JP2003261775A - Halogen-free flame retardant composition and electric wire / cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition based on a thermoplastic resin containing no halogen and having sufficient flame retardancy, to improve acid gas resistance and further suppress whitening phenomenon. SOLUTION: An insulating wire made of a non-halogen flame-retardant composition is provided around a copper conductor to form an insulated wire. A non-halogen flame retardant composition having a weight average molecular weight of 3000
Based on a polyolefin-based resin containing 1 to 10% by weight of polyethylene having a density of 0.970 g / cm ³ or more and a molecular weight of oleic acid amide and / or erucamide based on 100 parts by weight of the polyolefin resin. 0.1 to 5 parts by weight of a fatty acid amide and 30 to 120 parts by weight of a metal hydroxide composed of magnesium hydroxide and / or aluminum hydroxide as a flame retardant.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a halogen-free thermoplastic resin such as a polyolefin resin as a base, and to improve the properties of a non-halogen flame retardant composition containing a metal hydroxide as a flame retardant. The present invention relates to a non-halogen flame-retardant composition and a wire / cable using the same.

[0002]

In recent years, with the increasing conservation of the global environment, it is possible to recycle the applied materials in electric wires and cables, and to eliminate halogenated compound gas that is harmful even when incinerated or buried. It is an important issue to develop products that do not generate dioxins, that is, have a low environmental impact. Under such circumstances, non-halogen flame-retardant compositions based on halogen-free thermoplastic resins have been actively developed. As a typical example, a large amount of a metal hydroxide such as magnesium hydroxide is added to a flammable polyolefin resin, for example, 50 to 2 per 100 parts by weight of the polyolefin resin.
A technique for adding flame retardant by adding 00 parts by weight is known.

However, when a non-halogen flame-retardant composition in which a large amount of a metal hydroxide is added to a polyolefin resin to make it flame-retardant is used, for example, as an insulating coating for electric wires, it is difficult to control electrical machinery and control. When used for wiring in a panel, for example, an electric switchboard such as a motor control center, when used in an environment such as an industrial area, a volcanic area, or in the vicinity of a sterilization facility, an oxidizing gas contained in the air, for example, nitrogen dioxide. Gas (NO ₂ ), sulfurous acid gas (SO ₂ ), chlorine gas (Cl ₂ ) and the like react with metal hydroxide in the insulating coating to produce nitric oxide, sulfate and chloride on the surface of the coating. There is. Since the product has a property of easily absorbing moisture in the air (hygroscopicity, deliquescent), the insulation resistance (surface meg) on the surface of the insulated wire is significantly reduced.

For example, when magnesium hydroxide is taken as an example of the metal hydroxide, the reaction with the nitrogen dioxide gas at this time is represented by the following chemical reaction formula. 2NO ₂ + H ₂ O → HNO ₃ + HNO ₂ (0) Mg (OH) ₂ + 2HNO ₃ → Mg (NO ₃ ) ₂ + 2H ₂ O (1) Metal hydroxide is relatively easy by such a mechanism. In addition, it reacts with the acidic gas in the atmosphere to form an oxide, which leads to a decrease in surface meg.

By the way, the present inventors conducted a test for checking the acid gas resistance of the above-mentioned conventional electric wire. In this test, a sample (conventional electric wire) was put into a gas corrosion tester capable of simultaneously adding oxidizing gas and humidity, and NO ₂ gas having an extremely low concentration of 10 ppm as oxidizing gas was used. It was carried out by exposing it to an atmosphere having a humidity of 90% RH for 10 days and measuring the change of its surface meg.
As a result, it was found that the surface meg of the conventional electric wire is lowered by 3 to 5 digits.

Further, as a harmful effect of adding a large amount of metal hydroxide, the excellent mechanical properties of the polyolefin resin are impaired, and a halogen-based flame-retardant composition known in the prior art, such as polyvinyl chloride or bromine, is used. The mechanical strength is inferior to that of the composition containing the flame-retardant material, and even if the product surface is rubbed or bumped with a comparatively small force, it is easily scratched and the part becomes white. There is also a problem (so-called "whitening phenomenon"). Therefore, when this composition is used for the insulation coating of electric wires or cables, it has a drawback that it is bleached due to an unavoidable external force during laying work or the like, resulting in a marked decrease in commercialability.

The present invention has been made in view of the above circumstances, and an object thereof is a composition containing a halogen-free thermoplastic resin as a base and having sufficient flame retardancy and having excellent acid gas resistance. Moreover, it is to provide a non-halogen flame-retardant composition and an electric wire / cable that can suppress the whitening phenomenon.

[0008]

Means for Solving the Problems The present inventors have proposed a halogen-free flame-retardant composition containing a halogen-free thermoplastic resin such as a polyolefin resin as a base and containing a metal hydroxide as a flame retardant. Therefore, in order to achieve the above object, as a result of repeated studies, it was found that by blending a fatty acid amide in a predetermined ratio, it was effective in improving acid gas resistance and preventing a whitening phenomenon, and achieved the present invention. It was. That is, the halogen-free flame-retardant composition of the present invention is obtained by adding a thermoplastic resin containing no halogen to the thermoplastic resin 100.
It is characterized in that 0.1 to 5 parts by weight of fatty acid amide and 30 to 120 parts by weight of metal hydroxide are blended with respect to parts by weight (invention of claim 1).

By blending the fatty acid amide, the fatty acid amide has a function of coating the surface of the metal hydroxide and making the direct contact between the acid gas and the metal hydroxide less likely to occur. In addition, the fatty acid amide has water repellency and imparts a property of being hard to be wet with the metal hydroxide. For these reasons, the reaction of the metal hydroxide can be made difficult to occur, and the acid gas resistance can be improved. Moreover, the fatty acid amide makes the surface of the composition slippery, and the initial catching that may cause scratches against mechanical external force is less likely to occur, and the whitening phenomenon can be suppressed.

In this case, the blending amount of this fatty acid amide is
0.1 to 100 parts by weight of the base thermoplastic resin
5 to 5 parts by weight is preferable, and if it is less than 0.1 parts by weight, sufficient acid gas resistance and whitening resistance cannot be obtained, and even if it is added in excess of 5 parts by weight, acid gas resistance and The whitening prevention property is not further improved, but rather the appearance of the product may be deteriorated due to bleeding out.

The metal hydroxide functions as a flame retardant, and the amount of the metal hydroxide blended is the thermoplastic resin 1 as the base.
The amount is preferably 30 to 120 parts by weight with respect to 00 parts by weight, whereby sufficient flame retardancy can be obtained for the composition and the whitening prevention property can be secured. When the amount is less than 30 parts by weight, sufficient flame retardancy cannot be obtained, and when the amount exceeds 120 parts by weight, the whitening preventive property is deteriorated, which is not preferable.

At this time, when the thermoplastic resin as the base is made of a polyolefin resin, the weight average molecular weight is 3000 to 5000 and the density is 0.970 g / cm.
It will be more effective if it contains ³ to 10% by weight of polyethylene (invention of claim 2). Since this polyethylene imparts an appropriate hardness to the composition, it is possible to increase the scratch resistance to mechanical external force, that is, the effect of preventing the whitening phenomenon can be further improved.

In this case, the weight average molecular weight is 3000 to 5
000 and the density is 0.970 g / cm ^ThreeMore Polyethylene
Is desirable, and the weight average molecular weight is less than 3000
And the effect of imparting hardness decreases, exceeding 5,000
If this happens, the processability such as extrusion of the composition will be adversely affected.
Occurs. The density is 0.970 g / cm^ThreeLess than
The effect of adding hardness is small and it is difficult to get the desired scratches.
Will not be obtained. Furthermore, the content of this polyethylene
Is preferably 1 to 10% by weight, and if less than 1% by weight,
If the desired scratch resistance cannot be obtained and exceeds 10% by weight, the
This causes adverse effects such as a decrease in the elongation of the product.

According to the research conducted by the present inventors, the use of oleic acid amide and / or erucic acid amide as the fatty acid amide was most effective from the viewpoint of preventing the whitening phenomenon. Invention of 3). In this case,
Either one of oleic acid amide and erucic acid amide may be used alone, or both may be mixed and used.

Magnesium hydroxide or aluminum hydroxide can be used as the metal hydroxide (invention of claim 4). These two types of metal hydroxides are highly effective as flame retardants and are suitable for the present invention.
Also in this case, it suffices to include one or both of magnesium hydroxide and aluminum hydroxide.

Further, it is more preferable that the metal hydroxide is surface-treated with a silane coupling agent (invention of claim 5), whereby the metal hydroxide and the fatty acid amide are more familiar. In addition, the affinity between the metal hydroxide and the polyolefin can be enhanced, and the effects of acid gas resistance and whitening prevention can be further enhanced.

The halogen-free flame-retardant composition of the present invention can be used for coating electric wires and cables (the invention of claim 6). As a result, the electric wire / cable can be sufficiently applied to an environment such as an industrial area, a volcanic area, and the vicinity of a sterilization facility and the like, and has high environmental resistance. In general, a single wire that conducts electricity with an insulating coating and is used for wiring inside the equipment is called an electric wire (insulated electric wire). Those provided with a sheath are referred to as cables, but in the present specification, they are collectively referred to as “electric wires / cables”.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments in which the present invention is applied to an insulated wire will be described below with reference to the drawings.
The insulated wire of the example is constituted by, for example, surrounding the copper conductor with an insulating coating made of the halogen-free flame-retardant composition according to the present invention. The non-halogen flame-retardant composition of Example is
Halogen-free thermoplastic resin In this case, a polyolefin resin is used as a base, and in this polyolefin resin, polyethylene having a weight average molecular weight of 3000 to 5000 and a density of 0.970 g / cm ³ or more is 1-1.
0% by weight is contained. Then, 0.1 to 5 parts by weight of fatty acid amide and 30 to 120 parts by weight of metal hydroxide as a flame retardant are mixed with 100 parts by weight of the base polyolefin resin.

Specifically, in Example 1, 5% by weight of polyethylene having a weight average molecular weight of 4000 and a density of 0.980 g / cm ³ was contained in the polyolefin resin.
In this case, examples of the polyolefin resin include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and ultra low density polyethylene (VLDP).
E), ethylene-ethyl acrylate copolymer (EE
A), ethylene / vinyl acetate copolymer (EVA), ethylene / methyl methacrylate copolymer (EMMA) and the like can be adopted.

Then, oleic acid amide and erucic acid amide as fatty acid amides were added to the polyolefin resin in an amount of 2 parts by weight per 100 parts by weight of the polyolefin resin. As a metal hydroxide, finely powdered magnesium hydroxide 120
Parts by weight were mixed and mixed at room temperature. Further, at this time, the surface of the finely powdered magnesium hydroxide is previously surface-treated with a silane coupling agent.

Then, the mixture is put into a Banbury mixer, and the composition is obtained by melting and mixing for about 15 minutes while heating at 180 ° C., for example. Using the obtained composition as a molding material, for example, around a copper electric wire having a diameter of 1.8 mmφ so that the outer diameter is about 3.4 mmφ,
By performing extrusion molding using an extrusion molding machine, an insulated electric wire coated with an insulating coating made of the halogen-free flame-retardant composition according to the present invention was obtained.

Now, in order to confirm that the insulated wire of Example 1 described above has a high effect of suppressing the whitening phenomenon and is excellent in acid gas resistance, the following several tests were conducted,
We compared the conventional insulated wire. The conventional product is
Based on a flammable polyolefin resin, magnesium hydroxide as a metal hydroxide was added in 200 parts by weight to 100 parts by weight of the polyolefin resin to make it flame-retardant. Flame-retardant composition,
It is an insulated electric wire which is coated in the same manner as above (equivalent diameter) to the periphery of a copper electric wire.

First, a test for evaluating the whitening property was conducted as follows. That is, JISC3003-198
Using the abrasion resistance tester shown in item 10 of "Enamel Conductor and Enamel Aluminum Wire Test Method" of 4, the side surface of the needle attached to the abrasion resistance tester is connected to the insulated wire of Example 1 and the conventional product. By rubbing against an insulated wire,
The number of times required for the insulating coating to reach whitening was determined. As a result, while the conventional product whitened about 5 times on average, whitening was not observed in Example 1 unless it was rubbed at least 1000 times.

As described above, it was revealed that the whitening property of Example 1 was significantly improved as compared with the conventional one. The reason is that by blending an appropriate amount of fatty acid amides (oleic acid amide and erucic acid amide), the fatty acid amide coats the surface of the metal hydroxide, the surface of the composition becomes slippery, and mechanical external force It is difficult to cause the first catch that will cause scratches, and by adding polyethylene having excellent mechanical strength to the base polyolefin resin, it is possible to impart appropriate hardness to the composition. It is presumed that it is possible to improve the scratch resistance to mechanical external force, and further to suppress the compounding amount of magnesium hydroxide, which causes whitening, to be smaller than the conventional amount. Moreover, because magnesium hydroxide is surface-treated with a silane coupling agent, the affinity between magnesium hydroxide and the polymer can be increased, and magnesium hydroxide is not exposed on the surface, which is part of the reason. it is conceivable that.

Next, a test for evaluating acid gas resistance was conducted. In this case, the above (“Problems to be solved by the invention”)
In the test method for acid gas resistance described in (1) above, it is necessary to expose for a long time, and there may be cases where it is not clear numerically due to variations in the results. The test method of immersing and measuring the weight change and surface meg was adopted. As a result, clear evaluation can be obtained in a relatively short time.

That is, the insulated wire of Example 1 and the insulated wire of the conventional product are sealed at both ends with an epoxy resin adhesive so that the copper conductor does not come into direct contact with the acid, and these are treated with 10
% Nitric acid and 10% hydrochloric acid were also dipped, and periodically taken out to measure the weight change rate and the surface meg.
The weight change rate was obtained by subtracting the weight of the copper conductor as the weight change rate of only the insulating coating. Regarding the surface meg, two thin wires made of platinum and having a diameter of 0.3 mmφ were wound around the electric wire at a distance of 30 mm, and the surface was dried, and the measurement was performed using an insulation resistance meter.

FIG. 1 shows the test results for examining the weight change rate when immersed in nitric acid. As is clear from FIG. 1, in the case of 28 days of immersion, the conventional product has about 38
%, The weight loss in Example 1 was as small as about 8%. In addition, FIG. 2 shows the test results of examining the change of the surface MEG when immersed in hydrochloric acid. From this result, in the conventional product, although the initial value of the surface meg was about 1 × 10 ⁹ MΩ, it was found that after immersion for only 3 days,
It dropped to about 100 MΩ. On the other hand, in Example 1, the initial values were equivalent, and there was almost no decrease from the initial values even after immersion for 8 days.

From these results, it was revealed that the acid gas resistance in Example 1 can be remarkably improved as compared with the conventional one. This is because when a proper amount of fatty acid amide (oleic acid amide and erucic acid amide) is added, the fatty acid amide coats the surface of magnesium hydroxide and makes it difficult for direct contact between acidic gas and magnesium hydroxide. In addition, the fatty acid amide has water repellency, and since the property that the metal hydroxide is hard to be wetted is imparted, it is considered that the reaction of the metal hydroxide can be made difficult to occur. To be done. Moreover, since the magnesium hydroxide is surface-treated with a silane coupling agent, the compatibility between the magnesium hydroxide and the fatty acid amide is further improved, and it is considered that the coating is performed satisfactorily.

Further, in order to investigate the influence on the flame retardancy due to the change in the composition between the conventional product and that of Example 1, a flame retardant test was conducted. This test is based on JISC3005-199.
The flame-retardant test was carried out by using the 60-degree tilt method shown in item 28 of 3 "Rubber / Plastic Insulated Wire Test Method". As a result, the conventional product extinguished the flame immediately after the flame was removed,
In Example 1, the flame was extinguished within 1 second, and the flame extinguishing time was slightly increased. It is presumed that this is because the blending amount of magnesium hydroxide as the flame retardant was reduced.

However, the standard of the flame-extinguishing time in this class of insulated wire is, for example, the Japan Electric Wire Industry Association Standard JCS416-19 which defines the standard of the EM-IE line indicating the type of wire.
In 98, it is said that the flame is extinguished within 60 seconds, and the above-mentioned slight increase in the flame extinction time does not cause any problem in practical use.

Furthermore, the present inventors have found that the optimum blending of fatty acid amides (oleic acid amides and erucic acid amides) with the base resin and metal hydroxides (magnesium hydroxide and aluminum hydroxide) as flame retardants. A test was conducted to confirm the range of amounts. That is, as shown in Table 1 given later, Examples 2 to 5 are compositions having a composition included in the scope of claims (Claim 1),
A polyolefin resin as a base (100 parts by weight) contains a fatty acid amide and a metal hydroxide.

Specifically, Example 2 contains 0.1 part by weight of oleic acid amide and 60 parts by weight of magnesium hydroxide, and Example 3 contains 0.1 part by weight of erucic acid amide and water. Example 4 contained 120 parts by weight of magnesium oxide, and Example 4 included 1 part by weight of oleic acid amide and 1 part by weight of erucic acid amide (total 2 parts by weight) and 60 parts by weight of magnesium hydroxide and aluminum hydroxide (total of 120 parts by weight). Example 5 contains 1 part by weight of oleic acid amide and 30 parts by weight of magnesium hydroxide, and 50 parts by weight of calcium carbonate as a bulking agent.

On the other hand, the composition of Comparative Example has a composition outside the scope of the claims (Claim 1), and the composition based on the same polyolefin-based resin as in Example is used in Comparative Example 1 Then, assuming that fatty acid amide is not included,
In Comparative Example 2, the amount of the metal hydroxide (magnesium hydroxide) compounded was too small (20 parts by weight), and in Comparative Example 3, the amount of the fatty acid amide compounded was too large (total 6 parts by weight).

The test was evaluated by examining the samples of Examples 2 to 5 and Comparative Examples 1 to 3 for flame retardancy, acid gas resistance and appearance (presence or absence of surface bleeding). The results are shown in Table 1 below. In the evaluation, good ones are shown by “◯” and bad ones are shown by “x”.

[0035]

[Table 1]

As is clear from this result, Examples 2 to 2
No. 5, the flame-retardant property, the acid gas resistance, and the good results were obtained with respect to all of the appearance, whereas the comparative example 1 containing no fatty acid amide was inferior in the acid gas resistance, and In Comparative Example 3 in which the amount of fatty acid amide was excessive, although the acid gas resistance was good, surface bleeding deteriorated the appearance. In Comparative Example 2 in which the amount of metal hydroxide was too small, the flame retardancy was not sufficient. From these, the amount of the fatty acid amide is preferably 0.1 to 5 parts by weight, and the amount of the metal hydroxide is 30 to 120 parts by weight, based on 100 parts by weight of the base thermoplastic resin. Can be said to be preferable.

As described above, the insulated wire (non-halogen flame-retardant composition) of the example is a composition based on polyolefin resin and having sufficient flame resistance, and is excellent in acid gas resistance. Moreover, the whitening phenomenon can be suppressed. As a result, even if it is used for wiring in an electric machine or control panel used in an environment such as an industrial area, a volcanic area, or in the vicinity of a sterilization facility, etc. It is possible to maintain good insulation performance by suppressing the reaction with volatile gas, and also to ensure high commercialability without being bleached by external force that cannot be avoided during installation work. .

In Example 1 described above, the same amount of oleic acid amide and erucic acid amide was added as the fatty acid amide, but the same effect can be obtained with either one. It was clarified that the type and the ratio of the above influence the smoothness of the surface of the insulated wire, the workability by an extrusion molding machine, the tactile sensation, and the type of polyolefin. Further, as a flame retardant, even if magnesium hydroxide is replaced with aluminum hydroxide, the same effect is exhibited, and it is necessary to change the blending ratio thereof depending on the type of polyolefin used, and the degree of flame retardancy is also affected. It became clear to do.

In addition, the base resin is not limited to the polyolefin resin, and any halogen-free thermoplastic resin can be adopted. Furthermore, the non-halogen flame-retardant composition of the present invention can be used. The present invention does not depart from the gist of the present invention, such as being useful as an insulating material (plastic part) used in various electric devices, such as a material for molding and sealing of a mold transformer, etc., as well as coating of electric wires and cables. Within the range, it can be appropriately modified and implemented.

[0040]

As is apparent from the above description, according to the present invention, a thermoplastic resin containing no halogen such as a polyolefin resin is used as a base, has sufficient flame retardancy, and has a low environmental load. A non-halogen flame-retardant composition, which is excellent in acid gas resistance and can suppress the whitening phenomenon.

[Brief description of drawings]

FIG. 1 is a diagram showing test results for examining the rate of weight change when an insulated wire is immersed in nitric acid.

FIG. 2 is a diagram showing test results for examining changes in surface megs when an insulated wire is immersed in hydrochloric acid.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01B 3/00 H01B 3/00 A 3/44 3/44 FM MP 7/295 7/34 B (72 ) Inventor Shin Yoshida, 2-1-1 Oda Sakae, Kawasaki-shi, Kanagawa Awa Electric Cable Denki Co., Ltd. (72) Inventor, Mihoko Tanimoto 2-1-1, Oda Sakae Kawasaki-shi, Kanagawa Akira Electric Cable Denki Co., Ltd. F-term (reference) 4J002 BB011 BB032 BB062 BB072 BB082 DE077 DE147 EP016 FB097 FD077 GQ01 5G303 AA06 AA08 AB20 BA12 CA09 CA11 5G305 AA02 AB25 AB35 AB40 CD12 CD02 CD02 CD02 CD02 CD02 CD17 CD02 CD02 CD02 CD02 CD02 CD02 CD02 CD03

Claims (6)

[Claims] 1. A thermoplastic resin containing no halogen, 0.1 to 5 parts by weight of fatty acid amide, and 30 to 120 parts by weight of metal hydroxide, relative to 100 parts by weight of the thermoplastic resin.
A non-halogen flame-retardant composition formulated by weight. 2. The thermoplastic resin comprises a polyolefin resin and has a weight average molecular weight of 3,000 to 5,000.
And polyethylene with a density of 0.970 g / cm ³ or more,
The non-halogen flame-retardant composition according to claim 1, wherein the non-halogen flame-retardant composition is contained in an amount of 1 to 10% by weight. 3. The halogen-free flame-retardant composition according to claim 1, wherein the fatty acid amide comprises oleic acid amide and / or erucic acid amide. 4. The halogen-free flame-retardant composition according to claim 1, wherein the metal hydroxide comprises magnesium hydroxide and / or aluminum hydroxide. 5. The halogen-free flame-retardant composition according to any one of claims 1 to 4, wherein the metal hydroxide is surface-treated with a silane coupling agent. 6. An electric wire / cable having a coating made of the halogen-free flame-retardant composition according to any one of claims 1 to 5.