JP2017095618A - Manufacturing method of polystyrene resin foam sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a polystyrene resin foam sheet capable of stably manufacturing a foam sheet excellent in fire retardancy or adiabaticity and good in appearance by using a foaming agent excellent in environmental compatibility.SOLUTION: There is provided a manufacturing method of a polystyrene resin foam sheet having apparent density of 20 kg/mor more and less than 40 kg/m, including a process of extruding a foamable molten resin composition by mixing a polystyrene resin, a physical foaming agent and a fire retardant to plate-like mold the same, wherein a foaming agent consisting of (A) saturated hydrocarbon having 3 to 6 carbon atoms of 45 mol% to 60 mol%, (B) dimethylether of 5 mol% to 40 mol%, (C) trans-1-chloro-3,3,3-trifluoropropene of 5 mol% to 40 mol%, (D) other physical foaming agent of 35 mol% or less including 0, where total amount of (A), (B), (C) and (D) is 100 mol%, is used as the physical foaming agent and total blended amount of the physical foaming agent is 1.0 to 2.0 mol based on 1 kg of the polystyrene resin.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a polystyrene-based resin foam plate, and more specifically, a polystyrene-based resin foam plate that can be used as a foam heat-insulating plate that can be suitably used as a heat-insulating material such as a wall, floor, or roof of a building. The present invention relates to a method for producing a polystyrene resin foam plate that can be stably produced using a physical foaming agent having excellent environmental compatibility.

  Polystyrene resin foam plates (hereinafter also simply referred to as “foam plates”) are widely used as heat insulating materials and the like because they have excellent heat insulation and mechanical strength. Such a plate-like foam plate is generally obtained by extruding a foamable molten resin kneaded product obtained by heat-melting a polystyrene resin in an extruder and then injecting and kneading a physical foaming agent into the obtained melt. It is manufactured by extruding and foaming from a flat die attached to the front end of the machine to a low pressure region and forming it into a plate shape with a forming tool.

  Conventionally, chlorinated fluorinated hydrocarbons (CFC) such as dichlorodifluoromethane have been used as physical foaming agents used in the production of polystyrene-based resin foam plates. CFC facilitates foaming of the foamable molten resin kneaded product, and CFC remains in the produced foamed plate for a long period of time, thereby contributing to a reduction in the thermal conductivity of the foamed plate. However, since CFC affects the destruction of the ozone layer, it currently has an ozone destruction coefficient of 0 (zero) instead of CFC, and has a small global warming potential. Saturated hydrocarbons are widely used.

  However, saturated hydrocarbons such as butane remain in the foam plate and contribute to the reduction of thermal conductivity. However, since they have the property of being easily combusted, when used in large quantities, the foam plate In order to maintain the flame retardancy, it is necessary to increase the amount of flame retardant used, which may lead to an increase in cost during foamed plate production, and may reduce the extrusion foamability of the foamed molten resin kneaded product. is there. For this reason, the amount used is limited.

  On the other hand, as a method for producing a foam plate having a high foaming ratio, it has been proposed to use ether in combination with a saturated hydrocarbon, which is excellent in environmental compatibility and quickly dissipates from the foam plate. Specifically, Patent Documents 1 and 2 describe the use of a specific ratio of a saturated hydrocarbon having 3 to 5 carbon atoms and an ether such as dimethyl ether as a foaming agent.

  Here, dimethyl ether is a foaming agent that is particularly excellent in extrusion foaming properties among easily dissipating physical foaming agents, but has a property that it is extremely flammable. The possibility that the dimethyl ether dissipated from the plate was ignited by static electricity increased, leaving a problem in terms of safety. Moreover, although dimethyl ether is easily dissipative, a part of the dimethyl ether remains in the foamed plate, so that when used in a large amount, the flame retardancy of the foamed plate may be reduced.

  As a technique for reducing the amount of dimethyl ether used for such a problem, for example, Patent Document 3 describes that four types of blowing agents such as isobutane, dimethyl ether, alcohol, and carbon dioxide are used at a specific ratio as a blowing agent. Has been.

Japanese Patent Laid-Open No. 11-158317 International Publication No. 99/054390 JP 2006-188654 A

  However, in the case of the production method of Patent Document 3, there is room for improvement in terms of production stability when producing a foamed plate having a certain foaming ratio or more and particularly a thick foam.

  The present invention has been made in view of the circumstances as described above, and uses a foaming agent excellent in environmental compatibility, and stably produces a foam plate having excellent flame retardancy and heat insulating properties and good appearance. An object of the present invention is to provide a method for producing a polystyrene-based resin foam plate that can be used.

This invention provides the manufacturing method of the polystyrene-type resin foam board as described in the following.
1stly, the manufacturing method of the polystyrene-type resin foam board of this invention includes the process of extruding the foamable molten resin composition formed by knead | mixing a polystyrene-type resin, a physical foaming agent, and a flame retardant, and shape | molding in plate shape. A method for producing a polystyrene-based resin foam plate having an apparent density of 20 kg / m ³ or more and less than 40 kg / m ³ , as a physical foaming agent, a saturated hydrocarbon (A) having 3 to 6 carbon atoms of 45 to 60 mol%, 5 mol% or more and 40 mol% or less of dimethyl ether (B), 5 mol% or more and 40 mol% or less of trans-1-chloro-3,3,3-trifluoropropene (C), and 35 mol% or less (including 0) of other Using a foaming agent comprising a physical foaming agent (D) (provided that the total amount of (A), (B), (C), and (D) is 100 mol%), and a physical foaming agent Method for producing a polystyrene resin foam sheet, wherein the total amount is 1.0~2.0mol against polystyrene resin 1 kg.
2ndly, in the manufacturing method of the polystyrene-type resin foam board of said 1st invention, the said other physical foaming agent (D) is at least 1 sort (s) of physical foaming agents selected from water, ethanol, and a carbon dioxide. Preferably there is.
3rdly, in the manufacturing method of the polystyrene-type resin foam board of the said 1st or 2nd invention, as said other physical foaming agent (D), the foaming agent containing ethanol aqueous solution is used, and in this ethanol aqueous solution, The molar ratio of ethanol and water (ethanol: water) is preferably 0.1: 1 to 0.6: 1.
Fourth, in the method for producing a polystyrene resin foam board according to any one of the first to third inventions, the flame retardant preferably contains a brominated butadiene-styrene copolymer.

According to the method for producing a polystyrene-based resin foam plate of the present invention, foaming containing, as a foaming agent, a saturated hydrocarbon having 3 to 6 carbon atoms, dimethyl ether, and trans-1-chloro-3,3,3-trifluoropropene. By using these agents at a specific ratio, it is possible to obtain a foamed plate having excellent appearance and excellent flame retardancy and thermal conductivity over an apparent density range of 20 kg / m ³ or more and less than 40 kg / m ^3. It can be manufactured stably.

<Method for producing foam plate>
Hereinafter, the manufacturing method of the polystyrene-type resin foam board of this invention is demonstrated in detail.

The method for producing a polystyrene-based resin foam plate of the present invention includes a step of extruding a foamable molten resin composition obtained by kneading a polystyrene-based resin, a physical foaming agent and a flame retardant to form a plate, and has an apparent density of 20 kg / A polystyrene-based resin foam board with m ³ or more and less than 40 kg / m ³ is produced.

  Specifically, in the method for producing a polystyrene-based resin foam plate of the present invention, for example, a polystyrene-based resin, a flame retardant, and an additive such as a bubble adjusting agent blended as necessary are supplied to an extruder. Then, the mixture is heated and kneaded, and a physical foaming agent is injected and kneaded, and then cooled to a suitable foaming temperature to obtain a foamable molten resin composition. The foamable molten resin composition is extruded through a flat die into a low pressure region and foamed, and a polystyrene resin foamed plate can be obtained by molding (forming) into a plate shape with a molding tool. The plate-shaped shaping can be performed, for example, by passing a molding tool composed of a pair of upper and lower plate-like bodies arranged downstream of the die and a molding tool such as a molding roll.

<Polystyrene resin>
Examples of the polystyrene resin used in the method for producing a polystyrene resin foamed plate of the present invention include polystyrene, a styrene-methyl acrylate copolymer and a styrene-ethyl acrylate copolymer containing 50 mol% or more of a styrene unit component. Styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-maleic anhydride copolymer, styrene-polyphenylene ether copolymer 1 type or 2 types selected from a polymer, a styrene-acrylonitrile copolymer, a styrene-methylstyrene copolymer, a styrene-dimethylstyrene copolymer, a styrene-ethylstyrene copolymer, a styrene-diethylstyrene copolymer, etc. The above can be illustrated. Among these, polystyrene can be preferably used. In addition to the styrene unit component, polystyrene may contain a unit component by a branching agent such as a polyfunctional monomer or a polyfunctional macromonomer.

(Other polymers)
The polystyrene resin may contain other polymers as long as the object and effect of the present invention are achieved. Other polymers include polyethylene resins (one or a mixture of two or more selected from the group consisting of ethylene homopolymers and ethylene copolymers having an ethylene unit component content of 50 mol% or more), polypropylene-based resins Resins (one or a mixture of two or more selected from the group of propylene homopolymers and propylene copolymers having a propylene unit component content of 50 mol% or more), polyphenylene ether resins, polymethyl methacrylate, etc. Thermoplastic resin, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer hydrogenated product, styrene-isoprene-styrene block copolymer hydrogenated product And thermoplastic elastomers such as styrene-ethylene copolymer. These other polymers are mixed according to the purpose so as to be less than 50% by mass in the polystyrene resin, preferably 30% by mass or less, and more preferably 10% by mass or less. can do.

  Moreover, in order to improve the heat insulation of a foamed board, what contains an amorphous polyethylene terephthalate type-copolymer can be used as a polystyrene-type resin. In this case, the amorphous polyethylene terephthalate resin is preferably blended in the polystyrene resin so as to be 5% by mass or more and less than 50% by mass.

Further, from the viewpoint of foamability and moldability, it is preferable to use a polystyrene resin having a melt viscosity (under conditions of 200 ° C. and a shear rate of 100 sec ⁻¹ ) of about 500 to 2500 Pa · s, more preferably. 600 to 2000 Pa · s, more preferably 700 to 1500 Pa · s.

<Physical foaming agent>
In the present invention, the physical foaming agent includes three kinds of saturated hydrocarbons having 3 to 6 carbon atoms (A), dimethyl ether (B), and trans-1-chloro-3,3,3-trifluoropropene (C). Things are used. These three types of physical foaming agents have an ozone depletion coefficient of 0, a low global warming coefficient, and excellent environmental compatibility.

  The physical foaming agent does not need to be composed of only the three types of physical foaming agents (A), (B), and (C), and other physical foaming agents as long as the object of the present invention is not impaired. (D) may be included. In this case, the ratio of the three types of physical foaming agents (A), (B), and (C) is 65 mol% or more, more preferably 70 mol% or more, still more preferably 75 mol%, based on the entire physical foaming agent. As mentioned above, More preferably, it is 80 mol% or more. Moreover, it is preferable that the upper limit is about 5 mol% in general, More preferably, it is 10 mol%.

  Moreover, in order to obtain the foamed board of the apparent density prescribed | regulated by this invention, the total amount of a physical foaming agent is 1.0-2.0 mol of physical foaming agents with respect to 1 kg of polystyrene-type resin.

  In addition, the compounding quantity of each foaming agent in the physical foaming agent mentioned later is a C3-C6 saturated hydrocarbon (A), dimethyl ether (B), trans-1-chloro-3,3,3-trifluoropropene. It is a ratio with respect to 100 mol% of the total amount of (C) and other physical foaming agents (D).

(C3-C6 saturated hydrocarbon (A))
The saturated hydrocarbon (A) having 3 to 6 carbon atoms in the present invention is excellent in the extrusion foamability of the polystyrene resin because it has a good balance between the solubility in the polystyrene resin and the diffusibility in the polystyrene resin.

  Examples of the saturated hydrocarbon having 3 to 6 carbon atoms (A) include propane, normal butane, isobutane (2-methylpropane), normal pentane, isopentane (2-methylbutane), cyclobutane, neopentane (2,2-dimethylpropane). ), Cyclopentane, normal hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, cyclohexane and the like. Two or more of these may be used in combination.

  The compounding quantity of a C3-C6 saturated hydrocarbon (A) is 45 mol% or more and 60 mol% or less. When the blending amount of the saturated hydrocarbon having 3 to 6 carbon atoms (A) is within this range, high flame retardancy and high heat insulation that satisfy the flammability standard of JIS A9511: 2006R are stably secured. can do. From the viewpoint of flame retardancy of the foamed plate, the upper limit of the blending amount of the saturated hydrocarbon having 3 to 6 carbon atoms (A) is preferably 58 mol%, more preferably 56 mol%.

  From the above viewpoint, the blending amount of the saturated hydrocarbon having 3 to 6 carbon atoms (A) with respect to 1 kg of the polystyrene-based resin is preferably 0.4 to 0.8 mol, more preferably 0.5 to 0.00. 7 mol.

(Dimethyl ether (B))
In this invention, the compounding quantity of dimethyl ether (B) is 5 mol% or more and 40 mol% or less.

  If the blending amount of dimethyl ether (B) is too small, the polystyrene-based resin becomes difficult to be plasticized, so that the extrusion stability during the production of the foamed plate is lowered and the width of the foamed plate is likely to vary. Manufacturing stability may be reduced.

  Moreover, when there are too many compounding quantities of dimethyl ether, there exists a possibility that the dimethyl ether dissipated from the foam board at the time of foam board manufacture may ignite by static electricity, and may reduce the safety at the time of manufacture. Further, it may be difficult to satisfy the flammability standard defined in JIS A9511 (2006R) 5 · 13 · 1.

  From the above viewpoint, the upper limit of the amount of dimethyl ether (B) is preferably 35 mol%, more preferably 30 mol%.

  Moreover, it is preferable that the compounding quantity of dimethyl ether (B) is 0.1-0.5 mol with respect to 1 kg of polystyrene-type resin.

(Trans-1-chloro-3,3,3-trifluoropropene (C))
Trans-1-chloro-3,3,3-trifluoropropene (C) is a physical foaming agent excellent in environmental compatibility with an ozone depletion coefficient of 0 and a very low global warming potential. Moreover, it has the property which does not burn easily, and has an appropriate plasticizing effect for styrene-based resins, and has a low thermal conductivity in a gaseous state. Therefore, trans-1-chloro-3,3,3-trifluoropropene (C) can be suitably used for the production of a styrene resin extruded foam plate using a foaming agent.

  For these reasons, the styrene-based resin extruded foam plate obtained using a foaming agent containing trans-1-chloro-3,3,3-trifluoropropene (C) has excellent heat insulation performance and is also a flame retardant. The amount added can be reduced. Further, it is possible to reduce the risk of ignition due to static electricity during the production of the foam plate.

  In the present invention, the amount of trans-1-chloro-3,3,3-trifluoropropene (C) is 5 mol% or more and 40 mol% or less.

  If the blending amount of trans-1-chloro-3,3,3-trifluoropropene is too small, the extrusion stability during the production of the foamed plate is lowered, and the number of carbon atoms is 3 in order to maintain the desired thermal conductivity. Since the blending amount of the saturated hydrocarbons of -6 must be increased, it may be difficult to satisfy the flammability standard defined in JIS A9511 (2006R) 5 · 13 · 1. Moreover, when there is too much compounding quantity of trans-1-chloro-3,3,3-trifluoropropene, it is difficult to dissolve a foaming agent in resin, and there exists a possibility that it may lack manufacturing stability.

  From the above viewpoint, the upper limit of the amount of trans-1-chloro-3,3,3-trifluoropropene (C) is preferably 35 mol%, more preferably 30 mol%, still more preferably 25 mol%, particularly preferably 20 mol. %.

  Moreover, it is preferable that the compounding quantity of trans-1-chloro-3,3,3-trifluoropropene (C) with respect to 1 kg of polystyrene-type resin is 0.05-0.5 mol, More preferably, it is 0.05- The amount is 0.45 mol, more preferably 0.05 to 0.4 mol, and particularly preferably 0.05 to 0.3 mol.

<Mole ratio of physical foaming agent>
(Mol ratio of (A) and (C))
From the viewpoint of the balance between the thermal conductivity, flame retardancy, and extrusion foamability of the foam plate, (A) the saturated hydrocarbon (A) having 3 to 6 carbon atoms and trans-1-chloro-3,3,3- The molar ratio (A: C) of trifluoropropene (C) is preferably 1: 0.1 to 1: 0.8, more preferably 1: 0.1 to 1: 0.7, Preferably it is 1: 0.1 to 1: 0.6.

(Mol ratio of (B) and (C))
From the viewpoint of flame retardancy of the foam plate, extrusion foamability, and safety during production of the foam plate, the molar ratio of dimethyl ether (B) and trans-1-chloro-3,3,3-trifluoropropene (C) ( B: C) is preferably from 1: 0.1 to 1: 3, more preferably from 1: 0.2 to 1: 2, and even more preferably from 1: 0.2 to 1: 1.

(Other physical foaming agents (D))
The other physical foaming agent (D) is particularly suitable as long as it is a foaming agent that does not impair environmental compatibility, safety during foamed plate production, extrusion foamability of the foamable molten resin kneaded product, and flame retardancy of the foamed plate itself. Although not limited, for example, hydro (chloro) fluoroolefins other than trans-1-chloro-3,3,3-trifluoropropene, water, alcohol, carbon dioxide, methyl formate, and two or more of these Examples include physical foaming agents selected from the group consisting of combinations. Among these, it is preferable to use at least one physical foaming agent selected from water, alcohol, and carbon dioxide.

In this invention, the compounding quantity of another physical foaming agent (D) is 35 mol% or less (0 is included). By setting the blending amount of the other physical foaming agent (D) within the above range, a foamed plate having a good appearance can be more stably produced over a range of an apparent density of 20 kg / m ³ or more and less than 40 kg / m ^3. be able to.
When the other physical foaming agent (D) is blended, the blending amount can be appropriately adjusted according to the desired apparent density of the foamed plate, but the lower limit is preferably approximately 5 mol%, more Preferably it is 10 mol%.

(carbon dioxide)
In the present invention, carbon dioxide can be preferably used among the other physical foaming agents (D). When carbon dioxide is used, the blending amount is preferably approximately 0.05 to 0.5 mol, more preferably 0.1 to 0.3 mol, with respect to 1 kg of polystyrene resin.

(Ethanol aqueous solution)
Moreover, in this invention, ethanol aqueous solution can be preferably used as another physical foaming agent (D). Ethanol is easily available industrially and is a foaming agent with excellent extrusion foamability. Water is a foaming agent with excellent foaming efficiency.
In the case of using an ethanol aqueous solution, the blending amount thereof is 5 mol% or more and 30 mol% or less in the physical foaming agent, and the molar ratio of ethanol and water (ethanol: water) in the ethanol aqueous solution is 0.1: 1 to 1. Preferably it is 0.6: 1.

  By using ethanol and water as an aqueous ethanol solution, and further using the blending amount of the ethanol aqueous solution and the molar ratio of ethanol and water in the above range, the dispersibility of water in the polystyrene resin is further improved, and the polystyrene resin The extrusion foamability can be further improved. Further, when carbon dioxide is used in combination with ethanol water as the foaming agent, the solubility of carbon dioxide in the polystyrene resin can also be improved.

  Further, by using an ethanol aqueous solution, the production stability when obtaining a foamed plate having a large cross-sectional area, particularly at a high foaming ratio (low apparent density), is further improved, and a foamed plate having a good appearance is more easily obtained. .

  From the above viewpoint, the upper limit of the amount of the aqueous ethanol solution is more preferably 25 mol%, and further preferably 20 mol%. Moreover, it is more preferable that the molar ratio of ethanol and water in the ethanol aqueous solution is 0.3: 1 to 0.6: 1.

  Moreover, it is preferable that the compounding quantity of the ethanol aqueous solution with respect to 1 kg of polystyrene-type resin is about 0.1-0.5 mol in general, More preferably, it is 0.1-0.4 mol.

<Flame Retardant>
The flame retardant used in the present invention is not particularly limited, but a brominated flame retardant can be preferably used. Brominated flame retardants include brominated butadiene polymers such as brominated butadiene-styrene copolymers, 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), tetrabromobisphenol-A-bis (2,3- Brominated bisphenol compounds typified by dibromopropyl ether), tetrabromobisphenol-S-bis (2,3-dibromopropyl ether), tetrabromobisphenol-F-bis (2,3-dibromopropyl ether), tris (2 , 3-Dibromopropyl) isocyanurate, mono (2 3,4-tribromobutyl) isocyanurate, di (2,3,4-tribromobutyl) isocyanurate, brominated isocyanurate represented by tris (2,3,4-tribromobutyl) isocyanurate, etc. Can be mentioned. One or more of these brominated flame retardants can be mixed and used.

  In addition to these brominated flame retardants, cresyl di 2,6-xylenyl phosphate, antimony trioxide, antimony pentoxide, ammonium sulfate, zinc stannate, cyanuric acid, pentabromotoluene, isocyanuric acid, triallyl isocyanurate , Nitrogen-containing cyclic compounds such as melamine cyanurate, melamine, melam, melem, silicone compounds, inorganic compounds such as boron oxide, zinc borate, zinc sulfide, phosphate esters represented by triphenyl phosphate, red phosphorus Phosphorus compounds such as ammonium polyphosphate, phosphazene, hypophosphite and the like can be used in combination.

  Among these flame retardants, since high flame retardancy can be imparted to the foamed plate, brominated butadiene-styrene copolymer, tetrabromobisphenol A-bis (2,3-dibromopropyl ether) (2,2-bis [ 4- (2,3-dibromopropoxy) -3,5-dibromophenyl] propane), tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) (2,2-bis [4- ( 2,3-dibromo-2-methylpropoxy) -3,5-dibromophenyl] propane), a flame retardant containing one or more of tris (2,3-dibromopropyl) isocyanurate is preferably used. . Also, among these, high flame retardancy can be imparted, polystyrene resin is not easily decomposed during extrusion, and it is stable even in the case of a high expansion ratio (low apparent density) and a larger cross-sectional area. Therefore, it is more preferable to use a flame retardant containing a brominated butadiene-styrene copolymer.

  The blending amount of the flame retardant is generally about 0.1 with respect to 100 parts by mass of the polystyrene resin from the viewpoint of imparting high flame retardancy to the foamed plate and suppressing the extrusion foamability and mechanical properties. It is 10 mass parts, More preferably, it is 0.5-7 mass parts, More preferably, it is 1-6 mass parts.

<Additives>
(Flame retardant aid)
In the method for producing a polystyrene resin foam board of the present invention, a flame retardant aid is used in combination with the above flame retardant as an additive for the purpose of further improving the flame retardancy of the foam board. Can do. 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 -1 type, or 2 or more types selected from polyalkylated aromatic compounds, such as diisopropylbenzene, can be illustrated. The compounding amount of the flame retardant aid is generally 0.01 to 1 part by mass, more preferably 0.05 to 0.5 part by mass, with respect to 100 parts by mass of the polystyrene resin.

(Insulation improver)
In the manufacturing method of the polystyrene-type resin foam board of this invention, the heat insulation can also be improved further by making a polystyrene-type resin foam board contain a heat insulation improver.

Examples of the heat insulation improver include fine powders having a radiation suppressing effect. Specifically, metal oxides such as titanium oxide, metals such as aluminum, ceramics, carbon black, graphite, infrared shielding One type or two or more types selected from pigments, hydrotalcite and the like can be exemplified.
The addition amount of the heat insulation improver is generally 0.5 to 5 parts by mass, more preferably 1 to 4 parts by mass with respect to 100 parts by mass of the polystyrene resin.

(Other additives)
Moreover, in the manufacturing method of the polystyrene-type resin foam board of this invention, another well-known additive can be suitably mix | blended with a polystyrene-type resin as needed. Examples of the other additives include various additives such as a bubble diameter expanding agent, a bubble adjusting agent, a colorant such as a pigment and a dye, a heat stabilizer, and a filler.

  The stabilizer can improve the thermal stability of the brominated flame retardant at the time of extrusion, for example, when producing a foamed plate or recycling the end material of the foamed plate and re-pelletizing. Examples of the heat stabilizer include bisphenol type epoxy compounds such as EPICLON series manufactured by DIC, novolac type epoxy compounds, (pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate). ] Or more heat stable selected from phosphite compounds such as hindered phenol compounds such as (bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite) Agents. In addition, it is preferable that the compounding quantity of this heat stabilizer is 0.1-40 mass parts with respect to 100 mass parts of total amounts of a flame retardant.

  As mentioned above, in the manufacturing method of the polystyrene-type resin foam board of this invention, as a physical foaming agent mix | blended with a foamable molten resin composition, it is a C3-C6 saturated hydrocarbon (45 mol% or more and 60 mol% or less) ( A) 5 mol% or more and 40 mol% or less of dimethyl ether (B), 5 mol% or more and 40 mol% or less of trans-1-chloro-3,3,3-trifluoropropene (C), and 35 mol% or less (including 0) Other physical foaming agents (D) (however, the total amount of (A), (B), (C), and (D) is 100 mol%), and the total amount of physical foaming agents is A physical foaming agent of 1.0 to 2.0 mol is used with respect to 1 kg of polystyrene resin.

  Thereby, the foamed board obtained by the manufacturing method of the polystyrene-type resin foamed board of this invention is prescribed | regulated to JIS A9511 (2006R) 5 * 13.1, when used as a heat insulating board for construction, "Measurement It has high flame retardancy satisfying the flammability standard for the extruded polystyrene foam heat insulating plate described in “Method A”, and satisfies the standard of thermal conductivity defined in JIS A9511 (2006R) 4.2. be able to. And furthermore, while being excellent in environmental compatibility, the foamed board which is excellent in a flame retardance can be manufactured safely.

(About physical properties of foamed plates)
Hereinafter, the physical property of the polystyrene resin foam board obtained by the manufacturing method of the polystyrene resin foam board of this invention is explained in full detail.

(Apparent density and size)
The apparent density of the foamed plate obtained by the production method of the present invention is 20 kg / m ³ or more and less than 40 kg / cm ³ . The foamed plate is plate-shaped, and its size can be appropriately set depending on the application, but usually the width is 800 mm or more and the thickness is about 10 to 150 mm. Further, it may be required to have a size larger than 80 mm and a cross-sectional area of the vertical cross section in the extrusion direction larger than 800 cm ² . Such a foam plate is usually manufactured by preparing a master plate that is one or more times larger than the desired size, cutting the master plate, and adjusting the width and length, and in some cases the thickness. The

  Here, if the width of the original plate greatly fluctuates during manufacture and the width becomes narrower than specified, a foamed plate having a specified size cannot be obtained, resulting in poor yield. In the production of a foamed plate, as described above, foaming tends to become more difficult as the foaming ratio is higher and the cross-sectional area is larger. According to the method for producing a polystyrene resin foam plate of the present invention, a foam plate having a good appearance can be stably produced even when producing a foam plate having a large thickness and a large cross-sectional area. Can do.

(Closed cell rate)
Further, the closed cell ratio of the foamed plate obtained by the production method of the present invention is preferably 85% or more, more preferably 90% or more, and further preferably 93% or more. When the closed cell ratio is in the above range, a physical foaming agent such as a saturated hydrocarbon having 3 to 6 carbon atoms or trans-1-chloro-3,3,3-trifluoropropene tends to stay in the bubble, and the foam plate High thermal insulation performance can be maintained over a long period of time. Moreover, it can be set as the foam board excellent also in mechanical strength.

  In addition, the closed cell ratio of a foam board uses the air comparison type hydrometer (for example, Toshiba Beckman Co., Ltd. make, air comparison type hydrometer, model: 930 type) according to the procedure C of ASTM-D2856-70. It can obtain | require from following formula (1) using the true volume Vx of the foam board measured.

  Specifically, cut samples were cut out from a total of three locations near the center of the foam plate and both ends in the width direction, and each cut sample was used as a measurement sample, and the closed cell ratio was measured for each measurement sample. The arithmetic average value of closed cell ratio is adopted. Note that the cut sample is a sample that does not have a foam plate skin cut to a size of 25 mm in length × 25 mm in width × 20 mm in thickness from the foam plate, 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.

  S (%) = (Vx−W / ρ) × 100 / (VA−W / ρ) (1)

However, Vx, VA, W, and ρ in the formula are as follows.
Vx: the true volume (cm ³ ) of the cut sample obtained by measurement with the above air comparison hydrometer (the volume of the resin constituting the cut sample of the foam plate and the total volume of bubbles in the closed cell portion in the cut sample Equivalent to sum.)
VA: apparent volume (cm ³ ) of the cut sample calculated from the outer dimensions of the cut sample used for measurement
W: Total mass of cut sample used for measurement (g)
ρ: Density of base resin constituting the foamed plate (g / cm ³ )

  EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples.

<Apparatus and materials>
In order to obtain the plate-like foamed plates of Examples and Comparative Examples, the following apparatuses and materials were used.

(Extruder)
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, a physical foaming agent injection port is provided near the end of the first extruder, and a resin discharge having a rectangular cross section with a gap of 4 mm and a width of 400 mm is provided. The extrusion apparatus which connected the flat die | dye provided with the exit (die lip) to the exit of the 2nd extruder was used. In addition, a molding apparatus (guider) in which a pair of upper and lower polytetrafluoroethylene resins was horizontally installed at a substantially constant interval was attached to the resin outlet of the second extruder.

(Polystyrene resin)
Polystyrene: (GPPS, Mw = 27 × 10 ⁴ )

(Flame retardants)
Brominated butadiene-styrene block copolymer: ICL JAPAN, product name “FR122P” (Br-SBS)

(Physical foaming agent)
(A) Isobutane: Mitsui Chemicals, Inc. (B) Dimethyl ether: Mitsubishi Gas Chemicals, Inc. (C) Trans-1-chloro-3,3,3-trifluoropropene: Honeywell Japan, Inc. (HCFO 1233zd)
(D1) Carbon dioxide: Showa Carbon Dioxide (D2) Ethanol: Yamaichi Chemical Industries ethanol aqueous solution: Yamaichi Chemical Industries (mol ratio ethanol: water = 37:63)

(Additive)
Bubble regulator: Talc (Matsumura Sangyo Co., Ltd., product name “High Filler # 12”)
Flame retardant aid: Poly-1,4-diisopropylbenzene (product name “CCPIB”, manufactured by United initiators)
Heat stabilizer: The following (1) to (3) were mixed at a ratio of (1) 50% by mass, (2) 25% by mass, and (3) 25% by mass.
(1) Novolac-type epoxy stabilizer: DIC, trade name “EPICLON N680”
(2) Phosphorous stabilizer: manufactured by ADEKA, trade name “PEP36” (bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite)
(3) Hindered phenol stabilizer: manufactured by BASF, trade name “Irganox 1010” (pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate])

<Examples and Comparative Examples>
(Examples 1-6)
Polystyrene resin, flame retardant, flame retardant aid, heat stabilizer, and talc as a bubble regulator are supplied to the first extruder in the formulation shown in Table 1, heated to 200 ° C., kneaded, and first extruded. From the physical foaming agent injection port provided in the machine, the physical foaming agent having the composition and amount shown in Table 1 was supplied. At this time, in Examples 1 to 5, water and ethanol were supplied as an aqueous ethanol solution. Next, the foaming agent-containing molten resin composition further kneaded in the first extruder is transferred to the subsequent second extruder, and the resin temperature is adjusted to the appropriate foaming temperature (extruded resin temperature) shown in Table 1. After forming into a foamable melted resin composition, it is extruded into a guider at a discharge rate of 800 kg / hr, and is formed into a plate shape (shaped) by passing through the guider while foaming to produce an original plate of the foamed plate, Furthermore, the width | variety and length of the original plate were adjusted by cutting, and the rectangular parallelepiped polystyrene-type resin foam board (width: 1000 mm, length: 2000 mm, thickness: 100 mm) was manufactured. In Table 1, when the corresponding foaming agent was not used, “−” was written.

(Comparative Example 1)
As Example 1-6 except that isobutane (50.0 mol%), dimethyl ether (21.8 mol%), carbon dioxide (15.5 mol%), and ethanol (12.7 mol%) were used as the physical foaming agent. The foamed board was manufactured by the manufacturing method.

(Comparative Example 2)
Examples were used except that isobutane (46.8 mol%), dimethyl ether (12.6 mol%), and trans-1-chloro-3,3,3-trifluoropropene (40.5 mol%) were used as physical blowing agents. The foam board was manufactured with the manufacturing method similar to 1-6.

(Comparative Example 3)
Comparative example except that isobutane (49.1 mol%), dimethyl ether (22.2 mol%), and trans-1-chloro-3,3,3-trifluoropropene (1.9 mol%) were used as physical foaming agents A foamed plate was produced by the same production method as in No. 1.

<Measurement method and evaluation method of foamed plate>
About the foamed plates of Examples 1 to 6 and Comparative Examples 1 to 3, the apparent density, thickness, cross-sectional area, closed cell diameter, thermal conductivity, flame retardancy, appearance, and production stability were measured and evaluated by the following methods. Went. In Table 1, the manufacturing conditions in Examples 1-6 and Comparative Examples 1-3, each measurement result, and an evaluation result are shown.

(Apparent density)
The apparent density of the foamed plate was determined as follows. The obtained foamed plate is cut out of a 50 × 50 × 50 mm rectangular parallelepiped sample from both the central portion and the vicinity of both ends thereof, and the mass is measured. The apparent density of each sample is obtained by dividing the mass by the volume. And the arithmetic average value thereof was regarded as the apparent density.

(Thickness)
The foamed plate was divided into five equal parts in the width direction, and the thicknesses of the central portions in the width direction were measured.

(Cross sectional area)
As the product of the thickness of the foam plate and the width of the foam plate, the cross-sectional area of the vertical cross section in the extrusion direction was determined. In addition, the width | variety of the foam board was calculated | required as an arithmetic average value of the width | variety of 5 places selected at random from the foam board.

(Independent bubble diameter)
The true volume Vx of the foam plate measured using an air-comparing hydrometer (for example, Toshiba Beckman Co., Ltd., air-comparing hydrometer, model: model 930) according to ASTM-D2856-70, Procedure C Was obtained from the above equation (1).

(Thermal conductivity)
The obtained foamed plate is stored in a constant temperature and humidity chamber at a temperature of 23 ° C. and a relative humidity of 50% immediately after manufacture, and after 7 days and 28 days of manufacture, the thermal conductivity defined by JIS A9511 (2006R) 4.2. Measured according to the standard.

(Flame retardance)
The obtained foamed plate is stored in a constant temperature and humidity chamber at a temperature of 23 ° C. and a relative humidity of 50% immediately after manufacture, and after 5 days of manufacture, it conforms to the flammability standard defined in JIS A9511 (2006R) 5.13.1. Measured along.

(appearance)
The smoothness of the foamed plate surface was evaluated visually.
○: smooth surface with no unevenness ×: surface is not smooth due to separation of foaming agent in the die

(Manufacturing stability)
The production stability at the time of extrusion was evaluated according to the following criteria based on the variation in the width of the obtained original plate (maximum value−minimum value).
○: The fluctuation of the width of the original plate is 30 mm or less.
X: The fluctuation | variation of the width | variety of an original plate may exceed 30 mm, and may fall below a regulation width (1000 mm).

  As shown in Table 1, 45 to 60 mol% C 3-6 saturated hydrocarbon (A), 5 to 40 mol% dimethyl ether (B), 5 to 40 mol% trans-1 -Chloro-3,3,3-trifluoropropene (C), and other physical foaming agents (D) of 35 mol% or less (including 0) (provided that (A), (B), (C), and Examples 1 to 6 in which the total amount of (D) is 100 mol% and the total amount of physical foaming agent is 1.0 to 2.0 mol per 1 kg of polystyrene resin. Then, it was confirmed that a foam board can be manufactured stably with a low apparent density. The obtained foamed board was confirmed to have excellent flame retardancy, excellent surface smoothness, and good appearance.

  On the other hand, in Comparative Examples 1 to 3, it was confirmed that it was difficult to stably produce a foam plate having a low apparent density. Moreover, as for the foamed board of Comparative Examples 1-3, the unevenness | corrugation was confirmed on the surface and the external appearance was not preferable.

From these results, according to the method for producing a polystyrene-based resin foam plate of the present invention,
It was confirmed that a foamed plate having excellent flame retardancy and good appearance can be stably produced, and a foamed plate having excellent thermal conductivity can be produced.

Claims (4)

Polystyrene resin, physical blowing agent and the foaming molten resin composition flame retardant obtained by kneading extruding includes the step of forming into a plate shape, apparent density 20 kg / m ³ or more 40 kg / m ³ of less than polystyrene type resin foamed A method of manufacturing a board,
As a physical foaming agent, 45 to 60 mol% of C3-C6 saturated hydrocarbon (A), 5 to 40 mol% of dimethyl ether (B), 5 to 40 mol% of trans-1-chloro- 3,3,3-trifluoropropene (C), and other physical foaming agents (D) of 35 mol% or less (including 0) (however, (A), (B), (C), and (D) And a total amount of physical foaming agent is 1.0 to 2.0 mol with respect to 1 kg of polystyrene resin. A manufacturing method of a foam board.   The method for producing a polystyrene-based resin foam board according to claim 1, wherein the other physical foaming agent (D) is at least one physical foaming agent selected from water, ethanol, and carbon dioxide. .   As the other physical foaming agent (D), a foaming agent containing an aqueous ethanol solution is used, and the molar ratio of ethanol to water (ethanol: water) in the aqueous ethanol solution is 0.1: 1 to 0.6: The method for producing a polystyrene-based resin foamed plate according to claim 1 or 2, wherein the number is 1. The said flame retardant contains a brominated butadiene-styrene-type copolymer, The manufacturing method of the polystyrene-type resin foam board as described in any one of Claim 1 to 3 characterized by the above-mentioned.