JPS6217616B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to flame retardant expandable styrenic resin bead compositions. More specifically, in the present invention, styrene resin beads contain a blowing agent, and 2,2-
A flame-retardant expandable styrenic bead composition formed by adhering and impregnating bis(4-allyloxy-3,5-dibromophenyl)propane with a phosphoric acid ester that is liquid at room temperature or a halogenated paraffin that is liquid at room temperature. . Styrenic resins are used in a wide variety of fields and applications, such as ornaments, building materials, daily necessities, buildings, and structures. In particular, in recent years, expanded styrene resins have come to be used in large quantities as industrial and architectural insulation materials from the viewpoint of energy conservation. This foamed styrene resin is generally manufactured by two methods: extrusion foaming method and bead foaming method. The extrusion foaming method is a method of manufacturing foam molded products by mixing styrene resin and a foaming agent in an extruder and then extrusion molding, while the bead foaming method first involves impregnating styrene resin beads with a foaming agent. This is a method of producing foamed beads by heating and foaming the foamed beads in a mold such as a metal mold. However, styrene resin is flammable, and if it ignites or burns, the danger is unimaginable. For this reason, it is desired to make foamed styrene resins used for insulation materials etc. flame retardant, and many proposals have already been made, some of which have actually been commercialized. For example, to make styrene foam resin flame retardant by the extrusion foaming method, 2,2-bis(4-allyloxy-3,5-dibromophenyl)propane (JP-A-53-125457) and hexabromo are used as flame retardants. Cyclododecane (Japanese Patent Publication No. 43-29658), pentabromomonochlorocyclohexane (Japanese Patent Publication No. 36-6683), and the like are known. Among these, especially 2,
2-Bis(4-allyloxy-3,5-dibromophenyl)propane exhibits a unique flame retardant effect on styrene resins, so it can be used in smaller amounts than other flame retardants. It has the advantage that there is little deterioration in the physical properties of the resin. In flame retardation using this extrusion foaming method, the flame retardant and molten resin are kneaded in an extruder, so any amount of flame retardant can be used, and there is no particular restriction on the amount based on reasons specific to the mixing method. . However, in this method, there are restrictions on the amount of flame retardant used due to reasons such as deterioration of resin properties. On the other hand, when making styrene foam resin flame retardant using the bead foaming method, 2-chloro-1,
2,3,4-tetrabromobutane (Special Publication 1977-
23091), bis(dichloropropyl) dichloropropyl phosphate (Japanese Patent Publication No. 44-16213), tribromphenyl dibromopropyl ether (Japanese Patent Publication No. 48-32575), tris(2,
3-dibromopropyl) phosphate (Special Publication No. 33
-6788 Publication) etc. have been proposed. Flame retardant beads in this method are generally made by adding flame retardants and blowing agents during the process of polymerizing styrenic monomers into bead-shaped polymers, or by adding flame retardants and blowing agents to beads produced by suspension polymerization. An impregnation method is used. However, since these methods are usually carried out at temperatures below 100°C, flame retardants are limited to those with a melting point of 100°C or below. By the way, 2,2-bis(4
-Aryloxy-3,5-dibromophenyl)propane has an excellent flame retardant effect on styrene resins, and even if it is attempted to adhere to and impregnate styrene resin beads by the impregnation method, it will not work if a specified amount is applied. It is difficult to adhere and impregnate, making it difficult to obtain the desired flame retardant beads. One possible method to improve this point is to raise the treatment temperature to around the melting point of the flame retardant, but this method has disadvantages in terms of equipment and economy, and also has the disadvantage that it is difficult to obtain stable and uniform beads. In addition, the flame retardants proposed above need to be added in relatively large amounts to styrene resins, have poor weather resistance and heat resistance, or are highly toxic. It cannot be put into practical use with satisfactory results. The present inventor paid attention to this point, and made 2,2-bis(4-allyloxy-3,5-dibromophenyl)
As a result of intensive studies on making styrene resin beads flame retardant using propane, we found that 2,2-bis(4-allyloxy-3,5-dibromophenyl)propane was used together with a specific phosphate ester or halogenated paraffin. The present invention was achieved based on the finding that the desired flame-retardant expandable polystyrene resin beads can be obtained by using the method. That is, the present invention provides styrene resin beads with (i)
Foaming agent in the amount imparting foaming properties, (ii) 2,2 in the amount imparting flame retardancy
bis(4-allyloxy-3,5-dibromophenyl)propane, and (iii) the styrenic resin beads
The present invention relates to a flame-retardant expandable styrenic resin bead composition containing 0.05 to 2 parts by weight per 100 parts by weight of a phosphoric acid ester that is liquid at room temperature and/or a halogenated paraffin that is liquid at room temperature. The styrenic resin beads used in the present invention are beads of styrene polymers and copolymers of styrene and other addition polymerizable monomers such as methylstyrene, acrylonitrile, methyl methacrylate, methyl acrylate, and the like. Such beads can be easily obtained, for example, from commercially available styrene resin beads. Further, examples of the blowing agent to be included in the styrene resin beads in the present invention include propane, butane, pentane, cyclohexane, dichlorodifluoromethane, and the like. In addition to these, agents known as foaming agents for styrene resin beads can also be used. Moreover, one or more types of these can be used. Such a blowing agent can be incorporated by adding it during polymerization of styrenic resin, for example by adding it to the monomer before polymerization or to the reaction system during polymerization, or by impregnating it after producing styrenic resin beads. I can do it. These methods are well known methods for producing expandable beads. Furthermore, in the present invention, the flame retardant 2,2-bis(4
-Allyloxy-3,5-dibromophenyl)propane that is normally commercially available can be used. This 2,2-bis-(4-allyloxy-
3,5-dibromophenyl)propane is usually obtained by reacting tetrabromobisphenol A with allyl chloride in an amount ranging from 2 times the mole to a slightly excess amount. Furthermore, the phosphoric acid esters that are liquid at room temperature and are used together with the flame retardant in the present invention include, for example, tricresyl phosphate, trisisopropylphenyl phosphate, tributyl phosphate, triethyl phosphate, trioctyl phosphate, trichloroethyl phosphate, Examples include trisdichloropropyl phosphate, tributoxyethyl phosphate, tris-β-chloropropyl phosphate, and octyldiphenyl phosphate. One or more types of these can be used. Further, as the halogenated paraffin which is liquid at room temperature and is used together with the flame retardant, chlorinated paraffin such as chlorinated paraffin having a chlorine content of 40, 45, 50 or 65% is preferably mentioned. One or more types of these can be used. Phosphate esters that are not liquid at room temperature (e.g., triphenyl phosphate) or halogenated paraffins that are not liquid at room temperature (e.g., chlorinated paraffins with a chlorine content of 70% or more) are added to styrene resin beads in a desired amount of 2,2-bis( 4-Allyloxy-3,5-
The effect of containing (dibromophenyl)propane is small and is not useful. The expandable styrenic resin bead composition of the present invention includes styrenic resin beads, a blowing agent, 2,2-bis(4-allyloxy-3,5-dibromophenyl)propane, and a phosphate ester that is liquid at room temperature. It can be obtained by containing/or halogenated paraffin, but the amount of blowing agent is the amount that imparts foaming properties to the beads, and is usually 3 to 15 parts by weight, preferably 5 parts by weight, per 100 parts by weight of styrene resin beads.
~7 parts by weight, and the amount of 2,2-bis(4-allyloxy-3,5-dibromophenyl)propane is an amount that imparts flame retardancy to the beads, usually 100 parts by weight of styrene resin beads. 0.5 to 5 parts by weight, preferably 0.8 to 2 parts by weight. If the amount of 2,2bis(4-allyloxy-3,5-dibromophenyl)propane exceeds 5 parts by weight, the physical properties of the expanded styrene resin will greatly deteriorate. The amount of phosphoric acid ester and/or halogenated paraffin that is liquid at room temperature is 0.05 to 2 parts by weight per 100 parts by weight of styrene resin beads. In amounts less than 0.05 parts by weight, 2,2-bis(4-allyloxy-3,5-
The effect of increasing the amount of adhesion and impregnation of (dibromophenyl)propane is small, and if the amount is more than 2 parts by weight, the physical properties of the styrenic resin foam will be greatly deteriorated, which is not preferable. The weight ratio of 2,2-bis(4-allyloxy-3,5-dibromophenyl)propane to the phosphoric acid ester and/or halogenated paraffin that is liquid at room temperature is preferably about 20:1 to 2:1, 10:1
A ratio of about 10:3 to 10:3 is particularly preferred. 2,2-bis(4-allyloxy-3,5-dibromophenyl) was used in combination with a phosphoric acid ester and/or a halogenated paraffin, which is liquid at room temperature.
Almost the entire amount of propane can be attached and impregnated onto the beads. 2,2-bis(4-allyloxy-
3,5-Dibromophenyl)propane and the phosphoric acid ester and/or halogenated paraffin that are liquid at room temperature may be used after mixing them in advance, or they may be used by adding them separately. good. The flame-retardant expandable styrenic resin bead composition of the present invention is usually prepared in an autoclave in an aqueous dispersion system including styrenic resin beads, 2,2-bis(4-allyloxy-3,5-dibromophenyl)propane and A method in which phosphoric acid ester and/or halogenated paraffin, especially chlorinated paraffin, which is liquid at room temperature is charged and impregnated at about 100°C with a blowing agent under pressure, or a water suspension and catalyst (peroxide) in an autoclave.
A styrenic monomer, 2,2-bis(4-allyloxy-3,5-dibromophenyl)propane, and a phosphoric acid ester liquid at room temperature and/or a halogenated paraffin, especially a chlorinated paraffin, are further added if necessary. It can be produced by a suspension polymerization method in which a blowing agent is charged and heated to carry out a polymerization reaction of a styrenic monomer, and a blowing agent is press-injected before and after the polymerization reaction. The former impregnation method is particularly preferred. The flame-retardant expandable styrenic resin bead composition of the present invention may further contain other additives such as metal oxides, antioxidants, fillers, dyes, and stabilizers, if necessary. can. Further, the present invention will be explained with reference to examples. The oxygen fat numbers in the examples are the results of measurements according to the method of ASTMD-2863. Example 1 In an autoclave with a capacity of 10, 3 kg of water, 1 kg of polystyrene beads, 12 g of 2,2-bis(4-allyloxy-3,5-dibromophenyl)propane, and 1.4 g of tricresyl phosphate were charged, and after heating to 100°C, Butane gas was pressurized until the pressure reached approximately 10 kg/cm ³ .
After stirring for about 6 hours, the foaming beads were removed by cooling and pressure release, washed with water, and then dried at room temperature. 1/10 part by weight of the obtained expandable beads was heated at 80℃ for 5 minutes.
After drying under reduced pressure for hours and removing the foaming agent and moisture, the weight is 101.30g, and this value is converted to the total amount.
The total amount was 1013.0 g, and 97% of the total amount of 13.4 g of 2,2-bis(4-allyloxy-3,5-dibromophenyl)propane and tricresyl phosphate added was attached to and impregnated with the polystyrene beads. The obtained expandable beads were foam-molded in a conventional manner to obtain a polystyrene foam having a density of 0.033 g/cm ³ . A test piece of 200 x 25 x 10 mm was cut from this foam and subjected to a combustion test according to JIS-A-9551. As a result, the combustion time was 1.2 seconds and the test piece passed the test. Comparative Example 1 The same procedure as in Example 1 was carried out except that tricresyl phosphate was not added. As a result, the weight of 1/10 part by weight of the obtained expandable beads after drying was 100.54 g, and this value was added to the total amount. When converted, it becomes 1005.4g,
The adhesion and impregnation rate on polystyrene beads was 45%. Similar to Example 1, foam molding was performed to obtain a density of 0.030.
A foam of g/cm ³ was obtained. This foam has a burn time of
The judgment was failed in 3.7 seconds. This result shows that tricresyl phosphate significantly increases the amount of adhesion and impregnation of the flame retardant. Examples 2 to 8 Using the same equipment and method as in Example 1, changing the amount of tricresyl phosphate added as shown in Table 1, or adding other phosphate esters or chlorinated paraffin (chlorine content: 40 %) was used to produce expandable beads. A foam was obtained in the same manner as in Example 1 using these expandable beads. Table 1 shows the amount and percentage of impregnation attached to the foam beads, as well as the flame retardancy (burning time) of the foam.

[Table] From the above table, when phosphate ester or chlorinated paraffin is used together, 2,2-bis(4-allyloxy-
It can be seen that the adhesion and impregnation rate of 3,5-dibromophenyl)propane can be significantly increased and a flame-retardant expandable bead composition can be obtained.

Claims (1)

[Scope of Claims] 1 Styrenic resin beads, (i) a foaming agent in an amount that imparts foamability, and (ii) an amount of 2,2-bis(4-allyloxy-3,5-dibromophenyl) that imparts flame retardancy. ) propane, and (iii) per 100 weight of said styrenic resin beads.
A flame-retardant expandable styrenic resin bead composition containing 0.05 to 2 parts by weight of a phosphoric acid ester that is liquid at room temperature and/or a halogenated paraffin that is liquid at room temperature. 2. Claim 1, characterized in that the content of 2,2-bis(4-allyloxy-3,5-dibromophenyl)propane is 0.5 to 5 parts by weight per 100 weight of styrene resin beads. Composition of.