JPH11255946A - Foamable styrene-based resin particle having flame retardance and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a foamed molding having excellent flame retardance and a low heat shrinkage factor without impairing foaming property in foamable styrene-based resin particles and foamable resin particles capable of providing such foamed molding. SOLUTION: In the foamable styrene-based resin particles containing a foaming agent in styrene-based resin particle body, tetrabromobisphenol A diallyl ether having <=120 μm average particle diameter is impregnated in a range of 1.0-5.0 wt.% based on total amount of styrene-based resin particle body and tetrabromobisphenol A diallyl ether.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to expandable styrene resin particles having flame retardancy and a method for producing the same.
More specifically, by impregnating the foamable styrene resin particles with a specific flame retardant in a specific amount, the foam moldability of the foamable styrene resin particles and the dimensional stability of the foam molded article obtained therefrom are maintained. The present invention relates to expandable styrene-based resin particles which provide excellent flame retardancy and have an excellent balance of properties and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, foamed styrene resin products have been widely used as heat insulating materials and container materials because of their excellent lightness and heat insulating properties. However, foamed molded articles made of a styrene-based resin have a drawback that they contain a large amount of air due to their structure and are easily flammable. Therefore, its use has been limited to applications requiring flame retardancy, such as building materials.

[0003] Therefore, as a method of flame retarding a foamed molded article made of a styrene resin, a method of adding a flame retardant during polymerization of a styrene monomer has been studied. However, when a flame retardant is added at the time of polymerization, there have been problems in that the polymerization rate of the monomer is reduced and the yield is reduced, or the polymerization reaction is likely to be non-uniform. In addition, the addition of the flame retardant also causes problems such as a decrease in the foaming property of the expandable styrene resin particles, or a deterioration in heat resistance (stability at high temperatures) and weather resistance of the obtained foamed molded article. Was seen.

[0004] Further, a method of coating a flame retardant on the surface of the expandable resin particles after polymerization of the expandable resin particles has been studied. However, this method has a problem that the flame retardant is easily desorbed, and the flame retardant effect is likely to change (decrease) with time. In addition, since the flame retardant is easily detached, the inside of the foaming molding machine for foaming the foamable resin particles is contaminated, and there is a problem that a separate cleaning time is required.

Therefore, the inventors have found that the particle size of the flame retardant has a great effect on imparting flame retardancy, and that the use of a specific amount of such a flame retardant results in the expansion of the expandable resin particles. Without impairing the foamability of the foam, and found that a foam molded article having excellent flame retardancy and high-temperature dimensional stability can be obtained,
The present invention has been completed.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a foamed molded article or foam which exhibits excellent flame retardancy without deteriorating the foamability of the foamable resin particles and exhibits a low heat shrinkage at high temperatures. An object of the present invention is to provide expandable styrene-based resin particles from which such a foamed molded article can be obtained.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an expandable styrene resin particle having a styrene resin particle body containing a foaming agent, wherein tetrabromobisphenol A diallyl ether having an average particle diameter of 120 μm or less is used. The present invention relates to flame-retardant expandable styrene-based resin particles which are impregnated within a range of 1 to 5% by weight based on the total amount of the resin particle main body and tetrabromobisphenol A diallyl ether. By impregnating the expandable polystyrene resin particles with the above-mentioned 1 to 5% by weight of tetrabromobisphenol A diallyl ether having a specific particle diameter in this manner, the expandable polystyrene resin particles are imparted with excellent flame retardancy. Desorption of the burning agent can be reduced.
With this configuration, the expandability of the expandable polystyrene resin particles is not impaired, and further, in a foam molded product obtained from the expandable polystyrene resin particles,
There is no decrease in heat resistance.

Further, in constituting the flame-retardant expandable styrenic resin particles of the present invention, tricyclo [5, acrylate], based on the total weight of the styrenic monomer when polymerizing the styrenic resin particle body, is used. 2, 1, 0 ^2.6 ]
Deca-8-yl and tricyclomethacrylate [5,
2,1,0 ^2.6 ] dec-8-yl or any of 5 to 5
It is preferable to set the value in the range of 45% by weight.

Further, in constituting the flame-retardant expandable styrene resin particles of the present invention, the styrene monomer is used in an amount of 50 to 80 with respect to the total weight of the styrene monomer when the styrene resin particles are polymerized. It is preferable to set the value in the range of% by weight.

Further, when composing the flame-retardant expandable styrene resin particles of the present invention, α-methylstyrene is added to the total weight of the styrene monomer at the time of polymerization of the styrene resin particle body. It is preferable to set the value within a range of 45% by weight.

Further, in forming the flame-retardant expandable styrenic resin particles of the present invention, the foaming agent is a volatile volatile foaming agent, and the content of the volatile volatile foaming agent is adjusted to the styrene-based resin particles. It is preferable to set the value within a range of 3 to 10% by weight based on the total amount of the main body and the volatile volatile agent.

Another embodiment of the present invention relates to a method for producing flame-retardant expandable styrene resin particles, comprising the following steps (A) to (C). (A) A step of polymerizing a styrene-based monomer to produce a styrene-based resin particle main body. (B) The average particle diameter of the styrene resin particles is 120
μm or less of tetrabromobisphenol A diallyl ether, based on the total amount of the styrene-based resin particles and tetrabromobisphenol A diallyl ether, 1 to
Impregnating within 5% by weight. (C) a step of impregnating the styrenic resin particle body with a foaming agent.

[0013] Further, the method for producing foamable styrenic resin particles having flame retardancy of the present invention may further comprise (D) a step of coating the surface of the styrenic resin particle body with a coating agent. preferable.

In carrying out the method for producing flame-retardant expandable styrene resin particles of the present invention, it is preferable to impregnate tetrabromobisphenol A diallyl ether together with a dispersant.

In carrying out the method for producing expandable styrenic resin particles having flame retardancy of the present invention, step (B) and / or step (C) are carried out at 70-125.
The temperature is preferably in the range of ° C.

In carrying out the method for producing expandable styrene resin particles having flame retardancy of the present invention, it is preferable to carry out the steps (B) and (C) simultaneously.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the expandable styrene resin particles of the present invention and a method for producing the same will be specifically described.

1. Expandable styrene resin particles (1) Main body of styrene resin particles Expandable styrene resin particles can be prepared by impregnating a main body of styrene resin particles with a certain amount of a foaming agent.

Here, the kind of the resin constituting the main body of the styrene-based resin particles to be used is not particularly limited, and for example, a styrene homopolymer can be used. Further, a monomer component copolymerizable with a styrene monomer, for example, acrylonitrile, methacrylates such as methyl methacrylate, butyl methacrylate, acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, α-methyl Resins copolymerized with styrene monomers by using monomers of styrene derivatives such as styrene, chlorostyrene and vinyltoluene alone or in combination of two or more can be used. The styrene monomer and a monomer component copolymerizable with the styrene monomer are referred to as a styrene monomer.

However, even when these monomers are used in combination with the styrene monomer, the total weight of the styrene monomer when polymerizing the styrene resin particle body may be reduced.
It is preferred that the weight of the styrene monomer be a value within the range of 50 to 80% by weight. By setting the value in such a range, a uniform styrene-based resin particle body having more excellent heat resistance can be obtained.

Further, as described above, relative to the total weight of the monomers during the polymerization of styrene resin particle body, Akukuriru acid tricyclo [5,2,1,0 ^2.6] dec-8
Yl and tricyclomethacrylate [5,2,1,0
^2.6 ] 5 to 45% by weight of deca-8-yl or any of them
It is preferable to set the value within the range. These monomers are excellent in compatibility with the styrene-based monomer, and by setting the value in such a range, a styrene-based resin particle body having more excellent heat resistance can be obtained.

As described above, α-methylstyrene is preferably set to a value within a range from 5 to 45% by weight based on the total weight of the styrene monomer when polymerizing the styrene resin particles. α-Methylstyrene is excellent in compatibility with the styrene monomer, and by setting the value in such a range, a styrene-based resin particle body having more excellent heat resistance can be obtained.

The particle size of the styrene-based resin particle body is not particularly limited. For example, a styrene-based resin particle body having an average particle diameter in a range of 0.8 to 2.5 mm is used. It is preferred to use. If the styrene-based resin particles are in such a range, they can be appropriately foamed to form a dense molded product. Further, if the styrene-based resin particles are in such a range, they can be stably manufactured. Therefore, from the viewpoint of better balance between production stability and foamability,
It is more preferable to use a styrene-based resin particle body having an average particle diameter in a range of 0.8 to 2.0 mm.

(2) Blowing Agent In order to form the expandable styrene resin particles, it is necessary to use a blowing agent, but the type of the blowing agent used is not particularly limited. However, since it is generally easily available, and is in a liquid or gaseous state at room temperature, it may be an aliphatic hydrocarbon such as propane, isobutane, normal butane, isopentane, normal pentane, or hexane, or Freon 1
1, Freon-based compounds such as Freon 12 and the like can be used alone or in combination of two or more. It is also preferable to use an aliphatic hydrocarbon having 6 or more carbon atoms, an alicyclic hydrocarbon such as cyclohexane, or an aromatic hydrocarbon as the foaming aid in combination with the foaming agent.

Further, the amount of the foaming agent added (blending ratio) is 3 to the total amount of the foaming agent and the styrene resin particles.
It is preferable to set the value in the range of 10 to 10% by weight. When the amount of the foaming agent is less than 3% by weight, the foaming property tends to be remarkably reduced. On the other hand, when the amount exceeds 10% by weight, the impregnation time of the foaming agent tends to be extremely long.

(3) Softener It is preferable to use a softener to form the expandable styrene resin particles. By impregnating the expandable styrene resin particles with the softener, the expandability can be significantly improved. Further, by using such a softening agent, the impregnation property of the flame retardant is also improved.

Here, the kind of the softening agent used in the present invention is not particularly limited, but it is preferable to use a softening agent having a boiling point of 150 ° C. or less. Specifically, aromatic hydrocarbons such as ethylbenzene, toluene, styrene, benzene and xylene, halogenated hydrocarbons such as 1,2-dichloropropane and trichloroethylene, dioctyl adipate, dioctyl phthalate, dibutyl sebacate, butyl stearate, It is preferable to use epoxidized soybean oil, vegetable oil or the like alone or in combination of two or more.

(4) Coating agent It is preferable to coat a coating agent on the surface of the expandable styrene resin particles impregnated with a blowing agent and a phthalic acid ester. By using the coating agent in this way, dense,
A foam having excellent strength can be formed. In addition, when the impregnation of the flame-retardant into the expandable styrene resin particles is insufficient and a part of the expandable styrene resin particles adheres to the surface of the expandable styrene resin particles, the coating agent is used as described above. By covering the surface of the expandable styrenic resin particles by the above, the possibility that the flame retardant is desorbed is reduced as much as possible.

As the preferable coating agent, those usually used for expandable polystyrene resin particles can be used as they are. As a component constituting the coating agent, for example, zinc stearate, triglyceride stearate, monoglyceride stearate, hardened castor oil, amide compound, antistatic agent and the like can be used alone or in combination of two or more. .

(5) Flame Retardant In the present invention, tetrabromobisphenol A diallyl ether (including a tetrabromobisphenol A diallyl ether derivative) having an average particle diameter of 120 μm or less is used as a flame retardant. This is because tetrabromobisphenol A diallyl ether can impart excellent flame retardancy when used in a small amount, and is excellent in impregnating properties for expandable polystyrene resin particles. Further, tetrabromobisphenol A diallyl ether is a solid at room temperature, and can be easily selected from those having an appropriate average particle diameter. In addition, there is an advantage that it is easy to handle because it is not liquid or gaseous.

Here, the reason why tetrabromobisphenol A diallyl ether having an average particle diameter of 120 μm or less is used is that if the average particle diameter exceeds 120 μm, the impregnation property is reduced. That is, when the average particle diameter of the tetrabromobisphenol A diallyl ether becomes large, it is not easily impregnated into the expandable polystyrene resin particles, and remains attached to the surface or is easily detached from the expandable polystyrene resin particles. is there.

However, if the average particle size of the tetrabromobisphenol A diallyl ether is too small, the flame retardancy of the expandable polystyrene resin particles may be reduced,
Or it tends to be difficult to obtain. Therefore, the average particle size of the tetrabromobisphenol A diallyl ether is more preferably set to a value in the range of 0.1 to 100 μm, and the average particle size is set to a value in the range of 1.0 to 90 μm. More preferred.

In addition to the tetrabromobisphenol A diallyl ether, a conventionally used organic flame retardant having a relatively low molecular weight and a low melting point, such as tetrabromoethane, hexabromocyclododecane and tetrabromobisphenol A, may be used in combination. preferable. In this case, the amount of the organic flame retardant used in combination is preferably set to a value within the range of 1 to 20% by weight based on the total amount of the flame retardant.
If the amount is less than 1% by weight, a remarkable addition effect tends not to be obtained, while if it exceeds 20% by weight, the flame retardancy of the expandable polystyrene resin particles tends to decrease.

(6) Method for Producing Flame-Retardant Expandable Styrenic Resin Particles In producing the flame-retardant expandable styrene resin particles of the present invention, the following steps (A) to (D) are carried out. It is preferred to include. By producing in this manner, foamable styrene resin particles having excellent foamability and excellent flame retardancy and heat resistance can be efficiently produced.

(A) A step of polymerizing a styrene-based monomer to produce a styrene-based resin particle main body (hereinafter sometimes referred to as a step (A)). (B) The average particle diameter of the styrene resin particles is 120
1 μm or less of tetrabromobisphenol A diallyl ether (hereinafter sometimes referred to as a flame retardant) in an amount of 1 to 5% by weight based on the total amount of the styrene resin particles and tetrabromobisphenol A diallyl ether. (Hereinafter, may be referred to as a step (B)). (C) A step of impregnating the styrene-based resin particle main body with a foaming agent (hereinafter sometimes referred to as a step (C)). (D) a step of coating the surface of the main body of the styrene-based resin particles with a coating agent (hereinafter sometimes referred to as a step (D)).

First, the step (A) of preparing a styrene-based resin particle body by polymerizing a styrene-based monomer will be described. The polymerization method in this step (A) is not particularly limited, but for example, a suspension polymerization method is preferably employed. Specifically, in an aqueous medium containing a dispersant,
A suspension is prepared by dispersing a styrene-based monomer in which an organic peroxide is dissolved, and then heated to generate radicals to perform suspension polymerization, thereby easily and inexpensively obtaining the main body of the styrene-based resin particles. it can. The molecular weight of the styrene-based resin particles obtained by polymerization was determined to be 5,000 to 1,000,00 in terms of weight average molecular weight (Mw).
It is preferably set to a value in the range of 0, and 10,000 to 50
A value within the range of 000 is more preferable. The weight average molecular weight (Mw) is a value in terms of polystyrene, and is determined by gel permeation chromatography (GP).
C) can be measured.

In the suspension polymerization in the step (A), it is preferable to use a dispersant. By using the dispersant, the styrene-based resin particle main body can be more uniformly polymerized. Preferable dispersants include those containing a hardly soluble inorganic salt having a submicron particle system as a main component and a small amount of an anionic surfactant as a dispersing aid. Specifically, preferred poorly soluble inorganic salts include phosphates such as tricalcium phosphate and trimagnesium phosphate, carbonates such as calcium carbonate and magnesium carbonate, polyvinyl alcohol, alkyl cellulose, hydroxyalkyl cellulose, and carboxyalkyl. cellulose,
The use of sodium polyacrylate, polyvinylpyrrolidrin, or the like alone or in combination of two or more kinds may be mentioned.

The amount of the hardly soluble inorganic salt to be added is not particularly limited.
The value is preferably in the range of 0.1 to 10% by weight. If the amount of the hardly soluble inorganic salt is less than 0.1% by weight, it tends to be difficult to obtain a target low molecular weight product stably, while if it exceeds 10% by weight, the polymerization reaction is controlled. This is because it tends to be difficult to perform, or the characteristics of the expandable styrene resin particles obtained tend to decrease.

The hardly soluble inorganic salt is preferably added in two or more portions at the beginning of suspension polymerization and during the polymerization. In this case, the dispersion stability of the suspension can be significantly improved. Therefore, by adding in a plurality of times, the generation of rice cake-like substances can be effectively prevented, the heat generation can be easily controlled, and the workability of the dehydration and drying operation can be improved.

On the other hand, as the anionic surfactant used as a dispersant aid, sodium alkylsulfonate, sodium alkylbenzenesulfonate, sodium naphthalenesulfonate or the like may be used alone or in combination of two or more. it can. Also, the amount of the anionic surfactant used is not particularly limited, but the amount is preferably 0.001 to styrene monomer.
It is preferable to set the value within the range of 0.005% by weight.

As the organic peroxide used in the suspension polymerization, those having a 10-hour half-decomposition temperature in the range of 50 to 100 ° C. are preferable. Specifically, for example, lauroyl peroxide, benzoyl peroxide, t
tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate or the like alone,
Alternatively, two or more kinds can be used in combination.

The amount of the polymerization initiator to be used is not particularly limited, but the amount of the polymerization initiator to be used is in the range of 1 to 10% by weight based on the styrene monomer. Is preferred. If the amount of the polymerization initiator is less than 1% by weight, it tends to be difficult to stably obtain a styrene-based resin particle having a desired molecular weight,
On the other hand, if it exceeds 10% by weight, it tends to be difficult to control the polymerization reaction.

It is also preferable to use a chain transfer agent to adjust the molecular weight of the styrene resin particles. As such a chain transfer agent, a terpenoid compound such as octyl mercaptan, dodecyl mercaptan, α-methylstyrene dimer, terbinolene, myrcene, limonene, α-pinene, β-pinene may be used alone or in combination of two or more. it can.

The amount of the chain transfer agent is not particularly limited, but is preferably in the range of 0.1 to 10% by weight based on the styrene monomer. If the amount of the chain transfer agent is less than 0.1% by weight,
There is a tendency that it is difficult to obtain a target molecular weight product stably, while if it exceeds 10% by weight, it tends to be difficult to control a chain reaction.

Next, the step (B) of impregnating the styrene resin particle body with the flame retardant will be described. The method of impregnating the tetrabromobisphenol A diallyl ether is not particularly limited, and for example, the foaming agent can be impregnated under high temperature and pressure conditions using an autoclave or the like.

Specifically, the temperature in step (B) (impregnation temperature)
Is preferably in the range of 70 to 125 ° C.
If the impregnation temperature is lower than 70 ° C., the time required for impregnation with the flame retardant becomes longer, and the productivity tends to decrease. On the other hand, when the impregnation temperature exceeds 125 ° C., the main body of the styrene-based resin particles is softened, and the generation of irregularly shaped beads tends to increase. Therefore, from the viewpoint of better balance between the impregnating property of the flame retardant and the uniformity of the obtained particles, it is more preferable to set the impregnating temperature in the step (B) to a value in the range of 80 to 120 ° C. More preferably, the value is in the range of 85 to 115 ° C.

The impregnation time of the flame retardant is not particularly limited, but is preferably set to a value within a range of 10 minutes to 10 hours. If the impregnation time is shorter than 10 minutes, the impregnation of the flame retardant tends to be insufficient,
If the impregnation time exceeds 10 hours, the productivity tends to decrease. Therefore, from the viewpoint of better balance between the impregnation property of the flame retardant and the productivity, the impregnation time in the step (B) is more preferably set to a value within a range of 20 minutes to 8 hours, and 30 minutes. More preferably, it is set to a value within the range of 6 hours.

In carrying out the step (B), it is preferable to impregnate the styrene resin particles with tetrabromobisphenol A diallyl ether together with a dispersant. In this case, the flame retardant is more easily impregnated in the styrene resin particle body, and excellent flame retardancy can be obtained with a smaller amount of addition.

Here, as the dispersant to be used in combination with the tetrabromobisphenol A diallyl ether, it is preferable to use the same dispersant added when the styrene resin particles themselves are subjected to suspension polymerization. That is, there can be mentioned those containing a hardly soluble inorganic salt having a submicron particle system as a main component and a trace amount of an anionic surfactant as a dispersion aid. Preferred poorly soluble inorganic salts include phosphates such as tricalcium phosphate and trimagnesium phosphate, and calcium carbonate and carbonates such as magnesium carbonate alone.
Alternatively, two or more kinds can be used in combination.
Further, as preferred anionic surfactants, sodium alkyl sulfonate, sodium alkylbenzene sulfonate, sodium naphthalene sulfonate alone, etc.
Alternatively, two or more kinds can be used in combination.

In carrying out the step (B), tetrabromobisphenol A diallyl ether is classified using a sieve or the like, and the average particle diameter is preferably 0.1%.
値 120 μm, more preferably 1.0 to
It is preferable to prepare a value within the range of 100 μm. By doing so, the flame retardant is easily impregnated into the styrene resin particle main body, and more excellent flame retardancy can be obtained.

Next, the step (C) of impregnating a foaming agent will be described. The method for impregnating the main body of the styrene-based resin particles with the foaming agent is not particularly limited, and an impregnation method that has been conventionally generally used using an autoclave or the like can be employed as it is. Specifically, the temperature (impregnation temperature) in step (C) is preferably set to a value within the range of 70 to 125 ° C. When the impregnation temperature is lower than 70 ° C., the time required for impregnation with a foaming agent or a flame retardant increases, and the productivity tends to decrease. When the impregnation temperature exceeds 125 ° C., the styrene resin particles There is a tendency that the main body softens and the generation of odd-shaped beads increases. Therefore, from the viewpoint that the balance between the impregnating property of the foaming agent and the uniformity of the obtained particles is better, the impregnating temperature in the step (C) is more preferably set to a value in the range of 80 to 120 ° C. More preferably, the value is in the range of 85 to 115 ° C.

The impregnation time in the step (C) is not particularly limited, but is preferably in the range of 10 minutes to 10 hours. If the impregnation time is shorter than 10 minutes, the impregnation of the foaming agent tends to be insufficient, and if the impregnation time exceeds 10 hours, the productivity tends to decrease. Therefore, from the viewpoint of better balance between the impregnation property of the blowing agent and the productivity, the impregnation time in the step (C) is
More preferably, the value is in the range of 20 minutes to 8 hours.
More preferably, the value is in the range of 30 to 6 hours.

In order to obtain expandable styrene resin particles having more excellent expandability, it is preferable to impregnate a phthalic acid ester together with a blowing agent in the step (C). When the phthalic acid ester is impregnated in this way, the main body of the styrene-based resin particles is appropriately plasticized, so that the foaming agent is easily impregnated and more excellent foamability is obtained.

Further, in the impregnation step of the foaming agent in the step (C), after impregnating the foaming agent or the phthalate,
It is preferable to perform a heat treatment (thermal treatment) in a temperature range of 0 ° C. for 1 to 6 hours. By performing the heat treatment in this manner, the blowing agent and the phthalic acid ester can be sufficiently diffused, and more excellent foaming properties can be obtained.

In the present invention, the order of the step (B) of impregnating the flame retardant and the step (C) of impregnating the blowing agent is not limited, and the step (C) is carried out before the step (B). ) Can also be implemented. Step (B) and step (C)
It is also preferred to carry out simultaneously. This way,
Using a blowing agent, the tetrabromobisphenol A diallyl ether can be more or less dissolved in the blowing agent. Therefore, tetrabromobisphenol A diallyl ether can be more uniformly and easily impregnated into the styrene-based resin particles.

Further, it is preferable that the impregnation of the blowing agent and the flame retardant in the steps (B) and (C) is performed under the condition that the conversion of the styrene monomer is 90% or more. This is because, when added and impregnated in the early stage of polymerization, the particle diameter tends to be large, and the particle size distribution tends to be difficult to adjust. Therefore, it is more preferable to impregnate the foaming agent and the flame retardant when the particle size of the expandable styrene resin particles is substantially determined, that is, when the polymerization rate of the styrene monomer reaches 95% or more.

If desired, a dye can be added at the stage of (B) and step (C). The use of the expandable styrene resin particles can be expanded by coloring the expandable styrene resin particles by adding a dye in this manner. When coloring by adding a dye, it is more preferable to dissolve the dye in a foaming agent in advance and impregnate in step (C). This is because coloring can be performed more uniformly.

Finally, the step (D) of laminating the coating agent on the surface of the expandable styrene resin particle body will be described.
The method of laminating the coating agent is also not particularly limited,
The expandable styrene-based resin particles and a coating agent such as zinc stearate or triglyceride stearate are mixed using a conventionally known means, for example, using a mixer such as a ribbon mixer, a blender, a Henschel mixer, and a Loedige mixer. It can be done by doing. The mixing conditions depend on the type of the mixer. For example, when a 400 liter Henschel mixer is used, the number of rotations is 300.
~ 500 rpm, time 30 ~ 120 seconds, temperature 10 ~ 30
It is preferable to carry out under the condition of ° C.

In the present invention, before the step (D), that is, after the styrene resin particle main body is impregnated with a foaming agent and a flame retardant and dehydrated and dried, it is preferable to laminate the above-mentioned coating agent. By doing so, the adhesion of the coating agent to the styrenic resin particle main body is further improved, blocking of the styrenic resin particles during foaming can be effectively prevented, and generation of static electricity during aging is effectively prevented. Can also be prevented.

[0060]

The present invention will be described in more detail with reference to the following examples. The present invention is not limited by these.

Example 1 (Polymerization Step of Styrene-Based Resin Particles)
Into a 6 liter autoclave, 6000 g of pure water, 9 g of tricalcium phosphate, 0.24 g of sodium dodecylbenzenesulfonate, and 4.2 g of sodium sulfate were respectively charged, and charged while stirring at 200 rpm. Subsequently, while stirring, 4200 g of a styrene monomer and tricyclo [5,2,1,0 ^2.6 ] deca-8-methacrylate were used.
Il (manufactured by Hitachi Chemical Co., Ltd., trade name FA-513M) 900
g, 1,1-bis (tert-butylperoxy)-
3,3,5-trimethylcyclohexane (manufactured by NOF Corporation,
30.0 g of Perhexa 3M), 3.0 g of t-butylperoxyisopropyl carbonate, and 3.0 g of ethylenebisamide were further charged in the autoclave. After completion of the charging, the mixture was heated to raise the temperature in the autoclave from room temperature to 93 ° C.

The temperature in the autoclave was changed to 93
C. for 3 hours, then tricalcium phosphate.
After holding at 0 g and further 4 hours, 6.0 g of tricalcium phosphate was added. Thereafter, the temperature in the autoclave was continuously increased to 110 ° C., and the polymerization was continued for 4 hours to complete the polymerization of the styrene monomer.

After the temperature in the autoclave was lowered to 40 ° C., the slurry was taken out. Next, the slurry was washed, dehydrated, and dried, and then subjected to classification filtration in a range of 12 to 26 mesh to obtain a styrene resin particle main body having an average particle diameter in a range of 0.7 to 1.0 mm in diameter.

(Step of Impregnation with Flame Retardant)
180 g of tetrabromobisphenol A diallyl ether (trade name: 122K, manufactured by Tosoh Corporation), water 3
14 g and 500 g of an aqueous solution comprising 6 g of sodium dodecylbenzenesulfonate were accommodated in a container, and mixed using a homomixer MODEL4D (manufactured by Tokushu Kogyo Co., Ltd.) under the conditions of a rotation speed of about 10,000 rpm for 30 minutes. A flame retardant dispersion was prepared.

Next, the obtained flame retardant dispersion liquid was placed in an autoclave equipped with a stirrer and having a capacity of 16 liters. Further, 6000 g of pure water and 36 calcium tricalcium phosphate were added.
0 g, sodium dodecylbenzenesulfonate 6.0 g
And 6000 g of the styrene-based resin particle main body obtained in the above step were respectively housed in an autoclave.

Next, the temperature inside the autoclave was set to 70 ° C.
Then, 500 g of a softening agent solution prepared in advance was gradually added over 60 minutes. The softener solution was prepared by mixing 90.0 g of toluene, 6.0 g of sodium dodecylbenzenesulfonate, and 404 g of pure water using a homomixer MODEL4D at a rotational speed of about 10,000 rpm.
It was prepared by performing a mixing process under the conditions of a time of 20 minutes.

Next, 480 g of a mixed aliphatic hydrocarbon (propane / butane = 4/6 (weight ratio)) as a foaming agent
Was introduced into an autoclave and pressed into the main body of the styrene resin particles over 60 minutes. And another 60
After maintaining the temperature in the autoclave at 70 ° C for minutes,
The temperature was raised to 120 ° C. over 90 minutes, and the temperature was kept for 8 hours, and then cooled to 40 ° C. At this point, when the slurry obtained in the autoclave was visually observed, no unimpregnated tetrabromobisphenol A diallyl ether was particularly observed.

(Coating Step of Coating Agent) The obtained slurry was taken out of the autoclave, and further washed, dehydrated and dried. Then, the particles were classified using a sieve, and the diameter was reduced to 0.
Expandable styrene resin particles of 7 to 1.0 mm were obtained.

Next, 6000 g of the obtained expandable expandable styrene resin particles were placed in a Henschel mixer, 12.0 g of zinc stearate and 3.0 g of castor oil were added, and the rotation speed was set to 1500 to 2500 rpm.
The mixture was mixed under the conditions of m and 60 seconds and treated with a coating agent to obtain expandable styrene resin particles of the present invention.

(Evaluation of Expandable Styrene Resin Particles) The amount of bromine in the obtained expandable styrene resin particles was measured by the following method. Table 1 shows the results. In addition, tetrabromobisphenol A diallyl ether was added to TB in Table 1
Abbreviated as DAE. Further, using a batch type primary foaming apparatus, the foamable styrene resin particles obtained were foamed until the bulk density became 0.025 g / ml, to obtain primary foamed particles. After aging this at normal temperature and normal pressure for 20 hours,
Further, a flat foamed molded product having a foaming ratio of 40 times (ml / g) was obtained using a molding machine. The molding conditions were a steam pressure of 0.06 MPa, a heating time of 8 seconds, and a double-sided heating time of 10 seconds. Further, a cooling method was employed for cooling.

Table 1 shows the results obtained by measuring the heat shrinkage at 95 ° C. and the self-extinguishing time of the foamed molded article thus obtained as follows. As can be understood from the results in Table 1, the self-extinguishing time shows an excellent value of 2 seconds, and the amount of bromine in the expandable resin particles is an appropriate value of 1.5% by weight. The heat shrinkage at 95 ° C. also showed a small value of −1.8%. Therefore, Example 1
It was confirmed that the foamed molded product of Example 1 had excellent flame retardancy and also had excellent heat resistance. In addition, it was also confirmed that the foamability of the foam molded article of Example 1 when foamed was equivalent to the case where no flame retardant was added.

(1) Measurement of Amount of Bromine The expandable styrene resin particles were burned, and the amount of bromine in the obtained ash was measured by ion chromatography. In addition, it has been found that if the measured amount of bromine is 2.0% by weight or less with respect to the expandable styrene resin particles, the properties such as heat resistance of the expandable styrene resin particles are not practically affected. ing. Further, from the viewpoint of stably obtaining flame retardancy, the amount of bromine in the expandable styrene-based resin particles is set to 0.1%.
The value is more preferably in the range of 7 to 1.5% by weight, and even more preferably in the range of 0.9 to 1.5% by weight.

(2) Measurement of Thermal Shrinkage of Foam Molded Product After foam molding of the foamed molded product, 3 days at a temperature of 60 ° C. and 3 days at room temperature.
Cured each day. Then 100 × 100 × 25
(Mm) was cut into a plate to obtain a test piece. 9
It was left in an atmosphere of 5 ° C. for 168 hours, the dimensions at that time were measured, and the thermal shrinkage (%) of the foam molded article as an index of heat resistance was calculated from the comparison with the dimensions before the test. It is known that there is no practical problem if the measured heat shrinkage is within ± 2.0%, and a value within ± 1.5% is preferable. When the heat shrinkage ratio is a value of + (plus), it indicates that the dimensions of the test piece have expanded after being left in a 95 ° C. temperature atmosphere for 168 hours, and-(minus).
Indicates that the size of the test piece was reduced under the same conditions.

(3) Measurement of self-extinguishing time
Cured each day. Then 100 × 100 × 25
(Mm) was cut into a plate to obtain a test piece. The self-extinguishing time of this test piece was measured in accordance with JIS A9511. The self-extinguishing time must be within 3.0 seconds according to the JIS standard for flame retardancy, and the self-extinguishing time is preferably 2.0 seconds or less.

Example 2 The average particle size of the tetrabromobisphenol A diallyl ether of Example 1 was 7
Expandable styrene resin particles were produced in the same manner as in Example 1 except that the diameter was changed from 0 μm to 90 μm. Then, the amount of bromine in the expandable styrene resin particles obtained in the same manner as in Example 1 was measured. In addition, expandable styrene resin particles were subjected to foam molding in the same manner as in Example 1, and the results of measurement of the heat shrinkage at 95 ° C. and the self-extinguishing time of the obtained foam molded article are shown in Table 1. As can be understood from the results in Table 1, the self-extinguishing time shows an excellent value of 2 seconds, and the amount of bromine in the expandable resin particles is an appropriate value of 1.3% by weight. The heat shrinkage at 95 ° C is also-
The value was extremely small at 1.5%. Therefore, it was confirmed that the foam molded article of Example 2 was excellent in flame resistance and also excellent in heat resistance. In addition, it was also confirmed that the foamability of the foam molded article of Example 2 when foamed was equivalent to the case where no flame retardant was added.

Example 3 The average particle size of the tetrabromobisphenol A diallyl ether of Example 1 was 7
Expandable styrene resin particles were prepared in the same manner as in Example 1 except that the particle size was changed from 0 μm to 100 μm. And
The amount of bromine in the expandable styrene resin particles obtained in the same manner as in Example 1 was measured. In addition, expandable styrene resin particles were subjected to foam molding in the same manner as in Example 1, and the results of measuring the heat shrinkage at 95 ° C. and the self-extinguishing time of the obtained foam molded article are shown in Table 1. As can be easily understood from the results in Table 1, the self-extinguishing time was slightly reduced to 3 seconds, but the amount of bromine in the expandable resin particles was 0.8% by weight.
And the heat shrinkage at 95 ° C. is-
The value was extremely small at 1.3%. Accordingly, it was confirmed that the foam molded article of Example 3 was excellent in flame retardancy and also excellent in heat resistance. In addition, it was also confirmed that the foamability when the foam molded article of Example 3 was foam-molded was equivalent to the case where no flame retardant was added.

Comparative Example 1 The average particle size of the tetrabromobisphenol A diallyl ether of Example 1 was 7
Expandable styrene resin particles were prepared in the same manner as in Example 1 except that the particle size was changed from 0 μm to 150 μm. And
The amount of bromine in the expandable styrene resin particles obtained in the same manner as in Example 1 was measured. In addition, expandable styrene resin particles were subjected to foam molding in the same manner as in Example 1, and the results of measurement of the heat shrinkage at 95 ° C. and the self-extinguishing time of the obtained foam molded article are shown in Table 1. As understood from the results in Table 1, it was found that the foamed molded product of Comparative Example 1 had a long self-extinguishing time of 10 seconds and did not satisfy the flame retardancy standard of JIS A9511.

Comparative Example 2 Expandable styrene resin particles were produced in the same manner as in Example 1 except that liquid tetrabromoethane was used instead of the tetrabromobisphenol A diallyl ether of Example 1. Then, the amount of bromine in the expandable styrene resin particles obtained in the same manner as in Example 1 was measured. In addition, expandable styrene resin particles were subjected to foam molding in the same manner as in Example 1, and the results of measurement of the heat shrinkage at 95 ° C. and the self-extinguishing time of the obtained foam molded article are shown in Table 1. In Table 1, tetrabromoethane is abbreviated as TBE. As understood from the results in Table 1, the amount of bromine in the expandable resin particles was as large as 2.7% by weight, and the amount of bromine in the expanded molded article was 95%.
The heat shrinkage at ℃ also showed a large value of -4.0%.
Further, there was also a problem that tetrabromoethane is liquid at room temperature and is difficult to handle. In addition, the foaming property at the time of molding the foamed molded article also tended to be lower than when the flame retardant was not added.

[0079]

[Table 1]

[0080]

According to the present invention, a foam molded article having excellent flame retardancy and a small heat shrinkage at a high temperature (95 ° C.) without impairing the foamability of the expandable styrene resin particles, It is possible to provide expandable resin particles from which such a foam molded article can be obtained. Further, the Akukuriru acid tricyclo [5,2,1,0 ^2.6] dec-8-yl and methacrylic acid tricyclo [5,2,1,0 ^2.6] dec-8-yl, by specifying the amount used as a monomer, The present invention can provide a foamed molded product exhibiting more excellent flame retardancy and a low heat shrinkage value, or an expandable resin particle from which such a foamed molded product can be obtained. The foamed molded product obtained from the expandable styrene resin particles of the present invention is a heat insulating material for solar, a heat insulating material for a hot water supply tank, a heat insulating material for a metal roof, a heat insulating material for a feeding container, a heat insulating material for a vehicle ship, a hot water. It can be widely used for applications requiring flame retardancy and heat resistance, such as heat insulating materials for pipes, sizing boards, structural materials for automobiles, and materials for panels formed simultaneously with metals.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08F 220: 18)

Claims (10)

[Claims] 1. An expandable styrene-based resin particle comprising a styrene-based resin particle body containing a foaming agent, wherein tetrabromobisphenol A diallyl ether having an average particle diameter of 120 μm or less is used. Flame-retardant expandable styrene resin particles impregnated in a range of 1.0 to 5.0% by weight based on the total amount of A diallyl ether. 2. The flame-retardant expandable styrenic resin particles according to claim 1, wherein tricyclo [5,2, acrylate] is used with respect to the total weight of the monomers when the styrene-based resin particles are polymerized. 1,0 ^2.6 ] dec-8-yl and tricyclo [5,2,1,0 ^2.6 ] dec-8-methacrylate or any one of which has a flame retardancy of 5 to 45% by weight. Expandable styrene resin particles. 3. The expandable styrenic resin particles having flame retardancy according to claim 1 or 2, wherein styrene is added in an amount of 50 to 80% by weight based on the total weight of the monomers used for polymerizing the main body of the styrene type resin particles. % Foamable styrenic resin particles having a flame retardancy value in the range of%. 4. The flame-retardant expandable styrene-based resin particles according to claim 1, wherein α is relative to the total weight of the monomer when polymerizing the styrene-based resin particle body. Foamable styrenic resin particles having flame retardancy with methylstyrene being a value within the range of 5 to 45% by weight. 5. The foamable styrenic resin particles having flame retardancy according to claim 1, wherein the foaming agent is a volatile volatile foaming agent, and the volatile volatile foaming agent is contained. Flame-retardant expandable styrene-based resin particles having an amount of 3 to 10% by weight based on the total amount of the styrene-based resin particle main body and the easily volatile blowing agent. 6. The method for producing flame-retardant expandable styrene resin particles according to any one of claims 1 to 5, comprising the following steps (A) to (C). For producing expandable styrene resin particles having flame retardancy. (A) A step of polymerizing a styrene-based monomer to produce a styrene-based resin particle main body. (B) The average particle diameter of the styrene resin particles is 120
μm or less of tetrabromobisphenol A diallyl ether is added to the total amount of the styrene resin particles and tetrabromobisphenol A diallyl ether in an amount of 3 to
Impregnating in the range of 10% by weight. (C) a step of impregnating the styrenic resin particle body with a foaming agent. 7. The method for producing expandable styrenic resin particles having flame retardancy according to claim 6, comprising the step of: (D) coating the surface of the styrenic resin particle main body with a coating agent. A method for producing expandable styrene-based resin particles having: 8. The method for producing expandable styrene-based resin particles having flame retardancy according to claim 6 or 7, wherein tetrabromobisphenol A diallyl ether is impregnated with a dispersant. Manufacturing method. 9. The method for producing expandable styrene resin particles having flame retardancy according to any one of claims 6 to 8, wherein step (B) and step (C) or any one of step (B) and step (C) are performed in the same manner.
A method for producing expandable styrenic resin particles at a temperature in the range of 0 to 125 ° C. 10. The method for producing expandable styrene resin particles having flame retardancy according to claim 6, wherein the step (B) and the step (C) are simultaneously performed. A method for producing expandable styrene-based resin particles having: