JP2011137184A - Blooming restraining method for flame-retardant resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant resin composition capable of restraining blooming of a surface treating agent, and having an excellent fixed flame retardancy and mechanical characteristic, water-proofness, and carbon dioxide whitening resistance, in the flame-retardant resin composition using, as a flame retardant, magnesium hydroxide treated with a carboxylate as the surface treating agent, an extrusion molding thereof, and a blooming restraining method for the flame-retardant resin composition capable of obtaining an electric wire/cable having a coating layer extrusion-molded therewith. <P>SOLUTION: This flame-retardant resin composition is blended with 35-110 pts.wt. of the magnesium hydroxide (B) surface-treated with one or more of the surface treating agent (a) selected from the group of higher fatty acid polyhydric alcohol esters, dicarboxylic acid monoesters and higher fatty acid alkyl esters, per 100 pts.wt. of resin (A), and this blooming restraining method for the flame-retardant resin composition restrains the surface treating agent from blooming out of the flame-retardant resin composition, by blending further 10-55 pts.wt. of calcium carbonate (C) to the flame-retardant resin composition. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for suppressing blooming of a flame retardant resin composition, and more specifically, in a flame retardant resin composition using magnesium hydroxide treated with a carboxylic acid ester as a surface treatment agent as a flame retardant, the surface treatment. A flame retardant resin composition that suppresses blooming of the agent and has excellent and constant flame retardancy and mechanical properties, and water resistance and carbon dioxide whitening resistance, an extruded product thereof, and a coating layer obtained by extrusion molding the same The present invention relates to a blooming suppressing method for a flame retardant resin composition capable of obtaining an electric wire / cable.

Conventionally, as flame retardants for resins and rubbers, those containing a combination of halogen-containing compounds and phosphorus-containing compounds have been used. Many uses of magnesium have been proposed.
However, if magnesium hydroxide is not compounded in a relatively large amount, flame retardancy cannot be obtained, and the compatibility between the resin such as olefin resin and magnesium hydroxide is poor, and the resulting flame retardant resin composition There is also a problem with dispersibility of magnesium hydroxide and water resistance, and when magnesium hydroxide reacts with water and carbon dioxide in the air, there is a problem of whitening of carbon dioxide that turns white into basic magnesium carbonate. And when this flame-retardant resin composition was used as a coating layer of an electric wire / cable as an extrusion-molded product, there was a problem that the electrical characteristics were significantly lowered.

For this purpose, magnesium hydroxide is treated with a surface treatment agent. Examples of the surface treatment agent include higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, waxes or modified products thereof, curable resins, silane coupling agents, titanate coupling agents, and the like (Patent Documents 1 and 2). 3).
Patent Document 4 discloses surface-treated magnesium hydroxide surface-treated with a polyhydric alcohol higher fatty acid ester (or higher fatty acid polyhydric alcohol ester) as a surface treating agent, and flame retardant comprising this and a resin or rubber. It is described that the water-soluble resin composition has mechanical properties, water resistance, and carbon dioxide whitening resistance, and the balance of these can be adjusted.
Furthermore, Patent Document 5 describes that the use of a dicarboxylic acid monoester as a surface treatment agent for magnesium hydroxide has water resistance and can impart flame retardancy.
Further, Patent Document 6 overcomes the contradictory performance of flame retardancy and carbon dioxide whitening resistance, which is composed of a polyolefin resin (functional group-containing olefin polymer), calcium carbonate and an inorganic flame retardant. Disclosed is a flame retardant resin composition with improved whitening properties. Among them, magnesium hydroxide surface-treated with a fatty acid ester is magnesium hydroxide surface-treated with a fatty acid ester when it is easy to cut. The excellent characteristics of are described.
Further, Patent Document 7 discloses a flame retardant resin composition which is composed of a thermoplastic resin, metal hydroxide, acetate or calcium carbonate, has no harmful combustion gas, and has excellent flame retardancy and mechanical strength. Is also disclosed.

  In the prior art according to these prior documents, magnesium hydroxide surface-treated with a carboxylic acid ester has characteristics such as excellent water resistance, carbon dioxide whitening resistance, and easy cutting properties, but is a surface treatment agent. Carboxylic acid ester may exude to the surface of the molded product after molding, so-called blooming may occur. When used in the environment, there is a possibility that the carboxylic acid ester may float in the environment, and there is a concern that the quality of the semiconductor product may be adversely affected.

Japanese Patent Laid-Open No. 60-100302 JP-A-5-17692 JP 7-161230 A JP 2005-54038 A JP 2005-179615 A JP 2005-213480 A JP 2000-211981

  An object of the present invention is to provide a flame retardant resin having excellent water resistance and carbon dioxide whitening resistance, which is composed of a resin and magnesium hydroxide surface-treated with a carboxylic acid ester in view of the above-mentioned problems of the prior art. In the composition, it is possible to suppress blooming of the carboxylic acid ester which is a surface treatment agent while maintaining certain flame retardancy and mechanical properties. This flame retardant resin composition, its extrusion-molded product, and its extrusion An object of the present invention is to provide a method for suppressing blooming of a flame retardant resin composition that can obtain an electric wire / cable having a coating layer obtained by molding.

  In order to solve the above problems, the present inventors have examined various additives that suppress blooming while ensuring water resistance, carbon dioxide whitening resistance, certain flame retardancy, and mechanical properties. When magnesium hydroxide and calcium carbonate surface-treated with carboxylic acid esters are blended in a specific ratio, blooming is suppressed, and water resistance, carbon dioxide whitening resistance, certain flame resistance and mechanical properties are ensured. The present invention has been completed by finding out what can be done.

  That is, according to 1st invention of this invention, 1 type (s) or 2 or more types chosen from higher fatty acid polyhydric alcohol ester, dicarboxylic acid monoester, or higher fatty acid alkyl ester with respect to 100 weight part of resin (A). By further adding 10 to 55 parts by weight of calcium carbonate (C) to the flame retardant resin composition containing 35 to 110 parts by weight of magnesium hydroxide (B) surface-treated with the surface treatment agent (a), There is provided a method for suppressing blooming of a flame retardant resin composition, wherein the blooming of the surface treatment agent is suppressed from the flame retardant resin composition.

  According to a second invention of the present invention, in the first invention, the amount of surface treatment with the surface treating agent (a) is 0.5 to 5.0% by mass. An object blooming suppression method is provided.

According to the third invention of the present invention, there is provided a blooming suppressing method for a flame retardant resin composition, wherein the resin (A) is an ethylene resin in the first or second invention. The
Further, according to the fourth invention of the present invention, in the third invention, the ethylene-based resin comprises a linear low density ethylene-α-olefin copolymer, an ethylene-vinyl acetate copolymer, and an ethylene-acrylic acid. There is provided a method for suppressing blooming of a flame retardant resin composition, which is at least one selected from the group consisting of ethyl copolymers.

  As described above, the present invention provides a flame retardant resin composition excellent in water resistance and carbon dioxide whitening resistance, comprising a resin and magnesium hydroxide surface-treated with a specific carboxylic acid ester. It is a method of suppressing blooming of the flame retardant resin composition by blending. The carboxylic acid ester as the surface treatment agent has excellent compatibility between the resin and magnesium hydroxide, and has excellent dispersibility. As a result, the resulting flame retardant resin composition also has mechanical properties. In addition to being excellent and excellent in extrusion moldability, calcium carbonate is further blended so as not to impair the above-mentioned excellent effects, and the mechanism of action is not clear, When the calcium carbonate keeps the surface treatment agent in the resin, the flame retardant resin composition has an excellent effect of suppressing blooming and leaching of the surface treatment agent on the surface of the molded product. Thereby, the extruded product of the flame retardant resin composition and the electric wire / cable having the coating layer obtained by extrusion molding have excellent performance.

  Hereinafter, the blooming suppression method of the flame retardant resin composition of the present invention will be described in detail for each item.

1. Resin (A)
Examples of the resin (A) used in the present invention include thermoplastic resins such as polyolefin resins, methacrylic resins, acrylic resins, vinyl acetate resins, and saturated polyester resins.
Among these, an olefin resin having nonpolarity or weak polarity can be used favorably because a more significant blooming suppressing effect is obtained.

Examples of olefin resins include ethylene resins and propylene resins. In the present invention, ethylene resins that have a proven record as an insulating coating layer for electric wires and cables can be used as particularly suitable resins.
Examples of the ethylene resin include high-pressure polyethylene, ethylene-α-olefin (carbon number 2 to 12) copolymer, ethylene-α, β-unsaturated carboxylic acid alkyl ester copolymer, and ethylene-carboxylic acid vinyl ester copolymer. Specifically, high pressure method low density polyethylene, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-butyl methacrylate copolymer Examples thereof include a copolymer, an ethylene-vinyl acetate copolymer, an ethylene-butene-1 copolymer, an ethylene-hexene-1 copolymer, and an ethylene-octene-1 copolymer.

In the present invention, an ethylene-ethyl acrylate copolymer or ethylene-acetic acid having a melt mass flow rate of 0.05 to 50 g / 10 min and a comonomer content of 5 to 40% by weight is compatible with magnesium hydroxide. It is preferable to use a vinyl copolymer and a linear low-density ethylene-α-olefin copolymer having a melt mass flow rate of 0.05 to 50 g / 10 min and a density of 0.86 to 0.92 g / cm ^3. it can.

  Specific examples of the propylene-based resin include a propylene homopolymer, an ethylene-propylene copolymer, an ethylene-butene-1 copolymer, and an ethylene-propylene-butene-1 terpolymer.

Moreover, what is called rubber | gum is also included as resin (A), and this can also be used. This includes ethylene-propylene rubber, ethylene-propylene-diene rubber, acrylic rubber, styrene-ethylene-propylene-styrene block copolymer, styrene-ethylene-butadiene-styrene block copolymer, styrene-ethylene-styrene block copolymer Examples include coalescence.
In addition, resin can be used 1 type or in combination of 2 or more types.

2. Magnesium hydroxide (B) surface-treated with the surface treatment agent (a) (hereinafter also simply referred to as surface-treated magnesium hydroxide)
In the present invention, the surface-treated magnesium hydroxide (B) uses a carboxylic acid ester as the surface treatment agent (a) for magnesium hydroxide. The carboxylic acid ester is one or more selected from higher fatty acid polyhydric alcohol esters, dicarboxylic acid monoesters or higher fatty acid alkyl esters.

  In the present invention, as the polyhydric alcohol constituting the higher fatty acid polyhydric alcohol ester (or polyhydric alcohol higher fatty acid ester) used, trimethylolethane (trivalent), glycerin (trivalent), trimethylolpropane (3 Value), erythritol (tetravalent), pentaerythritol (tetravalent) and the like. Among the polyhydric alcohols, glycerin is preferably used.

Examples of the higher fatty acid constituting the higher fatty acid polyhydric alcohol ester include stearic acid (C ₁₈ ), oleic acid (C ₁₈ =), linoleic acid (C ₁₈ =), palmitic acid (C ₁₆ ), and myristic acid. (C ₁₄ ), lauric acid (C ₁₂ ), capric acid (C ₁₀ ), caprylic acid (C ₈ ), behenic acid (C ₂₂ ), montanic acid (C ₂₈ ) and the like. Among the higher fatty acids, stearic acid is preferably used.
Furthermore, glycerin stearic acid ester is a suitable higher fatty acid polyhydric alcohol ester.

In the present invention, the higher fatty acid polyhydric alcohol ester does not need to have all the hydroxyl groups of the polyhydric alcohol esterified, and includes a partially esterified one. The esterification rate is expressed as% of the group that has been esterified among a plurality of hydroxyl groups of the polyhydric alcohol. For example, the esterification rate of glycerin-monostearic acid ester is 33.3%.
The esterification rate of the higher fatty acid polyhydric alcohol ester used in the present invention is desirably 40 to 90%, preferably 50 to 85%. When the esterification rate is around 50%, the mechanical properties, particularly the tensile fracture stress, of the resin composition containing the surface-treated magnesium hydroxide obtained is improved. Further, when the esterification rate increases, a slight decrease in mechanical properties is recognized, but this is not a problem in practical use. On the other hand, as the esterification rate increases, the whitening resistance of the resin composition containing the surface-treated magnesium hydroxide increases. On the other hand, in particular, when a higher fatty acid polyhydric alcohol ester having an esterification rate of less than 40% is used, the whitening resistance starts to be inferior compared to the case of magnesium hydroxide without surface coating.
Thus, by adjusting the esterification rate of the higher fatty acid polyhydric alcohol ester, it is possible to impart desired mechanical properties and whitening resistance to the resin composition containing the surface-treated magnesium hydroxide.

  The dicarboxylic acid monoester used in the present invention includes those represented by the following formula, wherein the carboxylic acid residue is a metal salt.

In the formula, R ¹ represents an aliphatic hydrocarbon group having 8 to 26 carbon atoms, R ² represents a residue obtained by removing all carboxyl groups from an aliphatic dicarboxylic acid having 3 to 8 carbon atoms, M is , Represents a hydrogen atom, an alkali metal or an alkaline earth metal, and n represents 1 when M is a hydrogen atom or an alkali metal, and 2 when M is an alkaline earth metal.

Examples of the dicarboxylic acid constituting the dicarboxylic acid monoester used in the present invention include aliphatic dicarboxylic acids having 3 to 8 carbon atoms or anhydrides thereof, malonic acid, succinic acid, maleic acid, glutaric acid, adipic acid. Specific examples include pimelic acid, suberic acid, succinic anhydride, maleic anhydride, and glutaric anhydride. Among these, succinic acid and succinic anhydride are preferable.
The aliphatic monoalcohol having 8 to 26 carbon atoms (or monool) constituting the dicarboxylic acid monoester used in the present invention includes octyl alcohol, nonyl alcohol, decyl alcohol, undenyl alcohol, lauryl alcohol, dodecyl. Examples include saturated aliphatic alcohols such as alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, stearyl alcohol, eicosyl alcohol, behenyl alcohol, and ceryl alcohol, and unsaturated aliphatic alcohols such as palmitooleyl alcohol, oleyl alcohol, and eicosonyl alcohol. Of these, saturated aliphatic alcohols having 12 to 22 carbon atoms are preferred.
Furthermore, examples of the alkali metal constituting the dicarboxylic acid monoester used in the present invention include lithium, potassium, and sodium, and examples of the alkaline earth metal include calcium, magnesium, and zinc.

The dicarboxylic acid monoester used in the present invention can be prepared, for example, by a conventional method using the above dicarboxylic acid and alcohol in the presence or absence of a solvent.
Examples of the dicarboxylic acid monoester used in the present invention include stearyl succinate, cetyl hydrogen succinate, eicosyl succinate, hydrogen lauryl malonate, sodium stearyl succinate, and bis (stearyl succinate) calcium. it can.

  In the present invention, a higher fatty acid alkyl ester can be used as a surface treatment agent for magnesium hydroxide. Examples of higher fatty acid alkyl esters include esters of higher fatty acids and aliphatic monoalcohols (monools), specifically, methyl laurate, methyl myristate, methyl palmitate, methyl stearate, methyl oleate, Methyl erucate, methyl behenate, ethyl laurate, ethyl myristate, ethyl palmitate, ethyl stearate, ethyl oleate, ethyl erucate, ethyl behenate, butyl laurate, butyl stearate, isopropyl myristate, palmitic acid Examples include isopropyl, lauryl laurate, stearyl stearate and the like.

  In the present invention, the surface treatment amount of the surface treatment agent with respect to magnesium hydroxide is desirably 0.5 to 5.0% by mass, preferably 1.0 to 4.0% by mass, and more preferably 1.5%. It is -3.5 mass%. When the surface treatment amount is less than 0.5% by mass, it becomes difficult to cover the entire surface of the magnesium hydroxide, and as a result, any of the mechanical properties and whitening resistance of the resin composition containing the surface treatment magnesium hydroxide is included. On the other hand, if it exceeds 5.0% by mass, the effect as a flame retardant for magnesium hydroxide decreases, which is not preferable.

As magnesium hydroxide used in the present invention, natural ore mainly composed of magnesium hydroxide produced by pulverizing synthetic magnesium hydroxide produced from seawater or the like and natural brucite ore (hereinafter referred to as natural product) Any of these may also be suitably used, and the average particle size is preferably 40 μm or less, particularly preferably 0.2 to 6 μm, in view of dispersibility and flame retardancy.
From the viewpoint of whitening resistance, natural magnesium hydroxide is preferred. Naturally produced magnesium hydroxide is pulverized to adjust the average particle size. In this case, if it is ground to the synthetic magnesium hydroxide level, it is thought to be due to the destruction of the crystal system, but the whitening resistance is rather poor. It is more desirable that the ratio of 4 μm or more is 50% or less (based on the number) and the average particle size is 1.5 μm to 6 μm.

The surface-treated magnesium hydroxide in the present invention may be surface-treated by a known surface treatment method and is not particularly limited.
For example, in the case of synthetic magnesium hydroxide produced from seawater, magnesium hydroxide crystallizes in an aqueous solution, so a desired amount of a surface treatment agent is diluted in a solvent such as alcohol if necessary in this aqueous solution. It can mix | blend and make it dry after precipitation, and can manufacture the surface treatment magnesium hydroxide surface-treated with carboxylic acid ester.
Synthetic magnesium hydroxide and natural magnesium hydroxide can be produced by employing a slurry method in which, for example, an organic solvent liquid of a carboxylic acid ester is added and mixed.

Furthermore, in addition to the so-called wet method described above, surface treatment can also be performed by a dry method described below.
Already added a desired amount of carboxylic acid ester to synthetic magnesium hydroxide or natural magnesium hydroxide with an average particle size according to the purpose of use, and stirring and mixing above the temperature at which it melts, for example, 70 to 120 ° C By doing so, it can be manufactured. In this case, a known mixer such as a continuous mixer, a Banbury mixer, a kneader, a super mixer, or a ball mill may be used.
In the case of natural magnesium hydroxide, since it is used after pulverization, coarsely pulverized natural magnesium hydroxide and a desired amount of carboxylic acid ester are put in a ball mill or other pulverizer, and if necessary, carboxylic acid ester is externally supplied The surface treatment may be performed simultaneously with the pulverization while heating to a temperature at which the sol is dissolved.

3. Calcium carbonate (C)
Examples of the calcium carbonate (C) used in the present invention include heavy calcium carbonate obtained by pulverizing ore such as limestone, marble and calcite, precipitated calcium carbonate or light calcium carbonate which is a synthetic stone. Any of these can be used, but synthetic calcium carbonate having a uniform particle size distribution is preferable from the viewpoint of extrusion processability and mechanical properties.
The average particle size of calcium carbonate is 10 μm or less, preferably 4 μm or less, more preferably 3 μm or less, from the viewpoint of dispersibility, mechanical properties, and flame retardancy.
In addition, calcium carbonate is coated with a fatty acid such as stearic acid, oleic acid, palmitic acid or a metal salt thereof such as sodium, calcium, magnesium, paraffin, wax or their metamorphs, organic silane, organic titanate, etc. A surface-treated product can be used.

4). Flame Retardant Resin Composition The flame retardant resin composition of the present invention contains a predetermined amount of resin (A) and surface-treated magnesium hydroxide (B), respectively, and an appropriate amount of other compound ( Stabilizer, antioxidant, UV absorber, light stabilizer, antistatic agent, nucleating agent, lubricant, processability improver, filler, dispersant, copper damage inhibitor, neutralizing agent, foaming agent, foam inhibitor , Colorant, carbon black, carbon black masterbatch, and other flame retardants), and uniformly using, for example, a kneader, a Banbury mixer, a continuous mixer, a roll mill or an extruder. It can manufacture by melt-kneading at about 130-210 degreeC, Furthermore, blooming of a surface treating agent can be suppressed by mix | blending calcium carbonate (C).
The manufactured flame-retardant resin composition is then preferably granulated into pellets having a particle size of about 2 to 7 mm and used for molding.

  In this invention, the compounding quantity of surface treatment magnesium hydroxide (B) is 35-110 mass parts with respect to 100 mass parts of resin (A), Preferably it is 40-100 mass parts, More preferably, it is 50-99 mass parts. It is. When the blending amount of the surface-treated magnesium hydroxide (B) is less than 35 parts by mass, the desired flame retardancy aimed by the present invention cannot be obtained, while when it exceeds 110 parts by mass, the mechanical properties deteriorate, In addition, the absolute value of the blooming amount increases, which is not desirable.

Moreover, in this invention, the compounding quantity of a calcium carbonate (C) is 10-55 mass parts with respect to 100 mass parts of resin (A), Preferably it is 20-45 mass parts, More preferably, it is 25-40 mass parts. is there.
When the blending amount of calcium carbonate (C) is less than 10 parts by mass, it is insufficient to suppress the blooming amount of the carboxylic acid ester that is the surface treatment agent of the surface-treated magnesium hydroxide (B), while it exceeds 55 parts by mass. In this case, the effect of suppressing the blooming amount is saturated, and on the contrary, the mechanical properties and the extrusion processability are deteriorated.

5. Extruded product The above flame-retardant resin composition can be manufactured by using an extrusion molding machine in a known manner, and then heat-melting it and then extruding it from a mold. it can.
When the extruded product is an electric wire / cable coating layer, it can be produced by similarly extruding and coating the core wire of the electric wire / cable as an insulating layer or a sheath layer by a known method.

  EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples. In addition, preparation of the sample used in this specification and its evaluation are based on the following, respectively, except the method described individually.

"Sample preparation"
Each predetermined amount of resin (A), surface-treated magnesium hydroxide (B), calcium carbonate (C), and other appropriate amount of other ingredients as required are put into a Banbury mixer and melt-kneaded at 200 ° C. for 10 minutes. Thus, a resin composition is obtained, and pellets having an average particle diameter of about 4 mm are obtained therefrom. This is preheated to 160 ° C. for 5 minutes, 150 kgf pressurized for 3 minutes, and finally cooled to 23 ° C. while maintaining the pressure. A 1 mm thick sheet was obtained by molding and used as a sample.

"Evaluation"
I. Blooming amount (i) Gravimetric method A 15cm x 18cm rectangular sample for measurement was prepared from the obtained sample (sheet) and exposed to an environment of 40 ° C and relative humidity of 65% for 14 days. The surface of the two samples for measurement was washed twice with 20 ml of chloroform, and the surface treatment agent leached on the surface was collected, and then chloroform was distilled off to dry the leached surface treatment agent, The weight was measured.

(Ii) Fourier Transform Infrared Absorption Spectroscopy After measuring the weight by a gravimetric method, a surface treatment agent obtained with an appropriate amount of chloroform so as to have a concentration detected by the Fourier transform infrared absorption measurement method. The amount of the surface treatment agent which was dissolved and diluted and prepared from the surface treatment agent separately used and measured was quantified and evaluated by the absorbance at a wave number of 1740 cm ⁻¹ derived from the carboxylic acid group.

(Iii) Visual method Since the change in appearance of the molded product is also an important evaluation item, the measurement sample after 14 days exposure was also observed and evaluated visually by the evaluation criteria described below. Those superior to 2 were considered acceptable.
[Visual observation evaluation criteria]:
0: No leaching or accumulation of white substance is observed on the surface.
1: Slight leaching and accumulation of white substance on the surface is observed.
2: Slight leaching and accumulation of white substances are observed on the surface.
3: Exudation and accumulation of white substances are observed on the surface.
4: Many leaching and accumulation of white substances are observed on the surface.
5: Exudation and accumulation of white substances are observed on the entire surface.

II. Flame retardancy Flame retardancy was evaluated in accordance with 28 of JIS C3005. The flame-retardant resin composition was measured using a lab plast mill (“Model 20C200” manufactured by Toyo Seiki Seisakusho), an extruder (“D20-25 type” manufactured by Toyo Seiki Seisakusho), and a small wire coating device (manufactured by St. Seisakusho) Extruded at a temperature of 200 ° C. on a 1.0 mm copper core wire so as to have a coating thickness of 1.0 mm, a flame retardant inclination test cable was prepared and evaluated.
The obtained cable is about 300 mm long and supported at an incline of 60 ° C. with respect to the horizontal, and the tip of the reducing flame is applied to the position about 20 mm from the lower end of the cable until it burns within 30 seconds. After removing the cable, the degree of burning of the cable was examined. The evaluation standard of flame retardancy was based on whether or not it passed naturally disappearing within 60 seconds after removing the flame.

III. Mechanical Properties (i) Tensile Fracture Stress A test piece punched with a No. 3 dumbbell defined in 4.1 of JIS K6251 was performed in accordance with JIS C3005. Three test pieces were measured and evaluated by average value. The tensile fracture stress is assumed to be about 10 MPa.

(Ii) Tensile Fracture Strain Using a test piece similar to the tensile fracture stress test, it was performed in accordance with JIS C3005. Three test pieces were measured and evaluated by average value. The tensile fracture strain is assumed to be about 500%.

[Comparative Examples 1-3, Examples 1-3]
Using carbon black (Vulcan 9A-32, manufactured by Cabot) and ethylene-butene copolymer (melt mass flow rate 1 g / 10 min, density 0.918 g / cm ³ , Nippon Unicar, GMM-1810) as a resin The carbon black masterbatch containing 36% by mass of carbon black was prepared by melt-kneading at 200 ° C. for 10 minutes and granulating to an average particle size of 4 mm.
The resin and the carbon black masterbatch prepared above were mixed so that 4.6 parts by mass of carbon black was blended per 100 parts by mass of the resin.

  Surface treated magnesium hydroxide [glycerin-stearate ester (manufactured by Riken Vitamin) with an average esterification rate of 50%] and natural magnesium hydroxide (Magseees W, manufactured by Kamishima Chemical) at 75 ° C. per 100 parts by mass of the resin. Mixed with a supermixer for a minute and surface-treated by a dry method so that the surface treatment amount becomes 3.2% by mass, and the ratio of the particle size is 4 μm and the average particle size is 3.4 μm when the ratio is 50% or less (number basis)] 98 1 part by mass of an antioxidant tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane as a stabilizer, and 1 part by mass, A resin composition of Comparative Example 1 was obtained, and a sample was prepared therefrom.

  Calcium carbonate (heavy calcium carbonate, average particle size 1.5 μm, manufactured by Shiraishi Calcium Co., Ltd.) was added in the same manner as Comparative Example 1 except that 15 parts by mass, 25 parts by mass, and 50 parts by mass were added respectively. Samples were prepared by obtaining the resin compositions of Example 1, Example 2 and Example 3.

Moreover, the resin composition of the comparative example 2 and the comparative example 3 was obtained like the comparative example 1 except having added 5 mass parts and 100 mass parts of calcium carbonate, respectively, and the sample was prepared.
The composition of each resin composition is shown in Table 1.

The obtained samples were evaluated for blooming amount, flame retardancy, and mechanical properties, and the results are shown in Table 1. The blooming amount of Comparative Example 1 was 26.2 mg by the gravimetric method and 27.0 mg by the Fourier transform infrared absorption spectroscopic method. In Table 1, the results of the gravimetric method were compared with those of Comparative Example 1. Expressed as a percentage of blooming amount.
As is clear from Table 1, Examples 1, 2 and 3 of the present invention are comparative examples in which blooming of a carboxylic acid ester which is a surface treatment agent is performed while maintaining excellent constant flame retardancy and mechanical properties. It was a flame retardant resin composition that was significantly suppressed as compared with 1, and was excellent in visual observation. On the other hand, in Comparative Example 2 in which the blending amount of calcium carbonate was smaller than that of the present invention, blooming was suppressed too little. Comparative Example 3 in which the blending amount of calcium carbonate is larger than that of the present invention is inferior in mechanical properties of tensile fracture stress and tensile fracture strain, and in particular, flame retardancy in which tensile fracture strain is remarkably deteriorated. It was a resin composition.

[Comparative Examples 4, 5 and Examples 4, 5]
Except having changed the composition of the resin composition, it carried out similarly to Example 1, and obtained the resin composition of Comparative Examples 4, 5 and Examples 4, 5, and prepared the sample.
The composition of each resin composition is shown in Table 2.

The obtained samples were evaluated for blooming amount (not evaluated by Fourier transform infrared absorption spectroscopy), flame retardancy and mechanical properties. The results are shown in Table 2.
In Comparative Example 4 in which the amount of the surface-treated magnesium hydroxide is less than that of the present invention, the flame retardancy is rejected. On the other hand, in Comparative Example 5 in which the amount is higher than that of the present invention, the blooming amount is Comparative Example 1. It was a flame retardant resin composition in which the tensile fracture stress and tensile fracture strain of mechanical properties were inferior, and particularly the tensile fracture strain was significantly deteriorated. .
In the resin compositions of Examples 4 and 5 of the present invention, blooming of the carboxylic acid ester, which is the surface treatment agent, is suppressed while maintaining excellent and constant flame retardancy and mechanical properties. It was.

[Comparative Example 6, Example 6]
Comparative Example 6 and Example were the same as Comparative Example 1 and Example 2 except that stearyl succinate (made by Takemoto Yushi) was used as the surface treating agent and the surface treatment amount was 2.2% by mass. The resin composition of 6 was obtained and the sample was prepared.
The composition of each resin composition is shown in Table 3.

The obtained samples were evaluated for blooming amount (not evaluated by Fourier transform infrared absorption spectroscopy), flame retardancy and mechanical properties. The results are shown in Table 3.
The blooming amount of Comparative Example 6 was 8.4 mg by gravimetric method. In Table 3, the results of the gravimetric method are shown as a percentage of the blooming amount compared to Comparative Example 6.
As can be seen from Table 3, Example 6 of the present invention shows that the blooming of the carboxylic acid ester, which is the surface treatment agent, is superior to that of Comparative Example 6 while ensuring excellent and constant flame retardancy and mechanical properties. The flame-retardant resin composition was significantly suppressed to 51%.

[Comparative Example 7, Example 7]
Comparative Example 7 and Example were carried out in the same manner as Comparative Example 1 and Example 2, except that ethyl stearate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the surface treating agent and the surface treatment amount was 3.0% by mass. The resin composition of Example 7 was obtained and a sample was prepared.
The composition of each resin composition is shown in Table 4.

The obtained samples were evaluated for blooming amount (not evaluated by Fourier transform infrared absorption spectroscopy), flame retardancy and mechanical properties. The results are shown in Table 4.
The blooming amount of Comparative Example 7 was 18.2 mg by the gravimetric method, and in Table 4, the result of the gravimetric method is shown as a percentage of the blooming amount compared to Comparative Example 7.
As can be seen from Table 4, Example 7 of the present invention shows that the blooming of the carboxylic acid ester, which is the surface treatment agent, is superior to that of Comparative Example 7 while ensuring excellent and constant flame retardancy and mechanical properties. The flame-retardant resin composition was significantly suppressed to 55%.

  The present invention ensures excellent flame retardancy of the flame retardant resin composition, and the carboxylic acid ester as the surface treatment agent used has excellent compatibility between the resin and magnesium hydroxide. In addition to having excellent dispersibility and excellent mechanical properties of the flame retardant resin composition, it is also excellent in extrusion moldability, and further, blooming and leaching of the surface treatment agent is significantly suppressed. Has an excellent effect. Extruded products of this flame retardant resin composition, and electric wires / cables having a coating layer obtained by extruding the flame retardant resin composition include flame retardant covers, pipes, sheets, films, electric wire / cable coating layers, etc. It can be effectively used as an electric wire in which the concern of polluting the environment in an extruded product, particularly a semiconductor factory, has been improved.

Claims (4)

  Hydroxylation surface-treated with one or more surface treatment agents (a) selected from higher fatty acid polyhydric alcohol ester, dicarboxylic acid monoester or higher fatty acid alkyl ester with respect to 100 parts by weight of resin (A) Blooming of the surface treatment agent from the flame retardant resin composition can be achieved by further adding 10 to 55 parts by weight of calcium carbonate (C) to the flame retardant resin composition containing 35 to 110 parts by weight of magnesium (B). A method for suppressing blooming of a flame retardant resin composition, comprising suppressing the flame retardant resin composition.   The method for suppressing blooming of the flame retardant resin composition according to claim 1, wherein the surface treatment amount by the surface treatment agent (a) is 0.5 to 5.0 mass%.   Resin (A) is ethylene-type resin, The blooming suppression method of the flame-retardant resin composition of Claim 1 or 2 characterized by the above-mentioned.   The ethylene resin is at least one selected from the group consisting of a linear low density ethylene-α-olefin copolymer, an ethylene-vinyl acetate copolymer, and an ethylene-ethyl acrylate copolymer. The blooming suppression method of the flame-retardant resin composition of Claim 3.