JP2016138291A - Manufacturing method of polystyrene resin extrusion foaming heat insulation plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a polystyrene resin extrusion foaming heat insulation plate small in heat conductivity, excellent in heat insulation for long term, good in high thickness, high foaming ratio and appearance by using a physical foaming agent having a zero or extremely low ozone layer depletion coefficient and a small global warming coefficient.SOLUTION: In a method of manufacturing an extrusion foaming heat insulation plate having thickness of 10 to 150 mm, apparent density of 20 kg/mor more and less than 40 kg/mand isolated cell rate of 80% or more for extrusion foaming a foamable resin molten article containing a substrate resin mainly containing a polystyrene resin, a physical foaming agent and a fire retardant, 3 to 50 mol% of hydrofluoro-olefin, 30 to 70 mol% of saturated hydrocarbon having 3 to 5 carbon atoms, 15 to 50 mol% or water and/or carbon dioxide are used as the physical foaming agent, where the total amount of blending ratio for the hydrofluoro-olefin, the saturated hydrocarbon having 3 to 5 carbon atoms and the water and/or carbon dioxide is 100 mol%, the saturated hydrocarbon having 3 to 5 carbon atoms is n-butane and/or isobutane and average cell deformation rate of the extrusion foaming heat insulation sheet is 0.7 to 2.0.SELECTED DRAWING: None

Description

  The present invention provides a method for producing a polystyrene-based resin extruded foam insulation board having a low thermal conductivity, excellent heat insulation over a long period of time, high flame retardancy, and excellent appearance (hereinafter referred to as “extruded foam insulation board”). Or a simple foam insulation board), a method for producing a polystyrene-based resin extruded foam insulation board useful as a heat insulation material for building walls, floors, roofs and the like is provided.

  Since the polystyrene-based resin extruded foam heat insulating plate has excellent heat insulating properties and mechanical strength, those formed into a plate shape are widely used as heat insulating materials and the like. Such a foam insulation board is generally provided by kneading a physical foaming agent into a melt obtained by heating and melting a polystyrene resin in an extruder, and the resulting foamable melt-kneaded product is attached to the tip of the extruder. Manufactured by extrusion foaming from a flat die or the like to a low pressure region.

  Conventionally, chlorofluorocarbons (hereinafter referred to as CFC) such as dichlorodifluoromethane have been widely used as physical foaming agents used in the production of the polystyrene resin extruded foam insulation board as described above. Has a high risk of destroying the ozone layer, hydrogen atom-containing fluorinated fluorinated hydrocarbons (hereinafter referred to as HCFC) having a small ozone depletion coefficient have been used instead of CFCs. However, HCFC does not have no danger of destroying the ozone layer because the ozone layer depletion coefficient is not 0 (zero). In recent years, it has been studied to use a fluorinated hydrocarbon (hereinafter referred to as HFC) having a ozone depletion coefficient of 0 (zero) and having no chlorine atom in the molecule as a foaming agent.

  However, although HFC is preferable in that it does not have an ozone layer depletion coefficient, there is still room for improvement from the viewpoint of protecting the global environment because the global warming coefficient is large.

  For this reason, various eco-friendly foaming agents having an ozone depletion coefficient of 0 (zero) and a low global warming potential have been studied. In recent years, both fluorinated olefins (hydrofluoroolefins, hereinafter referred to as HFOs) have been studied. Is proposed as an alternative to HFC in Patent Document 1.

Special table 2010-522808 gazette

  However, in Patent Document 1, when HFO is used as a foaming agent and a base resin mainly composed of a polystyrene-based resin is extruded and foamed, the foam insulation is thick and has a high closed cell ratio and excellent appearance. There was still a problem with respect to obtaining a foam, especially a foam insulation board having high thermal insulation properties with excellent long-term insulation properties.

  In the production of a polystyrene resin extruded foam insulation board, the present invention uses a physical foaming agent having a zero or very low ozone layer depletion coefficient and a small global warming coefficient, and has a low thermal conductivity and a long-term heat insulation property. Another object of the present invention is to provide a method for producing a polystyrene-based resin-extruded foam insulation board having excellent flame retardancy, high thickness, high expansion ratio, and good appearance.

The gist of the present invention is the following (1) to (3).
(1) A foamable resin melt containing a base resin mainly composed of a polystyrene-based resin, a physical foaming agent, and a flame retardant is extruded and foamed, and has a thickness of 10 to 150 mm and an apparent density of 20 kg / m ^{3 to} 40 kg / m ³ and a method for producing an extruded foam insulation board having a closed cell ratio of 80% or more, wherein the physical foaming agent is 3 to 50 mol% hydrofluoroolefin and 30 to 70 mol% carbon number 3 to 3. 5 saturated hydrocarbons, 15-50 mol% water and / or carbon dioxide (however, the hydrofluoroolefin, the saturated hydrocarbons having 3 to 5 carbon atoms, and the water and / or carbon dioxide content) The saturated hydrocarbon having 3 to 5 carbon atoms is n-butane and / or isobutane, and the average foam deformation rate of the extruded foam insulation board is 0.7 to Method for producing extruded polystyrene resin foam of which is a .0.
(2) The total amount of the hydrofluoroolefin and the saturated hydrocarbon having 3 to 5 carbon atoms is 0.4 to 2 mol per kg of the base resin, and the amount of the water and / or carbon dioxide is The total is 0.05 to 0.6 mol per kg of the base resin, The method for producing a polystyrene-based resin extruded foam heat insulating plate according to the above (1).
(3) The method for producing a polystyrene-based resin extruded foam heat insulating plate according to (1) or (2), wherein the hydrofluoroolefin is tetrafluoropropene.

  In the production method of the present invention, in producing a polystyrene-based resin extruded foam insulation board, hydrofluoroolefin (HFO), a saturated hydrocarbon having 3 to 5 carbon atoms, water and / or carbon dioxide are used as a physical foaming agent. And by extrusion foaming using a mixed foaming agent that is blended at a specific blending ratio, extrusion foaming moldability is good, high foaming ratio, high thickness, long-term heat insulation and flame retardancy It is possible to obtain a polystyrene-based resin-extruded foam insulation board having excellent properties and good appearance. Since the obtained foam insulation board has a high closed cell ratio, HFO used as a foaming agent is difficult to dissipate from the foam and is excellent in long-term insulation. Further, even if HFO having relatively low solubility in polystyrene resin is used as the HFO, the HFO is uniformly mixed in the base resin by using a mixed foaming agent having a mixing ratio as described above. A high-thickness foam insulation board having a high expansion ratio and good appearance can be obtained.

  Below, the manufacturing method of the polystyrene-type resin extrusion foam insulation board of this invention is demonstrated.

  The method for producing a polystyrene resin extruded foam insulation board according to the present invention is an extrusion foam insulation that extrudes and foams a foamable resin melt containing a base resin, a physical foaming agent, and a flame retardant comprising a polystyrene resin as a main component. A method of manufacturing a plate, wherein HFO is used as a foaming agent having an ozone layer depletion coefficient of zero (0) or extremely low, a low global warming coefficient, and a saturated hydrocarbon having 3 to 5 carbon atoms, water and / or Alternatively, extrusion foaming is performed by using a mixed foaming agent containing carbon dioxide.

  As said physical foaming agent, 3-50 mol% HFO, 30-70 mol% C3-C5 saturated hydrocarbon, 5-50 mol% water and / or carbon dioxide (however, said HFO and , A total physical blending ratio of saturated hydrocarbons having 3 to 5 carbon atoms and water and / or carbon dioxide is 100 mol%).

(I) Physical foaming agent In the manufacturing method of this invention, as a physical foaming agent (C), HFO (C1) excellent in the effect which reduces the heat conductivity of a polystyrene-type resin extrusion foaming heat insulation board is a component of a physical foaming agent. In addition, a saturated hydrocarbon having 3 to 5 carbon atoms (C2) and water and / or carbon dioxide (C3) are used in combination. In particular, it is important to use a combination and a blending ratio of these foaming agents at a specific ratio described later in order to achieve the intended object of the present invention.

Specific examples of the hydrofluoroolefin (HFO) (C1) include trans-1,3,3,3-tetrafluoropropene (trans HFO-1234ze), cis-1,3,3,3-tetrafluoro. Examples include propene (cis HFO-1234ze) and 2,3,3,3-tetrafluoropropene (HFO-1234yf). These foaming agents can be used alone or in combination of two or more.
The above-mentioned HFO has an ozone depletion coefficient of zero or extremely small, has a very low global warming coefficient, and has a low thermal conductivity in a gaseous state and has a property of being difficult to burn. Therefore, by using the HFO as a physical foaming agent, it is possible to reduce the risk of ignition due to static electricity during production. In addition, since it is relatively easy to make the resulting foam insulation board flame-retardant, it is possible to reduce the amount of flame retardant added, reduce the influence of the flame retardant during extrusion foaming, and improve foam moldability It becomes possible to make it.

  In addition, as a foaming agent, the solubility with respect to a polystyrene-type resin is comparatively high, and HFO with high compatibility with a polystyrene-type resin, ie, although it is easy to dissipate from a foam in HFO, it can be added to a polystyrene-type resin much, HFO excellent in foaming ability as a foaming agent was preferably used, and an extruded foam having a high foaming ratio was obtained.

  On the other hand, when tetrafluoropropene (1234ze, 1234yf), which is HFO having low solubility in polystyrene resin and low compatibility with polystyrene resin, is used as a foaming agent, a foam insulation board with a high expansion ratio is used. When a large amount of tetrafluoropropene is added to obtain tetrafluoropropene from the resin melt at the time of extrusion foaming, there are places where the surface of the foam insulation board is greatly recessed (hereinafter referred to as spot holes). It may occur and the appearance of the heat insulating plate may be deteriorated. Moreover, when manufacturing a high-thickness foam heat insulating board, there existed a possibility that a closed-cell ratio may fall and long-term heat insulation may fall. In particular, in the present invention, even when HFO having a relatively low solubility in polystyrene resin is used, by using a specific mixed physical foaming agent, a foam insulation board having a high expansion ratio can be obtained. Furthermore, it is possible to obtain a polystyrene-based resin foam heat insulating plate with excellent long-term heat insulation and good appearance.

  In the mixed foaming agent of the present invention, the blending ratio of the HFO (C1) is 3 to 50 mol%, where the total of the foaming agents (C1), (C2) and (C3) is 100 mol%. When the blending ratio of HFO is low, the effect of improving heat insulation by HFO cannot be expected. On the other hand, when the blending ratio of the HFO exceeds the above range, the HFO is separated from the resin melt at the time of extrusion foaming, spot holes are generated on the surface of the foam heat insulating plate, or the closed cell ratio is reduced. There is a fear. From the above viewpoint, the blending ratio of the HFO is preferably 5 to 45 mol%, and more preferably 10 to 40 mol%.

  Moreover, it is preferable that the compounding quantity of the said HFO (C1) is 0.05-0.7 mol / kg per 1 kg of said base resin. If it is in the said range, an effective quantity of HFO will remain in the bubble of the foam heat insulation board after extrusion foaming, and the extrusion foam heat insulation board which has long-term heat insulation can be obtained. From the above viewpoint, the blending amount of the HFO is more preferably 0.1 to 0.6 mol / kg.

  Examples of the saturated hydrocarbon having 3 to 5 carbon atoms (C2) include propane having 3 carbon atoms, n-butane having 4 carbon atoms, isobutane (2-methylpropane), n-pentane having 5 carbon atoms, and isopentane (2- Methylbutane), neopentane (2,2-dimethylpropane), cyclopentane and the like. Moreover, these foaming agents can be used alone or in combination of two or more. Of these, n-butane and isobutane having 4 carbon atoms are preferred, and isobutane is more preferred.

  Since the saturated hydrocarbon (C2) having 3 to 5 carbon atoms has a lower permeation rate with respect to polystyrene resin than air and has a lower thermal conductivity than air, the obtained extruded foam insulation board has good heat insulation. It becomes. In addition, the saturated hydrocarbon having 3 to 5 carbon atoms is highly soluble in polystyrene resin and plasticizes the polystyrene resin, so that the melt viscoelasticity of the foamable resin melt is adjusted to a favorable range for foaming, It becomes possible to obtain an extruded foam heat insulating board having a high expansion ratio relatively easily. Further, even when HFO having relatively low compatibility with polystyrene resin is used as a component of the mixed foaming agent, the use of the saturated hydrocarbon having 3 to 5 carbon atoms compensates for a decrease in foaming ability. Therefore, it is possible to obtain a foam heat insulating plate having a high expansion ratio and having a long-term heat insulating property and having a good appearance.

  The blending ratio of the saturated hydrocarbon having 3 to 5 carbon atoms is 30 to 70 mol%, where the total of the blowing agents (C1), (C2), and (C3) is 100 mol%. If the blending ratio is too small, plasticization of the foamable resin melt is insufficient, and the extrusion foaming stability may be lowered, or the surface property of the foam insulation board may be lowered. On the other hand, if the blending ratio is too large, the flame retardancy of the foam insulation board may decrease, or the risk of ignition due to static electricity may increase during the production of the foam insulation board. From this point of view, the blending ratio of the saturated hydrocarbon having 3 to 5 carbon atoms is preferably 35 to 60 mol%, preferably 40 to 55 mol%, where the total of (C1) to (C3) of the physical foaming agent is 100 mol%. Is more preferable.

  Moreover, it is preferable that the compounding quantity of the said C3-C5 saturated hydrocarbon is 0.05 mol-0.8 mol per kg of said base resin. If it is in the said range, the extrusion foam heat insulating board with a favorable external appearance which has long-term heat insulation can be manufactured, without inhibiting the flame retardance of the foam heat insulating board after extrusion foaming. From the above viewpoint, the blending amount of the saturated hydrocarbon having 3 to 5 carbon atoms is more preferably 0.1 to 0.7 mol per 1 kg of the base resin.

  Moreover, in the manufacturing method of this invention, 5-50 mol% of water and / or carbon dioxide (C3) is mix | blended as a physical foaming agent. The water and / or carbon dioxide can have a high expansion ratio without impairing the flame retardancy of the extruded foam insulation board obtained as an inorganic physical foaming agent, and has high gas permeability to polystyrene resins. Since it dissipates early from an extruded foam heat insulating board, it becomes possible to stabilize the dimensional stability, heat insulation performance, and flame retardance performance of a foam heat insulating board at an early stage.

  When the mixing ratio of the water and / or carbon dioxide is too small, the effect of improving the expansion ratio may not be obtained. On the other hand, when the blending ratio of water and / or carbon dioxide is too large, the compatibility between water and / or carbon dioxide and the polystyrene resin of the base resin is relatively low. Water and / or carbon dioxide may be separated from the surface, and irregularities (spot holes) may be formed on the surface of the obtained extruded foam insulation board. From this viewpoint, the mixing ratio of water and / or carbon dioxide is preferably 10 to 45 mol%, more preferably 15 to 40 mol%, with the total of (C1) to (C3) of the physical foaming agent as 100 mol%. .

  Moreover, the compounding quantity of water and / or carbon dioxide is preferably 0.05 to 0.60 mol, more preferably 0.1 to 0.55 mol, per 1 kg of the base resin. If it is in the said range, compatibility with base-material resin is also favorable, and a foam heat insulating board with a favorable external appearance is obtained.

  Among these, water is preferable because the molecular weight is small and the foaming efficiency is high, so that the apparent density of the extruded foam insulation board can be further reduced. Moreover, since it becomes possible to expand a foamed resin temperature, it is preferable also from a viewpoint of extrusion foaming moldability improving.

  By extruding and foaming the above physical foaming agents (C1) to (C3) using the mixed physical foaming agents blended in the above-mentioned specific blending ratio, the long-term heat insulation with high thickness and high foaming ratio can be obtained. A foam heat insulating board having a good appearance can be easily obtained. The (C1) can particularly improve long-term heat insulation, the (C2) plasticizes the base resin to particularly improve the extrusion foamability, and the (C3) increases the expansion ratio and is obtained. By maintaining the dimensional stability of the foam insulation board to be produced, it becomes possible to obtain a good foam insulation board in correlation with the blending ratios of (C1) to (C3). From the above viewpoint, the total amount of the hydrofluoroolefin and the saturated hydrocarbon having 3 to 5 carbon atoms is preferably 0.4 to 2 mol per kg of the base resin, and 0.5 to 2 mol. More preferably, it is more preferably 0.7 to 2 mol. In addition, the said physical foaming agent does not necessarily need to mix | blend said (C1)-(C3) simultaneously, and should just be a state with which said (C1)-(C3) was mix | blended with the melt-kneaded material at the time of extrusion foaming. .

The thermal conductivity (A) of the polystyrene-based resin-extruded foam insulation board after 100 days from manufacture is desirably 0.0290 W / (m · K) or less, preferably 0.0280 W / (m · K) or less. More preferably it is. In the foam insulation board obtained by the production method of the present invention, a foam insulation board having a high closed cell ratio is obtained, and dissipation of the HFO from the foam board is effectively prevented. Even so, the thermal conductivity is kept low.
Moreover, in the foam heat insulating board obtained by the manufacturing method of the present invention, since the closed cell rate is particularly high, the thermal conductivity is kept low even if the thermal conductivity (B) after 200 days has passed after the manufacturing. It has excellent long-term heat insulation.
In addition, from the viewpoint of the long-term heat insulating property, the thermal conductivity (B) after 200 days after production / the thermal conductivity (A) (B / A) after 100 days after production may be less than 1.04. Preferably, it is 1.03 or less. In addition, since it is preferable that thermal conductivity does not increase in long-term heat insulation, the lower limit of the ratio (B / A) is approximately 1.00.

  Examples of foaming agents other than the above mixed physical foaming agents that can be added within the range not impairing the intended effect of the present invention include alkyl chlorides, alcohols, ethers, ketones, esters, and the like. . Among these blowing agents, alkyl chlorides having 1 to 3 carbon atoms, aliphatic alcohols having 1 to 4 carbon atoms, ethers having 1 to 3 carbon atoms in the alkyl chain, and esters such as methyl formate are suitable as the blowing agents. It is a thing. Examples of the alkyl chloride having 1 to 3 carbon atoms include methyl chloride and ethyl chloride. Examples of the aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, propyl alcohol, isopropyl alcohol, butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, aryl alcohol, crotyl alcohol, propargyl alcohol and the like. . Examples of the ether having 1 to 3 carbon atoms in the alkyl chain include dimethyl ether, ethyl methyl ether, diethyl ether, and methylene dimethyl ether. In particular, methyl chloride, dimethyl ether, methanol, and ethanol can be cited as those that can be expected to increase the expansion ratio. These foaming agents can be added singly or in combination of two or more in addition to the specific mixed physical foaming agent.

The amount of the foaming agent added to the base resin is appropriately selected in relation to the desired foaming ratio, but in order to obtain a foam heat insulating board having an apparent density of 20 to 50 kg / cm ³ , the base resin is usually 1 kg. In general, 0.4 to 3 mol is added as a total amount of the foaming agent, and preferably 0.5 to 2.5 mol is added.

(II) Base resin The base resin of the extruded foam heat insulating plate of the present invention contains a polystyrene resin as a main component. In this specification, a main component means what contains 50 weight% or more of polystyrene-type resin in base-material resin, More preferably, it is what contains 70 weight% or more, More preferably, it contains 80 weight% or more.

(I) Polystyrene resin As the polystyrene resin used in the present invention, for example, a styrene homopolymer, a styrene-acrylate copolymer having styrene as a main component, a styrene-methacrylate copolymer, styrene -Acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-maleic anhydride copolymer, styrene-polyphenylene ether copolymer, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene- Styrene copolymer, acrylonitrile-styrene-acrylic acid copolymer, styrene-methylstyrene copolymer, styrene-dimethylstyrene copolymer, styrene-ethylstyrene copolymer, styrene-diethylstyrene copolymer, high impact polystyrene When a copolymer such as len (HIPS) is used, the styrene component content in the polystyrene resin is preferably 70 mol% or more, more preferably 90 mol% or more. Among the polystyrene resins, a styrene homopolymer is most preferable from the viewpoint of having good thermal conductivity as a foam heat insulating board.

The polystyrene resin used in the present invention has a melt viscosity (η) of 500 to 10000 Pa · s, more preferably 700 to 8000 Pa · s, particularly 1000 to 6000 Pa · s under conditions of a temperature of 200 ° C. and a shear rate of 100 sec ^−1. Is preferred. When the melt viscosity (η) of the polystyrene-based resin is within the above range, the extrusion moldability of the foamable resin melt containing the mixed physical foaming agent is improved, and an extruded foam insulation board having a high foaming ratio is easy. Can be obtained.

(Ii) Other resins Other resins other than the polystyrene-based resin can be blended with the base resin within a range that does not impair the object effects of the present invention. Examples of the other resins include polyester resins, polyethylene resins, polypropylene resins, styrene-butadiene-styrene block copolymers, and hydrogenated products thereof, styrene-isoprene-styrene block copolymers, and hydrogenated products thereof. Products, styrene-ethylene copolymers, acrylonitrile-alkyl acrylate-butadiene copolymers, polymethyl methacrylate and the like. In addition, these resin can also be mix | blended individually or in combination of 2 or more types.
The compounding quantity of these resin is less than 50 weight% in base-material resin, More preferably, it is 30 weight% or less.

(III) Flame Retardant As a flame retardant that can be used in the production of the polystyrene resin extruded foam insulation board of the present invention, a brominated flame retardant is preferably used. Examples of brominated flame retardants include tetrabromobisphenol A, tetrabromobisphenol A-bis (2,3-dibromopropyl ether), tetrabromobisphenol A-bis (2-bromoethyl ether), and tetrabromobisphenol A-bis. (Allyl ether), tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) (= 2,2-bis [4- (2,3-dibromo-2-methylpropoxy) -3, 5-dibromophenyl] propane), tetrabromobisphenol S, tetrabromobisphenol S-bis (2,3-dibromopropyl ether), hexabromocyclododecane, tetrabromocyclooctane, tris (2,3-dibromopropyl) isocyanurate , Tribromopheno , Decabromodiphenyl oxide, tris (tribromoneopentyl) phosphate, N-2,3-dibromopropyl-4,5-dibromohexahydrophthalimide, brominated polystyrene, brominated bisphenol ether derivatives, SBS block polymers, etc. . These compounds can be used alone or in admixture of two or more. Among the above brominated flame retardants, hexabromocyclododecane, tetrabromocyclooctane, tetrabromobisphenol A-bis (2,3-dibromopropyl ether) because of its high thermal stability and high flame retardant effect. ), Tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether), and tris (2,3-dibromopropyl) isocyanurate are particularly preferred. In addition, these flame retardants can also be mix | blended individually or in combination of 2 or more types.

  In addition, it is particularly preferable in terms of thermal stability to use a composite flame retardant of a brominated flame retardant having a 2,3-dibromo-2-alkylpropyl structure and another flame retardant. Examples of the brominated flame retardant having the 2,3-dibromo-2-alkylpropyl structure include tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol S-bis ( 2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol F-bis (2,3-dibromo-2-methylpropyl ether) and the like, among which tetrabromobisphenol A-bis (2,3 -Dibromo-2-methylpropyl ether) is preferred.

  The content of the flame retardant in the polystyrene-based resin extruded foam heat insulating plate is 1-10 per 100 parts by weight of the base resin in order to improve the flame retardancy and to suppress a decrease in foamability and a decrease in mechanical properties. Parts by weight are preferred, 1.5-7 parts by weight are more preferred, and 2-5 parts by weight are even more preferred.

  Furthermore, in this invention, a flame retardant adjuvant can be used in combination with the said flame retardant for the purpose of further improving the flame retardance of an extrusion foaming heat insulating board. Examples of the flame retardant aid include 2,3-dimethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane, 3,4 -Diphenylalkanes such as diethyl-3,4-diphenylhexane, 2,4-diphenyl-4-methyl-1-pentene, 2,4-diphenyl-4-ethyl-1-pentene, diphenylalkenes, poly-1,4 -Polyalkylated aromatic compounds such as diisopropylbenzene, triphenyl phosphate, cresyl di 2,6-xylenyl phosphate, antimony trioxide, antimony pentoxide, ammonium sulfate, zinc stannate, cyanuric acid, isocyanuric acid, triallyl isocyania Nitrogen-containing cyclic compounds such as nurate, melamine cyanurate, melamine, melam, melem Silicone compounds, boron oxide, zinc borate, inorganic compounds such as zinc sulfide, red phosphorus-based, ammonium polyphosphate, phosphazene, phosphorus-based compounds such as hypophosphorous acid salts and the like. These compounds can be used alone or in admixture of two or more.

  The flame retardant aid is used in an amount of 0.05 to 1 part by weight, preferably 0.1 to 0.5 part by weight in the case of diphenylalkane or diphenylalkene with respect to 100 parts by weight of the base resin. In the case of other flame retardant aids, 0.5 to 5 parts by weight, preferably 1 to 4 parts by weight are used.

  Since the extruded foam insulation board obtained by the present invention is mainly used as a thermal insulation material for construction, the extruded polystyrene described in “Measurement method A” defined in JIS A9511 (2006) 5.13.1. A high level of flame retardancy that satisfies the flammability standards for foam heat insulating plates is required. Furthermore, it is desirable that the extruded foam heat insulating board obtained by the present invention satisfies the standard of thermal conductivity defined in JIS A9511 (2006) 4.2. Therefore, the addition of HFO as a physical foaming agent and a saturated hydrocarbon having 3 to 5 carbon atoms in the present invention is performed so that both flame retardancy and thermal conductivity are compatible.

(IV) Heat insulation improver In this invention, a heat insulation improver can be further added to base resin, and heat insulation can be improved. Examples of the heat insulation improver include metal oxides such as titanium oxide, metals such as aluminum, fine powders such as ceramics, carbon black and graphite, infrared shielding pigments, hydrotalcite and the like. These can use 1 type (s) or 2 or more types. The addition amount of the heat insulation improver is 0.5 to 5 parts by weight, preferably 1 to 4 parts by weight, based on 100 parts by weight of the base resin.

(V) Other additives In the present invention, various additives such as air conditioners, colorants such as pigments and dyes, heat stabilizers and fillers are appropriately added to the base resin as necessary. can do. Examples of the air conditioner include conventionally known chemical foams such as talc, kaolin, mica, silica, calcium carbonate, barium sulfate, titanium oxide, aluminum oxide, clay, bentonite, diatomaceous earth and the like, and azodicarbodiamide. An agent or the like can be used. Of these, talc is preferred because it does not impair flame retardancy and allows easy adjustment of the bubble diameter. In particular, talc having a particle size of 0.1 to 20 μm, more preferably 0.5 to 15 μm as defined in JIS Z8901 (2006) is preferable. The addition amount of the cell regulator varies depending on the type of the regulator, the target cell diameter, and the like, but is generally 0.01 to 8 parts by weight, more preferably 0.01 to 5 parts by weight based on 100 parts by weight of the base resin. Parts, particularly 0.05 to 3 parts by weight are preferred.

  Hereinafter, various properties of the polystyrene resin extruded foam heat insulating plate obtained by the present invention will be described in detail.

(I) Apparent density The apparent density of the polystyrene resin extruded foam insulation board obtained by the present invention is 20 to 50 kg / cm ³ . In particular, by the production method of the present invention, a foam heat insulating plate having a relatively low apparent density in the above range and a high expansion ratio can be obtained. If the apparent density is too small, it is quite difficult to produce an extruded foam insulation board itself, and depending on the application, the mechanical strength becomes insufficient. On the other hand, if the apparent density is too large, it is difficult to exert sufficient heat insulation unless the thickness of the extruded foam heat insulating plate is considerably increased, and it is not preferable from the viewpoint of lightness. From this viewpoint, the apparent density of the extruded foam plate is preferably 25 to 40 kg / m ³ .

(Ii) Thickness The polystyrene resin extruded foam insulation board has a thickness of 10 to 150 mm for the purpose of use. When the thickness is too thin, there is a risk that the heat insulating property required particularly when used as a heat insulating material will be insufficient. On the other hand, depending on the size of the extruder, foaming may be difficult if the thickness is too thick. In terms of handling and manufacturing, a thickness of 15 to 120 mm is more preferable.

(Iii) Average cell diameter The average cell diameter in the thickness direction of the polystyrene resin extruded foam heat insulating plate is preferably 0.5 mm or less. Extruded foam insulation board having even higher heat insulation properties because the average cell diameter in the thickness direction is within the above range, and the infrared transmission can be suppressed in combination with the configuration of the apparent density range. Can be obtained. The average cell diameter in the thickness direction is preferably 0.05 to 0.3 mm.

The measurement method of the average bubble diameter in this specification is as follows. That is, the average cell diameter (D _T : mm) in the thickness direction of the extruded foam heat insulating plate and the average cell diameter (D _W : mm) in the width direction of the extruded foam heat insulating plate are vertical cross sections (extruded foam heat insulation) of the extruded foam heat insulating plate. The average cell diameter (D _L : mm) in the extrusion direction of the extruded foam insulation board is parallel to the extrusion direction of the extrusion foam insulation board (vertical section perpendicular to the extrusion direction of the board). , A microscopic magnified photograph of a vertical cross section that bisects at the center in the width direction. Next, a straight line is drawn in the direction to be measured on the magnified photograph, the number of bubbles intersecting the straight line is counted, and the length of the straight line (naturally, this length is the length of the straight line on the magnified photograph). Rather than refer to the true length of a straight line taking into account the magnification of the photograph), the average bubble diameter in each direction is determined by dividing by the number of counted bubbles.

The measurement method of the average bubble diameter will be described in detail. The measurement of the average bubble diameter (D _T : mm) in the thickness direction is obtained by taking three magnified microphotographs at the center and both ends of the vertical cross section in the width direction. In the above, a straight line over the entire thickness of the extruded foam insulation board is drawn in the thickness direction, and the average diameter of the bubbles existing on each straight line (the length of the straight line / the straight line) is calculated from the length of each straight line and the number of bubbles intersecting the straight line. The number of bubbles intersecting the straight line) is determined, and the arithmetic average value of the three average diameters thus determined is defined as the average bubble diameter in the thickness direction (D _T : mm).

The average cell diameter in the width direction (D _W : mm) was obtained by taking three magnified micrographs at the center and both ends of the vertical cross section in the width direction. A straight line having a length of 3 mm multiplied by the enlargement factor is drawn in the width direction at the equally dividing position, and the average diameter of the bubbles existing on each straight line is calculated from the number of bubbles intersecting the straight line by the formula (3 mm / (Number of bubbles intersecting with the straight line −1)), and the arithmetic average value of the average diameters of the three obtained locations is defined as the average cell diameter in the width direction (D _W : mm).

The average cell diameter in the extrusion direction (D _L : mm) is the center of the vertical cross section in the extrusion direction obtained by cutting the extruded foam insulation board in the extrusion direction at a position that bisects the width direction of the extrusion foam insulation board. Microscopic magnified photographs of a total of three locations of the head and both ends are obtained, and on each photograph, a straight line having a length obtained by multiplying the expanded foam heat insulating plate into two parts in the thickness direction by multiplying the expansion ratio by 3 mm And the average diameter of the bubbles existing on each straight line is obtained from the equation (3 mm / (number of bubbles intersecting the straight line −1)) from the number of bubbles intersecting the straight line. The arithmetic average value of the average diameters at the three locations is defined as the average cell diameter in the extrusion direction (D _L : mm). The horizontal direction of the average cell diameter of the extruded thermoplastic resin foam _(D H: mm) is the arithmetic mean value of _{D W} and _{D L.}

(Iv) Bubble deformation rate Furthermore, in the said polystyrene-type resin extrusion foaming heat insulation board, it is preferable that a bubble deformation rate is 0.7-2.0. 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 The larger the value is, the longer the image is. If the bubble deformation rate is too small, the compression strength may decrease because the bubbles are flat, and the flat bubbles tend to return to a spherical shape, so the dimensional stability of the extruded foam may also decrease. . When the bubble deformation rate is too large, the number of bubbles in the thickness direction is reduced, so that the effect of improving heat insulation by the bubble shape is reduced. From such a viewpoint, the bubble deformation rate is preferably 0.8 to 1.5, and more preferably 0.8 to 1.2. When the bubble deformation rate is within the above range, a polystyrene-based resin-extruded foam insulation board having excellent mechanical strength and higher heat insulation is obtained.

(V) Closed cell ratio The closed cell ratio of the polystyrene resin extruded foam insulation board is 80% or more. If the closed cell rate is too low, the HFO used as the foaming agent tends to dissipate from the foam insulation board at an early stage, which may reduce long-term heat insulation. From the above viewpoint, the closed cell ratio is preferably 85% or more, more preferably 90% or more, and further preferably 93% or more. The closed cell ratio S (%) is measured using an air comparison type hydrometer (for example, Toshiba Beckman Co., Ltd., air comparison type hydrometer, model: 930 type) according to the procedure C of ASTM-D2856-70. Is done.

  In the present specification, the closed cell ratio of the extruded foam insulation board is obtained from the following formula (1). Cut samples from a total of three locations near the center of the extruded foam insulation board and both ends in the width direction, using each cut sample as a measurement sample, measuring the closed cell rate for each measured sample, and measuring the 3 closed cell rates The arithmetic average value of is adopted. The cut sample is cut from the extruded foam insulation board to a size of 25 mm in length x 25 mm in width x 20 mm in thickness, and has no extruded foam insulation board, and when the sample is thin and 20 mm in the thickness direction cannot be cut out For example, two samples (cut samples) cut into a size of 25 mm long × 25 mm wide × 10 mm thick are stacked and measured.

However,
Vx: True volume (cm ³ ) of the cut sample obtained by measurement with the above air comparison type hydrometer (volume of resin constituting the cut sample of the extruded foam insulation board and total volume of bubbles in the closed cell portion in the cut sample Equivalent to the sum of
VA: apparent volume (cm ³ ) of the cut sample calculated from the outer dimensions of the cut sample used for measurement
W: Total weight of cut sample used for measurement (g)
ρ: Density (g / cm ³ ) of resin constituting the extruded foam insulation board

(Vi) Thermal conductivity The thermal conductivity (A) after 100 days from the production of the polystyrene-based resin extruded foam insulation board is desirably 0.0290 W / (m · K) or less, and is 0.0280 W / (m -K) More preferably, it is the following. In the foam insulation board obtained by the production method of the present invention, a foam insulation board having a high closed cell ratio is obtained, and dissipation of the HFO from the foam insulation board is effectively prevented. Even after a long time, the thermal conductivity is kept low.
In the present invention, the thermal conductivity is determined by cutting out a test piece having an extruded foam insulation board having a length of 200 mm, a width of 200 mm, and a thickness of 10 mm from the extruded foam insulation board, and the test piece described in JIS A 1412-2 (1999). It is measured based on a flat plate heat flow meter method (two heat flow meters, high temperature side 38 ° C., low temperature side 8 ° C., average temperature 23 ° C.). When a test piece having a thickness of 10 mm cannot be cut out, a plurality of thin test pieces (as few as possible) are stacked to obtain a test piece having a thickness of 10 mm. For example, when a foam insulation board having a thickness of 28 mm is sliced to a thickness of 10 mm, the measured value after 100 days from the production of the sliced sample corresponds to the value after 780 days from the foam insulation board (thickness 28 mm). .
The thermal conductivity (B) after 200 days from the production of the polystyrene-based resin extruded foam insulation board is desirably 0.0290 W / (m · K) or less, preferably 0.0280 W / (m · K) or less. More preferably. In the foam insulation board obtained by the production method of the present invention, since the closed cell rate is particularly high, the thermal conductivity is kept low even after 200 days have passed since the production, and the long-term heat insulation is excellent. .

(Vii) Residual amount of HFO in the foam insulation board In the polystyrene resin extruded foam insulation board obtained by the present invention, the residual amount of HFO in the foam insulation board should be 0.02 mol or more per 1 kg of the extruded insulation foam board. Is preferred. If it is in the said range, HFO will exhibit the heat insulation improvement effect effectively and will become more excellent in heat insulation. From the above viewpoint, the residual amount of HFO is more preferably 0.1 mol or more. On the other hand, the upper limit of the residual amount of HFO is related to the apparent density of the foam heat insulating plate and the like, but is approximately 0.8 mol, preferably 0.7 mol. The residual amount of HFO varies from immediately after manufacture, but it is sufficient that the residual amount of HFO is within the above range when the foam heat insulating board is used.
The residual amount of HFO in the foam insulation board in this specification is a value measured by an internal standard method using a gas chromatograph. Specifically, an appropriate amount of sample is cut out from the extruded foam insulation board, this sample is placed in a sample bottle with a lid containing an appropriate amount of toluene and an internal standard substance, the lid is closed, and the mixture is stirred well and the foam insulation board is placed. A gas chromatographic analysis is performed using a solution obtained by dissolving HFO in toluene in a sample for measurement, and the residual amount of HFO in the foam insulation board is obtained.

(Viii) Melt tension The melt tension (MT) of the base resin in the present invention is a value measured according to ASTM D1238, and can be measured by, for example, Capillograph 1D manufactured by Toyo Seiki Seisakusho.
Melt tension (MT) can be measured according to ASTM D1238, and can be measured by Capillograph 1D manufactured by Toyo Seiki Seisakusho. Using a cylinder with a cylinder diameter of 9.55 mm and a length of 350 mm, and an orifice with a nozzle diameter of 2.095 mm and a length of 8.0 mm, the cylinder and the orifice were set at a temperature of 200 ° C., and the required amount of sample was placed in the cylinder. After leaving for 4 minutes, the piston speed is 10 mm / min and the molten resin is extruded from the orifice into a string shape. The string is put on a 45 mm diameter tension detection pulley, and the take-up speed is 0 m / min to 200 m in 4 minutes. While the take-up speed was increased at a constant speed so as to reach 1 / min, the string-like material was taken up by the take-up roller to obtain the maximum value of the tension immediately before the string-like material was broken. Here, the reason why the time until the take-up speed reaches 0 m / min to 200 m / min is set to 4 minutes is to suppress the thermal deterioration of the resin and increase the reproducibility of the obtained value. Using a different sample for the above operation, measuring a total of 10 times, removing three values in order from the largest value of the maximum value obtained in 10 times, and three values in order from the smallest value of the maximum value, The value obtained by arithmetically averaging the remaining four local maximum values is the melt tension (cN).

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

(1) The raw materials used for the base resin in Examples and Comparative Examples are shown below.
(I) Base resin Table 1 shows polystyrene resins constituting the base resin.

(Ii) Masterbatch Air bubble modifier masterbatch: A talc masterbatch containing 60% by weight of talc (manufactured by Matsumura Sangyo Co., Ltd., trade name: High Filler # 12) using polystyrene resin as a base resin was used.

  Flame retardant master batch: Tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) (SR130 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and tetrabromobisphenol-A-bis (2 , 3-dibromopropyl ether) (SR720, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) A flame retardant masterbatch containing 50% by weight of a mixed flame retardant is added to the base resin of the mixed flame retardant in an amount of 5% by weight. It added to base resin so that it might become a part.

(Iii) Mixed physical foaming agent As the mixed physical foaming agent, HFO: trans-1,3,3,3-tetrafluoropropene (trans HFO-1234ze), saturated hydrocarbon having 3 to 5 carbon atoms: isobutane, water and A mixture of carbon dioxide and / or carbon dioxide was used.

(2) The evaluation method is described below.
(I) Cross-sectional area The cross-sectional area of the polystyrene resin extruded foam heat insulating plate is the cross-sectional area of a vertical cross section (width direction vertical cross section) orthogonal to the extrusion direction of the extruded foam heat insulating plate.

(Ii) Appearance The foam moldability was evaluated according to the following evaluation criteria.
◯: A plate-like extruded foam heat insulating board having a good foamed state and having no appearance of waves or spot holes on the surface and having a good appearance can be stably obtained.
X: The foamed state is poor, and undulations, spot holes, etc. are generated on the surface, and a good plate-like extruded foam heat insulating board cannot be obtained.

(Iii) Flame retardance The extruded foam insulation board immediately after production was transferred to a room with an air temperature of 23 ° C. and a relative humidity of 50%, and left in that room for 4 weeks, and then measured according to 4.13.1 “Measurement method” of JIS A9511 (1995). Measured based on “A”. In addition, the measurement cut out five test pieces from one foamed board (N = 5), and evaluated it with the following evaluation criteria.
A: All specimens disappeared within 3 seconds, and the average burning time of 5 specimens is within 2 seconds.
○: All specimens disappear within 3 seconds, and the average burning time of 5 specimens exceeds 2 seconds and is within 3 seconds.
X: The average burning time of 5 test pieces exceeds 3 seconds.

(Iv) Closed cell ratio It is the value measured by the procedure C of ASTM-D2856-70 using the cut sample which does not have the shaping | molding skin cut | disconnected from the extrusion foam to the size of 25 mm x 25 mm x 20 mm.

  The methods for measuring the apparent density, thickness direction average bubble diameter, average bubble deformation rate, and thermal conductivity are as described above.

Examples 1-9, Comparative Examples 1-5
A first extruder with an inner diameter of 65 mm, a second extruder with an inner diameter of 90 mm, and a third extruder with an inner diameter of 150 mm are connected in series, and a blowing agent inlet is provided near the end of the first extruder, A production apparatus was used in which a flat die provided with a resin discharge port (die lip) having a 1 mm × 90 mm wide cross section in the width direction was connected to the outlet of the third extruder.

  Further, a shaping device (guider) composed of a plate made of a pair of upper and lower polytetrafluoroethylene resins installed parallel to the resin outlet of the flat die is attached. Resin, flame retardant (5 parts by weight of flame retardant masterbatch), and bubble regulator (2.5 parts by weight of bubble regulator masterbatch) were added to the first extrusion so as to have the respective compounding amounts shown in Tables 2 and 3. Table 2 shows the physical foaming agents having the blending compositions shown in Tables 2 and 3 from the foaming agent inlet provided near the tip of the first extruder. The foamable resin melt supplied to the melt at the rate shown in the figure and melt-kneaded is supplied to the subsequent second and third extruders, and the resin temperature is shown in the table (this foaming temperature). Is the temperature of the foamable resin melt measured at the position of the junction between the extruder and the die), then extruded from the die lip into the guider at a discharge rate of 50 kg / hr, and 28 mm in the thickness direction while foaming. Passing through guiders arranged in parallel with a gap of It was produced extruded polystyrene resin foam of the molded into a plate (shaping) the plate by causing. The evaluation results are summarized in Tables 2 and 3.

From Tables 2 and 3,
(1) As seen in Examples 1 to 5, the thermal conductivity tends to decrease as the blending ratio of HFO in the mixed foaming agent increases. However, as seen in Comparative Example 2, when the blending ratio of HFO in the mixed foaming agent exceeds the range specified in the present invention and becomes relatively large, the closed cell ratio is lowered, the thermal conductivity is deteriorated, and foaming is performed. The appearance of the molded product is deteriorated. On the other hand, as can be seen from Comparative Example 1, when the blending ratio of HFO in the mixed foaming agent does not satisfy the range specified in the present invention, the thermal conductivity is already 0.029 W / m · K after 100 days. Therefore, a foam heat insulating board having good long-term heat insulating properties cannot be obtained.
(2) When Examples 3 and 6 are compared, Example 6 is excellent in long-term heat insulation because the blending ratio of HFO in the mixed foaming agent is relatively large. Moreover, Example 7 is contrasted with Example 2, and since the amount of isobutane is large, the flame retardancy is slightly lowered. Examples 8 and 9 are contrasted with Example 3 and show examples in which the types of base resin are different.
(3) When the blending amount of water in the mixed foaming agent exceeds the specified range of the present invention, the appearance of the foam insulation board deteriorates as seen in Comparative Example 3, and a good foam insulation board cannot be obtained. When the blending amount of isobutane in the mixed foaming agent is not more than the specification of the present invention, as seen in Comparative Example 4, the stability of extrusion foaming is lowered and the appearance of the foamed molded product is deteriorated. On the other hand, if the blending amount of isobutane in the mixed foaming agent exceeds the provisions of the present invention, the flame retardancy decreases as seen in Comparative Example 5.

Claims (3)

A foamable resin melt containing a base resin mainly composed of polystyrene resin, a physical foaming agent, and a flame retardant is extruded and foamed, thickness is 10 to 150 mm, apparent density is 20 kg / m ³ or more and less than 40 kg / m ³ , A method for producing an extruded foam insulation board having a closed cell ratio of 80% or more, wherein the physical foaming agent is 3 to 50 mol% hydrofluoroolefin and 30 to 70 mol% carbon number 3 to 5 saturation. Hydrocarbon, 15 to 50 mol% water and / or carbon dioxide (however, the total amount of the hydrofluoroolefin, the saturated hydrocarbon having 3 to 5 carbon atoms, and the water and / or carbon dioxide) Is 100 mol%.), The saturated hydrocarbon having 3 to 5 carbon atoms is n-butane and / or isobutane, and the average foam deformation rate of the extruded foam insulation board is 0.7 to 2.0. Method for producing extruded polystyrene resin foam of which is characterized in that.   The total blending amount of the hydrofluoroolefin and the saturated hydrocarbon having 3 to 5 carbon atoms is 0.4 to 2 mol per kg of the base resin, and the total blending amount of the water and / or carbon dioxide is the above. It is 0.05-0.6 mol per kg of base resin, The manufacturing method of the polystyrene-type resin extrusion foam heat insulating board of Claim 1 characterized by the above-mentioned.   The said hydrofluoroolefin is tetrafluoropropene, The manufacturing method of the polystyrene-type resin extrusion foaming heat insulation board of Claim 1 or 2 characterized by the above-mentioned.