JP2001011322A - Flame retardant thermoplastic resin composition without being adversely affected by iron oxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition capable of preventing the occurrence of defective molded products caused by a reaction of a decomposition product of a bromine-based flame retardant with iron oxide sticking to an apparatus for molding and processing by including a thermoplastic resin, a flame retardant satisfying specific standards and a chelating agent in specified amounts. SOLUTION: This composition comprises (A) a thermoplastic resin, (B) a bromine-containing flame retardant having <=0.1 wt.% heating loss of the flame retardant alone at 130 deg.C×2 h and lower 1% and 5% weight-loss temperatures of a mixture of the flame retardant with iron oxide in 20:1 weight ratio of the flame retardant to the iron oxide measured by a differential thermal analysis (at 10 deg.C/min heat-up rate) in a gas stream of air than the 1% and 5% weight- loss temperatures of the flame retardant alone under the same conditions measured by the differential thermal analysis by at least 30 deg.C in an amount of >=2 pts.wt. based on 100 pts.wt. of the component A and (C) a chelating agent in an amount of 0.001-2 pts.wt. based on 100 pts.wt. of the component A. Tetrabromocyclooctane, etc., are preferably used as the component B. A phosphorous acid triester, etc., are preferably used as the component C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a flame-retardant thermoplastic resin composition,
In particular, it is possible to prevent the generation of defective molded products due to the reaction of the decomposition products of the added brominated flame retardant with iron oxide (Fe ₂ O ₃ , Fe ₃ O _4, etc.) adhering to the molding / processing equipment. And a flame-retardant thermoplastic resin composition.

[0002]

BACKGROUND OF THE INVENTION It is well-known that plastic molded articles, including electric and electronic parts, which require flame retardancy, are made flame-retardant with a flame retardant and a flame retardant aid such as antimony trioxide. . The thermoplastic resin composition containing a bromine-based flame retardant used for this purpose suppresses the generation of decomposition products such as bromine radicals and hydrogen bromide generated by the thermal decomposition of the flame retardant at a temperature not lower than the melting temperature of the resin, or suppresses it. It generally contains catching heat stabilizers, thereby preventing resin coloration and equipment corrosion.

[0003] Apart from the problem caused by the thermal decomposition products of the flame retardant at temperatures above the melting temperature of the resin, depending on the flame retardant included if the extruder or other molding machine has been used for a long time, An unexpected molding defect may occur. The cause was not clarified so far, and when pursued, iron oxide was gradually deposited inside the device due to burns and rust, which came into contact with the brominated flame retardant and produced iron bromide. I understand. If the formed iron bromide remains on the mold surface, the molded product surface will be depressed and sink marks will appear, resulting in molding failure.If the iron bromide is incorporated into the molded product, it will absorb moisture during handling or during use after molding. Swelling,
This may cause defects such as voids. The solution of this problem is the subject of the present invention.

[0004]

The problems associated with the iron bromide formed by the reaction of the iron oxide and the flame retardant deposited inside the molding apparatus described above are not specific to all of the bromine-containing flame retardants, but to a specific group of flame retardants. Specifically or unacceptably practically. Therefore, a standard that can identify such a group is needed.

In the present invention, the target brominated flame retardant (a) is specified using the following criteria.

(1) In the heat loss test of the flame retardant alone at 130 ° C. × 2 hours, the heat loss is 0.1% by weight or less.

(2) Weight ratio of the flame retardant to iron oxide: 2
When the mixture of 0: 1 is measured by differential thermal analysis in a stream of air at a heating rate of 10 ° C./min, the 1% and 5% weight loss temperatures measured by differential thermal analysis under the same conditions using the flame retardant alone. Each corresponding weight loss temperature is at least 3
0 ° C lower.

It is an object of the present invention to provide a thermoplastic resin, 2 parts by weight or more of a flame retardant satisfying the above criteria (a), and (b) a chelating agent of 0.001 per 100 parts by weight of the thermoplastic resin.
The problem is solved by providing a flame-retardant thermoplastic resin composition containing 〜2 parts by weight.

[0009]

Specific examples of thermoplastic resins include, but are not limited to, polyethylene, polypropylene, polystyrene, polymethyl methacrylate, HI-PS resin, ABS resin, ethylene-vinyl acetate resin (EVA), and polymer blends thereof. Without limitation, all other flammable thermoplastics can be used in the present invention.

Examples of bromine-containing flame retardants meeting the aforementioned criteria include tetrabromocyclooctane, hexabromocyclododecane (abbreviation HBCD), tribromophenyl-dibromopropyl ether, tribromophenyl-1,2.
-Dibromo-2-methylpropyl ether (abbreviation TBP)
-MDBPE), tetrabromobisphenol A-bisdibromopropyl ether (abbreviation: TBBA-BDBP)
E), tetrabromobisphenol S-bisdibromopropyl ether (abbreviation TBBS-BDBPE), trisdibromopropyl isocyanurate (abbreviation TDBPI)
C), but not limited thereto.

On the other hand, for example, tristribromoneopentyl phosphate (abbreviation TTBNPP) and tristribromophenoxytriazine (abbreviation TTBPT)
A) does not satisfy the criterion (2) described above. Table 1 below shows 1% and 5% of the flame retardant alone and its iron oxide mixture.
The measured value of% weight loss temperature is shown.

[0012]

[Table 1]

The amount of flame retardant added depends on the grade of flame retardancy to be obtained. For example, UL-9 for HI-PS resin
In order to obtain a grade of V-2 in resin No. 4, resin 10
2 to 10 parts by weight per 0 parts by weight is added. If higher flame retardancy is desired, it is necessary to increase the amount of addition, but even if it is added excessively, the effect corresponding to it will not be obtained, and the mechanical strength of the plate-out or molded product will decrease unacceptably. Thus, generally up to about 20% by weight of the thermoplastic will be the limit.

In the present invention, a chelating agent is added to the resin composition in order to prevent iron bromide generated by the reaction between the above flame retardant and iron oxide from adversely affecting the quality of the molded article.

Examples of chelating agents that can be used for this purpose include, but are not limited to:

Phosphorous triesters: aliphatic phosphites such as trioctyl phosphite, tridecyl phosphite and tridodecyl phosphite; triphenyl phosphite, tris nonyl phenyl phosphite, tris-t-butyl phenyl phosphite and the like Aromatic phosphites; mixed phosphites of aliphatic and aromatic such as diphenyloctyl phosphite and diphenylisodecyl phosphite; bisphenol A-bisdialkyl phosphite, dialkylpentaerythritol diphosphite, 2,2'-methylenebis- Di-t-butylphenyloctyl phosphite, 10-decyloxy-9,10-
Other phosphites such as dihydro-9-oxa-10-phosphaphenanthrene.

Phosphoric acid mono- or diesters or metal salts thereof: having 1 to 2 carbon atoms as the alcohol moiety of the ester
Aliphatic alcohols, phenols which may have a substituent such as an alkyl group, mono-phosphates of phosphoric acid having ethylene oxide adducts of these alcohols or phenols
Or diesters, and L of these phosphate esters
i, Na, K, Mg, Cu, Ca, Sr, Ba, Zn,
Metal salts such as Al.

Condensed phosphates: sodium pyrophosphate, potassium pyrophosphate, sodium acid pyrophosphate, sodium acid metaphosphate, sodium tripolyphosphate, sodium hexametaphosphate and the like.

Diphosphonic acid or its metal salt: hydroxyethylidene-1,1-diphosphonic acid, its alkali metal salt and alkaline earth metal salt.

Triazole chelate compound: 3- (N
-Salicyloyl) amino-1,2,4-triazole,
4-salicylideneimino-3,5-diphenyl-1,
2,4-triazole, 3,5-bis (4-amino-
1,2,4-triazole) and the like.

Hydrazine chelate compound: N, N'-
Bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) proonyl] hydrazine, decanedicarboxylic acid disalicyloyl hydrazide, decanedicarboxylic acid di-
N'-butylsalicyloyl hydrazide and the like.

Polycarboxylic acids or metal salts thereof: succinic acid, fumaric acid, citric acid, tartaric acid, malic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, alkali metal salts and alkaline earth metal salts thereof.

The addition amount of the chelating agent is 0.001 to 2% by weight of the thermoplastic resin. Excessive addition of a chelating agent should be avoided because it causes plate-out and a decrease in the mechanical strength of the molded article.

The flame-retardant thermoplastic resin composition of the present invention may contain a conventional flame-retardant aid such as antimony trioxide, a heat stabilizer, an ultraviolet absorber, an antioxidant, a lubricant, a coloring agent, a filler and the like. Additives may be included.

As a method of mixing the flame retardant and the chelating agent into the thermoplastic resin, the two are directly mixed in advance, or the flame retardant and the chelating agent are dissolved, dispersed or emulsified in water or an organic solvent, and then the medium is mixed. By removing the mixture, a uniform mixture is formed, and the mixture is kneaded with the resin using an extruder, a Banbury mixer, a hot roll, or the like, together with other components.

[0026]

[Example] Example 1 Raw material parts by weight ───────────────────── ──────── HI-PS resin (Nippon Steel Chemical Co., Ltd.) 100) Estyrene H-65) TBBA-BDBPE 7 Antimony trioxide 2 Irganox 1010 0.1 Trisnonylphenyl phosphite (TNP) 0.005

The above materials were mixed with a Henschel mixer and kneaded with a twin screw extruder set at 200 ° C. to obtain resin pellets for testing.

Example 2 In place of TNP of Example 1, 2,2'-methylenebis (4,6-di-t-butylphenyl) octyl phosphite (mp. 148 ° C.) (Adeka Stab manufactured by Asahi Denka Kogyo KK) HP-10) Example 1 except that 0.1 part by weight was used.
Same as

Example 3 In place of TNP of Example 1, 3- (N-salicyloyl) amino-1,2,4-triazole (mp. 210 ° C.)
(Adeka Stub CAD-1M manufactured by Asahi Denka Kogyo Co., Ltd.)
Same as Example 1 except that 5 parts by weight was used.

EXAMPLE 4 10 g of an aqueous methanol (1: 1) solution containing 50% by weight of a mono- and di-mixed phosphate ester sodium salt (CH-P1) of an ethylene oxide 8 mol adduct of distyrenated phenol was mixed with 1 kg of TBBA-BDBPE. , And mixed with a speed mixer, and then dried with a blast drier at 60 ° C.
1% of 0.5% CH-P1 added TBBA-BDBPE was obtained. This was replaced with 7 parts by weight (0.03 as CH-P1) in place of TBBA-BDBPE and TNP of Example 1.
5 parts by weight) to obtain resin pellets for test in the same manner as in Example 1.

Example 5 Hydroxyethylidene-1,1-diphosphonic acid (CH-
10 g of a 10% aqueous solution of P2) is sprayed onto 1 kg of TBBA-BDBPE powder with stirring with a Henschel mixer, mixed for 3 minutes, dried with a blast drier at 60 ° C, and volatilized after heating at 130 ° C for 2 hours. A 0.1% CH-P2 added TBBA-BDBPE having a content of 0.1% was obtained.

This was replaced with TBBA-BDBP of Example 1.
7 parts by weight (0.007 parts by weight as CH-P2) were added instead of E and TNP, and a resin pellet for testing was obtained in the same manner as in Example 1.

Example 6 1 kg of TBBA-BDBPE was dispersed in 1 L of isopropyl alcohol using a homomixer, and 100 g of a 10% aqueous solution of tetrasodium ethylenediaminetetraacetate was added thereto.
Was gradually added dropwise, and after completion of the addition, the mixture was filtered through 5B filter paper and dried to obtain 1% EDTA-added TBBA-BDBPE.

This was replaced with TBBA-BDBP of Example 1.
7 parts by weight instead of E and TNP (0.
07 parts by weight) to obtain resin pellets for testing in the same manner as in Example 1.

Comparative Example 1 Test resin pellets were prepared in Example 1 without adding TNP.

Comparative Example 2 The same amount of TT was used instead of TBBA-BDBPE of Comparative Example 1.
BNPP was used as a flame retardant to produce resin pellets for testing.

Comparative Example 3 The same as Example 1 except that 0.5 parts by weight of hydrotalcite (DHT-4A manufactured by Kyowa Chemical Industry Co., Ltd.) was used instead of TNP of Example 1.

[0038]

[Test method] Flame retardancy test: Test resin pellets at 200 ° C
The test piece was molded into a UL-94 flame-retardant test piece (1/8 inch thick) using an injection molding machine set as described above, and tested by the UL-94 flame-retardant test method.

Heating color stability test: 20 resin pellets
0 kg / cm ² , 230 ° C. × 5 minutes and 230 ° C. × 20
The test pieces were press-formed into two types of test specimens each having a thickness of 1/16 inch under the conditions of minutes, and each was cooled by a cold press for 5 minutes.
The difference (ΔYI) between the YI values of the two was measured with a color difference meter, and the heat-resistant coloring stability in a state not in contact with iron oxide was tested.

Iron oxide resistance temporal stability test: resin pellet 1
00 parts and ₂ parts of Fe ₂ O ₃ were mixed with a Henschel mixer and press-molded for 20 minutes under the same method and temperature conditions as in the heat-resistant coloring stability test to prepare test pieces. The obtained test piece was divided into 2 minutes, one was stored in a silica gel desiccator at room temperature, and the other was stored in a constant temperature and humidity oven at 80% RH and a temperature of 40 ° C. for 5 days. The surface condition was observed and evaluated according to the following criteria. did. 〇: There was no difference between the two in the surface state immediately after molding. Δ: No change was observed in the sample stored in the desiccator, and blistering occurred in the sample stored in the constant temperature and humidity oven. ×: Voids or sink marks were generated on the surface immediately after molding, and those stored in a constant-temperature and constant-humidity oven blistered.

[0041]

[Results] Table 2 shows the obtained results.

[0042]

[Table 2]

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Claims (3)

[Claims] 1. A thermoplastic resin and 100 parts by weight of a thermoplastic resin, wherein (a) the weight loss of the flame retardant alone at 130 ° C. for 2 hours is 0.1% by weight or less, and the flame retardant and iron oxide Weight ratio of 2
Differential thermal analysis of a 0: 1 mixture in an air stream (heating rate 1
1% and 5% weight loss temperature measured by
At least 30 ° C. lower than the 1% and 5% weight loss temperatures measured by differential thermal analysis of the flame retardant alone under the same conditions,
A flame-retardant thermoplastic resin composition in which a molded article containing 2 parts by weight or more of a bromine-containing flame retardant and (b) 0.001 to 2 parts by weight of a chelating agent is not adversely affected by iron oxide. 2. The brominated flame retardant (a) is selected from tetrabromocyclooctane, hexabromocyclododecane, tribromophenyl-dibromopropyl ether, tribromophenyl-1,2-dibromo-2-methylpropyl ether, 2. The composition of claim 1 wherein the composition is selected from bisphenol A-bisdibromopropyl ether, tetrabromobisphenol S-bisdibromopropyl ether and trisdibromopropyl isocyanurate. 3. The chelating agent (b) is a phosphite triester, a phosphoric acid mono- or diester or a metal salt thereof, a condensed phosphate, a diphosphonic acid or a metal salt thereof,
3. The composition according to claim 1, wherein the composition is selected from a triazole-based chelate compound, a hydrazine-based chelate compound, and a polyvalent carboxylic acid or a metal salt thereof.