JPH07216146A - Flame-retardant cross-linkable polyolefin resin composition - Google Patents

Abstract

PURPOSE:To improve the flame retardancy of a polyolefin resin by compounding it with specified amts. of at least one specific nitrogen compd. and a polyphosphric ester. CONSTITUTION:This resin compsn. is obtd. by mixing 100 pts.wt. polyolefinic resin (e.g. PP), 0.5-30 pts.wt. at least one nitrogen compd. selected from among those of formulas I and II (wherein R<1> to R<6> each is H, an alkyl, or a group having a terminal ethylenically unsatd. bond)(e.g. triacryl cyanurate), 3-100 pts.wt. polyphosphoric ester of formula III (wherein R<7> to R<9> each is H, NH4, or CONH2; and (n) is 20 or higher) in a wt. ratio of the nitrogen compd. to the ester of (1:40)-(1:1), a polyfunctional monomer (e.g. divinylbenzene), an antioxidant, a filler, etc. The compsn. is formed into sheet and exposed to an electron beam, etc., to give a molding with a degree of cross-linking of about 5-90%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant crosslinkable polyolefin resin composition.

[0002]

2. Description of the Related Art Polyolefin resin compositions are used for the purpose of improving mechanical strength and heat resistance by a method of adding a peroxide and heating, and of ionizing radiation such as electron beams, γ-rays and X-rays. It is widely used as a foam, an electric wire coating, a heat-shrinkable tube, etc. by crosslinking by a method such as irradiation.

Since the above-mentioned polyolefin resin composition is inherently easy to burn, it has recently been required to impart flame retardancy with the expansion of its intended use, and flame retardation is carried out by various methods. It has been.

As a method of making the above polyolefin resin composition flame-retardant, a method of adding a halogen-containing compound is generally used.

With the above method, a high degree of flame retardancy can be imparted, but since a large amount of corrosive gas is generated during processing and combustion, there is a problem of corrosion of peripheral equipment and harmfulness to human body. There is a strong demand for flame retardant methods that do not use compounds.

A flame-retardant method without using a halogen-containing compound is, for example, a method of adding a hydrated metal oxide such as aluminum hydroxide, magnesium hydroxide, or basic magnesium carbonate which does not generate a toxic gas during combustion. But,
JP-A-49-5171 and JP-A-3-269029
JP-A-3-217456 discloses a method of adding polyphosphoric acid esters.

However, in the method of adding the hydrated metal hydroxide, a large amount of hydrated metal hydroxide is added in order to impart sufficient flame retardancy to the easily flammable polyolefin resin. Required, processability is reduced, and product quality is reduced.

Further, the method using the above-mentioned polyphosphate ester is not sufficient in practical flame retardancy.

As a method for improving the above flame retardancy, ammonium polyphosphate and tris (2-hydroxyethyl)
A method using a mixture of isocyanurates is disclosed in JP-A-63 / 63
-61055 gazette.

However, in the above method, there is a problem that the workability is deteriorated during the secondary processing because the mixture deposits on the surface and produces an unpleasant odor.

In addition, when the above mixture is used for flame-retarding a polyolefin-based foamed resin composition comprising a polyolefin-based resin and a foaming agent, usually, further, as a crosslinking aid,
There is a problem that it is necessary to add a polyfunctional monomer and it takes a lot of time to mix.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and it is an object of the present invention to have a high flame retardancy without using a halogen-containing compound, and It is intended to provide a polyolefin-based flame-retardant crosslinkable resin composition having excellent subsequent processability.

[0013]

The polyolefin resin used in the present invention includes polypropylene resin, polyethylene resin, polybutene resin, polypentene resin, and the like. For example, as the polypropylene resin,
Examples thereof include propylene homopolymer (polypropylene) and copolymers containing propylene as a main component.

Examples of the above copolymers include propylene / α-olefin copolymers, and examples of the α-olefins include ethylene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-butene, 1-
Penten etc. are mentioned.

Examples of the polyethylene resin include ethylene homopolymer (polyethylene) and copolymers containing ethylene as a main component.

Examples of the above copolymers include ethylene / α-olefin copolymers, and examples of the α-olefins include 1-hexene, 4-methyl-1-pentene, 1-octene and 1-octene. Butene, 1-pentene and the like can be mentioned.

Examples of polyolefin resins other than those mentioned above include ethylene / vinyl acetate copolymers and ethylene / ethyl acrylate copolymers.

The polyolefin resin used in the present invention may be a mixture of the above polyolefin resins.

Examples of the nitrogen-containing compound represented by the general formula (1) used in the present invention include cyanuric acid triallyl ester, cyanuric acid diallyl monopropyl ester, cyanuric acid (tri) homoallyl ester and cyanuric acid triaryl ester. Acryloyl ester, cyanuric acid monovinyl ester, cyanuric acid monomethyl monovinyl ester, cyanuric acid divinyl ester, cyanuric acid dimethyl monovinyl ester, cyanuric acid monoallyl ester, cyanuric acid diallyl ester, cyanuric acid monomethyl monoallyl ester, cyanuric acid dimethyl monoallyl ester, etc. Is mentioned.

Examples of the nitrogen-containing compound represented by the general formula (2) used in the present invention include isocyanuric acid triallyl ester, isocyanuric acid (N-propyl) diallyl ester, isocyanuric acid (N-ethyl) diallyl ester. , Isocyanuric acid (N-ethyl) allyl vinyl ester, isocyanuric acid (tri) homoallyl ester, isocyanuric acid triacryloyl ester, isocyanuric acid monovinyl ester, isocyanuric acid divinyl ester, isocyanuric acid monomethyl monovinyl ester, isocyanuric acid dimethyl monovinyl ester, isocyanuric acid Acid monoallyl ester, isocyanuric acid diallyl ester, isocyanuric acid monomethyl monoallyl ester and the like.

When the amount of the above-mentioned nitrogen-containing compound added is small, the degree of crosslinking of the obtained polyolefin-based flame-retardant resin molded product is insufficient, and sufficient flame retardancy cannot be obtained. Since the mechanical properties of the resin molded product deteriorate and it cannot be used, polyolefin resin 1
It is 0.5 to 30 parts by weight, preferably 1 to 15 parts by weight, based on 00 parts by weight.

The above-mentioned degree of crosslinking is obtained, for example, by heating a sample of weight (ag) at 120 ° C. for 24 hours in xylene, and then,
Calculated by the following formula from the dry weight (bg) of the residue when filtered through a 200-mesh wire mesh

Crosslinking degree (%) = (b / a) × 100

Examples of the polyphosphate ester compound represented by the general formula (3) used in the present invention include ammonium polyphosphate, ammonium carbamyl polyphosphate, polyphosphoric acid amide and the like.

When the amount of the above polyphosphate ester compound added is small, the flame retardancy of the obtained polyolefin flame-retardant crosslinkable resin composition is insufficient, and when it is too large, the mechanical properties of the polyolefin flame-retardant resin molding are improved. Since it decreases and cannot be used, it is 3 to 100 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the polyolefin resin.

The weight ratio of the nitrogen-containing compound to the polyphosphate ester compound is 1:40, since the flame retardancy is lowered, the ratio of the nitrogen-containing compound to the polyphosphate ester compound is 1:40.
It is 1: 1.

The polyolefin-based flame-retardant crosslinkable resin composition of the present invention has the above-mentioned constitution, but in addition to the above, a flame-retardant auxiliary agent such as hydrated metal hydroxide, basic magnesium carbonate and red phosphorus is added. Well, as the red phosphorus, moisture resistance, from the viewpoint of preventing spontaneous ignition at the time of kneading, red phosphorus particles whose surface is coated with a resin are preferable, and the addition amount of the flame retardant aid increases, Since the mechanical properties of the polyolefin-based flame-retardant resin molded article deteriorate and cannot be used, 100 parts by weight or less is preferable with respect to 100 parts by weight of the polyolefin-based resin.

Additives other than those mentioned above include divinylbenzene, diallylbenzene, trimethylolpropane trimethacrylate, ethylvinylbenzene, 1,9-nonanediol dimethacrylate, trimellitic acid triallyl ester, isophthalic acid diallyl ester and the like. Functional monomers; phenol-based, amine-based, sulfur-based, etc. antioxidants; metal damage inhibitors; fillers; antistatic agents; stabilizers;
Examples include pigments and the like.

The polyolefin flame-retardant crosslinkable resin composition of the present invention is melt-kneaded using a known kneading device such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneader mixer, or a roll, It is formed into a sheet, crosslinked and used.

Means for cross-linking the above-mentioned polyolefin flame-retardant cross-linkable resin composition may be irradiation with ionizing radiation such as electron beam or γ-ray, or may be previously applied to the polyolefin-based flame-retardant cross-linkable resin composition. Add oxide,
Examples include a method of heating above the decomposition temperature of the peroxide and crosslinking.

When the electron beam is irradiated, if the irradiation dose is too low, a sufficient degree of crosslinking cannot be obtained, and if it is too high, the degree of crosslinking becomes too high, and the mechanical strength of the obtained polyolefin resin molded article decreases. , Irradiation dose is 0.5 ~ 20Mr
ad is preferable, and more preferably 1-8 Mrad.

The above-mentioned peroxides include, for example, benzoyl peroxide, octanoyl peroxide, decanoyl peroxide, acetyl peroxide, tertiary butyl peroxyisobutyrate, cumene hydroperoxide, etc. If so, a sufficient degree of cross-linking cannot be obtained, and if the degree of cross-linking increases, the degree of cross-linking will increase and the mechanical strength of the polyolefin-based flame-retardant resin molded article will decrease. ~ 1 part by weight.

The cross-linking degree is usually preferably 5 to 90%, more preferably 10 to 70%, and the cross-linking methods may be used alone or in combination.

The polyolefin-based flame-retardant crosslinkable resin composition of the present invention is molded, crosslinked or molded and crosslinked,
Next, when it is used as a foam obtained by foaming or when it is used as a wire covering, a heat shrinkable tube, etc. without foaming, it has remarkable flame retardancy, and it has a harmful halogen-based gas content during combustion and processing. It is characterized in that it does not occur, has excellent secondary processability, and does not require the addition of a crosslinking aid for crosslinking.

[0035]

EXAMPLES Next, examples of the present invention will be described. In the following, "parts" means "parts by weight".

(Example 1) 100 parts of polypropylene, 3.5 parts of cyanuric acid triallyl ester and 20 parts of ammonium polyphosphate were used in 17 parts using a Labo Plastomill.
Kneading for 5 minutes under conditions of 0 ° C. and screw rotation speed of 60 RPM, followed by press molding at 170 ° C., thickness 0.4 mm
Created a sheet of. The obtained sheet was irradiated with an electron beam at an accelerating voltage of 700 KV for 4 Mrad to prepare a crosslinked sheet having a crosslinking degree of 38%.

Example 2 70 parts of polypropylene, 30 parts of polyethylene, 5.0 parts of cyanuric acid (tri) homoallyl ester and 30 parts of ammonium polyphosphate were used at 170 ° C. and a screw rotation speed of 6 using a Labo Plastomill.
The mixture was kneaded under the condition of 0 RPM for 5 minutes, and then press-molded at 170 ° C. to form a sheet having a thickness of 0.4 mm, and the obtained sheet was irradiated with an electron beam at an accelerating voltage of 700 KV for 6 Mrad, and the degree of crosslinking was 50%. A crosslinked sheet was created.

Example 3 50 parts of polypropylene, 50 parts of polyethylene, 5.0 parts of isocyanuric acid triallyl ester and 40 parts by weight of ammonium polyphosphate were used at 170 ° C. and a screw rotation speed of 60 RPM using a Labo Plastomill. Knead under conditions for 5 minutes, then 170 ℃
Press-molding with to produce a sheet with a thickness of 0.4 mm, and electron beam is applied to the obtained sheet at an acceleration voltage of 700 KV for 3 Mra.
This was irradiated with d to prepare a crosslinked sheet having a crosslinking degree of 30%.

(Example 4) 70 parts of polypropylene, 30 parts of poly (1-butene), 6.0 parts of isocyanuric acid triacryloyl ester and 40 parts by weight of carbamyl ammonium polyphosphate were added to 170 parts using Laboplast mill.
Knead for 5 minutes at 60 ° C. and then 170
Press molding at ℃, create a sheet with a thickness of 0.4 mm,
An electron beam was applied to the obtained sheet at an acceleration voltage of 700 KV for 6.5.
Mrad irradiation was performed to prepare a crosslinked sheet having a crosslinking degree of 48%.

(Example 5) 100 parts of polypropylene, 6.5 parts of cyanuric acid (tri) homoallyl ester, 50 parts of polyphosphoric acid amide and 0.8 parts of benzoyl peroxide.
Using a Labo Plastomill, 250 ° C, screw
The peroxide was decomposed by kneading for 5 minutes at a rotation speed of 60 RPM, and a kneaded material having a crosslinking degree of 33% was press-molded at 190 ° C. to prepare a crosslinked sheet having a thickness of 0.4 mm.

Example 6 50 parts of polypropylene, 50 parts of polyethylene, 5.0 parts of isocyanuric acid triallyl ester and 70 parts of ammonium polyphosphate were used at 250 ° C. and a screw rotation speed of 60 using a Labo Plastomill.
The peroxide was decomposed by kneading for 5 minutes under the RPM condition, and a kneaded material having a degree of crosslinking of 53% was press-molded at 190 ° C. to prepare a crosslinked sheet having a thickness of 0.4 mm.

(Example 7) 100 parts of polypropylene, 3.0 parts of triallyl isocyanuric acid ester and 20 parts of polyphosphoric acid amide were added to 250 parts using Laboplast mill.
C. and the screw rotation speed is 60 RPM to knead for 5 minutes to decompose the peroxide and press-mold a kneaded product having a crosslinking degree of 33% at 190.degree. C. to form a crosslinked sheet having a thickness of 0.4 mm. did.

(Comparative Example 1) 100 parts of polypropylene and 3.5 parts of cyanuric acid triallyl ester were added to polylactic acid ester without adding polyphosphoric acid esters, and 170 parts were obtained using Laboplast mill.
Kneading at a screw rotation speed of 60 RPM for 5 minutes, and then press-molded at 170 ° C. to a thickness of 0.4 mm.
The sheet was prepared, and the obtained sheet was irradiated with an electron beam at an acceleration voltage of 700 KV at 4.0 Mrad to prepare a crosslinked sheet having a crosslinking degree of 40%.

Comparative Example 2 100 parts of polypropylene, 4.5 parts of divinylbenzene and 20 parts of ammonium polyphosphate were used in a Labo Plastomill at 170 ° C. and a screw rotation speed of 60 RPM without adding a nitrogen compound. Kneading for 5 minutes, and then press-molding at 170 ° C. to form a sheet having a thickness of 0.4 mm, and irradiating the obtained sheet with an electron beam at an accelerating voltage of 700 KV at 5.0 Mrad to achieve a crosslinking degree of 45%. Created a sheet.

Comparative Example 3 50 parts of polypropylene, 50 parts of polyethylene, 3.5 parts of isocyanuric acid triacryloyl ester and 1.0 part of ammonium polyphosphate were used at 170 ° C. and a screw rotation speed of 60 RPM using a Labo Plastomill. Knead under conditions for 5 minutes, then 170 ℃
Press-molding to make a sheet with a thickness of 0.4 mm, and electron beam is applied to the obtained sheet at an acceleration voltage of 700 KV for 3.5 M.
Radiation was performed to prepare a crosslinked sheet having a degree of crosslinking of 32%.

Comparative Example 4 No nitrogen-containing compound was added,
170 parts of polyethylene 100 parts and carbamyl ammonium polyphosphate 20 parts using a Labo Plastomill
Kneading at a screw rotation speed of 60 RPM for 5 minutes, and then press-molded at 170 ° C. to a thickness of 0.4 mm.
The sheet was prepared, and the obtained sheet was irradiated with an electron beam at an accelerating voltage of 700 KV at 8.0 Mrad to prepare a crosslinked sheet having a crosslinking degree of 30%.

(Comparative Example 5) 100 parts of polypropylene, 5.0 parts of isocyanuric acid triacryloyl ester, 200 parts of ammonium polyphosphate and 0.8 part of benzoyl peroxide were used at 270 ° C. using a Labo Plastomill.
A kneaded material having a cross-linking degree of 40% was press-molded at 190 ° C. by kneading for 5 minutes under a screw rotation speed of 60 RPM to prepare a cross-linked sheet having a thickness of 0.4 mm.

Comparative Example 6 50 parts of polypropylene, 30 parts of polyethylene, 20 parts of poly (1-butene), 6.0 parts of cyanuric acid triallyl ester and 4.0 parts of polyphosphoric acid amide were used in a Labo Plastomill. A kneaded material having a degree of crosslinking of 38% was press-molded at 190 ° C. by kneading at 270 ° C. for 5 minutes under a screw rotation speed of 60 RPM to prepare a crosslinked sheet having a thickness of 0.4 mm.

(Comparative Example 7) 100 parts of polypropylene, 2.0 parts of cyanuric acid (tri) homoallyl ester and 90 parts of ammonium polyphosphate were used in a Labo Plastomill at 270 ° C. and a screw rotation speed of 60 RPM for 5 times.
By kneading for a minute, a kneaded product with a crosslinking degree of 26% is
Press molding was carried out at 0 ° C. to prepare a crosslinked sheet having a thickness of 0.4 mm.

The crosslinked sheets obtained in Examples 1 to 7 and Comparative Examples 1 to 7 were evaluated for flame retardancy and secondary workability based on JIS D1201, and the results are shown in Tables 1 and 2.

[0051]

[Table 1]

[0052]

[Table 2]

The evaluation of the secondary workability is conducted according to JIS standard K7.
Based on 113, a tensile test was conducted at room temperature and 170 ° C., and those showing an elongation of 200% or more at room temperature and 500% or more at 170 ° C. were evaluated as ◯, and those less than 500% were evaluated as x.

[0054]

Industrial Applicability The polyolefin flame-retardant crosslinkable resin composition of the present invention has the above-mentioned constitution and has remarkable flame retardancy and crosslinkability, and does not generate a halogen-based gas when burned. It is also excellent in secondary processability and does not require the addition of a cross-linking auxiliary agent for cross-linking, and can be used for foams, wire coatings, heat-shrinkable tubes and the like.

Claims (1)

[Claims] 1. 100 parts by weight of a polyolefin resin, 0.5 to 30 parts by weight of one or more nitrogen-containing compounds selected from the group consisting of the general formula (1) and the general formula (2), and the general formula (3). Polyphosphoric acid ester compound 3-1 represented by
A flame-retardant cross-linkable polyolefin resin composition, which comprises 100 parts by weight and has a weight ratio of the nitrogen-containing compound to the polyphosphate ester compound of 1:40 to 1: 1. [Chemical 1] R ¹ , R ² , and R ³ in the general formula (1) are groups selected from a hydrogen atom, an alkyl group, and a group having an ethylenic double bond at the terminal, and at least one is ethylenic at the terminal. It is a group having a double bond, and R ¹ , R ² and R ³ may be the same or different. ] [Chemical 2] [R ⁴ , R ⁵ , and R ⁶ in the general formula (2) are groups selected from a hydrogen atom, an alkyl group, and a group having an ethylenic double bond at the terminal, and at least one is ethylene at the terminal. And R ⁴ , R ⁵ and R ⁶ may be the same or different. ] [Chemical 3] [N in general formula (3) is a natural number of 20 or more,
R ⁷ , R ⁸ and R ⁹ are H, NH ₄ or CONH ₂ ,
They may be the same or different. However, R ⁷ , R
⁸ and R ⁹ are not H or CONH ₂ at the same time. )