JP6685730B2 - Method for producing polystyrene-based resin extruded foam plate, and polystyrene-based resin extruded foam plate - Google Patents

Description

  The present invention relates to a method for producing a polystyrene-based resin extruded foam plate, and a polystyrene-based resin extruded foam plate.

  Conventionally, as a method for producing a plate-shaped polystyrene-based resin extruded foam, a flame retardant is added to polystyrene-based resin, and the mixture is heated and melted and kneaded in an extruder, and then a physical foaming agent is further pressed and kneaded into the extruder, and these are kneaded. High-thickness, low apparent density by extruding the molten mixture of from the high pressure region to the low pressure region (usually in the atmosphere) and forming it into a plate shape (shaping) with a shaping device connected to the die exit of the extruder. There is known a method for producing a polystyrene resin extruded foam plate (hereinafter also referred to as a foam plate), and a foam plate manufactured by the manufacturing method.

  The foamed plate produced in this manner is mainly used as a heat insulating material for walls, floors, roofs and the like of buildings and a heat insulating material for construction such as tatami core materials. When used for such an application, the extruded polystyrene foam heat insulation plate described in “Measurement method A” defined in JIS A9511 (2006R) 5.13.1 is targeted for the polystyrene resin extruded foam plate. It is required to have a high degree of flame retardancy that satisfies the flammability standard. Furthermore, the foamed plate is required to have excellent heat insulating properties that satisfy the standard of thermal conductivity defined by JIS A9511 (2006R) 4.2.

  Further, from the viewpoint of environmental protection, it is required to use a foaming agent that has a small global warming potential and does not destroy the ozone layer. The ozone depletion potential is 0 (zero), and the global warming potential is also small. Saturated hydrocarbons such as butane have come to be used as the main component of physical blowing agents.

  Saturated hydrocarbons have the above-mentioned advantages, but saturated hydrocarbons have the property of being easily combusted, so the amount used as a foaming agent is limited from the viewpoint of imparting flame retardancy to the foam plate, and high foaming In order to produce a foamed board with a magnification, it is necessary to use an easily dissipative physical foaming agent that quickly dissipates from the foamed board. Specifically, as an easily dissipative physical foaming agent, alkyl chlorides such as methyl chloride, ethers such as dimethyl ether, aliphatic alcohols such as ethanol, water, carbon dioxide, and foaming agents combining these have been used. It was

  Under these circumstances, in recent years, 1,3,3,3-tetrafluoropropene (hereinafter, also referred to as HFO1234ze) in which four of the six hydrogens of the propene containing a double bond are replaced with fluorine, and the like. , Hydrofluoropropene such as 1-chloro-3,3,3-trifluoropropene (hereinafter also referred to as HFO1233zd) in which 3 of 6 hydrogens are replaced by fluorine and 1 of hydrogen is replaced by chlorine. It has been developed. These hydrofluoropropenes have the properties of having an ozone depletion potential of 0 (zero) and an extremely small global warming potential. Furthermore, since hydrofluoropropene has a lower thermal conductivity than hydrocarbons and a slower rate of dissipation from the polystyrene resin foam plate than the easily dissipative physical foaming agent described above, HFO1234ze and HFO1233zd are used. Then, there is a possibility that a foamed plate having a low thermal conductivity for a long period of time can be obtained as compared with the conventional polystyrene resin extruded foamed plate.

Patent Documents 1 to 3 disclose polystyrene-based resin extruded foams using HFO1234ze and HFO1233zd, and a method for producing the same.
Specifically, Patent Document 1 describes the use of a physical foaming agent mainly containing HFO1234ze and a hydrocarbon such as butane or isobutane, a hydrofluorocarbon (HFC), or a hydrofluoroalkene other than HFO1234ze. In the examples, using a twin-screw extruder, polystyrene was used, and HFO1234ze alone or a mixture of HFO1234ze and HFC 1,1,1,3,3-pentafluoropropane (HFC245fa) was used as a foaming agent. It is described that a rod-shaped polystyrene foam having an apparent density of 70 to 100 kg / m ³ and a direct diameter of about 30 mm was obtained by injecting and performing extrusion foaming.

Further, Patent Document 2 describes that a low-density polystyrene foam is produced by using a physical foaming agent in which HFO1234ze and HFO1233zd are combined in a specific composition. In Examples, a 50 mm counter-rotating twin-screw extruder is described. It is described that the polystyrene foam having a cylindrical shape with an apparent density of 38 to 77 kg / m ³ was obtained by performing extrusion foaming using an orifice strand die (1 mm die land) having a diameter of 2 and 3 mm. .

  Further, in Patent Document 3, a hydrofluoroolefin such as HFO1234ze, a saturated hydrocarbon having a carbon number of 3 to 5 such as isobutane, and a physical foaming agent in which water and / or carbon dioxide are combined in a specific composition are used. It is described that a polystyrene-based resin extruded heat insulating plate is manufactured.

JP, 2015-17268, A Japanese Patent Publication No. 2015-522696 JP, 2013-194101, A

However, the polystyrene foam described in Patent Document 1 has a high apparent density of 70 to 100 kg / m ^{3 and} a small cross-sectional area. Further, the styrene foam is extruded into a rod shape and is not formed into a plate shape.
The polystyrene foam described in Patent Document 2 is extruded into a cylindrical shape, and is not extruded and then formed into a plate shape. Further, Patent Document 2 describes that the occurrence of surface defects cannot be prevented when the apparent density is 46 kg / m ³ or less.

The present inventors have attempted to produce a plate-shaped polystyrene resin extruded foam plate having a low apparent density and a plate shape, using the physical foaming agents described in Patent Documents 1 and 2.
However, in any combination, the foaming agent is separated from the expandable molten resin composition in the die, which causes a spot (surface defect) on the surface of the foam immediately after extrusion. Happened. Further, at the stage of shaping into a plate shape by a shaping device, there is a problem that molding into a foam plate is not stable and a good foam plate cannot be obtained.

  On the other hand, according to the production method described in Patent Document 3, a physical expansion agent containing hydrofluoroolefin is used as a physical expansion agent to produce a polystyrene-based resin extruded foam insulation plate with a low apparent density and a beautiful surface. Became possible. However, if the amount of hydrofluoroolefin added is increased in an attempt to further reduce the thermal conductivity of the obtained foam plate, it is possible to stably manufacture the foam plate when the cross-sectional area of the foam plate is small. However, when the cross-sectional area is large, foaming is not stable and the width of the foamed plate varies, leaving a problem in manufacturing stability.

As described above, in the prior art, when hydrofluoroolefin is used as a physical foaming agent, when the amount of hydrofluoroolefin added is large, the apparent density is 40 kg / m ³ or less and the large cross-sectional area of 100 cm ² or more is obtained. A polystyrene-based resin extruded foam plate could not be stably obtained.

  In view of the problems of the prior art, the present invention uses a physical foaming agent containing hydrofluoropropene to stably produce a polystyrene resin extruded foam plate having a large cross-sectional area with a low apparent density and a polystyrene resin. It is an object of the present invention to provide a method for producing a resin extruded foam plate.

According to the present invention, the following method for producing a polystyrene-based resin extruded foam plate and a polystyrene-based resin extruded foam plate are provided.
[1] An apparent density of 20 to 40 kg / m ³ , including a step of extruding and foaming a foamable molten resin composition obtained by kneading a polystyrene resin, a flame retardant and a physical foaming agent, and molding the composition into a plate with a molding tool. In the method for producing a polystyrene resin foam plate having a vertical cross-sectional area of 100 cm ² or more in the extrusion direction,
The physical blowing agent contains (A) a saturated hydrocarbon having 4 to 5 carbon atoms and (B) hydrofluoropropene,
The total addition amount of the physical foaming agent is 1.0 to 2.0 mol with respect to 1 kg of polystyrene resin,
(A) The addition amount of the saturated hydrocarbon having 4 to 5 carbon atoms is 0.1 to 0.7 mol per 1 kg of the polystyrene resin, and (B) the addition amount of hydrofluoropropene is 1 kg of the polystyrene resin. On the other hand, 0.3 to 0.6 mol,
The total addition amount of (A) saturated hydrocarbon having 4 to 5 carbon atoms and (B) hydrofluoropropene is 0.8 to 1.2 mol with respect to 1 kg of the polystyrene resin,
(B) Hydrofluoroolefin contains (B1) 1,3,3,3-tetrafluoropropene and (B2) 1-chloro-3,3,3-trifluoropropene,
The molar ratio (B1: B2) of (B1) 1,3,3,3-tetrafluoropropene and (B2) 1-chloro-3,3,3-trifluoropropene is 80:20 to 20:80. A method for producing a polystyrene-based resin extruded foam plate, comprising:
[2] (B1) 1,3,3,3-tetrafluoropropene is added in an amount of 0.25 mol or less with respect to 1 kg of polystyrene resin, and the polystyrene resin extruded foam plate described in the above 1 is characterized. Manufacturing method.
[3] The method for producing a polystyrene-based resin extruded foam plate according to 1 or 2, wherein (A) the saturated hydrocarbon having 4 to 5 carbon atoms contains 50 mol% or more of isobutane.
[4] The polystyrene resin extrusion according to any one of 1 to 3 above, wherein the physical blowing agent further contains ethanol and water, and the molar ratio of ethanol and water is 40:60 to 10:90. Method of manufacturing foam board.
[5] A polystyrene resin extruded foam plate containing a flame retardant and having an apparent density of 20 to 40 kg / m ³ and a vertical cross-sectional area of 100 cm ² or more in the extrusion direction,
The extruded foam plate contains (A) saturated hydrocarbon having 4 to 5 carbon atoms and (B) hydrofluoropropene,
The content of saturated hydrocarbons pressing starting Awaban in (A) 4 to 5 carbon atoms together are pressing the starting foam plate 1kg per 0.1~ 0.7mo l, the content of (B) hydrofluoropropenes It is 0.3 to 0.6 mol per 1 kg of the extruded foam plate, and the total of the content of (A) saturated hydrocarbon having 4 to 5 carbon atoms and (B) content of hydrofluoroolefin in the extruded foam plate. 0.8 to 1.2 mol per 1 kg of extruded foam plate,
(B) Hydrofluoropropene contains (B1) 1,3,3,3-tetrafluoropropene and (B2) 1-chloro-3,3,3-trifluoropropene, and (B1) 1,3,3 , 3-tetrafluoropropene and (B2) 1-chloro-3,3,3-trifluoropropene in a molar ratio (B1: B2) of 80:20 to 20:80, a polystyrene resin Extruded foam board.

  According to the method for producing a polystyrene resin extruded foam plate of the present invention, (B1) 1,3,3,3-tetrafluoropropene and (B2) 1-chloro-3,3,3 as (B) hydrofluoropropene. -By using a physical blowing agent in which trifluoropropene is used in a specific ratio in combination with a specific amount of (A) a saturated hydrocarbon having 4 to 5 carbon atoms, hydrofluoropropene is used as compared with the conventional one. It can be added in a large amount and can prevent the generation of spots and the deterioration of formability (shapeability) into a plate-like body, so it has a low apparent density, a large cross-sectional area, and thermal conductivity. It is possible to stably manufacture a foam plate having a low value. This is the case when only either (B1) 1,3,3,3-tetrafluoropropene or (B2) 1-chloro-3,3,3-trifluoropropene is combined with (A) saturated hydrocarbon. This is an effect that cannot be obtained.

Hereinafter, the method for producing the polystyrene resin extruded foam plate of the present invention will be described in detail.
In the method for producing a polystyrene-based resin extruded foam plate of the present invention, a polystyrene-based resin, a flame retardant and a physical foaming agent are supplied to an extruder and heated, melted, kneaded, and then a physical foaming agent is injected. Further kneading, the resulting expandable molten resin composition is extruded from a high-pressure extruder through a die to a low-pressure region to be foamed, and through a step of molding into a plate shape by a molding tool, a polystyrene resin foam plate is obtained. Manufactured.

  As described above, the present invention is a method for producing a foam plate, which includes a step of molding the extruded foam body into a plate shape. In the molding step, a shaping device composed of two upper and lower plates made of polytetrafluoroethylene resin or the like installed at the exit of the die in parallel or gradually expanding from the entrance to the exit (hereinafter, A molding tool such as a guider) or a molding roll is arranged, and the extruded foam composition is molded into a plate by passing through the molding tool.

  Next, the polystyrene resin, physical foaming agent, flame retardant, and other additives used in the method of the present invention will be described in order.

  The polystyrene resin used in the present invention is a polymer mainly composed of styrene, and not only a styrene homopolymer but also a copolymer of styrene and a vinyl monomer copolymerizable with styrene may be used. it can. Specifically, polystyrene (GPPS), styrene-acrylonitrile copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer , Styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-maleic anhydride copolymer and the like. Further, these polystyrene-based resins may be used as a mixture of two or more kinds. The polystyrene resin may contain a polyfunctional monomer unit component such as divinylbenzene or a hyperbranched macromonomer. Among these polystyrene resins, polystyrene (GPPS) is preferable from the viewpoint of foamability.

  The polystyrene resin contains a styrene component in an amount of 50 mol% or more, preferably 60 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more.

  The polystyrene resin may contain other polymers within the range in which the objects and effects of the present invention are achieved. Other polymers include polyethylene resins (one kind or a mixture of two or more kinds selected from the group of ethylene homopolymers and ethylene copolymers having an ethylene unit component content of 50 mol% or more), polypropylene. -Based resin (one kind or a mixture of two or more kinds selected from the group of propylene homopolymer and propylene-based copolymer having a propylene unit component content of 50 mol% or more), polyphenylene ether-based resin, polymethyl methacrylate Thermoplastic resin such as styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer hydrogenated product, styrene-isoprene-styrene block copolymer water Additives and thermoplastic elastomers such as styrene-ethylene copolymers are listed. It is. These other polymers are mixed according to the purpose so as to be less than 50% by weight in the polystyrene resin, preferably 30% by weight or less, more preferably 10% by weight or less. can do.

  Further, in order to improve the heat insulating property of the foam plate, a resin containing an amorphous polyethylene terephthalate copolymer can be used as the polystyrene resin. In this case, it is preferable that the amorphous polyethylene terephthalate copolymer is blended in the polystyrene resin in an amount of 5% by mass or more and less than 50% by mass.

From the viewpoint of foamability and moldability, it is preferable to use a polystyrene resin having a melt viscosity of about 500 to 2500 Pa · s, more preferably 600 to 2000 Pa · s, and further preferably 700 to 1500 Pa · s. s. The melt viscosity is a value measured under the conditions of a temperature of 200 ° C. and a shear rate of 100 sec ⁻¹ based on JIS K7199: 1999.

  The physical blowing agent used in the method of the present invention contains (A) a saturated hydrocarbon having 4 to 5 carbon atoms and (B) hydrofluoropropene.

  Examples of the saturated hydrocarbon having 4 to 5 carbon atoms (A) include n-butane, isobutane, cyclobutane, n-pentane, isopentane, neopentane, cyclopentane, etc. These saturated hydrocarbons may be used alone or Two or more kinds can be used in combination. Among these, isobutane and n-butane are preferable, and isobutane is particularly preferable, because a foamed plate having a low apparent density can be easily produced and a foamed plate excellent in heat insulation can be obtained.

  When using isobutane, the content of isobutane in the saturated hydrocarbon (A) is preferably 50 mol% or more, more preferably 60 mol% or more, even more preferably 70 mol% or more, particularly preferably 80 mol% or more, Most preferably, it is 90 mol% or more.

  (B) Hydrofluoropropene includes 1,3,3,3-tetrafluoropropene (HFO1234ze), 1-chloro-3,3,3-trifluoropropene (HFO1233zd), 2,3,3,3-tetra. Fluoropropene (HFO1234yf), 1,2,3,3,3-pentafluoropropene (HFO1225ye), 1,1,3,3,3-pentafluoropropene (HFO1225zc), 1,1,2,3,3- Pentafluoropropene (HFO1225yc) etc. are mentioned.

  The physical foaming agent in the method of the present invention contains (A) a saturated hydrocarbon having 4 to 5 carbon atoms and (B) hydrofluoropropene, and the total addition amount thereof is 1.0 to 1 kg of polystyrene resin. It is 2.0 mol. If the total amount added is too small, it may not be possible to obtain a desired foam plate having a low apparent density. On the other hand, if the amount is too large, stable extrusion foaming may not be possible. From this viewpoint, the lower limit of the total amount added is preferably 1.1 mol with respect to 1 kg of the polystyrene resin. On the other hand, the upper limit of the total amount added is preferably 1.8 mol, more preferably 1.6 mol, and even more preferably 1.5 mol with respect to 1 kg of polystyrene resin.

  (A) The addition amount of the saturated hydrocarbon having 4 to 5 carbon atoms is 0.7 mol or less with respect to 1 kg of the polystyrene resin. When the amount of the saturated hydrocarbon (A) added is too large, the resulting foamed plate is likely to burn, and even if a large amount of the flame retardant is added, it may not be possible to impart a high degree of flame retardancy to the foamed plate. From this viewpoint, the upper limit of the amount of the saturated hydrocarbon (A) added is preferably 0.6 mol with respect to 1 kg of the polystyrene resin. On the other hand, the lower limit thereof is preferably about 0.1 mol, more preferably about 0.2 mol, and even more preferably about 0.3 mol, from the viewpoint of foamability and heat insulation of the resulting foam plate.

  The addition amount of (B) hydrofluoropropene is 0.3 to 0.6 mol per 1 kg of the polystyrene resin. If the added amount is too large, it may not be possible to prevent the occurrence of the spots (surface defects), the moldability in the molding tool may be deteriorated, and the width of the extruded foam may be largely changed. On the other hand, if the addition amount is too small, it may not be possible to obtain a foam plate having low thermal conductivity. From this viewpoint, the upper limit of the addition amount of (B) hydrofluoropropene is preferably 0.5 mol with respect to 1 kg of the polystyrene resin. The lower limit is preferably 0.35 mol, and more preferably 0.4 mol with respect to 1 kg of polystyrene resin.

The total amount of (A) saturated hydrocarbon and (B) hydrofluoropropene added is 0.8 to 1.2 mol per 1 kg of the polystyrene resin. If the total amount added is too small, a foamed plate having the desired thermal conductivity may not be obtained. On the other hand, if the total amount added is too large, the formability into a plate-like body may be deteriorated, and a good foamed plate may not be obtained.
From this point of view, the upper limit of the total addition amount is preferably 1.1 mol, and more preferably 1.0 mol with respect to 1 kg of the polystyrene resin. The lower limit is preferably 0.9 mol with respect to 1 kg of polystyrene resin.

The (B) hydrofluoropropene used in the method of the present invention includes (B1) 1,3,3,3-tetrafluoropropene (HFO1234ze) and (B2) 1-chloro-3,3,3-trifluoropropene (HFO1233zd). ) And are included.
The (B) hydrofluoropropene is 90 mol% of (B1) 1,3,3,3-tetrafluoropropene (HFO1234ze) and (B2) 1-chloro-3,3,3-trifluoropropene (HFO1233zd). It is preferable to include the above.
In the method of the present invention, 1,3,3,3-tetrafluoropropene (HFO1234ze) is trans-1,3,3,3-tetrafluoropropene (trans HFO1234ze) and cis-1,3,3,3. 3-tetrafluoropropene (cis HFO1234ze) may be included or both alone, and 1-chloro-3,3,3-trifluoropropene (HFO1233zd) is trans-1-chloro-3,3,3. -Trifluoropropene (trans HFO1233zd) and / or cis-1-chloro-3,3,3-trifluoropropene (cis HFO1233zd) may be included.

  When both (B1) HFO1234ze and (B2) HFO1233zd are used in a specific ratio and in combination with a specific amount of (A) saturated hydrocarbon, either (B1) or (B2) alone (A) Even if the total addition amount of (B1) and (B2) is increased with respect to the addition amount of (B1) or (B2) when combined with a saturated hydrocarbon, generation of spots is suppressed and foaming extruded. Variations in body width are also suppressed.

  The molar ratio (B1: B2) of (B1) HFO1234ze and (B2) HFO1233zd is 80:20 to 20:80. When the mol ratio of (B1) and (B2) is out of the above range, the foamability may be deteriorated. Further, when the mol ratio of (B1) and (B2) is within the above range, a foam plate having a lower thermal conductivity can be obtained. From these viewpoints, the molar ratio is preferably 70:30 to 30:70.

  The addition amount of (B1) HFO1234ze is preferably 0.25 mol or less with respect to 1 kg of the polystyrene resin. When the added amount of (B1) is within this range, the foamed plate can be obtained particularly stably.

In the present invention, in order to obtain a foam plate having a desired apparent density, the physical foaming agent may contain a foaming agent other than (A) saturated hydrocarbon and (B) hydrofluoropropene.
Other foaming agents include methyl chloride, ethyl chloride, dimethyl ether, diethyl ether, ethyl methyl ether, methyl formate, ethyl formate, methanol, ethanol, water, carbon dioxide, nitrogen and the like. These other foaming agents may be used alone or in combination of two or more.

  Among the other foaming agents, one or more selected from ethanol, carbon dioxide, and water are preferable because they do not impair the flame retardancy of the foam plate and are environmentally friendly.

  Among these, a combination of ethanol and water is more preferable from the viewpoint of excellent foamability and easy production of a foam plate having a low apparent density. In that case, the molar ratio of ethanol to water is preferably 40:60 to 10:90.

  The flame retardant used in the present invention is preferably a brominated flame retardant. Examples of the brominated flame retardant include brominated butadiene-styrene copolymer, brominated bisphenol flame retardant, brominated isocyanurate flame retardant and the like. In the present invention, the brominated butadiene-styrene copolymer among them is more preferable. However, other brominated flame retardants can be used in combination with the brominated butadiene-styrene copolymer.

  The total amount of the brominated flame retardant added is preferably 0.5 to 10 parts by weight, more preferably 1 to 8 parts by weight, based on 100 parts by weight of polystyrene. Within this range, a foamed plate satisfying the flammability standard of the extruded polystyrene foam heat insulating plate described in JIS A9511: 2006R can be obtained without the flame retardant hindering the foaming property.

  The brominated butadiene-styrene copolymer is conventionally known, and for example, those disclosed in JP-A-2009-516019 and JP-A-2012-512942 can be used.

  A brominated butadiene-styrene block copolymer, which is a typical brominated butadiene-styrene copolymer, can be represented by the following general formula.

(In the formula, X, Y, and Z are positive integers.)

  Examples of the brominated butadiene-styrene block copolymer include commercial products such as Emerald Innovation 3000 from Chemtura and FR-122P from ICL-IP.

  In the production method of the present invention, a heat stabilizer and a flame retardant aid can be added to the polystyrene resin in addition to the flame retardant.

  Examples of the heat stabilizer include one or more heat stabilizers selected from epoxy compounds, phenol compounds, hindered amine compounds and phosphite compounds. The total content of the heat stabilizer is preferably 0.01 to 30 parts by mass with respect to 100 parts by mass of the flame retardant.

  Examples of the flame retardant aid include at least one flame retardant aid selected from diphenylalkane, diphenylalkene, and polyalkylbenzene. By blending these, the oxygen index of the obtained foam can be improved.

  Examples of the dipheenylalkane include 2,3-dimethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane, and , 4-diethyl-3,4-diphenylhexane. Examples of the diphenylalkene include 2,4-diphenyl-4-methyl-1-pentene and 2,4-diphenyl-4-ethyl-1-pentene. Examples of the polyalkylenebenzene include poly-1,4-diisopropylbenzene (CCPIB). Among these, poly-1,4-diisopropylbenzene (CCPIB) is preferable. The blending amount of the flame retardant aid is preferably 1 to 20 parts by mass, and more preferably 2 to 10 parts by mass with respect to 100 parts by mass of the flame retardant.

  In the production method of the present invention, a bubble regulator, a colorant, an antioxidant, a radiation suppressant, a filler, a lubricant and the like can be added to the polystyrene resin.

  Examples of the cell regulator include talc, kaolin, mica, silica, calcium carbonate, barium sulfate, titanium oxide, clay, aluminum oxide, bentonite, diatomaceous earth, and other inorganic substances. Further, two or more kinds of the cell regulator may be used in combination. The blending amount of the cell adjuster is preferably 0.01 to 7.5 parts by mass, and more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the polystyrene resin.

  Examples of the radiation suppressing agent include fine powdery ones having a radiation suppressing effect, and specifically, metal oxides such as titanium oxide, metals such as aluminum, carbon black, carbon such as graphite, ceramics and the like. Can be illustrated. These can be used alone or in combination of two or more. The radiation suppressor is used in an amount of 0.5 to 5 parts by weight, preferably 1 to 4 parts by weight, based on 100 parts by weight of the polystyrene resin.

Next, the physical properties of the foam plate obtained by the method of the present invention will be described.
The apparent density of the foam plate is 20 to 40 kg / m ³ . If the apparent density is too low, the mechanical strength such as compressive strength may be so low that it cannot be used as a heat insulating material. On the other hand, if the apparent density is too high, the lightness may be impaired, and it may be difficult to handle, or the heat insulating property may deteriorate. From this viewpoint, the apparent density is preferably 25 kg / m ³ or more and less than 38 kg / m ³ .

The foam plate according to the present invention has a vertical cross-sectional area of 100 cm ² or more, preferably 200 cm ² or more. The upper limit of its cross-sectional area is approximately 1500 cm ² .
In the present specification, the vertical cross-sectional area in the extrusion direction means the cross-sectional area of the vertical cross section orthogonal to the extrusion direction of the extruded foam plate.

  Usually, a foam plate is manufactured by making a base plate (foam) with a size larger than the desired size by one or more and cutting the base plate to adjust the width and length, and in some cases the thickness. To be done. Here, if the width of the original plate fluctuates greatly during manufacturing and the width becomes narrower than the specified value, a foamed plate of a specified size cannot be obtained, resulting in poor yield. Further, in the production of a foam plate, foaming tends to be more difficult as the apparent density is lower and the cross-sectional area is larger. According to the method for producing a polystyrene-based resin extruded foam board of the present invention, the appearance density is low when a foaming agent containing hydrofluoropropene is used as a physical foaming agent and a large cross-sectional area is produced. A good foam plate can be stably manufactured.

  When the foam plate according to the present invention is used as a heat insulating material, its thickness is preferably 10 to 150 mm, more preferably 15 mm to 120 mm.

  The width of the foam plate is preferably 800 mm or more, more preferably 900 mm or more. The upper limit is approximately 1200 mm.

  The average cell diameter in the thickness direction of the foam plate is preferably 0.05 to 1 mm, more preferably 0.06 to 0.5 mm, and further preferably 0 in view of the balance between the mechanical strength and the heat insulation performance of the foam plate. It is 0.07 to 0.2 mm.

The average cell diameter in this specification means the cell diameter obtained by the following measuring method.
The average cell diameter in the thickness direction of the foam plate (DT: mm) and the average cell diameter in the width direction of the foam plate (DW: mm) are the vertical cross-sectional area of the foam plate in the extrusion direction (vertical cross section orthogonal to the foam plate's extrusion direction). For each bubble present in, have four sides parallel to the thickness direction and the width direction, and measure the length of the side in the thickness direction of the rectangle circumscribing the bubble and the length of the side in the width direction, The bubble diameter in the thickness direction and the bubble diameter in the width direction of each bubble are calculated for each, and the arithmetic mean value of each is taken as the average bubble diameter in the thickness direction (DW) and the average bubble diameter in the width direction (DT).
On the other hand, the average bubble diameter (DL: mm) in the extrusion direction of the foam plate is present in a cross section perpendicular to the extrusion direction of the foam plate (a vertical cross section parallel to the extrusion direction of the foam plate and bisected at the center in the width direction). For each bubble, having four sides parallel to the thickness direction and the extrusion direction, and measuring the length of the side in the extrusion direction of the rectangle circumscribing the bubble, determine the bubble diameter in the thickness direction of each bubble, The arithmetic mean value thereof is taken as the average bubble diameter (DL) in the extrusion direction.
Further, the average cell diameter (DH: mm) in the horizontal direction of the foam plate is a geometric average value of DW and DL.

Furthermore, the foam deformation rate of the foam plate is preferably 0.7 to 2.0, more preferably 0.8 to 1.5, and further preferably 0.8 to 1.2. The cell strain rate is a value calculated by dividing the D _T obtained by the measuring method in _{D H (D T / D H} ), bubbles as bubble deformation ratio is less than 1 flat And the larger it is, the longer the portrait is. When the cell deformation rate is within the above range, the foam plate has excellent mechanical strength and further high heat insulation.

  The closed cell ratio of the foam plate is preferably 60% or more, more preferably 65% or more, further preferably 70% or more, particularly preferably 80% or more, and most preferably 90% or more. The higher the closed cell ratio, the longer the foaming agent such as isobutane can stay in the cells, and the high heat insulating performance can be maintained for a long time, and the foam plate has excellent mechanical strength.

The closed cell ratio: S (%) is measured using an air comparison type hydrometer 930 manufactured by Toshiba Beckman Co., Ltd. in accordance with the procedure C described in ASTM D2856-70 (1976 recertification). The actual volume of the test piece (the sum of the volume of the closed cells and the volume of the resin portion): Vx (cm ³ ) It can be calculated by the following formula (1).
S (%) = (Vx−W / ρ) × 100 / (Va−W / ρ) (1)
However, Va, W, and ρ in the above formula are as follows.
Va: Apparent volume (cm ³ ) of the test piece used for measurement
W: Mass of test piece (g)
ρ: Density (g / cm ³ ) of the resin composition constituting the test piece

In addition, the density ρ (g / cm ³ ) of the resin composition is obtained by performing an operation of defoaming the air bubbles of the test piece used for measurement and the test piece used for measurement by defoaming the air bubbles. It can be determined from the volume (cm ³ ) of the sample.

  The heat conductivity of the foam plate is preferably 0.020 to 0.028 W / m · K, more preferably 0.021 to 0.025 W / m · K. When the thermal conductivity of the foam plate is within this range, excellent heat insulation can be obtained. The thermal conductivity is measured based on the flat plate heat flow meter method (heat flow meter two-piece method, high temperature side 38 ° C, low temperature side 8 ° C, average temperature 23 ° C) described in JIS A1412-2 (1999). be able to.

  The extruded polystyrene resin foam plate of the present invention can be produced by the above-mentioned method of the present invention, and has a plate-like shape and contains the flame retardant.

Apparent density of the foam plate is 20~40kg / ^{m 3,} preferably less than 25 kg / ^{m 3} or more 38 kg / ^{m 3.}
The cross-sectional area perpendicular to the extrusion direction is 100 cm ² or more, and preferably 200 cm ² or more. The upper limit of its cross-sectional area is approximately 1500 cm ² .

  The foam plate contains (A) a saturated hydrocarbon having 4 to 5 carbon atoms and (B) hydrofluoropropene.

  The content of the (A) saturated hydrocarbon in the foam plate is 0.7 mol or less per 1 kg of the foam plate. If the content is too large, the flame retardancy may be impaired. From this viewpoint, the content is preferably 0.6 mol or less per 1 kg of the foam plate. On the other hand, if the content is too small, the desired heat insulating property may not be obtained. The lower limit of the content is preferably about 0.1 mol, more preferably 0.2 mol, further preferably 0.3 mol.

  The content of (B) hydrofluoropropene in the foam plate is 0.3 to 0.6 mol per 1 kg of the foam plate. If the content is too large, it may not be possible to prevent the generation of spots (surface defects) during production, the moldability may be deteriorated, and the width of the extruded foam may be largely changed. On the other hand, if the content is too small, the desired heat insulating property may not be maintained. From this viewpoint, the upper limit of the content of (B) hydrofluoropropene is preferably 0.5 mol per 1 kg of the foam plate. The lower limit is preferably 0.4 mol with respect to 1 kg of the foam plate.

The total content of the (A) saturated hydrocarbon content and the (B) hydrofluoropropene content in the foam plate is 0.8 to 1.2 mol per 1 kg of the foam plate.
If the total content is too small, the desired heat insulating property will not be exhibited. On the other hand, if the total content is too large, the total amount of these foaming agents to be compounded becomes large at the time of production, and a good foam plate cannot be obtained. From this viewpoint, the upper limit of the total content is preferably 1.1 mol, and more preferably 1.0 mol, per 1 kg of the foam plate. The lower limit is preferably 0.9 mol per 1 kg of the foam plate.

  The hydrofluoropropene (B) contains (B1) 1,3,3,3-tetrafluoropropene and (B2) 1-chloro-3,3,3-trifluoropropene.

  The molar ratio (B1: B2) of (B1) 1,3,3,3-tetrafluoropropene and (B2) 1-chloro-3,3,3-trifluoropropene is 80:20 to 20:80. , 70:30 to 30:70 is preferable.

  The content of (A) saturated hydrocarbon and the content of (B) hydrofluoropropene in the foam plate can be measured by an internal standard method using a gas chromatograph. Specifically, an appropriate amount of sample is cut out from the foam plate, put into a sample bottle with a lid containing an appropriate amount of toluene and an internal standard substance, and the lid is closed. ) A saturated hydrocarbon and (B) hydrofluoropropene dissolved in toluene is used as a measurement sample for gas chromatographic analysis to perform (A) saturated hydrocarbon content in the foam plate and (B) hydrofluoropropene. Calculate the content of.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the examples.

  A first extruder having an inner diameter of 150 mm and a second extruder having an inner diameter of 200 mm are connected in series, and a flat die having a resin discharge port (die lip) having a rectangular cross section with a gap of 1 mm and a width of 440 mm is a second extruder. An extruder is used which is connected to the outlet and is provided with a shaping device (interval 28 mm) composed of a pair of upper and lower plates made of polytetrafluoroethylene resin installed in parallel at the resin outlet of the flat die. I was there.

The following raw materials were used to manufacture the foam plate.
[Polystyrene resin]
Polystyrene: Weight average molecular weight Mw = 270,000, melt viscosity 1100 Pa · s (mixed resin of 50% by weight of polystyrene having a weight average molecular weight Mw of 320,000 and 50% by weight of polystyrene having a weight average molecular weight Mw of 200,000)
The melt viscosity is a value measured by using a flow characteristic measuring machine of Capillograph 1D (manufactured by Toyo Seiki Seisakusho Co., Ltd.) under conditions of a temperature of 200 ° C. and a shear rate of 100 sec ⁻¹ .

[Flame retardants]
Brominated butadiene-styrene block copolymer (manufactured by ICL-IP, product name "FR-122P") and tris (2,3-dibromopropyl) isocyanurate (manufactured by Suzuyu Chemical Co., Ltd., product name "FCP-660"); Weight ratio 60:40

[Physical foaming agent]
(A) Saturated hydrocarbon: isobutane (manufactured by Mitsui Chemicals)
(B1) 1,3,3,3-tetrafluoropropene (HFO1234ze): (manufactured by Honeywell, product name “Solstice 1234ze (E)”)
(B2) 1-chloro-3,3,3-trifluoropropene (HFO1233zd): (manufactured by Honeywell, product name "Solstice 1233zd (E)")
Other foaming agents: water, ethanol

[Additive]
Bubble control agent: talc (Matsumura Sangyo, product name "High Filler # 12")
Heat stabilizer: Novolac type epoxy compound (manufactured by DIC, product name "EPICLON N680") 50% by mass, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-diphosphite (manufactured by ADEKA, product name "PEP36") 45 mass%, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (manufactured by BASF, product name "Irganox 1076") 5 mass%
Flame retardant aid: Poly-1,4-diisopropylbenzene (manufactured by UNITED INITIATORS, product name "CCPIB")

Examples 1-4, Comparative Examples 1-4
Polystyrene resin, flame retardant, flame retardant aid, heat stabilizer and bubble control agent were fed to the first extruder and heated to 200 ° C. and kneaded so that the blending amount and blending amount shown in Table 1 were obtained. As a molten resin composition, a physical foaming agent having the composition and amount shown in Table 1 was supplied to the molten resin composition through a foaming agent injection port provided at the tip of the first extruder, and further kneaded. The resulting foaming agent-containing molten resin composition was transferred to the second extruder, and the resin temperature was measured as shown in the same table as the foamed resin temperature (of the molten resin composition measured at the position of the joint between the extruder and the die). Temperature)) to obtain a foamable molten resin composition, and then the foamable molten resin composition is extruded from the die lip into the guider at a discharge rate of 800 kg / hr to form a foam (original plate), which is passed through the guider. While molding (forming) into a plate shape, and further adjusting the thickness, width and length by cutting, a rectangular parallelepiped polystyrene resin extruded foam plate (width: 910 mm, length: 1820 mm, thickness: 25 mm, A cross-sectional area in the extrusion direction: 227.5 cm ² ) was obtained. Immediately after the production, the foam plate was transferred to a constant temperature and humidity chamber at 23 ° C. and a relative humidity of 50%, and the foam plate was allowed to stand in the constant temperature and humidity chamber.

  About the obtained foamed plates of Examples 1 to 4 and Comparative Examples 1 to 4, after 7 days of production, the apparent density, thickness, cross-sectional area, closed cell ratio, foaming agent content, and thermal conductivity were measured by the following methods. The flame retardancy, appearance (surface property and spot), and manufacturing stability were evaluated according to the following criteria. The results are shown in Table 1.

(Apparent density)
50 mm × 50 mm × thickness: A rectangular parallelepiped sample having a thickness of the foam plate is cut out from each of the center and both ends in the width direction of the foam plate, the weight is measured, and the weight of each sample is divided by the volume. The apparent density was obtained, and the arithmetic mean value thereof was used as the apparent density of the foam plate.

(Thickness)
The thickness of the central portion and both end portions in the width direction of the cross section perpendicular to the extrusion direction of the foam plate was read with a caliper, and the value obtained by arithmetically averaging the measured values was taken as the thickness of the foam plate.

(Cross section area)
The cross-sectional area of the cross section perpendicular to the extrusion direction was obtained as the product of the thickness of the foam plate and the width of the foam plate. The width of the foam plate was calculated as the arithmetic mean value of the widths of five locations randomly selected from the foam plate.

(Closed cell rate)
A rectangular parallelepiped sample each having a size of 25 mm × 40 mm × 20 mm is cut out from the center of the foam plate in the width direction, the closed cell rate of each sample is measured by the procedure C of ASTM-D2856-70, and their arithmetic mean value is calculated. Was defined as the closed cell rate of the foam plate.

(Foaming agent content)
Approximately 1 g of a test piece for measurement was cut out from the center of the foam plate and subjected to gas chromatographic analysis (internal standard method) to determine the content of (A) saturated hydrocarbon and (B) hydrofluoropropene in the foam plate. The amount was calculated.
<Measurement conditions for gas chromatograph analysis>
Column: manufactured by Shinwa Kako Co., Ltd. Carrier: chromsorb W, 60-80 mesh, AW-DMCS treated product Liquid phase: Silicone DC550 (liquid phase amount 20%)
Column dimensions: column length 4.1 m, column inner diameter 3.2 mm
Column material: glass Column temperature: 40 ° C
Inlet temperature: 200 ℃
Carrier gas: Nitrogen Carrier gas velocity: 50 ml / min
Detector: FID
Detector temperature: 200 ℃

(Thermal conductivity)
200 mm in length × 200 mm in width × thickness: A rectangular parallelepiped test piece having a thickness of the foam board is cut out from the vicinity of the center of the foam plate, and the flat plate heat flow meter method (heat flow meter 2 Thermal conductivity was measured based on the single-wafer method, high temperature side 38 ° C., low temperature side 8 ° C., average temperature 23 ° C.).

(Flame retardance)
Those that satisfy the flammability standard of the extruded polystyrene foam heat insulating plate described in JIS A9511 (2006R) were evaluated as “◯”, and those that did not satisfy were evaluated as “x”.

(appearance)
The surface condition of the foam plate was visually evaluated according to the following criteria.
◯: No spot is observed and the surface is smooth. ×: Spot is generated and the surface is not smooth.

(Manufacturing stability)
The width of the original plate was measured during the production of the foamed plate, and evaluated according to the following criteria.
◎: Variation of width of raw material (maximum value-minimum value) is within 25 mm ○: Variation of width of raw material (maximum value-minimum value) exceeds 25 mm and 30 mm or less ×: The fluctuation (maximum value-minimum value) may exceed 30 mm and fall below the specified width (910 mm).

Claims (5)

An apparent density of 20 to 40 kg / m ³ , including a step of extruding and foaming an expandable molten resin composition obtained by kneading a polystyrene-based resin, a flame retardant and a physical foaming agent to form a plate shape with a molding tool, vertical direction of extrusion In the method for producing a polystyrene resin extruded foam plate having a cross-sectional area of 100 cm ² or more,
The physical blowing agent contains (A) a saturated hydrocarbon having 4 to 5 carbon atoms and (B) hydrofluoropropene,
The total addition amount of the physical foaming agent is 1.0 to 2.0 mol with respect to 1 kg of polystyrene resin,
(A) The addition amount of the saturated hydrocarbon having 4 to 5 carbon atoms is 0.1 to 0.7 mol per 1 kg of the polystyrene resin, and (B) the addition amount of hydrofluoropropene is 1 kg of the polystyrene resin. On the other hand, 0.3 to 0.6 mol,
The total addition amount of (A) saturated hydrocarbon having 4 to 5 carbon atoms and (B) hydrofluoropropene is 0.8 to 1.2 mol with respect to 1 kg of the polystyrene resin,
(B) Hydrofluoropropene includes (B1) 1,3,3,3-tetrafluoropropene and (B2) 1-chloro-3,3,3-trifluoropropene,
The molar ratio (B1: B2) of (B1) 1,3,3,3-tetrafluoropropene and (B2) 1-chloro-3,3,3-trifluoropropene is 80:20 to 20:80. A method for producing a polystyrene-based resin extruded foam plate, comprising:
(B1) The amount of 1,3,3,3-tetrafluoropropene added is 0.25 mol or less with respect to 1 kg of the polystyrene resin, and the production of the polystyrene resin extruded foam plate according to claim 1. Method.
The method for producing a polystyrene-based resin extruded foam plate according to claim 1 or 2, wherein (A) the saturated hydrocarbon having 4 to 5 carbon atoms contains 50 mol% or more of isobutane.
The polystyrene foam extruded foam plate according to any one of claims 1 to 3, wherein the physical foaming agent further contains ethanol and water, and the molar ratio of ethanol and water is 40:60 to 10:90. Manufacturing method.
In a polystyrene resin extruded foam plate containing a flame retardant and having an apparent density of 20 to 40 kg / m ³ and a vertical cross-sectional area of 100 cm ² or more in the extrusion direction,
The extruded foam plate contains (A) saturated hydrocarbon having 4 to 5 carbon atoms and (B) hydrofluoropropene,
The content of saturated hydrocarbons pressing starting Awaban in (A) 4 to 5 carbon atoms together are pressing the starting foam plate 1kg per 0.1~ 0.7mo l, the content of (B) hydrofluoropropenes It is 0.3 to 0.6 mol per 1 kg of the extruded foam plate, and the total of the content of (A) saturated hydrocarbon having 4 to 5 carbon atoms and (B) content of hydrofluoroolefin in the extruded foam plate. 0.8 to 1.2 mol per 1 kg of extruded foam plate,
(B) Hydrofluoropropene contains (B1) 1,3,3,3-tetrafluoropropene and (B2) 1-chloro-3,3,3-trifluoropropene, and (B1) 1,3,3 , 3-tetrafluoropropene and (B2) 1-chloro-3,3,3-trifluoropropene in a molar ratio (B1: B2) of 80:20 to 20:80, a polystyrene resin Extruded foam board.