying the thermoplastic resin sheet. Adjusting the position of the electrostatic application electrode with respect to the cooling rotator in at least two axial directions, and adjusting the angle between the normal direction of the cooling rotator and the blade-shaped electrostatic application electrode. To manufacture a thermoplastic resin sheet. 2. The method for producing a thermoplastic resin sheet according to claim 1, wherein the thermoplastic resin is a polyester. 3. The method for producing a thermoplastic resin sheet according to claim 1, wherein the thermoplastic resin sheet is subjected to biaxial stretching and heat treatment to form a biaxially oriented film. 4. The apparatus for manufacturing a thermoplastic resin sheet, comprising a step of bringing a thermoplastic resin extruded into a sheet shape from a die into close contact with a cooling rotator by a blade-shaped electrostatic application electrode and cooling and solidifying the thermoplastic resin. The blade so that the distance between the cooling rotating body side end of the electrostatic application electrode and the thermoplastic resin sheet on the cooling rotating body in the normal direction of the cooling rotating body can be adjusted at an arbitrary position on the cooling rotating body. Moving means capable of moving the shaped electrostatic applying electrode in at least two axial directions with respect to the cooling rotator, and arbitrarily adjusting the angle between the normal direction of the cooling rotator and the blade-shaped electrostatic applying electrode An apparatus for manufacturing a thermoplastic resin sheet, comprising: a rotating unit. 5. A distance between a cooling rotor side end of the blade-shaped electrostatic application electrode and a thermoplastic resin sheet on the cooling rotor in a normal direction of the cooling rotor, X [mm]. When the peripheral speed is Y [m / min] and the voltage of the DC high-voltage power supply connected to the blade-shaped electrostatic applying electrode is Z [kV], Z = aXY + b where 0.005 ≦ a ≦ 0.04 The relationship between the blade-shaped electrostatic applying electrode and the cooling rotator and the voltage of the DC high-voltage power supply connected to the blade-shaped electrostatic applying electrode are controlled by the relational expression of 0 ≦ b ≦ 7. Characterize,
An apparatus for manufacturing a thermoplastic resin sheet according to claim 4. 6. The distance between the blade-shaped electrostatic application electrode and the thermoplastic resin on the cooling rotating body is 1 mm or more and 20 mm or more.
The apparatus for producing a thermoplastic resin sheet according to claim 4, wherein the number is smaller than the number. 7. The thermoplastic resin sheet according to claim 4, wherein a voltage Z of a DC high-voltage power supply connected to the blade-shaped electrostatic application electrode is 1 kV or more and less than 30 kV. Manufacturing equipment. 8. A rotating means capable of arbitrarily adjusting the angle between the normal direction of the cooling rotator and the blade-shaped electrostatic application electrode, and the blade-shaped electrostatic force and the normal direction of the cooling rotator. The apparatus for manufacturing a thermoplastic resin sheet according to any one of claims 4 to 7, wherein an angle between the electrode and the application electrode is adjusted within a range of 0 ° or more and less than 45 °. 9. The thermoplastic resin according to claim 4, wherein a twist angle of the blade-like electrostatic application electrode is within ± 7.5 ° with respect to a die width direction. Equipment for manufacturing resin sheets.