JPH07233225A - Production of modified propylene polymer - Google Patents

Abstract

PURPOSE:To obtain a modified propylene polymer which is colorless and transparent and is hence extremely useful in applications where colorlessness and transparency are important, e.g. as a molding material or a packaging or container material or in blending with other colorless resin. CONSTITUTION:This process comprises melt-kneading a propylene polymer together with a vinyl monomer to polymerize the monomer, and the reaction is conducted in the presence of a double hydroxide salt of lithium and aluminum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a modified propylene-based polymer having no coloration, and more particularly to a method for producing a modified propylene-based polymer excellent in coloring resistance during production.

[0002]

2. Description of the Related Art Polypropylene is low in cost and excellent in mechanical strength, heat resistance, oil resistance, electric characteristics, etc.
It is used in various applications such as films, fibers and molded products. However, polypropylene does not have polar groups or reactive active groups in its molecular structure and is poorly corrosive to solvents, so it is a resin that has many problems in secondary processing such as printability, adhesiveness and paintability. is there. Therefore, the inventors of the present invention carry out a melt-kneading polymerization reaction of an aromatic vinyl monomer and a polar functional group-containing vinyl monomer in the presence of a propylene polymer in a molten state to obtain mechanical strength, heat resistance, and oil resistance. With the excellent characteristics of polypropylene such as
It was also found that a modified propylene-based polymer composition having excellent printability, adhesiveness, and coatability was obtained (Japanese Patent Laid-Open No. HEI 5)
-209025). This invention states that a stabilizer is required because polypropylene is a radically disintegrating polymer unlike polyethylene. Examples of such stabilizers include phenolic stabilizers, phosphorus stabilizers, metal soaps, hydrotalcites, and the like.

[0003]

[Patent Document 1] Japanese Patent Application Laid-Open No. 5-20902
The modified propylene-based polymer composition described in JP-A No. 5 is colored a little yellow despite having the excellent properties as described above, and the commercial value is impaired. However, there remains a problem that it cannot be used as a molding material. The present inventors conducted research on the type of kneading machine, reaction temperature, reaction time, etc. when performing a melt kneading polymerization reaction of a propylene-based polymer with an aromatic vinyl monomer and a polar group-containing vinyl monomer. However, almost no difference in the degree of coloring of the obtained modified propylene polymer composition was observed.

That is, the problem to be solved by the present invention is
It is an object of the present invention to provide a method for producing a modified propylene-based polymer that does not cause coloration during production.

[0005]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that among known stabilizers used for polypropylene, which is a radical-disintegrating polymer, is calcium stearate. It has been found that various metallic soaps are the cause of coloration during the production of the modified propylene-based polymer.

Therefore, as a result of further intensive studies by the present inventors on alternatives to metal soaps, the use of a lithium aluminum complex hydroxide salt at the time of producing a modified propylene polymer causes no coloration at all. The surprising fact that a modified propylene-based polymer can be obtained was discovered, and the present invention was completed.

That is, the present invention is a modified propylene polymer obtained by melt-kneading and polymerizing an aromatic vinyl monomer and a polar functional group-containing vinyl monomer in the presence of a molten propylene polymer. The present invention provides a method for producing a modified propylene-based polymer having excellent coloring resistance, which comprises reacting in the presence of a lithium aluminum complex hydroxide salt.

The present invention will be described in detail below. (Structure) The propylene-based polymer used in the present invention is a homopolymer of propylene and a copolymer mainly composed of propylene and another olefin or an ethylenic vinyl monomer (each of which has a copolymerization weight of propylene of 75% by weight or more). And a specific example thereof is isotactic polypropylene, propylene-ethylene copolymer, propylene-butene copolymer, maleic anhydride-modified polypropylene, and the like. These propylene-based polymers may be used alone or in combination of two or more.
Further, other polymers can be used as long as the properties of the propylene-based polymer are not impaired.

The vinyl monomer used in the present invention is an aromatic vinyl monomer, a polar functional group-containing vinyl monomer, a vinyl ester monomer or the like, and among them, the aromatic vinyl monomer and the polar group-containing vinyl monomer. It is preferable to use a monomer.

As the aromatic vinyl monomer, for example, styrene, methylstyrene, vinylxylene, ethylvinylbenzene, isopropylstyrene, chlorostyrene,
Dichlorostyrene, bromostyrene, etc. can be illustrated. These may be used alone or in combination of two or more, but among them, styrene is preferably used.

Further, as the polar functional group-containing vinyl monomer used in combination with the aromatic vinyl monomer, epoxy group-containing vinyl monomer, hydroxyl group-containing vinyl monomer, carboxyl group-containing vinyl monomer, amino group Examples thereof include a vinyl monomer containing a vinyl monomer, a vinyl monomer containing an amide group, and a vinyl monomer containing a nitrile group. These may be used alone,
Two or more kinds can be mixed and used, but among them, it is preferable to use an epoxy group-containing vinyl monomer.

Examples of the vinyl monomer containing an epoxy group include glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, and methacryl glycidyl ether. These may be used alone or in a mixture of two or more, but it is particularly preferable to use glycidyl methacrylate.

The amount of the aromatic vinyl monomer added is preferably 50% by weight or less, more preferably 3 to 35% by weight, based on the propylene polymer. If it exceeds 50% by weight, the performance of polypropylene is impaired, which is not preferable.

The amount of the polar functional group-containing vinyl monomer added is
It is preferably 20% by weight or less, and more preferably 0.1 to 10% by weight of the propylene polymer. If it exceeds 20% by weight, reticulation of the product may occur, which is not preferable.

The lithium aluminum complex hydroxide salt of the present invention is represented by the following formula.

[0016]

[Al ₂ Li (OH) ₆ ] _n X · mH ₂ O [In the formula, X is an inorganic or organic anion, n is the valence of the anion X, and m is a number of 3 or less. It is a clathrate compound having a plate-like fine structure, in which lithium ions enter into the vacancy of an aluminum hydroxide octahedral layer having a gibbsite structure.

This compound preferably has an apparent specific gravity (iron cylinder method) of 0.2 to 0.5 and an oil absorption (JIS
K-5101) 30 to 70 (ml / 100 g), decrystallization water starting temperature of 150 ° C. or higher, and BET specific surface area of 1 to 50 (m ² / g).

The method for producing a lithium-aluminum composite hydroxide salt is obtained by reacting a water-soluble aluminum salt with a water-soluble lithium salt and / or lithium hydroxide in the presence of a water-soluble carbonate and an alkali. Examples of the water-soluble aluminum salt include aluminum chloride, aluminum nitrate, aluminum sulfate, etc., and the water-soluble lithium salt is
For example, lithium chloride, lithium nitrate, lithium sulfate,
Examples include lithium carbonate.

This compound can be synthesized in this manner, but it is convenient to use a commercially available compound. For example, Mizucarak (a product of Mizusawa Chemical Industry Co., Ltd.) and the like can be mentioned.

The amount of the lithium aluminum complex hydroxide salt compound added is preferably 0.01 to 10 parts by weight, more preferably 0.02 to 2 parts by weight, particularly preferably 100 parts by weight of the propylene polymer. Is 0.05 to 0.
5 parts by weight.

As a radical polymerization initiator, it is easily dissolved in an aromatic vinyl monomer, and since this reaction is carried out at a melt-kneading temperature of a propylene polymer, decomposition for obtaining a half-life of 1 minute. It is desirable that the temperature is 130 to 250 ° C. Specifically, alkyl peresters such as tertiary butyl peroxy-2-ethylhexanoate and tertiary butyl peroxybenzoate,
1,1-ditertiary butyl peroxy-3,3,5
-Trimethylcyclohexane, 2,2-bis (4,4-
Peroxyketals such as ditertiary butylperoxycyclohexyl) propane, ketone peroxides such as cyclohexanone peroxide, benzoyl peroxide, diacyl peroxides such as 2,4-dichlorobenzoyl peroxide, tertiary butyl peroxyisopropyl Carbonates, percarbonates such as diethylene glycol-bis (tertiary butyl peroxy carbonate), hydroperoxides such as 2,4,4-trimethylperoxy-2-hydroperoxide, dicumyl peroxide, 2,
5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di-
(Tertiary Butyl Peroxy) Hexin-3, α,
Examples thereof include α'-bis- (tertiarybutylperoxyisopropyl) benzene and other dialkyl peroxides. These may be used alone or in combination of two or more. The amount of the radical polymerization initiator added is preferably 0.1 to 10 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of the vinyl monomer.

As other additives, polypropylene is a radical-disintegrating polymer unlike polyethylene, so that a stabilizer is necessary to impart heat resistance. The lithium aluminum complex hydroxide salt compound used in the present invention is used for improving the color resistance,
There is little effect of improving heat resistance. As the stabilizer for imparting heat resistance, a known stabilizer conventionally used for polypropylene can be used, but it does not hinder the polymerization of vinyl monomers,
In addition, it is necessary to consider the kind and the addition amount so as not to cause coloring. Such stabilizers include pentaerythrityl-
Tetrakis (ditertiary butyl hydroxyphenyl) propionate, octadecyl (ditertiary butyl hydroxyphenyl) propionate, thiobis (methyl tert-butyl phenol), hindered phenolic stabilizers such as trimethyl tris (ditertiary butyl hydroxybenzyl) benzene, tetrakis ( Phosphorus stabilizers such as ditertiary butyl phenyl) biphenylene phosphite and tris (di tertiary butyl phenyl) phosphite, acid acceptors such as magnesium oxide and hydrotalcite, and lubricants such as stearic acid and montanic acid. It can be illustrated. These may be used alone or in combination of two or more. The amount of the stabilizer added is preferably 0.01 to 100 parts by weight based on 100 parts by weight of the propylene polymer.
It is 1 part by weight, more preferably 0.05 to 0.5 part by weight.

It is also possible to add a small amount of solvent or water for diluting or degassing the vinyl monomer or the radical initiator.

The melt-kneading polymerization reaction of the propylene polymer with the aromatic vinyl monomer and the polar functional group-containing vinyl monomer is carried out by a Banbury mixer, a pressure type kneader, a closed mixer such as a universal mixer, an extruder. It can be carried out using a continuous kneader such as the above. The closed mixer is suitable for small-scale production, but the extruder is more suitable for industrial production such as granulation, and the twin-screw extruder is particularly preferable because it is easy to supply the raw materials and control the reaction time. .

In the manufacturing method using a closed mixer, for example, a propylene-based polymer in the form of powder or pellets is impregnated with a vinyl monomer and then charged into the mixer. The radical polymerization initiator is preferably dissolved in the vinyl monomer in advance, but it may be directly added to the propylene polymer or the mixture of the propylene polymer and the vinyl monomer. The lithium-aluminum complex hydroxide salt compound of the present invention and other types of stabilizers are preferably mixed in advance with the propylene polymer. And the kneading reaction is preferably 1
The temperature is 60 to 250 ° C, more preferably 170 to 250 ° C, and the kneading time is usually 2 to 15 minutes. After the kneading is completed, the modified propylene polymer obtained is taken out of the mixer and cut into an appropriate shape.

In the production method using an extruder, for example, a propylene-based polymer in the form of powder or pellets is supplied to the extruder and heated to 150 ° C. to 250 ° C. while being pressurized, and the crystalline propylene-based polymer is then heated. Is melted and subjected to a melt-kneading polymerization reaction with a vinyl monomer, and then the modified propylene-based polymer is discharged from a die. The vinyl monomer may be mixed with the propylene-based polymer in advance and supplied to the extruder, or may be supplied to the molten propylene-based polymer using a liquid feeder. Preferably, the vinyl monomer is previously impregnated in the propylene polymer. The radical polymerization initiator is preferably dissolved in the vinyl monomer in advance,
It may be added to the mixture of the propylene polymer and the vinyl monomer using a liquid feeder. The lithium-aluminum complex hydroxide salt and other stabilizers used in the present invention are preferably mixed in advance with the propylene polymer.

The modified propylene-based polymer obtained by the present invention is a thermoplastic resin which can be taken out as it is as a molded product or pellets and is colorless and excellent in mechanical properties and surface properties. Since the polymer is composed of a polar part and a non-polar part, it is also excellent as a compatibility improver with various polymers or with various fillers.

[0028]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following examples and comparative examples do not limit the present invention in any way.

(Example 1) 920 parts by weight of polypropylene powder "Hipol B200P" (manufactured by Mitsui Chemicals, Inc.) and 0.5 parts by weight of "Mizukarak" (manufactured by Mizusawa Chemical Co., Ltd., lithium aluminum complex hydroxide salt), 0.5 parts by weight of Irganox 1010 "(phenolic stabilizer manufactured by Ciba Geigy), 1 part by weight of" Ultranox 626 "(phosphorus stabilizer manufactured by BorgWarner)," Sumilyzer BHT "(phenolic stabilizer manufactured by Sumitomo Chemical Co., Ltd.) Stabilizer) 0.
5 parts by weight were added and mixed by a Henschel mixer. This polypropylene blend is hereinafter referred to as "PP Masterbatch 1". "PP Masterbatch 1" 922.
5 parts by weight of 56 parts by weight of styrene as an aromatic vinyl monomer, 24 parts by weight of glycidyl methacrylate as a vinyl monomer containing a polar functional group, and 2.4 parts by weight of "Perhexin 25B" (manufactured by NOF Corporation) as a radical polymerization initiator. Parts were added and thoroughly mixed and impregnated with a Henschel mixer. A roller mixer of Brabender Plastograph manufactured by Brabender of Germany was set so that the temperature of the mixer section was 220 ° C. "PP masterbatch 1", styrene,
35 parts by weight of a mixture of glycidyl methacrylate and a radical polymerization initiator was supplied to the mixer, and the rotation speed was 40 rpm.
Kneading was performed for 10 minutes. The obtained melt-kneaded product was first visually observed for color. Melt-kneaded product obtained also a styrene content was determined from the calibration curve using the ratio of the 700 cm ^-1 using infrared spectroscopy (attributable to styrene) and 1380 cm ^-1 (assigned to polypropylene), the value Was used to determine the polymerization rate of styrene. The melt-kneaded product was heated at 190 ° C. and 150 kg / cm using a hydraulic press.
Molding was performed under the conditions of ² to obtain a test piece having a thickness of 1 mm. Using the test piece, the yellowness (YI) of the test piece was measured by a reflection method according to JIS K7103, and further, the melt flow index was measured according to ASTM D1238 under a load of 230 ° C. and 2160 g. The above measurement results are shown in Table 1.

(Example 2) 920 parts by weight of polypropylene powder "HIPOL B200P" (manufactured by Mitsui Chemicals, Inc.) and 0.5 parts by weight of "Mizukarak" (manufactured by Mizusawa Chemical Co., Ltd., lithium aluminum complex hydroxide salt compound), "Irganox 1010" (Ciba Geigy Phenolic Stabilizer) 0.5 parts by weight, "Ultranox 626"
(Phosphorus stabilizer manufactured by BorgWarner) 1 part by weight and stearic acid 0.5 part by weight were added and mixed by a Henschel mixer. This polypropylene blend is hereinafter referred to as "PP Masterbatch 2". "PP Masterbatch 2" 9
22.5 parts by weight of styrene 5 as an aromatic vinyl monomer
6 parts by weight, 24 parts by weight of glycidyl methacrylate as a polar functional group-containing vinyl monomer, and 2.4 parts by weight of "Perhexin 25B" (manufactured by NOF CORPORATION) as a radical polymerization initiator were added and thoroughly mixed and impregnated with a Henschel mixer. It was Brabender Plastograph roller mixer manufactured by Brabender, Germany, with a mixer temperature of 220 ° C.
Was set. 35 parts by weight of a mixture of "PP masterbatch 2", styrene, glycidyl methacrylate and a radical polymerization initiator was supplied to the mixer, and the rotation speed was 4
Kneading was carried out at 0 rpm for 10 minutes. The obtained melt-kneaded product was first visually observed for color. Melt-kneaded product obtained also measures the styrene content from the calibration curve using the ratio of 700 cm ^-1 and (attributable to styrene) and 1380 cm ^-1 (assigned to polypropylene) by using an infrared spectroscopic analysis,
The value was used to determine the polymerization rate of styrene. The melt-kneaded product was heated at 190 ° C. and 150 k using a hydraulic press.
Molding was performed under the condition of g / cm ² to obtain a test piece having a thickness of 1 mm.
Using the test piece, the yellowness (YI) of the test piece was measured by a reflection method according to JIS K7103.
The melt flow index was measured according to ASTM D1238 under a load of 60 g. The above measurement results are shown in Table 1.

Example 3 Polypropylene powder "HIPOL B200P" (manufactured by Mitsui Chemicals, Inc.) was added to 920 parts by weight, and "Mizukarak" (manufactured by Mizusawa Chemical Co., Ltd., lithium aluminum complex hydroxide salt) was added thereto in an amount of 0.5 parts by weight. 0.7 parts by weight of Irganox 1010 "(phenolic stabilizer manufactured by Ciba-Geigy) and 1.3 parts by weight of" Ultranox 626 "(phosphorus stabilizer manufactured by BorgWarner) were added and mixed by a Henschel mixer. This polypropylene blend is hereinafter referred to as "PP Masterbatch 3". "P
P masterbatch 3 "922.5 parts by weight, styrene 56 parts by weight as an aromatic vinyl monomer and glycidyl methacrylate 24 parts by weight as a polar functional group-containing vinyl monomer,
2.4 parts by weight of "Perhexin 25B" (manufactured by NOF CORPORATION) was added as a radical polymerization initiator, and the mixture was thoroughly mixed and impregnated with a Henschel mixer. A roller mixer of Brabender Plastograph manufactured by Brabender of Germany was set so that the temperature of the mixer section was 220 ° C. 35 parts by weight of a mixture of "PP masterbatch 3", styrene, glycidyl methacrylate and a radical polymerization initiator was supplied to the mixer, and kneading was performed at a rotation speed of 40 rpm for 10 minutes. The obtained melt-kneaded product was first visually observed for color. The obtained melt-kneaded product was analyzed by infrared spectroscopic analysis to have 700 cm ^-1 (attributable to styrene) and 1380 cm ^-1.
The styrene content was measured from the calibration curve using the ratio with (assigned to polypropylene), and the polymerization rate of styrene was determined using the value. Then, the melt-kneaded product is
Molding was performed at 90 ° C. and under a condition of 150 kg / cm ² to obtain a test piece having a thickness of 1 mm. Using the test piece, JISK7103
The yellowness (YI) of the test piece is measured by the reflection method in accordance with the above, and further, ASTM D123 under 230 ° C. and 2160 g load.
The melt flow index was measured according to 8. The above measurement results are shown in Table 1.

(Comparative Example 1) 920 parts by weight of polypropylene powder "Hipol B200P" (manufactured by Mitsui Chemicals, Inc.), 0.5 parts by weight of calcium stearate, and 0.5 parts by weight of "Irganox 1010" (stabilizer manufactured by Ciba-Geigy). 1 part by weight of "Ultranox 626" (stabilizer manufactured by BorgWarner) was added and mixed by a Henschel mixer. This polypropylene blend is hereinafter referred to as "PP Masterbatch 4". "PP Masterbatch 4"
Styrene 56 as an aromatic vinyl monomer was added to 922 parts by weight.
By weight, 24 parts by weight of glycidyl methacrylate as a polar functional group-containing vinyl monomer and 2.4 parts by weight of "Perhexin 25B" (manufactured by NOF CORPORATION) as a radical polymerization initiator were added and thoroughly mixed and impregnated with a Henschel mixer. .
The roller mixer of Brabender Plastograph manufactured by Brabender of Germany was set so that the temperature of the mixer section was 220 ° C. 35 parts by weight of a mixture of "PP masterbatch 4", styrene, glycidyl methacrylate and a radical polymerization initiator was supplied to the mixer, and the rotation speed was 40 r.
Kneading was performed for 10 minutes at pm. The obtained melt-kneaded product was first visually observed for color. Melt-kneaded product obtained also (attributable to styrene) 700 cm ^-1 using infrared spectroscopy and 1380 cm ^-1 (assigned to polypropylene)
The styrene content was measured from the calibration curve using the ratio of and, and the value was used to determine the polymerization rate of styrene. The melt-kneaded product was heated at 190 ° C. and 150 kg /
It was molded under the condition of cm ² to obtain a test piece having a thickness of 1 mm. Using the test piece, the yellowness (YI) of the test piece was measured by a reflection method according to JIS K7103, and further measured at 230 ° C., 2160 g.
Melt flow index was measured under load according to ASTM D1238. The above measurement results are shown in Table 1.

(Comparative Example 2) Polypropylene powder "Hipol B200P" (manufactured by Mitsui Chemicals, Inc.) 920 parts by weight, calcium stearate 0.5 parts by weight, "Irganox 1010" (stabilizer manufactured by Ciba Geigy) 0.5 parts by weight. Then, 1 part by weight of "Ultranox 626" (stabilizer manufactured by BorgWarner) and 0.5 part by weight of "Sumilyzer BHT" (stabilizer manufactured by Sumitomo Chemical Co., Ltd.) were added and mixed by a Henschel mixer. This polypropylene blend is hereinafter referred to as "PP Masterbatch 5". In 922.5 parts by weight of "PP Masterbatch 5", 56 parts by weight of styrene as an aromatic vinyl monomer, 24 parts by weight of glycidyl methacrylate as a vinyl monomer containing a polar functional group, and "Perhexin 25B" as a radical polymerization initiator (Japan 2.4 parts by weight (available from Yushi Co., Ltd.) was added and thoroughly mixed and impregnated with a Henschel mixer. A roller mixer of Brabender Plastograph manufactured by Brabender of Germany was set so that the temperature of the mixer section was 220 ° C. 35 parts by weight of a mixture of "PP masterbatch 5", styrene, glycidyl methacrylate, and a radical polymerization initiator were supplied to the mixer, and kneading was performed at a rotation speed of 40 rpm for 10 minutes. The obtained melt-kneaded product was first visually observed for color. Moreover, the obtained melt-kneaded product was analyzed by infrared spectroscopy to obtain 70
0 cm ^-1 using the ratio of (attributable to styrene) and 1380 cm ^-1 (assigned to polypropylene) measuring the styrene content from the calibration curve to determine the rate of polymerization of the styrene by using the value. Then, the melt-kneaded product is heated to 190 ° C. using a hydraulic press.
And a thickness of 1 mm when molded under the conditions of 150 kg / cm ²
I got a coupon. Using the sample, the yellowness (YI) of the sample was measured by the reflection method according to JIS K7103, and the melt flow index was measured according to ASTM D1238 under a load of 230 ° C. and 2160 g. The above measurement results are shown in Table 1.

(Comparative Example 3) Polypropylene powder "Hipol B200P" (manufactured by Mitsui Chemicals, Inc.) 920 parts by weight, "Irganox 1010" (stabilizer manufactured by Ciba-Geigy), 0.5 parts by weight, "Ultranox 626" (Borg) 1 part by weight of a stabilizer manufactured by Warner Co., Ltd. was added and mixed by a Henschel mixer. This polypropylene blend is hereinafter referred to as "PP Masterbatch 6". In 921.5 parts by weight of "PP Masterbatch 6", 56 parts by weight of styrene as an aromatic vinyl monomer, 24 parts by weight of glycidyl methacrylate as a vinyl monomer containing a polar functional group, and "Perhexin 25B" as a radical polymerization initiator (Japan 2.4 parts by weight (available from Yushi Co., Ltd.) was added and thoroughly mixed and impregnated with a Henschel mixer. A roller mixer of Brabender Plastograph manufactured by Brabender of Germany was set so that the temperature of the mixer section was 220 ° C. 35 parts by weight of a mixture of "PP masterbatch 6", styrene, glycidyl methacrylate and a radical polymerization initiator was supplied to the mixer, and kneading was performed at a rotation speed of 40 rpm for 10 minutes. The obtained melt-kneaded product was first visually observed for color.
The obtained melt-kneaded product was analyzed by infrared spectroscopic analysis to give 7
00cm ^-1 by using the ratio of (attributable to styrene) and 1380 cm ^-1 (assigned to polypropylene) measuring the styrene content from the calibration curve to determine the rate of polymerization of the styrene by using the value. Then, the melt-kneaded product is heated to 190 ° C. using a hydraulic press.
And a thickness of 1 mm when molded under the conditions of 150 kg / cm ²
I got a coupon. Using the sample, the yellowness (YI) of the sample was measured by the reflection method according to JIS K7103, and the melt flow index was measured according to ASTM D1238 under a load of 230 ° C. and 2160 g. The above measurement results are shown in Table 1.

[0035]

[Table 1] * MFI: Abbreviation for melt flow index From the results shown in Table 1, it is clear that the modified propylene polymer of the present invention is excellent in coloring resistance.

[0036]

INDUSTRIAL APPLICABILITY The present invention makes it possible to provide a modified propylene-based polymer which maintains various physical properties and has no coloration at all. As a result, it can be widely used in applications such as molding materials and packaging materials that place importance on colorless transparency and blending with other resins in colorless formulations. Therefore, the industrial value of the present invention is extremely large.

Claims (7)

[Claims] 1. A method for producing a modified propylene-based polymer obtained by melt-kneading and polymerizing a vinyl monomer in the presence of a propylene-based polymer in a molten state, in the presence of a lithium aluminum complex hydroxide salt. A method for producing a modified propylene-based polymer, which comprises reacting with. 2. A vinyl monomer that undergoes a melt-kneading polymerization reaction,
The method for producing a modified propylene-based polymer according to claim 1, which is an aromatic vinyl monomer or a polar functional group-containing vinyl monomer. 3. A lithium aluminum complex hydroxide salt is represented by the formula: [Al ₂ Li (OH) ₆ ] _n X.mH ₂ O [wherein X is an inorganic or organic anion, and n is It is a valence of anion X and m is a number of 3 or less. ”2. The method for producing a modified propylene-based polymer according to claim 1, wherein. 4. A lithium aluminum complex hydroxide salt having an apparent specific gravity of 0.2 to 0.5 and an oil absorption of 30 to 70 ml / 1.
The method for producing a modified propylene-based polymer according to claim 1, which has a decrystallization water starting temperature of 150 ° C. or higher. 5. The lithium-aluminum composite hydroxide salt comprises a water-soluble aluminum salt, a water-soluble lithium salt, and
The method for producing a modified propylene polymer according to claim 1, which is an inclusion compound obtained by reacting lithium hydroxide with a water-soluble carbonate and an alkali. 6. The amount of the lithium aluminum complex hydroxide salt added, relative to 100 parts by weight of the propylene-based polymer.
The modified propylene-based polymer production method according to claim 1, wherein the amount is 0.01 to 10 parts by weight. 7. The method for producing a modified propylene-based polymer according to claim 1, wherein the addition amount of the polar functional group-containing vinyl monomer is 20% by weight or less of the propylene-based polymer.