JP2011005706A - Extrusion molding method of non-foamed molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the extrusion molding method of non-foamed moldings for increasing the molding speed, in the extrusion molding method using thermoplastic resin with heat conductivity of 0.2 W/(m K) or less.SOLUTION: In the extrusion molding method of non-foamed moldings using the thermoplastic resin with the heat conductivity of 0.2 W/(m K) or less, after extruding heated melt of the thermoplastic resin is extruded from an extruder and dies, the extruded heated-softened molding is introduced into the introducing path of a sizing device to which an antifreezing solution kept at -10 to 10°C is passed as a cooling medium, the heated-softened molding is brought into contact with the periphery of the introducing path serving as a cooling face, restricted to a given size, and cooled and solidified. The molding thus cooled and solidified is pulled out of the sizing device by a pulling out roll.

Description

  The present invention relates to a method for extruding a non-foamed molded article made of a thermoplastic resin.

Conventionally, as one of molding methods in a non-foamed resin molded product, a thermoplastic resin is put into an extruder to form a heated melt, and the heated melt is extruded into a predetermined shape from a die and then extruded. An extrusion molding method is used in which a heat-softened molded product is cooled and solidified between the die and the draw roll while the heat-softened molded product is pulled by a draw roll. When the production capacity is improved by the extrusion molding method, a method of increasing the molding speed mainly by increasing the cooling speed is employed.
In the water cooling device for an extruded product in the extrusion device described in Patent Document 1, water is used as a coolant, and water is passed through a water tank to cool and solidify the molded product in a heat-softened state. Is adopted. And in this patent document 1, while increasing the circulation amount of the water per unit time, and making the water temperature in the aquarium which tends to become non-uniform with the increase in the circulation amount, the cooling rate is improved. ing.
In the method and apparatus for producing a thermoplastic resin extruded product described in Patent Document 2, water is used as a refrigerant, and heat exchange is performed through the inner wall surface of the apparatus, whereby the heat-softened molded article is cooled and solidified. Both cooling and direct cooling in which water as a refrigerant is brought into direct contact with the surface of the molded product are employed. Specifically, by providing a plurality of cooling units, the first cooling unit is indirect cooling, and the second and subsequent cooling units are directly cooled, thereby improving the cooling efficiency and improving the cooling rate. .

JP 2002-355881 A JP 2001-129873 A

However, direct cooling by the above-described conventional extrusion molding method is superior to indirect cooling because the refrigerant is directly brought into contact with the surface of the molded product. However, in some thermoplastic resins such as polyolefin, for example, There is a problem that the usable resin is limited such that a molding failure occurs without being stabilized in a desired shape. On the other hand, indirect cooling does not have a problem that the resin that can be used is limited, but it is necessary to set the minimum temperature higher than 10 ° C. in order to prevent freezing of water used for the refrigerant. There is a problem that it is difficult to improve the cooling rate. In particular, in the case of a thermoplastic resin having a thermal conductivity of 0.2 W / m · K or less, that is, a low thermal conductivity, the internal heat accumulated inside the molded product is difficult to dissipate, and the molded product is caused by the internal heat. Since it becomes a softened state for a long time, from the viewpoint of suppressing molding defects, the pulling speed by the drawing roll has to be low (6 cm per minute for a foamed product with a thickness of 12 mm), and the molding speed is slow. there were.
The present invention has been made paying attention to such problems existing in the prior art. An object of the invention is to provide an extrusion method that can increase the molding speed in an extrusion method using a thermoplastic resin having a thermal conductivity of 0.2 W / m · K or less.

In order to achieve the above object, the invention of the non-foamed molded product extrusion molding method according to claim 1 uses a thermoplastic resin having a thermal conductivity of 0.2 W / m · K or less as a material and is non-foamed. After the extruded melt of the thermoplastic resin is extruded from an extruder and a die, the extruded heat-softened molded product is -10 to 10 ° C. An antifreeze liquid maintained at a temperature is introduced into an introduction path of a sizing device through which it is sent as a refrigerant. The gist is to cool and solidify while regulating, and pull out the cooled and solidified molded article from the sizing device by pulling it with a drawing roll.
The invention of the extrusion molding method for a non-foamed molded article according to claim 2 is for molding a non-foamed molded article using a thermoplastic resin having a thermal conductivity of 0.2 W / m · K or less as a material. Immediately after extruding the heated melt of the thermoplastic resin from an extruder and a die, the chilled water held at a temperature of 10 to 12 ° C. It introduces into the 1st introduction path of the sizing device currently sent as a refrigerant, makes the peripheral surface of this 1st introduction path into a primary cooling surface, and makes the molded product of a heat softening state contact with this primary cooling surface, and has a predetermined size. Of the sizing device in which the non-freezing liquid maintained at a temperature of −10 to 10 ° C. is passed as the refrigerant after the primary cooling is performed while the primary cooling is performed. Introduced into the introduction path, and the peripheral surface of the second introduction path is defined as a secondary cooling surface. Te, contacting the molding of unsolidified state on the secondary cooling surface is cooled and solidified, and summarized in that elicit this manner the molded product was cooled and solidified from the second introduction path pulled by the pull-out roll.
According to the extrusion molding method of the present invention, by using an antifreeze liquid as a refrigerant, a heat-softened molded product can be obtained by an indirect cooling method even for a thermoplastic resin having a thermal conductivity of 0.2 W / m · K or less. Since it can cool quickly, cooling time can be shortened. For this reason, it becomes possible to increase the pulling speed by the drawing roll, and it becomes possible to increase the forming speed.
In addition, in the indirect cooling method, cooling using chiller water as a refrigerant first, followed by cooling and solidification using an antifreeze liquid as a refrigerant may cause molding defects such as sink marks, warpage, cracks, etc. Can be suppressed.

The invention according to claim 3 is the invention of the method for extruding a non-foamed molded article according to claim 1 or 2, wherein the thermoplastic resin is polypropylene (PP), acrylic resin (PMMA), and polycarbonate. The gist is that it is at least one of (PC).
According to the extrusion molding method, it is possible to suitably increase the molding speed of the thermoplastic resin in which it is difficult to improve the molding speed. In particular, PP, which is a crystalline resin, is cooled and solidified by a direct cooling method, because the orientation of molecules is disturbed by rapid cooling and the shape cannot be determined. It is particularly useful in the extrusion method used.

The invention according to claim 4 is the invention of the extrusion molding method of the non-foamed molded product according to any one of claims 1 to 3, wherein the molded product has a thickness of 3 mm or less, The gist is to pull the object at a speed of not more than 2.0 m / min and not more than 3.0 m / min by a drawing roll.
According to the above extrusion molding method, it is possible to suitably control the cooling time based on the viewpoint of preventing the occurrence of molding defects by setting the thickness of the molded product to 3 mm or less. It is possible to suppress the occurrence of residual strain in the molded product by excessively pulling the molded product in the heat-softened state while accelerating.

  According to the present invention, in an extrusion molding method using a thermoplastic resin having a thermal conductivity of 0.2 W / m · K or less, an extrusion molding method capable of increasing the molding speed, a sizing device used in the method, and the method Extrudates produced by the method can be provided.

The schematic diagram which shows an extruder.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
〔Thermoplastic resin〕
In the present invention, a thermoplastic resin having a thermal conductivity of 0.2 W / m · K or less is used. For thermoplastic resins having a thermal conductivity exceeding 0.2 W / m · K, extrusion molding can be performed at a high molding speed without using the present invention, and thermoplasticity exceeding 0.2 W / m · K. When the present invention is applied to the resin, molding defects such as sink marks, warpage, and cracks may occur. In addition, about the thermal conductivity, the general physical property value by ASTM C 177 was mainly referred.
Specific examples of the thermoplastic resin having a thermal conductivity of 0.2 W / m · K or less include polyolefin (polypropylene (PP) (thermal conductivity: 0.12 W / m · K), polybutene as the crystalline resin. (PB) (thermal conductivity: 0.17 W / m · K), and the like. As an amorphous resin, acrylic resin (PMMA) (thermal conductivity: 0.19 W / m · K), polycarbonate (PC ) (Thermal conductivity: 0.19 W / m · K), polystyrene (PS) (thermal conductivity: 0.108 W / m · K), polyvinyl chloride (PVC) (thermal conductivity: 0.16-0. 17 W / m · K). Among these, PP and PB, which are crystalline resins, are difficult to cool and solidify by a direct cooling method, and thus the extrusion molding method of the present invention is useful.

  In the present invention, a recycled thermoplastic resin that is a recycled material (recycled material) of a thermoplastic resin can be used in addition to the new thermoplastic resin material (virgin material). The recycled thermoplastic resin refers to, for example, removing contaminants from waste products of the thermoplastic resin such as packaging film made of thermoplastic resin, packaging bag, packaging container, etc. It is obtained by recycling.

The regenerated thermoplastic resin has a tendency to lower its molecular chain by being cut in the process of heating and melting. When the molecular weight is lowered in this way, the melt viscosity is lowered and the physical properties of the resulting molded product are deteriorated. Therefore, rubber and / or elastomer may be added depending on the use of the molded body from the viewpoint of suppressing deterioration of physical properties.
Examples of the rubber and / or elastomer include polyester, polyacrylate, acrylic rubber (AR), butyl rubber, silicon rubber, urethane rubber (UR), fluoride rubber, polysulfide rubber, graft rubber, and butadiene rubber. (BR), polybutadiene, isoprene rubber (IR), polyisoprene, chloroprene rubber (CR), polyisobutylene rubber (IBR), polybutene rubber, thiocol rubber, polysulfide rubber, polyether rubber, epichlorohydrin rubber, norbornene terpolymer, Hydroxy or carboxy-terminated polybutadiene, partially hydrogenated styrene-butadiene block copolymer, chlorosulfonated rubber, isobutene-isoprene rubber (IIR), acrylate-butadiene rubber (ABR), styrene-butadiene Rubber (SBR), Acrylonitrile-butadiene rubber (NBR), Pyridine-butadiene rubber, Styrene-isoprene rubber (SIR), Styrene-ethylene copolymer, Polystyrene-polybutadiene-polystyrene (SBS), Polystyrene-polyisoprene-polystyrene (SIS) ), Poly (α-methylstyrene) -polybutadiene-poly (αmethylstyrene) (α-MeSBα-MeS), poly (αmethylstyrene) -polyisoprene-poly (α-methylstyrene), ethylene-propylene copolymer (EP), butadiene-styrene copolymer (EP), ethylene-propylene-ethylidene copolymer, ethylene-propylene-diene copolymer, ethylene-propylene copolymer rubber, ethylene-butene-1 copolymer rubber, Ethylene-propylene Ethyldenene norbornene copolymer rubber, ethylene-propylene-dicyclopentadiene copolymer rubber, ethylene-propylene-1,4 hexadiene copolymer rubber, ethylene-butene-1-ethylidenenorbornene copolymer rubber, ethylene-butene- 1-dicyclopentadiene copolymer rubber, ethylene-butene-1-1,4 hexadiene copolymer rubber, acrylonitrile-chloroprene rubber (NCR), styrene-chloroprene rubber (SCR), styrene-butadiene-styrene (SBS) Styrenic thermoplastic elastomers such as polymers, styrene-isoprene-styrene (SIS) copolymers, styrene-hydrogenated polyolefin-styrene (SEBS) copolymers, butadiene-styrene block copolymers, styrene-rubber intermediate blocks -Su There are synthetic rubbers such as block copolymers such as a tylene copolymer and natural rubbers. The rubber and / or elastomer preferably has a softening point of 150 ° C. or less, may contain a carboxyl group, and may be used in combination of two or more.

  As the elastomer, it is desirable to select a styrene thermoplastic elastomer. Examples of the styrene-based thermoplastic elastomer include styrene-butadiene rubber, styrene-isoprene rubber, styrene-chloroprene rubber, styrene-butadiene-styrene (SBS) copolymer, styrene-isoprene-styrene (SIS) copolymer, Examples include styrene-hydrogenated polyolefin-styrene (SEBS) copolymers. Since the styrene elastomer has a styrene polymer chain as a hard segment and a diene polymer chain or a hydrogenated product as a soft segment, the recycled thermoplastic resin is a styrene polymer. Whether it is a resin or an olefin resin, it is compatible, and in the case of a mixture of a styrene resin and an olefin resin, it functions as a compatibilizer for both.

Furthermore, in the present invention, the thermoplastic resin includes calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, calcium sulfite, calcium phosphate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, magnesium oxide, titanium oxide, iron oxide. , Zinc oxide, alumina, silica, diatomaceous earth, dolomite, gypsum, talc, clay, asbestos, mica, glass fiber, carbon fiber, calcium silicate, bennite, white carbon, carbon black, iron powder, aluminum powder, stone powder, Inorganic fillers such as blast furnace slag, fly ash, cement, zirconia powder, natural fibers such as cotton, hemp, bamboo fiber, palm fiber, wool, silk, polyamide fiber, polyester fiber, acrylic fiber, viscose fiber, acetate fiber, Vinyl chloride fiber, vinyl chloride Organic fibers such as copper fiber, vinylon fiber, acetate fiber, asbestos fiber, glass fiber, carbon fiber, ceramic fiber, metal fiber, whisker and other inorganic fibers, linter, linen, sisal, wood powder, palm powder, walnut powder, Reinforcing materials such as starch, wheat flour, wood chips, wood flour, and organic fillers such as incineration ash of sludge generated by wastewater treatment may be added to improve shape retention, dimensional stability, compression and tensile strength, etc. . Other pigments and dyes, plasticizers such as DOP and DBP, antioxidants, antistatic agents, crystallization accelerators, flame retardants, flameproofing agents, insecticides, preservatives, waxes, lubricants, antiaging agents, UV absorption An agent or the like may be added. These components may be added singly or in combination of two or more.
Examples of flame retardants include phosphorus flame retardants, nitrogen flame retardants, sulfur flame retardants, boron flame retardants, bromine flame retardants, guanidine flame retardants, phosphate flame retardants, phosphate ester flame retardants, and amino resins. There are flame retardants

[Extrusion molding equipment]
As shown in FIG. 1, the extrusion molding apparatus used in the extrusion molding method of the present invention comprises an extruder 10, a die 11, a sizing device 12, and a drawing roll 13 in order from the upstream side. Yes.
The extruder 10 has a hopper 21 and a cylinder 22. The hopper 21 is filled with pellets made of the thermoplastic resin, and is connected to the base end of the cylinder 22 so as to feed the pellets into the cylinder 22. Yes. The cylinder 22 heats and melts the thermoplastic resin fed as a pellet and extrudes it from its tip. The cylinder 22 accommodates a screw 23 that melts the pellet and measures the amount supplied to the die 11. Yes.
The die 11 is for molding a thermoplastic resin in a heated and melted state extruded from the tip of the cylinder 22 of the extruder 10 into a predetermined shape, and is connected to the tip of the cylinder 22. A die having a slit having a shape corresponding to a desired molding shape is used as the die 11, and the thermoplastic resin in a heat-melted state is formed into a heat-softened molded product having a predetermined shape by passing through the slit. . For example, in FIG. 1, a T-die having a long rectangular slit is drawn as the die 11, and when the T-die is used, a plate-like molded body is formed. For example, when a die having a circular or polygonal slit is used as the die 11, a molded body having a tubular shape is formed.

The sizing device 12 is for cooling and solidifying the heat-softened molded product extruded from the die 11, and an introduction path (not shown) through which the molded product is introduced inside the cooling platen 31. )have. The peripheral surface of the introduction path is a cooling surface, and a plurality of flow paths 32 through which the refrigerant flows are formed in the cooling plate 31 at positions near the cooling surface.
In each of the plurality of flow paths 32, one end of each of the plurality of supply branch pipes 33 </ b> A extending from the refrigerant branch port of the branch body 33 is connected to each end serving as the refrigerant inlet. The branch body 33 is provided with a refrigerant introduction port, and a refrigerant cooling device 35 such as a compressor is connected to the refrigerant introduction port via a refrigerant supply path 34. A refrigerant recovery path 36 extends from the refrigerant cooling device 35, and a recovery body 37 is connected to the refrigerant recovery path 36. A plurality of recovery branch pipes 37 </ b> A extend from the recovery body 37, and each recovery branch pipe 37 </ b> A is connected to each other end serving as a refrigerant outlet in the plurality of flow paths 32.
The refrigerant cooling device 35 is for holding the refrigerant at a predetermined temperature. The refrigerant is sent from the refrigerant supply path 34 to the branch body 33, branched into the plurality of supply branch pipes 33 </ b> A by the branch body 33, and sent from the supply branch pipes 33 </ b> A to the plurality of flow paths 32, respectively. Further, the refrigerant flowing through the flow path 32 is sent from each recovery branch pipe 37A to the recovery body 37 and gathers, and is recovered from the recovery body 37 via the refrigerant recovery path 36 to the refrigerant cooling device 35. After being set to a predetermined temperature by the cooling device 35, it is sent out from the refrigerant supply path 34 toward the flow path 32 of the cooling panel 31.

The sizing device 12 has a plurality of (three in the present embodiment) cooling boards 31, and the cooling board 31 at a position closest to the die 11 among the plurality of cooling boards 31 is formed of a first introduction path. The primary cooling unit C1 is configured. Moreover, the secondary cooling part C2 which consists of a 2nd introduction path is comprised except the thing which comprises the primary cooling part C1 among the some cooling boards 31. FIG. In the primary cooling section C1, chiller water (distilled water) is sent as a refrigerant, and in the secondary cooling section C2, an antifreeze liquid is sent as a refrigerant.
In the branch body 33, the refrigerant supply path 34 has a larger pipe diameter than the supply branch pipe 33A. Further, the diameter of the refrigerant introduction port to which the refrigerant supply path 34 is connected is made larger than the diameter of the refrigerant branch port to which the supply branch pipe 33A is connected. That is, as described above, in the sizing device 12 of the present invention, the antifreeze liquid is used as the refrigerant of the secondary cooling unit C2. Since the antifreeze liquid has a higher viscosity than the chiller water, it is likely to be clogged in the flow path 32. Therefore, by making the diameter of the refrigerant inlet larger than the diameter of the refrigerant branch port, the pressure of the refrigerant sent to the flow path 32 is increased, and clogging of the refrigerant in the flow path 32 is suppressed.

[Extrusion method]
When extrusion molding is performed using the above extrusion molding apparatus, first, pellets made of thermoplastic resin are put into the hopper 21 of the extruder 10 to be heated and melted in the cylinder 22. The heated melt is press-fitted into the die 11 from the tip of the cylinder 22 by the rotation of the screw 23, and is formed into a predetermined shape when pushed out from the slit of the die 11 to become a heat-softened molded product.
In the extrusion molding method of the present invention, a thermoplastic resin having a thermal conductivity of 0.2 W / m · K or less is used. When a thermoplastic resin having a thermal conductivity exceeding 0.2 W / m · K is used, molding defects such as sink marks and cracks due to rapid cooling occur in the obtained molded product. Although rarely, even if a thermoplastic resin having a thermal conductivity exceeding 0.2 W / m · K is used in the extrusion molding method of the present invention, molding defects may not occur. Compared with the conventional extrusion molding method in which cooling is performed using only the cooling method, there is no great difference in the cooling rate, and the unique effect of the present invention of increasing the molding rate cannot be obtained.

  Immediately after being extruded from the die 11, the heat-softened molded product is introduced into the primary cooling part C1 of the sizing device 12, and the surface thereof contacts the primary cooling surface of the cooling plate 31 in the first introduction path. The primary cooling is performed while restricting to a predetermined dimension. In the primary cooling unit C1, chiller water is used as a refrigerant, and the chiller water is maintained at a temperature of 10 to 12 ° C. by the refrigerant cooling device 35. When the temperature of the chiller water that is the refrigerant is less than 10 ° C., the chiller water freezes and the refrigerant cannot flow. When the temperature of the chiller water that is the refrigerant exceeds 12 ° C., the difference in cooling temperature between the primary cooling part C1 and the secondary cooling part C2 increases, resulting in deterioration of dimensional accuracy due to residual strain and occurrence of molding defects. Etc. will occur. Also, the molding speed cannot be increased.

  The molded object in an unsolidified state after the primary cooling in the primary cooling unit C1 is introduced into the secondary cooling unit C2 of the sizing device 12, and the surface thereof is the secondary cooling surface of the cooling plate 31 in the second introduction path. By being in contact with the water, it is secondarily cooled and solidified by cooling. In the secondary cooling unit C2, an antifreeze mainly composed of ethylene glycol, for example, is used as a refrigerant, and the antifreeze is maintained at a temperature of −10 to 10 ° C. by the refrigerant cooling device 35. When the temperature of the antifreeze that is a refrigerant is less than −10 ° C., the molded product cannot contact the secondary cooling surface due to excessive thermal shrinkage of the molded product due to rapid cooling. Molding defects such as cracks will occur. When the temperature of the antifreeze liquid as the refrigerant exceeds 10 ° C., the internal heat generated by the heat-softened molded product cannot be suitably removed, and the unique effect of the present invention that increases the molding speed cannot be obtained.

  The molded product cooled and solidified by the secondary cooling unit C2 of the sizing device 12 is pulled out from the second introduction path by being pulled by the drawing roll 13, and collected outside the device. At this time, the pulling speed by the drawing roll 13 is preferably higher than 2.0 m / min and not higher than 3.0 m / min. When the tensile speed is 2.0 m / min or less, the molded product excessively shrinks due to rapid cooling due to a long contact time with the cooling surface per unit area on the surface of the molded product. There is a possibility that the molded product cannot contact the secondary cooling surface at C2 and is insufficiently cooled. When the tensile speed exceeds 3.0 m / min, the internal heat of the molded product cannot be sufficiently removed, and the molded product is pulled while the inside is soft, so that it is cut off or extended in the middle. Or the like, the dimensional accuracy may be deteriorated. Alternatively, when the tensile speed exceeds 3.0 m / min, there is a possibility that the molded product can be molded satisfactorily. Compared to the molding speed due to, the cutting may not be in time.

  From the viewpoint of improving the molding speed, it is desirable that the extruded product molded by the above extrusion molding method has a thickness of 3 mm or less. If the wall thickness exceeds 3 mm, internal heat cannot be sufficiently dissipated and cooling may be insufficient. Although it is possible to eliminate the shortage of cooling by elongating the sizing device 12, the molding speed cannot be improved in this case. In addition, moldings made of resin are more prone to molding defects such as sink marks due to thermal shrinkage as the wall thickness increases, and those having a thick wall are excellent in rigidity but difficult to process. Is preferably 3 mm or less.

The extrusion method including primary cooling using chiller water and secondary cooling using antifreeze as described above is particularly desirable when the thermoplastic resin to be used is a crystalline resin.
In other words, a crystalline resin has a structure in which a strongly bonded part (crystal structure) in which molecules are regularly arranged and an amorphous part (amorphous structure) in which molecules are irregularly arranged are connected. have. When the crystalline resin is rapidly cooled by a method such as direct cooling, the crystalline structure is not formed, so that it is considered that the molded body is not formed.
When the crystalline resin as described above is cooled by primary cooling using chiller water and secondary cooling using antifreeze, the surface of the molded body is first solidified in the primary cooling stage. It is considered that the orientation of the molecules is adjusted to form a crystal structure, and the formation of the crystal structure is further propagated into the molded body. In other words, solidification of the entire molded body has already begun by primary cooling, and in secondary cooling, excess heat (internal heat) generated from the inside of the molded body due to the formation of the crystal structure is mainly performed. It is thought that. Therefore, for molded bodies made of crystalline resin, we consider that the molding speed can be improved by completing the dissipation of internal heat quickly, and the primary cooling uses chiller water, which is the same or slightly lower temperature than the conventional method. Cooling is used as a starting point for the formation of a crystal structure, and in secondary cooling, the internal heat is dissipated in a short time by cooling at a temperature clearly lower than that of the conventional method using an antifreeze.

On the other hand, when the thermoplastic resin used is a non-crystalline resin, the non-crystalline resin has a structure consisting only of a structure in which molecules are randomly arranged, and for a molded product obtained from the non-crystalline resin, It is not necessary to form a crystal structure like a crystalline resin. Therefore, it is considered that the molding speed of a molded body made of an amorphous resin can be improved by completing the dissipation of internal heat as quickly as possible. Therefore, in the extrusion molding method using an amorphous resin, cooling using chiller water may be omitted, and all cooling may be performed using only antifreeze.
Furthermore, in the extrusion molding method of the present invention, for the cooling using the antifreeze liquid regardless of the crystalline resin or the amorphous resin, for example, the cooling is performed using the antifreeze liquid at 0 to 10 ° C. in the first stage, and the second stage. The cooling may be performed in a plurality of stages at different temperatures, such as by using an antifreeze solution of −10 to 0 ° C.

Examples that further embody the present invention will be described below.
[Molding condition]
As the extruder 10, an 80 mm full flight screw (32 L / D 48 hp) manufactured by IKG was used. The extruder 10 was used to form a shutter-type bath lid by two-color molding.
[Example 1]
PP having a thermal conductivity of 0.2 W / m · K or less (0.13 W / m · K) and a styrene elastomer were used as materials. When primary cooling with chiller water set at 10 ° C. and secondary cooling with antifreeze set at −5 ° C. was performed and the molding was carried out at a tensile speed of 2.6 m / min, 245 g (length: 70 cm) was formed in quadruplicate. The time required for molding the molded product was 17 seconds.
Furthermore, it was possible to mold at a tensile speed of 3.2 m / min, and the molding time at this time was 13 seconds.
[Comparative Example 1]
When the same material as in Example 1 above was used and only cooling with chiller water set at 10 ° C. was performed and the molding was performed at a tensile speed of 2.6 m / min, the molded product was stretched and cut off in the middle. I could not. At this time, although the surface of the molded product was hard enough to be touched by the hand, the reason why the molded product was stretched in the middle was because the internal heat of the molded product was not sufficiently removed. I thought.
[Comparative Example 2]
Using the same material as in Example 1 above, only cooling with chiller water set at 10 ° C. was performed, and the tensile speed was slowed down until a good molded product was obtained. The tensile speed at which the molded product of No. 1 can be molded was 2.0 m / min, and the time required for molding was 25 seconds. This is about 30% slower in molding speed than 17 seconds in Example 1.

[Example 2]
PP having a thermal conductivity of 0.2 W / m · K or less (0.13 W / m · K) was used as the material. Primary cooling with chiller water set at 10 ° C and secondary cooling with antifreeze set at -5 ° C, forming a plate-like body with a tensile speed of 2.3 m / min, a wall thickness of 3 mm and a width of 275 mm did. The time required for forming a molded article having a length of 70 cm was about 18 seconds. As a result of visual observation of the surface state of the molded product made of a plate-like body, there was no molding defect such as sink marks and the like, and the plate thickness was substantially uniform and was good.

[Example 3]
A plate-like body was formed in the same manner as in Example 2 except that the temperature of the chiller water was 12 ° C. by primary cooling. The time required for molding a molded article having a length of 70 cm is about 18 seconds. As a result of visual observation of the surface state of the molded article made of a plate-like body, there is no molding defect such as sink marks, and the plate thickness is also substantially the same. It was uniform and good.
[Comparative Example 3]
A plate-like body was formed in the same manner as in Example 2 except that the temperature of chiller water was 8 ° C. by primary cooling. During the molding, the chiller water was frozen and could not be circulated.
[Comparative Example 4]
A plate-like body was formed in the same manner as in Example 2 except that the temperature of chiller water was 13 ° C. by primary cooling. The time required for molding a molded article having a length of 70 cm was about 18 seconds, and the molded article made of a plate-like body did not show molding defects such as sink marks as a result of visual observation of the surface state. Became non-uniform.

[Example 4]
A plate-like body was formed in the same manner as in Example 2 except that the temperature of the antifreeze solution was −10 ° C. by secondary cooling. The time required for molding a molded product having a length of 70 cm is about 18 seconds. As a result of visual observation of the surface state of the molded product made of a plate-like body, there is no molding defect such as sink marks, and the plate thickness is also substantially the same. It was uniform and good.
[Example 5]
A plate-like body was formed in the same manner as in Example 2 except that the temperature of the antifreeze liquid was 10 ° C. by secondary cooling. The time required for molding a molded product having a length of 70 cm is about 18 seconds. As a result of visual observation of the surface state of the molded product made of a plate-like body, there is no molding defect such as sink marks, and the plate thickness is also substantially the same. It was uniform and good.
[Comparative Example 5]
A plate-like body was formed in the same manner as in Example 2 except that the temperature of the antifreeze liquid was −11 ° C. by secondary cooling. The time required for molding a molded article having a length of 70 cm was 14 seconds, and as a result of visual observation of the surface state of the molded article made of a plate-like body, sink marks were generated and molding defects were generated.
[Comparative Example 6]
A plate-like body was formed in the same manner as in Example 2 except that the temperature of the antifreeze liquid was 11 ° C. by secondary cooling. The time required for molding a molded article having a length of 70 cm was about 18 seconds, and the molded article made of a plate-like body had no molding defects such as sink marks as a result of visual observation of the surface state. Became non-uniform.

[Comparative Example 7]
A plate-like body having a length of 70 cm was formed in the same manner as in Example 2 except that polyethylene (PE) having a thermal conductivity exceeding 0.2 W / m · K (0.41 W / m · K) was used as a material. . The time required for molding the molded product was about 18 seconds per sheet. When ten plate-like bodies were molded, some sink marks were generated in one sheet. Nine sheets were good.
[Comparative Example 8]
Polyethylene (PE) with a thermal conductivity exceeding 0.2 W / m · K (0.41 W / m · K) was used as a material, and primary cooling and secondary cooling were performed using chiller water set at 10 ° C. A plate-like body having a length of 70 cm was formed in the same manner as in Example 2 except for the above. The time required for molding the molded product was about 18 seconds per sheet. When ten plate-like bodies were molded, all were free from molding defects such as sink marks and the like, and the plate thickness was substantially uniform, which was good.
From the results of Comparative Example 7 and Comparative Example 8, it was found that PE having a thermal conductivity exceeding 0.2 W / m · K hardly exhibits the effect of increasing the molding speed by using an antifreeze liquid as a refrigerant.

[Reference Example 1]
A plate-like body having a length of 70 cm was formed in the same manner as in Example 2 except that primary cooling and secondary cooling were performed using an antifreeze liquid set to −5 ° C. The time required for molding the molded product was about 18 seconds per sheet. When ten plate-like bodies were molded, one piece had some sink marks and the plate thickness was not uniform. Nine sheets were good.
From the result of Reference Example 1, it was shown that PP, which is a crystalline resin, is desirably cooled by primary cooling using chiller water and secondary cooling using antifreeze.
[Example 6]
A plate-like body having a length of 70 cm was formed in the same manner as in Example 2 except that the tensile speed was set to 3.0 m / min. The time required for molding the molded product was about 14 seconds per sheet. When ten plate-like bodies were molded, all were free of molding defects and the plate thickness was substantially uniform and good.
[Reference Example 2]
A plate-like body having a length of 70 cm was molded in the same manner as in Example 2 except that the tensile speed was 3.1 m / min. When trying to mold 10 plate-like bodies, the molded product was cut in the middle of the 8th sheet. The time required for molding up to the seventh sheet was about 14 seconds per sheet. When seven plate-like bodies were molded, there were no molding defects up to the first to sixth sheets, and the plate thickness was substantially uniform and good. The plate thickness was thin.
[Reference Example 3]
A plate-like body having a length of 70 cm was formed in the same manner as in Example 2 except that the tensile speed was 2.0 m / min. When ten plate-like bodies were molded, all were free of molding defects and the plate thickness was substantially uniform and good. The time required for molding the molded product was about 25 seconds per sheet, which was not significantly different from the conventional molding speed (about 25 seconds per sheet).
[Reference Example 4]
A plate-like body having a length of 70 cm was formed in the same manner as in Example 2 except that the wall thickness was 3.1 mm. The time required for molding the molded product was about 18 seconds per sheet. When ten plate-like bodies were molded, sink marks were generated in two sheets, and the plate thickness was uneven in one sheet. The remaining seven sheets had no molding defects, and the plate thickness was substantially uniform and good.

[Example 7]
PMMA having a thermal conductivity of 0.2 W / m · K or less (0.19 W / m · K) was used as the material. A transparent plate having a thickness of 3 mm and a width of 275 mm with primary cooling with chiller water set at 10 ° C. and secondary cooling with antifreeze set at −5 ° C., with a tensile speed of 2.6 m / min. Was molded. The time required for forming a molded article having a length of 70 cm was about 14 seconds. As a result of visual observation of the surface state of the molded product made of a plate-like body, there was no molding defect such as sink marks and the like, and the plate thickness was substantially uniform and was good.
[Example 8]
A plate-like body having a length of 70 cm was formed in the same manner as in Example 7 except that primary cooling with an antifreeze liquid set at 0 ° C. and secondary cooling with an antifreeze liquid set at −5 ° C. were performed. The time required for molding the molded product was about 14 seconds. As a result of visual observation of the surface state of the molded product made of a plate-like body, there was no molding defect such as sink marks and the like, and the plate thickness was substantially uniform and was good.
[Example 9]
PC having a thermal conductivity of 0.2 W / m · K or less (0.19 W / m · K) was used as the material. A transparent plate having a thickness of 3 mm and a width of 275 mm with primary cooling with chiller water set at 10 ° C. and secondary cooling with antifreeze set at −5 ° C., with a tensile speed of 2.6 m / min. Was molded. The time required for forming a molded article having a length of 70 cm was about 14 seconds. As a result of visual observation of the surface state of the molded product made of a plate-like body, there was no molding defect such as sink marks and the like, and the plate thickness was substantially uniform and was good.
[Comparative Example 9]
A plate-like body having a length of 70 cm was formed in the same manner as in Example 9 except that polyethylene terephthalate (PET) having a thermal conductivity exceeding 0.2 W / m · K (0.30 W / m · K) was used as a material. did. The time required for molding the molded product was about 14 seconds per sheet. When ten plate-like bodies were molded, some sink marks were generated in the three sheets. The remaining seven sheets were good.
Furthermore, a plate-like body having a length of 70 cm was molded in the same manner as in Example 2 except that the PET was used as a material and primary cooling and secondary cooling were performed using chiller water set at 10 ° C. The time required for molding the molded product was about 14 seconds per sheet. When ten plate-like bodies were molded, all were free from molding defects such as sink marks and the like, and the plate thickness was substantially uniform, which was good.

  In the present invention, a non-foamed molded product made of a thermoplastic resin can be produced in a short time. Such a non-foamed molded product is extremely useful as a material for various industrial products such as building materials, and can be used industrially. It is.

DESCRIPTION OF SYMBOLS 10 Extruder 11 Die 12 Sizing device 13 Pull-out roll 31 Cooling board C1 Primary cooling part C2 Secondary cooling part

Claims (4)

It is an extrusion molding method for molding a non-foamed molded article using a thermoplastic resin having a thermal conductivity of 0.2 W / m · K or less as a material,
After extruding the heated melt of the thermoplastic resin from the extruder and the die,
Introducing the extruded heat-softened molded article into an introduction path of a sizing device through which an antifreeze liquid maintained at a temperature of −10 to 10 ° C. is sent as a refrigerant;
With the peripheral surface of the introduction path as a cooling surface, the molded product in a heat-softened state is brought into contact with the cooling surface to be cooled and solidified while being regulated to a predetermined size,
A method for extruding a non-foamed molded product, wherein the molded product cooled and solidified in this manner is pulled out of the sizing device by being pulled by a drawing roll. It is an extrusion molding method for molding a non-foamed molded article using a thermoplastic resin having a thermal conductivity of 0.2 W / m · K or less as a material,
Immediately after extruding the heated melt of the thermoplastic resin from the extruder and die,
Introducing the extruded heat-softened molded product into a first introduction path of a sizing device in which chiller water maintained at a temperature of 10 to 12 ° C. is passed as a refrigerant;
Using the peripheral surface of the first introduction path as a primary cooling surface, the primary cooling surface is subjected to primary cooling while being brought into contact with the molded product in a heat-softened state and regulated to a predetermined size,
After the primary cooling, the unsolidified molded product is introduced into the second introduction path of the sizing device in which the antifreeze liquid maintained at a temperature of −10 to 10 ° C. is passed as a refrigerant,
With the peripheral surface of the second introduction path as a secondary cooling surface, the molded product in an unsolidified state is brought into contact with the secondary cooling surface to be cooled and solidified,
A method for extruding a non-foamed molded product, wherein the molded product cooled and solidified in this manner is pulled out of the second introduction path by being pulled by a drawing roll. The method for extruding a non-foamed molded article according to claim 1 or 2, wherein the thermoplastic resin is at least one of polypropylene (PP), acrylic resin (PMMA), and polycarbonate (PC). 4. The molded product according to claim 1, wherein the molded product has a thickness of 3 mm or less, and the molded product is pulled by a drawing roll at a speed of 2.0 m / min or more and 3.0 m / min or less. 5. A method for extruding the non-foamed molded article.