JPS61231040A - Flame-retardance ethylene/ethyl acrylate copolymer composition - Google Patents

Abstract

PURPOSE:To obtain a flame-retardance copolymer compsn. having heat distortion temp. and excellent mechanical strength, by CONSTITUTION:A copolymer compsn. is obtd by blending 40-150pts.wt. inorg. flame retarder with 100pts.wt. component mainly composed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a flame-retardant ethylene-ethyl acrylate copolymer composition that has heat resistance, that is, a high heat distortion temperature, and excellent mechanical strength.

(Prior Art) It is well known that polyolefins' mechanical strength, water resistance, chemical resistance and their outstanding electrical properties make them suitable for wire insulation, cable sheathing, and other applications. be.

However, polyolefins are easily flammable, and in the above applications, low ff1 ((support)) S is required.

Conventionally, halogen-based flame retardants or a mixture of the halogen-based flame retardants and antimony oxide have been most commonly used to make polyolefins flame retardant, but when heated and burned, a large amount of highly toxic halogen gas and smoke are emitted. The problem is that it is not only harmful to the human body, but also corrodes surrounding equipment due to its corrosive nature.

On the other hand, it is well known that inorganic flame retardants such as magnesium hydroxide and aluminum hydroxide are effective as low-smoke flame retardants that do not generate harmful gases during combustion.

In addition, when using the above-mentioned inorganic flame retardant, oxygen-containing resins such as ethylene-vinyl acetate copolymer (hereinafter referred to as EVA) and ethylene-ethyl acrylate copolymer (hereinafter referred to as PEA) may be used as the polyolefin. It is also known that a additive flame retardant effect can be obtained when used in combination with a flame retardant effect. Among them, EEA is superior to EV& in terms of heat resistance, low-temperature properties, electrical properties, etc., and meets the recent demand for high flame retardancy, and is rapidly increasing in demand.

(For example, Japanese Patent Application Laid-Open No. 51-132254
No. 56-136832, No. 60-13832, etc. ) However, in order to improve flame retardant performance and improve receptivity to inorganic metal compounds that are flame retardants, conventional EEAs that have been commercially available have been shown to cause crystallization when the content of ethyl acrylate (hereinafter referred to as EA) is increased. It has the disadvantage that the degree of carbonization is significantly lowered, mechanical strength and thermal deformation salinity are lowered, and it is no longer practical. On the other hand, when the EA content is reduced, the receptivity to inorganic metal compounds deteriorates, and the amount of inorganic metal compounds added is naturally limited, resulting in deterioration of low-temperature properties and reduction in flame retardancy. As above, E
Although EA is preferable as a non-polluting flame retardant resin with the addition of inorganic flame retardants, conventional EEA is now required to have a high degree of flame retardancy, and in terms of mechanical strength and heat resistance, etc. It is hard to say that I am fully satisfied.

(Problems to be Solved by the Invention) In view of the above points, the present invention provides a flame-retardant composition that has particularly excellent heat resistance, mechanical strength, and low-temperature properties, is low in smoke, and is non-polluting. This flame-retardant composition is used for molding applications such as electric wires, cables, backings, sealing materials, hoses, films, and injection molded products, and as masterbatches.

c) Means for Solving Problems) The present invention is characterized in that 40 to 150 parts by weight of an inorganic flame retardant is added to 100 parts by weight of a resin component whose main component is an ethylene-ethyl acrylate copolymer.
(b) The ethylene-ethyl acrylate copolymer has a melt index of 0.2 to 59,710 minutes, and (b) the content of ethyl acrylate is in the range of 10 to 20 parts by weight. , and (c) content (E) and melting point (T) of ethyl acrylate
The present invention provides a flame-retardant ethylene-ethyl acrylate copolymer composition whose relationship satisfies the following formula %.

The ethylene-ethyl acrylate copolymer of the present invention has an ethyl acrylate content of 10 to 20% by weight, and a melt index of c or less (referred to as MI) of 0.2 to 5 f.
/10 minutes, and the ethyl acrylate content (E
) and the melting point (T) of the resin is expressed by the following formula T≧-0,8XE
It needs to be within a specific range that satisfies +109.

If the above-mentioned MI is less than 0.2t710 minutes, workability deteriorates, and if it exceeds 5f/1o minutes, strength decreases. Particularly preferred MI is in the range of 0.5 to 2 F/10 minutes.

In addition, when the EA content is less than 10% by weight, when a sufficient amount is added to make the inorganic metal compound described below flame retardant,
Mechanical strength is significantly reduced and low-temperature properties are deteriorated.

On the other hand, if it exceeds 20% by weight, the melting point will drop significantly, the heat distortion temperature will become low, and there will be no heat resistance.

From the above point, a particularly preferable EA content is 14 to 17% by weight.
is within the range of

Furthermore, in the present invention, the relationship between the EA content (E) and the melting point (T) of EEk, that is, the formula T≧-0,8XE+109
It is essentially distinguished from the conventional EEA by satisfying the following.

Only by limiting the EA content to the above-mentioned specific range can a composition meet the recent strict demands for flame retardancy.

However, the <melting point> is expressed by the maximum peak temperature (Tm) measured by differential scanning calorimetry (DSC), and is measured as follows.

That is, approximately 51q of a sample is accurately weighed, set in a DSC, heated to 170°C, held at that temperature for 15 minutes, and then cooled at a rate of 10°C/min. next,
From this state, the temperature is raised to 170°C at a rate of 10°C/min, and the measurement is completed. Maximum peak temperature (Tm) is from 0℃ to 1
The temperature is expressed as the temperature at the top of the maximum peak that appeared during the temperature increase to 70°C.

EA content> is E determined by infrared absorption spectrum (IR).
It is determined from the absorbance of 860m attributed to A.

However, the calibration curve is determined by determining the EA concentration using nuclear magnetic resonance spectroscopy (NMR) and by correlating it with the absorbance at 860 m of IR.

The EKA of the present invention, which satisfies the above relational expression between EA content (E) and melting point, was developed by the present inventors as a result of intensive studies to satisfy the above strict requirements. It is manufactured below and is structurally different from the EEA that has been proposed in the past.

That is, the EKA of the present invention, as shown in FIG.
In the relationship between EA content and melting point, the formula T≧-0,8XE
The EA content is limited to a range of 10 to 20% by weight in order to exist in the +109 line or higher range and maintain high flame retardant properties. On the other hand, the conventionally proposed EgA
exists below the above T≧−0, 8XE+109 line. Although it is not yet clear what lies within this line, it is speculated that this is due to the difference in structure due to the distribution state of the EA groups introduced into the ethylene polymer chain.

Examples of the inorganic flame retardant of the present invention include aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, basic magnesium carbonate, dolomite, hydotalcite, calcium hydroxide, barium hydroxide, tin oxide hydrate, borax, etc. Hydrates of inorganic metal compounds, zinc borate, zinc metaborate, barium metaborate, zinc carbonate, magnesium-calcium carbonate, calcium carbonate, barium carbonate, sea urchin oxide, molybdenum oxide, zirconium oxide, tin oxide, antimony oxide, Examples include red phosphorus. These may be used alone or in combination of two or more. Among these, at least one selected from the group consisting of magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, and hydrotalcite has a good flame retardant effect and is economically advantageous. The particle size of these flame retardants varies depending on the type, but for magnesium hydroxide, aluminum hydroxide, etc., the average particle size is preferably 20 μm or less.

The amount of the above inorganic flame retardant is 40 parts by weight of EEAIQQ.
-150 parts by weight, preferably 70-120 parts by weight. When the amount of the flame retardant is less than 40 parts by weight, the flame retardant effect is small, and when it exceeds 150 parts by weight, the elongation decreases.
It becomes brittle and its low temperature properties also deteriorate.

In addition to the above-mentioned inorganic flame retardants, general inorganic fillers such as clay, silica, and talc may also be used in combination.

Furthermore, it is preferable to perform surface treatment such as coating the surface of the inorganic flame retardant with a fatty acid such as stearic acid, oleic acid, palmitic acid, or a metal salt thereof, wax, organic silane, organic poran, organic titanate, or the like.

The flame retardant composition of the present invention may contain other olefin polymers, such as ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, and ethylene-methacrylic acid copolymer, to the extent that the characteristics of the present invention are not impaired. Polymers, ethylene-unsaturated carboxylic acid ester copolymers other than the scope of the present invention, high, medium, and low density ethylene homopolymers or ethylene and propylene, butene-1, pentene-1, hexene-1,
Copolymers with 3′-120 α-olefins such as 4-methylpentene-1, octene-1, and decene-1, propylene homopolymers, copolymers of propylene with other a-olefins, or ethylene Or a propylene homopolymer or a copolymer of ethylene or a copolymer containing propylene as a main component with another a-olefin modified with an unsaturated carboxylic acid such as acrylic acid or maleic acid or a derivative thereof, or a mixture thereof. There is no problem in adding it.

Furthermore, in the present invention, in order to improve the flame retardant effect, the above-mentioned inorganic flame retardant may be used in combination with a small amount of an organic flame retardant or a flame retardant auxiliary agent such as a nitrogen-based flame retardant or a phosphorus-based flame retardant. .

Further, conventional additives such as various stabilizers such as antioxidants, ultraviolet absorbers, and copper damage inhibitors, pigments, crosslinking agents, crosslinking aids, blowing agents, and nucleating agents may be added.

(Operations and Effects of the Invention) As described above, the flame-retardant composition of the present invention does not generate harmful gases during combustion, has low smoke properties, is non-polluting, and is superior to conventional flame-retardant EEA. It has excellent heat resistance and mechanical strength.
Cables for various power plants such as nuclear power research institutes that specify the amount of corrosive gases, cables for chemical, steel, petroleum, etc. plants, fire-resistant electric wires, general indoor wiring, etc. that require a high degree of flame retardancy. suitable for use in places. It can also be used for molding purposes such as films, sheets, pipes, and injection molded products, and as a masterbatch.

Examples 1 to 7 and Comparative Examples 1 to 7 <Manufacture of JEA resin> Using a tubular reactor, ethylene was produced in the presence of an initiator and a chain transfer agent at a pressure of 2500 to 3000 Kf/d and a temperature of around 250°C. and ethyl acrylate are radically copolymerized to form various EEs as shown in Table 1.
A was produced.

Magnesium hydroxide (
Product name: Kisuma 5B, manufactured by Kyowa Kagaku ■) and an antioxidant (product name: Santonox R1 manufactured by Yoshitomi Pharmaceutical ■→0)
．． 2 parts by weight were uniformly kneaded in a plastograph set at 200°C. The tensile strength, heat deformation rate, embrittlement temperature, and oxygen index of this composition were measured, and the results are shown in Table 1 (Examples 1 to 6, Comparative Examples 1 to 5). Table 1 shows the results of evaluation in the same manner as in Example 1, using aluminum hydroxide instead of magnesium hydroxide, which is the flame retardant in Example 1 (Example 7). Table 1 also shows the results of evaluation using a commercially available EEA in the same manner as in Example 1.
2. Comparative Example 7 shows an example using Mikata Polychemical's trade name A702).

<Test Method> Using a test piece made by punching out a No. 3 dumbbell from a sheet having a thickness of IX, the test piece was measured using a Tensilon at a tensile speed of 200 u+/min.

2. Heating deformation rate A cylinder with a thickness of 6X and a diameter of 10% was immersed in an oil bath at 90°C, pressurized with a load of 1.02 to 4, and the deformation rate after 30 minutes was determined.

3. Brittleness temperature Compliant with ASTM D746 4. Oxygen index Compliant with JISK7201

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between ethyl acrylate (EA) content and melting point in an ethylene-ethyl acrylate copolymer. Figure 1 EA content (Cwt%)

Claims (3)

[Claims] (1) In a composition comprising 40 to 150 parts by weight of an inorganic flame retardant to 100 parts by weight of a resin component whose main component is an ethylene-ethyl acrylate copolymer, the ethylene-ethyl acrylate copolymer ( a) Melt index is 0.2-5g/10min, (
b) The ethyl acrylate content is in the range of 10 to 20% by weight, and (c) the relationship between the ethyl acrylate content (E) and the melting point (T) satisfies the following formula T≧-0.8×E+109 A flame-retardant ethylene-ethyl acrylate copolymer composition. (2) The flame-retardant ethylene-ethyl acrylate copolymer composition according to claim 1, wherein the inorganic flame retardant is a hydrate of an inorganic metal compound. (3) The flame-retardant ethylene-ethyl acrylate copolymer composition according to claim 2, wherein the hydrate of the inorganic metal compound is aluminum hydroxide or magnesium hydroxide.