KR101928338B1 - Extruded Polystyrene foam having closed cell of ellipse type and manfacturing method thereof - Google Patents

Abstract

The present invention relates to an extruded expanded polystyrene foam having an elliptically closed cell and a method for producing the extruded expanded polystyrene foam, and a method of manufacturing the extruded expanded polystyrene foam according to an embodiment of the present invention includes the steps of: providing a polystyrene resin composition; Melting, foaming and extruding the polystyrene resin composition; And pressing the extruded foamed polystyrene foam to form a closed cell into an elliptic shape having a major axis in the width direction of the extruded expanded polystyrene foam and having a minor axis in the thickness direction.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruded foamed polystyrene foam having an elliptically closed cell and an extruded foamed polystyrene foam having a closed cell of an ellipse type and a manfacturing method,

The present invention relates to an extruded expanded polystyrene foam having an elliptically closed cell and a method for producing the extruded expanded polystyrene foam, and more particularly to an extruded expanded polystyrene foam having an elliptically closed cell having excellent heat resistance and a method for producing the same.

Expanded polystyrene boards have been widely used in order to provide external beauty and insulation in various industries such as buildings.

Although it is ideal that the thermal conductivity of the material of the heat insulating material is small, it is difficult to secure an ideal thermal conductivity with the material itself, so that it is formed into a porous material and the heat insulating property of the air in the pore is utilized.

As a typical method of producing expanded polystyrene insulation, there are bead method and extrusion method. Expanded polystyrene produced by bead method is commonly known as EPS and is also known as styrofoam which is a trade name of a specific company. The bead method is a given name because the polystyrene beads are foamed to produce a heat insulator.

The extrusion method is a method in which a foaming agent and other additives are mixed with a polystyrene resin, and the resulting mixture is melt-processed, extruded and cooled.

In order to compensate the thermal conductivity, such a foamed insulating material forms an air layer hole called a cell. When forming such a cell in the foamed insulating material, it is advantageous in terms of thermal conductivity, but when the foamed insulating material is produced with a large thickness, . When the size of the cell in the foam insulation increases, the foam insulation easily shrinks or expands according to the temperature change. Generally, foaming heat insulation material is produced at a thickness of about 20 to 250 mm. In order to produce foaming insulation material thicker than this, a separate combination process must be additionally performed.

Korean Patent Laid-Open Publication No. 2016-0038163 (Extruded Styrene Foam Excellent in Heat Insulation Using a Foaming Agent Containing Carbon Dioxide and Method for Producing the Same) Korean Patent Laid-Open Publication No. 2013-0052484 (expanded polystyrene excellent in heat insulation and workability, method for producing the same, and foam formed therefrom)

It is an object of an embodiment of the present invention to provide an extruded expanded polystyrene foam having an elliptically closed cell having excellent heat resistance performance and a method of manufacturing the same.

One embodiment of the present invention relates to a method for producing a polystyrene resin composition, Melting, foaming and extruding the polystyrene resin composition; And pressing the extruded foamed polystyrene foam to form a closed cell into an elliptic shape having a major axis in the width direction of the extruded expanded polystyrene foam and a minor axis in the thickness direction, And a method for producing the extruded expanded polystyrene foam.

And the ratio of the short axis to the long axis of the closed cell deformed into the elliptical shape in the press forming step is 0.8 or less.

The press molding may be performed by passing the extruded foamed polystyrene foam onto a pressure roller disposed above and below the extruded foamed polystyrene foam.

The pressure applied by the pressure roller is 70 to 284 psi, and the temperature is 80 to 110 ° C.

The press-molding may be performed using an extruder having a discharge port having a cross-sectional area smaller than the cross-sectional area of the extruder in the extruding step.

The speed of the extruded foamed extruded expanded polystyrene foam can be increased by disposing a rotating roller in front of the discharge port.

The pressure applied by the rotating roller is 284 psi or less, and the temperature is 40 to 80 ° C.

The melting, foaming and extrusion may be performed continuously through a primary extruder and a secondary extruder having a lower temperature than the temperature of the primary extruder.

Another embodiment of the present invention provides an extruded expanded polystyrene foam having an elliptically closed cell prepared by the above method by a method.

The extruded foamed polystyrene foam having an elliptic closed cell according to an embodiment of the present invention may have an elliptical shape of a closed cell, and the number of cells per unit volume may be increased to have excellent heat resistance. The size of the cell, the density of the cell per unit volume, and the shape thereof are very important factors for the thermal resistance characteristics. In the extruded expanded polystyrene foam according to one embodiment of the present invention, the closed cell is deformed into an elliptical shape, So that the thermal resistance characteristics can be improved.

In addition, even if the thickness of the extruded expanded polystyrene foam is increased, the closed cells of the inner cells are formed to have an elliptical long axis in the width direction, so that the ratio of the cells per unit volume is increased and the heat resistance of the extruded expanded polystyrene foam Can be improved.

In addition, even if the thickness is increased, the extruded foamed polystyrene foam having a thickened thickness can be provided without any change in external shape such as shrinkage and expansion due to temperature change.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view schematically showing an apparatus used in the production of an extruded expanded polystyrene foam according to an embodiment of the present invention. Fig.
2 is a conceptual diagram schematically showing a pressurizing device used for producing an extruded expanded polystyrene foam according to an embodiment of the present invention.
3 is a conceptual view schematically showing a pressurizing device used for producing an extruded expanded polystyrene foam according to an embodiment of the present invention.
4 is a conceptual diagram schematically showing an extruded expanded polystyrene foam produced according to an embodiment of the present invention.
5 is a photograph of the extruded expanded polystyrene foam produced in the comparative example.
6 is a photograph of the extruded foamed polystyrene foam produced according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. Therefore, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the following embodiments.

Throughout the description of the present invention, when a component is referred to as " comprising ", it means that it can include other components as well, without excluding other components unless specifically stated otherwise.

In the specification of the present invention, it is to be understood that when a step is located "on" or "before" another step, this is not only the case where a step is in a direct time series relationship with another step, And may have the same rights as in the case of an indirect temporal relationship in which the temporal order of the two phases can be changed.

The terms " about ", " substantially ", etc. used to the extent that they are used throughout the specification of the present invention are used in their numerical values or in close proximity to their numerical values when the manufacturing and material tolerances inherent in the meanings mentioned are presented, Is used to prevent unauthorized exploitation by an unscrupulous infringer of precise or absolute disclosures in order to aid in the understanding of the disclosure. The term " step " or " step of ~ " used throughout the specification does not mean " step for.

The present invention relates to an extruded expanded polystyrene foam having an elliptically closed cell and a method for producing the extruded expanded polystyrene foam, and a method for producing the extruded expanded polystyrene foam according to the present invention comprises the steps of: providing a polystyrene resin composition; Melting, foaming and extruding the polystyrene resin composition; And pressing the extruded foamed polystyrene foam to form a closed cell into an elliptic shape having a major axis in the width direction of the extruded expanded polystyrene foam and having a minor axis in the thickness direction.

An extruded expanded polystyrene foam having an elliptic closed cell according to an embodiment of the present invention (hereinafter, also referred to as an extruded expanded polystyrene foam) can be produced by the above-described method. The extruded expanded polystyrene foam according to the present invention is formed in an elliptical shape of a closed cell, so that the number of cells per unit volume can be increased to have excellent heat resistance.

In general, extruded expanded polystyrene foam foamed in an extruder tends to be deformed into an elliptical shape in which a closed cell inside is thickened in the thickness direction of extruded expanded polystyrene foam. This is attributed to the deterioration of the thermal resistance characteristic per unit thickness.

That is, the size of the cell, the density of the cell per unit volume, and the shape thereof are very important factors for the thermal resistance characteristic. According to one embodiment of the present invention, the closed cell is deformed into an elliptical shape, so that the ratio of the cells per unit volume is increased, and thus the thermal resistance characteristic can be improved.

4, the closed cell 101 of the extruded expanded polystyrene foam 100 according to the embodiment of the present invention has a short axis (b, y axis) in the long axis (a, x axis direction) Direction) may be 0.8 or less. In the present invention, the x-axis direction and the z-axis direction can be understood as the width, the width or the length of the extruded expanded polystyrene foam, and the y-axis direction can be understood as the thickness of the extruded expanded polystyrene foam.

The smaller the ratio (b / a) of the minor axis to the major axis of the elliptical closed cell 101 is, the better the heat resistance characteristic, i.e., the heat insulating performance can be improved. According to an embodiment of the present invention, the ratio (b / a) of the short axis to the major axis of the elliptical closed cell 101 may be 0.8 or less, preferably 0.7 or less, or 0.4 to 0.7. If the ratio (b / a) of the minor axis to the major axis of the elliptical closed cell 101 exceeds 0.8, the improvement in the heat insulating performance may be insufficient, and when the pressure is forcibly pressed to be less than 0.4, So that the heat resistance characteristic may be lowered.

Hereinafter, a method for producing an extruded expanded polystyrene foam according to an embodiment of the present invention will be described in detail.

Fig. 1 is a schematic view schematically showing an apparatus used in the production of an extruded expanded polystyrene foam according to an embodiment of the present invention, Figs. 2 and 3 are used for producing extruded expanded polystyrene foam according to an embodiment of the present invention Fig. 2 is a conceptual diagram schematically showing a pressurizing device. 4 is a conceptual diagram schematically showing an extruded expanded polystyrene foam produced according to an embodiment of the present invention.

Referring to FIG. 1, the polystyrene resin composition may be prepared and then introduced into the first extruder 10.

According to one embodiment of the present invention, the polystyrene resin composition may be continuously foamed and extruded through the first extruder 10 and the second extruder 20. [

The extruded foamed polystyrene foam according to one embodiment of the present invention is made of a polystyrene resin as a main component, and may include an additive for extrusion foaming.

The polystyrene resin composition is not particularly limited and may include, for example, a polystyrene resin, a nucleating agent, a flame retardant, and a foaming agent.

The polystyrene resin is a thermoplastic polymer that can be used in an extrusion process and is not particularly limited. For example, polystyrene having a molecular weight of 200,000 to 350,000 g / mol can be used.

Talc (TALC), calcium carbonate, silica, or the like can be used as the nucleating agent usable in the present invention. The nucleating agent can be used to reduce or uniformize the size of the foamed cells and can complement the heat insulating properties of extruded expanded polystyrene foam.

The content of the nucleating agent may be 0.1 to 3 parts by weight based on 100 parts by weight of the polystyrene resin. If the content of the nucleating agent is less than 0.1 parts by weight, the closed cell may not be sufficiently formed and the heat insulating property may be deteriorated. If the content is more than 3 parts by weight, it may be difficult to deform the closed cell into an elliptical shape.

The flame retardant that can be used in the present invention is not particularly limited. For example, a bromine-based flame retardant may be used.

As the bromine-based flame retardant, hexabromocyclododecane (HBCD), which is an organic halogen-based flame retardant, may be used. The flame retardant may be added in powder form or in pellet form.

The bromine (Br) component contained in the brominated flame retardant penetrates into the foamed polystyrene foam board to generate a nonflammable gas, thereby causing digestion. The brominated flame retardant activates the flame retarding mechanism of the expanded polystyrene foam board so that the expanded polystyrene foam itself is digestible.

The content of the flame retardant may be 1 to 8 parts by weight based on 100 parts by weight of the polystyrene resin. When the content of the flame retardant is less than 1 part by weight, it may be difficult to secure flame retardancy. When the content of the flame retardant exceeds 8 parts by weight, it may be difficult to deform the closed cell into an elliptical shape.

The blowing agent that can be used in the present invention may be at least one selected from the group consisting of HCFC-22 (chlorodifluoromethane, Monochloro difluoro, etc.) as a foaming gas of gaseous ethanol, isobutane, butane gas, carbon dioxide, etc. and / HFC-152a (difluoroethane), HFC-134a (tetrafluoroethane), ethanol, and the like are used as the HFC (methane), HCFC-142b (chlorodifluoroethane, Monochloro difluoro ethane) Dimethyl-ether (DME) and the like.

The blowing agent may be used in a liquefied state.

The content of the foaming agent may be 0.2 to 10 parts by weight based on 100 parts by weight of the polystyrene resin. If the content of the foaming agent is less than 0.2 parts by weight, the foam may not be sufficiently foamed. If the content of the blowing agent is more than 10 parts by weight, the closed cell may be broken in the extrusion process or the pressure molding process after extrusion.

According to one embodiment of the present invention, the polystyrene resin may be first put into the first extruder 10, and the nucleating agent and the flame retardant may be mixed. Or a polystyrene resin, a nucleating agent and a flame retardant may be mixed, and the mixture may be introduced into a primary extruder for melting and foaming.

When the polystyrene resin composition is melted in the primary extruder 10, the foaming agent can be dispersed among the melts.

The foaming agent may be introduced under the conditions that the pressure inside the primary extruder is from 1990 to 3130 psi and the temperature is from 170 to 210 ° C.

If the pressure applied to the primary extruder exceeds 3130 psi or the temperature value is less than 170 캜, the extruder may be overloaded or the extruder may not be able to melt due to the limit of the extruder.

Further, when the pressure value applied to the primary extruder is less than 1,990 psi or the temperature value exceeds 210 캜, the carbon dioxide blowing agent is not stably dispersed and mixed in the polystyrene resin particles, so that a foam having high density and high thermal conductivity is manufactured There is a concern.

Next, foaming and extrusion can be performed while passing through the secondary extruder 20.

The pressure of the secondary extruder may be from 540 to 626 psi and the temperature may be from 90 to 110 캜.

If the pressure value exceeds 626 psi or the temperature value is less than 110 캜 during extrusion molding, the abrasion is promoted due to the limit of the extrusion facility, while if the pressure value is less than 540 psi or the temperature value exceeds 120 캜, Opening of the foaming agent may cause an open cell to be formed in the foam, which may result in deterioration of the surface quality of the molded article.

According to one embodiment of the present invention, the melting, foaming and extrusion of the polystyrene resin composition can be continuously carried out through a primary extruder and a twin extruder.

After passing through the discharge port 21 of the secondary extruder 20, a calibrator 30 and a haul-off 40 can be passed to make the surface and side of the extruded expanded polystyrene foam uniform. have.

When passed through the calibrator 30 and the shallow off 40, the pressure may be between 900 and 1000 psi and the temperature may be between 100 and 120 < 0 > C.

If the pressure value at the time of passing through the calibrate 30 and the shallow 40 is more than 1000 psi or the temperature value is less than 100 캜, the surface of the extruded expanded polystyrene foam may not be uniformly treated and the pressure may be less than 900 psi If the temperature exceeds 120 ° C, thermal deformation may occur on the surface of the extruded foamed polystyrene foam and the physical properties may be deteriorated.

Next, the extruded foamed polystyrene foam may be pressure-molded to transform the closed cell into an elliptical shape.

According to one embodiment of the present invention, the closed cell existing inside the extruded expanded polystyrene foam can be press-molded so as not to break and form an elliptical shape.

4, pressure is applied to the extruded foamed polystyrene foam to deform the closed cell into an elliptical cell 101 having a major axis (a, x axis direction) and a minor axis (b, y axis direction) .

In the present invention, the x-axis direction and the z-axis direction can be understood as the width, the width or the length of the extruded expanded polystyrene foam, and the y-axis direction can be understood as the thickness of the extruded expanded polystyrene foam.

The pressure molding method is not particularly limited, and a predetermined temperature and pressure may be applied so that the diameter of the closed cell with the thickness direction of the polystyrene foam as a reference (y-axis direction) decreases.

According to an embodiment of the present invention, the pressurizing chamber 50 having the pressure rollers R ₁ and R ₂ as shown in FIG. 2 can be used.

The extruded foamed polystyrene foam having passed through the calibrator 30 and the shallow 40 can be moved to the pressure chamber 50 and passed through the pressure rollers R ₁ and R ₂ .

The pressure rollers R ₁ and R ₂ may be disposed at the upper and lower portions of the extruded foamed polystyrene foam 100 and allow the extruded foamed polystyrene foam 100 to pass between the pressure rollers. The extruded foamed polystyrene foam 100 can be pressed by rotating the pressure rollers R ₁ and R ₂ .

According to an embodiment of the present invention, as shown in FIG. 2, the pressure rollers R ₁ and R ₂ disposed at the upper and lower portions can be disposed at the upper and lower portions, respectively, so as not to be centered. The center of the upper pressure roller (R ₁₎ (O1), leaving the center (O2), with a predetermined distance (△ t) of lower pressing rollers may be arranged spaced apart. Accordingly, by controlling the pressure applied to the extruded foamed polystyrene foam 100, the extruded expanded polystyrene foam can be deformed into an elliptical shape without breaking the closed cell, and the ratio of the major axis to the minor axis can be controlled.

The pressure applied by the pressure roller (R ₁ , R ₂ ) may be 70 to 284 psi, and the temperature may be 80 to 110 ° C. If the pressure exceeds 284 psi, the closed cell may be broken and deformed into an open cell upon excessive pressure. Further, when the pressure is lowered to less than 70 psi, the compression effect of the extruded foamed polystyrene foam is insufficient, and deformation of the closed cell may be difficult.

In general, when the extruded expanded polystyrene foam extruded from an extruder is increased in thickness, the shape of the closed cell inside tends to be elliptical in the thickness direction. This is considered to be a factor for lowering the thermal resistance characteristic per unit thickness.

That is, the size of the cell, the density of the cell per unit volume, the shape, and the directionality of the closed cell are very important factors for the thermal resistance of the extruded expanded polystyrene foam.

According to one embodiment of the present invention, the closed cell of the extruded expanded polystyrene foam has an elliptic long axis in the width direction, thereby increasing the ratio of the cells per unit volume and improving the heat resistance of the extruded expanded polystyrene foam due to its orientation .

Further, according to one embodiment of the present invention, the extrusion foamed polystyrene foam can be extruded and the ejection speed can be controlled to apply pressure to the extruded foamed polystyrene foam.

Referring to FIG. 3, the extruder can be performed using an extruder having a smaller cross-sectional area of the discharge port 21 than the cross-sectional area of the secondary extruder 20. Accordingly, the speed V2 of the to-be-discharged is faster than the speed V1 of the secondary extruder 20, so that the pressure can be applied to the extruded polystyrene foam.

For example, the discharge port may have a size of 2 to 10 mm in length and 150 to 400 mm in width, and the extruder may have a size of 5 to 15 times of the size thereof.

According to an embodiment of the present invention, a rotary roller R ₃ can be disposed in front of the discharge port 21 of the secondary extruder. When the rotating roller (R ₃ ) is rotated, the extruded expanded polystyrene foam discharged from the extruded expanded polystyrene foam is pulled and the speed of the extruded expanded polystyrene foam extruded can be increased. In addition, pressure can be applied by the rotating roller.

The pressure applied by the rotating roller may be 284 psi or less, and the temperature may be 40 to 80 캜.

When the pressure is applied to the extruded expanded polystyrene foam by the roller, the closed cell can be deformed into an elliptical shape and the overall uniformity of the extruded expanded polystyrene foam can be improved.

4 is a conceptual diagram schematically showing an extruded expanded polystyrene foam produced according to an embodiment of the present invention.

4, the extruded foamed polystyrene foam 100 may have an elliptical closed cell 101, and the ratio of the short axis to the major axis of the ellipse (b / a, a: length of the major axis, b: Length) may be 0.8 or less.

As described above, the extruded foamed polystyrene foam having an elliptical closed cell according to an embodiment of the present invention has an elliptical long axis in the width direction (x-axis direction) of the foam, so that the ratio of cells per unit volume The heat resistance of the extruded foamed polystyrene foam can be improved owing to its directionality.

The extruded foamed polystyrene foam produced by the above-mentioned method can be cut and cut into a standardized size to be used according to the use area through the cut part.

As described above, according to one embodiment of the present invention, by adjusting the shape of the closed cell, it can be manufactured by increasing the thickness of the extruded foamed polystyrene foam. It is possible to provide an extruded foamed expanded polystyrene foam having an increased thickness without a separate joining process without easily changing the external shape such as shrinkage and expansion due to temperature change even if it is manufactured by increasing the thickness.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.

[Example]

Example  One

1 kg of a flame retardant HBCD and 0.2 kg of a nucleating agent talc were added to 100 kg of a polystyrene resin (product of '25SPE' manufactured by LG Chem) and melted. Then, HFC-134A was obtained under a pressure of 2844 psi (about 200 kgf / 2 kg of 152A and 6 kg of HCFC22 and 142b were charged and extruded and foamed at a secondary extrusion temperature of 100 DEG C and a pressure of 597 psi to prepare an extruded expanded polystyrene foam having a thickness of 100 mm.

The calibrator and how-off equipment was passed to adjust the thickness and shape of the foam produced.

The extruded foamed polystyrene foam having passed through the calibrator and the way off equipment was subjected to a pressurizing process using a pressure roller as shown in Fig. At this time, the temperature condition was maintained at 90 DEG C, the pressure was 142 psi, and the process time was 3 hours.

Example  2

3, except that the shape of the ejection opening was different during the secondary extrusion. More specifically, the cross-sectional area of the discharge port of the secondary extruder was smaller than that of the secondary extruder. The size of the rectangular discharge port was 2 mm in length and 300 mm in width.

At this time, a rotary roller was disposed on the side of the discharge port to additionally apply pressure. The pressure applied by the rotating roller was 213 psi and the temperature was 60 deg.

Comparative Example

The procedure of Example 1 was the same as that of Example 1, except that the pressure was not applied after passing through the calibrator and howl equipment.

[evaluation]

The surface state of the extruded expanded polystyrene foam prepared in Example 1 and Comparative Example was inspected, and the density and the thermal conductivity were measured. The results are shown in Table 1 below. The thermal conductivity was measured according to Korean Industrial Standards KS L 9016 at an average temperature of 20 ° C.

division Example 1 Comparative Example density 32 g / l 31 g / l Initial thermal conductivity 0.024 W / mK 0.029 W / mK surface Good Good

The extruded expanded polystyrene foam prepared in Example 1 and Comparative Example all had a closed cell, but the heat resistance of Example 1 was improved by about 15% compared with Comparative Example.

FIG. 5 is a photograph of the extruded expanded polystyrene foam produced in the above Comparative Example, and FIG. 6 is a photograph of the extruded expanded polystyrene foam produced in Example 1. FIG.

Referring to FIGS. 5 and 6, it can be seen that the closed cell of FIG. 6 has an elliptical shape in comparison with the closed cell of FIG.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but many variations and modifications may be made without departing from the scope of the present invention. It is evident that many variations are possible by those skilled in the art. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

10: Primary extruder 20: Secondary extruder
30: calibrator 40: howl off
50: Pressurizing chamber 100: Extruded expanded polystyrene foam
101: Oval Closed Cell

Claims (9)

Providing a polystyrene resin composition;
Melting, foaming and extruding the polystyrene resin composition; And
And extruding the extruded expanded polystyrene foam to form a closed cell into an elliptic shape having a major axis in the width direction of the extruded expanded polystyrene foam and a minor axis in the thickness direction,
Wherein the press molding is performed by passing the extruded foamed polystyrene foam through a pressure roller disposed above and below the extruded foamed polystyrene foam. ≪ Desc / Clms Page number 21 >
The method according to claim 1,
Wherein the ratio of the minor axis of the closed cell to the elliptical shape in the pressure forming step is 0.8 or less.
delete The method according to claim 1,
Wherein the pressure applied by the pressure roller is 70 to 284 psi and the temperature is 80 to 110 ° C.
The method according to claim 1,
Wherein the press molding is performed using an extruder having a discharge port having a cross sectional area smaller than a cross sectional area of the extruder in the extrusion step. ≪ RTI ID = 0.0 > 21. < / RTI >
6. The method of claim 5,
Wherein a rotating roller is disposed in front of the discharge port to increase the speed of the extruded expanded polystyrene foam extruded out.
The method according to claim 6,
Wherein the pressure applied by the rotating roller is 284 psi or less and the temperature is 40 to 80 占 폚.
The method according to claim 1,
Wherein the melting, foaming, and extrusion are continuously performed through a primary extruder and a secondary extruder having a lower temperature than the temperature of the primary extruder.
delete

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