JP2901736B2 - Method for producing modified polyolefin particles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing modified polyolefin particles. More specifically, the present invention relates to a novel method for producing particulate modified polyolefin using polyolefin particles oxidized in the gas phase.

Technical Background of the Invention Various methods have conventionally been proposed as a method for modifying a polyolefin with an ethylenically unsaturated group-containing monomer such as styrene.

For example, after a polyolefin is irradiated with an energy beam such as an electron beam, the polyolefin and the ethylenically unsaturated group-containing monomer are dissolved in an organic solvent by a method in which the polyolefin is contacted with an ethylenically unsaturated group-containing monomer. A method of performing a reaction in the presence of an oxide, a method of reacting an ethylenically unsaturated group-containing monomer with a polyolefin in a molten state such as a kneading apparatus, and the like are known.

Under such a technical background, when a modified polyolefin is produced by reacting a polyolefin with a vinyl monomer, as a polyolefin, a polyolefin in a dispersion in which the polyolefin is dispersed in an aqueous solvent is formed using an organic peroxide. It has been proposed to use an oxidized polyolefin prepared by oxidation (see JP-A-58-93730). By pre-oxidizing the polyolefin in this way, it becomes easier to introduce a vinyl monomer.

However, in this method, the oxidation reaction is performed in a water solvent, and it is necessary to considerably increase the oxygen concentration in the water solvent in order to efficiently perform the oxidation reaction. Therefore,
In this method, it is necessary to use a pressure-resistant reactor such as an autoclave, which is disadvantageous in terms of equipment, and it is actually quite difficult to perform a continuous oxidation reaction using such a device. There is also a problem in workability.

OBJECTS OF THE INVENTION An object of the present invention is to provide a novel method for modifying polyolefin particles with an ethylenically unsaturated group-containing monomer.

More specifically, the present invention relates to a molded article in which polyolefin particles are efficiently modified with an ethylenically unsaturated group-containing monomer, the uniformity is high, the mechanical properties such as impact resistance are excellent, and the surface appearance is good. It is an object of the present invention to provide a novel method for producing modified polyolefin particles that can be made into the following.

SUMMARY OF THE INVENTION A method for producing a modified polyolefin particle according to the present invention comprises:
The gas phase oxidation-treated polyolefin particles (A) and the ethylenically unsaturated group-containing monomer (B) are mixed in the presence of a reducing substance (C), and the polyolefin particles (A) are mixed.
Is characterized by heating under an inert gas phase condition capable of substantially maintaining the particle shape.

In the present invention, when preparing modified polyolefin particles as described above, polyolefin particles (A) oxidized in the gas phase are used. By oxidizing the polyolefin particles in the gas phase in this way, the oxidizing treatment can be performed without using a reaction device such as an autoclave which requires extremely high pressure resistance. Moreover, in the present invention, both the oxidation treatment step and the modification step following the oxidation treatment step are performed in the gas phase, so that both steps can be performed continuously.

Further, in the present invention, since the polyolefin particles (A) oxidized in the gas phase are modified in the presence of the reducing substance (C), modified polyolefin particles can be efficiently produced.

Furthermore, by blending the modified polyolefin particles thus obtained with another resin, a molded article having excellent mechanical properties such as impact resistance can be prepared.

Next, the method for producing the modified polyolefin particles of the present invention will be specifically described.

In the method for producing modified polyolefin particles of the present invention, the gas-phase oxidized polyolefin particles (A)
The ethylenically unsaturated group-containing monomer (B) is mixed in the presence of the reducing substance (C).

The method for producing polyolefin particles (hereinafter sometimes referred to as “unoxidized polyolefin particles”) used for preparing the polyolefin particles (A) subjected to the gas phase oxidation treatment is not particularly limited, but is described below. It is preferable to adopt a method that employs such a method.

That is, the unoxidized polyolefin particles can be obtained by, for example, polymerizing or copolymerizing an α-olefin having 2 to 20 carbon atoms.

Examples of such α-olefins include ethylene,
Propylene, butene-1, pentene-1, 2-methylbutene-1, 3-methylbutene-1, hexene-1, 3-
Methylpentene-1,4-methylpentene-1,3,3-
Dimethylpentene-1, heptene-1, methylhexene-1, dimethylpentene-1, trimethylbutene-1,
Ethylpentene-1, octene-1, methylpentene
1, dimethylhexene-1, trimethylpentene-1,
Ethylhexene-1, methylethylpentene-1, diethylbutene-1, propylpentene-1, decene-1,
Α-olefins such as methylnonene-1, dimethyloctene-1, trimethylheptene-1, ethyloctene-1, methylethylheptene-1, diethylhexene-1, dodecene-1 and hexadodecene-1 can be mentioned. .

Among these, it is preferable to use an α-olefin having 2 to 8 carbon atoms alone or in combination,
It is particularly preferred to use a combination of ethylene and propylene.

The unoxidized polyolefin particles contain a repeating unit derived from the above α-olefin, usually at least 50 mol%,
The content is preferably 80 mol% or more, particularly preferably 100 mol%.

Further, the polyolefin particles have the α
-Besides the repeating units derived from olefins, this α
-It may have a repeating unit derived from another compound polymerizable with the olefin.

Other compounds used herein include, for example, chain polyene compounds and cyclic polyene compounds.

These polyene compounds are polyenes having two or more conjugated or non-conjugated olefinic double bonds,
Examples of such chain polyene compounds include 1,4-hexadiene, 1,5-hexadiene, 1,7-octadiene,
Examples thereof include 1,9-decadiene, 2,4,6-octatriene, 1,3,7-octatriene, 1,5,9-decatriene and divinylbenzene.

Examples of the cyclic polyene compound include 1,3-cyclopentadiene, 1,3-cyclohexadiene, 5-ethyl-1,3-cyclohexadiene, 1,3-cycloheptadiene, dicyclopentadiene, and dicyclohexadiene. , 5
-Ethylidene-2-norbornene, 5-methylene-2-
Norbornene, 5-vinyl-2-norbornene, 5-isopropylidene-2-norbornene, methylhydroindene, 2,3-diisopropylidene-5-norbornene,
Examples include 2-ethylidene-3-isopropylidene-5-norbornene and 2-propenyl-2,5-norbornadiene.

Furthermore, in producing the above-mentioned unoxidized polyolefin particles, a cyclic monoene can be used,
Examples of such cyclic monoenes are cyclopropene, cyclobutene, cyclopentene, cyclohexene,
Monocycloalkenes such as 3-methylcyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclododecene, tetracyclodecene, octacyclodecene and cycloeicosene; norbornene, 5-methyl-2-norbornene, 5-
Ethyl-2-norbornene, 5-isobutyl-2-norbornene, 5,6-dimethyl-2-norbornene, 5,5,6-
Trimethyl-2-norbornene and bicycloalkene of 2-bornene name; 2,3,3a, 7a-tetrahydro-4,7-
Tricycloalkenes such as methano-1H-indene and 3a, 5,6,7a-tetrahydro-4,7-methano-1H-indene; 1,4,5,8-dimethano-1,2,3,4,4a , 5,8,8a-Octahydronaphthalene and, in addition to these compounds, 2-methyl-1,4,5,8-dimetano-1,2,3,4,4a, 5,8,8a-octa Hydronaphthalene, 2-ethyl-1,4,5,8-dimethano-
1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-propyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a- Octahydronaphthalene, 2-hexyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2
-Stearyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a
-Octahydronaphthalene, 2,3-dimethyl-1,4,5,8-
Dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-methyl-3-ethyl-1,4,5,8-dimethano-1,
2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-chloro-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydro Naphthalene, 2-bromo-1,4,5,8-dimethano-1,
2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-fluoro-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydro Tetracycloalkenes such as naphthalene and 2,3-dichloro-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene; hexacyclo [6,6,1 , 1 ^3.6 , 1 ^10.13 , 0 ^2.7 , 0 ^9.14 ]
Heptadecene -4, pentacyclo [8,8,1 ^2.9, 1 ^4.7, 1
^11.18, 0,0 ^3.8, 0 ^12.17] heneicosene -5, octacyclo [8,8,1 ^2.9, 1 ^4.7, 1 ^11.18, 1 ^13.16, 0,0 ^3.8,
12.17 ] Cyclic monoene compounds such as polycycloalkenes such as dococene-5.

Furthermore, in producing the above-mentioned unoxidized polyolefin particles, styrene and substituted styrene can be used.

The unoxidized polyolefin particles are obtained, for example, by polymerizing or copolymerizing the above-mentioned α-olefin in the presence of a catalyst. This polymerization reaction or copolymerization reaction can be carried out in a gas phase (gas phase method) or in a liquid phase (liquid phase method).

The polymerization reaction or copolymerization reaction by the liquid phase method is preferably performed in a suspended state so that the polyolefin particles to be produced can be obtained in a solid state.

As a solvent used in the polymerization reaction or the copolymerization reaction, an inert hydrocarbon can be used.
Further, an α-olefin as a raw material may be used as a reaction solvent.

In producing the above-mentioned unoxidized polyolefin particles, the above-mentioned polymerization or copolymerization employs a gas phase method, or a method in which a reaction is performed in a liquid phase using an α-olefin as a solvent, and then the gas phase method is combined. Or the like.

In the method in which the liquid phase method and the gas phase method are combined, an inert hydrocarbon or an α-olefin as a raw material is used as a reaction solvent, and after the α-olefin is prepolymerized in the presence of a specific catalyst, the gas is vaporized. The α-olefin is further polymerized in the phase.

Examples of the inert hydrocarbon used in the solvent include propane, butane, n-pentane, i-pentane,
Aliphatic hydrocarbons such as n-hexane, i-hexane, n-heptane, n-octane, i-octane, n-decane, n-dodecane and kerosene; fats such as cyclopentane, methylcyclopentane, cyclohexane and methylcyclohexane Cyclic hydrocarbons; aromatic hydrocarbons such as benzene, toluene and xylene; and halogenated hydrocarbon compounds such as methylene chloride, ethylene chloride and chlorobenzene.

Further, as the above-mentioned catalyst, preferably, a catalyst component containing a transition metal of Groups IVA, VA, VIA, VIIA and VIII of the Periodic Table of the Elements, for example, titanium, zirconium, hafnium, vanadium. [A] and a group I, II and III of the Periodic Table of the Elements, such as organoaluminum compounds having at least one Al-carbon bond in the molecule.
A catalyst comprising a group III organometallic compound catalyst component [B] is used.

The catalyst component [A] can be prepared by blending an electron donor [C] (inside donor) in addition to the above components.

Examples of the catalyst component [A] include Periodic Table IVA
Group, a catalyst containing a transition metal atom of group VA,
Among these, a catalyst component containing at least one atom selected from the group consisting of titanium, zirconium, hafnium and vanadium is particularly preferred.

Further, as another preferred catalyst component [A], a catalyst component containing a halogen atom and a magnesium atom in addition to the above-mentioned transition metal atom, a conjugated electron to a transition metal atom belonging to Group IVA or VA of Periodic Table IV. And a catalyst component containing a compound having a group coordinated thereto.

The catalyst component [A] used in the production of the unoxidized polyolefin particles may be present in a solid state in the reaction system during the polymerization reaction or the copolymerization reaction as described above, or may be supported on a carrier or the like. It is preferred to use a catalyst which has been prepared so that it can be present in the solid state.

Such a catalyst component [A] is disclosed in JP-A-55-135.
No. 102, No. 55-135103, No. 56-67311 and Japanese Patent Application No.
Nos. 56-181019 and 61-21109.

Examples of the organometallic compound catalyst component [B] used together with the catalyst component [A] in producing the unoxidized polyolefin particles include aluminoxane,
An organoaluminum compound obtained by reacting an organoaluminum compound with water, or an organoaluminum compound obtained by reacting an aluminoxane solution with water or an active hydrogen-containing compound can be used.

The organometallic compound catalyst component [B] may further contain an electron donor [C] (outside donor) in addition to the above components.

In preparing the unoxidized polyolefin particles, a prepolymerization is carried out prior to the main polymerization using the above catalyst.

After the preliminary polymerization, the above-mentioned unoxidized polyolefin particles can be prepared by performing main polymerization in a gas phase. The polymerization temperature at the time of the prepolymerization is usually -40 to 80 ° C, and the polymerization temperature at the time of the main polymerization using the catalyst as described above is usually -50 to 20 ° C, and the pressure is normal pressure to 100 kg /. The polymerization is carried out within a range of cm ² .

In the method for producing such unoxidized polyolefin particles, the technique described in Japanese Patent Application No. 63-294066 can be used.

For example, the unoxidized polyolefin particles produced as described above usually have a particle form in which crystal parts and amorphous parts are distributed in a sea-island manner. Furthermore, the crystal part is made of a crystalline polyolefin, particularly a polypropylene-based resin, and the amorphous part is suitable for forming a molded article excellent in impact resistance by using polyolefin particles made of an ethylene propylene random copolymer rubber. Thus, modified polyolefin particles can be obtained.

For example, the melt flow rate measured at 230 ° C. according to ASTM D 1238 of the unoxidized treated polyolefin particles prepared as described above is usually in the range of 0.1 to 100 g / 10 minutes, preferably 1 to 50 g / 10 minutes. It is in.

Further, the average particle diameter is usually 10 to 5000 μm, preferably
It is in the range from 100 to 4000 μm, particularly preferably from 300 to 3000 μm. Further, the geometric standard deviation indicating the particle size distribution of the unoxidized polyolefin particles is usually 1.0 to 2.0,
It is preferably in the range of 1.0 to 1.5, particularly preferably 1.0 to 1.3.

The apparent bulk density of the polyolefin particles due to natural fall is usually 0.20 g / cm ³ or more, preferably 0.30 to 0.7.
0 g / cm ^3, particularly preferably in the range of 0.35~0.60g / cm ^3.

In the unoxidized polyolefin particles produced by employing the above method, the transition metal component is usually 100 ppm.
Or less, preferably 10 ppm or less, particularly preferably 5 ppm or less, the halogen content is usually 300 ppm or less, preferably 10 ppm or less.
The content is 0 ppm or less, particularly preferably 50 ppm or less.

In the production method of the present invention, the above-mentioned unoxidized polyolefin particles which have been oxidized in the gas phase are used.

This oxidation treatment is performed by adding an organic peroxide to the above-described unoxidized treated polyolefin particles, mixing them sufficiently, and then heating to a temperature equal to or higher than the decomposition temperature of the organic peroxide in the presence of oxygen. . In the present invention, such an oxidation treatment is performed in a gas phase.

Examples of organic peroxides in the above mixture used in the present invention include dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5
-Dimethyl-2,5-bis (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) bararate, dibenzoyl peroxide, tert-butylperoxybenzoate, tert -Butylperoxy-2-ethylhexanoate, cyclohexanone peroxide, 2,5-dimethyl-2,5-dibenzoylperoxyhexane, tert-butylperoxybenzoate, di-
tert-butyl-diperoxyphthalate, methyl ethyl ketone peroxide and the like.

Such an organic peroxide is usually 0.001 to 10 parts by weight based on 100 parts by weight of the polyolefin particles to be oxidized.
It is used in a proportion by weight, preferably 0.01 to 5 parts by weight.

Such an organic peroxide can be used as it is mixed with the polyolefin particles, but can also be used by dissolving the organic peroxide in a small amount of an organic solvent. As the organic solvent used here, any organic solvent that can dissolve the organic peroxide can be used without particular limitation. Examples of such an organic solvent include aromatic hydrocarbon solvents such as benzene, toluene and xylene, aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, nonane, and decane; cyclohexane, methylcyclohexane, and decahydronaphthalene. Alicyclic hydrocarbon solvents such as chlorobenzene, dichlorobenzene, trichlorobenzene, methylene chloride, chloroform, carbon tetrachloride, chlorinated hydrocarbons such as tetrachloroethylene, methanol, ethanol, n-propynol, is
o-propanol, n-butanol, sec-butanol,
alcohol solvents such as tert-butanol; ketone solvents such as fusetone, methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as acetic acid, ethyl and dimethyl phthalate; dimethyl ether, diethyl ether and di-
Ether solvents such as n-amyl ether, tetrahydrofuran and dioxyanisole can be mentioned, and toluene, xylene and acetone are preferably used. These solvents can be used alone or as a mixture.

In preparing the oxidized polyolefin particles (A), it is preferable to carry out the reaction so that the above-mentioned unoxidized polyolefin particles do not impair the particle state, and thus used for dissolving the organic peroxide. The organic solvent is used in an amount of usually 0.1 to 30 parts by weight, preferably 1 to 20 parts by weight, based on 100 parts by weight of the polyolefin.

If organic solvents having a high affinity for polyolefins such as aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, and chlorinated hydrocarbons are used, these solvents penetrate into the polyolefin particles and become particles. Swells somewhat and acts to spread the organic peroxide into the particles.

In preparing the oxidized polyolefin particles (A), the polyolefin particles and the organic peroxide are sufficiently mixed and used.

In the preparation of the oxidized polyolefin particles (A), the mixture of the unoxidized polyolefin particles prepared as described above and an organic peroxide is heated to a temperature not lower than the decomposition temperature of the organic peroxide, preferably The heating is performed at a temperature not lower than the decomposition temperature and not higher than the temperature at which the unoxidized polyolefin particles are melted. Specifically, the heating temperature of this oxidation treatment is usually 50 to 140 ° C, preferably 60 ° C.
~ 120 ° C.

This oxidation treatment needs to be performed in a gas phase, and is usually performed in air. Therefore, in the present invention, a dispersion medium for polyolefin particles such as an aqueous dispersion medium is not used.

Under the above temperature conditions, the time required for the vapor phase oxidation treatment is usually 0.5 to 15 hours.

In the present invention, the gas phase oxidation treatment of the unoxidized polyolefin particles does not need to be particularly performed under pressure, so that the reaction device is a mixture of the unoxidized polyolefin particles and the organic peroxide. There is no particular limitation on the shape and the like of the device as long as it can be heated to the above temperature, and various heating devices can be used. Especially when it is performed continuously, fluidized beds, moving beds, loop reactors,
It is preferable to use a continuous heating device such as a paddle dryer.

As described above, the gas phase oxidation treatment of the unoxidized polyolefin particles has only an advantage that the oxidation treatment of the unoxidized polyolefin particles can be continuously performed without using a complicated apparatus. Instead, the oxidation treatment can be performed very uniformly. That is, by performing the oxidation treatment in the gas phase, the difference between the degree of the treatment on the surface of the unoxidized treated polyolefin particles and the degree of the treatment in the deep part is reduced.

Incidentally, by performing the gas phase oxidation treatment of the unoxidized polyolefin particles having a crystal part and an amorphous part as described above, when a polar group is selectively formed in the amorphous part rather than the crystal part. Conceivable.

By performing the gas phase oxidation treatment as described above, ASTM D 1238 of the oxidized polyolefin particles (A) is obtained.
Melt flow rate measured at 230 ° C according to
It is in the range of 0.1 to 500 g / 10 minutes, preferably 1 to 100 g / 10 minutes.

Further, the average particle size, geometric standard deviation, apparent bulk density, and the like of the polyolefin particles do not substantially fluctuate by the gas phase oxidation treatment.

In the production method of the present invention, the oxidized polyolefin particles (A) prepared as described above and an ethylenically unsaturated group-containing monomer (B) are mixed in the presence of a reducing substance (C). Then, modified polyolefin particles are obtained by reacting under conditions that the particle state of the oxidized polyolefin particles (A) is substantially maintained.

The ethylenically unsaturated group-containing monomer (B) used in the present invention is an ethylenically unsaturated group, that is, a monomer having an unsaturated group copolymerizable with an α-olefin such as ethylene, Specific examples include styrene-based monomers, unsaturated carboxylic acids or derivatives thereof, acrylonitrile, vinyl acetate, vinyl chloride, and the like.

The styrenic monomer used in the present invention can be represented by the following formula [I].

In the formula [I], R ¹ and R ² each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and specifically, a methyl group, an ethyl group, a propyl group, and an isopropyl group. Can be mentioned. R ³ represents a hydrocarbon group having 1 to ³ carbon atoms or a halogen atom. Specific examples include a methyl group, an ethyl group, a propyl group and an isopropyl group, and a chlorine atom, a bromine atom and an iodine atom. Can be. N is 1 to 5
Represents an integer.

The styrene monomers can be used alone or in combination.

Specific examples of such a styrene monomer include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, o-chlorostyrene, p-chlorostyrene, and m-chlorostyrene. And p-chloromethylstyrene. In the present invention, among the styrene monomers represented by the above formula [I], styrene and α-methylstyrene are particularly preferable.

Examples of unsaturated carboxylic acids include acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid and nadic acid (endocis-bicyclo [2,2,1] hept-5 -Ene-2,3-dicarboxylic acid). Further, examples of the derivative of the unsaturated carboxylic acid include unsaturated carboxylic anhydride, unsaturated carboxylic halide, unsaturated carboxylic amide, unsaturated carboxylic imide and unsaturated carboxylic ester compound. Specific examples of such derivatives include maleenyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate and glycidyl maleate, and methyl methacrylate.

These unsaturated carboxylic acids and derivatives thereof can be used alone or in combination.

Among the above unsaturated carboxylic acids and derivatives thereof, unsaturated dicarboxylic acids or acid anhydrides thereof, or unsaturated carboxylic acid esters are preferable, and furthermore, maleic acid, nadic acid or acid anhydrides thereof, methyl methacrylate Is particularly preferred.

As such an ethylenically unsaturated group-containing monomer,
Two or more types having different classifications can be used in combination.

The ethylenically unsaturated group-containing monomer (B) is usually used in an amount of 1 to 100 parts by weight, preferably 5 to 80 parts by weight, based on 100 parts by weight of the oxidized polyolefin particles (A).
It is contained in parts by weight.

The reducing substance (C) used in the present invention has an effect of improving the graft amount in the obtained modified polyolefin particles.

Examples of such reducing substances include iron (II) ions, chromium ions, cobalt ions, nickel ions,
Palladium ion, sulfite, hydroxylamine, addition of such _{hydrazine, -SH, -SO 3 H, -NHNH} 2, -COCH
Organic compounds containing a group such as (OH)-are exemplified.

Specific examples of such a reducing substance (C) include:
Ferrous chloride, potassium dichromate, cobalt chloride, cobalt naphthenate, palladium chloride, ethanolamine, diethanolamine, N, N-dimethylaniline hydrazine,
Ethyl mercaptan, benzenesulfonic acid and p-toluenesulfonic acid are exemplified.

The reducing substance (C) is usually used in an amount of 0.001 to 100 parts by weight of the oxidized polyolefin particles.
It is used in a proportion of 5 parts by weight, preferably 0.1 to 3 parts by weight.

In the present invention, the polyolefin particles (A) are subjected to the above-mentioned ethylenically unsaturated group-containing monomer (A) under a gas phase condition under which the oxidized polyolefin particles (A) can substantially maintain the particle shape. By grafting B) in the presence of the reducing substance (C), modified polyolefin particles can be obtained.

Here, "the gas-phase conditions under which the oxidized polyolefin particles can substantially maintain their particle shape" means that the heating temperature is set to a temperature lower than the melting point of the oxidized polyolefin particles. This means that the reaction is performed under a gas phase condition, and that the reaction is performed under a gas phase condition in which the oxidized polyolefin particles are not dissolved in a solvent or the like.

In this graft polymerization reaction, for example, predetermined amounts of oxidized polyolefin particles (A), an ethylenically unsaturated group-containing monomer (B), and a reducing substance (C) are charged into a reaction vessel, A temperature lower than the melting point of the treated polyolefin particles (A), preferably 50 to 140
C., more preferably by mixing while heating to a temperature of 60 to 120.degree.

Under the above temperature conditions, the reaction time of the graft reaction is usually set in the range of 0.5 to 15 hours, preferably 1 to 10 hours.

Such a graft polymerization reaction is usually performed in an inert gas atmosphere such as nitrogen gas.

The graft amount of the graft group derived from the ethylenically unsaturated group-containing monomer in the modified polyolefin particles thus prepared is usually in the range of 0.5 to 50% by weight, preferably 5 to 40% by weight. is there.

Such a graft group is, when the oxidized polyolefin particles (A) are composed of a crystalline part and an amorphous part,
The polyolefin particles (A) tend to be preferentially introduced into the amorphous part rather than the crystalline part. In the modified polyolefin particles into which the graft group has been introduced, mechanical strength such as impact strength is improved.

Incidentally, by the introduction of the graft group as described above, the average particle size, geometric standard deviation, apparent bulk density and the like of the polyolefin particles do not substantially fluctuate, but the melt flow rate tends to change, and ASTM D 1238 230 according to
Melt flow rate measured in ° C is usually 0.1-100 g / 10
Min, preferably in the range of 0.5 to 80 g / 10 min.

The modified polyolefin particles prepared as described above can be used alone or together with other resins. As the other resin, a thermoplastic resin is used.Examples of such a thermoplastic resin include polyethylene terephthalate, polyester such as polybutylene terephthalate, polyamide, polycarbonate, polystyrene, high-impact polystyrene, ABS, and AES. , MBS, PMMA, styrene-maleic anhydride copolymer, polyphenylene ether, vinyl chloride and the like. When used with such a thermoplastic resin, a polymer alloy having very excellent properties can be obtained.

The modified polyolefin particles obtained by the method of the present invention may further include, if desired, an inorganic filler, an organic filler, a heat stabilizer, a weathering stabilizer, an antistatic agent, an anti-slip agent, an anti-blocking agent, and an anti-fogging agent. And additives such as lubricants, pigments, dyes, natural oils, synthetic oils and waxes.

For example, as the inorganic filler, a powdery filler such as talc or titanium oxide is preferably used.

The modified polyolefin particles obtained by the method of the present invention are particularly excellent in mechanical properties such as impact resistance and rigidity, and have a good appearance, and can be formed into a molded article having an excellent balance of various properties. .

Therefore, the modified polyolefin particles obtained by the method of the present invention require, in addition to ordinary uses of polyolefin, particularly mechanical strength such as filler-reinforced PP, ABS resin, and modified polyphenylene oxide. It can be preferably used for applications, and specifically, can be suitably used as engineering plastics, vehicle parts, home appliance housings, OA equipment housings, and the like.

Effect of the Invention In the present invention, when preparing modified polyolefin particles as described above, polyolefin particles (A) oxidized in the gas phase and an ethylenically unsaturated group-containing monomer (B)
Are mixed and used in the presence of the reducing substance (C). By mixing and using the polyolefin particles (A) thus oxidized in the gas phase and the ethylenically unsaturated group-containing monomer (B) in the presence of the reducing substance (C), the conventional method can be used. A modified polyolefin with a large graft amount that can be used as a molded product with excellent mechanical properties such as impact strength and good surface appearance without using a reactor that requires extremely high pressure resistance such as an autoclave Can be manufactured efficiently.

In addition, in the present invention, since both the step of oxidizing the polyolefin particles and the step of modifying the polyolefin particles (A) obtained in the oxidizing step are performed in the gas phase, both steps must be performed continuously. Can be.

Then, by blending the modified polyolefin particles thus obtained with another resin, a molded article having excellent mechanical properties such as impact resistance can be prepared.

Next, the present invention will be described with reference to examples. However, the present invention should not be construed as being limited by these examples.

[Evaluation Method] In the present invention, the properties of the modified polyolefin particles were measured as follows.

Initial flexural modulus (FM) According to JIS-K7203, using a 3.2 mm thick test piece at 23 ° C
Was measured.

Flexural yield stress (FS) Measured under the same conditions as FM according to JIS-K7203.

IZ impact strength Measured using a 3.2 mm thick test piece according to JIS-K7110.

Heat deformation temperature (HDT) Measured using a 6.4 mm thick test piece according to JIS-K7207.

Rockwell hardness: Measured using a 3.2 mm thick test piece according to JIS-K7207.

Appearance of Molded Product The surface appearance of an injection molded body of 12 cm × 12 cm × 0.32 cm was evaluated by visual observation in the following two stages.

：: No flow mark ×: With flow mark Example 1 and Example 2 Crystalline propylene homopolymer particles A (MFR = 0.3 g / 10
Min) To 100 parts by weight, add a solution prepared by dissolving 0.05 parts by weight of benzoyl peroxide in 5 parts by weight of toluene, mix well, and use a gear oven set at a temperature of 90 ° C. for the time shown in Table 1. Oxidation treatment was performed.

Next, 100 parts by weight of the above-mentioned oxidized propylene homopolymer particles were charged into a stainless steel autoclave equipped with a spiral double ribbon blade, and completely replaced with nitrogen in the system, 43 parts by weight of styrene and cobalt naphthenate were used. 0.
4 parts by weight were charged.

Then, after stirring at room temperature for 1 hour, the temperature in the system was raised to 100 ° C. over 1 hour, and the mixture was further stirred at this temperature for 6 hours to complete the reaction to obtain graft polymer particles. . The styrene graft amount and MFR of the graft polymer particles are shown in Table 1.

In the present invention, the graft amount is obtained by dissolving the co-grafted polymer particles in xylene at 130 ° C. and throwing this solution into a large amount of methyl ethyl ketone to precipitate a polymer.
The precipitated polymer was filtered and washed to obtain a purified polymer, and then a press film was prepared using the obtained purified polymer, and the absorbance at 1600 cm ^{-1 was} measured from the IR spectrum measurement result of the film. Then, it was determined from the absorbance measured as described above based on a calibration curve prepared in advance.

The co-graft polymer particles A obtained as described above are supplied to an injection molding machine (manufactured by Toshiba Corporation, IS-50EP), and are injection-molded at a cylinder temperature of 210 ° C. and a mold temperature of 60 ° C. A test piece was obtained.

 Table 1 shows the physical properties of the test piece.

Examples 3 and 4 As raw material polyolefin, MFR = 10 g / 10 min, ethylene content 25 mol%, 23 ° C., n-decane soluble component amount 25 wt%
The reaction was carried out in the same manner as in Examples 1 and 2, except that propylene / ethylene block copolymer B was used to obtain graft polymer particles.

Comparative Example 1 Propylene / ethylene block copolymer B was used as a raw material polyolefin without oxidation, and reacted under the same conditions as in Example 1 to obtain graft polymer particles.

 The results are shown in Table 1.

Comparative Example 2 Example 4 was repeated except that cobalt naphthenate was not used.
The reaction was carried out in the same manner as described above to obtain graft polymer particles.

 The results are shown in Table 1.

Claims (2)

(57) [Claims] A polyolefin particle (A) subjected to a gas phase oxidation treatment and an ethylenically unsaturated group-containing monomer (B) are mixed in the presence of a reducing substance (C), and the polyolefin particles (A) are mixed. Is heated under an inert gas phase condition capable of substantially maintaining the particle shape. 2. The polyolefin particles (A) subjected to the gas phase oxidation treatment are added in an amount of 0.0
2. A particle prepared by reacting 1 to 10 parts by weight of an organic peroxide in a gas phase.
The method for producing modified polyolefin particles according to the above item.