JP2012136675A - Styrene-based resin extrusion foam body, and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a styrene-based resin extrusion foam body excellent in non-combustibility, heat insulating property and thermal stability.SOLUTION: The styrene-based resin extrusion foam body is obtained by heating and melting a styrene-based resin and adding a foaming agent thereto followed by extrusion foaming. The foam body contains, based on 100 pts.wt. of the styrene-based resin, 1-6 pts.wt. of a mixed bromine-based flame retarder, 0.1-10 pts.wt. of a nitrogen-containing compound, and 0.1-10 pts.wt. of a phosphate-based compound. The mixed bromine-based flame retarder is composed of (A) tetrabromobisphenol-A-bis(2,3-dibromo-2-methylpropylether) and tetrabromobisphenol-A-bis(2,3-dibromopropylether), or of (B) tetrabromobisphenol-A-bis(2,3-dibromo-2-methylpropylether) and tris(2,3-dibromopropyl)isocyanurate. The content of tetrabromobisphenol-A-bis(2,3-dibromo-2-methylpropylether) is 25-75 wt.% relative to 100 wt.% of the entire mixed bromine-based flame retarder.

Description

  The present invention relates to a styrene resin foam excellent in flame retardancy and excellent in heat insulation and thermal stability, and a method for producing the same.

  A method of continuously producing a foam by melting a styrene resin with an extruder or the like, then adding a foaming agent, cooling it, and extruding it into a low pressure region is already known (for example, patents). In order to satisfy the flammability standard of the extruded styrene foam heat insulating plate described in Document 1, Patent Document 2) and JIS A9511, a flame retardant is added.

As a main requirement of the flame retardant suitable for the styrene resin extruded foam, first, it is required that the flame retardant does not decompose at around 230 ° C., which is a general polystyrene extrusion temperature. If the flame retardant decomposes, it has adverse effects such as deterioration in flame retardant performance, poor appearance of the foam, poor molding, or difficulty in controlling the foam cell diameter.
Another necessary condition suitable for the styrene resin extruded foam is that the flame retardant decomposes efficiently before the decomposition of polystyrene. Generally, it is known that polystyrene decomposes from around 300 ° C. If the flame retardant does not decompose efficiently at a temperature lower than this temperature, there is a possibility that the flammability standard described in JIS A9511 may not be satisfied. Alternatively, in order to obtain the required flame retardancy, the number of added parts must be increased as a result, and there is a tendency to adversely affect the product cost and the moldability of the resulting foam.

  Therefore, hexabromocyclododecane (hereinafter abbreviated as HBCD) has been widely used as the flame retardant. HBCD is known to be relatively stable under extrusion conditions and to be efficiently decomposed when polystyrene is decomposed, and can exhibit high flame retardancy with a small number of added parts.

  On the other hand, HBCD is a non-degradable and highly bioaccumulative compound, so it is not preferable for environmental hygiene, and it is desired to reduce the amount of HBCD used and to develop a flame retardant that replaces HBCD. .

  Then, examination of the styrene resin extrusion foam using brominated flame retardants other than HBCD is made.

In recent years, tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) has been proposed as a flame retardant instead of HBCD.
Tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) has a flame retardancy of almost the same level as HBCD, but has a problem in thermal stability and requires the addition of a stabilizer. However, as shown in Patent Document 3, when a metal salt of a higher fatty acid is used as a stabilizer, the thermal stability is improved, but the flame retardancy is reduced, and the inherently difficult flame retardant has. There is a problem that the fuel performance is not exhibited. Also. As an example of application to a styrene resin, Patent Document 4 proposes a method of adding an organic solvent solution, but the used solvent is not left in the product but is scattered outside the system. It's not a good way.

  On the other hand, tetrabromobisphenol-A-bis (2,3-dibromopropyl ether), tris (2,3-dibromopropyl) isocyanurate and the like have also been proposed as flame retardants that have recently changed to HBCD, as described in Patent Document 5. However, it is insufficient for obtaining flame retardancy by itself, and combined use with tetrabromobisphenol allyl ether or tribromophenol allyl ether has been proposed. However, when the allyl ether compound is blended in an amount necessary to express the required flame retardancy, the thermal stability is extremely deteriorated, and even if various stabilizers are added, it is not sufficiently improved.

In recent years, saturated hydrocarbon compounds such as propane and butane are often used as blowing agents in place of Freon from the viewpoint of protecting the ozone layer.
For example, in order to obtain a foam having high heat insulation properties such as three types of extruded polystyrene foam heat insulating plates specified in JIS A9511, it is preferable to leave a larger amount of the foaming agent. Depending on the body density, if the foam density is in the range of 20-40 kg / m 3, 4.0% by weight or more for propane and 2.5% for butanes relative to the weight of the foam. It is considered that it is preferable to leave at least 3.0% by weight of butanes. However, when a large amount of relatively flammable compounds such as aliphatic hydrocarbons typified by propane and butane remain, the flame retardancy specified in JIS A9511 may not be satisfied. On the other hand, in order to improve the flame retardancy, it is conceivable to increase the amount of the flame retardant to be added, but it is difficult to obtain a stable flame retardancy simply by increasing the amount of addition. In particular, although the styrene resin itself, which is the basic material of the foam, is flame retardant, the tendency that it is easy to ignite hydrocarbons that volatilize from the foam during combustion and it is difficult to suppress combustion is still difficult to solve. Furthermore, an increase in the amount of the flame retardant tends to cause deterioration in foam moldability, and it tends to be difficult to obtain a molded product with satisfactory quality.

  Thus, there is still room for improvement in the technology that can satisfy the flame retardancy, thermal stability, and processing stability of the styrene-based extruded foam.

Japanese Patent Publication No.31-5393 Japanese Patent Publication No.42-19195 Japanese Patent Publication No.51-25061 Japanese Patent Publication No.05-67654 Japanese Patent Laid-Open No. 2003-301064

  The present invention has been made in order to solve the above-mentioned problems of a styrene resin extruded foam, and provides a styrene resin extruded foam excellent in flame retardancy and thermal stability, and a method for producing the same. With the goal.

As a result of intensive studies to solve the above problems, the present inventors have found that flame retardancy with excellent environmental compatibility can be obtained by using a specific mixed brominated flame retardant. However, there is room for improvement in reducing the combustibility due to the ignition of the hydrocarbons from the foam.
In the production of styrenic resin foams using hydrocarbons as blowing agents, mixed brominated flame retardants (A) tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tetra Mixed brominated flame retardant composed of bromobisphenol-A-bis (2,3-dibromopropyl ether), or
(B) a mixed brominated flame retardant composed of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tris (2,3-dibromopropyl) isocyanurate; By using a specific amount of a phosphate ester compound, excellent flame retardancy can be achieved despite the use of a compound containing saturated hydrocarbons as a foaming agent. It has been found that the ignition or combustion of hydrogen can be suppressed, thereby making it possible to achieve both high flame retardancy as defined in JIS A9511 and high thermal stability.

That is, the present invention
[1] A styrene resin foam obtained by heating and melting a styrene resin, adding a foaming agent, and extruding and foaming the foaming agent,
Containing 1 to 6 parts by weight of mixed brominated flame retardant with respect to 100 parts by weight of styrene resin,
Further, 0.1 to 10 parts by weight of a nitrogen-containing compound and 0.1 to 10 parts by weight of a phosphate ester compound are contained,
The mixed brominated flame retardant is
(A) a mixed brominated flame retardant comprising tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tetrabromobisphenol-A-bis (2,3-dibromopropyl ether), or
(B) a mixed brominated flame retardant composed of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tris (2,3-dibromopropyl) isocyanurate;
And when the content of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) in the mixed brominated flame retardant is 100% by weight based on the total mixed brominated flame retardant, The present invention relates to a styrene resin extruded foam characterized by being 25% to 75% by weight.
[2] When the content of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) in the mixed brominated flame retardant is 100% by weight based on the total mixed brominated flame retardant, The styrene-based resin extruded foam according to [1], which is 35% by weight to 65% by weight.
[3] The styrene resin extruded foam according to [1] or [2], wherein the nitrogen-containing compound is isocyanuric acid and / or bis (2-carboxyethyl) isocyanurate.
[4] The extruded styrene resin foam according to any one of [1] to [3], wherein the phosphate ester compound is trimethyl phosphate.
[5] The styrenic resin foam according to any one of [1] to [4], wherein the foaming agent contains at least one selected from saturated hydrocarbons having 3 to 5 carbon atoms. About the body.
[6] The foaming agent further contains at least one selected from the group consisting of water, carbon dioxide, nitrogen, alcohols having 2 to 5 carbon atoms, dimethyl ether, methyl chloride, and ethyl chloride. It relates to the styrenic resin foam according to any one of [1] to [5].
[7] In the combustion measurement specified in JIS A9511, the flame is extinguished within 3 seconds, there is no residue, it does not burn beyond the combustion limit indicator line, and the flame retardant satisfies the condition that the oxygen index is 26% or more It has a performance, It is related with the styrene resin foam in any one of [1]-[6].
[8] The styrenic resin foam according to any one of [1] to [7], which has a heat insulation performance of 0.028 W / mK or less in the thermal conductivity measurement specified in JIS A9511. About.
[9] A method for producing a styrene resin foam obtained by heating and melting a styrene resin, adding a foaming agent, and extrusion-foaming the foam.
Containing 1 to 6 parts by weight of mixed brominated flame retardant with respect to 100 parts by weight of styrene resin,
Furthermore, 0.1 to 10 parts by weight of a nitrogen-containing compound, 0.1 to 10 parts by weight of a phosphate ester compound,
The mixed brominated flame retardant is
(A) a mixed brominated flame retardant comprising tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tetrabromobisphenol-A-bis (2,3-dibromopropyl ether), or
(B) a mixed brominated flame retardant composed of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tris (2,3-dibromopropyl) isocyanurate;
And when the content of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) in the mixed brominated flame retardant is 100% by weight based on the total mixed brominated flame retardant, The present invention relates to a method for producing a styrene-based resin extruded foam, which is 25% by weight to 75% by weight.

  According to the present invention, a styrene resin foam excellent in flame retardancy, thermal stability, and processing stability can be stably produced even when a material containing a saturated hydrocarbon is used as a foaming agent. It becomes possible. The styrenic resin foam of the present invention is particularly useful for use as a heat insulating material for construction due to its excellent performance.

  The styrenic resin used in the present invention is not particularly limited, and is obtained from a styrene homopolymer obtained only from a styrene monomer; a monomer copolymerizable with styrene monomer and styrene, or a derivative thereof. Random, block or graft copolymers; post-brominated polystyrene, modified polystyrene such as rubber reinforced polystyrene, and the like. These can be used alone or in admixture of two or more.

  Examples of monomers copolymerizable with styrene include styrene derivatives such as methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene; Polyfunctional vinyl compounds such as divinylbenzene; (meth) acrylic compounds such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, and acrylonitrile; Diene compounds or derivatives thereof; unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride. These can be used alone or in admixture of two or more.

  Among the styrene resins, styrene homopolymers, styrene acrylonitrile copolymers, (meth) acrylic acid copolymer polystyrene, maleic anhydride-modified polystyrene, impact-resistant polystyrene, and the like are preferable from the viewpoint of extrusion foam moldability and the like. Styrene homopolymer is more preferable from the viewpoint of cost.

  The styrene resin that can be used in the present invention is not limited to virgin resin, and recycled styrene resin can also be used. Examples include fish box EPS, home appliance cushioning materials, styrene resin foams such as food foam polystyrene trays, or polystyrene trays as refrigerator interior materials. Separately from this, a styrenic resin obtained by recycling cutting waste generated in the finish cutting process of the product can also be used. These styrenic resins may be fed as they are into the extruder, or may be reduced in volume and pelletized so as to be easily fed into the extruder.

  In the present invention, the flame retardant comprises (A): tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tetrabromobisphenol-A-bis (2,3-dibromopropyl ether). Mixed brominated flame retardant, or mixed brominated flame retardant consisting of (B): tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tris (2,3-dibromopropyl) isocyanurate By containing a flame retardant, flame retardance can be imparted to the resulting styrene resin foam.

The content of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether contained in the mixed brominated flame retardant (A) or (B) in the extruded styrene resin foam of the present invention is mixed When the whole brominated flame retardant is 100% by weight, it is preferably 25% by weight to 75% by weight.
Although the reason is not clear, when the tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether contained in the mixed brominated flame retardant is in the range of 25 to 75% by weight, the obtained extrusion Regarding the flame retardant performance of the foam, tetrabromobisphenol-A-bis (tetrabromobisphenol-A-bis, which is the mixing partner, is probably due to the high flame retardant performance of 2,3-dibromo-2-methylpropyl ether. The low flame retardant performance, which was a disadvantage of (2,3-dibromopropyl ether) or (2,3-dibromopropyl) isocyanurate, was canceled out as if tetrabromobisphenol-A-bis (2,3-dibromo-2-methyl High flame retardant performance as if it were propyl ether alone can be expressed. Regarding the thermal stability of the body, the content of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether, which has low thermal stability, can be reduced, and instead, tetrabromobisphenol with high thermal stability. Since it can contain -A-bis (2,3-dibromopropyl ether) or (2,3-dibromopropyl) isocyanurate, the thermal stability is tetrabromobisphenol-A-bis (2,3-dibromo It can be higher than using -2-methylpropyl ether alone.

When the content of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether is less than 25% by weight when the total mixed flame retardant is 100% by weight, the obtained flame retardancy tends to be low If it exceeds 75% by weight, the thermal stability tends to deteriorate.
In consideration of the dispersion and variation of the flame retardant in the styrene resin, when trying to stably obtain higher flame retardancy and higher thermal stability, tetrabromobisphenol-A-bis (2 The content of 3-dibromo-2-methylpropyl ether is preferably in the range of 35 to 65% by weight.

  The content of the mixed brominated flame retardant in the styrene resin extruded foam of the present invention can obtain the combustibility specified in JIS A9511, and the thermal stability of the styrene resin in the extruder during foam production. The amount of foaming agent added, the density of the foam, and depending on the case, the type or amount of other additives may be appropriately adjusted so that it can be maintained. 1 to 6 parts by weight is preferable.

  When the content of the mixed brominated flame retardant is less than 1 part by weight, good properties as a foam such as flame retardancy tend to be difficult to obtain. When the content exceeds 6 parts by weight, stability during foam production And surface properties may be impaired.

  In the styrene-based resin extruded foam of the present invention, by using a nitrogen-containing compound and a phosphate ester, it is possible to express higher flame retardancy.

  The nitrogen-containing compound used in the present invention is a compound selected from cyanuric acid, isocyanuric acid and derivatives thereof represented by the following general formula 1 and general formula 2. These compounds may be used alone or in combination of two or more.

[Wherein R ¹ , R ² and R ³ are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an organic group represented by —Y—X (wherein Y is an alkylene group having 1 to 6 carbon atoms, , A phenylene group or a cycloalkylene group, and X is a monovalent organic group containing an epoxy group, a carboxyl group, a hydroxyl group, an amino group, a phenyl group or a phosphorus atom), and a phenyl group, which are different from each other Is also good]

[Wherein R ⁴ , R ⁵ , R ⁶ are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an organic group represented by —Y—X (wherein Y is an alkylene group having 1 to 6 carbon atoms, , A phenylene group or a cycloalkylene group, and X is a monovalent organic group containing an epoxy group, a carboxyl group, a hydroxyl group, an amino group, a phenyl group or a phosphorus atom), and a phenyl group, which are different from each other Is also good]
In the general formula 1 or 2, examples of the alkyl group having 1 to 8 carbon atoms represented by R ¹ , R ² , R ^3, R ⁴ , R ⁵ , R ⁶ include, for example, methyl, ethyl, propyl, i-propyl Butyl, i-butyl, s-butyl, t-butyl, pentyl, hexyl, octyl and the like. Examples of the monovalent organic group containing a phosphorus atom represented by X include a phosphonate residue and a phosphate ester residue. Examples of the alkylene group having 1 to 6 carbon atoms represented by Y include methylene, ethylene, trimethylene, propylene, tetramethylene and hexamethylene. Examples of the cycloalkylene group represented by Y include cyclohexene.

  Specific examples of nitrogen-containing compounds used in the present invention include cyanuric acid, monoalkyl cyanurates such as methyl cyanurate, dialkyl cyanurates such as diethyl cyanurate, trialkyl cyanurates such as trimethyl cyanurate and triethyl cyanurate, Dialkyl phenyl cyanurates such as phenyl cyanurate, diphenyl cyanurate, triphenyl cyanurate, dimethylphenyl cyanurate, monoalkyl isocyanurates such as isocyanuric acid, methyl isocyanurate, dialkyl isocyanurates such as diethyl isocyanurate, trimethyl isocyanurate, Trialkyl isocyanurates such as triethyl isocyanurate, phenyl isocyanurate, diphenyl isocyanurate, triphenyl Di (aminoalkyl) isocyanurates such as dialkylphenyl isocyanurates such as sosocyanurates, dimethylphenyl isocyanurates, mono (aminoalkyl) isocyanurates such as mono (2-aminoethyl) isocyanurates, and di (2-aminoethyl) isocyanurates Tri (aminoalkyl) isocyanurate such as tri (2-aminoethyl) isocyanurate, tri (hydroxymethyl) isocyanurate, tri (2-hydroxyethyl) isocyanurate, tri (2-hydroxypropyl) isocyanurate (Hydroxyalkyl) isocyanurate, di (hydroxyalkyl) isocyanurate such as di (hydroxymethyl) isocyanurate, bis (2-carboxyethyl) isocyanurate, etc. 1,3,5-tris (carboxyalkyl) isocyanurate, tris (2,3-epoxypropyl) isocyanurate such as s (carboxyalkyl) isocyanurate, 1,3,5-tris (2-carboxyethyl) isocyanurate Etc.

  The nitrogen-containing compound is preferably a compound that is flame retardant and decomposes or melts at 270 ° C. to 400 ° C.

  Further, as the nitrogen-containing compound, a compound that does not inhibit the effect of generating both the small bubbles and the large bubbles in the foam when water is used as another foaming agent in order to obtain high heat insulation and the like. For example, a compound that is hardly soluble in water or has a solubility in water of 10% by weight or less in a temperature range around room temperature (around 10 to 30 ° C.) is preferable. When the solubility in water is high, the effect of generating both the small bubbles and the large bubbles tends to be hindered.

Particularly preferred among the nitrogen-containing compounds are cyanuric acid (in which R ¹ , R ² and R ³ in the general formula 1 are hydrogen atoms), isocyanuric acid (R in the general formula 2) from the viewpoint of easy availability. ⁴ , R ⁵ and R ⁶ are hydrogen atoms), bis (2-carboxyethyl) isocyanurate (R ⁴ in general formula 2 is a hydrogen atom, and in R ⁵ and R ⁶ , Y is an ethylene group, X Is a carboxyl group).

  The content of the nitrogen-containing compound in the present invention is appropriately adjusted according to the amount of foaming agent added so that the flame retardancy specified in JIS A9511 and the ignition or combustion suppression effect of hydrocarbons that volatilize during combustion can be obtained. However, it is 0.1 to 10 parts by weight, preferably 1 to 9 parts by weight, more preferably 1.5 to 8 parts by weight, particularly preferably 2 to 100 parts by weight of the styrene resin. 7 parts by weight. If the content of the nitrogen-containing compound is less than 0.1 parts by weight, the flame retardancy targeted by the present invention tends to be difficult to obtain. On the other hand, if it exceeds 10 parts by weight, the moldability during foam production, etc. May be damaged.

  Examples of the phosphate ester compound used in the present invention are trialkyl phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, and tri (2-ethylhexyl) phosphate (alkyl groups having 1 to 12 carbon atoms are preferable). ), Trialkoxyalkyl phosphates such as tributoxyethyl phosphate (alkoxyalkyl groups preferably have 2 to 12 carbon atoms), dialkyl phosphates (alkyl groups preferably have 1 to 12 carbon atoms), monoisodecyl Monoalkyl phosphates such as phosphate (alkyl groups having 1 to 12 carbon atoms are preferred), 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate Aliphatic phosphates such as phosphates, triphenyl phosphate, tricresyl phosphate, trixyl phosphate, tris (isopropylphenyl) phosphate, tris (phenylphenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphate, xylyl Triaryl phosphates such as diphenyl phosphate and di (isopropylphenyl) phenyl phosphate (the rule group may be substituted with an alkyl group, a phenyl group, etc.), diphenyl (2-ethylhexyl) phosphate, diphenyl (2-acryloyloxyethyl) Diaryl alkyl phosphates such as phosphate and diphenyl (2-methacryloyloxyethyl) phosphate (aryl group, alkyl group is substituted) And aromatic phosphoric acid esters such as good) and the like. Furthermore, the phosphate ester which has two or more phosphate ester groups is mention | raise | lifted. These compounds may be used alone or in combination of two or more.

  As the phosphoric ester compound, a compound having a melting point lower than 150 ° C. is preferable from the viewpoint of moldability.

  Among the phosphoric acid ester compounds, triphenyl phosphate is particularly preferable from the viewpoint of cost.

  The content of the phosphate ester compound is appropriately adjusted in accordance with the amount of foaming agent added so as to obtain the flame retardancy specified in JIS A9511 and the ignition or combustion suppression effect of hydrocarbons that volatilize during combustion. However, it is 0.1 to 10 parts by weight, preferably 0.3 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, and particularly preferably 0 to 100 parts by weight of the styrene resin. .8 to 2 parts by weight. If the content of the phosphoric ester compound is less than 0.1 parts by weight, the flame retardancy targeted by the present invention tends to be difficult to obtain. It may impair the sex.

  In the present invention, it is presumed that a synergistic effect of combustion inhibition is achieved by mixing the phosphoric ester compound in the above-mentioned appropriate amount range with respect to the mixed brominated flame retardant and the nitrogen-containing compound, High flame retardancy is easily obtained.

That is, when only a mixed brominated flame retardant and a nitrogen-containing compound are used in combination, there is a tendency that flame retardancy is not always stably obtained with a small amount of addition. Further, when the amount added is increased, the foam may be peeled off immediately after being extruded from the die, or it may be torn off, and there is a tendency that the foam cannot be obtained satisfactorily.
In particular, when saturated hydrocarbons are used as the foaming agent, when the foam is burned, the residual foaming agent is released from the foam into the atmosphere, and the foaming agent burns, so that the foaming is generated by the combustion heat of the foaming agent. There is a tendency for the body surface to melt and spread.
However, these tendencies can be greatly reduced by inhibiting the combustion of the residual foaming agent by using a phosphoric ester compound in combination with the mixed brominated flame retardant and the nitrogen-containing compound. An excellent effect that it can be obtained is obtained, and a foamed molded article having excellent flame retardancy and stability of molding processing is obtained.

  In addition, the amount of the phosphate ester compound is usually compared to 100 parts by weight of the styrene resin by combining it with a mixed bromine flame retardant and a nitrogen-containing compound as compared with the case where it is used alone as a flame retardant. Depending on the type of the resin, 10 to 30 parts by weight or more of what is required can achieve the effects of the present invention with an extremely small amount of about several parts by weight.

Although it does not specifically limit as a foaming agent used by this invention, The outstanding environmental compatibility can be provided by using a C3-C5 saturated hydrocarbon.
Examples of the saturated hydrocarbon having 3 to 5 carbon atoms used in the present invention include propane, n-butane, i-butane, n-pentane, i-pentane, neopentane and the like. Among these saturated hydrocarbons having 3 to 5 carbon atoms, propane, n-butane, i-butane, or a mixture thereof is preferable from the viewpoint of foamability. Moreover, n-butane, i-butane, or a mixture thereof is preferable from the viewpoint of the heat insulating performance of the foam, and i-butane is particularly preferable.

  In the present invention, by using another foaming agent, a plasticizing effect and an auxiliary foaming effect at the time of foam production can be obtained, the extrusion pressure can be reduced, and the foam can be stably produced. However, depending on various properties of the foam, such as the desired foaming ratio and flame retardancy, the amount used may be limited, and the extrusion foam moldability may not be sufficient.

  Other foaming agents include, for example, ethers such as dimethyl ether, diethyl ether, methyl ethyl ether, isopropyl ether, n-butyl ether, diisopropyl ether, furan, furfural, 2-methyl furan, tetrahydrofuran, tetrahydropyran; dimethyl ketone, methyl ethyl ketone , Diethyl ketone, methyl n-propyl ketone, methyl-n-butyl ketone, methyl-i-butyl ketone, methyl-n-amyl ketone, methyl-n-hexyl ketone, ethyl-n-propyl ketone, ethyl-n-butyl ketone, etc. A saturated alcohol having 1 to 4 carbon atoms such as methanol, ethanol, propyl alcohol, i-propyl alcohol, butyl alcohol, i-butyl alcohol, t-butyl alcohol; Organic esters such as acid methyl ester, formic acid ethyl ester, formic acid propyl ester, formic acid butyl ester, formic acid amyl ester, propionic acid methyl ester, propionic acid ethyl ester; alkyl halides such as methyl chloride and ethyl chloride A foaming agent, an inorganic foaming agent such as water or carbon dioxide, a chemical foaming agent such as an azo compound or tetrazole, or the like can be used. These other blowing agents may be used alone or in combination of two or more.

  Among other foaming agents, from the viewpoints of foamability, foam formability, etc., saturated alcohols having 1 to 4 carbon atoms, dimethyl ether, diethyl ether, methyl ethyl ether, methyl chloride, ethyl chloride, etc. are preferable. From the viewpoints of the flammability of the foam, the flame retardancy of the foam, the heat insulation properties described later, and the like, water and carbon dioxide are preferred. Among these, dimethyl ether is particularly preferable from the viewpoint of the plasticizing effect, and water is particularly preferable from the viewpoint of the effect of improving the heat insulation by controlling the cost and the bubble diameter.

  The pressure when adding or injecting the foaming agent is not particularly limited as long as it is higher than the internal pressure of an extruder or the like.

  The amount of the foaming agent used in the present invention is preferably 2 to 20 parts by weight and more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the styrene resin. When the amount of the foaming agent used is less than 2 parts by weight, the foaming ratio is low, and the characteristics such as light weight and heat insulation as the resin foam may be difficult to be exhibited. When the amount exceeds 20 parts by weight, the amount of the foaming agent is excessive. In some cases, defects such as voids may occur in the foam.

  In the present invention, when water or alcohol is used as the other foaming agent, it is preferable to add a water-absorbing substance in order to stably perform extrusion foaming.

  Specific examples of the water-absorbing substance used in the present invention include, for example, a polyacrylate polymer, a starch-acrylic acid graft copolymer, a polyvinyl alcohol polymer, a vinyl alcohol-acrylate copolymer, In addition to water-absorbing polymers such as ethylene-vinyl alcohol copolymers, acrylonitrile-methyl methacrylate-butadiene copolymers, polyethylene oxide copolymers, and derivatives thereof, anhydrous silica having silanol groups on the surface (oxidized) Silicon) [for example, AEROSIL manufactured by Nippon Aerosil Co., Ltd. is commercially available] and the like; fine powder having a particle size of 1000 nm or less having a hydroxyl group on the surface; water-absorbing or water-swelling properties such as smectite and swellable fluoromica Layered silicates and their organically treated products: zeolite, activated carbon, aluminum , Silica gel, porous glass, activated clay, porous material or the like, such as diatomaceous earth and the like.

  The addition amount of the water-absorbing substance used in the present invention is appropriately adjusted depending on the addition amount of water and the like, but is preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the styrene resin. 0.1 to 3 parts by weight is more preferable.

  In the present invention, processing aids such as fatty acid metal salts, fatty acid amides, fatty acid esters, liquid paraffin, and olefinic wax, flame retardants other than those described above, and antistatic properties, as long as they do not inhibit the effects of the present invention. Additives such as colorants such as agents and pigments can be included.

  Furthermore, in the present invention, if necessary, a stabilizer such as a phenolic antioxidant, a nitrogenous stabilizer, a sulfurous stabilizer, a lactone stabilizer, a benzotriazole or a hindered amine is further contained. Can do.

  Specific stabilizers include bis (2,2,6,6-tetramethyl-4-piperidinyl) decanedioate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) decanedioate. , Bis (2,2,6,6-tetramethyl-1 (octyloxy-4-piperidinyl) decanedioate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3 , 4-Butanetetracarboxylate and other hindered amine stabilizers, ethylenebis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate], pentaerythritol tetrakis [3- Phenolic stabilizers such as (3,5-di-t-butyl-4-hydroxyphenyl) propionate], etc. These may be used alone, Alternatively, bis (2,2,6,6-tetramethyl-4-piperidinyl) decanedioate, bis (1,2,2,6,6-pentamethyl-decanedioate) may be used. 4-piperidinyl), bis (2,2,6,6-tetramethyl-1) (octyloxy-4-piperidinyl), tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1 Hindered amine stabilizers such as 1,2,3,4-butanetetracarboxylate are preferably used because they do not reduce the flame retardancy of the foam and improve the thermal stability of the foam. .

  As a method for producing a styrene resin extruded foam of the present invention, a styrene resin, a mixed bromine flame retardant, a nitrogen-containing compound, a phosphate ester compound, other additives, etc. are supplied to a heating and melting means such as an extruder. In any stage, a foaming agent is added to the styrenic resin under high-pressure conditions to form a fluid gel, and after cooling to a temperature suitable for extrusion foaming, the fluid gel is extruded and foamed into a low-pressure region through a die. Manufactured by forming a foam.

  Styrenic resin, bromine-based flame retardant, nitrogen-containing compound, phosphate ester-based compound, and other additives, etc. are heated and melted as styrene-based resin, brominated flame retardant, nitrogen-containing compound, phosphate ester-based Compound and other additives are mixed and then heated and melted; after styrene resin is heated and melted, brominated flame retardant, nitrogen-containing compound, phosphate ester compound, and other additives are added and mixed; After mixing styrene resin with brominated flame retardant, nitrogen-containing compound, phosphate ester compound, stabilizer, and other additives, prepare a heated and melted composition, supply it to the extruder again, and heat and melt it And so on.

There are no particular restrictions on the heating temperature, melt kneading time, and melt kneading means when heating and kneading the styrene resin and additives such as a foaming agent.
Although heating temperature should just be more than the temperature which the styrene resin to use melt | dissolves, the temperature which suppresses the molecular degradation of resin as much as possible including the influence of a flame retardant etc., for example, about 150-250 degreeC is preferable.
The melt-kneading time varies depending on the amount of extrusion per unit time, the melt-kneading means, etc., and thus cannot be determined unconditionally. However, the time required for uniformly dispersing and mixing the styrene resin and the foaming agent is appropriately selected.
Examples of the melt-kneading means include a screw type extruder, but there is no particular limitation as long as it is used for ordinary extrusion foaming. However, in order to suppress the molecular degradation of the resin as much as possible, it is preferable to use a low shear type screw for the screw shape.

  The foam molding method is not particularly limited, for example, using a molding die and a molding roll in which a foam obtained by releasing pressure from a slit die is placed in close contact with or in contact with the slit die, a plate shape having a large cross-sectional area A general method for forming a foam can be used.

  The thickness of the styrene resin extruded foam of the present invention is not particularly limited and is appropriately selected depending on the application. For example, in the case of a heat insulating material used for applications such as building materials, in order to give preferable heat insulating properties, bending strength and compressive strength, those having a thickness like a normal plate-like material are preferable, usually 10 to 10 150 mm, preferably 20-100 mm.

The density of the styrene resin extruded foam of the present invention is preferably 15 to 50 kg / m ³ in order to give light weight and excellent heat insulation, bending strength and compressive strength, and preferably 25 to 40 kg / m ^3. m and even more preferably ^3.

  The styrene resin extruded foam of the present invention is suitably used as a heat insulating material for building materials from the viewpoint of excellent flame retardancy, heat insulating properties and thermal stability.

Next, although the manufacturing method of the thermoplastic resin extrusion foam of this invention is demonstrated still in detail based on an Example, this invention is not restrict | limited only to this Example.
Unless otherwise specified, “parts” represents parts by weight and “%” represents% by weight.

The raw materials used in the examples and comparative examples are as follows.
(1) Styrenic resin [PS940, G9401]
(2) Mixed brominated flame retardant Flame retardant (A)
Tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether [Daiichi Kogyo Seiyaku Co., Ltd., Pyroguard SR-130]
Tetrabromobisphenol A-bis (2,3-dibromopropyl) ether [Daiichi Kogyo Seiyaku Co., Ltd., Pyroguard SR-720]
Flame retardant (B)
Tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether [Daiichi Kogyo Seiyaku Co., Ltd., Pyroguard SR-130]
Tris (2,3-dibromopropyl) isocyanurate [Nippon Kasei Co., Ltd., TAIC-6B]
(3) Nitrogen-containing compound / isocyanuric acid [manufactured by Shikoku Kasei Co., Ltd., trade name: ICA-P]
・ Bis (2-carboxyethyl) isocyanurate [manufactured by Shikoku Kasei Co., Ltd.]
(4) Phosphate ester compound, triphenyl phosphate [Daihachi Chemical Industry Co., Ltd., trade name: TPP]
Resorcinol dicresyl phosphate “Asahi Denka Kogyo Co., Ltd., trade name: ADK STAB FP-500”]
(5) Foaming agent, isobutane [Mitsui Chemicals, Inc.]
・ Normal butane [manufactured by Iwatani Corporation]
・ Dimethyl ether [Mitsui Chemicals, Inc.]
・ Water [tap water]
(6) Other additives
・ Talc [manufactured by Hayashi Kasei Co., Ltd., Talcan powder PK-Z]
Bentonite [Wilver Ellis, Gel White H]
・ Aerosil [Nippon Aerosil Co., Ltd., AEROSIL]

  The evaluation methods implemented in the examples and comparative examples are as follows.

(1) Foam density Foam density is determined based on foam density (g / cm ³ ) = foam weight (g) / foam volume (cm ³ ), and the unit is converted to (kg / m ³ ). Showed.

(2) Average cell diameter (mm)
The cell diameter in each direction was measured according to ASTM D-3576.
The cross-section in the width direction of the foam is enlarged and projected 50 to 100 times, and the cell diameter (HD) in the thickness direction and the cell diameter (TD) in the width direction are measured. Next, the cross section in the extrusion direction was enlarged and projected, and the cell diameter (MD) in the extrusion direction was measured.
The average cell diameter was calculated from the following formula by taking the cube of the product of the cell diameters in each direction.
Average cell diameter = (HD x TD x MD) ^1/3

(3) Flammability
In accordance with JIS A9511, a test piece having a thickness of 10 mm, a length of 200 mm, and a width of 25 mm was used, and evaluation was performed according to the following criteria. The measurement was performed on the foam after 7 days after being cut into the above-mentioned dimensions after production.
Burning time
A: All five flame extinguishing times are within 3 seconds.
○: At least one of the five flame extinguishing times exceeds 3 seconds, but the remaining three or more are within 3 seconds.
Δ: At least 3 out of 5 flame extinguishing times exceed 3 seconds, but the remaining one or more are within 3 seconds.
X: All 5 flame extinguishing times exceed 3 seconds.
Burning distance
A: All five stops within the limit line.
○: At least one of the five lines decreases over the limit line, but the remaining three or more lines stop burning within the limit line.
Δ: Combustion exceeds the limit line for at least three of the five, but combustion stops within the limit line for the remaining one or more.
X: Combustion exceeds the limit line with all five.
Combustion status
(Double-circle): Combustion of a foaming agent is not seen at all.
○: Some burning of the foaming agent is observed.
Δ: Combustion of the foaming agent is observed, but no complete burning occurs.
X: Combustion of the foaming agent is also observed, and it is completely burned.

(4) Oxygen index About the foam which passed 7 days after manufacture, according to JISK7201, it measured using the test piece of thickness 10mm * length 150mm * width 10mm.
○: 29% or more.
Δ: 26% or more and less than 29%.
X: Less than 26%.

(5) Thermal conductivity It measured according to JIS A9511 about the foam which passed 7 days after manufacture.
○: Less than 0.0260 W / mK.
Δ: 0.0260 W / mK or more and less than 0.0285 W / mK.
X: 0.0285 W / mK or more.

(6) Specific Viscosity Reduction Rate of Foam In order to evaluate the degree of resin deterioration associated with the heat history in the extruder, the specific viscosity reduction rate of the foam was determined by the following procedure.
a) About 1 g of extruded foam is dissolved in about 30 mL of methyl ethyl ketone in a test tube with a stopper, and the test tube is stoppered and allowed to stand for 6 hours or more. After standing, the supernatant in the test tube is taken out into a beaker, ethanol is added to reprecipitate the resin, and the solvent is completely evaporated in an oven at 70 ° C.
b) 250 mg of the obtained resin content is dissolved in 25 mL of toluene, and the specific viscosity with respect to toluene at 30 ° C. is measured with respect to 10 mL of the obtained toluene solution using an Ubbelohde viscosity tube. The specific viscosity is calculated by the following formula.
Specific viscosity (ηsp) = (sample transit time) / (chloroform transit time) −1
c) The rate of decrease in the specific viscosity (ηsp (foam)) of the foam relative to the resin specific viscosity (ηsp (resin)) used is calculated by the following equation.
Specific viscosity reduction rate of foam = specific viscosity of foam (ηsp (foam)) / specific viscosity of resin used (ηsp (resin))
The obtained values were judged according to the following criteria.
○: The specific viscosity reduction rate of the foam is 0.85 or more.
(Triangle | delta): The specific viscosity fall rate of a foam is 0.75 or more and less than 0.85.
X: The specific viscosity reduction rate of a foam is less than 0.75.

(7) Processing stability during foam production
The foam extruded from the slit die was molded with a molding die, and the foam state when obtaining a plate-like foam was judged according to the following criteria.
○: The foam surface is smooth and gloss is recognized.
Δ: The foam surface is smooth, but fine wrinkles and flow patterns are observed on the surface.
X: Cracks, tears, cracks, tears, and tears are observed on the foam surface.

Example 1
For 100 parts of polystyrene resin (G9401), 1.5 parts by weight of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether and tetrabromobisphenol A-bis ( 2,3-dibromopropyl ether) 2.5 parts by weight (4 parts in total), isocyanuric acid 2 parts by weight as a nitrogen-containing compound, triphenyl phosphate 2 parts by weight as a phosphate ester compound, talc 0.8 parts by weight A resin mixture consisting of 1.0 part by weight of bentonite and 0.1 part by weight of Aerosil was dry blended.
About 50 kg / hr of the obtained resin mixture to a tandem type two-stage extruder in which a single screw extruder (first extruder) having a diameter of 65 mm and a single screw extruder (first extruder) having a diameter of 90 mm are connected in series. Was supplied at a rate of
The resin mixture supplied to the first extruder was melted or plasticized and kneaded by heating to a resin temperature of 200 ° C., and the foaming agent shown below was press-fitted into the resin near the tip of the first extruder. Thereafter, in the second extruder connected to the first extruder, the resin temperature is cooled to 120 ° C., and the atmosphere of the rectangular cross-section die having a thickness of 2 mm × width of 50 mm provided at the tip of the second extruder. After extrusion foaming, an extruded foam plate having a cross-sectional shape of 50 mm in thickness and 150 mm in width was obtained with a molding die placed in close contact with the die and a molding roll installed on the downstream side thereof.
In addition, as a foaming agent, 4.5 weight part of isobutane, 2.5 weight part of dimethyl ether, and 0.5 weight part of water were used with respect to 100 weight part of styrene resin.
The properties of the obtained foam are shown in Table 1.
It turns out that the outstanding performance is expressed compared with Comparative Examples 1-5.

(Examples 2-5, Reference Examples 1-3, Comparative Examples 1-5)
As shown in Table 1, types and amounts and types of mixed brominated flame retardants, types and amounts of nitrogen-containing compounds, types and amounts of phosphate ester compounds, types and amounts of foaming agents, and types of other additives A foam was obtained in the same manner as in Example 1 except that the amount was changed.

As is clear by comparing Examples 1 to 5 and Comparative Examples 1 to 5, with respect to 100 parts by weight of the styrene resin, the type and amount and type of the mixed brominated flame retardant, the type and amount of the nitrogen-containing compound, It can be seen that by specifying the type and amount of the phosphoric ester compound, an extruded foam having improved flame retardancy, heat insulation, thermal stability and processing stability can be obtained stably.

Claims (9)

A styrene resin foam obtained by heating and melting a styrene resin, adding a foaming agent containing at least one selected from saturated hydrocarbons having 3 to 5 carbon atoms, and extruding and foaming the same. 1 to 6 parts by weight of mixed brominated flame retardant with respect to 100 parts by weight of the resin based on
Further, 0.1 to 10 parts by weight of a nitrogen-containing compound and 0.1 to 10 parts by weight of a phosphate ester compound are contained,
The mixed brominated flame retardant is
(A) a mixed brominated flame retardant comprising tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tetrabromobisphenol-A-bis (2,3-dibromopropyl ether), or
(B) a mixed brominated flame retardant composed of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tris (2,3-dibromopropyl) isocyanurate;
And when the content of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) in the mixed brominated flame retardant is 100% by weight based on the total mixed brominated flame retardant, A styrene-based resin extruded foam, characterized by being 25% to 75% by weight.   The content of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) in the mixed brominated flame retardant is 35% when the total mixed brominated flame retardant is 100% by weight. The styrene resin extruded foam according to claim 1, wherein the styrenic resin extruded foam is characterized by being in a range of from% to 65% by weight.   The styrene resin extruded foam according to claim 1 or 2, wherein the nitrogen-containing compound of the flame retardant (B) is isocyanuric acid and / or bis (2-carboxyethyl) isocyanurate.   The styrene resin extruded foam according to any one of claims 1 to 3, wherein the phosphate ester compound is trimethyl phosphate.   The styrenic resin foam according to any one of claims 1 to 4, wherein the foaming agent contains at least one selected from saturated hydrocarbons having 3 to 5 carbon atoms.   The foaming agent further comprises at least one selected from the group consisting of water, carbon dioxide, nitrogen, alcohols having 2 to 5 carbon atoms, dimethyl ether, methyl chloride, and ethyl chloride. The styrene resin foam according to any one of 5.   In the combustion measurement specified in JIS A9511, flame extinguishes within 3 seconds, there is no residue, it does not burn beyond the combustion limit indicator line, and it has flame retardant performance that satisfies the condition that the oxygen index is 26% or more The present invention relates to a styrenic resin foam according to any one of claims 1 to 6.   The styrenic resin foam according to any one of claims 1 to 7, which has a heat insulation performance of 0.028 W / mK or less in the thermal conductivity measurement specified in JIS A9511. A method for producing a styrene resin foam by heating and melting a styrene resin, adding a foaming agent, and extruding and foaming this,
Containing 1 to 6 parts by weight of mixed brominated flame retardant with respect to 100 parts by weight of styrene resin,
Furthermore, 0.1 to 10 parts by weight of a nitrogen-containing compound, 0.1 to 10 parts by weight of a phosphate ester compound,
The mixed brominated flame retardant is
(A) a mixed brominated flame retardant comprising tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tetrabromobisphenol-A-bis (2,3-dibromopropyl ether), or
(B) a mixed brominated flame retardant composed of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) and tris (2,3-dibromopropyl) isocyanurate;
And when the content of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) in the mixed brominated flame retardant is 100% by weight based on the total mixed brominated flame retardant, A method for producing an extruded foam of a styrenic resin, characterized by being 25% by weight to 75% by weight.