JPH08231777A - Flame retardant for polyolefin having improved light exposure property - Google Patents

Abstract

PURPOSE: To provide a flame retardant giving more excellent light exposure properties than conventional. CONSTITUTION: This flame retardant for a polyolefin contains 100 pts.wt. of one or more than two kinds of bromine compound selected from bis(3,5-dibromo, 4-dibromopropyloxyphenyl) sulfone, 2,2-bis(3,5-dibromo, 4- dibromopropyloxyphenyl) propane, and tris(2,3-dibromopropyl) isocyanulate, 0.1-30 pts.wt. of benzotriazole-based ultraviolet absorber, 0.1-30 pts.wt. of hindered phenolic antioxidant and 0.1-30 pts.wt. of pentaerythritol diphosphite.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flame retardant for polyolefins having improved light resistance.

[0002]

Polyolefins are generally light, water resistant, and
Because of its excellent chemical resistance, electrical insulation and mechanical properties, and its easy molding process, it is widely used in building materials, electrical equipment materials, automobile materials, fibers, textile products and other applications. However, polyolefin has a drawback that it is easy to burn. For this reason, many methods for flame-retarding polyolefins have been proposed, but the most widely used method among these methods is to add a halogen compound or a halogen compound and antimony trioxide to the inside of the polyolefin. is there. Particularly, recently, bromine compounds have been widely used, but when these flame retardants are added, the light resistance of the polyolefin is deteriorated, and particularly when used outdoors, they are discolored or deteriorated, so that the use thereof is greatly limited.
As flame retardants for polyolefins, decabromodiphenyl ether, bis (pentabromophenoxy) ethane, decabromodiphenylethane, tetrabromobisphenol A, dodecachlorododecahydrodimethanodibenzocyclooctane, brominated polystyrene and the like are known. However, these flame retardants must be used in a large amount in order to make the polyolefin flame-retardant, and therefore, there is a drawback that the physical properties of the polyolefin are deteriorated and at the same time the light resistance is deteriorated. As a method for improving the light resistance of polyolefins, benzophenone-based, benzotriazole-based, benzoate-based, hindered amine-based light-resistant stabilizers and the like are generally used. However, a more effective light resistance stabilizer for a flame-retardant polyolefin containing a bromine compound has not been found.

[0003]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the problems in the prior art, and is particularly effective in flame retarding polyolefins.
-To improve the light resistance of a compound having a dibromopropyl group to a polyolefin.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a screw (3,5)
-Dibromo, 4-dibromopropyloxyphenyl) sulfone, 2,2-bis (3,5-dibromo, 4-dibromopropyloxyphenyl) proban, tris (2,3
1 selected from -dibromopropyl) isocyanurate
100 parts by weight of one or two or more bromine compounds, 0.1 to 30 parts by weight of benzotriazole type ultraviolet absorber, 0.1 to 30 parts by weight of hindered phenolic antioxidant and 0.1 to 0.1 parts of pentaerythritol diphosphite. A flame retardant for polyolefins having improved light resistance, which is characterized by containing 30 parts by weight.

The bromine compound used in the present invention is a 2,3-dibromopropyl group (--CH ₂ CHBrCH) in the molecule.
_{It has 2} Br) and is superior in flame retardancy to other flame retardants for polyolefins (bromine compounds),
The polyolefin can be made flame-retardant by adding an extremely small amount of / 5 to 1/10.

Examples of the benzotriazole type ultraviolet absorber used in the present invention include the following compounds. Two
(2-Hydroxy, 3-tert-butyl, 5-methylphenyl) 5-chlorobenzotriazole, 2 (2-hydroxy, 3,5-ditert-butylphenyl) 5-chlorobenzotriazole, 2 (2-hydroxy, 3,5-di te
rt-Amylphenyl) benzotriazole, 2 (2-hydroxy, 5-tert-octylphenyl) benzotriazole, 2 (2-hydroxy, 5-methylphenyl) benzotriazole, 2 [2-hydroxy, 3,5-bis ( α, α-Dimethylbenzyl) phenyl] benzotriazole, 2 (2-hydroxy, 3,5-ditert-butylphenyl) benzotriazole, 2 [2-hydroxy,
3 (3,4,5,6-tetrahydrophthalimidomethyl) 5-methylphenyl] benzotriazole, 2 (2
-Hydroxy, 3-dodecyl, 5-methylphenyl) benzotriazole and the like. The content of the benzotriazole-based ultraviolet absorber is 0.1 with respect to 100 parts by weight of the bromine compound.
~ 30 parts by weight. If the content is less than this, the light resistance of the polyolefin is not sufficiently improved, and if it is more than this, no remarkable improvement in the effect is recognized and the flame retardant performance is deteriorated.

Examples of the hindered phenolic antioxidant used in the present invention include the following compounds. Pentaerythrityl tetrakis [3 (3,5-ditert-butyl, 4-hydroxyphenyl) propionate], octadecyl 3 (3,5-ditert-butyl, 4-hydroxyphenyl) propionate, triethylene glycol bis [3 ( 3tert-butyl, 5-methyl, 4-hydroxyphenyl) propionate], 1,6-hexanediol bis [3 (3,5-ditertbutyl, 4-hydroxyphenyl) propionate], 2,4-bis (n-octylthio) ) -6- (4-Hydroxy, 3,5-ditertbutylanilino) 1,3,5-triazine, 2,2-thiodiethylenebis [3 (3,5-ditertbutyl, 4-hydroxyphenyl) propionate] , Diethyl, 3,5-di
tert-butyl, 4-hydroxybenzylphosphonate,
1,3,5-trimethyl, 2,4,6-tris (3,5
-Ditertbutyl, 4-hydroxybenzyl) benzene,
Tris (3,5-ditertbutyl, 4-hydroxybenzyl) isocyanurate, 2,4-bis [(octylthio) methyl-o-cresol. The content of the hindered phenolic antioxidant is 0.1 to 30 parts by weight based on 100 parts by weight of the bromine compound. If the content is less than this, the light resistance of the polyolefin is not sufficiently improved, and if it is more than this, no remarkable improvement in the effect is recognized and the flame retardant performance is deteriorated.

The pentaerythritol diphosphite used in the present invention includes the following compounds. Bis (2,6-ditert-butyl, 4-methylphenyl) pentaerythritol diphosphite, bis (2,4-di)
tert-Butylphenyl) pentaerythritol diphosphite, bis (2,6-ditert-butyl, 4-ethylphenyl) pentaerythritol diphosphite, bis (2,6-ditert-butyl, 4-isopropylphenyl) penta Erythritol diphosphite, bis (2,
4,6-Tritert-butylphenyl) pentaerythritol diphosphite, dinonylphenyl pentaerythritol diphosphite, dilauryl pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, 2,4-ditertbutylphenyl stearyl Pentaerythritol diphosphite. The content of pentaerythritol diphosphite is 10
It is 0.1 to 30 parts by weight with respect to 0 parts by weight. If the content is less than this, the light resistance of the polyolefin is not sufficiently improved, and if it is more than this, no remarkable improvement in the effect is recognized and the flame retardant performance is deteriorated.

The flame retardant for polyolefin of the present invention may contain a bromine compound, a benzotriazole type ultraviolet absorber, a hindered phenol type antioxidant and pentaerythritol diphosphite in separate containers, but as a mixture. It is convenient to use if you leave it. The mixture of flame retardants for polyolefin is 100 parts by weight of bromine compound, 0.1 to 30 parts by weight of benzotriazole-based ultraviolet absorber, 0.1 to 30 parts by weight of hindered phenolic antioxidant, and 0.1 parts of pentaerythritol diphosphite. It can be produced by adding ~ 30 parts by weight and mixing. After melting the bromine compound, a benzotriazole-based ultraviolet absorber, a hindered phenol-based antioxidant and pentaerythritol diphosphite may be dispersed or dissolved in the melt.

The polyolefin flame retardant of the present invention includes a flame retardant aid (for example, antimony trioxide, antimony pentoxide,
Sodium antimonate, zinc borate, tin oxide, zinc stannate, molybdenum oxide, etc.) are preferably added. Addition amount of flame retardant aid is 1 with respect to 100 parts by weight of bromine compound.
-80 parts by weight, preferably 3-60 parts by weight. Also,
The flame retardant for polyolefin of the present invention includes a colorant, a smoke reducer, an antistatic agent, a drip-free agent, an antifogging agent, a lubricant, a dispersant, a nucleating agent, a metal deactivator, an antibacterial agent, and a coupling agent. Inorganic fillers, impact modifiers, other flame retardants, ultraviolet absorbers, light stabilizers, antioxidants, heat stabilizers, and other additives may be used together within a range that does not impair the performance.

In the present invention, as the polyolefin, ethylene, propylene, butene-1, pentene-
1, polymers such as hexene-1, octene-1, and 4-methylpentene-1, ethylene-propylene-diene terpolymers, copolymers of α-olefins with vinyl acetate or acrylic ester, or these Two or more types of copolymers may be mentioned. Further, these polyolefins are synthetic rubbers (for example, polybutadiene, polychloroprene, styrene-butadiene rubber, acrylonitrile-butadiene rubber) and other thermoplastic resins (for example, polystyrene, ABS).
A resin, polyvinyl chloride, polyvinylidene chloride) or the like can be mixed and used.

The blending amount of the flame retardant for polyolefin of the present invention is 0.1 to 30% by weight with respect to the polyolefin. If the blending amount is less than 0.1% by weight, the effect of the flame retardant is insufficient, and if it exceeds 30% by weight, the physical properties, particularly the strength, deteriorate. The polyolefin containing the flame retardant for polyolefin of the present invention can be processed into various molded articles by a general molding method. As the molded product, for example, a plate,
Examples include tubes, pipes, films, tapes, ribbons and fibers. These can be used for electric equipment materials, automobile parts, interior goods, construction materials, clothing goods, sundries, and the like.

[0013]

[Examples] "Parts" in the following formulation examples mean "parts by weight". In addition, the abbreviated compounds are as follows. * Bromine compound Bromine compound (1): bis (3,5-dibromo, 4-dibromopropyloxyphenyl) sulfone, bromine compound (2): 2,2-bis (3,5-dibromo,
4-dibromopropyloxyphenyl) proban, bromine compound (3): tris (2,3-dibromopropyl) isocyanurate, * benzotriazole-based UV absorber UV absorber (1): 2 (2-hydroxy, 3-tert. Butyl, 5-methylphenyl) 5-chlorobenzotriazole, UV absorber (2): 2 (2-hydroxy, 3,5-di
tert-butylphenyl) 5-chlorobenzotriazole,

* Benzophenone type UV absorber (used in Comparative Example) UV absorber (A): 2-hydroxy, 4-octyloxybenzophenone, UV absorber (B): 2-hydroxy, 4-methoxybenzophenone, * Hinder Dephenolic antioxidant Antioxidant (1): Pentaerythrityl tetrakis [3
(3,5-ditert-butyl, 4-hydroxyphenyl)
Propionate], antioxidant (2): octadecyl 3 (3,5-ditert-
Butyl, 4-hydroxyphenyl) propionate * Pentaerythritol diphosphite [hereinafter, PED
Abbreviated as P] PEDP (1): bis (2,6-ditert-butyl, 4-
Methylphenyl) pentaerythritol diphosphite, PEDP (2): bis (2,4-ditert-butylphenyl) pentaerythritol diphosphite,

Formulation Example 1 To 30 parts of a bromine compound (1), 1 part of an ultraviolet absorber (1), 1 part of an antioxidant (1), 1 part of PEDP (1) and 15 parts of antimony trioxide were added and mixed. A flame retardant for polyolefin was manufactured. Formulation Example 2 To 30 parts of a bromine compound (1), 3 parts of an ultraviolet absorber (1), 3 parts of an antioxidant (1), 2 parts of PEDP (1) and 15 parts of antimony trioxide were added and mixed to obtain a mixture for polyolefin. A combustor was produced. Formulation Example 3 To 30 parts of a bromine compound (1), 5 parts of an ultraviolet absorber (1), 5 parts of an antioxidant (1), 3 parts of PEDP (1) and 15 parts of antimony trioxide were added and mixed to obtain a mixture for polyolefin. A combustor was produced. Formulation Example 4 To 30 parts of a bromine compound (1), 1 part of an ultraviolet absorber (2), 1 part of an antioxidant (2), 1 part of PEDP (2) and 15 parts of antimony trioxide were added and mixed to obtain a mixture for polyolefin. A combustor was produced.

Formulation Example 5 To 30 parts of a bromine compound (1), 3 parts of an ultraviolet absorber (2), 3 parts of an antioxidant (2), 2 parts of PEDP (2) and 15 parts of antimony trioxide were added and mixed. A flame retardant for polyolefin was manufactured. Formulation Example 6 To 30 parts of a bromine compound (1), 3 parts of an ultraviolet absorber (1), 3 parts of an antioxidant (2), 2 parts of PEDP (1) and 15 parts of antimony trioxide were added and mixed to obtain a mixture for polyolefin. A combustor was produced. Formulation Example 7 To 30 parts of a bromine compound (2), 1 part of an ultraviolet absorber (1), 1 part of an antioxidant (1), 1 part of PEDP (1) and 15 parts of antimony trioxide were added and mixed to obtain a mixture for polyolefin. A combustor was produced. Formulation Example 8 To 30 parts of a bromine compound (2), 3 parts of an ultraviolet absorber (1), 3 parts of an antioxidant (2), 2 parts of PEDP (2) and 15 parts of antimony trioxide were added and mixed to obtain a mixture for polyolefin. A combustor was produced.

Formulation Example 9 To 30 parts of a bromine compound (3), 1 part of an ultraviolet absorber (1), 1 part of an antioxidant (1), 1 part of PEDP (1) and 15 parts of antimony trioxide were added and mixed. A flame retardant for polyolefin was manufactured. Formulation Example 10 To 30 parts of a bromine compound (3), 3 parts of an ultraviolet absorber (1), 3 parts of an antioxidant (2), 2 parts of PEDP (2) and 15 parts of antimony trioxide were added and mixed to obtain a mixture for polyolefin. A combustor was produced. Formulation Example 11 100 parts of the bromine compound (1) to 3 parts of the ultraviolet absorber (1),
3 parts of antioxidant (1), 2 parts of PEDP (1) and 50 parts of antimony trioxide were added and mixed to produce a flame retardant for polyolefin. Formulation Example 12 100 parts of bromine compound (1) to 5 parts of ultraviolet absorber (1),
5 parts of antioxidant (1), 3 parts of PEDP (1) and 50 parts of antimony trioxide were added and mixed to produce a flame retardant for polyolefin.

Formulation Example 13 100 parts of bromine compound (1) to 3 parts of ultraviolet absorber (2),
3 parts of antioxidant (2), 2 parts of PEDP (2) and 50 parts of antimony trioxide were added and mixed to produce a flame retardant for polyolefin. Formulation Example 14 100 parts of a bromine compound (2) to 3 parts of an ultraviolet absorber (1),
3 parts of antioxidant (1), 2 parts of PEDP (1) and 50 parts of antimony trioxide were added and mixed to produce a flame retardant for polyolefin. Formulation Example 15 100 parts of a bromine compound (2) to 3 parts of an ultraviolet absorber (1),
3 parts of antioxidant (2), 2 parts of PEDP (2) and 50 parts of antimony trioxide were added and mixed to produce a flame retardant for polyolefin. Formulation Example 16 150 parts of bromine compound (1), 150 parts of bromine compound (2)
Parts, UV absorber (1) 5 parts, UV absorber (2) 5
Parts, antioxidant (1) 5 parts, antioxidant (2) 5 parts, P
A flame retardant for polyolefin was manufactured by mixing 5 parts of EDP (1), 5 parts of PEDP (2) and 150 parts of antimony trioxide.

Formulation Example 17 10 parts of bromine compound (1), 10 parts of bromine compound (2), 10 parts of bromine compound (3), 2 parts of ultraviolet absorber (1), 1 part of ultraviolet absorber (2), antioxidant Agent (1) 2 parts, antioxidant (2) 1 part, PEDP (1) 1 part, PEDP (2) 1
Parts and 15 parts of antimony trioxide were mixed to produce a flame retardant for polyolefin. Formulation Example 18 To 30 parts of a bromine compound (1), 1 part of an ultraviolet absorber (1), 1 part of an antioxidant (1), 1 part of PEDP (2) and 15 parts of antimony trioxide were added and mixed to obtain a mixture for polyolefin. A combustor was produced. Formulation Example 19 To 30 parts of a bromine compound (1), 3 parts of an ultraviolet absorber (2), 3 parts of an antioxidant (2), 2 parts of PEDP (1) and 15 parts of antimony trioxide were added and mixed to obtain a mixture for polyolefin. A combustor was produced.

Comparative Preparation Example 1 30 parts of a bromine compound (3), 1 part of PEDP (1), 1 part of bis (2,2,6,6-tetramethyl, 4-piperidyl) sebacate (a hindered amine light stabilizer) and 15 parts of antimony trioxide was added and mixed to produce a flame retardant. Comparative formulation example 2 To 30 parts of a bromine compound (1), 1 part of an ultraviolet absorber (1), 1 part of an antioxidant (1), and 15 parts of antimony trioxide were added and mixed to prepare a flame retardant. Comparative Formulation Example 3 30 parts of bromine compound (1) to 1 part of UV absorber (1), P
Add 1 part EDP (1) and 15 parts antimony trioxide,
Mixed to produce a flame retardant. Comparative formulation example 4 A flame retardant was produced by adding 1 part of tricresyl phosphite [(phosphite (1)]] to the formulation of comparative formulation example 2.

Comparative Formulation Example 5 A flame retardant was produced by using 1 part of tris (2,4-ditertbutylphenyl) phosphite [(phosphite (2)] in place of the phosphite (1) of Comparative Formulation Example 4. Comparative Formulation Example 6 To 30 parts of a bromine compound (1), 1 part of an ultraviolet absorber (A), 1 part of an antioxidant (1), 1 part of PEDP (1) and 15 parts of antimony trioxide were added and mixed. Comparative Formulation Example 7 To 30 parts of a bromine compound (1), 1 part of an ultraviolet absorber (B), 1 part of an antioxidant (2), 1 part of PEDP (2) and 15 parts of antimony trioxide were added. A flame-retardant was manufactured by mixing, Comparative Preparation Example 8 2,4-Di in place of the ultraviolet absorbent (A) of Comparative Preparation Example 6
A flame retardant was produced using 1 part of tert-butylphenyl, 3,5-ditert-butyl, 4-hydroxybenzoate (hydroxybenzoate-based light fastness stabilizer).

Comparative Preparation Example 9 30 parts of bromine compound (1), 1 part of ultraviolet absorber (2), 1 part of antioxidant (2), bis (2,2,6,6-tetramethyl, 4-piperidyl) 1 part of sebacate (hindered amine light stabilizer) and 15 parts of antimony trioxide were added and mixed to prepare a flame retardant. Comparative Formulation Example 10 To 30 parts of a bromine compound (2), 1 part of an ultraviolet absorber (1), 1 part of an antioxidant (1), 1 part of a phosphite (2) and 15 parts of antimony trioxide were added, and mixing was difficult. A combustor was produced. Comparative Formulation Example 11 To 30 parts of a bromine compound (3), 1 part of an ultraviolet absorber (2), 1 part of an antioxidant (2), 1 part of a phosphite (1) and 15 parts of antimony trioxide were added, and mixing was difficult. A combustor was produced.

Comparative Preparation Example 12 To 30 parts of a bromine compound (1), 1 part of an ultraviolet absorber (A), 1 part of an antioxidant (2), 1 part of PEDP (2) and 15 parts of antimony trioxide were added and mixed. To produce a flame retardant. Comparative Formulation Example 13 To 30 parts of a bromine compound (2), 1 part of an ultraviolet absorber (B), 1 part of an antioxidant (1), 1 part of PEDP (1) and 15 parts of antimony trioxide were added and mixed to obtain a flame retardant. Was manufactured. Comparative Formulation Example 14 To 30 parts of a bromine compound (3), 1 part of an ultraviolet absorber (A), 1 part of an antioxidant (1), 1 part of PEDP (1) and 15 parts of antimony trioxide were added and mixed to obtain a flame retardant. Was manufactured.

Experimental Example Each additive was added to commercially available polypropylene or propylene-ethylene copolymer, and the mixture was mixed with a mixing roll at 150.
Knead at ~ 160 ° C for about 15 minutes, then at a temperature of 200 ° C,
Press at a pressure of 100 kg / cm ² for 5 minutes to obtain a thickness of 1.
A 5 mm plate was molded. The following evaluation was performed using this molded product. As the commercially available polypropylene, polypropylene homopolymer (Noble W101, manufactured by Sumitomo Chemical Co., Ltd.) and propylene-ethylene copolymer (ethylene content 2.5%) were used.

Evaluation of light resistance: A plate having a thickness of 1.5 mm was cut into a size of 6.5 × 5 cm, irradiated with a fade meter at 63 ° C. for 120 hours, and a color difference meter (ND, manufactured by Nippon Denshoku Industries Co., Ltd.). -101DP type), L, a, and b values were measured for the samples before and after irradiation, and the color difference ΔE was determined by the following formula. In the formula, L is the lightness, a is the degree of red and green,
b indicates the degree of yellow and blue.

(Equation 1)

Evaluation of flame retardant performance: Using a sample having a thickness of 1.5 mm, a combustion test by a vertical method of UL-94 (underwriters Laboratories Inc) and JIS K7201 were conducted.
The oxygen index was measured. Table 1 shows the evaluation results when the flame retardant of the present invention was added to polypropylene homopolymer, and Table 2 shows comparative examples. Table 3 shows the evaluation results when the flame retardant of the present invention was added to the polypropylene copolymer, and Table 4 shows comparative examples. The numerical values in the table indicate the addition amount (parts by weight) with respect to 100 parts by weight of the polyolefin, and the numbers in parentheses indicate the compound numbers.

[0027]

[Table 1] Note 1: The ingredients of No. 1-17 are the same as those of Formulation Examples 1-17. Note 2: No. 16 is 1.5 parts for bromine compounds (1) and (2), for a total of 3 parts. Note 3: No. 17 is 1 part for each of bromine compounds (1), (2), and (3), for a total of 3 parts.

[0028]

[Table 2] Note 1: The components of No. 6-14 are the same as those of Comparative Preparation Examples 1-9. Note 2: Nos. 6, 9, 10, 13 and 14 contain other ingredients. Note 3: No. 17 is 1 part for each of bromine compounds (1), (2), and (3), for a total of 3 parts.

[0029]

[Table 3] Note 1: The components of No. 23 and 24 are the same as those of Preparation Examples 16 and 17. Note 2: No. 23 is 3 parts in total for 1.5 parts each of bromine compound (1) and (2). Note 3: No. 24 is 1 part for each of bromine compounds (1), (2) and (3), for a total of 3 parts.

[0030]

[Table 4] Note 1: The components of NO21 are the same as in Comparative Preparation Example 4. Note 2: No. 22 to 26 have the same components as Comparative Preparation Examples 10 to 14. Note 3: Nos. 21 to 23 include other components.

[0031]

INDUSTRIAL APPLICABILITY The flame retardant for polyolefins of the present invention can impart excellent flame retardancy and light resistance to polyolefins at the same time. The polyolefin to which the flame retardant of the present invention is added has excellent light resistance, so that the restrictions conventionally imposed on the application are greatly improved.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C08K 5/45 C08K 5/45 5/524 KFM 5/524 KFM C09K 3/00 104 C09K 3/00 104C 21/08 21/08 21/10 21/10 21/12 21/12

Claims (4)

[Claims] 1. Bis (3,5-dibromo, 4-dibromopropyloxyphenyl) sulfone, 2,2-bis (3,5-dibromo, 4-dibromopropyloxyphenyl) propane, tris (2,3-dibromo) Propyl)
100 parts by weight of one or more bromine compounds selected from isocyanurate, 0.1 to 30 parts by weight of benzotriazole-based ultraviolet absorber, 0.1 to 30 parts by weight of hindered phenolic antioxidant, and pentaerythritol A flame retardant for polyolefin having improved light resistance, which comprises 0.1 to 30 parts by weight of diphosphite. 2. The benzotriazole-based ultraviolet absorber is 2
(2-hydroxy, 3-tert-butyl, 5-methylphenyl) 5-chlorobenzotriazole, 2 (2-hydroxy, 3,5-ditert-butylphenyl) 5-chlorobenzotriazole, or a mixture thereof. Item 1. A flame retardant agent for polyolefin according to Item 1. 3. A hindered phenolic antioxidant is pentaerythrityl tetrakis [3 (3,5-ditert-butyl, 4-hydroxyphenyl) propionate], octadecyl 3 (3,5-ditert-butyl, 4). The flame retardant for polyolefins according to claim 1, which is -hydroxyphenyl) propionate or a mixture thereof. 4. Pentaerythritol diphosphite is bis (2,6-ditert-butyl, 4-methylphenyl).
Pentaerythritol diphosphite, bis (2,4-
The flame retardant for polyolefin according to claim 1, which is di-tert-butylphenyl) pentaerythritol diphosphite or a mixture thereof.