JP2005240018A - Non-halogen flame-retardant resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-halogen flame-retardant resin composition which does not emit halogen gases at the time of combustion, shows sufficiently high flame retardancy by a smaller amount of a metal hydroxide than before and is excellent in environmental safety. <P>SOLUTION: This non-halogen flame-retardant resin composition is obtained by blending (A) 100 pts. wt. of a thermoplastic resin, (B) 200-300 pts. wt. of an inorganic powder having an aspect ratio (average major axis / average thickness) of 8-30, and (C) 1-30 pts. wt. of an organo polysiloxane. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a non-halogen flame retardant resin composition that does not generate halogen gas during combustion, exhibits sufficiently high flame retardance with a smaller amount of metal hydroxide than conventional, and is excellent in environmental safety.

  Since thermoplastic resins are flammable, various flame retarding techniques have been proposed for applications that require flame retardancy. Conventionally, a flame retardant formulation in which a halogen-based flame retardant such as a bromine compound having excellent flame retardancy and antimony oxide is blended in a resin has been widely used. Halogen flame retardant exhibits an excellent flame retardant effect due to radical trapping action and generation of non-flammable gas. However, since a halogen-based flame retardant generates a large amount of toxic gas at the time of a fire, recently, the emergence of a flame-retardant resin composition having a halogen-free formulation has been strongly desired.

  In recent years, various techniques using metal hydroxides such as magnesium hydroxide have been proposed for flame retardant formulations of polyolefin resins used as insulators and sheets for electric wires and cables.

  However, metal hydroxide has the advantages of low toxicity, low smoke generation and low corrosiveness, and exerts flame retardancy by releasing crystal water during combustion, but its flame retardancy is not strong Even when 100 parts by mass of an equivalent amount of 100 parts by mass of polyolefin as the base resin is blended, the oxygen consumption index (hereinafter referred to as LOI) shows only a numerical value of 30 or less even in an optimal combination.

  When a metal hydroxide and silicone subjected to a surface treatment are added to polyolefin, flame retardancy is improved, but it is still not sufficient, and a composition having higher flame retardancy is desired.

  Patent Documents 1 to 3 are listed as examples of using the surface-treated metal hydroxide. Moreover, as a thing which limited the shape of the metal hydroxide, patent document 4 is mentioned. However, the flame retardance (LOI) is still low and insufficient only by blending the surface-treated metal hydroxide in the thermoplastic resin, and it is necessary to blend a large amount of the metal hydroxide.

  Patent Document 5 relates to a hexagonal plate-like crystal form, a metal hydroxide having a specific aspect ratio, and a method for producing the same. As shown in Table 1 of the comparative example of this patent, a thermoplastic resin and a metal can be seen. In a hydroxide-only system, there is no correlation between the difference in aspect ratio and flame retardancy.

  Patent Documents 6 to 9 have been reported as a compound in which a metal hydroxide and an organopolysiloxane are blended in a resin, and a formulation for blending a metal hydroxide and an organopolysiloxane in a thermoplastic resin is already known. However, the flame retardancy is improved even when a normal metal hydroxide or organopolysiloxane is used, but a formulation that exhibits higher flame retardancy is required.

Japanese Patent No. 2825500 Japanese Patent No. 3019225 Japanese Patent No. 3072746 Japanese Patent Laid-Open No. 2000-233924 JP 11-353209 A Japanese Patent Publication No.7-119324 Japanese Patent No. 3051211 Japanese Patent No. 3063759 JP-A-4-226551

  Metal hydroxide has the advantages of low toxicity, low smoke generation, and low corrosivity, and exhibits flame retardancy by releasing crystal water during combustion, but its flame retardancy is not strong, Even when 100 parts by mass of an equivalent amount is blended with 100 parts by mass of polyolefin as the base resin, the oxygen consumption index (hereinafter referred to as LOI) shows only a numerical value of 30 or less even in an optimal combination. When a metal hydroxide and silicone subjected to a surface treatment are added to polyolefin, flame retardancy is improved, but it is still not sufficient, and a composition having higher flame retardancy is desired.

  As a result of studying a composition that improves flame retardancy, the present inventors have found that when 100 parts by mass of various types of magnesium hydroxide are blended with 100 parts by mass of thermoplastic resin, the LOI does not change significantly. -28. However, when various kinds of magnesium hydroxide and organopolysiloxane are blended with EVA, it has been found that the fluctuation of the LOI value is large depending on the kind of magnesium hydroxide.

  Accordingly, magnesium hydroxide classified was kneaded and molded with EVA and organopolysiloxane, respectively, and the LOI was measured. As a result, the LOI was greatly different from 38 to 58, and the difference in LOI was found to correlate with the difference in shape. In particular, plate-shaped magnesium hydroxide was superior in flame retardancy than expected. Specifically, it has been found that a plate-like powder shape having an aspect ratio (average major axis ÷ average thickness) of 8 to 30, preferably 10 to 20 is excellent in synergistic effect in flame retardancy with organopolysiloxane. .

Accordingly, the present invention relates to (A) 100 parts by weight of a thermoplastic resin, (B) 20 to 300 parts by weight of an inorganic powder having an aspect ratio (average major axis / average thickness) of 8 to 30, (C) A non-halogen flame retardant resin composition comprising 1 to 30 parts by weight of an organopolysiloxane having an average degree of polymerization of 2500 to 30000 represented by the average composition formula (1).
R _a SiO _{4-a / 2} (1)
(In the formula, R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and a is a number of 1.9 ≦ a ≦ 2.1.)

  According to the present invention, it is possible to obtain a non-halogen flame-retardant resin composition that does not generate halogen gas at the time of combustion, exhibits sufficiently high flame retardancy with a smaller amount of inorganic flame-retardant powder, and is excellent in environmental safety. it can.

  As the thermoplastic resin of the component (A) in the present invention, low density polyethylene, high density polyethylene, linear low density polyethylene, ultra low density polyethylene, ultra high molecular weight polyethylene, polypropylene, polypropylene elastomer, polystyrene, polystyrene elastomer Saponified ethylene vinyl acetate copolymers such as ABS, ethylene vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl acrylate Various thermoplastic elastomers such as copolymers, ethylene-acrylic acid amide copolymers, ethylene-methacrylic acid copolymers, ethylene-methyl methacrylate copolymers, ethylene-glycidyl methacrylate copolymers, ethylene maleic anhydride, ionomers, etc. Chromatography, ethylene propylene rubber, butyl rubber, SBR, NBR, acrylic rubber, does not may be mentioned silicone rubber are limited to this.

  These may be used alone or in combination of two or more. Among the resins listed above, low density polyethylene, high density polyethylene, linear low density polyethylene, ultra low density polyethylene, ultra high molecular weight polyethylene, polypropylene, ethylene vinyl acetate copolymer, ethylene-ethyl acrylate copolymer And the like have a high synergistic effect in flame retardancy with metal hydroxide and organopolysiloxane.

  As the inorganic powder of component (B) in the present invention, aluminum hydroxide, magnesium hydroxide, antimony trioxide, antimony pentoxide, sodium antimonate, antimony tetraoxide, zinc borate, zirconium compound, molybdenum compound, calcium carbonate , Silica, silicone resin powder, silicone rubber powder, talc, acrylic silicone powder, titanium oxide, wax stone, quartz, diatomaceous earth, sulfide ore, sulfide sinter, graphite, bentonite, kaolinite, activated carbon, carbon black, zinc oxide , Iron oxide, marble, bakelite, Portland cement, SiO powder, boron nitride, synthetic mica, glass beads, mica, sericite, various plastic pulverized products, etc., but the present invention is not limited thereto. . In particular, as a powder for a flame retardant material, a metal hydroxide is excellent, and among them, magnesium hydroxide, aluminum hydroxide, and calcium hydroxide are preferable.

  In addition, even if the above-mentioned inorganic powder is untreated, surface treatment of saturated fatty acid, unsaturated fatty acid, titanate coupling agent, silane coupling agent, silicone oligomer, reactive silicone oil, thermoplastic resin, etc. It may be treated with an agent.

  In the present invention, the inorganic powder of component (B) is preferably composed of an inorganic powder surface-treated with an unsaturated functional group-containing silane compound and an inorganic powder not surface-treated with the silane compound. Moreover, it is preferable that ratio of both consists of 0.5: 99.5-100: 0, especially 20: 80-95: 5. The treatment amount of the silane compound on the surface of the inorganic powder is preferably 0.001 to 5% by mass of the amount of the inorganic powder, and particularly preferably 0.01 to 3% by mass.

  The inorganic powder surface-treated with the unsaturated functional group-containing silane compound is cross-linked with the thermoplastic resin, the unsaturated functional groups, or the unsaturated functional group-containing organopolysiloxane with the peroxide to increase the strength of the composition.

  Examples of the unsaturated functional group-containing silane used for the surface treatment of inorganic powder include vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (β-methoxyethoxy) silane, and γ- (methacryloxypropyl) trimethoxysilane. be able to.

  In the present invention, when the aspect ratio (average major axis / average thickness) of the inorganic powder of the component (B) is in the range of 8 to 30, the synergistic effect of flame retardancy is excellent. A more preferable aspect ratio is 10 to 20, most preferably 10 to 15, and the flame retardant synergistic effect is high. If it is less than 8, the LOI will be low, and if it exceeds 30, it will be elongated and fibrous, and the addition and dispersion in the composition may be inferior.

  The blending amount of (B) inorganic powder in the present invention is 20 to 300 parts by weight, preferably 50 to 150 parts by weight, based on 100 parts by weight of component (A). When the component (B) is less than 20 parts by weight, the flame retardant effect is insufficient, and when it exceeds 300 parts by weight, the hardness increases.

The organopolysiloxane of component (C) in the present invention has a structure represented by the following formula (1).
R _a SiO _{4-a / 2} (1)
(In the formula, R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and a is a number of 1.9 ≦ a ≦ 2.1.)

  R in the above formula (1) is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, such as alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group. Group, vinyl group, allyl group, butenyl group and other alkenyl groups, phenyl group, tolyl group and other aryl groups, and part or all of hydrogen atoms bonded to carbon atoms of these groups are substituted with cyano groups or the like 2 -Substituted hydrocarbon groups such as cyanoethyl groups are exemplified, but from the viewpoint of the adhesion of powder to the wall of a weighing machine or transportation device and the fluidity during molding, all or most of the substituents are methyl groups. Preferably there is.

  Further, the molecular structure of the organopolysiloxane is preferably a straight chain, but there is no problem even if it includes a part of a branched molecular structure. Therefore, a is preferably a number in the range of 1.9 ≦ a ≦ 2.1, more preferably a number in the range of 1.95 ≦ a ≦ 2.05.

  The average degree of polymerization, which is the number of repeating siloxane units in formula (1), is preferably in the range of 2500 to 30000, more preferably in the range of 3000 to 15000 for the organopolysiloxane used in the present invention. . If the average degree of polymerization is less than 2500, the mechanical properties of the resin molded product may deteriorate, which is not preferable. Although the organopolysiloxane is excellent in fluidity at the time of molding, it is preferable that the average degree of polymerization exceeds 30000 because the composition becomes too viscous and stirring during production becomes difficult. Absent.

  In addition, organopolysiloxane contains low molecular weight siloxane (meaning low boiling point siloxane that easily evaporates in the air, and has a molecular weight of 750 or less). It has been. In order to prevent contact failure, the amount of low-molecular siloxane contained in the final product is preferably 5000 ppm or less, preferably 2000 ppm or less.

Specific examples of the formula (1) include those represented by the following formula.
R ₃ SiO (R ₂ SiO) _m (RXSiO) _n SiR _{3
X: -O (R 2 SiO)} r SiR 3
Here, examples of R include the same monovalent hydrocarbon groups having 1 to 10 carbon atoms as described above. Examples thereof include alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group, and a cyclohexyl group. A cycloalkyl group, a phenyl group, an aryl group, or an unsubstituted or substituted 1 such as a trifluoropropyl group or a cyanoethyl group in which a part or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with a cyano group or the like. A group selected from a valent hydrocarbon group and the like. It is preferable in view of characteristics that at least 80% of R contained in the whole organopolysiloxane of component (C) is a methyl group.

  M is an integer greater than or equal to 2500, n is an integer greater than or equal to 0, r is an integer greater than or equal to 1, and is in a range satisfying 2500 ≦ m + n × r ≦ 30000.

  In producing the composition of the present invention, 1 to 30% by mass of the organopolysiloxane represented by the above formula (1) with respect to the powder having an aspect ratio (average major axis ÷ average thickness) of 8 to 30. In a proportion, an organopolysiloxane-treated powder previously treated with a pressure kneader or the like may be blended in the thermoplastic resin.

  In this case, the amount of the organopolysiloxane in which the metal hydroxide is dispersed needs to be 1% by mass to 30% by mass of the total weight of the metal hydroxide and the organopolysiloxane. If it is less than 1% by mass, the improvement in flame retardancy is small. If it exceeds 30% by mass, it becomes rubbery and bulky, so that dispersion of silicone in the next step may be deteriorated, and flame retardancy may be reduced.

  In the present invention, the blending amount of (C) organopolysiloxane having a high degree of polymerization is 1.0 to 30 parts by weight, preferably 1.5 to 20 parts by weight, more preferably 100 parts by weight of (A) thermoplastic resin. Is preferably blended in an amount of 2.0 to 10 parts by mass. When the blending amount is less than 1.0 part by mass, sufficient flame retardancy is not exhibited, and when it exceeds 30 parts by mass, it becomes rubbery and bulky. Sexual decline may be seen. (C) component in this invention may use 2 or more types together.

  In the non-halogen flame retardant resin composition of the present invention, additives can be blended depending on the purpose as long as the characteristics are not impaired. Examples of the additives include antioxidants, ultraviolet absorbers, stabilizers, light stabilizers, compatibilizers, other types of non-halogen flame retardants, lubricants, fillers, adhesion aids, and rust inhibitors.

  Antioxidants usable in the present invention include 2,6-di-tert-butyl-4-methylphenol and n-octadecyl-3- (3 ′, 5′-di-tert-butyl-4-hydroxyphenyl). ) Propionate, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 4 , 4′-butylidenebis- (3-methyl-6-tert-butylphenol), triethylene glycol-bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8 10-tetraoxaspiro [5,5] undecane, 4,4-thiobis- (2-tert-butyl-5-methylphenol), 2,2-methylenebis- (6-tert-butyl-methylphenol), 4, 4-methylenebis- (2,6-di-t-butylphenol), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris Nonylphenyl phosphite, tris (2,4-di-t-butylphenyl) phosphite, distearyl pentaerythritol phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol phosphite, bis (2, 6-di-t-butyl-4-methylphenyl) pentaerythritol phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) Nyl) octyl phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylene-di-phosphonite, dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′- Thiodipropionate, pentaerythritol tetrakis (3-laurylthiopropionate), 2,5,7,8-tetramethyl-2 (4,8,12-trimethyldecyl) chroman-2-ol, 5,7- Di-t-butyl-3- (3,4-dimethylphenyl) -3H-benzofuran-2-one, 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4 , 6-Dipentylphenyl acrylate, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate , Tetrakis (methylene) -3- (dodecylthiopropionate) methane and the like.

  Stabilizers that can be used in the present invention include lithium stearate, magnesium stearate, calcium laurate, calcium ricinoleate, calcium stearate, barium laurate, barium ricinoleate, barium stearate, zinc laurate, zinc ricinoleate, stearin Various metal soap stabilizers such as zinc acid, various organic tin stabilizers such as laurate, malate and mercapto, various lead stabilizers such as lead stearate and tribasic lead sulfate, and epoxy compounds such as epoxidized vegetable oil Phosphite compounds such as alkyl allyl phosphite and trialkyl phosphite, β-diketone compounds such as dibenzoylmethane and dehydroacetic acid, polyols such as sorbitol, mannitol and pentaerythritol, hydrotalcites and Mention may be made of a light class.

  Examples of light stabilizers that can be used in the present invention include benzotriazole-based UV absorbers, benzophenone-based UV absorbers, salicylate-based UV absorbers, cyanoacrylate-based UV absorbers, oxalic anilide-based UV absorbers, hindered amine-based light stabilizers. Agents and the like.

Examples of the compatibilizer usable in the present invention include acrylic organopolysiloxane copolymers, partially crosslinked products of silica and organopolysiloxane, silicone powder, MQ resin, anhydrous maleated graft-modified polyolefin, carboxylated graft-modified polyolefin, polyolefin Examples thereof include graft-modified organopolysiloxane.
Examples of the adhesion assistant that can be used in the present invention include various alkoxysilanes.

  When the non-halogen flame retardant resin composition of the present invention is added with an inorganic flame retardant, a highly polymerized organopolysiloxane, an unsaturated group-containing organopolysiloxane, a peroxide and a platinum group element-containing catalyst, It may be heated and mixed in a screw extruder, a screw extruder, a Banbury mixer, or a pressure kneader, and a high-polymerization degree organopolysiloxane, an unsaturated group-containing organopolysiloxane, a peroxide and a platinum group element-containing catalyst Create a masterbatch that contains a thermoplastic resin or a highly polymerized organopolysiloxane, an unsaturated group-containing organopolysiloxane, a peroxide and a platinum group element-containing catalyst, and an inorganic flame retardant. The combination is superior in terms of handleability and dispersibility.

  The non-halogen flame retardant resin composition of the present invention is particularly excellent as a flame retardant tube or flame retardant sheet molding material.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to a following example, unless the summary is exceeded. In addition, the number of the raw material column of Table 1 shows a mass part.

Examples and Comparative Examples <Production and Evaluation Methods for Powder Products>
For each raw material shown in Table 1, the aspect ratio (average major axis ÷ average thickness), specific surface area (m ² / g) and average particle size (μm) were determined by the following evaluation methods.

Evaluation method (a) Average major axis and average thickness: After taking a photograph of powder obtained by classification with an electron microscope, the major axis and thickness of 20 powders are measured from the photograph, and the average major axis and the average thickness are determined. Asked.

(B) Specific surface area and average particle diameter; 0.3 parts by weight of nonionic surfactant and 20 parts by weight of water are added to 0.1 parts by weight of the inorganic powder, and the powder is dispersed using an ultrasonic vibrator or the like. Measurement was performed using Multisizer II (manufactured by Coulter, Inc.).

<Flame retardancy evaluation method>
With respect to 100 parts by mass of EVA resin (Evaflex 360, manufactured by Mitsui DuPont Polychemical Co., Ltd.), magnesium hydroxide, organopolysiloxane A and organopolysiloxane B represented by the following average formula, in the ratios in Table 1 and Table 2, Organopolysiloxane C (KF-96 Shin-Etsu Chemical Co., Ltd., trade name) having a viscosity of 10,000 mm ² / s at 25 ° C. is blended, and 150 ° C., 10 minutes, 30 rpm in a lab plast mill (manufactured by Toyo Seiki Co., Ltd.). After mixing under conditions, a sample piece was prepared by press molding, and the oxygen consumption index (LOI) was measured.

Organopolysiloxane A
[(CH ₃ ) ₃ SiO _1/2 ] ₂ [(CH ₃ ) ₂ SiO _2/2 ] ₇₀₀₀
Organopolysiloxane B
[(CH ₃ ) ₃ SiO _1/2 ] ₃ (φ ₂ SiO _2/2 ) ₁₀ [(CH ₃ ) ₂ SiO _2/2 ] ₃₀₀₀ (CH ₃ SiO _3/2 ) ₁
Organopolysiloxane C
[(CH ₃ ) ₃ SiO _1/2 ] ₂ [(CH ₃ ) ₂ SiO _2/2 ] ₈₀₀
(Here, φ represents a phenyl group.)

The results in Tables 1 and 2 demonstrate the effectiveness of the present invention.

表１及び表２の結果は本発明の有効性を実証するものである。

The results in Tables 1 and 2 demonstrate the effectiveness of the present invention.

  In the mixed composition of the resin and various magnesium hydroxides (Comparative Examples 3 to 7), the flame retardancy (LOI) is 28.0 regardless of the differences in the characteristics (aspect ratio, average particle diameter, specific surface area) of the magnesium hydroxide. No difference is seen with ~ 28.3. However, when silicone having a high polymerization degree is blended with resin and various magnesium hydroxides (Comparative Examples 1, 2, 8, and Examples 1-4), the flame retardancy is as large as 38-58 depending on the type of magnesium hydroxide. The difference comes out. It can be confirmed that this difference in flame retardancy has a correlation between the aspect ratio and the degree of polymerization of the silicone, regardless of the average particle diameter and the specific surface area.

Claims (6)

(A) With respect to 100 parts by weight of the thermoplastic resin, (B) 20 to 300 parts by mass of inorganic powder having an aspect ratio (average major axis ÷ average thickness) of 8 to 30, and (C) the organopolysiloxane 1 to 30 parts by weight of an organopolysiloxane having an average degree of polymerization of 2500 to 30000 represented by the following average composition formula (1). A flame retardant resin composition.
R _a SiO _{4-a / 2} (1)
(In the formula, R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and a is a number of 1.9 ≦ a ≦ 2.1.) The non-halogen flame retardant resin composition according to claim 1, wherein the inorganic flame retardant as the component (B) comprises a metal hydroxide. The inorganic flame retardant of component (B) is composed of an inorganic flame retardant surface-treated with an unsaturated functional group-containing silane compound and an inorganic flame retardant not surface-treated with the silane compound, and the ratio of the two is 0. The non-halogen flame retardant resin composition according to claim 1, wherein the composition is 5: 99.5 to 100: 0. The non-halogen flame retardant resin composition according to claim 3, wherein the amount of the unsaturated functional group-containing silane compound applied to the surface of the inorganic flame retardant is 0.001 to 5% by weight of the amount of the inorganic flame retardant. . The non-halogen flame retardant resin composition according to any one of claims 1 to 4, wherein the thermoplastic resin is a polyolefin resin. The inorganic functional flame retardant not treated with an unsaturated functional group-containing silane is previously surface-treated with an organopolysiloxane or a resin mixture containing an organopolysiloxane according to any one of claims 1 to 5. The non-halogen flame retardant resin composition described.