JPH0611856B2 - Flame-retardant polyphenylene ether resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyphenylene ether resin composition having excellent flame retardancy and heat resistance, and having less migration of halogenated compounds.

Polyphenylene ether is a resin that excels in various properties such as heat resistance and rigidity, and has attracted attention as an engineering plastic, but it cannot be said to have sufficient flame retardancy by itself. Further, polyphenylene ether is insufficient in workability and impact resistance, and various techniques for blending polystyrene or elastomer-reinforced polystyrene and various elastomers have been proposed for the purpose of improving this point (US Pat. No. 33).
83435, etc.).

However, it is well known that the flame retardancy of a polyphenylene ether composition obtained by blending it with polystyrene or an elastomer is significantly reduced. Therefore, for applications requiring flame retardancy, it is necessary to add a flame retardant to a blend of polyphenylene ether, especially polyphenylene ether and various modifiers, and many techniques using various flame retardants have been proposed. There is. Among them, phosphoric acid esters are effective flame retardants for polyphenylene ethers. For example, various phosphoric acid esters are disclosed in JP-B-53-418, and aromatic compounds are disclosed in JP-A-53-73248. Group phosphoric acid esters, and further, JP-A-49-32947 proposes the combined use of phosphoric acid esters and antimony trioxide.

However, it is also true that the use of phosphoric acid esters significantly lowers the heat resistance, which is one of the excellent characteristics inherent in polyphenylene ether. For example, when an aromatic phosphoric acid ester is added to a composition composed of polyphenylene ether and a polystyrene resin, the heat distortion temperature is likely to be lowered by about 3 ° C. even if only 1 part by weight is added, and its improvement is strongly desired. Be done.

On the other hand, there are some known techniques for adding an aromatic halogen compound in order to impart flame retardancy to polyphenylene ether or its composition. For example, JP-A-48-7945 teaches a method of adding hexabromobenzene and antimony, and JP-B-46-11572 and JP-A-52-57.
No. 255 discloses a method of adding a similar aromatic halogen compound. However, when these low molecular weight aromatic halogen compounds are used, the compounds tend to migrate from the inside of the molded article to the surface, and therefore these compounds are liable to cause blooming and further have toxicity. It is a well-known fact among those skilled in the art that the work environment is deteriorated due to the volatilization of the compound, and the improvement is also desired.

An object of the present invention is to provide a resin composition which can effectively improve the flame retardancy of a polyphenylene ether, or a composition comprising a polyphenylene ether and a polystyrene resin, and overcome various drawbacks of the above-mentioned prior art. Especially.

The object of the present invention is: (a) 50 to 99% by weight of polyphenylene ether or a mixture of polyphenylene ether and polystyrene resin, and (b) a number average molecular weight of 5000.
Brominated polystyrene having a bromine content of 67% by weight or more, obtained by brominating 0 or more polystyrene
Achieved with a resin composition consisting of wt%.

The polyphenylene ether used in the flame-retardant polyphenylene ether-based resin composition of the present invention has the general formula
(II) a polyphenylene ether obtained by polycondensing one or more monocyclic phenols, (Here, R ₁ is a lower alkyl group having 1 to 3 carbon atoms, R ₂ and R ₃ are hydrogen atoms or a lower alkyl group having 1 to 3 carbon atoms, and at least one ortho position of the hydroxyl group must be a lower alkyl group. Substituents must be present.) Alternatively, a graft copolymer having a polyphenylene ether as a base, which is obtained by graft-polymerizing a vinyl aromatic compound to the polyphenylene ether, is included. This polyphenylene ether may be a homopolymer or a copolymer.

The monocyclic phenol represented by the general formula (I),
For example, 2,6-dimethylphenol, 2,6-diethylphenol, 2,6-dipropylphenol, 2-methyl-6-ethylphenol, 2-methyl-6-propylphenol, 2-ethyl-6-propylphenol. ,
m-cresol, 2,3-dimethylphenol, 2,3
-Diethylphenol, 2,3-dipropylphenol, 2-methyl-3-ethylphenol, 2-methyl-
3-propylphenol, 2-ethyl-3-methylphenol, 2-ethyl-3-propylphenol, 2-propyl-3-methylphenol, 2-propyl-3-ethylphenol, 2,3,6-trimethylphenol,
2,3,6-triethylphenol, 2,3,6-tripropylphenol, 2,6-dimethyl-3-ethyl-
Examples include phenol and 2,6-dimethyl-3-propylphenol. Examples of the polyphenylene ether obtained by polycondensation of one or more of these phenols include poly (2,6-dimethyl-1,4-phenylene) ether and poly (2,6-diethyl-1,4).
-Phenylene) ether, poly (2,6-dipropyl-)
1,4-phenylene) ether, poly (2-methyl-6)
-Ethyl-1,4-phenylene) ether, poly (2-
Methyl-6-propyl-1,4-phenylene) ether, poly (2-ethyl-6-propyl-1,4-phenylene) ether, 2,6-dimethylphenol / 2,
3,6-trimethylphenol copolymer, 2,6-dimethylphenol / 2,3,6-triethylphenol copolymer, 2,6-diethylphenol / 2,3,6-trimethylphenol copolymer, 2, 6-dipropylphenol / 2,3,6-trimethylphenol copolymer,
A graft copolymer obtained by graft-polymerizing styrene to poly (2,6-dimethyl-1,4-phenylene) ether,
Examples thereof include a graft copolymer obtained by graft-polymerizing styrene to a 2,6-dimethylphenol / 2,3,6-trimethylphenol copolymer. In particular, poly (2,6-dimethyl-1,4-phenylene) ether, 2,6-dimethylphenol / 2,3,6-trimethylphenol copolymer, and a graft copolymer obtained by graft-polymerizing styrene to the former two. Coalescence is preferred as the polyphenylene ether used in the present invention.

Next, the polystyrene resin used in the composition of the present invention is a resin containing at least 25% by weight or more of the structural unit represented by the following general formula (III) in the polymer, (In the formula, R ₄ represents a hydrogen atom or a lower alkyl group, Z represents a halogen atom or a lower alkyl group other than bromine, and p represents
Is 0 or a positive integer of 1 to 3. ) For example, polystyrene, high impact polystyrene, styrene-butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-α-methylstyrene copolymer, styrene-maleic anhydride copolymer, styrene-p-methylstyrene copolymer, poly-
Examples thereof include p-methylstyrene and impact resistant poly-p-methylstyrene. Among them, impact-resistant polystyrene is preferably used, and polybutadiene and butadiene-
It includes rubber-modified polystyrene modified with a rubber component such as styrene copolymer rubber and EPDM. When a composition comprising polyphenylene ether and polystyrene resin is used, the compounding ratio of both is not particularly limited, but the polyphenylene ether is usually 5 based on the sum of both.
It is desirable to occupy the range of up to 95% by weight.

Further, the brominated polystyrene used in the composition of the present invention has a bromine content of 67% by weight or more. The brominated polystyrene is a resin obtained by brominating polystyrene having a number average molecular weight of 50,000 or more, preferably 70,000 or more, and most preferably 130000 or more. For example, desired polystyrene is converted into carbon tetrachloride or chloroform. It can be produced by dissolving it in a solvent such as and reacting bromine directly in the presence or absence of a catalyst such as iron powder or iodine. For such a bromination method, for example, Journal of Organic
Chemistry. Volume 12, Pages 108 (1947
, And in US Pat. No. 4,35.
No. 2,909 teaches a method of brominating by reacting bromine chloride in the presence of a catalyst such as antimony chloride in the presence of a chlorinated hydrocarbon as a solvent. Listed as a reference to explain the brominated polystyrene used in. Such brominated polystyrene is sold, for example, under the trade name of "Pyrotiec 68PB" by Fero USA, and can be easily obtained commercially.

By the way, the brominated polystyrene used in the present invention is specific as a flame retardant compounded in a polyphenylene ether or a resin composition containing the same. That is, not only imparting excellent flame retardancy to polyphenylene ether, or a resin composition containing the polyphenylene ether, but because of good compatibility and migration due to its structure and molecular weight, conventionally known flame retardants are used. It does not cause the deterioration of various physical properties that occurred when the user was in the room. Further, it is also specific that the brominated polystyrene can be used in combination with a phosphoric acid ester or an antimony compound without substantially impairing the original characteristics of polyphenylene ether or a composition containing the same. Above all, when used in combination with an antimony compound, a more excellent flame retardant effect is exhibited.

In the polyphenylene ether resin composition of the present invention, the brominated polystyrene should be blended in an amount of 1 to 50% by weight in the total composition.

In preparing the polyphenylene ether-based resin composition of the present invention, any known method is used for mixing the polyphenylene ether and the brominated polystyrene-based compound, which are the composition components, with the polystyrene-based resin as desired. Alternatively, for example, a method of mechanically mixing using a roll mill, a Banbury mixer, an extruder, or the like, or a method of mixing a solution or suspension of the above components may be appropriately adopted.

In the composition of the present invention, if desired, other additives such as other flame retardants, flame retardant aids, elastomer components, stabilizers, UV absorbers, plasticizers, lubricants, etc .; pigments; fillers; other components Can be appropriately blended.

Examples of flame retardants include triphenyl phosphate, tricresyl phosphate, phosphates obtained from a mixture of isopropylphenol and phenol, bifunctional phenols such as benzohydroquinone and bisphenol A, and other alcohols or phenols. Phosphoric acid esters such as obtained polyphosphates; bromine-containing compounds represented by decabromobiphenyl, pentabromotoluene, decabromobiphenyl ether, hexabromobenzene and the like can be mentioned. Examples thereof include antimony, boron, zinc- or iron-containing compounds.

The elastomer component is an elastomer in a general sense, for example, AV Tobolsky's "Properties and St.
ructures of Polymers "(John Wiley & Sons. Inc., 19
60 years) The definition adopted on pages 71-78 can be quoted, and elastomer has a Young's modulus at room temperature of 10 ⁵ ~
It means a polymer having 10 ⁹ dynes / cm ² (0.1 to 1020 kg / cm ² ). Specific examples of the elastomer include AB
-A 'type elastomeric block copolymer, A-B-A' type elastomeric block copolymer in which a double bond of a polybutadiene portion is hydrogenated, polybutadiene, polyisoprene, a diene compound and a vinyl aromatic compound Copolymer, nitrile rubber, ethylene-propylene copolymer, ethylene-propylene-diene copolymer (EPDM) thiochol rubber, polysulfide rubber, acrylic rubber, polyurethane rubber, grafted product of butyl rubber and polyethylene, polyester elastomer, etc. Is mentioned. In particular, an ABA 'type elastomeric block copolymer is desirable. The terminal blocks A and A'of this block copolymer are polymerized vinyl aromatic hydrocarbon blocks, B is a polymerized conjugated diene block, and B is a polymerized conjugated diene block.
Desirably, the molecular weight of the blocks is greater than the combined molecular weight of the A and A'blocks. The terminal blocks A and A'may be the same or different, and the blocks are thermoplastic homopolymers or copolymers whose aromatic moieties are derived from vinylaromatic compounds which may be monocyclic or polycyclic. Examples of such vinyl aromatic compounds include styrene, α-methylstyrene, vinyltoluene, vinylxylene, ethylvinylxylene, vinylnaphthalene and mixtures thereof. The central block B is a conjugated diene hydrocarbon, such as 1,3-butadiene, 2,
It is an elastomeric polymer derived from 3-dimethylbutadiene, isoprene and 1,3-pentadiene and mixtures thereof. The molecular weight of each end block A and A'is preferably from about 2,000 to about 100,000.
While the molecular weight of midblock B is preferably in the range of about 25,000 to about 1,000,000.

Examples of stabilizers, UV absorbers, lubricants, pigments and fillers include stabilizers such as sterically hindered phenols and organic phosphites; salicylate-based, benzophenone-based, benzotriazole-based, organic nickel-based, UV absorbers such as oxalic acid diamide compounds or sterically hindered amine compounds; lubricants such as polyethylene wax and polypropylene wax; titanium oxide, zinc sulfide,
Pigments such as zinc oxide; mineral fillers such as glass fiber, asbestos, wollastonite, mica, talc, clay or charcoal, aluminum or zinc flakes and inorganic fillers such as brass, aluminum, zinc or stainless fibers. An organic filler represented by carbon fiber may be mentioned.

Hereinafter, the polyphenylene ether resin composition of the present invention will be specifically described with reference to Examples and Comparative Examples.

Example 1 2,6-Dimethylphenol / having an intrinsic viscosity of 0.53 (dl / g) measured at 25 ° C. using chloroform as a solvent.
2,3,6-trimethylphenol copolymer (2,3,6
6-trimethylphenol accounts for 5 mol%) 4
Rubber-modified polystyrene 5.4 having 3 parts by weight of polystyrene matrix having an intrinsic viscosity of 0.87 (dl / g) measured at 25 ° C. with chloroform as a solvent and having a gel portion content of 17% by weight. Parts by weight, polystyrene
Polybutadiene-polystyrene type elastomer block copolymer (weight ratio of styrene and butadiene is 70/3
0, a viscosity of 1 from a 20% solution in toluene at 25 ° C. measured with a Brookfield Model RTV viscometer
500 cps) 2 parts by weight, ethylene-propylene copolymer [reduced specific viscosity 2 (0.1 g / 100 ml) measured at 25 ° C. with decalin as a solvent] 1 part by weight, measured by GPC using THF solvent Number average molecular weight is 15
Brominated polystyrene having a bromine content of about 68% by weight and a softening point of 180 ° C. measured by a differential scanning calorimeter (manufactured by Fuero, Inc., trade name “Pyrocheck 68PB”) 14 Parts by weight, titanium oxide 7 parts by weight, 2,2'-methylene-bis (4-methyl-6-te)
rt-butylphenol) 0.6 part by weight and hydrogenated bisphenol A phosphite resin 0.4 part by weight are sufficiently melted and kneaded by a twin-screw extruder to knead them into pellets, and then the pellets are injected using an injection molding machine. Thickness 1.5mm, width 12.7mm, and length 127mm
A test piece of a certain degree was molded and a combustion test was performed.

The test method was carried out by holding the long axis of the test piece vertically, igniting the lower end of the test piece with a flame of a burner for 10 seconds, and measuring the burning time after removing the burner. The average value of the burning time obtained for the above was taken as the average burning time.

The physical properties other than the burning time are 6m in thickness for the heat distortion temperature.
A test piece measuring m, a width of 12.7 mm, and 127 mm was used, and a tensile strength was measured using a dumbbell piece having a thickness of about 3 mm. The results are shown in Table 1.

Example 2 The same composition as in Example 1 was carried out except that the amount of brominated polystyrene was changed to 7 parts by weight in Example 1. The results are shown in Table 1. Comparative Example 1 Example 1 was repeated with a composition excluding brominated polystyrene. The results are also shown in Table 1.

Comparative Example 2 The operation was repeated with the same composition as in Example 1 except that 14 parts by weight of brominated polystyrene in Example 1 was changed to 14 parts by weight of triphenyl phosphate. The results are also shown in Table 1.

Comparative Example 3 Of the 14 parts by weight of the brominated polystyrene used in Example 1, 7 parts by weight were replaced with 7 parts by weight of a phosphate obtained from isopropylphenol and phenol, and the operation was repeated with the same composition as in Example 1. It was The results are also shown in Table 1.

Example 3 In Example 1, 2,6-dimethylphenol / 2,
The intrinsic viscosity measured at 25 ° C in chloroform in place of 45 parts by weight of 3,6-trimethylphenol copolymer was 0.
55 (dl / g) poly (2,6-dimethyl-1,4-phenylene) ether 20 parts by weight was used, rubber modified polystyrene 54 parts by weight was replaced with 77 parts by weight, and antimony oxide 4 parts by weight was further added. Example 1 except for the addition
The procedure of Example 1 was repeated, using the same composition components as above but in the same amount. The results are shown in Table 2.

Example 4 Example 3 was repeated except that 14 parts by weight of brominated polystyrene was changed to 7 parts by weight, 4 parts by weight of triphenyl phosphate was added, and 4 parts by weight of antimony oxide was further reduced to 2 parts by weight. The operation was repeated with the same composition. The results are shown in Table 2.

Comparative Example 4 Example 3 was repeated with a composition in which 14 parts by weight of brominated polystyrene were changed to 14 parts by weight of triphenyl phosphate. The results are also shown in Table 2.

Comparative Example 5 The procedure of Example 4 was repeated, except that brominated polystyrene and antimony oxide were removed, and 4 parts by weight of triphenyl phosphate was changed to 11 parts by weight. The results are also shown in Table 2. Example 5 The procedure of Example 2 was repeated for the composition of Example 2 with 4 parts by weight of triphenyl phosphate and 2 parts by weight of antimony oxide added. The results are shown in Table 3.

Comparative Example 6 The procedure of Example 2 was repeated except that the brominated polystyrene was removed and 11 parts by weight of triphenyl phosphate was used. The results are also shown in Table 3.

Example 6 97 parts by weight of poly (2,6-dimethyl-1,4-phenylene) ether used in Example 3, 2 parts by weight of polystyrene-polybutadiene-polystyrene type elastomeric block copolymer used in Example 1, 1 part by weight of the ethylene-propylene copolymer used in Example 1, 6 parts by weight of brominated polystyrene used in Example 1, 3 parts by weight of triphenyl phosphate, 1.7 parts by weight of antimony oxide, 7 parts by weight of titanium oxide, 2,2'-methylene-bis (4-methyl-6-tert-butylphenol) 0.6
Parts by weight and 0.4 parts by weight of hydrogenated bisphenol A phosphite resin were melted and kneaded by the same operation as in Example 1, a test piece was molded, and various physical properties were measured. The results are shown in Table 4.

Comparative Example 7 In Example 6, except that brominated polystyrene and antimony oxide were excluded, 9 parts by weight of 3 parts by weight of triphenyl phosphate was used.
The operation was repeated with the same composition as in Example 6 except that the amount was changed to parts by weight. The results are also shown in Table 4.

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Claims (1)

[Claims] 1. (a) Polyphenylene ether or a mixture of polyphenylene ether and polystyrene resin 50.
To 99% by weight and (b) 1 to 50% by weight of brominated polystyrene having a bromine content of 67% by weight or more obtained by brominating polystyrene having a number average molecular weight of 50,000 or more. object.