JP7224977B2 - Method for manufacturing polycarbonate-based resin extruded foam board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a polycarbonate-based resin extruded foam board.

Polycarbonate resins are excellent in thermal properties, electrical properties, mechanical properties, etc., and are expected to be used in the fields of automobiles, construction, civil engineering, and the like. In particular, polycarbonate resin foams are excellent in heat insulating properties, heat resistance, flame retardant mechanical properties, and the like, and are used in a wide range of applications such as lightweight structural materials for building materials, heat insulating materials, and interior materials. In addition, polycarbonate resin extruded foam boards are known to have high termite resistance to prevent damage by termites, and are expected to grow in demand for construction applications.

Polycarbonate resin foam has a high utility value, but polycarbonate resin has a higher flow initiation temperature than general-purpose resin, and its melt viscosity and melt tension are low at processing temperatures. It is known that it is difficult to obtain a plate-like extruded foam by the extrusion foaming method as described in the above.

In addition, in fields such as building material applications, polycarbonate-based resin foamed boards are required to have heat insulation performance. In particular, in recent years, there has been a demand for a polycarbonate-based resin foam board that can maintain heat insulating properties over a long period of time.

As a method for producing a polycarbonate-based resin extruded foam board, for example, the methods of Patent Documents 1 to 3 are known.

Patent Document 1 discloses that a polycarbonate-based resin extruded foam board having a high cross-sectional area and a low apparent density can be produced by using a polycarbonate-based resin that satisfies a specific relationship between melt viscosity and melt tension as a base resin. Are listed. Further, in Patent Document 2, by using a polycarbonate-based resin modified with a thickener made of an acrylic copolymer having an epoxy group, a plate-like foam having high compressive strength at the ends in the width direction is obtained. It is stated that Patent Document 3 discloses that a mixture of a polycarbonate resin and a specific polyester resin is extruded and foamed to obtain a polycarbonate resin that has low thermal conductivity, excellent heat insulation over a long period of time, and excellent mechanical strength. It is said that a resin extruded foam is obtained.

JP-A-2006-199879 JP 2008-144084 A JP 2012-51971 A

However, the polycarbonate-based resin extruded foam boards described in Patent Documents 1 and 2 leave room for improvement in terms of heat insulation.

In addition, in the polycarbonate-based resin extruded foamed boards described in Patent Documents 1 to 3, when it is attempted to produce a particularly wide and thick extruded foamed board, the thickness variation in the width direction of the extruded foamed board tends to increase. tended to.

The present invention has been made in view of the above circumstances, and is suitable for manufacturing a wide and thick extruded foam board that is excellent in mechanical strength, flame retardancy, etc., and has excellent long-term heat insulation properties. It is an object of the present invention to provide a method for producing a polycarbonate-based resin foam board, which can obtain a polycarbonate-based resin foam board having excellent thickness accuracy in the width direction.

In order to solve the above problems, the present invention provides a polycarbonate-based resin extruded foam plate comprising a step of extruding and foaming a foamable molten resin kneaded product obtained by kneading a polycarbonate-based resin and a physical blowing agent to shape it into a plate shape. wherein the physical blowing agent contains a hydrofluoroolefin.

In this method for producing an extruded polycarbonate-based resin foam board, the total amount of the physical foaming agent added is preferably 0.05 to 0.8 mol per 1 kg of the polycarbonate-based resin.

In this method for producing a polycarbonate-based resin extruded foam board, the physical foaming agent further contains an aliphatic saturated hydrocarbon having 3 to 5 carbon atoms, and the hydrofluoroolefin and the aliphatic saturated hydrocarbon having 3 to 5 carbon atoms are It is more preferable that the ratio of the hydrofluoroolefin to 100 mol % in total with hydrogen is 5 to 50 mol %.

In this method for manufacturing an extruded polycarbonate resin foam board, it is more preferable that the extruded polycarbonate resin foam board is a foam board having a thickness of 30 mm or more and a width of 300 mm or more.

According to the method for producing a polycarbonate-based resin extruded foamed board of the present invention, by extrusion foaming using a physical foaming agent containing hydrofluoroolefin, excellent mechanical strength, flame retardancy, etc., as well as long-term heat insulation can be obtained. It is possible to obtain a polycarbonate-based resin foam board excellent in thickness accuracy in the width direction even when producing an excellent, wide, and thick extruded foam board.

An embodiment of the method for producing the polycarbonate-based resin extruded foamed board (hereinafter sometimes simply referred to as an extruded foamed board) of the present invention will be described below.

The method for producing a polycarbonate-based resin extruded foamed plate of the present invention comprises extruding and foaming an expandable molten resin kneaded product obtained by melt-kneading a polycarbonate-based resin and a physical foaming agent containing a hydrofluoroolefin to form a plate. This is a method of manufacturing a polycarbonate-based resin extruded foam board by shaping.

Specifically, in one embodiment of the method of the present invention, a base resin containing a polycarbonate-based resin as a main component is supplied to an extruder, heated and kneaded to obtain a molten resin kneaded product. Furthermore, a physical foaming agent is injected into the extruder to form a foamable molten resin kneaded product, and this foamable molten resin kneaded product is passed through a die attached to the outlet of the extruder and maintained at high pressure under atmospheric pressure or reduced pressure. A polycarbonate-based resin extruded foam board can be obtained by extruding to a lower pressure range than the die internal pressure under certain conditions. When producing an extruded foam board, it is preferable to use a flat die having a horizontal resin extrusion port, a slit die having a large number of vertical slits arranged in parallel, or a multi-hole die. Furthermore, immediately after extrusion foaming, it is preferable to shape the uncured foam by contacting and passing through a molding tool called a guider, which consists of upper and lower plates or an upper and lower belt conveyor. A flat extruded foam board can be obtained.

In the present invention, the polycarbonate-based resin refers to a polymer containing 50 mol % or more, preferably 70 mol % or more of a basic structural unit having a carbonic acid bond represented by the following general chemical formula (1).

上記一般化学式（１）において、Ｒはビスフェノール類の芳香族炭化水素である。

In the above general chemical formula (1), R is an aromatic hydrocarbon of bisphenols.

As the polycarbonate-based resin, for example, an aromatic polycarbonate resin produced by transesterification using a carbonate diester and an aromatic dihydroxy compound as raw materials in the presence of an alkali metal compound catalyst is preferably used. In the transesterification method, the starting aromatic dihydroxy compound is exemplified by the following. Specifically, 2,2-bis(bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (=bisphenol A) , 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3-t-butylphenyl)propane, 2,2-bis(4-hydroxy-3,5 -dimethylphenyl)propane, 1,1-bis(3-t-butyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane (=tetrabromobisphenol A) , 2,2-bis(3-bromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 2,2-bis(bis(4-hydroxyphenyl) heptane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(3,5-dichloro-4-hydroxyphenyl)cyclohexane, 1, 1-bis(3,5-dibromo-4-hydroxyphenyl)cyclohexane, 3,3'-5,5'-tetramethyl-4,4'-dihydroxyphenyl, 4-hydroxyphenyl, bis(4-hydroxyphenyl) sulfone, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ketone, etc. These aromatic dihydroxy compounds may be used alone or in combination of two or more. Among these, ethane, 2,2-bis(4-hydroxyphenyl)propane (=bisphenol A), 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2, 2-bis(4-hydroxy-3-t-butylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(3-t-butyl-4- hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane (=tetrabromobisphenol A) and the like are preferred.

Carbonic acid diesters include, for example, substituted diphenyl carbonates such as diphenyl carbonate and ditolyl carbonate, and dialkyl carbonates such as dimethyl carbonate, diethyl carbonate and di-t-butyl carbonate.

The polycarbonate resin preferably has a melt tension of 7 cN to 50 cN at 250°C. When the melt tension of the polycarbonate-based resin is within the above range, the polycarbonate-based resin is more excellent in foamability, so that it is possible to more easily produce a wide, high-thickness, low-apparent-density extruded foam board. From this point of view, the melt tension is more preferably 8 cN to 40 cN, even more preferably 9 cN to 30 cN, and particularly preferably 10 cN to 25 cN. Polycarbonate-based resins having such properties are preferably those having high-molecular-weight components or long-chain branches. Moreover, a polycarbonate-based resin having a melt tension lower than the above range can be mixed and used.

The melt tension of a polycarbonate-based resin can be measured by Capilograph 1D manufactured by Toyo Seiki Seisakusho Co., Ltd. Specifically, for example, using a cylinder with a cylinder diameter of 9.55 mm and a length of 350 mm and an orifice with a nozzle diameter of 2.095 mm and a length of 8.0 mm, the set temperature of the cylinder and orifice is 250 ° C., and a hot air circulation type A required amount of a sample (polycarbonate resin) dried at 120°C for 5 hours in a dryer is placed in a cylinder, left for 4 minutes, and the molten resin is extruded from an orifice at a piston speed of 10 mm/min. , This string-like material is hung on a pulley for tension detection with a diameter of 45 mm, and the string-like material is drawn by a take-up roller while increasing the take-up speed at a constant speed so that the take-up speed reaches 0 m/min to 200 m/min in 4 minutes. To obtain the maximum value of the tension just before the string-like article is broken by pulling the article. Here, the reason why the time required for the take-up speed to reach 200 m/min from 0 m/min is set to 4 minutes is to suppress thermal deterioration of the resin and improve the reproducibility of the obtained values. Using different samples for this operation, a total of 10 measurements were performed, and the 3 values in order from the highest maximum value obtained in 10 times and the 3 values in order from the lowest value of the maximum value were excluded. The value obtained by arithmetically averaging the remaining four intermediate maximum values is taken as the melt tension (cN).

The melt tension is measured by the method described above, and if the string does not break even when the take-up speed reaches 200 m / min, the melt tension (cN) obtained by setting the take-up speed to a constant speed of 200 m / min adopt the value of Specifically, in the same manner as in the above measurement, the molten resin is extruded from an orifice in the form of a string, and this string is hung on a pulley for detecting tension. Rotate the take-up roller while increasing the take-up speed at , and wait until the rotation speed reaches 200 m/min. When the rotation speed reaches 200 m/min, the acquisition of melt tension data is started, and after 30 seconds, the acquisition of data is terminated. The average value (Tave) of the maximum tension value (Tmax) and the minimum tension value (Tmin) obtained from the tension load curve obtained during the 30 seconds is taken as the melt tension. Here, Tmax is a value obtained by dividing the total value of the detected peak (mountain) values in the tension load curve by the number of detected dips (valleys) detected in the tension load curve. ) value divided by the number detected. When the molten resin is extruded from the orifice in the form of a string, the string should be free of air bubbles as much as possible.

Further, the melt viscosity of the polycarbonate-based resin is preferably 2×10 ³ Pa·s to 8×10 ³ Pa·s under conditions of 250° C. and a shear rate of 100 sec ⁻¹ . When the melt viscosity of the polycarbonate-based resin is within this range, the extrusion stability is excellent. From this point of view, the melt viscosity is more preferably 3×10 ³ Pa·s to 7×10 ³ Pa·s.

The melt viscosity of the polycarbonate-based resin is measured under the conditions of 250° C. and a shear rate of 100 sec−1 with a Capilograph 1D manufactured by Toyo Seiki Seisakusho Co., Ltd. Specifically, using a cylinder with a cylinder diameter of 9.55 mm and a length of 350 mm and an orifice with a nozzle diameter of 1.0 mm and a length of 10.0 mm, the temperature of the cylinder and orifice was set to 250 ° C., and a hot air circulation dryer was used. A measurement sample (polycarbonate resin) dried at 120° C. for 5 hours is placed in a cylinder and allowed to stand for 4 minutes before measurement, and the melt viscosity (Pa·s) obtained there is adopted. Air bubbles should be prevented from entering the strand extruded from the orifice at the time of measurement as much as possible.

Moreover, various resins can be included in the base resin contained in the foamable molten resin kneaded material in addition to the polycarbonate-based resin. Examples of resins other than polycarbonate-based resins include polystyrene-based resins, polyethylene-based resins, polyester-based resins, acrylic-based resins, and the like. An extruded foam board manufactured by blending a polyester resin as a base resin has excellent heat insulation properties over a long period of time.

The amount of other resins other than the polycarbonate-based resin is preferably less than 50 parts by weight, more preferably less than 30 parts by weight, and less than 20 parts by weight with respect to 100 parts by weight of the polycarbonate-based resin. is more preferred.

In the production method of the present invention, a hydrofluoroolefin (hereinafter sometimes referred to as HFO) is used as a physical blowing agent. A hydrofluoroolefin is a blowing agent that has a low ozone depletion potential, a very low global warming potential, and a low burden on the environment. In addition, it is known to have low thermal conductivity in the gaseous state and low flammability. By using hydrofluoroolefin as a physical blowing agent, the resulting extruded foam board has improved flame retardancy and excellent long-term heat insulation. Furthermore, an extruded foam board manufactured using hydrofluoroolefin as a physical foaming agent has good thickness accuracy in the width direction.

As described above, the polycarbonate-based resin extruded foam plate is shaped by a molding tool called a guider immediately after extrusion to produce a plate-like foam having a substantially rectangular cross section. Conventionally, when trying to manufacture a particularly wide and thick polycarbonate-based resin extruded foam board, there have been cases where the thickness of the extruded foam board varies in the width direction even after being shaped by a guider. . Such an extruded foam board with low thickness accuracy generates a large amount of offcuts when the extruded foam board is cut to a desired size. was desired.

In the manufacturing method of the present invention, by using hydrofluoroolefin as a physical foaming agent, a polycarbonate-based resin extruded foam board having good thickness accuracy in the width direction can be obtained even when a thick extruded foam board is manufactured. can be done. The reason for this is not clear, but by blending the hydrofluoroolefin as the physical foaming agent, the concentration of the physical foaming agent in the polycarbonate resin becomes uniform, and the extrusion foaming is performed more favorably, and the guider improves the This is considered to be because it can be shaped into

Hydrofluoroolefins used in the present invention include hydrofluoroolefins having 3 to 5 carbon atoms, more specifically trans-1,3,3,3-tetrafluoropropene (transHFO-1234ze), cis-1 , 3,3,3-tetrafluoropropene (cisHFO-1234ze), 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1-chloro-3,3,3-trifluoropropene (HFO- 1233zd) and the like. These hydrofluoroolefins also include hydrochlorofluoroolefins into which chlorine is partially introduced. These foaming agents can be used alone or in combination of two or more. Among them, it is preferable to use 1-chloro-3,3,3-trifluoropropene (HFO-1233zd) as the hydrofluoroolefin from the viewpoint of flame retardancy, heat insulation, handleability, and the like.

The amount of hydrofluoroolefin to be added is preferably 0.01 to 0.8 mol per 1 kg of polycarbonate resin. When the amount of hydrofluoroolefin to be added is within this range, the resulting extruded foam board has improved flame retardancy and excellent heat insulation over a long period of time. Furthermore, the thickness accuracy in the width direction of the obtained extruded foam board becomes better. From this point of view, the amount of hydrofluoroolefin to be added is more preferably 0.02 to 0.5 mol, more preferably 0.03 to 0.3 mol, per 1 kg of polycarbonate resin.

The physical blowing agent used in the production method of the present invention preferably contains an aliphatic saturated hydrocarbon having 3 to 5 carbon atoms in addition to the hydrofluoroolefin. Examples of aliphatic saturated hydrocarbons having 3 to 5 carbon atoms include one or more of normal propane, cyclopropane, isobutane, normal butane, cyclobutane, isopentane, normal pentane, cyclopentane, and the like. .

Among them, a mixture of normal butane (n-Bu) and isobutane (i-Bu) known as industrial butane (m-Bu) (n-Bu/i-Bu = 70/30 mixture) is converted to hydrofluoro Particular preference is given to using olefins together as physical blowing agents. As a result, it is possible to more easily produce an extruded foamed board having excellent mechanical strength and excellent thickness accuracy in the width direction while maintaining excellent flame retardancy, long-term heat insulation performance, etc. of the extruded foamed board.

In the production method of the present invention, the total amount of physical foaming agent added is preferably 0.05 to 0.8 mol per 1 kg of the polycarbonate resin. When the total addition amount of the physical foaming agent is within this range, an extruded foam board having a desired apparent density can be obtained more easily. From this point of view, the total amount of the physical foaming agent added is more preferably 0.1 to 0.6 mol, more preferably 0.2 to 0.45 mol, per 1 kg of the polycarbonate resin.

Also, the ratio of the hydrofluoroolefin to 100 mol% of the total of the hydrofluoroolefin and the aliphatic saturated hydrocarbon having 3 to 5 carbon atoms is preferably 5 to 50 mol%. When the ratio of the total addition amount of the physical foaming agent and the blending amount of the hydrofluoroolefin is within this range, the heat insulation properties and flame retardancy of the extruded foam board can be more reliably improved, and the thickness accuracy in the width direction can be improved. get better. From this point of view, the proportion of the hydrofluoroolefin compounded is more preferably 7 to 35 mol %, and even more preferably 10 to 25 mol %.

Furthermore, in the production method of the present invention, a cell control agent can be added in order to smoothly foam the foamable molten mixture containing the polycarbonate resin and the physical foaming agent. Examples of the cell control agent include inorganic powders such as talc and silica, acid salts of polyvalent carboxylic acids, mixtures of polyvalent carboxylic acids and sodium carbonate or sodium bicarbonate, and the like. The amount of the cell control agent to be added is preferably 0.01 to 1.0 parts by weight, more preferably 0.05 to 0.5 parts by weight, per 100 parts by weight of the base resin.

In addition, known additives that are added to ordinary foams, such as flame retardants, heat stabilizers, weather resistance improvers, and colorants, are added to the base resin, which is mainly composed of polycarbonate resin. be able to.

For example, additives include organic alkali metal salts such as sodium metaxylenesulfonate, sodium naphthalenesulfonate, sodium dichlorobenzenesulfonate, sodium perfluorobutanesulfonate, and potassium perfluorobutanesulfonate, organopolysiloxane, A suitable amount of a flame retardant improver such as a phosphorus-based flame retardant, polytetrafluoroethylene, or fibrillated polytetrafluoroethylene can be added in a timely manner. In particular, an organic alkali metal salt is preferable because it can improve flame retardancy even in a small amount.

In the production method of the present invention, the addition of a specific thickener further improves the foam moldability of the polycarbonate resin, making it possible to easily produce a foam having a high expansion ratio and a high closed cell ratio. Therefore, it is preferable. Examples of such thickeners include acrylic polymers having epoxy groups. The reason why such a thickener improves the foam moldability of the polycarbonate resin is that the epoxy group of the thickener is bonded to the end of the polycarbonate resin, and in the case of a linear polycarbonate resin, a branched structure is introduced. In the case of the branched polycarbonate resin, it is presumed that this is due to the introduction of a further branched structure.

The thickener may be obtained by polymerizing an acrylic monomer having an epoxy group, or may be a copolymer of an acrylic monomer having an epoxy group and another copolymerizable monomer. may In any case, the acrylic polymer having an epoxy group as a thickener may be a polymer or copolymer containing 5% by weight or more of acrylic monomer units having an epoxy group. The acrylic monomer unit having an epoxy group in the thickener is preferably 5% to 95% by weight, preferably 10% to 50% by weight, particularly preferably 15% to 40% by weight. If the content of the acrylic monomer unit having an epoxy group is too small, the amount of thickening agent used must be increased. lead to an increase.

Examples of acrylic monomers having an epoxy group include glycidyl (meth)acrylate and (meth)acrylic acid esters having a cyclohexene oxide structure. These can be used alone or in combination of two or more. Glycidyl (meth)acrylate is preferred. Incidentally, (meth)acrylic acid used in the above-mentioned glycidyl (meth)acrylate and the like is a comprehensive representation of acrylic acid and methacrylic acid. For example, glycidyl (meth)acrylate means glycidyl acrylate and glycidyl methacrylate.

Other copolymerizable monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (Meth)acrylic acid alkyl ester having an alkyl group having 1 to 22 carbon atoms (the alkyl group may be linear or branched) such as cyclohexyl (meth)acrylate, (meth)acrylic acid polyalkylene glycol ester, ( meth)acrylic acid alkoxyalkyl ester, (meth)acrylic acid hydroxyalkyl ester, (meth)acrylic acid dialkylaminoalkyl ester, (meth)acrylic acid benzyl ester, (meth)acrylic acid phenoxyalkyl ester, (meth)acrylic acid iso Bornyl esters, (meth)acrylic acid alkoxysilylalkyl esters, and the like can be mentioned. In addition, maleic anhydride, fumaric acid, (meth)acrylamide, (meth)acryldialkylamide, vinyl esters such as vinyl acetate, vinyl ethers, (meth)allyl ethers, aromatic vinyls such as styrene and α-methylstyrene Monomers include α-olefin monomers such as ethylene and propylene. These can be used alone or in combination of two or more.

The thickener is commercially available as an acrylic copolymer containing 10% to 50% by weight of an acrylic monomer unit having an epoxy group. For example, ARUFON UG series manufactured by Toagosei Co., Ltd. can be preferably used. Among them, ARUFON UG-4030, ARUFON UG-4035 and ARUFON UG-4040 are particularly preferred.

The thickener is added to the unmodified polycarbonate resin and melt-kneaded under heating, whereby the epoxy group of the thickener reacts with the carboxyl group at the end of the polycarbonate-based resin and bonds, resulting in thickening. It is considered that a high-molecular-weight modified polycarbonate resin having a long-chain branched structure is formed in which a plurality of polycarbonate-based resins are bonded to the viscous agent. As a result, when the modified polycarbonate resin is subjected to extrusion foaming, it becomes easy to form closed cells, and even if a large amount of foaming agent is added for high foaming, the molten resin pressure in the die can be sufficiently maintained. Therefore, premature foaming within the die can be suppressed. Therefore, an extruded foam board having excellent mechanical strength, light weight, etc. can be produced more easily.

Next, the properties of the extruded foam board manufactured by the method of the present invention will be described.

The extruded foam board preferably has a thickness of 10 mm or more, more preferably 30 mm or more, and even more preferably 50 mm or more. The upper limit of the thickness of the extruded foam board is approximately 120 mm.

The thickness of the extruded foam board shall be equal to or greater than 20 points, excluding both ends, of the widthwise vertical cross section of the extruded foam board (the cross section perpendicular to the extrusion direction of the extruded foam board). Then, the thickness of the extruded foam board is measured at each of the 20 or more measurement points, and the arithmetic mean value of the measured values can be obtained.

The extruded foam board preferably has a width of 300 mm or more, more preferably 350 mm or more, and even more preferably 400 mm or more. The upper limit of the width of the extruded foam board is about 2000 mm.

According to the manufacturing method of the present invention, even when an extruded foam board having a large thickness and a wide width is to be obtained, it is possible to easily manufacture an extruded foam board in which variations in thickness are well suppressed. . In the present invention, the variation in the thickness of the extruded foam board is specifically specified by the thickness precision R value in the width direction. According to the manufacturing method of the present invention, the thickness accuracy R value can be suppressed to less than 4.0, preferably 3.0 or less.

The thickness accuracy R value _in the width direction of the extruded foam board _is the difference ( (Th _m )−(Th _m )) [unit: mm].

Furthermore, the cross-sectional area of the extruded foam board is preferably 10 cm ² to 2000 cm ² , more preferably 40 cm ² to 1500 cm ² , still more preferably 75 cm ² to 1000 cm ² , and particularly preferably 100 cm ² to 500 cm ² . . If the cross-sectional area is 10 cm ² or more, the heat insulating properties and mechanical strength will be excellent in relation to the width and thickness.

The apparent density of the extruded foam board is preferably 40 kg/m ³ to 300 kg/m ³ , more preferably 45 kg/m ³ to 200 kg/m ³ , still more preferably 50 kg/m ³ to 150 kg/m ³ . is. If the apparent density is 40 kg/m ³ or more, sufficient mechanical strength, particularly excellent compressive strength, will be obtained. On the other hand, if it is 200 kg/m ³ or less, heat insulation, light weight, and flexibility are good, and secondary workability such as cutting is good, so that a wide variety of applications can be developed. The apparent density of the extruded foam board is the value of the apparent core density measured based on JIS K 7222:2005.

The closed cell ratio in the central portion of the extruded foam board is preferably 55% or more, more preferably 70% or more, and even more preferably over 80%. In addition, the closed cell ratio at the edge of the extruded foam board is 55% or more, preferably 70% or more, and particularly preferably 80% or more. When the closed cell content is within the above range, the compressive strength, bending strength, etc. are sufficient, and it can be used more preferably in a wide range of applications.

In the extruded foam board of the present invention, both the closed cell rate in the central portion and the closed cell rate in the end portions of the extruded foam board are preferably 55% or more, more preferably 70% or more, and more preferably 80%. It is more preferable that it is above.

Furthermore, the absolute value [|(A)-(B)|] of the difference between the closed cell rate (A) in the central portion of the extruded foam board and the closed cell rate (B) in the end portion is within 10%. It is preferably within 8%, more preferably within 8%. When the absolute value of the difference between the closed cell rate (A) in the central portion of the extruded foam board and the closed cell rate (B) in the end portions is within the above range, the closed cell rate of the extruded foam board extends across the width direction. It becomes uniform, and an extruded foam board with excellent thickness accuracy in the width direction is obtained. According to the manufacturing method of the present invention, by including hydrofluoroolefin as a physical foaming agent, the closed cell ratio of the extruded foam board tends to be uniform across the width direction.

The value of the closed cell ratio Fc (%) of the extruded foam board is the sum of the volume of the resin of the foam test piece and the volume of the closed cell portion by the air pycnometer method (method using an air comparison type hydrometer). It is a value calculated based on the following formula (1) by determining the actual volume Vx of a certain foam test piece.

Fc = {[Vx-Va(ρf/ρs)]/[Va-Va(ρf/ρs)]}×100
... (1)
However, in formula (1), Fc, Vx, Va, ρf, and ρs represent the following.
Fc: closed cell ratio (%)
Vx: Actual volume of foam test piece (cm ³ )
Va: Apparent volume of foam test piece (apparent volume calculated from external dimensions) (cm ³ )
ρf: Apparent density of foam test piece (g/cm ³ )
ρs: Density of the base resin of the foam test piece (g/cm ³ )

In the measurement of the closed cell rate of the extruded foam board, the test piece for measuring the closed cell rate at the width center is 25 mm in the extrusion direction, 25 mm in the width direction, and 25 mm in the width direction from the width direction center of the polycarbonate resin extruded foam board. A test piece having a thickness of 20 mm is cut out in the thickness direction, excluding the skin layer at the time of molding. At this time, the widthwise central portion of the extruded polycarbonate resin foam plate and the widthwise central portion of the test piece are made to coincide with each other.

In addition, a test piece for measuring the closed cell ratio at the width end portion was cut from both ends of the extruded foam board in the width direction to 50 mm, and from both ends of the remaining extruded foam board, 25 mm in the extrusion direction, A test piece is cut out to a size of 25 mm in the width direction and 20 mm in the thickness direction excluding the skin layer during molding. The independent cell content of the test pieces cut out from both ends is obtained in the same manner as the independent cell content of the width center portion, and the average value is taken as the closed cell content of the width end portion.

In addition, in the measurement of the closed cell rate at the center of the width and the closed cell rate at the width end, if the thickness of the test piece is less than 20 mm, multiple test pieces are stacked so that the total thickness approaches 20 mm. and measure.

The average cell diameter in the thickness direction of the extruded foam plate is preferably 0.08 mm to 3.0 mm. When the average cell diameter is within this range, the surface smoothness of the extruded foam board is excellent, and the basic physical properties of the base resin, such as compressive strength and heat insulating properties, can be exhibited sufficiently. From this point of view, the average cell diameter in the thickness direction is more preferably 0.2 to 2.5 mm, even more preferably 0.5 to 2.0 mm.

The method for measuring the average bubble diameter is as follows. The average cell diameter in the thickness direction of the extruded foam board (DT: mm) and the average cell diameter in the width direction of the extruded foam board (DW: mm) are determined by measuring the width direction vertical cross section of the extruded foam board (orthogonal to the extrusion direction of the extruded foam board) The average cell diameter (DL: mm) in the extrusion direction of the extruded foam plate is the vertical cross section of the extruded foam plate in the extrusion direction (parallel to the extrusion direction of the extruded foam plate, bisected at the center in the width direction) Obtain micrographs of vertical cross-sections). Next, draw a straight line in the direction to be measured on the magnified photograph, count the number of bubbles that intersect the straight line, and measure the length of the straight line (of course, this length is the length of the straight line on the magnified photograph). Determine the average bubble diameter in each direction by dividing the true length of the straight line considering the magnification of the photograph, not the length, by the number of bubbles counted.

To describe the method for measuring the average bubble diameter in detail, the average bubble diameter in the thickness direction (DT: mm) was measured by obtaining enlarged microscope photographs of a total of three locations, the central portion and both ends of the vertical cross section in the width direction, and on each photograph , draw a straight line across the entire thickness of the extruded foam board in the thickness direction, and from the length of each straight line and the number of bubbles intersecting the straight line, the average diameter of the bubbles existing on each straight line (length of the straight line / The number of intersecting bubbles) is obtained, and the arithmetic average value of the obtained average diameters at three locations is taken as the average bubble diameter in the thickness direction (DT: mm).

For the average cell diameter in the width direction (DW: mm), a total of three microscopic enlarged photographs of the center and both ends of the vertical cross section in the width direction are obtained. A straight line with a length that is 3 mm multiplied by the magnification factor is drawn in the width direction at the position where the The number of bubbles intersecting the straight line-1)) is obtained, and the arithmetic average value of the average diameters of the three obtained points is taken as the average bubble diameter in the width direction (DW: mm).

The average cell diameter in the extrusion direction (DL: mm) is obtained by cutting the extruded foam plate in the extrusion direction at the position where the width direction of the extruded foam plate is bisected. Magnified micrographs of a total of three parts were obtained, and on each photograph, a straight line with a length obtained by multiplying the magnification by 3 mm was drawn in the extrusion direction at the position where the extruded foam board was divided into two equal parts in the thickness direction. From the straight line and the number of bubbles intersecting the straight line, the average diameter of the bubbles existing on each straight line is obtained by the formula (3 mm / (number of bubbles intersecting the straight line - 1)), and the three points obtained are Let the arithmetic average value of an average diameter be an average bubble diameter (DL:mm) of an extrusion direction. The average cell diameter (DH: mm) in the horizontal direction of the extruded foam board is the arithmetic mean value of DW and DL.

Further, the extruded polycarbonate resin foam plate preferably has a cell deformation rate of 1.5 to 3.5. The bubble deformation ratio is a value (DT/DH) calculated by dividing DT obtained by the above measurement method by DH. The larger is the vertical length. When the cell deformation rate is within the above range, an extruded foam board having excellent mechanical strength and high heat insulating properties can be obtained. Moreover, it becomes an extruded foam board which is more excellent in termite resistance. From the above point of view, the cell deformation ratio is more preferably 1.8 to 3.2, and even more preferably 2.0 to 3.0.

According to the manufacturing method of the present invention, by including hydrofluoroolefin as a physical foaming agent, the cell deformation rate of the extruded foam board can be set within the preferred range described above. In addition, by further including an aliphatic saturated hydrocarbon having 3 to 5 carbon atoms as the physical foaming material, the cell deformation rate of the extruded foamed board can be more easily set within the above preferable range.

The thermal conductivity of the polycarbonate resin extruded foam plate in this specification is determined by the heat flow meter method described in JIS A1412-2 (1999) (one specimen, symmetrical configuration, high temperature side 38 ° C., low temperature side 8 ° C., average temperature 23°C). In accordance with ISO 11561, the thermal conductivity after a long period of time from the production can be evaluated by conducting an accelerated test as follows. According to this method, for example, a 30 mm thick foam board is sliced into 10 mm thick sheets immediately after production, and the thermal conductivity of the sliced foam board is measured 90 days after production. It corresponds to the value of the foam board after about 270 days.

An oxygen index can be used as an index of flame retardancy of an extruded foam board. The oxygen index of the extruded foam board is measured according to the combustion test method for polymeric materials by the oxygen index method described in JIS K7201-2 (2007).

The compressive strength of an extruded foam board is measured by the following method. First, from the central part of the extruded foam board in the width direction, a rectangular parallelepiped test piece without a molded skin is cut out so that the width is 50 mm, the width is 50 mm, and the thickness is 25 mm. At this time, the central portion of the extruded foam board in the width direction and the central portion of the test piece in the width direction are made to coincide with each other. Next, for this test piece, the compression speed is 10% × T mm / min (where T is the initial thickness of the test piece), and the load at 10% compression is calculated based on JIS K7220 (1999). , and this is divided by the pressure-receiving area of the test piece to calculate the compressive strength.

According to the production method of the present invention, by using a hydrofluoroolefin as a physical foaming agent, an extruded foamed board that is excellent in mechanical strength, flame retardancy, etc. and can maintain good heat insulation properties over a long period of time is produced. Obtainable. In addition, the apparent density can be reduced, the width can be increased, and the thickness can be increased. Therefore, the polycarbonate-based resin extruded foam board of the present invention can be used in a wide range of applications such as construction and civil engineering. Furthermore, according to the manufacturing method of the present invention, even when a wide and thick extruded foam board is manufactured, it is possible to obtain a polycarbonate-based resin foam board having excellent thickness accuracy in the width direction.

The method for producing the polycarbonate-based resin extruded foam board of the present invention is not limited to the above embodiments.

The method for producing the extruded polycarbonate resin foamed plate of the present invention will be described with reference to examples, but the method for producing the extruded polycarbonate resin foamed plate of the present invention is not limited to the following examples.

<1> Materials The following materials were used in the formulations shown in Table 3.

(1) Polycarbonate-based resins Polycarbonate-based resins shown in Table 1 were used.

（２）増粘剤
表２に示した増粘剤を使用した。増粘剤は非晶性ポリエチレンテレフタレート７０重量部に対して３０重量部配合してマスターバッチとしたものを使用した。

(2) Thickener The thickener shown in Table 2 was used. As the thickener, 30 parts by weight of the amorphous polyethylene terephthalate was added to 70 parts by weight of the amorphous polyethylene terephthalate to prepare a masterbatch.

（３）物理発泡剤
ｍ－Ｂｕ：ノルマルブタンとイソブタンとの混合ブタン（ｎ－Ｂｕ／ｉ－Ｂｕ＝７０／３０の混合物）
ｎ－Ｂｕ：ノルマルブタン
ＨＦＯ－１２３３ｚｄ：１－クロロ－３，３，３－トリフルオロプロペン
ｃ－Ｐ：シクロペンタン

(3) physical blowing agent m-Bu: mixed butane of normal butane and isobutane (mixture of n-Bu/i-Bu = 70/30)
n-Bu: normal butane HFO-1233zd: 1-chloro-3,3,3-trifluoropropene cP: cyclopentane

<2> Manufacturing method As extruders, an extruder with a diameter of 65 mm (hereinafter referred to as "first extruder"), an extruder with a diameter of 90 mm (hereinafter referred to as "second extruder") and an extruder with a diameter of 150 mm ( A "third extruder") connected in series was used. As a die, a die having a rectangular cross-sectional opening with a width of 115 mm and a gap of 3 mm at the tip was used.

As raw materials, the polycarbonate-based resins shown in Table 1 were blended at the blending ratios shown in Table 3, and 1.2 parts by weight of the thickener masterbatch and the foaming agent were added to 100 parts by weight of the polycarbonate-based resin. A mixture was used which was mixed in the ratio shown in .

A polycarbonate-based resin and a cell control agent were fed into the first extruder. The mixture was heated to about 300° C., melt-kneaded, and the foaming agent shown in Table 3 was injected into the molten resin near the tip of the first extruder in the amount shown in Table 3 to obtain an expandable molten resin mixture. Subsequently, the second and third extruders were used to adjust the resin temperature to that shown in Table 3 to obtain a foamable molten resin mixture. At the die pressure shown in Table 3, the foamable molten resin mixture was extruded from the die opening between the upper and lower plates of a molding device (guider) consisting of an upper plate and a lower plate mounted parallel to the downstream side of the die, and the inner surfaces of the upper and lower plates. A plate-like polycarbonate resin extruded foam board having a width of 400 mm was obtained by taking it with a take-up machine while cooling it to below the softening temperature by passing it in contact. The gap between guiders was set to 50 mm.

<3> Measurement and evaluation method The apparent density, thickness, average cell diameter in the thickness direction, average cell deformation rate, closed cell rate (central part, end part), and 10% compression strength of the extruded foam board were measured in the above-described manner. Measured by the method described in the morphology.

(Thickness accuracy R value)
Calculated by the method described above. That is _, the thickness accuracy R value in the width direction of the extruded foam board _is the difference (( Th _m )−(Th _m )).

(apparent density)
Three test pieces (width 350 mm×length 1820 mm×thickness 50 mm) were cut out from the extruded foam board, the apparent density was measured by the above method, and the arithmetic mean was taken.

(Thermal conductivity)
Three samples of (width 200 mm x length 200 mm x thickness 50 mm) were cut out from the entire extruded foam plate, and the test pieces were allowed to stand in an atmosphere of 23 ° C. and 50% humidity for 270 days. (1999), the thermal conductivity was measured according to the plate heat flow meter method (two heat flow meters method, high temperature side 38°C, low temperature side 8°C, average temperature 23°C), and the arithmetic mean was taken.

(oxygen index)
The oxygen index was measured according to the combustion test method for polymeric materials by the oxygen index method described in JIS K7201-2 (2007). Three test pieces were cut out from an extruded foam plate to a size of (width 10 mm x length 150 mm x thickness 50 mm). The one adjusted at 50% for 168 hours was used. A flame retardancy tester (ON-1D model manufactured by Suga Test Instruments Co., Ltd.) was used as a measuring instrument. The values obtained for the three specimens were arithmetically averaged.

(Moldability/Appearance)
The moldability and appearance of the extruded foam board were evaluated by observing the surface of the extruded foam board and using the following indices.
○: No cracks, chips, holes, spots, etc. ×: Poor appearance, cracks, chips, holes, spots, etc.

<4> Results Table 3 shows the characteristics and evaluation results of the polycarbonate-based resin extruded foam board obtained by the above-described manufacturing method.

表３に示したように、物理発泡剤としてハイドロフルオロオレフィン（ＨＦＯ－１２３３ｚｄ）を使用した実施例１－４の押出発泡板は、独立気泡率が高く、熱伝導率および酸素指数が良好であり、優れた難燃性、断熱性を有していることが確認された。また、実施例１－４は、１０％圧縮強さ、成形性・外観性も良好であり、特に幅方向の厚み精度に優れていることが確認された。また、物理発泡剤として、ハイドロフルオロオレフィン（ＨＦＯ－１２３３ｚｄ）とｍ－Ｂｕとを併用し、１００ｍоｌ％に対するハイドロフルオロオレフィンの配合量の割合が５～５０ｍоｌ％である実施例１－３は、実施例４と比較して、幅方向の厚み精度、１０％圧縮強さがより良好であった。

As shown in Table 3, the extruded foam board of Example 1-4 using hydrofluoroolefin (HFO-1233zd) as a physical blowing agent has a high closed cell rate and good thermal conductivity and oxygen index. , it was confirmed to have excellent flame retardancy and heat insulation. In addition, it was confirmed that Example 1-4 was excellent in 10% compressive strength, moldability and appearance, and was particularly excellent in thickness accuracy in the width direction. In addition, as a physical blowing agent, hydrofluoroolefin (HFO-1233zd) and m-Bu are used in combination, and the ratio of the amount of hydrofluoroolefin to 100 mol% is 5 to 50 mol%. Compared with Example 4, the thickness accuracy in the width direction and the 10% compressive strength were better.

On the other hand, the extruded foam boards of Comparative Examples 1 and 2 using cyclopentane (cP) as a physical foaming agent have a lower closed cell rate and a lower thermal conductivity than the extruded foam boards of Examples 1-4. The rate and oxygen index were also found to be poor. In addition, it was confirmed that the extruded foam boards of Comparative Examples 1 and 2 had a high thickness accuracy R value in the width direction, and that the thickness accuracy in the width direction was inferior to that of the extruded foam boards of Examples 1-4. rice field.

Claims (4)

A method for producing a polycarbonate-based resin extruded foamed plate, comprising a step of extruding and foaming a foamable molten resin kneaded product obtained by kneading a polycarbonate-based resin and a physical foaming agent to shape it into a plate shape,
The polycarbonate-based resin extruded foam plate has a thickness of 10 mm or more and a width of 300 mm or more,
A method for producing a polycarbonate-based resin extruded foam board, wherein the physical foaming agent contains a hydrofluoroolefin. 2. The method for producing an extruded polycarbonate resin foam board according to claim 1, wherein the total amount of said physical foaming agent added is 0.05 to 0.8 mol per 1 kg of said polycarbonate resin. The physical blowing agent further contains an aliphatic saturated hydrocarbon having 3 to 5 carbon atoms, and the hydrofluoroolefin with respect to the total 100 mol% of the hydrofluoroolefin and the aliphatic saturated hydrocarbon having 3 to 5 carbon atoms 3. The method for producing a polycarbonate-based resin extruded foam board according to claim 1 or 2, wherein the proportion is 5 to 50 mol %. 4. The method for producing an extruded polycarbonate resin foamed board according to any one of claims 1 to 3, wherein the extruded polycarbonate resin foamed board is a foamed board having a thickness of 30 mm or more and a width of 300 mm or more.