JP2004059595A - Polystyrene resin extruded foam plate and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polystyrene resin extruded foam plate produced by using isobutane having 0 ozone depletion potential and a small global warming potential as a blowing agent, having excellent flame retardance and low thermal conductivity. <P>SOLUTION: The polystyrene resin extruded foam plate is obtained by extruding a foamable molten resin mixture comprising a mixed blowing agent containing the isobutane (except a chlorofluorocarbon and/or a fluorocarbon) and a polystyrene resin from a high-pressure zone to a low-pressure zone and has ≥10 mm thickness and 25-60 kg/m<SP>3</SP>apparent density. The residual amount of the isobutane in the foam plate is 0.45-0.80 mol based on 1 kg of the foam plate. Furthermore, the foam plate has 0.05-0.18 mm average cell diameter in the thickness direction and 0.7-1.2 cell deformation ratio (the average cell diameter in the thickness direction/the average cell diameter in the horizontal direction) and satisfies type 3 of the flammability standard of the polystyrene extruded foam heat insulating plate described in JIS A9511(1995) and further has ≤0.028 W/mK thermal conductivity of the foamed plate. <P>COPYRIGHT: (C)2004,JPO

Description

【００７５】
【表２】

【００７６】
表２における見掛け密度は、ＪＩＳ　Ｋ７２２２（１９８５）に基づいて測定された値である。
【００７７】
表２における厚みは、幅方向を４等分する位置の３箇所で測定し、それらを相加平均した値である。
【００７８】
表２における厚み方向平均気泡径及び気泡変形率は、前記の方法で測定された値である。
【００７９】
表２における独立気泡率は、押出発泡板から２５ｍｍ×２５ｍｍ×２０ｍｍのサイズに切断された成形表皮を持たないカットサンプルを使用して上記の方法で測定された値である。
【００８０】
表２における熱伝導率は、製造後４週間経過した押出発泡板と製造後３ヶ月経過した押出発泡板のそれぞれに対し、縦２０ｃｍ、横２０ｃｍ、押出発泡板厚みの試験片を切り出し、各試験片について、ＪＩＳ　Ａ　９５１１（１９９５）４．７の記載により、英弘精機株式会社製の熱伝導率測定装置「オートΛ　ＨＣ−７３型」を使用して、ＪＩＳ　Ａ１４１２（１９９４）記載の平板熱流計法（熱流計２枚方式、平均温度２０℃）に基づいて測定した。
【００８１】
表２における燃焼性は、ＪＩＳ　Ａ９５１１（１９９５）の４．１３．１「測定方法Ａ」に基づいて測定した。
【００８２】
表２における発泡剤残存量（発泡板１ｋｇ当たりの発泡剤の含有量）の測定は、株式会社島津製作所製、島津ガスクロマトグラフＧＣ−１４Ｂを使用し、シクロペンタンを内標準物質として、前記方法に基づいて測定した。
【００８３】
【発明の効果】
本発明のポリスチレン系樹脂押出発泡板は、厚み１０ｍｍ以上、密度２５〜６０ｋｇ／ｍ^３であって、発泡板１ｋｇ当り０．４５〜０．８０モルのイソブタンを含むが、クロロフルオロカーボンやフルオロカーボンは含まない。従って、本発明の押出発泡板から放出される発泡剤は、オゾン破壊係数が０であり、地球温暖化係数も小さいので、地球環境に対して優しいものである。又、イソブタンは、ポリスチレンに対する透過速度が空気より極めて遅いので、本発明の押出発泡板は長期にわたって製造時の断熱性が維持される。
【００８４】
本発明のポリスチレン系樹脂押出発泡板は、ＪＩＳ　Ａ９５１１（１９９５）記載の押出ポリスチレンフォーム保温板３種の燃焼性規格を満足する。従って、本発明の押出発泡板は、着火した場合であっても、火が燃え広がる可能性が小さいので、建材用の押出ポリスチレンフォーム保温板として要求される安全性を備えるものである。
【００８５】
本発明のポリスチレン系樹脂押出発泡板は、熱伝導率が０．０２８Ｗ／ｍ・Ｋ以下である。従って、本発明押出発泡板は、ＪＩＳ　Ａ９５１１（１９９５）記載の押出ポリスチレンフォーム保温板３種についての熱伝導率の規格を満足するものであり、建材用の断熱板として好適なものである。
【００８６】
また、本発明のポリスチレン系樹脂押出発泡板は、厚み方向の平均気泡径が０．０５〜０．１８ｍｍであると共に、気泡変形率が０．７〜１．２であるから、製造が容易であり、寸法安定性や圧縮強度に優れ、断熱性にも優れたものとなる。
【００８７】
本発明のポリスチレン系樹脂押出発泡板の製造方法においては、溶融ポリスチレン系樹脂と、特定範囲内のイソブタンと他の発泡剤（クロロフルオロカーボン又は／及びフルオロカーボンを除く。）とからなる発泡性溶融樹脂混合物を、ダイリップを通して連続的に低圧域に押出し、押出された発泡途上の発泡性溶融樹脂混合物を、ダイに密着する特定構造の通路を発泡させながら通過させて、得られる押出発泡板に対して特定範囲の関系が成立するように圧縮し、続いて賦形装置を通過させながら板状に賦形するので、前記ポリスチレン系樹脂押出発泡板を容易に得ることができる。
【００８８】
本発明方法においては、前記混合発泡剤が、イソブタン９０〜５０モル％と、塩化アルキル、二酸化炭素、ジメチルエーテル、ジエチルエーテル及びメチルエチルエーテルの群から選ばれた１又は２以上の他の発泡剤１０〜５０モル％とからなるという構成を採用すると、前記本発明のポリスチレン系樹脂押出発泡板を容易に得ることができる。
【図面の簡単な説明】
【図１】本発明のポリスチレン系樹脂発泡板の製造方法に使用される通路、賦形装置の一例を示す図面である。
【符号の説明】
１　　　　ダイ
２　　　　ダイリップ
３　　　　通路
４　　　　通路の上面の壁
５　　　　通路の下面の壁
８　　　　通路の入口
９　　　　通路の出口
１０　　　　賦形装置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polystyrene resin extruded foam plate used as a heat insulating material for building walls, floors, roofs and the like, a tatami mat core material and the like, and a method for producing the same.
[0002]
[Prior art]
BACKGROUND ART Conventionally, polystyrene-based resin foams have excellent heat insulating properties and suitable mechanical strength, and therefore, those formed into a plate shape have been widely used as heat insulating materials. As a method for producing such a foamed board, a production method is known in which a foam adjusting agent is added to a polystyrene-based resin material, and after heating and melt-kneading, a physical foaming agent is added and the mixture is extruded from a high-pressure region to a low-pressure region. .
[0003]
Conventionally, chlorofluorocarbons (hereinafter, referred to as CFCs) such as dichlorodifluoromethane have been widely used as a foaming agent used for producing the foamed board. However, since CFCs have a high risk of destruction of the ozone layer, hydrogen atom-containing fluorinated hydrocarbons (hereinafter, referred to as HCFCs) having a small ozone depletion coefficient have been used in place of CFCs in recent years.
[0004]
However, since the ozone depletion coefficient of HCFC is not 0, there is no possibility that the ozone layer is destroyed. Therefore, the use of a fluorocarbon (hereinafter, referred to as HFC) having an ozone depletion potential of 0 and no chlorine atom in the molecule as a foaming agent has been studied.
[0005]
However, since this HFC has a large global warming potential, there is room for improvement in protecting the global environment.
[0006]
Therefore, it is desired to produce an extruded polystyrene resin foam board using an environmentally friendly foaming agent having an ozone depletion potential of 0 and a low global warming potential.
[0007]
Isobutane, on the other hand, has an ozone depletion potential of 0, a low global warming potential, and is an excellent foaming agent from the viewpoint of being environmentally friendly. Further, since the permeation rate of polystyrene is much lower than that of air, the foamed insulating board using isobutane can maintain the heat insulating property at the time of production for a long period of time.
[0008]
However, isobutane has a lower thermal conductivity in the gaseous state than air, but has a higher thermal conductivity in the gaseous state than CFCs, HCFCs, and HFCs that have been used so far, and has the same heat insulation properties as HFCs and the like. It is difficult. Furthermore, because of its high flammability, it is very difficult to impart flame retardancy to the obtained foam.
[0009]
[Problems to be solved by the invention]
The present invention is a foamed board manufactured using isobutane having a zero ozone depletion potential and a small global warming potential as a blowing agent in view of the drawbacks of the conventional extruded polystyrene resin foamed board, and has excellent flame retardancy. It is another object of the present invention to provide a polystyrene resin extruded foam plate having a low thermal conductivity.
[0010]
[Means for Solving the Problems]
The present invention relates to a method for extruding a foamable molten resin mixture containing a mixed foaming agent containing isobutane (excluding chlorofluorocarbon and / or fluorocarbon) and a polystyrene resin from a high pressure range to a low pressure range. Obtained thickness 10mm or more, apparent density 25-60kg / m ³ Extruded polystyrene resin foam board, wherein the residual amount of isobutane in the foam board is 0.45 to 0.80 mol per 1 kg of the foam board, and the foam board has an average cell diameter of 0 in the thickness direction. 0.05 to 0.18 mm, a cell deformation ratio (average cell diameter in the thickness direction / average cell diameter in the horizontal direction) of 0.7 to 1.2, and heat retention of the extruded polystyrene foam described in JIS A9511 (1995). A polystyrene-based resin extruded foam plate, which satisfies the flammability standards of the three types of plates and the thermal conductivity of the foam plate is 0.028 W / m · K or less; 1 to 10 parts by weight per 100 parts by weight of the extruded polystyrene resin foam plate according to the above [1], [3] 100 parts by weight of hexabromocyclododecane, polystyrene resin The extruded polystyrene resin foam plate according to the above [1] or [2], wherein the apparent density of the foamed plate is 36 to 60 kg / m. ³ The extruded polystyrene resin foam board according to any one of the above [1] to [3], [5] the method for producing an extruded polystyrene resin foam board according to the above [1], wherein In the machine, the molten polystyrene resin is composed of 90 to 50 mol% of isobutane and 10 to 50 mol% of another blowing agent (excluding chlorofluorocarbon and / or fluorocarbon) (however, the total amount of these blowing agents is The mixed foaming agent and an additive including a flame retardant are kneaded to form a foamable molten resin mixture, and then continuously extruded from a high pressure region to a low pressure region through a die lip to form the foamable molten resin mixture. In shaping into a plate while foaming, the extruded foaming molten resin mixture in the process of being foamed is surrounded by four walls, up, down, left and right, which are in close contact with the die, At the very least, the foamable molten resin mixture is compressed by passing it through a passage in which the distance between the upper and lower surfaces expands and contracts from the inlet to the outlet, and then expands, and then passes through the shaping device. While expanding in at least the thickness direction and the width direction, and shaping into a plate while regulating at least the thickness direction, the thickness (T: mm) and width (W: mm) of the obtained extruded polystyrene resin foam plate ) And the height (h: mm) and width (b: mm) of the passage having the smallest cross-sectional area in the passage closely contacting the die satisfy the following expressions (1) to (3). So that a method for producing an extruded polystyrene resin foam board characterized by being compressed in the passage,
[0011]
## EQU4 ## W / b ≧ 1.08 (1)
[0012]
T / h ≧ 1.20 (2)
[0013]
(W / b) / (T / h) ≧ 0.90 (3)
[0014]
And [6] the mixed blowing agent is 90 to 50 mol% of isobutane, 10 to 50 mol% of one or more other blowing agents selected from the group consisting of alkyl chloride, carbon dioxide, dimethyl ether, diethyl ether and methyl ethyl ether. (However, the sum of the amounts of these foaming agents is 100 mol%.) The gist of the method for producing a polystyrene resin extruded foam board according to the above [5] is characterized in that:
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
An extruded polystyrene resin foam board (hereinafter, referred to as an extruded foam board) of the present invention is a foamable molten resin mixture containing a mixed foaming agent containing isobutane (excluding chlorofluorocarbon and / or fluorocarbon) and a polystyrene resin. By extruding the foamable molten resin mixture from a high pressure range to a low pressure range. That is, the extruded foam plate of the present invention supplies an extruder with a polystyrene-based resin and additives such as a flame retardant and a cell regulator, and then heats and melts and kneads the mixture to form a molten resin mixture, which contains isobutane under high pressure However, a mixed foaming agent that does not contain chlorofluorocarbon or fluorocarbon is press-fitted and kneaded to form a foamable molten resin mixture.Then, the foamable molten resin mixture is adjusted to an appropriate foaming temperature, and then pressed from a high pressure range to a low pressure range. Manufactured by serving. The extruded foam board manufactured in this manner has a high thickness, a low apparent density, excellent dimensional stability, and is friendly to the global environment.
[0016]
As the polystyrene resin used in the present invention, for example, styrene homopolymer or styrene-based styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-maleic anhydride copolymer, styrene- Examples thereof include a butadiene copolymer, a styrene-acrylonitrile copolymer, an acrylonitrile-butadiene-styrene copolymer, and high impact polystyrene. These may be used alone or as a mixture of two or more. The styrene component content in the styrene copolymer is preferably at least 50 mol%, particularly preferably at least 80 mol%.
[0017]
The polystyrene resin used in the present invention has a melt flow rate (MFR) in the range of 0.5 to 30 g / 10 min (however, MFR measured according to test condition 8 of method A of JIS K7210 (1976)). It is more preferable to use one having a viscosity of 1 to 10 g / 10 min, because the extruded foamed board obtained is excellent in mechanical strength and the obtained extruded foamed board has excellent mechanical strength. .
In the present invention, other (co) polymers such as a polyolefin resin, a styrene-based elastomer, and a polyphenylene ether resin may be further mixed with the polystyrene resin within a range not to impair the object of the present invention. However, the amount of such other (co) polymer is preferably up to 50 parts by weight, more preferably 0 to 30 parts by weight, and more preferably 0 to 10 parts by weight, per 100 parts by weight of the polystyrene resin. Is more preferred.
[0018]
The extruded foam board of the present invention is manufactured using a mixed foaming agent containing isobutane (excluding chlorofluorocarbon and / or fluorocarbon). The mixed blowing agent contains isobutane, but does not contain chlorofluorocarbon or fluorocarbon. Therefore, the foaming agent contained in the extruded foam board of the present invention has an ozone depletion potential of 0 and a small global warming potential, and is environmentally friendly. In addition, since the permeation rate of isobutane with respect to polystyrene is much lower than that of air, the extruded foamed plate of the present invention maintains the heat insulating property during production for a long period of time.
[0019]
The residual amount of isobutane in the extruded foam board of the present invention is 0.45 to 0.80 mol per kg of the foam board. If the remaining amount of isobutane is less than 0.45 mol, it may not be possible to obtain the high heat insulation required as a heat insulating material for building materials. Specifically, there is a possibility that an extruded foamed board having three types of heat conductivity (0.028 W / m · K or less) of an extruded polystyrene foam insulation board described in JIS A9511 (1995) may not be obtained. On the other hand, when it exceeds 0.80 mol, the flame retardancy required as a building material may not be obtained. Specifically, there is a possibility that the three types of extruded polystyrene foam insulation plates described in JIS A9511 (1995) cannot be satisfied with the flammability standards.
In consideration of the above, it is preferable that the residual amount of isobutane in the extruded foam board of the present invention is 0.50 to 0.75 mol per 1 kg of the foam board.
[0020]
As the other foaming agent contained in the mixed foaming agent, one or more foaming agents selected from the group consisting of alkyl chlorides such as methyl chloride and ethyl chloride, carbon dioxide, dimethyl ether, diethyl ether and methyl ethyl ether are preferable. Used for Since these other foaming agents have a high foaming power, they have the effect of lowering the apparent density of the obtained extruded foam board, and have a high gas permeability to polystyrene, so that they escape from the extruded foam board at an early stage, and the foam board has This is effective for stabilizing the heat insulation performance and the flame retardancy of the steel at an early stage. On the other hand, even if the isobutane foaming agent is left at room temperature for 5 years after the production of the foamed board, the isobutane foaming agent only slightly comes out of the foamed board and does not show a significant decrease. This is considered to contribute to maintaining the high heat insulating property of the heat insulating plate of the present invention. It is not so preferable to use an aliphatic hydrocarbon other than isobutane such as propane or normal butane as another blowing agent. Since aliphatic hydrocarbons other than isobutane escape from the foam board not so late, when used in large amounts, the heat insulation performance of the foam board may be significantly reduced at an early stage. However, a small amount can be used in combination within a range that does not impair the object of the present invention. When an aliphatic hydrocarbon other than isobutane is used in combination as another blowing agent, the content is preferably 5 mol% or less, more preferably 3 mol% or less, and more preferably 1 mol% or less in the mixed blowing agent. More preferably, it is.
[0021]
The residual amount of the blowing agent in this specification is measured using a gas chromatograph. Specifically, a sample cut out from the center of the extruded foam board was placed in a sample bottle with a lid containing toluene, and after closing the lid, the foaming agent in the extruded foam board was thoroughly stirred with toluene. The residual amount of isobutane, alkyl chloride, and the like contained in the foamed board is determined by performing gas chromatography analysis on the sample dissolved in water.
[0022]
The measurement conditions of gas chromatography analysis are as follows.
column:
Manufacturer: Shinwa Kako Co., Ltd.
Carrier: Chromosorb W, mesh 60-80, AW-DMCS treated product
Liquid phase: Silicone DC550 (liquid phase amount 20%)
Column dimensions: column length 4.1m, column inner diameter 3.2mm
Column material: glass
Packed column baking conditions: 220 ° C, 40 hours
Column temperature: 40 ° C
Inlet temperature: 200 ° C
Carrier gas: nitrogen
Carrier gas velocity: 3.5 ml / min
Detector: FID
Detector temperature: 200 ° C
Quantitation: Internal standard method
[0023]
The apparent density of the extruded foam board is 25kg / m ³ If it is less than 30, it is very difficult to produce such an extruded foam having an apparent density itself, and the mechanical properties of the obtained extruded foam plate are inferior to those of the conventional foam insulation plate. Since it is sufficient, usable applications are limited. Further, when the apparent density of the extruded foam plate is reduced, the flame retardancy may be deteriorated. Therefore, the foamed board of the present invention has an apparent density of 36 kg / m. ³ It is preferable that it is above. On the other hand, the apparent density is 60 kg / m ³ If the thickness exceeds, it is difficult to exhibit sufficient heat insulating properties unless the thickness is increased more than necessary, and there is a possibility that the weight may be insufficient. In particular, in the present invention, the apparent density of the extruded foam board is 36 to 60 kg / m. ³ In the case of, it is easy to give high heat insulating performance, and when hexabromocyclododecane, which has been used for a long time, is used as a flame retardant for this kind of foam board, it gives high flame retardancy with a relatively small amount of use. There is an advantage that can be.
[0024]
The extruded foam board of the present invention satisfies the flammability standard for extruded polystyrene foam insulation boards described in JIS A9511 (1995). That is, when the flammability is measured according to 4.13.1 “Measurement method A” described in JIS A9511 (1995), the flame is extinguished within 3 seconds, there is no residue, and the combustion limit indication line is set. Does not burn over. Therefore, the extruded foam board of the present invention has the safety required for an extruded polystyrene foam heat insulating board for building materials, since the fire is less likely to spread even when ignited.
[0025]
The extruded foam board of the present invention has a thermal conductivity of 0.028 W / m · K or less. Such a thermal conductivity satisfies the thermal conductivity standards for three types of extruded polystyrene foam insulation plates described in JIS A9511 (1995), and the extruded foamed plate of the present invention is suitable as a heat insulating plate for building materials. It is. The thermal conductivity is a value measured by a flat plate heat flow meter method (two heat flow meter method, average temperature of 20 ° C.) described in JIS A 1412 (1994).
[0026]
The thickness of the extruded foam plate of the present invention is at least 10 mm, preferably at least 15 mm, more preferably at least 20 mm, because high heat insulation performance is required. If the thickness is too thin, high heat insulating performance may not be obtained. The upper limit of the thickness of the extruded foam board of the present invention is not particularly limited, but is preferably 200 mm or less, more preferably 150 mm or less, and still more preferably 120 mm or less from the viewpoint of ease of production.
Moreover, in the extruded foam board of the present invention, the average cell diameter in the thickness direction is preferably 0.05 to 0.18 mm. When the average cell diameter is less than 0.05 mm, the foaming molten resin mixture which is being foamed and extruded through a die lip during production (changes from a "molten" state to a "non-molten state" with the passage of time after extrusion) Strictly speaking, this may include a state that is not necessarily “melted”, but this expression is used for convenience in the present specification). May not be possible. On the other hand, if the average bubble diameter exceeds 0.18 mm, the desired heat insulating property may not be obtained. From such a viewpoint, the average cell diameter in the thickness direction of the extruded foam board of the present invention is preferably 0.08 to 0.15 mm, and more preferably 0.07 to 0.14 mm.
[0027]
The measuring method of the average bubble diameter in this specification is as follows. A vertical section in the width direction at the center selected at random in the width direction (horizontal direction perpendicular to the extrusion direction) of the foam board is shown on a screen or photomicrograph in a state where the microscope is enlarged 200 times with a microscope. Air bubbles (a part of the air bubble is missing at the edge of the screen or photo, or a part of the air bubble wall that is not the edge of the screen or photo but communicates with the next air bubble etc. 20 bubbles are selected at random. At this time, when less than 20 bubbles show the whole view on the screen or the micrograph, another screen or another micrograph of the same cross section may be additionally used. Next, for each of the selected bubbles, draw a rectangle or square in contact with the bubble wall. At this time, a pair of opposing sides of a rectangle or a square is made to coincide with the thickness direction of the foam board, and another opposite side of the rectangle or the square is made to coincide with a width direction of the foam board. For each of the 20 rectangles or squares thus obtained, the length of the side in the direction coinciding with the thickness direction of the foam board and the length of the side in the direction coinciding with the width direction of the foam board were measured. By arithmetically averaging each direction, the average cell diameter (D _T : Mm) and average cell diameter (D) in the width direction of the foam plate _W : Mm).
[0028]
In addition, the average cell diameter (D _L : Mm), except that the pair of opposing sides of the rectangular or square is matched with the extrusion direction of the foam board using a cross section perpendicular to the extrusion direction at a randomly selected central portion in the width direction of the foam board. , D _W Is the same as the measurement method. In addition, the average cell diameter (D _H : Mm) is D _W And D _L Is the arithmetic mean value of
The average cell diameter in any direction of the foam board is an arithmetic mean value based on measurements on three different cross sections.
[0029]
In the extruded foam board of the present invention, the cell deformation rate is 0.7 to 1.2. The bubble deformation rate refers to the D value obtained by the above measurement method. _T To D _H (D) _T / D _H The smaller the bubble deformation ratio, the flatter the bubble, and the larger the bubble deformation ratio, the longer the bubble. When the cell deformation ratio is less than 0.7, the cells are flat, and the compressive strength in the thickness direction may be reduced, and the flat cells have a strong tendency to return to a circular shape. There is a risk of lowering. If the bubble deformation ratio exceeds 1.2, the number of bubbles in the thickness direction is reduced, so that a desired high heat insulating property may not be obtained. From such a viewpoint, the bubble deformation rate is preferably 0.80 to 1.15, and more preferably 0.85 to 1.10.
[0030]
The foam board of the present invention preferably has a cell structure having a substantially uniform size as a whole. Although it is possible to mix large bubbles and small bubbles as described in Japanese Patent Publication No. 5-49701, a bubble structure having a substantially uniform size as a whole has better mechanical properties. Is preferred because of its excellent uniformity.
[0031]
The extruded foam board of the present invention preferably contains at least 2 parts by weight of hexabromocyclododecane based on 100 parts by weight of the polystyrene resin. Hexabromocyclododecane has the effect of making a polystyrene resin foam board flame-retardant, but if it is less than 2 parts by weight, it satisfies the three types of flammability standards of extruded polystyrene foam heat insulation boards described in JIS A9511 (1995). May not be possible. The upper limit of the content of hexabromocyclododecane is approximately 10 parts by weight from the viewpoint of not inhibiting the formation of bubbles during extrusion foaming. Hexabromocyclododecane is a flame retardant generally used for this type of foam board. In the present invention, it is sufficient to use such a general flame retardant, and it is sufficient to use a special flame retardant (for example, ammonium phosphate or polyphosphate). High flame retardancy can be imparted to the foamed board without using or using a phosphorus-based flame retardant such as ammonium).
[0032]
Next, a method for producing the extruded foam board of the present invention will be described.
First, an additive containing a polystyrene resin and a flame retardant is put into an extruder, heated, melted and kneaded, and then 90 to 50 mol% of isobutane and another blowing agent (excluding chlorofluorocarbon and / or fluorocarbon) 10 are added. A mixed foaming agent consisting of 50 mol% (the total amount of these foaming agents is 100 mol%) is press-fitted, and further heated and kneaded to form a foamable molten resin mixture.
[0033]
As the flame retardant used in the method of the present invention, hexabromocyclododecane is preferably used as in the case of the extruded foam plate, and at least 2 parts by weight is added to 100 parts by weight of the polystyrene resin.
[0034]
In the method of the present invention, for example, a bubble regulator is added to the base resin as an additive other than the flame retardant. The cell regulator is an additive for adjusting the average cell diameter of the extruded foam board. Examples of the cell regulator include inorganic powders such as talc, kaolin, mica, silica, calcium carbonate, barium sulfate, titanium oxide, clay, aluminum oxide, bentonite, and diatomaceous earth. In the present invention, two or more cell regulators are used. They can be used in combination. Among the various cell regulators, talc is preferably used because the cell diameter is easily adjusted and the flame retardancy is not hindered, and the cell diameter is easily reduced. Talc is preferred.
[0035]
When talc is used as the cell regulator, its addition amount is 1 to 10 parts by weight, preferably 2 to 8 parts by weight, per 100 parts by weight of the polystyrene resin.
[0036]
In the method of the present invention, various additives such as a coloring agent, a heat stabilizer, and a filler can be added as appropriate, in addition to the above-mentioned bubble regulator and flame retardant, as long as the purpose is not hindered.
[0037]
In the method of the present invention, 90 to 50 mol% of isobutane and 10 to 50 mol% of another blowing agent (excluding chlorofluorocarbon and / or fluorocarbon) are used (provided that the total amount of these blowing agents is 100 mol%). The mixed foaming agent is used. If a mixed foaming agent having an isobutane content outside the above range is used, there is a possibility that an extruded foamed board having a residual isobutane content of 0.45 to 0.80 mol per kg of the extruded foamed board may not be obtained.
[0038]
Further, since the mixed foaming agent does not contain chlorofluorocarbon or fluorocarbon, the foaming agent contained in the extruded foam plate obtained by the method of the present invention has an ozone destruction coefficient of 0 and a small global warming coefficient. So it is friendly to the global environment. In addition, since isobutane has a permeation rate to polystyrene much lower than that of air, the extruded foamed board obtained by the present invention maintains the heat insulating property at the time of production for a long time.
[0039]
As the other foaming agent, as described above, one or more foaming agents selected from the group consisting of alkyl chlorides such as methyl chloride and ethyl chloride, carbon dioxide, dimethyl ether, diethyl ether and methyl ethyl ether are preferably used. You. Since these other foaming agents have a high foaming power, they have the effect of lowering the apparent density of the obtained extruded foam board, and have a high gas permeability to polystyrene, so that they escape from the extruded foam board at an early stage, and the foam board has This is effective for stabilizing the heat insulation performance and the flame retardancy of the steel at an early stage. In particular, the use of carbon dioxide is preferable because it has the effect of reducing the air bubbles in the obtained foamed board, so that the amount of the air bubble adjusting agent can be reduced.
[0040]
In the method of the present invention, after adjusting the foamable molten resin mixture to a suitable foaming temperature, the foamable molten resin mixture is extruded continuously from a high pressure range to a low pressure range through a die lip to form a plate while foaming the foamable molten resin mixture. Specifically, first, the foamable molten resin mixture is foamed while being passed through a passage having a specific structure, thereby compressing the foamable molten resin mixture in the course of foaming, and then into a plate shape while passing through a shaping device. Shape.
[0041]
The foaming suitable temperature refers to a temperature within a range in which the foamable molten resin mixture exhibits a viscosity suitable for foaming, the type of polystyrene resin to be used, the presence or absence of a fluidity improver (if added, the type and the like) Amount), the amount of the mixed foaming agent, the components of the mixed foaming agent, etc., but it is generally 110 to 130 ° C. in the case of a normal styrene homopolymer.
[0042]
FIG. 1 shows an example of the passage having the specific structure and the shaping apparatus used in the method of the present invention.
FIG. 1 is a longitudinal sectional view of a die attached to a tip of an extruder, a passage having a specific structure, and a shaping apparatus. In FIG. 1, 1 is a die, 2 is a die lip, 3 is a passage of a specific structure, 4 is an upper wall, 5 is a lower wall, 6 is a support plate of the upper wall 4, and 7 is a lower surface. 8 is the entrance of the passage, 9 is the exit of the passage, 10 is the shaping device, 11 is the upper parallel plate of the shaping device, and 12 is the lower plate of the shaping device. Reference numeral 13 denotes a support plate of the upper parallel plate 11, and reference numeral 14 denotes a support plate of the lower parallel plate 12.
[0043]
The passage 3 having the specific structure is surrounded by four walls (upper, lower, left and right) that are in close contact with the die 1, and at least the interval between the upper and lower surfaces is once enlarged and then reduced from the entrance to the exit. That is, the passage 3 is surrounded by four walls, an upper wall 4, a lower wall 5, a left wall, and a right wall, which are in close contact with the die 1 (however, the left wall and the right wall are not shown). ), An inlet 8 and an outlet 9, and the inlet 8 is configured to be in close contact with the die 1, and at least the space between the upper and lower surfaces is once enlarged toward the outlet 9 and then reduced.
In addition, the space between the left and right surfaces of the passage 3 may be configured such that it temporarily increases toward the outlet 9 or decreases toward the outlet 9.
[0044]
When extruded through the die lip 2, the foamable molten resin mixture starts foaming in the passage 3 immediately after being extruded. Therefore, by taking up the foamable molten resin mixture that is being foamed at a speed corresponding to the discharge amount, It is possible to compress while foaming in the passage 3 having the above structure. That is, since the passage 3 is reduced at least after the interval between the upper and lower surfaces increases from the inlet 8 toward the outlet 9, the interval between the passages 3 is reduced by taking the foaming molten resin mixture in the middle of foaming at an appropriate speed. In the portion expanding toward the outlet 9, the foamable molten resin mixture in the process of foaming can be relatively freely foamed, and at the same time, the portion contracting toward the outlet 9, in particular, can be compressed while being foamed at the outlet 9. it can.
[0045]
The walls of the passages, such as the upper wall 4 and the lower wall 5, are preferably made of a material having a good sliding property with the foaming molten resin mixture during foaming, for example, made of a fluororesin such as polytetrafluoroethylene resin.
[0046]
In the method of the present invention, the foaming molten resin mixture in the process of foaming is passed through the passage 3, and then the foaming molten resin mixture in the process of foaming is passed through the shaping device 10 to form a plate-like extruded foam plate. Form. That is, the foaming molten resin mixture in the middle of foaming pulled out from the outlet 9 of the passage 3 is continuously foamed inside the shaping apparatus 10 composed of two parallel plates 11 and 12, so that the parallel plates 11 and 12 to form a plate-like extruded foam plate.
[0047]
When forming the extruded foam plate in the shaping apparatus 10, by appropriately adjusting the take-off speed, by expanding the foamable molten resin mixture in the middle of foaming at least in the thickness direction and the width direction while passing through the shaping apparatus 10. A space between at least two upper and lower parallel plates 11 and 12 is formed to form a plate-shaped extruded foam plate while regulating at least the thickness direction. Expanding at least in the thickness direction and the width direction means that expansion can also be performed in the extrusion direction, depending on the balance between the discharge amount of the foamable molten resin mixture and the take-up speed of the foamable molten resin mixture during foaming. . In addition, in addition to the two upper and lower parallel plates, when a further parallel plate (square material) is provided between the two upper and lower parallel plates and near both ends thereof, the foaming molten resin mixture in the process of foaming is mixed with the above-mentioned mixture. The space between the parallel plates (squares) provided near both ends can also be filled to regulate the width direction.
[0048]
The shaping apparatus 10 used in the method of the present invention is usually composed of at least two upper and lower parallel plates 11 and 12 whose both side surfaces are open to the atmosphere. The at least two upper and lower parallel plates are not limited to the upper and lower two parallel plates, but as described above, the parallel plates so as to close both ends in the width direction of the shaping passage between the upper and lower parallel plates ( Square material) may be provided. The material of the parallel plate (square material) is not particularly limited, but polytetrafluoroethylene is used in order to smooth the surface of the extruded foam plate obtained by reducing the frictional resistance with the foamable molten resin mixture during foaming. It is preferable to use a plate made of a fluororesin such as a resin.
[0049]
In the method of the present invention, the thickness (T: mm) and width (W: mm) of the obtained extruded foam plate and the die 1 are brought into close contact with each other when the foamable molten resin mixture being foamed is compressed in the passage 3. Compression so that the relationship between the height (h: mm) and the width (b: mm) of the portion of the passage 3 where the cross-sectional area is the smallest, satisfies the following expressions (1) to (3). Cost.
In the present invention, the “portion where the cross-sectional area of the passage closely contacting the die has the smallest cross-section” refers to the largest cross-sectional area of the passage 3 on the downstream side from the portion where the cross-sectional area of the enlarged portion of the passage 3 becomes the largest Refers to the part where becomes smaller. At this time, the cross-sectional area of the passage 3 means the cross-sectional area of the passage 3 when cut in a direction orthogonal to the extrusion direction. The portion of the passage 3 having the smallest cross-sectional area is usually the outlet 9 of the passage 3 or a parallel portion of the passage 3 connected to the outlet 9.
[0050]
(7) W / b ≧ 1.08 (1)
[0051]
T / h ≧ 1.20 (2)
[0052]
(W / b) / (T / h) ≧ 0.90 (3)
[0053]
In order to satisfy both of the above equations (1) and (2), the foaming molten resin mixture in the course of foaming should be mixed with the largest cross-sectional area in the passage 3 at a stage where the foaming force is still large at a very early stage after leaving the die lip. Means passing through a portion where becomes smaller. Since the foaming force is considerably reduced (W / b is less than 1.08 or / and T / h is less than 1.20), the passage 3 is passed through the portion having the smallest cross-sectional area to obtain a foamed plate. The cell diameter in the thickness direction cannot be reduced, and as a result, it is difficult to maintain the cell deformation rate at 1.2 or less, and there is a possibility that high heat insulating properties cannot be imparted to the heat insulating plate.
[0054]
Further, even when W / b is equal to or smaller than T / h, the cell diameter in the thickness direction of the obtained foamed plate cannot be reduced, and as a result, the cell deformation rate is maintained at 1.2 or less. This makes it difficult to impart high heat insulating properties to the heat insulating plate. In order to easily obtain a foamed plate having a cell deformation ratio of 0.7 to 1.2, each of W / b, T / h, and (W / b) / (T / h) is represented by the following formula ( It is preferable to perform compression so as to satisfy 4) to 6).
[0055]
## EQU10 ## 3.0 ≧ W / b ≧ 1.20 (4)
[0056]
[Expression 11] 2.0 ≧ T / h ≧ 1.30 (5)
[0057]
2.0 ≧ (W / b) / (T / h) ≧ 0.92 (6)
[0058]
As described above, compressing the foaming molten resin mixture in the course of foaming in the passage 3 is the most excellent means for producing a foamed plate having the above-described cell deformation rate. However, in the method of the present invention, And other methods such as appropriately selecting the take-up speed, lip clear, and lip width.
[0059]
According to the method of the present invention described above, the extruded foam board of the present invention can be easily manufactured. The closed cell rate of the foamed board thus obtained is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. The higher the closed cell rate, the higher the heat insulation performance can be maintained. The closed cell ratio of the foamed board was measured using an air comparison type hydrometer 930 of Toshiba Beckman Co., Ltd. according to procedure C of ASTM-D2856-70 (cut from the extruded foamed board to a size of 25 mm × 25 mm × 20 mm). A cut sample having no molded skin is placed in a sample cup and measured, but if a 20 mm cut sample cannot be cut out in the thickness direction, for example, a cut sample having a size of 25 mm × 25 mm × 10 mm Can be measured in a sample cup at the same time.) Using the true volume Vx of the extruded foam plate (cut sample), the closed cell ratio S (%) is calculated by the equation (7), The average value of N = 3 was determined.
[0060]
(Equation 13)
S (%) = (Vx−W / ρ) × 100 / (Va−W / ρ) (7)
[0061]
Vx: true volume (cm) of the cut sample measured by the above method ³ ), Which corresponds to the sum of the volume of the resin constituting the cut sample and the total volume of the cells in the closed cell portion in the cut sample.
Va: apparent volume (cm) of the cut sample calculated from the outer dimensions of the cut sample used for measurement ³ ).
W: Total weight (g) of cut sample used for measurement.
ρ: Density of resin constituting the extruded foam board (g / cm ³ )
[0062]
【Example】
Next, the present invention will be described in more detail with reference to specific examples.
[0063]
Examples 1, 3, 4 and Comparative Examples 1, 2
The raw material is 100 parts by weight of polystyrene (G330C manufactured by Toyo Styrene Co.), and talc masterbatch (69% by weight of the polystyrene and 30% by weight of talc (High Filler # 12 manufactured by Matsumura Sangyo Co., Ltd.)) are used as a cell regulator. 16.7 parts by weight of a master batch comprising 1% by weight of zinc stearate), 3 parts by weight of hexabromocyclododecane as a flame retardant and a small amount of a stabilizer were mixed, and isobutane, methyl chloride, dimethyl ether, and carbon dioxide were mixed. The amounts shown in Table 1 (expressed as the amount of foaming agent injected per kg of polystyrene (mol / kg)) of the mixed blowing agents mixed in the proportions shown in Table 1 were used.
[0064]
The extruder has an extruder having a diameter of 65 mm (hereinafter, referred to as "first extruder"), an extruder having a diameter of 90 mm (hereinafter, referred to as "second extruder"), and an extruder having a diameter of 150 mm (hereinafter, referred to as "third extruder"). Extruder ") in series, and the mixed foaming agent was press-kneaded into the molten resin near the tip of the first extruder.
[0065]
The die lip has a resin outlet of 115 mm width and a gap of 1.5 mm (rectangular cross section) at the tip, and is surrounded by four upper, lower, left and right walls made of polytetrafluoroethylene resin at the tip of the die lip. At the same time, a passage in which the distance between the upper and lower surfaces once increased and decreased from the inlet to the outlet was attached to the die as shown in FIG.
[0066]
The thickness (T: mm), width (W: mm), height (h: mm), width (b: mm), and width (W) of the passage having the smallest cross-sectional area in the passage are obtained. / B, T / h, and the relationship between W / b and T / h were configured as shown in Table 1.
[0067]
The shaping apparatus was composed of two upper and lower parallel plates made of polytetrafluoroethylene resin, and the interval between the two upper and lower parallel plates was set as shown in Table 1 and attached to the passage as shown in FIG. .
[0068]
Using the above apparatus, a raw material such as a polystyrene resin is supplied to the first extruder, heated to 220 ° C., melt-kneaded, and a mixed foaming agent is pressed in near the tip of the first extruder to form a foamable molten resin. Then, the foamable molten resin mixture is converted into a mixture so that the temperature of the foamable molten resin mixture measured between the third extruder and the die becomes a temperature shown in Table 1 (shown as a foaming temperature in Table 1). The mixture was gradually cooled by a second extruder and a third extruder. Next, the set temperature of the die was set to 120 ° C., the set temperature of the die lip was set to 110 ° C., and the foamable molten resin mixture was extruded from the die lip at a discharge rate shown in Table 1. At this time, the pressure of the foamable molten resin mixture in the die is 30 kgf / cm. ² (Example 4 only 35 kgf / cm ² )showed that.
[0069]
The foaming molten resin mixture in the process of foaming extruded from the die lip is compressed while being foamed by passing through the passage while being foamed, and then formed into a plate shape while being filled with a shaping device. Was manufactured. The take-off speed at that time was as shown in Table 1.
[0070]
Table 2 shows the apparent density, thickness, closed cell ratio, average cell diameter in the thickness direction, cell deformation ratio, thermal conductivity, flammability, and remaining amount of the foaming agent of the obtained extruded foamed board.
[0071]
Example 2
An extruded foam board was manufactured in the same manner as in Example 1 except that the amount of the talc masterbatch was changed to 8.3 parts by weight. Table 2 shows the apparent density, thickness, closed cell ratio, average cell diameter in the thickness direction, cell deformation ratio, thermal conductivity, flammability, and remaining amount of the foaming agent of the obtained extruded foamed board.
[0072]
Comparative Example 3
An extruded foam board was manufactured in the same manner as in Example 1 except that the amount of the talc master batch was changed to 1.7 parts by weight. Table 2 shows the apparent density, thickness, closed cell ratio, average cell diameter in the thickness direction, cell deformation ratio, thermal conductivity, flammability, and remaining amount of the foaming agent of the obtained extruded foamed board.
[0073]
Comparative Example 4
Except for changing the passage used in Example 1 in which the interval between the upper and lower surfaces once expands from the inlet to the outlet and then decreases, to a passage in which the interval between the upper and lower surfaces gradually widens linearly from the inlet to the outlet. Produced an extruded foam board in the same manner as in Example 1. Table 2 shows the apparent density, thickness, closed cell ratio, average cell diameter in the thickness direction, cell deformation ratio, thermal conductivity, flammability, and remaining amount of the foaming agent of the obtained extruded foamed board.
[0074]
[Table 1]

[0075]
[Table 2]

[0076]
The apparent density in Table 2 is a value measured based on JIS K7222 (1985).
[0077]
The thickness in Table 2 is a value obtained by measuring at three places where the width direction is divided into four equal parts and arithmetically averaging them.
[0078]
The average cell diameter in the thickness direction and the cell deformation rate in Table 2 are values measured by the above method.
[0079]
The closed cell ratio in Table 2 is a value measured by the above method using a cut sample having no molded skin cut from an extruded foam plate into a size of 25 mm × 25 mm × 20 mm.
[0080]
The thermal conductivity in Table 2 was obtained by cutting out a test piece having a length of 20 cm, a width of 20 cm, and a thickness of the extruded foam plate for each of the extruded foam plate after 4 weeks from production and the extruded foam plate after 3 months from production. For the piece, a plate heat flow meter described in JIS A1412 (1994) was used according to JIS A 9511 (1995) 4.7 using a thermal conductivity measuring device “Auto II HC-73” manufactured by Eiko Seiki Co., Ltd. The measurement was carried out based on a method (two heat flow meters, average temperature 20 ° C.).
[0081]
The flammability in Table 2 was measured based on JIS A9511 (1995) 4.13.1 "Measurement method A".
[0082]
The measurement of the residual amount of the foaming agent (content of the foaming agent per 1 kg of foam board) in Table 2 was carried out by using a Shimadzu Gas Chromatograph GC-14B manufactured by Shimadzu Corporation and using cyclopentane as an internal standard substance according to the above method. It was measured based on.
[0083]
【The invention's effect】
The extruded polystyrene resin foam board of the present invention has a thickness of 10 mm or more and a density of 25 to 60 kg / m. ³ It contains 0.45 to 0.80 mol of isobutane per kg of foam board, but does not contain chlorofluorocarbon or fluorocarbon. Therefore, the blowing agent released from the extruded foam board of the present invention has an ozone depletion potential of 0 and a small global warming potential, and is therefore friendly to the global environment. In addition, since isobutane has a permeation rate to polystyrene much lower than that of air, the extruded foam plate of the present invention can maintain the heat insulating property during production for a long period of time.
[0084]
The extruded polystyrene resin foam board of the present invention satisfies the three types of flammability standards of the extruded polystyrene foam insulation board described in JIS A9511 (1995). Therefore, the extruded foam board of the present invention has the safety required for an extruded polystyrene foam heat insulating board for building materials, because even if it is ignited, the fire is less likely to spread.
[0085]
The extruded polystyrene resin foam board of the present invention has a thermal conductivity of 0.028 W / m · K or less. Therefore, the extruded foam board of the present invention satisfies the thermal conductivity standards for three types of extruded polystyrene foam insulation board described in JIS A9511 (1995), and is suitable as a heat insulating board for building materials.
[0086]
In addition, the extruded polystyrene resin foam board of the present invention has an average cell diameter in the thickness direction of 0.05 to 0.18 mm and a cell deformation rate of 0.7 to 1.2. It has excellent dimensional stability and compressive strength, and also has excellent heat insulating properties.
[0087]
In the method for producing an extruded polystyrene resin foam board of the present invention, a foamable molten resin mixture comprising a molten polystyrene resin, isobutane within a specific range, and another foaming agent (excluding chlorofluorocarbon and / or fluorocarbon). Is continuously extruded through a die lip to a low pressure region, and the extruded foaming molten resin mixture in the process of foaming is passed while foaming a passage having a specific structure in close contact with the die, and the extruded foamed plate obtained is specified. The extruded polystyrene resin foam plate can be easily obtained because the material is compressed so as to establish the relation of the range and then shaped into a plate while passing through a shaping device.
[0088]
In the method of the present invention, the mixed blowing agent comprises 90 to 50 mol% of isobutane and one or more other blowing agents selected from the group consisting of alkyl chloride, carbon dioxide, dimethyl ether, diethyl ether and methyl ethyl ether. By adopting a configuration of ５０50 mol%, the extruded polystyrene resin foam board of the present invention can be easily obtained.
[Brief description of the drawings]
FIG. 1 is a drawing showing an example of a passage and a shaping device used in the method for producing a polystyrene resin foam board of the present invention.
[Explanation of symbols]
1 die
2 die lip
3 passage
4 Upper wall of the passage
5 Wall on the lower side of the passage
8 Entrance of passage
9 Exit of passage
10 Shaping equipment

Claims (6)

An apparent thickness of 10 mm or more obtained by extruding a foamable molten resin mixture containing a mixed blowing agent containing isobutane (excluding chlorofluorocarbon and / or fluorocarbon) and a polystyrene-based resin from a high pressure range to a low pressure range. An extruded polystyrene resin foam board having a density of 25 to 60 kg / m ³ , wherein the remaining amount of isobutane in the foam board is 0.45 to 0.80 mol per 1 kg of the foam board. The average cell diameter in the direction is 0.05 to 0.18 mm, the cell deformation ratio (average cell diameter in the thickness direction / average cell diameter in the horizontal direction) is 0.7 to 1.2, and JIS A9511 (1995) The extruded polystyrene foam insulation plate satisfies the three types of flammability standards described above, and the thermal conductivity of the foamed plate is 0.028 W / m · K or less. Extruded polystyrene resin foam board that. 2. The extruded polystyrene resin foam board according to claim 1, wherein talc is contained in an amount of 1 to 10 parts by weight based on 100 parts by weight of the polystyrene resin. The extruded polystyrene resin foam board according to claim 1 or 2, wherein hexabromocyclododecane is contained in an amount of at least 2 parts by weight based on 100 parts by weight of the polystyrene resin. The polystyrene resin extruded foam board according to any one of claims 1 to ³ , wherein the foam board has an apparent density of 36 to 60 kg / m3. The method for producing an extruded polystyrene resin foam board according to claim 1, wherein in the extruder, the molten polystyrene resin, 90 to 50 mol% of isobutane, and another foaming agent (excluding chlorofluorocarbon and / or fluorocarbon). 10 to 50 mol% (the total amount of these blowing agents is 100 mol%). A mixed foaming agent and an additive containing a flame retardant are kneaded to form a foamable molten resin mixture, and then In order to extrude the foamable molten resin mixture into a plate while continuously extruding it from the high pressure range to the low pressure range through the die lip and foaming the foamable molten resin mixture, It is surrounded by four walls, and at least the space between the upper and lower surfaces expands from the entrance to the exit, and then passes through the passage, which expands and contracts while foaming By compressing the foaming molten resin mixture in the middle of foaming, and subsequently passing through a shaping device, expanding the molten resin mixture at least in the thickness direction and the width direction and shaping it into a plate while regulating at least the thickness direction. The thickness (T: mm) and width (W: mm) of the obtained extruded polystyrene resin foam board, and the height (h: mm) of the passage having the smallest cross-sectional area in the passage closely contacting the die. And a width (b: mm), wherein the compression is performed in the passage so that the following formulas (1) to (3) are satisfied.

The mixed blowing agent comprises 90 to 50 mol% of isobutane and 10 to 50 mol% of one or more other blowing agents selected from the group of alkyl chloride, carbon dioxide, dimethyl ether, diethyl ether and methyl ethyl ether. The method for producing a polystyrene resin extruded foam board according to claim 5, wherein the total amount of these foaming agents is 100 mol%.

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