JP2012121271A - Method of manufacturing laminated extruded resin plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a laminated extruded resin plate having excellent appearance, free from the occurrence of tack mark and having suppressed warpage deformation.SOLUTION: A method of manufacturing an extruded resin plate is for obtaining the laminated extruded resin plate 6 by melting and kneading two or more kinds of thermoplastic resins in which the thermal deformation temperature difference between a resin having the highest thermal deformation temperature and a resin having the lowest thermal deformation temperature is 10°C or more by extruders 1, 2 for coextrusion molding from a die 3 and cooling with at least three cooling rolls 51, 52, 53. The molten resin is put in a gap between a final cooling roll 53 and a cooling roll 52 just before the final cooling roll 53 so that a layer comprising a resin except the resin having the highest thermal deformation temperature may be brought into contact with the final cooling roll and pressed and formed between the cooling rolls to obtain the laminated extruded resin plate 6. At least one surface of the laminated extruded resin plate 6 is heated by a heater 7 at a temperature equal to or above the highest thermal deformation temperature in the thermal deformation temperature of two or more kinds of the thermoplastic resins constituting the laminated extruded resin plate 6.

Description

  The present invention relates to a method for producing a laminated extruded resin plate, and more particularly to a method for producing a laminated extruded resin plate that has a good appearance, does not generate a peeling mark (tack mark), and further suppresses warping deformation.

  Extruded resin plates made of thermoplastic resins are used in a wide range of lighting covers, signboards, building materials, touch panel substrates, liquid crystal display front plates, light guide plates, and the like. In general, when an extruded resin plate made of a thermoplastic resin is manufactured, a molten resin extruded from a die is wound around two or more cooling rolls, sandwiched between these rolls, and formed into a plate shape while being cooled. When molded in this way, an extruded resin plate having a good appearance can be obtained. However, when it is sandwiched between cooling rolls and cooled and molded, the resulting extruded resin plate may be warped and deformed.

  In order to prevent warping deformation of a single-layer extruded resin plate, for example, Patent Documents 1 and 2 disclose a method of heating both surfaces of a single-layer extruded resin plate with a heater after peeling from the final roll. Is disclosed.

  In a multilayer extruded resin plate (laminated extruded resin plate), the temperature of the final cooling roll may be set high in order to suppress warpage deformation. However, when a layer made of a resin having a low heat distortion temperature (Th) comes into contact with the final cooling roll, the resin is not easily peeled off from the cooling roll, and the width direction due to an impact at the time of roll peeling called a peeling mark (tack mark) There is a problem that this line is likely to occur.

  Therefore, there is a demand for a method for producing a laminated extruded resin plate that has a good appearance, does not generate tack marks, and further suppresses warpage deformation.

Japanese Patent Laid-Open No. 7-9538 JP-A-6-246828

  An object of the present invention is to provide a method for producing a laminated extruded resin plate that has a good appearance, does not generate tack marks, and further suppresses warping deformation.

As a result of intensive studies to solve the above-described problems, the present inventors have found a solution means having the following configuration and have completed the present invention.
(1) A resin having the highest heat deformation temperature and a resin having the lowest heat deformation temperature are melt-kneaded with two or more thermoplastic resins having a difference in heat deformation temperature of 10 ° C. or more by an extruder, respectively, A method for producing a laminated extruded resin plate obtained by co-extrusion molding and cooling with at least three cooling rolls to obtain a laminated extruded resin plate,
Between the cooling rolls, the molten resin is sandwiched between the final cooling roll and the cooling roll immediately before the final cooling roll so that the layer made of the resin other than the resin having the highest thermal deformation temperature is in contact with the final cooling roll. To obtain a laminated extruded resin plate by pressure bonding with
Heating at least one of both surfaces of the laminated extruded resin plate at a temperature equal to or higher than the highest thermal deformation temperature of the two or more thermoplastic resins constituting the laminated extruded resin plate by a heater A method for producing a laminated extruded resin plate.
(2) The manufacturing method according to (1), wherein a non-contact surface of the laminated extruded resin plate with a final cooling roll is heated.
(3) Heating by the heater is performed in the range of MaxTh to (MaxTh + 50 ° C.) when MaxTh is the heat distortion temperature of the thermoplastic resin constituting the laminated extruded resin plate (1). ) Or (2).

  According to the present invention, it is a laminated extruded resin plate using two or more kinds of thermoplastic resins having a difference in heat deformation temperature of 10 ° C. or more, has a good appearance, does not generate a tack mark, and is further warped and deformed. There is an effect that a suppressed laminated extruded resin plate can be obtained.

It is a schematic explanatory drawing which shows the manufacturing method of the laminated extrusion resin board which concerns on one embodiment of this invention. In FIG. 1, it is an enlarged view of the part enclosed with the broken line.

  The method for producing a laminated extruded resin plate according to the present invention includes melt-kneading two or more thermoplastic resins with an extruder, co-extrusion molding from a die, and cooling with at least three cooling rolls. Including a step of obtaining a plate (extrusion molding step).

  In the extrusion process, two or more types of thermoplastic resins are first melt-kneaded in an extruder. The thermoplastic resin is not particularly limited as long as it is a melt processable resin. For example, polyvinyl chloride resin, acrylonitrile-butadiene-styrene resin, low density polyethylene resin, high density polyethylene resin, linear low density polyethylene resin, Polystyrene resin, polypropylene resin, acrylonitrile-styrene resin, cellulose acetate resin, ethylene-vinyl acetate resin, acrylic resin, acrylic-acrylonitrile-styrene resin, acrylic-chlorinated polyethylene resin, ethylene-vinyl alcohol resin, fluorine resin, methacrylic resin, Polyacetal resin, polyamide resin, polyethylene terephthalate resin, polycarbonate resin, polysulfone resin, polyethersulfone resin, methylpentene resin, polyarylate resin, polyester In addition to general-purpose or engineering plastics such as butylene terephthalate resins, resins containing alicyclic structure-containing ethylenically unsaturated monomer units, polyphenylene sulfide resins, polyphenylene oxide resins, polyether ether ketone resins, polyvinyl chloride elastomers, Examples include chlorinated polyethylene, ethylene-ethyl acrylate resins, thermoplastic polyurethane elastomers, thermoplastic polyester elastomers, ionomer resins, styrene / butadiene block polymers, ethylene-propylene rubbers, polybutadiene resins, and acrylic rubbers. .

  In the method for producing a laminated extruded resin plate according to the present invention, among these thermoplastic resins, the resin having the highest thermal deformation temperature and the resin having the lowest thermal deformation temperature are 10 ° C. or higher, preferably 10 ° C. to Two or more thermoplastic resins having a difference in heat distortion temperature of 60 ° C., more preferably 15 ° C. to 50 ° C. are used. The heat distortion temperature (Th) of the thermoplastic resin is a temperature measured according to ASTM D-648. The combinations of such thermoplastic resins include polycarbonate resin and methacrylic resin, polycarbonate resin and acrylic resin, acrylic resin and acrylic resin with improved heat resistance (heat resistant acrylic resin), polycarbonate resin and heat resistant acrylic resin, methyl methacrylate Examples thereof include a styrene copolymer resin and a polycarbonate resin, and a combination of a methyl methacrylate-styrene copolymer resin and a heat-resistant acrylic resin. A heat-resistant acrylic resin is a resin obtained by copolymerizing maleic acid or an imide compound with methyl methacrylate.

  Polycarbonate resins include those obtained by reacting a dihydric phenol and a carbonate precursor by an interfacial polycondensation method or a melt transesterification method, as well as those obtained by polymerizing a carbonate prepolymer by a solid phase transesterification method, or cyclic carbonates. Examples thereof include those obtained by polymerizing a compound by a ring-opening polymerization method.

  Examples of the dihydric phenol include hydroquinone, resorcinol, 4,4′-dihydroxydiphenyl, bis (4-hydroxyphenyl) methane, bis {(4-hydroxy-3,5-dimethyl) phenyl} methane, 1,1-bis. (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A), 2,2-bis {( 4-hydroxy-3-methyl) phenyl} propane, 2,2-bis {(4-hydroxy-3,5-dimethyl) phenyl} propane, 2,2-bis {(4-hydroxy-3,5-dibromo) Phenyl} propane, 2,2-bis {(3-isopropyl-4-hydroxy) phenyl} propane, 2,2-bis {(4- Droxy-3-phenyl) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl) -3,3-dimethylbutane, 2,4-bis (4-hydroxyphenyl) -2-methylbutane, 2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) -4 -Methylpentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3 5-trimethylcyclohexane, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis {(4-hydroxy- -Methyl) phenyl} fluorene, α, α'-bis (4-hydroxyphenyl) -o-diisopropylbenzene, α, α'-bis (4-hydroxyphenyl) -m-diisopropylbenzene, α, α'-bis ( 4-hydroxyphenyl) -p-diisopropylbenzene, 1,3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane, 4,4′-dihydroxydiphenylsulfone, 4,4′-dihydroxydiphenylsulfoxide, 4, Examples include 4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxydiphenyl ketone, 4,4′-dihydroxydiphenyl ether, and 4,4′-dihydroxydiphenyl ester. These may be used alone or in combination of two or more. May be.

  Among them, bisphenol A, 2,2-bis {(4-hydroxy-3-methyl) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) -3- Methylbutane, 2,2-bis (4-hydroxyphenyl) -3,3-dimethylbutane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-hydroxyphenyl)- A homopolymer or copolymer obtained from at least one bisphenol selected from the group consisting of 3,3,5-trimethylcyclohexane and α, α′-bis (4-hydroxyphenyl) -m-diisopropylbenzene is preferred. In particular, homopolymers of bisphenol A, and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethyl At least one selected from rucyclohexane and bisphenol A, 2,2-bis {(4-hydroxy-3-methyl) phenyl} propane, and α, α'-bis (4-hydroxyphenyl) -m-diisopropylbenzene A copolymer with a dihydric phenol is preferred.

  As the carbonate precursor, for example, carbonyl halide, carbonate ester or haloformate is used, and specific examples include phosgene, diphenyl carbonate, dihaloformate of dihydric phenol, and the like.

  A methacrylic resin or an acrylic resin (hereinafter sometimes referred to as a (meth) acrylic resin) is a polymer containing 50% by weight or more of methyl methacrylate or methyl acrylate units as monomer units. The content of methyl methacrylate or methyl acrylate units is preferably 70% by weight or more, and may be 100% by weight. A polymer having 100% by weight of methyl methacrylate unit is a methyl methacrylate homopolymer obtained by polymerizing methyl methacrylate alone, and a polymer having 100% by weight of methyl acrylate unit is methyl acrylate. It is a methyl acrylate homopolymer obtained by polymerizing alone.

  The (meth) acrylic resin may be a copolymer of methyl methacrylate or methyl acrylate and another monomer that can be copolymerized with the methyl methacrylate or methyl acrylate.

  Examples of other monomers that can be copolymerized with methyl methacrylate include methacrylic acid esters other than methyl methacrylate. Examples of such methacrylic acid esters include ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, and the like. Also, acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, methacrylic acid, acrylic acid Unsaturated acids such as, halogenated styrenes such as chlorostyrene and bromostyrene, substituted styrenes such as vinyltoluene and alkyl styrenes such as α-methylstyrene, acrylonitrile, methacrylonitrile, maleic anhydride, phenylmaleimide, cyclohexyl Examples include maleimide. Such monomers may be used alone or in combination of two or more.

  Examples of other monomers that can be copolymerized with methyl acrylate include acrylic esters other than methyl acrylate. Examples of such acrylates include ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and the like. Also, methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, methacrylic acid, acrylic acid Unsaturated acids such as, halogenated styrenes such as chlorostyrene and bromostyrene, substituted styrenes such as vinyltoluene and alkyl styrenes such as α-methylstyrene, acrylonitrile, methacrylonitrile, maleic anhydride, phenylmaleimide, cyclohexyl Examples include maleimide. Such monomers may be used alone or in combination of two or more.

  The (meth) acrylic resin may be a resin composition by adding a rubbery polymer. Thereby, since it becomes difficult to crack at the time of shaping | molding, a yield can be improved. Examples of the rubber-like polymer include an acrylic multilayer polymer, and a graft copolymer obtained by graft-polymerizing an ethylenically unsaturated monomer in a proportion of 95 to 20 parts by weight to 5 to 80 parts by weight of a rubber-like polymer. Etc.

  Examples of the acrylic multilayer structure polymer include those having a rubber elastic layer or an elastomer layer in an amount of 20 to 60 parts by weight and having a hard layer at the outermost layer, and further having a hard layer as the innermost layer. You may do it.

  The rubber elastic layer or the elastomer layer is a layer of an acrylic polymer having a glass transition point (Tg) of less than 25 ° C., for example, lower alkyl acrylate and methacrylate, lower alkoxy acrylate, cyanoethyl acrylate, acrylamide, and hydroxy lower alkyl acrylate. And a polymer obtained by crosslinking one or more monoethylenically unsaturated monomers such as hydroxy lower methacrylate, acrylic acid and methacrylic acid with allyl methacrylate or polyfunctional monomer.

  The hard layer is a layer of an acrylic polymer having a Tg of 25 ° C. or higher, and is composed of alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms alone or as a main component, and other alkyl methacrylate, alkyl acrylate, styrene, substituted It may be a cross-linked polymer made of a copolymer of a monofunctional monomer such as styrene, acrylonitrile, methacrylonitrile and the like, and further polymerized by adding a polyfunctional monomer. As the rubber-like polymer described above, for example, those described in JP-B-55-27576, JP-A-6-80739, JP-A-49-23292 and the like can be used.

  In a graft copolymer obtained by graft-polymerizing an ethylenically unsaturated monomer at a ratio of 95 to 20 parts by weight to 5 to 80 parts by weight of a rubbery polymer, examples of the rubbery polymer include polybutadiene rubber and acrylonitrile. / Butadiene copolymer rubber, diene rubber such as styrene / butadiene copolymer rubber, acrylic rubber such as polybutyl acrylate, polypropyl acrylate, poly-2-ethylhexyl acrylate, and ethylene / propylene / non-conjugated diene rubber Etc. Examples of the ethylenic monomer include styrene, acrylonitrile, alkyl (meth) acrylate, and the like, and an acrylic unsaturated monomer is preferable. These may be used alone or in combination of two or more. Also good. As the above-mentioned graft copolymer, for example, those described in JP-A Nos. 55-147514 and 47-9740 can be used.

  The addition amount of the rubber-like polymer is preferably 0 to 100 parts by weight, and more preferably 3 to 50 parts by weight with respect to 100 parts by weight of the methyl (meth) acrylate resin. If the amount of the rubbery polymer added is too large, the rigidity of the extruded plate is lowered, which is not preferable.

  The thermoplastic resin includes, for example, a light diffusing agent, a matting agent, an ultraviolet absorber, a surfactant, an impact resistant agent, a polymer antistatic agent, an antioxidant, a flame retardant, a lubricant, depending on the purpose. Dyes, pigments and the like may be added.

  The temperature at which the thermoplastic resin is melt-kneaded is not particularly limited, and may be appropriately set in consideration of the melting point of the thermoplastic resin to be used.

  The molten resin melt-kneaded by the extruder is co-extruded from a die, cooled by at least three cooling rolls, and formed into a laminated extruded resin plate. Hereinafter, with reference to FIG. 1, the manufacturing method of the laminated extrusion resin board which concerns on this invention is demonstrated in detail.

  FIG. 1 is a schematic explanatory view showing a method for producing a laminated extruded resin plate according to an embodiment of the present invention. As shown in FIG. 1, a thermoplastic resin is put into extruders 1 and 2 and melt-kneaded as described above. In FIG. 1, two extruders are used, but the number of extruders may be three or more depending on the number of resin layers stacked and the type of resin used, and may be changed as appropriate.

  The melt-kneaded resin is supplied to the die 3 and coextruded as a plate-like molten resin 4 from the die 3. As shown in FIG. 1, when two extruders are used, a plate-like molten resin in which the thermoplastic resin is melt-kneaded in each of the extruders 1 and 2 and co-extruded from the die 3 and laminated and integrated. 4 is obtained.

  Examples of the extruders 1 and 2 include a single screw extruder and a twin screw extruder. As the die 3, a T die, a multi-manifold die, or the like is used. When a T die is used, it is usually used in combination with a feed block.

  The molten resin 4 extruded from the die 3 is molded and cooled by the cooling unit 5. In FIG. 1, the cooling unit 5 includes three cooling rolls 51, 52, and 53 arranged to face each other in a substantially horizontal direction. The cooling rolls 51, 52, and 53 are a first cooling roll 51, a second cooling roll 52, and a final cooling roll 53 in order along the direction of taking the molten resin 4. These cooling rolls 51, 52, and 53 are configured such that at least one roll is connected to a rotation driving means (not shown) such as a motor, and each roll rotates at a predetermined peripheral speed.

  The cooling rolls 51, 52, 53 are not particularly limited, and normal cooling rolls used in conventional extrusion molding can be employed. Specific examples include a drilled roll, a spiral roll, a metal elastic roll, and a rubber roll. The surface state of the cooling rolls 51, 52, 53 may be, for example, a mirror surface, or may have a pattern or unevenness. In FIG. 1, three cooling rolls are used, but there are no particular limitations as long as there are three or more, such as four or five.

  The molten resin 4 is sandwiched between a final cooling roll 53 and a cooling roll (second cooling roll) 52 immediately before the final cooling roll 53, and is pressed with a gap of a target thickness. By being pressure-bonded in this way, the laminated extruded resin plate 6 is obtained in which surface roughness is suppressed and the appearance is good. The thickness of the laminated extruded resin plate 6 is not particularly limited, and for example, the laminated extruded resin plate 6 is preferably 300 to 2000 μm, more preferably 500 to 1500 μm.

  When the molten resin 4 is sandwiched between the final cooling roll 53 and the second cooling roll 52, a layer made of a resin other than the resin having the highest thermal deformation temperature is sandwiched so as to contact the final cooling roll 53. FIG. 2 shows an enlarged view of a portion surrounded by a broken line in FIG. As shown in FIG. 2, for example, when the molten resin 4 is composed of two types of thermoplastic resin layers, the thermoplastic resin constituting the resin layer 42 that contacts the final cooling roll 53 does not contact the final cooling roll 53. It has a lower heat deformation temperature than the thermoplastic resin constituting the resin layer 41.

  When the molten resin 4 is composed of three or more layers, the layer made of the resin having the highest thermal deformation temperature may be an intermediate layer other than the resin layer 42 in contact with the final cooling roll 53. The layer (surface layer) which contacts the cooling roll 52 may be used.

  The surface temperature (Tr) of the cooling rolls 51, 52, 53 is set in consideration of the thermal deformation temperature (Th) of the thermoplastic resin that constitutes the resin layer in contact with each of the cooling rolls 51, 52, 53. Preferably, (Th−20 ° C.) ≦ Tr ≦ (Th + 20 ° C.), and more preferably (Th−20 ° C.), with respect to the thermal deformation temperature (Th) of the thermoplastic resin constituting the resin layer in contact with each cooling roll 51, 52, 53. (Th−15 ° C.) ≦ Tr ≦ (Th + 10 ° C.), more preferably (Th−10 ° C.) ≦ Tr ≦ (Th + 5 ° C.). When the surface temperature (Tr) is lower than (Th-20 ° C.), the resin tends to be peeled off from the roll and a touch error tends to occur. Further, when the surface temperature (Tr) is higher than (Th + 20 ° C.), it becomes difficult for the resin to be uniformly peeled from the roll, and tack marks are likely to be generated.

  In the method for producing a laminated extruded resin plate according to the present invention, after molding (that is, after peeling from the final cooling roll), the heater 7 is the most heat deformation temperature of the thermoplastic resin constituting the laminated extruded resin plate 6. At least one surface of the laminated extruded resin plate 6 is heated at a high heat deformation temperature or higher. Thus, since the difference of the cooling rate in the upper and lower surfaces of the laminated extrusion resin board 6 can be made small by heating with a heater, the lamination extrusion resin board 6 in which curvature was suppressed is obtained. Usually, the laminated extruded resin plate 6 flows on a traveling roll (not shown) after being peeled off from the final cooling roll 53. Since the lower surface (contact surface with the final cooling roll 53) of the laminated extruded resin plate 6 is in contact with the stored traveling roll, the cooling rate is slower than the upper surface of the laminated extruded resin plate 6. Therefore, it is preferable to heat the upper surface of the laminated extruded resin plate 6 that is more easily cooled (that is, the non-contact surface with the final cooling roll 53).

  The heater 7 is not particularly limited as long as the laminated extruded resin plate 6 can be heated, and examples thereof include a far infrared heater, a hot air heater (hot air generator), and the like. Heating is performed at a temperature equal to or higher than the highest thermal deformation temperature (MaxTh) of the thermoplastic resins constituting the laminated extruded resin plate 6, preferably MaxTh to (MaxTh + 50 ° C.), more preferably ( Heating is performed in the range of MaxTh + 5 ° C.) to (MaxTh + 30 ° C.). Moreover, the time to heat is not specifically limited, Preferably it is 1-500 second, More preferably, it is 5-300 second. The heating time refers to the time from when a certain point on the surface of the laminated extruded resin plate 6 starts to be heated by the heater 7 until the point goes out of the heater 7 and is not heated.

  According to the method for producing a laminated extruded resin plate according to the present invention, as described above, two or more kinds of thermoplastic resins having a difference in heat deformation temperature of 10 ° C. or more are used and sandwiched between cooling rolls under specific conditions. Since the laminated extruded resin plate obtained by pressure bonding and molding is heated, a laminated extruded resin plate having a good appearance, no tack mark, and further suppressed warpage deformation is obtained. The thus obtained laminated extruded resin plate is used in a wide range of lighting covers, signboards, building materials, touch panel substrates, liquid crystal display front plates, light guide plates, and the like.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to these Examples.

The configuration of the extrusion apparatus used in the examples and comparative examples is as follows.
Extruder 1: An extruder with a screw diameter of 130 mm, a single screw, and a vent (manufactured by Hitachi Zosen Corporation).
Extruder 2: Screw diameter 50 mm, single screw, vented extruder (manufactured by Hitachi Zosen).
Die (I): T-die (resin discharge port width 1650 mm, lip interval 1 mm (manufactured by Hitachi Zosen)) and feed block (resin discharge port width 150 mm, 2-type 3-layer distribution (manufactured by Hitachi Zosen)) Combination with.
Die (II): T die (resin discharge port width 1650 mm, lip interval 1 mm (manufactured by Hitachi Zosen)) and feed block (resin discharge port width 150 mm, 2-type 2-layer distribution (manufactured by Hitachi Zosen)) Combination with.
Cooling unit: Horizontal type, 3 cooling rolls with surface length of 1800mm and diameter of 350mmφ

Resins used in Examples and Comparative Examples are as follows.
Polycarbonate resin (PC): “Caliber 301-10” manufactured by Sumitomo Dow Co., Ltd. (thermal deformation temperature = 140 ° C.)
Methacrylic resin (PMMA): Copolymer of methyl methacrylate / methyl acrylate = 98/2 (mass ratio) (thermal deformation temperature = 100 ° C.)
Heat-resistant acrylic resin: “ACRYPURE AX1-MR1000” manufactured by Nippon Shokubai Co., Ltd. (thermal deformation temperature = 120 ° C.)

(Examples 1-4 and Comparative Examples 1-8)
The resins shown in Table 1 were melted and kneaded in the first extruder and the second extruder, respectively, and supplied to a feed block to which a T-die was attached to perform coextrusion molding. The resin charged in the extruder 1 forms an intermediate layer (in the case of a three-layer structure) or a main layer (in the case of two layers), and the resin charged in the extruder 2 is formed in both surface layers (three-layer structure). Or a surface layer (in the case of two layers).

  Next, the extruded molten resin was cooled and molded by a cooling unit having three cooling rolls, and two layers having a total thickness (target value) described in Table 1 (Example 1, Comparative Examples 1 and 2). Alternatively, a laminated extruded resin plate having three layers (other than Example 1 and Comparative Examples 1 and 2) was produced. In Examples 1 to 4, after peeling from the final cooling roll, the upper surface of the laminated extruded resin plate (non-contact surface with the final cooling roll) is further heated by a heater (a far-red panel heater manufactured by Hitachi Zosen Corporation). The mixture was heated at the temperature shown in Table 1 for 10 seconds.

  The laminated extruded resin plates obtained in Examples 1 to 4 and Comparative Examples 1 to 8 were cut into a size of width 275 mm × length 400 mm, and placed on a surface plate, the degree of lifting of the four corners, Measurement was performed using a gap gauge. The measured values of the four corners obtained were averaged to obtain the amount of warpage (mm). In addition, the case where the corner | angular part has floated on the heater irradiation side (upper surface of a laminated extrusion resin board) was shown by the negative (-) value, and the case where it floated conversely was shown by the positive (+) value. Moreover, the external appearance was evaluated visually. These results are shown in Table 1.

  As shown in Table 1, the laminated extruded resin plates obtained in Examples 1 to 4 had good appearance without surface roughness and tack marks, and the degree of warpage was very small (± 0.5 mm or less).

  On the other hand, in Comparative Examples 1, 3, 5 and 7, the molten resin is sandwiched between the final cooling roll and the cooling roll immediately before the final cooling roll and is crimped (molded). Since it was not heated after peeling, the degree of warping was remarkably large. In Comparative Examples 2 and 4, the molten resin is sandwiched between the final cooling roll and the cooling roll immediately before the final cooling roll and is not pressure-bonded, and is not heated after peeling from the final cooling roll. The surface of the extruded resin plate was rough and the degree of warpage was remarkably large. In Comparative Examples 6 and 8, since the temperature of the final cooling roll is set high instead of heating after peeling from the final cooling roll, the degree of warpage is good, but a tack mark is generated on the laminated extruded resin plate. did.

DESCRIPTION OF SYMBOLS 1, 2 Extruder 3 Die 4 Molten resin 41, 42 Resin layer 5 Cooling unit 51, 52, 53 Cooling roll 6 Laminated resin board 7 Heater

Claims (3)

Resin having the highest heat distortion temperature and resin having the lowest heat deformation temperature are melt-kneaded with two or more thermoplastic resins having a difference in heat deformation temperature of 10 ° C. or more, respectively, and coextruded from the die. A method for producing a laminated extruded resin plate that is molded and cooled with at least three cooling rolls to obtain a laminated extruded resin plate,
Between the cooling rolls, the molten resin is sandwiched between the final cooling roll and the cooling roll immediately before the final cooling roll so that the layer made of the resin other than the resin having the highest thermal deformation temperature is in contact with the final cooling roll. To obtain a laminated extruded resin plate by pressure bonding with
Heating at least one of both surfaces of the laminated extruded resin plate at a temperature equal to or higher than the highest thermal deformation temperature of the two or more thermoplastic resins constituting the laminated extruded resin plate by a heater A method for producing a laminated extruded resin plate.   The manufacturing method of Claim 1 which heats a non-contact surface with the last cooling roll of the said laminated extrusion resin board.   The heating by the heater is performed in the range of MaxTh to (MaxTh + 50 ° C), where MaxTh is the highest thermal deformation temperature of the thermoplastic resin constituting the laminated extruded resin plate. The manufacturing method as described in.

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