JPH0826189B2 - Method for producing modified propylene-based polymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a modified propylene-based polymer. More specifically, a phosphite-based compound specific to a propylene-based polymer (hereinafter referred to as compound A) containing 5 ppm or more of titanium content or 0.5 ppm or more of vanadium content of a catalyst residue.
Say. ), A thioether-based antioxidant and a radical generator are blended in a specific amount and melt-kneaded at a temperature of 150 ° C. to 300 ° C. for the production of a modified propylene-based polymer.

[Conventional technology]

In general, propylene-based polymers are relatively inexpensive and have excellent mechanical properties, so that they are used for the production of various molded products such as injection molded products, hollow molded products, films, sheets and fibers. However, although the propylene-based polymer is molded and processed at a temperature higher than the melting point of the propylene-based polymer,
At that time, it is subjected to oxidative deterioration due to heat at the time of melt-kneading, and the molecular chain of the propylene-based polymer is broken, resulting in deterioration of processability and mechanical strength, and problems of coloring and odor due to oxidative deterioration. In particular, a propylene-based polymer has a tertiary carbon that is easily oxidized in the polymer, and thus is easily subjected to thermal oxidative deterioration due to melt-kneading during molding and also has a thermal stability during practical use. Also has a problem. Therefore, in order to prevent thermal oxidative deterioration during melt kneading, 2,6-di-
Low molecular weight phenolic antioxidants such as t-butyl-p-cresol (BHT), and high molecular weight phenolic antioxidants are widely used to impart thermal stability during practical use.

However, when the propylene-based polymer containing the above-mentioned phenolic antioxidant is melt-kneaded, the phenol-based antioxidant used is oxidized during melt-kneading by the complex compound of titanium or vanadium which is the catalyst residue in the propylene-based polymer. There is a problem that a quinone compound is produced and the resulting propylene-based polymer is colored. In the process of studying the coloring property of a propylene-based polymer containing a large amount of titanium or vanadium as a catalyst residue, the present inventors have found that a propylene-based polymer containing a large amount of titanium or vanadium as a catalyst residue is added to the propylene-based polymer. Even if the above-mentioned phenolic antioxidant is blended and melt-kneaded, coloring does not occur which is a practical problem, but a propylene-based polymer blended with such a phenolic antioxidant is used in the presence of a radical generator. When the melt kneading process below is performed and reformed,
It was found that the resulting modified propylene polymer was markedly colored, and the propylene polymer was first blended with a polyol or a partial ester of a polyol and a fatty acid and a phenolic antioxidant, and melt-kneaded in the presence of a radical generator. A method for producing a modified propylene-based polymer (Japanese Patent Application No. 61-96019 and Japanese Patent Application No. 61-157315) has been proposed.

Further, in order to improve the molding processability of the propylene-based polymer, the propylene-based polymer is melt-kneaded in the presence of a radical generator for degradation, that is, the molecular weight of the propylene-based polymer is reduced to reduce the propylene-based polymer. Methods for modifying coalescence are well known.

[Problems to be solved by the invention]

The present inventors previously disclosed Japanese Patent Application No. 61-96019 and Japanese Patent Application No. 61-96019.
-157315, without satisfying the method for producing a modified propylene-based polymer, a propylene-based polymer containing a large amount of titanium or vanadium as a catalyst residue is melt-kneaded in the presence of a radical generator. Further intensive research was conducted on a method for obtaining a modified propylene-based polymer which is not colored. As a result, the titanium content of the catalyst residue was 5 ppm.
When a specific amount of the above phosphite compound (hereinafter referred to as compound A), a thioether antioxidant and a radical generator is added to a propylene polymer containing 0.5 ppm or more of vanadium, and melt-kneaded, coloring occurs. Based on this finding, it was found that a modified propylene-based polymer having a thermal oxidation inhibitor during melt-kneading and a thermal stability during practical use can be practically obtained without any problem, and the present invention was completed based on this finding.

As is clear from the above description, the object of the present invention is to make the titanium content of the catalyst residue 5 ppm or more or the vanadium content 0.5 p
Compound A, a thioether-based antioxidant and a radical generator are added to a propylene-based polymer containing pm or more,
It is intended to provide a method for producing a modified propylene-based polymer which is free from coloring by melt-kneading.

[Means for Solving Problems] The present invention has the following configurations.

Titanium content of catalyst residue is 5ppm or more or vanadium content
0.01 to 1 part by weight of a phosphite compound (hereinafter referred to as compound A) represented by the following general formula [I] and a thioether-based antioxidant are used with respect to 100 parts by weight of a propylene polymer containing 0.5 ppm or more. A method for producing a modified propylene-based polymer, which comprises blending 0.001 to 0.5 part by weight of a radical generator and melt-kneading at 150 ° C to 300 ° C.

[Wherein, R ₁ is hydrogen, an alkyl group having 1 to 3 carbon atoms or —CH ₂ —CH (CH ₃ ) —R ₄ {R ₄ is —OP (OR ₅ ) ₂
(R ₅ is an alkyl group having 8 to 18 carbon atoms)}. Also,
R ₂ and R ₃ represent the same or different alkyl groups having 1 to 8 carbon atoms. The propylene-based polymer used in the production method of the present invention has a titanium content of the catalyst residue of 5 ppm or more or a vanadium content of 0.5 ppm.
A propylene-based polymer which is obtained by a solution polymerization method using a saturated hydrocarbon solvent, a bulk polymerization method, a gas phase polymerization method or a polymerization method by a combination of a bulk polymerization method and a gas phase polymerization method is there. In the production method of the present invention, a propylene-based polymer having a titanium residue content of the catalyst residue of less than 5 ppm or a vanadium content of less than 0.5 ppm may be used. The propylene-based polymer used in the present invention has a titanium content of 5 p
A propylene-based polymer containing pm or more or 0.5 ppm or more of vanadium, which is a homopolymer of propylene, propylene and ethylene, butene-1, pentene-1, 4-methyl-pentene-1, hexene-1, octene. Of a crystalline random copolymer or a crystalline block copolymer with one or more α-olefins such as -1 and a copolymer of propylene and vinyl acetate, an acrylate ester or the like. Examples thereof include saponified products, copolymers of propylene and unsaturated carboxylic acids or their anhydrides, reaction products of the copolymers and metal ion compounds, etc. Of course, these propylene-based polymers may be used alone. That is, two or more kinds of propylene-based polymers can be mixed and used. In addition, the above-mentioned propylene-based polymer and various synthetic rubbers (for example, ethylene-propylene copolymer rubber, ethylene-propylene-non-conjugated diene copolymer rubber, polybutadiene, polyisoprene, chlorinated polyethylene, chlorinated polypropylene, styrene-ptadiene-based rubber). Rubber, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer, styrene-propylene-butylene-styrene block copolymer, etc.) or thermoplastic Synthetic resins (for example, polyolefins other than propylene-based polymers such as polyethylene, polybutene, poly-4-methylpentene-1), polystyrene, styrene-acrylonitrile copolymers, acrylonitrile-butadiene-styrene. Polymers, polyamides, polyethylene terephthalate, polybutylene terephthalate, may also be used a mixture of polyvinyl chloride, etc.). Propylene homopolymer, crystalline ethylene-propylene random copolymer, crystalline ethylene-propylene block copolymer, crystalline flopyrene-butene-1 random copolymer, crystalline ethylene-propylene-butene-1 ternary copolymer A propylene-based polymer which is a coalesced product, a crystalline propylene-hexene-butene-13 group copolymer or a mixture of two or more thereof, and which contains 5 ppm or more of titanium content or 0.5 ppm or more of vanadium content of the catalyst residue is particularly preferably used. To be

Examples of the compound A used in the present invention include 1,1'-bis (4-di-nonylphosphite-3,5-di-t-butylphenyl) methane and 1,1'-bis (4-di-tri). Decylphosphite-3,5-di-t-butylphenyl) methane, 1,1'-bis (4-di-stearylphosphite-3,5-di-t-butylphenyl) methane, 1,1'- Bis (3-methyl-4-di-nonylphosphite-5-
t-butylphenyl) methane, 1,1'-bis (3-methyl-4-di-tridecylphosphite-5-t-butylphenyl) methane, 1,1'-bis (3-methyl-4-)
Di-stearyl phosphite-5-t-butylphenyl) methane, 4,4'-butylidene-bis (3-methyl-)
6-t-butylphenyl) di-nonylphosphite,
4,4'-butylidene-bis (3-methyl-6-t-butylphenyl) di-tridecyl phosphite, 4,4'-
Butylidene-bis (3-methyl-6-t-butylphenyl) di-stearyl phosphite, 1,1'-bis (2
-Di-nonylphosphite-3-t-butyl-5-methylphenyl) methane, 1,1'-bis (2-di-tridecylphosphite-3-t-butyl-5-methylphenyl) methane, 1 , 1'-bis (2-di-stearylphosphite-3-t-butyl-5-methylphenyl) methane, 1,1'-bis (2-di-nonylphosphite-
3-t-butyl-5-ethylphenyl) methane, 1,1 ′
-Bis (2-di-tridecylphosphite-3-t-
Butyl-5-ethylphenyl) methane, 1,1'-bis (2-di-stearylphosphite-3-t-butyl-5-ethylphenyl) methane, 1,1'-bis (2-di-nonylphosphine Phyto-3,5-di-t-butylphenyl) methane, 1,1'-bis (2-di-tridecylphosphite-3,5-di-t-butylphenyl) methane, 1,
1'-bis (2-di-stearyl phosphite-3,5-
Di-t-butylphenyl) methane, 2,2'-bis (2-
Di-nonylphosphite-4,6-di-t-butylphenyl) ethane, 2,2'-bis (2-di-tridecylphosphite-4,6-di-t-butylphenyl) ethane,
2,2'-bis (1-di-stearyl phosphite-4,6
-Di-t-butylphenyl) ethane, 1,1'-bis (2
-Di-nonyl phosphite-3-t-octyl-5-
Methylphenyl) methane, 1,1'-bis (2-di-tridecylphosphite-3-t-octyl-5-methylphenyl) methane, 1,1'-bis (2-di-stearylphosphite-3 -T-octyl-5-methylphenyl) methane, 1,1,3-tris (2-methyl-4-di-nonylphosphite-5-t-butylphenyl) butane, 1,1,3-tris (2 -Methyl-4-di-tridecylphosphite-5-t-butylphenyl) butane, 1,
Examples thereof include 1,3-tris (2-methyl-4-di-stearylphosphite-5-t-butylphenyl) butane and a mixture of two or more thereof. In particular 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl) di-tridecylphosphite or 1,1,3-tris (2-methyl-4-di-tridecylphosphite-
5-t-butylphenyl) butane and mixtures of two or more thereof are preferred. As the thioether antioxidant, dilauryl thiodipropionate, ditridecyl thiodipropionate, dimyristyl thiodipropionate, dicetyl thiodipropionate, distearyl thiodipropionate, dilauryl thiodibutyrate,
Ditridecyl thiodibutyrate, dimyristyl thiodibutyrate, dicetyl thiodibutyrate, distearyl thiodibutyrate, pentaerythritol-β-lauryl-thiodipropionate, lauryl stearyl thiodipropionate, pentaerythritol-tetrakis-
(3-laurylthiopropionate), pentaerythritol-tetrakis- (3-myristylthiopropionate), pentaerythritol-tetrakis- (3-stearylthiopropionate), bis (4-t-amylphenyl) sulfide , Distearyl disulfide, thioethylene glycol-bis (β-aminocrotonate), poly ((1,4-bis (hydroxymethyl) cyclohexane-thio-dipropionate)) and mixtures of two or more thereof. In particular dimyristyl thiodipropionate, distearyl thiodipropionate,
Pentaerythritol-tetrakis- (2-laurylthiopropionate) and mixtures of two or more thereof are preferred. The compounding ratio of the compound A and the thioether antioxidant is 0.01 to 1 part by weight, preferably 0.05 to 0.5 part by weight, based on 100 parts by weight of the propylene polymer. If the amount is less than 0.01 parts by weight, the effect of preventing the thermal oxidative deterioration of the modified propylene polymer during melt-kneading and the thermal stability during practical use are insufficient, and the amount may exceed 1 part by weight. However, it is not practical because the effect of preventing further thermal oxidative deterioration during melt-kneading and the improvement of thermal stability during practical use cannot be expected, and it is uneconomical.

As the radical generator used in the present invention, the decomposition temperature is preferably not too low to obtain a uniform composition, and the temperature for obtaining a half-life of 10 hours is 70 ° C or higher, preferably 100 ° C or higher. Benzoyl peroxide, t-butyl perbenzoate, t-butyl peracetate, t-butyl peroxyisopropyl carbonate, 2,5-di-methyl-2,5-di- (benzoylperoxy) hexane, 2, 5-di-methyl-2,5-di- (benzoylperoxy) hexyne-3, t-butyl-di-peradipate, t-butylperoxy-3,5,5-trimethyl ester hexanoate, methyl- Ethyl ketone peroxide, cyclohexanone peroxide, di-t-butyl peroxide, dicumyl peroxide, 2,5-di-methyl-2,5-di- (t-butylperoxide) Xy) hexane, 2,5-di-methyl-2,5-di- (t-butylperoxy) hexyne-3,1,3-bis- (t-butylperoxyisopropyl) benzene, t-butylcumyl Peroxide, 1,1-bis- (t-butylperoxy) -3,
3,5-Trimethylcyclohexane, 1,1-bis- (t-butylperoxy) cyclohexane, 2,2-bis- (t-
Butylperoxy) butane, p-menthane hydroperoxide, di-isopropylbenzene hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, p-cymen hydroperoxide, 1,1,3,3-tetra- Methylbutyl hydroperoxide or 2,5-di-methyl-2,5-di-
An organic peroxide such as (hydroperoxy) hexane can be exemplified. Especially 2,5-di-methyl-2,5-di- (t-butylperoxy) hexane, 2,5-di-methyl-2,5-di- (t-butylperoxy) hexyne-3 or 1 , 3-
Bis- (t-butylperoxyisopropyl) benzene is preferred. The mixing ratio of the radical generator is usually 0.001 to 0.5 part by weight, preferably 0.01 to 0.2 part by weight, relative to 100 parts by weight of the propylene polymer. The melt kneading method is carried out at 150 ° C. to 3 ° C. with various melt kneading devices described later.
It is carried out at a temperature of 00 ° C, preferably 180 ° C to 270 ° C. If the melt-kneading temperature is less than 150 ° C, sufficient reforming will not be performed and 300 ° C
If it exceeds the range, the thermal oxidative deterioration of the propylene-based polymer is promoted, and the coloration of the propylene-based polymer becomes remarkable, which is not preferable.

In the production method of the present invention, various additives usually added to a propylene-based polymer, such as phosphorus-based oxidation, are added to a propylene-based polymer containing a titanium residue of a catalyst residue of 5 ppm or more or a vanadium content of 0.5 ppm or more. Inhibitor, light stabilizer,
Clarifying agent, nucleating agent, lubricant, antistatic agent, antifogging agent, antiblocking agent, anti-drop agent, pigment, heavy metal deactivator (copper damage inhibitor), dispersant or neutralizer for metal soaps, etc. Agent,
Inorganic fillers (eg talc, mica, clay, wollastonite, zeolite, asbestos, calcium carbonate,
Aluminum hydroxide, magnesium hydroxide, silicon dioxide, titanium dioxide, zinc oxide, magnesium oxide, zinc sulfide, barium sulfate, calcium silicate, glass fiber,
The inorganic filler surface-treated with a surface treatment agent such as carbon fiber, potassium titanate, metal fiber) or a coupling agent (eg, silane-based, titanate-based, boron-based, aluminate-based, zircoaluminate-based) Alternatively, an organic filler (for example, charcoal, pulp, waste paper, synthetic fiber, natural fiber, etc.) can be blended and used within a range not impairing the object of the present invention.

In the production method of the present invention, the compound A, the thioether-based antioxidant, the radical generator and the usual propylene-based polymer are added to the propylene-based polymer containing 5 ppm or more of titanium content or 0.5 ppm or more of vanadium content of the catalyst residue. Mix the specified amount of each of the above-mentioned various additives using an ordinary mixing device such as a Henschel mixer (commercial product), a super mixer, a ribbon blender, or a Banbury mixer at a temperature at which the compounded radical generator does not decompose. Then, using a normal single-screw extruder, a twin-screw extruder, a Brabender or a roll, the melt-kneading temperature is 150 ° C to 300 ° C, preferably 180 ° C.
It is carried out by melt-kneading treatment at ˜270 ° C.

[Action]

In the present invention, the compound A has the functions of both a phenol-based antioxidant and a phosphorus-based antioxidant, and acts as a radical scavenger and a peroxide decomposer to prevent thermal oxidative deterioration during melt kneading and to be used practically. It contributes to the improvement of thermal stability. Further, the thioether antioxidant serves as a peroxide decomposer to improve the thermal stability during practical use, and the radical generator generates radicals by the melt-kneading process, that is, heating, and the main chain of the propylene polymer is cleaved. It is well known that the propylene-based polymer acts to improve the moldability by reducing the molecular weight of the propylene-based polymer.

In the production method of the present invention, the above-mentioned compound A does not cause coloring because the compound A is different from a usual phenolic antioxidant because the hydroxyl group of the hindered phenol forms a phosphite. It is considered that this is because a coloring atom group such as a quinone compound as seen in the antioxidant process of the inhibitor is not formed.

〔effect〕

The modified propylene-based polymer obtained by the production method of the present invention is different from the modified propylene-based polymers disclosed in Japanese Patent Application No. 61-96019 and Japanese Patent Application No. 61-157315 filed by the present inventors. Further, since it has no coloring and the molding processability and the like are improved, it can be suitably used for producing a desired molded article by various molding methods such as an injection molding method, an extrusion molding method and a blow molding method.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The evaluation methods used in Examples and Comparative Examples were as follows.

Colorability: YI (Yellowness Index) of the obtained pellets was measured (in accordance with JIS K 7103), and the colorability was evaluated based on the value of YI.

 The smaller this value is, the less the coloring is.

Examples 1-12, Comparative Examples 1-3 As a propylene-based polymer, MFR (load at 230 ℃
Discharge amount of molten resin for 10 minutes when 2.16 kg is added) 2.0 g
/ 10 minutes of unstabilized powdery propylene homopolymer (titanium content 30 ppm) 100 parts by weight as compound A
4,4'-butylidene-bis (3-methyl-6-t-butylphenyl) di-tridecyl phosphite or 1,
1,3-Tris (2-methyl-4-di-tridecylphosphite-5-t-butylphenyl) butane, dimyristylthiodipropionate, distearylithiodipropionate or pentaerythritol as a thioether antioxidant -Tetrakis- (3-laurylthiopropionate), 2,5-di-methyl-2,5-di- (t-butylperoxy) hexane or 1,3-bis- (t-butyl) as a radical generator Peroxyisopropyl) benzene and other additives were put in the Henschel mixer (trade name) in the proportions shown in Table 1 below, and the mixture was stirred and mixed for 3 minutes, and then a single screw extruder with a diameter of 40 mm was used. The mixture was melt-kneaded at 200 ° C, modified, and pelletized. Further, as Comparative Examples 1 to 3, 100 parts by weight of an unstabilized powdery propylene homopolymer having an MFR of 2.0 g / 10 minutes (titanium content of 30 ppm) was added to each of the additives described in Table 1 below. A fixed amount was compounded and melt-kneaded according to Examples 1 to 12 to obtain modified pellets.

The obtained pellets were used to evaluate the colorability by the above-mentioned test method. The results are shown in Table 1.

Examples 13 to 24, Comparative Examples 4 to 6 As a propylene-based polymer, MFR 7.0 g / 10 min unstabilized powdery crystalline ethylene-propylene random copolymer (ethylene content 2.5% by weight, titanium content Amount 33p
pm) 100 parts by weight of 4,4'-butylidene-as compound A
Bis (3-methyl-6-t-butylphenyl) di-tridecylphosphite or 1,1,3-tris (2-methyl-4-di-tridecylphosphite-5-t-butylphenyl) butane, Dimyristyl thiodipropionate, distearyl thiodipropionate or pentaerythritol-tetrakis- (3-lauryl thiopropionate) as a thioether antioxidant and 2,5-di-methyl-2,5 as a radical generator. -Di- (t-butylperoxy) hexane or 1,3-bis- (t-
Butyl peroxyisopropyl) benzene and other additives in the prescribed amounts shown in Table 2 below are placed in a Henschel mixer (trade name), and the mixture is stirred and mixed for 3 minutes and then a single screw extruder with a diameter of 40 mm. Was melt-kneaded at 200 ° C. to modify and pelletize. In addition, as Comparative Examples 4 to 6, 100 parts by weight of powdery crystalline ethylene-propylene random copolymer (ethylene content 2.5% by weight, titanium content 33 ppm) in which MFR is 7.0 g / 10 minutes and which is not stabilized will be described later. A prescribed amount of each of the additives shown in Table 2 was mixed and melt-kneaded according to Examples 13 to 24 to obtain modified pellets.

The obtained pellets were used to evaluate the colorability by the above-mentioned test method. The results are shown in Table 2.

Examples 25-36, Comparative Examples 7-9 As a propylene-based polymer, MFR 4.0 g / 10 min unstabilized powdery crystalline ethylene-propylene block copolymer (ethylene content 8.5% by weight, titanium content Amount 33pp
m) 100 parts by weight of 4,4'-butylidene-as compound A
Bis (3-methyl-6-t-butylphenyl) di-tridecylphosphite or 1,1,3-tris (2-methyl-4-di-tridecylphosphite-5-t-butylphenyl) butane, Dimyristyl thiodipropionate, distearyl thiodipropionate or pentaerythritol-tetrakis- (3-lauryl thiopropionate) as a thioether antioxidant and 2,5-di-methyl-2,5 as a radical generator. -Di- (t-butylperoxy) hexane or 1,3-bis- (t-
Butyl peroxyisopropyl) benzene and other additives in the specified amounts in the Henschel mixer (trade name) at the blending ratios shown in Table 3 below, after stirring and fitting for 3 minutes, single screw extrusion with a diameter of 40 mm The mixture was melt-kneaded at 200 ° C. in a machine to be modified and pelletized. In addition, as Comparative Examples 7 to 9, 100 parts by weight of powdery crystalline ethylene-propylene block copolymer (ethylene content 8.5% by weight, titanium content 33 ppm) in which MFR is not stabilized at 4.0 g / 10 min will be described later. Predetermined amounts of the additives shown in Table 3 were mixed and melt-kneaded according to Examples 25 to 36 to obtain modified pellets.

The obtained pellets were used to evaluate the colorability by the above-mentioned test method. The results are shown in Table 3.

Examples 37 to 48, Comparative Examples 10 to 12 As a propylene-based polymer, MFR 7.0 g / 10 min unstabilized powdery crystalline ethylene-propylene-butene-1 terpolymer (ethylene content 2.5 % By weight, butene-1 content is 4.5% by weight, titanium content is 33 ppm) and 100 parts by weight of 4,4'-butylidene-bis (3-
Methyl-6-t-butylphenyl) di-tridecyl phosphite or 1,1,3-tris (2-methyl-4-)
Di-tridecyl phosphite-5-t-butylphenyl) butane, dimyristyl thiodipropionate, distearyl thiodipropionate or pentaerythritol-tetrakis- as a thioether antioxidant
(3-laurylthiopropionate), 2,5-di-methyl-2,5-di- (t-butylperoxy) hexane or 1,3-bis- (t-butylperoxyisopropyl) as a radical generator ) Predetermined amounts of benzene and other additives were added to the Henschel mixer (trade name) in the mixing ratios shown in Table 4 below, and the mixture was stirred and mixed for 3 minutes, and then heated to 200 ° C with a single screw extruder having a diameter of 40 mm. It was melt-kneaded, modified, and pelletized. In addition, MFR as Comparative Examples 10 to 12
7.0g / 10min unstabilized powdery crystalline ethylene-propylene-butene-13 terpolymer (ethylene content
2.5% by weight, butene-1 content 45% by weight, titanium content 3
3 ppm) and 100 parts by weight of each of the additives described in Table 4 below were blended and melt-kneaded according to Examples 37 to 48 to obtain modified pellets.

The obtained pellets were used to evaluate the colorability by the above-mentioned test method. The results are shown in Table 4.

Examples 49 to 60, Comparative Examples 13 to 15 As a propylene-based polymer, MFR 4.0 g / 10 min unstabilized powdery crystalline ethylene-propylene block copolymer (ethylene content 16.0% by weight, vanadium-containing) The amount of the compound A is 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl) di-tridecyl phosphite or 1,1,3-tris (2-methyl). -4-Di-tridecyl phosphite-5
-T-butylphenyl) butane, dimyristylthiodipropionate, distearylthiodipropionate or pentaerythritol-tetrakis- (3-laurylthiopropionate) as a thioether antioxidant, and 2,5 as a radical generator. -Di-methyl-2,5-di- (t-butylperoxy) hexane or 1,3-bis- (t-butylperoxyisopropyl) benzene and other additives were added in the predetermined amounts shown in Table 5 below. Put it in the Henschel mixer (trade name) in the mixing ratio described in 3 and
After stirring and mixing for a minute, the mixture was melt-kneaded at 200 ° C. with a single-screw extruder having a diameter of 40 mm, modified, and pelletized. In addition, MFR as Comparative Examples 13 to 15 is 4.0 g / 10 minutes unstabilized powdery crystalline ethylene-propylene block copolymer (ethylene content 16.0 wt%, vanadium content 0.6 ppm) 10
A predetermined amount of each of the additives shown in Table 5 below was added to 0 part by weight, and melt-kneaded in accordance with Examples 49 to 60 to obtain modified pellets.

The obtained pellets were used to evaluate the colorability by the above-mentioned test method. The results are shown in Table 5.

Various compounds and additives shown in Tables 1 to 5 are as follows.

Compound A [I]; 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl) di-tridecyl phosphite Compound A [II]; 1,1,3-tris (2-methyl- 4-di-
Tridecyl phosphite-5-t-butylphenyl)
Butane thioether antioxidant [I]; dimyristyl thiodipropionate thioether antioxidant [II]; distearyl thiodipropionate thioether antioxidant [III]; pentaerythritol-tetrakis- (3-laurylthio Propionate) Radical generator [I]; 2,5-di-methyl-2,5-di-
(T-Butylperoxy) hexane radical generator [II]; 1,3-bis- (t-butylperoxyisopropyl) benzene phenolic antioxidant 1; 2,6-di-t-butyl-p-
Cresol phenolic antioxidant 2; tetrakis [methylene-3-
(3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane polyol compound (partial ester of polyol and fatty acid); pentaerythritol monostearate phosphite compound (phenolic hydroxyl group remains Phosphite compound); bis (p-octyl) phenyl-bis [2-t-butyl-5-methyl-4- [α
-(3-t-Butyl-6-methyl-4-hydroxyphenyl)] butylphenyl] -1,6-hexanediol-
Diphosphite Ca-St; calcium stearate The examples and comparative examples shown in Table 1 are the cases where a propylene homopolymer was used as the propylene polymer. As can be seen from Table 1, in Examples 1 to 12, compound A, a thioether-based antioxidant and a radical generator were blended with a propylene homopolymer containing 30 ppm of titanium in the catalyst residue according to the present invention, and melt kneaded. It was treated and modified. Examples 1 to 12 and Comparative Example 1 (Methods for producing modified propylene-based polymers of Japanese Patent Application No. 61-96019 and Japanese Patent Application No. 61-157315 previously proposed by the present inventors. Compared with those obtained by mixing a polyol and a partial ester of a fatty acid, a phenolic antioxidant and a radical generator, and subjecting the mixture to a melt kneading treatment for modification,
It can be seen that 12 is less colored than Comparative Example 1 and the anti-coloring property is improved. Comparing Comparative Example 2 and Examples 1 to 12 using a phosphite-based compound in which a phenolic hydroxyl group remains in place of the compound A, Comparative Example 2 is markedly colored, and this coloring is the same as that of the phosphite-based compound. It can be seen that the phenolic hydroxyl group is caused by forming a quinone compound. Further, comparing Comparative Examples 3 and 1 to 12 in which the partial ester of the polyol and the fatty acid used in Comparative Example 1 is further added to Comparative Example 2, Comparative Example 3 is similar to Comparative Example 1 in that the coloring property is improved. It turns out that it is less than Examples 1-12.

Tables 2-5 show crystalline ethylene-propylene random copolymers, crystalline ethylene-propylene block copolymers, crystalline ethylene-pyropyrene-butene-1 terpolymers and crystallinity as propylene-based polymers, respectively. The ethylene-propylene block copolymer was used, and the same effects as those described above were confirmed for these.

Therefore, it is understood that the modified propylene-based polymer obtained by the production method of the present invention has no coloration and its moldability is improved.

From this, the modified propylene-based polymer obtained by the production method of the present invention is a compound obtained by blending a compound having a conventionally known coloring preventing effect and performing melt-kneading treatment in the presence of a radical generator for modification. It was found that the anti-coloring property was remarkably superior to that of the above, and the remarkable effect of the present invention was confirmed.

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Claims (6)

[Claims] 1. A propylene-based polymer 100 containing 5 ppm or more of titanium content or 0.5 ppm or more of vanadium content in a catalyst residue.
0.01 to 1 part by weight of a phosphite compound represented by the following general formula [I] (hereinafter referred to as compound A) and a thioether-based antioxidant, and 0.001 to 0.5 part by weight of a radical generator, based on parts by weight. A method for producing a modified propylene-based polymer, which comprises blending and melt-kneading at 150 ° C to 300 ° C. [Wherein, R ₁ is hydrogen, an alkyl group having 1 to 3 carbon atoms or —CH ₂ —CH (CH ₃ ) —R ₄ {R ₄ is —OP (OR ₅ ) ₂
(R ₅ is an alkyl group having 8 to 18 carbon atoms)}. Also,
R ₂ and R ₃ represent the same or different alkyl groups having 1 to 8 carbon atoms. ] 2. The modified propylene polymer according to claim 1, wherein the alkyl group represented by R ₂ and R ₃ in the general formula [I] is a methyl group or a t-butyl group. Manufacturing method. 3. As compound A, 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl) di-tridecyl phosphite, 1,1,3-tris (2-methyl-4) is used.
-The method for producing a modified propylene-based polymer according to claim (1), which comprises blending di-tridecylphosphite-5-t-butylphenyl) butane or a mixture of two or more thereof. 4. A theoether antioxidant as dimyristyl thiodipropionate, distearyl thiodipropionate, pentaerythritol-tetrakis- (3
-Lauryl thiopropionate) or a mixture of two or more thereof, and the method for producing a modified propylene-based polymer according to claim (1). 5. A radical generator, 2,5-di-methyl-
2,5-di- (t-butylperoxy) hexane, 2,5-di-methyl-2,5-di- (t-butylperoxy) hexyne-3 or 1,3-bis- (t-butyl) Claim (1) in which peroxyisopropyl) benzene is blended.
Item 8. A method for producing a modified propylene-based polymer according to item. 6. A propylene homopolymer, a crystalline ethylene-propylene random copolymer, a crystalline ethylene-propylene block copolymer, a crystalline propylene-butene-1 random copolymer, a crystalline ethylene as a propylene-based polymer. -Propylene-butene-1 terpolymer, crystalline propylene-hexene-butene-1 terpolymer or modified propylene according to claim (1) using a mixture of two or more thereof. Of producing a base polymer.