JPH11171936A - Flame-retardant polyolefin resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame-retarded polyolefin resin without using a halogen- containing compound as the flame-retardant. SOLUTION: This flame-retardant polyolefin resin contains 0.01-1 unit of a phosphoric acid compound having C=C double bond and grafted to 1 unit of the monomer constituting a polyolefin resin. The phosphoric acid compound is one or more compounds selected from phosphoric acid esters, phosphonic acid derivatives, phosphonic acid esters, phosphinic acid derivatives, phosphinic acid esters, vinylphosphonic acid, vinylphosphonic acid diethyl ester, 2- acryloyloxyethylphosphonic acid, 2-methacryloyloxyethylphosphonic acid and bis(2-methacryloyloxyethyl)phosphonic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a flame-retardant polyolefin resin.

[0002]

2. Description of the Related Art Many polyolefin resins are inherently flammable resins, and with the expansion of applications in recent years, it has been strongly required that they be flame retardant materials. Is being processed. As a method of making a polyolefin resin flame-retardant, a method of adding a halogen-containing compound is generally employed.

[0003] However, the above-mentioned flame-retarding method may generate a large amount of halogen-based gas at the time of molding or burning, and the generated gas may corrode equipment or affect the human body. In view of the properties, there is a strong demand for a halogen-free flame retarding treatment method that does not use a halogen-containing compound.

[0004] As one of the non-halogen flame retardant techniques for polyolefin resins, a hydrated metal compound, a phosphorus-based flame retardant, etc. are added to the resin to cool the dehydration reaction during combustion,
There has been proposed a method utilizing an oxygen barrier effect or the like by forming a surface film. However, this method is to impart sufficient flame retardancy to the flammable polyolefin resin,
It is necessary to add a large amount of a hydrated metal compound, a phosphorus-based flame retardant, and the like. As a result, there is a problem that the mechanical strength of the obtained molded article is significantly reduced, and it is difficult to put the molded article to practical use.

Furthermore, a method has been reported in which a compound having a flame retardant effect is graft-reacted to a polyolefin-based resin, thereby making the resin flame-retardant with a relatively small amount of introduction [M. Banks et al. , Polymer, 3
4,4547 (1993)]. For example, Banks et al. Oxidize phosphorus trichloride on low-density polyethylene (LDPE) and then hydrolyze to graft a phosphonyl group to improve flame retardancy.

However, in this method, even if phosphorus trichloride is used in a large excess, it is difficult to impart sufficient flame retardancy due to a small amount of phosphonyl group introduced. Further, phosphorus trichloride is not preferable from the viewpoint of production because it is easily hydrolyzed and difficult to handle. Furthermore, when the phosphorus trichloride is not sufficiently hydrolyzed, chlorine may remain in the product, and it cannot be said that the treatment is completely non-halogen flame retardant.

[0007]

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a polyolefin resin having excellent flame retardancy by a halogen-free flame retarding treatment.

[0008]

The flame-retardant polyolefin resin of the present invention comprises a phosphoric acid compound having a carbon-carbon double bond in an amount of 0.01 to 1 unit of a monomer unit constituting the polyolefin resin. One unit is obtained by a graft reaction.

Examples of the polyolefin resin used in the present invention include polyethylene resin, polypropylene resin, poly (1-butene) resin, polypentene resin and the like.

The polyethylene resin may be any one of ethylene homopolymer (low density, medium density, high density), a copolymer containing ethylene as a main component, and a mixture thereof. Examples of the copolymer include an ethylene-α-olefin copolymer containing ethylene as a main component. As the α-olefin, propylene, 1-
Hexene, 4-methyl-1-pentene, 1-octene,
Examples thereof include 1-butene and 1-pentene. Further, as the copolymer other than the α-olefin, an ethylene-vinyl acetate copolymer or an ethylene-ethyl acrylate copolymer may be used.

The polypropylene resin may be any of a propylene homopolymer, a propylene-based copolymer, and a mixture thereof. Examples of the copolymer include a propylene-α-olefin copolymer containing propylene as a main component. Examples of the α-olefin include ethylene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-butene, 1-pentene and the like.

The phosphate compound used in the present invention is preferably a compound having at least one carbon-carbon double bond and having at least one P-OH or P-O-C bond. The valence may be any. The carbon-carbon double bond in the phosphate compound serves as a reaction point with the polyolefin resin in the graft reaction.

The P-OH or P-O-C bond causes a condensation reaction during combustion to form polymetaphosphoric acid, which acts as a non-combustible film to exhibit an effect such as blocking oxygen, thereby exhibiting flame retardancy. In the present invention, the flame retardation due to the grafting of the phosphoric acid-based compound causes a chemical bond between the flame retardant and the resin, so that a combustion residue remains as a composite of the flame retardant and the resin during combustion, and the flame retardancy is improved. As a result, it is possible to improve the flame retardancy with a small amount of addition as compared with the case where the phosphoric acid compound is simply added.

The above-mentioned phosphoric acid compound has a general formula (1)
It may be one or more compounds selected from phosphate esters, phosphonic acid derivatives, phosphonic acid esters, phosphinic acid derivatives, phosphinic acid esters, and phosphite esters represented by (6).

[0015]

Embedded image

In the formula, R ^{1 to} R ³ represent a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be the same or different. Further, any one of R ^{1 to} R ³ has a carbon-carbon double bond.

The number of carbon atoms of the aliphatic or aromatic hydrocarbon group is preferably 1 to 20, since the flame retardancy of the grafted resin decreases as the number of carbon atoms increases. Further, the position of the carbon-carbon double bond of the aliphatic or aromatic hydrocarbon group may be any position as long as the graft reaction occurs, but the terminal is preferable.

Examples of the phosphate (1) include vinyl phosphate, allyl phosphate, butenyl phosphate,
Examples include vinylphenyl phosphate, divinyl phosphate, diallyl phosphate, dibutenyl phosphate, bis (vinylphenyl) phosphate, trivinyl phosphate, triallyl phosphate, tributenyl phosphate, and tris (vinylphenyl) phosphate.

The phosphonic acid derivative (2) includes, for example, vinylphosphonic acid, allylphosphonic acid, butenylphosphonic acid, vinylphenylphosphonic acid, 2-acryloyloxyethylphosphonic acid, 2-methacryloxyethylphosphonic acid, (2-methacryloxyethyl) phosphonic acid and the like.

The phosphonic acid ester (3) includes:
For example, monomethyl ester of vinyl phosphonic acid, monoethyl ester of vinyl phosphonic acid, monophenyl ester of vinyl phosphonic acid, dimethyl ester of vinyl phosphonic acid, diethyl ester of vinyl phosphonic acid, diphenyl ester of vinyl phosphonic acid, monomethyl ester of allyl phosphonic acid, monomethyl allyl phosphonic acid Ethyl ester, allylphosphonic acid monophenyl ester, allylphosphonic acid dimethyl ester, allylphosphonic acid diethyl ester, allylphosphonic acid diphenyl ester, butenylphosphonic monomethyl ester, butenylphosphonic monoethyl ester, butenylphosphonic monophenyl ester, butenylphosphonic dimethyl ester, Butenyl phosphonic acid diethyl ester, butenyl phosphonic acid diphenyl ester, vinyl Phenylphosphonic acid monomethyl ester, vinyl phenyl phosphonic acid monoethyl ester, vinyl phenyl phosphonic acid monophenyl ester,
Vinylphenylphosphonic acid dimethyl ester, vinylphenylphosphonic acid diethyl ester, vinylphenylphosphonic acid diphenyl ester, methylphosphonic monovinyl ester, methylphosphonic monoallyl ester,
Methylphosphonic acid monobutenyl ester, methylphosphonic acid monovinylphenyl ester, methylphosphonic acid divinyl ester, methylphosphonic acid diallyl ester,
Methylphosphonic acid dibutenyl ester, methylphosphonic acid bis (vinylphenyl) ester, ethylphosphonic monovinyl ester, ethylphosphonic monoallyl ester, ethylphosphonic monobutenyl ester, ethylphosphonic monovinylphenyl ester, ethylphosphonic divinyl ester, ethyl Diallyl phosphonate, dibutenyl ethyl phosphonate, bis (vinyl phenyl) ethyl phosphonate, monovinyl phenyl phosphonate, monoallyl phenyl phosphonate, monobutenyl phenyl phosphonate, monovinyl phenyl phenyl phosphonate, Phenylphosphonic acid divinyl ester, phenylphosphonic acid diallyl ester, phenylphosphonic acid dibutenyl ester, Ruhosuhon acid bis (vinylphenyl) esters.

The phosphinic acid derivative (4) includes
For example, vinyl phosphinic acid, allyl phosphinic acid, butenyl phosphinic acid, vinyl phenyl phosphinic acid, divinyl phosphinic acid, diallyl phosphinic acid, dibutenyl phosphinic acid, bis (vinyl phenyl) phosphinic acid and the like can be mentioned.

Examples of the phosphinic acid ester (5) include vinyl phosphinic acid methyl ester, vinyl phosphinic acid ethyl ester, vinyl phosphinic acid phenyl ester, allyl phosphinic acid methyl ester,
Allyl phosphinic acid ethyl ester, allyl phosphinic acid phenyl ester, butenyl phosphinic acid methyl ester, butenyl phosphinic acid ethyl ester, butenyl phosphinic acid phenyl ester, vinyl phenyl phosphinic acid methyl ester, vinyl phenyl phosphinic acid ethyl ester, vinyl phenyl phosphine Acid phenyl ester, divinyl phosphinic acid methyl ester, divinyl phosphinic acid ethyl ester, divinyl phosphinic acid phenyl ester, diallyl phosphinic acid methyl ester, diallyl phosphinic acid ethyl ester, diallyl phosphinic acid phenyl ester, dibutenyl phosphinic acid methyl ester, dibutenyl phosphine Acid ethyl ester, dibutenylphosphinic acid phenyl ester, bis (vinylphenyl) Sufin acid methyl ester, bis (vinylphenyl) phosphinic acid ethyl ester, screws or the like (vinylphenyl) phosphinic acid phenyl ester.

Examples of the phosphite (6) include vinyl phosphite, allyl phosphite, butenyl phosphite, vinyl phenyl phosphite, divinyl phosphite, diallyl phosphite, and phosphorous acid Dibutenyl, bis (vinylphenyl) phosphite, trivinyl phosphite, triallyl phosphite, tributenyl phosphite, tris (vinylphenyl) phosphite and the like.

Of the above phosphoric acid compounds, vinylphosphonic acid and dimethyl vinylphosphonate exhibit an extremely high flame-retardant effect because of their low content of organic components. Also, 2-acryloyloxyethylphosphonic acid, 2
-Methacryloxyethylphosphonic acid and bis (2-methacryloxyethyl) phosphonic acid contain a carboxyl group in the molecule and generate incombustible carbon dioxide gas during combustion to improve flame retardancy. These phosphate compounds are
It has high graft reactivity and can be easily introduced into a resin.

The flame-retardant polyolefin resin of the present invention comprises:
In the presence of the above-mentioned phosphate compound in the presence of a radical polymerization initiator,
It is obtained by performing a graft reaction with heat, light or an electron beam. As the production method, polyolefin resin,
After the phosphoric acid compound and the radical polymerization initiator are melt-kneaded, they are grafted by heat, light or an electron beam.

When the amount of the phosphoric acid-based compound used is small, the flame-retardant effect is small. When the amount is large, the compound is left in the resin without graft reaction, and the mechanical strength and mechanical strength are reduced. Is a phosphoric acid-based compound in an amount of 0.01 to 1 relative to 1 unit of the monomer unit constituting
Is a unit.

Examples of the radical polymerization initiator include dicumyl peroxide and 2,5-dimethyl-2,5
Dialkyl peroxides such as -dibutyl-peroxyhexyne-3-t-butyl peroxide, 2,5-dimethyl-2,5-t-butyl peroxide and 1,3-bis (t-butylperoxyisopropyl) benzene ; 2,2
Peroxy ketals such as -di-t-butylperoxybutane; diacyl peroxides such as dibenzoyl peroxide and bis (o-chlorobenzoyl) peroxide; t
Alkyl peresters such as -butylperoxybenzoate.

When the amount of the radical polymerization initiator used is small, the grafting reaction does not proceed efficiently, and when the amount is large, the deterioration of the resin is promoted. 5 moles are preferred.

The above-mentioned graft reaction by heat is preferably carried out successively after melt-kneading. In the case of electron beam treatment, a radical polymerization initiator may not be used.

The reaction conditions for the above-described graft reaction by heat vary depending on the melting point and the deterioration temperature of the resin, the boiling point of the phosphate compound, and the decomposition temperature of the radical polymerization initiator.
When the temperature is low or the time is short, the grafting reaction does not proceed sufficiently, and when the temperature is high or the time is long, a degradation reaction of the resin occurs.
C. and the reaction time is preferably 1 minute to 1 hour.

In the case of the above-described graft reaction by light, ultraviolet irradiation is performed. When the irradiation amount of the ultraviolet ray is small, the grafting reaction does not sufficiently proceed, and when the irradiation amount is large, the degradation reaction of the resin occurs. Therefore, the irradiation amount is preferably, for example, 50 to 5,000 mJ / cm ² as the integrated exposure amount at 365 nm.

As the light source used for the ultraviolet irradiation, for example, a high-pressure mercury lamp, a halogen lamp, a xenon lamp, a nitrogen laser, a He—Cd laser, an Ar laser and the like are used.

In the case of the above-mentioned grafting reaction by electron beam, when the irradiation amount of the electron beam is small, the grafting reaction does not proceed sufficiently, and when the irradiation amount is large, the degradation reaction of the resin occurs. .

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 5 Polyethylene resin (manufactured by Mitsubishi Chemical Corporation, density: 0.92 g / cm ³ , MI = 3.
4) 100 parts by weight, 15 parts by weight of the phosphoric acid compound shown in Table 1, and a radical polymerization initiator ("Perhexin 25B" manufactured by NOF Corporation, component: 2,5-dimethyl-2,5-dibutyl-peroxyhexine) 1 part by weight of tert-butyl peroxide) was supplied to a Labo Plastomill at 180 ° C. in this order, melted and kneaded, and subsequently kneaded at 180 ° C. for 4 minutes to carry out a graft reaction to obtain a flame-retardant polyethylene-based resin. A resin was obtained.

(Comparative Examples 1 to 5) A flame-retardant polyethylene resin was obtained in the same manner as in Examples 1 to 5, except that no radical polymerization initiator was used.

(Comparative Example 6) Reference [M. Banks et
al. , Polymer, 34, 4547 (199).
3) According to the method described in [3], a flame-retardant polyethylene resin was obtained by grafting a phosphonyl group with phosphorus trichloride (manufactured by Wako Pure Chemical Industries, Ltd.). The amount of phosphorus trichloride was as shown in Table 1.

The flame-retardant polyethylene resins obtained in the above Examples and Comparative Examples were melt-compressed at 180 ° C. to produce plate-like products. From the obtained plate-like material, JIS K72
According to No. 01, the oxygen index of a test piece A-1 (length 150 mm, width 6.5 mm, thickness 3 mm) was measured. ×, shown in Table 1.

[0039]

[Table 1]

In the table, the amount of the phosphoric acid compound introduced is the number of units of the phosphoric acid compound which has been graft-reacted with respect to one unit of the monomer unit constituting the polyethylene resin.

When Examples 1 to 5 and Comparative Examples 1 to 5 are compared, a phosphoric acid compound is graft-reacted.
It can be seen that excellent flame retardancy is provided. When Examples 1 to 5 and Comparative Example 6 were compared, all of the Examples were excellent in flame retardancy, and the method of the present invention was more effective than the method of Comparative Example 6 in which a phosphonyl group was graft-reacted. Can be increased, so that it is presumed that a more excellent flame retardant effect is given.

[0042]

The polyolefin resin of the present invention has the above-mentioned structure, has excellent flame retardancy, and can be easily produced without generating a halogen-based gas at the time of combustion or molding. It can be used for a wide range of applications requiring flame retardancy.

Claims (3)

[Claims] 1. A flame-retardant polyolefin-based resin obtained by grafting 0.01 to 1 unit of a phosphoric acid-based compound having a carbon-carbon double bond to 1 unit of a monomer unit constituting the polyolefin-based resin. 2. The method according to claim 1, wherein the phosphoric acid compound is at least one compound selected from a phosphoric acid ester, a phosphonic acid derivative, a phosphonic acid ester, a phosphinic acid derivative, a phosphinic acid ester, and a phosphite ester. The flame-retardant polyolefin resin according to claim 1. 3. The phosphoric acid compound is vinylphosphonic acid, vinylphosphonic acid diethyl ester, 2-acryloyloxyethylphosphonic acid, 2-methacryloxyethylphosphonic acid, and bis (2-methacryloxyethyl). The flame-retardant polyolefin-based resin according to claim 1, which is at least one compound selected from phosphonic acids.