KR102037345B1 - T-die for extruder with improved phenomenon of drool - Google Patents

Abstract

The present invention relates to a T-die for an extruder for discharging a resin melt, which comprises: a T-die body forming an upper part of a T-die; and a T-die cover constituting a lower part of the T-die, being airtightly coupled to the T-die body, and detachable from the T-die body, wherein the T-die body and the T-die cover are in fluid communication, and a peelable heat resistant tape is applied to a bottom surface of the T-die cover.

Description

T-die for extruder with improved phenomenon of drool}

The present invention relates to a T-die for an extruder with an improved drool phenomenon.

As a method of manufacturing a sheet from a synthetic resin, an extrusion molding method is known together with a calender method, a solution casting method, and the like. The extrusion method is a method of forming by heating and fluidizing a resin in a heating cylinder using an extruder to continuously push the resin through a die. The resin in the form of a sheet formed by being discharged from the die may be subjected to a process of drying, stretching, or the like, whereby a finally usable sheet is obtained.

One of the extruders used in such an extrusion method is an extruder equipped with a T-die, and an exemplary structure thereof is shown in FIG. 1.

Referring to FIG. 1, the extruder 1 includes a barrel 2 and a screw 3 that are kneaded while being heated and melted and fed toward the nozzle 2a while heating and melting raw materials such as pellets composed of a polymer resin such as a thermoplastic resin. And the hopper 4 for supplying a raw material in the barrel 2 is provided. In addition, the barrel 2 can be equipped with the heater 5 in the outer periphery, and can heat inside. The discharge passage 10 for discharging the polymer resin may be fixed to the tip of the discharge port 2a provided in the extrusion direction of the polymer resin of the barrel 2. The discharge passage 10 may be supplied after being heated by a high pressure gas supplied from a gas supply unit 6 such as a gas compressor, which is connected to the gas heating unit 7 by a pipe or the like, and is connected first. The gas heating unit 7 may be provided with a heating unit such as a heater, for example, around the gas feed pipe.

2 schematically illustrates one aspect of a conventional T-die 100 for sheet manufacture. As shown in FIG. 2, the T-die 100 for manufacturing a sheet continuously extrudes a resin melt from the discharge flow path 300. However, when the material for preparing the sheet contains a crosslinking additive, in particular, an alkoxy vinylsilane-based compound together with a polymer resin, the vinylsilane-based vapor reacts with moisture in the outside atmosphere in a high temperature environment, Side reaction occurs that solidifies on the lip. Such side reactions include alkoxy vinylsilane-based compounds such as VTMS (vinyltrimethoxysilane) and VTES (vinyltriethoxysilane) in the crosslinking additives added to the resin, having a boiling point lower than the extrusion temperature, for example, 120 to 180 ° C. It occurs because it evaporates immediately after being discharged from the lip portion of the die 100 during the reaction extrusion process. As the extrusion progresses, such side reactions continue, and the drooling phenomenon increases in the lip portion of the die 100, and the grown drules are piled up and become larger, and the die lip portion reaches a point when the weight of the drool itself cannot be overcome. Desorbs from and moves down, falling into the resin extrudate. Drules dropped on the resin extrudate may be incorporated into the polymer resin, and a situation may arise in which drool is mixed on the surface of the resin extrudate. The drool thus formed is referred to herein as an 'external drool'.

On the other hand, the T-die has a structure in which the discharge flow path is coupled to the T-die, and since the discharge flow path is generally formed to have a diameter smaller than that of the T-die, the T-die is connected to the T-die near the T-die and the discharge flow path. The bent portion is formed. The inside of the T-die where the bent portion is formed is a phenomenon that the resin melt does not move smoothly and stagnates, and the stagnant resin melt grows to a certain size to form foreign matter. This foreign material grows gradually, and at some point, the foreign material is pushed out to the discharge port together with the normal resin melt, leaving a scratch (shark skin) on the extrudate. In this specification, the drules formed and pushed out inside the extruder are referred to as 'internal drools'.

Since the outer drool and the inner drool are different in appearance (color, shape) and physical properties from the polymer resin normally extruded, when the drool is mixed in the resin extrudate, the appearance and physical properties of the article molded from the resin extrudate are inhibited. It becomes the cause.

The present invention has been made to solve the above-mentioned problems of the prior art.

To this end, in the present invention, in the extruder T-die for manufacturing the separator sheet, it is possible to prevent the phenomenon that the physical properties and the appearance of the separator sheet are reduced by the drules formed inside and outside the extruder T-die. It is to provide a T-die for an extruder that can.

In addition, the present invention is to provide an extruder T-die designed to reduce the downtime of the extruder for drool removal.

In order to solve the above technical problem, the present invention provides a T-die for an extruder for discharging a resin melt, the T-die body constituting the upper portion of the T-die (T-die body); And a T-die cover constituting a lower portion of the T-die and being airtightly coupled to the T-die body and detachable from the T-die body, wherein the T-die body and the T- The die cover is in fluid communication and a T-die for an extruder is provided on the bottom surface of the T-die cover, to which a peelable heat resistant tape is applied.

According to a second aspect of the present invention, there is provided a T-die for an extruder, in which the fixing member is provided and coupled to one or both of the T-die body and the T-die cover in the first aspect.

According to a third aspect of the present invention, in the second aspect, a groove is formed at the engaging position of the T-die body, and a protrusion capable of engaging the groove is formed at the engaging position of the T-die cover. T-die for phosphorus extruder is provided.

According to a fourth aspect of the present invention, there is provided a T-die for an extruder, wherein in any of the first to third aspects the T-die cover is formed from a heat resistant material.

According to a fifth aspect of the invention, in any one of the first to fourth aspects the T-die cover is formed from a release treated polytetrafluoroethylene or a release treated metal or tungsten treated tin T-die for phosphorus extruder is provided.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the peelable heat resistant tape comprises a tape substrate of polyimide or polyamideimide material; And an adhesive layer formed on one surface of the tape base material.

According to a seventh aspect of the present invention, there is provided a T-die for an extruder, wherein in any of the first to fifth aspects the peelable heat resistant tape is a tape made of polyimide or polyamideimide. .

According to an eighth aspect of the invention, in any of the first to seventh aspects, the peel-off heat resistant tape is attached to a portion of the bottom surface of the T-die cover, wherein the T-die for the extruder Is provided.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the peelable heat resistant tape is attached with the exception of the discharge flow path portion of the lower surface of the T-die cover. T-die is provided.

According to the 10th aspect of this invention, the extruder provided with the T-die for extruders as described in any one of said 1st-9th aspect is provided.

When the separator sheet is manufactured using the extruder T-die according to the present invention, deterioration of the separator sheet physical properties and appearance due to the drules formed inside and outside the extruder T-die may be prevented to the maximum.

More specifically, with the simplified operation of applying the detachable cover and the peelable heat resistant tape according to the present invention to the T-die for the extruder and replacing the detachable cover and the peelable heat resistant tape in case of contamination by drool / foreign material The drool / foreign material can be easily removed, and the degradation of the sheet properties and the appearance of the separator sheet by the drool formed inside and outside the T-die for the extruder can be prevented to the maximum. In this case, the term 'drule' is understood to include both external and internal rules.

In addition, the time taken to clean and clean the extruder T-die for drool removal can be greatly reduced, and as a result, the time for stopping the extruder operation for the cleaning and cleaning can be greatly reduced. In addition, damage to the extruder components caused by cleaning and cleaning the extruder T-die is avoided.

1 is a perspective view schematically showing the side of a typical extruder used for extruding molten polymer resin.
2 is a view schematically showing a shape in which a drool is formed on a lower surface of a T-die in a conventional T-die for an extruder.
3 is a view schematically showing a shape in which a drool is formed on a lower surface of the T-die in the T-die for an extruder according to an embodiment of the present invention.
4A-4C are side views schematically showing a T-die body for an extruder according to one aspect of the present invention.
5 is a perspective view schematically showing a detachable T-die cover constituting the T-die for an extruder according to one aspect of the present invention.
6 is a perspective view schematically showing an embodiment in which a detachable T-die cover is coupled to a T-die body for an extruder according to an aspect of the present invention.
7 is a perspective view schematically showing an embodiment in which a detachable T-die cover is coupled to a T-die body for an extruder according to an aspect of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and are commonly used in the art to which the present invention pertains. It is provided to fully inform the scope of the invention to those skilled in the art, the invention being defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, the present invention will be described in more detail.

According to one embodiment of the present invention, an extruder T-die for discharging a resin melt, wherein the extruder T-die comprises: a T-die body constituting an upper portion of the T-die; And a T-die cover constituting a lower portion of the T-die and being tightly coupled to the T-die body and detachable from the T-die body, wherein the T-die body and the T-die The cover is in fluid communication and a T-die for an extruder is provided on the bottom surface of the T-die cover, to which a peelable heat resistant tape is applied.

Referring to FIG. 3, the T-die cover 110 is detachably coupled to the lower portion of the T-die body 100 to form an extruder T-die, and the die cover 110. Peel-off heat-resistant tape 120 is attached to the bottom surface. In one embodiment of the present invention, the T-die body 100 is provided with a groove portion bent inward, the projection of the die cover 110 is engaged with the groove portion in the lower portion of the T-die body 100 The T-die cover 110 may be engaged. In one embodiment of the present invention, the die cover 100 may have a discharge passage 300. The peelable heat resistant tape 120 has an external drool 200 formed during the manufacture of the crosslinked polyolefin separator or the like.

Referring to FIGS. 4A-4C, the T-die body is a component constituting the top of the T-die for the extruder, and may be in fluid communication with the T-die cover and with the T-die cover. If it can be combined is not particularly limited in terms of its shape. As a component for allowing the T-die body to be in fluid communication with the T-die cover, one or a plurality of openings may be exemplified, but a structure in which the entire lower surface is opened may be exemplified. no. Non-limiting examples of the shape of the T-die body may be a polygonal shape or a shape close to a truncated cone having a shape bent at a certain point in side view as shown in FIGS. 4A to 4C. According to the present invention, the bending shape and the number of bending are not particularly limited, but as shown in FIG. 4A, the diameter of the T-die body, for example, the inner diameter of the T-die body is reduced by the first bending, and then the second bending is performed. The diameter may increase again, and in the T-die having such a shape, a phenomenon in which the resin melt is formed as foreign matter in the T-die may be significantly reduced.

Referring to FIG. 5, the T-die cover 500 may include a space 510 and a discharge passage 520 that are combined with the T-die body to store and transport the resin melt. have. In addition, the T-die cover 500 may have a funnel shape entirely surrounding the lower portion of the T-die body.

In one embodiment of the present invention, a fixing member may be provided on one or both of the T-die body and the T-die cover so that the T-die cover is detachably coupled to the lower portion of the T-die body. . The fixing may be performed in the same manner as, but not limited to, sliding, bonding, interlocking, mating, bonding, riveting, and screwing between the T-die body and the T-die cover, but are not limited thereto. no. In one embodiment of the present invention, the T-die body and the T-die in such a way that a groove is formed in the engagement position of the T-die body, and a protrusion capable of engaging the groove is formed in the engagement position of the T-die cover. The cover can be combined.

In one embodiment of the invention, the T-body 610 and the T-die cover 620 in the T-die 600 for the extruder, as shown in Figure 6, the side inner wall of the T-die cover 610 The T-die body 710 and the T-die cover 720 in the extruder T-die 700 are designed to be in contact with the T-die body 620 or as shown in FIG. 7. Only a portion of the side inner wall of the die cover 710 may be designed to contact the T-die body 720, that is, the bottom of the T-die body 710 does not touch the bottom surface of the T-die cover 720. have.

The detachable cover may be a molded article made from a release heat-resistant polymer such as polytetrafluoroethylene, a release-treated metal, a tungsten-treated metal, more specifically a tungsten-treated tin, but is not limited thereto. . The surface tension of the metal may be lowered by the release treatment or the tungsten treatment.

According to one embodiment of the present invention, there is provided a T-die for an extruder, to which a peelable heat resistant tape is applied to the lower surface of the detachable cover.

According to an embodiment of the present invention, a peelable heat resistant tape is applied to a lower surface of the detachable cover, and the peel-off is possible to the entire lower surface of the lower surface of the detachable cover except for a portion having a discharge passage. Provided is a T-die for an extruder to which a heat resistant tape is applied.

According to an embodiment of the present invention, a peelable heat resistant tape is applied to a lower surface of the detachable cover, and the peel off possible portion of the lower surface of the lower surface of the detachable cover except for a portion having a discharge passage. Provided is a T-die for an extruder to which a heat resistant tape is applied.

The peel-off heat resistant tape has an adhesive surface formed on only one surface thereof, and the adhesive surface of the peelable heat resistant tape may be applied to the lower surface of the detachable cover.

In the present specification, 'tape' means at least one surface of a solid shape that is adhereable to at least one surface thereof, and may have not only a two-dimensional planar shape but also a three-dimensional solid shape.

In one embodiment of the invention the heat resistant tape may comprise a portion at least a portion of which is not attached to the T-die so that it may be more easily peeled off from the T-die at the point where peel off is necessary after application. That is, the heat resistant tape can have a grip portion that is not attached to the T-die and can be easily peeled off from the T-die by forcing the grip to be detached by hand or with a machine. .

In one embodiment of the invention 'heat resistance' of a heat resistant tape means having a glass transition temperature that can be peeled off without being affected by the resin melt in the T-die for the extruder. For example, the heat resistant tape may be one having a glass transition temperature in the range of 250 ° C to 900 ° C. In one embodiment of the present invention, the heat resistant tape capable of satisfying both such heat resistance and peel off resistance may be made of an adhesive polymer. Alternatively, the heat resistant tape may include a tape substrate and an adhesive layer formed on one surface of the substrate. Polyimide or polyamideimide is preferred as the raw material of the adhesive polymer or tape base material. An adhesive layer may be formed on one surface of the tape substrate to be adhereable to the T-die.

In one embodiment of the present invention, when at least 5 foreign bodies having a diameter of 1.5 mm or more are formed on the outer surface of the T-die or at a predetermined period determined by the user, or at a desired time by the user, the detachable contaminated by drool is detachable. A method of preventing T-die drool is provided by replacing the T-die cover with a clean new one.

According to one embodiment of the present invention, the bottom surface of the T-die cover at the time when five or more foreign bodies having a diameter of 1.5 mm or more are formed on the exterior of the T-die or at a predetermined period of time defined by the user or at a time desired by the user. The heat resistant tape applied to the substrate can be removed and a new heat resistant tape applied to the bottom surface of the T-die cover. The heat resistant tape can be replaced more frequently than the removable cover, keeping the T-die outlet perimeter clean.

Hereinafter, the present invention will be described in more detail by the following examples. The following examples are intended to illustrate embodiments of the invention and are not intended to limit the invention thereto.

Comparative example  One

Polyolefin is a high density polyethylene, its weight average molecular weight is 300,000 and the melting temperature is 135 ℃. The diluent used was liquid paraffin oil with a kinematic viscosity of 40 cSt at 40 ° C.

The weight ratio of the high density polyethylene and the liquid paraffin oil was 30:70. Trimethoxyvinylsilane was used as the vinylsilane, and the content of trimethoxyvinylsilane was 2.0 parts by weight based on 100 parts by weight of the total of high density polyethylene and liquid paraffin oil. As an initiator, 100 parts by weight of 2,5-dimethyl-2,5-di (tert-butylperoxy) benzene (2,5-dimethyl-2,5-di (tert-butylperoxy) hexane) trimethoxyvinylsilane 2 parts by weight, dibutyl tin dilaurate (dibutyl tin dilaurate) as a catalyst was added 2 parts by weight based on 100 parts by weight of trimethoxyvinylsilane. After the above components were introduced into a twin screw extruder (manufactured by EM / 320H Co., Ltd.), the mixture was kneaded to make a polyethylene sheet and simultaneously reacted by extrusion to prepare a silane-grafted polyethylene sheet.

The silane grafted polyethylene solution thus prepared was passed through a die and a cold casting roll to form a sheet, and then, after MD stretching, biaxial stretching was performed using a tenter-type stretching machine of TD stretching. MD draw ratio and TD draw ratio were 5.5 and 5.0 times, respectively. The stretching temperature was 105 ° C. for MD, 125 ° C. for TD, and extruded through a T-die (manufactured by CLOEREN INCORPORATED, model name: EPOCH III).

Liquid paraffin was extracted from the sheet thus obtained with methylene chloride, and heat-fixed at a draw ratio of 1.5 to 1.4 times at 126 ° C. to prepare a porous membrane. The resulting porous membrane was placed in a constant temperature and humidity chamber at 85 ° C. and 85% humidity for 48 hours to undergo crosslinking to prepare a crosslinked polyethylene sheet having a thickness of 12 μm.

After mixing Al ₂ O ₃ particles / cyanoethyl polyvinyl alcohol / PVDF-HFP / acetone = 16.0 / 0.2 / 3.8 / 80 weight ratio to prepare a slurry for forming a porous coating layer.

The slurry for forming a porous coating layer prepared above was coated with a thickness of 4.0 μm on each of both sides of the crosslinked polyethylene sheet in an atmosphere of about 65% relative humidity, and dried at 60 ° C. to obtain a composite membrane. The total thickness of the obtained composite membrane was 20.0 μm.

Comparative example  2

A silane-grafted polyethylene sheet was prepared in the same manner as in Comparative Example 1 except that a detachable T-die cover made of tungsten release-treated tin as shown in FIG. To prepare a composite membrane.

Comparative example  3

A silane-grafted polyethylene sheet was prepared in the same manner as in Comparative Example 1 except that a heat-resistant polymer tape (polyimide) cut to the shape of the lower surface of the T-die was applied to the lower surface of the T-die. Composite membranes were prepared. The peel-off heat resistant tape was replaced with a new one when the T-die appearance had five or more foreign bodies having a diameter of 1.5 mm or more.

Example  One

A detachable T-die cover made of tungsten release-treated tin as shown in FIG. 5 is applied to the bottom of the T-die, and a peel-off heat resistant tape having an adhesive layer on one side of the tape substrate of polyimide material is described. A silane-grafted polyethylene sheet was prepared in the same manner as in Comparative Example 1 except that the T-die cover was cut into a lower surface shape and applied to the lower surface of the T-die cover, thereby manufacturing a composite membrane. The detachable cover and peelable heat resistant tape were replaced with a new one when the T-die appearance had five or more foreign bodies with a diameter of 1.5 mm or more.

Evaluation example :

The silane grafted polyethylene sheets obtained in Comparative Examples 1 to 3 and Example 1 were evaluated by the following method, and the results are shown in Table 1.

(1) die drool evaluation

As an item for evaluating an external drool phenomenon, when five or more foreign bodies having a diameter of 1.5 mm or more were detected, it was determined that a die drool had occurred.

(2) Appearance of T-die Sheet

As an item for evaluating the internal drool phenomenon, when five or more shark lines were generated in the appearance of the sheet obtained immediately after the T-die step according to Example 1 and Comparative Examples 1 to 3 for 6 hours, it was evaluated as defective. If less than, it was evaluated as good.

(3) State of crosslinked polyethylene sheet

Nine pieces of 100 mm × 100 mm sheets were cut out from the biaxially stretched sheets of the crosslinked polyethylene sheets obtained in Examples 1 and Comparative Examples 1 to 3, and the test pieces were left to shrink for 60 minutes in an oven at 135 ° C. for shrinkage. The length [X] and [Y] (unit: mm) of the sheet | seat piece of the later longitudinal and horizontal direction were measured. About the value computed from the following formula, the number of sheet pieces which satisfy | filled conditions was measured, and the following reference | standard evaluated.

 1.6 = 100 / [X] = 4.0, and 1.6 = 100 / [Y] = 4.0 ..... Formula (A)

Good: 7 or more sheets of sheet satisfying equation (A)

Fracture: Less than 3 pieces of sheet meet the formula (A)

(4) Extruder continuous operation time

The extruder continuous operation time until five or more foreign substances with diameter 1.5 mm or more were detected was measured.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Die drool phenomenon Occur Occur Not Occurred Not Occurred Appearance of T-die Sheet Bad Good Bad Good State of crosslinked polyethylene sheet Breaking Good Good Good Extruder continuous operation time 4.5 hours 18 hours 14.5 hours Continuous operation possible until replacement (over 48 hours)

From the above, in Comparative Example 1, it was confirmed that a die drool phenomenon occurred on the T-die, and a shark line appeared on the T-die sheet appearance due to the internal drool. In addition, fracture occurred at the time of stretching due to the foreign matter contained in the sheet.

In Comparative Example 2, the detachable T-die cover was applied to the T-die and the internal drool phenomenon was solved, and the appearance of the T-die sheet was evaluated as good, but the external drool phenomenon was observed on the lower surface of the T-die cover. It was confirmed that this occurred. In addition, no fracture occurred at the time of stretching the sheet.

In Comparative Example 3, a peel-off heat resistant tape was applied to the lower surface of the T-die so that no external drooling occurred, but foreign matters grown inside the T-die were pushed to the discharge port, resulting in uneven sheet appearance. In addition, it is thought that break did not generate | occur | produce at the time of extending | stretching a sheet.

In Example 1, no die drool occurred, no damage to the appearance of the sheet due to foreign matter inside the T-die, and no shark line occurred in the T-die sheet.

While the embodiments of the present invention have been described above, it will be understood by those skilled in the art that the present invention may be embodied in other specific forms without changing the technical spirit or essential features thereof. will be.

Claims (10)

In the T-die for an extruder which discharges a resin melt,
A T-die body constituting an upper portion of the T-die; And a T-die cover constituting a lower part of the T-die and being tightly coupled to the T-die body and detachable from the T-die body.
The T-die body and the T-die cover are in fluid communication,
Peel-off heat-resistant tape is applied to the bottom surface of the T-die cover,
Wherein said peelable heat resistant tape is attached to a portion of the bottom surface of said T-die cover
T-die for extruder.
The method of claim 1,
One or both of the T-die body and the T-die cover is provided with a fixing member is coupled to the T-die for the extruder.
The method of claim 2,
The groove is formed in the coupling position of the T-die body, and the projection for engaging the groove is formed in the coupling position of the T-die cover T-die for the extruder.
The method of claim 1,
Wherein said T-die cover is formed from a heat resistant material.
The method of claim 1,
Wherein the T-die cover is formed from a release treated polytetrafluoroethylene or a release treated metal or tungsten treated tin.
The method of claim 1,
The peelable heat resistant tape comprises a tape substrate of polyimide or polyamideimide material; And an adhesive layer formed on one surface of the tape substrate.
The method of claim 1,
And said peel-off heat resistant tape is a tape made of polyimide or polyamideimide.
delete The method of claim 1,
Wherein said peelable heat resistant tape is attached except for a portion of a discharge flow path of a lower surface of said T-die cover.
An extruder provided with the T-die for extruders of Claim 1.

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