JP3460666B2 - Flame retardant polyolefin resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flame-retardant polyolefin resin composition which is extruded as an insulating coating or sheath for electric wires and cables.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of safety and health,
Non-halogen flame-retardant resin compositions, which have low smoke generation in a fire and do not generate harmful gases such as hydrogen halide, have come to be used as insulating coatings or sheath materials for cables. These resin compositions generally use a metal hydrate such as magnesium hydroxide or aluminum hydroxide as a flame retardant and red phosphorus or a phosphoric acid compound as a flame retardant aid. However, these resin compositions have the following problems.

1) The flame-retardant effect of the metal hydrate itself is not so large as compared with the halogen-based flame retardant, and it is necessary to increase the filling amount in order to impart sufficient flame retardancy. When the filling amount of the metal hydrate is increased, the compatibility between the metal hydrate and the polymer molecule is decreased and the shear viscosity of the resin composition is increased, so that the torque during extrusion molding is increased and the appearance of the molded product is increased. It is necessary to reduce the molding linear velocity due to roughening. 2) Further, when the filling amount of the metal hydrate is increased, the hardness and bending elastic modulus of the resin composition increase, and the wire cable becomes hard and difficult to handle. The reason for this is that, in addition to the hardness of the metal hydrate itself, the amorphous part of the base polymer is preferentially filled with the metal hydrate. It is thought to be due to the decrease.

3) Since the metal hydrate or the inorganic filler and the polyolefin resin are inherently incompatible with each other, the resin composition containing them has a low extensional viscosity when melted. For this reason, it becomes impossible to endure the extensional deformation that occurs during extrusion, and the surface of the molded product becomes rough when the processing linear velocity during extrusion increases. 4) It is better to narrow the molecular weight distribution of the polyolefin resin to be used in order to achieve a large amount of metal hydrate or inorganic filler and mechanical properties of the final product (electric wire coating), but the extrusion torque is high and the processing line is high. I can't increase speed. A resin having a narrow molecular weight distribution does not lower the shear viscosity even when the shear rate increases, and thus increases the extrusion torque during high-speed extrusion and reduces the processability.

5) On the other hand, if the filling amount of the metal hydrate is reduced in order to improve the extrusion processability and the flexibility, the flame retardancy of the resin composition decreases. Especially when based on a polyolefin resin containing no polar monomer, the carbonization rate is slow,
Since heat generation and combustion continue for a long time, the flame retardancy is extremely reduced.

6) Therefore, in order to maintain the flame retardancy even if the filling amount of the metal hydrate is reduced, a flame retardant aid such as red phosphorus may be added. The resin composition is colored reddish brown, and changes the color tone of white or the coating of colored objects. 7) In addition, since magnesium hydroxide has a higher release temperature of water of crystallization than aluminum hydroxide, it is possible to suppress the foaming phenomenon due to the release of water even when the temperature rises at a high shear rate, and use brucite ore as a raw material. Crushed products are resistant to C
O ₂ whitening property (because magnesium hydroxide reacts with moisture and carbon dioxide in the air to form magnesium carbonate,
Although white spots may be formed on the surface of the molded product, it is preferably used because of its excellent resistance to this phenomenon.

[Problems to be Solved by the Invention]

The present invention does not contain halogen or phosphorus and is excellent in extrudability while maintaining high flame retardancy. The surface of the extruded product during extruding is good, and coloring is difficult during compounding or extruding. Another object is to obtain a flame-retardant polyolefin resin composition having excellent whitening resistance.

[Means for Solving the Problems]

In consideration of the above-mentioned various problems, the inventors of the present invention have made extensive studies as to a measure having both high flame retardancy and good extrusion processability, and as a result, have found the following solution and found the present invention. Has been completed. The following physical properties relating to the materials constituting the present invention are values measured based on the following standards and conditions. a) Molecular weight distribution (MWD): Weight average molecular weight (Mw) and number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) method, and Mw / Mn
I asked more. b) MFR: temperature 190 based on JIS K7210
Die diameter 2.095m under conditions of ℃ and load 2.16kg
It was measured in m. c) Die swell ratio: Measured at a temperature of 200 ° C. based on the method shown in JIS K7199. The die used had a capillary length (l) to diameter (d) ratio (l / d) of 4. d) Viscosity: Measured at a temperature of 25 ° C. using a Ubbelohde viscometer according to ASTM D-445-46T.

In the present invention, the blending amount of (A-1) linear low density polyethylene obtained by copolymerizing ethylene and α-olefin is 30 to 80% by weight, and (A-2) ethylene-vinyl acetate copolymer 100 parts by weight of a polyolefin mixture containing 20 to 70% by weight of at least one compound selected from the group consisting of a polymer, an ethylene-ethyl acrylate copolymer or an ethylene-methyl acrylate copolymer, (B-1)
A flame-retardant polyolefin resin composition containing 50 to 140 parts by weight of a metal hydrate and 2 to 10 parts by weight of (C) a straight polysiloxane , which is (B-1) metal hydrate. As a product, the average particle diameter (D50) is 1.0 to 7.0.
Provided is a flame-retardant polyolefin resin composition characterized by using magnesium hydroxide made of brucite ore having a Mg (OH) ₂ content of 85 to 95% by weight as a raw material. (Claim 1)

The resin composition comprises (A-1) and (A-
Using the combination of 2) as a base polymer, (B-1)
Addition of (C) and (C) combine the good mechanical properties of (A-1) with the extrudability and flexibility of (A-2) to provide a flame retardant (B-1) and a flame retardant aid (C). High flame retardancy is exhibited by the synergistic action of () with (A-2). Also difficult
The fuel aid (C) is used for resin processing with the flame retardant (B-1).
Suppresses coloring.

Further, in the present invention, as (B-1), the average particle diameter (D50) is 1.0 to 7.0 μm, and Mg (OH)
Magnesium hydroxide made from brucite ore having a content of ₂ of 85 to 95% by weight is used. As (B-1), from the viewpoint of preventing a foaming phenomenon during extrusion, magnesium hydroxide having a high dehydration reaction temperature is preferable, and the average particle diameter of magnesium hydroxide is within the above range of 1.0 to 7.0 μm. By setting to, it is possible to reduce the degree of surface roughness during extrusion. Further, as magnesium hydroxide, the average particle diameter (D50) is 1.0 to
The CO ₂ whitening resistance phenomenon can be reduced by using brucite ore as the raw material having a Mg (OH) ₂ content of 7.0 μm and a Mg (OH) ₂ content of 85 to 95% by weight.

In order to maintain mechanical properties when adding a metal hydrate or an inorganic filler, it is preferable that (A-1) is contained in the polyolefin resin in an amount of 30% by weight or more, but if it exceeds 80% by weight. Extrudability deteriorates. In order to improve the extrusion processability, (A-2) and / or (A-3) is
It is preferable that the polyolefin resin is contained in an amount of 20% by weight or more, but if it exceeds 70% by weight, the mechanical properties of the resin composition deteriorate.

The present invention also provides the above (A-1) and (A-
(B-1) metal hydrate, (B-2) inorganic filler and (C) strain in the polyolefin resin mixture containing 2).
Provided is a flame-retardant polyolefin resin composition, which is characterized by containing a salt- based polysiloxane. (Claim 2) By coexisting (B-2) with (B-1), the resin component is diluted and the flame retardant effect can be enhanced.

In the present invention, the (A-1) ethylene-α-olefin copolymer has a
It is at least one selected from the group consisting of 1, hexene-1, 4-methylpentene-1 or octene-1. (Claim 3) LLDPE containing these α-olefins as comonomer
Has a particularly good balance of strength and flexibility, and when it is combined with (A-2) and mixed with (B-1) and (C) and / or (B-2), it improves the processability of mixing and extrusion. A resin composition having excellent mechanical properties and flame retardancy as well as excellent properties is formed.

In the present invention, the density of (A-1) is 0.880.
To 0.920, the molecular weight distribution is 3.0 to 6.0, and the MFR is 0.5 to 2.0. (Claim 4) As (A-1), as described above, when a polymer having a low density in the polyolefin resin, a relatively wide molecular weight distribution, and a high molecular weight component is selected, a resin composition can be obtained. On the other hand, when filled with a metal hydrate, an inorganic filler, or the like, the flexibility is not lost, the extrudability is good, and the mechanical properties required for coating the electric wire can be provided.

The present invention further relates to the como used in (A-2).
The nomer is vinyl acetate (hereinafter abbreviated as VA), ethyl acrylate (hereinafter abbreviated as EA) or methyl acrylate (hereinafter abbreviated as MA), and the addition amount thereof is
5-25% by weight, MFR of the resulting copolymer is 0.5-
It is characterized by using a material having a 5.0 and a die swell ratio in the range of 1.2 to 2.5. (Claim 5) (A-
By adjusting the amount of the polar comonomer contained in 2) to 10% or more, flexibility and flame retardancy can be improved. When the amount of polar comonomer increases, the compatibility with (A-1) decreases, so it is preferable to suppress it to 25% by weight or less. Further, by setting the MFR and die swell ratio of (A-2) within the above ranges, excellent extrudability can be maintained.

The present invention is also characterized in that (A-2) is EVA. (Claim 6) EVA has a higher carbonization rate than EEA and EMA and is suitable for improving flame retardancy. Moreover, it is inexpensive and easily available, and is preferable from the viewpoint of economy.

Further, the present invention is characterized in that (B-2) is (heavy) calcium carbonate having an average particle diameter (D50) of 1.0 to 7.0 μm. (Claim 7) By setting the average particle diameter of (B-2) within the above range, the degree of surface roughness during extrusion can be suppressed to a low level.

Next, in the present invention, (C) has a viscosity of 600.
It is characterized by being a straight polysiloxane in the range of 0 to 25,000 cps. (Claim 8) When the viscosity of (C) is less than 6000 cps, bleeding easily occurs from the resin composition, which is not preferable. On the other hand, 25
If it is higher than 000 cps, it becomes difficult to disperse the materials at the time of mixing and the quality of the compound is deteriorated, which is not preferable. The addition amount of (C) is preferably 2 parts by weight or more in order to contribute to the improvement of the flame retardancy, but if it exceeds 10 parts by weight, the improvement of the flame retardance will reach a peak and the cost will increase, which is not preferable. .

Further, the present invention is characterized in that (C) is dimethylpolysiloxane. (Claim 9) Dimethylpolysiloxane has a higher flame retardancy-improving effect than other straight polysiloxanes, and suppresses reddish brown discoloration of a resin composition which occurs when magnesium hydroxide derived from brucite ore is added. There is also a unique effect of doing.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Among the polyolefin mixtures constituting the flame-retardant polyolefin resin composition of the present invention, (A-1)
LLDPE formed by copolymerizing ethylene and α-olefin
As a single site catalyst represented by a metallocene catalyst, or a so-called Ziegler type catalyst (titanium type,
It is possible to use a multi-site catalyst typified by a chromium-based catalyst or the like, which is polymerized by any of them. Butene-
LLDP having 1, -hexene-1,4-methylpentene-1 or octene-1 as an α-olefin comonomer
E is preferable, but when considering the flexibility of the resin composition,
Hexene-1,4-methylpentene-1, octene-1
It is particularly preferable to use a bulky comonomer such as, since the lamella is thin and contributes to flexibility. The density of the polymer used in (A-1) is preferably in the range of 0.880 to 0.920, but in view of oil resistance, a low density polymer is disadvantageous, and a polymer having a density less than the above range causes poor performance. There is a high risk of causing it. For example, when a resin having a density of less than 0.880 is used, the oil resistance performance required for the wire coating material specified in JIS C3005 cannot be satisfied. If the density exceeds 0.920, it becomes hard when a metal hydrate or the like is added, and the flexibility becomes poor when the wire is used as an insulating coating. The molecular weight distribution (MWD) of the polymer is monodisperse (MWD)
= 1), the material strength tends to increase, which is effective for increasing the filling amount of the filler, but the decrease in shear viscosity at high shear is small, the extrusion torque increases, and the workability deteriorates. On the other hand, when the molecular weight distribution becomes wider, the result is that more low molecular weight components are contained, resulting in high efficiency of shear viscosity reduction at high shear and contributing to reduction of screw torque during high speed extrusion, thus improving extrusion processability, but conversely Strength is reduced. Therefore (A
Regarding the molecular weight distribution of the polymer used in -1), 3.0 to 6.0 when considering the balance between processability and material strength.
The optimum range is. The MFR of a polymer is an indicator of average molecular weight. When the MFR is small, the amount of high molecular weight components is large, which makes extrusion difficult. On the other hand, when the MFR is large, the amount of low molecular weight component becomes excessive and the material strength is lowered. Therefore,
To obtain the strength characteristics specified in "Technical Standards for Electrical Appliances and Handling Details", the MFR of the polymer used in (A-1)
Is preferably in the range of 0.5 to 2.0. Examples of the polymer (A-1) which meets the above-mentioned density, molecular weight distribution and MFR conditions include butene-1 and hexene-
Resin polymerized by gas phase method with 1 as comonomer, 4
Examples thereof include a resin polymerized by a solution polymerization method using methylpentene-1 or octene-1 as a comonomer, and a resin polymerized by a high pressure ionic polymerization method using butene-1 and hexene-1 as comonomers.

Next, as (A-2), EVA, EE
A and EMA can be used, but V is a polar comonomer
A, EA, the addition amount of MA is 5 to 25 wt%, MFR is 0.5 to 5.0, a die swell ratio is particularly preferable polymer in the range of 1.2 to 2.5. Copolymers having these polar groups have a smaller total calorific value in a filler-filled system than ethylene homopolymers and are suitable for use in flame-retardant materials. Particularly, in consideration of material characteristics (strength, etc.) at the time of use, those having an average molecular weight that brings the above MFR range are preferable. If the content of the polar group is too low, the calorific value reducing effect is reduced, and if it is too high, the compatibility with the blending partner LLDPE is reduced and the material properties are reduced. Further, since the polar group lowers the crystallinity of the polyethylene skeleton, the higher the content, the more the flexibility can be improved, but the content too high is not preferable because it deteriorates the properties as described above.

In the polyolefin resin mixture of the present invention, the ratio PR (polarity ratio) of the polar comonomer necessary for exerting the flame retardant effect to all the resin components is preferably 7 to 12% by weight, so that (A-2) The ratio of (A-1) and (A-2) may be determined in consideration of the polar monomer content.

(A-2) has a long chain branching and exerts an effect of reducing the shear viscosity at high shear. Therefore, it is possible to suppress the torque increase when the extruder screw is rotated at high speed during high-speed extrusion. Further, since it has a long chain branch, the tension at the time of melting (melt tension) is high, and it is effective in reducing the rough skin phenomenon that occurs immediately after passing through the extrusion die. In the extrusion of the filler-filled material, this rough skin phenomenon often becomes a problem because the melt-tension of the filler-filled material is low, and the effect of a long-chain branched polymer having a high melt tension is required as a countermeasure. However, if the degree of branching is low, the melt tension is also low and it is not effective, so the degree of branching must be within the specified range. The die swell ratio is an index for conveniently evaluating the number of long chain branches. The larger the number of branches, the larger the die swell ratio. A resin having a large number of long chain branches has a high frequency of entanglement of molecules with each other, resulting in a resin material having a high melt tension.

As the (B-1) metal hydrate used in the present invention, magnesium hydroxide is suitable, and its average particle diameter (D50) is 1.0 to 7.0 μm, and Mg (OH) ₂ of It is preferable to use a brucite ore having a content of 85 to 95% by weight as a raw material. As (B-1), from the viewpoint of preventing foaming phenomenon during extrusion, magnesium hydroxide having a high dehydration reaction temperature is preferable, but magnesium hydroxide reacts with moisture and carbon dioxide in the air to form magnesium carbonate. By doing so, white spots may be formed on the surface of the molded product. However, the average particle diameter (D50) is 1.0 to 7.
If magnesium hydroxide made from brucite ore having a Mg (OH) ₂ content of 0 to 5 μm and a Mg (OH) ₂ content of 85 to 95% by weight is used, the effect of suppressing the formation of white spots (so-called CO ₂ whitening resistance) can be obtained. This is a major feature of the present invention. The content of Mg (OH) ₂ is too large at 95% or more, and the average particle diameter (D50) is 1.0 μm.
If it is too small, the problem of white spots tends to occur. M
If the content of g (OH) ₂ is too small, i.e. 85% or less, the effect of flame retardancy deteriorates. The average particle diameter (D50) is 7.
If it is too large, such as 0 μm or more, a problem of surface roughness occurs during extrusion.

As the inorganic filler (B-2) used in the present invention, talc, clay, magnesium oxide, magnesium carbonate, calcium carbonate and the like used in resin molding materials can be used. Of these, calcium carbonate is particularly preferable because it is easy to handle because secondary aggregation hardly occurs. It is considered that calcium carbonate plays a role of improving the dispersibility of the metal hydrate when blended with the metal hydrate (B-1) which easily causes secondary aggregation.

The straight polysiloxane of (C) is
When used in combination with (B-1) or (B-2), since the flame retardant effect is enhanced, the addition amount of the above-mentioned inorganic filler can be reduced by the addition thereof, and the extrusion processability is improved. Work to your advantage. Is the use in the present invention (C), stress
Soot-based polysiloxanes are suitable. The present inventors have found that methyl hydrogen polysiloxane be sampled <br/> rate system, the flame retardancy effect of dimethylpolysiloxane high. In addition, it has also been found that the straight polysiloxane has a unique effect of suppressing the reddish brown discoloration of the resin composition that occurs when magnesium hydroxide derived from brucite ore is added. Among the straight polysiloxanes, dimethylpolysiloxane has the highest flame retardancy improving effect and is particularly preferable. The stray
Doo-based polysiloxane, viscosity 6000~25000c
It is preferably in the range of ps. The viscosity is 600
Below 0 cps, bleeding from the material occurs, which is not preferable. On the other hand, if it exceeds 25,000 cps, it becomes difficult to disperse the material when mixing the materials, which deteriorates the quality of the compound.

The flame-retardant resin composition of the present invention contains an antioxidant, a copper damage inhibitor, an ultraviolet absorber, an ultraviolet masking agent, carbon and other coloring pigments, etc., as long as the characteristics thereof are not impaired.
You may mix | blend the additive generally used for resin molding material. In particular, DL-α-tocopherol (vitamin E) is used as an antioxidant, and an organic skeleton-based hindered amine-based UV absorber is used as a UV absorber, which has no adverse effects on the human body or the environment and has no problem in food hygiene. Therefore, it is preferable.
In particular, DL-α-tocopherol is effective at a low addition amount and has a function of suppressing the attack of oxygen radicals on the carbon skeleton itself. Therefore, a large amount of conventional antioxidants (bisphenol, etc.) or an ultraviolet absorber is added. It is possible to suppress the cost increase of the resin composition due to the above.

The resin composition of the present invention is melt-mixed in a compounding equipment such as a commonly used twin-screw kneading extruder, kneading kneader, kneading roll, etc., and granulated into a suitable shape if necessary. Can be manufactured. Insulation of the electric wire / cable or coating of the sheath or the like with the pellets thus produced can be carried out using an extruder or the like according to a usual method. Further, as for (C), as described above, even when added in the same manner as other additives when mixing the resin and the filler such as metal hydrate or inorganic filler, the surface treatment agent to the filler in advance. Even if the filler is applied as above and used at the time of mixing, it is similarly effective in improving workability during extrusion.

The flame-retardant resin composition according to the present invention was measured and evaluated according to the following standards and conditions. i) Tensile property: A press sheet having a thickness of 1 mm is prepared from the resin composition, and the method is defined in JIS C3005.
JIS Kai No. 3 dumbbell is punched out and the pulling speed is 20 at room temperature.
Tensile strength and breaking elongation were measured by pulling at 0 mm / min.
For use as a cable insulating material or sheath material, the tensile strength and the breaking elongation are preferably 10 MPa or more and 350% or more, respectively.

Ii) Flexural modulus: A standard test piece was prepared by the method specified in JIS K7171, and the test speed was 50 m.
It was measured and evaluated at m / min. The flexural modulus serves as an index indicating the flexibility of the insulating material or the sheath material, and is preferably 350 MPa or less in consideration of the ease of handling the cable.

Iii) Shear viscosity: Based on JIS K7199, the set temperature is 200 ° C., the die has an orifice diameter of 0.5 mmφ, the land length is 8 mm, and the apparent shear viscosity is measured at a shear rate of 3000 / sec using a capillary rheometer. Lavinovich correction was performed to calculate the true viscosity. A resin material having a lower shear viscosity at a high shear rate can suppress an increase in extrusion torque during high-speed extrusion, which is advantageous for extrusion processing.
-It is preferable to take a value of sec or less.

Iv) Extrusion appearance: The molded product extruded using the capillary rheometer in the shear viscosity measurement in the preceding paragraph was measured and evaluated for the average surface roughness based on the method specified in JIS B0601. The average surface roughness Ra of the cable material is preferably 5 μm or less.

V) Oxygen index: Measured according to JIS K7201. The index of flame retardancy is preferably 27 or more.

Vi) Electric wire combustion test: Using a 150 mmφ extruder, a stranded wire conductor having an outer diameter of 6 mm was sheath-coated with a resin composition in a thickness of 1.5 mm at a set temperature of 170 ° C., and an outer diameter of 9.4.
A mm cable was prepared. About this cable, J
A combustion test was conducted according to the method specified in ISC3005. In the evaluation, in accordance with the technical standards and handling details of electrical equipment, the case of self-extinguishing within 60 seconds was represented by O, and the other cases were represented by X.

Specific embodiments of the present invention will be described below with reference to examples and comparative examples. Example 1 LLDPE-1 and EVA-1 shown in Table 1 had a viscosity of 2
5000 cps dimethylpolysiloxane, magnesium hydroxide (average particle size 3.5 μm, made from brucite ore having an Mg (OH) ₂ content of 85 to 95% by weight), and calcium carbonate (average particle size) 1.2
μm) in a weight ratio shown in Table 2 to obtain a flame-retardant polyolefin resin composition. This composition was heated at 180 ° C for 1
A press sheet was manufactured by a 0-ton press by the method described in the section of the electric wire combustion test, and the above-mentioned characteristics were measured. The results are shown in Table 2.

Examples 2 to 3 and Comparative Examples 1 to 3 A polyolefin resin composition was obtained in the same manner as in Example 1 except that the polyolefin resins shown in Table 1 were used and the type of compounding material and the number of parts were changed to Table 2. It was A press sheet and a cable were produced from this composition, and the above properties were measured. The results are shown in Table 2.

[0038]

[Table 1]

[0039]

[Table 2]

In the flame-retardant resin compositions of Examples 1 to 3, all of the above-mentioned properties are in the preferred range, and the materials defined by the present invention are mechanical properties, extrusion processability, It shows that the flame retardance is well balanced. In Comparative Example 1, (A-2) was added to the polyolefin resin mixture.
However, as compared with Example 4, even though an equivalent amount of the flame retardant and the flame retardant aid are blended,
Fails the electric wire combustion test. The reason for this is that in Example 4, (A-2) having a polar group is effective in reducing the total calorific value during combustion in the coexistence of the flame retardant and the flame retardant auxiliary. It is considered that Comparative Example 1 not containing (A-2) does not have this effect. Comparative Example 1
The material has a high flexural modulus and lacks flexibility, but it reduces the crystallinity of the polyethylene skeleton and improves flexibility (A-
This is because 2) is not included. Furthermore, the material of Comparative Example 1 is
High shear viscosity during melting and extruded appearance The surface has a large average roughness value, but does not contain (A-2) with long chain branching.
Since only LDPE is the base polymer, the shear viscosity at the time of high shear becomes large, and the tension holding effect at the time of melting due to long chain branching is small, so it is considered that the rough skin phenomenon was likely to occur immediately after passing through the extrusion die. .

Since the resin composition of Comparative Example 2 does not contain (B-1), it has a low oxygen index and does not pass the electric wire combustion test. Comparative Example 3 does not contain the flame retardant aid (C), and thus has a low oxygen index and does not pass the electric wire combustion test. The resin composition of Example 3 is excellent in flame retardancy and extrusion processability, but the VA content of EVA contained as (A-2) is as high as 30% by weight, so that the tensile strength is slightly lowered.

[0042]

EFFECTS OF THE INVENTION The flame-retardant polyolefin resin composition of the present invention has a high degree of flame-retardant property even if it does not contain halogen or phosphorus, and is excellent in extrusion processability, so that problems such as surface roughness during high-speed extrusion hardly occur. When used as an insulator or sheath for electric wires / cables, it is possible to manufacture an electric wire / cable that has low smoke generation in a fire and does not generate harmful gas such as hydrogen halide at low cost. Further, since the flame-retardant polyolefin resin composition of the present invention is less likely to be colored during mixing of materials or during extrusion, it is a white or colored material and is suitable for electric wires and can be used for a wider range of electric wires and cables. Further, the flame-retardant polyolefin resin composition of the present invention has, as magnesium hydroxide, an average particle diameter (D50) of 1.0 to 7.0 μm and a Mg (OH) ₂ content of 85 to 85 μm.
Magnesium hydroxide using 95% by weight of brucite ore as a raw material is used, and it has an effect of suppressing the formation of white spots (so-called CO ₂ whitening resistance) and is excellent in environmental resistance.

Continuation of the front page (56) References JP 62-104853 (JP, A) JP 6-200091 (JP, A) JP 61-228046 (JP, A) JP 2-255843 (JP , A) JP-A-10-7913 (JP, A) JP-A-8-295764 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 1/00-101/16 C08K 3/00-13/08

Claims (9)

(57) [Claims] 1. The amount of linear low-density polyethylene (A-1) obtained by copolymerizing ethylene and α-olefin is 30.
To 80% by weight, at least one compound selected from the group consisting of (A-2) ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer or ethylene-methyl acrylate copolymer is 20- Flame-retardant polyolefin resin composition containing (B-1) 50 to 140 parts by weight of a metal hydrate and (C) 2 to 10 parts by weight of a straight polysiloxane in 100 parts by weight of a 70% by weight polyolefin mixture. And as the (B-1) metal hydrate,
The average particle diameter (D50) is 1.0 to 7.0 μm, and M
A flame-retardant polyolefin resin composition characterized by using magnesium hydroxide made from brucite ore having a content of g (OH) ₂ of 85 to 95% by weight. 2. The blending amount of linear low-density polyethylene (A-1) obtained by copolymerizing ethylene and α-olefin is 30.
To 80% by weight, at least one compound selected from the group consisting of (A-2) ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer or ethylene-methyl acrylate copolymer is 20- 100 parts by weight of a 70% by weight polyolefin mixture, 50 to 140 parts by weight of (B-1) metal hydrate, and (B-2) inorganic fillers 10 to 6
0 parts by weight and (C) straight polysiloxane 2 to
A flame-retardant polyolefin resin composition for the additional inclusion of 10 parts by weight, (B-1) as a metal hydrate, by its average particle diameter (D50) 1.0~7.0μm, Mg (O
H) A flame-retardant polyolefin resin composition characterized by using magnesium hydroxide made from brucite ore having a content of ₂ to 85 to 95% by weight. 3. The (A-1) α-olefin in the linear low-density polyethylene obtained by copolymerizing ethylene and α-olefin is butene-1, hexene-1, 4-methylpentene-1 or octene-. At least Tsudea Ru請 Motomeko 1 or flame-retardant polyolefin resin composition according to claim 2 selected from the group consisting of 1. 4. The density of (A-1) is 0.880 to 0.92.
0, molecular weight distribution of 3.0 to 6.0, MFR of 0.5 to
Range near 2.0 Ru請 Motomeko 1 or flame-retardant polyolefin resin composition according to claim 2. 5. The comonomer used in (A-2) is vinyl acetate, ethyl acrylate or methyl acrylate, the addition amount thereof is 5 to 25% by weight, and the MFR of the resulting copolymer is 0.5. ~ 5.0, die swell ratio 1.2 ~
To use those in the range of 2.5 請 Motomeko 1 or flame-retardant polyolefin resin composition according to claim 2. 6. The flame-retardant polyolefin resin composition according to claim 1 or 2, wherein (A-2) is an ethylene-vinyl acetate copolymer. 7. (B-2) has an average particle diameter (D50) of 1.0.
Ru calcium carbonate der of ~7.0μm 請 Motomeko 1 or flame-retardant polyolefin resin composition according to claim 2. 8. The viscosity of (C) is 6000 to 25000 cp.
s area by near the 請 Motomeko 1 or flame-retardant polyolefin resin composition according to claim 2. 9. (C) is dimethylpolysiloxane der Ru請 <br/> Motomeko 1 or flame-retardant polyolefin resin composition according to claim 2.