JP2011093951A - Foamable polystyrene-based resin particle for manufacturing under-roof heat insulation material, manufacturing method therefor, pre-foamed particle for under-roof heat insulation material, and under-roof heat insulation material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an under-roof heat insulation material excellent in environmental compatibility and flame-retardancy, a foamable polystyrene-based resin particle for manufacturing the under-roof heat insulation material used for the manufacturing, and a manufacturing method therefor. <P>SOLUTION: The foamable polystyrene-based resin particle for manufacturing the under-roof heat insulation material includes a flame-retardant having a bromine atom in the molecule, a bromine content of less than 70 mass% and having a benzene ring in the molecule and a 5 mass% decomposition temperature within a range of 200-300°C. The foamable polystyrene-based resin particles are obtained by a melt-extrusion method in which the flame-retardant and a foaming agent are added and kneaded to a polystyrene-based resin in a resin feeding apparatus, a melted resin containing the flame-retardant and the foaming agent is directly extruded from a small hole of a die provided on a distal end of the resin feeding apparatus into a cooling liquid, the extruded article is cut simultaneously when it is extruded, and the extruded article is cooled/solidified by contact with the liquid to obtain the foamable polystyrene-based resin particles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to an underfloor heat insulating material excellent in environmental compatibility and flame retardancy, an expandable polystyrene resin particle for producing an under roof heat insulating material used in the manufacture thereof, and a method for producing the same. The underfloor heat insulating material of the present invention is used, for example, as a heat insulating material laid between a base material such as a field board and a roofing material.

Conventionally, as roofing insulation, in addition to waterproofing, moisture absorption, moisture proofing, and heat insulation, it does not cause thermal degradation under repeated high temperatures due to direct sunlight (heat resistance), nails and There is a demand for not leaking water from the hole where the staples are struck and not expanding or contracting due to temperature change (dimensional stability).
Insulation used for the roof insulation is a work on the roof plate in addition to the required strength because the worker can walk on it during the construction process, From the viewpoints of work safety and simplicity, it is desired to be as light as possible, and a polystyrene resin foam molded body having a thickness of about 10 to 200 mm is often used as a heat insulating material.
Furthermore, the under-floor heat insulating material is usually required to have a certain level of flame retardant performance from the viewpoint of preventing the occurrence of fire and the like, and preventing the spread of fire due to the spread of fire in the event of a fire. In order to impart sufficient flame retardancy to a polystyrene resin foam molded article, a flame retardant is added to the expandable polystyrene resin particles for producing the foam molded article.
Further, under-the-floor heat insulating materials reduce the amount of volatile organic compounds (hereinafter sometimes abbreviated as VOC) such as formaldehyde, toluene, xylene, and styrene as countermeasures against sick house syndrome, which has been increasing in recent years. It is demanded.

Conventionally, for example, Patent Documents 1 to 3 have been proposed as techniques for imparting flame retardancy to polystyrene-based foamed molded articles.
Patent Document 1 discloses (A) an organic solvent liquid containing 0.1 to 10 parts by mass of a brominated flame retardant (I), or (B) a brominated flame retardant (100 parts by mass of styrene resin). An organic solvent liquid containing 0.1 to 10 parts by mass of I) and (II), and (C) a foaming agent is added and heated and foamed to produce a flame-retardant foamed styrene resin. A method is disclosed.
In Patent Document 2, tetrabromobisphenol A diallyl ether is dispersed so as to have a particle size of 50 μm or less in the presence of a surfactant, and then a polystyrene resin particle together with a softening agent, a flame retardant aid, a plasticizer, and a foaming agent. A method for producing self-extinguishing foamed polystyrene resin particles, characterized by impregnating in a resin, is disclosed.
Patent document 3 contains an organic bromine compound having a bromine content of 70% by weight or more as a flame retardant and is treated to provide a self-extinguishing foam that passes combustion test B2 (according to DIN 4102). Particulate expandable styrene polymers are disclosed which are characterized in that they can be made.

JP-A 63-172744 JP-A-11-130898 Special table 2001-525001 gazette

However, the above-described conventional technique has the following problems.
In Patent Document 1, a flame retardant is preliminarily dissolved in an organic solvent to be supplied into an extruder and an autoclave. However, the use of a volatile solvent in the step of dissolving in an organic solvent has a large adverse effect on the environment, and VOC It is not preferable from the viewpoint of generation. In addition, the process of dissolving in lower aliphatic hydrocarbons (butane and pentane) used for foaming is also dangerous because it may cause a fire due to volatilization of the foaming agent.

  In the prior art disclosed in Patent Document 2, a flame retardant is dispersed in the presence of a surfactant so that the particle diameter is 50 μm or less, and then a polystyrene resin together with a softener, a flame retardant aid, a plasticizer, and a foaming agent. Although the flame retardant-containing expandable polystyrene resin particles are produced by impregnating the particles, the method of impregnating the polystyrene resin particles with the flame retardant in this way impregnates the flame retardant near the surface of the polystyrene resin particles, There is no flame retardant near the center of the resin particles, or only low-content flame retardant-containing expandable polystyrene resin particles can be obtained. Such resin particles are pre-expanded, and the obtained pre-expanded particles are put into the mold. There is a problem that the flame-retardant polystyrene-based resin foam molded article obtained by foam molding is inferior in mechanical strength and has poor moldability and appearance.

  Furthermore, in Patent Document 3, a brominated flame retardant such as hexabromocyclododecane (HBCD) is used. Hexabromocyclododecane is a first-class monitoring chemical substance in the Chemical Substances Examination Regulation Law, and the existing chemistry of METI. Since there is a problem in safety such as difficulty decomposition and high concentration pointed out in the material safety inspection and it falls under the scope of European risk assessment assessment, it is desired to eliminate its use.

  The present invention has been made in view of the above circumstances, and provides a roof insulation material having sufficient flame retardancy using a flame retardant that is highly safe for the environment and living organisms, and excellent in mechanical strength and dimensional stability. Objective.

In order to achieve the above-mentioned object, the present invention is an expandable polystyrene resin particle for producing an under-floor heat insulating material having a polystyrene resin containing a flame retardant and a foaming agent as particles,
The flame retardant has a bromine atom in the molecule, a bromine content of less than 70% by mass, a benzene ring in the molecule, and a 5% by mass decomposition temperature of the flame retardant of 200 to 300 ° C. Within the range of
A flame retardant and foaming agent are added to and kneaded with polystyrene resin in the resin supply device, and the molten resin containing the flame retardant / foaming agent is extruded directly into the cooling liquid through a small hole in the die attached to the tip of the resin supply device. For extruding under the roof, characterized by cutting the extrudate at the same time as extruding, and cooling and solidifying the extrudate by contact with a liquid to obtain the foamed polystyrene resin particle melt extrusion method Expandable polystyrene resin particles are provided.

  In the expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, the total content of aromatic organic compounds consisting of styrene monomer, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene, toluene, benzene is less than 500 ppm. Is preferred.

  In the expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, the flame retardant is preferably one or more selected from the group consisting of tetrabromobisphenol A or a derivative thereof.

  In the expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, the flame retardant is tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis (2 , 3-dibromopropyl ether), tetrabromobisphenol A-bis (allyl ether), and preferably one or more selected from the group consisting of tetrabromobisphenol A-bis (allyl ether).

  Moreover, this invention provides the pre-expanded particle for roof under heat insulation manufacture obtained by heating the said foamable polystyrene-type resin particle for roof under heat insulation manufacture.

Moreover, the present invention provides a roof having a density in the range of 0.010 to 0.050 g / cm ³ obtained by filling the pre-expanded particles for manufacturing the under-floor heat insulating material into a cavity of a mold and heating and foaming. Provide lower insulation.

  Further, the present invention is obtained by filling the pre-expanded particles for producing the under-floor heat insulating material in a cavity of a molding die and heating and foaming. The foamed molded product having a foam expansion factor of 50 times has an average chord length of the bubbles of 50. Provide an under roof insulation that is in the range of ~ 350 μm.

  Further, the present invention provides a polystyrene resin in a resin supply apparatus having a bromine atom in the molecule, a bromine content of less than 70% by mass, a benzene ring in the molecule, and the flame retardant. A flame retardant and a foaming agent having a 5 mass% decomposition temperature in the range of 200 to 300 ° C. are added and kneaded, and the flame retardant / foaming agent-containing molten resin is directly from the small hole of the die attached to the tip of the resin supply device. In the method of extruding into a cooling liquid, cutting the extrudate at the same time as extruding, and cooling and solidifying the extrudate by contact with the liquid to produce expandable polystyrene resin particles, styrene monomer, ethylbenzene, isopropylbenzene, A roof characterized by obtaining expandable polystyrene resin particles without using an aromatic organic compound comprising normal propylbenzene, xylene, toluene and benzene To provide a method of manufacturing a heat insulating material for producing expandable polystyrene resin particles.

  In the method for producing expandable polystyrene resin particles for producing an under-floor heat insulating material according to the present invention, the flame retardant is preferably one or more selected from the group consisting of tetrabromobisphenol A or a derivative thereof. .

  In the method for producing expandable polystyrene resin particles for producing an under-floor heat insulating material according to the present invention, the flame retardant is tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-. One or more selected from the group consisting of bis (2,3-dibromopropyl ether) and tetrabromobisphenol A-bis (allyl ether) are preferred.

  In the method for producing expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, a master batch material containing the flame retardant at a predetermined concentration in a resin is supplied into a resin supply device together with the polystyrene resin, and the device It is preferable to melt-knead in the inside.

The expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention have a bromine atom in the molecule, a bromine content of less than 70% by mass, a benzene ring in the molecule, and the difficulty. It contains a flame retardant having a 5 mass% decomposition temperature in the range of 200 to 300 ° C. The flame retardant is highly safe for the environment and organisms. In particular, the tetrabromobisphenol A derivative can impart sufficient flame retardant performance when added to a polystyrene resin foamed molded article, and is safe for the environment and organisms. Since the safety is high, it is possible to provide a roof under heat insulating material excellent in safety.
The expandable polystyrene resin particles for producing an under-floor heat insulating material according to the present invention are prepared by adding a flame retardant and a foaming agent to a polystyrene resin in a resin supply device, kneading, and adding a flame retardant / foaming agent-containing molten resin to the resin supply device. Extrusion directly into the cooling liquid from the small hole of the die attached to the tip, and simultaneously extruding, cutting the extrudate, and cooling and solidifying the extrudate by contact with the liquid to obtain expandable polystyrene resin particles Since the flame retardant is uniformly present in the resin particles, the mechanical strength of the obtained under-floor insulation is higher than that obtained when the flame retardant is unevenly present in the resin particles. The roof under heat insulating material which becomes high and has excellent dimensional stability and formability can be obtained.

  The under-floor heat insulating material of the present invention heats and expands the expandable polystyrene resin particles for manufacturing the under-floor heat insulating material, and further heats the obtained pre-expanded particles in a mold cavity. Since it is obtained by foaming, it is possible to provide a roof insulation material that has sufficient flame retardancy using a flame retardant that is highly safe for the environment and living organisms, and that has excellent mechanical strength and dimensional stability. it can.

According to the method for producing expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, it is possible to efficiently produce expandable polystyrene resin particles for producing an under-floor heat insulating material having an excellent effect as described above. it can. In particular, according to the production method of the present invention, an expandable polystyrene system for producing an under-floor heat insulating material having a low content of an aromatic organic compound composed of a styrene monomer, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene, toluene, and benzene. Resin particles can be produced with high efficiency.
Further, in the method for producing expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, a master batch material containing the flame retardant at a predetermined concentration in the resin is supplied into the resin supply apparatus together with the polystyrene resin. By melt-kneading in the apparatus, the flame retardant can be more uniformly contained in the resin particles.

It is a block diagram which shows an example of the manufacturing apparatus used for the manufacturing method of the expandable polystyrene-type resin particle for roof bottom heat insulating material manufacture of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The method for producing expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention has a bromine atom in a molecule and a bromine content of less than 70% by mass in a polystyrene resin in a resin supply apparatus. A flame retardant / foaming agent-containing molten resin having a benzene ring in the molecule and adding and kneading a flame retardant and a foaming agent having a 5 mass% decomposition temperature within the range of 200 to 300 ° C. Is extruded into the cooling liquid directly from the small hole of the die attached to the tip of the resin supply device, and at the same time the extrudate is cut, the extrudate is cooled and solidified by contact with the liquid, and expandable polystyrene resin particles Without using an aromatic organic compound consisting of styrene monomer, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene, toluene, benzene. It is characterized by obtaining the foam polystyrene resin particles.

  FIG. 1 is a configuration diagram showing an example of a production apparatus used in the method for producing expandable polystyrene resin particles for producing an under-floor heat insulating material according to the present invention. The production apparatus of this example is an extruder as a resin supply apparatus. 1, a die 2 having a large number of small holes attached to the tip of an extruder 1, a raw material supply hopper 3 for introducing a resin raw material or the like into the extruder 1, and a foaming agent supply to the molten resin in the extruder 1 A high-pressure pump 4 for press-fitting a foaming agent through a port 5, a cutting chamber 7 provided so that cooling water is brought into contact with a resin discharge surface provided with a small hole in the die 2, and into which cooling water is circulated and supplied; The cutter 6 is rotatably provided in the cutting chamber 7 so that the resin extruded from the small hole of the die 2 can be cut, and the foamable particles carried along with the flow of cooling water from the cutting chamber 7 are cooled. Separation from water and dehydration A dehydrating dryer 10 with a solid-liquid separation function for drying to obtain expandable particles, a water tank 8 for storing cooling water separated by the dehydrating dryer 10 with a solid-liquid separation function, and the cooling water in the water tank 8 are cut. A high-pressure pump 9 for feeding to the chamber 7 and a storage container 11 for storing expandable particles dehydrated and dried by a dehydrator / dryer 10 with a solid-liquid separation function are provided.

  As the extruder 1, either an extruder using a screw or an extruder not using a screw can be used. Examples of the extruder using a screw include a single-screw extruder, a multi-screw extruder, a vent-type extruder, and a tandem extruder. Examples of the extruder that does not use a screw include a plunger type extruder and a gear pump type extruder. Moreover, any extruder can use a static mixer. Among these extruders, an extruder using a screw is preferable from the viewpoint of productivity. Moreover, the conventionally well-known thing used in the granulation method by melt extrusion of resin can also be used for the cutting chamber 7 which accommodated the cutter 6. FIG.

  In the expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, the polystyrene resin is not particularly limited. For example, styrene, α-methylstyrene, vinyltoluene, chlorostyrene, ethylstyrene, i-propylstyrene. Homopolymers of styrene monomers such as dimethyl styrene and bromo styrene or copolymers thereof, and the like. Polystyrene resins containing 50% by mass or more of styrene are preferable, and polystyrene is more preferable.

  Further, the polystyrene resin may be a copolymer of the styrene monomer and a vinyl monomer copolymerizable with the styrene monomer, the main component of which is the styrene monomer. As, for example, alkyl (meth) acrylate such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, cetyl (meth) acrylate, (meth) acrylonitrile, dimethyl maleate, dimethyl fumarate, diethyl In addition to fumarate and ethyl fumarate, bifunctional monomers such as divinylbenzene and alkylene glycol dimethacrylate are exemplified.

  If a polystyrene resin is the main component, other resins may be added. Examples of the resin to be added include polybutadiene, styrene-butadiene copolymer to improve the impact resistance of the foam molded article. Examples thereof include rubber-modified polystyrene resins to which a diene rubbery polymer such as a polymer, ethylene-propylene-nonconjugated diene three-dimensional copolymer is added, so-called high impact polystyrene. Alternatively, a polyethylene resin, a polypropylene resin, an acrylic resin, an acrylonitrile-styrene copolymer, an acrylonitrile-butadiene-styrene copolymer, and the like can be given.

  In the expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, as a polystyrene resin used as a raw material, a polystyrene system newly produced by a method such as a commercially available normal polystyrene resin or suspension polymerization method. In addition to a polystyrene-based resin (virgin polystyrene) that is not a recycled material, such as a resin, a recycled material obtained by regenerating a used polystyrene-based resin foam molding can be used. As this recycled material, used polystyrene-based resin foam moldings such as fish boxes, household appliance cushioning materials, food packaging trays, etc. are collected and recycled from the recycled materials recovered by the limonene dissolution method or heating volume reduction method. A raw material having a weight average molecular weight Mw in the range of 120,000 to 400,000 can be appropriately selected, or a plurality of recycled raw materials having different weight average molecular weights Mw can be used in appropriate combination.

In the expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, the flame retardant has a bromine atom in the molecule, a bromine content of less than 70% by mass, and a benzene ring in the molecule. In addition, a flame retardant having a 5 mass% decomposition temperature within the range of 200 to 300 ° C of the flame retardant is used, and one or more of the flame retardants are mixed, or the flame retardant is mainly used. As such, it may be used in combination with other flame retardants.
A flame retardant with a bromine content of more than 70% by mass and no benzene ring in the molecule is unlikely to be a flame retardant that is highly safe for the environment and organisms, and has excellent mechanical strength, moldability, and dimensional stability. Therefore, it is difficult to achieve the effect of the present invention that provides a heat insulating material under the roof. The lower limit of the bromine content is not particularly limited, but 50% by mass or more is preferable because the flame retardancy is good. A more preferable range of bromine content is 55 to 69 mass%.
Further, when the 5 mass% decomposition temperature of the flame retardant is less than 200 ° C., when the flame retardant and polystyrene resin are melt-kneaded in the extruder 1, the flame retardant decomposes and a flame retardant effect is obtained. There is a risk of disappearing. When a flame retardant having a 5 mass% decomposition temperature exceeding 300 ° C. is used, the flame retardance of the obtained under-floor heat insulating material is lowered. The preferable range of 5 mass% decomposition temperature of this flame retardant is 230-300 degreeC, The more preferable range is 240-295 degreeC, The most preferable range is 265-290 degreeC.

In the present invention, preferred flame retardants include one or more selected from the group consisting of tetrabromobisphenol A or derivatives thereof. Among these flame retardants, tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis (2,3-dibromopropyl ether), tetrabromobisphenol A- It is preferable that it is 1 type, or 2 or more types selected from the group consisting of bis (allyl ether). Tetrabromobisphenol A-bis (2,3-dibromopropyl ether) and tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) having a high 5% decomposition temperature are more preferred, and tetrabromobisphenol A- Bis (2,3-dibromopropyl ether) is most preferred.
In the expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, the amount of the flame retardant added is 0.5 to 100 parts by mass of the resin content of the expandable polystyrene resin particles for producing an under-roof heat insulating material. It is preferable to set it as the range of 8.0 mass%, and the range of 1.0-6.0 mass% is still more preferable. When the addition amount of the flame retardant is less than the above range, the flame resistance of the obtained under-floor heat insulating material is lowered. When the amount of the flame retardant added exceeds the above range, the mechanical strength, formability, and dimensional stability of the obtained under-floor heat insulating material may be deteriorated.

  In the expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, the foaming agent is not particularly limited. For example, normal pentane, isopentane, cyclopentane, cyclopentadiene, etc. are used alone or in combination of two or more. Can be used. Further, normal butane, isobutane, propane and the like can be mixed and used with the pentane as a main component. In particular, pentanes are preferably used because they easily suppress foaming of the resin particles when discharged into the water stream from the small holes of the die. The amount of the foaming agent contained in the polystyrene resin is in the range of 3 to 10 parts by mass, more preferably in the range of 4 to 7 parts by mass with respect to 100 parts by mass of the polystyrene resin.

  In addition to the flame retardant and the foaming agent, the foamable polystyrene resin particles for producing an under-floor heat insulating material according to the present invention may include other additives generally used in the production of expandable polystyrene resin particles. Agents, for example, talc, calcium silicate, synthetic or naturally produced silicon dioxide, ethylene bisstearic acid amide, methacrylic acid ester copolymer and other foam nucleating agents, diphenylalkane, diphenylalkene and other flame retardant aids, Colorants such as carbon black, iron oxide and graphite, phenolic antioxidants, sulfur antioxidants, antioxidants such as phosphorus antioxidants, stabilizers such as hindered amines, UV absorbers, antioxidants, etc. These additives can be added to the polystyrene resin.

  In order to produce the expandable polystyrene resin particles for the production of the under-the-air insulation material of the present invention using the production apparatus shown in FIG. 1, first, the raw material polystyrene resin, the flame retardant, the foam nucleating agent, and as necessary. The desired additive to be added is weighed and charged into the extruder 1 from the raw material supply hopper 3. The raw polystyrene resin may be pelletized or granulated and mixed well in advance and then fed from one raw material supply hopper. For example, when multiple lots are used, the supply amount for each lot may be reduced. A plurality of adjusted raw material supply hoppers may be charged and mixed in an extruder. Also, when using a combination of recycled materials from multiple lots, mix the raw materials from multiple lots in advance and remove foreign matter using appropriate sorting methods such as magnetic sorting, sieving, specific gravity sorting, and air blowing sorting. It is preferable to keep it.

  In a preferred embodiment of the present invention, when the flame retardant is added, a masterbatch material containing a flame retardant at a predetermined concentration in the resin is used, and this is supplied into the resin supply apparatus together with the polystyrene-based resin. It is preferable to melt and knead. A master batch material containing the flame retardant at a predetermined concentration in the resin is supplied into the resin supply apparatus together with the polystyrene resin, and melt-kneaded in the apparatus so that the flame retardant is more uniformly contained in the resin particles. Can do.

  After supplying polystyrene-based resin and flame retardant, further foaming aid and other additives into the extruder 1, the resin is heated and melted, and the flame retardant-containing molten resin is transferred to the die 2 side while supplying the foaming agent supply port. The foaming agent is press-fitted with a high-pressure pump 4 from 5, the foaming agent is mixed with the flame retardant-containing molten resin, and the melt is further kneaded through a foreign matter removing screen provided in the extruder 1 as necessary. The melted material added with the blowing agent is pushed out from the small hole of the die 2 attached to the tip of the extruder 1.

  The resin discharge surface in which the small holes of the die 2 are drilled is disposed in the cutting chamber 7 in which cooling water is circulated and supplied into the chamber, and the resin extruded from the small holes of the die 2 is placed in the cutting chamber 7. A cutter 6 is provided so as to be rotatable. Extruding the melt with the blowing agent added through a small hole in the die 2 attached to the tip of the extruder 1 causes the melt to be cut into granules, and at the same time, brought into contact with cooling water and rapidly cooled to solidify while suppressing foaming. Thus, expandable polystyrene-based resin particles for producing an under-floor insulation material are obtained.

  The formed expandable polystyrene resin particles for manufacturing an under-the-floor heat insulating material are transferred from the cutting chamber 7 to the flow of the cooling water and carried to the dehydrating dryer 10 with a solid-liquid separation function. The expandable polystyrene resin particles are separated from the cooling water and dehydrated and dried. The dried expandable polystyrene-based resin particles for producing an under-floor heat insulating material are stored in the storage container 11.

  The expandable polystyrene resin particles for manufacturing an under-the-sheath insulating material manufactured as described above are in the form of particles of a polystyrene resin containing a flame retardant and a foaming agent, and the flame retardant has a bromine atom in the molecule. The bromine content is less than 70 mass%, the molecule has a benzene ring, and the 5 mass% decomposition temperature of the flame retardant is in the range of 200 to 300 ° C.

  In the expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, the flame retardant is uniformly contained in the resin particles. In the expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention, if not uniformly contained, the mechanical strength, moldability, dimensional stability and flame retardancy of the obtained foamed molded body (under-the-roof heat insulating material) are obtained. May be inferior.

The flame retardant used in the expandable polystyrene resin particles for producing an under-floor heat insulating material according to the present invention has high safety to the environment and living organisms. In particular, the tetrabromobisphenol A derivative is applied to a polystyrene resin foam molded article. When added, it can provide sufficient flame retardancy and is highly safe for the environment and organisms.
The expandable polystyrene resin particles for producing an under-floor heat insulating material of the present invention are obtained in comparison with those in which the flame retardant is uniformly present in the resin particles and the flame retardant is non-uniformly present in the resin particles. The mechanical strength of the flame-retardant polystyrene-based resin foam molded article to be obtained is increased, and an under-roof heat insulating material excellent in moldability and dimensional stability can be obtained.

  In the production method according to the present invention, a resin raw material having a low content of an aromatic organic compound composed of a styrene monomer, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene, toluene, and benzene is selected as a polystyrene resin as a raw material. For example, the expandable polystyrene resin particles can be obtained without mixing the aromatic organic compound in the manufacturing process. The total content of the compound can be less than 500 ppm. The total content of the aromatic organic compound is more preferably 450 ppm or less, and still more preferably 400 ppm or less. If the total content of the aromatic organic compound is low, it is possible to cope with sick house syndrome, which has been recently requested, and it is suitable for use in the production of a heat insulating material under a roof.

In the present invention, the total content of the aromatic organic compound is a value measured by the following <Measurement method of volatile organic compound (VOC) content>.
<Measurement method of volatile organic compound (VOC) content>
Weigh accurately 1 g of expandable polystyrene resin particles, add 1 ml of a dimethylformamide solution containing 0.1% by volume of cyclopentanol as an internal standard solution, and then add dimethylformamide to the dimethylformamide solution to measure 25 ml. A solution was prepared, and 1.8 μl of this measurement solution was supplied to a 230 ° C. sample vaporization chamber to obtain a chart of each volatile organic compound detected by a gas chromatograph. And based on the calibration curve of each volatile organic compound measured beforehand, the amount of volatile organic compounds was calculated from each chart, and the amount of volatile organic compounds in the expandable polystyrene resin particles was calculated.
In the present invention, among the volatile organic compound (VOC) contents described above, the total amount of each volatile organic compound corresponding to the aromatic organic compound is defined as “total amount of aromatic organic compound”.

The expandable polystyrene-based resin particles for producing an under-floor heat insulating material obtained by the production method according to the present invention described above are preliminarily heated by steam heating or the like using a well-known apparatus and method in the production field of foamed resin molded bodies. It expands and it is set as the pre-expanded particle (henceforth a pre-expanded particle) for roof bottom heat insulating material manufacture. The pre-expanded particles are pre-expanded so as to have a bulk density equivalent to the density of the foamed molded product to be manufactured. In the present invention, its bulk density is not limited, usually in the range of 0.010~0.050g / cm ^3, preferably in the range of 0.015~0.025g / cm ^3.

In the present invention, the bulk density of the pre-expanded particles is measured as follows.
<Bulk density and bulk expansion ratio of pre-expanded particles>
First, Wg was sampled from pre-expanded particles as a measurement sample, and this measurement sample was allowed to fall naturally into a graduated cylinder, and then the apparent volume (V) cm ³ of the sample was made constant by tapping the bottom of the graduated cylinder. And the volume is measured, and the bulk density of the pre-expanded particles is measured based on the following formula.
Bulk density (g / cm ³ ) = mass of measurement sample (W) / volume of measurement sample (V)
The bulk expansion ratio of the pre-expanded particles is a numerical value calculated by the following formula.
Bulk foam multiple (times) = 1 / bulk density (g / cm ³ )

The pre-expanded particles can be obtained by filling the pre-expanded particles into a cavity of a molding die using a well-known apparatus and technique in the field of manufacturing a foamed resin molded body, and heating them by steam heating or the like to perform in-mold foam molding. Manufactures an under-the-sheath insulating material made of a flame-retardant polystyrene-based resin foam molding.
Although the density of the roof under the heat insulating material of the present invention is not particularly limited, usually in the range of 0.010~0.050g / cm ^3, preferably in the range of 0.015~0.025g / cm ³ .

In addition, the density of the base material for roofs in this invention is a foaming molding density measured by the method of JISK7122: 1999 "Measurement of foamed plastic and rubber-apparent density".
<Density and expansion ratio of foamed molded product>
A test piece of 50 cm ³ or more (100 cm ³ or more in the case of semi-rigid and soft materials) was cut so as not to change the original cell structure of the material, its mass was measured, and calculated by the following formula.
Density (g / cm ³ ) = Test piece mass (g) / Test piece volume (cm ³ )
Test piece condition adjustment and measurement test pieces were cut out from samples that had passed 72 hours or more after molding, and were subjected to atmospheric conditions of 23 ° C. ± 2 ° C. × 50% ± 5% or 27 ° C. ± 2 ° C. × 65% ± 5%. It has been left for more than an hour.
Further, the expansion factor of the foamed molded product is a numerical value calculated by the following equation.
Foaming multiple (times) = 1 / density (g / cm ³ )

In the under-roof heat insulating material of the present invention, the foamed molded body having a foaming ratio of 50 times preferably has an average chord length of bubbles in the range of 50 to 350 μm, and more preferably in the range of 60 to 300 μm. In addition, in this invention, the average chord length of a bubble is an average chord length of the bubble of a foaming molding measured by the following method.
<Average string length>
The average chord length of the bubbles of the foam molded article refers to that measured according to the test method of ASTM D2842-69. Specifically, the foamed molded body is cut into approximately equal halves, and the cut surface is photographed at a magnification of 100 times using a scanning electron microscope (trade name “S-3000N” manufactured by Hitachi, Ltd.). The photographed image is printed on A4 paper, and a straight line having a length of 60 mm is drawn at an arbitrary position, and the average chord length (t) of the bubbles is calculated from the following formula from the number of bubbles existing on the straight line.
Average string length t = 60 / (number of bubbles × photo magnification)
When drawing a straight line, if the straight line is in point contact with the bubble, this bubble is included in the number of bubbles, and both ends of the straight line are not penetrating the bubble and are in the bubble. In this case, the bubbles in which both ends of the straight line are positioned are included in the number of bubbles. Further, the average chord length is calculated in the same manner as described above at any five locations in the photographed image, and the arithmetic mean value of these average chord lengths is set as the average chord length of the bubbles of the foam molded body.

[Example 1]
(Manufacture of expandable polystyrene resin particles)
As a base resin, a polystyrene resin (manufactured by Toyo Styrene Co., Ltd., trade name “HRM-10N”) and a styrene-methacrylic acid copolymer resin (manufactured by Toyo Styrene Co., Ltd., trade name “T-080”) are used at a mass ratio of 50:50. Polystyrene resin masterbatch 7 containing 50% by mass of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) (Daiichi Kogyo Seiyaku Co., Ltd.) as a flame retardant with respect to 100 parts by mass of the blended resin. A single shaft having a diameter of 90 mm at a rate of 160 kg / hr per hour is obtained by uniformly mixing mass parts (equivalent to 3.5 parts by mass of flame retardant) and 0.3 parts by mass of fine powder talc in advance with a tumbler mixer. After feeding into the extruder and heating and melting the resin, 6 parts by mass of isopentane was injected from the middle of the extruder as a foaming agent with respect to 100 parts by mass of the resin. Then, while kneading the resin and the foaming agent in the extruder, while cooling so that the resin temperature at the tip of the extruder is 190 ° C., it is connected to the extruder and held at 320 ° C. by a heater, diameter 0.6 mm Then, through a granulation die having 200 nozzles with a land length of 3.0 mm, it is extruded into a chamber in which cooling water at 50 ° C. circulates, and at the same time, a high-speed rotary cutter having 10 blades in the circumferential direction is used as the die. Adhered, cut at 3000 rpm, dehydrated and dried to obtain spherical expandable polystyrene resin particles. The obtained expandable polystyrene resin particles had no deformation, no whiskers, and the average particle size was 1.1 mm.
Polyethylene glycol 0.03 parts by mass, zinc stearate 0.15 parts by mass, stearic acid monoglyceride 0.05 parts by mass, hydroxystearic acid triglyceride 0.05 parts by mass with respect to 100 parts by mass of the obtained expandable polystyrene resin particles. The part was uniformly coated on the entire surface of the expandable polystyrene resin particles.

(Manufacture of foam moldings)
The expandable polystyrene resin particles produced as described above were placed in a 15 ° C. cool box and allowed to stand for 72 hours, then supplied to a cylindrical batch type pre-foaming machine, and steam with a blowing pressure of 0.1 MPa. To obtain pre-expanded particles. The obtained pre-expanded particles had a bulk density of 0.020 g / cm ³ (bulk expansion ratio: 50 times). Subsequently, the pre-expanded particles obtained were allowed to stand at room temperature for 24 hours, and then the pre-expanded particles were filled into a mold having a rectangular cavity of length 400 mm × width 300 mm × height 25 mm. Thereafter, the inside of the mold cavity is heated with water vapor at a gauge pressure of 1.0 MPa for 20 seconds, and then cooled until the pressure in the mold cavity becomes 0.15 MPa, and then the mold is Opened, a rectangular foam molded body having a length of 400 mm, a width of 300 mm, and a height of 50 mm was taken out. The obtained foamed molded article had a density of 0.020 g / cm ³ (molding factor: 50 times).

  The following evaluation tests were performed on the expandable polystyrene resin particles, pre-expanded particles, and expanded molded articles of Example 1 produced as described above.

<Measurement of flame retardant decomposition temperature>
20 mg of flame retardant was sampled and used as a sample, using a differential heat and calorie simultaneous measurement device TG / DTA 300 (Seiko Electronics Co., Ltd.), nitrogen gas amount 30 ml / min, heating temperature 10 ° C./min, measurement temperature The mass reduction rate of the sample is measured under the conditions of 30 to 800 ° C., and a graph is obtained with the mass reduction rate of the sample on the vertical axis and the temperature on the horizontal axis. And based on the obtained graph, the temperature when the mass reduction rate of the sample reached 5% was defined as a 5 mass% decomposition temperature.

<Measurement of volatile organic compound (VOC) content in expandable polystyrene resin particles>
Weigh accurately 1 g of expandable polystyrene resin particles, add 1 ml of a dimethylformamide solution containing 0.1% by volume of cyclopentanol as an internal standard solution, and then add dimethylformamide to the dimethylformamide solution to measure 25 ml. A solution was prepared, and 1.8 μl of this measurement solution was supplied to a 230 ° C. sample vaporization chamber, and each volatile organic compound detected by a gas chromatograph (manufactured by Shimadzu Corporation, trade name “GC-14A”) under the following measurement conditions. Based on the calibration curve of each volatile organic compound measured in advance, the amount of volatile organic compound was calculated from each chart, and the volatile organic compound in the expandable polystyrene particles was obtained. The amount was calculated.
Detector: FID
Column: GL Sciences (3mmφ × 2.5m)
Liquid phase: PEG-20M PT 25%
Carrier; Chromosorb W AW-DMCS
Mesh: 60/80
Column temperature: 100 ° C
Detector temperature: 230 ° C
DET temperature: 230 ° C
Carrier gas (nitrogen)
Carrier gas flow rate (40ml / min)

<Evaluation of bead foamability>
After the expandable polystyrene resin particles obtained in Examples (and Comparative Examples) were stored in a 15 ° C. cool box for 72 hours, they were supplied to a cylindrical batch type pre-foaming machine, and the blowing vapor pressure was 0.1 MPa. The pre-expanded particles obtained were heated for 3 minutes with water vapor and the bulk expansion ratio of the pre-expanded particles was measured as follows, and the following evaluation criteria:
The bulk foaming factor is 50 times or more.
A bulk foaming ratio of 40 times or more and less than 50 times is Δ,
The foam foaming property was evaluated by evaluating the foam foaming factor of less than 40 times with x.

<Flame retardance>
Cut foam from the molded body of 200 mm × 25 mm × 10 mm size of the test sample 5 a in vertical cutter, after 1 day aging at 60 ° C. oven was measured according to measurement method A of JISA9511 _-2006, five of The average value was determined and used as the extinguishing time. In this JIS standard, the flame extinguishing time must be within 3 seconds, more preferably within 2 seconds, and even more preferably within 1 second.
○ (Acceptance) ... The flame extinguishing time is within 3 seconds, and all five samples have no residue and do not burn beyond the combustion limit indicator line.
X (failure) ... The flame extinguishing time exceeds 3 seconds, or even one of the samples has residue, or burns beyond the combustion limit indicating line.

<Appearance evaluation of foam molding>
The polystyrene resin pre-expanded particles were filled into a mold of a foam molding machine and subjected to secondary foaming using water vapor to obtain a rectangular foam-shaped foam molded body having a length of 400 mm, a width of 300 mm, and a thickness of 50 mm.
The appearance of the foamed molded product was visually observed and evaluated based on the following criteria.
A (very good): There is no gap between the expanded particles, and the surface is very smooth.
○ (good): There is no gap between the expanded particles, and the surface is smooth.
Δ (slightly good): There are few gaps between the expanded particles, and the surface smoothness is slightly inferior.
X (Poor): The gap between the expanded particles is large, and the smoothness of the surface is considerably inferior.

<Heating dimensional change rate>
A flat foam molded body having a length of 400 mm, a width of 300 mm, and a thickness of 25 mm is taken out of the mold and left in a constant temperature and humidity chamber (standard temperature and humidity state of JIS-K7100) at a temperature of 23 ° C. and a relative humidity of 50% for 24 hours. After that, a square flat plate (length: 150 mm, width: 150 mm, thickness: 25 mm) is cut out from the center portion of the foamed molded body in parallel with each other in the vertical and horizontal directions. A straight line was written at intervals of 50 mm to obtain a test piece according to JIS-K6767. After measuring the dimensions of this test piece (dimension before heating: L2), place it horizontally in a hot air circulating dryer maintained at 90 ° C., heat it for 168 hours, take it out, and again leave it in a constant temperature and humidity room for 1 hour. Then, the dimension of the test piece (dimension after heating: L2) was measured. The dimensional measurement before and after the heating test was performed according to JIS-K6767, and the dimensional change rate was determined according to the following equation.
Dimensional change rate (%) = (L2-L1) × 100 / L1
(However, L1 is the size of the test piece obtained from the foamed molded product that was allowed to stand for 24 hours at 23 ° C. and 50% relative humidity after in-mold molding, and L2 is the value after heating the molded product at 90 ° C. for 168 hours. It is the size of the test piece)
In addition, a dimension is the average value of the length of three straight lines each written in the test piece obtained from the foaming molding.
The heating dimensional change rate is -0.5% or more, less than + 0.5% is good (◯), -1.0% or more, less than -0.5% is slightly good (Δ), + 0.5% or more, Less than + 1.0% was evaluated as slightly good (Δ), less than −1.0% was evaluated as defective (×), and + 1.0% or more was evaluated as defective (×).

<Comprehensive evaluation>
For each evaluation item of <Bead Foaming Evaluation>, <Flame Retardancy>, <Appearance Evaluation of Foam Molded Product>, and <Heating Dimension Change Rate> Those having one or more defects (x) were comprehensively evaluated as defects (x).

[Example 2]
As the flame retardant, foam molding of 50 times expansion ratio was performed in the same manner as in Example 1 except that the same amount of tetrabromobisphenol A-bis (2,3-dibromopropyl ether) (Daiichi Kogyo Seiyaku Co., Ltd.) was used. The body was manufactured.

[Example 3]
As a flame retardant, a foamed molded article having a 50-fold expansion ratio was produced in the same manner as in Example 1 except that the same amount of tetrabromobisphenol A-bis (allyl ether) (Daiichi Kogyo Seiyaku Co., Ltd.) was used.

[Example 4]
Except that 3.2 parts by mass of tetrabromobisphenol A-bis (2,3-dibromopropyl ether) and 0.3 parts by mass of tetrabromobisphenol A-bis (allyl ether) were used as flame retardants, In the same manner as in Example 1, a foamed molded article having a expansion ratio of 50 times was produced.

[Comparative Example 1]
A foamed molded article was produced in the same manner as in Example 1 except that the same amount of hexabromocyclododecane (Daiichi Kogyo Seiyaku Co., Ltd.) was used as the flame retardant.

[Comparative Example 2]
A foamed molded article was produced in the same manner as in Example 1 except that the same amount of tris- (2,3-dibromopropyl) isocyanurate (Nihon Kasei Co., Ltd.) was used as the flame retardant.

[Comparative Example 3]
A foamed molded article was produced in the same manner as in Example 1 except that the same amount of pentabromobenzyl acrylate (Daiichi Kogyo Seiyaku Co., Ltd.) was used as the flame retardant.

[Comparative Example 4]
A foamed molded article was produced in the same manner as in Example 1 except that the same amount of tris (tribromoneopentyl) phosphate (manufactured by Daihachi Chemical Co., Ltd.) was used as a flame retardant.

Table 1 summarizes the bromine content of the flame retardants used in Examples 1 to 4 and Comparative Examples 1 to 4, the presence or absence of a benzene ring in the flame retardant molecule, and the 5 mass% decomposition temperature.
The measurement and evaluation results of Examples 1 to 4 and Comparative Examples 1 to 4 are collectively shown in Table 2.

From the results of Tables 1 and 2, the examples have bromine atoms in the molecule, the bromine content is less than 70% by mass, the molecule has a benzene ring, and the flame retardant has a 5% by mass decomposition temperature. Examples 1 to 4 according to the present invention using flame retardants A to C in the range of 200 to 300 [deg.] C. are not limited in bead foamability, flame retardancy, appearance of the foamed molded product, and heating dimensional change rate. Was also good.
On the other hand, Comparative Example 1 using the flame retardant D having a high bromine content of 75% by mass and having no benzene ring in the molecule had poor bead foaming properties.
In Comparative Example 2 using the flame retardant E having no benzene ring in the molecule, the bead foaming property and the appearance of the foamed molded product were poor.
Further, Comparative Example 3 using the flame retardant F having a high bromine content of 75% by mass and a 5% by mass decomposition temperature exceeding 300 ° C. was poor in flame retardancy and heating dimensional change rate.
Comparative Example 4 using a flame retardant G having a high bromine content of 75% by mass, no benzene ring in the molecule and a 5% by mass decomposition temperature exceeding 300 ° C. The appearance of the foam was poor.

  TECHNICAL FIELD The present invention relates to an underfloor heat insulating material excellent in environmental compatibility and flame retardancy, an expandable polystyrene resin particle for producing an under roof heat insulating material used in the manufacture thereof, and a method for producing the same. The underfloor heat insulating material of the present invention is used, for example, as a heat insulating material laid between a base material such as a field board and a roofing material.

  DESCRIPTION OF SYMBOLS 1 ... Extruder (resin supply apparatus), 2 ... Die, 3 ... Raw material supply hopper, 4 ... High pressure pump, 5 ... Foam supply port, 6 ... Cutter, 7 ... Cutting chamber, 8 ... Water tank, 9 ... High pressure pump, 10: Dehydration dryer with solid-liquid separation function, 11: Storage container.

Claims (11)

Expandable polystyrene resin particles for the production of under-floor heat insulating material, which are made into a particulate polystyrene resin containing a flame retardant and a foaming agent,
The flame retardant has a bromine atom in the molecule, a bromine content of less than 70% by mass, a benzene ring in the molecule, and a 5% by mass decomposition temperature of the flame retardant of 200 to 300 ° C. Within the range of
A flame retardant and foaming agent are added to and kneaded with polystyrene resin in the resin supply device, and the molten resin containing the flame retardant / foaming agent is extruded directly into the cooling liquid through a small hole in the die attached to the tip of the resin supply device. A heat insulating material under roof characterized by being obtained by a melt extrusion method in which extrudates are cut simultaneously with extrusion and the extrudates are cooled and solidified by contact with a liquid to obtain expandable polystyrene resin particles. Expandable polystyrene resin particles for production.   The expandable polystyrene resin particles for producing an under-the-air insulation material according to claim 1, wherein the total content of aromatic organic compounds comprising styrene monomer, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene, toluene, benzene is less than 500 ppm. .   The expandable polystyrene resin particles for manufacturing an under-the-air insulation material according to claim 1 or 2, wherein the flame retardant is one or more selected from the group consisting of tetrabromobisphenol A or a derivative thereof.   The flame retardant is tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis (2,3-dibromopropyl ether), tetrabromobisphenol A-bis (allyl ether) The expandable polystyrene resin particles for producing an under-the-sheath insulating material according to any one of claims 1 to 3, wherein the expandable polystyrene resin particles are one or more selected from the group consisting of:   The pre-expanded particle for roof under heat insulation manufacture obtained by heating the expandable polystyrene-type resin particle for roof under heat insulation manufacture of any one of Claims 1-4. A roof having a density in the range of 0.010 to 0.050 g / cm ³ obtained by filling the pre-expanded particles for producing an under-sheath insulating material according to claim 5 into a cavity of a mold, heating and foaming. Lower insulation material.   The pre-expanded particles for producing an under-the-air insulation material according to claim 5 are filled in a cavity of a mold, heated and foamed, and the foamed molded body having a foam expansion factor of 50 times has an average cell string length of 50. Under roof insulation that is in the range of ~ 350 μm.   In the resin feeder, the polystyrene-based resin has a bromine atom in the molecule, a bromine content of less than 70% by mass, a benzene ring in the molecule, and a 5% by mass decomposition temperature of the flame retardant. Add and knead the flame retardant and foaming agent in the range of 200 to 300 ° C., and add the flame retardant / foaming agent-containing molten resin directly into the cooling liquid from the small hole of the die attached to the tip of the resin feeder In the method of extruding, cutting the extrudate at the same time as extrusion, and cooling and solidifying the extrudate by contact with a liquid to produce expandable polystyrene resin particles, styrene monomer, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene Expandable polystyrene-based resin particles for the production of a thermal insulation material under roofs according to claim 1 or 2, without using an aromatic organic compound comprising toluene, benzene Method of manufacturing a roofing under thermal insulator for producing expandable polystyrene resin particles characterized by obtaining.   The method for producing expandable polystyrene resin particles for producing an under-the-air insulation material according to claim 8, wherein the flame retardant is one or more selected from the group consisting of tetrabromobisphenol A or a derivative thereof.   The flame retardant is tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis (2,3-dibromopropyl ether), tetrabromobisphenol A-bis (allyl ether) The method for producing expandable polystyrene resin particles for producing an under-floor heat insulating material according to claim 9, which is one or more selected from the group consisting of:   The underbath according to any one of claims 8 to 10, wherein a master batch material containing the flame retardant at a predetermined concentration in a resin is supplied into a resin supply apparatus together with the polystyrene resin, and is melt-kneaded in the apparatus. The manufacturing method of the expandable polystyrene-type resin particle for heat insulating material manufacture.

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