JP3502444B2 - Flame retardant composition and flame retardant cable - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flame-retardant composition and a flame-retardant cable having a flame-retardant layer comprising the composition,
More specifically, it relates to a flame-retardant composition and a flame-retardant cable characterized by using a specific syndiotactic polypropylene.

[0002]

2. Description of the Related Art Conventionally, a base polymer such as high density polyethylene (HDPE) has a high polarity such as decabromophenyl ether and magnesium hydroxide [Mg (OH) ₂ ]. A flame-retardant cable having a flame-retardant layer made of a flame-retardant composition containing a flame-retardant is known. However, in order to impart a high degree of flame retardancy to this flame retardant layer, it is necessary to add a large amount of the above flame retardant, which is a drawback that mechanical properties are significantly reduced.

A first object of the present invention is to provide a flame-retardant composition capable of easily forming a coating layer having excellent flame retardancy and mechanical properties and electrical properties required as a cable coating material. Is. The second object of the present invention is to
It is an object of the present invention to provide a flame-retardant cable having excellent flame retardancy and mechanical and electrical characteristics required as a cable coating material.

[0004]

The present inventors have studied various base polymers in order to solve the above problems, and as a result, have found that a specific syndiotactic pentad fraction and a melt flow rate (hereinafter referred to as MFR and It has been found that a composition comprising syndiotactic polypropylene (which may be abbreviated) and a flame retardant has excellent mechanical properties, moldability and electrical properties.

The present invention has been completed based on the above findings, and a first object of the present invention is to have a syndiotactic pentad fraction of 0.7 or more and a melt flow rate of 0.1. Achieved by a flame retardant composition comprising a syndiotactic polypropylene that is ˜20 g / 10 min and a flame retardant. This flame-retardant composition desirably contains 5 to 20 parts of an organic and / or inorganic flame retardant with respect to 100 parts by weight of syndiotactic polypropylene.
It contains 0 parts by weight. The second object of the present invention is achieved by a flame-retardant cable having a flame-retardant layer made of the above composition.

The syndiotactic polypropylene used as the base polymer in the flame-retardant composition of the present invention is not only a homopolymer of propylene having a syndiotactic structure, but also a copolymer of propylene and other olefins. This is a concept including coalescence, and in the following description, the copolymer is referred to as s-PP. In the present invention, homopolymer s-PP is preferred.

The preferred molecular weight of s-PP is 3,0.
00-400,000, more preferably 10,000
~ 200,000.

In the present invention, the syndiotactic pentad fraction of s-PP must be 0.7 or more. Here, the syndiotactic pentad fraction refers to 13 C-NMR measured at 135 ° C. with a 1,2,4-trichlorobenzene solution at 67.8 MHz.
In the spectrum, the ratio of the peak intensity attributed to all the methyl groups of the propylene unit of the peak intensity (peak intensity of the methyl group attributed to the syndiotactic pentad chain) observed at 20.2 ppm based on tetramethylsilane. Say. Since s-PP having a syndiotactic pentad fraction of less than 0.7 has a low melting point and also has low electrical breakdown strength and mechanical properties, it is used as a base polymer for the flame retardant composition of the present invention. Is not preferable.
The syndiotactic pentad fraction is preferably 0.8 to 0.95 from the viewpoint of flexibility, and more preferably 0.86 to 0.95 from the viewpoint of workability.

Further, the s-PP used in the present invention is
It is necessary that the melt flow rate (MFR) specified by ASTM-D-1238 has a range of 0.1 to 20 g / 10 minutes. S-PP with an MFR of more than 20 g / 10 min has too much fluidity at high temperatures, conversely s-PP with an MFR of less than 0.1 g / 10 min has too little fluidity, and When any of them is used as the flame-retardant composition of the present invention, workability becomes difficult. A preferable range of the MFR is 0.3 to 15 g / 10 minutes from the viewpoint of high temperature fluidity, and a more preferable range is 0.5 to 10 g / 10 minutes from the viewpoint of extrusion processability.

There is no particular limitation on the method for producing s-PP. That is, as the polymerization catalyst used, an organometallic complex catalyst having a symmetrical or asymmetrical molecular structure, for example, a stereospecific polymerization catalyst such as a metallocene compound can be used. Also, the polymerization conditions are not particularly limited, and the polymerization can be carried out by a method such as a bulk polymerization method, a gas phase polymerization method, a solution polymerization method using an inert solvent, or the like.

The s-PP used in the present invention has excellent fluidity over a wide range of temperatures and is excellent in workability. Also, the strength at break is higher than that of HDPE, which is one of the conventional materials. Further, the impulse breakdown electric field strength of s-PP at room temperature is 10 to 25% higher than that of the conventional LDPE and 110 to 140% higher than that of i-PP, and the AC breakdown electric field strength at room temperature is higher than that of LDPE. 2.5-8.5%, cross-linked L
14-20% than DPE, 45-55 than i-PP
% Is also high.

The flame retardant composition of the present invention comprises the above s-PP and an inorganic and / or organic flame retardant. Examples of the flame retardant include the following inorganic or organic flame retardants. [Inorganic Flame Retardant] Antimony Flame Retardant: For example, antimony trioxide, antimony pentoxide, sodium antimonate or composite antimony flame retardant. Metal oxide hydrates: for example, aluminum hydroxide, magnesium hydroxide. Metal salts of boric acid: For example, zinc borate, aluminum borate,
Zircon borate, barium borate, and other double salts of boric acid. Red phosphorus (Nova Red, etc.).

[Organic Flame Retardant] Phosphoric Acid Ester and Halogen-Containing Phosphorus Compound: For example, tris (chloroethyl)
Phosphate, tris (monochloropropyl) phosphate, tris (dichloropropyl) phosphate, triallyl phosphate, tris (3-hydroxypropyl) phosphine oxide, tris (tribromophenyl) phosphate, tetrakis (2-chloroethyl) ethylene diphosphate, glycidyl -Α-methyl-β
-Di (butoxy) phosphinyl propionate, dibutylhydroxymethylphosphonate, di (butoxy) phosphinyl propylamide, dimethylmethylphosphonate, tris (2-chloroethyl) orthophosphate, ethylene bis tris (2 -Cyanoethyl) phosphonium bromide, di- (polyoxyethylene) -hydroxymethyl phosphate, β-chloroethyl acid phosphate, β-chloropropyl phosphate, butylpyrophosphate, butyl acid phosphate, butoxyethyl acid phosphate,
2-Ethylhexyl acid phosphate, melamine phosphate.

Chlorine flame retardant: for example, chlorinated paraffin, chlorinated polyolefin, chlorinated polyethylene, dechlorane plus, perchlorocyclopentadecane, a mixture of chlorinated paraffin and antimony trioxide.

Brominated flame retardants: for example, hexabromobenzene, decabromodiphenyl oxide, polydibromophenylene oxide, bis (tribromophenoxy) ethane, ethylene bis tetrabromophthalimide, ethylene bis dibromonorbornane dicarboximide, dibromoethyl -Dibromocyclohexane, dibromoneopentyl glycol, tribromophenol, tribromophenol allyl ether, tetrabromo-bisphenol A derivative, tetrabromo-bisphenol S, tetradecabromo-diphenoxybenzene, tris-
(2,3-Dibromopropyl-1) -isocyanurate, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, pentabromophenol, 2,2
-Bis (4-hydroxyethoxy-3,5-dibromophenyl) propane, pentabromotoluene, pentabromodiphenyl oxide, hexabromocyclododecane,
Hexabromodiphenyl ether, octabromophenol ether, octabromodiphenyl ether, octabromodiphenyl oxide, dibromoneopentyl glycol tetracarbonate, bis (tribromophenyl) fumaramide, N-methylhexabromodiphenylamine, brominated epoxy resin, brominated polystyrene, Brominated flame retardant.

Reactive flame retardant: for example, polybromodiallyl phthalate, tetrabromophthalic anhydride, tetrabromobisphenol A, dibromocresyl glycidyl ether, dibromophenol, diethoxy-bis-
(2-hydroxyethyl) -aminomethylphosphonate, dibromocresol, tribromophenol, phenylphosphonic acid dichloride, diethylphenyl.
Phosphonates, tricresyl phosphates, dimethylphenyl phosphonates and diallyl chlorendates.

In the case of adding an inorganic flame retardant to the above-mentioned s-PP, the flame-retardant composition of the present invention contains the s-PP100.
50 to 200 parts by weight, preferably 80 to 1 per part by weight
50 parts by weight, when adding an organic flame retardant other than the inorganic flame retardant, 5 to 50 parts by weight, preferably 15 to 30 parts by weight per 100 parts by weight of the s-PP, further inorganic and organic flame retardants are used in combination. When used as
5 to 200 parts by weight, preferably 55 to 200 parts by weight, is added per 100 parts by weight of PP.
If the amount of the flame retardant compounded is less than the above range, the flame retardant function is not sufficiently exerted, while if it exceeds the above range, mechanical properties and electrical properties tend to be deteriorated. In the present invention, it is preferable to use inorganic and organic flame retardants in combination from the viewpoint of improving flame retardancy.

The above flame retardant composition is prepared by mixing s-PP with a flame retardant by a method known per se. In the preparation of the flame retardant composition, when the flame retardant used is an inorganic solid flame retardant, in order to prevent deterioration of mechanical properties of the flame retardant composition, 100 weight% of the solid flame retardant is used as necessary. The coupling agent may be added in an amount of 0.05 to 5 parts by weight, preferably 0.5 to 3 parts by weight per part. As this coupling agent, a silane coupling agent and a titanate coupling agent are preferably used.

The flame-retardant composition of the present invention further contains EP rubber, EVA, in order to impart flexibility to the coating layer.
Flexible polymers such as EEA, EMA, ethylene-poly-α-olefins can be added. In this case, the addition amount is s-
PP / flexible polymer = 99/1 to 70/30, preferably about 95/5 to 80/20.

The flame-retardant composition of the present invention may contain carbon black in order to improve weather resistance. As the mixing ratio, 0.5 to 40 parts by weight of carbon black is added to 100 parts by weight of s-PP,
Preferably about 1.0 to 10 parts by weight can be blended. As the carbon black, usually used ones such as furnace blacks such as FEF, HAF and SRF, thermal blacks such as MT or channel blacks, etc. are used especially from the viewpoint of improving flame retardancy and mechanical properties. It is preferable to use black or thermal black.

In addition, the flame-retardant composition of the present invention may contain a tin compound, an iron compound, a nickel compound, if necessary.
A smoke suppressant such as a molybdenum compound or a silicon compound may be added.

Furthermore, the flame-retardant composition of the present invention contains, if necessary, antioxidants or stabilizers such as hindered phenols, amines or thioethers, and copper damage prevention such as amides and hydrazide compounds. Agent, UV protection agent such as benzophenone type, benzoin type, lubricant such as higher fatty acid type or its metal salt type, biological aid such as processing aid, ant-prevention agent and rodent-proofing agent, pigment, silica, clay, etc. You may mix | blend the additive normally used with plastics, such as an agent.

As described above, since the flame-retardant composition of the present invention uses s-PP as a base polymer, it has a conventional HD content.
Compared with the composition using PE as a base polymer, mechanical properties,
Excellent electrical characteristics. More specifically, it has high breaking strength, excellent elongation, and excellent electrical breaking strength, and is therefore used as a flame-retardant layer for flame-retardant cables, particularly as an insulating layer and outermost layer.

Since the flame-retardant cable of the present invention has a flame-retardant layer made of the above-mentioned flame-retardant composition, examples thereof include power cables and communication cables. This flame-retardant cable is manufactured by a general cable manufacturing method. When the flame-retardant layer is an insulating layer, it is usually 0.2 to 20 mm, preferably 0.5.
It is formed to a thickness of about 15 mm. When the flame-retardant layer is the outermost layer, it is usually 0.5 to 10 mm, preferably 1 to
It is formed to a thickness of about 5 mm.

Since the flame-retardant cable of the present invention has a flame-retardant layer made of the above-mentioned flame-retardant composition, it has excellent flame-retardant properties and electrical and mechanical properties required for cable protection. To have.

[0026]

EXAMPLES Examples are shown below to more specifically describe the present invention. The present invention is not limited to these examples. Examples 1 to 8 As shown in Table 1, with respect to 100 parts by weight of various syndiotactic polypropylene having a predetermined syndiotactic pentad fraction and melt flow rate, an inorganic flame retardant Mg (OH) was used as a flame retardant. ₂ to 100 parts by weight,
Each composition was prepared by adding 5 parts by weight of FEF carbon black. Each of these compositions was molded in a compression molding machine at 180 ° C. for 15 minutes and then slowly cooled to a thickness of 1.0 m.
m sheets were produced respectively. The mechanical properties of each of the obtained sheets were measured according to JIS K7113. Furthermore, flame retardancy (0
I: oxygen index) was measured. Table 1 shows each measurement result.
It was shown to.

Further, similarly to the above, a thickness of 0.3 is separately set.
mm sheets were prepared and subjected to an impulse breakdown test and an AC breakdown test with the modified McCown electrode system. In the impulse breakdown test, a negative impulse standard wave of 1 × 40 μsec was applied by a step-up boosting method of applying 5 KV / 3 times with an initial value of 70% of the expected breakdown voltage. In the AC breakdown test, 70% of the expected breakdown voltage was set as the initial value, and the voltage was applied by the step-up boosting method of applying 1 KV / 1 minute. In the impulse breakdown test and the AC breakdown test, data of 10 samples was collected for each condition, and after the wipe analysis, the breakdown value at a breakdown probability of 63.3% was taken as the breakdown voltage value of the sample. The electrical breakdown characteristics at 25 ° C are shown in Table 1.

The syndiotactic pentad fraction (rrrr) is 2 based on tetramethylsilane in the 13 C-NMR spectrum measured at 135 ° C. in 1,2,4-trichlorobenzene solution at 67.8 MHz.
The ratio of the peak intensity attributed to all methyl groups of the propylene unit of the peak intensity observed at 0.2 ppm (peak intensity of methyl group attributed to syndiotactic pentad chain) is shown. In addition, the melt flow rate (MF
R) indicates a value measured according to ASTM-D-1238. In addition, as a mechanical property, tensile fracture strength (T
S) and tensile breaking elongation (Elo.) Were measured, and the values of maximum tensile stress and breaking elongation are shown in Table 1, respectively.

Comparative Examples 1 and 2 In place of the s-PP used in the above examples, s-PP having a syndiotactic pentad fraction of 0.6 was used (Comparative Example 1) and HDPE was used ( A composition was prepared in the same manner except for Comparative Example 2), and then a sheet was prepared in a compression molding machine in the same manner as in Example. Table 1 shows the syndiotactic pentad fraction (rrrr), the melt flow rate (MFR), and the flame retardancy, mechanical properties, and electrical breakdown properties of the obtained sheets.

Example 9 Example 1 is the same as Example 1 except that 30 parts by weight of organic flame retardant decabromodiphenyl ether and 15 parts by weight of inorganic flame retardant antimony trioxide were used as the flame retardant.
A composition was prepared in the same manner as in.

Example 10 In Example 1, except that as the flame retardant, 30 parts by weight of organic flame retardant dechlorane plus 10 parts by weight of tricresyl phosphate and 15 parts by weight of aluminum hydroxide as an inorganic flame retardant were used. A composition was prepared in the same manner as in Example 1.

Using the compositions prepared in Examples 9 to 10 above, a sheet was prepared in the same manner as in Example 1, the mechanical properties and flame retardancy were measured, and the impulse breakdown test and AC breakdown were performed. The test was conducted. The results are shown in Table 1.

[0033]

[Table 1]

Example 11 The outer periphery of a conductor (copper stranded wire having an outer diameter of 10 mm) was extrusion-coated with three layers of an inner semiconductive layer, an insulating layer and an outer semiconductive layer by a tandem extrusion method. The composition prepared in Example 1 was used as the insulating layer to form a thickness of 4.0 mm. Also,
EVA (VA = 25% by weight) 100 as an internal semiconductive layer
A composition in which 50 parts by weight of acetylene black was mixed with parts by weight was used to form a thickness of 1.0 mm. Further, as the external semi-conductive layer, the carbon blended EVA was formed to a thickness of 0.3 mm. Then, the above extruded coating was cooled, and a single-core sheath cable having a soft polyvinyl chloride sheath (thickness 1.0 mm) formed by extrusion coating was obtained. The insulating layer of the obtained power cable had flame retardancy, high breaking strength, excellent elongation, and electrical breaking strength. This power cable had excellent electrical and mechanical properties.

Example 12 In addition to the power cable prepared in Example 11, Example 1 was used.
The composition prepared in 1. was extrusion coated to form an anticorrosion layer to prepare a power cable. The obtained power cable had excellent flame retardancy, electrical properties, and mechanical properties.

[0036]

As described above, since the flame-retardant composition of the present invention uses s-PP as a base polymer, it has a conventional HD content.
Compared with the composition using PE as a base polymer, mechanical properties,
Since it has excellent electrical properties, that is, it has high strength at break, excellent elongation, and excellent electrical breakdown strength. Therefore, the flame-retardant composition of the present invention can be suitably used as a flame-retardant layer for a flame-retardant cable. Moreover, this flame-retardant composition is also excellent in processability. Further, the flame-retardant cable of the present invention has excellent flame retardancy and also has the electrical characteristics and mechanical characteristics required for cable protection.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-25485 (JP, A) JP-A-4-226552 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 23/00-23/36 C08K 3/00-13/08 H01B 3/30 H01B 7/34

Claims (6)

(57) [Claims] 1. The syndiotactic pentad fraction is 0.7 or more, and the melt flow rate is 0.1 to 0.1.
A flame-retardant composition for a flame-retardant cable, which comprises 20 g / 10 minutes of syndiotactic polypropylene and a flame retardant. 2. The syndiotactic pentad fraction is
The flame-retardant composition according to claim 1, which is 0.8 to 0.95. 3. Syndiotactic polypropylene 1
5 parts by weight of organic and / or inorganic flame retardant per 100 parts by weight
The flame-retardant composition according to claim 1 or 2 , wherein the flame-retardant composition is contained in an amount of about 200 parts by weight. 4. A flame-retardant cable having a flame retardant layer made of the flame retardant composition according to any one of claims 1-3. 5. The flame-retardant cable according to claim 4 , wherein the flame-retardant layer is an insulating layer. 6. The flame-retardant cable according to claim 4 , wherein the flame-retardant layer is the outermost layer.