JPH09316257A - Non-halogen-based flame retardant crosslinked polyolefin insulated wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a non-halogen-based flame retardant crosslinked polyolefin insulated wire having a sheath comprising a specific non-halogen-based polyolefin composition and excellent in mechanical characteristic and processability. SOLUTION: This crosslinked polyolefin insulated wire has a sheath comprising a non-halogen-based polyolefin composition composed of (A) 100 pts.wt. polyolefin resin obtained by grafting preferably 1-5 pts.wt. organic silane compound such as vinyltrimethoxysilane, (B) preferably 30-80 pts.wt. non-halogen- based flame retardant compound such as melamine or red phosphorus constituted of a phosphorus compound, a nitrogen compound, a phenol resin and an expanded graphite having <=70% amount unpassable through 80 mesh sieve and (C) a silanol catalyst such as dibutyltin dilaurate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a halogen-free flame-retardant cross-linked polyolefin insulated wire which is excellent in mechanical properties, halogen-free and flame-retardant.

[0002]

2. Description of the Related Art Flame-retardant cross-linked polyolefin insulated wires are flame-retarded because a polyolefin resin, which is a base resin, is extremely easy to burn, so that halogen-based flame retardants have been conventionally used. However, although halogen-based flame retardants have a very high flame retardant effect, drawbacks such as generation of harmful gas during combustion and environmental problems have been found. Therefore, non-halogenation using magnesium hydroxide has been proposed in Japanese Examined Patent Publication No. 58-54443 and the like. However, since the required flame retardancy is severe, conventionally known non-halogen flame-retardant compositions are adequately addressed. There was a problem that I could not do it. Also, JP-A-6-25
No. 476 proposes non-halogen flame retardation using expansive graphite containing 80% or more of 80 mesh-on by classification with red phosphorus, but this method certainly improves the flame retardancy but does not Since the particle size is large, the molding appearance is significantly reduced, and there is a problem that it cannot be used in practice.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a non-halogen flame-retardant cross-linked polyolefin insulated wire which is non-halogen and has improved flame retardancy with almost no deterioration in properties.

[0004]

DISCLOSURE OF THE INVENTION As a result of studying the non-halogen flame retardation of flame-retardant cross-linked polyolefin insulated wires, the present inventors found that the flame retardancy is improved by a method of simply adding a phosphorus compound, a nitrogen compound or the like. It is necessary to add a large amount, and it has been found that when the addition amount is increased, defects such as bleeding and deterioration of mechanical properties occur. Further, even in the method of blending a phenol resin, which has better flame retardancy than a polyolefin resin, a large amount of addition is required to improve the flame retardancy, and the impact resistance remarkably deteriorates when the amount is increased.

Therefore, as a result of earnestly studying synergistically improving the flame retardancy by combining flame retardant compounds having different mechanisms, a phosphorus compound which forms a carbonized film, a nitrogen compound which promotes carbonization, When the shell-forming phenolic resin and expansive graphite that expands and has adiabatic action are used together, each flame-retardant mechanism acts synergistically, and 80 mesh-on, which had a small flame-retardant improvement effect in the past, is 70% or less. It was found that even when the expansive graphite of No. 3 was used, the flame retardancy was dramatically improved without the occurrence of defects such as impact resistance deterioration and bleeding, and the present invention was completed.

That is, according to the present invention, a polyolefin resin (A) grafted with an organosilane compound, a phosphorus compound, a nitrogen compound, a phenol resin, and 80 mesh-on are 70%.
A non-halogen system having a sheath obtained by melt-extruding a non-halogen polyolefin composition comprising the following non-halogen flame retardant compound (B) composed of expandable graphite and silanol catalyst (C) Flame-retardant cross-linked polyolefin insulated wire, preferably non-halogen flame-retardant cross-linking polyolefin, wherein non-halogen flame-retardant compound (B) is expandable graphite with ammonium polyphosphate, phenol novolac resin and 80 mesh on 70% or less. It relates to insulated wires.

The non-halogen flame-retardant compound (B) has a phosphorus compound having an oxygen blocking action, a nitrogen compound having a carbonization promoting action, a phenol resin having a shell-forming property at the time of combustion, and an adiabatic action by expanding at the time of combustion. It was found that when the expandable graphite contained therein is used in combination, the respective flame retardant mechanisms act synergistically and the flame retardancy is remarkably improved. Further, ammonium polyphosphate having a relatively high phosphorus content in the phosphorus compound and having a remarkable synergistic effect with the phenol resin, phenol novolac resin having a high shell-forming ability in the phenol resin, and 80 mesh-on in the expansive graphite having 70% or less of 70% or less. When expandable graphite is used in combination, excellent flame retardancy can be obtained while maintaining good appearance.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The polyolefin resin used in the polyolefin resin (A) grafted with the organosilane compound used in the present invention is not particularly limited and is commercially available. For example, high-density polyethylene, low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer and the like can be mentioned. Alternatively, they may be used in combination of two or more. Among these polyolefin resins, polyethylene resins are preferable from the viewpoint of low temperature impact resistance.

The organounsaturated silane used in the polyolefin resin (A) grafted with the organosilane compound of the present invention is grafted to the base resin so as to serve as a cross-linking point between the base resins. The organic unsaturated silane used in the present invention has the general formula RR'Si
A compound represented by Y ₂ (R is a monovalent olefinically unsaturated hydrocarbon group, Y is a hydrolyzable organic group, and R ′ is a monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon or the same as Y) Is used. It is desirable to use an organic unsaturated silane in which R ′ is the same as Y and is represented by the general formula RSiY ₃ , and examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane and allyltriethoxysilane. The addition amount of these is 1 with respect to 100 parts by weight of the base resin.
-5 parts by weight. When the amount is less than 1 part by weight, sufficient grafting does not occur, and when the amount is more than 5 parts by weight, molding failure occurs and it is not economical.

The free radical generator used in the polyolefin resin (A) grafted with the organosilane compound of the present invention acts as an initiator of the silane grafting reaction. As the free radical generator used in the present invention, various organic peroxides having a strong polymerization initiation action are used.
The addition amount of these is 0.01 to 1 part by weight.
If it is less than 0.01 part by weight, the silane grafting reaction does not proceed sufficiently, and if it exceeds 1 part by weight, the extrusion processability is deteriorated and the molding surface is deteriorated.

The phenolic resin which is the component (B) of the present invention is a very important component having a carbonization promoting function, a function of forming a shell during combustion, and a function of preventing molten droplets. The phenol resin used in the present invention is not particularly limited and is commercially available. For example, phenols and formalin have a formaldehyde / phenols molar ratio of 0.5 to 1.0. The mixture was charged into a reaction kettle at a mixing ratio, and a catalyst such as oxalic acid, hydrochloric acid, sulfuric acid, and toluenesulfonic acid was further added, followed by heating and refluxing for an appropriate time. It can be obtained by a method in which it is allowed to stand for dehydration and the remaining water and unreacted phenols are removed. These resins or co-condensed phenolic resins obtained by using a plurality of raw material components are used alone or in combination of two or more. Phenol resin is preferably blended in the range of 5 to 30 parts by weight, and if it is 5 parts by weight or less, the effect of improving flame retardancy tends to be insufficient, and if it is 30 parts by weight or more, impact resistance and the like are markedly reduced. To do. Among the phenolic resins, a phenol novolac resin, which has an excellent shell-forming ability during combustion, is preferably used.

The phosphorus compound which is the component (B) of the present invention is an important component having a carbonization promoting function and a function of forming a carbonized film. The phosphorus compound used in the present invention is not particularly limited and is commercially available, for example,
Examples include red phosphorus, ammonium polyphosphate, melamine phosphate, and phosphoric acid ester. 5 to 50 phosphorus compounds
It is preferable to blend in the range of 5 parts by weight, and if it is 5 parts by weight or less, the effect of improving flame retardancy tends to be insufficient.
If it is 0 parts by weight or more, defects such as bleeding and deterioration of mechanical properties occur. Among the phosphorus compounds, ammonium polyphosphate is preferable because it has a large phosphorus content.

The component (B) of the present invention, the nitrogen compound, is an important component that promotes carbonization by a synergistic effect when used in combination with a phenol resin and a phosphorus compound. The nitrogen compound used in the present invention is not particularly limited and is commercially available, and examples thereof include triazine compounds such as melamine and melamine cyanurate.

The expansive graphite containing 80% or less of 80 mesh on which is the component (B) of the present invention exhibits a remarkable synergistic effect when used in combination with a phenol resin and a phosphorus compound, and expands during combustion to block heat. , Is a very important component that has the effect of significantly improving flame retardancy. 8 used in the present invention
Expandable graphite having 0 mesh-on of 70% or less is not particularly limited and is commercially available, and 80 mesh-on can be adjusted to 70% or less by classification or expandable graphite from a graphite raw material having a small particle size. It is obtained by manufacturing. The expansive graphite is preferably blended in the range of 5 to 50 parts by weight, and if it is less than 5 parts by weight, the effect of improving the flame retardancy tends to be insufficient, and if it exceeds 50 parts by weight, the mechanical properties and the like are deteriorated. Defects such as deterioration occur. The particle size of the expandable graphite is preferably 50% to 70% when 80 mesh is on. 8
When 0 mesh-on is 50% or less, the expansion degree tends to be low, so that the effect of improving the flame retardancy tends to be small, and when 80 mesh-on is 70% or more, the appearance is extremely deteriorated.

The silanol condensation catalyst used as the component (C) of the present invention is not particularly limited and is commercially available, for example, dibutyltin dilaurate,
Stannous acetate, dibutyltin diacetate, dibutyltin dioctoate and the like can be mentioned. Organometallic compounds such as lead naphthenate and zinc stearate may be mentioned. The addition amount of these is 0.01 to 3 relative to 100 parts by weight of the polyolefin resin grafted with the organic silane compound.
Parts by weight are preferred. If the amount is less than 0.01 part by weight, a sufficient crosslinking reaction does not proceed, and if the amount is more than 3 parts by weight, crosslinking is locally promoted in the extruder at the time of extrusion and the appearance is remarkably deteriorated.

The method for producing the non-halogen flame-retardant cross-linked polyolefin insulated wire of the present invention is not particularly limited, but a polyolefin resin (A) grafted with an organosilane compound and a non-halogen flame-retardant compound (B) are commonly used. ) And silanol catalyst all at once into the extruder, then set the conductor in the wire feeder, heat the conductor at a predetermined temperature through the pre-heater, form a die through the nipple, and coat with a cooling tank. Cool to. At this time, while passing through the capacitance measuring device and outer diameter measuring device installed on the line, the desired capacitance at the set coating diameter,
Extrusion coating is performed by finely adjusting the linear velocity or the temperature set by the temperature controller so that the appearance can be obtained. The coated wire is inspected for external damage by a spark tester, stored in a predetermined container or the like, and then immersed in warm water for several hours to carry out a crosslinking promotion treatment.

[0017]

EXAMPLES The present invention will be described below with reference to examples, but these are merely examples, and the present invention is not limited to these examples. Visually judge the appearance of extrusion. ○○ ＞ ○ ＞ △ ＞ ×
The order was ∘, and the grade of ◯ or higher was passed. The capacitance was measured by measuring the capacitance of the insulated wire covered with a capacitance monitor, and evaluated by comparison with a predetermined value. The order was ◯>Δ> ×, and the ◯ level was passed. The flame retardance is in the order of ○> × by the vertical combustion test of VW-1 of UL-62 standard,
○ Level was passed. The terminal processability was evaluated by evaluating the degree of deformation of the coated insulated wire during pressure contact with a connector using polybutylene terephthalate, and ○ (maintaining the initial shape)> △
The order of (slightly deformed)> × (largely deformed) was set, and a level of ◯ was accepted. Tensile strength and elongation were according to JIS K6760. The gel fraction was 120 ° C. for 20 hours, and was determined by the xylene immersion method.

Production of Polyolefin Resin Grafted with Organic Unsaturated Silane According to the blending ratio shown in Table 1, first, the organic unsaturated silane and the free radical generating agent are mixed with the polyolefin resin, and the mixture is extruded using an extruder. Kneading was performed at an extrusion temperature of 200 to 250 ° C., strand cutting was performed, and granulation was performed to obtain a polyolefin resin grafted with an organic unsaturated silane.

The polyolefin resin is a high density polyethylene (HDPE, density: 0.968 g / cm ³ , MI;
5.2g / 10min), low density polyethylene (LDP)
E, density; 0.925 g / cm ³ , M.I. I. 2.0 g /
10 min), vinyltrimethoxysilane (VTMOS) was used as the organic unsaturated silane compound, and dicumyl peroxide (DCP) was used as the radical generator.

[0020]

[Table 1]

Manufacture of electric wire The obtained organosilane compound-grafted polyolefin resin (A), non-halogen flame-retardant compound (B) and silanol catalyst (C) are mixed in the proportions shown in Tables 2 to 5, The insulated electric wire was extruded by using a shaft extruder, the electrostatic capacity was measured by a measuring instrument installed on the line at this time, and further cross-linked by immersing in warm water.

As the halogen-free flame-retardant compound (B), phosphorus compounds such as red phosphorus [Nova Excel ST-140 manufactured by Rin Kagaku Co., Ltd.], ammonium polyphosphate [AP
P; Sumitomo Chemical Co., Ltd. Sumysafe P], melamine cyanurate as a Chisso compound [MC-410; Nissan Chemical Co., Ltd.], phenol novolak resin as a phenol resin [PN; Sumitomo Durez Co., Ltd. PR-5147
0], as the expansive graphite, expansive graphite having 80% mesh on 65% [expandable graphite; EXP- manufactured by Chuo Kasei Co., Ltd.]
G 8099-60], 80 mesh on 38% expandable graphite [expandable graphite; manufactured by Chuo Kasei Co., Ltd. EXP-
G 194], 80 mesh on 80% or more of expandable graphite [expandable graphite; manufactured by Chuo Kasei Co., Ltd. EXP-G
8099], 80 mesh 40% expandable graphite [expandable graphite; manufactured by Chuo Kasei Co., Ltd. EXP-G 80
99-40] was used. As the silanol catalyst (C), dibutyltin dilaurate [DBDTL; manufactured by Sansha Kisei Co., Ltd.] was used.

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

[Table 4]

[0026]

[Table 5]

As is apparent from the table, the halogen-free flame-retardant cross-linked polyolefin insulated wire of the present invention is non-halogen, has excellent flame resistance, and has excellent mechanical properties and molding appearance.

Claims (3)

[Claims] 1. A non-halogen flame-retardant compound (B) composed of a polyolefin resin (A) grafted with an organosilane compound, a phosphorus compound, a nitrogen compound, a phenol resin and an expansive graphite containing 80 mesh-on at 70% or less. )
And a non-halogen flame-retardant cross-linked polyolefin insulated wire having a sheath made of a non-halogen polyolefin composition including a silanol catalyst (C). 2. The polyolefin resin (A) grafted with an organic silane compound contains 1 to 5 parts of an organic unsaturated silane with respect to 100 parts by weight of a base polyolefin resin.
The non-halogen flame-retardant crosslinked polyolefin insulated wire according to claim 1, which is obtained by reacting 1 part by weight and 0.01 to 1 part by weight of a free radical generator. 3. A halogen-free flame-retardant compound (B) comprising a polyethylene-based resin (A) grafted with an organosilane compound, ammonium polyphosphate, a phenol novolac resin, and expansive graphite with 80 mesh-on of 70% or less. ) A halogen-free flame-retardant crosslinked polyolefin insulated wire having a sheath made of a halogen-free polyolefin composition comprising 30 to 80 parts by weight and a silanol catalyst (C).