JPS5841302B2 - Expandable polystyrene resin composition with flame retardancy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a foamable polystyrene resin composition having flame retardancy due to self-extinguishing.

Expandable polystyrene resin moldings containing halogen compounds have been widely used as materials for building materials, wall materials, etc. because they have self-extinguishing properties.

Conventionally, bromine compounds have been particularly used as halogen compounds added to expandable polystyrene resins, such as tetrabromobisphenol A1 hexabromocyclododecane,
Pentabromomonochlorocyclohexane was known.

These components can be dissolved in the resin monomer during suspension polymerization and added at the beginning of the polymerization, added when a certain degree of polymerization conversion has been reached, or added to the extrusion molding machine together with the resin. They were processed into resin beads by applying flame-retardant treatment such as dispersing them in resin.

However, although the resin beads synthesized in this manner are endowed with flame retardancy, they have various drawbacks as described below.

In other words, when conventional processing methods are used, in addition to requiring complicated operations to make the resin beads flame retardant, adding a flame retardant to polystyrene resin generally changes the fluidity of the resin and increases the melting temperature. If a large amount of high flame retardant is added, part of the flame retardant will bleed during foam molding, limiting fusion bonding.On the other hand, if a flame retardant with a low melting temperature is used, moldability will decrease. .

Furthermore, when synthesizing resin beads by suspension polymerization or bulk polymerization, if a bromine compound is added to the monomer prior to polymerization, it will inhibit the polymerization reaction, which will cause a decrease in productivity. It acts as a transfer agent and may have a lower molecular weight than the desired resin beads.

In addition, when foaming resin beads, the bromine compound exhibits a nucleation effect, which may cause the size of the closed cells in the foamed beads to become too small, which has the disadvantage of causing a decline in the physical properties of the molded product. be.

The present invention provides expandable polystyrene resin beads that have low polymerization inhibition during polymerization, no decrease in molecular weight, good fusion properties in molded products, excellent moldability, and flame retardancy (self-extinguishing properties). In order to achieve this purpose, the present invention is characterized by using 5BR (styrene-butadiene rubber) bromide as a flame retardant.

That is, the present invention is a flame-retardant foamable polystyrene-based resin composition in which a bromide of SBR is contained in the structure of the foamable polystyrene-based resin to form beads.

The polystyrene resin used in the present invention includes polymers such as styrene, α-methylstyrene, dimethylstyrene, chlorostyrene, copolymers thereof, and copolymers of these with vinyl monomers such as butadiene, acrylonitrile, and methyl methacrylate. In addition to polymers, all polyolefins containing polystyrene are included.

As a foaming agent, it can be used without dissolving the above resin, and
A compound having a boiling point lower than the softening point of the resin is used.

For example, aliphatic hydrocarbons such as propane, butane, isobutane, pentane, neopentane hexane, methyl chloride, tetrachlorethylene, etc., halogenated hydrocarbons such as methyl chloride, tetrachlorethylene, etc. can be used. .

During or after the production of resin beads, 3 to 15% of these foaming agents are added to the resin structure to produce foamable resin beads.

In addition to the above-mentioned foaming agents, softeners such as toluene, xylene, and ethylbenzene may also be used, and additives such as plasticizers and lubricants may be added as necessary.

The flame retardant used in the present invention is a brominated product of SBR, and can be easily obtained by brominating liquid SBR.

The proportion of bromine to the total molecular weight of bromide is 50-80%
The degree is appropriate.

The amount of bromide added is 0.1 to 3 to the above foamable resin.
．． The proportion is 0% by weight, preferably 0.3-1.0% by weight.

In addition, in order to increase the flame retardant effect, a flame retardant additive of 0.01 to 2
．． It may be blended in a proportion of 0% by weight, preferably 0.1 to 0.5% by weight.

Here, dicumyl peroxide, 2.5 is added as a flame retardant aid.
Organic peroxides such as -dimethyl-2,5-di(tert-butylperoxy)hexane are used, but are not limited thereto.

The above-mentioned flame retardants and flame retardant aids can be added prior to producing the resin beads, during production, or at any stage after production.

The present invention processes the above-mentioned components into foamable polystyrene beads by a conventional method. By foaming the obtained beads in a mold, the mutual fusion properties of the foamed beads are improved.
A foamed polystyrene molded product having excellent moldability and flame retardancy can be obtained.

In the present invention, a brominated product of SBH is particularly selected as a flame retardant to be added to a foamable polystyrene resin composition, and it can be easily obtained by brominating liquid SBR.
Of course, solid SBR can also be used after being brominated.

As mentioned above, adding a flame retardant to polystyrene resin changes the fluidity of the resin, and if a large amount of flame retardant with a high melting temperature is added, part of it bleeds during foam molding, causing fusion. On the other hand, when a flame retardant with a low melting temperature is used, the moldability decreases.However, brominated SBR does not have this drawback and significantly improves the fusion and moldability of foamed beads. It has an excellent effect that can improve the quality of the product.

In addition, even if the brominated product of SBR is added to the monomer prior to polymerization, it is not observed to act as a chain transfer agent during the polymerization reaction, and it has little polymerization inhibiting property (i.e., a composition without a decrease in molecular weight can be obtained). be able to.

When using ordinary flame retardants, in order to increase the molecular weight of the composition, that is, to increase its physical strength, it is necessary to reduce the amount of polymerization initiator and react for a long time, or to lower the temperature of polymerization and slow the reaction. It is necessary to polymerize with SB
By using the bromide of R, this operation is completely unnecessary and the operation is exactly the same as when no flame retardant is included.
Therefore, productivity can be significantly improved.

Furthermore, according to the present invention, when the beads are foamed, the size of the closed cells in the foamed beads does not become too small, and the size can be freely controlled, making it possible to obtain molded products with desired physical properties. The scope of use can be greatly expanded.

The present invention will be explained in detail below.

Example 1 Deionized water 18 in a 51 autoclave with a stirrer
5 (1. Add 5.0 oz of tricalcium phosphate, 0.06 P of sodium dodecylbenzenesulfonate and stir, then 3.51 oz of benzoyl peroxide, tert-butyl perbenzony) 1. FM', liquid 5BR (Idemitsu Petrochemical's C8-15) bromide (Br content 70.4%) 7.5
150 (l) of a styrene monomer solution containing f was added and thoroughly dispersed, and the temperature was raised to 90°C.

After holding this at 90°C for 6 hours, polyvinyl alcohol (Nippon Gosei Kagaku: Gohsenol GH-17)
2.0? , dodecylbenzenesulfonic acid sorter 0.1
? , calcium carbonate 6, Oi were added, and after sealing the autoclave, Normanpentane 125P was pressurized into the autoclave, kept at 90°C for 2 hours, then heated to 110°C, and impregnated for 10 hours.

Thereafter, the mixture was cooled to room temperature to obtain expandable polystyrene beads.

After confirming that the aging process was completed, the beads were pre-foamed at a bulk foaming ratio of 40 times, and after being left for day and night, the beads were foamed at 30c/rL.
It was processed into a molded product using a mold of ×30C1rL×5crIL.

Table 1 shows the test results for this molded article.

The evaluation items in Table 1 were obtained according to the following method.

(1) Fusion property: The state of fusion between the foam beads on the fractured surface of the molded product was observed.

(2) Relative viscosity: After refining the resin beads according to a conventional method, make a 1% toluene solution, and use an Uberote viscometer to calculate the falling time of this solution at 30 ± 0.1°C and the falling time of toluene. This value was determined by the ratio.

(3) Burning time: In accordance with the method of JIS-A-9511, the time from removing the fire source to extinguishing the fire was shown as the average value of 5 tests, and the pass/fail was determined.

Example 2 In Example 1, liquid SBR bromide was added to 15.0
A test was conducted on a molded article obtained by the same method as in the example※※ except that P was used.

The measurement results are shown in Table-1.

Comparative Example In Example 1, monochloropentabromocyclohexane was used instead of the liquid brominated SBR.
0'? A test was conducted on a molded article obtained by the same method as in Example 1, except for the addition of the compound.

The measurement results are shown in Table-1. Comparative Example 2 A test was conducted on a molded article obtained by the exact same method as in Example 1, except that 3.1' of hexabromocyclododecane was added instead of using liquid SBH bromide. I did it.

The measurement results are shown in Table-1. Comparative Example 3 In Example 1, a test was conducted on a molded article in which no bromide of liquid SBR was added.

The measurement results are shown in Table-1.

Claims (1)

[Claims] 1. A foamable polystyrene resin composition having flame retardancy, characterized in that a bromide of SBR is contained in the structure of the foamable polystyrene resin.